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Biomedical subjects

E Morgenstern

Publications and source records attributed to E Morgenstern.

At least 73 records · Page 4Linked to original sources
PubMed1980

Three-dimensional reconstruction of human blood platelets using serial sections.

The typical reconstruction model of an unstimulated human platelet is presented. It shows a strict spatial order of organelles and enodmembrane systems. The surface-connected vesicle system is predominantly found in the periphery. The dense tubules constitute a continuous, interconnected system found just under the surface of the platelet. They are particularly pronounced in the vicinity of the marginal microtubules. All organelles are in contact with the dense tubular system (DTS). Granules, vesicles and plasmalemma fuse into the tubules. The platelet organelles are centrally located. Lysosomal granules are primarily shperical and all of them contain a nucleoid. This speaks in favor of a single type of storage organelle in the platelet. The dense bodies and their remnants (large, solitary vesicles) are not joined by the other endomembrane systems, as in the case of the granules. A particular pathways for the release of substances from these organelles is now morphologically plausible. Mitochondria are small, solitary granules surrounded by dense tubules. Owing to its unique position with the platelet, the DTS's role as a mediating and regulatory structure is discussed.

Blood Platelets↗
PubMed1979

The nucleated thrombocytoid cells. I. Electron microscopic studies on chicken blood cells.

By analyses of electron micrographs it was investigated whether nucleated thrombocytes of chickens described in the literature can be differentiated from lymphoid cells with sufficient certainty as an independent cell system. The result was negative. The mixture of lymphoid cells and so-called thrombocytes investigated was extremely polymorphous and, unlike mammalian platelets, proved to be one cell system containing younger and more mature cells. In the literature cells with signs of overmaturity or activation are designated as thrombocytes. Our studies suggest that a genuine thrombocyte system of chickens and other birds is not existent. The cell hitherto considered as nucleated thrombocytes seem to belong to the lymphoid system.

Animals↗
PubMed1979

Disassembly of microtubules in the Lesch-Nyhan Syndrome? (Lesch-Nyhan syndrome and microtubules).

The Lesch-Nyhan syndrome is an unusual disease. It combines neurological disorders, behavioural disturbances, metabolic changes and haematological symptoms. The syndrome is caused by an X-chromosomal transmitted enzyme deficiency of the 'salvage pathway' in purine metabolism. The hitherto unexplained pathogenesis was the reason for investigations into metabolism and morphology of the blood cells of a patient suffering from the syndrome. Along with the defect in guanine nucleotide resynthesis there was a defect of microtubules in platelets and a sphaerocytosis in red cells, which could be the result of a disassembly of structural proteins. The development and maintenance of the highly heteromorphic structure of nerve cells and the neuronal function including axonal transport of cell organelles and transmitters is dependent on microtubules. Thus a disassembly of microtubules could be the mechanism in the pathogenesis of this complex syndrome.

Adenine Phosphoribosyltransferase↗
PubMed1977

[Cytochemical studies of ultrathin frozen sections of blood platelets].

Results obtained by conventional techniques and freeze-ultramicrotomie have been compared. Ultrathin frozen sections of platelets, which are fixed by glutaraldehyde, freeze-protected by polyvinyl-pyrrolidone and encapsulated in gelatin show a well preserved fine structure after staining with buffered OsO4, phosphotungstic, phosphomolybdic or ammoniummolybdic acid. The preservation of polysaccharides or mucopolysaccharides depends on a suitable fixation, that of glycogen in certain cases depends on a double fixation (glutaraldehyde and OsO4). Cytoplasmic nucleoproteins like ribosomes are visible only after drying of sections and staining with uranyl-acetate. Lipids, both membrane lipoproteins as well as lipids in the matrices of cell organelles, are well preserved. For example the zinc-iodide osmiumtetroxide reaction yields positive results in frozen sections contrary to such obtained by conventional methods. Furthermore, the extraction of altered lipids after staining with dyes like acridine orange does not take place with this method. For this reasons the freeze-ultramicrotomy seems to be an useful alternative method.

Animals↗
PubMed1976

[Lesch-Nyhan syndrome without self-mutilation: biochemical and morphological studies on blood cells (author's transl)].

Absent enzyme activity of hypoxanthine-guanine-phosphoribosyl transferase in erythrocytes was demonstrated in the blood from a 21-year-old man with spastic tetraplegia, choreoathetosis, oligophrenia, and hyperruricaemia which developed after birth. But there was no tendency towards self-mutilation, considered to be characteristic of the full-blown picture of the disease. This case thus runs counter to the view that the enzyme defect is the cause of the inevitable, stereotyped change in behaviour. Unusual morphological changes of all blood-cell systems confirm the dependence of nucleic acid synthesis on the "salvage pathway" of the purine nucleotides, which is abnormal in this inherited disease.

Adult↗
PubMed1975

Morphology of gastrointestinal effects of aspirin.

The effect of acetylsalicylic acid (aspirin) on the ultrastructure of gastric and jejunal mucosa was investigated in patients undergoing gastric surgery and in guinea pigs. The drug caused various degrees of damage to the surface mucous cells in both species perceptible as general signs of cytolysis in situ or as desquanmation. In patients pretreated with aspirin, an increase of secondary lysosomes was noted in the gastric parietal cells but not in the animals. In the intestinal epithelial cells of both species there was a marked increase of multivesicular bodies and the occurrence of transitional stages between the two organoids suggest a functional interrelationship. Since no specific alteration of any cellular organoid was detected, the drug-induced injury is assumed to occur on a molecular level in the cytoplasm. It is concluded that the intracellular concentrations of aspirin in gastrointestinal mucosal cells mechanims but that high drug concentrations may lead to irreversible cell damage.

Animals↗