Immunoglobulin kappa-genes. Cloning, hybridization and structural analysis

The principal problems in molecular and genetic immunology to be resolved are the structure of Ig-genes and the regulation of their expression. The isolation of mRNA for light and heavy Ig-chains would be a first step along this line. A combination of two approaches may be the best strategy in mRNA preparation. Affinity purification allows one to obtain pure mRNA in a one-step procedure whereas immunoprecipitation makes it possible to prepare mRNAs for both heavy and light immunoglobulin chains in considerable amounts. In the series of experiments, conditions for synthesis of long and short cDNA chains were elaborated and the clone containing the fragment of kappa-chain gene was isolated and characterized. This clone was used as a probe for hybridization with genomic DNA from myeloma and hybridoma cells. It was shown that both allelic genes on homologous chromosomes were rearranged in myeloma MOPC21 cells. The original cell line of hybridoma PTF02 contains the embryonic gene as well as the differentiated genes. However, only differentiated genes can be detected in a similar experiment conducted with the same hybridoma after passage on mice. In conclusion, the coordination of homologous and heterologous chromosome expression in B cells in discussed in terms of the feed-back control.     

Radiation reactions and the possibilities for their modification in rats exposed in the area of the Chernobyl Atomic Electric Power Station]

A study was made of some embryological, hematological, cytogenetic and biochemical characteristics in Wistar rats exposed within the Chernobyl NPP zone over a period of 30 days (the average radiation background level, 75, and at the soil surface, 115 mR/h; a cumulative dose, 57 rad/30 days, and for pregnant rats, 36 rad/20 days). The quantity of chromosome aberrations in bone marrow metaphases and the embryonal death rate were invariable; some cases of teratogenesis were, however, observed. The total number of karyocytes in the brain and the leukocyte content in the peripheral blood sometimes decreased. The changes in certain characteristics (such as the content of endogenous amines and thiols in the liver and spleen) of the endogenous radioresistance background (ERB) and the normalization of the ERB by the radioprotective agent MIGI-K were found.     

Utrastructural interrelationships of collagen fibrillar components in human connective tissue]

The data on structural interconnections between collagenous fibres in the human dermis and periosteum were obtained by means of raster electron microscopy. Collagenous fibres were demonstrated to be connected with each other by means of fine connective fibres situating mainly transversaly towards the main collagenous fibres. Comparing the data obtained with those from the literature, a suggestion was made on the existence, in the connective tissue, of a special connective system composing of peculiar fibrillar structures which maintains dynamic equilibrium in arrangement of collagenous fibres, muscles, vessels, etc. The system of the connective fibres demonstrates a common compositional principle for all the structures mentioned above, but in every case having its peculiarities.     

The effect of carnosine on the liver enzyme system in the irradiated body]

The effect of carnosine on post-radioactive changes in lipid peroxidation (LPO) products in blood serum and cytochrome P-450 content in liver microsomes has been studied. Per os administration of carnosine 24 hours prior to irradiation in a minimal lethal dose (7 Gr) markedly decreases the post-radioactive accumulation of LPO products in rat blood serum one hour after irradiation and fully restores the post-radioactive decrease in the cytochrome P-450 content in rat liver microsomes on day 5 after irradiation. Besides, the ability of carnosine to prevent the post-radioactive decline in the activity of UDP-glucuronyl transferase. Another key enzyme of the liver detoxifying system, has been demonstrated. The data obtained testify to the ability of carnosine to provide effective protection against post-radioactive intensification of LPO in irradiated organisms.     

Biophysical basis of medical thermovision

Characteristics of the thermal relief of the human body are reviewed. It is shown that the usage of thermovision in medical diagnostics requires simultaneous and compatible consideration in the research process of three components: the contribution of the object itself, the influence of the medium through which the infrared radiation passes and the instrumental parameters of the infrared imager registering this radiation.     

Increase of the negative charge of erythrocyte membrane proteins in hereditary neuromuscular diseases

The parameters of erythrocyte ghost protein's fluorophores by nitrate's anions were studied in patients with various hereditary myodystrophy. In all the groups under examination the share of fluorophores accessible to a quencher was close to 1. In erythrocyte membranes of healthy donors the relevant constant quenchering was about 17.3 +/- 1.9 M-1 while those of patients were decreased by 3.1 (Duchenne's myodystrophy) and by about 2.0 (other forms of primary and secondary progressive muscular dystrophies). The most probable reason for the decreasing constant of quenchering is the increase of negative charges on the erythrocyte membrane proteins.