Toxicity of three mosquito insecticides to crayfish.
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Biomedical subjects
Publications and source records attributed to E A Paul.
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Synthetic pyrethroids often have synergists added to improve effectiveness, yet decisions regarding the use of these pesticides are often based upon toxicity tests using technical material without the synergist, piperonyl butoxide. We conducted toxicity tests with brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) to compare the toxicity of synergized and technical formulations of permethrin, sumithrin, and resmethrin. We found a significant increase in toxicity in the synergized permethrin formulation using traditional 24, 48, and 96-h tests, relative to tests with the technical formulation. However, there was little difference in toxicity between synergized and technical sumithrin until 48 h had elapsed. Many test fish were strongly intoxicated by either formulation of permethrin or sumithrin, but the synergized formulations of both chemicals affected fish at lower concentrations. Intoxication was potentially severe enough to reduce the survival of these fish in the wild. Following short (6-h) exposures, we also found a larger difference in the number of fish that died or became intoxicated between the synergized and technical formulations of permethrin and sumithrin. Finally, we tested the ability of exposed fish to swim against a current. Fish exposed for 6 h to synergized permethrin and resmethrin had far less swimming stamina than those exposed to technical formulations. We found no difference in the effect on swimming between the synergized and technical formulation of sumithrin. In general, the synergized formulations of these chemicals appeared to cause a faster response than the technical formulations. This response increases the lethal and sublethal impacts of the insecticides. We also found that sumithrin was the least toxic of the three pyrethroids. Since the maximum application rate of sumithrin is half that of the other two pyrethroids, the potential risk to wild trout in streams may be reduced.
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Breast self-examination (BSE) is widely recommended for breast cancer prevention. Following recent controversy over the efficacy of mammography, it may be seen as an alternative. We present a meta-analysis of the effect of regular BSE on breast cancer mortality. From a search of the medical literature, 20 observational studies and three clinical trials were identified that reported on breast cancer death rates or rates of advanced breast cancer (a marker of death) according to BSE practice. A lower risk of mortality or advanced breast cancer was only found in studies of women with breast cancer who reported practising BSE before diagnosis (mortality: pooled relative risk 0.64, 95% CI 0.56-0.73; advanced cancer, pooled relative risk 0.60, 95% CI 0.46-0.80). The results are probably due to bias and confounding. There was no difference in death rate in studies on women who detected their cancer during an examination (pooled relative risk 0.90, 95% CI 0.72-1.12). None of the trials of BSE training (in which most women reported practising it regularly) showed lower mortality in the BSE group (pooled relative risk 1.01, 95% CI 0.92-1.12). They did show that BSE is associated with considerably more women seeking medical advice and having biopsies. Regular BSE is not an effective method of reducing breast cancer mortality.
Pulmonary rehabilitation (PR) programmes produce initial improvements in exercise tolerance and health status in patients with chronic obstructive pulmonary disease (COPD). However, there is limited data on the longer term effects of PR. This study has examined whether the initial benefits gained in exercise tolerance and health status may be maintained after a 1-year follow-up programme. Sixty-six patients with COPD were assessed with the MRC Dyspnoea Scale and found to be moderately disabled due to dyspnoea (MRC Grades 3 and 4). These patients were then randomised to an 8 week outpatient programme of either exercise training and education (Exercise group) or to education alone (Control group). Exercise performance was assessed with the shuttle walking test and health status assessed with two disease-specific measures, the St Georges Respiratory Questionnaire and the Chronic Respiratory Disease Questionnaire. After PR, all patients were invited to attend monthly follow-up sessions for 1 year. Fifty-six patients were available for follow-up immediately after the programme and were assessed at 6 months and 1 year. This study has shown that the patients in the Exercise group maintained improvements in exercise capacity and health status up to 6 months after an 8 week programme. At 1 year there was a significant difference between the Exercise and Control groups in terms of exercise tolerance due to a considerable decline experienced by the Control group. However, neither group had maintained improvements in health status at 1 year. Further study is required to assess whether benefit may be sustained for a longer period using alternative follow-up strategies.
