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At least 19 recordsLinked to original sources

Oncogenic human papillomavirus infection and cervical lesions in aboriginal women of Nunavut, Canada.

BACKGROUND: The high rate of cervical cancer among aboriginal women of northern Canada has prompted the search for more aggressive methods to augment Papanicolaou (Pap) screening in this population. Nearly all cervical cancers result from oncogenic human papillomavirus (HPV) infections. This has generated interest for incorporating HPV testing into the current screening program. GOALS: To determine the prevalence of oncogenic HPVs in Nunavut, and to assess the association between HPV and squamous intraepithelial lesions (SIL). STUDY DESIGN: A cross-sectional study was conducted on the Pap-screened populations in 19 communities of Nunavut, Canada. Liquid-based cytology was used to screen for SIL. HPV testing was performed using the Hybrid Capture II assay. Correlates of HPV infection and SIL were assessed by logistic regression with control for potential confounders. RESULTS: In 1290 women ages 13 to 79 years, the prevalence rate was 26% for oncogenic HPV and 6.9% for SIL. The odds ratio for the association between HPV and SIL was 37.9 (95% CI, 17.7-80.8) after multivariate adjustment. This association increased markedly with increasing viral load. More than 90% of the women with squamous intraepithelial lesions had positive test results for HPV. More than 75% of the women who had positive test results for HPV but negative test results for SIL were younger than 30 years. CONCLUSION: The results of this study form the basis for further evaluation of the role that liquid-based cytology and HPV testing plays and will contribute to the strategy for cervical cancer prevention in Nunavut.

Adolescent↗

Polychaetes as indicators of environmental disturbance on subarctic tidal flats, Iqaluit, Baffin Island, Nunavut Territory.

The polychaetes of the tidal flats near the town of Iqaluit, Baffin Island were analysed along gradients of environmental disturbance resulting from human activity. Sources of environmental disturbance include a sewage lagoon, garbage sites; and an area of the tidal flat that is cleared by bulldozer. Sampling of the tidal flats included 300 biological sediment cores taken from 75 sites along seven transects. Environmental disturbance has resulted in four zones of polychaete communities with increasing distance. The heavily disturbed zone is closest to the disturbances and is devoid of polychaetes. The disturbed zone follows and is characterized by low diversity the result of increased densities of a few opportunistic species such as, Capitella 'capitata' sp. The moderately disturbed zone is characterized by increased species diversity due to organic enrichment from the disturbances. The undisturbed zone, located the furthest from the sources of disturbance, is characterized by moderate levels of diversity compared to the other three zones.

Animals↗

G-protein beta3 subunit gene splice variant and body fat distribution in Nunavut Inuit.

The GNB3 825T allele encodes a product that has enhanced activation of heterotrimeric G proteins in vitro and could play a role in adipogenesis. We therefore evaluated the possibility that the GNB3 825T allele was associated with obesity in a sample of 213 healthy Canadian Inuit. We found that body weight, body mass index, waist girth, hip girth, subscapular skinfold thickness, and triceps skinfold thickness were significantly higher in subjects with the GNB3 825T/T genotype than in subjects with other genotypes. Furthermore, two anthropometric ratios, namely that of waist to hip circumference and that of subscapular to triceps skinfold thickness, were not significantly different across genotypes. This suggested that the increased deposition of fat in subjects with the GNB3 825T/T genotype was generalized and not localized to particular subregions. There was no association of this genetic variation with blood pressure. The GNB3 825T/T genotype accounted for between 1.6% and 3.3% of the total variation (< or =13% of attributable variation) of the obesity-related traits. The potential for a genetic marker of obesity creates opportunities for future studies in the Inuit, not just to confirm the associations, but also to examine prospectively the influence of interventions and possible relationships between GNB3 825T and longer term complications of obesity.

Adolescent↗

Serologic evidence of influenza A infection in marine mammals of arctic Canada.

