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PubMedDate not supplied

Common loon eggs as indicators of methylmercury availability in North America.

Increased anthropogenic mercury (Hg) deposition since pre-industrial times, and subsequent transformation of inorganic Hg to methylmercury (MeHg) in aquatic environments, has created areas in North America where Hg poses a relatively high risk to wildlife, especially long-lived, piscivorous species. From 1995 to 2001, we opportunistically collected 577 eggs abandoned by Common Loons from eight states. Egg-Hg concentrations ranged from 0.07 to 4.42 microg/g (ww) or 0.10 to 19.40 microg/g (dw). Mercury was higher in eastern than in western North America. Female blood-Hg concentrations strongly correlated with those of eggs from the same territory even though the mean intraclutch Hg difference was 25%. In New England, egg volume declined significantly as egg-Hg concentrations increased. Fertility was not related to egg-Hg concentrations. Based on existing literature and this study's findings, egg-Hg risk levels were established and applied to our US data set and an existing Canadian data set. Regionally, we found the greatest risk levels in northeastern North America. With few exceptions, loon eggs are suitable indicators of methylmercury availability on lakes with territorial pairs.

Animals↗
PubMed2005

Quantitative risk assessment of rabies entering Great Britain from North America via cats and dogs.

Great Britain has been rabies-free since 1922, which is often considered to be in part due to the strict laws requiring that imported cats and dogs be vaccinated and quarantined for 6 months immediately on entry into the country. Except for two isolated incidents, this quarantine policy has contributed to ensuring that Great Britain has remained free of rabies. In 2000, amendments to the UK quarantine laws were made and the Pet Travel Scheme (PETS) was launched for companion animals traveling from European Union countries and rabies-free islands. Since its introduction, it has been proposed that other countries including North America should be included within the UK scheme. A quantitative risk assessment was developed to assist in the policy decision to amend the long-standing quarantine laws for dogs and cats from North America. It was determined that the risk of rabies entry is very low and is dependent on the level of compliance (i.e., legally conforming to all of the required regulations) with PETS and the number of pets imported. Assuming 100% compliance with PETS and the current level of importation of cats and dogs from North America, the annual probability of importing rabies is lower for animals traveling via PETS (7.22 x 10(-6), 95th percentile) than quarantine (1.01 x 10(-5), 95th percentile). These results, and other scientific evidence, directly informed the decision to expand the PETS scheme to North America as of December 2002.

Animals↗
PubMed1991

Molecular evolution of eastern equine encephalomyelitis virus in North America.

We examined the rate and spatial pattern of eastern equine encephalomyelitis virus (EEEV) evolution in North America using primer-extension sequencing of viral RNA. Nucleotide sequences of the entire 26 S structural gene region of four EEEV strains revealed remarkable conservation between 1933 and 1985, with an estimated 0.7% divergence or 1.4 x 10(-4) nucleotide substitutions per site per year. Sequences from smaller 26 S regions of nine additional strains suggested that EEEV evolves in North America in a single lineage, with genetic exchange regularly occurring among enzootic transmission foci. In these limited 26 S genome regions, only synonymous nucleotide substitutions became fixed between 1933 and 1988, implying a high degree of conservation in protein structure. Short nucleotide sequences from a Panamanian, South American variety isolate revealed a relatively distant relationship to North American serotype viruses. This suggested genetic divergence between antigenic varieties, and independent evolution of EEEV in North and South America. Factors related to replication and epidemiology of EEEV, which may constrain its evolution in nature, are discussed. Possible mechanisms of genetic exchange among enzootic foci are also considered.

Amino Acid Sequence↗
PubMed2004

Allergy to cocamidopropyl betaine and amidoamine in North America.

BACKGROUND: The prevalence of allergy to cocamidopropyl betaine (CAPB) in North America has not been previously reported. OBJECTIVE: The aim of this study was to report on the most recent data on allergy to CAPB and a related allergen, amidoamine (AA). METHODS: Data was collected by the North American Contact Dermatitis Group from consecutive patients presenting for patch testing for diagnosis of presumed allergic contact dermatitis (ACD) from January 1, 2001, through December 31, 2001. RESULTS: Of 975 patients tested, 15 were patch-test positive to CAPB, 25 had positive reactions to AA, and 18 had positive reactions to both CAPB and AA. The most frequent site of dermatitis from CAPB was the head and neck region. CONCLUSION: In North America, both CAPB and AA are useful allergens for detecting ACD.

Allergens↗
PubMed2004

Epidemiology of constipation in North America: a systematic review.

