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Biomedical subjects

R Gossrau

Publications and source records attributed to R Gossrau.

At least 73 records · Page 4Linked to original sources
PubMed1990

Light microscopical detection of D-amino acid oxidase activity in unfixed cryostat sections of rat kidney and liver using the cerium-DAB-cobalt-H2O2 procedure and a semipermeable membrane.

The two-step method for the light microscopical detection of oxidase activity using cerium ions and a visualization procedure with diaminobenzidine and nickel or cobalt ions as introduced by Anger-müller and Fahimi, has been improved. Inactivation by fixation and leakage of D-amino acid oxidase molecules were avoided by the application of unfixed cryostat sections adhered to a semipermeable membrane separating the sections from a gelled incubation medium. Optimum activity in rat kidney and liver was obtained by increasing the cerium concentration from 3 to 30 mM and the Tris-maleate concentration from 100 to 200 mM in the incubation medium for the first step. D-proline was used as substrate and a concentration of 20 mM gave maximum activity. The second visualization step was performed in a medium consisting of DAB, cobalt and hydrogen peroxide. Final reaction product was found in a granular form in the basal part of the epithelial cells of the proximal tubules and in liver parenchymal cells. The activity in periportal areas was much higher than in pericentral areas. Cytophotometric analysis revealed that a 30 times higher activity could be detected when using the membrane technique in comparison with incubations in aqueous media. The specificity of the reaction was proven by a nearly complete inhibition of the reaction by beta-hydroxybutyrate.

Animals↗
PubMed1990

Enhancement of immunoreactivity of von Willebrand factor in vascular endothelial cells of rat organs after glucocorticoid administration.

Our study showed that synthetic glucocorticoids are potent mediators of vWF-reactivity in rat fetal placental, liver and lung vascular elements. However, it is not yet possible to draw final conclusions from these results obtained only by immunohistochemical studies using antibody against vWF, since the mechanisms in factor VIII/vWF are highly complex. Further investigations for example with anti-vW AgII and measurements of blood vWF levels after treatment with synthetic glucocorticoids may deliver more insight into the mechanisms of action of these drugs. Investigations after treatment of pregnant rats with methylprednisolone might help, in addition, to find out whether the increased vWF-reactivity in caused by special substituents in the steran ring of the glucocorticoids.

Animals↗
PubMed1990

Indoxyl alfa-D-galactoside as the temporarily last substrate for glycosidase histochemistry. The present state of the art in histochemical glycosidase research using indoxyl glycosidas.

Initiated by the recently published histochemical method for the investigation of alfa-D-galactosidas with an indoxyl substrate, the current state of this group of synthetic compounds in light and electron microscopic histochemical glycosidase research is evaluated whereby historical, functional, methodological and applied aspects are considered. Beginning with the introduction of indoxyl acetate for non-specific esterase in 1951 and 1952 numerous other indoxyl substrates and mostly substituted in the 5- and 4-position of the indol ring by Br and Cl were developed to study histochemically non-specific phosphatases and glycosidases and frequently used in indigogenic, azoidoxyl, tetrazolium salts and metal salt techniques for catalytic (activity) histochemical and less often for immunohistochemical, affinity histochemical and hybridohistochemical purposes. The last substrate which became available and was validated for activity histochemistry was 5-Br-4-Cl-3-indoxyl alfa-1-galactoside for alfa-1-galactosidase. At present, the indoxyl glycosides are more widely used than 5-Br-4-Cl-3-indoxyl acetates and phosphates when compared with the alternative synthetic (artificial) naphthol, 6-Br-2-naphthol or ternative synthetic (artificial) naphthol, 6-Br-2-naphthol AS substrates, and among the indoxyl glycosides those for the oxoglycosidases lactase, maltase-glucoamylase, glucoamylase, acid beta-D-galactosidase, neuroaminidase and alfa-D-galactosidase are superior to other artificial compounds. When one considers in addition, electron microscopic catalytic glicosidase histochemistry (ultracytochemistry, 5-Br-4-Cl-3-indoxyl is the only suitable moiety for this purpose. These glycosidase can mostly be localized in plasma membranes or lysosomes and also measured there in tissue sections but are also found in secretion granules, endoplasmic reticulum and organ lumina.

Animals↗
PubMed1990

Enzyme histochemical and histological changes in the adult rat kidney after prenatal gentamicin exposure.

