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  • Inorganic Chemistry  (809)
  • Rat  (36)
  • 1990-1994
  • 1970-1974  (845)
  • 1955-1959
  • 1930-1934
  • 1970  (845)
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  • 1990-1994
  • 1970-1974  (845)
  • 1955-1959
  • 1930-1934
Year
  • 1
    ISSN: 1432-1106
    Keywords: Auditory evoked potentials ; Sleep ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Click-evoked potentials were recorded from the rat's auditory cortex (AC), medial geniculate body (MGB), reticular formation (RF), and hippocampus (HIPP) during natural sleep and waking. Various amplitude measurements made on sliding averages by a computer provided essentially continuous measurement of evoked responses in long experiments. Changes in AC responses were simplest in potentials recorded from a depth of 1.0–1.5 mm, all components of the average waveform being larger during slow-wave sleep (SS) than in waking (W) and low-voltage fast sleep (LVFS). More complex changes in cortical surface responses included increases in the first positive wave, in a second positive deflection, and in a late negative wave during drowsiness (D) and SS. The second positive wave remained large during LVFS, while the late negativity changed form and peaked earlier. Early components of both surface and deep responses were not consistently different in W and LVFS. The only clear change in MGB responses was a reduction in amplitude during LVFS. Late positive waves in RF and HIPP responses were large during SS and small during W and LVFS. In general, increases in the very late components of responses at all sites distinguished periods of cortical synchrony from periods of cortical activation. The first negative deflection and a succeeding positive wave in the HIPP response were markedly increased during arousal.
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  • 2
    ISSN: 1432-1106
    Keywords: Visual pathway ; Hypothalamus ; Arcuate nucleus ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Degenerating nerve fibres and boutons were searched with the aid of the electron microscope in the arcuate nucleus of rats 2–7 days after bilateral destruction of the retina. In the arcuate nucleus of the control animals as well as in the operated animals, 4 types of boutons were distinguished on the basis of vesicular contents and glial ensheathment. In the operated animals changes interpreted as degenerating were found in small myelinated axons and boutons of type II (boutons containing both synaptic and granular vesicles). The changes were similar to those described in the literature as the “dark” type of degeneration in experimentally interrupted axons and boutons. Similar changes were not found in the unoperated animals. The conclusion is reached, that a small number of fibres of the optic tract reach the arcuate nucleus to terminate here.
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  • 3
    ISSN: 1432-1106
    Keywords: Subcellular fractionation ; Axons ; Synaptosomes ; Whole brain ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Subfractionation of a standard “synaptosome” fraction from whole brain has yielded two lighter layers rich in axonal segments devoid of synaptosomes similar to those obtained from cerebellar homogenates. The heavier layers were found to contain both synaptosomes and axonal segments plus a significant population of synaptosomes with axons attached. Quantitative studies of the percent perimeter of external membrane contributed by the various elements within the subfractions showed that the major constituents in decreasing order were axonal segments, synaptosomes, membranes of undetermined origin and free mitochondria. These findings have revealed that “synaptosome” preparations are more heterogeneous than previously reported and at the same time have indicated the possibility of future studies on axonal preparations from whole brain. Correlated biochemical data strongly suggest chemical differences in fractions rich in axonal segments in contrast to those enriched in synaptosomes.
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  • 4
    ISSN: 1432-1106
    Keywords: Visual pathway ; Hypothalamus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following unilateral retinal destruction in rats the existence of a direct retinohypothalamic pathway was investigated using the Nauta and the Fink-Heimer methods. Critical analysis of the Fink-Heimer stained sections of the experimental animals suggests that fibres leaving the optic pathway pass to various hypothalamic nuclei: 1. Fibres from the dorsorostral part of the chiasm pass through the lamina terminalis and appear to end in the preoptic and anterior hypothalamic nuclei. 2. Fibres leaving the ventrocaudal border of the chiasm and optic tract pass to the arcuate and ventromedial hypothalamic nuclei. 3. From the dorsocaudal part of the chiasm fibres pass to the suprachiasmatic and ventromedial hypothalamic nuclei. 4. From the caudal part of the inferior bundle of the accessory optic tract fibres pass to the premamillary ventral nucleus. The amount of apparently terminal degeneration in the preoptic, anterior hypothalamic, suprachiasmatic and premamillary nuclei was small. Heavier terminal degeneration appears to be present in the arcuate and ventromedial hypothalamic nuclei.
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  • 5
    ISSN: 1432-0568
    Keywords: Rat ; Early development ; Jolk-sac entoderm ; Reichert's membrane ; Trophoblast-cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Rattenkeime des Schwangerschaftstages 7–10 wurden elektronenmikroskopisch untersucht. Das viscerale einschichtige Dottersackentoderm zeichnet sich durch eine ausgeprägte endocytotische Aktivität aus. Die Zellen des parietalen Blattes dagegen liegen isoliert der Reichertschen Membran innen an und enthalten vorwiegend rauhes endoplasmatisches Reticulum. Die Reichertsche Membran besteht aus einem lockeren Maschengitter feiner Filamente. Im antimesometrialen und lateralen Bereich haften nur wenige Trophoblastenzellen dieser Membran von außen an, dazwischen befinden sich weite Lücken. Zum mütterlichen Gewebe hin wird der Keim mit Ausnahme des mesometrialen Poles von einem bis zu 50 μ breiten periembryonalen Sinus umgeben, der mütterliches Blut enthält. Nach außen wird dieser Raum durch Trophoblasten- und Deciduazellen abgedichtet. Aus diesen Befunden wird geschlossen: 1. Die Reichertsche Membran wird vom parietalen Dottersack-Entoderm gebildet. 2. Mütterliches Blutplasma kann frei das viscerale Dottersack-Entoderm erreichen, da als einzige kontinuierliche Schicht zwischen Blut und Träger nur die weitmaschige Reichertsche Membran vorhanden ist. 3. Durch das endocytotische und lysosomale System des visceralen Dottersackentoderms wird das anströmende mütterliche Plasma aufgenommen, abgebaut und für den wachsenden Keim nutzbar gemacht. 4. Immunbiologisch betrachtet können Antikörper der Mutter den Keim erreichen. 5. Embryonale Antigene dagegen erreichen durch die Errichtung einer Deciduabarriere nicht den mütterlichen Kreislauf. 6. Der periembryonale Sinus stellt einen Blindsack dar, in den zwar mütterliches Blut einströmen kann, ein Ausstrom aber nicht mehr möglich ist.
    Notes: Summary Electron microscope studies of rat embryos were performed from the 7th to 10th days of pregnancy. The single-layered visceral yolk entoderm is characterized by a marked endocytotic activity. The cells of the parietal layer lie separately adjacent to the Reichert's membrane and they contain mainly rough endoplasmic reticulum. The Reichert's membrane consists of a loose network of fine filaments. In the antimesometrial and lateral sites only few trophoblast cells are seen to be attached to the membrane. Between them we find large gaps. With the exception of the mesometrial pole, the embryo is surrounded by a periembryonal sinus, 10–50 μ wide, which contains maternal blood. This sinus space is sealed tightly (zonulae occludentes) by trophoblast and decidual cells. From these findings it was concluded: 1. Reichert's membrane is formed from the parietal jolk sac entoderm. 2. The porous Reichert's membrane permits the maternal plasma to reach freely the visceral jolk sac entoderm. This membrane is the only continuous layer between blood and egg cylinder. 3. By the endocytotic and lysosomal system, the visceral jolk sac entoderm absorbs the plasma coming from the mother. This plasma is degraded and used for the growing embryo. 4. From the immunobiological point of view the antibodies from the mother can reach the embryo freely, 5. The embryonal antigens cannot reach the maternal circulation because of the presence of a decidual barrier, 6. The perimebryonal sinuses are blind sacs into which the maternal blood can flood but it cannot return.
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  • 6
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    Electronic Resource
    Springer
    Anatomy and embryology 131 (1970), S. 236-242 
    ISSN: 1432-0568
    Keywords: Cartilage ; Ear, external ; Differentiation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The differentiation of cartilage in the external ear of the rat proceeds in four steps. Each of them is characterized by a specific biosynthetic activity of the chondroblast resulting in the appearance of a new structural component of the tissue: collagen fibrils, elastin fibers, cartilage ground substance and intracellular fat droplets. As a structurally and developmentally well-defined “subspecies” of cartilage, this tissue might serve as a suitable object for the experimental approach to some essential problems in histodifferentiation.
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  • 7
    ISSN: 1432-0533
    Keywords: Ependyma ; Thiobarbiturate ; Rat ; Hypothalamus ; III. Ventricle ; Narcosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An 14 männlichen Ratten wurde nach langdauernder intraperitonealer Narkose mit Thiobarbiturat Veränderungen des Ependyms im III. Ventrikel festgestellt. In der Gegend über dem Nucleus ventromedialis und Nucleus dorsomedialis hypothalami lassen sich zwei Formen des Ependyms unterschieden: 1. ein einschichtiges hohes Ependym mit runden großen Zellkernen, 2. ein mehrreihiges flaches Ependym mit schmalen, ovalen Zellkernen. Das flache Ependym zeigt folgende Veränderungen: Farbdichte und die Menge des färbbaren Materials im Kern nehmen zu, die Kernmembran ist gefaltet, der Kern zeigt Zeichen der Schrumpfung und Pyknose. Die Kontrollgruppe wurde mit Curare behandelt. Eine statistische Sicherung erbrachte einen signifikanten Unterschied mit einer Irrtumswahrscheinlichkeit von 0,5‰.
