Effect of phenylurea herbicides on soil microbial communities estimated by analysis of 16S rRNA gene fingerprints and community-level physiological profiles.
(9/16506)
The effect of three phenyl urea herbicides (diuron, linuron, and chlorotoluron) on soil microbial communities was studied by using soil samples with a 10-year history of treatment. Denaturing gradient gel electrophoresis (DGGE) was used for the analysis of 16S rRNA genes (16S rDNA). The degree of similarity between the 16S rDNA profiles of the communities was quantified by numerically analysing the DGGE band patterns. Similarity dendrograms showed that the microbial community structures of the herbicide-treated and nontreated soils were significantly different. Moreover, the bacterial diversity seemed to decrease in soils treated with urea herbicides, and sequence determination of several DGGE fragments showed that the most affected species in the soils treated with diuron and linuron belonged to an uncultivated bacterial group. As well as the 16S rDNA fingerprints, the substrate utilization patterns of the microbial communities were compared. Principal-component analysis performed on BIOLOG data showed that the functional abilities of the soil microbial communities were altered by the application of the herbicides. In addition, enrichment cultures of the different soils in medium with the urea herbicides as the sole carbon and nitrogen source showed that there was no difference between treated and nontreated soil in the rate of transformation of diuron and chlorotoluron but that there was a strong difference in the case of linuron. In the enrichment cultures with linuron-treated soil, linuron disappeared completely after 1 week whereas no significant transformation was observed in cultures inoculated with nontreated soil even after 4 weeks. In conclusion, this study showed that both the structure and metabolic potential of soil microbial communities were clearly affected by a long-term application of urea herbicides. (+info)
Comparison of flagellin genes from clinical and environmental Pseudomonas aeruginosa isolates.
(10/16506)
Pseudomonas aeruginosa, an important opportunistic pathogen, was isolated from environmental samples and compared to clinically derived strains. While P. aeruginosa was isolated readily from an experimental mushroom-growing unit, it was found only rarely in other environmental samples. A flagellin gene PCR-restriction fragment length polymorphism analysis of the isolates revealed that environmental and clinical P. aeruginosa strains are not readily distinguishable. The variation in the central regions of the flagellin genes of seven of the isolates was investigated further. The strains used included two strains with type a genes (998 bp), four strains with type b genes (1,258 bp), and one strain, K979, with a novel flagellin gene (2,199 bp). The route by which flagellin gene variation has occurred in P. aeruginosa is discussed. (+info)
Psychological well-being 3 years after severe stroke.
(11/16506)
BACKGROUND AND PURPOSE: Stroke often has a very negative influence on the victims' perception of their life situation. The aim of this study was therefore to assess the subjects' long-term psychological well-being and to explore associations between subject characteristics, impairments, disabilities, and psychological well-being. METHODS: Of 100 subjects rehabilitated at a specialized geriatric stroke ward after the acute phase, 47 survivors were assessed in their homes 3 years after discharge and interviewed regarding their psychological well-being with the Philadelphia Geriatric Center Morale Scale (PGCMS). RESULTS: Sixty-four percent of the subjects were classified as having high scores for psychological well-being or fell within the middle range. In a cluster analysis, depression was shown to have the strongest association with the subjects' PGCMS scores. Variables including the subjects' social situation and functions as well as age, gender, ability to communicate, and need for help showed a much weaker association with the PGCMS. CONCLUSIONS: More than half of the stroke subjects were classified as having levels of psychological well-being that were good or fairly good. The strong association between PGCMS scores and depression indicates the importance of detecting and treating depression and of following up initiated therapy after stroke. (+info)
Molecular analysis of the genetic variation among penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae serotypes in Canada.
(12/16506)
Few studies have examined the genetic relatedness within and between serotypes of Streptococcus pneumoniae. Penicillin-susceptible S. pneumoniae (PSSP) isolates (n=170) and penicillin-resistant S. pneumoniae (PRSP) isolates (n=48) belonging to 13 different serotypes from across Canada were studied to further understand the molecular epidemiology of S. pneumoniae. PRSP of serotypes 6B, 14, and 19F appeared to be novel clones, differentiated by pulsed-field gel electrophoresis from the recognized international penicillin-resistant clones belonging to these serotypes. In addition, not all PRSP strains shared similar genetic backgrounds with PSSP strains of the same serotype, suggesting that in Canada, certain PRSP strains have emerged from new unique lineages of PRSP. Although there was significant heterogeneity among S. pneumoniae of different serotypes, certain serotypes (3, 7F, and 22F) appeared to be more clonally related despite having originated from different geographic regions. (+info)
Prevalence and social correlates of cardiovascular disease risk factors in Harlem.
