Resumo O presente estudo refere-se ao impacto do uso de agrotóxicos sobre a saúde humana no Submédio do Vale do São Francisco. Por meio de entrevistas objetivou-se analisar a influência dos condicionantes sociais, culturais e econômicos no processo saúde-doença dos trabalhadores expostos a agrotóxicos. Para a coleta de dados foram entrevistados 339 trabalhadores rurais de perímetros irrigados dos municípios de Juazeiro-BA e Petrolina-PE. Todos do sexo masculino, sendo 182 (53,7%) proprietários rurais e 157 (46,3%) empregados, predominando indivíduos entre 40 e 59 anos entre os proprietários e abaixo de 39 anos entre os trabalhadores. Mais de 50% apresentou baixo nível de escolaridade e 55,2% tinha rendimentos mensais menor ou igual a 2 salários mínimos. Muitos sabem da importância do uso de EPIs e da obrigatoriedade do receituário agronômico para a utilização e a compra de agrotóxicos, entretanto cerca de 40% não usam EPIs ou fazem uso de forma incompleta e 28,9% não apresentam receituário durante a compra. Mais de 9% dos participantes relataram casos de intoxicação, no entanto, menos de 7% procuraram atendimento especializado. Os trabalhadores sabem que o uso de agrotóxicos nas lavouras os expõem a situações de risco, mas essa informação não é suficiente para alterar a conduta no exercício laboral.

Recebido em 18/5/10; aceito em 1/2/11; publicado na web em 1/4/11 DIFFERENT STRATEGIES FOR CROSSLINKING OF CHITOSAN. One of the most important aspects of chitosan' derivatization depends on the crosslinking of their polymeric chains. This chemical strategy may confer new properties to those derivatives, which can be used to enhance their biotechnological applications. So far, this work aims to discuss some strategies related to the crosslinking of chitosan focusing on reagents, reaction mechanisms and properties/applications of the crosslinked derivatives in several fields of science.

Acetylcholinesterase (AChE) has an unquestionable importance to functioning of cholinergic synapses present in our central and peripheral nervous system, which makes this enzyme an attractive target for the development of new drugs. In this context, knowledge of methods that can be employed to assess the enzymatic activity of AChE is an important factor to the success of scientific research related to this enzyme. Thus, this paper initially deals with the AChE and molecules capable of inhibiting or reactivate this biological catalyst. Then, are explained the basics of the different methodologies used to determine the enzymatic activity of AChE, from the simple and inexpensive, to methods that require larger investments in reagents and equipment. With this review, the authors provide some alternatives to the researchers to conduct the experiments involving the determination of AChE activity, so that they can evaluate and choose the most appropriate method for their trials.

Background: Natural naphthoquinones have shown diversified biological activities including antibacterial, antifungal, antimalarial, and cytotoxic activities. However, they are also compounds with acute cytotoxicity, immunotoxicity, carcinogenesis, and cardio- and hepatotoxicity, then the modification at their redox center is an interesting strategy to overcome such harmful activity. Objective: In this study, four novel semisynthetic hydrazones, derived from the isomers α- and β-lapachones (α and β, respectively) and coupled with the drugs hydralazine (HDZ) and isoniazid (ACIL), were prepared, evaluated by electrochemical methods and assayed for anticancer activity. Method: The semisynthetic hydrazones were obtained and had their molecular structures established by NMR, IR, and MS. Anticancer activity was evaluated by cell viability determined by reduction of 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT). The electrochemical studies, mainly cyclic voltammetry, were performed, in aprotic and protic media. Result: The study showed that the compounds 2, 3, and 4 were active against at least one of the cancer cell lines evaluated, being compounds 3 and 4 the most cytotoxic. Toward HL-60 cells, compound 3 was 20x more active than β-lapachone, and 3x more cytotoxic than doxorubicin. Furthermore, 3 showed an SI value of 39.62 for HL-60 cells. Compound 4 was active against all cancer cells tested, with IC50 values in the range 2.90–12.40 μM. Electrochemical studies revealed a profile typical of self-protonation and reductive cleavage, dependent on the supporting electrolyte. Conclusion: These results therefore indicate that compounds 3 and 4 are strong candidates as prototypes of new antineoplastic drugs.