RESUMO
A new alternative approach for the determination of molybdenum in steel is proposed, using adsorptive stripping voltammetry (AdSV). The determinations are performed in a homogeneous ternary solvent system (HTSS) composed of N,N-dimethylformamide, ethanol and water, with alpha-benzoinoxime (alpha BO) as the complexing agent and a sodium acetate-acetic acid buffer as the support electrolyte. The HTSS composition was optimized by mixture design modelling. The AdSV measurements were performed in the differential pulse mode using an accumulation potential of -1050 mV. Under these optimized experimental conditions, the Mo(VI)-alpha BO reduction current peak potential is observed at potentials near -1250 mV, much lower than those usually reported, and the calibration plot follows the polynomial equation I = 0.359 + 0.265 [CMo(VI)] - 0.015 [CMo(IV)]2 (r2 = 0.997), for Mo concentrations up to 10.0 micrograms L-1. There is a linear range in this calibration plot for Mo(VI) concentrations up to 0.20 microgram L-1, defined by the equation I = 0.353 + 0.385 [CMo(VI)] (r2 = 0.980). In both cases, I is the absolute value for the current in microA and CMo(VI) is the concentration of Mo in microgram L-1. The detection limit for this linear concentration range was estimated as 20 pg L-1. A RSD of 0.43% is associated with the signals at a Mo(VI) level of 0.72 microgram L-1. From the common method-interfering species tested, only iron at Fe/Mo(VI) ratios above 500 and vanadium and tungsten at M/Mo(VI) ratios above 100 appear to affect the analytical response significantly. Phosphorous may also reduce the analytical signal at P/Mo(VI) ratios above 100, due to the formation of the competitive P-Mo complex. The suggested routine procedure was tested by analyzing four stainless steel samples and the results compared well with the ICP-AES measurements. The higher sensitivity of this method permits direct determination of Mo(VI) in steels, eliminating the need of analyte concentration or separation steps in the sample processing procedure.
RESUMO
Epidemiological aspects of malaria in the State of S. Paulo, Brazil, based on the cases motified between 1983 and 1992 are presented. In the period 20,200 cases, of which 65.7% presented Plasmodium vivax (P.v.) and 27.3% P. falciparum (P.f.), were confirmed. No differences as between the years was observed. No differences in the distribution by sex (85.4% male) or age (63.6% whit ages between 20 and 39 years) were noted. The epidemiological investigations demonstrated that in 2.0% the transmission of malaria has occurred in two different areas of the State of S. Paulo. One of these areas is covered with Atlantic forest where malaria is considered endemic, with a predominance of P. vivax and low parasitaemias associated with Kerteszia. The other area is the Paulista plateau, where Nyssorhynchus and patients with imported malaria were responsible for pochets P.V. and P.f. It was noted that 91.6% of the cases came from other regions of the country, 89.0% of them from Rondomia, Mato Grosso and Pará. The increase in the number of cases from Mato Grosso, corresponding to 51.7% of the total in 1992, was verified over this ten-year period. Malaria induced by blood transfusion and among drug users represented 27 and 58 cases, respectively. The lethality rate was 5.0/1,000 patients and occurred among patients with first time and late diagnosis of P. falciparum malaria. The study of this information adds its contributions for malaria surveillance.
Assuntos
Malária/epidemiologia , Adulto , Fatores Etários , Brasil/epidemiologia , Feminino , Humanos , Malária/transmissão , Masculino , Fatores SexuaisRESUMO
A review is presented of 58 induced malaria cases diagnosed in the São Paulo State, from January 1983 to July 1990. These cases represent 0.3% of the malaria notifications. The parameters sex, age, parasitaemia, clinical symptoms, clinical course and mean time interval between disease onset and diagnosis were studied in 25 blood-transmitted cases and 28 related to sharing needles. Plasmodium vivax was diagnosed in 79.4% and in 5.6% Plasmodium vivax and Plasmodium falciparum were seen. Lower mean age (p < 0.005) in intravenous drug users when compared in the blood-transmitted group were observed. The former also had a mean time interval between disease onset and diagnosis (33.6 days) and patients with blood-transmitted disease (20.6 days). No statistical significant differences were observed (p > 0.10). Even though few induced malaria cases have been diagnosed in São Paulo, State, and considering that blood-transmitted malaria is now under control, the occurrence of malaria due to sharing needles among intravenous drug users should be regarded as a risk for the reintroduction of the disease in malaria--free areas of São Paulo State.
