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  • 1
    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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  • 2
    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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  • 3
    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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  • 4
    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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  • 5
    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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  • 6
    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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  • 7
    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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  • 8
    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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  • 9
    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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  • 10
    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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  • 11
    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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  • 12
    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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  • 13
    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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  • 14
    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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  • 15
    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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  • 16
    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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  • 17
    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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  • 18
    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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  • 19
    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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  • 20
    Electronic Resource
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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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  • 21
    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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  • 22
    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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  • 23
    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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  • 24
    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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  • 25
    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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  • 26
    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.
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  • 27
    ISSN: 1432-0878
    Keywords: Kidney ; Bufo bufo ; Juxtaglomerular apparatus ; Macula densa ; Light Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In a light microscopic study the course of the tubule in the kidney of the toadBufo bufo was studied. The distal tubule returning to the glomerulus of its origin appears to enclose the afferent arteriole. In that area, from which a three dimensional graphic reconstruction is made, there is an intimate contact between tubular and vascular wall. The latter contains granulated media cells. In the part of the tubule adjacent to the afferent arteriole an accumulation of nuclei is present. It is suggested that this structure is similar to the macula densa of the mammalian juxtaglomerular apparatus. The functional significance of a stricture in the tubule distally from the macula densa-like structure is discussed.
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  • 28
    ISSN: 1741-0444
    Keywords: Kidney ; simulation ; analogue ; water reabsorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Sommaire Cette communication décrit une simulation de calcul analogique du contrôle de l'osmolalité du sang au moyen du transfert d'eau à partir du tubule cortical et du tube collecteur, à travers la région médullaire, jusqu'aux vaisseaux droits. Quand la simulation est sujette aux tests séparés d'ingestion d'eau et d'injection de saline, elle produit des résultats réalistes, quand on les compare aux enregistrements de tests semblables sur l'homme et sur les animaux expérimentaux. Pour parvenir à un fonctionnement général satisfaisant de la simulation, il a été nécessaire d'inclure des facteurs qui soient compatibles avec un rôle double pour l'h.a.d. Dans le modèle, l'effect de l'h.a.d. n'est pas seulement de changer la perméabilité de l'épithélium tubulaire, mais aussi d'altérer la vitesse de l'afflux du sang et la pression hydrostatique dans les vaisseaux droits.
    Abstract: Zusammenfassung Dieser Aufsatz beschreibt die Simulation durch einen Analog Computer der Kontrolle von Blutosmolalität, mit Hilfe der Wasserübertragung von dem distal tubulus und Sammelgang durch das Mark zum vasa recta. Diese Simulation, wenn sie getrennten Testen von Wassereinnahme und Salzinjektion unterzogen ist, bringt realistische Resultate wenn man sie mit den Ergebnissen ähnlicher Versuche an Menschen oder Versuchstieren vergleicht. Um eine in allen Punkten befriedigende Simulation zu bekommen, war es notwendig, Faktoren einzubeziehen, die mit einer Doppelrolle für a.d.h. übereinstimmen. In dem Modell ist der Effekt von a.d.h. nicht nur dazu da, um die Durchlässigkeit des tubular epithelium zu ändern, sondern er verändert auch die Blutströmungsge-schwindigkeit und den hydrostatischen Druck in der vasa recta.
    Notes: Abstract This paper describes an analogue-computer simulation of the control of blood osmolality by means of water transfer from the distal tubule and collecting duct through the medulla to the vasa recta. The simulation, when subject to the separate tests of water ingestion and saline injection, produces realistic results when compared with the records of similar tests on humans and on experimental animals. To achieve the satisfactory overall performance from the simulation, it was necessary to include factors which are consistent with a dual role for a.d.h. In the model, the effect of a.d.h is not only to change the permeability of the tubular epithelium, but also to alter the blood-flow rate and hydrostatic pressure in the vasa recta.
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  • 29
    ISSN: 1432-0878
    Keywords: Kidney ; Male rat ; Proximal tubule segments ; Electron microscopy, cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars descendens (pars recta) of the proximal tubule in the male rat kidney, consisting of the terminal part of the second proximal segment (P2) and of the third proximal segment (P3), was studied with the electron microscope. A technique of tissue orientation and trimming was used which permitted precise topographic definition of the tubules studied in the electron microscope. The terminal descending part of the P2 showed some minor differences from the convoluted part of this segment, and ultrastructure also changed along the course of the P3. In the beginning of the latter segment numerous, shallow interdigitations were observed between adjacent cells; along the course of the segment they decreased in number or disappeared. In the initial part of the P3 mitochondria were more abundant than in the terminal portion of the segment and at least as numerous as in the straight part of the P2. Also, the dense, acid phosphatase-positive cytoplasmic bodies decreased somewhat in size along the course of the P3. The smooth surfaced endoplasmic reticulum reached a higher development in the P3 than anywhere else in the proximal tubules.
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  • 30
    ISSN: 1432-0878
    Keywords: Juxtaglomerular cells ; Kidney ; Teleost (Gasterosteus) ; Migration ; Kidney structure ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The renal corpuscles, juxtaglomerular cells, nephronic tubules, and ureters of female sticklebacks were studied. In fresh water fishes, the diameter of the renal corpuscles is similar to that found in fishes obtained from the sea, whereas the diameter of the glomeruli and the nuclei of the podocytes are slightly larger. Furthermore, in fresh water the podocytes produce secretory globules, which show some of the histochemical characteristics of the substance constituting the glomerular basement membrane. In sea water animals, secretory phenomena are absent. Mesangial cells, which are scarce in fresh water fishes, are numerous in marine animals. Similarly, juxtaglomerular cells, hard to find in fresh water fishes, are prominent in specimens from the sea. The development of the epithelia of the nephronic tubules and of the ureters is better in fresh water. The cells and the nuclei are larger. In the first proximal tubule, which is involved in the reabsorption and the digestion—by lysosomes—of macromolecules, “micropinocytosis vermiformis” occurs. The results of stereological analysis of the fractional volume of the mitochondria and of the relative extent of the infoldings of the basal cell membranes—the location of the ion transport mechanisms—in the three different segments of the nephronic tubule and in the ureter, point to the existence of a structural gradient along the kidney tubules. In fresh water fishes the mitochondrial volume, per surface unit of basal cell membrane, is low in the first proximal segment and is increasingly higher in the other segments, while the highest value is found in the ureter. This structural gradient may be functionally linked with osmotic and ionic gradients, which exist in the renal tubules in fresh water. In the kidney tubules of marine sticklebacks, which do not show a major osmotic gradient, the structural gradient is small. The results are discussed on the basis of the known physiological differences in the function of the kidney of euryhaline teleosts in fresh water and in the sea.
