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Biomedical subjects

D Sasse

Publications and source records attributed to D Sasse.

At least 55 records · Page 3Linked to original sources
PubMed1979

The development of functional heterogeneity in the liver parenchyma of the golden hamster.

Prenatal and postnatal stages of the development of golden hamsters were studied histochemically and biochemically. It was shown that, beginning with the 12th gestational day, the fetal liver starts to store glycogen, and that this process reaches its maximum a birth. Glycogen phosphorylase and glucose-6-phosphatase (G6Pase)-activity increased drastically in the last two days before birth, glycogen phosphorylase preceding G6Pase. As a histochemical characteristic, an even distribution of glycogen, glycogen phosphorylase and G6Pase activity is found in the liver parenchyma at birth. During the first two postnatal weeks typical heterogeneous patterns of distribution developed: glycogen depletion could be demonstrated predominantly in zone 1 of the liver acinus, this being at the same time the area of highest glycogen phosphorylase and G6Pase-activity. The periportal zone 1 thus became characterized as the primary site of glycogenolysis (glycogen phosphorylase) and gluco(neo)genesis (G6Pase). "Metabolic Zonation" is interpreted as the chemomorphological equivalent of the regulatory function of the liver as a glucostat.

Animals↗
PubMed1979

Histochemical studies on carbohydrate metabolism in rat liver after galactosamine administration.

The development of hepatitis, induced in 48 rats by the administration of galactosamine (GalN) in varying doses, was studied with the use of substrate and enzyme histochemical techniques. The so-called atypical glycogen, which is at first highly resistant to diastase, was shown to be digestible after deamination. The increasing accumulation of atypical glycogen during the course of GalN-hepatitis conceals the loss of normal glycogen when the PAS-reaction is used. Nevertheless glycogenolysis could also be demonstrated by the increasing activity of phosphorylase. The acid phosphatase activity was progressively diminished, which was interpreted as signifying early lysosomal damage. G6Pase activity remained nearly constant but SDH showed a decrease in activity after 12 h. These histochemical results are considered to provide deeper insight into the pathological mechanism of GalN-hepatitis.

Acid Phosphatase↗
PubMed1979

Identification of G6PDH-active sinusoidal cells as Kupffer cells in the rat liver.

The aim of this study was to identify the G6PDH-active sinusoidal cells in the rat liver described by Rieder et al. (1978). Because of their number and distribution in the liver parenchyma, endothelial cells and pit cells could be excluded. Fat-storing cells were specifically marked by vital staining with vitamin A and identified by fluorescence microscopy. Kupffer cells could be detected after vital staining with carmine. Both staining methods allowed a subsequent incubation for the demonstration of G6PDH activity in the same unfixed cryostat section. Whereas more than 80% of the fluorescent particles were found outside the enzyme-positive cells, all G6PDH-active cells contained carmine particles. After counting the G6PDH-active cells, an estimation of 0.217 x 10(8) cells/g liver tissue was obtained. The results indicate that high G6PDH activity is common to all Kupffer cells, and is therefore a highly specific marker enzyme for this class of sinusoidal liver cells.

Animals↗
PubMed1978

NADP-dependent dehydrogenases in rat liver parenchyma. I. Methodological studies on the qualitative histochemistry of G6PDH, 6PGDH, malic enzyme and ICDH.

At present soluble NADP-dependent dehydrogenases are histochemically demonstrated in three different ways: according to the standard method incubation in aqueous media leads to the precipitation of formazan, the formation of which depends entirely on the presence of endogeneous NADPH2-tetrazolium reductases. With the two more recently established methods these reductases are by-passed with the use of intermediate electron acceptors incorporated in the medium. In addition, enzyme diffusion is inhibited either by an increased viscosity of the medium (PVA) or by a semipermeable membrane separating the medium from the section. Depending on the technique applied different distribution patterns have been described. By altering the concentrations of substrates, coenzyme, tetrazolium salt and cytochrome oxidase inhibitor, it was possible to improve both the PVA and membrane methods. Although similar results were obtained, because of its advantages the PVA method is recommended in this report and a detailed description is given. Using the latter for the demonstration of glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), malic enzyme (ME) and isocitrate dehydrogenase (ICDH), characteristic distribution patterns were obtained in the liver parenchyma of male and female rats. For the first time a high G6PDH activity could be demonstrated in nonparenchymal cells which are mainly found in zone 1 of the liver acinus.

