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Biomedical subjects

G Koch

Publications and source records attributed to G Koch.

At least 19 recordsLinked to original sources
PubMed1979

Alterations in translational control mechanisms in Friend erythroleukemic cells during DMSO induced differentiation.

Induction of erythroid differentiation in Friend erythroleukemia cells causes a reduction in the rate of protein synthesis and a prolonged growth cycle of the cells. A study of the relative translational efficiencies (RTE) of viral mRNAs and selected host cell mRNAs revealed unexpected low RTEs of the mRNA coding for the gp70 protein and RTE of the mRNA coding for the p30 protein. The RTEs of viral and of some host mRNAs show significant changes during differentiation. The rate of synthesis of corresponding proteins are altered non-coordinately, indicating transcriptional and/or posttranscriptional regulation of mRNA, as well as amplified regulation at the level of translation of mRNA.

Cell Differentiation↗
PubMed1979

Partial purification of tumour-specific transplantation antigens from methylcholanthrene-induced murine sarcomas by immobilized lectins.

Plasma membranes isolated from two immunogenic, non-cross-protecting, MC sarcomas were shown to retain the specific rejection antigens of whole cells as well as serologically detected H-2 antigens. Solubilization of the membranes with sodium deoxycholate gave quantitative release of H-2 and retained the rejection specificity of the tumour from which it was derived. Polyacrylamide-gel electrophoresis (PAGE) showed no extensive degradation of membrane components during solubilization. The solubilized TSTAs were further characterized and purified on columns of 4 different lectins immobilized on sepharose beads. TSTA from both tumours bound to WGA but not to Con A, LCH or RCA columns. Specific activity was retained after elution from the WGA column. Serologically detectable H-2 bound to the Con A and LCH columns only. Clear separation of H-2 from TSTA activity was thus obtained. Furthermore the WGA-binding material represents a source for further purification of TSTA molecules in order to explore the basis for their diversity.

Animals↗
PubMed1979

Type-C virus antigen detection in co-cultures of human leukaemic bone marrow and dog cells.

Bone marrow of leukaemic patients, non-leukaemic patients and normal individuals were co-cultivated with the canine cell line A7573. These co-cultures were screened for retrovirus antigens by means of the indirect cytoplasmic immunofluorescence assay (IFA). Rabbit antisera directed against the major structural protein (p30) of woolly monkey (simian) sarcoma leukaemia virus (grown in human lymphoid cells) and Rauscher murine leukaemia virus were used for testing. After 2 months in culture, 6 of 17 co-cultures containing cells from leukaemic patients showed positive staining in the IFA with the anti-simian virus serum. In control dog cells fluorescence was never observed. Five of the six positive cultures were derived from leukaemic children. One of 12 co-cultures of the non-leukaemic group and one of nine normal bone marrow co-cultures were positive with the simian virus antiserum. None of the 38 co-cultures stained positive in the IFA with Rauscher virus antiserum. Absorption of the simian virus antiserum with calf serum or mouse mammary tumour virus had no dramatic effect in the IFA on positive control cells or on cells of a positive co-culture. However, absorption with purified simian virus (grown in rat cells) completely abolished these fluorescence reactions. The results provide evidence that simian sarcoma-leukaemia virus related information was present in the original bone marrow samples and that co-cultivation with permissive mammalian cells enabled the detection of virus footprints.

Adult↗
PubMed1979

Effect of flouride varnish (Duraphat) treatment every six months compared with weekly mouthrinses with 0.2 per cent NaF solution on dental caries.

Recent studies have shown a high fluorine uptake in the enamel and a considerable caries reduction following the application of varnished containing fluoride. As the application is easy to carry out it may in certain situations serve as an alternative to other topical fluoride school programmes. The aim of the present study, therefore, was to compare the caries increment in schoolchildren exposed to a fluoride varnish (Duraphat) every six months and in children receiving the conventional weekly fluoride mouthrinsing programme with 0.2 per cent sodium fluoride over a two-year period. Two hundred 14-year-old children, divided into one test and one control group took part in the study. They were clinically and radiographically examined every year. Preexperimental data revealed no differences between the groups. During the experimental period the children in the fluoride varnish group developed a statistically significant lower number of new carious lesions compared with those in the mouthrinsing group. The difference in caries increment was about 30 per cent. Further clinical studies to compare the effects of various topical fluoride programmes are recommended.

Adolescent↗
PubMed1979

Cardiovascular dynamics after acute and long-term alpha- and beta-adrenoceptor blockade at rest, supine and standing, and during exercise.

1 After acute intravenous administration labetalol reduced mean values for BP, total peripheral resistance, heart rate and cardiac output. All changes were more pronounced during bicycle exercise. 2 After a mean duration of 20 months' treatment with oral labetalol the haemodynamic findings were broadly similar except for a more marked reduction in the total peripheral resistance and cardiac output had returned to pretreatment level due to an increased stroke volume which had counter balanced the reduction in heart rate. These changes occurred at rest, in the erect position and during exercise but the reductions in BP and peripheral resistance were most marked during exercise. 3 Left ventricular filling pressures and stroke volume/filling pressure ratios were not significantly altered after intravenous labetalol compared with pretreatment values. 4 Systolic BP x heart rate product was lowered particularly during exercise after both intravenous and oral labetalol. 5 After long-term oral labetalol, the most striking haemodynamic change was in the elevated resting stroke volume supine and standing.

Adrenergic alpha-Antagonists↗
PubMed1979

[Indications for surgery and operability from the point of view of the surgeon (author's transl)].

The decision as to surgical intervention and operability must also take into account somatic, personal, psychosomatic and social factors. The advances made in medical science have added to rather than detracted from the difficulties of the problem. Although the final decision rests with the surgeon the indications as to surgical intervention and operability present problems which demand interdisciplinary co-operation, first with the general practitioner, then, after admission to hospital, with the various specialists and subsequently again with the general practitioner.

Decision Making↗