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Biomedical subjects

H Bartel

Publications and source records attributed to H Bartel.

At least 55 records · Page 3Linked to original sources
PubMed1978

Morphology of nuclear ribonucleoproteins in the early period of liver regeneration.

A cytochemical study on the nuclei of hepatocytes in the regenerating liver after partial hepatectomy by the method of Higgins and Anderson was carried out. The behaviour of the ribonucleoprotein components of the nucleus, using EDTA according to Bernhard, revealed altered proportions of the fibrillar and granular components of the nucleoli in the early phase of regeneration and morphologic changes in nuclear RNP, especially in perichromatin fibrils. At 6 h after hepatectomy, the reaction with perichromatin fibrils (FP) was intense, localized around fields of condensed chromatin, which suggests intense transcription of extranucleolar RNA. The behaviour of the remaining nuclear ribonucleoproteins was uncharacteristic.

Animals↗
PubMed1978

The brush border of rabbit kidney, a cellular compartment free of glycolytic enzymes.

Activities of four enzymes of the glycolytic pathway, hexokinase, glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase and lactate dehydrogenase, were determined in a vesicular brush-border preparation from rabbit kidneys. The specific activities of the enzymes were decreased several-hundredfold in the brush-border preparation compared with a kidney homogenate, but the enzymes were not totally absent. Density-gradient centrifugation of the brush-border preparation yielded brush border of even higher purity and also a characteristic pattern of distribution for each of the contaminating intracellular membranes. The presence of hexokinase in the brush-border preparation could be traced to contaminating mitochondria, and that of glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase and lactate dehydrogenase to contaminating vesicles derived from the endoplasmic reticulum. The brush-border vesicles contained some ATP. An intravesicular concentration of 0.1mm was estimated, indicating that the vesicles had retained at least a part of their original content. Experiments in which fluorescein isothiocyanate-dextran (mol.wt. 20000) was present during cell lysis revealed that much, but not all, of the brush-border contents had been exchanged with the medium. The complete absence of glycolytic enzymes from brush-border vesicles, which had retained part of their original content, indicates that the brush border does not contain glycolytic enzymes in vivo and can be thought of as a compartment of its own, somehow separated from the cytoplasm.

Adenosine Triphosphate↗
PubMed1978

Histochemical and ultrastructural changes in locally gamma-irradiated rabbit intestine.

The effect of local irradiation of a 50-cm long intestinal segment outside the abdominal cavity in rabbits has been studied. The rabbits were killed at 12, 24, 48 and 72 hours after irradiation. Activities of succinate and lactate dehydrogenase, acid and alkaline phosphatase and thiamine pyrophosphatase were studied histochemically in the irradiated intestinal segment and in the part of the intestine remaining in the abdominal cavity. The same material was studied electron-microscopically. Changes in enterocytes of the intestinal crypts were observed mainly in the mitochondria and in the form of a chaotic distribution of endoplasmic membranes and densely scattered ribosomes. In intestinal crypt cells, irradiation was followed by a depression in the activities of succinate and lactate dehydrogenases and alkaline phosphatase. These changes were related to postradiation damage, not to recovery.

Acid Phosphatase↗
PubMed1977

Electron microscopic study of peripheral giant-cell reparative granuloma.

Six giant-cell tumors have been examined by electron microscopic methods in order to determine their histogenesis and to expand knowledge of cell structures. The examination of giant cells revealed an abundance of cell organelles, especially mitochondria. Apart from typical stromal cells, such as fibroblasts, macrophages, and mast cells, clusters of stromal "light" cells were often found with an intimate relation between their cell membranes. The role and function of these cells is not well known. Between fibroblasts of regular appearance with a small number of cytoplasmic organelles, others were found with an incrased number of mitochondria. These cells often formed aggregates. This suggests that giant cells develop through the association of stroma fibroblast cells.

Cell Nucleus↗
PubMed1976

Ultrastructural changes in the myocardium due to acute uremic syndrome.

