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PubMed2006

Asymmetric male and female genetic histories among Native Americans from Eastern North America.

Previous studies have investigated the human population history of eastern North America by examining mitochondrial DNA (mtDNA) variation among Native Americans, but these studies could only reconstruct maternal population history. To evaluate similarities and differences in the maternal and paternal population histories of this region, we obtained DNA samples from 605 individuals, representing 16 indigenous populations. After amplifying the amelogenin locus to identify males, we genotyped 8 binary polymorphisms and 10 microsatellites in the male-specific region of the Y chromosome. This analysis identified 6 haplogroups and 175 haplotypes. We found that sociocultural factors have played a more important role than language or geography in shaping the patterns of Y chromosome variation in eastern North America. Comparisons with previous mtDNA studies of the same samples demonstrate that male and female demographic histories differ substantially in this region. Postmarital residence patterns have strongly influenced genetic structure, with patrilocal and matrilocal populations showing different patterns of male and female gene flow. European contact also had a significant but sex-specific impact due to a high level of male-mediated European admixture. Finally, this study addresses long-standing questions about the history of Iroquoian populations by suggesting that the ancestral Iroquoian population lived in southeastern North America.

Chromosomes, Human, Y↗
PubMed2003

Key pollen allergens in North America.

OBJECTIVE: To discuss major pollen aeroallergens in North America that are essential for effective immunotherapy and to propose a list of pollen aeroallergens that could be prioritized for allergen standardization. DATA SOURCES: PubMed was used to search the existing medical literature. No date restrictions were used. Keywords included allergy, aeroallergen, taxonomy, cross-reactivity, pollen, and specific genus and species names. RESULTS: Tree species possess relatively unique allergens, and representative members should be chosen at the genus or family level. In the Composite family, there is significant cross-reactivity between ragweed species within the Ambrosia genus. Selection of one species should be sufficient for skin testing and immunotherapy. Extensive allergenic cross-reactivity exists among grasses. Selection of timothy grass alone or in combination with a single northern grass species provides adequate coverage in the northeastern regions of North America. CONCLUSIONS: One of the goals within the field of allergy should be to identify high-priority targets for future development of standardized commercial extracts. The standardization of increasing numbers of allergen extracts potentially benefits the discipline of allergy by facilitating transfer of care among physician practices, improving uniformity of patient care, and providing a template on which geographically specific extract choices can be built.

Allergens↗
PubMed2005

Radiotherapy for invasive breast cancer in North America and Europe: results of a survey.

PURPOSE: To document and explain the current radiotherapeutic management of invasive breast cancer in North America and Europe. We also identified a number of areas of agreement, as well as controversy, toward which additional clinical research should be directed. METHODS AND MATERIALS: An original survey questionnaire was developed to assess radiation oncologists' self-reported management of breast cancer. The questionnaire was administered to physician members of the American Society for Therapeutic Radiology and Oncology and the European Society for Therapeutic Radiology and Oncology. We present the results of the comparative analysis of 702 responses from North America and 435 responses from Europe. RESULTS: Several areas of national and international controversy were identified, including the selection of appropriate candidates for postmastectomy radiation therapy (RT) and the appropriate management of the regional lymph nodes after mastectomy, as well as after lumpectomy. Only 40.7% and 36.1% of respondents would use postmastectomy RT in patients with 1-3 positive lymph nodes in North America and Europe, respectively. Sentinel lymph node biopsy was offered more frequently by North American than European respondents (p <0.0001) and more frequently by academic than nonacademic respondents in North America (p < 0.05). The average radiation fraction size was larger in Europe than in North America (p < 0.01). European respondents offered RT to the internal mammary chain more often than did the North American respondents (p < 0.001). North American respondents were more likely to offer RT to the supraclavicular fossa (p < 0.001) and axilla (p < 0.01). CONCLUSION: Marked differences were found in physician opinions regarding the management of breast cancer, with statistically significant international differences in patterns of care. This survey highlighted areas of controversy, providing support for international randomized trials to optimize the RT management of invasive breast cancer.

Breast Neoplasms↗
PubMed2005

Outcomes of planned home births with certified professional midwives: large prospective study in North America.

