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M A Shabanov

Publications and source records attributed to M A Shabanov.

At least 19 recordsLinked to original sources
PubMed2004

[Identification of the hereditary variants of skin melanoma].

The identification of hereditary variants of cutaneous melanoma and analysis of the role of hereditary factors and syndromes predisposing to cutaneous melanoma were carried out. The involvement of individual nevus phenotypes in the development of this disease was determined. Based on a survey of recent molecular biological data and our studies, the etiological and genetic heterogeneity of cutaneous melanoma is reported. In relatives of patients with cutaneous melanoma and persons with multiple pigmented nevi, the malignant tumors proved to be differentiated in the direction of the neural crist tissues and/or derivatives of cutaneous mesenchyma. Based on the evidence obtained, the approaches have been developed to formation of risk groups for the purpose of early diagnostics of cutaneous melanoma.

Diagnosis, Differential↗
PubMed2003

[Analysis of mutations in the RET proto-oncogene in patients with medullary thyroid tumor].

The spectrum of mutations of the RET protooncogene was analyzed in Russian patients with inherited or sporadic medullary thyroid carcinoma (MTC). Four RET exons (11, 13, 15, and 16) were subjected to molecular analysis, and mutations were revealed and identified in 47.4% (9/19) patients with sporadic MTC. In total, six mutations (including three new ones) were observed. The most common mutation affected codon 918 to cause substitution of methionine with threonine and accounted for 31.6% alleles. Analysis of exons 11 and 16 revealed four mutations in patients with inherited multiple endocrine neoplasia type 2 (MEN 2). Mutations were found in each patient. Thyroidectomy was performed in four asymptomatic carriers of RET mutations from three MET 2A families (in two families, affected relatives had bilateral pheochromocytoma). In two patients, analysis of the surgery material revealed MTC microfoci in both lobes of the thyroid gland. The results provide the ground for constructing a bank of genetic information on Russian MTC patients with the clinically verified diagnosis.

Adolescent↗
PubMed2001

Three novel mutations in the RET proto-oncogene.

Medullary thyroid carcinoma (MTC) occurs as a sporadic tumor or in connection with inherited cancer syndromes of multiple endocrine neoplasia type 2 and familial MTC. Missense RET proto-oncogene mutations and small in-frame deletions are found in most of the cases. In a significant amount of sporadic MTC cases somatic mutation at codon 918 (exon 16), or at codons 609, 611, 618, 620 (exon 10), or codons 630, 634 (exon 11) appear. We report here on three new somatic cell missense mutations of the RET proto-oncogene associated with sporadic MTC. In one tumor mutation at codon 922 TCC(Ser)-->TTC(Phe) in exon 16 was found. In another tumor two mutations at codons 639 GCA(Ala)-->GGA(Gly) and 641 GCT(Ala)-->CGT(Arg) in the exon 11 were observed. Allele-specific PCR followed by sequencing demonstrated the presence of both mutations at the same allele.

Base Sequence↗
PubMed1998

[Cytomorphological diagnosis of granulosa cell tumor of the ovary].

The cytology of granulosa cell tumor in children and adults is studied. Cytological smears of ascitic fluid and fresh tissue smears were examined. The tumor was diagnosed in 9 patients aged 11 to 73 years. All patients had symptoms of hyperestrogenia. Adequate treatment of the condition requires the tumor to be differentiated from other tumors (thecoma, low-grade and small-cell carcinomas, carcinoid, yolk-sac tumor, and lymphoma) before or during surgery.

Adolescent↗
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↗
PubMed1991

[The role of embryoid bodies in the development of germinogenous tumors of complex structure and of the teratoma].

250 germinal gonadal and extragonadal tumors were studied in children and adolescents under 16 years of age. Germinal tumours of complex structure were found in 42 patients and in 36 of them embryoid bodies of various types (full, not-full, amorphous) were distinguished. Certain features were revealed indicating the development of the immature teratoma by means of maturation of preexisting embryoid bodies. The arguments in favour of complex germinal tumour development due to the loss of maturation and differentiation capacity of one or several structural elements of the embryoid bodies are presented. The observation of mature, immature embryonal tissues and proliferating elements of the embryoid bodies in the composition of one and the same tumour may be explained by different biological potency of individual clones of atypical and primordial germinal cells which are the source of the development of these tumours.

Adolescent↗
PubMed1990

[Features of the histogenesis of testicular yolk sac tumors in children].

32 cases of a yolk sac tumour of the testis in children aged up to 5 years underwent retrospective morphological study. Foci of proliferation of activated gonocytes identical to the type A spermatogonia with clear nuclei and the type B spermatogonia characterized by a negative PAS-reaction and reaction to alpha-fetoprotein are observed in the seminiferous tubules surrounding a tumour. Besides this areas of the primordial germinogen cell generation are found among the cells lining the system of labyrinths and channels of the yolk sac tumour. A new hypothesis of the yolk sac tumour histogenesis in the child testis is put forward--namely, through the transformation of the activated gonocytes in the seminiferous tubules into their "somatic" phase, i.e. into the yolk sac elements from which they originate. Likewise, the scheme is suggested reflecting a cyclic character of the germinogenic cells in ontogenesis. This scheme allows visual representation of the process of the parthenogenetic development of germinogenic tumours.

Cell Division↗
PubMed1989

[A comparative study of delayed hypersensitivity due to mycobacteria and their isolated protein fractions].