Treatment of rats between day 15 and 20 of gestation with gentamicin caused histological as well as enzyme histochemical lesions in the kidney of the one year old offspring (F1 generation). Other organs were not significantly affected. Primarily in the female kidney dilated convoluted proximal tubulus with reduced or absent staining for brush border and lysosomal proteases, phosphatases and glycosidases and mitochondrial dehydrogenases were observed. In comparison, glomeruli were less frequently damaged and contained fewer capillary loops or irregularly arranged tissue elements with lowered or no activities for plasma membrane-associated proteases as well as specific and non-specific phosphatases. In addition, the activities of proteases and phosphatases in cortical and medullary endothelial cells of capillaries were reduced or even abolished in the kidney of the female and male F1 generation after treatment of their mothers with gentamicin.

Animals↗
PubMed1989

Localization of a putative cell adhesion molecule (gp110) in Wistar and Fischer rat tissues.

A plasma membrane glycoprotein (gp110) involved in cellular adhesion was studied in Wistar and Fischer rats. For quantitative analysis of the gp110 molecule a sandwich-ELISA was used. High quantities of gp110 were found especially in the liver, small intestine, submandibular gland and lung. The distribution and localization of the gp110 were investigated by immunohistochemistry utilizing soluble complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase antibodies. Immunoreactivity was present in plasma membranes of vascular endothelial cells of some organs. Furthermore, immunostaining also occurred in plasma membranes of lymphocytes, exocrine gland cells, excretory duct cells, hepatocytes, epithelial cells of the small intestine, kidney and vesicular gland and in the cytoplasm of renal connecting and collecting duct cells. The localization of gp110 in the luminal domain of the plasma membrane at many sites suggests that this glycoprotein is also involved in processes distinct from cell adhesion.

Animals↗
PubMed1989

Placental toxicity in rats after administration of synthetic glucocorticoids. A morphological, histochemical and immunohistochemical investigation.

Administration of the synthetic glucocorticoids dexamethasone and triamcinolone to pregnant rats between gestational day (GD) 16 and 20 caused dose-dependent placental lesions on GD 21 and 22 which were detected by morphological, histochemical and immunohistochemical means. Maternal blood spaces, trophoblast layer and fetal blood vessels were altered primarily in the centre of the placental labyrinth. Less severe changes were found in the junctional zone, chorionic plate and intraplacental yolk sac. On GD 21, low doses increased the amount of glycogen, while high doses induced a loss of glycogen. gamma-glutamyl transpeptidase activity was increased in the spongiotrophoblast and the labyrinthic trophoblast and dipeptidyl peptidase IV activity in fetal capillary endothelium, whereas alpha-glutamyl aminopeptidase and microsomal alanyl amino-peptidase were not affected. Additionally, in the fetal capillary endothelium an increase of immunoreactivity for the von Willebrand factor occurred. These data suggest that synthetic glucocorticoids affect placental tissues at different and rather specific levels, which may in turn disturb placental function and contribute to fetal maldevelopment.

Animals↗
PubMed1989

Analysis of hepatotoxicity in maternal and fetal rats after glucocorticoid administration by lipid histochemistry and thin layer chromatography.

Changes in lipid metabolism of fetal and maternal rat livers were investigated on day 20 of pregnancy after administration of either 3 mg/kg or 24 mg/kg triamcinolone-acetonide or 124 mg/kg hydrocortisone in crystalline suspension to the mothers on day 15 of pregnancy. Sudan black B and Nile red as well as the UV-Schiff reaction and thin layer chromatography were used to study qualitatively the response of lipids to these glucocorticoids. Generally, after application of triamcinolone-acetonide fetal livers accumulated more lipids as toxic response to this glucocorticoid than the maternal organ; the degree of lipid accumulation was clearly dose-dependent in the fetuses. After hydrocortisone treatment, lipids in maternal livers were slightly, those in the fetuses were not affected. Histochemistry and thin layer chromatography revealed an accumulation of neutral lipids, especially of triglycerides and fatty acids which both contained increased amounts of ethylene bonds after treatment with triamcinolone-acetonide. The results also show that using combined histochemistry and thin layer chromatography, the analysis of hepatic lipids is a promising tool for the assessment of toxic effects of glucocorticoids on fetal and maternal hepatocytes in rats.

Animals↗
PubMed1989

Enhancement of gentamicin-induced nephrotoxicity by Mg deficiency in non-pregnant rats. Morphological, enzyme histochemical and immunohistochemical studies.

Non-pregnant rats fed an Mg-deficient diet showed some degenerated and calcified proximal tubules in the inner region of the medullary rays accompanied by reduced or absent enzyme activities. After gentamicin treatment some damaged convoluted proximal tubules occurred. Enzyme histochemistry revealed decreased activities for brush border and lysosomal hydrolases; using immunohistochemistry lesions were detectable for the cytoskeletal proteins keratin and vimentin. Administration of gentamicin to Mg-deficient rats led to a further decrease of hydrolase activities in obviously intact proximal tubules and drastic structural and enzymatic defects as well as alterations of the cytoskeletal proteins in the convoluted and straight segments of other proximal tubules and to a lesser degree also in glomeruli and further portions of the tubular apparatus including the collecting ducts.

