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Biomedical subjects

R Gossrau

Publications and source records attributed to R Gossrau.

At least 127 records · Page 7Linked to original sources
PubMed1983

Demonstration of protease isoenzymes by two-dimensional polyacrylamide electrophoresis.

A two-dimensional polyacrylamide electrophoresis system is described for the detection of protease isoenzymes using 4-methoxy-2-naphthylamine derivates as substrates. With this technique is possible to detect isoenzymes differing in molecular weight by separation according to size and shape. This is not possible by the use of isoelectric focusing alone.

Animals↗
PubMed1983

Fluorescence histochemical detection of hydrolases in tissue sections and culture cells.

Fluorescence and dye histochemical methods are compared for the investigation of hydrolases in sections and culture cells. At present, only some of the synthetic substrates with fluorescent leaving groups may be used for the fluorescence localization of these enzymes in sections. This limitation is due to a reduced fluorescence intensity and/or diffusion of the fluorescent tags. Satisfactory results are obtained for alkaline phosphatase, non-specific esterases and proteases with naphthol AS and 4-methoxy-2-naphthylamine coupled to nitrosalicylaldehyde. If, however, cultured monolayer cells are investigated, all synthetic substrates with fluorescent tags are suitable, including those that have so far only been used for biochemical hydrolase measurements. The fluorescent leaving groups are naphthol AS and its derivates, 4-methoxy-2-naphthylamine, aminomethylcoumarin, aminomethyltrifluoromethylcoumarin, methylumbelliferon, fluorescein and, with some limitations, also 1- and 2-naphthol. These fluorescence methods are more sensitive than the corresponding dye procedures. In addition, the fluorescence techniques allow the use of more synthetic substrates and therefore more information become available than with dye histochemistry about the enzymic properties of culture cells.

Animals↗
PubMed1983

Peptide and protein handling by proteases in the kidney of laboratory rodents.

Nephrons, collecting ducts and blood vessels contain a variety of proteases. They are localized in surface membranes or/and lysosomes either at the same or at different sites and show that not only the different segments of the nephron with its different cells but also their subcellular structures take part in the degradation, activation and modification of peptide and propeptide hormones with different mechanisms. Furthermore, the single cell types and segments of the nephron are specialized as far as the degradation of peptide hormones and the protein degradation in general (Christensen and Maunsbach 1980, Maunsbach et al. 1980, Lit.) are concerned.

Animals↗
PubMed1981

Investigation of proteinases in the digestive tract using 4-methoxy-2-naphthylamine (MNA) substrates.

Aminopeptidase (AP) A, B, and M, gamma-glutamyltranspeptidase (GGT), endopeptidase I and II, membrane-associated endopeptidase I and II, dipeptidylaminopeptidase (DAP) I, II, and IV, trypsin and chymotrypsin were investigated with 4-methoxy-2-naphthylamine (MNA) substrates and ester proteinases with n-acetyl-L-methionine-1-naphthylester as substrate in the digestive tract of laboratory rodents. Biochemically, proteinases and ester proteinases show different activities in the salivary glands, esophagus, stomach, liver, pancreas, duodenum jejunum, ileum, and colon; sex differences in proteinase and ester proteinase activity were measured, especially in the submandibular gland of rats and mice. Histochemically these enzymes are preferentially localized in surface membranes, lysosomes, secretion granules, and Golgi apparatus of cells of the endocrine and exocrine secretory system, resorptive system and immune system of the digestive tract. Besides the general occurrence of lysosomal (DAP I and II, single cell types and functional units of these systems possess their own individual proteinase and ester proteinase equipment. The cells of the granulated tubules of rat and mouse submandibular gland contain endopeptidase I and ester proteinases, its acinar cells DAP IV, the chief cells of the stomach APA, enteroendocrine cells APA, APM, and DAP II, hepatocytes DAP IV or GGT and DAP IV, lymphocytes GGT and DAP IV, and enterocytes trypsin, chymotrypsin, and membrane-associated endopeptidase I and II. Sex differences in proteinase activity are most conspicuous in the granulated tubule cells of the rat and mouse submandibular gland. The data suggest that proteinases and ester proteinases are involved in specific functions of the cells of the digestive tract. Furthermore, myoepithelial cells, smooth muscle cells of the muscular layer of the stomach and intestine, connective tissue cells (including mast cells) and fibers, nerve cells of the myenteric plexus and the capillary bed of the digestive organs are equipped with some of these proteinases and with ester proteinases and show organ differences.

2-Naphthylamine↗
PubMed1981

[Morphology and zonal division of the ductus epididymidis of rats. I. Investigation of semithin-sections (author's transl)].

The ductus epididymidis of adult rats can be subdivided in 9 zones. All zones consist of principal cells (pc), basal cells and granular and agranular leucocytes. However, dependent on the zone the length of the microvilli, basophilia of the Golgi region and the size and number of vacuoles and granules of the pc show differences. In addition, apical and bottle-shaped (narrow cells) occur in zone 1 and 2 and basal clear cells in zone 2-4. Furthermore, 4 types of clear cells (cc) can be distinguished which differ in number, size and staining properties of their granules; cc with light granules (type I) exist in zone 5 and cc with dark granules (type II) predominate in zone 6 whereas cc with a mixed granule type (type III) occur especially in zone 7 and cc with grey granules (type IV) are limited to zone 8 and 9. Beside the different structure and distribution of the epithelial cells the diameter of the duct lumen and the height of the epithelium differ in the course of the ductus epididymidis.

