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  • Autoradiography  (100)
  • Kidney  (70)
  • Springer  (169)
  • 1970-1974  (169)
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  • Springer  (169)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 33 (1974), S. 41-48 
    ISSN: 1432-0738
    Keywords: Aminotriazole ; Autoradiography ; Teratogenic Effects ; Aminotriazol ; Autoradiographie ; Wirkung auf die Embryogenese
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Aufnahme und Verteilung von Aminotriazol (3-amino-1,2,4-triazol) in den Geweben der Mausföten wurde nach Zufuhr von Aminotriazol — 14C mit Ganzkörper-Autoradiographie studiert. Um die chemische Form der Radioaktivität der Mausföten zu identifizieren, wurden Extrahierungsmethoden in Kombination mit Dünnschichtchromatographie verwendet. Die Wirkung von Aminotriazol auf die Embryogenese der Maus wurde ebenfalls studiert. Aminotriazol war in die Mausföten gelangt und die Verteilung in den Föten war ähnlich derjenigen in den Müttern: Die höchste Akkumulation fand sich in den Geweben mit schneller Zellteilung — wie Knochenmark, Mucosa des Magen-Darmkanals, Thymusdrüse und Milz. Die Mausföten enthielten das meiste Aminotriazol in einer nicht-metabolisierten Form. Die Zufuhr von 1000, 2500 oder 5000 ppm Aminotriazol im Trinkwasser ergab eine markante Verminderung der Gewichtzunahme der Mütter sowie eine Unterentwicklung der Mausföten. Mißbildungen waren nicht zu beobachten. Es wird vorgeschlagen, daß Aminotriazol an einigen Prozessen von sich schnell teilenden Zellen teilnimmt, was die gemeldeten Beobachtungen zur Folge hat.
    Notes: Abstract The absorption and distribution of aminotriazole (3-amino-1,2,4-triazole) in the fetal tissues of mice were studied by whole body autoradiography upon the administration of 14C-labeled aminotriazole. Extraction procedures combined with thin-layer chromatography were used to define the chemical nature of the radioactivity in the fetuses; the effect of aminotriazole on the embryogenesis was also observed. Aminotriazole was passed to the fetuses and the distribution pattern was found to be similar to that of the mothers : the greatest accumulation occurred in tissues with a rapid cell turnover — such as the bone marrow, gastrointestinal mucosa, thymus, and spleen. Most of the aminotriazole was present in the fetus in a non-metabolized form. The administration of 1000, 2500, or 5000 ppm of aminotriazole to the dam's drinking water resulted in a marked decrease in the weight gain of the dams and a pronounced under-deVelopment of the fetuses. Malformations were not observed. It is suggested that aminotriazole participates in some process of rapidly dividing cells which accounts for the reported observations.
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  • 2
    ISSN: 1432-1106
    Keywords: Rabbit retina ; β-alanine uptake ; Autoradiography ; Uptake kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The uptake of β-alanine into rabbit retina was found to proceed without accumulation of metabolites of β-alanine. In vitro, the β-alanine was taken up into cells with the position of amacrines and also in some ganglion cells, similar to the uptake in vivo. The uptake was found to be saturable, temperaturedependent, and inhibitable with ouabain and 2.4-dinitrophenol, indicating an active uptake mechanism. The Km of the β-alanine uptake was 2.57 × 10−5M. For the isomer, α-alanine, the Km was found to be 1.1 × 10−3M. The uptake was not influenced by aspartic acid, glutamic acid, glycine, taurine, histidine, leucine, or a-alanine (all 10−5M). GABA (10−5M) competitively inhibited the β-alanine uptake by 27%.
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  • 3
    ISSN: 1432-1106
    Keywords: Pigeon ; Visual system ; Thalamus ; Autoradiography ; Retrograde degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The distribution of labeled macromolecules was studied within the dorsolateral thalamic nuclei of the pigeon after unilateral intraocular injection of either 3H-proline, 3H-leucine or 3H-fucose. The highest densities of grains were found in nucleus dorsolateralis anterior, pars lateralis at its dorsolateral aspect (DLLd) and in nucleus lateralis anterior (LA) whereas moderate labeling was observed in the ventral aspect of DLL (DLLv) and in nucleus dorsolateralis anterior, pars magnocellularis (DLAmc). No significant label was found on the ipsilateral side. 2. After circumscribed unilateral ablation of the visual wulst, the cells in DLLv were most severely affected by retrograde degeneration, whereas DLLd, DLAmc and LA remained intact. Bilateral ablation of the wulst or combination of wulst damage with section of the supraoptic decussation gave rise to additional degeneration in DLLd, thus suggesting a contralateral retinotelencephalic pathway via DLLv and an ipsilateral retino-telencephalic pathway via DLLd and recrossing via DSO. LA and DLAmc represent relays in retinothalamo-telencephalic pathways of unknown destination. 3. DLLv was confirmed as relay in the contralateral retino-thalamo-hyperstriatal pathway in a combined series of experiments, where the autoradiographic and the retrograde degeneration techniques were applied in the same animal.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 364 (1974), S. 365-369 
    ISSN: 1432-2307
    Keywords: Virus Diseases ; Cytomegalic Inclusion Disease ; Kidney ; Kidney Diseases ; Glomerulonephritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This paper reviews a case of a newborn child which died soon after birth in consequence of a cytomegalic inclusion disease involving the brain, liver, lungs and kidneys. The interest of the case lies in the unusual finding of lesions of the vascular loops of the renal glomeruli. These lesions were represented by focal areas of homogeneous appearance which were strongly basophilic and PAS-positive. Although the nature of these areas has not been completely established, the renal lesions can be tentatively defined as focal, probably necrotizing glomerulonephritis. The association of this type of glomerular lesions with cytomegalic inclusion disease has not been previously reported.
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  • 5
    ISSN: 1433-8580
    Keywords: Kidney ; Concentrating mechanism ; Corticomedullary gradients ; Protein ; Niere ; Konzentrierung ; Corticomedulläre Gradienten ; Protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurden die Albumingradienten der Rattenniere und ihre Beeinflussung durch Furosemid und hypertones Mannit nach mehrtägiger Infusion hyperosmolarer Natriumchloridlösungen untersucht. Als Indicator der Eiweißkonzentrationen diente der an Albumin gebundene Farbstoff Evans blue. Es wurde gefunden: 1. Nach mehrtägiger Natriumkonzentrierung (890 mOsm/l, Urinfluß 1,7 ml/Std) beträgt die Gesamtosmolarität im Gewebe der Papillenspitze 1015 ± 181 mOsm/l und im Sammelrohrurin 1059 ± 42 mOsm/l. Der Eiweißgradient nimmt von der Rinde zur Papillenspitze kontinuierlich auf das 4,25fache der Rindenwerte zu. 2. Nach Furosemid (2 × 0,7 mg/100 g KG) fällt die Gesamtosmolarität im Papillenspitzengewebe auf 344 ± 28 mOsm/l und im Sammelrohrurin auf 385 ± 30 mOsm/l ab. Das stündliche Harnvolumen erhöht sich auf 8,2 ± 2,04 ml. Die Albumine werden nur noch um das 1,8fache ihrer Rindenwerte und zu 35% ihrer ursprünglichen Konzentration angereichert. 3. Unter 20%iger Mannitinfusion (Flußgeschwindigkeit 1,5 ml/Std, Infusionszeit 110 min) fällt die Gesamtosmolarität im Papillenspitzengewebe auf 475 ± 84 mOsm pro Liter und im Sammelrohrurin auf 467 ± 51 mOsm/l ab. Das stündliche Harnvolumen wächst auf 6,4 ± 1,96 ml an. Die Albumine werden nur noch um das 2fache ihrer Rindenwerte und zu 42% ihrer Ausgangskonzentration angereichert. Für die Beeinflussung der corticomedullären Eiweißgradienten durch Mannit und Furosemid werden neben Änderungen der rheologischen Eigenschaften der Erythrocyten Volumen- und osmotisches Substanzangebot an die Vasa recta-Schleifen verantwortlich gemacht. Die Funktion dieser Gegenstromgefäße ist von der osmotischen Substanz- und Wasseraufnahme aus den Henleschen Schleifen und Sammelrohren abhängig.
    Notes: Summary Subject of the examinations were the albumin gradients of the tissue of the rat kidney and the influence of hypertonic mannitol and furosemide on it during long-term infusion of hyperosmolar sodium chloride. As an indicator of the protein concentrations Evans blue dye was injected, which binds to albumen. The following results were obtained: 1. After several days' sodium concentration (890 mOsm/l, urine flow 1.7 cc/hr) the total osmolarity in the tissue of the papillary tip is found to be 1015 ± 181 mOsm per litre and in the collecting ducts 1059 ± 42 mOsm/l. The protein gradients rise continuously towards the papillary tip up to 4.25 times of the cortex values. 2. After injection of furosemide (2 × 0.7 mg/100 g b.w.) the total osmolarity in the papillary tissue decreases to 344 ± 28 mOsm/l and in the collecting ducts to 385 ± 30 mOsm/l. The urine volume per hour increases to 8.2 ± 2.04 cc. Albumin is enriched merely to about 1.8 times of the cortex values and to 35% of its former concentration. 3. During the infusion of hypertonic mannitol (flow-rate 1.5 cc/hr, time of infusion 110 min) the total osmolarity of the papillary tissue decreases to 475 ± 84 mOsm/l and in the collecting ducts to 467 ± 51 mOsm/l. The urine volume rises to 6.4 ± 1.96 cc/hr. Albumin is enriched merely to about twice of the cortex values and to 42% of its original concentration. Besides changes of the rheological characteristics of the red cells, volume and osmotic substance supply to the vasa recta are held responsible for the influence of hypertonic mannitol and furosemide on the corticomedullary albumin gradients, while they are administrated. The countercurrent exchange efficiency of the vasa recta is dependent on both the water and osmotic substance uptake out of the loops of Henle and the collecting ducts.
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  • 6
    ISSN: 1433-8580
    Keywords: Kidney ; Concentrating mechanism ; Corticomedullary gradients ; Urea ; Electrolytes ; Niere ; Konzentrierung ; Corticomedulläre Gradienten ; Harnstoff ; Elektrolyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An wachen, eiweißarm ernährten Wistar-Ratten wurde die Wirkung von Harnstoff auf die renale Wasserretention und Elektrolytkonzentrierung unter standardisierten Bedingungen (Trinkwasserentzug, mehrtägige kombinierte hypertone Harnstoff/NaCl-Infusion) untersucht. Die Ergebnisse lassen erkennen, daß Harnstoff aktiv aus den Sammelrohren resorbiert wird und daß Natrium bei Harnstoffzufuhr stärker im Nierenmarkgewebe angereichert wird als bei reiner Elektrolytinfusion. Die bei Harnstoffzufuhr erhöhten medullären Konzentrationen bewirken einen zunehmenden osmotischen Wasserentzug aus den Sammelrohren ins Interstitium. Die Harnvolumina nehmen bei Anstieg der Elektrolytkonzentrationen entsprechend ab. Es wird geschlossen, daß die wasserretinierende Wirkung des Harnstoffs am besten nachgewiesen werden kann, wenn — bei kalkulierter Wasser- und osmotischer Substanzzufuhr — die GFR konstant gehalten wird, weiterhin das Nephron hoch permeabel für Harnstoff ist, also bei maximalen medullären Natriumkonzentrationen und Harnstoff über längere Zeit bei gleichbleibender Konzentration infundiert wird.
