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PubMed2002

Molecular analysis of Dehalococcoides 16S ribosomal DNA from chloroethene-contaminated sites throughout North America and Europe.

The environmental distribution of Dehalococcoides group organisms and their association with chloroethene-contaminated sites were examined. Samples from 24 chloroethene-dechlorinating sites scattered throughout North America and Europe were tested for the presence of members of the Dehalococcoides group by using a PCR assay developed to detect Dehalococcoides 16S rRNA gene (rDNA) sequences. Sequences identified by sequence analysis as sequences of members of the Dehalococcoides group were detected at 21 sites. Full dechlorination of chloroethenes to ethene occurred at these sites. Dehalococcoides sequences were not detected in samples from three sites at which partial dechlorination of chloroethenes occurred, where dechlorination appeared to stop at 1,2-cis-dichloroethene. Phylogenetic analysis of the 16S rDNA amplicons confirmed that Dehalococcoides sequences formed a unique 16S rDNA group. These 16S rDNA sequences were divided into three subgroups based on specific base substitution patterns in variable regions 2 and 6 of the Dehalococcoides 16S rDNA sequence. Analyses also demonstrated that specific base substitution patterns were signature patterns. The specific base substitutions distinguished the three sequence subgroups phylogenetically. These results demonstrated that members of the Dehalococcoides group are widely distributed in nature and can be found in a variety of geological formations and in different climatic zones. Furthermore, the association of these organisms with full dechlorination of chloroethenes suggests that they are promising candidates for engineered bioremediation and may be important contributors to natural attenuation of chloroethenes.

Bacteria, Anaerobic↗
PubMed2004

Development of a new serological test for serotyping Haemophilus parasuis isolates and determination of their prevalence in North America.

Haemophilus parasuis causes polyserositis in swine. Fifteen serovars have been characterized by immunodiffusion test, but many field strains are not typeable. Isolates (n = 300) of H. parasuis from animals in North America were serotyped by a new indirect hemagglutination test. The test was rapid and effective for serotyping of H. parasuis, and serovars 4, 5, 13, and 7 were the most prevalent serotypes.

Animals↗
PubMed1997

High-precision 40Ar/39Ar geochronology and the advent of North America's Late Cretaceous terrestrial fauna.

A densely sampled, diverse new fauna from the uppermost Cedar Mountain Formation, Utah, indicates that the basic pattern of faunal composition for the Late Cretaceous of North America was already established by the Albian-Cenomanian boundary. Multiple, concordant 40Ar/39Ar determinations from a volcanic ash associated with the fauna have an average age of 98.39 +/- 0.07 million years. The fauna of the Cedar Mountain Formation records the first global appearance of hadrosaurid dinosaurs, advanced lizard (e.g., Helodermatidae), and mammal (e.g., Marsupialia) groups, and the first North American appearance of other taxa such as tyrannosaurids, pachycephalosaurs, and snakes. Although the origin of many groups is unclear, combined biostratigraphic and phylogenetic evidence suggests an Old World, specifically Asian, origin for some of the taxa, an hypothesis that is consistent with existing evidence from tectonics and marine invertebrates. Large-bodied herbivores are mainly represented by low-level browsers, ornithopod dinosaurs, whose radiations have been hypothesized to be related to the initial diversification of angiosperm plants. Diversity at the largest body sizes (>10(6) g) is low, in contrast to both preceding and succeeding faunas; sauropods, which underwent demise in the Northern hemisphere coincident with the radiation of angiosperms, apparently went temporarily unreplaced by other megaherbivores. Morphologic and taxonomic diversity among small, omnivorous mammals, multituberculates, is also low. A later apparent increase in diversity occurred during the Campanian, coincident with the appearance of major fruit types among angiosperms, suggesting the possibility of adaptive response to new resources.

Animals↗
PubMed1997

Development of a polymerase chain reaction assay for differentiation between Culex pipiens pipiens and Cx. p. quinquefasciatus (Diptera: Culicidae) in North America based on genomic differences identified by subtractive hybridization.

