Dynamics of cardiac performance in athletes during isometric exercise

The main structural-functional indices of cardiac performance during isometric exercise were recorded in athletes and non-athletes. The physiological shifts in response to exercise were less obvious in the athletes than in the non-athletes. This was mainly determined by the structural features of the “athlete’s heart.” The dependence of a series of physiological indices on the heart rate was revealed: as cardiac rhythm increased in response to a submaximal isometric exercise, the systolic and, to a lesser degree, diastolic arterial pressure grew and the stroke volume of blood decreased.     

A novel intramolecular G-quartet-containing fold of single-stranded d(GT)8 and d(GT)16 oligonucleotides

Human genome is shown to be enriched with (GT)_n stretches of lengths from 8 to 20 dinucleotides. Low temperature (T ≤ 10 °C) conformations of d(GT)_n oligonucleotides (n = 7, 8, 12, 16, 20) were studied by means of circular dichroism (CD), thermal melting, ethidium bromide (EtBr) probing and single nucleotide substitutions. Rotational relaxation times for EtBr:d(GT)_n complexes confirmed a monomolecular state of the oligonucleotides. CD spectra indicated involvement of all guanines of d(GT)₈ and d(GT)₁₆ in G-quartets, while dT(GT)₇, d(GT)₁₂ and d(GT)₂₀ were shown to be only partially ordered. The schemes of the d(GT)₈ and d(GT)₁₆ folds are suggested.     

Light and electron microscopical investigations on the tanycyte differentiation during the perinatal period in the rat

Summary The differentiation of tanycytes was studied light and electron microscopically during the perinatal period in rats, the time when functional connections between hypothalamus and hypophysis are established. The 3rd ventricle is slit-like between 16 and 18 days of the prenatal period. Its wall is formed by intensively proliferating matrix cells with apical processes, ovoid perikarya and a basal process. The ventral region of the 3rd ventricle becomes funnel-shaped on the 20th day of the prenatal period. As the cells differentiate, the apical process becomes shorter and broader. Moreover, on day 20 of prenatal life cells without apical processes appear. Their number increases during the postnatal period. The concentration of endoplasmic reticulum, mitochondria, polysomes, lipid droplets, dense bodies (lysosomes), lamellated and multivesicular bodies increases. Initially the cells are similar but from the 3rd day of postnatal life differentiation occurs in different regions of the infundibular recess. After the 5th day, there are no marked changes in the structure and distribution of these cells.K. Chandrasekhar wishes to thank the Indian National Science Academy and USSR Academy of Sciences for the award of a fellowship during the tenure of which this work was completed     

Hemodynamic Response to Static and Dynamic Physical Exercise in Athletes

Athletes with different levels of physical work capacity were examined to determine the main echocardiographic indices, measure the arterial blood pressures, and record the electrocardiograms. The athletes with a higher level of physical work capacity and a more pronounced structural and functional cardiac changes performed both dynamic and static exercise more efficiently. Compared to dynamic exercise, the static exercise caused greater exertion in athletes, i.e., higher values of systolic and diastolic pressure and oxygen consumption.     

Cellular immunity function in HIV-1-infected persons

The data on the state of cell-mediated immunity in patients with AIDS-related complex are presented. The synthetic peptide of membrane protein gp120 of HIV-1 was shown to inhibit leukocyte adhesion in persons under examination, as well as to have the tendency towards inhibiting the chemotaxis of migratory cells. The maximum effect was achieved at a peptide concentration of 10(-6) M. The data obtained in this investigation suggest the presence of specific cell-mediated sensitization to the fragment of protein gp120, detected by the adhesion inhibition test with the use of spectrophotometric techniques and the capillary evaluation of the chemotaxis of migrating cells, in patients with AIDS-related complex.