[The morbidity rate among machine operators in the Kurgan Region]. / Zabolevaemost' mekhanizatorov Kurganskoi oblasti.

The research results of complex medical examinations among machine-operators (age: 18-60, labor record: 1 to 20 years) are described in the paper for 12 district of the Kurgan Region.

Which factors are responsible for the changing lichen floras of London?

SO(2) is no longer the principal factor influencing the vitality and composition of lichen assemblages in London. We provide direct evidence for an impact on lichen growth during episodic high exhaust emissions coupled with unusual climatic conditions. This suggests a combination of particles and nitrogen plays a major role in influencing lichen growth. Nitrogen from traffic emissions may be at least as important as agriculture in influencing the composition of lichen assemblages.

[The effect of the genome of the variety on the adaptive characteristics of alloplasmic strains of winter wheat]. / Vliianie genoma sorta na adaptivnye osobennosti alloplazmaticheskikh linii ozimoi pshenitsy.

The analysis of adaptability and genetical distances between 12 cytoplasms of Aegilops, Triticum and Haynaldia villosa for three winter wheat genomes showed an existence of genome-plasmon interactions. The plasmons of Ae. variabilis, Ae. cylindrica, Ae. squarrosa var. strangulata, T. dicoccoides appeared to be perspective in practical breeding for adaptability. Interactions are revealed as alteration of productivity and adaptability, and as genetic divergence.

[Defect of preferential repair of gamma-ray-induced single-strand breaks in transcribed and non-transcribed DNA in Cockayne syndrome cells]. / Defekt preimushchestvennoi reparatsii gamma-indutsirovanny odnonitevykh razryvov v transkribiruemoi i netranskribiruemoi DNK pri sindrome Kokeina.

The repair of gamma-ray-induced DNA single-strand breaks in transcribed (protooncogene c-myc) and non-transcribed (human satellite III) DNA of normal human fibroblasts and fibroblasts obtained from a patient with Cockayne's syndrome (CS) has been investigated. A method of alkaline sucrose sedimentation was applied besides the Southern hybridization of 32P-DNA, containing sequences analysed with total 3H-DNA distributed through sucrose gradient fractions. No increase in the induction of DNA single-strand breaks was found in gamma-irradiated CS fibroblasts, compared to normal human fibroblasts. At the same time, an evident defect in the preferential repair of single-strand breaks in c-myc gene was observed.

[Theoretical substantiation and results of licensing and accreditation technology in a region]. / Teoreticheskoe obosnovanie i rezul'taty tekhnologii litsenzirovaniia i akkreditatsii v regione.

Experience gained in licensing and accreditation of central regional hospitals in the Kurgan region is presented.

[The repair of gamma-induced single-stranded breaks in the transcribed and nontranscribed DNA of HeLa cells]. / Reparatsiia gamma-indutsirovannykh odnonitevykh razryvov v transkribiruemoi i netranskribiruemoi DNK kletok HeLa.

The repair of gamma-ray-induced DNA single-strand breaks (SSB) in transcribed (Alu-enriched DNA, proto-oncogene c-myc) and non-transcribed (human satellite III) DNA of HeLa cells has been investigated. A special methodical approach has been developed. The method involved alkaline sucrose sedimentation followed by Southern hybridization in situ of 32P labelled plasmids (probes) containing sequences analysed with total DNA distributed through sucrose gradient fractions. The degree of the probes hybridization with cellular DNA was the criteria of the damage and that of DNA repair. The induction of DNA SSB after irradiation (100 Gy) in Alu-enriched DNA and c-myc gene was shown to be 1.3-1.4 time more often while than in satellite DNA, and 1.4 time lower compared to that in total DNA. The rate of DNA repair was different: the most part of lesions was eliminated in the first 10-20 minutes in all cases. For this time 60-67, 50-66, 35-50 and 45-50% DNA SSB were eliminated from transcribed DNA (c-myc, Alu), non-transcribed DNA (satellite III) and total DNA, respectively. Thus, the preferable (fast) repair of gamma-ray-induced DNA SSB takes place in transcribed DNA compared to that in non-transcribed DNA of HeLa cells.

[DNA repair in cells of the radiosensitive mutant of Drosophila rad(2)201GI after gamma-irradiation]. / Reparatsiia DNK v kletkakh radiochuvstvitel'nogo mutanta drozofily rad(2)201GI posle gamma-oblucheniia.