A serologic survey of influenza A antibodies was undertaken on 1,611 blood samples from five species of marine mammals collected from Arctic Canada from 1984-98. Sampling was done in 24 locations throughout the Canadian Arctic encompassing Sachs Harbor (72 degrees N, 125 degrees W), Northwest Territories in the west to Loks Land (63 degrees N, 64 degrees W), Nunavut in the east, to Eureka (80 degrees N, 86 degrees W), Nunavut in the north to Sanikiluaq (56 degrees N, 79 degrees W), Nunavut in the south. A competitive ELISA using a monoclonal antibody (Mab) against influenza A nucleoprotein (NP) was used. Five of 418 (1.2%) belugas (Delphinapterus leucas) and 23 of 903 (2.5%) ringed seals (Phoca hispida) were serologically positive. None of the 210 walruses (Odobenus rosmarus rosmarus), 76 narwhals (Monodon monoceros) and four bowhead whales (Balaena mysticetus) had detectable antibodies to influenza A. Positive belugas were identified from communities on southeast Baffin Island while positive ringed seals came from communities in the eastern, western and high Arctic. Virus isolation attempts on lung tissue from a seropositive beluga were unsuccessful. We believe that influenza A infection in marine mammals is sporadic, the infection is probably self-limiting, and it may not be able to be maintained in these animals. Although the predominant hemagglutinin (H) type was not determined and therefore the pathogenicity of the strains to humans is unknown, the hunting and consumption of marine mammals by the Inuit, may put them at risk for influenza A infection.

Animals↗

Prevalence of Toxoplasma gondii antibodies in muskox (Ovibos moschatus) sera from northern Canada.

Prevalence of antibodies to Toxoplasma gondii was determined in 203 muskoxen (Ovibos moschatus) from 3 geographically distinct areas of northern Canada (near the hamlets of Kugluktuk and Cambridge Bay, Nunavut and Holman, Northwest Territories) by the modified agglutination test (MAT). Antibodies were found in 13 (6.4%) of 203 animals with MAT titers of 1:25 in 2, 1:50 in 7, 1:200 in 2, 1:400 in 1, and 1:800 in 1. The 4 muskoxen with MAT titers > or =1:200 were adult females and were among 10 animals examined from a mainland population near Kugluktuk. The seroprevalence was lower in Victoria Island muskoxen collected near Cambridge Bay (4.6% of 151) and Holman (4.8% of 42). This is the first serologic survey for T. gondii infection in muskoxen.

Agglutination Tests↗

Prevalence of Toxoplasma gondii antibodies in barren-ground caribou (Rangifer tarandus groenlandicus) from the Canadian Arctic.

Prevalence of antibodies to Toxoplasma gondii was determined in 147 barren-ground caribou (Rangifer tarandus groenlandicus) from 5 herds in the Northwest Territories and Nunavut, northern Canada, by the modified agglutination test (MAT). In the mainland herds (Bluenose, Bathurst, and Beverly), antibodies were found in 43 (37%) of 117 caribou, and MAT titers were 1:25 in 10, 1:50 in 24, and 1:500 in 9. In the island herds, only 1 (4.3%) of 23 animals sampled from the North Baffin Island herd was positive (titer = 1:25) and no antibodies were detected in 7 caribou from the Dolphin and Union herd. The high prevalence of antibodies to T. gondii in the mainland caribou herds indicates that caribou meat may contain viable T. gondii.

Animals↗

Trace mineral and vitamin concentrations in the liver and serum of wild muskoxen from Victoria Island.

Selected trace minerals and vitamins were assayed in the liver and serum of 25 wild muskoxen (Ovibos moschatus) from Victoria Island, (Nunavut, Canada) in November, 1995. Mean +/- SE liver concentrations in micromol/kg wet weight were 260+/-16 for copper; 1.04+/-0.06 for selenium; 11.5+/-0.7 for molybdenum and 62.8+/-3.3 for vitamin E. Mean +/- SE serum concentrations in micromol/L were 14.2+/-0.3 for copper; 0.75+/-0.04 for selenium, 1.53+/-0.07 for vitamin A and 5.80+/-0.55 for vitamin E. Comparison of liver and serum concentrations of copper, selenium and vitamin E showed that the concentration in one tissue was a relatively poor indicator of the concentration in the other. The copper-molybdenum interaction often seen in domestic species was not observed. In general, the concentrations of metals and vitamins found in muskoxen were comparable to those in other ungulates although serum vitamin E concentrations were about one-fourth of those expected.

Animals↗

Lower respiratory tract infections in Inuit infants on Baffin Island.