We have previously reported the validity of a new assessment tool; the London Chest Activity of Daily Living Scale (LCADL). This work investigates the reliability and responsiveness of that measure. Reliability was assessed in 19 patients with stable severe chronic obstructive pulmonary disease (COPD); median age (range) 66 (55-79) years, FEV1 mean (SD) 0.91 (0.29) l, by test-retest 4 weeks apart. Responsiveness was assessed in 59 patients; median age (range) 66 (38-84) years, FEV1 mean (SD) 0.87 (0.30) l, who had undergone at least 6 weeks of pulmonary rehabilitation. Test-retest scores of the LCADL showed a strong relationship with one another, Intraclass correlation coefficient Icc=0.93 95%CI (0.82-0.97) demonstrating evidence of good reliability. With the exception of the Domestic component, all domains of the LCADL showed a statistically significant reduction in dyspnoea during ADLs after pulmonary rehabilitation. There was a statistically significant improvement in the total LCADL score (mean difference (95% CI) -5.91 (from -9.23 to -2.60) after rehabilitation. These data support the use of the LCADL as an outcome measure in COPD which is valid, reliable and responsive to change.
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BACKGROUND: Atrial fibrillation (AF) occurs in 20% to 40% of patients after CABG. Identification of patients vulnerable for arrhythmia will allow targeting of those most likely to benefit from prophylactic therapy. The aim of the present study was to evaluate accuracy of a prospectively defined signal-averaged P-wave duration (SAPD) cutoff and additional preoperative characteristics for the prediction of AF after CABG. METHODS AND RESULTS: Patients undergoing elective isolated CABG were recruited to the present prospective study. SAPD was recorded in all patients. Filtered signals from 3 orthogonal leads were combined in a vector analysis, and total SAPD was measured preoperatively. Postoperative in-hospital AF occurred in 92 (28.2%) of 326 patients. Patients who developed AF were older (65.9 versus 61.7 years of age; P<0.0005) and had longer SAPD (158 versus 145 ms; P<0.0005) than non-AF patients. Incidence of AF increased in patients > or =75 years of age and increased progressively throughout the range of SAPD. Stepwise logistic regression analysis of preoperative variables identified that SAPD >155 ms (odds ratio, 5.37; 95% CI, 3.10 to 9.30; P<0.0005), advanced age (odds ratio, 1. 53; 95% CI, 1.26 to 1.86 per 5-year increase in age; P<0.0005), and male sex (odds ratio, 2.88; 95% CI, 1.30 to 6.40; P<0.01) independently predicted AF. Prospectively defined SAPD >155 ms predicted AF with positive and negative predictive accuracy of 49% and 84%, respectively. CONCLUSIONS: A combination of prolonged SAPD, advanced age, and male sex identifies patients at high risk for development of AF after CABG.
Activities of daily living (ADL) may be severely restricted in patients with COPD and assessment requires evaluation of the impact of disability and handicap on daily life. This study is concerned with the development and validation of a standardized 15-item questionnaire to assess routine ADL. Sixty (33 male, 27 female) patients with severe COPD, mean (SD) FEV1 0.91 (0.43) l, median (range) age 70 (50-82) years, completed a 59-item ADL list previously generated by open-ended interview and by literature review. Patients also performed the Shuttle Walk Test (SWT), and completed the St George's Respiratory Questionnaire (SGRQ), the Nottingham Extended Activity of Daily Living Questionnaire (EADL) and the Hospital Anxiety and Depression score (HAD). Criteria for item reduction in the development of The London Chest ADL scale (LCADL) consisted of removal of items where the majority of respondents showed no limitation in the activity (n = 19), where there was no association with perception of global health (n = 9), where an association with age or gender was detected (n = 4), or where items showed poor reliability on test re-test (n = 9). Fifteen items were identified as core activities of daily living. The LCADL was then compared with other measures of health status in these patients. There were good correlations with the SGRQ activity and impact components (p=0.70; P<0.0001) and (p=0.58; P<0.0001), respectively, and EADL (p=0.45; P<0.001), and a moderate correlation with HAD anxiety (p=0.28; P<0.03). There was a significant relationship between the SWT and LCADL (p=0.58; P<0.0001), suggesting a relationship between impaired exercise performance and lower ADL scores. There was evidence of high internal consistency of the questionnaire with Chronbach's alpha of 0.98. These findings suggest that the LCADL scale is a valid tool for the assessment of ADL in patients with severe COPD.
