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Biomedical subjects

B Vogt

Publications and source records attributed to B Vogt.

At least 127 records · Page 7Linked to original sources
PubMed1985

Alteration in the capacities as well as in the zonal and cellular distributions of pyruvate kinase L and M2 in regenerating rat liver.

Pyruvate kinase L (PKL), the glucoregulatory isoenzyme of adult parenchymal cells, and M2 (PKM2), the isoenzyme of proliferating and non-parenchymal cells, were measured, using a specific anti-PKL antibody for differentiation, in total liver homogenates, in isolated parenchymal and non-parenchymal cells as well as in microdissected periportal and perivenous liver tissue from regenerating rat liver after two-thirds partial hepatectomy. Moreover, the zonal distribution of PKL was studied using immunohistochemical techniques. In total liver homogenates PKL activity per g liver decreased after partial hepatectomy, while PKM2 increased. Total PKL activity per 100 g body weight was restored to preoperational levels much more slowly than liver weight. During liver regeneration parenchymal cells acquired high PKM2 besides PKL activity. The isoenzyme outfit of non-parenchymal cells remained unchanged. Microdissection studies showed that PKL lost its normal perivenous to periportal gradient after partial hepatectomy and became evenly distributed within the liver acinus. PKM2 did not retain its even distribution, it became predominant in the periportal zone. Immunohistochemical staining revealed that after partial hepatectomy PKL was present in all parenchymal cells in an atypical non-zonal heterogeneous distribution. Normal specific activities as well as zonal and cellular distributions of both pyruvate kinase isoenzymes were restored 14-21 d after partial hepatectomy. During regeneration after 2/3 partial hepatectomy the liver loses its glucostat function as corroborated in this study by the decrease of the glycolytic capacity via the glucoregulatory PKL; this change of function is accompanied by a loss of PKL-zonation. This finding corroborates the view that zonation of carbohydrate-metabolizing enzymes is required only when the liver functions as a glucostat. The increase of PKM2 and the appearance of a zonal PKM2 heterogeneity are in line with the pattern of hepatocyte proliferation after partial hepatectomy.

Animals↗
PubMed1984

Phase relationship of the circadian rhythms of feed intake, caecal motility and production of soft and hard faeces in domestic rabbits.

In rabbits kept under 12:12 h light conditions, caecal contractions were recorded by implanted strain gauges or induction coils. In animals fed ad libitum caecal contraction frequency varied cyclically in phase with the circadian rhythm of feed intake. Both had their minimum during the time of soft faeces production. Thus all 3 functions seem to depend on the same circadian clock. The close link between caecotrophy and caecal contractions can, however, be upset by either time-restricted feeding or by fasting.

Animals↗
PubMed1983

Expression of the "split gene" cob in yeast mtDNA. Nuclear mutations specifically block the excision of different introns from its primary transcript.

Five nuclear mutants falling into five different complementation groups are shown to block the maturation of long form mitochondrial cob RNA at five different processing steps. At the same time they prevent complete processing of the oxi 3 RNA, thus exhibiting the same phenotype as mitochondrial box mutants (cyt b- and oxi 3-). The different nuclear factors in question have varying ranges of specificity for the removal of introns from cob RNA, from only one to at the most three introns. Two mutated nuclear elements are shown to be specific for the processing of introns present only in the long form cob gene. One such mutation shows, as expected, no deleterious effect on the processing of the short form cob RNA exchanged into the mutant via cytoduction. The role of nuclear coded factors in the possible translation or activity of introncoded products ("maturases") is discussed for two mutants. Striking parallels are found between diverse polypeptide products, presumably translated from accumulated cob RNA intermediates, in pet- and mit- mutants blocked in the excision of the same intron.

Base Sequence↗
PubMed1981

A new method for the isolation of rat liver acetyl-CoA carboxylase.

Rat liver acetyl-CoA carboxylase has been purified to homogeneity by a new method involving polyethylene glycol precipitation, and DEAE and Sepharose 4B chromatography. The final product displays a single band on SDS polyacrylamide gel electrophoresis of estimated molecular weight 240,000. This material contains 5.5 +/- 0.3 moles of alkali-labile phosphate per subunit and has a specific activity of 1.2 +/- 0.2 units per mg protein. As compared to previous purification procedures for the liver enzyme, this product has a higher phosphate content, lower specific activity, and an absence of major proteolysis. Trypsin digestion of 32P-labeled acetyl-CoA carboxylase from hepatocytes reveals that the 32P-labeled phosphorylation sites are extremely labile to proteolytic digestion. Potential modification of isolated liver acetyl-CoA carboxylase by proteolysis and/or dephosphorylation must be ascertained prior to in vitro enzymatic studies.

Acetyl-CoA Carboxylase↗
PubMed1980

[Surgical approaches to esophageal neoplasms].

After a short historical review of approach to the oesophagus, a case report of 42 resections of oesophagus carcinoma is done particularly in consideration of operative approach. Based on the experience of these cases and on considerations of principal and technical nature found in the pertinent literature, a guide idea of how approach oesophagus carcinoma is given.

Esophageal Neoplasms↗
PubMed1980

[Experiences with homologous umbilical cord veins in vascular reconstructive surgery].

12 homologous umbilical cord veins prepared according to the method of MINDICH from February to November 1978 were used as either femoro-femoral or femoro-popliteal bypass. 6 of the 12 implanted umbilical veins after an average of 4 months were still open and showed good results, whereas 4 were blocked by thrombosis due to bad outflow conditions or dissection. On two implants that had had to be removed, histological examinations were used, and these showed a destruction of the graft's wall. In contrast to the advantages of their problem-free availability and good technical suitability stands the destruction of these grafts observed by us and hence the questionable nature of tenacity in the receiver. Further experiences of longer duration dealing with this interesting subject of vascular substitute are needed.

Aged↗