OBJECTIVE: The aim of this study was to systematically review the published literature regarding prevalence, risk factors, incidence, natural history, and the effect on quality of life of constipation in North America. METHODS: A computer-assisted search of MEDLINE, EMBASE, and Current Contents databases was performed independently by two investigators. Study selection criteria included the following: (1) North American population-based sample of adults with constipation; (2) publication in full manuscript form in English; and (3) report on the prevalence, incidence, and natural history of constipation or impact of constipation on quality of life. Eligible articles were reviewed in a duplicate, independent manner. Data extracted were compiled in tables and presented in descriptive form. RESULTS: The estimates of the prevalence of constipation in North America ranged from 1.9% to 27.2%, with most estimates from 12% to 19%. Prevalence estimates by gender support a female-to-male ratio of 2.2:1. Constipation appears to increase with increasing age, particularly after age 65. No true population-based incidence studies or natural history studies were identified. In one cohort, 89% of patients with constipation still reported constipation at 14.7 months follow-up. From limited data, quality of life appears to be diminished by constipation, but the clinical significance of this is unclear. CONCLUSIONS: Constipation is very common, as approximately 63 million people in North America meet the Rome II criteria for constipation. Minimal data are available regarding incidence, natural history, and quality of life in patients with constipation. Effort should be expended toward the study of these topics, particularly in the elderly, who are disproportionately affected by this condition.

Constipation↗
PubMed2004

Molecular differentiation of Erwinia amylovora strains from North America and of two Asian pear pathogens by analyses of PFGE patterns and hrpN genes.

In order to determine a possible genomic divergence of Erwinia amylovora'fruit tree' and raspberry strains from North America, several isolates were differentiated by pulsed-field gel electrophoresis (PFGE) analysis, the size of short DNA sequence repeats (SSRs) and the nucleotide and deduced amino acid sequences of their hrpN genes. By PFGE analysis European strains are highly related, whereas strains from North America were diverse and were further distinguished by the SSR numbers from plasmid pEA29. The E. amylovora strains from Europe showed identical HrpN sequences in contrast to the American isolates from fruit trees and raspberry. Those were related to each other, but distinguishable by their HrpN patterns. The Asian pear pathogens differed in HrpN among each other and from E. amylovora. Erwinia pyrifoliae isolates and the Erwinia strains from Japan were ordered via their HrpN sequences in agreement with the PFGE patterns. For all three pathogens, dendrograms from PFGE and sequence data indicate an evolutionary diversity within the species in spite of a genetic conservation for parts of the hrpN genes suggesting a long persistence of the Asian pear pathogens in Korea and Japan as well as of fire blight in North America. Some of the divergent American E. amylovora isolates share PFGE patterns with the relatively uniform European strains.

Amino Acid Sequence↗
PubMed2004

The phylogeography of salmonid proliferative kidney disease in Europe and North America.

Salmonid proliferative kidney disease (PKD) is caused by the myxozoan Tetracapsuloides bryosalmonae. Given the serious and apparently growing impact of PKD on farmed and wild salmonids, we undertook a phylogeographic study to gain insights into the history of genealogical lineages of T. bryosalmonae in Europe and North America, and to determine if the global expansion of rainbow trout farming has spread the disease. Phylogenetic analyses of internal transcribed spacer 1 sequences revealed a clade composed of all North American sequences plus a subset of Italian and French sequences. High genetic diversity in North America and the absence of genotypes diagnostic of the North American clade in the rest of Europe imply that southern Europe was colonized by immigration from North America; however, sequence divergence suggests that this colonization substantially pre-dated fisheries activities. Furthermore, the lack of southern European lineages in the rest of Europe, despite widespread rainbow trout farming, indicates that T. bryosalmonae is not transported through fisheries activities. This result strikingly contrasts with the commonness of fisheries-related introductions of other pathogens and parasites and indicates that fishes may be dead-end hosts. Our results also demonstrate that European strains of T. bryosalmonae infect and induce PKD in rainbow trout introduced to Europe.

Animals↗
PubMedDate not supplied

Genetic diversity and distribution of Peromyscus-borne hantaviruses in North America.