The aim of this study was to determine the effects of different agricultural treatments and plant communities on the diversity of ammonia oxidizer populations in soil. Denaturing gradient gel electrophoresis (DGGE), coupled with specific oligonucleotide probing, was used to analyze 16S rRNA genes of ammonia oxidizers belonging to the beta subgroup of the division Proteobacteria by use of DNA extracted from cultivated, successional, and native deciduous forest soils. Community profiles of the different soil types were compared with nitrification rates and most-probable-number (MPN) counts. Despite significant variation in measured nitrification rates among communities, there were no differences in the DGGE banding profiles of DNAs extracted from these soils. DGGE profiles of DNA extracted from samples of MPN incubations, cultivated at a range of ammonia concentrations, showed the presence of bands not amplified from directly extracted DNA. Nitrosomonas-like bands were seen in the MPN DNA but were not detected in the DNA extracted directly from soils. These bands were detected in some samples taken from MPN incubations carried out with medium containing 1,000 microg of NH(4)(+)-N ml(-1), to the exclusion of bands detected in the native DNA. Cell concentrations of ammonia oxidizers determined by MPN counts were between 10- and 100-fold lower than those determined by competitive PCR (cPCR). Although no differences were seen in ammonia oxidizer MPN counts from the different soil treatments, cPCR revealed higher numbers in fertilized soils. The use of a combination of traditional and molecular methods to investigate the activities and compositions of ammonia oxidizers in soil demonstrates differences in fine-scale compositions among treatments that may be associated with changes in population size and function.
BACKGROUND: Supplemental oxygen in patients with chronic obstructive pulmonary disease (COPD) and exercise hypoxaemia improves exercise capacity and dyspnoea. However, the benefit of oxygen during pulmonary rehabilitation in these patients is still unknown. METHODS: Twenty five patients with stable COPD (mean (SD) forced expiratory volume in one second (FEV(1)) 0.76 (0.29) l and 30.0 (9.89)% predicted, arterial oxygen tension (PaO(2)) 8.46 (1.22) kPa, arterial carbon dioxide tension (PaCO(2)) 6.32 (1.01) kPa) and significant arterial desaturation on exercise (82.0 (10.4)%) were entered onto a pulmonary rehabilitation programme. Patients were randomised to train whilst breathing oxygen (OT) (n = 13) or air (AT) (n = 12), both at 4 l/min. Assessments included exercise tolerance and associated dyspnoea using the shuttle walk test (SWT) and Borg dyspnoea score, health status, mood state, and performance during daily activities. RESULTS: The OT group showed a significant reduction in dyspnoea after rehabilitation compared with the AT group (Borg mean difference -1.46 (95% CI -2.72 to -0.19)) but there were no differences in other outcome measures: SWT difference -23.6 m (95% CI -70.7 to 23.5), Chronic Respiratory Disease Questionnaire 3.67 (95% CI -7.70 to 15.1), Hospital Anxiety and Depression Scale 1. 73 (95% CI -2.32 to 5.78), and London Chest Activity of Daily Living Scale -2.18 (95% CI -7.15 to 2.79). At baseline oxygen significantly improved SWT (mean difference 27.3 m (95% CI 14.7 to 39.8) and dyspnoea (-0.68 (95% CI -1.05 to -0.31)) compared with placebo air. CONCLUSIONS: This study suggests that supplemental oxygen during training does little to enhance exercise tolerance although there is a small benefit in terms of dyspnoea. Patients with severe disabling dyspnoea may find symptomatic relief with supplemental oxygen.