    Notes: Summary Alterations in the ependyma of the third ventricle were caused by continuous intraperitoneal thiobarbiturate narcosis in14 male rats. In the region of the nucleus dorsomedialis and ventromedialis hypothalami two kinds of ependyma can be distinguished, 1. a simple cuboidal ependyma with a large rounded nucleus, and 2. a stratified squamous ependyma with a slender oval nucleus. The squamous ependyma shows the following changes. The depth of staining and the chromatin material of the nucleus increases, the membrane of the nucleus is folded, the nucleus shows the signs of shrinkage and pyknosos. The control group was treatened with Curare. The significant difference of the results encloses 0.5‰ probability of error.
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  • 8
    ISSN: 1432-0738
    Keywords: Mercury ; Enteral Absorption ; Neutron Activation Analysis ; Rat ; Quecksilber ; enterale Resorption ; Neutronenaktivierungs analyse ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Durch Neutronenaktivierungsanalyse wird nachgewiesen, daß bei der Eatte von symptomlos vertragenem metallischem Quecksilber, oral zugeführt, ein geringer Anteil resorbiert wird, welcher zu einer Erhöhung der Queeksilberwerte in Blut und Niere auf reichlich das 10fache der Norm führt.
    Notes: Summary It was demonstrated by means of neutron activation analysis that a small portion of orally administered metallic mercury is absorbed by rats. The animals tolerated this without visible symptoms, yet it resulted in a 10-fold or greater increase above normal values of mercury in blood and kidneys.
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  • 9
    ISSN: 1591-9528
    Keywords: Hepatic microcirculation ; Intravital microscopy ; Haemorrhagic hypotension ; Rat ; Mikrozirkulation der Leber ; Intravitalmikroskopie ; hämorrhagische Hypotension ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Auswirkungen eines massiven Blutverlustes auf die Blutströmung in den Sinusoiden der Leber bis zum Zusammenbruch der Mikrozirkulation sind fÜr das Ausmaß und die Reversibilität der akuten Blutungsfolgen wesentlich. Während kontrollierten Entblutens wurde bei der Ratte an einem vorgelagerten Leberlappen die Mikrozirkulation intravitalmikroskopisch im Durchlicht beobachtet. Durch die Anwendung einer Modifikation vorliegender Methoden waren gleichzeitige Druckmessungen in der Vena portae und in einer Arteria carotis möglich. Die gewonnenen Ergebnisse bestätigen die Brauchbarkeit der Versuchsanordnung. Zu einem vollkommenen Strömungsstillstand in allen sichtbaren Sinusoiden kommt es nach langsamem Entbluten von durchschnittlich 30% des Blutvolumens. Der Druck in der Arteria carotis ist dabei von 89,25 auf 21,4 mm Hg, der portale Druck von 92,3 auf 31,4 mm H2O abgefallen. Die Korrelation zwischen dem arteriellen und dem portalen Druck bleibt während dieses Abfallens erhalten.
    Notes: Summary The sequels of a massive haemorrhage on the blood flow in the sinusoids of the liver until the microcirculation breaks finally down, are essential for the degree and the reversibility of acute complications of the haemorrhage. The microcirculation of the exposed rat liver has been observed by intravital microscopy by means of transillumination during controlled desanguination. A modification of methods previously used made it possible to measure simultaneously systemic and portal blood pressure by portal and carotic arterial catheters. The results obtained proved the reliability of the method. A complete flowstop in all visible sinusoids has been observed after slow drainage of 30% of the blood volume. At this stage the blood pressure in the carotic artery has decreased from 89.25 to 21.4 mm Hg and the portal pressure from 92.3 to 31.4 mm water. The correlation between the arterial and the portal blood pressure remained unchanged during this decrease.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Clinical and experimental medicine 152 (1970), S. 352-355 
    ISSN: 1591-9528
    Keywords: Aurothiomalate ; Penicillamine ; Diethylenetriaminepentaacetate ; Rat ; Aurothiomalat ; Penicillamin ; Diäthylentriaminpentaacetat ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurde der Einfluß der D- und L-Isomeren von Penicillamin sowie von Diäthylentriaminpentaacetat auf die Organverteilung von Gold bei der Ratte untersucht. Während Diäthylentriaminpentaacetat sich als unwirksam erwies, wird Gold durch Penicillamin in nur geringem Maße mobilisiert. Der klinische Wert von Penicillamin als mögliches Antidot bei der Chrysotherapie erscheint somit fraglich.
    Notes: Summary The influence of the D- and L-isomeres of penicillamine as well as of diethylenetriaminepentaacetate on the distribution of gold in the organs of the rat was studied. Whereas diethylenetriaminepentaacetate proved to be ineffective, penicillamine brings about a marginal mobilization of gold only. The clinical value of penicillamine as possible antidote in chrysotherapy, therefore, is doubtful.
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  • 11
    ISSN: 1432-2072
    Keywords: Nicotinamide Adenine Dinucleotide ; Variable Interval Schedule ; Sidman Avoidance ; Sedative Effects ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of nicotinamide adenine dinucleotide (NAD) upon the response rates in variable interval and Sidman Avoidance schedules was studied in rats. Bar pressing on the variable interval reinforcement schedule was significantly reduced during the 15 min following the administration of 10 mg/kg i.p. and during the 60 min following the administration of 30 mg/kg NAD. Response rates on the Sidman Avoidance schedule were significantly reduced during the 60 min following the administration of 100 mg/kg NAD.
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  • 12
    ISSN: 1432-2072
    Keywords: Rat ; Swimming Endurance ; Nicotine ; Tobacco Alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The swimming endurance of rats in a water tub was measured until the animals submerged for two seconds under the water surface. The total alkaloid fraction extracted from cigarette smoke produced deterioration of performance in doses of 0.05 to 0.2 mg/kg, whereas pure nicotine (0.1 and 0.2 mg/kg), as well as nicotine pretreated analogously to the extraction process of the total alkaloids produced performance improvements.
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  • 13
    ISSN: 1432-2072
    Keywords: Rat ; Avoidance ; Extinction ; Nicotine ; Tobacco Alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of nicotine and total alkaloids extracted from smoke on the avoidance behavior of rats under extinction procedure has been measured in an experiment extended over a period of three months. There was no significant difference between the two substances, with both inhibiting the extinction of avoidance response to approximately the same degree. Significance against the control was achieved with all treatments, the effect being significantly greater with the dose of 0.2 mg/kg than with the two doses of 0.1 or 0.05 mg/kg.
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  • 14
    ISSN: 1432-2013
    Keywords: Renin ; Angiotensin ; Electrolytes ; Kidney Slices ; Rat ; Renin ; Angiotensin ; Elektrolyte ; Nierenschnitte ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Nierenschnitte von Wistarratten wurden in NaCl-Lösungen oder in Ringer-Bicarbonat(bzw. Phosphat-)-Puffern mit 0,1 g Glucose/l für 2 Std bei 37° C aerob inkubiert. 0,1 ml Medium wurde mit 1,9 ml Rinder-Reninsubstratlösung in Anwesenheit von Diisopropylfluorophosphat und EDTA bei pH 5,7 und 37° C für 2 Std inkubiert. Der Angiotensingehalt des Inkubates wurde im Blutdrucktest der Ratte bestimmt. In verschieden konzentrierten NaCl-Lösungen nimmt die Reninabgabe von 150–67 m Val/l (Na+) kontinuierlich ab. Auch in Ringer-Lösungen mit abnehmender NaCl-Konzentration und konstanter Konzentration der übrigen Elektrolyte findet sich zwischen 120 und 50 m Val/l (Na+) ein steiler Abfall der Reninabgabe. Bei Konstanterhaltung der Osmolarität durch zunehmenden Ersatz des NaCl durch Cholinchlorid oder Mannit vermindert sich die Steilheit der (Na+)-Abhängigkeit der Reninabgabe. Ersatz des NaCl im Bicarbonatpuffer durch verschiedene Konzentrationen von NaBr ergibt die gleichen Befunde wie mit NaCl. Bei vollständigem Ersatz des NaCl im Puffer durch verschiedene Konzentrationen von Chlolinchorid oder Mannit ist die Konzentrationsabhängigkeit der Reninabgabe weniger deutlich, bei Ersatz durch KCl nicht mehr signifikant. Die (Na+)-Abhängigkeit der Reninabgabe aus Nierenschnitten scheint nicht vom aeroben Stoffwechsel abhängig zu sein.
    Notes: Summary Rat kidney slices were incubated in saline solutions or in Ringer-bicarbonate (resp. phosphate-)-buffers containing 0.1 g/l glucose for 2 hrs at 37° C. Subsequently, 0.1 ml of the medium was incubated with 1.9 ml of ox renin-substrate solution, pH 5.7, for 2 hrs at 37° C in the presence of diisopropylfluorophosphate and EDTA. The angiotensin formed was measured by rat blood pressure assay. Renin release from kidney slices decreases markedly in NaCl-solutions between Na+-concentrations of 150 meq/l and 67 meq/l. Renin release decreases likewise in modified Ringer-solutions containing decreasing amounts of NaCl or NaBr (between 120 meq/l and 50 meq/l Na+), when the concentrations of other electrolytes are held constant. The (Na+)-dependence of renin release is less marked when the osmolarity of the medium is held constant by stepwise substitution of NaCl cholinchloride. Complete substitution of NaCl by different concentrations of cholin-chloride or mannitol diminishes the dependence of renin release on the osmolarity of the medium. Variation of KCl-concentration in the absence of NaCl does not influence renin release significantly. The (Na+)-dependence of renin release does not seem to depend on aerobic conditions.
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  • 15
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    Electronic Resource
    Springer
    Psychopharmacology 17 (1970), S. 234-241 
    ISSN: 1432-2072
    Keywords: Specific Inhibition of Amine Synthesis ; Brain ; DMI and RO 4-1284 Antagonism ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The influence of α-methyl tyrosine and diethyldithiocarbamate which specifically inhibit noradrenaline synthesis and the influence of p-chlorophenylalanine which inhibits 5-hydroxytryptamine synthesis in the brain on the antagonism between desmethylimipramine and RO 4-1284 was studied. It was shown that both substances which inhibit noradrenaline synthesis abolish the behavioural antagonism between DMI and RO 4-1284, and p-chlorophenylalanine is without effect on this antagonism. The evidence shows that DMI antagonises the action of a benzoquinolizine derivative by the participation of adrenergic mechanisms.