The 1993 outbreak of hantavirus pulmonary syndrome (HPS) in the southwestern United States was associated with Sin Nombre virus, a rodent-borne hantavirus; The virus' primary reservoir is the deer mouse (Peromyscus maniculatus). Hantavirus-infected rodents were identified in various regions of North America. An extensive nucleotide sequence database of an 139 bp fragment amplified from virus M genomic segments was generated. Phylogenetic analysis confirmed that SNV-like hantaviruses are widely distributed in Peromyscus species rodents throughout North America. Classic SNV is the major cause of HPS in North America, but other Peromyscine-borne hantaviruses, e.g., New York and Monongahela viruses, are also associated with HPS cases. Although genetically diverse, SNV-like viruses have slowly coevolved with their rodent hosts. We show that the genetic relationships of hantaviruses in the Americas are complex, most likely as a result of the rapid radiation and speciation of New World sigmodontine rodents and occasional virus-host switching events.

Animals↗
PubMed2006

Contemporary causes of skin and soft tissue infections in North America, Latin America, and Europe: report from the SENTRY Antimicrobial Surveillance Program (1998-2004).

The morbidity and cost for cure associated with skin and soft tissue infections (SSTIs) have recently become more complicated because of the increasing prevalence of multidrug-resistant pathogens associated with this healthcare problem. The SENTRY Antimicrobial Surveillance Program has been monitoring SSTI since 1997, and now presents data from 3 continents over a 7-year period (1998-2004). Isolates were tested by reference broth microdilution methods at a central laboratory using the Clinical and Laboratory Standards Institute (formerly the National Committee for Clinical Laboratory Standards) methods and interpretative criteria. The predominant pathogens included Staphylococcus aureus (ranked 1st in all geographic regions), Pseudomonas aeruginosa, Escherichia coli, and Enterococcus spp. A considerable variation in the methicillin (oxacillin)-resistant S. aureus rate was noted between countries and continents, with the overall rate highest in North America (35.9%) compared with Latin America (29.4%) and Europe (22.8%). Vancomycin-resistant Enterococcus spp. increased in Europe (4.1%) and North America (6.2%) during the period, but remained low and relatively unchanged in Latin America. Among the P. aeruginosa isolates tested, susceptibility to imipenem was much lower in Latin America (65.3%) compared with the other regions (80.7-88.7%), and resistance being associated with an increase in metallo-beta-lactamase-producing strains in Latin America and in some European countries. Multidrug-resistant strains of P. aeruginosa were also more of a concern in Latin America (24.7%) compared with Europe (10.8%) or North America (3.2%). Latin America also had the highest occurrence of extended-spectrum beta-lactamase-producing isolates among E. coli (15.1%) and Klebsiella spp. (48.0%) when compared with other regions. Continued surveillance of pathogen prevalence and antimicrobial resistance patterns should provide information that is important to improve empiric care particularly in the hospital environment.

Anti-Bacterial Agents↗
PubMed1998

Molecular analysis of rubella virus epidemiology across three continents, North America, Europe, and Asia, 1961-1997.

E1 gene nucleotide sequences of 63 rubella virus isolates from North America, Europe, and Asia isolated between 1961 and 1997 were compared phylogenetically. Two genotypes were evident: Genotype I contained 60 viruses from North America, Europe, and Japan, and genotype II contained 3 viruses from China and India. The genotype I isolates prior to 1970 grouped into a single diffuse clade, indicating intercontinental circulation, while most post-1975 viruses segregated into geographic clades from each continent, indicating evolution in response to vaccination programs. The E1 amino acid sequences differed by no more than 3%; thus, no major antigenic variation was apparent. Among 4 viruses from congenital rubella syndrome that occurred following reinfection, only one amino acid substitution occurred in several important epitopes, indicating that antigenic drift is not important in this phenomenon. However, 2 viruses isolated from chronic arthritis exhibited changes in these epitopes. Isolates of the RA 27/3 vaccine strain were readily identifiable by nucleotide sequence.

Amino Acid Sequence↗
PubMed2026

Substance use and co-occurring mental health conditions among adolescents and young adults in North America: a systematic review.

