Effect of retinoic acid on the aggregation of erythrocytes and leukocytes in the blood

Human and animal blood smear staining with PAPh has revealed mononuclear leukocyte-erythrocyte aggregates. Administration of retinoic acid increased concentration and dimensions of these aggregates and was followed by preferential accumulation of PAPh-negative osmotically unstable erythrocytes. Similar changes were detected in the blood samples of women engaged in the production of retinoic acid. Aggregate concentration showed positive correlation with erythrocyte sedimentation rate and no correlation with prothrombin time.     

Recovery from potentially lethal damage of irradiated L5178Y-R and L5178Y-S cells: the effect of temperature and benzamide

Mouse lymphoma L5178 Y-S and Y-R cells differing in radiosensitivity by 1.5 times were treated with benzamide, an inhibitor of poly(ADP-ribosylation), for 24 h before and 18 h after X-irradiation, and incubated after irradiation at 25 degrees C and 37 degrees C. Clonogenic capacity of LY-S cells incubated at 25 degrees C exceeded that of the same cells incubated at 37 degrees C; the clonogenic capacity of LY-R cells did not vary with the postirradiation incubation temperature. Benzamide increased equally the radiosensitivity of LY-R cells incubated at both temperatures, whereas that of LY-S cells was only increased at 37 degrees C. Repair of potentially lethal damages to LY-S cells incubated at 25 degrees C was independent of the effectiveness of poly(ADP-ribosylation).     

DNA replication in mammalian cells after the action of physical, chemical or biological factors. VI. The recovery of DNA synthesis in a culture of irradiated cells

The kinetics of DNA synthesis restoration in cultured HeLa cells and in L-929 mouse fibroblasts irradiated by gamma-rays of 60Co with a dose of 10 Gy was studied. Early after irradiation the rate of DNA synthesis in HeLa cells measured with 3H-thymidine incorporation was seen to decrease. Two hours later the incorporation starts to increase to reach the control level 4 hours after irradiation and then becomes even higher than this level. The distribution of cells among phases of the cell cycle measured with flow cytometry undergoes changes. 4-6 hours after irradiation part of S-phase cells increased contributing presumably to the elevating of 3H-thymidine incorporation observed at this time. The restoration of the incorporation was suppressed by inhibitors of protein and RNA synthesis--cycloheximide and actinomycin D. It is suggested that the processes of restoration of DNA synthesis in irradiated cells can be of inducible nature. In irradiated HeLa and L-929 cells the restoration of DNA synthesis is resistant to novobiocin, an inhibitor of DNA replication.     

Oxygen radical-mediated mutagenic effect of asbestos on human lymphocytes: suppression by oxygen radical scavengers.

The mutagenic effect of chrysotile asbestos fibers and zeolite and latex particles on human lymphocytes in whole blood has been studied. It was concluded that their mutagenic activities were mediated by oxygen radicals because they were inhibited by antioxidant enzymes (SOD and catalase) and oxygen radical scavengers (rutin, ascorbic acid, and bemitil). It was proposed that oxygen radicals were released by phagocytes activated upon exposure to mineral dusts and fibers. The study of lucigenin- and luminol-amplified chemiluminescence of peritoneal macrophages stimulated by chrysotile fibers and zeolite and latex particles has shown that their mutagenic action is probably mediated by different oxygen species, namely, by the iron-oxygen complexes (perferryl ions) plus hydrogen peroxide, hydrogen peroxide, and superoxide ion, respectively. From the oxygen radical scavengers studied, rutin was the most effective inhibitor of the mutagenic effect of mineral fibers and dusts.     

Determination of the radiosensitivity of interphase-dying cells in the thymus, spleen and bone marrow of rats by flow cytometry

The flow cytofluorometry of cells stained with a DNA-specific probe was used to determine the share of dying cells (containing less than 2C DNA) in thymus, spleen and bone marrow cells of irradiated rats. The cell death curves for spleen and bone marrow had a plateau by the 6th h, and for thymus, by the 10th h following irradiation with different doses. On the basis of the dose-response relationship the share of cells dying in the interphase was determined in each organ under study, and dose-response curves shaped. All the curves had no shoulder. Do was 3.0, 3.0 and 3.7 Gy for thymus, spleen, and bone marrow cells, respectively.     

Radiation response of clonogenic cells of solid tumors. Clonogenic capacity of the murine NKLy solid tumor and its oxygen status

Clonogenic capacity and oxygen tension were determined in peripheral and central zones of solid tumors NKLy in vivo. With low pO2 in central zones (2.69 +/- 0.60 as opposed to 4.64 +/- 0.68 mm m. c. in peripheral zones) and in the presence of anoxic sites, the effectiveness of cloning, with inoculation immediately after isolation of cells from central zones, did not differ from that from peripheral ones (6.36 +/- 0.45 and 6.78 +/- 0.68%, respectively).     

Radiosensitizing effect of interferon synthesis inducers

The preinjection of inductors of leukocytic interferon synthesis of rapid (poly I.poly C, dextransulfate) and slow (tyloron) types to mice bearing inoculated solid sarcoma 37 considerably increases the efficiency of X-irradiation of tumors: the coefficient of tumor growth inhibition (kappa *) exceeds 1.0, and the number of animals with the completely regressed tumors increases. The effectiveness of the procedure depends on the time of the injection of the preparations and modes of irradiation.     

An essential saccharide binding domain for the mAb 2C7 established for Neisseria gonorrhoeae LOS by ES-MS and MSn

A study of bacterial surface oligosaccharides were investigated among different strains of Neisseria gonorrhoeae to correlate structural features essential for binding to the MAb 2C7. This epitope is widely expressed and conserved in gonococcal isolates, characteristics essential to an effective candidate vaccine antigen. Sample lipooligosaccharides (LOS), was prepared by a modification of the hot phenol-water method from which de-O-acetylated LOS and oligosaccharide (OS) components were analyzed by ES-MS-CID-MS and ES-MSnin a triple quadrupole and an ion trap mass spectrometer, respectively. Previously documented natural heterogeneity was apparent from both LOS and OS preparations which was admixed with fragments induced by hydrazine and mild acid treatment. Natural heterogeneity was limited to phosphorylation and antenni extensions to the alpha-chain. Mild acid hydrolysis to release OS also hydrolyzed the beta(1-->6) glycosidic linkage of lipid A. OS structures were determined by collisional and resonance excitation combined with MS and multistep MSn which provided sequence information from both neutral loss, and nonreducing terminal fragments. A comparison of OS structures, with earlier knowledge of MAb binding, enzyme treatment, and partial acid hydrolysis indicates a generic overlapping domain for 2C7 binding. Reoccurring structural features include a Hepalpha(1-->3)Hepbeta(1-->5)KDO trisaccharide core branched on the nonreducing terminus (Hep-2) with an alpha(1-->2) linked GlcNAc (gamma-chain), and an alpha-linked lactose (beta-chain) residue. From the central heptose (Hep-1), a beta(1-->4) linked lactose (alpha-chain), moiety is required although extensions to this residue appear unnecessary.      

Collective reactions of neostriatum (putamen) neurons to alternative behaviour in monkeys

Significant differences were found in collective unit activity of 6 neostriatum neurons associated with performance of either left- or right-sided task by monkeys: at the moment of decision-making regarding the direction of the movement, and after its completion, irrespective of correctness of the choice. The differences at the moment of the programme completion were significantly greater than at the moment of the decision-making.