BACKGROUND: It has long been suspected that Canadian Inuit children suffer from frequent severe lower respiratory tract infections (LRTIs), but the causes and risk factors have not been documented. This study assessed the infectious causes and other epidemiologic factors that may contribute to the severity of LRTI in young Inuit children on Baffin Island. METHODS: A prospective case study was carried out at the Baffin Regional Hospital in Iqaluit, Nunavut, of infants less than 6 months of age, who were admitted to hospital between October 1997 and June 1998 with a diagnosis of LRTI. Immunofluorescent antibody testing was used to identify respiratory viruses, and enzyme immunoassay (EIA) and polymerase chain reaction (PCR) were used to test for Chlamydia trachomatis. Demographic and risk factor data were obtained through a questionnaire. RESULTS: The annualized incidence rate of admission to hospital for bronchiolitis at Baffin Regional Hospital was 484 per 1000 infants who were less than 6 months of age; 12% of the infants were intubated. Probable pathogens were identified for 18 of the 27 cases considered in our study. A single agent was identified for 14 infants: 8 had respiratory syncytial virus, 2 adenovirus, 1 rhinovirus, 1 influenza A, 1 parainfluenza 3 and 1 had cytomegalovirus. For 4 infants, 2 infectious agents were identified: these were enterovirus and Bordetella pertussis, adenovirus and enterovirus, cytomegalovirus and respiratory syncytial virus, and respiratory syncytial virus and adenovirus. C. trachomatis was not identified by either EIA or PCR. All infants were exposed to maternal smoking in utero, second-hand smoke at home and generally lived in crowded conditions. INTERPRETATION: Inuit infants in the Baffin Region suffer from an extremely high rate of hospital admissions for LRTI. The high frequency and severity of these infections calls for serious public health attention.

Air Pollution, Indoor↗

Genetic prediction of atherosclerosis: lessons from studies in native Canadian populations.

The Oji-Cree from Northern Ontario have a very high prevalence of cardiovascular disease and diabetes mellitus, whereas the Inuit from Nunavut have a very low prevalence of these diseases. There are significant differences between Oji-Cree, Inuit and white subjects with respect to the frequencies of putative 'deleterious alleles' of several candidate genes in diabetes and atherosclerosis. Specifically, compared to whites, both Oji-Cree and Inuit have an excess of 'deleterious alleles' from 12 candidate genes in atherosclerosis and/or diabetes. However, it would appear that these differences in genetic architecture are not sufficient to account for the wide disparity in disease prevalence between the two aboriginal groups. It is very likely that environmental lifestyle factors, such as maintenance of a traditional diet and an increased level of activity, can override an apparent background of genetic susceptibility to these diseases in native people. Full understanding of the genetic component will require more effort because of confounding factors such as small genetic effects, non-mendelian inheritance, gene-gene interactions and gene-environment interactions. However, even before there is a full understanding of the identity of the all the genes involved, and of how their products might contribute to disease susceptibility in an individual or a community, there would be some justification to recommend an intervention strategy at this point in time. Such an intervention strategy would stress a return to a more traditional diet and lifestyle in order to avert and reverse these disease phenotypes in Canadian aboriginal communities.

Arteriosclerosis↗

Weathering of an Arctic oil spill over 20 years: the BIOS experiment revisited. Baffin Island Oil Spill.

A small experimental oil spill was conducted on the northern tip of Baffin Island Nunavut, Canada (72 degrees 31' N, 79 degrees 50' W) in August 1981, and the natural weathering of the oil has been followed by periodic visits. This paper reports on the chemical composition of oil collected in August 2001. The vast majority of the initial oil has gone, but small patches remain. Some samples remain essentially unaltered despite their 20 years of exposure to the elements, while others show that biodegradation and photooxidation can play important roles in removing the majority of the components of the oil. Using 17alpha(H)21beta(H)hopane as a conserved marker within the oil, we show that the most biodegraded sample has lost more than 87% of the hydrocarbons initially present, while another has lost a substantial proportion of its initial chrysene and alkylated congeners. Potential explanations for the different weathering patterns seen in samples collected from this small site are briefly discussed.

Arctic Regions↗

Organochlorine levels in maternal and umbilical cord blood plasma in Arctic Canada.