Animals↗
PubMed1981

[Morphology and zonal division of the Ductus epididymidis of rats. II. Electron microscopic investigations (author's transl)].

The light microscopical zonal division of the ductus epididymidis of adult rats is substantiated and extended by ultrastructural differences of the epithelial cells lining the duct. The principal cells are rich in endocytotic vesicles and possess a well-developed Golgi apparatus in all 9 zones of the duct. Polymorphous lysosomes, however, preferentially occur in the principal cells of zone 4-7; the principal cells of zone 1-3 and 8-9 contain other types and less numerous lysosomes. The rough endoplasmic reticulum (ER) and possible exocytotic vesicles and vacuoles predominate in the principal cells of zone 1-3 and the smooth ER in those of zone 7. The clear cells are always poor in microvilli and contain different amounts of vacuoles, vesicles, lipid and lipoid droplets and lysosomes. Light droplets and lysosomes are typical for the clear cells of zone 5, dark droplets for those of zone 6; the clear cells of zone 7 possess many dark droplets and lysosomes; and in zone 8 and 9 these cells contain numerous vesicles, vacuoles and lysosomes. The apical cells belong to the group of principal cells; in addition, bottle shaped-cells (narrow cells), basal clear cells and 2 populations of intraepithelial leucocytes exist; the leucocytes leave the blood capillaries, penetrate the epithelium and enter the lumen of the duct. If, in addition, enzyme histochemical and experimental data are respected the principal and clear cells are involved in zonal specific absorptive processes but perhaps also in secretion processes into the lumen of the duct, the clear cells of zone 5 and 6 may be responsible for the secretion of hydrolases present in the sperm plasm. Clear signs for endocrine secretion are not seen; at least some of the leucocytes may represent immunocompetent lymphocytes which seem to be not identical with those in the epithelia of other organic systems.

Animals↗
PubMed1980

Study on dipeptidylpeptidase II (DPP II).

The activity of dipeptidylpeptidase II (DPP II; E.C. 3.4.14.2) was investigated by biochemical and histochemical methods in rat, mouse and guinea-pig organs as well as in human enterobiopsies. Lys-Pro-MNA and Ala-Pro-MNA showed the most favorable kinetic properties (Km, Vmax) and proved to be the most sensitive substrates for biochemical and histochemical studies of DPP II. Lys-Ala-MNA is more specific and is to be preferred due to its relatively low hydrolysis by DPP IV. Lys-Ala-2NA is suitable for the biochemical determination of DPP II activity. Lys-Ala-1NA, Leu-Ala-2NA, Phe-Pro-2NA and Phe-Pro-MNA are inferior. The pH optimum of DPP II amounts to 5.5. Cacodylate, phosphate, citric acid phosphate and succinate buffers deliver similar hydrolysis rates; with citrate and acetate buffers the recorded activities are lower. The reaction can be inhibited by 1 mM DFP, 50 mM Tris and 10 mM puromycin. In the ileum of suckling rats and in human enterobiopsies similar data (Km, pH optimum, optimal substrate concentration) were obtained by biochemical determination and by quantitative histochemistry (microdensitometry) with Lys-Ala-MNA. For the histochemical demonstration of DPP II freeze-dried celloidin-coated cryostat sections are very suitable. Frozen sections of formaldehyde and glutaraldehyde fixed tissue blocks are inferior due to a higher inhibition of DPP II and less precise localization of the azo-dye. Km values and optimal pH are identical in fresh and fixed material. Fast Blue B is the best coupling agent for light microscopical localization. DPP II is present in all organs and tissues investigated. Conspicuous organ and species differences exist. In adult rats the highest DPP II activity resides in the kidney, epididymis and spleen; in guinea-pigs the epididymis and testis are the most active organs. In the majority of guinea-pig organs the DPP II activity is lower than in rats. The histochemical demonstration of DPP II shows, in addition, cell-dependent differences of DPP II activity. In most cells the enzyme activity is depicted in lysosomes. Highly active are lysosomes of cells of proximal renal tubules, macrophages, thyroid cells, clear and principal cells of the epididymis of adult animals and of enterocytes of suckling rats. Lysosomes of endocrine cells of adenohypophysis, pancreas, stomach, small intestine and nerve cells display moderate activity. In lysosomes of smooth muscle cells (intestine, myometrium), myocardial cells, and fibers of striated muscle the enzyme is also present. Spermatids and sperms of guinea-pigs are highly active. In some cases secretion granules of endocrine and exocrine gland cells display a positive reaction. Possibly the Golgi apparatus and the endoplasmic reticulum also show a positive staining in the principle cells of the rat and mouse epididymis. Furthermore, DPP II seems to be secreted into the lumen of several organs.

Animals↗