Toxicity assessment of industrial effluents from S. Paulo state,Brazil, using short-term microbial assays

Microorganisms have demonstrated several attributes that make them attractive for use in quick screening of effluents and chemicals for toxicity. The aim of this study was to evaluate the acute toxicity and mutagenicity of industrial effluents from São Paulo State using short-term microbial bioassays. Samples of industrial effluents and receiving waters were analyzed for acute toxicity by the Microtox system, a motility test using Spirillum volutans, growth inhibition of Pseudomonas fluorescens, and dehydrogenase assay; for mutagenicity, these samples were analyzed by Salmonella typhimurium (Ames test), Escherichia coli WP₂, and Saccharomyces cerevisiae reversion mutation assays. Among the acute toxicity assays carried out in this study, the Microtox and S. volutans tests showed good sensitivity and general good agreement with the Daphnia similis assay, which demonstrates that these tests are potentially useful as toxicity indicators for the industrial effluents and receiving waters considered. In relation to mutagenicity assays, good results were obtained with the three methods tested. The detection of mutagens in the industrial effluents considered indicates that some constituents of these waste waters discharged in receiving waters can cause adverse biological effects and could be deleterious from a public health standpoint. The data of this research emphasize the importance of acute toxicity and mutagenicity assays as supplementary approaches for a rapid and efficient action in water pollution control, and for evaluation of potential toxic chemical effects.     

Case report: Liver function abnormalities in a severe case of hyperreactio luteinalis

Rare causes of liver dysfunction in pregnancy may pose a challenge to the consulting gastroenterologist or hepatologist from both the diagnostic and therapeutic standpoints. We describe here liver function abnormalities in a case of hyperreactio luteinalis with light and electron microscopic findings.     

Mounting and calibration of stairs on piezoelectric force platforms

To calculate the centre of pressure using piezoelectric force plates mounted on pads, no net tensile stresses may be imposed on the surface of the plate. This condition is violated when stairs are attached to the plates, unless the plates are preloaded. Typical shear forces encountered when climbing stairs were used to determine required preloads of approximately 16.4 N/cm step height. Vertical and horizontal loads were applied at known locations on the steps, and points of application were calculated. Deviations were within ± 3 mm. The effect of point of application inaccuracy on calculated joint moments is considerable. A 2 cm medial shift in the point of application resulted in calculated peak knee abduction/adduction moment errors of 35%.     

Blood serum levels of immunoglobulins among African children: Seasonal variations and ethnic factors (a study done in Lourenco-Marques among a group of 11-year olds) (author's transl)]

The blood titers of IgG, IgA and IgM and total proteins were determined in October 1971 (dry season) and again in April 1972 (wet season) among girls and boys belonging to 4 ethnic groups: White, Bantu, Indian, Mixed. Parasitic studies were also done. These studies indicate a rise of IgM among the girls and of IgA in both sexes from October 1971 to April 1972. The average IgM titer among the four groups is higher than the one found in the Occident. This is especially notable for the Bantu and the Mixed. The Indian levels exceeded, on the average, the White group's. The average IgG figures are only slightly higher than those found in the literature for Western populations. Genetic influences do not appear to explain the differences found between the ethnic groups. The role of environment is stressed, and parasitic influences are discussed.     

Platelet mobilization induced by PAF and its role in the thrombocytosis triggered by adrenaline in rats

The injection of PAF (6 micrograms/kg, i.v.) induced, in rats, haemoconcentration accompanied by an increase in the platelet number, as attested by the counts of platelets in blood samples diluted in formalin-free EDTA solution. This increase was significant at 15 min, peaked from 1 to 4 h and returned to basal levels 24 h after the lipid administration. The release of platelets induced by PAF was inhibited dose-dependently by specific PAF receptor antagonist such as WEB 2086 (0.5-2 mg/kg), BN 52021 and 48740 RP (5-25 mg/kg). Furthermore, platelet mobilization was clearly impaired in splenectomized animals stimulated by PAF, whereas thrombocytopenia and haemoconcentration by the same stimulus were intact. It was also noted that a second injection of PAF, 24 h after the initial stimulation with the lipid, failed to induce an increase in platelet counts, indicating autodesensitization. Desensitization to PAF or pretreatment with PAF antagonists clearly prevented the increase in the platelet counts after stimulation by adrenaline (15 micrograms/kg). These findings suggest that, in rats, PAF can induce release of platelets by a spleen-dependent mechanism and that this lipid may be relevant to the thrombocytosis triggered by adrenaline.