The addition of noninvasive positive pressure ventilation (NPPV) to an exercise training (ET) program in severe chronic obstructive pulmonary disease (COPD) may produce greater benefits in exercise tolerance and quality of life than after training alone. Forty-five patients with severe stable COPD-mean (SD) FEV(1) 0.96 (0.31) L, Pa(O(2)) 65.4 (9.07) mm Hg, Pa(CO(2)) 45.6 (7.89) mm Hg-were randomized to domiciliary NPPV + ET (n = 23) or ET alone (n = 22). Exercise capacity and health status were assessed at baseline and after an 8-wk training program. There was a significant improvement in mean shuttle walk test (SWT) in the NPPV + ET group: from 169 (112) to 269 (124) m (p = 0.001), compared with the ET group: 205 (100) to 233 (123) m (p = 0.19); mean difference (95% confidence interval [CI]): 72 (12.9 to 131) m. Repeated measures analysis of variance (ANOVA) showed that the differences between the two groups became evident only in the final 4 wk of the training program with a mean end study difference (95% 1CI) of 65.8 (17.1 to 114) m. There was a significant improvement in the Chronic Respiratory Disease Questionnaire (CRDQ) of mean (SD) 24.0 (17.4) (p = < 0.001) in the NPPV + ET group and 11.8 (15.8) (p = 0.003) points in the ET group; mean difference: 12.3 (1.19 to 23.4). Only the NPPV + ET group demonstrated a significant improvement in arterial oxygenation; mean difference: 3.70 mm Hg (0.37 to 7.27). This study suggests that domiciliary NPPV can be used successfully to augment the effects of rehabilitation in severe COPD.
BACKGROUND: Respiratory tract infections may acutely increase risk from coronary heart disease (CHD), though the mechanisms have not been defined. Patients with chronic obstructive pulmonary disease (COPD) are prone to repeated exacerbations that are often associated with respiratory infections. These patients also have increased cardiovascular morbidity and mortality. We hypothesized that transient acute increases in plasma fibrinogen, an independent risk factor for CHD, could occur at COPD exacerbation (mediated through a rise in IL6) and thereby provide a mechanism linking respiratory infection to risk of coronary heart disease. METHODS: 93 COPD patients [mean (SD) age 66.8 (8.1) years] were followed regularly over one year, with daily diary card monitoring of respiratory symptoms and peak expiratory flow rate (PEFR); 67 patients [mean FEV1 1.06 (0.44) l, FVC 2.43 (0.79) l] were seen during 120 exacerbations. At each visit spirometry was measured and blood samples taken for plasma fibrinogen and Interleukin-6 (IL-6) levels. RESULT: At baseline, the mean (SD) plasma fibrinogen was elevated at 3.9 (0.67) g/l in the 67 patients with exacerbations during the study and the median (IQR) IL-6 at 4.3 (2.4 to 6.8) pg/ml. Plasma fibrinogen increased by 0.36 (0.74) g/l at exacerbation (p <0.001). with IL-6 levels rising by 1.10 (-2.73 to 6.95) pg/ml (p = 0.008). There was a relation between the changes in fibrinogen at exacerbation and IL-6 levels (r = 0.348, p <0.001). Multiple regression revealed significantly greater rises in fibrinogen when exacerbations were associated with purulent sputum (b = 0.34 g/l; p = 0.03), increased cough (b = 0.31 g/l, p = 0.019) and symptomatic colds (b = 0.228; p = 0.024). CONCLUSIONS: Plasma fibrinogen levels were elevated in stable patients with COPD and may contribute to the increased cardiovascular morbidity and mortality in these patients. COPD exacerbations increased serum IL-6 levels, leading to a rise in plasma fibrinogen. Thus acute rather than chronic infection may have a role in predisposing to coronary heart disease or stroke.