    Notes: Summary Subject of the examinations was the special effect of urea to the renal water retention and electrolyte concentrating ability on protein lacking rats under standardized conditions (no drinking, long-term combined hypertonic urea/saline infusions). The results show, that urea is reabsorbed actively out of the collecting ducts and that sodium is better enriched in the renal medulla during simultaneous urea supply than with pure electrolyte infusion. These increased medullary concentrations cause an enlarged osmotic water removal out of the collecting ducts into the interstitium during urea supply so that the urine volumes decrease and the electrolytes are better concentrated in the urine. It is concluded, that the water retaining effect of urea could be proved best when the glomerular filtrates are kept unchanged, furthermore when the nephron is high permeable for urea, that is by maximal medullary sodium concentration, and when urea is infused by longterm supply in constant rations.
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  • 7
    ISSN: 1433-8580
    Keywords: Kidney ; Rat ; Ultrastructure ; Proximal tubule degeneration ; Heparinoid ; Niere ; Ratte ; Ultrastruktur ; Proximale Tubulusdegeneration ; Heparinoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 24 Std nach i.v. Injektion von 100 mg/kg eines Pentosanschwefelsäureesters (SP 54) sind in der Nierenrinde von Ratten schwere degenerative Veränderungen der proximalen Tubuluszellen zu beobachten. Das Tubulusepithel ist flachkubisch umgewandelt, das Tubuluslumen ist angefüllt mit ausgestoßenen Mitochondrien und anderen Zelltrümmern. Am stärksten betroffen ist die Pars contorta des proximalen Tubulus. Weniger stark veränderte Tubuluszellen sind angefüllt mit Cytosomen, die eine spezifische Feinstruktur haben oder gehäuft gegenüber Kontrollen Cytoplasmaprotrusionen in das Tubuluslumen aufweisen. Die akute Tubulusdegeneration ist ein spezifischer Effekt von SP 54. Heparin bewirkt nur eine leichte Schwellung des Tubulusepithels, die häufiger auftritt als bei Kontrolltieren.
    Notes: Summary 24 hrs after the intravenous injection of 100 mg/kg of a Pentosansulfuricacidester (SP 54) severe degenerative alterations are observed in the proximal tubular cells in rat kidney cortex. The tubular epithelium has changed to a single layer of elongated cubic cells. The tubular lumen is filled with cellular debris and extruded mitochondria. The greatest change is seen in the pars contorta of the proximal tubule. Less degenerated tubular cells have a great number of cytosomes with a specific substructure or have cytoplasmatic protrusions into the tubular lumen. This acute tubular degeneration is a specific event after the administration of SP 54 and is not seen after an equimolar dosis of Heparin. Heparin induces only a slight swelling of the tubular epithelium, more frequent seen as in the control animals.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 144 (1974), S. 173-186 
    ISSN: 1432-0568
    Keywords: Hippocampus ; Neurogenesis ; Autoradiography ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summay The prenatal ontogeny of the hippocampus, including the anterior continuation and induseum griseum, was examined in the rat by means of tritiated thymidine autoradiography. The neurons of the anterior continuation formed between the 16th and 18th days of embryonic development. The neurons of the induseum griseum were formed on the 16th and 17th days of gestation. The pyramidal cells of ammon's horn were formed during the 16th, 17th, 18th, and 19th days of embryogenesis but were preceded by the large interneurons of the stratum lacunosum-moleculare which formed on days 15 and 16 of embryonic life. The granule cells of the superficial layers of the stratum granulosum formed during the 20th, 21st, and 22nd days of gestation.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 143 (1974), S. 127-134 
    ISSN: 1432-0568
    Keywords: Reticular formation ; Crossed connections ; Autoradiography ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Injection of radioactive leucine in various regions of the brain stem reticular formation has revealed the presence of ample crossed reticulo-reticular connections in the cat. The terminal area for the crossed fibers are almost mirror images of the injected sites. The findings made is another example that hitherto unknown fiber connections can be demonstrated by axoplasmic protein tracing.
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  • 10
    ISSN: 1432-0568
    Keywords: Cerebellum ; Thalamus ; Electron microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An experimental electron microscopical study has been made on the mode of termination of the cerebellothalamic projections in the cat. Supporting experimental light microscopical studies of silver impregnated sections following a large lesion of the cerebellar nuclei and light microscopical autoradiographic studies of the thalamus following injections of tritiated leucine in parts of the cerebellar nuclei, have been made as well. Following large lesions of the cerebellar nuclei, only the largest occuring type of bouton in the cat's VL and VA (type LR bouton) degenerates. Following such lesions, type LR boutons undergo a filamentous hypertrophy before becoming electrondense. One degenerating LR bouton establishes complex synapses with the dendrites of both thalamocortical relay cells and interneurons. Not all type LR boutons in VL and VA degenerate following lesions of the cerebellar nuclei. Light microscopical autoradiographic studies as well as experimental electron microscopical investigations indicate that cerebellothalamic fibers end in clusters within VL and VA, and that the areas of termination lie more rostrally within these thalamic nuclei than has been inferred from experimental studies of silver impregnated sections following lesions of the cerebellar nuclei. The findings are discussed with respect to relevant morphological and physiological data.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 99 (1974), S. 255-263 
    ISSN: 1432-072X
    Keywords: Mannan Synthesis ; Saccharomyces cerevisiae ; Autoradiography ; Cell Wall ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The combination of high-resolution autoradiography and biochemical methods has been used to ascertain the site of mannan synthesis in the yeastSaccharomyces cerevisiae. High-resolution autoradiography has been performed under conditions when addedd-mannose-3H was incorporated exclusively into mannan. Application of “pulse-chase” labelling technique revealed that the radio-active mannose is fixed primarily in the cytoplasmic space from where it is transported into the cell wall. Additional experiments with separated membrane fractions from the same yeast strongly support the hypothesis that the plasmalemma is not directly involved in the biosynthesis of yeast mannan and that the membranes of the endoplasmic reticulum are the sites where the polymerization of mannosyl units takes place.
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  • 12
    ISSN: 1432-0827
    Keywords: Serum ; Calcium ; Phosphate ; Alkaline phosphatase ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract In 30 patients with chronic renal insufficiency (16 non-dialysed and 14 on dialysis) serum calcium, phosphate and alkaline phosphatase were determined and, in a crest biopsy specimen, morphometric determinations of bone qualities were calculated. A positive correlation was established between serum alkaline phosphatase, the osteoblast surface and the active resorption surface in both dialysed and non-dialysed patients. A positive correlation was also established between the osteoblast surface and the active resorption. In the non-dialysed patients a negative correlation was established between serum calcium and the osteoid surface.
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  • 13
    ISSN: 1434-4726
    Keywords: [3H]-GABA ; Cochlea ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Licht- und elektronenmikroskopisch wurde in Autoradiogrammen von der Cochlea und dem Gehirn des Meerschweinchens 1 Std nach3H-GABA an Hand der Silberkorndichte die Verteilung dieser Substanz untersucht. Nach intraarterieller Gabe fanden sich weder in der Cochlea noch im Gehirn Aktivitäten, woraus neben einer Blut-Hirn- auf eine Blut-Perilymphschranke geschlossen wird. Nach Perfusion der Cochlea bestand eine sehr hohe Markierung im Ganglion spirale. Abweichend zu anderen, tritium-markierten Aminosäuren waren3H-GABA-Aktivitäten nur über den Hüllzellen nachzuweisen, nicht über Ganglienzellen und Axonen. Die Bedeutung dieses Befundes ist ungeklärt. Im Cortischen Organ ließ sich lichtmikroskopisch eine selektive Markierung der efferenten Nervenfasern feststellen, zusätzlich erwiesen sich elektronenmikroskopisch nur efferente Synapsen markiert. Die meisten Silberkörner lagen über den Vesikeln und Mitochondrien, vereinzelte über dem Synapsenspalt. Die afferenten Synapsen blieben unmarkiert. Im Vergleich zu Literaturangaben über Lokalisation und Konzentration von GABA im Gehirn schließen wir auf einen hohen Gehalt an GABA im efferenten Innervationssystem des Cortischen Organs. Wegen bisher widersprüchlicher, elektrophysiologischer Ergebnisse kann aus der Verteilung allein nicht sicher auf eine Funktion dieser Substanz als Transmitter geschlossen werden.
    Notes: Summary In guinea pigs, 1 h after intraarterial and local administration of3H-GABA, autoradiographs of the cochlea and the brain were performed. As a parameter of distribution of this substance, silver grain density was examined by means of light and electron microscopy. Intraarterial injection was not followed by any activity neither in brain nor in the cochlea, an observation suggesting the existence of a blood-perilymph barrier additional to the blood-brain barrier. Perfusion of the cochlea produced a marked activity in the spiral ganglion. Different from other tritium labelled amino acids,3H-GABA activity could be found only in glia cells but not in nerve cell bodies or axons. The significance of this finding is open to question. In the organ of Corti a selective labelling of efferent nerve fibres could be found by means of light microscopy, additionally, using electron microscopy, only efferent synapses proved to be labelled. Most of silver grains were attached to vesicles and mitochondria, some grains to the synaptic cleft. Afferent synapses remained unlabelled. Comparing with publications concerning GABA localization and concentration in the brain, we conclude that the efferent system of the Organ of Corti contains a high concentration of GABA. As present electrophysiological results are contradictory the GABA distribution alone gives no convincing evidence that this substance may serve as a transmitter.
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  • 14
    ISSN: 1432-2013
    Keywords: Uric Acid Transport ; Hippurate Transport ; Organic Anions ; Kidney ; Liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Experiments were designed to determine whether renal excretion of uric acid is achieved by the same mechanism as for renal tubular excretion of hippurates and related organic acids. Surviving slices of rabbit kidney cortex were unable to accumulate C14-urate by a concentrative mechanism. Further, entry of C14-urate into renal slices was unaffected by acetate, probenecid or anoxia in accord with earlier observations from this laboratory with non-radioactive urate. Experience with isolated perfused rat liver supports the use of this experimental method as a model of the hippurate transport system. Unlike hippurate and a large number of related organic anions, neither urate nor C14-activity derived from urate was concentrated in the bile from this preparation. Probenecid did not inhibit excretion of the small amounts of C14-activity which did appear in the bile. Urate did not compete with indigo carmine, a nonmetabolizable substrate of the hippurate transport system, for excretion into the bile. From these findings, it is concluded that urate and organic acids such as hippurate do not behave similarly in kidney or in liver. The possibility that urate might be excreted by an independent active transport mechanism is not excluded. The demonstration that renal tissues can synthesize urate from hypoxanthine raises the possibility that urate synthesis might also occur in the intact animal and might contribute to the renal clearance of uric acid.
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  • 15
    ISSN: 1432-2013
    Keywords: Kidney ; Tubular Reabsorption ; Tubular Maximum ; $$P_{CO_2 } $$ ; Plasma [HCO 3 − ]
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Renal reabsorption of bicarbonate was examined in Merino ewes. In all experiments the bicarbonate reabsorption was directly related to that of sodium. When the rate of bicarbonate reabsorption was expressed as the ratio of bicarbonate over sodium reabsorption, no tubular maximum for bicarbonate could be demonstrated. Arterial pH or $$P_{CO_2 } $$ did not affect the reabsorption of bicarbonate except through alterations in the plasma bicarbonate concentration. The ratio of bicarbonate over sodium reabsorption was directly proportional to the plasma concentration of bicarbonate over a wide range. This evidence suggests that the ionic reabsorption of bicarbonate constitutes a major part of total bicarbonate reabsorption. It does not, however, exclude a contribution from an active hydrogen ion secretory process, as the kinetic properteis of such a process are as yet undetermined.
