Sex-biased hatching order and adaptive population divergence in a passerine bird.
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Most species of birds can lay only one egg per day until a clutch is complete, and the order in which eggs are laid often has strong and sex-specific effects on offspring growth and survival. In two recently established populations of the house finch (Carpodacus mexicanus) in Montana and Alabama, breeding females simultaneously adjusted the sex and growth of offspring in relation to their position in the laying order, thereby reducing the mortality of sons and daughters by 10 to 20% in both environments. We show experimentally that the reduction in mortality is produced by persistent and sex-specific maternal effects on the growth and morphology of offspring. These strong parental effects may have facilitated the rapid adaptive divergence among populations of house finches. (+info)
Angiotensin II receptor blockade does not improve left ventricular function and remodeling in subacute mitral regurgitation in the dog.
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OBJECTIVES: We hypothesized that angiotensin II type-1 (AT(1)) receptor blocker (AT(1)RB) would prevent adverse left ventricular (LV) remodeling and LV dysfunction when started at the outset of mitral regurgitation (MR). BACKGROUND: Little is known regarding the efficacy of AT(1)RB treatment of MR. METHODS: Mitral regurgitation was induced by chordal disruption in adult mongrel dogs. Six normal dogs (NLs) were compared to six untreated MR dogs (MR) and seven dogs treated with the receptor blocker irbesartan (MR+AT(1)RB) started 24 h after induction of MR (60 mg/kg p.o. b.i.d.) and continued for three months. RESULTS: Treatment with AT(1)RB decreased systemic vascular resistance but did not significantly improve cardiac output, LV end-diastolic dimension (LVEDD) or LVEDD/wall thickness compared to untreated MR dogs. Resting isolated cardiomyocyte length increased in MR versus NLs and was further increased in AT(1)RB dogs. Left ventricular end-systolic dimension increased to a greater extent from baseline in AT(1)RB dogs versus untreated MR dogs (29 +/- 9% vs. 12 +/- 6%, p < 0.05), despite a significantly lower LV peak systolic pressure in AT(1)RB dogs. Plasma-angiotensin (ANG) II was elevated greater than threefold in both MR and MR+AT(1)RB versus NLs. In contrast, intracardiac ANG II was increased greater than twofold in MR dogs versus NLs, but was normalized by AT(1)RB. CONCLUSIONS: The use of AT(1)RB decreased systemic vascular resistance and attenuated local expression of the renin-angiotensin system but did not prevent adverse LV chamber and cardiomyocyte remodeling. These results suggest that blockade of the AT(1) receptor does not improve LV remodeling and function in the early myocardial adaptive phase of MR. (+info)
Occupational electrocutions in Jefferson County, Alabama.
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Few studies have presented the general epidemiology of electrocution deaths using local medical examiner data. Data were obtained from coroner/medical examiner's files for electrocution deaths occurring between 1981 and 1998. All 27 occupational electrocutions were among men; 92.6% were white and 7.4% were black, with a mean age of 33.1 years. The rates of high- and low-voltage electrocution were similar. Low-voltage deaths showed a seasonal pattern, with the largest numbers in July, August and October. Deaths occurred most frequently among electricians and electrical helpers. The level of detail available from medical examiner records permits more complete evaluation of injury patterns than is possible using death certificate data; however, even more detailed studies, exploring worker activity at the time of injury, education, experience and training, are needed. (+info)
Demographics and correlates of five-year change in echocardiographic left ventricular mass in young black and white adult men and women: the Coronary Artery Risk Development in Young Adults (CARDIA) study.
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OBJECTIVE: The goal of this study was to determine the presence and correlates of change (Delta) in left ventricular (LV) mass by echocardiography in young adults. BACKGROUND: Left ventricular mass is known to be a powerful independent predictor for cardiovascular disease events in adults. However, little is known about Delta in LV mass over time in young adults. METHODS: Coronary Artery Risk Development in Young Adults (CARDIA) is a multicenter, longitudinal, population-based study of black and white men and women who were ages 23 to 35 at the time of their initial two-dimensionally directed M-mode echocardiography exam (year 5); half the cohort had a repeat echocardiography exam five years later (year 10). Data were analyzed from 1,189 participants who had paired echocardiography studies. To minimize reader variability, blinded measurements on initial and repeat echocardiography were performed nearly contemporaneously by the same reader. RESULTS: In multilinear regression analyses, significant (p < 0.05) predictors of year 10 two-dimensional guided M-mode LV mass included initial LV mass, initial body mass index (BMI) and change in BMI for all race/gender subgroups. Initial systolic blood pressure (SBP) was a significant predictor of year 10 LV mass in white men and black women; change in SBP was significant in black women with a trend towards significance in white women. Left ventricular mass remained constant in all race/gender subgroups, except black women, where it increased (by 5.9 g [mean]). Black women also had the largest increases in BMI and SBP. In black women, a five-year weight gain of 20 pounds and a 15-mm Hg increase in SBP would be expected to be associated with a 9% to 12% increase in LV mass. CONCLUSIONS: Particularly in black women, weight and blood pressure control may be important community health and treatment goals to prevent LV hypertrophy. (+info)
Identification of mosquito avian-derived blood meals by polymerase chain reaction-heteroduplex analysis.
