Psoralen/UVA treatment and chromosomes

Summary Treatment of human lymphocytes in vitro with trimethylpsoralen or 8-methoxypsoralen and UVA irradiation (PUVA) induced chromosome damage, mainly constrictions and gaps, but also breaks and exchanges, and increased the frequency of sister chromatid exchange (SCE). The localization of the chromosome aberrations was nonrandom. The coincidence of many PUVA hits with mercaptoenthanol hits suggests that PUVA may have other targets in the cell than the DNA, perhaps the folding proteins of the chromosomes and the nuclear membrane/chromatin attachment organelles.Caffeine increased in a synergistic way the chromosome aberration yield if added after PUVA treatment, but there was no effect when caffeine was present before and during PUVA treatment. The SCE frequency was increased in the presence of caffeine.     

Comparison of the in vivo clearance of des-AA and des-AABB rat fibrin monomers prepared by different methods

Solubilization of fibrin monomers (Fm's) is usually performed with dilute acetic acid, urea or sodium bromide. These solvents can affect the biological properties of Fm's. Therefore we describe a new method to keep Fm's in solution, under milder conditions i.e. by generating them in Dcate solutions and avoiding non-physiological conditions. The in vivo behaviour of iodinated rat Fm's injected in rats and prepared by this new method was compared with that of Fm's dissolved in acetic acid, urea or sodium bromide.Fm's prepared in Dcate solutions accumulate rapidly, within 10 minutes after injection, in all organs tested, predominantly in kidney, liver and lung, probably by interaction with endothelial cells. The blood radioactivity remains nearly constant during the first 90 minutes and decreases thereafter exponentially. Fm's dissolved in sodium bromide behave similarly. However, Fm's dissolved in acetic acid or urea behave differently and do not accumulate in organs. This suggests that Fm's loose their capability to accumulate in organs and probably to interact with endothelial cells when they have been dissolved in acetic acid or urea.The slow exponential clearance phase does not differ significantly between the various Fm's and their $\text{T}\text{1}\text{2'S}$ are estimated to lie between 5 and 7 hours.     

Foliicole Flechten aus der Kolchis (West-Transkaukasien,UdSSR)

This paper deals with 19 species of foliicolous lichens collected in the summer months of 1977 to 1980 during several excursions to the vicinity of the spas Sochi, Gagra and Sukhumi on the east shores of the Black Sea (part of the Colchis). Some new taxa and one new combination are proposed:Raciborskiella minor Vězda (sp. n.),Porina colchica Vězda (sp. n.),Gyalectidium caucasicum (Elenk. etWoronich.)Vězda (comb. n.),G. colchicum Vězda (sp. n.),Bacidia vasakii Vězda (sp. n.). Taxonomical, ecological and plant geographical notes to all species are given.     

Toxicological evaluation of agromet (Metalaxyl) preparation.

A complex toxicological study was carried out in relation to the hygienic standardization of the fungicide preparation Ridomil, whose forthcoming production in this country will be under the name Metalaxyl. The study was performed on sexually mature white rats of both sexes, at oral, dermal and inhalation exposure, acute, subacute and chronic experiments, according to the Bulgarian State Standard. Besides the routine toxicological studies were carried also studies for establishing the long-term effects of the preparation (gonadotropic, embryotoxic and teratogenic, cardiovascular). The results from the study permitted the Agromet preparation to be put in III class--moderately toxic according to limiting index LD50 oral. On the basis of data from the authors study on the general toxicity and long-term effects of Metalaxyl a temporary MAC 4 mg/m3 was proposed.     

Ostracoden von Hawaii,insbesondere aus dem marinen Interstitial

The present paper deals with ostracods collected by H. Kunz during October and November 1979 on the Hawaiian Islands (Big Island, Maui and Kauai). 26 species were found, nine species are described, two were already known to science, 15 remain in open nomenclature. Although some of the new species are represented only by a single specimen, the morphologic characters permit to distinguish them from other species of the genus. The ostracods of the Hawaiian Islands are very imperfectly known.      

The human rhabdomyosarcoma cell line A204 lays down a highly insoluble matrix composed mainly of alpha 1 type-XI and alpha 2 type-V collagen chains.

The biosynthesis of collagen by the A204 cell line was examined using polyclonal antibodies raised against collagen type V and type XI. The study of the pepsin-digested collagen showed that it is composed mainly of alpha 1(XI) and alpha 2(V) collagen chains in an apparent 2:1 ratio, suggesting the formation of heterotypic molecules [alpha 1(XI)]2 alpha 2(V). The existence of this chain stoichiometry was further demonstrated by immunoprecipitation of the molecule with an antibody recognizing alpha 2(V) but not alpha 1(XI) collagen chains. Electron microscopy analyses of 24-h cultures showed that this matrix is composed of thin fibrils, that can be decorated with immunogold-labelled anti-(type-V collagen) IgG, but not with anti-(type-XI collagen) IgG. The collagen matrix laid down by A204 cells is highly insoluble. In the presence of beta-aminopropionitrile, an inhibitor of lysyl oxidase, only a small proportion of intact collagen could be extracted without proteolytic treatment. Immunoblotting of intact medium collagen from cultures performed in the presence of beta-aminopropionitrile showed four distinct bands with each antibody. The migration of the bands, stained with anti-(type-V collagen) IgG, had apparent molecular masses of 127, 149, 161 and 198 kDa (compared to globular standards) while the bands stained with anti-(type-XI collagen) IgG had apparent masses of 145, 182, 207 and 225 kDa. These data indicate that type-V and type-XI collagen chains can assemble in heterotypic isoforms. In this system, the synthesized isoforms are able to aggregate into a highly cohesive matrix and they undergo a proteolytic processing closely similar to that of other fibrillar collagens.     

Amyloidogenicity of beta A4 and beta A4-bearing amyloid protein precursor fragments by metal-catalyzed oxidation.

Previously we have shown that the COOH-terminal 100 residues (A4CT) of the amyloid protein precursor (APP), which carry the sequence of the amyloid beta A4 protein of Alzheimer's disease at N-terminal position, form highly insoluble aggregates if expressed in the rabbit reticulocyte lysate and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Dyrks, T., Weidemann, A., Multhaup, G., Salbaum, J.M., Lemaire, H.-G., Kang, J., Müller-Hill, B., Masters, C. L., and Beyreuther, K. (1988) EMBO J. 7, 949-957). Here we report that aggregation of this COOH-terminal APP fragment A4CT and also of beta A4 itself depends on additional factors. In contrast to the reticulocyte expression system, expression of A4CT and beta A4 in the wheat germ expression system resulted in only monomeric forms. We have identified the factors which are capable of transforming both soluble A4CT and beta A4 into insoluble and aggregating molecules. Monomeric A4CT or beta A4 expressed in the wheat germ lysate could be transformed into aggregating molecules by the addition of metal-catalyzed oxidation systems. The addition of radical scavengers such as ascorbic acid, trolox, and amino acids prevented the aggregation process induced by the radical initiators. Thus, the aggregation of amyloidogenic APP fragments if analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis requires amino acid oxidation and protein cross-linking induced by radical generation systems.