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A S Loktionov

Publications and source records attributed to A S Loktionov.

16 recordsLinked to original sources
PubMed1991

[Activation of the Ha-ras oncogene in tumors induced in mice by transplacental exposure to 7,12-dimethylbenz(a)anthracene].

A study of tumors induced in mice by transplacental exposure to 7,12-dimethylbenz(a)anthracene (DMBA) alone or in combination with postnatal tissue-specific promotion showed skin and liver tumor development to be associated with cellular Ha-ras oncogene activation in a large percentage of cases. As shown by Xba I RFLP, oncogene activation was caused by T for A substitution at the second position of codon 61. The said mutation was traced in DMBA-induced tumors of the liver alone but not in spontaneous hepatomas. The results of the study showed the role of oncogene activation in cancer development to be tissue-specific.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1991

[Presence of specific mutation of Ha-ras oncogene in skin tumors of mice induced under different experimental conditions].

The mutation was revealed with substitution of A for T in the second position of the 61 Ha-ras oncogene codon in the DNA of 31 skin tumours (26 papillomas and 5 carcinomas) and in 23 mice treated with 12-O-tetradecanoyl phorbol-13-acetate (TPA). Part of these mice were F progeny (n-6) and F progeny (n-4) following DMBA administration during pregnancy, another part F progeny (n-5) following ENU action on males prior to mating, the rest mice (n-3) did not undergo additional actions. The mutation under study was revealed only in 3 out of 5 papillomas and in all 5 carcinomas of mice subjected to DMBA administration during pregnancy.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

Effect of low-molecular-weight factors of thymus and pineal gland on life span and spontaneous tumour development in female mice of different age.

Female SHR mice, aged 3.5 or 12 months, were exposed monthly to 5-day long courses of subcutaneous injections of 0.1 mg thymus-derived or pineal gland-derived polypeptide factors (TF and PF, respectively) or 0.9% sodium chloride solution (control). PF treatment increased life span of both young and middle-aged mice by 20% and 17%, respectively, and TF increased the life span only in young mice. Both factors when administered to young mice caused a decrease in both overall tumour incidence and incidence of mammary adenocarcinomas (TF, 1.8-fold decrease; PF, 2.6-fold decrease). TF administration to mature mice did not produce any antitumour effect, whereas PF possessed certain anti-tumour activity, but the response was far less pronounced than in young animals. The results obtained give additional evidence of the geroprotective and anti-tumour effect of thymus and pineal gland-derived peptide factors. The mechanisms of action of TF and PF and perspectives of clinical use of these agents as geroprotectors are discussed.

Age Factors↗
PubMed1988

Influence of host age on lung colony forming capacity of injected rat rhabdomyosarcoma cells.

Intravenous administration of RA-2 transplantable rhabdomyosarcoma cells produces development of metastatic tumour cell colonies in the lungs of host rats. After administration of 2 X 10(3), 5 X 10(3) or 10 X 10(3) RA-2 cells, different patterns of dependence of the number of metastatic clones in the lungs on injected cell number have been observed. The numbers of tumour cell colonies were shown to be highest in immature (1-month-old) and old (15-month-old) female rats compared to middle-age groups (3- and 12-month-old). A similar age-related pattern was observed in male rats. Analysis of the results obtained has revealed positive correlation between tumour cell colony numbers and both somatomedin activity and proliferation rate of neoplastic tissue.

Age Factors↗
PubMed1984

[Morpho-functional characteristics of the mast cells of the subcutaneous connective tissue in rats with arterial hypertension].

Mast cells of the rat subcutaneous connective tissue were studied in experimental hypertension. An increase was discovered in the degranulation of the cells in rats with spontaneous and adrenal-regenerative hypertension. These animals demonstrated a rise in the number of immature cells with a relatively low content of serotonin. The changes described are believed to be linked with arterial pressure elevation.

Animals↗
PubMed1981

[Autoradiographic study of hormonal regulation of proliferating golden hamster uterus cells during postnatal ontogeny].

Study of the effects of octestrol, 17-hydroxyprogesterone caproate and tamoxifen on uterine cell proliferation in golden hamsters aged one to twenty days has shown the existence in the uterine epithelium of two cell populations with varying sensitivity to sex hormones. The cells of uterine glands being formed by day 12 of postnatal ontogenesis were found to be insensitive to the proliferation-inhibiting effect of progesterone and little sensitive to the proliferation-stimulating action of the estrogen. The epithelial cells lining the uterine cavity show a high sensitivity to sex hormones. The absence of changes in proliferative activity of the epithelial cells exposed to tamoxifen allows a suggestion that ontogenetic changes in the proliferative activity of the uterine cells do not depend on the presence of endogenous hormones.