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  • 16
    ISSN: 1432-2072
    Keywords: Scopolamine ; Hippocampus ; Activity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To test the hypothesis that the hippocampus may be an important site of action for anticholinergic drugs, scopolamine was administered to rats with hippocampal lesions produced by aspiration and to appropriate control groups, and their activity measured. The experimental design was a four-way analysis of variance with three lesion groups, three drug levels, eight measurements in a two-hour session, and four weeks. At the two higher drug doses (0.20 and 1.0 mg/kg), rats with hippocampal or cortical lesions had significantly greater activity than the sham operates (p〈0.01 and p〈0.05, respectively). A group of Ss with electrolytic hippocampal lesions tested at 0.20 mg/kg scopolamine had transitory activity increases. Therefore the hippocampus is not necessary for the motor activating effects of the drug nor is its ablation unique in producing increases in drug-induced activity.
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  • 17
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    Electronic Resource
    Springer
    Psychopharmacology 16 (1970), S. 369-374 
    ISSN: 1432-2072
    Keywords: Noradrenaline ; Intraventricular Injection ; Rat ; Behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The behavioural effects of NA injected without narcosis into the lateral brain ventricle of the rats were studied with two different techniques. Rats were classified according their normal level of exploratory activity into three groups: high, medium and low. It was shown that NA in a dose of 10 μg increased locomotor activity only in animals of low activity; a dose of 50 μg increased locomotor activity in all the animals; and a dose of 200 μg induced a complete abolition of locomotor activity and a stuporose syndrome lasting 2 hours. The evidence that NA in some experimental conditions increases locomotor activity of rats supports the hypothesis that NA regulates processes in the central nervous system which stimulate behaviour.
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  • 18
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Rat ; Trypsin-dissociation ; ACTH stimulation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron micrographs of trypsin-dissociated rat adrenal showed predominantly intact rounded cells without internal damage. The population contained cells from the glomerular, intermediary and fascicular zones with cells from the zona fasciculata predominant. The presence or absence of cells from the reticular zone could not be determined. Cells from the medullary zone were absent. The addition of adrenocorticotropic hormone (ACTH) to the cellular suspension for 2 hours produced corticosterone. However, these stimulated cells did not display any significant ultrastructural change.
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  • 19
    ISSN: 1432-0878
    Keywords: Muscle Spindles ; Different types of sensory endings ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In einer Muskelspindel der Ratte, die an einer Serie alternierender Semidünn- und Ultradünnquerschnitte untersucht wurde, wurden zwei benachbart an „nuclear chain“-Fasern gelegene Nervenendformationen unterschiedlicher Bauweise festgestellt. Die beiden Endformationen sind mit ein und derselben Nervenfaser der Gruppe II verbunden und daher als Bestandteile einer sekundären sensorischen Endigung zu betrachten. Die Nervenendformation an einer der beiden „nuclear chain“-Fasern hat anulo-spirale Form. Die Nervenendformation an der anderen „nuclear chain“-Faser weist am Querschnittsbild eine Anzahl von Axonen auf, die zwischen Plasmalemm und Basalmembran der intrafusalen Muskelfaser eng aneinanderliegen. Nicht alle Axonquerschnitte stehen in direktem Kontakt mit der intrafusalen Faser. Das terminale Axon scheint sieh nach Eintritt unter die Basalmembran der intrafusalen Faser mehrfach in relativ dünne Äste unregelmäßigen Verlaufs zu teilen. Diese Form der Endigung könnte ein Korrelat der sog. „flower spray“-Endigung im Sinne Ruffinis (1898) darstellen. Die beiden morphologisch unterschiedlichen Endformationen innerhalb der sekundären Endigung gleichen einander und den Endformationen der primären Endigung bezüglich folgender Ultrastrukturmerkmale: 1. Es besteht synaptischer Kontakt zwischen Axon und intrafusaler Muskelfaser (synaptischer Spalt durchschnittlich 200 Å) ohne Zwischenlagerung von Basalmembranmaterial; 2. die terminalen Axonabschnitte liegen direkt unter der Basalmembran der intrafusalen Muskelfaser und sind nicht von Schwannschen Zellen bedeckt; 3. Mangel an synaptischen Bläschen; 4. desmosomenartige Verhaftungen zwischen Zellmembranen von Axon und intrafusaler Faser; 5. dyadenartige Anlagerungen des sarkoplasmatischen Retikulums an die Zellmembran der intrafusalen Faser im Bereich des synaptischen Spaltes. Nach unseren derzeitigen Vorstellungen sprechen diese Ultrastrukturmerkmale für eine rezeptorische Natur der beschriebenen Nervenendigungen.
    Notes: Summary In a rat muscle spindle transversally cut into a series of alternating semithin and ultrathin sections, two different forms of nerve terminations were found on two neighbouring nuclear chain fibres. The two nerve terminations were connected to the same group II nerve fibre and are consequently constituents of one particular secondary sensory ending. The nerve termination on one of the two nuclear chain fibres is of the anulo-spiral type. The nerve termination on the second nuclear chain fibre shows a number of axons lying closely together between plasma membrane and basement membrane of the intrafusal muscle fibre. Not all of these axons are in direct contact with the intrafusal fibre. The terminating nerve fibre seems to be divided into several branches of rather small diameters and irregular courses. It is suggested that this kind of termination could be a correlate of the so-called “flower spray” type of sensory endings in muscle spindles. The two morphologically different nerve terminations in the secondary ending have the following ultrastructural characteristics in common with those of the primary ending: 1) Synaptic contact between axon and intrafusal muscle fibre (synaptic gap about 200 Å) without interposition of basement membrane material; 2) terminal axons located beneath the basement membrane layer of intrafusal muscle fibres without covering by Schwann cells; 3) lack of synaptic vesicles; 4) desmosome-like structures between plasma membranes of axon and intrafusal muscle fibre, and 5) dyads of the sarcoplasmic reticulum adjacent to the synaptic cleft. According to present knowledge these features indicate that all of these endings are sensory ones.
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  • 20
    ISSN: 1432-0878
    Keywords: Rat ; Oocyte maturation ; in vitro studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After cultivation in a modified Trowell-system (organ ciilture) oocytes of 12- to 40-day-old rats were studied under the light and electron microscope. The cultivation period was 72 hrs. Egg cells from primary and early secondary follicles which are characterized by the lack of a zona pellucida and by one or at most two very large Golgi's complexes located near the nucleus do not show any alterations. The other egg cells are characterized by membrane packages which can otherwise only be observed in mature egg cells right before or after the ovulation. Meiotic processes or the formation of polar bodies are only seldom to be seen. These egg cells are surrounded by a thick zona pellucida. From these findings the following conclusions can be drawn: 1. In organ cultures meiotic processes are prevented by the inhibitory influence of follicle cells (Foote and Thibault, 1969). 2. A cytoplasmic maturation proceeds independently. 3. In-vivo an inhibitory factor influences the cytoplasmic maturation. This inhibition is not observed in the organ culture. Thus we can be sure that it develops outside the ovary. 4. The synthesis of the zona pellucida continues in-vitro.
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  • 21
    ISSN: 1432-0878
    Keywords: Heart muscle cells ; Electron microscopy ; Quantitative ; Asphyxia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Normale und hypoxische Herzmuskelzellen aus der Wand des linken Ventrikels der Ratte wurden quantitativ-morphologisch anhand von elektronenmikroskopischen Längsschnitten nach Perfusionsfixierung untersucht. In normalen Zellen waren alle Myofibrillen relaxiert, die mittlere Sarcomerlänge betrug 2,2 μm. Die Schnittfläche wurde zu 55% von Myofibrillen, zu 27% von Mitochondrien und zu 18% von Grundplasma und Reticulum eingenommen. Die zwischen den Myofibrillen liegenden Mitochondrien waren längsoval und im Mittel 2,3mal so lang wie breit. Es bestand kein Unterschied zwischen subendokardial und subepikardial gelegenen Zellen. 10 min nach Erstickung der Tiere waren in den sonst unauffälligen Muskelzellen die Glycogengranula vermindert. Nach 20 min führte die Hypoxie zu einer Zunahme der relativen Schnittfläche der Mitochondrien um etwa 16% und zu einer beginnenden Kontraktur der Myofibrillen (Sarcomerlänge 2,0 μm). 20 min Hypoxie in Hypothermie (25–30°C intrathorakal) veränderte die normale Zellstruktur dagegen kaum. Wenn die Herzen während der 20 min dauernden Hypoxie in Normothermie mit einer procainhaltigen sauerstoff- und glucosefreien Blutersatzlösung durchspült wurden, waren die Myofibrillen relaxiert, die Schwellung der Mitochondrien dagegen wurde nicht reduziert. 30 min nach Erstickung wurde die Kontraktur stärker (Sarcomerlänge 1,7 μm). Nach 60 min bildeten sich Superkontraktionsknoten, einzelne Myofibrillen waren in Höhe der I-Bänder unterbrochen. Die Cristae der Mitochondrien wichen auseinander, die Schnittfläche der Mitochondrien hatte um 27% zugenommen. Während in Normotherapie eine Asphyxie des Tieres bereits nach 10 min die Herzmuskelzellen funktionell schwer schädigt, ist die Schädigung morphologisch erst nach 20 min eindeutig. Das bedeutet, daß für die elektronenmikroskopische Präparation eine Hypoxie von unter 10 min bedeutungslos ist. Hinsichtlich der morphologischen Manifestationszeit für die Unterbrechung der Sauerstoffversorgung stimmen unsere Befunde an Herzmuskelzellen gut mit vergleichbaren Angaben an Leberzellen überein.
