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At least 847 records · Page 47Linked to original sources
PubMed2001

Resolving the origin of the petrogenic hydrocarbon background in Prince William Sound, Alaska.

The dominant sources of the petrogenic hydrocarbon background in benthic sediments of Prince William Sound, AK (PWS), site of the 1989 Exxon-Valdez oil spill, are eroding Tertiary shales and residues of natural oil seepage. Mass balance considerations and statistical analyses of hydrocarbon fingerprints independently indicate that coal contributes generally less than 1% of the polycyclic aromatic hydrocarbons (PAH) and chemical biomarkers in this background. This is environmentally significant because of presumed differences in the bioavailability of PAH in coal, seep oil residues, and shales. Coal particles are present in PWS sediments, but their PAH and chemical biomarker contributions are overwhelmed by those of seep oil residues and organic particles from shales of low-to-high thermally maturity. In the late Tertiary or early Quaternary, the currently exposed and eroding shale formations were heated into the oil-generation window and, consequently, are now relatively rich in extractable PAH and chemical biomarkers. The exposed and eroding coals in the area, in contrast, experienced long hot burial and are now thermally overmature with respect to oil generation. The concentrations of thermally sensitive PAH and biomarker compounds in PWS sediments are not consistent with a mature coal origin but are consistent with the low-to-high maturity shales and seep oils in the area.

Alaska↗
PubMed2006

PCBs, PCDD/Fs, and organochlorine pesticides in farmed Atlantic salmon from Maine, eastern Canada, and Norway, and wild salmon from Alaska.

Farmed Atlantic salmon (Salmo salar) from Maine and eastern Canada, wild Alaskan Chinook salmon (Oncorhynchus tshawytscha), and organically farmed Norwegian salmon samples were analyzed for the presence of polychlorinated biphenyls (PCBs), dioxin-like PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), dibenzo-p-furans (PCDFs), and chlorinated pesticides. PCDD and PCDF congeners were not detected in > 80% of the samples analyzed. Total PCB concentrations (7.2-29.5 ng/g, wet weight, ww) in the farmed salmon were significantly higher than those in the wild Alaskan Chinook samples (3.9-8.1 ng/g, ww). Concentrations of PCBs, WHO PCB TEQs, and chlorinated pesticides varied significantly by region. PCB and WHO PCB TEQ concentrations in farmed salmon from eastern Canada were lower than those reported in samples collected two years earlier, possibly reflecting recent industry efforts to lower contaminant concentrations in feed. Organically farmed Norwegian salmon had the highest concentrations of PCBs (mean: 27 ng/g, ww) and WHO PCB TEQs (2.85 pg/g,ww); their TEQ values are in the higher range of those reported in farmed salmon from around the world. Removal of skin from salmon fillets resulted in highly variable reductions of lipids and contaminants, and in some skin-off samples, contaminant levels were higher, suggesting that skin removal does not protect the consumer from health risks associated with consumption of farmed salmon.

Alaska↗
PubMed2001

Preventive care of older urban American Indians and Alaska natives in primary care.

Little is known about prevention among elderly or urban American Indian/Alaska Native (AI/AN) populations. We reviewed the medical records of 550 older urban AI/AN primary care patients to evaluate how frequently preventive measures were received. Adherence to guidelines was examined by a culturally appropriate (> or =50 years) and standard age threshold (> or =65 years), and by performance of preventive measures at any time ("ever") and in the past year. Lifetime performance was inadequate for the many measures, including mammograms (56%), fecal occult blood testing (37%), audiometry (33%), visual acuity testing (50%), smoking cessation counseling (50%), and pneumococcal (22%) and influenza (49%) vaccinations. Performance of the measures was less frequent in the prior year, but did not differ by age threshold. Predictors of adherence included female gender, having insurance, and having more health problems and medications. Nonadherence infrequently resulted from patients' failure to comply with recommendations. We conclude that use of most preventive services among elderly urban AI/ANs is suboptimal and should be improved.

Age Factors↗
PubMed2000

Hepatitis B virions isolated with antibodies to the pre-S1 domain reveal occult viremia by PCR in Alaska Native HBV carriers who have seroconverted.

