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T H Schiebler

Publications and source records attributed to T H Schiebler.

At least 19 recordsLinked to original sources
PubMed1990

Quantitative distribution of AChE-positive neurons in the hippocampus of young and aged rats.

Acetylcholinesterase (AChE)-positive neurons were counted in the different layers of the rostral (septal) third, the middle third and the caudal (temporal) third of the hippocampus from 3 month (young) and 27 month old rats (aged) using AChE stained cryostat sections. The rats were treated with 3 and 2.5 mg of diisopropylphosphofluoridate/kg body weight, respectively 3 h before sacrifice. The study showed -1) a high numerical density of AChE-positive neurons (10.9 to 18.9 perikarya/mm2) in the hilus (fascia dentata), the str. oriens/pyramidale of CA1 and the subiculum, a particularly low density (less than 0.1 perikarya/mm2) in the str. granulosum and moleculare of the dentate area; -2) a significant (p less than 0.05) linear increase of the numerical density in most of the hippocampal layers from the rostral to the caudal pole; -3) no significant differences between young and aged animals; - and 4) a higher sensitivity to DFP-treatment in aged than in young animals. The distribution of AChE-positive neurons corresponds with the distribution of somatostatin-immunoreactive neurons described in the literature. A modulatory effect on neurotransmission is discussed as a possible function of the AChE in peptidergic neurons.

Acetylcholinesterase↗
PubMed1988

Cytochrome oxidase histochemistry in the rat hippocampus. A quantitative methodological study.

The diaminobenzidine (DAB) method was adapted for the microphotometric determination of cytochrome c oxidase (cyt ox) in the rat hippocampus. The qualitative and quantitative investigations at the light microscopic level showed that acetone and cytochrome c pretreatment of cryostat sections resulted in a significant increase of demonstrable cyt ox activities. The final incubation medium consisted of 7.5 mM DAB, 2% polyvinylalcohol (PVA) and 6% dimethyl sulfoxide in 0.1 M Hepes buffer; final pH 7.5. PVA was used to keep DAB and artificially oxidized DAB in solution. In the kinetic and endpoint measurements a linear response of the reaction with highest slope was observed only in the initial 5-6 min of reaction. Thereafter the slope decreased. Ultracytochemical demonstrations, which were performed as a topochemical control, showed reaction product only in mitochondria (cristae and intermembranous space). In contrast to vibratome sections all mitochondria reacted positively in cryostat sections of aldehyde-fixed hippocampi. The enhancement of reaction after acetone pretreatment of cryostat sections (light microscopic level) and after a freezing step in ultracytochemistry is discussed in connection with diffusion problems of DAB through mitochondrial membranes.

3,3'-Diaminobenzidine↗
PubMed1986

Sex-related differences in the handling of fluorescent ovalbumin by the proximal tubule of the rat kidney.

Sex-dependent protein handling in the rat renal tubular system was studied both qualitatively and quantitatively using the method of direct fluorescent protein tracing. The protein tracer, fluorescent ovalbumin, was synthesized by conjugating hen ovalbumin with fluorescein isothiocyanate (FITC), and the fluorescence characteristics of fluoresceinthiocarbamyl (FTC)-ovalbumin conjugates with different degrees of labelling were studied. Heavily labelled tracer was intravenously injected into male and female rats, and both kidneys were perfused; the right kidney was then homogenized and used for quantitative fluorometric measurements, while the left kidney was perfusion fixed and prepared for fluorescence microscopy. The tubular reabsorption of fluorescent ovalbumin was studied 4 min and 10 min after the injection of different doses (1.4, 7.0 and 14.0 mg/kg body weight) of the tracer, and the tubular catabolism was investigated in animals killed 60 and 120 min after the injection. Fluorescence microscopy demonstrated that, in both sexes and regardless of the dose administered and the time after injection, specifically fluorescent protein or its degradation products was only present in the epithelial cells of the proximal tubule. With regard to sex-dependent differences in protein handling, fluorometry indicated that at 4 min (7.0 mg) and at 10 min (all doses) after injection, female animals had reabsorbed more fluorescent protein than males. With regard to the catabolic phase, both the fluorescence microscopy and the fluorometric results showed that the female rats had degraded the fluorescent tracer at a significantly higher rate than males. The results are discussed in connection with sex-dependent proteinuria in rats.

