There was performed an investigation of informativeness of indices of the heart rate variability at rest and during orthostatic testing in the adolescent girls residing in the industrial town and in the village. The influence of unfa- vorable environmental factors was established to be reflected by the indices of the spectral analysis and cardioin- tervalography. In urban girls there was noted the marked increase of the centralization of heart rhythm control on the background of the increased activity of the sympathetic compartment and the reduction of the influence of the parasympathetic compartment of the autonomous nervous system on the sinus node. In rural adolescent girls the func- tional state of the autonomic nervous system being the optimal is characterized by an adequate response to the active orthostatic test of the parasympathetic and sympathetic compartments with the moderate involvement of mechanisms of the central control of the cardiac rhythm. Results of the study have an important significance for the diagnosis of the early disorders of health in adolescent girls.
For the solution of ecological problems in the framework of the preparation of the municipal ecological program in the city of Verkhnyaya Pyshma (Sverdlovskaya Oblast) there was peiformed the assessment of the state of population health, the evaluation of carcinogenic and non-carcinogenic health risk from chemicals that pollute the air and drinking water Atmospheric air was established to be the main environment cause for carcinogenic and non-carcinogenic risks. The obtained results served as the basis for the development of technological, sanitary and hygienical measures of the program aimed at optimizing of the population health.
The Aamjiwnaang First Nations community is located in Canada's 'Chemical Valley' situated in southwest Ontario near Sarnia. Mercury pollution in the region has been known since the 1940s but little is known about levels in the environment and area residents. The current study, using ecological and human exposure assessment methods, was conducted at the community's request to help fill these gaps. First, Canada's National Pollutant Release Inventory and the U.S. Toxics Release Inventory were queried to investigate mercury releases from area facilities. In 2010, 700 pounds of mercury were emitted into the air, 25 pounds were released into water bodies, and 93 thousand pounds were disposed of on-site via underground injections or into landfills, and together these show continued releases into the region. Second, mercury levels were measured in stream sediment and nearby soil from sites at Aamjiwnaang (n = 4) and off Reserve (n = 19) in Canada and the U.S. during three seasons that spanned 2010-2011. Total mercury in sediment across all sites and sampling seasons ranged from 5.0 to 398.7 µg/kg, and in soils ranged from 1.2 to 696.2 µg/kg. Sediment and soil mercury levels at Aamjiwnaang were higher than the reference community, and Aamjiwnaang's Talfourd Creek site had the highest mercury levels. Third, a biomonitoring study was performed with 43 mother-child pairs. Hair (mean ± SD of all participants: 0.18 ± 0.16 µg/g) and blood (1.6 ± 2.0 µg/L) mercury levels did not differ between participants studied on- and off-Reserve, likely because of limited seafood intake (
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Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden (Nyqvist, Helmfrid, Dr Wingren); and Department of Biology and Environmental Science, Faculty of Health and Life Sciences, Linneaus University, Kalmar, Sweden (Dr Augustsson).
The aim of this study was to examine mortality causes and cancer incidence in a population cohort that have resided in close proximity to highly metal-contaminated sources, characterized by contamination of, in particular, arsenic (As), cadmium (Cd), and lead (Pb).
Data from Swedish registers were used to calculate standardized mortality and cancer incidence ratios. An attempt to relate cancer incidence to metal contamination levels was made.
Significantly elevated cancer incidences were observed for overall malignant cancers in both genders, cancer in the digestive system, including colon, rectum, and pancreas, and cancers in prostate among men. Dose-response relationships between Cd and Pb levels in soil and cancer risks were found.
Cancer observations made, together with previous studies of metal uptake in local vegetables, may imply that exposure to local residents have occurred primarily via oral intake of locally produced foodstuffs.
This paper applies a method for modelling the spatial variation of West Nile virus (WNv) in humans using bird, environmental and human testing data.
We used data collected from 503 Alberta municipalities. In order to manage the effects of residual spatial autocorrelation, we used generalized linear mixed models (GLMM) to model the incidence of infection.
There were 275 confirmed cases of WNv in the 2003 calendar year in Alberta. Our spatial model indicates that living in the grasslands natural region and levels of human testing are significant positive predictors of WNv; living in an urban area is a significant negative predictor.
Infected bird data contribute little to our model. The variability of West Nile virus incidence in Alberta may be partly confounded by the variations in the rate of testing in different parts of the province. However, variation in infection is also associated with known environmental risk factors. Our findings are consistent with existing knowledge of WNv in North America.
