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Biomedical subjects

L Varga

Publications and source records attributed to L Varga.

At least 181 records · Page 10Linked to original sources
PubMed1976

The development of a reliable and sensitive bioassay for gastrin in body fluids.

The sensitivity and reliability of the Ghosh and Schild rat stomach preparation was improved by implantation of bulky intragastric cannulae, recirculation of the perfusate and measurement of conductivity instead of pH. With these procedures, the threshold values for gastrin I were in the range of 1-2 ng. In attempts to increase the sensitivity further it was shown that neither vagotomy nor antrectomy influenced the sensitivity of the method. The threshold values were not lowered by attempts to reduce gastrin metabolism through nephroligature or small bowel resection. Although rats fitted with portacaval shunts did raise the threshold, the limited increase in sensitivity was also achieved by selecting the rats that gave an initially high response to a test dose of gastrin thus avoiding the complicated shunt operation. The assay procedure enabled statistically valid measurements of gastrin in plasma and from tumour extracts from patients suffering from the Zollinger-Ellison Syndrome to be assayed using a 2 + 2 block design.

Analysis of Variance↗
PubMed1976

Studies on the radiosensitivity of the function of the Golgi complex.

The uptake of 3H-glucosamine into primary human-embryo fibroblasts and into the Golgi-rich fraction isolated from liver of mice labelled in vivo was studied, after various doses of X-radiation, by autoradiography and biochemical methods. A dose of 90 rad resulted in an increased precursor uptake in interphase cells at 24 hours and in mitotic cells at 48 hours after irradiation; 226 rad had virtually no effect on the grain counts of interphase cells, but reduced the labelling of mitotic forms. The characteristic intracellular localization of the grains were not influenced by these doses. Although no immediate radiation-induced reaction could be observed in liver cells either, significant stimulation of the 3H-glucosamine incorporation was measured in isolated Golgi-rich fractions 24 hours after whole-body irradiation with 90, 450, or 905 rad. This phenomenon is discussed as a part of the somatic regeneration of membrane structures.

Animals↗
PubMed1976

The distribution of 3H-gastrin and 14C-pentagastrin in the blood and lymph of rats.

3H-gastrin (0.83 mug/rat) or 14C-glycine-pentapeptide amide (100 mug/rat) were injected into the femoral vein in various groups of rats and radioactivity was measured in the arterial blood plasma and thoracic duct lymph in consecutive 5--10 min. periods for 60 minutes. Radioactivity excreted in the bile for 30 minutes was injected into the blood and lymph was followed for 120 minutes. It has been observed that labelled gastrin or pentagastrin activity reaches its peak in the plasma in the 5th minute after intravenous injection. Next, activity in the plasma decreased after the injection of labelled gastrin, but remained unchanged after the injection of labelled pentagastrin. In the lymph, radioactivity reached its peak value between 5--15 min. after the injection of the labelled hormones. This peak value was two- to threefold of plasma radioactivity measured at the same periods. After the intravenous injection of labelled pentagastrin radioactivity was excreted in the bile; injecting this radioactive bile into the jejunal lumen, radioactivity was reabsorbed mainly into the blood circulation.

Animals↗
PubMed1976

The significance of the combined dexamethasone-HCG test for the assessment of hyperandrogenism.

The combined dexamethasone-HCG test was employed in 57 patients with excessive androgen secretion in order to differentiate the Stein-Leventhal syndrome from other disorders associated with increased androgen production. The patients were classified according to the test results. All except two of the patients gave a test result typical for the Stein-Leventhal syndrome.

17-Ketosteroids↗
PubMed1976

Metabolism of the gastrointestinal peptide hormones.

Results of investigations on the metabolism of gastrin, pentagastrin, cholecystokinin and secretin are discussed on the basis of data in the literature. Own results concerning the metabolism of 14C-pentagastrin are also described, out of which the significance of a biologically inactive metabolite is emphasized. This metabolite can be demonstrated in the circulation, and is excreted in the urine. As judged from the present state of investigations, this metabolite has a crucial importance in the metabolism of pentagastrin.