OBJECTIVE: To evaluate the safety of home births in North America involving direct entry midwives, in jurisdictions where the practice is not well integrated into the healthcare system. DESIGN: Prospective cohort study. SETTING: All home births involving certified professional midwives across the United States (98% of cohort) and Canada, 2000. PARTICIPANTS: All 5418 women expecting to deliver in 2000 supported by midwives with a common certification and who planned to deliver at home when labour began. MAIN OUTCOME MEASURES: Intrapartum and neonatal mortality, perinatal transfer to hospital care, medical intervention during labour, breast feeding, and maternal satisfaction. RESULTS: 655 (12.1%) women who intended to deliver at home when labour began were transferred to hospital. Medical intervention rates included epidural (4.7%), episiotomy (2.1%), forceps (1.0%), vacuum extraction (0.6%), and caesarean section (3.7%); these rates were substantially lower than for low risk US women having hospital births. The intrapartum and neonatal mortality among women considered at low risk at start of labour, excluding deaths concerning life threatening congenital anomalies, was 1.7 deaths per 1000 planned home births, similar to risks in other studies of low risk home and hospital births in North America. No mothers died. No discrepancies were found for perinatal outcomes independently validated. CONCLUSIONS: Planned home birth for low risk women in North America using certified professional midwives was associated with lower rates of medical intervention but similar intrapartum and neonatal mortality to that of low risk hospital births in the United States.

Breech Presentation↗
PubMed1999

Management of animal health emergencies in North America: prevention, preparedness, response and recovery.

Animal health emergency management (AHEM) is one of the most important issues confronting the world today and is the key to both food security (safety, quality, wholesomeness, affordability and abundance) and economic stability for many countries. Although the primary objective of emergency management in each of the countries of North America (Canada, Mexico and the United States of America [USA]) is implemented through individual AHEM systems, North America shares four common goals, as follows: preventing the introduction of foreign animal pathogens into North America being prepared to manage the outbreak of a foreign animal disease developing appropriate response strategies for control and eradication of disease taking active measures to recover from the animal health emergency in question. In the course of this paper, the authors provide an introduction to, and overview of, AHEM in North America. Furthermore, they outline the general infrastructure of prevention, preparedness, response and recovery strategies for Canada, Mexico and the USA. Finally, the authors discuss the future of AHEM in North America, concluding with a review of some of the joint activities currently being conducted with regard to AHEM.

Animal Diseases↗
PubMed1994

Status of bovine tuberculosis in North America.

The eradication of bovine tuberculosis from North America is in the advanced stages as Canada and the United States struggle to remove the last vestiges of the disease from the domestic livestock population. Canada realistically anticipates total eradication from the national cattle herd within the next few years. The United States must yet effectively deal with the increased tuberculosis exposure potential from imported steers and from bovine tuberculosis newly discovered in its captive cervid industry. This paper reviews the history and development of tuberculosis eradication programs in North America. The basic evolution is described from area testing to slaughter surveillance with follow-up epidemiological investigations as the program foundation. The current status of both countries is described and recognized deterrents to final eradication are discussed.

Abattoirs↗
PubMed1987

From Osler to Olafson. The evolution of veterinary pathology in North America.

Most branches of biological science in North America developed first in the United States, and later were taught and practiced in Canada. An exception was veterinary pathology, which as a discipline taught in veterinary colleges and as a field of research, developed first in Canada, and from there crossed the border to the United States. Pathology was first taught at the Montreal Veterinary College, founded in 1866 by Duncan McEachran, a graduate of the Edinburgh Veterinary College. From the outset, he formed a close association with the medical faculty of McGill University, permitting his students to attend the same classes in the basic subjects with the medical students. Eventually, the Montreal Veterinary College became formally affiliated with McGill University, as the Faculty of Comparative Medicine and Veterinary Science. The McGill veterinary faculty was forced to close for economic reasons in 1903, but it left an enduring legacy, particularly in the field of veterinary pathology. The legacy, a novel concept in the 1870's, was that pathology was the cornerstone of a veterinary education; the place where anatomy, physiology, chemistry and botany met with the clinical subjects, and gave the latter meaning. This tradition was formed at the Montreal Veterinary College by the world renowned physician William Osler, North America's leading medical teacher, whom McEachran had invited to teach at the College in 1876 in addition to his duties in the faculty of medicine. Osler had studied with Virchow in Berlin and applied his methods of autopsy technique and of scientific inquiry to his teaching of both human and veterinary pathology at McGill. Osler also undertook investigations into various diseases of domestic animals, at the request of McEachran, who doubled as Chief Veterinary Inspector for the Dominion Department of Agriculture. Osler left McGill University in 1884. Only after that year did other North American veterinary schools adopt pathology as a discipline of instruction. However, by 1884, Osler had already left his indelible imprint on the students (both medical and veterinary) he had taught in Montreal, one of whom took over the teaching of pathology in the veterinary college. Another, who followed Osler's example and also studied in Berlin with Virchow, wrote the first book in the English language on veterinary post mortem technique in 1889.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Diet, physical activity, and colorectal cancer among Chinese in North America and China.