Animals↗
PubMed1978

Increase of the gluconeogenic and decrease of the glycolytic capacity of rat liver with a change of the metabolic zonation after partial hepatectomy.

During the first 72 h after 67% partial hepatectomy of female Wistar rats (160 g) the specific activities [mumol X min-1 X (g liver)-1] of the glucogenic glucose-6-phosphatase and fructose-bisphosphatase and of the glycolytic hexokinase and 6-phosphofructokinase remained essentially constant. However, the activity of the glycolytic pyruvate kinase (L- plus M2-type) was decreased slightly and that of glucokinase was decreased markedly to below 30%, while the glucogenic phosphoenolpyruvate carboxykinase was increased to over 200%. Between 10 and 40 h after partial hepatectomy, when the proliferation started in the periportal area, a shift of the glucogenic glucose-6-phosphatase-rich zone from its normal periportal to an intermediate or even perivenous position was observed histochemically. After 48 h, when the proliferation was no longer restricted to the periportal zone, the normal glucose-6-phosphatase zonation (as before partial hepatectomy) was restored. Glycogen was degraded rapidly during the first 4 h after operation; it was later repeatedly resynthesized and degraded in correlation with the feeding rhythm of the animals. The zonation of glycogen metabolism was in accord with the observed zonation of glucose-6-phosphatase.

Animals↗
PubMed1977

[Histochemistry of the carbohydrate metabolism in cysts of Toxoplasma gondii (author's transl)].

Mice were infected with cysts of the ALT strain Toxoplasma by intraperitoneal injection. After 2-8 weeks disseminated cysts could be demonstrated in the brain tissue. All cysts showed identical histochemical characteristics, independent of their sizes or their cell number. The encysted organisms were intensely stained after the PAS-reaction. This polysaccharide is highly diastase and acid resistant. Glycogen synthetase activity could not be demonstrated, but phosphorylase activity was very high. The energy metabolism was characterized by a high lactate dehydrogenase activity, whereas the reaction for succinate dehydrogenase activity only leads to sparse deposits of reaction products. The carbohydrate content is interpreted to be not only a store of energy substrate but also a store of biosynthetic substrate. It is assumed that a part of the liberated glucose at high activities of G-6-P-DH and 6-P-G-DH is metabolized by the hexose monophosphate shunt, the pentoses of which may contribute to nucleic acid synthesis which is necessary for the proliferation of the encysted organisms.

Animals↗
PubMed1977

[The fructose induces "glycogenosis". III. Histochemical and morphometrical studies of glycogen metabolism in mouse liver after fructose overload (author's transl)].

INTRODUCTION: After feeding fructose for 7 days rat liver cells show an accumulation of glycogen, a high activity of glucose-6-phosphatase combined with a SER- and RER-reduction. This result was reviewed by mouse liver cells using histochemical and morphometrical methods. MATERIAL AND METHODS: 60% fructose in drinking water was given mice as only nutritional source. Controls had free access to Altromin-R-standard diet and drinking water. Glycogen and glycogen metabolizing enzymes are demonstrated in the course of an 1-14 days fructose diet. After a 7 days diet liver tissue was analysed morphometrically. RESULTS AND DISCUSSION: Feeding of fructose leads to a high glycogen content, combined with a high activity of glycogen-phosphorylase and glucose-6-phosphatase in the liver parenchyma of mouse. Glycogen-synthetase activity falls to a low level. The SER and RER and the peroxisomes are reduced. The single volume of the hepatic nucleus is decreased and the hepatocellular chondrioma is transformed in a smaller number of larger mitochondria. Compared with the rate the analysed organelles and enzymes of mouse liver show only slight quantitative differences. The increase of glucose-6-phosphatase and simultaneous reduction of endoplasmic reticulum-membranes is illustrated by the dynamic structure of endoplasmic reticulum-membranes, which adapt to metabolic changes. The variable turnover of different parts of endoplasmic reticulum-membranes seems to be very important.

Animals↗
PubMed1976

Electron microscopic evidence for a muscle layer in the wall of the terminal hepatic venule in the rat.

Electron microscopically smooth muscle cells could be detected in the walls of the terminal hepatic venules of the rat liver. These muscle cells are double layered in the following venous channels, the intercalated veins. It is supposed that these smooth muscle cells play an important role as outlet sphincters of the liver sinusoids. Furthermore, fenestrations could be found in the endothelial lining of terminal hepatic venules.

Animals↗