PubMed Health⌕ Search

Biomedical subjects

P Orr

Publications and source records attributed to P Orr.

At least 19 recordsLinked to original sources
PubMed2006

Spectroscopic characterization of vacuum ultraviolet free electron laser pulses.

Because of the stochastic nature of self-amplified spontaneous emission (SASE), it is crucial to measure for single pulses the spectral characteristics of ultrashort pulses from the vacuum ultraviolet free electron laser (FLASH) at DESY, Germany. To meet this particular challenge, we have employed both photon and photoelectron spectroscopy. Each FEL pulse is composed of an intense and spectrally complex fundamental, centered at a photon energy of about 38.5 eV, with a bandwidth of 0.5% accompanied by higher harmonics, each carrying an intensity of typically 0.3 to 0.6% of that of the fundamental. The correlation between the harmonics and the fundamental is in remarkable agreement with a simple statistical model of SASE FEL radiation.

Journal Article↗
PubMed2005

Urticaria and large cell undifferentiated carcinoma of lung.

The association of urticaria with internal cancer is known mostly with lymphoreticular system malignancies. Rarely, it occurs with cancer of lung, mostly with adenocarcinoma or small cell carcinoma. We report a unique occurrence of urticaria on a patient who suffered from large cell undifferentiated carcinoma of lung. Only the treatment for malignancy relieved the patient from his long standing cutaneous manifestation.

Carcinoma, Large Cell↗
PubMed2001

Aboriginals with multiple sclerosis: HLA types and predominance of neuromyelitis optica.

BACKGROUND: MS is common in people of northern European ethnicity who live in northern geographic areas; however, MS is rarely identified among aboriginal peoples living in the same areas. OBJECTIVES: To determine the prevalence, clinical features, HLA type, and viral infections associated with MS among aboriginals in Manitoba, Canada. METHODS: A retrospective study was performed in which the clinical features of all aboriginal patients with MS together with HLA type and human herpesvirus-6, HIV-1, human T-cell lymphotropic virus-1, and endogenous retrovirus associated with MS (MSRV) infections were analyzed and compared with results from nonaboriginal patients with MS. RESULTS: Seven aboriginals with MS were identified with a period prevalence among aboriginals of 40:100,000. Clinical features included relapsing-remitting (n = 6) or primary progressive (n = 1) phenotypes with aggressive disease courses and frequent involvement of optic nerves and spinal cord (n = 5) compared with nonaboriginal patients. Autopsy of one patient showed necrosis and eosinophil infiltrates in a cervical spinal cord lesion and a demyelinated optic nerve. Analysis of HLA alleles at the DRB1 and DQB1 loci indicated that the HLA types detected were common in aboriginals, but there were no HLA alleles previously associated with the development of MS. Analysis of the copy number of MSRV did not show differences among aboriginals and nonaboriginals with or without MS. CONCLUSIONS: Aboriginals of Algonkian background are at increased risk for an aggressive type of MS, resembling neuromyelitis optica, which is resistant to conventional MS treatments and occurs independently of HLA alleles previously associated with MS.

Adult↗
PubMed2001

Rapid pharmacotherapeutic intervention for an influenza A outbreak in the Canadian Arctic: lessons from the Sanikiluaq experience.

In January of 2000 an outbreak of influenza-like illness (ILI) was identified by Health Centre nursing staff in the remote island Inuit community of Sanikiluaq, Nunavut. A staged approach to an intervention strategy was adopted and an intervention team dispatched within 48 hours with diagnostic, prophylactic, and therapeutic capabilities and the intent to evaluate the response as well. The presence of influenza virus was determined on site in 3 out of thirteen initial cases of ILI using portable kit based rapid detection. This permitted the use of zanamivir (an inhaled neuraminidase inhibitor) for prophylaxis in 201, and for treatment in 12 persons. Amantadine was only used in 16 and 52 were ineligible for medical intervention, mostly because they fell outside of the window of opportunity or for maternal/reproductive reasons. The intervention strategy framework adopted was felt to be successful and is presented for consideration in future intervention initiatives.

Adult↗
PubMed2001

Bronchiolitis in Inuit children from a Canadian central arctic community, 1995-1996.

During the winter and summer of 1996 two outbreaks of bronchiolitis occurred among Inuit children in the Canadian arctic community of Arviat. The epidemiology and clinical features of these epidemics were studied through a chart review of bronchiolitis cases occurring from September 1, 1995 to August 31, 1996. The attack rate over the year was 57% and the incidence was 1.25 cases per child-year at risk. The median age of cases was 9 months. Children developing bronchiolitis were more likely to be male (p = 0.006). Respiratory syncytial virus (RSV) was isolated from 17 cases occurring in January/February. The hospitalization rate during those two months was 38%, mortality was 3.3%, and demands upon local health care resources were high. Parainfluenza virus type 3 was isolated from 8 cases occurring during a second smaller outbreak in July/August. Hospitalized children were more likely to be bottle-fed (p = 0.01), and duration of hospitalization was greater for RSV positive versus negative children (p = 0.002). Among those hospitalized 22% required a second admission for the same illness. Identification of prevention strategies awaits an improved understanding of the role of agent, host and environmental factors in the pathophysiology of bronchiolitis in this population.

Arctic Regions↗
PubMed1999

Eye care utilization by older Americans: the SEE Project. Salisbury Eye Evaluation.