A radiosensitive mutant of Drosophila melanogaster rad(2)201GI was analysed for the capacity to repair DNA single- and double-strand breaks induced by gamma-rays. Analysis was performed on cell cultures derived from embryos of homozygous mutant stock and wild type strain Oregon R. The viability of irradiated cells was studied. It was shown that the mutant strain cells had increased lethality, just like a whole organism. Single-strand breaks were analysed by alkaline sucrose gradient centrifugation; double-strand breaks were monitored by neutral elution. The similarity of repair kinetics of single- and double-strand breaks in cells of rad(2)201GI and Oregon R was shown. Probable molecular mechanisms of rad(2)201GI mutant radiosensitivity are under discussion.

[The regulation of the DNA repair process in mammalian cells. IV. The role of DNA polymerases in the epidermal growth factor regulation of the repair of single-stranded DNA breaks induced by ionizing radiation in Swiss 3T6 mouse cells]. / Reguliatsiia protsessov reparatsii DNK v kletkakh mlekopitaiushchikh. IV. Rol' DNK-polimeraz v reguliatsii épidermal'nym faktorom rosta reparatsii odnonitevykh razryvov DNK, indutsirovannykh ioniziruiushchei radiatsiei, v myshinykh kletkakh Swiss 3T6.

A study was made of the repair of ionizing radiation-induced DNA single-strand breaks (SSB) in proliferating and quiescent mouse Swiss 3T6 cells and in those stimulated from the quiet status by epidermal growth factor in combination with insulin, in the presence of specific inhibitors of DNA polymerase alpha and delta (aphidicolin) and DNA polymerase beta (2', 3'-dideoxythymidine-5'-triphosphate). The repair of DNA SSB induced by X-ray-irradiation (10 Gr) or by gamma-ray irradiation (150 Gr) is more sensitive to aphidicolin independently of cell proliferating status. Aphidicolin inhibits the recovery of single-strand DNA in quiescent and mitogen-stimulated cells three times stronger than in proliferating cells. The influence of 2', 3'-dideoxythymidine-5'-triphosphate on the rate of DNA SSB repair in cells of all the three types does not differ. Thus, the decrease in DNA repair efficiency in quiescent cells is connected with a decrease in the activity of aphidicolin-sensitive DNA polymerase, apparently DNA polymerase alpha. It is suggested that the regulation action of mitogens on the DNA SSB repair may be determined by qualitative changes of this enzyme or of some conditions in which it functions. The involvement of DNA polymerase delta in this process is not excluded.

[The regulation of DNA repair processes in mammalian cells. III. The effect of epidermal growth factor on the postradiation recovery of the cell cycle in human A 431 cells and embryonic fibroblasts]. / Reguliatsiia protsessov reparatsii DNK v kletkakh mlekopitaiushchikh. III. Vliianie épidermal'nogo faktora rosta na postradiatsionnoe vosstanovlenie kletochnogo tsikla u kletok A 431 i émbrional'nykh fibroblastov cheloveka.

Recovery of the cell cycle in cells A 431 and in human embryo fibroblasts (EFH) differs much. Unlike EFH, A 431 cells have: 1) synchronized exit of cells from G1 into S phase after 5 Gr irradiation; 2) G2-block; 3) much less manifestation of these two phenomena in the presence of EGF; 4) a lesser effectiveness of the repair of DNA single-strand breaks. EGF stimulation of the repair of radiation-induced DNA lesions, SSB in particular, may be of great importance for the postirradiation cell cycle recovery.

[The regulation of DNA repair processes in mammalian cells. II. The repair of DNA radiation damage in NIH 3T3 murine cells transformed by the v-myc oncogene]. / Reguliatsiia protsessov reparatsii DNK v kletkakh mlekopitaiushchikh. II. Reparatsiia radiatsionnykh povrezhdenii DNK v myshinykh kletkakh NIH 3T3, transformirovannykh onkogenom v-myc.

The kinetics of repair of the ionizing radiation-induced DNA single- and double-strand breaks in the normal NIH 3T3 mouse cells and in those transformed with virus oncogenes v-myc has been investigated. The incubation of non-transformed cells for 18 hours in serum-free medium results in significant decrease in the rate of the single-strand DNA breaks repair during the first minutes of post-irradiation incubation. This effect is absent in transformed cells. The DNA double-strand breaks repair is more efficient in transformed NIH 3T3 cells as compared to that in the non-transformed ones both after their incubation in the medium with 10% fetal bovine serum or without serum. However, more significant differences in the rate of elimination of these DNA lesions was found in the serum-free medium. Hence, the presence of v-myc sequences in the transformed cells prevented from a decrease in the efficiency of DNA repair due to incubation of cell culture in serum-free medium. These results agree with the assumption that c-myc gene product may be a mediator in regulation of DNA repair by the epidermal growth factor. These data also show that the c-myc gene expression in an important condition providing a high efficiency of the constitutive DNA repair process.

