RESUMO
A screen for Leishmania mexicana genes encoding promastigote-specific flagellar proteins resulted in isolation of genes encoding the major components of the paraflagellar rod. One of these, PFR-2, was characterized extensively. PFR-2 genes are present in the genome as a tandem array of three genes designated PFR-2A, PFR-2B, PFR-2C. PFR-2A and PFR-2B are encoded by a 3.1 transcript while PFR-2C is encoded by a 3.8-kb transcript that has a 3' UTR different from that of the 3.1-kb transcript. Both of these mRNAs were 15-fold more abundant in promastigotes than in amastigotes. Two transcripts immediately upstream of the locus were constitutively expressed while two downstream transcripts were fourfold more abundant in promastigotes than in amastigotes. The PFR genes will provide a good model system for analysis of stage-specific gene regulation in Leishmania as well as assist in the characterization of the function and organization of the paraflagellar rod.
Assuntos
Leishmania mexicana/crescimento & desenvolvimento , Leishmania mexicana/genética , Proteínas de Protozoários/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Primers do DNA/genética , DNA Complementar/genética , DNA de Protozoário/genética , Flagelos/genética , Regulação da Expressão Gênica no Desenvolvimento , Genes de Protozoários , Dados de Sequência Molecular , Mapeamento por Restrição , Homologia de Sequência do Ácido NucleicoRESUMO
OBJECTIVE: To evaluate the effect of calcium supplementation on blood pressure in children. DESIGN: Randomized, double-masked, placebo-controlled trial. SETTING AND PARTICIPANTS: One hundred one fifth-grade students in one inner-city school. INTERVENTION: Each child consumed 480 ml of juice beverages, containing either no calcium or 600 mg calcium (as calcium citrate malate) daily for 12 weeks. MEASUREMENTS: At baseline we obtained nutrient data from three sets of 2-day food records on each subject. We measured blood pressure four times on each of three weekly sittings at baseline and at follow-up. Using multiple linear regression analysis, we compared mean blood pressure change in the intervention group with that in the placebo group. RESULTS: There were 50 girls and 51 boys; 61 subjects were black. At baseline, mean age was 11.0 years, systolic and diastolic blood pressures were 101.7 and 57.7 mm Hg, daily total energy intake was 1966 kcal, and calcium intake was 827 mg. With control for age, height, hours of television watched, and baseline blood pressure, systolic blood pressure increased 1.0 mm Hg in the intervention group and 2.8 mm Hg in the placebo group (effect estimate = -1.8 mm Hg; 95% confidence interval -4.0, 0.3). In black subjects the intervention effect estimate was -2.0 mm Hg (95% confidence interval -4.4, 0.4). From lowest to highest quartile of baseline calcium intake (per 1000 kcal), the intervention effect estimates were -3.5, -2.8, -1.3, and 0.0 mm Hg (p for trend = 0.009). There was little effect on diastolic blood pressure. CONCLUSION: These data suggest a blood pressure-lowering effect of calcium supplementation in children, especially in subjects with low baseline calcium intake.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Cálcio/farmacologia , Citratos/farmacologia , Ácido Cítrico , Malatos/farmacologia , Bebidas , População Negra , Constituição Corporal , Cálcio/administração & dosagem , Cálcio da Dieta/administração & dosagem , Criança , Citratos/administração & dosagem , Registros de Dieta , Método Duplo-Cego , Ingestão de Energia , Exercício Físico , Feminino , Frutas , Humanos , Modelos Lineares , Malatos/administração & dosagem , Masculino , Televisão , Fatores de TempoRESUMO