Assuntos
Malária Falciparum/transmissão , Malária Vivax/transmissão , Adulto , Brasil , Feminino , Humanos , Masculino , Ferimentos Penetrantes Produzidos por Agulha/complicações , Reação TransfusionalRESUMO
Cases of induced malaria have been notified in S. Paulo State, Brazil, in recent years. At the same time the number of cases imported from endemic regions of Brazil has been increasing. One case of induced malaria by Plasmodium vivax was registered in Presidente Prudente, located in the west of the State, in 1988 and a further eleven cases in 1989. This city is considered to be one of the main transit ports for people who come into the State from the Amazonian region. The patients declared that they had not been to any possible transmission area of malaria. All of them had, however, taken cocaine, sharing the same contaminated needle and syringe. Previously, one person with imported malaria was detected, who had transmitted the disease to the first case in 1988 and also to a further group of 3 people in 1989. One of these three latter cases then transmitted the disease to two other people. As the group of people continued to use the drug among themselves, 2 new cases arose. Afterwards, they re-infected themselves again (one of the was re-infected twice). The test for Human Immunodeficiency Virus was positive for 5 individuals, of whom one had a negative result and 2 others did not undergo the test. This information is discussed within the present context.
Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , Malária/complicações , Abuso de Substâncias por Via Intravenosa/complicações , Síndrome da Imunodeficiência Adquirida/epidemiologia , Adolescente , Adulto , Animais , Brasil/epidemiologia , Soropositividade para HIV , Humanos , Malária/epidemiologia , Masculino , Plasmodium vivax/isolamento & purificaçãoRESUMO
With a view to discovering the social and economic characteristics of people from endemic malarial areas of Brazil, 566 suspected malaria cases were studied at the S. Paulo City Metropolitan Region Malaria Laboratory. Data were obtained by means of the application of standardized questionnaires over the period from November 1986 to June 1987 to individuals with as history of transit to Brazil's endemic malarial region. Of the population studied, 345 (61.0%) lived in the endemic area; 479 (84.6%) were males, 513 (90.7%) were between 15 and 55 years old and 307 (54.2%) presented positive plasmodium haemoscopia. The analysis by educational level indicated that 486 (85.9%) had primary or secondary education; 109 (19.3%) worked in mineral extraction; 74 (13.2%) were farmers, and 46 (8.1%) were related to terrestrial transportation activities. With respect, to knowledge of the disease, 384 (67.8%) had at least 1 bout of malaria before and 491 (86.8%) associated the disease with the presence of the vector. Of the 221 residents in S. Paulo, 207 (93.7%), as well as 336 (97.4%) of those residing in the endemic area already know of the risks of infection prior to travelling through the area of transmission. The interval between the first symptoms and the seeking for medical care varied from 0 to 3 days in 386 cases (68.2%). The frequencies of the variables studied analysed according to the haemoscopic result and the place of residence, were statistically significant.
Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Malária/epidemiologia , Brasil/epidemiologia , Emigração e Imigração , Feminino , Humanos , Malária/diagnóstico , Malária/transmissão , Masculino , Fatores SocioeconômicosRESUMO
A rapid method of determining zinc and iron in food by flame atomic-absorption spectrophotometry with slurry nebulization into an air-acetylene flame has been developed. A V-groove, clog-free Babington-type nebulizer, coupled to a single-line flow-injection analysis (FIA) system, was employed to introduce the slurry into the spray chamber. Under the FIA conditions described, an injection frequency of 120/hr is possible, with negligible carry-over and memory effects. The calibration graphs were obtained by using various concentrations (up to 0.1 g/ml) of white bean homogenate as standards, rather than solutions. The method has been applied to various kinds of foods, including grains, vegetables, fruits and sausage. Homogenization of semi-prepared samples to form slurries took only 4 min. Relative deviations between results by the slurry and solution methods for both elements averaged 2-3%. Detection limits by the slurry method were 0.3 mug/ml Zn and 0.6 mug/ml Fe.
RESUMO
This report summarizes the surgical experience and early results obtained at four surgical centers in the northeast and south of Brazil. From December 1977 to September 1986, 95 operations were performed on 93 patients, ages 11-59. Bilateral lesions occurred in 42 patients, right lesions in 39, and left lesions in 12. Ventricular decortication and removal of thrombi were performed in all. In right-sided lesions, the tricuspid valve was substituted by a bioprosthesis in 34 cases, and substituted by a tilting disk valve in 1 case. In 4 patients, the valve could be preserved. The left-sided lesions led to valve substition by a bioprosthesis in 11 cases, and preservation of the valve in 1. The bilateral lesions needed bioprosthesis in the mitral position in 37 patients, and a disk valve in 2. In these 39 instances, the valvular procedure was insertion of a tricuspid bioprosthesis. Three tricuspid and three mitral plasties were performed. The overall mortality was 20% (26.2% for bilateral lesions, 14.6% for the right-sided lesions, and 20% for the left-sided lesions). The main cause of death was low cardiac output. Aside from a variable degree of right and left ventricular failure, many other non-fatal complications clouded the postoperative course. Complete AV blocks occurred in 10 cases, with the need for permanent pacing in 7 survivors. The mortality and morbidity in the present series is in keeping with the results reported in current literature. Regarding the advanced stage of their patients' disease, the authors agree with the recommendation for earlier surgical intervention.