Animals↗
PubMed1975

Effect of X-irradiation on 3-H-glucosamine uptake by human embryo fibroblasts.

The incorporation of 3-H-glucosamine into unirradiated and X-irradiated (905 rad) cultures of human embryo fibroblasts was studied by light microscopic, autoradiographic and biochemical methods in pulse-chase experiments. The precursor was 3-H-glucosamine. In unirradiated cells the grains appeared in various subcellular regions in a particular order: at first over the Golgi complex, then over the whole cytoplasm and finally at least some of the labelled macromolecules emerged from the cell. The radioactivity emerging from the cell appeared to be protein bound. Due to the effect of irradiation, the uptake of 3-H-glucosamine by the interphase cells was considerably decreased. The amount of radioactivity per cell indicated both the inhibition of cytoplasmic segregation and migration of labelled macromolecules from the cell. In the mitotic figures appearing after the release from radiation-induced mitotic block (approximately 30 hours after irradiation), the grain counts were still considerably lower than the controls. The functional and structural radiation injury of the Golgi-complex was suggested by the less well-defined sequence of localization of radioactive macromolecules than in control cells.

Autoradiography↗
PubMed1975

Pituitary and ovarian response patterns to stimulation in the postpartum and in galactorrhea-amenorrhea. The role of prolactin.

In order to assess the action of prolactin on the puerperal pituitary-ovarian resistance to physiologic stimulation, a study was conducted in 27 women divided into three groups. Group I: 9 postpartum women who did not wish to breastfeed their infants and received 2.5 mg bromocriptin (CB 154) twice daily for 14 days starting immediately after delivery; Group II: 9 normally lactating mothers; and Group III: 9 women with hyperprolactinemia associated with amenorrhea. The three groups underwent stimulation with LHRH and Pergonal 500. Results indicate lack of prolactin dependence in the pituitary-ovarian resistance of the puerperium. The possible mechanisms involved in the anovulatory period of lactation are discussed.

Adult↗
PubMed1975

Direct isolation of mycoplasmas and acholeplasmas from sera and kidneys of calves.

Kidneys and sera of calves from various farms and primary kidney tissue cultures were tested for mycoplasma and acholeplasma contamination. Altogether 24 strains belonging to Mycoplasma arginini and Acholeplasma axanthum were isolated from tissue cultures, kidneys and sera. The same species were detected from lungs and peribronchial lymph nodes of calves, together with A. laidlawii, A. modicum and M. bovirhinis species. There was a close correlation between the mycoplasma content of tissue cultures, sera and kidneys and the clinical picture observed in the farm, as well as between the quality of tissue cultures and the mycoplasma content of organs, sera and tissue cultures.

Animals↗
PubMed1975

[Biochemical and serological study of mycoplasma isolated from milk in cases of mastitis].

Studied were biochemically and serologically a total of 10 Mycoplasma cultures isolated from milk of mastitis-affected cows (clinical and subclinical forms). The organisms were differentiated as belonging to Mycoplasmataceae (M. alkalescens species), and Acholeplasmataceae (A. laidlowii species). Demonstrated was also the presence of mixed cultures including M. alkalescens and A. laidlawii. The organisms specified as A. laidlowii showed atypical properties so far as some biochemical indices were concerned.

Animals↗
PubMed1975

[Differential staining of the chromosomes in transplanted ascites tumors in mice (in connection with the discussion on the existence of the NK/Ly strain)].

When studying the Q-, G-, and C-bands, the character of acrocentric chromosomes' bands was found to be varying even within the same tumor. However, the bands of the markerchromosomes A and B coincide in NK/Ly and in the Ehrlich--Lettres tumors. With the aid of staining for revealing C-bands, the acrocentric markers "cc" and "ac" common for both tumors, were first noted. This corroborates the opinion of the replacement of NK/Ly by the Ehrlice-Lettres tumor.

Animals↗