    Notes: Summary In heart muscle cells of the left ventricle of rats the distribution of cell organelles and their reaction to hypoxia were investigated by electron microscopy. In normal hearts fixed by perfusion with aldehydes, the mean sarcomere length was 2.2 μm. 27% of the longitudinal sectional area was occupied by mitochondria, 55% by myofibrils and 18% by sarcoplasmic reticulum and ground plasm. The mitochondria situated in rows between the fibrils were oval and measured 2.3 times more in length than in width. There was no difference between cells from subendocardial and subepicardial regions. 10 min hypoxia (complete occlusion of the trachea) did not affect the appearance of muscle cells but diminished the number of glycogen granules. After 20 minutes the area occupied by mitochondria was increased by 16%, the mitochondria between the myofibrils were more spherical and only 1.5 times longer than wide. The sarcomeres shortened to 2.0 μm. With hypothermia (25–30°C) hypoxia of 20 minutes duration did not affect the cell structure. Perfusion of the heart by a saline solution, which contained procaine but neither oxygen nor glucose, for 20 minutes prevented shortening of the sarcomeres but not swelling of the mitochondria. 30 minutes after occlusion of the trachea the myofibrils shortened to a sarcomere length of 1.7 μm. After 60 minutes irregularly and excessively contracted myofibrils appeared and some sarcomeres were interrupted at the level of the I-bands. In some of the swollen mitochondria the cristae were widely separated. The increase of the area occupied by mitochondria was 27%. Asphyxia affects heart muscle cells severely with respect to function within 10 min, but morphologically it takes 20 min before a definite effect can be noticed. As to the time after which lack of oxygen is manifested morphologically, our results are consistent with findings in liver cells.
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  • 22
    ISSN: 1432-0878
    Keywords: Subtotal Pancreatectomy ; Rat ; Islet Regeneration ; Excretory Duct System
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Männliche Ratten wurden bei einem Gewicht von 80–100 g subtotal pankreatektomiert (5% Rest) und zu verschiedenen Zeitpunkten nach der Operation abgetötet. Bei diesen wie bei unbehandelten Kontrolltieren wurde die Neubildung von Inselgewebe aus dem exkretorischen Gangsystem elektronenmikroskopisch untersucht. — Es konnte gezeigt werden, daß die Inselneubildung von Gangzellen ausgeht, welche ein auffallend helles Zytoplasma besitzen und samt ihren Kernen größer und abgerundeter sind als ihre Nachbarzellen. Diese Zellen wandern vom Lumen ab, wobei die entstehende Lücke zum Lumen zu jeweils durch eine seitliche Ausdehnung des Zytoplasmas benachbarter Gangzellen geschlossen wird. Die abgewanderten hellen Zellen, die mit den lichtmikroskopisch beschriebenen „trüben Zellen“ identisch sein dürften, haben die Fähigkeit, sich zu Alpha-oder Beta-Zellen zu differenzieren. Dabei werden sie größer und das Zytoplasma dunkler. Sie behalten aber gleichzeitig einige Besonderheiten, die auf ihre Herkunft hinweisen. Die Regeneration des Inselgewebes, die vorwiegend von den zentroacinären Zellen ausgeht, setzt bald nach der Operation stark ein, schwächt sich dann aber kontinuierlich ab. In den immer ineffektiver werdenden Regenerationsvorgang werden zunehmend größere Gangabschnitte einbezogen. Die weitgehende Erschöpfung der Regenerationsfähigkeit fällt mit dem Auftreten eines manifesten Diabetes zwischen dem 40. und 60. Tag p.op. zusammen.
    Notes: Summary Male rats were subtotally pancreatectomized at a weight of 80–100 g according to the method of Foglia (5% of the total pancreas remaining). The animals were killed at different intervals after. In these rats, as well as in healthy controls, the new formation of islets out of the excretory duct system was studied by electron microscopy. Obviously the new formation of islets takes origin from certain cells of the ductular system which show a light cytoplasm and are larger and rounder than their neighbouring cells. The latter goes for their nuclei, too, even to a larger degree. These light cells migrate away from the ductular lumen and the gaps resulting from this are closed by long and thin processes of the cytoplasm of their neighbouring duct cells coming in contact with each other. The cells having migrated away seem to have an ability to differentiate into alphaor beta-cells. Most probably they are identical with the “trübe Zellen” described by light-microscopists. The higher the degree of differentiation in these cells is, the darker becomes their cytoplasm. But they still keep for some time morphological aspects indicating their origin from ductular cells. An intense regeneration of islet tissue starts soon after the operation from the centroacinar cells but it decreases continuously after. As the process of islet regeneration becomes more and more ineffective, an increasing number of larger excretory ducts are involved in it. The exhaustion of the ability for regeneration is correlated exactly in time with the onset of a manifest diabetes between the 40 th and 60 th day after operation.
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  • 23
    ISSN: 1432-0878
    Keywords: C cells ; Thyroid ; Rat ; Ultimobranchial origin ; Differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Nos observations confirment l'origine ultimobranchiale des cellules C de la thyroïde du rat. L'évolution des corps ultimobranchiaux (C.U.B.) a été étudiée à partir du 16ème jour de gestation, stade où ils fusionnent avec l'ébauche thyroïdienne. Dès le 17ème jour, les premières cellules C se différencient dans le C.U.B. inclus dans la thyroïde. Au 18ème jour, elles sont plus nombreuses et commencent à se disperser dans les cordons thyroïdiens. La migration des cellules C est particulièrement importante au 19ème jour. A partir du 20ème jour, les signes d'activité sécrétoire s'intensifient très nettement. A la fin de la vie foetale, les cellules C sont comparables aux cellules C adultes. La differenciation des cellules parathyroïdiennes précède nettement celle des cellules C.
    Notes: Summary Our observations confirm the ultimobranchial origin of the C cells of the rat thyroid. We studied the development of the ultimobranchial body from the 16th day of pregnancy, when there is fusion with the thyroidian anlage, onwards. As early as the 17th day, the first C cells differentiate in the ultimobranchial body which is included into the thyroid. On the 18th day, they are more numerous and start to scatter throughout the thyroidian cords. The migration of the C cells is especially obvious on the 19th day. From the 20th day onwards, there is marked increase in secretory activity. At the end of the foetal life, the C cells resemble those of the adult. The differentiation of the parathyroid cells significantly precedes that of the C cells.
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  • 24
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Monoamine fluorescence ; Output of pars distalis hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of monoamines in the median eminence of foetal, neonatal and adult rats has been studied with the Falck-Hillarp fluorescence histochemical technique in preparations in which the hypothalamus and pituitary gland were in continuity. In adult rats monoamine fluorescence is present throughout the median eminence, including the anatomical stem. In foetal rats a few sagittally-directed varicose fluorescent fibres are seen in the median eminence. In neonatal rats palisade layer fluorescence in appreciable amounts is first seen on the fourth day in the region of the anatomical stem. By the eighth day it has spread throughout the palisade layer of the entire median eminence, and by the end of the third week it has attained adult intensity. The appearance of monoamines in the median eminence, the development of a functional hypophysial portal system, and a changing pattern of development of function in both the hypothalamo-pituitary-adrenal and hypothalamo-pituitary-thyroid axes thus all appear to be contemporaneous events. It is suggested that the monoamines of the median eminence represent part of a neural system influencing the output of pars distalis hormones, in particular of ACTH and TSH secretion.
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  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 104 (1970), S. 572-581 
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Rat ; Cellular Localization of 3H-Oestradiol ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The hypothalamus of male and female rats, given 0.3 μg/100 g body weight of 6.7-3H-oestradiol-17β and killed 1 hour after the injection, was examined by autoradiography in order to 1) localize the areas and the cells involved in the uptake of the hormone, and 2) study the intracellular localization of the labelled material. Only nerve cells contained radioactive material while glial and ependymal cells were not significantly labelled. In the anterior hypothalamus, labelled nerve cells were concentrated in areas corresponding to nucleus preopticus medialis and nucleus preopticus, pars suprachiasmatica. The nucleus supraopticus was unlabelled. In the medial basal hypothalamus, neurons corresponding to the nucleus arcuatus and the lateral part of the nucleus ventromedialis showed marked labelling. No significant labelling was observed in the nucleus paraventricularis, pars magnocellularis. Although the individual nerve cells varied in their extent of labelling, the major proportion of the silver grains were consistently concentrated over the nuclei. Castration was not found to influence the results. The findings were essentially the same in male and female rats and appear to suggest that oestradiol exerts a direct effect on nerve cells in certain hypothalamic areas.
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  • 26
    ISSN: 1432-0878
    Keywords: Thymus ; Rat ; Involution ; Histochemical pattern
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Makrophagen und entodermale Retikulumzellen samt Ausläufern lassen sich im Thymus der Wistar-Ratte durch den histochemischen Nachweis der sauren Phosphatase und der unspezifischen Esterase selektiv darstellen, während die Lymphozyten nicht reagieren. Häufigkeit und Verteilung der Retikulumzellen und Makrophagen lassen altersabhängige Unterschiede erkennen: Auf Kosten der Retikulumzellen nimmt die Zahl der Makrophagen mit fortschreitendem Lebensalter zu. Bei geschlechtsreifen Tieren bilden sie einen Wall an der Mark-Rinden-Grenze. Die Bedeutung der sauren Phosphatase in entodermalen Retikulumzellen wird unter der Annahme diskutiert, daß es sich um lysosomengebundenes Ferment handelt. Lysosomen sind im involvierenden Thymus wahrscheinlich an autolytischen oder phagozytotischen Prozessen beteiligt. Es stellt sich die Frage, ob Lysosomen in entodermalen Retikulumzellen des Thymus neugeborener Tiere in die Abgabe einer humoral wirksamen Substanz eingreifen können.
