Biomechanical rationale of coronary artery bypass grafting of multivessel disease

The biomechanical model of human coronary arteries was modified for improving the quality of diagnosis and surgical treatment for coronary heart disease. The problem of hemodynamics in the left coronary artery with multivessel bed disease – 45% stenosis of the anterior descending branch and 75% stenosis of the circumflex branch – was particularly considered. Numerical simulation of the coronary arterial bypass of the main trunk was carried out to estimate the functional condition of the coronary arteries after restoring myocardial blood supply by surgery.     

Antigenic structure of Salmonella L forms studied by an immunoferritin method

The antigenic structure of the L-forms of salmonellae (S. typhimurium and S. typhi) in comparison with that of the initial bacterial cultures and revertant cultures was studied with the use of the immunoferritin method. The L-forms of salmonellae were found to retain an insignificant amount of O-antigen, as well as to have K-antigen on the surface of the cytoplasmic membrane, but in a lesser amount than the initial strains. In the cultures reverting from the L-forms of S. typhimurium and S. typhi the quantitative and qualitative characteristics of O- and K-antigens were completely restored.     

Bacteriolytic enzymes produced by actinomycetes. II. Biosynthesis and areas of practical application

The data on physiological conditions of the bacteriolytic enzyme formulation of actinomycetes, the population structure of producing cultures, the search of producers of enzymes able to hydrolyze the peptidoglycan of cellular walls of bacteria are reviewed. The fields of application of lytic enzymes in fundamental and applied microbiological investigations are pointed out. These enzymes are of considerable interest as potentially useful chemotherapeutics and food preservatives. They may be successfully used in biochemical and genetic investigation, in the study of peptidoglycan structure. The ability of bacteriolytic enzymes to cause the lysis of microorganisms resistant to the lysozyme action is of special importance. The application of these enzymes allows to work out gentle methods of lysis of bacterial cells used in various fields of microbiology.     

A new chromosomal sex-determining mechanism inMicrotus arvalis pallas

The karyotype in the rodentMicrotus arvalis comprises 21 autosome pairs and two heterosome pairs of the X₁X₂Y₁Y₂/X₁X₁X₂X₂ type. The occurrence of multiple sex chromosomes is thought to be due to a translocation of one arm of a metacentric autosome to the Y chromosome. This translocation would result in an additional acrocentric sex chromosome confined to the(heterogametic) male line, i.e., a Y₂. The original metacentric chromosome thereby turns into an X₂. Because of the translocation mentioned, a trivalent figure of the Y₁Y₂X₂ type occurs in the first meiotic metaphase in the male.     

The cytotoxic activity of natural killer cells exposed to the joint and separate actions on the body of 239Pu, hexachlorobutadiene and tributyl phosphate

Wistar rats were subjected to a single exposure to 239Pu nitrate through inhalation with the subsequent procedure of imitation of inhalation or without it (the amount of 239Pu deposited in the lungs in 24 hr was 8.9 +/- 1.9 kBq/lung) and inhalation of hexachlorobutadiene and tributyl phosphate within one month in a combination with the radionuclide or without it. There was a 1.5-fold increase, above additive, in the harmful effect of 239Pu and chemical agents on the function of natural killers as observed 15--30 days after the combined exposure as compared to individual inhalation. On days 120 to 240 cell cytotoxic activity in rats of all groups was normalized to reach or to exceed the intact control.     

Recombinant adenoviruses with large deletions generated by Cre-mediated excision exhibit different biological properties compared with first-generation vectors in vitro and in vivo.

In vivo gene transfer of recombinant E1-deficient adenoviruses results in early and late viral gene expression that elicits a host immune response, limiting the duration of transgene expression and the use of adenoviruses for gene therapy. The prokaryotic Cre-lox P recombination system was adapted to generate recombinant adenoviruses with extended deletions in the viral genome (referred to here as deleted viruses) in order to minimize expression of immunogenic and/or cytotoxic viral proteins. As an example, an adenovirus with a 25-kb deletion that lacked E1, E2, E3, and late gene expression with viral titers similar to those achieved with first-generation vectors and less than 0.5% contamination with E1-deficient virus was produced. Gene transfer was similar in HeLa cells, mouse hepatoma cells, and primary mouse hepatocytes in vitro and in vivo as determined by measuring reporter gene expression and DNA transfer. However, transgene expression and deleted viral DNA concentrations were not stable and declined to undetectable levels much more rapidly than those found for first-generation vectors. Intravenous administration of deleted vectors in mice resulted in no hepatocellular injury relative to that seen with first-generation vectors. The mechanism for stability of first-generation adenovirus vectors (E1a deleted) appeared to be linked in part to their ability to replicate in transduced cells in vivo and in vitro. Furthermore, the deleted vectors were stabilized in the presence of undeleted first-generation adenovirus vectors. These results have important consequences for the development of these and other nonintegrating vectors for gene therapy.     

Electron microscopic study of the interaction of Yersinia pseudotuberculosis with macrophages and HeLa cells

The comparative electron-microscopic study of early stages of the interaction of Y. pseudotuberculosis virulent strain (No. 282) with "professional" (macrophages) and "nonprofessional" (HeLa cells) phagocytes has been carried out. The character of the intimate mechanism of this interaction has been found to be essentially different. The common feature for both systems is the adsorption of bacteria and their penetration into cells due to phagocytosis. But the subsequent fate of Y. pseudotuberculosis is different. In HeLa cells they are isolated from the cytoplasm by multilayer membrane structures, thus remaining morphologically intact. In macrophages the destruction of the microbe in phagolysosomes occurs.     

Cloning of murine B- and T-lymphocytes in vitro after the long-term action of tritium oxide

The cloning method was used to study the content of B- and T-lymphocyte committed precursors in central and peripheral organs of the immune system of mice at different times after long-term exposure to tritium oxide (a cumulative dose of approximately 9 Gy). It was shown that recovery of the colony-forming ability of the committed lymphocyte precursors was different in central and peripheral lymphoid organs; the dynamics and degree of restoration of the pools of B--(CFU--LB) and T--(CFU--LT) lymphocyte precursors were different.     

Electron microscopic study of the interrelation of the L forms of beta-hemolytic Streptococcus group A with mouse peritoneal macrophages

Interrelations between the L-forms of group A beta-hemolytic streptococci and mouse peritoneal macrophages have been studied by electron microscopy. The macrophages have been shown to actively phagocytize L-form cells in great amounts. Most of the phagocytized L-forms are destroyed and become nonviable, but a few of them survive as elementary bodies within 48 hours.