Biomedical subjects
Publications and source records attributed to M G Pereira.
A procedure to obtain endosperm protein extracts was standardized. After confirming the enrichment with nuclear proteins by immunodetection, the protein profiles of extracts from different seed development stages were compared by SDS-PAGE that showed the existence of several differentially expressed proteins.
A lectin isolated from the red alga Solieria filiformis was evaluated for its effect on the growth of 8 gram-negative and 3 gram-positive bacteria cultivated in liquid medium (three independent experiments/bacterium). The lectin (500 microg/mL) stimulated the growth of the gram-positive species Bacillus cereus and inhibited the growth of the gram-negative species Serratia marcescens, Salmonella typhi, Klebsiella pneumoniae, Enterobacter aerogenes, Proteus sp, and Pseudomonas aeruginosa at 1000 microg/mL but the lectin (10-1000 microg/mL) had no effect on the growth of the gram-positive bacteria Staphylococcus aureus and B. subtilis, or on the gram-negative bacteria Escherichia coli and Salmonella typhimurium. The purified lectin significantly reduced the cell density of gram-negative bacteria, although no changes in growth phases (log, exponential and of decline) were observed. It is possible that the interaction of S. filiformis lectin with the cell surface receptors of gram-negative bacteria promotes alterations in the flow of nutrients, which would explain the bacteriostatic effect. Growth stimulation of the gram-positive bacterium B. cereus was more marked in the presence of the lectin at a concentration of 1000 microg/mL. The stimulation of the growth of B. cereus was not observed when the lectin was previously incubated with mannan (125 microg/mL), its hapten. Thus, we suggest the involvement of the binding site of the lectin in this effect. The present study reports the first data on the inhibition and stimulation of pathogenic bacterial cells by marine alga lectins.
Previous studies have shown that women are more emotionally expressive than men. It is unclear, however, if women are also more susceptible to the emotional modulation of behavior imposed by an affective stimulus. To investigate this issue, we devised a task in which female subjects performed six sequential trials of visual target detection following the presentation of emotional (mutilation and erotic) or neutral pictures (domestic utensils and objects) and compared the data obtained in the present study with those described in a previous study with male subjects. The experiment consisted of three blocks of 24 pictures and each block had an approximate duration of 4 min. Our sample consisted of 36 subjects (age range: 18 to 26 years) and each subject performed all blocks. Trials following the presentation of mutilation pictures (283 ms) had significantly slower reaction times than those following neutral (270 ms) pictures. None of the trials in the "pleasant block" (271 ms) was significantly different from those in the "neutral block". The increase in reaction time observed in the unpleasant block may be related in part to the activation of motivational systems leading to an avoidance behavior. The interference effect observed in this study was similar to the pattern previously described for men. Thus, although women may be more emotionally expressive, they were not more reactive to aversive stimuli than men, as measured by emotional interference in a simple reaction time task.
We study time series of x-ray sources of 129 stellar binary systems present in the public data collected by the instrument All Sky Monitor on board of the satellite Rossi X-Ray Timing Explorer. The light time series was analyzed by applying detrended fluctuation analysis to estimate the long-range power-law correlation exponents alpha. The scaling exponent was calculated for all systems and its value indicated a signature of each kind of system, i.e., whether flare takes place (with alpha=1.22) or not (with alpha=0.64). As a consequence, our results may identify the stability of the systems from the scaling exponent alpha value, for instance, if alpha approximately 0.5 (white noise) the system is stable and unstable when alpha not equal to 0.5 (long-range power-law correlation).