    Notes: Summary Macrophages and entodermal reticulum cells in the thymus of Wistar rats contrast by their rich contents of acid phosphatase and unspecific esterase activity with the negativ reacting lymphocytes. Frequency and distribution of the cells vary according to different stages of age: at cost of the entodermal reticular cells the number of macrophages increases with progressive age. In sexually mature animals they form a typical layer at the corticomedullary junction. The functional meaning of acid phosphatase in the entodermal reticulum cells is discussed under the assumption that this enzyme is lysosomebound. In the involuting thymus lysosomes are involved in autolytic or phagocytic processes. The question arises wether lysosomes in entodermal reticulum cells in the thymus of newborn animals can take part in the control of an humoral function of the thymus.
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  • 27
    ISSN: 1432-0878
    Keywords: Anterior hypophysis ; Hypothalamus ; Rat ; Uptake of 3H-Oestradiol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anterior hypophysis and hypothalamus of male and female rats given 3H-oestradiol were examined with regard to 1) the kinetics of the uptake of the radioactive material, 2) the chemical nature of the labelled material, and 3) the influence of non-labelled oestradiol-17β, oestradiol-17α and testosterone on the uptake of 3H-oestradiol. The anterior hypophysis was found to concentrate and retain oestradiol in basically the same manner in male and female rats. The pattern of the uptake was similar to that of the uterus and vagina, with a concentration peak 2 hours after the injection. Non-target tissues such as cerebral cortex, liver and blood attained their maximum uptake already 15 minutes after the injection. Thereafter the concentration gradually decreased. The ratio between the concentration of labelled material in the anterior hypophysis and brain cortex gradually increased until a peak was reached at 8 hours in both sexes. In the female, the concentration of labelled material in the anterior hypophysis was then 106.3 times greater than in the brain cortex, while in the male the ratio was 63.2. In the hypothalamus the uptake followed a pattern similar to that of the brain cortex. However, in the former the concentration of labelled material was consistently greater than in the latter. At maximum uptake, registered 4 hours after the injection, the concentration was about two times greater in the hypothalamus than in the cerebral cortex. The neurohypophysis contained, on an average, 1/6 of the amount of radioactive material registered in the anterior lobe one hour after the injection, but it was about two times greater than in the brain cortex. Isolation and identification of the radioactive material in the anterior hypophysis and hypothalamus showed that in both sexes nearly all of it was chemically unchanged oestradiol. Graded doses of non-labelled oestradiol-17β were found to decrease the uptake of 3H-oestradiol in the anterior hypophysis and hypothalamus almost linearly, while the concentration of labelled material in the brain was unaltered. Oestradiol-17α and testosterone were without significant effect on both the pituitary and hypothalamic accumulation of 3H-oestradiol. Therefore, a limited number of binding sites, with a high degree of specificity for oestradiol, appear to exist in both tissues. The results were essentially the same in male and female rats.
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  • 28
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Deafferentation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This report concerns a light and electron microscopic investigation of the median eminence and dorsal infundibular stem of the rat following surgical isolation (deafferentation). Using a modification of the Halász technique, the basal hypothalamus, including the arcuate nucleus and median eminence were surgically isolated from surrounding structures. Special attention was directed to the contact (external) zone of the median eminence and rostral infundibulum where tuberohypophyseal axons as well as ependymal cell processes abut upon the abluminal basement membrane of the portal perivascular space. The results of this study to date suggest that 9, 20, and 40 days following surgical isolation, there is a distinct increase in the population of tuberohypophyseal dense core vesicles. It is suggested that deafferentation abolishes inhibitory and excitatory input that serves to modify the cellular dynamics of tuberohypophyseal neurosecretory elements. Comments are also made on the presence of cistern-like structures in the lateral median eminence; the presence of vesicle-like inclusions in terminal ependymal processes is discussed in relationship to the role that ependyma may play in linking the third ventricle with the adenohypophysis.
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  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 104 (1970), S. 597-614 
    ISSN: 1432-0878
    Keywords: Hypophysis ; Rat ; Localization of 3H-Oestradiol ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pituitaries of male and female rats given 0.3 μg of 6.7-3H-oestradiol-17β per 100 g body weight were examined by autoradiography in order to 1) identify the cells responsible for the uptake of the hormone, 2) determine the intracellular distribution of the hormone and quantify the proportions localized within the cytoplasm and nucleus by silver grain counting, and 3) see if sex differences existed in the cellular and intracellular distribution of the hormone. The animals were killed at intervals varying from 1 minute to 8 hours following intravenous or intramuscular injection. A large proportion of pituitary cells having the morphologic characteristics of acidophils, basophils and chromophobes contained radioactive material. Castration cells and acidophils of gonadectomized and lactating rats showed marked labelling. In male and female rats killed 10 minutes after intravenous injection, 84.4 and 83.6 per cent of the cells were labelled. One hour after intramuscular injection, 86.6 and 76.1 per cent of the cells were labelled in males and females, respectively. Thus, a small proportion of the cells remained unlabelled. Labelled cells showed silver grains both in the cytoplasm and over the cell nuclei, but the major proportion of the radioactive material was invariably associated with the cell nuclei in all cell types and at all time intervals. About 65 per cent of the radioactive material was associated with the cell nuclei in animals killed five minutes or one hour after intravenous or intramuscular injection of the hormone. The silver grains appeared to be randomly distributed in both the cytoplasm and over the cell nuclei. In the intermediate lobe and the neurohypophysis, only sparse labelling with random distribution was observed. At the border between the intermediate lobe and the neurohypophysis, labelling of single cells or clusters of cells similar to those in the adenohypophysis was found. The results, which were essentially the same in male and female rats, appear to indicate a direct effect of oestradiol at the pituitary level.
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  • 30
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Rat ; Vasopressin release ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Le lobe postérieur de l'hypophyse a été examiné sur coupes ultrafines chez 45 rats (24 normaux, 17 déshydratés respectivement 1, 2 et 4 jours, et 4 anesthésiés à l'éther), après fixation au glutaraldéhyde ou selon la méthode de Karnovsky, post-fixation osmiée et double contraste à l'acétate d'uranyle et au citrate de plomb. Des fibres neurosécrétoires sombres et claires sont reconnaissables, mais les données manquent encore pour interpréter cette différence. Des densifications juxta-membranaires sont observées dans les terminaisons neurosécrétoires là où se trouvent des amas de microvésicules. Des fibres neurosécrétoires traversent parfois des pituicytes; il est aussi souvent observé des fibres, chargées de granules, libres dans un espace péricapillaire. Les espaces péricapillaires, ramifiés en tous sens loin des vaisseaux, développent une large surface de contact avec les extrémités nerveuses et les prolongements de pituicytes. Dans des conditions techniques bien contrôlées, la déshydratation n'entraîne pas de modifications appréciables des granules de neurosécrétat après 24 h. Ensuite les granules sont diminués en nombre, de façon très considérable le 4e jour; mais les granules restants ont un contenu dense normal; jamais il n'a été observé d'aspects de ≪granules vides ≫. Après anesthésie prolongée à l'éther, il n'y a aucune modification visible ni du nombre, ni de la densité des granules. Ces observations sont discutées quant au mécanisme de l'excrétion de vasopressine; elles sont en faveur de l'existence de deux pools hormonaux, l'un libre et rapidement disponible, l'autre plus fortement lié et certainement contenu dans les granules jouant le rôle de réserve. Toutefois un mécanisme d'exocytose granulaire ne peut être formellement exclu.
    Notes: Summary Hypophysial neural lobes of 45 rats (24 controls, 17 dehydrated resp. 1, 2 and 4 days, and 4 ether anesthetized) were fixed either with glutaraldehyde or according to Karnovsky and post-fixed in osmium tetroxyde; ultrathin sections were stained by uranyl acetate and lead citrate. Dark and clear neurosecretory fibres were observed, but sufficient data are still lacking for a valuable interpretation of these aspects. Juxta-membraneous densifications are visible in limited areas of neurosecretory terminals where clusters of microvesicles are present. Neurosecretory fibres happen to be completely encircled by pituioyte cytoplasm; fibres loaded with elementary granules are frequently encountered running free in a pericapillary space. Pericapillary spaces stretch out branching far away from vessels, resulting in a widespread contact with nerve terminals and pituicyte processes. In accurately controlled technical conditions, dehydratation does not result in any noticeable change of neurosecretory granules after 24 h. A decrease of the number of granules follows and is extremely conspicuous after 4 days; though, remaining granules keep a normal dense content, and aspects of “empty granules” have never been observed. After prolonged ether anesthesia, no visible change either in number or electron density of granules was observed. These findings are discussed in consideration of the mechanism of vasopressin release; they support the hypothesis of two hormonal pools, one of which would be free and rapidly available for release, the other being more tightly bound and certainly located in granules representing a storage site. Though granular exocytosis cannot be absolutely excluded.
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  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 108 (1970), S. 487-500 
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Residual lumen ; Epithelial cells ; Fine structure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histology, enzyme histochemistry, and electron microscopy of the epithelium covering the rat pituitary residual lumen was studied. The anterior and posterior epithelium have similar histological and histochemical appearance, although the posterior epithelium shows stronger enzyme reactions for an esterase and many dehydrogenases. Electron microscopic studies reveal that both epithelia form a continuous lining. Anterior epithelium is in immediate contact with the interstitial spaces of the anterior lobe, while the posterior epithelium is separated from the intermediate lobe by a continuous basement lamina. The cytological features of both epithelia are also remarkably similar with scanty rough-surfaced endoplasmic reticulum, inconspicuous Golgi apparatus, round or oval mitochondria, and moderate number of lysosomal bodies. The apical surface of these cells is covered by microvilli and in some, especially posterior epithelial cells, by numerous cilia. Anterior epithelial cells and the apical portions of the posterior epithelial cells contain a number of large vacuoles with material possibly related to the colloid within the residual lumen. Electron microscopic findings suggest that both epithelia are possibly active in transfer and/or disposal of the colloid material rather than being secretory themselves. Enzyme histochemical findings support the hypothesis of an active role of these cells in metabolic processes related to phagocytosis. Based on these observations the colloid seems to be the product of the anterior lobe function.