BACKGROUND AND OBJECTIVE: The National Cholesterol Education Program guidelines recommending that children be screened to detect abnormal levels of blood lipids depend on accurate assignment to risk categories. Our objective was to assess the impact of within-person variability of blood lipids on such risk classification. DESIGN AND SUBJECTS: We measured total cholesterol (TC) and high-density lipoprotein-cholesterol (HDL-C) at three successive weekly visits in 24 children aged 6 to 9 years. MAIN OUTCOME MEASURES: Using within-person variance estimates, we constructed 95% confidence intervals to evaluate how well one, two, and three lipid measurements per child allowed assignment of risk as recommended by the National Cholesterol Education Program. RESULTS: The mean, overall, and within-person standard deviations were 145.7, 24.5, and 9.2 mg/dl, respectively, for TC, and 42.8, 10.1, and 4.6 mg/dl, respectively, for HDL-C. One TC measurement allowed confident assignment to the "acceptable" (less than 170 mg/dl) category only if less than 154.9 mg/dl, and to the "high" (greater than or equal to 200 mg/dl) category only if greater than 215.1 mg/dl. The average of two TC values allowed assignment to these categories if less than 159.3 or greater than 210.7 mg/dl, respectively. For the average of three TC values, these ranges were less than 161.3 and greater than 208.7 mg/dl, respectively. With one TC measurement, no value allowed assignment to the "borderline" (170 to 199 mg/dl) category. The average of two TC values allowed assignment to the "borderline" category if between 180.7 and 189.3 mg/dl. Using the average of three values enlarged this range by 4 mg/dl. For HDL-C, multiple measurements improved risk assignment in a similar fashion. CONCLUSION: The magnitude of within-person variability of TC and HDL-C limits the ability to classify children into risk categories recommended by the National Cholesterol Education Program.
Assuntos
Colesterol/sangue , Hipercolesterolemia/sangue , Criança , HDL-Colesterol/sangue , Estudos de Coortes , Feminino , Humanos , Hipercolesterolemia/diagnóstico , Masculino , Valor Preditivo dos Testes , Fatores de RiscoRESUMO
To determine the relationship between activity levels of parents and those of their young children, we monitored physical activity with a mechanical device, the Caltrac accelerometer, in one hundred 4- to 7-year-old children and in 99 of their mothers and 92 of their fathers. During 1 year in the Framingham Children's Study, data were obtained for an average of more than 10 hours per day for 8.6 +/- 1.8 days for the children, for 8.3 +/- 2.1 days for their mothers, and for 7.7 +/- 2.3 days for their fathers. Children of active mothers (average Caltrac accelerometer counts per hour greater than the median) were 2.0 times as likely to be active as children of inactive mothers (95% confidence interval = 0.9, 4.5); the relative odds ratio of being active for the children of active fathers was 3.5 (95% confidence interval = 1.5, 8.3). When both parents were active, the children were 5.8 times as likely to be active (95% confidence interval = 1.9, 17.4) as children of two inactive parents. Possible mechanisms for the relationship between parents' and child's activity levels include the parents' serving as role models, sharing of activities by family members, enhancement and support by active parents of their child's participation in physical activity, and genetically transmitted factors that predispose the child to increased levels of physical activity.
Assuntos
Comportamento Infantil , Exercício Físico , Pais , Criança , Pré-Escolar , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Estudos Longitudinais , MasculinoRESUMO
The prevalences of intestinal parasites among the residents of three South American Indian villages in the process of acculturation were compared with those found in earlier unpublished surveys in two newly contracted village.s Although one individual in an acculturating village harbored 11 different intestinal parasites, in general the average number of different parasitic species carried per person was somewhat higher in the newly contacted villages. Helminth egg counts, performed on direct smears of each specimen from one newly contacted village, were low. There were no sex-associated differences in prevalences. The overall prevalences, unadjusted for age, were among the highest recorded for Amerindians. No Taenia species were present. Balantidium coli was present in two acculturating villages, concomitant with the beginning of agricultural practices which include raising swine. No cases of moderate or severe protein-calorie malnutrition was observed in any of the villages during the surveys. These limited data provide a baseline for future comparisons and, perhaps, a glimpse into the past.