Animals↗
PubMed1984

Quantitative histochemistry of the angiotensinase A (APA) in the renal glomeruli of rats after stimulation of the renin-angiotensin system.

Quantitative histochemical measurements of aminopeptidase A (APA, angiotensinase A) were done kinetically in the kidney glomeruli of rats after short-term experiments (treatment with furosemide as well as captopril for 2, 4, and 6 h). The APA activities increased after treatment with furosemide or captopril. Highest activities were determined after 4 h using furosemide and 6 h using captopril. It is concluded that glomerular APA activities correspond to the renin/angiotensin plasma levels and that the fast changes of APA activities are well demonstrable by kinetic densitometric measurements in situ.

Aminopeptidases↗
PubMed1984

[Sex differentiated protein pattern in the urine of the rat following castration].

Protein excretion and protein fractions according to their molecular weight (SDS polyacrylamide-gelectrophoresis) were studied in the urine of male and female rats before and after castration. The polyacrylamide-gels were investigated qualitatively as well as quantitatively by densitometry. Male rats excrete considerably more protein in the urine than female rats. The values for the absolute protein quantity in 24-h-urine and the relative proteinuria (mg protein per 24 h and 100 g body weight) are five and three times higher, respectively, in males than in females. After castration proteinuria decreases significantly in both sexes, in males, however, more considerably (by about 75%) than in females (by about 30%), so that there is no significant difference in relative proteinuria between castrated males and females. The electrophoresis method used in this study allows to distinguish at least 10 to 11 protein fractions in the total urinary protein of both sexes within a molecular weight range from about 94.000 d to 14.000 d. Low molecular weight proteins (about 31.000 d to about 14.000 d) represent in both sexes the main part of the urinary protein. Females, however, excrete relatively more high molecular weight proteins (about 94.000 d to 60.000 d; about 25% of total urinary protein) than males (about 15% of total urinary protein). Concerning the relative parts in total urinary protein there are sex differences in all protein fractions, especially, however, in the fraction with a molecular weight of about 19.000 d (males more than 50%, females about 17% of total urinary protein). Castration causes in males more distinct changes in the relative parts of protein fractions in total urinary protein (drastic decrease of the 19.000-d-fraction) than in females. The results can be interpreted among other things in connection with a sex different handling of proteins in the proximal tubule of the rat kidney. The lysosomal catabolism of proteins in the proximal tubule is probably lower in males than in females, thus contributing to a higher proteinuria and a higher excretion especially of low molecular weight proteins in males in comparison with females.

Animals↗
PubMed1983

Development of the capillary system in the neurohypophysis of the rat.

The development of the vascular system in the neurohypophysis of the rat shows three periods of structural differentiation. The first period lasts until the 17th fetal day. During this period the superficial and the border plexuses are formed, and rapid vascularization of the neural lobe anlage takes place. The end of this period is marked by the formation of the perivascular space. The second period lasts from the 18th fetal day until the 10th day after birth. Its initial phase is characterized by the appearance of the first endothelial pores. During this period the formation of the internal capillaries proceeds, together with the maturation of the previously formed vascular elements. The third period lasts from the 10th postnatal day until the end of the first month after birth. At the end of this period the vascular net of the neural lobe has attained its fully developed state. The results of this study, together with data from previous investigations, lead to the conclusion that at the 18th fetal day the neural lobe displays signs of functional activity, and that the maturation of the vascular network in the neural lobe occurs more rapidly than the maturation of its other structural components.

Animals↗
PubMed1981

[Endothelial cells in the blood vessels of mature human placental villi].

In the microcirculatory system of mature human placental villi (small arteries, arterioles and venules respectively, pre- and postcapillaries, capillaries, and postcapillary venules) two endothelial cell types do exist. Numerous micropinocytotic vesicles are common to both types. In addition type I cells are distinguished by bundles of filaments which are probably contractile. Type II cells, however, are marked by a highly developed rough endoplasmatic reticulum, Golgi apparatus, and secretory vesicles. In all vascular parts examined type I cells predominate. The number of endothelial cells with secretory granules decreases in the direction of the venous vascular bed.