Culex pipiens is a complex of mosquitoes that are involved in the transmission of pathogens, including St. Louis encephalitis virus in North America. The 2 major taxa in the complex, Cx. p. pipiens and Cx. p. quinquefasciatus, are nearly identical morphologically, making identification of field-collected specimens difficult, and attempts at differentiation based on biochemical and molecular techniques have been unsuccessful. We report here the use of genomic subtractive hybridization to identify a region of nucleic acid heterology between the genomes of Cx. p. pipiens and Cx. p. quinquefasciatus and the development of a polymerase chain reaction (PCR) assay to discriminate between them. PCR primers based on the nucleic acid sequence of a Cx. p. pipiens-unique DNA fragment were used to differentiate Cx. p. pipiens and Cx. p. pipiens/quinquefasciatus hybrids from Cx. p. quinquefasciatus by using extracted individual mosquito genomic DNA, crude DNA preparations from a mosquito head or legs, and DNA from triturated mosquito pools.

Animals↗
PubMedDate not supplied

Pasteurella multocida isolated from wild birds of North America: a serotype and DNA fingerprint study of isolates from 1978 to 1993.

Serotype and DNA fingerprint methods were used to study Pasteurella multocida isolated from 320 wild birds of North America. Isolates were collected during 1978-93. The HhaI profiles of 314 isolates matched the HhaI profile of somatic reference type 1, stain X-73; somatic type 1 antigen was expressed by 310 isolates, and the serotype of four isolates was undetected. Differentiation of the 314 isolates was observed by digestion of DNA with HpaI. None of the HpaII profiles matched the HpaII profile of X-73 (designated HhaI 001/HpaII 001). Three HpaII profiles were recognized among the somatic type 1 isolates: HpaII 002 (n = 18), HpaII 003 (n = 122), and HpaII 004 (n = 174). Profile HpaII 002 was found among isolates collected during 1979-83. Profile HpaII 003 was identified from isolates collected during 1979-89, with the exception of two isolates in 1992. The HpaII 004 profile was identified from isolates collected during 1983-93. Of the six remaining isolates, four expressed somatic type 4 and had HhaI profiles identical to the somatic type 4 reference strain P-1662 profile (designated HhaI 004); these isolates were differentiated by digestion of DNA with HpaII. One isolate was identified as serotype F:11, and another was serotype A:3,4. In the present study, 314 of 316 (99.4%) isolates from wild birds in the Central, Mississippi, and Pacific flyways during 1978-93, were P. multocida somatic type 1.

Animals↗
PubMed1972

Variation in cardiac glycoside content of monarch butterflies from natural populations in eastern North America.

A new spectrophotometric assay has been used to determine the gross concentration of cardiac glycoside in individual monarch butterflies. Adults sampled during the fall migration in four areas of eastern North America exhibited a wide variation in cardiac glycoside concentration. The correlation between spectrophotometrically measured concentrations and emetic dose determinations supports the existence of a broad palatability spectrum in wild monarch butterflies. The cardiac gylcoside concentration is greater in females than in males and is independent of the dry weight of the butterflies; contrary to prediction, both the concentration mean and variance decrease southward. The defensive advantage of incorporating cardiac glycosides may be balanced by detrimental effects on individual viability.

Analysis of Variance↗
PubMed1991

The relative sizes and asymmetry of kidneys in passerine birds from Australia and North America.

Despite their close taxonomic affinities, nectar-feeding passerine birds from Australia had smaller kidneys, on average, than sympatric passerines of equivalent weight that fed entirely upon insects. Insectivorous passerines from North America had larger kidneys, on average, than comparable insect-feeding passerines from the separate endemic radiation in Australia. Dietary and other environmental differences, rather than phylogenetic origins, may account for these differences. The left kidney of Australian passerines was significantly longer, on average, than the right. Kidney widths showed no lateral asymmetry.

Animals↗
PubMed2001

Genomic sequencing of deer tick virus and phylogeny of powassan-related viruses of North America.

