Human chorionic gonadotropin: Unknown about known

The last two decade discoveries shift the accent from the consideration of human chorionic gonadotropin (hCG) as a hormone that controls progesterone production by corpus luteum cells to a powerful paracrine regulator that, in the tandem with its hyperglycosylated analog (h-hCG), induces successful implantation and coordinated dialog between blastocyst and uterine tissues. The ability of hCG and h-hCG to interact with TSH receptor and TGF-beta-RII, respectively, significantly extend the spectrum of processes controlled by these molecules. Differences between intracellular pathways of signal transduction between hCG and LH mediated by the same receptor (LH/hCG-R) impugn the unity of their effector mechanisms, which was previously considered as obvious. The paracrine properties of hCG include the control of fusion of trophoblasts into syncytiotrophoblasts, angiogenesis, immunity regulation, and endometrium predisposition to implantation. Angiogenesis is associated with LH/hCG-R expressed on mural cells of uterine spiral arteries as well as induced secretion of soluble VEGF form by endometrial cells. hCG regulates the ratio between different types of T-helper cells in maternal organism at the initial gestation stage determining a high level of Th2 cells. hCG supports local immunotolerance, functioning as a chemoattractant for T-suppressors (T-Treg) and an apoptotic factor for T-lymphocytes. Endometrial susceptibility arises from the activation of osteopantin secretion and the decline of mucin secretion by epithelial cells. h-hCG affects the same tissues as hCG, functioning as a paracrine agent regulating multiple cascades of cytokines. h-hCG plays the key role in the trophoblast invasion into the uterine decidua as a result of gelatinase secretion by these cells. The degree of the angiogenic effect of h-hCG is compatible with that of hCG, but its signal transduction is mediated by the TGF-beta signal transduction pathway that stimulates mural cell proliferation. h-hCG acts as a mitogen on NK-cells and is able to activate them and direct to angiogenesis maintenance. In this article, we attempted to elucidate the most important discoveries about the role of hCG and its hyperglycosylated analog, both accomplished and still upcoming.     

Adaptive reactions in humans during repeated exposure to deep-water saturation immersion]

Evaluation of changes in respiration circulation and respiratory gas transport has shown that long-term influence of hyperbaria gives rise to phase changes and promotes a shift to a new level of the functional state of aquanauts. It is established that the postdecompression syndrome is characterized by the lability of main parameters of breathing and circulation, depression of gas exchange, disorders of bronchial permeability, relaxation of the cardiac pump function, decrease of physical workability against the background of inhibition of the adrenal cortex and weakening of the non-specific immunoresistance. Examination of 145 deep divers has revealed regularities of readaptation dynamics and has permitted a conclusion on an increase of unfavourable tendencies in the ventilatory pulmonary function and cardiac pump function under repeated effect of saturated diving. The normative values of external respiration are worked out as applied to divers. Some new approaches to the technology of medical providing of deep divings and correction of non-specific professional pathology of acquanauts are physiologically substantiated proceeding from tendencies of shifts in the periods between divings and diving norms.     

First Results of the RAMBAS Experiment on Investigation of the Radiation Mechanism of Chiral Influence

The first results of the RAdiation Mechanism of Biomolecular ASymmetry (RAMBAS) experiment on investigation of the radiation mechanism of the influence on chiral molecules, as a factor leading to origination of chiral asymmetry are presented. It was found that irradiation of simple achiral materials by a flux of electrons from radioactive source initiated the synthesis of amino acids, and it resulted in asymmetric degradation and chiral asymmetry in a racemic mixture of amino acids. The results obtained can be important for the solution of the origin-of-life and biological homochirality problems.     

Method for determining the functional state of the human respiratory and circulatory systems in underwater conditions]

An original device has been worked out which permits registering parameters of respiration, gas exchange and circulation in man during diving and performance of some tests under water (graduated exercise, respiration with changed gas mixture, etc.). The correction coefficients have been experimentally determined to calculate the gas exchange and cardiohemodynamics indices in underwater conditions. The indices of human work capacity under water are determined using the above device.     

Hemoglobin oxygen affinity in Mesocricetus auratus hamsters of different ages

Studies have been made on the amino acid composition of electrophoretically homogeneous albumin and its main isoelectrically homogeneous fraction in two strains of hens and their hybrid. Serum albumin of hen and hybrid is characterized by higher total content of Asp and Glu residues as compared with that of the cock (137, 121, and 116 respectively) and lower content of Lys (59 against 66). The acidity of albumin increases in the line cock-hen-hybrid. With respect to its amino acid composition, the maternal serum albumin stands close to the hybrid one.