Development of an effective regulatory system for genetically engineered animals and their products has been the subject of increasing discussion among researchers, industry and policy developers, as well as the public. Since transgenesis and cloning are relatively new scientific techniques, transgenic animals are 'novel' organisms for which there is limited information. The issues associated with the regulation of transgenic animals pertain to environmental impact, human food safety, animal health and welfare, trade and ethics. It is a challenge for the developers to prove the safety of the products of biotechnology-derived animals and also for regulators to regulate this increasingly powerful technology with limited background information. In principle, an effective regulatory sieve should permit safe products while forming a formidable barrier for those posing an unacceptable risk. Regulatory initiatives for biotechnology-derived animals and their products should be able to ensure high standards for human and animal health, a sound scientific basis for evaluation; transparency and public involvement, and maintenance of genetic diversity. This review proposes a regulatory regime that is based on scientific risk based assessment and approval of products or by-products of biotechnology-derived animals and its application in context to Canadian regulations.
In recent years, there has been escalating concern over the possible association between exposure to pesticides and adverse human health effects by a number of non-governmental organizations, professional and public interest groups. Recognizing the need to document the scientific basis of these concerns as a foundation for initiating a research theme devoted to linkages between exposures to pesticides and human health effects, the Canadian Institutes of Health Research (CIHR) requested a summary of recent research trends that address these linkages. Experts across Canada in the field of pesticide regulation and research were invited to participate in the review. The review summarizes the limitations of past and current studies related to pesticides and human health effects research and makes suggestions for future research priorities and proposed study designs that will improve the assessment of pesticide exposure, the associated health risks, and improved methodology for regulatory decision making.
Although the number of Escherichia coli bacteria in surface waters can differ greatly between locations, relatively little is known about the distribution of E. coli pathotypes in surface waters used as sources for drinking or recreation. DNA microarray technology is a suitable tool for this type of study due to its ability to detect high numbers of virulence and antimicrobial resistance genes simultaneously. Pathotype, phylogenetic group, and antimicrobial resistance gene profiles were determined for 308 E. coli isolates from surface water samples collected from diverse aquatic ecosystems at six different sites in the St. Clair River and Detroit River areas. A higher frequency (48%) of E. coli isolates possessing virulence and antimicrobial resistance genes was observed in an urban site located downstream of wastewater effluent outfalls than in the other examined sites (average of 24%). Most E. coli pathotypes were extraintestinal pathogenic E. coli (ExPEC) pathotypes and belonged to phylogenetic groups B2 and D. The ExPEC pathotypes were found to occur across all aquatic ecosystems investigated, including riverine, estuarine, and offshore lake locations. The results of this environmental study using DNA microarrays highlight the widespread distribution of E. coli pathotypes in aquatic ecosystems and the potential public health threat of E. coli pathotypes originating from municipal wastewater sources.
A statistically significant direct strong correlation was found between the annual average daily concentrations of air benz[a]pyrene and the lung and the gastric cancer morbidity rates in males and females, skin, thyroid, and ovarian cancer in females. The certain interval of the measured concentration of benz[a]pyrene and the recorded morbidity rate was shown to be characteristic of each of the above-mentioned tumors.
Incidence of multiple sclerosis is thought to be increasing, but this notion has been difficult to substantiate. In a longitudinal population-based dataset of patients with multiple sclerosis obtained over more than three decades, we did not show a difference in time to diagnosis by sex. We reasoned that if a sex-specific change in incidence was occurring, the female to male sex ratio would serve as a surrogate of incidence change.
Since environmental risk factors seem to act early in life, we calculated sex ratios by birth year in 27 074 Canadian patients with multiple sclerosis identified as part of a longitudinal population-based dataset.
The female to male sex ratio by year of birth has been increasing for at least 50 years and now exceeds 3.2:1 in Canada. Year of birth was a significant predictor for sex ratio (p
Microarray normalizations typically apply methods that assume absence of global transcript shifts, or absence of changes in internal control features such as housekeeping genes. These normalization approaches are not appropriate for focused arrays with small sets of genes where a large portion may be expected to change. Furthermore, many microarrays lack control features that can be used for quality assurance (QA). Here, we describe a novel external control series integrated with a design feature that addresses the above issues.