Powassan (POW) virus is responsible for central nervous system infection in humans in North America and the eastern parts of Russia. Recently, a new flavivirus, deer tick (DT) virus, related to POW virus was isolated in the United States, but neither its pathogenic potential in human nor the taxonomic relationship with POW virus has been elucidated. In this study, we obtained the near-full-length genomic sequence of the DT virus and complete sequences of 3 genomic regions of 15 strains of POW-related virus strains. The phylogeny revealed 2 lineages, one of which had the prototype POW virus and the other DT virus. Both lineages can cause central nervous system infection in humans. By use of the combination of molecular definition of virus species within the genus Flavivirus and serological distinction in a 2-way cross-neutralization test, the lineage of DT virus is classified as a distinct genotype of POW virus.

3' Untranslated Regions↗
PubMed1967

Radiocarbon dating and archeology in North America.

The history of the development of a radiocarbon chronology shows how the establishment of the times of events and the order of them has greatly improved the understanding of prehistory in North America. This is true also of other parts of the world. Too little has been said of existing discordance between archeologically determined sequences, and interregional associations, and the radiocarbon chronology. It does appear that these will be resolved as additional dates are added and as the results become more finely calibrated so that secular variations may be accounted for. The collaborative aspect of the venture was apparent at the outset. Nevertheless no one expects an archeologist to delve into nuclear physics and geochemistry, and vice versa. There is great need, nevertheless, for the man in the laboratory to comprehend the difficulties of sample collecting and of judgement of the significance of the source of organic matter to be dated. At the same time, the archeologist must become more familiar with the importance of the various steps in the processing of the sample and with, what is most vital, interpretation of the significance of the numbers that appear on the counters.

Archaeology↗
PubMed2006

A cytological study on Kelloggia (Rubiaceae), an intercontinental disjunct genus between eastern Asia and western North America.

A cytological study was carried out for the first time on four populations of the only two species of Kelloggia (Rubiaceae), which occur disjunctly in eastern Asia (K. chinensis Franch.) and western North America (K. galioides Torr.). The consistent mitotic prophase chromosome condensation pattern and interphase nuclei type were determined for both species. The chromosome base number of the genus is suggested to be x = 11. The karyotype of 2n = 22 = 2x = 16m + 6sm was examined for both species. The karyotypical asymmetry of 1A and 2A was found in K. chinensis and K. galioides, respectively. According to the predominant evolutionary direction of karyotype asymmetry in angiosperms, K. galioides (2A) seems slightly more evolved than K. chinensis (1A). Our finding is consistent with the hypothesis of the Old World origin of Kelloggia based on molecular study.

Biological Evolution↗
PubMed1992

The crack cocaine problem. A warning from North America.

This article describes crack cocaine and its adverse clinical and public health effects. Although crack cocaine does not yet constitute a major drug problem in the Nordic countries, heed should be paid to North America where crack cocaine has developed into a serious and widespread problem only a few years after its introduction. In spite of highly publicized efforts to limit its spread, after a small decline in 1990, the use of crack cocaine is once again increasing. Strong efforts should therefore be made to keep this substance away from the Nordic countries.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Integrative oncology in North America.

Integrative oncology is an evolving evidence-based specialty that uses complementary therapies in concert with medical treatment to enhance its efficacy, improve symptom control, alleviate patient distress and reduce suffering. In North America the evolution of research into complementary therapies was delayed by the narrow focus of the Flexner Report. A government-funded research agenda and incorporation of complementary therapies into medical school curricula have been driven by early evidence of efficacy and patient demand. Integrative oncology focuses on the role of natural health products (botanicals, vitamins, and minerals), nutrition, acupuncture, meditation and other mind-body approaches, music therapy, touch therapies, fitness therapies, and more. Some natural health products, such as herbs and their constituent phytochemicals, may be biologic response modifiers that could increase cancer control. Current research stretches from the laboratory to health services. Institutions are exploring the effectiveness gap in their clinical services and are determining efficacy of complementary therapies through randomized controlled trials. Eventually, the goal is to establish practice guidelines through determining relative effectiveness and value through cost-utility studies. The aim of integrative oncology should be one medicine, not alternative; it should be patient-focused; it should be evidence-based; and it should provide the best care for cancer cure, prevention, symptom control, and quality of life.

