Use of non-radioactive biotin-labelled probes for detecting hepatitis A virus]

The biotin-labeled DNA probes were constructed on the basis of the hybrid bacteriophage M13nip 9 single-stranded DNA containing the fragments of the hepatitis A viral cDNA. The probes were biotin treated by chemical modification of the DNA by the peraminating reagent or photochemically. The labeled DNA probes were used in molecular hybridization experiments with the nuclear acids fixed on the nitrocellulose filters. The biotin treated DNA was determined by the avidin-gold colloid conjugate with the subsequent physical silver amplification or by the streptavidin-alkaline phosphatase conjugate. The sensitivity of both probes was identical and permitted the determination of 5 x 10(-11)-5 x 10(-12) g of the control DNA and 10(-9) g of the hepatitis A virus. The developed test systems were used for detection of the viral RNA in blood from patients.     

Dimensions and alveolar surface of the ineralveolar septa of the rat lung]

The dimensions of the alveolar surface of interalveolar septa were studied in albino rats. The mean thickness of certain septa range from 3,1 to 6,2 mu, the mean thickness of the septa in different individuals being factually the same. A part of the alveolar surface of the septa represents the air-haematic barrier which occupies 51-64% of the total alveolar surface in different rats. The mean values of all the parameters in the animals studied are very close. It shows that the interalveolar septa are standard structures in their organization and dimensions both in the same animal and in different animals of the same species.     

Human heart muscle proteins: two-dimensional electrophoretic analysis in embryos

Human myocardium proteins synthesized in the course of heart muscle development have been analyzed by two-dimensional electrophoresis. The quantitative change was found in representation of the main retractable proteins in the course of the heart muscle formation (the light myosin chains, tropomyosin, etc.). Four polymorphous variants of myocardium proteins were found, one of which is, possibly connected with the defect in heart development.     

<Emphasis Type="Italic">P</Emphasis>300-based brain-computer interface: The effect of the stimulus position in a stimulus train

The most popular type of brain-computer interfaces (BCIs) are based on the detection of the P300 wave of the evoked potentials appearing in response to a stimulus chosen by the subject. In order to increase the speed of operation of these BCIs, it is possible to decrease the number of repeated stimulus presentations. It is associated with an increase in the relative importance of the response to the first stimulus in a train for correct recognition of the stimulus chosen. Event-related potentials (ERPs) in response to the first stimulus presentations are known to have their own specificity. Particularly, in many cases, the amplitude of the response to the first presentations is enhanced, which makes it very suitable for recognition in a BCI. However, this effect has not been studied to date. In this study, the ERPs recorded in healthy subjects in a standard BCI paradigm (n = 14) with ten presentations of stimuli or during triple-trial (n = 6) and single-trial (n = 6) presentations of stimuli in a modified BCI paradigm with moving objects have been analyzed. In both cases, first presentations of the target stimuli or single-trial presentation of the target stimulus were associated with higher amplitudes of ERPs. The opportunity to use specific differences between the responses to the first or single-trial presentations and the responses to later stimuli during their repeated presentations for improving high-speed operations in the P300-based BCI is discussed.     

A portable reflectometric photometer for quantitative enzyme immunoassay

A portable optoelectronic reflectometric photocolorimeter was designed. The photocolorimeter implements two operating modes (transmission and reflection), and its performance was tested in two systems of enzyme immunoassay for testosterone: microplate ELISA and membrane dot-ELISA. The detection threshold for microplate ELISA and membrane dot-ELISA was 0.1 and 0.6 ng/ml, respectively. The coefficient of correlation between the photocolorimeter readings and conventional photometric methods is r=0.999. Relative standard deviation of the results of photocolorimetric measurements (n = 4) within the optical density range of 0.03 to 1.00 ranged from 3.4 to 0.7%. The simple and versatile design of the photocolorimeter makes it appropriate for testing various substances both in laboratory settings and in the field.     

Manifestation of Solar–Terrestrial Rhythms in Variations of the Electrical Conductivity of Water

Biophysics - Variations of electrical conductivity of distilled water were continuously measured for 1 month. Long-period (up to 7 days or longer) variations were observed in electrical...     

Systematic approach to studying proteins from human platelets. Two-dimensional mapping]

Total proteins of human platelets and their membranes were studied by two-dimensional electrophoresis using the lysis in sodium dodecyl sulfate solution. Analysis of platelets from 30 donors revealed the presence of 105 repeating fractions on the electrophoregrams. A two-dimensional map of platelet proteins in the molecular mass versus relative electrophoretic mobility plot was constructed. This map made it possible to localize membrane proteins and albumin as well as a protein immunologically related to phenylalanine hydroxylase. Electrophoretic variants of 13 platelet polypeptides were identified.     

Post-mortem decay of rat skeletal muscle polysomes]

Post-mortem changes of cytoplasmic RNP particles from rat skeletal muscles are studied using sucrose density gradient. The polysome destruction is found to beign within 1-2 hours after the animal death. However, a part of polysomes turned to be stable at least within 48-60 hours after the death. These polysomes incorporated 14C-leucine into acid insoluble fraction in cell-free system and were decomposited by RNase treatment (10 mkg/ml). The data suggest that within 24-48 hours of the after-death destruction the decay begins to free monoribosomes while there are still active polysomes in muscles.     

Functional variability of the indices of ventilation and gas exchange in healthy young men in Western Siberia

The variability of standardized values of indices of the external respiration function (ERF) of healthy young men living in Western Siberia has been estimated. Three different states of ERF have been found: (i) normal respiration (normal ventilation efficiency at different levels); (ii) compensatory hyperventilation, during which the ventilation apparatus is strained, which indicates that there are some changes in the morphological structure of the respiratory regions of the lungs (this state can be considered a borderline between the normal state and pathology); and (iii) deep, highly effective respiration; it has no signs of the tension of the function or the apparatus of external respiration, and it can be considered a normal genotypic/phenotypic variant.