17 alpha-Hydroxyprogesterone Caproate↗
PubMed1981

[Use of the Elektronika-T3-16M special-purpose computer for the automatic processing of cytophotometric and cytofluorimetric data].

A system has been proposed to provide the automatic analysis of data on: a) point cytophotometry, b) two-wave cytophotometry, c) cytofluorimetry. The system provides the input of the data from a photomultiplier to a specialized computer "Electronica-T3-16M" in addition to the simultaneous statistical analysis of these. The information on the programs used is presented. The advantages of the system, compared with some commercially available cytophotometers, are indicated.

Computers↗
PubMed1981

[Quantitative kinetic study of the histochemical reaction to peroxidase in salivary gland and uterine cells of golden hamsters].

The kinetics of diaminobenzidine reaction for peroxidase has been studied using cryostat sections of salivary gland and uterus of the golden hamster. It was demonstrated that the inhibition of the initial velocity of the reaction in salivary gland occurred at hydrogen peroxide concentration in the reaction medium being 5.10(-3) M or higher. On the other hand, the inhibitory action of hydrogen peroxide excess on the uterine peroxidase activity was observed at H2O2 concentrations higher than 1.10(-3) M. KM values for diaminobenzidine, determined for salivary gland and uterine peroxidases, were 2.3.10(-3) M and 3.5.10(-3) M, resp; KM values for H2O2 were 1.1.10(-4) M and 2.5.10(-5) M, resp. Kinetic difference of salivary gland and uterine peroxidases obtained in this study support the view on the organ specificity of peroxidases.

3,3'-Diaminobenzidine↗
PubMed1980

[Quantitative histochemical study of alkaline phosphatase isoenzymes in the uteri of ovariectomized golden hamsters during estrogenization].

The activity of two isoenzymes of alkaline phosphatase was studied in the uteri of ovariectomized golden hamsters. Animals belonging to different groups were daily injected with 10 micrograms of estrogen (octoestrol) once, for 4 and 16 days. The estrogen did not affect the overall activity lf alkaline phosphatase in the uterine luminal epithelium, but decreased the enzyme activity in stroma. Moreover, it was found that prolonged estrogen treatment increases significantly the proportion of alkaline phosphatase isoenzyme of the intestinal type in the uterine luminal epithelium.

Alkaline Phosphatase↗
PubMed1980

[Uterine response of golden hamsters to estrogenic stimulation in postnatal ontogeny].

The proliferative activity of the cells of uterine epithelium and stroma of the developing golden hamsters and the activity of acid phosphatase isozymes in these tissues was studied. The dynamics of changes of these indices during the normal development and upon estrogenic stimulation was followed. The uterine cells were shown to react to estrogenic stimulation was followed. The uterine cells were shown to react to estrogenic stimulation by the increase of proliferation from the first days of postnatal development. Characteristic changes in the ratio of the acid phosphatase isozymes in the epithelial cells in response to estrogenic stimulation appeared in the 2nd week of postnatal development only. The definite level of differentiation of cells-targets appears to be indispensable for the realization of certain specific effects of the hormone.

Animals↗
PubMedDate not supplied

[Mutations in the 61st codon of the c-Ki-ras oncogene during transplacental lung tumor induction in mice and their difference in spontaneous and induced tumors].

DNA isolated from lung and liver tumor which were induced in CD-1 mice by transplacental treatment with 7,12-dimethylbenz(a)anthracene (DMBA) or developed spontaneously was analyzed for the presence of Ha- and Ki-ras oncogene codon 61 mutations. The A to T transversions at the second position of Ha-ras codon 61 were revealed only in liver tumors of DMBA-exposed animals, whereas only Ki-ras mutations occurred in both spontaneous and induced tumors of the lung. A to T mutations at the second position of Ki-ras codon 61 or non-identified yet mutations at the third position of the same codon were shown to be related to DMBA treatment. Thus both tissue and carcinogen specificity of ras oncogene activation was clearly demonstrated.

9,10-Dimethyl-1,2-benzanthracene↗