In a population-based case-control study of colorectal cancer among Chinese men and women in western North America and the People's Republic of China, a common protocol was used to assess past life-style characteristics of 905 cases diagnosed during 1981-1986 and 2,488 controls. Risks for cancers of both the colon and rectum increased with increased food energy from fat, protein, carbohydrate, and all energy sources combined, for both sexes and on both continents. Yet, in multivariate analysis, colorectal cancer risk was significantly associated only with saturated fat; no relationships were seen with other dietary sources of energy. Colon cancer risk was elevated among men employed in sedentary occupations. On both continents and in both sexes, risks for cancers of both the colon and rectum increased with increasing time spent sitting. Further, the association between colorectal cancer risk and saturated fat was stronger among the sedentary than among the active. Risk among sedentary Chinese Americans of either sex increased more than fourfold from the lowest to the highest category of saturated fat intake. Among migrants to North America, risk increased with increasing years lived in North America. These observations suggest (a) that colorectal cancer risk increases with duration of exposure to a sedentary life-style and a diet rich in saturated fat; (b) that higher incidence among Chinese-American men relative to women is due to longer duration of these habits among men, who have lived longer in North America; and (c) that higher risk among Chinese Americans of both sexes relative to risk among the general population in China is due to differences in such habits. Attributable risk calculations suggest that, if these associations are causal, saturated fat intakes exceeding 10 g/day, particularly in combination with physical inactivity, could account for 60% of colorectal cancer incidence among Chinese-American men and 40% among Chinese-American women.

Adult↗
PubMed2002

Brief review of advances in the treatment of gastric carcinoma in North America and Europe, 1995-2001.

Gastric carcinoma is widespread in many South American and Asian countries but may be especially deadly in the West, due to a lack of programs for early diagnosis. Advanced gastric carcinoma is incurable, and the median survival time of patients with advanced disease is only 6 to 9 months. We sought to examine investigative trends in the utilization of new agents in the treatment of advanced gastric carcinoma in North America and Europe. Representative published reports of phase II and III clinical trials of therapies for gastric carcinoma by investigators based in North America and Europe from January 1995 through December 2001 were identified by a computerized search of the PubMed literature database. Fluorouracil, cisplatin, leucovorin, methotrexate, doxorubicin, and mitomycin were considered "conventional" agents; all other drugs were considered "new" agents. Of the 42 reports identified by the literature search, 17 were by investigators in North America and 25 were by investigators in Europe. All reports by investigators in North America were phase II trials, compared with 64% of those studies in Europe; the other studies by European investigators were phase III trials (36%). Chemotherapeutic drugs we considered "new" for the purpose of this study were investigated in 64% of all trials in North America and Europe. Eighty-one percent (22/27) of the 27 trials in which new agents were studied were phase II studies. We conclude that new agents are being widely incorporated in the investigation of advanced gastric cancer in North America and Europe. This trend is likely to be continued as more new chemotherapeutic agents are developed for clinical testing.

Antineoplastic Agents↗
PubMed1996

Special challenges of maintaining wild animals in captivity in North America.

The maintenance of wild animals in captivity in North America is regulated by a number of different laws and government agencies in each country. Member institutions of zoo and aquarium associations in Canada, the United States of America and Mexico experience an extra tier of regulation in the form of industry standards, which are sometimes stricter than those imposed by government. Climate, natural disasters and harmful pest species all contribute to the challenge of keeping animals in certain locales. Vigilance against zoonotic disease transmission is maintained through industry and government-mandated sanitation standards, which are fortified by reporting regulations of local, regional and Federal health agencies. Current controversies in the keeping of particular taxa in North America include the threat to non-human primate breeding programmes precipitated by strict new import regulations, the fear of herpesvirus B infection, and commercial airline transport bans. Successive human fatalities among elephant handlers have prompted the industry and governments to re-examine the manner in which these potentially dangerous creatures are maintained in captivity.