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  • 31
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    Pediatric radiology 1 (1973), S. 172-177 
    ISSN: 1432-1998
    Keywords: Kidney ; amyloidosis ; nephrotic syndrome ; familial Mediterranean fever
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Radiological changes in the intravenous pyelogram of 36 children with renal amyloidosis secondary to familial Mediterranean fever have been evaluated. Renal enlargement was consistently found. In the majority of the patients there was also a narrow rigid appearance of the ureters. The combination of these two radiographic findings appear to be virtually diagnostic of renal amyloidosis.
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  • 32
    ISSN: 1432-1912
    Keywords: Kidney ; Renal Handling ; Dopamine ; Noradrenaline ; Adrenaline ; Catechol-O-Methyl-Transferase (COMT)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In 12 female dogs renal excretion and catabolism of 14C-(±)-adrenaline, 14C-(±)-noradrenaline, 14C-dopamine and 3H-(±)-normetanephrine were investigated using a modified stop-flow technique. Radioactive compounds were infused, together with inulin, into the left renal artery for 10 min. During the first 2 min of the infusion period the left ureter was occluded. Urine samples were serially collected from both kidneys up to the end of the infusion. In the urine the total radioactivity and the pattern of radioactive metabolites were measured. On average, the infused kidney excreted from the infused dose of 14C-adrenaline 9.4% as adrenaline, 27.9% as metanephrine and 5.8% as deaminated or conjugated metabolites. From infused 14C-noradrenaline 7.4% was excreted as noradrenaline, 3.5% as normetanephrine and 1% as deaminated or conjugated compounds. When 3H-normetanephrine was infused the urine contained only radioactive normetanephrine (22.2%). From the infused dose of 14C-dopamine 9.6% was excreted as dopamine, 16.2% as 3-O-methyldopamine and 3.7% as deaminated or conjugated compounds. — Urine from the other kidney contained 1/25 to 1/5 the radioactivity of that from the infused side, but the pattern of radioactive compounds was similar. From the excretion rate of simultaneously infused inulin the filtration fraction of the infused kidney was determined. That part of the infused 14C-catecholamines which was excreted unmetabolized in the urine, corresponds to the filtration fraction in this kidney. Therefore, it is suggested, that in mammals the unmetabolized catecholamines of the urine are mainly excreted by glomerular filtration and not by tubular secretion. On the other hand, the urinary O-methylated radioactive catecholamines, which were excreted by the infused kidney at a high rate, were formed in this organ from the infused catecholamines and were excreted by tubular secretion. Thus, in mammals tubular secretion is linked to an inactivation of these compounds by O-methylation.
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  • 33
    ISSN: 1432-1912
    Keywords: Protease Inhibitor ; Peptides ; Kidney ; Absorption ; Brush Border
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A brush border membrane fraction from rat renal cortex binds the polyvalent protease inhibitor (Trasylol®) from bovine organs. Saturation is complete in the presence of about 40 nanomoles/ml of protease inhibitor. The maximal binding capacity is about 18 nanomoles (or 117 μg) of protease inhibitor per mg of brush border membrane protein. The affinity constant, as calculated from the double reciprocal plot of binding, is 7 μM. Removal of the microvillar knobs by incubation with papain does not change the binding characteristics, whereas incubation of the brush border with sialidase markedly decreases the fixation of the peptide. Guanidination fails to alter the binding properties, whereas the tetramaleoyl derivative is not fixed at all. Therefore, the positive net charge of the peptide seems to play an important role. Insulin, glucagon and bradykinin interact with the brush border fraction in a manner entirely different from that of the protease inhibitor. Over a wide concentration range, about 6 to 10% of these peptides are bound independent of the concentrations added. Our present and previous results suggest that binding to the brush border membrane is the initial step in the pinocytotic reabsorption of the protease inhibitor and possibly of other peptides too. The tremendous concentration of the protease inhibitor by the kidney cortex is assumed to be due to its high affinity to the brush border membrane in vivo.
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  • 34
    ISSN: 1432-1912
    Keywords: Gluconeogenesis ; Kidney ; N-Monomethylacetamide ; Acidosis ; Glutamine Metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Kidney cortex slices from rats poisoned with the diabetogenic drug N-monomethylacetamide (NMMAA) produced substantially more glucose from exogenous α-ketoglutarate (α-KG) than did slices from controls. The stimulation of gluconeogenesis was not due to enhancement of renal phosphoenolpyruvate carboxykinase activity, which was found to be similar in experimental and control rats. Despite acceleration of α-KG conversion to glucose, gluconeogenesis from glutamine was not stimulated. The gluconeogenic flux from α-KG, thus, was not rate-limiting for glutamine conversion into glucose. However, when the pH of incubation medium was lowered from 7.5 to 7.2, the rate of gluconeogenesis from glutamine increased together with that from α-KG in slices from both normal and poisoned rats. The data demonstrate major difference in the mechanism of stimulation of renal gluconeogenesis by NMMAA poisoning and by acidosis.
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  • 35
    ISSN: 1432-5233
    Keywords: Diabetes mellitus ; Glucose tolerance ; Kidney ; Leucine ; Serum growth hormone ; Serum insulin ; Tolbutamide ; Uremia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Dans le but de réduire au minimum les effets d'éventuelles erreus méthodologiques, l'évaluation des réponses des patients urémiques à l'administration orale de glucose et à celle intraveineuse de tolbutamide a été effectuée sur la base de l'augmentation ou de la diminution de la glycémie et de l'insulinémie. En effet les patients urémiques présentent une augmentation supérieure de la glycémie après administration orale de glucose. Dans les mêmes conditions l'augmentation de l'insulinémie est au contraire égale à celle des patients sains, tout en n'ayant aucune proportion avec l'augmentation des niveaux glycémiques. Cela démontre une oscillation ou un affaiblissement de la réponse insulinémique à l'hyperglycémie. Dans l'urémie, l'administration intraveineuse de tolbutamide provoque généralement une plus forte augmentation insulinémique et une plus forte diminution glycémique. Les patients urémiques tendent à avoir des niveaux sériques de l'hormone de la croissance plus élevés, soit avant que pendant le test oral de tolérance au glucose.
    Abstract: Resumen Para reducir todo lo posible los efectos de los eventuales errores metodológicos, se han valorado en términos de incrementos y disminuciones de la glicemia y de la insulinemia, las reacciones de pacientes urémicos al suministro oral de glucosa y de tolbutamida i.v. Tras suministro oral de glucosa, en los pacientes urémicos se observan incrementos mayores de la glicemia. Los incrementos de la insulinemia, en cambio, en esas misma condiciones, coinciden con los de los controles sanos, pero no guardan proporción con el aumento de los niveles glicémicos. Dicha pericia indica una oscilación o una debilitación de la reacción insulinémica a la hiperglicemia. En la uremia, el suministro i.v. de tolbutamida, generalmente provoca incrementos insulinémicos mayores y disminuciones glicémicas más intensas. Los pacientes urémicos tienden a presentar niveles serosos de hormón del crecimiento más altos, tanto antes como durante el test oral de tolerancia a la glucosa.