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  • 32
    ISSN: 1432-0878
    Keywords: Cerebral cortex ; Synapses ; Rat ; Postnatal differentiation ; Morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of layers I and II of the motor cerebral cortex of rat brain has been studied at birth, 4, 7 and 14 days postnatal and in the adult. Compared with the adult, neonatal rat motor cortex exhibited a large extracellular space which decreases with increasing age. At all stages studied the neurons were seen to contain the organelles usually found in adult neurons. Growth cones were present in decreasing numbers up to 14 days old. Synapses were detectable at birth and there was an obvious increase in their number throughout the postnatal development. At the earliest stages studied there was a lack of specialization characteristic of the adult. Many synapses were either avesicular or relatively so and lacked the high degree of modification of adult pre- and postsynaptic membranes. By 7 days after birth many synapses existed which in all morphological respects resembled those of the adult, and by 14 days, the majority were of the adult type. These findings, particularly with reference to the postnatal development of synapses, have been discussed in relation to the known electrophysiological findings.
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  • 33
    ISSN: 1432-0878
    Keywords: Cerebral cortex ; Rat ; Synapses ; Postnatal ; Quantitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitation of synapses at different postnatal ages has been undertaken in the cerebral cortex of the rat. In this study axial ratios of presynaptic bags, proportion of cortex occupied by presynaptic bags and numbers of synapses per unit volume of cortex have been estimated. Observations on synaptic vesicle packing densities have also been made. Synaptic bags become increasingly spherical up to 7 days of age and become more elongated thereafter. The proportion of cortex occupied by presynaptic bags increases rapidly up to 7 days of age and then at a decelerated rate up to maturity. The number of synapses per unit volume increases slowly over the first four days after which there is a rapid increase to 14 days, followed by a decelerated rate. The average presynaptic bag shows marked changes in volume with increasing age which indicate the probability of two stages of synaptic development. This two stage development is further reflected in the estimates on vesicle packing densities. The implications of the results are discussed in relationship to changes in functional activity of the cortex during postnatal development.
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  • 34
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 35
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Information on physical and chemical properties, especially on the structure and chemical bonding of M[FeCl4]-complexes has been obtained by measurements of the optical absorption, the MÖSSBAUER effect and EPR. (M stands for a monovalent cation.) The iron(III) chlorocomplex compounds Ag[FeCl4], Rb[FeCl4] and Li[FeCl4] have been proved to exist within the systems MCl—FeCl3 by measurements of optical spectra and EPR.
    Notes: Durch optische Absorptionsmessungen, MÖSSBAUER- und EPR-Untersuchungen werden Ergebnisse über die physikalischen und chemischen Eigenschaften, die Struktur und die Bindungsverhältnisse in M[FeCl4]-Komplexen erhalten. Bei diesen Untersuchungen konnten die Komplexverbindungen Ag[FeCl4], Rb[FeCl4] und Li[FeCl4] mittels einer EPR-Methode bzw. optischer Absorptionsmessungen nachgewiesen werden.
    Additional Material: 3 Ill.
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  • 36
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: By electrolytical reduction of solutions of TiCl4 in methanol blue solutions of TiCl3 were obtained from which the crystalline adducts TiCl3 · 4 CH3OH and TiCl3 · 5 CH3OH were isolated. These solids were used as starting material for the preparation of other TiCl3 complexes. By exchange of ligands blue TiCl3 · 3 DMF was obtained which in vacuo could be thermally decomposed to green TiCl3 · 2 DMF. The thermal decomposition of TiCl3 · 3 THF was newly studied. Magnetic susceptibilities, infrared and electron spectra were measured.
    Notes: Durch elektrolytische Reduktion von TiCl4 in Methanol wurden blaue TiCl3-Lösungen erhalten, aus denen die kristallinen Addukte TiCl3 · 4 CH3OH und TiCl3 · 5 CH3OH isoliert werden konnten. Diese dienten als Ausgangsmaterial zur Präparation anderer TiCl3-Komplexe. Durch Ligandenaustausch wurde blaues TiCl3 · 3 DMF erhalten, das sich im Vakuum thermisch zu grünem TiCl3 · 2 DMF abbauen ließ (DMF = Dimethylformamid). Der thermische Abbau von TiCl3 · 3 THF wurde neu untersucht. Magnetische Suszeptibilitäten, Infrarot- und Elektronenspektren wurden gemessen.
    Additional Material: 1 Ill.
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  • 37
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complexes of the formula Cu2X3 (OR)(N∩N)2 [X = Cl, Br; R = H, CH3; N∩N = bidentate amineligand] are described, their magnetic and spectrophotometric properties are discussed and the possible structures deduced.
    Notes: Es werden Komplexe der Bruttozusammensetzung Cu2X3(OR) (N∩N)2 [X = Cl, Br; R = H, CH3; N∩N = zweizähliger Aminligand] beschrieben, ihr magnetisches und spektrales Verhalten diskutiert und mögliche Strukturen abgeleitet.
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  • 38
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 372 (1970), S. 106-112 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The systems LaP/P and CeP/P were investigated. Polyphosphide phases with the compositions LaP1.6-2.5 (A), LaP3.5-5.3(B), LaP5.8-9.0(C) and LaP6.5-8.9(D), respectively, as well as CeP1.7-2.4 (A′), CeP3.5-6.5(B) CeP6.5-9.0(C) and were found. The phases B and C of lanthanum and cerium are isotypic, but not the phases A and A′. The phases C and D of lanthanum are different modifications with approximately equal homogenity ranges.
    Notes: Es wurden die Systeme LaP/P und CeP/P untersucht. Dabei wurden Polyphosphidphasen der Zusammensetzung LaP1,6-2,5 (A), LaP3,5-5,3 (B) LaP 5,8-9,0 (C) bzw. LaP6,5-8,9 (D), sowie CeP1,7—2,4 (A′), CeP3,5-6,5 (B) und CeP6,5-9,0(C) gefunden. Die Phasen B und C beim Lanthan und Cer sind isotyp, dagegen nicht die Phasen A und A′. Die Phasen C und D beim Lanthan sind verschiedene Modifikationen mit annähernd gleichem Homogenitätsbereich.
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  • 39
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 372 (1970), S. 119-126 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: For the alkali fluorosulfates MSO3F infrared spectra (M = Li, Na, K, Rb, Cs) and also RAMAN spectra (M = K, Rb, Cs) have been recorded. The results are discussed to get some information about the lattice structures. The C3 axis of the anion has several possibilities of orientation in the unit cell for the salts with heavy cations.
    Notes: Die Infrarotspektren der Alkalifluorosulfate MSO3F sowie die Raman-Streuung für M = K, Rb und Cs wurden aufgenommen. Die Ergebnisse werden diskutiert und zu einigen Aussagen über die Gitterstrukturen benützt. Die dreizählige Achse des Anions bei den schwereren Salzen besitzt mehrere Orientierungsmöglichkeiten in der Einheitszelle.
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  • 40
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 372 (1970), S. 134-143 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The stability constants of the copper complexes of acetoacetdialkylamides and substituted acetoacetanilides have been determined by potentiometric pH-measurements. The variation of stability constants with phenyl substituents is interpreted.
    Notes: Die Stabilitätskonstanten der Kupferchelate von Acetessigsäuredialkylamiden und substituierten Acetessigsäureaniliden wurden durch potentiometrische Bestimmung der Wasserstoffionenkonzentration ermittelt. Der Einfluß der Substituenten am Phenylring auf die Stabilität der Komplexe wird durch induktive, mesomere und sterische Effekte erklärt. Die größere Stabilität der Kupferkomplexe mit Acetessigsäuredialkylamiden wird darauf zurückgeführt, daß die Resonanz des Chelatringsystems nicht wie bei den Acetessigsäureaniliden durch ein zweites Resonanzsystem gestört wird.
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  • 41
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The stability constants of the copper complexes of acetoacet-2-amidopyridine and-2-amidopyrimidine have been determined by potentiometric pH-measurements. The variation of stability constants with pyridyl and pyrimidyl substituents is interpreted.
    Notes: Die Stabilitätskonstanten der Kupferchelate von Acetessigsäure-2-amidopyridinen und -pyrimidinen werden durch potentiometrische Bestimmung der Wasserstoffionenkonzentration ermittelt, Der Einfluß der Substituenten am Pyridin- bzw. Pyrimidinring wird diskutiert und die Abstufung der Komplexstabilitäten durch die unterschiedliche Konjugation des π-Elektronensystems des Rings mit dem Chelatringsystem erklärt.
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  • 42
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: This paper contains: 1The synthesis of the 1.3-disilacyclopentenes (a)(b)(2) and of the 1.3-disilacyclo-butane (c); formulas see above.2The synthesis of the 1.3-disilacyclopentane skeleton (d) and of the SiCl-functional derivatives (e) (f ) (g) (h) (i) as well as of SiH-containing derivatives, e.g. (j).3The chlorination of (i) with SO2,Cl2, yielding (k) and (l), and the formation of (m) from (k) with K-methypyrrolidine.4The synthesis of the spirane (n).5The synthesis of the ten-membered ring(o) and of the unsaturated derivatives (p)and (q). Besides the synthetic routes, spectroscopic data (ir, pmr, and mass spectra) of the cyclic compounds as well as of the intermediate products are given.