Animal Husbandry↗
PubMed1996

Comparison between Japan and North America in the post-hospital course after recovery from an acute coronary event.

We compared the post-hospital prognosis after an acute coronary event (acute myocardial infarction and unstable angina) in 106 patients in Japan vs. 789 patients in North America who were prospectively enrolled in the Multicenter Study of Myocardial Ischemia and were followed-up for an average of 26 months per patients. Risk factors more frequent in Japan were older age, males and smoking at enrollment, but the rest of many risk factors were similar. After adjusting for differences in clinical and medication variables, Cox analyses indicated patients in North America had a significantly greater risk of experiencing a primary end-point (cardiac death, non-fatal myocardial infarction or unstable angina) than patients in Japan (hazard ratio [North America:Japan] = 3.1, P = 0.003). There was a non-significant trend in the restricted end-points (cardiac death or non-fatal myocardial infarction) with North America having more frequent events than Japan (hazard ratio = 2.2, P = 0.12). The long-term outcome after recovery from an acute coronary event is more favorable in Japan than in North America, mostly due to a reduction in subsequent hospitalization for unstable angina. The reason for these findings cannot be explained by differences in the measured risk factors or medications.

Adult↗
PubMed1989

A survey of dentitions and removable partial dentures constructed for patients in North America.

The prevalence of removable partial dentures in North America is not known. This study was designed to collect information about (1) the indications for, (2) the teeth to be replaced with, and (3) the type of major connectors used in removable partial dentures. Five commercial dental laboratories situated in different regions of North America were selected to give as wide as possible a view of the production of removable partial dentures. Each laboratory was asked to provide details of 300 consecutive removable partial dentures. Photographs (35 mm) of master casts and processed partial dentures were obtained for more than 1300 patients. The color slides were analyzed and the remaining teeth and types of dentures were recorded. The dentures were classified as follows: cast frame denture, acrylic resin denture with or without some wrought metal, and acrylic resin denture with some cast units. The major connectors were classified as one of seven alternatives in the maxillae, and as one of six alternatives in the mandible.

Canada↗
PubMed2002

The transmissible spongiform encephalopathies: disease risks for North America.

Transmissible spongiform encephalopathies exotic to North America (BSE and associated diseases) are unlikely to be introduced or to persist should they be introduced into the United States [2]. Domestic TSEs (scrapie, CWD, and TME) seem to be relatively restricted in their host range, and none of these diseases is known to naturally cause disease in cattle. It is important that surveillance for TSEs continues, however, particularly in cattle because of the extreme consequences to the livestock industries, and potentially, public health, if BSE becomes established. Because the TSEs have implications beyond effects on their natural host species, adequate surveillance, control, and even eradication of these diseases should be goals for the livestock industries, wildlife managers, and animal health agencies in the United States.

Animal Diseases↗
PubMed1998

Antibodies to Ro/La, Cenp-B, and snRNPs antigens in autoimmune hepatitis of North America versus Asia: patterns of immunofluorescence, ELISA reactivities, and HLA association.

To assess whether demography is one of the important factors determining antibody response to nuclear antigens [ANA: SSA-Ro (52K and 60K), SSB-La, snRNPs (A, 70K, B'/B), and Cenp-B], we investigated 95 and 47 sera of autoimmune hepatitis (AIH) from North America and Asia, respectively, by immunofluorescent (IF) and recombinant ELISA. Correlations among nuclear IF patterns, ELISA, and disease indices were analyzed. The frequency and titer of individual antibodies differed significantly between the groups. Patients with speckled patterns were younger in both regions and had higher aspartate aminotransferase levels only in North America. HLA-A1, B8, DQ2, and DR4 or DR3 or both in North America, and A2, B61, DQ7, and DR4 in Asia were predominant. In Asia, B61 correlated with anti-70K, and DQ7 correlated with antibodies to 52K, Cenp-B, and B'/B. In North America, A1, B8, DR3 haplotype, and DQ2 correlated with antibodies to A and 70K. Anti-B'/B and DR4 in North America, and A2 in Asia, were associated with concurrent immunologic disorder. Individual ANA clusters correlated with individual HLA in the demography, and different HLA alleles might determine disease expression as well as different ANA being produced in AIH.

