Pharmacology and toxicology of diphenyl diselenide in several biological models

The pharmacology of synthetic organoselenium compounds indicates that they can be used as antioxidants, enzyme inhibitors, neuroprotectors, anti-tumor and anti-infectious agents, and immunomodulators. In this review, we focus on the effects of diphenyl diselenide (DPDS) in various biological model organisms. DPDS possesses antioxidant activity, confirmed in several in vitro and in vivo systems, and thus has a protective effect against hepatic, renal and gastric injuries, in addition to its neuroprotective activity. The activity of the compound on the central nervous system has been studied since DPDS has lipophilic characteristics, increasing adenylyl cyclase activity and inhibiting glutamate and MK-801 binding to rat synaptic membranes. Systemic administration facilitates the formation of long-term object recognition memory in mice and has a protective effect against brain ischemia and on reserpine-induced orofacial dyskinesia in rats. On the other hand, DPDS may be toxic, mainly because of its interaction with thiol groups. In the yeast Saccharomyces cerevisiae, the molecule acts as a pro-oxidant by depleting free glutathione. Administration to mice during cadmium intoxication has the opposite effect, reducing oxidative stress in various tissues. DPDS is a potent inhibitor of d-aminolevulinate dehydratase and chronic exposure to high doses of this compound has central effects on mouse brain, as well as liver and renal toxicity. Genotoxicity of this compound has been assessed in bacteria, haploid and diploid yeast and in a tumor cell line.

Análise de traços de sulfato e cloreto em material particulado atmosférico através de técnicas eletroanalíticas / Determination of traces of sulfates and chlorides in atmospheric particulate material by electroanalytical methods

No presente trabalho foi desenvolvida metodologia para determinaçäo de traços de sulfatos em material particulado atmosférico. Foi também estudada a viabilidade de utilizaçäo da titulaçäo potenciométrica com AgNO3 na determinaçäo de cloretos no mesmo tipo de matriz ambiental. Comprovou-se que pela utilizaçäo deste método gráfico, pode-se chegar à determinaçäo de até 10 M de cloretos, quando se emprega o método da adiçäo prévia de padräo, com erro relativo de l5,1%. Empregando-se esse método foram determinados íons cloreto em material particulado atmosférico coletado na regiäo da área metropolitana de Säo Paulo, na faixa de 0,5 a 2,0 ug/m3, com coeficiente de variaçäo de 20 e 8% respectivamente, para a menor e a maior concentraçäo.

Utilizaçäo do metanol como componente alternativo da mistura combustível para veículos auto-motores: parecer técnico / Use of methanol as an alternative component of the misture for motor fuels

Foi feita uma análise para orientar a determinaçäo dos riscos a saúde e medidas de controle necessárias para a utilizaçäo da nova mistura combustível no Brasil