Socio-medical intervention in occupational health: benzenism in Brazil.

This review describes the authors' experience with 2,000 cases of benzene poisoning reported between 1983 and 1995 in Cubatão, an industrial section of São Paulo, Brazil, investigated through the integration of epidemiology and clinical research. Conflicting economic interests were reflected in disputes about medical criteria for evaluation of poisoned workers, about proper means of conducting workplace hygiene evaluations, about benzene exposure standards, and about compensation for chronic bone-marrow damage.

[Evolution of schistosomiasis endemicity in the Zona da Mata Sul, Pernambuco State, Brazil. Epidemiology and current situation: under control or out of control?]. / Evolução da esquistossomose na Zona da Mata Sul de Pernambuco. Epidemiologia e situação atual: controle ou descontrole?

In order to assess the present situation of schistosomiasis in the Zona da Mata Sul, Pernambuco State, Brazil, a study was conducted in the following phases: origin, historical and temporal evolution, and basic determinants of this health/disease process; critical assessment of comprehensive intervention programs implemented by the State in the region since 1970; and a case study in 17 counties, representing 1,424 communities and 485,200 inhabitants, and Brazil's second most endemic region based on prevalence rates for schistosomiasis. Temporal series over a 14-year period were used to analyze results of intervention programs. Conclusions were: a) current positivity rates are higher than those observed in the early 1980s; b) the programs' strategy focused almost exclusively on mass treatment, thus allowing for reinfestation and occurrence of new cases; c) proposals such as the PCDEN (Program for Control of Endemic Diseases in the Northeast) aimed at decentralization to the municipal level in the 1990s were not effectively implemented, helping to leave this persistent endemic out of control.

[An evolutionary study of mucosal leishmaniasis (a 7- to 17-year follow-up) due to Leishmania (Viannia) braziliensis in Tres Braços, Bahia]. / Estudo evolutivo da leishmaniose mucosa (7 a 17 anos de seguimento) causada por Leishmania (Viannia) braziliensis em Três Braços, Bahia.

Seventy seven (68%) patients with mucosal leishmaniasis recorded during the period 1976-1986 in the region of Três Braços, Bahia were traced and re-evaluated clinically, diagnostically and therapeutically. Sixty-five patients were alive. The families of 12 dead patients were interviewed about probable cause of death. The 65 patients had a fresh clinical examination supplemented when necessary by a skilled ENT examination. All had a titre of circulating immunofluorescent antibodies estimated at the time. Eight patients with active mucosal lesions had triturated biopsies which were cultivated in NNN medium and inoculated in hamsters to attempt to recover Leishmania. The isolates were identified by monoclonal antibodies as Leishmania (Viannia) braziliensis. Fifty-six (86%) patients were judged clinically cured. Nine (13%) had active lesions. Of the 12 patients who died 5 (41%) had no signs of activity at death. Mucosal leishmaniasis was thought to be the direct cause of death in 3 patients. The field treatment programme at Três Braços has managed to clinically cure 61 patients (79%) during 17 years. Follow-up periods were a mean of 10 years (range 7-17).

Renal involvement in visceral leishmaniasis.

In a prospective study of 50 patients with visceral leishmaniasis, laboratory abnormalities suggestive of renal involvement were not infrequent. Proteinuria and/or microscopic hematuria or pyuria were observed in 51% of such cases. Twenty-four hour urinary protein excretion was elevated in 57% of patients in all cases below 1g/24 hours. An abnormal acid-load test was demonstrated in 12 of 18 patients studied before therapy of the parasitic infection with N-methyl-glucamine. Of interest was the demonstration of tubulo-interstitial involvement in the renal histology of all seven patients studied; also, in five of seven patients there was a proliferative glomerulonephritis, usually mild, on histologic examination. In general, there was a tendency to subsidence of abnormal laboratory findings within one month after specific therapy. Renal involvement in visceral leishmaniasis was mild and seemed to revert with the cure of the leishmanial infection.

Cefamandole treatment of Salmonella bacteremia.

The efficacy of cefamandole in the treatment of 19 patients with salmonella bacteremia was evaluated. Although all of the salmonella strains isolated were highly susceptible to cefamandole in vitro, a therapeutic failure was observed in 7 (36.8%) of the 19 patients.

FM-AM conversion by material dispersion in an optical fiber.

We show that material and guide dispersion may be used effectively in an optical fiber to convert an FM signal to an AM signal after it traverses a certain minimum fiber length. This length depends on material and modal dispersion of the guide. An upper limit to the fiber length is established and is shown to be related to laser linewidth. We also discuss laser-mode selection and conversion in multimode fibers.