RESUMO
Differential scanning calorimetry (DSC) and a Rancimat method apparatus were applied to evaluate the oxidative stability of buriti pulp oil (Mauritia flexuosa Mart), rubber seed oil (Hevea brasiliensis), and passion fruit oil (Passiflora edulis). The Rancimat measurements taken for the oxidative induction times were performed under isothermal conditions at 100°C and in an air atmosphere. The DSC technique involved the oxidation of oil samples in an oxygen-flow DSC cell. The DSC cell temperature was set at five different isothermal temperatures: 100, 110, 120, 130 and 140°C. During the oxidation reaction, an increase in heat was observed as a sharp exothermic curve. The value T(0) represents the oxidative induction time, which is determined from the downward extrapolated DSC oxidative curve verses the time axis. These curves indicate a good correlation between the DSC T(0) and oxidative stability index (OSI) values. The DSC method is useful because it consumes less time and less sample.
Assuntos
Varredura Diferencial de Calorimetria/métodos , Óleos de Plantas/química , Cromatografia Gasosa , Ácidos Graxos/análise , Oxirredução , América do Sul , TermogravimetriaRESUMO
INTRODUCTION: Based on the fact that there is evidence of an association between low birth weight and neonatal and infant morbi-mortality, the World Health Organization considered birth weight as the main isolated factor associated with infant's survival. A study was undertaken to identify risk factors associated with low birth weight, using epidemiological and demographic variables present on the Birth Certificates, the source of data for the System of Information on Newborn Infants of the Brazilian Ministry of Health, for the purpose of motivating the use and the analysis of data currently generated in hospitals. METHOD: The distribution, by birth weight, of 14,784 single hospital newborn infants from five cities of the State of S. Paulo, Brazil, in an observation period of six months (1992), was analysed. Statistical analysis was based on point estimates (average, median and standard deviation) measures of association and confidence intervals (95%) of the prevalence ratios. RESULTS AND CONCLUSIONS: The highest proportion (10.4%) of low birth weight infants (weight less than 2,500 g) occurred in Itararé, the city with the highest infant mortality rate in the State, the overall proportion being 7.5%. Significant statistical associations between low birth weight and sex (female), gestational age (less than 37 weeks), mother's age (adolescent and 35 or more years of age) and parity were detected. The use of Birth Certificates in epidemiological and public health studies is highly recommended because of their validity, great importance and high coverage.
Assuntos
Estudos Epidemiológicos , Recém-Nascido de Baixo Peso , Sistemas de Informação , Adolescente , Adulto , Brasil/epidemiologia , Intervalos de Confiança , Fatores Epidemiológicos , Feminino , Humanos , Recém-Nascido , Masculino , PrevalênciaRESUMO
The dysregulation of the immune response by malaria parasite has been considered as a possible constraint to the effectiveness of malaria vaccination. In spite of the important role interleukin-1 (IL-1) plays on the immunoregulation, and its ability to mimic various features of clinical malaria, reports on IL-1 in malaria are lacking. We found that only 2 out of 35 subjects with acute malaria showed increased levels of serum IL-1 alpha by enzyme immunoassay. To assess whether IL-1 could interfere with T-lymphocyte responses, blood mononuclear cells from patients infected with Plasmodium falciparum, P. vivax, or healthy subjects were cultured with phytohemagglutinin, and lymphocyte proliferation measured 72 h later by 3H-thymidine incorporation. Our data showed that T-lymphocyte responses are depressed both in P. falciparum (10,500 +/- 2,900) and P. vivax malaria (13,000 +/- 3,300), as compared to that of healthy individuals (27,000 +/- 3,000). Addition of IL-1 partially reversed depression of malaria lymphocytes, but had no effect on normal cells. On the other hand, T-lymphocytes from malaria infected-subjects presented a minimal decrease in proliferation, when cultured in the presence of exogenous PGE2. These data indicate the occurrence of two defects of immunoregulation in malaria: a deficiency of IL-1 production by monocytes/macrophages, and an increased resistance of lymphocytes to the antiproliferative effect of PGE2.