BACKGROUND: Substance use and co-occurring mental health conditions are common among adolescents and young adults and represent an important clinical and public health concern in North America. Trauma exposure, psychiatric symptoms, and social adversity frequently co-occur with substance-related problems in this population. This systematic review aimed to synthesize evidence on prevalence patterns, associated clinical and psychosocial factors, and care-related implications described in the literature on adolescents and young adults with substance use and co-occurring mental health conditions. METHODS: This systematic review followed PRISMA guidelines and was preregistered in PROSPERO (CRD42024581685). A systematic search was conducted in MEDLINE (Ovid), Embase, PsycINFO, and Google Scholar. Eligible studies examined adolescents and young adults (≤ 25 years) in North America. A combination of subject headings, keywords, and synonyms for the concepts "adolescents," "young adults," "substance use disorders," and "co-occurring mental health conditions" was used. Of 1,882 records identified, 29 studies met the inclusion criteria. Given the heterogeneity of the literature, findings were synthesized narratively. RESULTS: The included studies showed heterogeneity in population, setting, denominator, and ascertainment method. Across the literature, depressive, anxiety-related, trauma-related, and externalizing mental health presentations were frequently reported alongside substance-related problems in adolescents and young adults. Trauma exposure, adverse childhood experiences, and broader social adversity were also commonly reported in association with substance-related problems across studies. Care-related implications were more limited and were largely derived as future directions mentioned across studies rather than direct evaluations of youth-specific service models. CONCLUSION: Co-occurring mental health and substance-related problems were frequently reported among adolescents and young adults in high-risk and service-engaged populations in North America. Trauma and social adversity were prominent across the reviewed literature, while direct evidence for evaluated, integrated, youth-specific care models remains limited. These findings support the relevance of developmentally appropriate, integrated, and trauma-informed approaches to care and highlight the need for further research directly evaluating improved service delivery models for this population. CLINICAL TRIAL NUMBER: Not applicable.

Humans↗
PubMed1998

Elevated lipoprotein(a) levels in South Asians in North America.

This report demonstrates that South Asians living in North America have elevated levels of Lp(a) compared with North American whites. Elevated Lp(a) levels may account, in part, for the tendency of South Asians to develop premature coronary heart disease (CHD).

Adult↗
PubMed1989

Autologous bone marrow transplants: different indications in Europe and North America. Advisory Committee of the International Autologous Bone Marrow Transplant Registry (ABMTR).

The International Autologous Bone Marrow Transplant Registry surveyed activity at 112 centres worldwide. Transplants increased from 265 in 1981 to over 1200 in 1987. Diseases most frequently treated by autotransplantation included non-Hodgkin lymphoma (22%), acute myelogenous leukaemia (19%), acute lymphoblastic leukaemia (15%), Hodgkin disease (15%), and neuroblastoma (5%). There were striking differences in the use of autotransplants between North America and Europe. Autotransplants for lymphomas and solid tumours comprised 94% of North American Autotransplants but only 41% of those in Europe. In contrast, leukaemia was the indication in 59% of Europeans but only 6% of North Americans. 65% of leukaemia autotransplants in Europe were done in first remission compared with 8% in North America. There were also differences in age and types of lymphoma autotransplanted--Burkitt and lymphoblastic lymphoma in young persons in Europe, versus large-cell lymphomas in older persons in North America.

Age Factors↗
PubMed2006

Infections by hepatitis B surface antigen gene mutants in Europe and North America.

Hepatitis B virus (HBV) mutants have usually been studied in patients in Asia because of the wider use of HBV immunization there and the resultant emergence of viral mutants. Nevertheless, HBV surface antigen (S) gene mutants also are found in Europe and North America. In Europe and North America, HBV with mutations in the portion of the S gene coding the "a" determinant of the hepatitis B surface antigen (HBsAg) have been documented in small numbers of infants born to HBV-infected mothers following post-natal HBV vaccine and hepatitis B immune globulin (HBIG) prophylaxis and in many liver transplant recipients who develop HBV re-infection despite HBIG prophylaxis. In some cases, these mutations have included a glycine to arginine substitution at position 145 (G145R), which results in a conformational change and different reactivity to monoclonal antibody reagents than that of the wild-type virus. Mutations in the a determinant (but not G145R) also have been reported in European patients with chronic HBV infection who have not received HBV vaccine or HBIG. However, it appears that such mutations are only responsible for a small proportion of "occult" or "silent" HBV infections, which are characterized by the presence of HBV DNA in serum in the absence of detectable HBsAg. However, some of these mutant forms of HBV in cases of occult HBV may theoretically escape detection and could present a risk to blood safety.

Amino Acid Substitution↗
PubMed2004

Evidence of avian pneumovirus spread beyond Minnesota among wild and domestic birds in central North America.