An EC dilution series that involves spike-in of a single concentration of the A. thaliana chlorophyll synthase gene to hybridize against spotted dilutions (0.000015 to 100 microM) of a single complimentary oligonucleotide representing the gene was developed. The EC series is printed in duplicate within each subgrid of the microarray and covers the full range of signal intensities from background to saturation. The design and placement of the series allows for QA examination of frequently encountered problems in hybridization (e.g., uneven hybridizations) and printing (e.g., cross-spot contamination). Additionally, we demonstrate that the series can be integrated with a LOWESS normalization to improve the detection of differential gene expression (improved sensitivity and predictivity) over LOWESS normalization on its own.
The quality of microarray experiments and the normalization methods used affect the ability to measure accurate changes in gene expression. Novel methods are required for normalization of small focused microarrays, and for incorporating measures of performance and quality. We demonstrate that dilution of oligonucleotides on the microarray itself provides an innovative approach allowing the full dynamic range of the scanner to be covered with a single gene spike-in. The dilution series can be used in a composite normalization to improve detection of differential gene expression and to provide quality control measures.
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Inconsistent results have been obtained from studies that have examined the relationship between air pollution and hospital visits for stroke. We undertook a time-stratified case-crossover study to evaluate associations between outdoor air pollution and emergency department visits for stroke among the elderly according to stroke type, season, and sex. Analyses are based on a total of 12,422 stroke visits among those 65 years of age and older in Edmonton, Canada between April 1, 1992 and March 31, 2002. Daily air pollution levels for SO(2), NO(2), PM(2.5), PM(10), CO and O(3) were estimated using data from fixed-site monitoring stations. Particulate matter data were only available from 1998 onwards. Conditional logistic regression was used to estimate the odds ratios (ORs) and their 95% confidence intervals in relation to an increase in the interquartile range (IQR) of each pollutant. ORs were adjusted for the effects of temperature and relative humidity. We found no association between outdoor measures of air pollution and all stroke visits. In contrast, elevated risks were observed between levels of air pollution and acute ischemic stroke between April and September. During this season, the ORs associated with an increase in the IQR of the 3-day average for CO and NO(2) were 1.32 (95% CI = 1.09-1.60) and 1.26 (95% CI = 1.09-1.46), respectively. CO exposures in the same season, lagged 1 day, were associated with an increased risk of hemorrhagic stroke with ORs was 1.20 (95% CI = 1.00-1.43). Our results suggest it is possible that vehicular traffic, which produces increased levels of NO(2) and CO, contributes to an increased incidence of emergency department visits for stroke.
Patient-related incidents are of particular concern for those working with forensic psychiatric populations. Evidence suggests that personality, stress, and burnout of nursing staff are predictive of incidents. However, the exact relationship of these factors with staff-patient interactions and the incidents that occur within these interactions have not been thoroughly explored. The authors collected data on the nature of incidents on a forensic unit within a psychiatric hospital over a 1-year period, as well as data on the characteristics of 13 staff members. They found that 10% of patients were responsible for 58% of the incidents. Patients with a diagnosis of schizophrenia were disproportionately involved in incidents. The frequency of non-violent incidents varied among nursing teams to an extent greater than that expected by chance. A relationship between incidents and some staff characteristics was also found. These results highlight the need for further research into the incidents that occur in situations where patient attributes, nurse attributes, and environmental factors produce complex interactions.
Exposure to airborne particulate matter has a negative effect on respiratory health in both children and adults. Ultrafine particle (UFP) exposures are of particular concern owing to their enhanced ability to cause oxidative stress and inflammation in the lungs. In this investigation, our objective was to examine the contribution of home heating systems (electric baseboard heaters, wood stoves, forced-air oil/natural gas furnace) to indoor UFP exposures. We conducted a cross-sectional survey in 36 homes in the cities of Montréal, Québec, and Pembroke, Ontario. Real-time measures of indoor UFP concentrations were collected in each home for approximately 14 h, and an outdoor UFP measurement was collected outside each home before indoor sampling. A home-characteristic questionnaire was also administered, and air exchange rates were estimated using carbon dioxide as a tracer gas. Average UFP exposures of 21,594 cm(-3) (95% confidence interval (CI): 14,014, 29,174) and 6660 cm(-3) (95% CI: 4339, 8982) were observed for the evening (1600-2400) and overnight (2400-0800) hours, respectively. In an unadjusted comparison, overnight baseline UFP exposures were significantly greater in homes with electric baseboard heaters as compared to homes using forced-air oil or natural gas furnaces, and homes using wood stoves had significantly greater overnight baseline UFP exposures than homes using forced-air natural gas furnaces. However, in multivariate models, electric oven use (beta=12,253 cm(-3), 95% CI: 3524, 20,982), indoor relative humidity (beta=1136 cm(-3) %, 95% CI: 372, 1899), and indoor smoking (beta=18,192 cm(-3), 95% CI: 2073, 34,311) were the only significant determinants of mean indoor UFP exposure, whereas air exchange rate (beta=4351 cm(-3) h(-1), 95% CI: 1507, 7195) and each 10,000 cm(-3) increase in outdoor UFPs (beta=811 cm(-3), 95% CI: 244,1377) were the only significant determinants of overnight baseline UFP exposures. In general, our findings suggest that home heating systems are not important determinants of indoor UFP exposures.
