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Biomedical subjects

L Varga

Publications and source records attributed to L Varga.

At least 163 records · Page 9Linked to original sources
PubMed1979

Effects of prolonged administration of metiamide on serum gastrin, gastrin content of the antrum and gastric corpus, and G-cell population in the rat.

The effect of prolonged metiamide administration on serum gastrin, gastrin content of the antrum and gastric corpus, and G-cell population was studied in the rat. A single subcutaneous injection of metiamide (200 mg/kg) at the onset of 16 days of continous treatment with three daily injections was followed by a fivefold increase in serum gastrin level at 4 hr in fasted and at 4 and 6 hr in fed rats. After 16 days of metiamide, the fed rats showed a peak in serum gastrin level of the same magnitude as on day 1, but only at 4 hr. Two hours later, the levels decreased rapidly to basal values. In the fasted animals, the response to metiamide was reduced to a threefold increase at 2 hr. There was no difference in gastrin content of the antrum and gastric corpus nor in volume density of the G-cells after the prolonged treatment compared with the controls. It is concluded that in spite of rises in serum gastrin, prolonged metiamide medication has no effect on the gastrin content of the antrum and gastric corpus nor on the G-cell population in the rat. Furthermore, after prolonged treatment, metiamide-induced gastrin release is diminished.

Animals↗
PubMed1979

Ion content of synaptic vesicles.

Proton induced X-ray emission analysis measurements were performed to determine the P, S, K, Ca Fe, Ni, Cu and Zn ion content of presynaptic vesicles prepared from guinea-pig brain cortex. The number of different ions per single vesicle is calculated using the results of the additional protein content determinations. The ion contents of cholinergic and adrenergic vesicles are compared.

Acetylcholine↗
PubMed1979

Metabolism of C-terminal pentapeptide of gastrin in the rat. Part III. The catabolism of the BOC-pentapeptide and its distribution in the organs.

The metabolism of labelled BOC-14 C-glycine-pentapetide was investigated in rats, both in blood and urine. We report on the following findings: --radioactivity could be measured in the blood even after the disappearance of the bioactive- and immunoreactive pentapeptide. --the bulk of the radioactivity in the blood after 8 minutes originates from a metabolite which, after subsequent systematic chemical identification, proved to be the BOC-14C-glycine fragment of the pentapeptide. --the radioactivity in the urine comes entirely from this split product of the labelled pentapeptide --the organ distribution of radioactivity of labelled pentapeptide was checked after i.v. administration; 1 minute after the injection, most of the radioactivity was found in the liver, followed by the kidney, pancreas, jejunum and lung. After 1 hour, radioactivity could be detected only in the kidneys. It was concluded that the N-terminal amino-acid of the naturally occurring pentagastrin (glycine) remains linked to the BOC protecting group in the course of the catabolism of the molecule and this fragment is excreted in the urine.

Animals↗
PubMed1979

Effect of chloroquine on DNA synthesis in the skin of DLE patients.

Changes in the semiconservative and excision repair DNA synthesis were studied autoradiographically in the skin of 12 patients with discoid lupus erythematosus during Chloroquine treatment (500 mg/day for 8 weeks). The originally increased rate of the semiconservative DNA synthesis in the area of the skin lesions returned to the normal level simultaneous with clinical improvement. No effect on the excision reapir DNA synthesis could be detected.

Adult↗
PubMed1978

Repair of DNA damage in light sensitive human skin diseases.

Repair of UV-light induced DNA damage and changes in the semiconservative DNA synthesis were studied by in vitro autoradiography in the skin of patients with lightdermatoses (polymorphous light eruption, porphyria cutanea tarda, erythropoietic protoporphyria) and xeroderma pigmentosum as well as in that of healthy controls. In polymorphous light eruption the semiconservative DNA replication rate was more intensive in the area of the skin lesions and in the repeated phototest site, the excision repair synthesis appeared to be unaltered. In cutaneous porphyrias a decreased rate of the repair incorporation could be detected. Xeroderma pigmentosum was characterized by a strongly reduced repair synthesis.

Adult↗
PubMed1978

Pentagastrin analogs containing alpha-aminooxy acids, I. Synthesis of analogs substituted at the N-terminus.

Nine new pentagastrin analogs containing a free or protected alpha-aminooxy acid at the N-terminus were synthesized stepwise. Analogs containing leucyl, norleucyl, norvalyl, L- and D-2-aminodecanoyl residues instead of methionyl residue were also prepared. The peptides were synthesized by the active ester method with subsequent removal of the protecting groups. The purification of the end products was performed by crystallization or column chromatography on silica gel.

Amino Acid Sequence↗
PubMed1978

Pentagastrin analogs containing alpha-aminooxy acids, II. Simultaneous substitutions at the N- and C-terminus.

Twenty-seven new pentagastrin analogs containing free or protected aminooxy acids at the N-terminus and D-2-aminooxy-3-phenyl-propionic acid, L-(4-chlorophenyl)glycine, L- and D-phenylglycine, or L- or D-cyclohexyglycine instead of the C-terminal L-phenylalanine and analogs extended by aminooxyacetic acid at the C-terminus, were synthesized stepwise. The end products were purified by chromatography on DEAE-cellulose or silica gel.

Amino Acid Sequence↗
PubMed1978

Pentagastrin analogs containing alpha-aminooxy acids, III. Biological studies and structure-activity relationships.

The stimulation of gastric acid flow by thirty-six new pentagastrin analogs administered intravenously, intrajejunally and intrarectally was determined in rats. Some of the analogs are several times more active than the pentagastrin (Peptavlon, I.C.I.) used as control. Unlike the control, some analogs are absorbed in active form from the jejunum. The N-terminal substitution with alpha-aminooxy acids seems to increase the gastric secretory response, probably by improving the enzymatic resistance of the molecule to various enzymes. None of the analogs tested significantly inhibit the gastric acid output in rats induced by pentagastrin. Structure-activity relationships are discussed.

Animals↗
PubMed1978

Tritium release from Ti-T layers in air, in aqueous media and in animal experiments.

In connection with Ti-T incorporation hazard to which operators of neutron generators are exposed the release of tritium from Ti-T preparations of different ages was studied in experiments carried out in air, in aqueous media and in living animals. Samples were prepared with activities from 10 to 30 mCi and the effect of storage on the tritium release rate was also observed. In 250 days a fraction of 10(-3) of the tritium activity was absorbed by aqueous liquids. In air the release varied from 10(-6) to 10(-7) per hour. The Ti-T samples of different ages, introduced surgically into the abdominal cavity of rats, showed the tritium release rate to decrease with time. The tritium activity observable in the circulation was 5 to 6 orders of magnitude smaller compared with the introduced value. The observations permit the inference that in the case of Ti-T incorporation only a minor fraction of the tritium burden can be assessed from the activity measured in the urine.

Air Pollutants, Radioactive↗
PubMed1978

Magnetic property of the nerve.

An electromagnet of inhomogeneous magneticfield has been used to measure the magnetic susceptibility of the frog's nerve. Specimen of frog sciatic nerve were attached to a thin tungsten wire hanging into the inhomogeneous magnetic field, and from the deviation of this pendulum from the perpendicular position the magnetic susceptibility of the nerve has been determined to be -0.8 . 10(-6) cm3g-1 in a good agreement with the known magnetic property of the constituents of the nerve.

Animals↗