To detect avian pneumovirus (APV) in central North America, nasal turbinates or choanal deft tissues from domestic turkeys and wild birds were examined for the presence of APV RNA by reverse transcriptase-polymerase chain reaction (RT-PCR), whereas serum samples from domestic turkeys were analyzed for APV antibodies by enzyme-linked immunosorbent assay (ELISA). In 2002, the seroprevalence of disease in domestic turkeys in Minnesota remained high (42.3% of the flocks). In addition, there is evidence the disease has spread to turkey flocks in North Dakota (8.2%), South Dakota (7%), Iowa (10%), and Wisconsin (8.6%) as detected by RT-PCR and/or ELISA. House sparrows and ring-billed gulls sampled in Minnesota and snow geese from Saskatchewan, Canada, were found to harbor APV RNA. Sequence analysis of wild bird APV strains showed high amino acid sequence identity among wild bird isolates (<97%) and between wild bird and turkey viral isolates (93.2%-99.3%). This study demonstrated that APV infections were present in domestic turkey flocks and wild birds outside the state of Minnesota; however, the role of wild birds in spreading APV to domestic turkeys remains unclear.

Amino Acid Sequence↗
PubMed2004

Mitochondrial DNA and prehistoric settlements: native migrations on the western edge of North America.

We analyzed previously reported mtDNA haplogroup frequencies of 577 individuals and hypervariable segment 1 (HVS1) sequences of 265 individuals from Native American tribes in western North America to test hypotheses regarding the settlement of this region. These data were analyzed to determine whether Hokan and Penutian, two hypothesized ancient linguistic stocks, represent biological units as a result of shared ancestry within these respective groups. Although the pattern of mtDNA variation suggests regional continuity and although gene flow between populations has contributed much to the genetic landscape of western North America, some evidence supports the existence of both the Hokan and Penutian phyla. In addition, a comparison between coastal and inland populations along the west coast of North America suggests an ancient coastal migration to the New World. Similarly high levels of haplogroup A among coastal populations in the Northwest and along the California coast as well as shared HVS1 sequences indicate that early migrants to the New World settled along the coast with little gene flow into the interior valleys.

British Columbia↗
PubMed1997

Low prevalence of human papillomavirus infection in esophageal squamous cell carcinomas from North America: analysis by a highly sensitive and specific polymerase chain reaction-based approach.

Several studies have documented the frequent occurrence of human papillomavirus (HPV) DNA in esophageal squamous cell carcinomas (ESCC) in patients from geographic regions where the incidence of this type of cancer is high, such as parts of China. However, the prevalence of HPV infection in ESCC in patients from low incidence geographic regions, such as North America, remains controversial. Therefore, this study evaluates the prevalence of HPV in ESCC in patients from North America, a region where the population is considered at low risk for the development of this neoplasm. ESCCs in 51 patients from three North American cities were analyzed for the presence of HPV DNA by a highly sensitive and specific polymerase chain reaction (PCR) method. Tumor DNA was extracted from formalin-fixed, paraffin-embedded tissue specimens and assayed by PCR using an L1 HPV consensus sequence primer, as well as HPV 16 and HPV 18 E7 region primers. The use of consensus primers to the L1 region allows for detection of most known HPV types and many novel HPV types. Appropriately sized reaction products were analyzed by restriction fragment length polymorphism (RFLP) to confirm the presence and type of HPV, and to exclude products produced by amplification of human DNA sequences. After complete analysis, only one case (2%) of ESCC was HPV DNA positive. This case was independently confirmed using L1 and E7 consensus primers as HPV type 16 and was the only case that tested positive with either assay. These results show that, in contrast to geographic regions where ESCC is prevalent, HPV infection occurs infrequently in association with ESCC in patients from North America.

Adult↗
PubMed2006

Molecular evidence for an Asian origin and a unique westward migration of species in the genus Castanea via Europe to North America.

The genus Castanea (Fagaceae) is widely distributed in the deciduous forests of the Northern Hemisphere. The striking similarity between the floras of eastern Asia and those of eastern North America and the difference in chestnut blight resistance among species has been of interest to botanists for a century. To infer the biogeographical history of the genus, the phylogeny of Castanea was estimated using DNA sequence data from different regions of the chloroplast genome. Sequencing results support the genus Castanea as a monophyletic group with Castanea crenata as basal. The three Chinese species form a strongly supported sister clade to the North American and European clade. A unique westward expansion of extant Castanea species is hypothesized with Castanea originating in eastern Asia, an initial diversification within Asia during the Eocene followed by intercontinental dispersion and divergence between the Chinese and the European/North American species during the middle Eocene and a split between the European and the North American species in the late Eocene. The differentiation within North America and China might have occurred in early or late Miocene. The North America species are supported as a clade with C. pumila var. ozarkensis, the Ozark chinkapin, as the basal lineage, sister to the group comprising C. pumila var. pumila, the Allegheny chinkapin, and Castanea dentata, the American chestnut. Morphological evolution of one nut per bur in the genus may have occurred independently on two continents.

Base Sequence↗