BACKGROUND: Occult viremia occurring before the appearance of HBsAg or after the disappearance of HBsAg is detectable by gene amplification technologies whose efficiency depends on nucleic acid preparation. STUDY DESIGN AND METHODS: To isolate HBV DNA from viremic plasma, immunoaffinity capture (IAC) of intact HBV with biotinylated pre-S1 antibodies coupled to streptavidin-coated magnetic beads was evaluated. IAC was compared with a silica-gel method (Qiagen [QSG]) and its two modifications wherein the samples were heated with lysis buffer at 60(o)C for 10 minutes (QSG-60) or at 58 degrees C for 60 minutes with proteinase-K (QSG-PK). Each HBV DNA sample was tested by heminested PCR amplification of the HBV gene sequences. A total of 36 coded serum samples were tested, including three HBsAg-positive controls and 33 former chronic HBV carriers who had seroconverted (developed antibody to HBsAg [anti-HBs]). Commercially available seroconversion panels (PHM 907, 911, and 922) were similarly tested for window-period viremia. RESULTS: In the 33 former chronic HBV carriers who had seroconverted, IAC revealed HBV DNA in 17 samples, whereas it was revealed in only 11 samples by QSG-PK (p = 0.031), 10 by QSG-60 (p = 0.016), and 9 by QSG (p = 0.0078). However, HBV DNA was not amplified from the 17 samples at 1-in-10 dilutions; thus, they were considered to have low-level viremia. IAC revealed HBV DNA as early as or earlier than the other methods in PHM 907, 911, and 922 panels. CONCLUSION: IAC is apparently an optimal method of sample preparation for amplification of HBV DNA in patients in the pre-HBsAg window period, and for detecting low-level viremia persistent in several individuals who were former chronic HBV carriers who had seroconverted (developed anti-HBs).

Alaska↗
PubMed1990

The ecology of Echinococcus multilocularis (Cestoda: Taeniidae) on St. Lawrence Island, Alaska. II. Helminth populations in the definitive host.

The helminths of 1,579 arctic foxes from St. Lawrence Island were investigated by standard methods. The foxes, obtained mainly during the winter from fur trappers, harbored 22 species of helminths. Four of those were trematodes, viz., Maritrema afanassjewi Belopol'skaia, 1952, Orthosplanchnus pygmaeus Iurakhno, 1967, Plagiorchis elegans (Rudolphi, 1802) and Alaria marcianae (LaRue, 1917), each of which occurred in a single host. Two species of cestodes, Diphyllobothrium dendriticum (Nitzsch, 1824) and Mesocestoides kirbyi Chandler, 1940, were uncommon (in 2.7 and 1.3% of the foxes, respectively). Taenia polyacantha Leuckart, 1856 and Echinococcus multilocularis Leuckart, 1863 were present in about 80% of the foxes, and Taenia crassiceps (Zeder, 1800) in less than 10%. The specimens of Taenia spp. from the autumn-winter sample were usually destrobilate. In about 2% of the foxes, acanthocephalans of six species occurred. Four of those, of the genus Corynosoma Lühe, 1904, were common in marine mammals of the region; a fifth, Corynosoma clavatum Goss, 1940, has been reported previously only from marine birds of the Southern Hemisphere; and the sixth, Polymorphus cf. minutus (Goeze, 1782), has been found widely in waterfowl of the Northern Hemisphere. Of the nematodes, Sobolophyme baturini Petrov, 1930, Cylicospirura felineus (Chandler, 1925), and Physaloptera sp. were rare (with each in only one to three foxes). Trichinella nativa Boev et Britov, 1972 and Crenosoma vulpis (Dujardin, 1844) were uncommon (1.5 and 4%, respectively). The nematodes most often present were Toxascaris leonina (von Linstow, 1902) (89%) and Uncinaria stenocephala (Railliet, 1884) (40%). Several of the rare to uncommon helminths probably were transported to the island by foxes immigrating from the adjacent continents via the pack ice.

Acanthocephala↗
PubMed1990

A programme to reduce the risk of infection by Echinococcus multilocularis: the use of praziquantel to control the cestode in a village in the hyperendemic region of Alaska.

This paper reports the results of a 10-year field trial designed to reduce the risk of infection by Echinococcus multilocularis to residents of a village in a hyperendemic area (Savoonga, St. Lawrence Island). The objective was to prevent dispersal of infective eggs of the cestode within the village by means of monthly treatments of dogs with praziquantel. Northern voles, Microtus oeconomus, present in the village as commensals, served as an index of risk, as the incidence of infection in the voles provides information about the availability of eggs within the confines of the inhabited area. Voles were examined annually during early June before the population of overwintering voles was diluted by the first annual litters. The pretreatment infection-rate within the village was 29% (range 22-35%), and in control areas at some distance from the village for the entire study period it averaged 53% (284 infected voles from a sample of 533). Some fluctuation in incidence of infection in village voles occurred, apparently depending on the extent to which the residents kept their dogs chained and thus available for treatment. The success of the programme was demonstrated by the reduction in prevalence of infection to about 1% of voles in 1985, and an average infection rate during the last five years of the study of 5% (29 infected voles in a sample of 582). This 83% average reduction in the prevalence of the larval cestode within the village reflects a corresponding reduction in the risk of acquiring by the residents of the village. The method would be applicable for the control of E. multilocularis in most hyperendemic regions. Success depends, however, on elimination of unrestrained dogs and a precise schedule of treatment.

Alaska↗