    Notes: Riassunto Per ridurre al minimo gli effetti di eventuali errori metodologici, le risposte dei pazienti uremici alla somministrazione orale di glucosio e a quella i.v. di tolbutamide sono state valutate in termini di incrementi e decrementi della glicemia e dell'insulinemia. Dopo somministrazione orale di glucosio si osservano, nei pazienti uremici, maggiori incrementi della glicemia. Gli incrementi dell'insulinemia sono invece, in queste stesse condizioni, uguali a quelli dei controlli sani, ma non proporzionati all'aumento dei livelli glicemici. Tale reperto è indicativo di una oscillazione o di un indebolimento della risposta insulinemica all'iperglicemia. Nell'uremia, la somministrazione i.v. di tolbutamide provoca generalmente maggiori incrementi insulinemici e maggiori decrementi glicemici. I pazienti uremici tendono ad avere più elevati livelli sierici di ormone della crescita, sia prima che nel corso del test orale di tolleranza al glucosio.
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  • 36
    ISSN: 1432-5233
    Keywords: Chinese hamster ; Diabetes ; Glycogen infiltration ; Kidney ; Nuclear glycogenosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Cette enquête sur l'ultra-structure du rein de hamsters chinois atteints de diabète a permis de relever des lésions glomérulaires légères, consistant en un épaississement non-homogène des membranes basales des vaisseux capillaires, des altérations de cellules de la mésange, une dilatation irrégulière des anses vasculaires. Sur la partie tubulaire, une accumulation de glycogène dans le cytoplasme des cellules de la partie distale et du tube collecteur ainsi que la présence de glycogène dans le noyau des animaux atteints d'un grave diabète et de kétose.
    Abstract: Resumen La presente investigación sobre la ultraestructura del riñón del hamster chino diabético, ha dado la posibilidad de poner en evidencia sutiles lesiones glomerulares, consistentes en el engrosamiento no homogéneo de las membranas basales de los vasos capilares, en alteraciones de las células del mesangio, en la dilatación irregular de las ansas; y, a cargo de la parte tubular, en una acumulación de glicógeno en el citoplasma de las células del tramo distal y del túbulo colector y en la presencia de glicógeno en el núcleo de los animales con diabetes grave y quetosis.
    Notes: Riassunto La presente indagine sulla ultrastruttura del rene di hamsters cinesi diabetici ha fatto rilevare fini lesioni glomerulari, consistenti in ispessimento non omogeneo delle membrane basali dei vasi capillari, alterazioni delle cellule del mesangio, dilatazione irregolare delle anse vascolari. A carico della parte tubulare, accumulo di glicogeno nel citoplasma delle cellule del tratto distale e del tubulo collettore; presenza di glicogeno nel nucleo negli animali con diabete grave e chetosi.
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  • 37
    ISSN: 1432-0533
    Keywords: Leucodystrophy Metachromatic ; Electron Microscopy ; Prismatic Deposits ; Brain ; Peripheral Nerve ; Kidney ; Rectum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Clinical history, light and electron microscopy findings are reported in four cases of infantile metachromatic leucodystrophy. By electron microscopy, the authors describe the various types of lesions and the different lipid deposits noticed in the central and peripheral nervous system, in the kidney and rectum. They stress the prismatic lipid deposits observed not only in the cerebral white matter and in the kidney but in the peripheral nerves as well.
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  • 38
    ISSN: 1432-0568
    Keywords: Human embryo ; Urinary system ; Kidney ; Bladder ; Developmental stages
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A documented scheme of the early development of the human urinary system is presented. It is based on (1) reports of workers who personally studied staged embryos, and (2) personal observations and confirmations. The necessity of studying staged embryos in order to determine the precise sequence of developmental events is stressed.
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  • 39
    ISSN: 1432-0533
    Keywords: Aspartylglucosaminuria ; Lysosomes ; Liver ; Kidney ; Brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Liver, kidney and brain biopsies were taken from patients with aspartylglucos-aminuria for electron microscopic studies. Abnormally large lysosomes were observed in all tissue specimens. In the liver, they appeared even larger than the nucleus of the same cell and were limited with a single membrane. They were most prominent in the parenchymal cells, contained finely granular, electron lucent material, and were most abundant near the bile canaliculi. Smaller lysosomes, containing electron dense material, were also observed. Rough and smooth endoplasmic reticulum were highly dilated, glycogen particles were absent, and the Golgi apparatus was always very small. In the kidney, the lysosomal changes were most prominent in the glomeruli and in the proximal tubules. The number of the lysosomes was very high. They contained homogenous, electron lucent material and additional electron dense, lipid-like droplets. In the brain biopsy specimens the number of abnormally large lysosomes was highest in the neurons but they were also present in the glial cells, pericytes and in the endothelial cells of capillaries. Their contents were more electron dense than those of the liver lysosomes. The differences in the lysosomal contents cannot at present be explained. Extrusion of the lysosomes into the kidney tubules is possible.
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  • 40
    ISSN: 1432-0533
    Keywords: Aspartylglucosaminuria ; Enzymes ; Brain ; Liver ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Brain, liver, kidney and spleen biopsy and autopsy specimens were taken from patients with aspartylglucosaminuria for biochemical investigations. Total cholesterol values for brain and liver were normal as were also the values for N-acetylneuraminic acid in brain. Lipid phosphate was slightly increased both in the brain and liver. The thin-layer chromatographic patterns of brain gangliosides and phospholipids were normal. In the group of fourteen different lysosomal enzymes the activity of N-aspartyl-β-glucosaminidase was markedly decreased in the brain, liver and spleen but not in the kidney. The activities of a number of other enzymes, especially those of N-acetyl-β-d-glucosaminidase and N-acetyl-β-d-galactosaminidase were high in the same three tissues and again normal in the kidney. No consistent abnormalities were recorded in the groups of three microsomal and three other enzymes. The biochemical findings seem to be characteristic to aspartylglucosaminuria and delineate it as a special disease entity.
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  • 41
    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 Nach chronischer Infusion hypertoner Natriumchlorid- bzw. Harnstofflösungen wurden die Eiweißgradienten im Gewebe der Rattenniere im wachen Zustand und während Narkose ermittelt. Als Indicator der Eiweißkonzentrationen diente der an Albumin gebundene Farbstoff Evans blue. Die Farbstoffkonzentration der unterschiedlichen Nierengewebsregionen ließ demnach Rückschlüsse auf die Verteilung der intravasalen und mobilen Albumine im Markgewebe zu. Die Untersuchungen zeigen eine Zunahme der Albuminkonzentrationen von der Nierenrinde bis zur Papillenspitze, wobei ein Maximum des Anstiegs bei NaCl-Belastung im wachen Zustand und in Narkose erreicht wird. Die Erklärung dieser Befunde wird in dem unterschiedlichen Verhalten der Einzelfiltratbildung der corticalen und juxtamedullären Nephrone gesehen. Für Änderungen der Eiweißkonzentrationen unter Narkosebedingungen wird eine vermehrte Wasserrückresorption durch Adiuretin-Sekretionsstimulierung verantwortlich gemacht.