Autotrophic ammonia oxidizer (AAO) populations in soils from native, tilled, and successional treatments at the Kellogg Biological Station Long-Term Ecological Research site in southwestern Michigan were compared to assess effects of disturbance on these bacteria. N fertilization effects on AAO populations were also evaluated with soils from fertilized microplots within the successional treatments. Population structures were characterized by PCR amplification of microbial community DNA with group-specific 16S rRNA gene (rDNA) primers, cloning of PCR products and clone hybridizations with group-specific probes, phylogenetic analysis of partial 16S rDNA sequences, and denaturing gradient gel electrophoresis (DGGE) analysis. Population sizes were estimated by using most-probable-number (MPN) media containing varied concentrations of ammonium sulfate. Tilled soils contained higher numbers than did native soils of culturable AAOs that were less sensitive to different ammonium concentrations in MPN media. Compared to sequences from native soils, partial 16S rDNA sequences from tilled soils were less diverse and grouped exclusively within Nitrosospira cluster 3. Native soils yielded sequences representing three different AAO clusters. Probes for Nitrosospira cluster 3 hybridized with DGGE blots from tilled and fertilized successional soils but not with blots from native or unfertilized successional soils. Hybridization results thus suggested a positive association between the Nitrosospira cluster 3 subgroup and soils amended with inorganic N. DGGE patterns for soils sampled from replicated plots of each treatment were nearly identical for tilled and native soils in both sampling years, indicating spatial and temporal reproducibility based on treatment.
BACKGROUND: Methods of classifying chronic obstructive pulmonary disease (COPD) depend largely upon spirometric measurements but disability is only weakly related to measurements of lung function. With the increased use of pulmonary rehabilitation, a need has been identified for a simple and standardised method of categorising disability in COPD. This study examined the validity of the Medical Research Council (MRC) dyspnoea scale for this purpose. METHODS: One hundred patients with COPD were recruited from an outpatient pulmonary rehabilitation programme. Assessments included the MRC dyspnoea scale, spirometric tests, blood gas tensions, a shuttle walking test, and Borg scores for perceived breathlessness before and after exercise. Health status was assessed using the St George's Respiratory Questionnaire (SGRQ) and Chronic Respiratory Questionnaire (CRQ). The Nottingham Extended Activities of Daily Living (EADL) score and Hospital Anxiety and Depression (HAD) score were also measured. RESULTS: Of the patients studied, 32 were classified as having MRC grade 3 dyspnoea, 34 MRC grade 4 dyspnoea, and 34 MRC grade 5 dyspnoea. Patients with MRC grades 1 and 2 dyspnoea were not included in the study. There was a significant association between MRC grade and shuttle distance, SGRQ and CRQ scores, mood state and EADL. Forced expiratory volume in one second (FEV1) was not associated with MRC grade. Multiple logistic regression showed that the determinants of disability appeared to vary with the level of disability. Between MRC grades 3 and 4 the significant covariates were exercise performance, SGRQ and depression score, whilst between grades 4 and 5 exercise performance and age were the major determinants. CONCLUSIONS: The MRC dyspnoea scale is a simple and valid method of categorising patients with COPD in terms of their disability that could be used to complement FEV1 in the classification of COPD severity.