    Notes: Es wird berichtet über: 1Die Synthese der 1,3-disilacyclopentene (a) (b)2 und des 1,3-disila-cyclobutans (c) 2Die Synthese des 1,3-Disilacyclopentan-Gerüstes (d) und der SiCl-funktionellen Derivate (e)(f)(g)(h)(i)sowie der SiH haltigen Derivate, z. B. (j) 3Die Chlorierung von (i) mit SO2Cl2 zu (k) und (1) und die Bildung ron (m) aus (k) mit K-Methylpyrrolidin 4Die Synthese des Spirans (n) 5Die Synthese des 10-Ringes (o) und der nngesattigten Derivate (p) und (q). SeFen den Synthesewegen werden spelitroskopische Daten und PMR-Spektren der cyclischen Verhindungen sou ie der Zwischenprodukte angegeben.
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  • 43
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 372 (1970), S. 74-78 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The phase diagram of the condensed system Br2—N2O4 has been reinvestigated with increased accuracy. The results of this study and comparison with the melting points of NO2F and NO2Cl lead to a new interpretation of the observable unstable state. It seems to indicate N2O4-rich mixed crystals or some metastable modification of N2O4 rather than an eutectic NO2Br—N2O4.
    Notes: Für das kondensierte System Br2—N2O4 wurde das Zustandsdiagramm erneut and mit erhöhter Genauigkeit untersucht. Das Ergebnis dieser Untersuchung und ein Vergleich mit den Schmelzpunkten von NO2F und NO2Cl führen zu einer neuen Deutung des beobachtbaren instabilen Zustandes. Dieser Zustand scheint eher anf N2O4-reiche Mischkristalle oder eine instabile N2O4-Modifikation hinzuweisen als auf ein Eutektikum NO2Br—N2O4.
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  • 44
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of phosphobenzene (phenylpolyphosphine A) with various amounts of phenyllithium give l,4-dilithio-l,2,3,4-tetraphenyl-tetraphosphine, tetraphenyldiphosphine, l,3-dilithio-l,2,3-triphenyltriphosphine, 1-lithio-l,2,2-triphenyl-diphosphine, 1,2-dilithio-diphenyldiphosphine and, after cleavage of all P—P bonds, lithium-diphenylphosphide, dilithio-phenylphosphide and triphenylphosphine. Formation and reactions of the products are discussed.
    Notes: Reaktionen von Phenylpolyphosphin A mit kleinen Mengen Lithiumphenyl führen zunächst zu 1,4-Dilithium-l,2,3,4-tetraphenyl-tetraphosphin, Tetraphenylbiphosphin und 1-Lithium-l,2,2-triphenyl-biphosphin. Durch schrittweise Erhöhung der LiC6H5-Konzentration können als weitere Zwischenprodukte 1,3-Dilithium-1,2,3-triphenyl-triphosphin und 1,2-Dilithium-diphenyl-biphosphin nachgewiesen werden. Nach Spaltung aller P—P-Bindungen liegen neben dem Hauptprodukt Lithium-diphenyl-phosphid wenig Dilithium-phenylphosphid und Triphenylphosphin vor. Bildung und Umsetzung der Substanzen werden durch Aufstellung einer Reihe abnehmenden elektrophilen Verhaltens interpretiert.
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  • 45
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 372 (1970), S. 87-99 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The crystal structures of BaSi2, SrSi2 and of a new modification of CaSi2 are described. The Si arrangements in these structures are discussed. There are Si4 tetrahedrons in BaSi2, a Sin threedimensional framework in SrSi2 and twodimensional corrugated sheets of Si hexagons in CaSi2.
    Notes: Die Kristallstrukturen von BaSi2 und SrSi2 werden beschrieben. Von CaSi2 wurde eine neue Modifikation aufgefunden. Die in den 3 Phasen nachgewiesenen Si-Verbände (Si4-Tetraeder im BaSi2, Sin-Raumnetzgerüst im SrSi2 und Sin-Schichten im CaSi2) werden vergleichend diskutiert.
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  • 46
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 47
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The electronic absorption spectra of the ions PS43-, AsS43- and SbS43- have been measured in aqueous solution. The transitions are assigned and discussed, using a simple MO diagram.
    Notes: Es wurden die Elektronenspektren von PS43-, AsS43- und SbS43- in wäßriger Lösung gemessen. Alle Ionen weisen unterhalb von 54 kK lediglich eine starke Bande auf. Die Banden werden an Hand eines stark vereinfachten MO-Schemas zugeordnet. Es läßt sich zeigen, daß bei den oben erwähnten Ionen praktisch keine π-Bindungen vorliegen.
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  • 48
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sodium bromite may be prepared by dismutation of hypobromite solution produced by the addition of bromine to concentrated caustic soda at 0 °C, the hypobromite being destroyed after the maximum bromite concentration has been reached. Using bromine water or bromine vapour diluted by nitrogen at low temperatures, it is possible to prepare bromite-free hypobromite solutions.
    Notes: Eine aus Brom und Natronlauge hergestellte Natriumhypobromitlösung wird zur Darstellung des Natriumbromits durch Disproportionierung benutzt. Das im Maximum der Bromitkonzentration vorhandene Hypobromit muß zerstört werden.Mit Bromwasser oder stickstoffverdünnten Bromdämpfen kann bei niedrigen Temperaturen eine bromitfreie Hypobromitlösung hergestellt werden.
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  • 49
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 372 (1970), S. 150-161 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The crystal structure of CuBr · (C2H5)4P2 has been determined by single crystal X-ray methods. The crystals are triclinic (space group P 1) with two formula units per unit cell (a) = 9,29, b = 9,92, c = 7,57 Å, α = 85,3°, β = 106,6°, γ = 109,1°. The copper atoms are tetrahedrally coordinated by two bromine and two phosphorus atoms (of different biphosphine molecules). The structure has continuous chains running parallel c, in which the copper atoms are linked together by alternating double bridges consisting of two biphosphine molecules and two bromine atoms, respectively.
    Notes: Die Kristallstruktur von CuBr · (C2H5)4P2 wurde röntgenographisch aus Einkristallaufnahmen bestimmt. Die Verbindung kristallisiert in der Raumgruppe P 1 mit den Gitterkonstanten a = 9,29 Å, b = 9,92 Å, c = 7,57 Å, α = 85,3°, β = 106,6°, γ = 109,1° und 2 Formeleinheiten in der Elementarzelle. Die Cu-Atome besitzen tetraedrische Umgebung und werden abwechselnd über Doppelbrücken aus 2 Bromatomen bzw. 2 Biphosphinmolekülen miteinander verknüpft, auf diese Weise entstehen unendliche Ketten parallel der c-Achse.
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  • 50
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The influence of sulphur containing substances on the formation of iron, molybdenum and nickel carbonyl has been investigated. Under tribomechanical treatment, these reactions proceed already at normal conditions, sulphur and S-containing compounds catalysing the carbonylisation. This sensibilisation effect is due according to kinetical and thermodynamical measurements- to the formation of S-containing intermediates, lowering the apparent activation energy of the nickel carbonyl formation from 13.1 to 6.4 kcals/mole. The influence of H2S on the carbonylisation of industrial products was studied.
    Notes: Es wurde der Einfluß schwefelhaltiger Substanzen auf die Bildung von Eisen-, Molybdän- und Nickelcarbonyl untersucht. Unter Bedingungen der tribomechanischen Bearbeitung verlaufen diese Reaktionen bereits unter Normalbedingungen, wobei Schwefel und schwefelhaltige Verbindungen die Carbonylisierung dor Metalle katalytisch beschleunigen. Nach kinetischen und thermodynamischen Messungen beruht der sensibilisierende Effekt auf der Bildung von schwefelhaltigen Zwischenverbindungen, unter deren Mitwirkung für die Nickelcarbonylbildung die scheinbare Aktivierungsenergie der Reaktion von 13,1 auf 6,4 kcal/mol sinkt. Der sensibilisierende Einfluß von H2S auf die Carbonylisierung technischer Produkte wurde untersucht.
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  • 51
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Adsorption of various acids on anatase of high surface area was studied. Phosphoric, arsenic, sulphuric and acetic acid are specifically adsorbed; hydrochloric and perchloric acid are not adsorbed. Phosphate ions are bound on the TiO2 surface also from NaH2PO4 and Na2HPO4 solutions; sodium ions are adsorbed at the same time. OH- ions on the surface are replaced by anions such as H2PO4- in these reactions. The bonding of adsorbed phosphate ions is not purely ionic. Infrared spectra show that adsorbed acetic acid is bound as acetate. NO2 reacts with the basic OH- ions undergoing disproportionation; OH- ions are replaced by NO3- ions.Phophoric acid adsorption corresponded always to half the total OH population on five different TiO2 samples. The TiO2 surface is not completely covered by OH groups. The maximum coverage is ca. 7.5 μMol OH/m2.
    Notes: Die Adsorption verschiedener Säuren an einem feinteiligen Anatas wurde untersucht. Vor allem Phosphorsäure, Arsensäure, Schwefelsäure und Essigsäure werden spezifisch adsorbiert. Salzsäure und Perchlorsäure werden nicht adsorbiert. Phosphat-Ionen werden auch aus NaH2PO4- und Na2HPO4 -Lösung gebunden; zugleich werden Natriumionen adsorbiert. Bei diesen Reaktionen werden OH- -Ionen der TiO2-Oberfläche durch Anionen, z. B. H2PO4--Ionen, ersetzt. Die Bindung der adsorbierten H2PO4--Ionen ist nicht rein ionisch. Adsorbierte Essigsäure liegt als Acetat vor, wir das Infrarotspektrum zeigt. NO2 reagiert mit den basischen OH--Ionen der Oberfläche unter Disproportionierung; dabei werden die OH--Ionen durch NO3- ersetzt.Bei fünf untersuchten TiO2 -Präparaten entspricht die Phosphorsäure- Adsorption jeweils der Hälfte des gesamten Gehaltes an OH-Gruppen. Nur ein Teil deer Oberfläche ist mit OH-Gruppen belegt. Die maximale Belegungsdichte beträgt etwa 7,5 μMol OH/m2.