Complementary Therapies↗
PubMed2001

A 400-year tree-ring chronology from the tropical treeline of North America.

High-elevation sites in the tropics may be particularly sensitive to rapid climate change. By sampling treeline populations, I have developed the first extensive (> 300 years) tree-ring chronology in tropical North America. The site is Nevado de Colima, at the western end of the Mexican Neovolcanic Belt, and the species studied is Mexican mountain pine (Pinus hartwegii). Despite past logging in the area, 300 to 500-year old pines were found at 3600-3700 m elevation, about 300 m below the present treeline. The Nevado de Colima tree-ring chronology is well replicated from 1600 to 1997. Calibration with Colima climatic records points to summer monsoon precipitation as the strongest dendroclimatic signal. Most trees also exhibit extremely low growth in 1913 and 1914, following the January 1913 Plinian eruption of the Volcan de Colima. Because P. hartwegii is found on top of high mountains from Mexico to Guatemala, there is potential for developing a network of tropical treeline chronologies.

Cycadopsida↗
PubMed1989

Evaluation of an atypical HIV type 1 antibody. Serologic pattern leading to detection of HIV type 2 infection in North America.

The variability and discordance of human immunodeficiency virus type 1 (HIV-1) antibody enzyme immunoassay determinations on serial specimens derived, to our knowledge, from the first documented case of HIV-2 infection in North America are described. The initial specimen was weakly reactive, but two subsequent serum specimens were both nonreactive by enzyme immunoassay. All specimens were indeterminate for HIV-1 antibody by HIV-1 Western blot analysis. Serum HIV-2 antibody was demonstrated by enzyme immunoassay using whole virus lysate, HIV-2-specific synthetic peptide assays, and HIV-2 Western blot analysis. Human immunodeficiency virus type 2 genomic sequences were demonstrated in peripheral blood mononuclear cells using gene amplification technology. Human immunodeficiency virus type 2, isolated from peripheral blood lymphocytes, had typical morphologic features of lenti-virus by electron microscopy. Western blot analysis and other specific assays should be considered in individuals with clinical evidence suggesting HIV infection who are nonreactive for HIV-1 antibody by enzyme immunoassay or who have atypical reactivity patterns.

Acquired Immunodeficiency Syndrome↗
PubMed2004

Survey of bandage lens use in North America, October-December 2002.

PURPOSE: The purpose of this work was to report the findings of a survey of current modes of bandage lens (BL) use by optometrists and ophthalmologists in Canada and the United States in 2002. METHODS: Two thousand voluntary surveys were sent to ophthalmic practitioners across the United States and Canada. The survey contained a questionnaire with 15 questions about the practitioner's background and BL-prescribing trends and views. It also contained a 10-patient list with parameters such as patient profile, BL type, and pharmaceutical use. RESULTS: Seventy-two percent of those opthalmic practitioners who returned surveys have prescribed soft contact lenses for therapeutic purposes. BLs are most often used for corneal wound healing and for managing postoperative complications. Pharmaceuticals are concomitantly administered in more than 81% of the patients treated with BLs. The most commonly prescribed pharmaceuticals are antibiotics (47.5% of patients) and antiinflammatory drugs (42% of patients). ACUVUE and Focus Night & Day lenses are the most popular choices for BLs. Most respondents (93%), regardless of whether they routinely prescribed BLs, would be interested in a BL that could deliver a topical pharmaceutical drug. CONCLUSIONS: The results from the survey indicated that BL use is prevalent across North America. The BL-prescribing habits of North American practitioners indicate that there is a strong interest and need for a drug-delivering therapeutic soft contact lens.

Contact Lenses, Hydrophilic↗
PubMed1999

Diagnostic genetic markers and evolutionary relationships among invasive dreissenoid and corbiculoid bivalves in North America: phylogenetic signal from mitochondrial 16S rDNA.