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A polymerase chain reaction (PCR) heteroduplex assay (HDA) was developed to identify avian derived mosquito blood meals to the species level. The assay used primers amplifying a fragment of the cytochrome B gene from vertebrate but not invertebrate species. In Culex tarsalis fed on quail, PCR products derived from the quail cytochrome B gene were detected seven days post-engorgement. In an analysis of wild-caught mosquitoes, 85% of blood-fed mosquitoes produced detectable PCR products. Heteroduplex patterns obtained from bird-derived PCR products were found to permit the unambiguous identification of all species examined. No intraspecific variation in HDA patterns was found. The PCR-HDA was used to characterize blood meals in wild caught Cx. tarsalis. Of the 67 blood meals analyzed, 60% were derived from avian sources. Of the avian blood meals, 65% were derived from a single host, the common grackle. (+info)
Systemic lupus erythematosus in three ethnic groups. XI. Sources of discrepancy in perception of disease activity: a comparison of physician and patient visual analog scale scores.
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OBJECTIVE: To compare patient's and physician's assessment of disease activity in a multiethnic (Hispanic, African American, and Caucasian) cohort of systemic lupus erythematosus (SLE) patients. METHODS: Three hundred patients with SLE from the LUMINA (Lupus in Minority populations: Nature versus nurture) cohort were included. Disease activity was assessed with the Systemic Lupus Activity Measure (SLAM); patients and physicians assessed disease activity using a 10-cm anchored visual analog scale (VAS). The difference between VAS scores was termed discrepancy (>1 cm was considered a priori clinically relevant). Selected sociodemographic, clinical, behavioral, and psychological variables were examined in relation to discrepancy in univariable and multivariable models adjusting for the physician global VAS score in order to eliminate ceiling and floor effects. RESULTS: A discrepancy was exhibited by 58% of the patients. Abnormal laboratory findings were negatively associated with discrepancy, and poor self-perceived functioning and joint involvement were positively associated with discrepancy. Ethnicity did not account for discrepant perception of disease activity. CONCLUSION: Patients and physicians rate disease activity in SLE differently. Physicians appear to place more emphasis on laboratory features while patients place more emphasis on function. (+info)
Predictors of infection with Trichomonas vaginalis: a prospective study of low income African-American adolescent females.
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OBJECTIVES: To identify psychosocial predictors of Trichomonas vaginalis infection among low income African-American adolescent females living in a high risk urban area of the United States. METHODS: Baseline plus 6 and 12 month follow up data collected as part of an HIV prevention intervention trial were utilised. The baseline sample consisted of 522 African-American females, 14-18 years of age. Recruitment sites were located in low income neighbourhoods of Birmingham, Alabama, characterised by high rates of unemployment, substance abuse, violence, teenage pregnancy, and sexually transmitted infections. Self administered vaginal swab specimens were cultured for T vaginalis. Baseline measures collected as part of a self administered survey and face to face interviews were used to predict subsequent infection with T vaginalis at any of the three assessment periods conducted over the span of 1 year. RESULTS: At baseline, 12.9% were diagnosed with T vaginalis. At the 6 and 12 month follow ups, T vaginalis was diagnosed in 8.9% and 10.2%, respectively. The strongest multivariate predictor of T vaginalis infection was biologically confirmed marijuana use; those using marijuana were more than six times as likely to test positive for T vaginalis (adjusted odds ratio (AOR) = 6.2, p = 0.0003). Other multivariate predictors were reporting that typical sex partners were at least 5 years older (AOR = 2.6; p = 0.005), reporting sex with non-steady partners (AOR = 1.9; p = 0.02), and history of delinquency (AOR = 1.3; p = 0.02). The odds of testing positive increased by 31% for every one unit increase on a six item scale measure of delinquency. CONCLUSIONS: Infection with T vaginalis was common and significant multivariate predictors comprised a constellation of problem behaviours, each of which are potentially amenable to behavioural intervention. (+info)
Molecular typing of Mycobacterium tuberculosis strains with a common two-band IS6110 pattern.
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We conducted a program of population-based molecular typing of all Mycobacterium tuberculosis isolates obtained in Alabama since 1994. Of 2452 isolates, 1013 (41%) had fewer than 6 bands of IS6110; 348 (14%) had a single two-band pattern (JH2). With conventional epidemiologic methods, we identified three groups of related patients with JH2 isolates. Spoligotyping and pattern of variable number of tandem repeats identified 10 molecular groups; two found by conventional methods were subdivided. (+info)