The role of intracellular protein fractions, isolated from M. tuberculosis virulent strains in the process of the electrophoretic separation, in the development of delayed hypersensitivity reactions has been studied. Low reactogenicity of protein fractions has been established on the basis of the development of faint immunopathological reactions in sensitized animals. High-molecular fraction 1 may be used as a sensitive preparation for the differentiation of individual mycobacterial species.

Animals↗
PubMed1988

[Extradural sacrococcygeal myxopapillary ependymoma].

Histological and electron microscopic evidence has been obtained on a rare tumor--extradural sacrococcygeal myxopapillary ependymoma which was detected in two boys. A 5-year-old had a malignant recurrent tumor localized presacrally and metastatic to the lungs. The other boy aged 9 developed a benign subcutaneous tumor.

Child↗
PubMed1987

[Hepatoblastoma cells producing alpha-fetoprotein: morphometric, immunohistochemical and electron microscopic studies].

Morphometric, immunohistochemical, and electron-microscopic studies were undertaken in an attempt to identify the types of hepatoblastoma cellular elements responsible for the synthesis of alpha-fetoprotein (AFP), and to see how they may relate to serum AFP levels and the metastatic spread and prognosis of the hepatoblastoma. Morphometric studies of 21 hepatoblastomas with statistical treatment of the results revealed a moderately strong reliable correlation of the AFP serum titer with the volume ratio of embryonal tumor cells and with that of those tumor elements of endodermal hepatic diverticulum which are similar to the latter cells with regard to degree of differentiation. Also, a consistent, reliable negative correlation was demonstrated between serum AFP titer and the volume of fetal hepatoblastoma cells. The volume ratio of stromal elements was found to be subject to chance variations and not to correlate with serum AFP level. Immunohistochemical and electron-microscopic studies confirmed the morphometric findings and showed AFP synthesis to be effected by poorly differentiated hepatoblastoma cells--by endodermal hepatic diverticulum elements at first and by embryonal and intermediate tumor cells later--and to decrease as the liver tumor cells differentiate further. It is concluded that a high serum AFP level is, generally, an indication that the hepatoblastoma is an extensive one and consists of poorly differentiated cells so that the prognosis is unfavorable.

Carcinoma, Hepatocellular↗
PubMed1986

[Histological and ultrastructural characteristics of yolk sac tumors of gonadal and extragonadal localization in children].

30 yolk sac tumours of a gonadal and extragonadal localization in children (19 testis tumours, 5 ovarian tumours, 6 tumours of extragonadal sites: presacral, sacralcoccygens, gluteal, retroperitoneal regions, vagina, liver) are studied histologically, in 8 cases electron-microscopically as well. The description of main histological and ultrastructural features that either may be used for differential diagnosis or may indicate the degree of tumour cells differentiation is presented.

Adolescent↗
PubMed1986

[Comparative morphological studies of cervix cancer and adjacent tissue following preoperative intracavitary contact therapy using Cf-252 or Co-60].

The effects of Cf-252 and Co-60 radiation have been compared by investigating radiation response and radiation pathomorphosis of the cervical carcinoma and surrounding normal tissue. The effectiveness of radiotherapy treatment was evaluated by comparison of Cf-252 and Co-60 irradiated patients (each arm 18 patients) with a non-irradiated control group (15 patients), suffering from epithelium carcinomas of the cervix uteri. The total dose in point A was 60 isoGy in either case given in 3 fractions at 28 days using the after-loading units "ANET" (neutrons) and "AGAT V" (gamma). Two to three weeks after irradiation, extended extirpation of the uterus and its adnexa was performed. The therapeutic effect was strongest in both comparative groups with superficially located exophytic forms of the cervical carcinoma and with carcinoma in situ. With invasive growth forms, signs of therapeutic pathomorphosis were found in both groups predominantly in the superficial tumor areas. However, the extent of the remaining tumor complexes was much greater with Co-60 than with Cf-252 radiation. Adenocarcinomas were more sensitive to Cf-252 independently of the invasion depth of the tumor. The observed alterations in the surrounding normal tissue of the uterus, both in the immediate proximity of the Cf-252 source (endometrium) and at some distance (myometrium, perimetrium) reflect the more severe alterations following irradiation as compared with Co-60. The lower values of the volume density of the tumor parenchyma remaining after radiotherapy and the high damage index (95.5%) give evidence for the pronounced biological and therapeutic effectiveness of high dose rate Cf-252-radiation. They allow to expect improvement of late results in the treatment of patients with epithelium carcinoma of the cervix uteri, and it seems to be reasonable to make further studies in that direction.

Adenocarcinoma↗
PubMed1986

[Morphology of cancer of the cervix uteri and surrounding tissues after preoperative intracavity therapy with high-energy 252Cf radiation sources and 60Co].

Comparative morphological study of uterine cervix carcinoma in 21 patients after a intracavity radiotherapy by 252Cf and in 18 patients treated with 60Co is performed. Total focal dose in a point A in both cases was 30 Gy. Morphometric study with the calculation of a volume correlation between stroma and tumour parenchyma in the two main groups and a control (untreated) group with a subsequent determination of a damage index has been done for the assessment of therapy. Both sources of radiation had an approximately similar efficiency in the treatment of superficial exophytic forms of tumour growth. 252Cf was biologically more efficient in the treatment of the deeply invasive forms of growth. The index of damage in 252Cf and 60Co was 96.5 and 84, respectively. Likewise the alterations in the surrounding normal uterine tissues after the intracavity irradiation with fast neutrons were more pronounced than those provoked by 60Co.

Adenocarcinoma↗