Mediators of ethnic-associated differences in infant birth weight.
(9/3145)
PURPOSE: To examine whether ethnic differences in low birth weight babies of low-income women may be explained in part by group differences in prenatal health behaviors and psychosocial factors. METHODS: A prospective, survey of 1,071 low-income, primiparous African-American and Mexican-origin women was conducted in Los Angeles County, California. In face-to-face interviews, data were obtained on substance use, prenatal stress, social support, attitudes toward pregnancy, initiation of prenatal care, and medical risk. Medical chart data were abstracted regarding medical risk factors and labor, delivery, and neonatal data. Interview data were linked with birth outcome data retrieved from maternal medical records. Structural equation modeling was used to test a hypothesized model in which differences in birth weight were expected to be mediated by ethnic differences in substance use, psychosocial factors, and medical risk. RESULTS: As expected, African-American women delivered babies of earlier gestational age and lower birth weight than did women of Mexican origin. Direct predictors of low birth weight were use of drugs and cigarettes, prenatal stress, and positive attitudes toward pregnancy; together, these factors accounted for the observed ethnic differences in birth weight. CONCLUSION: These data contribute to our understanding of the factors that may account for ethnic-associated differences in low birth weight. (+info)
A mutation in the transmembrane/luminal domain of the ryanodine receptor is associated with abnormal Ca2+ release channel function and severe central core disease.
(10/3145)
Central core disease is a rare, nonprogressive myopathy that is characterized by hypotonia and proximal muscle weakness. In a large Mexican kindred with an unusually severe and highly penetrant form of the disorder, DNA sequencing identified an I4898T mutation in the C-terminal transmembrane/luminal region of the RyR1 protein that constitutes the skeletal muscle ryanodine receptor. All previously reported RYR1 mutations are located either in the cytoplasmic N terminus or in a central cytoplasmic region of the 5,038-aa protein. The I4898T mutation was introduced into a rabbit RYR1 cDNA and expressed in HEK-293 cells. The response of the mutant RyR1 Ca2+ channel to the agonists halothane and caffeine in a Ca2+ photometry assay was completely abolished. Coexpression of normal and mutant RYR1 cDNAs in a 1:1 ratio, however, produced RyR1 channels with normal halothane and caffeine sensitivities, but maximal levels of Ca2+ release were reduced by 67%. [3H]Ryanodine binding indicated that the heterozygous channel is activated by Ca2+ concentrations 4-fold lower than normal. Single-cell analysis of cotransfected cells showed a significantly increased resting cytoplasmic Ca2+ level and a significantly reduced luminal Ca2+ level. These data are indicative of a leaky channel, possibly caused by a reduction in the Ca2+ concentration required for channel activation. Comparison with two other coexpressed mutant/normal channels suggests that the I4898T mutation produces one of the most abnormal RyR1 channels yet investigated, and this level of abnormality is reflected in the severe and penetrant phenotype of affected central core disease individuals. (+info)
Plasma leptin concentrations in Pima Indians living in drastically different environments.
(11/3145)
OBJECTIVE: Plasma leptin, an important signal for the regulation of energy stores, is known to be influenced by many hormonal factors, but may also be affected by behavioral and environmental factors. The purpose of this study was to investigate the impact of lifestyle (diet composition, level of physical activity) on plasma leptin concentrations among Pima Indians living in drastically different environments. RESEARCH DESIGN AND METHODS: We studied 224 Mexican Pima Indians (115 women, 109 men) living a traditional lifestyle in a remote, mountainous area of northwest Mexico and 418 U.S. Pima Indians (281 women, 137 men) living a North American lifestyle on the Gila River Indian Reservation in Arizona. We hypothesized that the absolute value of leptin would be lower in Mexican Pima Indians because of their lower percent body fat, but could be further influenced by their lifestyle, independent of body composition. RESULTS: Leptin concentration (enzyme-linked immunosorbent assay [ELISA]) was strongly correlated with percent fat (bioimpedance) in Mexican Pima Indians (r = 0.83, P < 0.0001) and U.S. Pima Indians (r = 0.86, P < 0.0001). Among U.S. Pima Indians, independent of percent fat, subjects with type 2 diabetes had lower leptin than nondiabetic subjects (difference = 6.9 +/- 1.0 ng/ml, P < 0.002). Among nondiabetic subjects, Mexican Pima Indians had lower absolute leptin concentrations than U.S. Pima Indians, but higher after adjustment for percent body fat, waist circumference, age, and sex. In a subset of 70 pairs of subjects matched for sex and percent body fat, leptin concentration was 4.4 +/- 1.0 ng/ml (P < 0.0001) higher in Mexican Pima Indians versus U.S. Pima Indians. CONCLUSIONS: These results suggest that independent of body composition, leptin concentration may be increased by environmental factors, such as a high-carbohydrate diet and a high level of physical activity. (+info)
Gene differences between third-chromosome inversions of Drosophila pseudobscura.
(12/3145)
Associations of alleles of the acid phosphatase-3 locus with the different third-chromosome inversions from different populations of D. pseudoobscura are described. We observe only the allele AP-3(1.0) in the Standard and Arrowhead inversions and the allele AP-3.98 in the Santa Cruz, Treeline, Cuernavaca and the Pikes Peak arrangements. The Chiricahua gene arrangement is polymorphic. (+info)
The public/private mix and human resources for health.
