Plasminogen activator and collagenase production by cultured capillary endothelial cells

Cultured bovine capillary endothelial (BCE) cells produce low levels of collagenolytic activity and significant amounts of the serine protease plasminogen activator (PA). When grown in the presence of nanomolar quantities of the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA), BCE cells produced 5-15 times more collagenolytic activity and 2-10 times more PA than untreated cells. The enhanced production of these enzymes was dependent on the dose of TPA used, with maximal response at 10(-7) to 10(-8) M. Phorbol didecanoate (PDD), an analog of TPA which is an active tumor promoter, also increased protease production. 4-O-methyl-TPA and 4α-PDD, two analogs of TPA which are inactive as tumor promoters, had no effect on protease production. Increased PA and collagenase activities were detected within 7.5 and 19 h, respectively, after the addition of TPA. The TPA-stimulated BCE cells synthesized a urokinase-type PA and a typical vertebrate collagenase. BCE cells were compared with bovine aortic endothelial (BAE) cells and bovine embryonic skin (BES) fibroblasts with respect to their production of protease in response to TPA. Under normal growth conditions, low levels of collagenolyic activity were detected in the culture fluids from BCE, BAE, and BES cells. BCE cells produced 5-13 times the basal levels of collagenolytic activity in response to TPA, whereas BAE cells and BES fibroblasts showed a minimal response to TPA. Both BCE and BAE cells exhibited relatively high basal levels of PA, the production of which was stimulated approximately threefold by the addition of TPA. The observation that BCE cells and not BAE cells produced high levels of both PA and collagenase activities in response to TPA demonstrates a significant difference between these two types of endothelial cells and suggests that the enhanced detectable activities are a property unique to bovine capillary and microvessel and endothelial cells.     

Dehydrins associated with the development of frost resistance of Asian white birch

Seasonal changes in the content of dehydrins in Asian white birch (Betula platyphylla Sukacz.) growing under extreme cold conditions of Eastern Siberia (Central Yakutia) were studied for the first time by SDS-PAGE and immunoblotting. Several polypeptides, including putative storage proteins, which content was higher in winter than in other periods, were observed. Intraspecies polymorphism of dehydrins was detected during plant dormancy. The two groups of dehydrins were found: dehydrins with mol wts of 56-73 kD, which were present year-round, and dehydrins with mol wts of 15–21 kD, evidently related to the development of frost resistance because they were absent in summer but present in large amounts in winter. Under low winter temperatures, the highest level of dehydrins coincided with the lowest content of water in buds, which was accompanied by increased plant frost resistance to the highest values.     

Human innate immunity under the conditions of five-day dry immersion

The system of congenital immunity was studied in 12 apparently healthy men 18 to 26 years of age subjected to five-day dry immersion without the use of countermeasures. Peripheral blood was analyzed for monocytes, granulocytes, and lymphocytes expressing the TLR²⁺, TLR⁴⁺, TLR⁶⁺, CD11b⁺, CD¹⁴⁺, CD¹⁶⁺, CD¹⁸⁺, CD²⁴⁺, CD³⁶⁺, CD⁵⁴⁺, CD⁵⁶⁺, and CD²⁰⁶⁺ receptors. Expression of the early activation marker CD69 on natural killer cells was studied in unstimulated and interleukin-2-activated mononuclear cell cultures. The negative shifts in the congenital immunity system in some volunteers at the end of immersion and during recovery can be regarded as warnings about the depletion of the system’s reserves and the increase of the risk of infectious diseases, such as those caused by normal microflora, which typically does not provoke pathological reactions in the host.     

Immunological aspects of a space flight to Mars

The effects on the immune system of a 520-day isolation in a confined environment, simulating some conditions of a manned space flight to Mars, have been studied. A set of signs of adaptational reorganization, including quantitative and functional changes in innate and adaptive immunity, have been recorded. The most significant ones include the changes in the system of Toll-like receptors (TLRs) manifested as a decrease in the content of circulating monocytes and granulocytes expressing TLR2, TLR4, and TLR6; a decrease in the functional capacity of cellular factors of natural cytotoxicity or natural killer cells (NK cells); an increased ability of T cells and B cells to express on their surface the CD69 early activation marker; and an increase in phytohaemagglutinin (PHA)-induced secretion by cytokines in peripheral blood mononuclear cells. Intense mobilization of adaptive immunity and qualitative changes of its functions demonstrates the adaptive adjustment of the body in response to the combined effect of unfavorable factors to preserve immune homeostasis.     

IR and Raman spectroscopy in the study of carotenoids of <Emphasis Type="Italic">Cladophora rivularis</Emphasis> algae

Using Raman and infrared spectroscopy it has been found that during the normal life of algae (pH changes from 8.0 to 9.0) the content of carotenoids increases and the molecules change their conformation: the contribution of–C=C–bonds of the polyene chain of a carotenoid molecule (Raman spectroscopy) is reduced and the contribution of methyl groups (～2940 cm^–1) and aromatic C–H-plane deformation vibrations (band at 1050 cm^–1) of carotenoid molecules (infrared spectroscopy) decreases as well. It is the opinion of the authors that a change in the extracellular pH within the normal range has no influence on the content of chlorophyll a and b, but tends to increase the content and alter the conformation or structure of carotenoid molecules.     

Study of the filiform gonads of walleye pollock <Emphasis Type="Italic">Theragra chalcogramma</Emphasis> inhabiting the Sea of Okhotsk and the Bering Sea

The histological study of the adult specimens of walleye pollock Theragra chalcogramma carrying filamentous gonads evidenced that this group comprised males, females, and sterile fish. The specimens carrying the filamentous gonads have been found mostly in the elder age groups; no maturing of the oocytes or sperm cells has been registered. The frequency of occurrence of such specimens was relatively low: 0.07–0.13% in the Sea of Okhotsk and up to 0.25% in the Bering Sea. We conclude that these specimens have nearly no effect on the reproductive success of this species.     

Polymer chromosome models and Monte Carlo simulations of radiation breaking DNA

MOTIVATION: Chromatin breakage by ionizing radiation is relevant to studies of carcinogenesis, tumor radiotherapy, biodosimetry and molecular biology. This article focuses on computer analysis of chromosome irradiation in mammlian cells. METHODS: Polymer physics and Monte Carlo numerical methods are used to develop a coarse-grained computational approach. Chromatin is modeled as a random walk on a cubic lattice, and the radiation tracks hitting the chromatin are modeled as straight lines hitting lattice sites. Each track can make a cluster of DSBs on a chromosome. RESULTS: The results obtained replace conjectured DNA fragment-size distribution functions in the recently developed RLC formalism by more mechanistically motivated distributions. The discrete lattice algorithm reproduces features of current radiation experiments relevant to chromatin on large scales. It approximates the continuous formalism and experimental data with adequate precision. It was also found that assuming either fixed chromatin with correlations among different clusters of DSBs or moving chromatin with no such correlations gives virtually identical numerical predictions.     

Mapping of Changes in EEG Spectrum Power during a Session of Biofeedback Training of the β1 Rhythm

Changes in EEG spectrum power from 19 electrode sites were studied in 19 children with attention disorders during one session of EEG–biofeedback (EEG–BFB). EEG–BFB was aimed at increasing the relative power of the ₁ rhythm (15–18 Hz) in sites Fz–C ₃ with a bipolar electrode assembly. Comparison of the EEG spectrum powers at relaxation versus training periods in one BFB session revealed significant changes in the left parasagittal frontoparietal area (F ₃, Fz, C ₃, C ₄, P ₃).