Leather waste--potential threat to human health, and a new technology of its treatment.

In this paper, the authors deal with the problem of processing various types of waste generated by leather industry, with special emphasis to chrome-tanned waste. The agent that makes this waste potentially hazardous is hexavalent chromium. Its compounds can have negative effects on human health and some CrVI salts are considered carcinogens. The authors present the risks of spontaneous oxidization of CrIII to CrVI in the open-air dumps as well as the possible risks of wearing bad quality shoes, in which the chromium content is not controlled. There are several ways of handling primary leather waste, but no satisfactory technology has been developed for the secondary waste (manipulation waste, e.g. leather scraps and used leather products). In this contribution, a new three-step hybrid technology of processing manipulation waste is presented and tested under laboratory, pilot-scale and industrial conditions. The filtrate can be used as a good quality NPK fertilizer. The solid product, titanium-chromium sludge, can serve as an inorganic pigment in glass and ceramic industry. Further, the authors propose selective collection of used leather products (e.g. old shoes), the hydrolysable parts of which can be also processed by the new hybrid technology.

Development of a new Sindbis virus transducing system and its characterization in three Culicine mosquitoes and two Lepidopteran species.

Alphavirus transducing systems (ATSs) are alphavirus-based tools for expressing genes in insects. Here we describe an ATS (5'dsMRE16ic) based entirely on Sindbis MRE16 virus. GFP expression was used to characterize alimentary tract infections and dissemination in three Culicine and two Lepidopteran species. Following per os infection, 5'dsMRE16ic-EGFP efficiently infected Aedes aegypti and Culex tritaeniorhynchus, but not Culex pipiens pipiens. Ae. aegypti clearly showed accumulation of green fluorescent protein (GFP) in the posterior midgut and foregut/midgut junction within 2-3 days postinfection. Following parenteral infection of larvae, Bombyx mori had extensive GFP expression in larvae and adults, but Manduca sexta larvae were mostly resistant. 5'dsMRE16ic should be a valuable tool for gene expression in several important insect species that are otherwise difficult to manipulate genetically.

Helminth parasites of cats from the Vientiane province, Laos, as indicators of the occurrence of causative agents of human parasitoses.

A total of 55 domestic cats (Felis catus f. domestica) and one wild (Bengal) cat (Prionaluirus bengalensis) from the Vientiane Province, central Laos, were examined for helminth parasites with emphasis given to potential human parasites. The following species were found (parasites infective to man marked with an asterisk): Opisthorchis viverrini, Haplorchis pumilio, H. taichui, H. yokogawai, Stellantchasmus falcatus (Digenea); Spirometra sp., Dipylidium caninum, Taenia taeniaeformis (Cestoda); Capillariidae gen. sp., Toxocara canis, T. cali, Ancylostoma ceylanicum, A. tubaeforme, Gnathostoma spinigerum, Physaloptera preputialis (Nematoda); and Oncicola sp. (Acanthocephala). This study demonstrated that examination of cats may provide useful data on the occurrence of helminths which are potential causative agents of human diseases.

Changes of E-cadherin and beta-catenin levels during induced differentiation of colorectal carcinoma cells.

Following the finding of a great increase in cell-cell adhesion in several colorectal carcinoma cell lines after induced differentiation, the expression of E-cadherin-catenin complexes was analyzed. The sensitivity of cell lines to the differentiation induced by sodium butyrate differed. Nevertheless, all cells growing for 5 days in the medium containing 2 mM sodium butyrate changed their morphology and adherent properties. The expression of E-cadherin and catenins participating in its function were analyzed. A significant increase in E-cadherin level after butyrate treatment was found in HT29 and LS174T cell lines only. However, a high decrease in beta-catenin level was detected in all cell lines treated with butyrate. Further analysis showed regulation of beta-catenin at the level of mRNA.