Effect of physical parameters on the in situ survival of Escherichia coli MC-6 in an estuarine environment.
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Survival of Escherichia coli MC-6 of fecal origin in an estuarine environment as affected by time, water temperature, dissolved oxygen, salinity, and montmorillonite in diffusion chambers has been elucidated. Several in situ physical parameters were recorded simultaneously, and viable cell numbers were estimated. The survival of the bacteria varied seasonally. Montmorillonite addition extended the time needed for a 50% reduction of the viable cell population (t1/2) of cells by 40% over the t1/2 of cells in Rhode River water alone. The effect of this clay was not significantly greater between 50- to 1,000 mug/ml montmorillonite concentrations. In all experiments, the relationships among pairs of variables were studied by regression and correlation analysis. The slope between viable cell numbers and water temperatures increased about 50% for each 10 C increment in temperature and gave a correlation coefficient r = 0.617, significant at 95% confidence level. A similar correlation coefficient, r = 0.670, was obtained between water temperature and t1/2 of the initial cell population. In all experiments regressions were performed considering all variables after bacteria had been in the Rhode River environment for 3 days. Coefficient of multiple determination was estimated as R2 = 0.756. Approximately 75.6% of the variance of viable cell numbers can be explained by variation in water temperature, dissolved oxygen, and salinity. Simple correlation coefficients within the regression steps were also computed. Survival of bacteria was closely and negatively correlated with increasing water temperature (r = -0.717). It is suggested that water temperature is the most important factor in predicting fecal coliform survival from point and nonpoint sources in assessing water quality in an estuarine ecosystem. (+info)
Self-reported concern about food security--eight states, 1996-1998.
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Food security is defined as having access at all times to enough food for an active, healthy lifestyle (1,2). This definition implies that safe and nutritious foods are available and that household resources are sufficient to meet cost. Recognition that hunger and food security are problems in the United States led to the development and implementation of measures of hunger and food security on national surveys. One of the national health objectives for 2010 is to increase food security and reduce the risk for hunger among all households (objective 19-18) (1). To characterize state-level prevalence of concern about food security, data were analyzed for the eight states that used the Social Context Module of the Behavioral Risk Factor Surveillance System (BRFSS) during 1996-1998. This report summarizes the results of this analysis and indicates that approximately 4%-6% of adults reported a concern about having enough food for themselves or their family during the preceding month. (+info)
Impact of race on the outcome of carotid endarterectomy: a population-based analysis of 9,842 recent elective procedures.
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OBJECTIVE: To examine the influence of race and other potentially confounding variables on the outcome of carotid endarterectomy (CEA). SUMMARY: Previous studies have demonstrated that CEA is performed less frequently in black patients, although little attention has been focused on the influence of race on the outcome of surgery. METHODS: The Maryland Health Services Cost Review Commission database was reviewed to identify all elective CEA procedures performed in all nonfederal acute care hospitals in the state from 1990 through 1995 to examine the influence of race and other factors on the rates of in-hospital complications, in-hospital stroke, length of stay, and total hospital charges. RESULTS: Carotid endarterectomy was performed in 9,219 (94%) white and 623 (6%) black patients during this period. The in-hospital stroke rate was 1.7%-3. 1% among black patients and 1.6% among white patients. Black patients had a longer length of stay and higher mean hospital charges than white patients. Multivariate logistic regression analysis identified black race as an independent risk factor for in-hospital stroke. Performance of CEA by a high-volume surgeon was protective for the combined occurrence of in-hospital stroke or death, and whites were more than twice as likely to undergo surgery performed by high-volume surgeons. Conversely, undergoing surgery in a low-volume hospital was associated with in-hospital stroke, and blacks were four times as likely to use low-volume hospitals. CONCLUSIONS: Black patients who underwent elective CEA in Maryland from 1990 to 1995 had an increased incidence of in-hospital stroke, a longer hospital stay, and higher hospital charges than whites. Black race was identified as an independent risk factor for in-hospital stroke, although the reasons for this influence of race on outcome are undefined. The authors' observations also suggest the possibility of limited access to optimal surgical care among blacks, and this issue warrants further study. (+info)
Household exposure to passive cigarette smoking and serum micronutrient concentrations.
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BACKGROUND: The associations observed between passive smoking and adverse health outcomes have generated controversy. In part, this could be because the diets of passive smokers, like those of active smokers, differ from those of persons who are not exposed to cigarette smoke, especially with regard to antioxidants. OBJECTIVE: Our objective was to assess the relation between household exposure to passive smoking and serum concentrations of retinol, tocopherols, and carotenoids. DESIGN: A cross-sectional study was conducted in Washington County, MD, to compare exposure to passive smoking at home, recorded in a private census of county residents in 1975, with micronutrient concentrations assayed in serum collected in 1974. This comparison was possible for 1590 control subjects in nested case-control studies conducted between 1986 and 1998. RESULTS: Among persons who were not current smokers, those who lived with smokers tended to have lower serum total carotenoid, alpha-carotene, ss-carotene, and cryptoxanthin concentrations than did those who lived in households with no smokers. There was little evidence that exposure to passive smoking was associated with reduced serum concentrations of lutein and zeaxanthin, lycopene, retinol, alpha-tocopherol, or gamma-tocopherol. CONCLUSIONS: Among nonsmokers, exposure to passive smoking tended to be associated with lower serum concentrations of the carotenoids most strongly associated with active smoking (total carotenoids, alpha-carotene, ss-carotene, and cryptoxanthin). The associations were weaker for passive smoking than for active smoking. The consistency of the associations observed for active and passive smoking indicates that exposure to passive smoking may result in decreased circulating concentrations of selected micronutrients. (+info)
Clonal groups of penicillin-nonsusceptible Streptococcus pneumoniae in Baltimore, Maryland: a population-based, molecular epidemiologic study.