Arterioles↗
PubMed1980

Prenatal and early postnatal development of the glial cells in the median eminence of the rat.

The development of the glial cells of the rat median eminence (ME), including the supraependymal cells, was investigated from embryonic day (ED) 14 through postnatal day (PD) 7, and pituicyte development from ED 12 through ED 17. The anlage of the ME and neurohypophysis shows a neuroepithelial-like structure at ED 12. From ED 13 to 15, the cells of both regions start to differentiate. At the ultrastructural level, only one cell type appears. At the beginning of ED 16, glioblasts of the oligodendrocyte and astrocyte series migrate laterally (from the region of the arcuate nucleus) into the ME. Also at this time the first distinctive structural features appear in the neurohypophysial anlage, the cells of which later develop into pituicytes. Starting at ED 18, tanycytes and astrocytic tanycytes arise in the ME from local glial cells, and somewhat later oligodendroblasts and astroblasts are formed from immigrant glioblasts. Due to their common features, the pituicytes, tanycytes and astrocytic tanycytes apparently represent different forms of the same parent cell type. Microglial and supraependymal cells are first seen at ED 12. Initially, they resemble the prenatal phagocytic connective tissue cells and mature in fetus into typical electron-dense microglia and macrophage-like supraependymal cells. Both cell types are apparently of mesodermal origin. The microglial elements of the ME probably migrate from the mesenchyma through the basement into the nervous tissue. The intraventricular macrophages of the infundibular region may originate from microglia, epiplexal cells and subarachnoid macrophages.

Aging↗
PubMed1980

Histochemical, autoradiographic and electron microscopic investigations of the renal proximal tubule of male and female rats after castration.

After castration of 90-day-old male and female rats, changes appear in the renal proximal tubule. A distinction can be made between early changes (up to 10th postoperative day) and later changes (20th-30th postoperative day). Between the 3rd and 5th day after castration the kidney of the females shows an increase in free estrogen receptors (biochemical studies) which are localized in the pars contorta of the proximal tubule (autoradiographic studies), while the male kidney shows a marked increase in urinary protein excretion up to the 10th day after castration. Proximal tubule changes detectable histochemically and electron microscopically do not appear until day 20 or 30 after castration. The results of castration are similar in segments S1 and S2. By days 20 and 30 after castration there is a decrease in the activity of lysosomal enzymes (acid phosphatase, acid beta-galactosidase). Electron microscopy shows a conspicuous decrease in the number of giant lysosomes (mainly in females) and apical vacuoles (mainly in males). A marked increase in the number of lysosomes is found in the S3 segment; females always have more lysosomes than males. The number of peroxisomes is also greatly increased; they appear circular in the females but can assume bizarre shapes in the males. Lipid droplets appear in the basal region of the tubule cell of segments S2 and S3 in the males. The sex differences are preserved in all segments even after castration and become even more pronounced in the S3 segment.

Animals↗
PubMed1980

Steroid hormone binding receptors in the rat kidney.

The studies were done on 93 Wistar rats of both sexes. Binding capacity and affinity for 3H-estradiol were determined biochemically in the cytosol fraction of renal homogenates. Free cytoplasmic estrogen binding sites were demonstrated in a portion of the females (Kd 5.2-17.8 x 10(-10) mol/l): in 33.3% of normal animals, in 54.6% 3-4 days after ovariectomy, and in 25% 17-18 days after ovariectomy. The investigation of females which received estradiol or testosterone replacement after castration, as well as of uncastrated or castrated males, led to negative results. Thaw-mounted autoradiography was used to study the retention of radioactivity from 3H-estradiol or 3H-testosterone in normal and castrated animals and in animals which received corresponding hormone replacement after castration. In all animals, specific silver granules were found in the cytoplasm and nucleus of proximal tubules cells from the S1 and S2 segments of juxtamedullary nephrons, particularly in the females. Only a few silver granules were observed in the S segments; some cells in males were marked by a heavy nuclear accumulation of silver granules following the injection of 3H-testosterone. In the distal tubules, only isolated silver granules were found in some cells. Somewhat more radioactivity was found in the cytoplasm of the cells of the collecting ducts in the inner medullary zone.

