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The frequency of nonhemagglutinating (h-) mutants was determined in hemagglutinating (HA) clones of echovirus 11. The HA clones were derived from the prototype strain Gregory and a clinical isolate of echovirus 11. The h- mutants were found at a constant frequency of 3.0 x 10(-5) (mean value) in the HA clones derived from both strains. Since the conditions of the population equilibrium of HA clones and neutrality of the mutation were satisfied, it was proposed that the observed frequency of h- mutants occurred as a result of a point mutation. The frequency of h+ revertants at the second passage of h- mutant clone was 9.1 x 10(-5). Hence the frequency of reversion suggests that the number of potential sites of back mutation was restricted.

The results of epidemiological studies of risk factors for the development of dystrophic diseases of the vulva (DDV) in women of reproductive and perimenopausal age are presented. Authors executed the testing of DDV patients according to specially developed questions of the questionnaire, aimed at the obtaining of the most complete information about the lifestyle of patients, social and medical factors, possibly contributing to the occurrence and formation of DDV. Also, the authors performed an examination of patients for the most common sexually transmitted infections (STIs), and urogenital infections in order to clarify the infectious factor in the genesis of dystrophy of the vulva. Direct and indirect factors that contribute to the formation of dystrophic diseases of the vulva in women are established to be as follows: perimenopausal age; endocrine diseases; emotional stress of a social character; more than 3 pregnancies in anamnesis; presence of STIs (herpes simplex virus, cytomegalovirus) and inflammatory diseases of the pelvic organs; presence of Candida fungi, Ureaplasma urealyticum bacteria, human papillomavirus - HPV 16/18, HPV 31/33 and some other infections on the background of DDV; lack of information about the disease; discharge from the genital tract; lack of treatment-effect; inappropriate treatment. The identified factors should be taken into account in the development of therapeutic and preventive measures in relation to DDV in women.

The composition, apolipoprotein structure and lipoprotein binding to the LDL receptor were studied for very-low-density (VLDL) and low-density lipoprotein (LDL) particles isolated from subjects with apoE phenotype E3/3 (E3), E2/2 or E2/3 (E2+) and E3/4 or E4/4 (E4+) and a wide range of plasma triglyceride (TG) contents. The data combined for all three phenotype groups can be summarized as follows. (i) A decrease in accessibility of VLDL tryptophan residues to I- anions with a decrease in tryptophan surface density, concomitant with an increase in VLDL dimensions, reflects the increased efficiency of protein-protein interactions. (ii) A gradual increase in the quenching constant for LDL apoB fluorescence with an increase in TG/cholesterol (Chol) ratio reflects the 'freezing' effect of Chol molecules on apoB dynamics. (iii) Different mechanisms specific for a particular lipoprotein from E3/3 or E2/3 subjects are responsible for apoE-mediated VLDL binding and apoB-mediated LDL binding to the LDL receptor in a solid-phase binding assay. (iv) The 'spacing' effect of apoC-III molecules on apoE-mediated VLDL binding results in a decrease in the number of binding sites. (v) The maximum of the dependence of the LDL binding affinity constant on relative tryptophan density corresponds to LDL intermediate size. VLDL particles from hypertriglyceridemic E2/3 heterozygotic individuals had remnant-like properties (increased cholesterol, apoE and decreased apoC-III content) while their binding efficiency was unchanged. Based on the affinity constant value and LDL-Chol content, increased competition between VLDL and LDL for the binding to the LDL receptor upon increase in plasma TG is suggested, and LDL from hypertriglyceridemic E3/3 homozygotic individuals is the most efficient competitor.

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