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PubMed1999

Species of Proteocephalus Weinland, 1858 (Cestoda: Proteocephalidae) from cyprinid fishes in North America.

A taxonomic study of Proteocephalus species parasitizing cyprinid fishes in North America, namely Proteocephalus ptychocheilus Faust, 1920 and Proteocephalus cobraeformis Haderlie, 1953, has demonstrated their conspecificity with Proteocephalus torulosus (Batsch, 1786), a common parasite of cypriniform fishes (Cyprinidae and Cobitidae) in the Palaearctic Region. Proteocephalus ptychocheilus and P. cobraeformis are considered junior synonyms of P. torulosus.

Animals↗
PubMed1976

Affinities of Teilhardina (Primates, Omomyidae) with description of a new species from North America.

Teilhardina is a fifth primate found in Early Tertiary rocks of both Europe and North America. Both T. belgica and the new North American species are anaptomorphines; however, neither species is ideally suited for the ancestry of the New World Omomyidae. Pelycodus and the Adapidae are not closely related to Teilhardina and Torrejonian Palenochtha is probably not in the ancestry of omomyids. A combination of dental characters in earliest Anemorhysis suggest this primate is the most generalised known omomyid.

Animals↗
PubMed2001

Epidemiological aspects of irritable bowel syndrome in Europe and North America.

The epidemiology of irritable bowel syndrome (IBS) in Europe and North America was analyzed from published material. The percentage of the population of Western civilisation with IBS symptoms is between 10 and 15% in most studies. The proportion of a Western population visiting a doctor for IBS symptoms is around 5%. The prevalence of IBS and the proportion of consulters do not seem to depend on age in an adult population. The female-to-male ratio of IBS in the population is close to 2. It is higher in IBS consulters in primary care and may be as high as 3 or 4 in tertiary referral centers. At least in patients from these centers, the number of physician visits and colonoscopies is considerable. Most of the consulters get a drug prescription.

Colonic Diseases, Functional↗
PubMed2005

Clustering of contact zones, hybrid zones, and phylogeographic breaks in North America.

A recent test for the existence of suture zones in North America, based on hybrid zones studied since 1970, found support for only two of the 13 suture zones identified by Remington in 1968 (Swenson and Howard 2004). One limitation of that recent study was the relatively small number of hybrid zones available for mapping. In this study, we search for evidence of clustering of contact zones between closely related taxa using data not only from hybrid zones but from species range maps of trees, birds, and mammals and from the position of phylogeographic breaks within species. Digital geographic range maps and a geographic information system approach allowed for accurate and rapid mapping of distributional data. Areas of contact between closely related species and phylogeographic breaks within species clustered into areas characterized by common physiographic features or predicted by previously hypothesized glacial refugia. The results underscore the general importance of geographic barriers to dispersal (mountain chains) and climate change (periods of cooling alternating with periods of warming, which lead to the contraction and expansion of species ranges) in species evolution.

Geography↗
PubMed2004

Current patterns of propofol use in PICU in the United Kingdom and North America.

BACKGROUND: Our aim was to investigate the current patterns of propofol use in pediatric intensive care units (PICUs) in the UK and North America. METHODS: An electronic questionnaire was sent to all PICUs in the UK and those units offering PICU training fellowships in the USA and Canada. RESULTS: We received responses from 15 UK units (75%) and 33 units in North America (52%). Of units who responded, 47% of UK units used propofol for ongoing sedation, compared with 61% of North American units. Units tended to use propofol in defined clinical circumstances, in limited doses, in older children and for relatively short periods. Propofol was used for sedation during procedures in 100% of units although 35% of UK units said that they would use it less frequently in this setting than in the past. Only 18% of North American Units reported that they would be less likely to use propofol for procedures than in the past. CONCLUSIONS: Despite clear guidance from the UK Committee on Safety of Medicines, propofol was still used for ongoing sedation in 47% of UK PICUs responding to our questionnaire. Reasons for this include the utility of the agent and its licensing for use in maintaining anesthesia in children over 3 years, but not for sedation in PICU in similar doses, for similar periods, in the same group of children.

Data Collection↗
PubMed2005

Decoupled taxonomic radiation and ecological expansion of open-habitat grasses in the Cenozoic of North America.