[The relationship between the radiosensitivity of DNA replicative synthesis and the formation of sister chromatid exchanges]. / K voprosu o sviazi mezhdu radiochuvstvitel'nost'iu replikativnogo sinteza DNK i obrazovaniem sestrinskikh khromatidnykh obmenov.

It has been found that irradiation in doses 0.5-2.0 Gy does not enhance the frequency of sister chromatid exchanges in cells of patients with Down's syndrome and ataxia-telangiectasia compared to the normal cells. In the case of ataxia, this phenomenon was accompanied with radioresistant replicative DNA synthesis, whereas in two cases of Down's syndrome the replicative DNA synthesis was found to be as radiosensitive as in the norm. According to these data, the mechanism of sister chromatid exchanges proposed in our previous publication (Pleskach et al., 1988) seems to be rather doubtful.

[The regulation of DNA repair in mammalian cells. I. The repair of DNA radiation damages in Swiss 3T6 mouse cells under the action of the epidermal growth factor and insulin]. / Reguliatsiia reparatsii DNK v kletkakh mlekopitaiushchikh. I. Reparatsiia radiatsionnykh povrezhdenii DNK v myshinykh kletkakh Swiss 3T6 pri deistvii épidermal'nogo faktora rosta i insulina.

Methods of centrifugation in alkaline sucrose gradients as well as alkaline and neutral elution on filters were used to show a significant reduction in the rate of both single- and double-strand DNA breaks in the quiescent mouse Swiss 3T6 cell culture as compared to the proliferating one. The low efficiency of repair of single-strand DNA breaks in quiescent cells may result from a nearly complete absence of the fast repair of DNA lesions during the first minutes of postradiation incubation. The epidermal growth factor in combination with insulin (no other serum component present) leads to a recovery of the repair process. The stimulating effect of mitogens on the repair of both single- and double-strand DNA breaks allows to suggest that similar factors may be responsible for these recovery processes.

[Disruption of DNA replication in non-irradiated cells in basal cell nevus syndrome and the effect of ionizing radiation]. / Narushenie replikatsii DNK v neobluchennykh kletkakh pri sindrome bazal'nokletochnogo nevusa i deistvie ioniziruiushchei radiatsii.

Analysis of DNA fiber autoradiograms from basal cell nevus syndrome (BCNS) skin fibroblasts has revealed for the first time a new defect in DNA replication earlier unknown in other chromosomal instability syndromes, that involves a significantly decreased rate of DNA-chain growth in unirradiated cells. Here we present evidence that the defect may be due to a marked reduction in number of simultaneously operating groups of replicons compared to that in normal cells, the rate of fork movement and the fusion of neighbouring units in the group remaining unchanged. Radioresistant DNA synthesis was observed in the BCNS cells. The exposure of cells derived from normal donor to gamma-rays at a dose of 5 Gy reduces the number of simultaneously operating groups of replicons to the level occurring in unirradiated BCNS cells, the rate of folk movement being unchanged in both cell types. However, the incidence of fusion between neighbouring units within the group is lower in the cells exposed to gamma-rays, due perhaps to a radiation-induced lesion in the group. Thus, ionizing radiation reduces the rate of DNA synthesis to the same level, however from different initial levels. Our data suggest that the phenomenon of radioresistant DNA synthesis may be explained by the presence of the initial defect in DNA replication in BCNS or any other chromosomal instability disorders.

[Epidermal growth factor with insulin used for stimulation of exogenous colony formation in the spleen of mice irradiated with lethal doses of X-rays]. / Stimuliatsiia épidermal'nym faktorom rosta sovmestno s insulinom obrazovaniia ékzogennykh kolonii v selezenke myshei, letal'no obluchennykh rentgenovskimi luchami.

Epidermal growth factor (12 ng per 1 g of body mass) and insulin (0.004 units per 1 g of body mass) were introduced into X-ray irradiated (1.8, 2.12, 2.7 Cr) mice. Four hours later bone marrow was extracted from femurs to be introduced into syngenic lethally irradiated recipients. On the 11th day after transplantation the number of exogenic spleen colonies was computed. The epidermal growth factor, in combination with insulin, stimulates in the organism the restoration of hemopoietic colony-forming cells after radiation injury.