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Biomedical subjects

Y V Bukin

Publications and source records attributed to Y V Bukin.

6 recordsLinked to original sources
PubMed1997

Decrease of ornithine decarboxylase activity in premalignant gastric mucosa and regression of small intestinal metaplasia in patients supplemented with high doses of vitamin E.

The effect of high doses of vitamin E (Vit.E; 400 units/ day) on ornithine decarboxylase (ODC) activity and regression of small intestinal metaplasia (SIM) was studied in a 1-year double-blind intervention trial. Biochemical and morphological parameters were estimated in 14 evaluable SIM patients of 18 in the Vit.E group and in 16 of 18 intestinal metaplasia patients enrolled in control group (placebo). In the control group, there were no statistically significant changes in Vit.E content in blood plasma, ODC activity, and the rate of SIM in multiple biopsies from antrum gastric mucosa. In the Vit.E group, after 6 and 12 months of intervention, the initial content of Vit.E in blood plasma increased from 6.4 +/- 0.9 up to 17.0 +/- 1.8 and 21.2 +/- 2.3 micrograms/ml, respectively, and the initial abnormally high activity of ODC, 62.6 +/- 7.8 units, decreased by 53 and 65%, respectively. Histological analysis of multiple biopsies, taken from the gastric antrum of patients supplemented with Vit.E, revealed that in 8 of 14 patients (57%) after 6 months and in 10 of 14 patients (71%) after 12 months, no signs of SIM were observed; gastroscopic dye procedure confirmed the regression of SIM in these cases and showed the presence of only small isolated stained areas identified as SIM.

Adult↗
PubMed1995

Effect of prolonged beta-carotene or DL-alpha-tocopheryl acetate supplementation on ornithine decarboxylase activity in human atrophic stomach mucosa.

The effect of beta-carotene and DL-alpha-tocopheryl acetate (alpha-TAc) on the activity of ornithine decarboxylase (ODC) in human atrophic stomach mucosa and intestinal metaplasia (IM) was studied in a double-blind intervention trial. Persons (227) with upper gastrointestinal symptoms and/or atrophic gastritis (AG) were examined. It was found that ODC activity in the biopsies of antral mucosa increased gradually from normal mucosa (7.2 +/- 1.8 units) to superficial gastritis (22.7 +/- 5.9 units) and to AG (54.2 +/- 6.9 units). Enzyme activity in cases of IM did not differ from atrophic mucosa without IM (56.1 +/- 8.0 versus 51.4 +/- 5.6 units; P > 0.05). For the intervention trial, 3 groups of 20 patients with AG were studied. Patients were supplemented daily for 1 year with beta-C (20 mg; group 1), alpha-TAc (55 mg; group 2), or placebo (group 3). No significant change in ODC activity was observed in placebo-treated subjects during 1-year follow-up. During the first 3 months, beta-C supplementation resulted in about a 50% decrease in ODC activity in atrophic mucosa. A moderate decrease in ODC activity of approximately 18% was observed after 6 months supplementation with alpha-TAc. The possible role of ODC in gastric carcinogenesis is discussed.

Adult↗
PubMed1993

Effect of beta-carotene supplementation on the activity of ornithine decarboxylase (ODC) in stomach mucosa of patients with chronic atrophic gastritis.

Increase of ornithine decarboxylase (ODC) activity is known to be associated with cell proliferation and, very likely, with tumour promotion. This prompted us to study the activity of ODC in gastric mucosa of patients with chronic atrophic gastritis that has been considered as a precursor of stomach cancer. Examination of 124 patients with this disease revealed the considerable increase in ODC activity in atrophic mucosa (29.8 +/- 2.9 vs 7.9 +/- 1.8 units in normal mucosa, p = 0.001). Supplementation of the patient's diet with beta-carotene (20 mg daily during 3 weeks) results in a statistically significant decrease in ODC activity in gastric mucosa. The data obtained confirm the possibility of application of ODC determination to the detection of early premalignant lesions and suggest the antipromoter activity of beta-carotene in gastric carcinogenesis.

Adult↗
PubMed1989

Cellular characterization of a new irreversible inhibitor of S-adenosylmethionine decarboxylase and its use in determining the relative abilities of individual polyamines to sustain growth and viability of L1210 cells.

S-(5'-Deoxy-5'-adenosyl)methylthioethylhydroxylamine (AMA) is an irreversible inhibitor of S-adenosylmethionine (AdoMet) decarboxylase, which is designed to bind covalently the pyruvate residue at the enzyme active site. In the present study the cellular effects of AMA were characterized for the first time in cultured L1210 leukaemia cells. At the approximate IC50 (concn. giving 50% inhibition; 100 microM), AMA decreased spermidine and spermine by more than 80% at 48 h while increasing putrescine more than 10-fold. As an indication of enzyme specificity, growth inhibition was fully prevented with exogenous spermidine. When compared with the irreversible inhibitor of ornithine decarboxylase, alpha-difluoromethylornithine (DFMO), at similar growth-inhibitory concentrations, AMA was less cytotoxic, as determined by colony-formation efficiency. In combination with AMA, DFMO eliminated the rise in putrescine and decreased growth in an additive manner. The near-total depletion of intracellular polyamine pools achieved with the drug combination provided an opportunity to examine the relative abilities of individual polyamines to support growth and viability. Of the three exogenously supplied polyamines, only spermidine fully sustained cell growth and viability at control values during incubations totalling 120 h. By contrast, spermine supported growth at 23% of control and viability at 8%. Putrescine was similarly ineffective, supporting growth at 13% of control and viability at 7%. The data indicate that, in L1210 cells, spermidine is apparently the preferred polyamine in growth-related functions and is capable of fully supporting cell growth by itself. However, because spermine and putrescine can also support growth to some extent, maximum interference with growth and viability is best achieved by strategies which deplete all three polyamine pools.

Adenosylmethionine Decarboxylase↗
PubMedDate not supplied

[Effect of the antibiotic D-cycloserine and its dimer on the activity of tyrosine aminotransferase in liver tissue of intact, adrenalectomized and hypophysectomized rats].

In a period of lowest day activity of tyrosine aminotransferase, within 6-8 days after bilatheral adrenalectomy, the enzyme activity was decreased by about 20% as compared with an adequate control. At the same time, within a day and seven days after hypophisectomy, in rat liver tissue the enzyme activity was increased, approximately two-fold as compared with the normal state. Within four hrs after intraperitoneal administration into intact fasting rats at a dose of 2-2.5 g per 1 kg of body weight D-cycloserine and its dimer caused an induction of tyrosine aminotransferase by 75% and 180%, respectively. Induction of the enzyme by D-cycloserine and its dimer was inhibited by actinomycin D; the phenomenon was not observed in adrenalectomized rats. Within a day after hypophisectomy D-cycloserine did not cause the induction of tyrosine aminotransferase in rat liver tissue; to the contrary, the dimer of D-cycloserine caused induction of the enzyme, comparable to the ACTH effect, in liver tissue of hypophisectomized rats.

Adrenalectomy↗