Equivalent electrical network of the DNA molecule

The variation of current density with bias or temperature is examined for DNA molecules of different configuration. To this end, the DNA molecule is represented as an equivalent electrical network whose behavior is then simulated with PSPICE. The results are found to be in close agreement with ones obtained within a physical model. It is established that the electrical response of a DNA molecule to an applied electric field depends on the boundary conditions and the potential profile along the molecule. This finding should contribute to the creation of a complete library of DNA-molecule configurations with prescribed electrical properties.     

Modeling, histological study and pathogenetic aspects of experimental traumatic osteomyelitis

The tibial diaphysis osteotomy with limited separation of periosteum on the ends of the fragments with subsequent local infection by Staphylococcus aureus culture was conducted. In 90% of observations chronic inflammation was revealed in affected bones while morphological investigation conduction. An acute traumatic disorders of intraosseous blood circulation (the bone infarction) and local staphylococcal infection play the main role in the traumatic osteomyelitis pathogenesis.     

Mutagenic and antimutagenic activities of human whole blood, plasma and albumin

The seeds of Crepis capillaris were used to examine the mutagenic und antimutagenic properties of human whole blood, plasma, serum albumin and gamma-globulin by recording chromosomal and chromatid aberrations. The antimutagenic activity was determined by preliminary, simultaneous, and subsequent biosubstrate treatments of the seeds. The whole and twice-diluted blood, as well as plasma, induced aberrations exceeding the level of self-arbitrary mutagenesis by 3.7-5.3 and 2.6-3.1 times, respectively. When the blood was diluted to its 20% concentration, the antimutagenic efficiency of biological fluids was recorded. Human serum albumin and gamma-globulin were found to have an antimutagenic effect. In the dilutions having no antimutagenic effect, blood, plasma, and albumin showed their ability to be effectively decrease the level of induced aberrations.     

Pathology of AIDS in children

AIDS in children is a multisystem disease. The various infections, degenerative, proliferative and vascular lesions can be classified into three categories based on the known, presumed or undetermined pathogenesis. The primary lesions are due to HIV infection. The associated lesions are related to direct or indirect sequelae of HIV infection or its treatment. The third category is of lesions of undetermined pathogenesis. The pediatric pathologist plays an important role in the study and management of AIDS by demonstrating new pathologic lesions, by making the etiologic diagnosis of infection in children with AIDS, and by providing clinicopathologic correlation which leads to better understanding of the disease process and its natural history. Diagnosis of neoplastic disorders is also made by the pathologist. There is a dearth of systematic pathologic study of AIDS in children in developing countries. Although no basic differences between pathologic lesions in pediatric AIDS in Western countries, and in developing countries is expected, such a study would lead to better understanding and better management of the disorder as it affects children from the developing countries.     

Variability in the proliferative responsiveness of cultured human vascular smooth muscle cells to alpha-thrombin

alpha-Thrombin, a key enzyme of the coagulation cascade, is also a potent mitogen for many cell types. In the present study, the responsiveness to alpha-thrombin of cultured human vascular smooth muscle cells (HVSMC) derived from either vein or normal and atherosclerotic arteries was investigated. All HVSMC populations examined responded mitogenically to alpha-thrombin. However, the extent of this response varied between different cell populations. No significant differences were observed between HVSMC derived from vein versus artery or atherosclerotic versus normal tissues. The responsiveness of a specific HVSMC culture to alpha-thrombin was not affected by cell density and remained constant over several passages. Unlike platelet-derived growth factor BB (PDGF-BB), alpha-thrombin did not exhibit any significant chemotactic effects on HVSMC or induce their anchorage independent growth in semi-solid medium. The hypothesis that the observed variability in HVSMC responsiveness to alpha-thrombin is due to the heterogeneity of cultured HVSMC is raised and discussed.