    Notes: Summary The protein gradients of the tissue of the rat kidney were obtained during chronic infusion of hypertonic sodium chloride and urea solutions, both with and without the administration of anesthetic. As an indication of the protein concentrations Evans blue dye was injected, which binds to albumen. From the concentration of dye in the various tissue regions of the kidney conclusions were drawn concerning the distribution of intravascular and mobile albumen in tissue. The experiments showed an increase in the albumen concentrations from the cortex to the papillary tip, the greatest increase being obtained with NaCl solutions whilst the animals were awake or under anesthetic. These findings can be attributed to a difference in behaviour between cortical and juxtamedullary nephrones in the formation of individual filtrates. Enlarged reabsorption of water by a stimulation of ADH were held responsible for changes in the protein gradients during anesthetic.
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  • 42
    ISSN: 1432-2013
    Keywords: Growth Hormone ; Kidney ; Nephrectomy ; Liver ; Clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The metabolic clearance rate of125I-labelled sheep growth hormone (GH) in intact sheep was calculated to be 61±7.8 l/24 h and in nephrectomized sheep 26±3.9 l/24 h. From these figures a production rate of GH of 122 μg/24 h was derived for intact sheep. After a single intravenous injection of labelled GH the kidneys extracted more than 90% within 4 h. The extracted GH was metabolized by the kidney, only a small amount (5%) of the radioactivity excreted in the urine could be precipitated by perchloric acid. Renal metabolism of GH was also indicated by the appearance in renal venous blood of labelled material that was not immunoprecipitable. The liver also removed labelled GH and degraded it. Four hours after the injection of labelled GH most of the radioactivity was in blood and muscle, but there were significant amounts in kidney, liver and fat. Radioactivity that could be precipitated with GH-antiserum was found only in the kidney, thyroid and blood. A high percentage of activity extracted from all these tissues could still be precipitated by perchloric acid.
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  • 43
    ISSN: 1432-2013
    Keywords: Kidney ; Goldblatt-Hypertension ; PAH-clearance ; PAH-Metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary PAH-clearance studies were carried out separately on each kidney of both normal rats and rats with experimental Goldblatt-Hypertension. The rat and especially the rat kidney metabolizes a certain proportion of PAH-molecules 1. by splitting off the glycine-group forming p-aminobenzoate (PAB); 2. both PAH and PAB undergo partial N-acetylation. N-acetylated metabolites cannot be detected by the conventional analysis of PAH. Resorption of benzoates in the kidney results in a relatively high benzoate concentration in the renal vein. The complications created by these facts are discussed in relation to RPF-estimation using PAH. A correct determination of RPF by PAH is possible only if the analysis is carried out after an acid hydrolysis to make the detection of N-acetylated metabolites possible and if renal venous blood samples can be collected to correct for the reabsorbed benzoates. The clamped kidney of rats with Goldblatt-Hypertension is able to split glycine off from PAH but its capacity to N-acetylate is reduced. As a result identical PAH-clearances are found in both kidneys of these animals although their true RPF differ significantly.
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  • 44
    ISSN: 1432-2013
    Keywords: Kidney ; Experimental Hypertension ; DOCA ; Specific Reabsorption Capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rats were made chronically hypertensive by unilateral nephrectomy, repeated injections of desoxycorticosterone-acetate and offering saline as drinking fluid (DOCA-rats). Unilaterally nephrectomized animals (Nephrex-rats) were used for control. Compensatory renal hypertrophy was greater in DOCA-rats than in Nephrex-rats. Diameter and length of the proximal convolute in the DOCA-group increased more than in Nephrex-rats. GFR per unit kidney weight in the DOCA-group remained unchanged as compared to untreated Wistar-rats but increased significantly in Nephrex-animals. the water and sodium load of each nephron had doubled in both groups. Nevertheless, there were no substantial changes in the fractional water and sodium reabsorption in the different segments of the nephron of DOCA-rats as compared to normal animals. In Nephrex-rats fractional sodium and water reabsorption were increased in the proximal tubule and diminished in the loop of Henle and in the distal tubule. In Nephrex-rats an indirect correlation was found between blood pressure and both water reabsorption and the transit time of Lissamine green in superficial loops of Henle but no such correlation could be found in the DOCA-group. Determination of the specific reabsorption capacity of the proximal tubules during free-flow or using the split-drop technique yielded identical values in all animals studied.
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  • 45
    ISSN: 1432-0878
    Keywords: Kidney ; Stickleback ; Mucous cells ; Sexual hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Au microscope électronique, l'action de la méthyltestostérone sur les cellules rénales de l'Epinoche femelle se traduit par une cytodifférenciation conduisant à la formation de cellules glandulaires muqueuses. Elle a lieu simultanément à deux niveaux distincts: Au niveau du tubule proximal, le premier signe visible de cytodifférenciation est une activation du nucléole, accompagnée par une augmentation de taille des cellules. Puis on assiste à un développement de l'ergastoplasme et de l'appareil de Golgi et à l'élaboration de deux types de sécrétions: d'abord des granules de 2000–2500 Å, ensuite des grains de mucigène typiques, qui subissent rapidement une transformation muqueuse. Une cytodifférenciation régressive intervient en même temps. Elle concerne la pinocytose apicale qui disparaît. Au niveau des tubules collecteurs, la cytodifférenciation se traduit par la formation d'un mucus hyalin d'origine golgienne. Elle s'accompagne également d'une disparition de la pinocytose. La méthyltestostérone est capable de provoquer, chez la femelle, une cytodifférenciation rénale identique à celle que l'on observe chez le mâle pendant la période de reproduction. La transformation muqueuse des cellules rénales est donc sous le contrôle de la seule testostérone, qui déclenche au niveau cellulaire un ensemble de processus conduisant à la formation de mucus. Au microscope électronique, on constate que l'élaboration de mucus prêt à l'excrétion est achevée au bout de trois jours dans les tubules proximaux alors que dans les tubules collecteurs elle ne demande que 24 heures.
