Frequency of stable chromosomal aberrations determined by FISH in 49 Chernobyl nuclear accident liquidators exposed to various doses of radiation

FISH technique was tested on the 49 liquidators of the Chernobyl Accident. Groups were formed according to average group exposure doses and/or individual ones determined by the method of EPR. The essential variability of spontaneous and irradiation-induced frequencies of reciprocal translocations was observed. In groups with the lowest EPR-doses (below 25 cGy) the average cytogenetic dose was considerably higher then doses determined by EPR-method. The best coincidences between average in-group EPR- and FISH-doses were in the group with 25-50 cGy doses for "acute irradiation" model and in the group with 50-100 cGy and higher for "chronic irradiation" model.     

Response of motor units of the abdominal musculus rectus to afferent input in the course of the long-lasting activity in rats

In rats, in the course of a long-lasting m. rectus abdominis motor units activity combined with repetitive afferent stimulation of the ischiadic nerve, the units' firing rate decreased. The dependence of the motor units response to afferent stimulation on the background firing rate was preserved during the long-lasting activity in spite of changes in the background firing rate.     

Irregular zonal distribution of actinin and tropomyosin in the rat kidney

The cortical actinin contents was found to be higher in the inner medulla of the rat kidney. Tropomyosin was distributed differently: it is lower in the cortex than in outer or inner medulla. The processes controlled by these proteins seem to be important for the vasopressin renal effects, and the irregular distribution of these proteins reflects participation of different renal areas in facultative water reabsorption.     

Quantitative evaluation of 90Sr, 137Cs, 239Pu, 241Am transfer from polluted soil to gastric and intestine juice of cows

Quantitative parameters of 90Sr, 137Cs, 239Pu and 241Am transfer from solid phase of soil to gastric, intestine juice of cows as well as to imitating solutions have been estimated on the base of results of laboratory incubation experiments. A prevailing role of enzyme complex and microflora of gastrointestinal tract in radionuclides transfer from solid phase of soil to solution has been shown.     

Effect of initial (spontaneous) arterial pressure on systemic hemodynamic orthostatic responses

In anesthetized rats, a reverse linear correlation of arterial pressure (AP) shifts was found within the range of initial AP over 95 mm Hg under the head-up tilts at 30 and 45 degrees. Within the range beneath 95 mm Hg this correlation was transformed into the direct one. Under 60 degrees tilt such correlation only occurred within the range beneath 95 mm Hg. The direction and degree of the arterial system responsiveness seems to depend on the tilt value as well as on the range of the initial AP.     

Analysis of DNA status in bone marrow cells of mice internally irradiated with 90Sr

The response of bone marrow cells of CBA mice injected with 22.2, 222 and 592 kBq/animal to additional gamma-irradiation (3 Gy) for testing purposes was evaluated using SCG (Comet assay). A decrease in induction of DNA damage right after additional gamma-irradiation was determined. It correlated with bone marrow cell quantity and the tail length before additional gamma-irradiation. The results support the suggestion about the activation of DNA repair in bone marrow cells under exposure to 90Sr in vivo.     

Effect of pineal peptide on parameters of the biological age and life span in mice

Female CBA mice were injected with s.c. synthetic tetrapeptide Epithalon from a 6-month age until death. The drug failed to affect the body weight or food consumption, physical activity or behavioural parameters. However, it slowed down the age-related switching off of the estrus function, decreased body temperature, decelerated free redical processes, prolonged the mice life span with an accompanying drop in spontaneous tumour incidence.     

Specific features of the HIV infection epidemic in Moscow

Retrospective analysis of the epidemic of HIV infection in Moscow allowed to mark out two periods: the first--from 1987 to 1993 and the second one--from 1994 to 2000. The characteristic feature of the first period of the epidemic was the sexual transmission of the agent mainly among homosexuals; the most affected group were persons aged 20-39 years and the number of AIDS patient decreased with a simultaneous growth in lethality. During the second stage of the HIV infection epidemic changes in the prevailing transmission routes of the agent occurred: injection drug addicts took the leading role. Changes in the ratio of HIV-infected men and women took place along with active involvement of persons aged 13-18 years into the epidemic process. The established changes in the epidemiological situation require corrections in the strategy and tactics of epidemic control and prophylactic measures.     

Molecular biological mechanisms of the variability of Helicobacter pylori

Nowadays notions on the variability of Helicobacter pylori are reviewed. Genetic polymorphism of H. pylori is manifested by variability of gene properties and their order in different strains due to recombinations occurring in these bacteria much more frequently than in other bacterial species. H. pylori belongs to those bacteria which are capable of natural transformation. Transformation is very often observed both in vitro and in vivo. A significant role in the variability of H. pylori is played by transposons and specific nature of mutagenesis. The author emphasizes that differentiation between the roles played by recombinations and mutations in the variability of H. pylori is difficult. Special attention is paid to the resistance of H. pylori strains to chemotherapeutic drugs and to the mechanisms of its development.     

Hepatitis A in Estonia (1990-1999)

During recent 10 years (1990-1999) essential changes occurred the epidemiology of viral hepatitis A (VHA) in Estonia: simultaneously with a decreased level of morbidity (morbidity rate per 100,000 of the population was 78.4 in 1990 and 7.7 in 1996, or 1,241 and 112 cases, respectively), a shift in the age structure of patients from children of preschool age to older age groups took place. Everyday contacts were the main established route of VHA transmission in recent years, but in more than 80% of cases the risk factors of the virus transmission remained obscure. During the regional outbreak of VHA in North Estonia in 1998 (937 out of 989 cases registered in the country) a rise in morbidity was observed among young people aged 15-29 years, when a wide spread of parenteral viral hepatitides B and C and drug addiction were registered in this region. During this outbreak VHA was transmitted mainly through everyday contacts. Still the considerable prevalence of injection drug users who practiced the group use of syringes and needles and took drugs from common containers, a sufficiently high level of the mixed forms of the disease (more than 18% of all registered cases of VHA), detected for the first time, make it possible to suggest that the parenteral transmission route could appear among persons belonging to the above mentioned group. Vaccination is regarded as the most effective measure for the prophylaxis of VHA.