A baseline for exposure to organochlorine and metal contaminants has been established for mothers and newborns in the Northwest Territories and Nunavut areas of Arctic Canada. Maternal and umbilical cord blood plasma organochlorine levels are described for Inuit, Dene, Métis, Caucasian and Other non-Aboriginal participants. Overall, 523 women volunteered to participate by giving their written informed consent between May 1994 and June 1999, resulting in the collection of 386 maternal blood samples, 407 cord blood samples and 351 maternal/cord pairs. Nearly half of all the participants regularly smoked cigarettes, including 77% of the Inuit participants. Maternal and cord results are presented for PCBs (as Aroclor 1260 and 14 congeners) and organochlorine pesticides, including p,p'-DDT, p,p'-DDE, beta-hexachlorocyclohexane (beta-HCH), hexachlorobenzene (HCB), cis and trans nonachlor, heptachlor epoxide, oxychlordane, mirex, dieldrin and toxaphene. Maternal PCB levels (as Aroclor 1260) averaged 4.42 (+/-9.03) microg/l in Inuit, which was 3.3 times higher than those found in Dene/Métis, and 3.4 times higher than levels in Caucasians. Mean DDE levels were 2.8 times higher in the Other non-Aboriginal group (Chinese, Filipino, East Indian and multiple ethnicity) than in the Inuit group, at 3.99 microg/l and 1.42 microg/l, respectively. Cord blood PCB levels (as Aroclor 1260) averaged 1.16 (+/-2.42) microg/l for Inuit participants, which was 3.3-4 fold higher than the other ethnic groups. PCBs, p,p'-DDE and hexachlorobenzene were detected in all maternal samples, and p,p'-DDE was detected in all cord samples. Regression coefficients for maternal/cord pairs are presented for selected organochlorines. Other results from this study, including maternal and cord metals data, will be presented elsewhere.

Adolescent↗

Field intercomparison studies for evaluation and validation of the AESminiSamplR technique for sampling and analysis of total particulate mercury in the atmosphere.

This paper presents new data and reviews literature results from six field intercomparison studies to further evaluate and validate the AESminiSamplR [Anal. Chem., 70 (1998) 2403] technique for sampling and analysis of total particulate mercury in ambient air. The intercomparison studies were carried out at: two remote sites in the Arctic [Alert, Nunavut, Canada (82 degrees 28'N, 62 degrees 18'W) and Ny-Alesund, Svalbard (78 degrees 54'N, 11 degrees 53'E)], one site in Ann Arbor, MI, and three sites in Europe (one in Italy and two in Sweden). The AESminiSamplR was compared with five other methods using different materials, different flow rates, different sample treatment procedures, and/or different detection techniques. Four of the five methods compared were operated by different laboratories. When the compared methods were operated by different laboratories, a difference </=4 times was observed. When the compared methods were operated by the same laboratory, a maximum deviation of 1.3 times was achieved. These results demonstrate that the AESminiSamplR technique is a reliable, reproducible, simple, fast and cost-effective methodology for sampling and analysis of mercury associated with particulate matter in the atmosphere.

Air Pollutants↗

Contaminant residues in seabird eggs from the Canadian Arctic. Part I. Temporal trends 1975-1998.

Concentrations of total mercury, selenium and a suite of organochlorine compounds were measured in eggs of thick-billed murres (Uria lomvia), northern fulmars (Fulmarus glacialis) and black-legged kittiwakes (Rissa tridactyla) collected on Prince Leopold Island in Lancaster Sound, Nunavut, Canada, between 1975 and 1998. Mercury levels in thick-billed murre and northern fulmar eggs increased significantly during this period while selenium concentrations decreased significantly in northern fulmar eggs. Mercury and selenium concentrations in black-legged kittiwake eggs exhibited no significant temporal trends. Concentrations of sigma PCB, sigma DDT and total chlorobenzenes decreased over time for all three species and there was a shift in the PCB congener pattern as the hexachlorobiphenyl fraction of sigma PCB increased and the lower chlorinated biphenyl fraction decreased. Total chlordane, dieldrin and mirex concentrations decreased in kittiwake eggs while no significant trends were observed for the other two species. Increases in sigma HCH levels were detected in thick-billed murre eggs but not in northern fulmar and black-legged kittiwake eggs. Levels of the beta-HCH isomer, however, increased significantly in murres and fulmars. Stable-nitrogen isotope analyses (delta 15N) indicate that the temporal trends observed for contaminant concentrations in eggs were not the result of shifts in trophic level. Changing deposition patterns of xenobiotic compounds over the summer and winter ranges of these birds provide a likely explanation for differing exposures through time.