    Notes: Summary At the microscopic level, the action of methyl testosterone on the cells of the kidney of the female three-spined Stickleback gives raise to a cytodifferentiation which leads to the formation of mucous glandular cells. This action is evident at two different levels: At the level of the proximal tubule, the first visible sign of cytodifferentiation is an activation of the nucleolus, accompanied by a growth of the cell size. Then a rapid development of the ergastoplasm and the Golgi apparatus takes place, which leads to the elaboration of two types of secretory particles: granules of 2000–2500 Å in diameter appear first, then typical mucigen granules become visible. These latter undergo a rapid mucous transformation. A regressive cytodifferentiation occurs at the same time. It concerns the apical pinocytosis which disappears in the cells undergoing the glandular differentiation. At the level of the collecting tubules, the cytodifferentiation is characterized by the elaboration of a clear mucus which originates in the Golgi apparatus and migrates to the apex of the cells. A disappearance of the pinocytosis is also noticeable. In the kidney of the female, methyl testosterone induces a cytodifferentiation which is identical to that occuring in the male during the breeding period. So the mucous transformation of renal cells is under the control of a single hormone: the testosterone, which is able to give raise to a succession of phenomena leading to the formation of a mucous secretion. With the electron microscope, it is possible to demonstrate that three days are necessary for the elaboration of the mucus ready to be discharged in the lumen of the renal proximal tubules. In the collecting tubules, the reaction occurs more quickly, after only two days of treatment.
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  • 46
    ISSN: 1432-0878
    Keywords: Kidney ; Rat ; Actin- and myosin-like filaments ; Tubule and interstitial cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By electron microscopy, the prominent bundles of filaments occurring in the basal part of proximal and distal tubule cells and in interstitial cells of rat kidney cortex were studied in cells fixed by vascular perfusion, in glycerol-extracted cells and in glycerol-extracted cells treated with heavy meromyosin (HMM). The studies of perfusion-fixed tissue showed that the proximal tubule cells contained in their most basal part filamentous bundles oriented transversely around the tubule. The bundles consisted of trightly packed thin filaments (50–80 Å in diameter). Similar but less prominent bundles were found in distal tubule cells and in interstitial cells. The dimension of these filaments was similar to that of actin filaments and their insertion in the basal cell membrane of the tubule epithelial cells resembled the insertion of actin filaments in the cell membrane of smooth muscle cells. The studies on glycerol-extracted cells revealed that some tubule cells contained two types of filaments (60–80 Å and 130–170 Å in diameter) located side by side in the basal filamentous bundles. The dimension of the thick filaments corresponds well to the values for myosin filaments in glycerinated smooth and skeletal muscle. The studies on HMM-reacted renal tissue revealed that the thin filaments (60–80 Å) described in tubule and interstitial cells are probably actin filaments, as they formed characteristic arrowhead complexes morphologically indistinguishable from the complexes of HMM with actin filaments in smooth and striated muscle cells. Our results provide strong evidence that a two-filament contractile system, based on interaction of actin and myosin filaments, exists in renal tubule and interstitial cells. As a hypothesis it is proposed that it is changes in tonus of the basal filamentous system in the proximal tubule cells which stabilize the intratubular pressure, possibly via angiotensin.
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  • 47
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    Cell & tissue research 134 (1972), S. 193-204 
    ISSN: 1432-0878
    Keywords: Kidney ; Anurans ; Canaliculi cells ; Dark cells ; Electron microscopy, Enzyme cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die elektronenmikroskopische und enzymcytochemische Untersuchung der Nieren von Rana cancrivora und R. esculenta, Hyla arborea und H. regilla, Bufo carens, B. mauretanicus und B. viridis ergibt, daß im Epithel ihrer Verbindungsstücke verschiedene Zelltypen vorkommen. Die Verbindungsstücke von Rana cancrivora und R. esculenta zeichnen sich — abgesehen von dem Vorhandensein heller Zellen — durch den Besitz sog. Kanälchenzellen aus, die nach Form und Struktur an die Belegzellen der Magendrüsen erinnern. Es handelt sich um sehr mitochondrienreiche, elektronendicht erscheinende Elemente, die durch teilweise verzweigte intrazelluläre Kanälchen mit der Lichtung des Verbindungsstückes kommunizieren. Aus der Oberfläche dieser Canaliculi ragen kurze Cytoplasmafortsätze in das Lumen. An der Basis der Kanälchenzellen bilden zahlreiche Cytoplasmafortsätze ein Labyrinth, das mit den seitlichen Interzellularräumen in Verbindung steht. Die Kanälchenzellen geben eine starke Reaktion auf Bernsteinsäuredehydrogenase und NADH-Diaphorase, die dem Reichtum der Zellen an Mitochondrien entspricht. Unterschiede in der Zahl der Kanälchenzellen bei dem marinen Frosch Rana cancrivora und bei R. esculenta scheinen nicht zu bestehen. Im Verbindungsstück der untersuchten Hyla- und Bufoarten fallen dunkle, d.h. elektronendichte Zellen auf, die zwar viele Mitochondrien enthalten und ein basales Labyrinth bilden, jedoch nicht kanalisiert sind. Auch diese dunklen Zellen geben eine intensive Reaktion auf Bernstein- säuredehydrogenase und NADH-Diaphorase. Die Kanälchenzellen weisen Zeichen einer sekretorischen Aktivität (Bildung von Mukosubstanzen) auf. Die Frage, ob sie außerdem resorptiv tätig sind und ob die dunklen Zellen sowohl sezernieren als auch Ionen aktiv transportieren, kann mit den angewandten Methoden nicht beantwortet werden. Unbekannt ist ferner, ob die Unterschiede im Aufbau der Verbindungsstücke bei den Rana-Arten auf der einen und den Hyla- und sowie Bufo-Arten auf der anderen Seite zu Verschiedenheiten der Harnbildung bei diesen Formen in Beziehung stehen.
    Notes: Summary The electronmicroscopical and enzymecytochemical investigation of the kidneys of Rana cancrivora, R. esculenta, Hyla arborea, H. regilla, Bufo carens, B. mauretanicus and B. viridis reveals that the epithelium of the connecting tubule (Verbindungsstück) consists of different cell typs. The connecting tubules of Rana cancrivora and R. esculenta are characterized — apart from the occurrence of light cells — by the differentiation of so-called canaliculi cells, the shape and structure of which resemble those of the parietal cells of the gastric glands. These electron dense elements are rich in mitochondria and communicate by partly ramified intracellular canaliculi with the lumen of the connecting tubule. The plasma membrane bordering the canaliculi forms short microvilli-like processes. At the basis of the canaliculated cells numerous cytoplasmic processes form a labyrinth which is in connection with the lateral intercellular space. The canaliculi cells exhibit a strong activity of succinic dehydrogenase and NADH-diaphorase, which corresponds to the abundance of mitochondria in these cells. Differences in the number of canaliculi cells in the marine frog Rana cancrivora and the freshwater species Rana esculenta apparently do not exist. The connecting tubules of the Hyla and Bufo species investigated contain strikingly dark, i.e. electron dense cells, which contain numerous mitochondria, and which possess a basal labyrinth. Canaliculi, however, are lacking. These dark cells, too, give an intensive reaction for succinic dehydrogenase and NADH-diaphorase. The canaliculi cells show features of a secretory activity (production of mucous substances). The question, whether in addition they have a resorptive function and whether the dark cells are secretory and actively ion-transporting elements, cannot be answered by means of the methods applied. Further, it remains unknown whether the differences in the structure of the connecting tubule of the Rana species on the one hand and the Hyla-and Bufo species on the other, are related to differences in the mechanisms of urine production.