(13/16506)
OBJECTIVES: This study examined the prevalence, social correlates, and clustering of cardiovascular disease risk factors in a predominantly Black, poor, urban community. METHODS: Associations of risk factor prevalences with sociodemographic variables were examined in a population-based sample of 695 men and women aged 18 to 65 years living in Central Harlem. RESULTS: One third of the men and women were hypertensive, 48% of the men and 41% of the women were smokers, 25% of the men and 49% of the women were overweight, and 23% of the men and 35% of the women reported no leisure-time physical activity over the past month. More than 80% of the men and women had at least 1 of these risk factors, and 9% of the men and 19% of the women had 3 or more risk factors. Income and education were inversely related to hypertension, smoking, and physical inactivity. Having 3 or more risk factors was associated with low income and low education (extreme odds ratio [OR] = 10.2, 95% confidence interval [CI] = 3.0, 34.5 for education; OR = 3.7, CI = 1.6, 8.9 for income) and with a history of unstable work or of homelessness. CONCLUSIONS: Disadvantaged, urban communities are at high risk for cardiovascular disease. These results highlight the importance of socioenvironmental factors in shaping cardiovascular risk. (+info)
Interpreting patterns of gene expression with self-organizing maps: methods and application to hematopoietic differentiation.
(14/16506)
Array technologies have made it straightforward to monitor simultaneously the expression pattern of thousands of genes. The challenge now is to interpret such massive data sets. The first step is to extract the fundamental patterns of gene expression inherent in the data. This paper describes the application of self-organizing maps, a type of mathematical cluster analysis that is particularly well suited for recognizing and classifying features in complex, multidimensional data. The method has been implemented in a publicly available computer package, GENECLUSTER, that performs the analytical calculations and provides easy data visualization. To illustrate the value of such analysis, the approach is applied to hematopoietic differentiation in four well studied models (HL-60, U937, Jurkat, and NB4 cells). Expression patterns of some 6,000 human genes were assayed, and an online database was created. GENECLUSTER was used to organize the genes into biologically relevant clusters that suggest novel hypotheses about hematopoietic differentiation-for example, highlighting certain genes and pathways involved in "differentiation therapy" used in the treatment of acute promyelocytic leukemia. (+info)
Changing trends in barriers to cataract surgery in India.
(15/16506)
Cataract is a major cause of blindness in Asia. Efforts in India to provide cataract surgical services have had limited success in reaching the cataract-blind population. Earlier studies identified the major barriers to cataract surgery as poverty, lack of transportation or felt need, or sex related; and the critical barriers in rural areas as lack of awareness, difficult access, and cost. Compared with these earlier data, the results of the present study in Karnataka State indicate a shift in the character of the barriers. They now appear to be more related to case selection and service provision. These shifts are analysed and alternative strategies to increase the uptake to cataract surgery are recommended. (+info)
Caffeine withdrawal: a parametric analysis of caffeine dosing conditions.
(16/16506)
Although caffeine is the most widely used behaviorally active drug in the world, caffeine physical dependence has been only moderately well characterized in humans. Four double-blind experiments were conducted in independent groups of healthy participants to assess the conditions under which withdrawal symptoms occur upon cessation of low to moderate doses of caffeine. In experiment 1, there was no evidence that the range or magnitude of caffeine withdrawal symptoms differed when 300 mg of caffeine was consumed as a single dose in the morning versus 100 mg at three time points across the day. In experiment 2, both the range and severity of withdrawal increased as a function of caffeine maintenance dose (100, 300, and 600 mg/day), with even the lowest dose (100 mg) producing significant caffeine withdrawal. Experiment 3 showed that when individuals were maintained on 300 mg caffeine/day and tested with a range of lower doses (200, 100, 50, 25, and 0 mg/day), a substantial reduction in caffeine consumption (+info)