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  • 16
    ISSN: 1432-2013
    Keywords: Kidney ; ATPase ; Transport ; Cortex ; Medulla ; Papilla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The properties of microsomal ATPase were compared in the cortex, medulla and papilla of the rat kidney. 2. Activation of (Na+K)-dependent ATPase in the medulla was at lower potassium concentration than in the cortex or papilla. 3. (Na+K)-dependent ATPase in the papilla was more sensitive to ouabain than cortical or medullary ATPase. 4. (Na+K)-dependent ATPase in the kidney papilla was more sensitive to inhibition by calcium, cadmium andN-ethyl-maleimide than the enzyme from the kidney cortex or medulla. 5. Mg-ATPase in each region of the kidney was more resistant to inhibition by calcium, cadmium orN-ethyl-maleimide than the corresponding (Na+K)-dependent activity. 6. Mg-ATPase in the papilla was more resistant to inhibition by these inhibitors as well as by thiocyanate than the enzyme from cortex or medulla. 7. These data may suggest functional differences in the microsomal ATPase of various regions in the kidney.
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  • 17
    ISSN: 1432-2013
    Keywords: Kidney ; Renal Blood Flow ; Acute Renal Failure ; Renal Resistance ; Clearance Techniques ; Renal Venous Outflow ; Temporary Ischemia of the Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Total renal blood flow (RBF-dir) and total renal resistance were determined in acutely uninephrectomized rats by measuring the renal venous outflow after catheterizing the renal vein. Renal vein catheterization and the procedure involved caused an initial fall in C-IN and C-PAH followed by a steady level over an experimental period of 2–3 h. Absolute and fractional water excretion increased approx. 9-fold during that time. Mean RBF-dir was 14.2±0.67 (N=13) ml/min×kg BW×1 kidney. In another series of animals acute renal damage was induced by subjecting the kidneys to a 60 min period of temporary ischemia 3 days prior to use. RBF-dir decreased 10%, total renal resistance increased 11%, neither parameter being significantly different from controls. The clearance of inulin and PAH, the extraction ratio of PAH, and the urine flow rate were depressed to about 10% of control (P〈0.001). A considerable discrepancy was found between data obtained by clearance methods and RBF-dir after ischemia: The ratio RPF-PAH/RPF-dir was 1.05 under control conditions and was significantly depressed to 0.47 (P〈0.005) after ischemia.—These results indicate that a general increase in resistance of the vasa afferentia alone cannot be responsible for the oliguric phase. At least two important factors are involved in the cause of oliguria 3 days after temporary ischemia: Backdiffusion of tubular fluid through the damaged tubular epithelium and a decrease in GFR.—Clearance methods are not considered to be reliable determinants of GFR and RPF in renal failure after temporary ischemia.
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  • 18
    ISSN: 1432-2013
    Keywords: Cerebellum ; Proline ; Transmitter ; Iontophoresis ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Iontophoretic experiments with the aid of multibarreled micropipettes demonstrate a reversible depressant effect ofl-proline on the spontaneous discharge of Purkinje cells in the cat cerebellar cortex. The failure of a specific interaction with strychnine and bicuculline leads to the conclusion that proline acts neither on receptors for “glycine-like” nor on receptors for “GABA-like” amino acids. Autoradiographic investigations reveal a differential distribution of radioactivity after injection of3H-leucine and3H-proline into the cerebellar cortex. After leucine injection, high grain density can be observed over Stellate, Basket, Golgi and especially Purkinje cells. In contrast after application of3H-proline, the silver grains are concentrated primarily in the tissue adjacent to the Purkinje cells, mainly in the supraganglionic region and between these faintly labelled cerebellar cells. These results suggest the possibility that proline is involved in inhibitory neurotransmission.
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  • 19
    ISSN: 1432-2013
    Keywords: Paracellular Shunt Pathway ; Transtubular Permeability ; Perfused Toad Kidney ; Transtubular Osmotic Gradient ; Kidney ; Epithelia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Trace amounts of either labelled mannitol, sucrose, raffinose or inulin were added to the portal circulation in the doubly perfused toad kidney and their-urine-to-portal fluid, labelled molecules-to-chemical inulin ratio (denoted here asR) was evaluated. Under control isosmotic conditionsR was found to be inversely related to the probing molecule radius.R for inulin was practically zero.R for all probing molecules rose reversibly when the luminal fluid was rendered hyperosmotic by addition of 50 mmole mannitol to the aortic circulation, and even more so when 50 mmole urea was added per liter of aortic fluid. ThusR for raffinose rose from 0.0025±0.0002 (control) to 0.0126±0.0012 (+50 mM mannitol) and to 0.0967±0.0112 (+50 mM urea). This increase inR must be due to widening of the paracellular shunt pathway since the contribution of portal circulation to the glomerular filtrate was negligible and these molecules are known to stay extracellular. The present experiments suggest that transtubular urea (and osmotic) gradients may play a role in the regulation of the size of the paracellular shunt pathway.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric radiology 2 (1974), S. 39-41 
    ISSN: 1432-1998
    Keywords: Kidney ; blood flow ; circulation time ; reflux ; pyelonephritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The intrarenal circulation time in rabbits was found to decrease when the intrapelvic pressure was elevated acutely. A possible explanation is a redistribution of the blood flow with part of the blood effectively by-passing some renal parenchyma and thereby hypothetically resulting in local ischaemia. At vesico-ureteral reflux the same mechanism may cause repeated episodes of ischaemia. This may well happen particularly in areas drained by a damaged papilla, where rises in the intra-pelvic pressure may be conducted directly into tubuli and peritubular capillaries and veins.
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  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 351 (1974), S. 323-330 
    ISSN: 1432-2013
    Keywords: Uricase ; Urate ; Allantoin ; Liver ; Kidney ; Microperfusion ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. In vivo uricase activity was tested in rats by injection of 2-C14 urate and measurement of the total C14 activity and the fractional activities of allantoin, allantoic acid and urea in samples of blood and urine. In control animals, 5 min after the injection, 70% of the plasma tracer was already present in the form of allantoin. No allantoic acid and urea were produced. Intestinectomy had no measurable influence on uricase activity. On the other hand, hepatectomy or ligation of the hepatic artery combined with subtotal viscerectomy did abolish uricase activity almost completely. 2. Following microinjections into proximal tubules of Ringer solution containing 2-C14 urate, urine samples during early recovery mainly contained labelled urate, whereas in later samples the fraction of labelled allantoin increased. About 12 min after the microinjection the urine of both kidneys contained equal amounts of tracer mainly in the form of allantoin. 3. When segments of proximal tubules were perfused with an equilibrium solution containing tracer amounts of C 14 urate, no urate was metabolized during its passage through the proximal tubule. 4. C 14 urate was offered from the peritubular capillaries and samples of tubular fluid were analyzed, Again, all the tracer in the tubular fluid was in the form of urate, indicating that urate is not oxidized when it is transported across the tubular cell. It is concluded from these results that: 1. The rat kidney has no significant uricase activity. 2. Urate transport in the kidney is not influenced by this enzyme. 3. The degradation of urate to allantoin takes place at extrarenal sites, mainly in the liver.
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  • 22
    ISSN: 1432-0878
    Keywords: Kidney ; Sexual segment ; Natrix natrix ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sexual segment of the kidney of Natrix natrix has been investigated cytochemically, light microscopically and ultrastructurally. The sexual segment, which seems to be an important accessory sexual organ, has a single layer of a columnar epithelium. The epithelial cells are filled with large secretion granules of a wide range of electron densities. Cytochemical reactions for neutral and acid mucosubstances are negative, but the cells show a strong positive staining for phospholipids. Within the cells of the sexual segment we have localised by histochemical means several hydrolases and oxydoreductases, which reflect enzyme activities of the glycolytic pathway, the citrate cycle, and related metabolic pathways. The activities of the hydrolytic enzymes acid phosphatase, acetylcholinesterase and indoxylacetate esterase are remarkably high within the epithelial cells. Furthermore it was found that the sexual segment tubules possess contractile elements which extends over the basal surface of the epithelial cells. These contractile cells exhibit a very high activity of alkaline phosphatase. Single unmyelinated axons are located between the contractile elements and the basal lamina of the sexual segment cells. The functional significance of the sexual segment structures is briefly discussed.
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  • 23
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Frog ; Ultrastructure ; Intracellular transport ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The route by which secretory proteins are transported in the frog exocrine pancreas cell was investigated by an ultrastructural and electron microscope autoradiographic analysis of in vivo 3H-leucine labelled tissue. The ultrastructure of the cell is characteristic of serous epithelial cells and resembles that of mammalian exocrine pancreas cells very closely. Autoradiographic results revealed that the proteins, after being synthesized in the rough endoplasmic reticulum (RER), are transported through the Golgi cisternae to condensing vacuoles which subsequently change into secretory granules. The determination of the timing of this transport was complicated by a very slow turnover of leucine in the frog. Nevertheless, by a semi-quantitative approach, some time characteristics could be estimated: about 11 min after the onset of their synthesis the proteins enter the Golgi system, and about 25 min later the condensing vacuoles. Secretory granules become labelled between 60 and 120 min. These results are discussed, also in relation to the transport route and kinetics in mammalian tissue.
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  • 24
    ISSN: 1432-0878
    Keywords: Retinal projections ; (Tupaia glis) ; Axonal transport ; Synapse ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Retinal projections were studied in the tree shrew, Tupaia glis, by means of thaw-mount autoradiography. In this technique, unfixed and unembedded frozen sections are directly mounted on photographic emulsion coated slides. Loss of radiolabeled material through tissue processing is avoided, probably resulting in increased discriminatory sensitivity. Together with multiple injections of precursor cocktail it is possible to demonstrate at the light microscopic level (1) fibers in passage and axon terminals simultaneously, and (2) preferentially labeled axon terminals in the projection field as areas of greater grain density.
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  • 25
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Mitochondria ; ACTH ; DNA-synthesis ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a chronic ACTH administration (up to 12 consecutive days) on the 3H-thymidine uptake by the mitochondrial compartment of rat adrenal zona fasciculata were investigated by high resolution autoradiography, and compared with the changes in volume and number per cell of these organelles induced by the hormonal treatment. Up to the 9th day of treatment there is a significant increase in the tracer incorporation into adrenocortical mitochondria which is coupled with a significant increase in the volume of the organelles. After 12 days of hormone administration a significant decrease in the 3H-thymidine mitochondrial uptake is found, which is associated with a conspicuous increase in the number of mitochondria per cell and a net decrease in their average volume. The data are discussed in the light of evidence indicating that mitochondria possess a genetic apparatus largely independent of nuclear control. It is hypothesized that ACTH controls the growth and proliferation of adrenocortical mitochondria and that the mechanism of this action of ACTH involves stimulation of the mitochondrial DNA synthesis.
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  • 26
    ISSN: 1432-0878
    Keywords: Ventricle ; Tanycytes ; Monoamine transport ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This investigation has dealt with a light and electron microscopic autoradiographic analysis of the median eminence of the rat following intraventricular infusion of 3H-dopamine. This study has demonstrated that 3H-dopamine, once infused into the mammalian cerebral ventricular system, is rapidly and selectively absorbed by tanycytes and transported to the contact zone within 5 minutes after ventricular infusion. Certain axon terminals in the ependymal, hypendymal, and palisade-contact zones selectively sequester 3H-dopamine as do subpopulations of arcuate neurons. This picture of intense labelling of neurons and axon terminals is discussed with respect to monoaminergic re-uptake mechanisms. Uptake and transport of 3H-DA by tanycytes is discussed.
