Evaluation of cell proliferation kinetics by the differential staining of the sister chromatids at 2 points of cell fixation

Lymphocyte proliferation in blood cultures from 23 normal individuals was studied. A simple method of evaluation of cell proliferative kinetics with sister chromatid differential staining using two different points of cell harvesting was suggested. It was shown that different composition of tissue culture medium plays a significant role during the cell exit from G0 stage, the mean doubling generation time of cellular population remaining constant.     

Effect of helium and argon on the oxygen uptake by lymphocytes

The effect of inert helium and argon gases on the tissue respiration has been studied on lymphocyte suspensions of white rats. It is shown that normoxic helium-oxygen mixture induces almost a two-fold increase of the O2 uptake by lymphocytes as compared with the control (air). No deviations in the value of the studied parameter are revealed in case of replacement of nitrogen from air by argon. Significance of the membrane structure in realization of effects of inert gases is under discussion.     

A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

A complex medico-genetic study of West Siberian populations. I. Formulation of a problem. Goals and objectives of the study. Population genetic characteristics of Northern Khanty

Purposes and tasks of the complex medical and genetic study of West-Siberian inhabitants were formulated. Demographic parameters for the North Khanty inhabitants, such as size, dynamics of the tertiary sex ratio, marriage structure and migration processes were presented. Mating and intrapopulation migration patterns are determined by spatial subdivision, because of the vast territory and the traditional way of life, and by isolation by distance. Index of the isolocal endogamy equals to 0.364. The portion of mixed marriages is 22.7% and that of the gametic contribution of immigrants - 7.3%. Inbreeding coefficient by isonymy is 0.00097. Effective population size of the five subpopulations studied as a whole is 25% of their total number.     

Determination of inhibition sites during hydrolysis of polydeoxyribonucleotides by exonucleases III from Bacillus amyloliquefaciens and Escherichia coli

The influence of the primary structure of polydeoxyribonucleotides on the rate of hydrolysis with exonuclease III from Bacillus amyloliquefaciens and Escherichia coli was investigated. The substrates used were synthetic oligodeoxyribonucleotides and pBR 322 DNA fragments labeled with 32P at the 5'-termini of one of the chains. According to the data from polyacrylamide gel electrophoresis performed under denaturing conditions, the hydrolysis of these substrates by unsaturating concentrations of B. amyloliquefaciens and E. coli exonuclease III proceeds with several reproducible "stops". The decrease of the reaction rate was shown to take place just before the pyrimidine blocks in the digested DNA chain.     

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.     

Separation of dissociated thyroid follicular and parfollicular cells: association of serotonin binding protein with parafollicular cells

Parafollicular cells (PC) of the sheep thyroid gland are neural crest derivatives that synthesize and release the biogenic amine serotonin (5-HT) as well as the hormone calcitonin. The thyroid also contains a highly specific serotonin-binding protein (SBP). Separation of dissociated thyroid cells was done to study the cellular localization of SBP and to develop a means of isolating PC for study. Various methods were used to obtain an enriched and purified population of PC. Minced thyroid glands were enzymatically dissociated and the cells were layered on a Ficoll linear density gradient. Fractions obtained from the gradient were examined for cell number, viability, 5-HT concentration, SBP activity, and morphology by electron microscopy. One of the fractions was found to be enriched in PC. High levels of 5-HT and SBP were also found in this fraction, whereas these levels were low where the majority of cells were found. This PC-rich fraction, however, contained numerous follicular cells (FC); therefore, additional approaches to cell separation were used. FC can be stimulated in vitro with thyroid stimulating hormone (TSH) to become intensely phagocytic. When stimulated cells were incubated in the presence of silica microspheres, the FC engulfed the microspheres, which were toxic to them. PC did not become phagocytic and were unharmed by the microspheres. Suspended cells, after incubation with microspheres, were centrifuged on a discontinuous gradient, and a PC-rich fraction was obtained. Silica, however, interfered with analysis of SBP. Another method to take advantage of the phagocytic potential of FC was therefore used. TSH-stimulated cell suspensions were passed through a column of sepharose to which thyroglobulin had been coupled. Stimulated FC apparently adhered to the beads and were retained by the columns. Fractions eluting from the columns were greatly enriched with PC. These fractions contained high levels of 5-HT and SBP, and considerably reduced FC contamination was found by quantitative electron microscopy. It is concluded that SBP is localized to PC in the sheep thyroid. The idea that these cells resemble serotonergic neurons in their mechanisms of 5-HT storage is supported.     

Oxygen binding of myoglobins of diving animals]

When studying oxygen binding by myoglobins of diving animals it is shown that half-saturation of myoglobins obtained from the muscles of animals who can stop the external respiration for a long period of time occurs at oxygen strength of 0.62-0.67 mm Hg. Such indices of oxygenation of respiratory hemoprotein of muscles are characteristic of most mammals. Temperature being decreased from 37 to 15 degrees C, myoglobin affinity to oxygen considerably increases.     

Mechanism of ethonium effect on membrane preparations of brain Na+, K+-ATPase

The effect of ethonium, a local anesthetic, on the membrane preparations of brain N+, K+-ATPase was studied by fluorescent, radioisotopic, electron-microscopic and electrophysiological methods. Ethonium is established to affect the formation of an intermediate phosphorylated product and has no pronounced destructive effect on the membrane. It changes the fluorescence intensity of 2-toluidinonaphthalen-6-sulphonate (TNS), astrafloxin (AF) and fluorene probes in a suspension of the Na+, K+-ATPase preparations, which evidences for ethonium-induced changes in the structure of membrane fragments.