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  • 52
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The ternary disilicides of group-II elements Ca1-xSrxSi2 und Sr1-xBaxSi2 are prepared and crystallographically investigated. In the quasibinary system CaSi2—SrSi2 the structures of the Ca-rich phases can be described as stacks of twodimensional corrugated sheets of Si hexagons. The phases Sr1-xBaxSi2 with X = 0.2 to X = 1.0 crystallize in the structure type of BaSi2 with isolated Si4 tetrahedrons. There in no miscibility between CaSi2 and BaSi2 in the solid phase.
    Notes: Die ternären Erdalkalidisilicide der Stöchiometrie Ca1-xSrxSi2 und Sr1-xBaxSi2 wurden dargestellt und röntgenographisch charakterisiert. Im quasibinären Schnitt CaSi2—SrSi2 wurden im Ca-reichen Teil Phasen erhalten, deren Strukturen sich als Stapelvarianten mit zweidimensionalen, gewellten Si-Sechsecknetzen erwiesen. Im System Sr1-xBaxSi2 tritt der Strukturtyp des BaSi2 mit isolierten Si4-Tetraedern von x = 0,2 bis x = 1,0 auf. Der quasibinäre Schnitt BaSi2—CaSi2 entspricht dem Zustandsdiagramm eines Zweistoffsystems ohne Mischkristallbildung.
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  • 53
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Durch Umsetzung von zinkacetylacetonat mit substituierten Pyridinen und Chinolinen wurden elf Neutralkomplexe mit Fünferkoordination, [Zn(acac)2L], dargestellt.
    Notes: Zinc acetylacetonate was reacted in methanolic medium with substituted pyridines and quinolines, and eleven non-electrolytic, pentacoordinated mixed-ligand complexes [Zn(acac)2L] have been isolated and characterised. The infra-red spectra indicate the presence of both acetylacetone and the bonded ligand.
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  • 54
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 55
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Es wurde die Substitution von Halogenid durch Hydroxid bei einigen Halogenopentamminkobalt(III)- und -chrom(III)-Kationen in wäßrigem Dioxan bei Alkalikonzentrationen bis zu 0.1 M untersucht. Bei überschüssigem OH- (konstante Ionenstärke) wurden Geschwindigkeitskonstanten nach scheinbar erster Ordnung ermittelt. Es ist eine dem Gleichgewicht vorgelagerte Ionenpaar-Assoziation angezeigt, wobei aber nicht über die Art der Weiterreaktion des Ionenpaares - Direktaustausch oder Protonenabzug - entschieden werden kann. Bei CoIII ist die Ionenpaarbildung Stärker als bei CrIII; sie nimmt mit steigendem Dioxangehalt zu.
    Notes: The replacement, by hydroxide ion, of the coordinated halide from some halogenopentamminecobalt(III) and -Chromium(III) cations in aqueous dioxan has been studied over a range of alkali concentrations up to 0.1 M. With excess of hydroxide ion at constant ionic strength, pseudo first-order rate constants were obtained. The results support a pre-equilibrium association of complex and hydroxide ions in these media, but do not provide distinction as to whether the resulting ion-pair subsequently reacts by direct exchange or by proton removal. The extents of ion association are found to be greater for the cobalt(III) than for the chromium(III) system, increasing with the amount of dioxin in the solvent mixture.
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  • 56
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Single crystals of the system CdCr2(S1-xSex)4 have been prepared by chemical transport with I2/AlCl3 mixtures and by flux growth from solutions in molten CdCl2.
    Notes: Im System CdCr2(S1-xSex)4 wurden Einkristalle durch Transportreaktion mit J2/AlCl3-Gemischen als Transportmittel und durch Kristallisation aus CdCl2-Schmelzlösungen hergestellt.
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  • 57
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 58
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The transformation of vapour-deposited α-CuPc films into the β-phase, occuring when the films are heat-treated, is investigated by means of IR spectroscopy. X-ray diffraction and electron microscopy. The absorbance at 783 cm-1 provids us an useful measure for the degree of transformation, whereas in some cases results of the X-ray diffraction where not unequivocal. The transformation starts between 185 und 216°C, depending on the temperature of the substrate during the preparation of the films. Films deposited onto substrates below -35°C proved to be amorphous. They can be crystallized at temperatures below the α-β-transformation point.
    Notes: Die thermische Umlagerung von α-CuPe-Aufdampfschichten in die β-Form wird IR-spektroskopisch, röntgenographisch und elektronenmikroskopisch verfolgt. Quantitative Aussagen über den Umwandlungsgrad folgen mit befriedigender Genauigkeit aus der (normierten) Extinktion der IR-Bande bei 783 cm-1, während die Röntgenstreukurven bei Aufdampfschichten z.T. keine befriedigenden Ergebnisse liefern. Der Beginn der Umwandlung wurde bei Temperaturen zwischen 185 und 216°C beobachtet und hängt von der Substrattemperatur bei der Herstellung der Schicht ab. Schichten, die auf Substrate von Temperaturen unter -35°C sublimiert wurden, erwiesen sich als röntgenamorph. Sie kristallisieren beim Tempern unterhalb der α-β-Umwandlungstemperatur.
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  • 59
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mono- and binuclear carbonyls of 5th, 6th and 8th group transition metals react with organosulfonyl chlorides, RSO2Cl, to form organosulfinato metal chlorides with, in the case of electronegative R (R = CF3), metal(II) and, in the case of electropositive (R = p-CH3C6H4), metal(II) or (III). Bis(organosulfinato) complexes are obtainable from metal(II) chlorides and sodium organosulfinates.In all these new sulfinato compounds the ligand is bound to the metal through both its oxygen atoms; this is deduced from the IR spectra.
    Notes: Durch Umsetzung von ein- oder zweikernigen Metallcarbonylen der 5.,6. und 8. Nebengruppe mit Organosulfonylchloriden, RSO2Cl, erhält man bei elektronegativem R (R = CF3) durchwegs Organo-doppel-O-sulfinato-metallchloride mit zweiwertigem Metall. Bei elektropositiveren organischen Resten (R = p·CH3C6H4) entstehen in Abhängigkeit von der Oxydierbarkeit des betreffenden Metallcarbonyls ebenfalls Organo-doppel-O-sulfinato-metallchloride mit zwei- oder dreiwertigem Metall.Bis(organosulfinato)-Komplexe, in denen die Liganden gleichfalls über beide O-Atome an das Metall geknüpft sind, werden prinzipiell durch Reaktion von Metall(II)-chloriden mit Natriumorganosulfinaten dargestellt.Die O-Sulfinato-Verknüpfung aller hier neu beschriebenen Verbindungen geht aus den IR-Spektren hervor.
    Additional Material: 6 Tab.
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  • 60
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 373 (1970), S. 168-175 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The compounds LaSF, CeSF, EuSF and LaSeF were prepared by reaction of the sesquichalcogenides with the fluorides. The sulphidefluorides crystallize with the PbFCl structure, while LaSeF crystallizes with an unknown orthorhombic structure.
    Notes: Durch Umsetzung der Chalkogenide mit den entsprechenden Fluoriden wurden die Verbindungen LaSF, CeSF, EuSF, und LaSeF erhalten. Die Sulfidfluoride kristallisieren im PbFCl-Typ, LaSeF orthorhombisch in einer bisher nicht bekannten Struktur.
    Additional Material: 4 Tab.
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  • 61
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 373 (1970), S. 182-188 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: By the reduction of C3F7Fe(CO)4J with sodium borohydride in methanol a solution is obtained from which derivatives of the very unstable perfluoropropyliron tetracarbonyl hydride C3F7Fe(CO)4H can be precipitated. The compounds [C3F7Fe(CO)4]2Hg and [C3F7Fe(CO)4]2[Fe(N2C12H8)3] have been characterized by their IR, NMR and mass spectra.
    Notes: Durch Reduktion einer Lösung von Heptafluor-n-propyl-eisen-tetracarbonyljodid, C3F7Fe(CO)4J, in Methanol mittels Natriumboranats entsteht eine Lösung, aus der Quecksilbercyanid und Tri-o-phenanthrolin-eisen(II)-sulfat Derivate des Heptafluor-n-propyl-eisentetracarbonylwasserstoffs, [C3F7Fe(CO)4]2Hg und [C3F7Fe(CO)(4)]2[Fe(N2C12H8)3] ausfällen. Aus dem Phenanthrolinderivat kann mittels Phosphorsäure das äußerst zersetzliche Carbonylhydrid C3F7Fe(CO)4H in Freiheit gesetzt werden. Die beiden beständigen Verbindungen sind durch IR-, NMR- und Massenspektren charakterisiert worden.
    Additional Material: 3 Tab.
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  • 62
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 373 (1970), S. 198-203 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: LiHC2O4 · H2O crystallizes in space group P 1 with a0 = 4.99, b0 = 6.16, c0 = 3.45 Å; α0 = 96.3°, β0 = 98.0°, γ0 = 80.4° and Z = 1. The crystal structure has been determined by direct methods. Refinement by least squares methods resulted to R1 = 8,3%. In the structure the oxalate group is not planar. The angle between the two O—C—O planes is 2.9°.
    Notes: LiHC2O4 · H2O kristallisiert in der Raumgruppe P 1 mit a0 = 4,99, b0 = 6,16, c0 = 3,45 Å; α0 = 96,3°, β0 = 98,0°, γ0 = 80,4° und Z = 1. Die Kristallstruktur wurde mit direkten Methoden bestimmt. Die Verfeinerung der Parameter nach der Methode der kleinsten Quadrate ergab einen R1-Wert von 8,3%. Die Oxalatgruppe ist in der Struktur nicht eben. Der Winkel zwischen den beiden O—C—O-Ebenen beträgt 2,9°.
    Additional Material: 1 Ill.
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