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  • 48
    ISSN: 1432-1912
    Keywords: Rare Earths ; Gluconeogenesis ; Gluconeogenetic Key Enzymes ; Liver ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After intravenous application of praseodymium nitrate, female Wistar rats develop a pronounced hypoglycemia which is due to an inhibition of hepatic gluconeogenesis. The renal gluconeogenesis remains uninfluenced. Among the gluconeogenetic key enzymes, pyruvate carboxylase and phosphoenolpyruvate carboxykinase are most drastically reduced in their activity, while there is only a slight effect on glucose-6-phosphatase and fructose-1,6-diphosphatase. An allosteric effect of praseodymium or a synthesis of an inhibitor caused by rare earths can be excluded. The activity of other enzymes which catalyse steps of both glycolysis and gluconeogenesis is not influenced. This selectivity of rare earths seems to indicate that there might be different genes for glycolysis and gluconeogenesis and led us to suppose that the site of action of rare earths is to be looked for at the nucleic acid system.
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  • 49
    ISSN: 1591-9528
    Keywords: Kidney ; Glomerulus ; Isolation technique ; Ultrastructure ; Niere ; Glomerulum ; Isoliertechnik ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Mit einer im Detail angegebenen, mechanisch schonenden Sieb-Methode wurden aus Rattennieren Glomerulumfraktionen mit einem Reinheitsgrad von 95–98% gewonnen. Dabei wurden 10 verschiedene Spülmedien benützt und ihr Einfluß auf die Ultramorphologie der Glomerula elektronenmikroskopisch kontrolliert. Nach Verwendung einer Krebs-Henseleit-Bicarbonat-Lösung mit einem pH von 7,9 ist mit der irreversiblen Schädigung des überwiegenden Teiles der Podocyten zu rechnen. Elektronenmikroskopisch befriedigende Resultate ließen sich mit einer Krebs-Henseleit-Bicarbonat-Lösung pH 7,4+3% Dextran erzielen, bei der ca. 60% der in der Fraktion enthaltenen Podocyten intakt blieben. Die restlichen 40% Podocyten waren in erster Linie mechanisch zerstört. Während Endothel- und Mesangiumzellen nach den verschiedenen Spülmedien kaum morphologische Veränderungen aufweisen, können also die Podocyten je nach Spülmedium überwiegend zerstört werden oder zu etwa 60% erhalten bleiben.
    Notes: Summary Fractions with 95–98% glomeruli have been obtained from rat kidneys with a sieve method described in detail. 10 different rinsing solutions have been used during isolation and their influence on the ultrastructure of the glomeruli has been controlled electron microscopically. The podocytes exhibit a strong edema of cytoplasm and nucleus, reaching up to cytolysis, after Krebs-Henseleit-bicarbonate-, Krebs-Ringer-phosphate- and Robinson-solution. After a Krebs-Henseleit-bicarbonate solution with pH 7.9 instead of pH 7.4 most podocytes have been damaged irreversibly. A satisfying ultrastructure resulted after solutions with a higher colloid osmotic pressure or osmotic pressure. The best results have been obtained with Krebs-Henseleit-bicarbonate solution pH 7.4+3% dextran (mol wt 40000), after which about 60% of the podocytes have been calculated to be intact. 40% of the podocytes in this fraction mainly were mechanically damaged. While endothelium and mesangium show only minor structural aberrations after the different rinsings, thus most podocytes are damaged irreversibly after Krebs-Henseleit-bicarbonate pH 7.9, and on the other hand about 60% may be intact after Krebs-Henseleit-bicarbonate pH 7.4+3% dextran.
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  • 50
    ISSN: 1432-2013
    Keywords: Na-K ATPase ; Liver ; Kidney ; Diurnal Variation ; Na-K ATPase ; Leber ; Niere ; Tagesrhythmus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a systematic investigation the course of the activities of the Na-K activated ATPase and the Mg ATPase enzyme systems in rat liver and kidney were studied. In the liver the activities of both enzyme systems were on a significantly higher level (22 and 15% resp.) during the evening hours (4:00 p. m. to 2:00 a. m.). In the kidney a significantly lower level (13%) of Na-K ATPase activity was found during the night (10:00 p. m. to 8:00 a. m.), while Mg ATPase activity did not vary significantly. The periods of raised enzyme activity in liver and in kidney did not coincide. The results are discussed in relation to literature data on diurnal variations of metabolic activities in general.
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  • 51
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    Pflügers Archiv 324 (1971), S. 1-25 
    ISSN: 1432-2013
    Keywords: Adenosine Triphosphatase ; Plasma Membrane Enriched Fraction ; Microsomes ; Kidney ; ATPase ; zellmembranangereicherte Fraktion ; Mikrosomen ; Niere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A fraction enriched with plasma cell membranes (PMF) was isolated from rat kidney homogenate by differential centrifugation. Before NaJ treatment electron micrographs of the preparation showed a membraneous fraction with only a small contamination of mitochondria. After treatment with NaJ the residual PMF exhibited a low microsomal glucose 6-phosphatase activity. Marker enzymes of other subcellular fractions were not detected. The NaJ extracted PMF revealed a high specific activity of ATPase, 91% of which was stimulated by Na+ and K+. The MgNaK-ATPase was characterized by Michaelis Menten kinetics. In contrast, Hill coefficients (“n”) of NaK-ATPase for the activation by Na+, K+ and Mg-ATP were greater than one. Experiments with various nucleotide tri-, di- and monophosphates revealed a high substrate specificity of the NaK-ATPase. The pH optimum was in the range of 7.2. SH-reagents and ouabain depressed the Na+ and K+ stimulated enzyme activity. PMF isolated from rat kidneys exhibited an acylphosphatase and a nitrophenylphosphatase activity, both of which were stimulated by K+. Furthermore 5′-nucleotidase and leucine aminopeptidase activities were present in the fraction.—Thus, NaK-ATPase of the PMF revealed the typical properties of the NaK-ATPase demonstrated in the microsomal preparations, which has been referred to by Skou (1965) as the enzymatic basis of active cation transport.
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  • 52
    ISSN: 1432-2013
    Keywords: Kidney ; Na+−K+-ATPase ; Sodium Transport ; Volume Expansion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of renal Na+−K+-ATPase in the acute changes in sodium reabsorption caused by isotonic volume expansion was evaluatedin vivo andin vitro in the rat and the dog. Duringin vivo volume expansion with isotonic saline in the rat, renal medullary Na+−K+-ATPase specific activity increased, while the simultaneously determined cortical Na+−K+-ATPase specific activity and kinetics remained unchanged. Furthermore, experimentsin vitro failed to demonstrate a circulating inhibitor of renal Na+−K+-ATPase both in plasma dialysates from volume-expanded rats and in plasma dialysates concentrated 20-fold by ultrafiltration from volume-expanded dogs. These results suggest that the decreased proximal tubular reabsorption of sodium during volume expansion is not mediated by inhibition of renal cortical Na+−K+-ATPase. The acute increment in medullary Na+−K+-ATPase observed could represent an adaptive response to increased sodium reabsorption by the loops of Henle, and raises the possibility that this enzyme may participate in relatively rapid adjustments in the transport of sodium by the renal tubule.
