Identification of a new seventh complementation group of UV-sensitive mutants in Chinese hamster cells

The UV-sensitive mutant V-B11, isolated from the V79 Chinese hamster cell line (Zdzienicka and Simons, 1987) was further characterized. V-B11 has a slightly increased cross-sensitivity to 3me4NQO, whereas no increased sensitivity towards 4NQO was observed. A slightly increased sensitivity towards EMS and MMS was also found. The mutant shows a defect in the ability to perform the incision step of nucleotide-excision repair after UV irradiation: 2 h after UV exposure, the accumulation of incision breaks in V-B11, in the presence of HU and araC, was about 30% of that found in wild-type V79 cells. V-B11 was crossed to a panel of 6 UV-sensitive Chinese hamster ovary (CHO) cells, which represents all the previously identified 6 complementation groups of UV-sensitive Chinese hamster mutants. Since in all crosses complementation has been observed, V-B11 appears to be the first mutant of a new, 7th, complementation group.     

Effect of external gamma radiation on shortening the life expectancy and rates of the formation of absorbed doses from incorporated 239Pu in dogs

External gamma irradiation of dogs with doses of 103.2 and 51.6 mC/kg combined with the effect of inhaled plutonium-239 accelerates the formation of absorbed doses in secondary organs of the radionuclide deposition by 41.7 and 2.4 times, respectively, whereas the dose of 25.8 mC/kg is ineffective. As estimated by the rate of 239Pu accumulation and by the life span shortening, the minimum effective and the maximum ineffective doses are 104.8 and 80.5 cGy and 89.2 and 79.2 cGy, respectively.     

Electron microscopic and electron radioautographic study of cells in glandular hyperplasia and cancer of the endometrium

Peculiarities of the ultrastructure and RNA synthesis in the epithelial endometrial cells of nine patients with hyperplasia and the uterine cavity cancer have been studied by the electron-radioautographic method. Quantitative differences are revealed in the ultrastructures of the cells. Amplification of the nucleoli labelling and asynchronism of the RNA synthesis in the nucleoli with glandular hyperplasia and endometrial cancer are observed.     

The isolation and immunological properties of two arginase forms from human erythrocytes

1. Two forms of arginase were isolated from human erythrocytes; the main form adsorbed on CM-cellulose and the second form, occurring in much smaller amount, adsorbed on DEAE-cellulose. 2. The molecular weight of either arginase was 120,000 +/- 5000. 3. The erythrocyte arginases are similar in immunological properties to arginase A4 from human kidney and A2 from human liver, respectively. 4. Despite the literature data stating that human erythrocyte arginase and human liver arginase are identical, it was found that the main forms of arginase of these tissues A4 from erythrocytes and A5 from liver differ in immunological properties.     

Histochemistry of proteases in ependyma,choroid plexus and leptomeninges

Summary Aminopeptidase M (APM), aminopeptidase A (APA), dipeptidyl peptidase IV (DPP IV) and -glutamyl transferase (GGT) were demonstrated histochemically in cryostat sections of the rat brain to show the reaction pattern of ependyma, choroid plexus and leptomeninges. GGT was only demonstrable in the cell membranes of ependymal cells and in the leptomeninges; however, APA, APM and DAP IV showed a variable degree of activity in the capillary endothelium of the choroid plexus as well as in the leptomeninges. On the basis of these results, it is postulated that peptides in the cerebrospinal fluid can be cleaved extraventricularly by the enzymes demonstrated in the leptomeninges.Dedicated to Professor Dr. T.H. Schiebler on the occasion of his 65th birthday     

Effect of n-3 and n-6 fatty acids on hepatic microsomal lipid metabolism: a time course study

The present study examines the time dependent effects of n-6 and n-3 polyunsaturated fatty acids on liver microsomal lipid metabolism in FVB mice fed a diet supplemented with a mixture of free fatty acids (mainly 18:3n-6 and 20:5n-3) at 25 mg/g diet. Significant changes in the fatty acid composition of total liver and microsomal lipids were observed after 7 days on the diets. Thereafter, some animals remained on the same diet while others were fed a diet supplemented with hydrogenated coconut oil (HCO). With the exception of 20:5n-3 which showed a slower recovery, establishment of the HCO pattern was rapid indicating that the diet-induced changes could be easily reversed. The unsaturation index, the cholesterol/phospholipid ratio and the microviscosity of the microsomal membranes were not affected by these dietary manipulations. Unsaturated fatty acid supplementation reduced the activity of ⁹ desaturase by 50%. Feeding the HCO diet to mice previously fed the EPA/GLA diet led to a progressive increase in ⁹ desaturase activity, reaching 80% of the day zero values after 14 days. The monoene content of hepatic total lipids reflected, in most cases, the changes in enzyme activity. This study shows that a low dose of a n-3 and n-6 free fatty acid mixture increases the quantities of members of the n-3 family, without loss of n-6 fatty acids in microsomal membranes and modifies the activity of ⁹ desaturase without altering the microsome physicochemical parameters.     

The histological evaluation of the effect of Bacillus intermedius RNAse on the organs of immunogenesis in laboratory animals]

Histological changes in organs of immunogenesis of experimental animals after RNAse Bacillus intermedius treatment have been studied. The effect of RNAse on organs is revealed in activation of both cell and humoral immunity and factors of nonspecific resistance at early stage of reaction. The inhibition of immunological reactions and factors of nonspecific resistance takes place at later stages of enzyme action. The caused effects don't depend on catalytic enzyme activity.