[Construction and characteristics of transgenic tobacco Nicotiana tabacum L. plants expressing CYP11A1 cDNA encoding cytochrome P450scc].

In steroidogenic animal tissues cytochrome P450scc catalizes the conversion of cholesterol into pregnenolone, a common metabolic precursor of all steroid hormones. To study the possibility of functioning of mammalian cytochrome P450scc in plants and the mechanism of its integration in the plant steroidogenic system, transgenic plants of tobacco Nicotiana tabacum L. were developed carrying cDNA of CYP11A1 encoding cytochrome P450scc of bovine adrenal cortex. Pregnenolone, a product of the reaction catalyzed by cytochrome P450scc, was discovered in the steroid-containing fraction of transgenic plants. Transgenic plants are characterized by a reduced period of vegetative development (early flowering and maturation of bolls) and increased productivity. The contents of soluble protein and carbohydrates in leaves and seeds of transgenic plants are essentially higher than the contents of these components in leaves and seeds of control plants.

[Study of HRas1 minisatellite frequencies in children with thyroid papillary cancer]. / Izuchenie chastot minisatellita HRas1 sredi detei s papilliarnym rakom shchitovidnoi zhelezy.

The "rare" alleles of HRas1 gene minisatellite are well-known factor of predisposition to many kinds of cancer. We have studied HRas1 minisatellite frequencies among patients with papillary thyroid cancer which is related to consequences of Chernobyl accident. The HRas1 minisatellite was analysed in 32 patients who suffered from papillary carcinoma and underwent operation in 1996-2001 and in 75 Belorussian residents. Of 64 HRas1 alleles revealed in patients 14 were defined as "rare" (21.9%); in the control group we have detected 17 "rare" alleles (11.3%) of the examined 150 alleles. The higher frequency of "rare" HRas1 minisatellite alleles in patient group was statistically significant (p < 0.01). We can suppose that the "rare" alleles of HRas1 minisatellite are associated with increased risk of papillary thyroid cancer formation in children and adolescents after Chernobyl accident.

[ret/PtC1 and ret/PTC3r1 rearrangement in thyroid cancer cells, arising in residents of Belorus in the period after the accident at the Chernobyl nuclear power plant]. / Perestroiki ret/PTC1 i ret/PTC3r1 v kletkakh raka shchitovidnoi zhelezy, voznikshie u zhitelei Belorussii v period posle avarii na ChAES.

After the accident at the Chernobyl nuclear power plant, a considerable increase in the incidence of thyroid cancer among children in Belarus was observed. In the present study, the frequency of the c-ret protooncogene rearrangements in samples of thyroid carcinomas resected and diagnosed in 1998 from individuals in Belarus was investigated. The ret/PTC1 oncogene was detected in 19% of the samples, and the ret/PTC3r1 oncogene, in 14%. The number of ret/PTC1 rearrangements observed in tumor cells from the patients whose age at the time of the accident was from 1 to 10 years, was greater compared to those whose age at the time was from 10 to 20 years, irrespective of the year of surgery (1996 or 1998). The majority of the patients with ret/PTC3r1 rearrangements lived in Gomel oblast, which was contaminated by the Chernobyl meltdown.