Animals↗

The biology of impact craters--a review.

Impact craters contain ecosystems that are often very different from the ecosystems that surround them. On Earth over 150 impact craters have been identified in a wide diversity of biomes. All natural events that can cause localized disruption of ecosystems have quite distinct patterns of rccovery. Impact events are unique in that they are the only extraterrestrial mechanism capable of disrupting an ecosystem locally in space and time. Thus, elucidating the chronological sequence of change at the sites of impacts is of ecological interest. In this synthetic review we use the existing literature, coupled with our own observations at the Haughton impact structure, Devon Island, Nunavut, Canada to consider the patterns of biological recovery at the site of impact craters and the ecological characteristics of impact craters. Three phases of recovery are suggested. The Phase of Thermal Biology, a phase associated with the localized, ephemeral thermal anomaly generated by an impact event. The Phase of Impact Succession and Climax, a phase marked by multiple primary and secondary succession events both in the aquatic realm (impact crater-lakes) and terrestrial realm (colonization of paleolacustrine deposits and impact-generated substrata) that are followed by periods of climax ecology. In the case of large-scale impact events (> 10(4) Mt), this latter phase may also be influenced by successional changes in the global environment. Finally, during the Phase of Ecological Assimilation, the disappearance of the surface geological expression of an impact structure results in a concomitant loss of ecological distinctiveness. In extreme cases, the impact structure is buried. Impact succession displays similarities and differences to succession following other agents of ecological disturbance, particularly volcanism.

Earth, Planet↗

Analysis of "total toxaphene" and selected single congeners in biota by ion trap HRGC-EI-MS/MS using congener-optimized parent ion dissociations.

A method for the quantification of selected toxaphene congeners as well as "total toxaphene" was developed based on electron ionization (EI) tandem (MS/MS) ion trap mass spectrometry (MS) and a combination of fragment ion dissociations. Congeners were separated by high-resolution gas chromatography. Compared to conventional EI low-resolution MS, a 5-20-fold gain in sensitivity could be obtained for octa- or nonachlorinated compounds such as toxaphene #26 and #62 (according to Parlar nomenclature), allowing for their detection in the low picogram range in biota. In addition, response factors for important congeners such as #26, #32, #40/41, #42, #44, #50, and #62 deviated not more than a factor of 2, which is much less as compared to negative ion chemical ionization. This reduces the risk for systematic errors when determining total toxaphene on the basis of a limited number of reference compounds or the technical mixture. Furthermore, chlordanes and polychlorinated biphenyls did not interfere when applying the proposed MS/MS technique. The applicability of the method was tested by determining both total toxaphene and levels of selected congeners in six Arctic wildlife samples collected from Nunavut, Canada, as well as by repetitive analyses of the SRM 1588 certified reference material.

Animals↗

Temporal trends of organochlorine pesticides in the Canadian Arctic atmosphere.

Temperature normalization (TN), multiple linear regression (MLR), and digital filtration (DF) were used to analyze the temporal trends of an atmospheric dataset on organochlorine pesticides (OCs) collected at the Canadian high arctic site of Alert, Nunavut. Details of these techniques have been presented before (Environ. Sci. Technol. 2001, 35, 1303-1311). Both the TN and DF methods revealed that the majority of OC pesticides declined over the 5 years of study, except endosulfan I and several of the pesticide metabolites, including dieldrin and p,p'-DDE. In comparison to studies conducted in the Great Lakes, atmospheric levels in the Arctic were less dependent on temperature, although seasonal variations were apparent. Generally, levels in the winter were lower than during the rest of the year. A notable exception was p,p'-DDE. Many compounds also showed a second minimum in concentrations during June/July and possible explanations are presented to account for this. The estimated first order half-lives for the decline in OC concentrations were generally found to be comparable or slightly longer than those obtained at temperate locations, with the exception of alpha-HCH, which displayed a much longer half-life in the Arctic (approximately 17 yrs). Sporadic increases in heptachlor as well as increases in the ratio of trans- to cis-chlordane suggest episodic input of chlordanes between 1995 and 1997, especially during the winter.

Arctic Regions↗