Zum Aufbau der Epiphysenfuge im chronischen Vitamin-A-Mangel — eine histologische und morphometrische Studie an der proximalen Tibiaepiphyse

1994

Vitamin A und analoge Substanzen (Retinoide) uben auf Wachstum und Differenzierung des Bewegungsapparates einen wesentlichen Einflus aus. In zahlreichen in vitro-Untersuchungen konnte gezeigt werden, das der Metabolismus von Chondrozyten und Osteoklasten durch toxische Vitamin A-Konzentrationen in komplexer Weise beeinflust wird [1]. Hingegen ist der physiologische Wirkungsmechanismus von Retinol bei der Wachstumsregulation des Knochens noch weitgehend unklar. Das Ziel der vorliegenden in vivo-Untersuchung war deshalb die morphologische Analyse der Epiphysenfuge an Ratten, wobei Tiere im chronischen Vitamin A-Mangel mit Kontrollen verglichen wurden.

?-Carotene Supplements Cannot Meet All Vitamin A Requirements of Vitamin A-Deficient Rats

1993

Crystalloid lysozyme inclusions in Paneth cells of vitamin A-deficient rats.

1990

The effect of vitamin A-deficiency on jejunal Paneth cells in rats was investigated. Crystalloid particles were observed in secretion granules of Paneth cells from 6 out of 8 rats with vitamin A-deficiency. The particles were similar to those found in Paneth cells under other experimental conditions. Using an immuno-electron-microscopic technique we demonstrated a clear lysozyme immunoreactivity of these particles. In 2 vitamin A-deficient rats tubular structures have been detected in addition to the crystalloid particles. Crystalloid particles or tubular structures were not detectable in a control group of 8 vitamin A-supplemented rats. The morphological alterations of Paneth cells may be …

Crystalloid Lysozyme Inclusions in Paneth Cells of Vitamin A-Deficient Rats

1992

The effect of vitamin A-deficiency on jejunal Paneth cells in rats was investigated. Crystalloid particles were observed in secretion granules of Paneth cells from 6 out of 8 rats with vitamin A-deficiency. The particles were similar to those found in Paneth cells under other experimental conditions. Using an immuno-electron-microscopic technique we demonstrated a clear lysozyme immunoreactivity of these particles. In 2 vitamin A-deficient rats tubular structures have been detected in addition to the crystalloid particles. Crystalloid particles or tubular structures were not detectable in a control group of 8 vitamin A-supplemented rats. The morphological alterations of Paneth cells may be …

Uptake and Metabolism of ?-Carotene Isomers in Rats

1993

Long-Term Administration of High Dose Vitamin A to Rats Does Not Cause Fetal Malformations: Macroscopic, Skeletal and Physicochemical Finds

1996

A rat model was used to investigate whether high oral doses of vitamin A lead to fetal malformations and to what extent retinyl esters (RES) are transferred from the mother to the fetuses. Retinol and RES concentrations in plasma behave similarly in rats and humans. When high concentrations of vitamin A are administered, plasma retinol concentrations remain relatively constant, whereas plasma RES increased in parallel with the dose. To achieve an elevation from approximately 150 to > 1525 nmol x L(-1) in the experimental group before mating, female Ibm: RORO (spf) rats were fed a maintenance diet enriched with 15.2 x 10(3) retinol equivalents (RE) x kg(-1) at the start and increased stepwis…

Aufnahme und Verteilung von14C-Retinylacetat in Organe und Sinnesgewebe (Innenohr) des Meerschweinchens

1985

Es wird uber die Aufnahme und chemische Identifizierung von14C-Retinylacetat in das Innenohr des Meerschweinchens nach per oraler Verabreichung berichtet. Die Untersuchung wurde aus methodischen Grunden bei Vitamin-A-mangelernahrten Tieren durchgefuhrt. Es findet sich eine zeitabhangige Verteilung in den Sinnesgeweben, die der anderer Organe gleicht. Die chemische Identifizierung zeigt, das das als Retinylacetat verabreichte markierte Vitamin A in den membranosen Strukturen des Innenohres in Form des Retinylpalmitats zu finden ist. Dies mag ein Hinweis sein auf die Fahigkeit des Innenohrgewebes, die Transportform des Vitamins A, das Retinol, zu verestern und eventuell auch zu speichern.

Distribution patterns in glycoconjugate expression during the development of the rat palate.

1994

The distribution of complex carbohydrate structures during the embryonic development of the rat palate was analysed by examining lectin-binding patterns in serial paraffin and cryostat sections. With few exceptions, the binding patterns showed a general increase in lectin receptors in the more developed stages of palatogenesis. High mannose oligosaccharides were especially amplified during development. Terminal fucose molecules were not expressed. In contrast, terminal sialic acid molecules were ubiquitously distributed in epithelial and mesenchymal tissues. Non-sialylated terminal N-acetylglucosamine was specifically restricted to evolving bone matrix. Before palatal fusion, quantitative b…

Vitamin A deficiency increases noise susceptibility in guinea pigs.

1990

The effect of vitamin A deficiency in guinea pigs on noise-induced temporary threshold shift (TTS) was evaluated after short (15 min) acoustic overstimulation with a moderate (90 dB) broad-band white noise. Some guinea pigs were fed ad libitum a purified diet deficient in vitamin A (VAD group) until biochemical signs of deficiency occurred. A second, control group (VA group) received the same diet as well as 100 IU vitamin A daily by pharyngeal tube. Cochlear potentials were recorded by special computerized equipment using implanted electrodes. Before acoustic stimulation, a baseline value was determined with a test stimulus [90 dBA (A-filter according to usual DIN instructions)] correspond…

Characterization of glycoconjugate expression during development of Meckel's cartilage in the rat

1995

The staining patterns of 24 biotinylated lectins were analyzed in serial sections of the mandible of 13- to 21-day-old rat embryos by means of the avidin-biotin-peroxidase method. A ubiquitous distribution of binding sites was demonstrated after incubation with Con A (Canavalia ensiformis), DSL (Datura stramonium; except bone matrix), and WGA (Triticum vulgare). ECL (Erythrina cristagalli), GSL I (Griffonia simplicifolia), SJA (Saphora japonica), VVL (Vicia villosa), DBA (Dolichus biflorus), UEA I (Ulex europeus), and LTA (Lotus tetragonobolus) were constantly negative. In early stages of development, GSL II (Griffonia simplicifolia II) was a selective marker of prechondral blastema. In con…

Sensitive Analysis of Retinyl Esters by Isocratic Adsorption Chromatography

1989

A sensitive method for the determination of retinyl esters, including their geometric isomers, by isocratic adsorption HPLC is described. The development of a special recycling system allows the separation of all-trans-, 13-cis, 11-cis- and 9-cis-retinyl palmitate, -stearate, -oleate, -palmitoleate and -linoleate with short retention times and high sensitivity. Extraction of the retinyl esters from various organs with mobile phase avoids additional evaporation steps. The method was evaluated by the determination of retinyl esters in small tissue samples such as tongue, trachea and inner ear. This is the first report of the detection of retinyl esters in these tissues, which are known to dep…