Animals↗
PubMed1989

Enhanced light microscopic visualization of oxidase activity with the cerium capture method.

Visualization methods for the light microscopic detection of the activity of oxidases after being localized with cerium ions as reported by Angermüller and Fahimi (1988a, b) are not suitable for the demonstration of H2O2-genrating oxidases at sites with low activity. Therefore, the cerium-diaminobenzidine (DAB) visualization procedure of these authors was modified. Nickel or cobalt ions were added to the DAB solution together with small amounts of H2O2. Visualization was performed in a one-step-method. This modified visualization technique enables light microscopic detection of amino acid oxidase activity in kidney and liver cells where it was found with the original method but the amounts of final reaction product were considerably higher. Moreover, the DAB-nickel-H2O2 and DAB-cobalt-H2O2 procedures were more sensitive than the cerium-lead method of Angermüller and Fahimi (1988a, b). The method appeared to be specific, because final reaction product was not found after control incubation. Especially the DAB-nickel-H2O2 procedure can also be used for immunohistochemistry when glucose oxidase serves as the enzyme label.

3,3'-Diaminobenzidine↗
PubMed1989

Biochemical properties of dipeptidyl peptidase IV in liver and hepatoma plasma membranes.

In the present investigation we compared the glycoprotein DPP IV from rat liver and Morris hepatoma 7777 by means of biochemical and immunological methods. For that purpose nine monoclonal anti-DPP IV-antibodies recognizing four different epitopes and a monospecific anti-DPP IV-antiserum were applied. In the homogenates of both tissues a plasma membrane-bound and a soluble form were detected. The immunological cross-reactivity of both forms was demonstrated with the antiserum and the monoclonal antibodies against the epitopes A, B and C while epitope D was restricted to liver plasma membrane. Differences of the distinct DPP IV forms were exhibited in the molecular weights, isoelectric points and peptide maps. In the hepatoma homogenate only 10% of DPP IV activity was found compared to normal liver but the ratio of soluble to membrane-bound form is higher in the hepatoma than in the liver. The fractionation of the homogenates into different cell components revealed for the liver a continuous increase of DPP IV activity from the endoplasmic reticulum fractions to the Golgi apparatus and finally to the plasma membranes. By contrast, in hepatoma the flow from the Golgi apparatus to plasma membrane was greatly reduced. The loss of DPP IV from the surface of cultured hepatoma cells was concomitant with a decrease of cell-substratum adhesion. DPP IV was found to be inserted into the liver plasma membrane by two different mechanisms, a phospholipase C-sensitive and a papain-sensitive one. In the hepatoma the phospholipase C-sensitive anchorage was not expressed. Besides liver and hepatoma the distribution of DPP IV was characterized in various rat organs by enzyme activity, histochemistry and immunohistochemistry with the anti-DPP IV-antibodies.

Animals↗
PubMed1989

Kinetic and end-point microdensitometry (section biochemistry) of gamma-glutamyl transpeptidase and dipeptidyl peptidase IV in the mature mouse decidua and visceral yolk sac.

gamma-Glutamyl transpeptidase (EC 2.3.2.2) and dipeptidyl peptidase IV (EC 3.4.14.5) were measured in mature mouse decidual and visceral yolk sac epithelial cells by means of kinetic (continuous) and end-point (static) microdensitometry (section biochemistry). For continuous measurements a new device for starting the enzyme reaction allowed the first readings to be made already during its very early phase. Since the initial reaction rates of both peptidases were very different in the plasma membrane of decidual and also in the visceral yolk sac epithelial cells, it was difficult to select a sufficient number of cells of the same activity for representative measurements on the basis of kinetic microdensitometry. Static section biochemistry was performed also for statistical reasons, i.e., in order to obtain information about the distribution of the activities of the decidual and visceral epithelial cells and the number of measurements required to guarantee valid data. Various groups of decidual and visceral yolk sac epithelial cells with different gamma-glutamyl transpeptidase and dipeptidyl peptidase IV activities were formed. In this way, different activities of gamma-glutamyl transpeptidase were measured in the plasma membrane of the cells of the antimesometrial, intermediate, and mesometrial decidua. Compared with dipeptidyl peptidase IV, gamma-glutamyl transpeptidase was significantly more active in the plasma membrane of the antimesometrial decidual cells and microvillous zone of the visceral yolk sac epithelial cells.

Animals↗
PubMed1989

Lesions and repair of cells of maternal mice after valproic acid (VPA) treatment on day 8 of pregnancy: an enzyme histochemical analysis.