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  • 53
    ISSN: 1432-2013
    Keywords: Kidney ; Renal Artery ; Blood Flow Velocity ; Isoproterenol ; β-adrenergic Receptors ; Niere ; Nierenarterie ; Nierendurchblutung ; Isoproterenol ; β-Receptoren
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An wachen Hunden wurden mit einem Miniaturdruckaufnehmer der Blutdruck in der abdominalen Aorta und mit einem elektromagnetischen Flußmesser die Strömungsgeschwindigkeit in der linken Nierenarterie gemessen. Die Reaktion der Nierenstromstärke und des Blutdrucks auf rasche (〈1 sec) Injektion von 2,5, 5,0, 10,0 und 20,0 μg Isoproterenol in die abdominale Aorta proximal der Nierenarterie wurde untersucht. Bei allen vier Dosen wurde regelmäßig eine Steigerung der Nierendurchblutung und eine Abnahme des arteriellen Blutdrucks beobachtet. Die maximale Widerstandssenkung betrug im Mittel 25–30%. Während der ersten 6 sec nach Injektion erreichte die Nierenstromstärke bei noch unverändertem arteriellen Mitteldruck einen signifikant erhöhten Wert. Ebenso fand sich eine signifikant erhöhte Stromstärke, nachdem der Blutdruck sein Ausgangsniveau wieder erreicht hatte. Nach β-Blockade mit 0,5 mg/kg Propranolol hatte Isoproterenol in den verwendeten Dosen keinen Einfluß auf die Nierenstromstärke und den arteriellen Blutdruck. Das Ausmaß der beobachteten Vasodilatation läßt sich durch Autoregulation nicht erklären. Aus den Experimenten wird geschlossen, daß Isoproterenol (2,5 bis 20,0 μg i.a.) am wachen Hund in Ruhe β-Receptoren der Nierengefäße erregt.
    Notes: Summary In unanesthetized dogs abdominal aortic pressure was measured with an implanted miniature transducer, left renal artery flow velocity by an electromagnetic flowmeter. The effect of rapid injections (〈1 sec) of 2.5, 5.0, 10.0 and 20.0 μg isoproterenol into the abdominal aorta proximal to the renal artery on kidney blood flow and arterial blood pressure was investigated. Isoproterenol in every dose used regularly caused kidney blood flow to increase and arterial blood pressure to fall. The maximum decrease of resistance to flow in the average amounted to 25–30%. During the first 6 sec after drug injection kidney blood flow was already significantly elevated while arterial blood pressure was still unchanged.A significantly augmented kidney blood flow was also found when blood pressure had returned again to its original level. After β-blockade (0,5 mg/kg propranolol) isoproterenol (2.5–20.0 μg i.a.) had no effect on kidney blood flow and arterial blood pressure. The extent of the vasodilation cannot be attributed to autoregulation. It is concluded, that isoproterenol (2.5–20.0 μg i.a.) causes a β-adrenergic vasodilation in the kidney vasculature of the resting conscious dog.
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  • 54
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    Springer
    Cell & tissue research 120 (1971), S. 29-36 
    ISSN: 1432-0878
    Keywords: Kidney ; Macula densa ; Juxtaglomerular apparatus ; Bird ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The macula densa (MD) site of the kidney, at which the distal tubule is attached to the vascular pole of the glomerulus, was examined with the light microscope in domestic fowl and Japanese quail; and in the fowl also with the electron microscope. The characteristics of mammalian MD cells, as reported in the literature, are compared with those of the cells in the avian MD site. The avian cells possess some of the characteristics of mammalian MD cells and they are distinguishable from the cells in adjacent portions of the distal tubule. The Golgi system in the avian cells is apical to the nucleus, unlike in mammals where its location is basal. The cells in the avian MD sites can be considered as structurally transitional between the typical MD cells in mammals and the ordinary cells of the distal tubule. These findings are discussed in relation to the function of the avian kidney and to its control by the renin mechanism.
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  • 55
    ISSN: 1432-0878
    Keywords: Kidney ; Mesangium ; Hibernator ; Juxtaglomerular apparatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mesangial and juxtaglomerular cells were studied in kidneys of hibernating and non-hibernating ground squirrels, Citellus tridecemlineatus. In the hibernating animal, as compared with the non-hibernating, the mesangial cells show signs of increased activity. The cells are relatively larger, and numerous vacuoles appear in the cytoplasm. The juxtaglomerular cells also show signs of hyperactivity. Secretion droplets, mitochondria and free ribosomes increase in number and the endoplasmic reticulum becomes dilated. It is postulated that during hibernation, increased activity of mesangial cells slows glomerular filtration by absorption of filtrate into the mesangial matrix, and increased activity of juxtaglomerular cells results in increased renin secretion which in turn may stimulate hypersecretion of aldosterone to conserve sodium for water balance mechanisms necessary at the time.
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  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 114 (1971), S. 1-21 
    ISSN: 1432-0878
    Keywords: Kidney ; Elasmobranchs ; Glomerular Vessels ; Tubular Secretion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Glomerula und Hauptstücke der Elasmobranchierniere fallen nach lichtmikroskopischen Studien durch strukturelle Besonderheiten auf, die möglicherweise mit der physiologischen Uraemie dieser Tiergruppe in Zusammenhang stehen. Um weitere morphologische Grundlagen für spätere cytochemische und physiologische Untersuchungen zu gewinnen, haben die Autoren die genannten Nephronabschnitte elektronenmikroskopisch untersucht. Folgende Befunde wurden erhoben: 1. Die erstaunliche Dicke der Glomerulumgefäße der Elasmobranchier — sie beträgt durchschnittlich 7 μ — beruht auf der Ausbildung einer zellreichen Schicht (Durchmesser durchschnittlich 6 μ) zwischen Podozyten und Endothel. 2. Die Podozyten tragen Einzelcilien, die in den Kapselraum hineinragen, und werden von Strähnen zarter, etwa 80 Å dicker Filamente durchzogen. Möglicherweise handelt es sich um Myofilamente. Zwischen den Füßchen der Podozyten auf der Basalmembran kommen Schlitzmembranen vor. 3. Die Mittelschicht der Gefäßwand entspricht einer stark verdickten Basalmembran, in die außer Kollagenfibrillen Zellen eingebettet sind. Die Mehrzahl dieser intralamellären Zellen besteht aus verästelten Elementen, deren Ausläufer sich innerhalb der Membran ausbreiten. Im Gegensatz zu früheren Aussagen, die sich auf lichtmikroskopische Beobachtungen stützen, werden diese Zellen als fibrozytäre Elemente und nicht als glatte Muskelzellen gedeutet. Eine zweite intralamelläre Zellart, deren Elemente keine Ausläufer besitzen, fällt durch starke Entwicklung von Ergastoplasma auf. 4. Das relativ dicke Endothel der Glomerulumgefäße besitzt eine stark zerklüftete Oberfläche, seine Pseudofenestrierung ist weniger regelmäßig als in den Glomerula höheren Formen ausgebildet. 5. Verschiedene Zustandsbilder einer Abschnürung von vacuolär strukturierten Blasen und von Protuberanzen, die möglicherweise das Äquivalent einer apokrinen Extrusion aus den Hauptstückzellen sind, werden beschrieben. Die Frage bleibt offen, ob dieser Vorgang etwas mit der Abgabe harnpflichtiger Substanzen in das Lumen des Kanälchens zu tun hat. Es handelt sich bei diesen Strukturen nicht um Fixationsartefakte. 6. Die von Lichtmikroskopikern beschriebenen „Basalreifen“ des Nierenkanälchens entsprechen leistenartigen Erhebungen der Innenfläche der Basalmembran. Das Bild der „basalen Kittfäden“ dürfte durch die Cytoplasmapartien zwischen den Basalreifen hervorgerufen werden.