Adult↗
PubMed2004

Determination of the source areas contributing to regionally high warm season PM2.5 in eastern North America.

An ensemble-trajectory analysis technique known as Quantitative Transport Bias Analysis was applied to determine which geographic areas systematically contributed to above- and below-average fine particle mass (PM2.5) over eastern North America. Six-hour average measurements from 12 rural or suburban locations in eastern North America collected using a tapered element oscillating microbalance were individually associated with corresponding 3-day back-trajectories for the warm seasons (May-September) of 2000 and 2001. Much of the populated areas of northeastern North America were implicated in the build-up of PM2.5 to above-average concentrations. The finer structure of the Quantitative Transport Bias Analysis pattern indicated that transport from the Ohio River Valley, particularly the eastern portion of this area, was most often associated with the highest PM2.5 concentrations. In addition, air masses originating over a relatively large area from southeast Ohio to the western part of Virginia and the western Kentucky to central Tennessee area tended to result in relatively high PM2.5 concentrations over northeastern North America. These observation-based findings were consistent with the spatial distribution of the main sulfur dioxide emissions sources and the major oxides of nitrogen point sources.

Air Movements↗
PubMed2005

Invasion success of vertebrates in Europe and North America.

Species become invasive if they (i) are introduced to a new range, (ii) establish themselves, and (iii) spread. To address the global problems caused by invasive species, several studies investigated steps ii and iii of this invasion process. However, only one previous study looked at step i and examined the proportion of species that have been introduced beyond their native range. We extend this research by investigating all three steps for all freshwater fish, mammals, and birds native to Europe or North America. A higher proportion of European species entered North America than vice versa. However, the introduction rate from Europe to North America peaked in the late 19th century, whereas it is still rising in the other direction. There is no clear difference in invasion success between the two directions, so neither the imperialism dogma (that Eurasian species are exceptionally successful invaders) is supported, nor is the contradictory hypothesis that North America offers more biotic resistance to invaders than Europe because of its less disturbed and richer biota. Our results do not support the tens rule either: that approximately 10% of all introduced species establish themselves and that approximately 10% of established species spread. We find a success of approximately 50% at each step. In comparison, only approximately 5% of native vertebrates were introduced in either direction. These figures show that, once a vertebrate is introduced, it has a high potential to become invasive. Thus, it is crucial to minimize the number of species introductions to effectively control invasive vertebrates.

Animals↗
PubMed1990

Archaeoparasitology in North America.

The study of prehistoric parasitism through analysis of coprolites, mummies, skeletons, and latrine soils is rapidly growing. Its development in North America is interdisciplinary and is derived from the fields of physical anthropology, parasitology, and archaeology. The various parasite finds from North America are reviewed. The data show that prehistoric peoples in North America suffered from a variety of parasitic diseases. The validity of the findings are then considered. Although most finds of parasites from prehistoric contexts result from human infections, some finds cannot be verified as such. However, in combination with data from South America, it is clear that prehistoric peoples in the Americas were host to a variety of human parasites, some of which were not previously thought to be present before historic times.

History, Ancient↗
PubMedDate not supplied

The development of burn centers in North America.

Burn center development in North America began in the mid 1940s, surged in the 1970s, and had reached virtually every distinct medical market by 1985. The authors present chronologies of the establishment of 137 currently active burn centers in the United States and 27 burn facilities in Canada, discuss public policy and other influences on burn center development, and review burn admissions trends. Another 46 U.S. hospitals are identified as having shown interest in caring for serious burn injuries in recent decades. Since national admissions data first became available in 1970, the proportion of U.S. patients with burns treated in burn centers has increased from 10% to 40%. Data were obtained from a survey of 197 hospitals in the United States and Canada listed in recent Burn Care Resources directories of the American Burn Association and annual surveys of the American Burn Association and the National Center for Health Statistics. Further study of burn centers in both institutional and societal contexts and submittal of archival material are encouraged.

Burn Units↗