Because of a dearth of Cenozoic grass fossils, the timing of the taxonomic diversification of modern subclades within the grass family (Poaceae) and the rise to ecological dominance of open-habitat grasses remain obscure. Here, I present data from 99 Eocene to Miocene phytolith assemblages from the North American continental interior (Colorado, Nebraska, Wyoming, and Montana/Idaho), constituting the only high-resolution mid-Cenozoic record of grasses. Analyses of these assemblages show that open-habitat grasses had undergone considerable taxonomic diversification by the earliest Oligocene (34 million years ago) but that they did not become ecologically dominant in North America until 7-11 million years later (Late Oligocene or Early Miocene). This pattern of decoupling suggests that environmental changes (e.g., climate changes), rather than taxonomic radiations within Poaceae, provided the key opportunity for open-habitat grasses to expand in North America.

Demography↗
PubMed1999

Continental drainage in north america during the phanerozoic from Nd isotopes

Neodymium (Nd) isotopic data show consistent patterns in the sources of sedimentary rocks in North America at a continental scale. Between 600 and 450 million years ago (Ma), ancient continental shield sources dominated. Around 450 Ma, detritus from the Caledonian-Appalachian mountains overwhelmed sediment from all older sources, and is documented over large areas of the southern, western, and northern margins of North America. This material continued to dominate the sediment supply until about 150 Ma, probably due to cannibalistic recycling of sedimentary rocks formed earlier. Around 150 Ma, the rising western Cordillera delivered new and different detritus to the sedimentary system.

Journal Article↗
PubMed2001

Genetic diversity of rhizobia nodulating Trifolium ambiguum in North America.

Kura clover (Trifolium ambiguum M.B.) is a persistent rhizomatous forage legume, whose use in the U.S.A. is limited by establishment difficulties in part attributable to nodulation problems. In this study, soil was collected from established stands of Kura clover growing in 9 diverse North American environments. Rhizobia were plant-trapped using Kura clover cv. Endura as host, then rhizobia from nodules fingerprinted using BOX-PCR. The diversity of isolates from North America was then contrasted to that of rhizobia from a single Caucasian environment (Russia), the center of origin for this species. Populations were characterized using clustering methods, and genetic diversity estimated using the Shannon-Weaver diversity index. The genetic diversity of the North American populations was extremely limited, all isolates being closely related to two of the strains found in a locally available commercial inoculant. In contrast, Russian isolates formed a distinct cluster with significant internal genetic diversity. Genetic diversity indices for the North American and Russian populations were 3.5 and 10.76, respectively. The implication of this and other studies is that Kura clover is highly specific in Rhizobium requirement. If the performance of this legume in the U.S.A. is to be improved, either by modifying current establishment practices or plant breeding, it is essential that these studies be paralleled by more collections and evaluation of rhizobia from its center of origin, given the extremely limited diversity of rhizobia found in North America.

Cluster Analysis↗
PubMed2003

CANCER resistance surveillance program: initial results from hematology-oncology centers in North America. Chemotherapy Alliance for Neutropenics and the Control of Emerging Resistance.

OBJECTIVE: The CANCER (Chemotherapy Alliance for Neutropenics and the Control of Emerging Resistance) surveillance program was initiated to collect culture data on antimicrobial and antifungal agents in hospitals treating neutropenic patients in North America, as a means to monitor the development of microbial resistance. METHODS: A total of 2042 isolates from bloodstream, respiratory, urinary, and cutaneous infections in 2000-2001 were submitted by 33 oncology centers, clinics, and hospitals in North America, sent to a central laboratory, and tested by National Committee for Clinical Laboratory Standards methods against 42 different antimicrobials. RESULTS: Staphylococcus aureus, Escherichia coli, coagulase-negative staphylococci, Enterococcus spp., and Klebsiella spp. represented the most frequently isolated pathogens during the initial benchmark year. The incidence of extended-spectrum beta-lactamase-producing phenotypes ranged from 1.6% to 4.6% among E. coli and Klebsiella spp. Amikacin, tobramycin, polymyxin B, and piperacillin/tazobactam provided the highest susceptibility rates against Pseudomonas aeruginosa isolates. Yeast bloodstream isolates demonstrated complete susceptibility to amphotericin B, but 14% of strains were considered to have high-level fluconazole resistance. CONCLUSIONS: Elevated resistance rates when compared to general hospital strains were not observed in the CANCER program during the baseline year of this novel longitudinal, resistance surveillance program. The prevalence of gram-positive pathogens, although representing more than 50% of all bacterial isolates, was slightly lower than that reported previously by other investigators. Continued evaluation for antimicrobial resistance as well as changes in the prevalence of gram-positive pathogens requires the use of longitudinal surveillance programs such as the CANCER program. Such initiatives allow the development of therapeutic strategies for coping with changes in resistance and pathogen prevalence in this dynamic at-risk patient environment.

