No abstract

This study was initiated to determine the relationship between the fertilizing potential of spermatozoa and abnormalities in the compact packing of their chromatin which occurs in the final stage of male germ cell differentiation. Chromatin packing involves disulphide bridge covalent cross-linking. The degree of packing was determined from the accessibility of DNA to a fluorescent dye, ethidium bromide, following detergent treatment of the spermatozoa. The amount of dye bound was determined by flow cytometry in the presence or absence of heparin, a polyanion which removes only non-disulphide bridge-linked proteins. The results of a number of different sperm samples were compared with their results following in-vitro fertilization, and a relationship between disordered sperm chromatin packing and rates of embryo cleavage was observed. This study suggests that abnormal chromatin packing in spermatozoa may contribute to male fertility.

BackgroundOne of the causes of Parkinson's disease is mutations in the PARK2 gene. Deletions and duplications of single exons or exon groups account for a large proportion of the gene mutations. Direct detection of these mutations can be used for the diagnosis of Parkinson's disease.MethodsTo detect these mutations, we developed an effective technique based on the real-time TaqMan PCR system, which allows us to evaluate the copynumbers of the PARK2 gene exons by comparing the intensity of the amplification signals from some exon of this gene with that of the β-globin gene (the internal control).ResultsWe analyzed rearrangements in exons 1–12 of the PARK2 gene in 64 patients from Russia with early-onset Parkinson's disease. The frequency of these mutations in our patients was 14%.ConclusionWe have developed a simple, accurate, and reproducible method applicable to the rapid detection of exon rearrangements in the PARK2 gene. It is suitable for the analysis of large patient groups, and it may become the basis for a diagnostic test.

Despite the great interest of the scientific community in the behavior of the human body after contact with the new coronavirus severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), long‐term (more than 6 months) monitoring of the immunological status of patients with coronavirus disease 2019 (COVID‐19) having varying severity degrees and of the people with a low SARS‐CoV‐2 viral load is practically absent. The aim of this study is a 9‐month monitoring of SARS‐CoV‐2 infection immune response development and extinction using quantitative assessment of IgA and IgG levels in the blood of healthy donors living in the context of the coronavirus pandemic and of the patients who have undergone COVID‐19. The project involved 180 volunteers, of whom 51 persons (28.33%) fell ill with COVID‐19 during the observation period. All people who underwent COVID‐19 developed a stable humoral immune response but their individual immune status had a number of features. Approximately 39.22% (20 of 51 people) of project participants diagnosed with COVID‐19 showed an unusual change in plasma anti‐SARS‐CoV‐2 IgA levels. Relatively high levels of IgA (ratio ~ 3) after recovery persisted for a long time (more than 6 months). In one‐third (17 of 51 people) of patients with COVID‐19, the IgA level exceeded the IgG level. IgA antibodies appeared earlier and showed a stronger and more robust response to the SARS‐CoV‐2 virus than IgG. Increased levels of anti‐SARS‐CoV‐2 IgA (ratio from 0.8 to 2.36) throughout the observation period were recorded in 28 of 180 project participants (15.56%) of whom only one person fell ill with COVID‐19.

The paper considers a method for solving nonlinear ill-posed problems with monotone operators. The approach combines the Lavrentiev method, the fixedpoint method, and the balancing principle for selection of the regularization parameter. The method’s optimality has been proved for some set of smooth solutions. A test example proves the efficiency of the proposed method.