Animals↗
PubMed1979

[Postnatal development of the median eminence in the rat].

The postnatal development of the zonation and the glial cells of the median eminence (EM) was investigated in male rats. On the 1st day of life, the ME is mostly undifferentiated. In contrast to adult animals, only the ependymal, subependymal and palisade layer can be observed. The remaining area is almost unorganized. A more distinct zonation of the EM exists about the 10th day of life. Ependymal and subependymal layer are reduced to a monolayer of cells; in addition, the reticular layer appears. The adult structure of the EM is seen for the first time about the 14th day of life. The development of the zonation of the EM is finished at the 3rd week of life. Mature microglial cells occur in the median eminence at the 1st day of live. Ependymal cells, tanycytes and astrocytic tanycytes (Zaborszky and Schiebler 1978), which can be found in a greatter amount as an individual cell type, are relatively immature. Protoplasmatic astrocytes occur at the 4th, and fibrous astrocytes at the 14th day of life. The development of glial cells may be finished at the end of the 4th week of life together with the maturation of oligodendrocytes. The opening of the 3rd ventricle needs 2 weeks, that of the recessus infundibularis is finished after the 3rd week of live. On the basis of their lipid granules and the synaptic contacts with neurosecretory axons it is presumed that the tanycytic and astrocytic tanycytes have regulatory functions in connection with neurosecretory processes.

Aging↗
PubMed1978

The effect of sex hormones on the proximal tubules in the rat kidney.

The three segments (S1, S2, S3) of the proximal tubule of the rat kidney were investigated, with special reference to lysosomes, after castration, estradiol application, and at the end of pregnancy. Especially in S1 and S2 castration induces an increase of cellular autophagy. The nuclei become smaller; endoplasmic reticulum (ER), ribosomes, and Golgi apparatus are reduced; catabolism predominates. In S1 more giant lysosomes occur; the total number of lysosomes increases whereas acid phosphatase activity decreases at the same time. Sex differences which exist in untreated animals disappear. Substitution with estradiol causes an activation of the proximal tubule cells: Heterophagy predominates, and cellular autophagy is reduced. Nuclear size is unchanged; ER, ribosomes and Golgi apparatus show a clear increase. Giant lysosomes are absent in S1. On the whole lysosomes are larger, but less numerous than after castration. Acid phosphatase is highly active. All changes are most evident in S3. At the end of pregnancy the proximal tubule cells are "stressed" considerably: Pinocytotic activity increases, and large numbers of cell organelles and many lipid vacuoles can be observed. The basal lamina in S1 and S2 becomes thicker. Lysosomes enlarge and increase in number in all segments; giant lysosomes are absent in S1; acid phosphatase is extremely high. The results indicate that sex hormones directly influence the regulation of the proximal tubule cell; moreover, they are indirectly important for the functioning of the kidney via changes in the whole organism.

Animals↗
PubMed1978

[Uptake of peroxidase by activated nerve cells of the hypothalamus (author's transl)].

After thirst or adrenalectomy followed by dehydration electron microscopy reveals an activation and an increased uptake of peroxidase in the nerve cells of the supraoptic, paraventricular, ventromedial and praemamillar nuclei. The amount of peroxidase which is taken up runs parallel with the activation of the corresponding nerve cells. After rehydratation the activity of the nerve cells and the uptake of peroxidase decrease. The incorporation of the enzyme by the nerve cells differs depending on the region investigated: After thirst peroxidase is taken up especially by the nerve cells of the supraoptic and paraventricular nuclei. After adrenalectomy, however, this is true for the ventromedial and praemamillar nucleus. In the magnocellular nuclei peroxidase is preferentially incorporated by the perikarya, whereas in the parvocellular nuclei the uptake of the enzyme predominates in the dendrites. Within the nerve cells peroxidase is only seen in heterophagic bodies. The ependyma above the paraventricular nucleus takes up peroxidase in low amounts via the cell membrane which borders the III. ventricle; high amounts are incorporated by the lateral and basal plasmalemma.

Animals↗