The State of Minas Gerais represents one of Brazil's most outstanding mining resources. The contamination of river water from kaolin processing activities may be harmful to people in the way of slow but chronic poisoning. On the other hand, the discharge of untreated or inadequately treated domestic sewage into aquatic environments can also cause deleterious effects to the health. However, no reliable figures are available for pollutant occurrences in river water. This draws attention to the very precarious situation that exists with respect to pollution by organic and inorganic toxic wastes, especially with respect to humans and fauna in all its expressions. Thus, with the purpose of establishing a preliminary report to trace out industrialisation outcomes, samples of river water, vegetation and fish were collected and analysed to detect pollutant inputs. The concentration of metals was determined in suspended particle, vegetation and fish, while those of nitrite, nitrate, phosphate and chloride were determined in river water samples. The concentration of dissolved oxygen (DO) was measured in river water at the time of collection. Chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were also determined. Metal inputs in the samples analysed appeared to be related to effluent discharges into the rivers. The suspended particles showed high concentrations (in mg kg(-1)) of zinc (62 600) and aluminium (559 000), while vegetation samples collected near rivers were heavily contaminated with iron (7680). The fishes examined were contaminated with chromium (1.5 mg kg(-1)). In general, the concentrations of nitrite, nitrate, chloride, phosphate and BOD in river water were lower than the maximum values established by the Brazilian Environmental Standards.
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OBJECTIVE: To evaluate the association of herd demographics, parturition variables, stocking rate, and rotational grazing practices with the probability of fecal shedding of Cryptosporidium parvum from beef cow-calf herds in California. DESIGN: Cross-sectional study. SAMPLE POPULATION: 38 beef cow-calf operations. PROCEDURE: Fecal specimens were collected and examined for C parvum oocysts, using immunofluorescent microscopy. Association between various demographic and management factors and the probability of shedding C parvum were statistically evaluated. RESULTS: Adjusted for age and month of collection of a fecal sample, cattle from herds with a high number of young calves (< or = 2 months old) on the day of sample collection, a high stocking rate (No. of cattle/acre/mo), or a longer calving season were more likely to shed C parvum oocysts, compared with cattle from herds with fewer young calves, a lower stocking rate, or a shorter calving season. Cattle from herds with a higher number of older calves (> 2 months old) on the day of sample collection were less likely to shed C parvum oocysts, compared with cattle from herds with fewer older calves. Using our multivariate model, rotational grazing systems or season of onset of calving were not associated with shedding status for C parvum oocysts. CONCLUSIONS AND CLINICAL RELEVANCE: Reproductive management that would result in a shorter calving season and use of a lower stocking rate for cattle may be associated with reduced risk of C parvum shedding. Intensive rotational grazing systems and time of year for onset of calving season apparently have little effect on reducing prevalence of oocyst shedding.
The kappa coefficient has been the measurement preferred by epidemiologists for reliability studies. Various articles have demonstrated that the use of the kappa coefficient may have some undesirable features in certain contexts. Recently, methodologies using an ordinal scale for the modelling of interobserver agreement have been developed as an alternative to kappa. To show that there is a class of log-linear statistical models that when analyzed sequentially can be used to rate the patterns of agreement and disagreement. Using data on the comparability of primary and proxy respondent reports with respect to the frequency of alcoholic consumption and its correlation to coronary diseases a nested set of log-linear models was adjusted to find the "best" model. Computed odds ratios to determine the measure of agreement were also computed. The weight kappa was equal 0.685 with 95% CI (0.638-0.732) showing a good agreement. But it does not give any information about the structure of the agreement and disagreement. Among the sequence of models analyzed, the one with the best adjustment showed an agreement estimated at 0.4454 with 95% CI (0.1300-0.7608) and an association estimated at 1.3309 with 95% CI (0.9649-1.6978). The measure tau for adjacent categories was 9.2 with 95% CI (6.0-14.2). Thus, evidence shows that the observers tended to rate many phenomena similarly. Furthermore, high (or low) ratings made by primary respondents tended to be associated with high (or low) ratings made by the proxy respondents. Log-linear models can give us a more informative and more complete analysis with respect to the rating of matched pairs of observers than that given by kappa. In conclusion, the indiscriminate use of kappa as the only agreement index must be questioned. The appendix demonstrates how to use PROC GENMOD in SAS to fit these models.