The acute uremic syndrome caused by bilateral ligation of the ureters leads to ultrastructural changes in the myocardium after 12 hours. They are characterized by dilatation of the tubules of the endoplasmic reticulum and by the focal disintegration of mitochondria. After 24 hours, besides damaged mitochondria the glycogen granules were reduced and the number of pinocytic vesicles in endothelial cells increased. After 48 hours advanced changes of mitochondria associated with myelin structure and dense bodies could be observed. The myofibrils were fragmented. Sometimes contraction rings occurred. After 72 hours all myocardial structures were strongly damaged, especially in the subendocardial and subepicardial regions. In this period the hyperhydration of the myocardium led to dissociation of the myofibrillar structures.

Animals↗
PubMed1976

Ultrastructure of the chorionic villus of the human placenta of the second and third trimester pregnancy.

38 human placentae of the 14th week of normal gestation were studied ultrastructurally. The thickness of the syncytial layer of villi varied markedly, and the syncytial cytoplasm showed marked vacuolization, which increased in the course of pregnancy in association with intensification of processes of resorption and absorption and hormonal function of the syncytium. Toward the end of the 2nd and at the beginning of the 3rd trimester of pregnancy, hypertrophic cytotrophoblastic cells appeared, whose ultrastructural character indicated functional stimulation. This observation contradicts the widely held view that cytotrophoblastic cells undergo gradual reduction in the course of pregnancy.

Chorionic Villi↗
PubMed1976

Radiation-induced histochemical and ultrastructural changes in the enterocytes in the rabbit.

Ultrastructural changes and enzyme activities in the cell organelles of rabbits were studied within 1, 3, 6, 9, 15 and 30 days of the irradiation with 550 rads of gamma-radiation. Between the 1st and 3rd day after irradiation there was a fall in the succinate dehydrogenase activity in the swollen and frequently tigroidal mitochondria whose number distinctly diminished. By the 15th day these changes disappeared. In the hyaloplasm there was weakening of the reaction for lactate dehydrogenase after 1 day, and an increase in number of polysomes, glycogen granules and smooth vesicles after 3-9 days after irradiation. The glucose-6-phosphatase activity was unchanged and so was the shape of the Golgi apparatus. The activity of lysosomal enzymes and the number of lysosomes in the experimental groups was approximately normal. By the 6th day the activity of alkaline phosphatase in the striated border was lowered, subsequently normal. On the whole, the intensity of postradiation changes in the intestinal mucosal epithelium is correlated with the rhythm of proliferation and shedding of epithelial cells, although some signs of injury persist for longer time periods.

Animals↗
PubMed1976

Histoenzymatic and ultrastructural changes in the hepatocytes of gamma-irradiated rabbits.

Ultrastructural changes and intracellular enzyme activities in the hepatocytes were studied in rabbits irradiated with 550 rads of gamma rays at 1,3,6,9,15 and 30 days after irradiation. Swelling and marked rarefaction of the mitochondrial matrix observed on the first day were followed by gradual condensation of the matrix between the 6th and 9th day. This state was accompanied by marked reduction in the succinate dehydrogenase activity, ehich gradually returned to the normal by the 30th day of observation. In the hyaloplasm, the most intense changes developed between the third and sixth day and were manifested by clearing of the cytoplasm and marked fragmentation of the endoplasmic membranes, with concurrent negligible decline of the lactate dehydrogenase activity and unchanged glucose-6-phosphatase activity. In the Golgi apparatus, vacuolization of the cytoplasm and fragmentation of smooth membranes were most pronounced on the 6th day and were correlated with a weakened and diffuse reaction for thiamine pyrophosphatase. The alkaline phosphatase activity was irregularly distributed in the lobule. The activities of lysosomal hydrolases, i.e. acid phosphatase, beta-glucuronidase and non-specific esterase, had various localizations within the lobules. The strongest deviations from the normal and of longest duration. (up to 9 days) were seen in the Browicz-Kupffer cells. Complex studies on the same material conducted concurrently with the use of different methods showed that radiation damages structure and function in unequal degrees. Moreover, within the same organ the cellular response to ionizing radiation varies according to the character, localization and functional state of the cells. Deviations from the normal state occur between the first and ninth days, most of the structural and functional elements showing sings of return to the normal about the 15th day after irradiation.

Acid Phosphatase↗