Diagnostic genetic markers from 486 aligned nucleotide sequences of mitochondrial 16S ribosomal DNA were developed for the four closely related species of dreissenoid and corbiculoid bivalves that have invaded North America; the zebra mussel Dreissena polymorpha, the quagga mussel D. bugensis, and the dark false mussel Mytilopsis leucophaeata of the superfamily Dreissenoidea, and the Asian clam Corbicula fluminea of the sister superfamily Corbiculoidea. Evolutionary relationships were examined among the four genera and comparisons were made with native Eurasian populations of D. polymorpha and D. bugensis. Tests were conducted for gender-specific mitochondrial lineages, which occur in some other bivalves. Genetic variability and divergence rates were tested between stem (paired) and loop (unpaired) regions of secondary structure. There were 251 variable nucleotide sites, of which 99 were phylogenetically informative. Overall transition to transversion ratio was 0.76:1.00 and both accumulated linearly in stem and loop regions, suggesting appropriate phylogenetic signal. Genetic distance calibration with the fossil record estimated the pairwise sequence divergence as 0. 0057 +/- 0.0004 per million years. Mytilopsis and Dreissena appear to have diverged about 20.7 +/- 2.7 million years ago. D. bugensis and D. polymorpha appear separated by about 13.2 +/- 2.2 million years. No intraspecific variation was found, including between Eurasian and North American populations, among shallow and deep morphotypes of D. bugensis and between the sexes. Restriction endonuclease markers were developed to distinguish among the species at all life history stages, allowing rapid identification in areas of sympatric distribution.

Animals↗
PubMedDate not supplied

Wasatchian-Bridgerian (Eocene) paleoecology of the western interior of North America: changing paleoenvironments and taxonomic composition of omomyid (Tarsiiformes) primates.

Many changes in mammalian faunas occurred across the early (Wasatchian) to middle (Bridgerian) Eocene boundary as documented in the fossil record from the Western Interior of North America. One of the more striking changes took place within the tarsiiform primate family Omomyidae. In the early Eocene, omomyids were dominated, both in abundance and diversity, by the subfamily Anaptomorphinae. In the middle Eocene, the subfamily Omomyinae dominated in abundance, while both subfamilies were nearly equally diverse. Examination of a series of paleoecological indicators including leaf-margin analysis, cenogram analysis, ecological diversity analysis of trophic structure, the distribution and development of ancient soil horizons (paleosols), and the distribution of lacustrine and fluvial facies in the Bighorn and southern Green River basins of Wyoming reveals factors that may have influenced the composition of omomyid primates. Subtle but important changes occurred in paleoclimates with mean annual temperatures reaching Cenozoic maximums at the end of the Wasatchian into the early Bridgerian. Both land mammal ages were typified by subtropical, closed forested conditions, but the Bridgerian was probably more humid and wetter than the Wasatchian. Paleohabitats most commonly sampled in the Wasatchian of the Bighorn Basin are proximal and distal floodplains, while those of the Bridgerian in the southern Green River Basin are lake margins and proximal floodplains. Changes in paleoclimate may have triggered a wave of omomyine immigration near the end of the Wasatchian with omomyines entering into habitats previously occupied by anaptomorphines. Lake margin and proximal floodplain habitats are those most commonly occupied by omomyines in the Bridgerian with anaptomorphines being more common in basin margin and distal floodplain areas not commonly sampled. Omomyine immigration and sampling of differing paleohabitats are two possible explanations for the changes documented in omomyid diversity and abundance.

Animals↗
PubMed1988

Tree decline in North America.

Air-borne, phytotoxic pollutants are known to adversely affect forest tree growth in North America. On a local scale, exposure to high concentrations of toxic gases, such as sulphur dioxide and fluoride, result in foliar injury, branch dieback, reduced radial growth and increased mortality in a variety of tree species. On a regional scale, the photochemical oxidant, ozone, is responsible for growth decline of pollutant-sensitive eastern white pine genotypes in the eastern United States, and of ponderosa and Jeffrey pines in the mountains of southern and central California. The etiology associated with the reported declines of high elevation red spruce in the Appalachian Mountains and of sugar maple in the northeastern United States and southeastern Canada is incompletely known at present. A complex of predisposing and inciting factors, including temperature and moisture stress, edaphic conditions, aluminium toxicity, insect depredation, and air-borne pollutants are probably involved in these declines.

Journal Article↗