Anti-Bacterial Agents↗
PubMed2000

Patterns of intraspecific diversification in the Piriqueta caroliniana complex in southeastern North America and the Bahamas.

We use chloroplast DNA (cpDNA) variation and nested clade phylogeographic analyses to infer the historical processes that have contributed to the high level of morphological and ecological diversification present in a group of herbaceous perennials (the Piriqueta caroliniana complex) in North America and the Bahamas. The presence of morphologically distinct and intercompatible varieties (morphotypes) that can be distinguished based on suites of taxonomic characters (e.g., leaf shape, pubescence type, stature) and contrasting habitat affinities (from marshes to dry pinelands and sand scrub) makes this group particularly appropriate for studies of intraspecific diversification. To examine the distribution of haplotypes among populations, we sampled 467 individuals from 55 locations in Florida, Georgia, and the northern Bahamas (Grand Bahama and Abaco) and screened each individual for cpDNA variation using restriction fragment length polymorphism (RFLP) and heteroduplex analyses. We develop a one-step haplotype phylogeny for this group and use the geographic distributions of haplotypes and clades to test specific phylogeographic hypotheses using the methods developed by Templeton and his colleagues (Templeton 1998). In general, the distribution of haplotypes was strongly influenced by limited dispersal distances, with the more recently derived haplotypes having much lower levels of dispersion and lower frequencies in populations than the ancestral haplotypes. The patterns of clade and haplotype dispersion and displacement and the distribution of morphotypes imply at least three cases of long-distance dispersal and one case of historical fragmentation. The historical patterns inferred for populations of Piriqueta are consistent with known biogeographical events, historical vegetation change, and the concordant patterns of multiple Pleistocene refugia that have been observed for a number of other taxa in southeastern North America.

Bahamas↗
PubMed1992

Pyomyositis in North America: case reports and review.

We report two cases and review the characteristics of pyomyositis. The courses of patients who presented with pyomyositis at the Maricopa Medical Center (Phoenix) are detailed. Ninety-eight reported cases over the last 20 years in North America, found through a MEDLINE search, are summarized. Infection with the human immunodeficiency virus (HIV) may predispose the patient to pyomyositis. The onset is usually insidious with progression to large purulent collections and significant morbidity. The diagnosis is frequently suggested by findings of imaging studies. Staphylococcus aureus is responsible for most cases in tropical areas but is less frequently associated with cases in North America. Since infection with HIV predisposes patients to bacterial infections, pyomyositis will occur more frequently in this patient population. Increased awareness of the disease will improve management. Following aspiration or surgical drainage, therapy with broad-spectrum empirical antibiotics may be considered initially in the treatment of pyomyositis.

AIDS-Related Opportunistic Infections↗
PubMed2002

Evidence for historical introgression along a contact zone between two species of char (Pisces: Salmonidae) in northwestern North America.

Phylogeographic analyses can yield valuable insights into the geographic and historical contexts of contact and hybridization between taxa. Two species of char (Salmonidae), Dolly Varden (Salvelinus malma) and bull trout (S. confluentus) have largely parapatric distributions in watersheds of northwestern North America. They are, however, sympatric in several localities and hybridization and some introgression occurs across a broad area of contact. We conducted a comparative phylogenetic analysis of Dolly Varden and bull trout to gain a historical perspective of hybridization between these species and to test for footprints of historical introgression. We resolved two major Dolly Varden mitochondrial DNA (mtDNA) clades (with 1.4-2.2% sequence divergence between haplotypes) that had different geographical distributions. Clade N is distributed across most of the range of Dolly Varden, from southern British Columbia through to the Kuril Islands in Asia. Clade S had a much more limited distribution, from Washington state, at the southern limit of the Dolly Varden range, to the middle of Vancouver Island. The distribution and inferred ages of the mtDNA clades suggested that Dolly Varden survived the Wisconsinan glaciation in a previously unsuspected refuge south of the ice sheet, and that Dolly Varden and bull trout were probably in continuous contact over most of the last 100,000 years. When bull trout were included in the phylogenetic analysis, however, the mtDNA of neither species was monophyletic: Clade S Dolly Varden clustered within the bull trout mtDNA clade. This pattern was discordant with two nuclear phylogenies produced (growth hormone 2 and rRNA internal transcribed sequence 1), in which Dolly Varden and bull trout were reciprocally monophyletic. This discordance between mtDNA- and nDNA-based phylogenies indicates that historical introgression of bull trout mtDNA into Dolly Varden occurred. Percent sequence divergence within these introgressed Dolly Varden (clade S) was 0.2-0.6%, implying that the introgression occurred prior to the most recent glaciation. Our analysis and other evidence of contact between divergent lineages in northwestern North America strongly suggests that the area may be the site of previously unsuspected suture zones of aquatic biotas.