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  • 27
    ISSN: 1432-0878
    Keywords: Oocytes and T-prospermatogonia ; Rat ; Quantitative analysis ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Bei der Ratte findet die sexuelle Differenzierung der Gonade zwischen dem 14. und 15. Tag post conceptionem (p.c.) statt. Während dieser Zeit teilen sich die Oogonien und deren Parallelpopulation—die M-prospermatogonien (multiplying prospermatogonia) oder I-Gonocyten—sehr häufig. Um den 17. Tag p.c. tritt die letzte Generation der Oogonien bzw. der M-prospermatogonien in die Mitose. Die Mitosen bilden häufig “synchronisierte Gruppen”. Die postmitotischen Kerne ihrer Tochterzellen—der Oocyten und der T 1 prospermatogonien (primary transitional prospermatogonia) oder II-Gonocyten—sind klein. Ihr Chromatin ist in Form gröberer Schollen der Kernmembran angelagert. Auf diese Weise kommt das typische “krustenförmige” Aussehen bzw. die Ähnlichkeit mit den Prophasen der Oogonien und M-prospermatogonien zustande. Die Oocyten durchlaufen zunächst die G1-phase (etwa 10 Std Dauer) und treten dann—am Ende des Präleptotänstadiums—in die S-phase. Dann passieren sie die verschiedenen Stadien der meiotischen Prophase und treten vom 3. Tag post partum (p.p.) ab in das Dictyotänstadium. Die T1-prospermatogonien hingegen befinden sich etwa 10 Tage lang in der G1-phase, ohne wesentliche morphologische Veränderungen aufzuweisen. Vom 4. Tag p.p. an durchlaufen sie die S-Phase. Die S-Phasen-Dauer (D-S) beider Zellarten beträgt 11.5 Std und wurde durch Doppelmarkierung mit 14C- und 3H-Thymidin bestimmt. Als am besten geeignete Termine für die Bestimmung der D-S erwiesen sich bei den Oocyten der 18. Tag p.c. und bei den T1-prospermatogonien der 5. Tag p.p. Zu diesen beiden Zeitpunkten war die Anzahl der in die S-phase ein-und austretenden Oocyten bzw. T1-prospermatogonien gleich, die Zellen in S-phase befanden sich im “steady state”. Das Kernvolumen der Oogonien und M-prospermatogonien ist etwa doppelt so groß wie das der postmitotischen Oocyten und T1-prospermatogonien. Bis zum 5. Tage p.p. nimmt das Kernvolumen der Oocyten und T1-prospermatogonien um etwa das Fünffache zu. Der Degenerationsindex der Oocyten liegt wesentlich höher als der der T1-prospermatogonien; er ist postnatal besonders hoch. Aus den T1-prospermatogonien gehen am 4. und 5. Tage p.p. durch Teilung die T 2-prospermatogonien (secondary transitional prospermatogonia) hervor. Die Kerne dieses Zelltyps sind etwas kleiner also die der T1-prospermatogonien. Die T2-prospermatogonien treten am 6. Tage p.p. in die Mitose; es entstehen die ersten A-spermatogonien.
    Notes: Summary In the rat (Wistar-WU) sexual differentiation of the gonads occurs between days 14 and 15 post conception (p.c.). At this time the oogonia and their parallel population — the M-prospermatogonia (I-gonocytes)—divide rapidly. On about day 17 p.c., the last generation of oogonia and M-prospermatogonia, frequently arranged in synchronized clusters, enters mitosis. The postmitotic nuclei of their daughter cells—oocytes and T 1-prospermatogonia (II-gonocytes)—are small; coarse flakes of chromatin are associated with the nuclear membrane causing the typical “crustlike” appearance and the similarity with the prophases of oogonia and M-prospermatogonia. After the oocytes have passed a G1-phase of approximately 10 hr, they enter the S-phase at the end of the preleptotene stage. Then they pass the different stages of the meiotic prophase until they enter the dictyate stage from 3 day post partum (p.p.) onwards. The T1-prospermatogonia, on the other hand, spend a long G1-phase of about 10 days without any conspicuous morphological change before entering the S-phase from day 4 p.p. onwards. The duration of the S-pbase (D-S) of both cell types—oocytes and T1-prospermatogonia—as determined by the double labeling method with 14C- and 3H-thymidine is found to be 11.5 hr. The most favourable time for determining the D-S was day 18 p.c. for the oocytes and day 5 p.p. for the T1-prospermatogonia. On these two days the balance was reached between the cells entering and leaving the S-phase. The nuclear volumes of the postmitotic oocytes and T1-prospermatogonia are approximately half the size of those of their precursors. Until day 5 p.p. the nuclear volumes of the oocytes and T1-prospermatogonia increase about fivefold. The degeneration index of the oocytes is considerably higher than that of the T1-prospermatogonia; postnatally it is especially high. T 2 prospermatogonia arise by mitosis of the T1-prospermatogonia on day 4 and 5 p.p. The nuclei of this cell type are smaller than those of T1-prospermatogonia. T2-prospermatogonia enter mitosis on day 6 p.p and give rise to A-spermatogonia.
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  • 28
    ISSN: 1432-0878
    Keywords: 3H-γ-aminobutyric acid uptake ; Visual system ; Lamina ganglionaris ; Musca, Drosophila ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The uptake of 3H-GABA in the visual system of half-head preparations of Musca and Drosophila was studied by means of light and electron microscope autoradiography. Of all three ganglia, only the first synaptic region, the lamina ganglionaris, showed accumulation of radioactive grains, and there a preferential glial uptake could be found. Under normal light conditions at incubation (constant light flux of 100 Lux) the maximum of radio-activity was found in the marginal glia cells. Increasing the time of incubation produced also an increase in the number of grains per surface unit in the marginal glia cells. After changing the light intensity during incubation, quantitative modifications of the distribution of radio-activity were observed: incubating with stroboscopic illumination, the number of grains diminished in the marginal glia cells and remained constant in the epithelial cells; incubated in darkness, the epithelial cells became more intensely labelled whilst the number of grains decreased in the marginal cells. The possibility is discussed that the receptor axons 1–6 are the neurological elements of the lamina which use GABA as a transmitter. This hypothesis is lent some support from results of similar experiments with neurological mutants of Drosophila. In opm 18 there was a delayed uptake of 3H-GABA whereas in opm 3 and ebony the results were comparable to those found in Musca incubated in darkness. Behavioral studies on these mutants have demonstrated a defect, most probably related to the receptor system 1–6.
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  • 29
    ISSN: 1432-0878
    Keywords: Proline ; Keratohyalin ; Basal lamina ; Epithelium ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mouse lingual epithelium incorporates significant amounts of L-proline-2, 3-H3 one hour after intraperitoneal injection of the tritiated amino acid. All viable cell strata incorporated approximately equal amounts of proline as assessed by autoradiographic techniques. Grain counts at 30 minutes, 1 hour, 4 hours and 24 hours, the four time periods studied, indicated a progressive incorporation of proline up to 4 hours following injection. Preferential incorporation of proline into any one cell structure or group of structures was not observed. Keratohyalin granules (KHG's) demonstrated incorporated proline; however, usually only one silver grain appeared over each granule, and, based on grain counts, the amount of proline incorporated by KHG's appeared slightly less than the general labeling observed in KHG-containing cells. This finding supports recent biochemical studies which have indicated a considerably lower proline content of keratohyalin than had previously been reported. Significant proline incorporation into the epithelial basal lamina was not observed during the 24 hours of this study. Thus, while recent recombination experiments have conclusively demonstrated that epithelial basal cells synthesize considerable quantities of basal lamina in a 24 hour period; it would appear that epithelial basal cells contribute little to a formed, intact basal lamina. This finding lends credence to the concept of a long basal lamina turnover time.
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  • 30
    ISSN: 1432-0878
    Keywords: Haematopoiesis ; Lymnaea stagnalis ; Amoebocytes ; Autoradiography ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to investigate haematopoiesis in the freshwater pulmonate Lymnaea stagnalis, the blood cells and the connective tissue of this snail were studied by light and electron microscopy as well as by autoradiography. In the circulating blood only one type of cell, the amoebocyte, is present. Amoebocytes also occur in the connective tissue (tissue amoebocytes) as single cells, in small groups or in large accumulations. Study of the morphology and ultrastructure of blood and tissue amoebocytes shows that no differences exist between these cells, indicating that L. stagnalis does not possess a well-defined haematopoietic organ. This assumption is supported by the following observations: 1. both blood and tissue amoebocytes can act as phagocytes, 2. blood and tissue amoebocytes both have the capacity to divide (i.e. incorporate tritiated thymidine) and 3. the percentage of dividing cells in the blood and in the connective tissue is the same. These quantitative data indicate furthermore that there is no difference in the relative importance of the blood and the connective tissue in the process of haematopoiesis. Comparison of tritiated thymidine labelled cells with unlabelled amoebocytes showed that these cells do not differ with respect to their morphology and ultrastructure. Moreover, amoebocytes involved in phagocytosis and encapsulation of foreign materials or in wound healing still have the capacity to divide. The percentages of tritiated thymidine labelled amoebocytes in different snails varied considerably. It is suggested that this variation reflects differences in the physiological state of the individual snails.
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  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 153 (1974), S. 399-413 
    ISSN: 1432-0878
    Keywords: Spinal ganglia (Rat) ; Cell division ; Autoradiography ; Neurone morphogenesis ; Light and electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pulse labelling with tritiated thymidine was used to determine the time of the final division of the neuroblasts which subsequently form rat lumbar dorsal root ganglion neurones. The final division occurred during a 4 day period, the maximum frequency being on day 12 of gestation. Separation of the ganglion cells into large light neurones and small dark neurones showed that the large light neurones were formed earlier than the small dark neurones. In both cases the final divisions occurred over a period of 3–4 days, but the peak rate of formation of large neurones was on day 12, and that of the small neurones was on day 13. Low power electron micrographs were used to measure mean cell diameter throughout development from day 11 of gestation until a postnatal age of 225 days. A marked increase in cell diameter occurred on day 15–15.5, about 3 days after the final cell divisions of the majority of the cells. The rate of growth increased just before birth, but no increase in mean cell diameter was found between day 21 of gestation and the third day postnatal. The growth was again rapid after this period until a plateau in cell diameter was reached about 33 days after birth.
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  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 147 (1974), S. 183-190 
    ISSN: 1432-0878
    Keywords: Kidney ; Rat ; Bowman's capsule ; Experimental hypertension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The parietal layer of Bowman's capsule was examined in the rat in control animals and in animals made hypertensive by treatment with desoxycorticosterone acetatesaline and by clipping of the renal artery. At an early stage of elevation of blood pressure and, occasionally, prior to elevation of blood pressure, the epithelial cells of this layer showed basal cytoplasmic protrusion and reduplication accompanied by an increase in the thickness of the basement membrane. These changes preceded evidence of glomerular or renal arteriolar pathology. They presumably reflect either a response of this layer to increased blood pressure and modified glomerular function, or a direct effect of the factors that also induces blood pressure elevation. In either case, they imply a greater functional significance for the parietal layer than has usually been attributed to it.
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  • 33
    ISSN: 1432-0878
    Keywords: Sea anemone mesoglea ; Collagen synthesis ; Epitheliomuscular cells ; Electron microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy and autoradiography (H3-proline) were used to determine the cell(s) responsible for collagen synthesis and lamination in the mesoglea of the sea anemone, Aiptasia diaphana. Mesogleal collagen is synthesized by the epidermal epitheliomuscular cells which contain much rough endoplasmic reticulum, and secretory vesicles attached to microtubules which cross the basal plasmalemma and anchor in the basement membrane; these cells incorporate large amounts of H3-proline. The mesogleal collagen fibers are non-striated, have clear centers, and a diameter of 200–260 Å; their walls are composed of 65 Å diameter subunit fibrils which appear to be helically oriented. Epitheliomuscular cells rest upon a subepidermal basement membrane which is composed of mesogleal collagen fibers, 65 Å subunit fibrils, and dense granules. This subepidermal basement membrane labels definitively with H3-proline, and is the region where soluble collagen precursors apparently form subunit fibrils which associate to yield mesogleal fibers. The columnar mesogleal collagen fibers are arranged to form layers: the fibers of each layer have the same longitudinal orientation, while those of adjacent layers display an approximate orthogonal arrangement. It is felt that the subepidermal basement membrane is responsible for this organization of mesogleal fibers. Mesogleal amoebocytes do not label with H3-proline and show no ultrastructural evidence of collagen secretion.