Exacerbations occur commonly in patients with moderate or severe chronic obstructive pulmonary disease (COPD) but factors affecting their severity and frequency or effects on quality of life are unknown. We measured daily peak expiratory flow rate (PEFR) and daily respiratory symptoms for 1 yr in 70 COPD patients (52 male, 18 female, mean age [+/- SD] 67.5 +/- 8.3 yr, FEV1 1.06 +/- 0.45 L, FVC 2.48 +/- 0.82 L, FEV1/FVC 44 +/- 15%, FEV1 reversibility 6.7 +/- 9.1%, PaO2 8.8 +/- 1.1 kPa). Quality of life was measured by the St. George's Respiratory Questionnaire (SGRQ). Exacerbations (E) were assessed at acute visit (reported exacerbation) or from diary card data each month (unreported exacerbation). In 61 (87%) patients there were 190 exacerbations (median 3; range, 1 to 8) of which 93 (51%) were reported. There were no differences in major symptoms (increase in dyspnea, sputum volume, or purulence) or physiological parameters between reported and unreported exacerbations. At exacerbation, median peak flow fell by an average of 6.6 L/min (p = 0.0003). Using the median number of exacerbations as the cutoff point, patients were classified as infrequent exacerbators (E = 0 to 2) or frequent exacerbators (E = 3 to 8). The SGRQ Total and component scores were significantly worse in the group that had frequent exacerbations: SGRQ Total score (mean difference = 14.8, p < 0.001), Symptoms (23.1, p < 0.001), Activities (12.2, p = 0.003), Impacts (13.9, p = 0.002). However there was no difference between frequent and infrequent exacerbators in the fall in peak flow at exacerbation. Factors predictive of frequent exacerbations were daily cough (p = 0.018), daily wheeze (p = 0.011), and daily cough and sputum (p = 0.009) and frequent exacerbations in the previous year (p = 0.001). These findings suggest that patient quality of life is related to COPD exacerbation frequency.
This study tested the hypothesis that severity of respiratory disability may affect the outcome of pulmonary rehabilitation. In this randomized, controlled study, 126 patients with chronic obstructive pulmonary disease (COPD) were stratified for dyspnoea using the Medical Research Council (MRC) dyspnoea score into MRC3/4 (Moderate) (n=66) and MRC 5 (Severe) dyspnoeic (n=60) groups. The patients were randomly assigned to an eight week programme of either exercise plus education (Exercise group) or education (Control group). Education and exercise programmes for the moderately dyspnoeic patients were carried out in a hospital outpatient setting. Severely dyspnoeic patients were all treated at home. Those in the Exercise group received an individualized training programme. There was a significant improvement in shuttle walking distance in the moderate dyspnoeic group, who received exercise training; baseline (mean+/-SEM) 191+/-22 m, post-rehabilitation 279+/-22 m (p<0.001). There was no improvement in exercise performance in the severely dyspnoeic patients receiving exercise. Neither group of control patients improved. Health status, assessed by the Total Chronic Respiratory Disease Questionnaire score, increased in the moderately dyspnoeic patients receiving exercise from 80+/-18 to 95+/-17 (p<0.0001) after rehabilitation. Much smaller changes were seen in the other three groups. Improvement in exercise performance and health status in patients with chronic obstructive pulmonary disease after an exercise programme depends on the initial degree of dyspnoea.
BACKGROUND: Clinical observations over a 12 year period have suggested a changing pattern of adult respiratory tuberculosis in patients from the Indian subcontinent in two districts of the United Kingdom with a high incidence of tuberculosis. METHODS: Details of all patients for the period 1981-92 residing in the Newham and Blackburn districts aged 15 and over whose ethnic origin was from the Indian subcontinent (n = 1308) were analysed by stepwise logistic regression to determine the relationship between sputum smear positivity, sputum culture positivity, and isolated mediastinal lymphadenopathy, year of notification, age, sex, ethnic group (Indian or Pakistani), and whether the patient had visited the Indian subcontinent within the last three years. RESULTS: The proportion of cases who were smear positive rose over the 12 years of the study, as did the proportion of culture positive cases. The proportion with isolated mediastinal lymphadenopathy fell. These changes took place in both districts. They were not explained by demographic changes in age, sex, or ethnic group, nor was there evidence that smear and culture positivity increased in those who had recently visited India or Pakistan. CONCLUSIONS: The pattern of tuberculosis in adult patients originating from the Indian subcontinent has altered over time towards that seen in the white population in the UK.