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Differences in blood pressure among individuals of African ancestry living in the United States compared with those living in Africa suggest that the high prevalence of hypertension among African Americans may be due in part to environmental factors. There are a number of environmental models that attempt to account for the high rate of hypertension among African Americans. One model proposes that a strong African self-concept protects African-American adolescents from the hypertensive effects of social stress. This model was tested during a blood pressure survey of 333 adolescents in three urban Los Angeles high schools. African self-concept was assessed using a three-item scale. The average score for the three items was strongly related to systolic blood pressure among African-American male adolescents. After controlling for age, body mass index, and parent''s education in regression analyses, the relation was reduced, but an effect remained. The model suggests that the hypertensive effects of the environment will operate unless the pathway from environmental stress to hypertension is blocked by a strong African-American self-concept.  相似文献   
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The African pygmy mice, subgenus Nannomys, constitute the most speciose lineage of the genus Mus with 19 recognized species. Although morphologically very similar, they exhibit considerable chromosomal diversity which is here confirmed and extended by the G-banding analysis of 65 mice from West and South Africa. On the basis of their karyotype and distribution area, the specimens were assigned to at least five species. Extensive differentiation both within and between species was observed that involved almost exclusively Robertsonian translocations, 23 of which are newly described. Two of the rearrangements were sex chromosome-autosome translocations, associated in some cases with partial deletions of the X or Y chromosomes. Several authors have predicted that the highly deleterious effect of this rearrangement would be reduced if the sex and autosomal segments were insulated by a block of centromeric heterochromatin. The C-banding analyses performed showed that among the species carrying X-autosome translocations, one followed the expected pattern, while the other did not. In this case, functional isolation of the sex and autosome compartments must involve other repetitive sequences or genomic traits that require further molecular characterization. Such studies will provide insight into the causes and consequences of the high diversity of sex chromosome rearrangements in this subgenus.  相似文献   
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This article reviews major risk factors for cigarette smoking, alcohol, and other drug abuse and promising community-based approaches to primary prevention. In a longitudinal experimental study, 8 representative Kansas City communities were assigned randomly to program (school, parent, mass media, and community organization) and control (mass media and community organization only) conditions. Programs were delivered at either 6th or 7th grade, and panels were followed through Grade 9 or 10. The primary findings were (a) significant reductions at 3 years in tobacco and marijuana use and (b) equivalent reductions for youth at different levels of risk. This study provides evidence that a comprehensive community program-based approach can prevent the onset of substance abuse and that the benefits are experienced equally by youth at high and low risk.  相似文献   
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Backache and its prevention   总被引:1,自引:0,他引:1  
Low back pain (LBP) is a symptom produced by disorders of the lumbar spine. It may be impossible to prevent all LBP, and while most episodes of acute LBP are self-limiting, the disorders producing recurrent and chronic LBP are usually incurable. The difficulties in diagnosing the disorders complicate effective management and prevention; however, prevention of spinal trauma reduces the incidence and prevalence of LBP. Effective preventive measures include the reduction of road trauma and smoking, improved vehicle seating, the control of vehicle vibrations, careful worker selection, job redesign, improved physical fitness, and the proper use of the spine in the home, at school, at work, and in sports. Frymoyer includes these and other measures in his tips to prevent LBP. Medical and paramedical professionals must be sure their investigations and treatments do not contribute to making the disorder chronic and more complex. The inappropriate use and interpretation of spinal investigations and the overzealous use of surgical procedures certainly add to the problem. An agreement on an acceptable "glossary" of lumbar terms and clinical syndromes is needed together with a new research emphasis on prevention and a continuation of research efforts in epidemiology, etiology, and management of LBP. Effective public education is vital, so that everyone is aware of the causes and methods of prevention of LBP. Discussion on the "20th-century epidemic of LBP" may be concluded on an optimistic note by citing White, who considers most LBP to be preventable and controllable with simple measures, reinforcable through public education, which can do for LBP what has been done in the field of dental hygiene.  相似文献   
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A screening programme for congenital dislocation of the hip in which physiotherapists examine all neonates is described, together with the results over a 7-year period. All easily reducible dislocated and dislocatable hips are splinted within 2-5 days of birth. Subluxable or "slidey" hips are identified and followed up but not splinted. Risk groups are also identified and followed up. There was a progressive decrease in the number of late diagnosed cases, a result suggesting that even late-presenting acetabular dysplasia can be eliminated by neonatal screening.  相似文献   
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Retinopathy is an important sequela of diabetes mellitus, but clinical risk factors for this condition have rarely been assessed in a geographically defined population. In this population-based study, the 1135 Rochester, Minnesota, residents with diabetes mellitus initially diagnosed between 1945 and 1969 (incidence cohort) were followed through their complete medical records in the community to January 1, 1982. Because most of the cases of diabetic retinopathy in Rochester residents developed in patients with non-insulin-dependent diabetes mellitus (NIDDM), risk factors for diabetic retinopathy were examined in this group (N = 1031). A proportional hazards model identified the following risk factors for diabetic retinopathy in NIDDM: elevated initial fasting blood glucose level, marked obesity, and earlier age at onset of diabetes. Stratified analyses indicated that duration of diabetes was also significantly associated with an increased risk of retinopathy. Two secular trends, increasing detection of "mild" NIDDM and decreasing risk of diabetic retinopathy, had a major effect on retinopathy risk assessment. These data also suggest that insulin therapy is not an independent risk factor for diabetic retinopathy.  相似文献   
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