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  • 34
    ISSN: 1432-0878
    Keywords: Hypothalamic neurosecretory system (rat) ; Adrenal cortex ; 35S-cysteine incorporation ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The incorporation of 35S-labelled cysteine in the hypothalamic-neurohypophyseal system was studied in normal and adrenalectomized rats and in rats treated with excess hydrocortisone. Labelled cysteine was intraperitoneally administered and grain counts were made of autoradiographs produced from sections of the supraoptic and paraventricular nucleus, median eminence and neurohypophysis of animals killed 45 min., 4 hours and 24 hours after administration of the labelled substance. On the whole, lower incorporation levels of the label were noted in the adrenalectomized rats, compared with the controls. In the rats treated with excess hydrocortisone, the grain counts at 45 min and 4 hours after injection were higher and those at 24 hours were lower than those of the controls. The findings are discussed, among other things, in terms of rate of uptake vs. time and related to previous reports on the cysteine uptake and neurosecretory activity of the hypothalamic-neurosecretory sytem.
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  • 35
    ISSN: 1432-0878
    Keywords: Post-capillary venules ; Mice ; Pathway of B lymphocytes ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histological observation on the mesenteric lymph node and Peyer's patches of C3H B mice, neonatally thymectomized, lethally irradiated and reconstituted with syngeneic bone marrow cells, showed that a large number of lymphocytes appeared selectively in the restricted territory surrounding the post-capillary venules. Severe depletion of lymphocytes persisted in most of the thymus-dependent areas. Lymphocytes were also observed passing through the walls of the post-capillary venules. Autoradiographic studies on the mesenteric lymph node of recipient B mice 30 minutes after intravenous injection of cells labelled with 3H-uridine and taken from lymph nodes of donor B mice showed that B lymphocytes could penetrate the walls of the post-capillary venules from the blood into the peripheral lymphoid tissues. The post-capillary venules, which are known as the recirculating route of T lymphocytes in normal animals, are thought to be the pathway of migrating B lymphocytes in B mice.
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  • 36
    ISSN: 1432-0878
    Keywords: Encapsulation ; Lymnaea stagnalis ; Amoebocytes ; Cell transformation ; Cellular defence mechanism ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The encapsulation of experimentally introduced material was studied in Lymnaea stagnalis. Abiotic (yvelon sponge) and biotic materials (autografts, allografts and xenografts) were implanted into the cephalopedal blood sinus. Within 24 hrs the yvelon sponge is completely invaded and encapsulated by round amoebocytes. Amoebocytes are the only type of blood cell in L. stagnalis. The number of capsule amoebocytes increases until 3 days after implantation. These capsule amoebocytes are normal blood amoebocytes. This inclusion is based on morphological observations as well as on the results of labelling experiments (blood amoebocytes were labelled with India ink or 3H-thymidine). These data are in accordance with evidence that amoebocytes may have more than one function. From 24 hrs onwards a progressive flattening of the capsule amoebocytes was observed. In 7-day-old capsules 3 strata were distinguished: inner and outer strata consisting of tightly packed, flattened amoebocytes, and a middle stratum still composed of round amoebocytes. The cells of the outer stratum possess an extensive granular endoplasmic reticulum. During the further process of encapsulation the cells of the inner stratum become loaded with lysosomes. The middle stratum disappears: the cells flatten and become part of the other two strata. In the outer stratum, collagenous connective tissue fibrils and ground substance are deposited between the cells. This situation is reached about 1 month after implantation. Capsule formation is completed by that time: during the next 5 months, no major structural changes occur in the capsules. The reactions to biotic materials appeared to be quite different, and show that L. stagnalis is able to discriminate between different types of graft. Autografts and allografts are not encapsulated—only a transient amoebocyte reaction occurs at the cut surfaces of the transplants—whereas xenografts evoke a severe host reaction: they are infiltrated and encapsulated by amoebocytes. It is suggested that the discrimination mechanism is located in the plasma membrane of the amoebocytes. The encapsulation of xenografts ends in a capsule consisting only of the collagenous connective tissue stratum. The cells of the inner stratum infiltrate the graft and phagocytose degenerated graft tissue. Autoradiographic experiments using 3H-proline as a marker for collagen synthesis showed that the flattened cells of the outer stratum produce collagenous connective tissue fibrils, indicating that these cells are fibroblasts. In experiments using ink or 3H-thymidine labelled amoebocytes it was shown that these fibroblasts are transformed amoebocytes. Finally it is suggested that amoebocytes also have the capacity to transform into myofibroblasts.
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  • 37
    ISSN: 1432-1912
    Keywords: Kidney ; Adrenaline ; Catechol-O-methyltransferase (COMT) ; Inhibition ; H22/54 [(±)-α-Dihydroxyphenyl]-n-valeramid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the dog kidney catecholamines are O-methylated before being secreted by the tubule (Hempel et al., 1973). Adrenaline was used in an investigation to determine whether or not O-methylation is a prerequisite for the tubular secretion of a catecholamine in the dog. In dogs (n=3) treated with the COMT inhibitor H22/54 [(±)-α-(3,4-dihydroxyphenyl)-n-valeramid] the excretion of 14C-(±)-adrenaline and the pattern 14C-adrenaline metabolites in urine were measured. 14C-adrenaline (9.2 μg per injection) was injected simultaneously with 3H-inulin into both renal arteries. Eigth injections of radioactive material were given to each animal. COMT was inhibited before the second 14C-adrenaline injection by infusion of H22/54 into the left renal artery in doses of 0.16, 0.72 and 3.2 mg/kg b.w., respectively. Without H22/54 the injected dose of 14C-adrenaline was excreted by the kidney within 12 min as followed: 22.2 ± 6.0% (n=6) as 14C-adrenaline, 21.8 ± 7.0% (n=7) as 14C-metanephrine, and 9.3 ± 2.2% (n=7) as deaminated or conjugated 14C-adrenaline metabolites. H22/54 reduced the excretion of 14C-metanephrine to 9–28.2% of the control value, whereas the 14C-adrenaline excretion was considerably increased, up to 200% of the control. It is concluded that the additional 14C-adrenaline observed in urine after COMT inhibition was secreted by the tubule. Thus, O-methylation seems not to be a prerequisite for tubular secretion of adrenaline in the dog.
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  • 38
    ISSN: 1432-1912
    Keywords: 3H-Chlorphentermine ; Autoradiography ; Secreting Tissues ; Reticulo-Endothelial System ; Phospholipids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 3H-Chlorphentermine is selectively taken up by secreting tissues, the reticulo-endothelial and lymphatic system and other lipid-rich organs, like central nervous system, retina and lungs. Considerable amounts are still present at least 1 week after a single i.v. injection. The extensive binding of chlorphentermine in these lipid-or phospholipid-rich organs is probably due to strong complex formation between this drug and phospholipids. Comparison of this distribution pattern with that of other amphiphilic drugs of related structure (halogenated aralkylamines) suggests that a general mechanism might be involved in the observation reported.
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  • 39
    ISSN: 1435-2451
    Keywords: Kidney ; Organ Preservation ; Transplantation ; Niere ; Organkonservierung ; Transplantation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Nierentransplantation ist eine wesentliche Ergänzung der Dauerdialysebehandlung geworden. In der Bundesrepublik Deutschland ist die Transplantationsfrequenz jedoch sehr niedrig. Dies ist enter anderem auf den Mangel an Spenderorganen zurückzuführen. Die Ausstellung hatte zum Ziel, die Methodik der Organentnahme und der Organkonservierung Bowie die notwendigen organisatorischen Maßnahmen aufzuzeigen. Die in der BRD aktiven Transplantationszentren wurden aufgeführt, um die Beteiligung anderer Kliniken an der Transplantationschirurgie anzuregen.
    Notes: Summary Kidney transplantation is an essential complement to chronic dialysis, but the frequency of transplantation is very low in the Federal Republic of Germany. One reason is the shortage of donor organs. The exhibition demonstrates the method of organ exstirpation and preservation of the organs as well as describing the necessary administrative measures: A list of the transplantation centres in the Federal Republic of Germany is given to encourage other clinics to become involved in kidney transplant operations.
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  • 40
    ISSN: 1432-1076
    Keywords: Autoradiography ; Whole-body autoradiography ; Stripping-film technique ; 14C-bilirubin ; Phenobarbital ; Gunn rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Autoradiographie mit 14C-Bilirubin bei trächtigen normalen Wistarratten und Gunnratten mit und ohne Phenobarbital-oder Albumingabe. Trächtige normale Wistarratten und Gunnratten erhielten 25 μCi (1 mg) 14C-Bilirubin i.v. Sie wurden zu verschiedenen Zeiten getötet. Mit Hilfe der Ganztierautoradiographie konnten die verschiedenen Stoffwechselwege des Bilirubins bei normalen und Gunnratten studiert werden. In dem der Leber entsprechenden Areal der Autoradiogramme waren bei normalen Ratten zahlreiche intensive Schwärzungspunkte sichtbar, d. h., es war zu einer biliären Ausscheidung des verabreichten Isotops gekommen, andererseits wies das Autoradiogramm der Gunnrattenleber eine mehr diffuse Schwärzung auf. Der Darm der normalen Ratten war schon kurz nach der Injektion mit dem Isotop angefüllt, während bei Gunnratten das Darmlumen frei von Radioaktivität blieb, jedoch fand sich eine größere Isotopenmenge in der Darmwand, was auf eine Bilirubinausscheidung über die Darmschleimhaut hinweist. Der Isotopengehalt der Nierenrinde war bei allen Tieren etwas höher als der des Nierenmarks. Darüber hinaus zeigten die Nierenpapillen bei Gunnratten eine sehr hohe Aktivität — hier findet eine Auskristallisation des Bilirubins statt. Im Gehirn und im Rückenmark war gewöhnlich keine Radioaktivität außerhalb der Blutbahn nachweisbar. Nur bei einer Gunnratte, bei der unmittelbar nach der Bilirubininjektion vorübergehend eine Apnoe auftrat, waren Isotopenablagerungen in der Gehirnsubstanz vorhanden. Die Radioaktivität in den Feten der normalen und Gunnratten war geringer als die im Muttertier. Das Darmlumen der Feten war stets frei von Radioaktivität, und zwar auch bei Feten von normalen Wistarratten, die selbst große Isotopenmengen im Darm aufwiesen. Mit Hilfe der sogenannten Stripping-Film-Methode konnte gezeigt werden, daß schon 30 sec nach der Injektion eine gewisse Isotopenmenge in die Leberzelle aufgenommen worden war. Nur bei normalen Wistarratten fand sich in späteren Stadien des Versuchs in den Gallencapillaren und intrahepatischen Gallengängen eine deutliche Radioaktivität. Durch gleichzeitige Injektion von 14C-Bilirubin und Albumin änderte sich nichts an dem autoradiographischen Befund. Auch eine Phenobarbital-Vorbehandlung hatte keinen Einfluß auf das Ergebnis der Autoradiographie.
