Effect of initial (spontaneous) arterial pressure on systemic hemodynamic orthostatic responses

In anesthetized rats, a reverse linear correlation of arterial pressure (AP) shifts was found within the range of initial AP over 95 mm Hg under the head-up tilts at 30 and 45 degrees. Within the range beneath 95 mm Hg this correlation was transformed into the direct one. Under 60 degrees tilt such correlation only occurred within the range beneath 95 mm Hg. The direction and degree of the arterial system responsiveness seems to depend on the tilt value as well as on the range of the initial AP.     

Store-operated cationic channels in human myeloid leukaemia K562 cells

Using the whole-cell patch clamp technique, single channels operated by intracellular Ca(2+)-store depletion were first revealed in human myeloid leukaemia cells K562. A single store-operated channel could be detected in divalent-free extracellular solutions with Na+ as a permeant ion, and intracellular solutions with strong Ca(2+)-helating agent with some delay after whole-cell formation. Addition of inositol-1,4,5-triphosphate to the pipette solution resulted in a significant decrease of this latency. These channels had a conductance of 29 pS, and were inhibited by low concentration of external Ca2+. Our results enable us to assume that the revealed channels are calcium release-activated calcium channels, operated by Ca2+ depletion of endoplasmic reticulum.     

Calculation of the morbid risk in genetic-epidemiologic studies of age-dependent diseases

Distributions of age at onset are widely used in the genetic epidemiology of age-dependent diseases. Examples are estimation of recurrent risks in genetic counselling and testing genetic hypotheses in segregation and linkage analyses. In this study, morbidity parameters are defined, including age-specific morbidity rates, morbidity net risk (incidence), and cumulative incidence (population risk, an integrated measure of population susceptibility to the disease at the moment of the study). Age-specific morbidity risks are calculated from the respective morbidity rates, which are analogous to mortality rates used in demography. Population data typically used for calculation of morbidity rates are discussed. Methods of calculation of morbidity rates based on the data of single and interval epidemiological studies are described. Methods for calculating standard errors of these parameters, estimating their statistical reliability, and testing statistical hypotheses are discussed.     

Comparative Biogeography of Grasshoppers (Orthoptera: Acrididae) in North America and Siberia: Applications to the Conservation of Biodiversity

The objective of this study was to apply knowledge of holarctic grasshopper biogeography in representative, temperate ecosystems (Russia, South Siberia, Sayans region; 685,000km² and USA, Wyoming; 272,000km²) to develop a comparative basis for understanding and conserving insect biodiversity. Maps of species distributions and vegetation zones were digitized, and a Geographic Information System was used to identify habitats with the greatest biodiversity and to characterize this diversity as a function of selected attributes. With respect to subfamilies, the greatest differences were in cold, mesic zones, where gomphocerines and melanoplines were dominant in Sayans and Wyoming, respectively. In terms of mobility, the Sayans has more flightless species and individuals, with the taiga supporting the greatest frequency of flightless acridids in both countries. With regard to feeding types, the diversity and richness of graminivores and forbivores were similar in the two regions, but mixed feeders were much more frequent in Wyoming. In the Sayans and Wyoming, pest species were most common in boreal and prairie zones, respectively. Ecoregions with a high diversity of pests also supported a high diversity of rare species. Shrub and desert zones supported many rare species in both countries. Thus, in terms of conservation, the Sayans' acridofauna appears to be at greater risk in terms of ecological vulnerability; acridid biodiversity is dispersed among habitats, with high frequencies of flightless and oligophagous species. The acridofauna of Wyoming could be conserved in fewer habitats than in the Sayans, but these habitats are subject to considerable human disturbance.     

Dependence of arterial pressure and cardiac output on initial (regulated) arterial tone during beta-adrenoreceptor stimulation in rats

A significant decrease of arterial pressure in response to isoproterenol occurred in anaesthetised rats with the initial pressure 101-130 mm Hg. Elevation of the initial pressure up to 131-180 mm Hg led to a significant attenuation of the depressor effect. The correlation analysis revealed transformation of direct correlation into inverse one between the depressor responses to isoproterenol and the degree of elevation of the initial arterial tone, as well as lack of such a dependence in the cardiac output shifts.     

Distribution of the spider mite Tetranychus urticae Koch (Acarina,Tetranychidae) over the leaves of different cucumber cultivars

Distribution of spider mites over cucumber leaves is determined by the topical trophic specialization of the pest manifested in preference for the central leaf zone. After artificial infestation of leaves with female mites, the modified aggregated distribution of the pest depended on the number of mites on the leaf, the morpho-physiological state and stage of development of the leaf and the whole plant, and the cucumber cultivar.     

Microarray analysis of Bacillus cereus group virulence factors

Bacillus cereus, B. thuringiensis and B. anthracis are closely related medically and economically important bacterial species that belong to the B. cereus group. Members of the B. cereus group carry genes encoding several important virulence factors, including enterotoxins, phospholipases and exotoxins. Since it is difficult to differentiate among B. cereus group members, and because Bacillus virulence factors are very important for pathogenesis, we explored the use of microarray-based detection of virulence factor genes as a tool for strain identification and for determining virulence. Our method requires an initial multiplex PCR amplification step, followed by identification of the PCR amplicons by hybridization to an oligonucleotide microarray containing genes for all three types of Bacillus virulence factors including B. anthracis virulence factors. The DNA chip described here contains 21 identical arrays used for analysis of seven samples in triplicates. Using the arrays, we found that virulence factors are present in several combinations in the strains analyzed. This work also demonstrates the potential of oligonucleotide microarrays for medical, food safety and biodefense analysis of microbial pathogens.