Populations of feral pigs (Sus scrofa) may serve as an environmental reservoir of Cryptosporidium parvum oocysts and Giardia sp. cysts for source water. We conducted a cross-sectional study to determine the prevalence of and associated demographic and environmental risk factors for the shedding of C. parvum oocysts and Giardia sp. cysts. Feral pigs were either live-trapped or dispatched from 10 populations located along the coastal mountains of western California, and fecal samples were obtained for immunofluorescence detection of C. parvum oocysts and Giardia sp. cysts. We found that 12 (5.4%) and 17 (7.6%) of 221 feral pigs were shedding C. parvum oocysts and Giardia sp. cysts, respectively. The pig's sex and body condition and the presence of cattle were not associated with the probability of the shedding of C. parvum oocysts. However, younger pigs (< or = 8 months) and pigs from high-density populations (> 2.0 feral pigs/km2) were significantly more likely to shed oocysts compared to older pigs (> 8 months) and pigs from low-density populations (< or = 1.9 feral pigs/km2). In contrast, none of these demographic and environmental variables were associated with the probability of the shedding of Giardia sp. cysts among feral pigs. These results suggest that given the propensity for feral pigs to focus their activity in riparian areas, feral pigs may serve as a source of protozoal contamination for surface water.
Several previous studies in industrialized countries have linked both parents' smoking and low-socio-economic status with cigarette smoking in high school students. The purpose of the present study was to examine the association of parental smoking habits and family income with cigarette smoking by Brazilian students enrolled in an agricultural high school, in a developing area. As the study findings differ, additional studies are necessary to evaluate the differences in behaviour between students from developed and less developed countries.
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In a 20% random sample of University of Brasilia medical students no association was found between student and parental smoking behaviour. A low prevalence of habitual smoking (14.0%) and a low mean daily cigarette consumption (8.9 cigarettes per smoker, per day) characterized this population.
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This paper examines the association between serum protein levels and infection with Trypanosoma cruzi in a region of Central Brazil. 148 people 6 to 78 years of age, were included in this study. There were no statistically significant difference in albumin levels between those with positive T. cruzi serology (2.94 +/- 0.74 g/100 ml) and those with negative serology (3.04 +/- 0.61 g/100 ml). Thus the null hypothesis of no association between infection with T. cruzi and serum albumin is accepted. Gamma-globulin levels were elevated in both groups and were significantly greater (p less than 0.05) in the group with positive T. cruzi serology (1.91 +/- 0.41 g/100 ml) than in the group with negative serology (1.75 +/- 0.41 g/100 ml). The serum albumin levels suggest that malnutrition (either associated with low protein intake or increased loss due to hookworm) is a major problem and unlikely to change if T. cruzi transmission was controlled.
The mean +/-s.d. hair zinc levels of 45 pre-school and 70 school children, age 1-12 years, were 123 +/- 74 and 103 +/- 74 micrograms/g hair, respectively. The prevalence of zinc levels less than 70 micrograms/g 15 per cent (9 and 19 per cent for pre-school and school children, respectively). Anthropometric measurements showed that 25 per cent suffered from chronic malnutrition. The form of malnutrition manifested was exclusively stunting, ie, low height-for-age in the presence of adequate weight-for-height. No association was found between low hair zinc levels and nutritional status.
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A simplified method was used to analyze the diets of 31 poor families in the city of Ilhéus, Bahia, Brazil. The results are presented in terms of frequency of foods consumed, nutritional density and theoretical adequacy of the diet. Intrafamilial distribution of food intake was not considered in the analysis. Results show that the home diet was very limited in variety; only eight of the 46 items in the dietary frequency were consumed by 50% or more of the sample. Nutrient density was low for calcium, riboflavin, vitamin A and zinc. Energy density, as measured by the ratio of fat calories to protein calories (G/P) was 1.0, value considered nutritionally inadequate. Protein provided 16% of the energy and, of all nine nutrients analyzed, presented the highest levels of intake compared to recommended amounts. Theoretically, the groups at greater nutritional risk were women and children.
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