Mice received a single teratogenic dose of the antiepileptic drug valproic acid (VPA; 500 mg/kg i.p.) on 8th d of pregnancy. The effects of VPA were studied primarily by enzyme histochemical means over a period of 48 h. Plasma membrane-associated hydrolases were more affected than lysosome-associated ones. Lesions were not found in the spleen, but a slight response, without morphological damages, was observed in the lung and thymus. Comparatively more severe injuries, which were not accompanied by clear-cut structural changes either, occurred in the liver. The most severe damages including morphological lesions were noticed especially in the proximal tubules of the kidney. The first damages were already seen after 3 h and concerned primarily the liver. After 12 h, a maximal response to VPA was detected in all organs. Repair of most of the enzymatic lesions set in after 24 h. After 48 h, lesions were not longer seen in the lung and thymus. In contrast, enzymatically and morphologically injured proximal renal tubules could still be found after this period as a response to a single dose of VPA; in the liver only enzymatic lesions were present at this stage.

Alkaline Phosphatase↗
PubMed1989

Histochemical detection of alpha-D-galactosidase with 5-Br-4-Cl-3-indoxyl alpha-D-galactoside.

5-Br-4-Cl-3-indoxyl alpha-D-galactoside was used as a new substrate in azoindoxyl, indigogenic, and tetrazolium procedures for the detection of alpha-D-galactosidase in the light microscope. Compared with the simultaneous azo-dye methods using 1-naphthyl or 6-Br-2-naphthyl alpha-D-galactoside as substrates and hexazotized pararosaniline for simultaneous coupling, primarily the azoindoxyl method with hexazotized pararosaniline and the indigogenic technique proved to be superior. The azoindoxyl reaction is recommended for the localization of alpha-D-galactosidase in lysosomes when freeze-dried celloidin-coated cryostat sections are used: the indigogenic procedure should be employed for the detection of the total activity of the enzyme in combination with the technique of semipermeable membranes. The tetrazolium reaction delivered high amounts of formazan as the final reaction product; however, its localization was less precise than with the azoindoxyl and indigogenic methods. Conspicious species differences were found; except for the small intestine of suckling mice the highest activities of alpha-D-galactosidase were present in different immature and mature rat organs when compared with mouse, hamster, guinea-pig, marmoset monkey, and human tissues.

Aging↗
PubMed1989

[Ultrastructure of the gastrointestinal epithelium in the marmoset (Callithrix jacchus)].

The epithelium of the stomach and intestine of one and three days old as well as adult marmosets was investigated using transmission electron microscopy and was compared with already existing data of man and the laboratory rodents, rat, mouse and guinea-pig. On postnatal day (PD) 1, the enterocytes possessed an inframicrovillous membrane system and giant lysosomes which were absent in adult marmosets whereas the surface and glandular epithelial cells of the stomach showed all structures which were also typical for adult animals. Enterocytes rich in fat and glycogen were only present on PD 1. In the large intestine the vacuolated cells were more frequently seen on PD 1 and 3 than in adult marmosets. The endocrine cells of newborn animals corresponded to those in the gastric and intestinal epithelium of mature animals, occurred everywhere in the lower digestive tract and could be subdivided at least into EC, ECL, D and L and EG cells respectively; a further subdivision was not possible by conventional transmission electron microscopy. Compared with rats, mice and guinea-pigs mostly used for developmental studies of the digestive tract, marmoset monkeys differed especially from the gastrointestinal epithelium of rats and mice but also from guinea-pigs. By contrast comparisons with the human situation are difficult due to the lack of representative electron microscopic findings on the gastrointestinal epithelium. If one considers the close phylogenic relationship between marmosets and man, the marmoset data should be transferable to the human situation rather than the findings obtained for rats, mice and guinea-pigs. In the epithelium of the adult gastrointestinal tract clear-out ultrastructural differences could not be found between these species.

Animals↗
PubMed1988

Characterization of different forms of dipeptidyl peptidase IV from rat liver and hepatoma by monoclonal antibodies.

Nine monoclonal antibodies directed against DPP IV from rat liver plasma membranes were obtained. They recognized four different epitopes (A, B, C and D) of the enzyme. The epitopes A, B and C were located on the outside of the hepatocyte plasma membrane and were shared by DPP IV from hepatoma plasma membrane and the soluble form. Epitope D appeared to be partly inserted in the membrane and was found exclusively in the liver. Epitopes A, B and C and DPP IV revealed by histochemical means showed similar distribution patterns on frozen sections of various rat tissues, while epitope D did not show such a correlation. DPP IV is inserted in liver plasma membrane by two different mechanisms, one being phospholipase C-sensitive, while in hepatoma the enzyme is anchored in this membrane by a phospholipase C-resistant mechanism only.

Animals↗