    Notes: Summary According to light microscopical studies glomerula and proximal convoluted tubules of the elasmobranch kidney are characterized by structural peculiarities, which possibly are related to the physiological uremia of this group of animals. In order to obtain morphological fundamentals for cytochemical and physiological studies, the authors have investigated the above mentioned parts of the nephron with the electron microscope. The results are as follows: 1. The remarkable thickness of the glomerular tufts in the elasmobranchs—averaging 7 μ—is due to the presence of a cell-rich layer (diameter about 6 μ) between podocytes and endothelium. 2. The podocytes bear individual cilia protruding into the capsular space. They further contain bundles of fine filaments (diameter approximately 80 Å) which possibly are myofilaments. Between the feet of the podocytes slit membranes occur on the surface of the basement lamina. 3. The medium layer of the vascular wall corresponds to a strongly thickened basement lamina, into which besides collagen fibrils and fuzzy material different cells are embedded. The majority of these intralamellar cells consists of branched elements the processes of which spread inside the membrane. In contrast to earlier statements, which were based on light microscopical observations, these cells are interpreted to represent fibrocytic elements and not smooth muscle cells. A second intralamellar cell type which does not possess any processes, is marked by well developed cisternae of rough endoplasmic reticulum. 4. The relatively thick endothelium of the glomerular vessels possesses a rugged surface, its pseudofenestration beeing less regular than in glomerular capillaries of higher vertebrates. 5. Vesiculated spherical bodies, swollen cellular apices and protuberances apparently being pinched off in the proximal convoluted tubule—possibly equivalents of an apocrine extrusion—are described. The authors are of the opinion that these structures do not represent artifacts caused by fixation. It remains on open question, whether this extrusion contributes to the composition of the tubular urine. 6. The “Basalreifen” of the kidney tubule as have been described by light microscopists, correspond to crests of the inner surface of the basement lamina, the “basale Kittfäden” to the strips of cytoplasm between these “Basalreifen”.
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  • 57
    ISSN: 1432-0878
    Keywords: Kidney ; Triturus cristatus ; Juxtaglomerular apparatus ; Cell types
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1)As in mammals, the juxtaglomerular apparatus of the Newt (Triturus cristatus) is composed by cells of the media of the afferent glomerular arteriole and by cells of the intermediary tubule. 2) The cells of the media of the glomerular arteriole are of two different types: granular and agranular cells. 3) The intermediary tubule is formed by dark and light cells. 4) Part of interrenal body is located close to glomerular arteriole and intermediary tubule.
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  • 58
    ISSN: 1432-1912
    Keywords: Carbohydrate Metabolism ; Kidney ; Enzymic Determination of Substrates ; 6-Aminonicotinamide ; Adrenalectomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After application of 6-aminonicotinamide (6-AN), a strong accumulation of 6-phosphogluconate was found in rat kidney. The accumulation of 6-phosphogluconate influences the activity of the phosphoglucose isomerase. The enzymic determination of the substrate concentrations of the carbohydrate metabolism after application of 6-AN revealed that fructose-6-phosphate and lactate as well as phosphoenolpyruvate are significantly increased in the kidney as compared to the controls. The increase in phosphoenolpyruvate might be caused by stimulated gluconeogenesis, as the application of 6-AN increases the release of corticosterone from the adrenal cortex. After adrenalectomy, the accumulation of 6-phosphogluconate is decreased, the ratio glucose-6-phosphate/fructose-6-phosphate is normalized, and also the values for lactate and phosphoenolpyruvate decrease. The effects of adrenaline seem to involve the passage of glucose through the pentose phosphate pathway. There is probably a relationship between the blockade of the oxidative pentose phosphate pathway and the stimulation of gluconeogenesis in the kidney, the mechanism of which is unknown. In contrast to the findings in the brain, no changes could be established in the concentrations of citrate and 2-oxoglutarate.
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  • 59
    ISSN: 1432-5233
    Keywords: Diabetes ; Duodenum ; Kidney ; Pancreas ; Rejection ; Transplant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Il a été mis au point une méthode de laboratoire pour l'allogreffe pancréatico-duodénale chez le chien pancréatectomisé. Les animaux chez lesquels de telles greffes ont été pratiquées ont survecu plusieurs mois, si on les a traités avec azathioprine et prednisone afin de prévenir le rejet. Contrairement à ce que l'on pense généralement, le pancréas n'est pas particulièrement sensible à l'ischémie totale, étant donné qu'il y a été possible de conserverin vitro jusqu'à 24 heures d'allogreffes pancréatico-duodénales, en employant uniquement l'hypothermie et l'hyperbarie. Ces blocs pancréatico-duodénaux conservés ont été en suite allograffés chez des chiens pancréatectomisés, en obtenant la survie des animaux durant de longues périodes. Nous venons de pratiquer une allogreffe pancréatico-duodénale chez des malades avec diabète juvénile et insuffisance rénale. Parmi ces sujets, 9 ont reçu en même temps une allogreffe rénale prélevée du cadavre. Chez tous ces patients, sauf un, le pancréas a fonctionné immédiatement. Cette exception est représentée par un sujet qui a reçu une allogreffe pancréatico-duodénale prélevée du cadavre après avoir subi une ischémie irréversible. Bien que deux patients seulement soient actuellement en vie (maximum depuis onze mois), nous n'avons jamais observé de signes de rejet du pancréas. Dans 7 cas sur 8 la morte