Physical activity (MVPA) levels during home-based cardiac rehabilitation (CR) remain problematic. Consequently, the present study examined the association between MVPA and urban vs. rural residential status and the perceived environment in patients attending home-based CR. A total of 280 patients completed a questionnaire assessing demographic, clinical, MVPA, and perceived environmental variables measured at baseline and 3 months later. Patient addresses were geocoded and linked to the 2006 Canadian census to establish the urban/rural distinction. Results showed that urban and rural patients had similar baseline MVPA and improvements in MVPA by 3 months. Several perceived environmental variables were significantly related to MVPA throughout home-based CR that were common and urban/rural-specific. Therefore, although there does not appear to be an urban vs. rural advantage in MVPA levels during home-based CR, there does appear to be environmental/MVPA-specific relationships specific to urban and rural patients that may warrant attention.
Fifteen polybrominated diphenyl ethers (PBDEs) and eighteen non-PBDEs were measured in 116 dust samples collected from homes in Vancouver, Canada during 2007-2008 as part of the Chemicals Health and Pregnancy (CHirP) study. The highest concentrations of PBDEs in house dust were observed for BDE 209, with a median concentration of 1350 ng/g. This is about two times greater than the median concentration of the PentaBDE (represented by the most abundant compounds in this formulation, SBDE 47, 99 and 100). In the case of non-PBDE FRs, a detection frequency between 81% and 100% was observed for nine analytes including: HBCD, BTBPE, BEHTBP, EHTBB, HBB, PBTO, PBBe, ATE and DP. The high detection of new FRs in indoor environments reflects their ubiquitous presence in indoor environment due to regulation of the PBDEs. Exposure to FRs are estimated based on these data for adults and toddlers.
Pesticide exposures and immune suppression have been independently associated with the risk of non-Hodgkin lymphoma (NHL), but their joint effect has not been well explored. Data from a case-control study of men from six Canadian provinces were used to evaluate the potential effect modification of asthma, allergies, or asthma and allergies and hay fever combined on NHL risk from use of: (i) any pesticide; (ii) any organochlorine insecticide; (iii) any organophosphate insecticide; (iv) any phenoxy herbicide; (v) selected individual pesticides [1,1'-(2,2,2-trichloroethylidene)bis[4-chlorobenzene]; 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT), malathion, (4-chloro-2-methylphenoxy)acetic acid (MCPA), mecoprop, and (2,4-dichlorophenoxy)acetic acid (2,4-D); and (vi) from the number of potentially carcinogenic pesticides. Incident NHL cases (n = 513) diagnosed between 1991 and 1994 were recruited from provincial cancer registries and hospitalization records and compared to 1,506 controls. A stratified analysis was conducted to calculate odds ratios (ORs) adjusted for age, province, proxy respondent, and diesel oil exposure. Subjects with asthma, allergies, or hay fever had non-significantly elevated risks of NHL associated with use of MCPA (OR = 2.67, 95% confidence interval [CI]: 0.90-7.93) compared to subjects without any of these conditions (OR = 0.81, 95% CI: 0.39-1.70). Conversely, those with asthma, allergies, or hay fever who reported use of malathion had lower risks of NHL (OR = 1.25, 95% CI: 0.69-2.26) versus subjects with none of these conditions (OR = 2.44, 95% CI: 1.65-3.61). Similar effects were observed for asthma and allergies evaluated individually. Although there were some leads regarding effect modification by these immunologic conditions on the association between pesticide use and NHL, small numbers, measurement error and possible recall bias limit interpretation of these results.