    Notes: Abstract Pregnant normal Wistar rats and Gunn rats were given 25 μCi (1 mg) 14C-bilirubin intravenously. They were killed at different intervals. Whole-body autoradiography was used to study the different pathways of bilirubin in normal rats and in Gunn rats. Numerous spots of intense blackening were seen on the autoradiographs in the area of the liver of normal rats, indicating biliary excretion of the administered isotope. In the autoradiographic picture of the Gunn rat liver more diffuse blackening was present. In the normal rat the bowels contained radioactive material shortly after the injection, whereas in Gunn rats no radioactivity was demonstrable within the lumen of the bowels; the area over the bowel wall showed intense staining suggesting some mucosal excretion of bilirubin, however. The isotope content of the renal cortex was somewhat higher than that of the medulla in all animals. In addition, the papillae of the Gunn rat kidney contained a very high level of radioactivity; crystallization of bilirubin takes place in this area. Usually there was no radioactivity in the brain or spinal cord outside the vessels. One Gunn rat with an apneic spell immediately after the injection of bilirubin has isotope deposits throughout the brain. The fetuses of normal and Gunn rats showed less radioactivity than the mother animals. The lumen of the fetal bowels was always free of radioactivity even in fetuses of normal Wistar rat mothers with large amounts of the isotope within the gut. With the aid of the stripping-film technique it was possible to demonstrate that some isotope was localized within the liver cell as soon as 30 sec after the injection. In normal Wistar rats only an intense blackening was visible over the bile capillaries and intrahepatic bile ducts in later stages of the experiments. If albumin was given in addition to 14C-bilirubin the same autoradiographic pattern was obtained. Phenobarbital pretreatment caused no autoradiographic changes.
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  • 41
    ISSN: 1432-1106
    Keywords: 6-Hydroxydopamine ; Neuronal uptake ; Central nervous system ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tritiated 6-hydroxydopamine (6-OHDA) was injected into the lateral ventricle of rats and rabbits and visualized by means of autoradiography. In unfixed frozen sections, radioactive material was found penetrating about 2 mm into the periventricular tissue within 4–48 hours after injection. Radioactivity was localized preferably in particular nuclei, leaving the fiber bundles nearly free of label. In formalin-fixed paraplast-embedded sections the appearance of silver grain clusters was the very characteristic finding representing most probably uptake into presynaptic terminals. Labelling pattern suggests highly selective uptake of 6-OHDA by terminals of noradrenaline and dopamine-containing neurones; also a few single neurones of particular mesencephalic nuclei showed uptake by their nerve cell soma. A specific uptake mechanism for 6-OHDA which is most likely identical with the monoamine pump may explain the well-known selectivity of the pharmacological action of 6-OHDA. Mapping of silver grain clusters and an analysis of the frequency by which they occur in different areas of the brain were performed.
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  • 42
    ISSN: 1432-1106
    Keywords: Cerebellar-development ; Autoradiography ; Cell-renewal ; Migration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The development of rat cerebellum was studied by the complete 3H-thymidine labelling method which provides a 100% labelling of cell nuclei at the time of birth. The decrease in labelling index and intensity after birth was studied for a total of 42 days in order to compare proliferative activity of the different cell populations. The results indicate that Purkinje cells and cells of the nucleus lateralis cease to divide after birth. Golgi cells showed a very slow proliferative activity up to day 20. A rapid cell turnover rate was found for basket cells and cells of the molecular layer up to day 8 and a slow proliferation at later times. A high proliferative activity of the external granular layer cells after day 3 to day 8 and a similar decline of labelling over internal granular cells was found. The latter finding was interpreted as being due to cell renewal of internal granular cells as well as cell migration from external granular cells into the internal granular layer. The transit time for the migratory process was calculated to be approximately 24 hours.
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  • 43
    ISSN: 1433-8580
    Keywords: Amiloride ; Autoradiography ; Kidney ; Potassium-saving Diuretics ; Amilorid ; Autoradiographie ; Niere ; Kaliumsparende Diuretica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Nierenaufnahme und intrarenale Verteilung von14C-Amilorid wurde nach intramuskulärer Injektion an Mäusen untersucht. 30 min nach der Injektion von 0,5–5 mg Amilorid/kg wurden Aktivitäten gemessen, die einer renalen Konzentration von 30–650 ng Amilorid/g Niere entsprechen. Der Quotient Nierenaktivität/Plasmaaktivität lag dabei zwischen 13:1 und 20:1. Anzeichen für eine Sättigung der renalen Amiloridanreicherung waren bis zu einer Dosis von 5 mg Amilorid/kg nicht zu beobachten. Mit Hilfe der Gefrierschnittautoradiographie wurde festgestellt, daß14C-Amilorid sich nach intramuskulärer Injektion vor allem im terminalen Hauptstück des Außenstreifens und im Sammelrohrlumen anreichert. Da die gleiche intrarenale Verteilung nicht nur bei anderen, im proximalen Tubulus sezernierten organischen Basen wie z. B. Histamin, sondern auch bei den sezernierten organischen Säuren wie PAH, Phenolrot, Diodrast und Furosemid vorkommt, wird für solche Bilder die Bezeichnung „proximal-sekretorisches Verteilungsmuster“ vorgeschlagen. An Hand seiner intrarenalen Verteilung werden mögliche Zusammenhänge zwischen dem Wirkungsort, dem vermuteten Wirkungsmechanismus und der Konzentration von Amilorid entlang des Nephrons diskutiert.
    Notes: Summary The renal uptake and intrarenal distribution of14C-Amiloride was studied after intramuscular injection in mice. 30 min after injection of 0.5–5.0 mg Amiloride/kg body weight, renal activities were found corresponding to 30–650 ng Amiloride/g kidney. The ratio of renal/plasma activity ranged between 13:1 and 20:1. Neither renal concentration nor this ratio reached saturation levels with doses up to 5.0 mg Amiloride/kg body weight. Cryostat section autoradiography showed high14C-Amiloride-concentrations mainly in the terminal portion of the proximal tubule (in the outer stripe of the outer medulla) and in the lumen of the collecting ducts. As identical distribution patterns have been found for other organic bases secreted in the proximal tubule (e.g. histamine) and organic acids (e.g. PAH, phenol red, Diodrast and Furosemide) the term “proximal secretory distribution pattern” for this type of radiographic image is proposed. Correlations between the mechanism and locus of action and the concentration of Amiloride in the divers segments of the nephron are discussed on the basis of the intrarenal distribution pattern.
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  • 44
    ISSN: 1432-0533
    Keywords: Cerebral Ischemia ; Protein Biosynthesis ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The incorporation ofl-[3-3H]tyrosine into cat brain proteins was investigated after 1 h of complete ischemia and 7 h of recirculation. Autoradiographs from the cerebral hemispheres, the brain stem and cerebellum revealed that the vast majority of neuronal and glial cells had resumed protein synthesis. Focal reduction of amino acid incorporation was restricted to a few cortical areas within the cerebral hemispheres. A significant number of neurons with no detectable [3H]tyrosine incorporation was only found in the dentate gyrus. The postischemic recovery of protein synthesis supports electrophysiological findings which indicate that nerve cells may survive extended periods of ischemia if the cerebral circulation can be adequately restored.
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  • 45
    ISSN: 1433-8580
    Keywords: Organ preservation ; Kidney ; Organ damage ; Hypothermia ; Perfusion ; Nuclear medicine ; Organkonservierung ; Niere ; Organschädigung ; Hypothermie ; Perfusion ; Nuclearmedizin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Funktionstüchtige und experimentell geschädigte Hundenieren wurden zur Konservierung im Belzer-Gerät hypotherm perfundiert. Die Beurteilung des Organzustandes erfolgte mit herkömmlichen Methoden (Druck/Flow-Relation, Organgewicht, Replantationsergebnis). Gleichzeitig wurden nuclearmedizinische Verfahren erprobt, mit dem Ziel, zu jeder Zeit der Konservierungsphase definitiven Aufschluß über die nach Replantation zu erwartende Funktionstüchtigkeit des Organs zu erhalten. Mit Hilfe von J131-o-Hippursäure konnte gezeigt werden, daß die Tubulusfunktion bei 5°C ruht und unter Hypothermiebedingungen nicht als Gradmesser für den Organzustand in Betracht kommt. Demgegenüber erwies sich ein sequenzszintigraphisches Verfahren als brauchbar, bei dem der In113m-EDTA-Durchsatz durch die Niere mit Hilfe eines Szintillationskamera-Computersystems bestimmt wurde. Aus Zeit-Aktivitäts-Verläufen ermittelte Parameter gaben im gesamten Konservierungsverlauf zuverlässig Aufschluß darüber, ob ein Organ intakt bzw. mehr oder weniger geschädigt war.
    Notes: Summary Uninjured as well as experimentally damaged kidneys of dogs were preserved by hypothermic perfusion according to the method of Belzer. The functional conditions of the organs were estimated by conventional methods. At the same time nuclear medical procedures have been tried in order to get more reliable information about the probable degree of organ damage at any time of the preservation phase. By means of J131-Hippurate it could be established that renal tubuli are not working at a temperature of 5°C. Therefore, Hippurate clearance can not be used as a criterion of the functional state under hypothermic conditions. Contrary to this finding the manner of transit of In113m-EDTA through the kidney yielded useful parameters for valuation of the organ. For the present investigations a Scintillation Camera-Computer System has been used which can, for routine purposes, be substituted by a simple scintillometer-recorder system.
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  • 46
    ISSN: 1432-0827
    Keywords: Calcification ; Histochemistry ; Autoradiography ; Fetal ; Mandible
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des rats femelles reçoivent du45Ca ou du32P au 13ème et 18ème jour de la grossesse. Les coupes sériées des têtes de foetus sont étudiées par autoradiographie et par diverses méthodes histologiques pour déterminer la calcification. La détection la plus précoce de45Ca s'observe simultanément comme une réaction positive pour le calcium avec une des méthodes histologiques utilisées.32P est en évidence par les méthodes autoradiographiques un peu plus tard que le45Ca et sa présence coincide avec la réaction positive la plus précoce observée avec les autres méthodes histologiques utilisées. Les os de ces têtes foetales commencent à se calcifier selon un mode particulier commençant par la mandibule, puis l'os frontal et le maxillaire supérieur, suivis par les os nasaux, pariétaux et interpariétaux.
    Abstract: Zusammenfassung Weibliche Ratten erhielten45Ca und32P zwischen dem 13.–18. Tag der Schwangerschaft. Zur Ermittlung der Verkalkung wurden Serienschnitte der Köpfe ihrer Feten mittels Autoradiographie sowie durch verschiedene histologische Methoden untersucht. Das erste Auftreten von45Ca war ebenfalls von einer positiven Calciumreaktion mittels einer der verwendeten histologischen Methoden begleitet.32P wurde in der Autoradiographie erst etwas später als45Ca festgestellt und dessen Nachweis deckte sich mit den ersten positiven Reaktonen aller anderen verwendeten histologischen Methoden. Die Knochen in diesen Fetusköpfen begannen in einer bestimmten Sequenz zu verkalken: zuerst der Unterkiefer, dann das Stirnbein und der Oberkiefer, dann das Nasenbein, die Parietal- und Interparietalknochen.
    Notes: Abstract Female rats were given45Ca or32P from 13 to 18 days of pegnancy. Serial sections from the heads of their fetuses were studied by autoradiography, as well as by several histological methods for assessing calcification. The earliest detection of45calcium occured at the same time as a positive reaction for calcium with one of the histological methods used.32P was not detectable by autoradiographic methods until somewhat later than45Ca, and its presence coincided with the earliest positive reaction with all of the other histological methods employed. The bones in these fetal heads began to calcify in a partcular sequence, the mandible first, then the frontal bone and maxilla, followed by the nasal, parietal and interparietal bones.