(13/3145)
This paper examines the general question of the public/private mix in health care, with special emphasis on its implications for human resources. After a brief conceptual exercise to clarify these terms, we place the problem of human resources in the context of the growing complexity of health systems. We next move to an analysis of potential policy alternatives. Unfortunately, a lot of the public/private debate has looked only at the pragmatic aspects of such alternatives. Each of them, however, reflects a specific set of values--an ideology--that must be made explicit. For this reason, we outline the value assumptions of the four major principles to allocate resources for health care: purchasing power, poverty, socially perceived priority, and citizenship. Finally, the last section discusses some of the policy options that health care systems face today, with respect to the combinations of public and private financing and delivery of services. The conclusion is that we need to move away from false dichotomies and dilemmas as we search for creative ways of combining the best of the state and the market in order to replace polarized with pluralistic systems. The paper is based on a fundamental premise: The way we deal with the question of the public/private mix will largely determine the shape of health care in the next century. (+info)
Breastfeeding promotion and priority setting in health.
(14/3145)
An increase in exclusive breastfeeding prevalence can substantially reduce mortality and morbidity among infants. In this paper, estimates of the costs and impacts of three breastfeeding promotion programmes, implemented through maternity services in Brazil, Honduras and Mexico, are used to develop cost-effectiveness measures and these are compared with other health interventions. The results show that breastfeeding promotion can be one of the most cost-effective health interventions for preventing cases of diarrhoea, preventing deaths from diarrhoea, and gaining disability-adjusted life years (DALYs). The benefits are substantial over a broad range of programme types. Programmes starting with the removal of formula and medications during delivery are likely to derive a high level of impact per unit of net incremental cost. Cost-effectiveness is lower (but still attractive relative to other interventions) if hospitals already have rooming-in and no bottle-feeds; and the cost-effectiveness improves as programmes become well-established. At an annual cost of about 30 to 40 US cents per birth, programmes starting with formula feeding in nurseries and maternity wards can reduce diarrhoea cases for approximately $0.65 to $1.10 per case prevented, diarrhoea deaths for $100 to $200 per death averted, and reduce the burden of disease for approximately $2 to $4 per DALY. Maternity services that have already eliminated formula can, by investing from $2 to $3 per birth, prevent diarrhoea cases and deaths for $3.50 to $6.75 per case, and $550 to $800 per death respectively, with DALYs gained at $12 to $19 each. (+info)
Childcare needs of female street vendors in Mexico City.
(15/3145)
This article reports on strategies developed by female street vendors (vendedoras ambulantes) in Mexico City to ensure the care of their young children in the absence of a specific and operational government policy to fulfil this need. The information concerning child care and health was gathered by a survey of 426 street traders selected by multi-stage random cluster sampling in four of the administrative districts (delegaciones politicas) of Mexico City during 1990. It was found that, as mothers of young children, street vendors most frequently looked after their children personally on the street or left them with other members of the family. Related factors were availability of alternative child care providers in the family, the age of the children and working conditions of the mother. Children who remained on the streets with their mothers suffered more frequently from gastro-intestinal diseases and accidents than the national average. The incidence of acute respiratory diseases, however, was similar in the cases of maternal care in the street and care by family members in another environment. Existing public health measures show a greater concern for the health of food consumers than that of workers in this area. Current public policy seeks to regulate street vending activities and to concentrate traders in ad hoc areas and facilities. Our research results document the need for actions that can contribute to an improvement in the care and health conditions of these young children. (+info)
Infant mortality due to acute respiratory infections: the influence of primary care processes.
(16/3145)
A population-based case control study was conducted to ascertain whether the process of primary care can be a determinant of infant mortality due to Acute Respiratory Infection (ARI). Cases were 118 infants who died from ARI, individually matched with 118 infants who suffered an ARI episode and recovered. Information was gathered through interviewing mothers. Study variables were assembled into five subsets: children's characteristics; mothers' characteristics; access to medical services; process of primary care, and; sociodemographic variables. An index per subset was built to analyze the independent influence of each on ARI death risk. The index was constructed upon the weighted sum of the adjusted odds ratios (OR) within each subset. Then, the values of each index were collapsed into high/low values with the 50 percentile as a cut-off value. Next, by means of a conditional logistic regression procedure, an explanatory model of ARI mortality was obtained. The final multivariate model included the indexes that showed an independent effect: I) Process of care (OR 9.68, CI 95% 3.59-26.1): inadequate referral, attention provided by more than one physician and being attended by a private physician; II) children's characteristics (OR 7.22, CI 95% 2.35-22.2): perinatal history, lack of breast-feeding and incomplete immunization scheme; III) access to medical services (OR 5.27, CI 95% 2.02-13.7): geographic and economic barriers, lack of confidence in public health services, and; IV) mothers' characteristics (OR 4.03, CI 95% 1.18-13.8), mainly represented by untimely care seeking. We conclude that the management of the disease is a key determinant in which factors relating to the mother and the health services are strongly related. Our study reveals untimely care seeking, difficult access and inadequate disease treatment as important factors which deserve careful attention in the future. We also confirm the importance of biological determinants previously described. A main strategy to reduce infant mortality due to ARI should be to encourage training of primary care physicians, including private practitioners, focused on providing effective case management and emphasizing the education to mothers. (+info)