Animals↗
PubMed1999

Transmission of Eurasian avian H2 influenza virus to shorebirds in North America.

Influenza A virus of the H2 subtype caused a serious pandemic in 1957 and may cause similar outbreaks in the future. To assess the evolution and the antigenic relationships of avian influenza H2 viruses, we sequenced the haemagglutinin (HA) genes of H2 isolates from shorebirds, ducks and poultry in North America and derived a phylogenetic tree to establish their interrelationships. This analysis confirmed the divergence of H2 HA into two geographical lineages, American and Eurasian. One group of viruses isolated from shorebirds in North America had HA belonging to the Eurasian lineage, indicating an interregional transmission of the H2 gene. Characterization of HA with a monoclonal antibody panel revealed that the antigenicity of the Delaware strains differed from the other avian strains analysed. The data emphasizes the importance of avian influenza surveillance.

Animals↗
PubMed1975

Intestinal anisakiasis. First case report from North America.

The first case of intestinal anisakiasis in North America is described. This parasitic disease is recognized as a public health hazard in Japan and Europe. Man becomes infected with a larval form of the nematode Anisakis by consuming raw or undercooked fish containing the parasite. Typically, patients present with acute abdominal syndromes. Clinical and reontgenographic features may cause confusion with regional enteritis. Histologically, a striking oesinophilic granulomatous reaction occurs. Anisakiasis is most effectively prevented by discouraging the consumption of raw fish.

Adult↗
PubMed1984

Diphtheria in North America.

The incidence of diphtheria has declined in North America during the last fifty years until it is now an uncommon disease. This general pattern is similar to that seen in other developed countries with well-organized immunization programmes, but certain noteworthy characteristics have been observed in recent years: foci of infection lingered in two population groups of low socio-economic status, in both of which the skin has been an important reservoir. In central areas of certain cities, endemic diphtheria, chiefly cutaneous, has occurred amongst indigent adult males living in unhygienic conditions; and in the native Indian population of Northern Canada diphtheria infection has been endemic in infants and children, many of the infections being of the skin or ear and toxic disease being uncommon. During the last few years, diphtheria outbreaks have not been reported in urban areas and possibly endemicity is now restricted to northern native populations. The number of infections detected in these northern endemic areas is steadily decreasing.

Adolescent↗
PubMed2000

Trichinella murrelli n. sp: etiological agent of sylvatic trichinellosis in temperate areas of North America.

Trichinella T5, collected from sylvatic carnivores in North America, was identified previously as a different phenotype of Trichinella, with an uncertain taxonomic level due to the availability of only 2 isolates. Cross-breeding experiments carried out with single female and male larvae of 2 strains of Trichinella T5, with single female and male larvae of 2 strains of Trichinella spiralis, Trichinella nativa, Trichinella britovi, Trichinella pseudospiralis, Trichinella nelsoni, and Trichinella T6, showed a reproductive isolation of Trichinella T5. Viable offspring were obtained only when a female of Trichinella T5 was crossed with a male of T. britovi, but not vice versa. Furthermore, the analysis of biological, biochemical, and molecular data of 32 isolates collected from sylvatic animals in the Nearctic region and identified as Trichinella T5 permitted its reassessment at the species level. Trichinella murrelli n. sp. is characterized by the following: distribution in temperate areas of the Nearctic region; newborn larvae production in vitro of 29-36/72 hr; nurse cell development time between 24 and 70 days postinfection; reproductive capacity index in Swiss mice 1.2-9.5, in wild mice 29.5-159.8, in rats 0.7-2.4, and in pigs 0.03-0.0004; no resistance to freezing; ribosomal DNA fragments of 7.2 kb and/or 11.4 kb, plus 2.2 kb and 1.8 kb present after Dra I digested DNA when probed with total T. spiralis RNA; a specific amplicon of 179 bp after polymerase chain reaction (PCR) amplification with the primer set SB147G; a specific fragment of 1,600 bp after PCR amplification with the primer set Ts43CA and Hhb I digestion; long incubation period; and moderate to severe pathogenicity for humans. The new species is most similar to T. britovi, though it differs from T. britovi in the pattern of 2 allozymes, in the patterns of major ribosomal DNA and PCR-restriction fragment length polymorphism fragments, and in geographical distribution.

Animals↗