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  • 47
    ISSN: 1432-1440
    Keywords: Autoradiography ; cytophotometry ; DNA synthesis stages ; G0-cells ; erythropoiesis ; granulocytopoiesis ; monocytopoiesis ; megakaryocytopoiesis ; leukaemic blast cells ; Autoradiographie ; Cytophotometrie ; DNS-Synthesestadien ; G0-Zellkompartment ; Erythropoese ; Granulocytopoese ; Monocytopoese ; Megakaryocytopoese ; Leukämiezellen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über die Ergebnisse der kombinierten Anwendung von cytophotometrischer DNS-Bestimmung und autoradiographischer Markierung mit3H-TdR in vitro berichtet, die an normalen und gestörten hämopoetischen Zellsystemen gewonnen wurden. Diese Methode erwies sich für das Studium der Zellproliferation des menschlichen Knochenmarks insbesondere deshalb als wertvoll, als in-vivo-Markierungen mit radioaktiv markierten Zellbausteinen wegen der hohen Strahlentoxizität beim Menschen nur unter bestimmten Bedingungen durchführbar sind. Bei der normalen Erythropoese, Granulopoese und Monocytopoese des Knochenmarks wurden die verschiedenen Phasen des Zellcyclus (G1, S und G2) bestimmt. Die gewonnenen Daten geben Aufschlüsse über den Proliferationsablauf dieser Zellsysteme und führen auf diese Weise zu einer Verbesserung unseres Verständnisses der normalen Zellmorphologie. Bei den Anämieformen mit ineffektiver Erythropoese können drei Typen von Störungen der Zellproliferation unterschieden werden: 1. DNS-Synthese-arrest mit Anhäufung von unmarkierten Zellen zwischen 2c und 4c (megaloblastäre Anämie, kongenitale dyserythropoetische Anämie Type I), 2. Akkumulation von unmarkierten Zellen in G1 bzw. G0 (Thalassämien, kongenitale dyserythropoetische Anämie Typ II, Erythropoese bei akuter Leukämie und Präleukämie), 3. Vermehrte Zahl von unmarkierten Zellen in allen Stadien des Zellcyclus (sideroachrestische Anämie). Bei der perniciösen Anämie wurde weiterhin eine charakteristische DNS-Synthesestörung auch bei den granulopoetischen Zellen, insbesondere bei den sog. Riesenstabkernigen, und bei den Megakaryocyten gefunden. Bei der normalen menschlichen Megakaryocytopoese wurde innerhalb der Ploidiestufen 4c-32c ein Wechsel von Ruhephasen und DNS-Synthesephasen nachgewiesen (rhythmische Polyploidisierung). Es wurde gezeigt, daß die Ruhephasen in den höheren Ploidiestufen länger dauern als in den niedrigen, und daß der Hauptweg der Megakaryocytenpolyploidisierung über die Stufe 16c verläuft. Bei idiopathischer Thrombocytopenie wurde keine Störung der Megakaryocytenpolyploidisierung gefunden. Bei akuten Leukämien fand sich in den häufig zu beobachtenden Mikromegakaryocyten eine starke Einschränkung der Fähigkeit zur rhythmischen Polyploidisierung. Untersuchungen an den Blasten bei akuter Leukämie haben gezeigt, daß der größte Teil der Zellen einer diploiden Ruhezellpopulation angehört. Es ergeben sich Hinweise dafür, daß diese Zellen nicht am Zellcyclus teilnehmen und einer G0-Zellpopulation angehören.
    Notes: Summary In the present review, results are reported on the combined application of cytophotometric determination of the DNA content and3H-TdR labelling in vitro in normal and disturbed haemopoietic cell lines. This technique has been well proven particularly in kinetic studies in man in view of avoiding the problems of the high radioactive toxicity following the in vivo labelling with DNA precursors. The different stages of the cell cycle (G1, S and G2) were assessed in normal human erythropoiesis, granulocytopoiesis and monocytopoiesis. The results provided information on the proliferation pattern of these cell lines, thus leading to a much better understanding of the normal cell morphology. Three different proliferation defects are suggested in in-effective erythropoiesis: 1. DNA synthesis arrests between 2c and 4c at the tetraploid level (megaloblastic anaemia, congenital dyserythropoietic anaemia type I), 2. accumulation of unlabelled diploid cells (thalassaemia, congenital dyserythropoietic anaemia type II, erythropoiesis in acute leukaemia and preleukaemia), 3. accumulation of unlabelled cells in G1, S and G2 (sideroblastic anaemia). Furthermore, in megaloblastic anaemia characteristic defects of the DNA synthesis in granulopoiesis and megakaryocytopoiesis were observed. Normal human megakaryocytes showed ploidy stages from 4c to 32c. Evidence was provided in the study for an alternation of DNA synthesis and rest periods, and a rhythmical polyploidization. The progressive increase in the proportion of cells in successive G-phases suggests that high ploidy cells have longer rest periods than low ploidy cells. No disturbances of megakaryocytic polyploidization were observed in idiopathic thrombocytopenia. In acute leukaemia and in preleukaemia, a considerable decrease of the polyploidization capacity was found in the so called mikromegakaryocytes. Most of the blast cells in acute leukaemia in which labelling with3H-TdR was absent were diploid. The results of the combined cytophotometric and autoradiographic investigations and the labelled mitosis curve allowed for calculation of the G0-compartment, indicating that most of the blast cells were out of cycle cells.
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  • 48
    ISSN: 1432-2013
    Keywords: l-Histidine Transport ; Proximal Tubule ; Transport Kinetics ; Fanconi Syndrome ; Kidney ; Microperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The kinetics ofl-histidine reabsorption by the proximal convolution of the rat nephron have been studied by stationary microperfusion with simultaneous perfusion of peritubular capillaries. Steady-state concentrations (C ∞) and transepithelial concentration differences (Δc ∞) were determined over a wide range of peritubular bistidine concentrations. It was found that Δc ∞ increased hyperbolically with increase in luminal and peritubular histidine concentrations suggesting saturation transport kinetics. Furthermore Δc ∞ declined linearly along the convolution suggesting that nett active transport was not constant throughout the tubule. Using an expression to describe the rate of attainment of steady-state concentration in terms of lummal and peritubular histidine concentrations, histidine permeability coefficient (P), the maximum rate of active histidine transport (J max) and the half saturation constant of the transport reaction (K m ), we were able to determine the cause of the tubule inhomogeneity. We find thatP (14.1×10−5 cm/s) andJ max (45×10−10 mol/cm2· s) are constant along the convolution but thatK m increases markedly from about 5.4 mmol/kg 26% of the way along the convolution to 40 mmol/kg at 86%. These findings suggest that the histidine reabsorptive mechanism would be relatively inefficient with histidinuria occurring at all plasma concentrations but it would have enormous reserve capacity so that saturation would not readily occur. This prediction accords with available data on histidine clearance in the rat.
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  • 49
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    Springer
    Pflügers Archiv 343 (1973), S. 267-272 
    ISSN: 1432-2013
    Keywords: Kidney ; Lanthanum ; Tight Junctions ; Epithelia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The penetration of either “ionic” or “colloidal” lanthanum into the tight junctions of different tubular segments of the rat kidney was studied with the electron microscope. After perfusing the tracer through the aorta it was found that “ionic” and “colloidal” lanthanum penetrated the tight junctions of both the proximal and distal convoluted tubules, while the junctions of the collecting tubules were free of tracer. An attempt to correlate junctional tightness and electrical resistance in these epithelia is presented.
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  • 50
    ISSN: 1432-2013
    Keywords: Kidney ; Microcirculation ; Renal Blood Flow ; Acute Renal Failure ; Intravital High-Speed Microcinematography ; Peritubular Capillaries ; Welling Points
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The incident-light, high-frequency microcinematography of the kidney surface of rats is described as a new method for investigating renal microcirculation. The welling point area served as the anatomical reference point for microcirculatory measurements. In the first section of vessel distal to the welling point the average flow velocity was 2.32±0.24 mm/sec; the diameter was 15.91±0.92 microns. Flow rate in the efferent arteriole, calculated from the flow rate in the first vessel section distal to the welling point and the degree of ramification, was 103 nl/min. The results closely agree with total renal blood flow that was determined simultaneously. As an example for measurements taken under different conditions, a model for experimental acute renal failure was chosen. In kidneys subjected to a 60 min period of ischemia three days prior to use, the peritubular blood flow at the kidney surface was decreased only by 1/4; the difference in the means was insignificant. Therefore, a lasting cortical ischemia cannot be the only cause for the persistent oliguria in experimental acute renal failure.
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  • 51
    ISSN: 1432-2013
    Keywords: Saline Infusion ; Ultrafiltrable Calcium ; Parathyroid Gland Activity ; Ultrastructure of the Rat Parathyroids ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Experiments have been performed in adult female rats to examine the effects of saline infusion on calcium concentration in plasma ultrafiltrate and on the ultrastructure of the parathyroids as studied with the electron microscope. Intravenous infusions of isotonic saline of at least 10 ml within 30 min decreased calcium concentration in plasma ultrafiltrate from 3.04±0.15 mEq/l to 2.79±0.11 eEq/l (P〈0.001). Saline infusions of 2 h duration at a rate of 0.5 ml/min decreased significantly the number of secretory granules in the parathyroid cells and induced considerable growth of the Golgi apparatus. It is concluded, that saline infusions in the rat decrease the ionized fraction of plasma calcium concentration thereby increasing parathormone secretion rate.
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  • 52
    ISSN: 1432-2013
    Keywords: Antihypertensive Agents ; Desoxycorticosterone ; Kidney ; Nephrectomy ; Renin ; Sodium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In rats made hypertensive by partial constriction of one renal artery and contralateral nephrectomy, large doses of furosemide had no hypotensive effect. However, when furosemide natriuresis was followed by removal of the clamped kidney, arterial blood pressure was greatly reduced. The fall of blood pressure induced in this manner was significantly correlated with the amount of sodium and water lost. The absence of a hypotensive effect of furosemide in rats with one-kidney Goldblatt hypertension appeared to be due to enhanced renin secretion. Furosemide not followed by nephrectomy caused a fall of blood pressure in rats with one-kidney Goldblatt hypertension after renin-depletion by desoxycorticosterone and salt treatment. Sodium wastage induced by peritoneal dialysis after removing the clamped kidney also lowered the blood pressure of hypertensive rats.
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  • 53
    ISSN: 1432-2013
    Keywords: Urea ; Sodium ; Kidney ; Transport ; (Na+K)-ATPase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Microsomal ATPase activity was studied in three regions of the rat kidney: cortex, medulla and papilla. (Na+K)-ATPase activity was highest in the medulla but a substantial activity, comparable to that in the cortex, was also present in the papilla. In the presence of high sodium (200–320 mM) or urea (100–900 mM) progressive inhibition of Mg-ATPase activity was observed in all three regions of the kidney. Urea (900 mM) or Na (320 mM) caused activation of (Na+K)-dependent ATPase in the medulla and inhibition of this enzymatic activity in the papilla of the kidney. Total microsomal ATPase activity in the medulla was unchanged in the presence of urea or sodium but was reduced in the papilla. Urea inhibited non-selectively Mg-p-nitrophenylphosphatase and K-activated p-nitrophenylphosphatase in all three parts of the kidney. These findings may point to a molecular basis for the function of urea and of sodium in the concentrating mechanism of the kidney.