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Few data are available on the molecular subtypes of all penicillin-nonsusceptible Streptococcus pneumoniae (PNSP) from a defined population base. Pulsed-field gel electrophoresis (PFGE), serotyping, and antibiotic susceptibility testing were performed for all available invasive PNSP isolates for which the penicillin (MIC) was > or =0.1 microg/ml from Baltimore, Md., during 1995-1996 (n = 143). The dendrogram analysis of PFGE patterns included 32 distinct clonal groups. Six major clonal groups included two-thirds of the PNSP strains. Major clonal groups 2, 3, 4, and 6 strains were genetically related to four previously described international clones and were all multidrug resistant. Major clonal group 3 was genetically related to the Tennessee(23F)-4 clone and contained all four strains for which the penicillin MIC was 8 microg/ml. Most of the clonal group 1 and 5 strains had intermediate susceptibility to penicillin and were rarely multidrug resistant. The latter clonal groups represent two previously undescribed penicillin-intermediate pneumococcal clones. Clonal group homogeneity was greater for serotype 9V, 19A, and 23F strains than for serotype 6A, 6B, 14, and 19F strains. The classification of PNSP strains into clonal groups is essential for future population-based epidemiologic studies of PNSP. (+info)
Suicide acts in 8 states: incidence and case fatality rates by demographics and method.
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OBJECTIVES: This study examined incidence rates of medically identified suicide acts (self-inflicted injuries, either fatal or nonfatal) and case fatality rates by age, sex, race, and method used. METHODS: The authors analyzed data on 10,892 suicides and 57,439 attempted suicides among hospital-admitted individuals in 8 states, along with 6219 attempted suicides among individuals released from emergency departments in 2 states. RESULTS: The 8 states experienced a mean of 11 suicides and 119 attempted suicides per 100,000 residents each year. Groups with high suicide rates were men, the elderly, and Whites; groups with high attempted suicide rates were teenagers, young adults, women, and Blacks and Whites aged 25 to 44 years. Blacks aged 15 to 44 years evidenced high attempted suicide rates undocumented in previous studies. Poisoning and firearm were the most common methods used among those attempting suicide and those completing suicide acts, respectively. The most lethal method was firearm. CONCLUSIONS: The characteristics of suicides and attempted suicides differ dramatically. Method used is important in the lethality of the act. (+info)
Lessons learned from the tobacco industry's efforts to prevent the passage of a workplace smoking regulation.
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OBJECTIVES: This study assessed the implementation of tobacco industry strategies to prevent a workplace smoking regulation. METHODS: Tobacco industry internal documents were identified; hearing transcripts for the affiliations, arguments, and positions regarding the regulation of testifiers were coded; and media coverage was analyzed. RESULTS: Tobacco industry strategies sought to increase business participation and economic discussions at public hearings and to promote unfavorable media coverage of the regulation. The percentage of business representatives opposing the regulation grew from 18% (5 to 28) to 57% (13 of 23) between the hearings. Economic arguments opposing the regulation rose from 25% (7 of 28) to 70% (16 of 23). Press coverage was neutral and did not increase during the period of the regulatory hearings. CONCLUSIONS: The tobacco industry was successful in implementing 2 of its 3 strategies but was not able to prevent passage of the comprehensive workplace regulation. (+info)
The association of multiple visual impairments with self-reported visual disability: SEE project.
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PURPOSE: This report examines the relationship between psychophysical measures of visual impairment and self-reported difficulty with everyday visual tasks in a population-based sample of individuals 65 years of age and older. METHODS: Community-dwelling residents (n = 2520) of Salisbury, MD, between the ages of 65 and 84 were recruited for the study. Visual acuity under normal and low luminance, contrast and glare sensitivity, stereoacuity, and visual fields were measured. Subjective physical disability was assessed with the Activities of Daily Vision Scale (ADVS). RESULTS: In multiple regression analyses adjusted for demographic factors, cognitive status, depression, and number of comorbid medical conditions, each of the vision tests except low luminance acuity was independently associated with lower ADVS scores. The analyses indicate that a factor of 2 reduction in visual acuity or contrast sensitivity, comparable with that observed in mild to moderate lens opacity, was associated with a three- to fivefold odds of reporting difficulty with daily tasks. Although age alone was a significant risk factor for disability, it was not associated with overall ADVS score, once visual impairment and other chronic medical conditions were taken into account. CONCLUSIONS: Visual acuity, contrast and glare sensitivity, stereoacuity, and visual fields are significant independent risk factors for self-reported visual disability in an older population. Visual impairment defined by acuity alone is not the only dimension of the association with subjective disability. Additional vision measures are required to understand the impact of vision loss on everyday life. (+info)