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  • 54
    ISSN: 1432-0878
    Keywords: Cardiac muscle ; Frog ; Regeneration ; Electron microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary From the 5th day up to the end of 3rd week following local crushing of the frog ventricle myocardium, ca. 13% of myocyte nuclei, in the vicinity of the damaged zone, were labelled after a single 3H-thymidine (3HTdr) injection, and 30–50% of these were labelled after repeated 3HTdr administration. The number of myocyte mitoses was maximal (ca. 1.3%) at the beginning of the 3rd week. The reactive proliferation of myocytes was accompanied by their “partial dedifferentiation”. This involved the nuclear euchromatic rearrangement, increase in size of nuclei and nucleoli, accumulation of the sarcoplasm rich in free ribosomes and rough endoplasmic reticulum, hyperplasia of the Golgi apparatus, and the appearance of 80–100 Å in diameter cytofilaments. Electron microscope autoradiography has shown that all these changes may be more or less pronounced in myocytes incorporating 3HTdr. The myofibril ultrastructure was found to be unchanged during S phase. However, in the mitotically dividing myocytes, the majority of Z-disks were disintegrated resulting in progressive release of myofilament bundles. Both 3HTdr labelled and mitotic myocytes were anchored to the adjacent ones by desmosomes and intercalated disks. No free myoblasts were observed.
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  • 55
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Annelida ; Sexuality and Development ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Während der sexuellen Entwicklung vonPlatynereis dumerilii steigt die Zahl der Neurone, die Merkmale einer sekretorischen Aktivität aufweisen, parallel zum Wachstum und zur Reifung der Keimzelle an. Die cytologische Differenzierung eines Neurons zur neurosekretorischen Zelle ist mit einer Steigerung der Synthese Cystin-haltigen Materials gegenüber konventionellen Neuronen gekoppelt. Neurosekretorische Zellen treten erstmals in Erscheinung, kurz bevor die Oocyten in die zweite Oogeniephase eintreten, während der die Vitellogenese abläuft. Aufgetragen gegen den Oocytendurchmesser ergibt die Zahl der Neurone, die sekretorisch aktiv werden und3H-Cystin inkorporieren, eine ansteigende Kurve. Die Kurve biegt auf ein Plateau, wenn die Oocyten eine kritische Größe erreichen. Diese Größe markiert jenes Entwicklungsstadium, von dem ab eine Enthirnung eine normale Reifung nicht mehr verhindert. Die Zahl synthetisch tätiger Neurone steight erneut an, wenn die Oocyten die kortikale Struktur des reifen Eies entwickeln. Das Maximum wird kurz vor der Metamorphose erreicht. Während der epitoken Umwandlung sinkt die synthetische Aktivität rasch ab, um im schwärmbereiten Tier gänzlich zum Stillstand zu kommen. In Tieren, die nach der kritischen Phase zur caudalen Regeneration veranlaßt werden, fällt die Zahl markierter neurosekretorischer Zellen auf ein Niveau ab, das für junge, „vorkritische“ Individuen charakteristisch ist. Entsprechend wird in jungen, vorkritischen Tieren, die erst wenige endokrine Neurone besitzen, die Differenzierung weiterer neurosekretorischer Zellen durch eine Regeneration nicht stimuliert. Der zeitliche Verlauf der synthetischen Aktivität im Zuge der Entwicklung und die durch eine Regeneration erzwungenen Veränderungen sind somit reziprok zur Aktivität des Gehirns in Bezug auf die Ausschüttung des Juvenilhormons. Die Hypothese wird zur Diskussion gestellt, die sinkende Produktion des Juvenilhormons werde von der steigenden Produktion eines antagonistischen neuroendokrinen Prinzips begleitet oder verursacht.
    Notes: Summary During sexual development ofPlatynereis dumerilii, the number of neurones exhibiting secretory activity rises in parallel with the growth and maturation of the germ cells. The cytological differentiation of neuroglandular properties is accompanied with an increased uptake of tritiated cystine. The first neurones developing the characteristics of secretory cells and incorporating cystine appear just before the oocytes enter the second growth phase which corresponds with vitellogenesis. When plotted against the oocyte diameter the number of labelled neurosecretory cells yields an ascending line, which becomes a plateau once the oocytes approach a critical size. This critical size defines the developmental stage beyond which decerebration does not prevent normal maturation. The neuronal synthetic activity rises again when the oocytes differentiate the cortical structure of ripe eggs. The curve displays its maximum slope at the onset of metamorphosis. During the epitokous transformation the synthetic activity decreases rapidly and is almost totally depressed when swarming is imminent. In animals induced to regenerate their posterior segments after they have passed the critical stage, the number of labelled neurosecretory cells becomes reduced to the precritical level. According to this, regeneration in young precritical animals containing only few endocrine neurones does not stimulate the development of further secretory neurones. Thus, the time course during maturation and the changes caused by regeneration are reciprocal to the activity of the brain with respect to the release of juvenile hormone. The question is thus raised as to whether the declining titer of juvenile hormone may be accompanied or caused by an increased production of an antagonistic principle related to maturation.
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  • 56
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Reissner's fibre ; Rana esculenta ; Light/Darkness ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The influence of long daily photoperiods and of continuous darkness on the secretory activity of the subcommissural organ (SCO) and on the growth rate of Reissner's fibre (RF) in Rana esculenta was studied in winter. The amount of aldehyde-fuchsin (AF) positive material in the apical cell parts of the SCO is smaller in light-adapted than in darkness-adapted animals. Differences in incorporation rate of 35S-cysteine between the SCO of light-adapted and of darkness-adapted animals, however, are small. The conclusion must be that light/darkness conditions only slightly influence the secretory activity of the SCO cells of Rana esculenta. In agreement with this conclusion is the observation that RF grew only slightly faster in the light-adapted than in the darkness-adapted animals. Under the conditions used RF was completely renewed in about 3 to 4 days. Influences of temperature on the activity of the SCO have been observed.
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  • 57
    ISSN: 1432-0878
    Keywords: Kidney ; Contractile structures ; Embryonic metanephros ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cytoplasmic filaments have been observed in the cells of normal and pathological kidneys. These filaments are usually grouped into bundles anchored to electron dense bodies underlying the cell membrane. In the embryonic human metanephros the filaments are found within the cells of different portions of the nephron at various stages of development. They appear first in the podocytes, almost simultaneously in the Bowman's capsule and tubular cells, then in the “mesangial cells”, and finally in the cells of the media of the afferent glomerular and interlobular arterioles. The presence of filaments and their attachment bodies in the mammalian nephron suggests that the podocytes and the so-called mesangial cells have a contractile activity, thus representing an intraglomerular apparatus which regulates the intravascular pressure, blood flow and filtration rate in the glomerular capillaries, whilst the contractile activity of the Bowman's capsule and proximal, distal, and collecting tubules, could facilitate the progression of the filtrate. The increase in number of the filaments in some pathological conditions is probably related to the functional changes of the intraluminal pressure in the glomerular capillaries, in the Bowman's space, and in the tubular lumen.
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  • 58
    ISSN: 1432-0878
    Keywords: Oocyte ; Honeybee ; Vitellogenesis ; Yolk pattern ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Oogenese der Bienenkönigin (Apis mellifica) kann in 6 Stadien eingeteilt werden. Proteinsynthese und Dottereinlagerung in der Oocyte werden autoradiographisch und mittels Trypanblau-Vitalfärbung untersucht. Euplasmatische Proteinsynthesen finden in allen Eifollikeln bis zum frühen Stadium 5 statt. Vitellogenese-aktiv sind nur die Oogenese-Stadien 3 und 4. Die pinocytäre Einschleusung dotterpflichtiger Haemolymphproteine ins Ooplasma nimmt etwa 20 min in Anspruch. 10 min später sind kleinste neugebildete Dotterkugeln in der äußersten Oocytenperipherie zu erkennen. Aus ihnen werden binnen 1 $${\raise0.5ex\hbox{$\scriptstyle 1$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 2$}}$$ —2 h große Dotterschollen von ca. 20 μm φ. Die Vitellogenese-Phase eines einzelnen Follikels dauert insgesamt 3 Tage. Dotterschollen werden nur im Bereich des freien Follikelepithels gebildet. Sie wandern einzeln ins zentrale Ooplasma ein, wo unterschiedlich alte Schollen durchmischt abgelagert werden. Dotterfrei bleibt ein Euplasmahof, der den Vorderpol des Eies markiert. Im Ooplasma und in den Nährzellen erfolgt sicher keine Synthese von Dottermaterial. Ein Beitrag der Follikelepithelzellen zur Dotterbildung kann nicht vollständig ausgeschlossen werden. Das zeitliche und räumliche Muster der Dottereinlagerung wird diskutiert unter Berücksichtigung der Determination der Oocyten-Achsen und der Präformation von ooplasmatischen Kontrollzentren für die frühe Embryogenese.
    Notes: Summary Oogenesis in the honeybee queen (Apis mellifica) can be divided into 6 developmental stages. By autoradiography and vital staining with trypan blue protein synthesis and yolk incorporation into the oocyte were studied. Euplasmic protein synthesis occurs in all egg follicles up to the early stage 5. Only the stages 3 and 4 are active in vitellogenesis. The resorption of vitellogenic haemolymph proteins by pinocytosis needs about 20 min. 10 min later very small newly formed yolk globules can be recognized in the outermost periphery of the oocyte. After 1 $${\raise0.5ex\hbox{$\scriptstyle 1$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 2$}}$$ —2 hrs large yolk platelets of ca. 20 μm in diameter arise from them. The whole vitellogenesis of a single follicle lasts 3 days. Yolk globules are formed only in the area of the free follicle epithelium. They migrate separately into the central ooplasm where yolk platelets of different age are deposited in a mixed pattern. An euplasmic halo remains free of yolk thus marking the anterior pole of the egg. It is shown that no yolk material is synthesized in the ooplasm and in the trophocytes. A contribution of the follicle epithelium to yolk formation can not totally be excluded. The temporal and spatial pattern of yolk deposition is discussed. The determination of the oocyte axis and the preformed ooplasmic reaction centers for early embryogenesis are considered.
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  • 59
    ISSN: 1432-0878
    Keywords: Kidney ; Sexual accessory organs ; Reptiles ; Secretion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Kidneys of adult male and female lizards were studied by electron microscopy, in order to understand the ultrastructure of the collecting duct and a differentiated part thereof, the sexual segment, which is an important accessory sexual organ. First portion of sexual segment in males: The cells are filled with large secretory granules of a wide range of opacities. The granular endoplasmic reticulum is abundant; basal formations of superimposed flat cisternae are frequent. Distended vesicles and microvesicles prevail in the supranuclear, well developed Golgi apparatus. Evidences indicate that secretion of these cells is holocrine. Second portion of sexual segment in males: All of the secretory granules are apical in location and relatively electron-opaque; they show a denser core. This core is formed by a substance which, after lying in contact with ribosomes, enters the secretory vesicles of the highly developed Golgi apparatus. A lighter substance is then condensed around it. The secretion of the granules is merocrine. The granular endoplasmic reticulum is very abundant in these cells, but basal ergastoplasmic formations are lacking. Sexual segment in females: The cells show features similar to those of the male first portion, but they are smaller. Undifferentiated collecting duct: Most of the cells are mucigenic. They have small ovoid, apical secretory granules. The density of the granules varies from cell to cell; when they are electron-lucent, they exhibit laminar or dotted opaque figures. Moderately developed Golgi apparatus and granular endoplasmic reticulum, as well as elongated mitochondria, occur in mucigenic cells. Intercalated among the latter are non-secretory cells. They have very abundant mitochondria, numerous microvilli, many pinocytic and smooth-membrane vesicles, whereas the organelles participating in synthetic processes are poorly developed; their function is most likely related to active solute transport.
    Type of Medium: Electronic Resource