OBJECTIVE: To determine eye care utilization patterns among older Americans, particularly characterizing those who sought different types of providers, and the predictive factors for seeking eye care services in general and among those with diabetes and those with visual loss. DESIGN AND PARTICIPANTS: The SEE Project, a population-based survey of 2520 persons aged 65 to 84 in Salisbury, Maryland, provided cross-sectional data on eye care use. Questions on eye care use, demographics, medical history, and other factors were asked on the home interview. MAIN OUTCOME MEASURES: Use of an eye care provider in the previous year, with additional outcomes of use of different types of eye care providers. RESULTS: Blacks were significantly less likely to see any type of eye care provider over 1 year: 50% versus 69% among whites. Those who reported having a vision problem, those with more education, and those in the older age groups were significantly more likely to see either an ophthalmologist or an optometrist. Diabetes and driving a car were predictive factors for seeing an ophthalmologist but not for seeing an optometrist. Self-report of diabetes and eye care problems, and being a current driver, were predictive of seeing an eye care professional among those with visual impairment. CONCLUSIONS: Although blacks are known to be at greater risk for several age-related eye diseases, they are much less likely to see an eye care provider. Interventions that remove barriers to eye care services should be considered.

Aged↗
PubMed1999

Seroprevalence of Helicobacter pylori, incidence of gastric cancer, and peptic ulcer-associated hospitalizations in a Canadian Indian population.

The living conditions of many aboriginal communities in Canada may place their residents at risk for H. pylori infection. Our aims were to determine: (1) the seroprevalence of H. pylori in a traditional Indian community, (2) the clinical relevance of H. pylori infection in this population, and (3) if H. pylori could be identified by polymerase chain reaction from the local water. A demographic questionnaire was administered, and blood was collected from subjects in an Indian community in northwestern Manitoba. The serum was analyzed by ELISA for IgG to H. pylori and to CagA. ABO and Lewis antigens were tested. Age-adjusted incidence of gastric cancer and of hospitalizations associated with diagnoses of peptic ulcer were determined for the Indian and non-Indian Manitoba population in the years 1989-1993. Nested PCR was performed on lake water using H. pylori-specific primers and the amplicons probed with an internal Dig-labeled probe. Three hundred six (59%) of approximately 518 individuals who were resident in the community at the time of the study were enrolled. The ELISA for H. pylori was positive in 291 (95%). There was no association between H. pylori seropositivity and age, sex, gastrointestinal complaints, medications, housing characteristics, and ABO or Lewis antigen status. CagA was positive in 84.5% of infected subjects. The average annual age-adjusted incidence of hospitalizations associated with diagnoses of peptic ulcer disease in Manitoba was higher for treaty-status Indians (394.3/100,000) than for non-Indians (203.8/100,000), but gastric cancer rates were similar (11.2/100,000 vs 11.6/100,000). No H. pylori DNA was detected in the lake water. In conclusion, the seroprevalence of CagA-positive H. pylori is high in this representative Manitoban Indian community. This may be associated with an increased risk for peptic ulcer disease but is not associated with an increased risk for gastric cancer.

Adolescent↗
PubMed1999

Helicobacter pylori in the Canadian arctic: seroprevalence and detection in community water samples.

OBJECTIVE: Many North American arctic communities are characterized by risk markers associated with Helicobacter pylori (H. pylori) infection, including overcrowded housing and inadequate water supply and sanitation systems. Our aim was to determine the seroprevalence of H. pylori infection in two traditional Inuit communities in the central Canadian arctic and to test for the presence of H. pylori, by polymerase chain reaction (PCR), in local water supplies. METHODS: Samples of venous whole blood from adults and capillary blood from children were collected and analyzed by enzyme immunoassay and Helisal Rapid Test, respectively, for IgG antibody to H. pylori. Antibodies to CagA were detected by enzyme immunoassay, and ABO and Lewis antigens were also determined. Demographic and clinical information were collected by questionnaire. Water samples from each community were tested for H. pylori by PCR. RESULTS: One hundred-thirty (50.8%) of 256 subjects from the two communities were positive for H. pylori IgG antibodies. Seropositive subjects were more likely to be male, compared with seronegative individuals (p = 0.01). Antibody status did not differ with respect to age, community, alcohol or cigarette use, number of persons per household, gastrointestinal complaints or previous investigations, medications, or presence of blood group O, Lewis a-b+. CagA antibodies were detected in 78 (61.9%) of 126 H. pylori-seropositive subjects tested; however, 41 (35.3%) of 116 H. pylori-seronegative subjects were also CagA positive. Water samples taken from the water delivery truck in Chesterfield Inlet and two lakes near Repulse Bay were positive for H. pylori. CONCLUSION: The seroprevalence of H. pylori in the study group was higher than rates in southern Canadian populations, but lower than the seroprevalence previously documented in a Canadian subarctic Indian (First Nations) community. The detection of H. pylori in local water supplies may indicate a natural reservoir for the organism or possible contamination from human sewage.

ABO Blood-Group System↗
PubMed1998

Renal function in Inuit survivors of epidemic hemolytic-uremic syndrome.

We undertook a case-control study to evaluate the renal health of survivors of hemolytic-uremic syndrome (HUS) from the 1991 Arctic epidemic of Escherichia coli O157:H7 gastroenteritis 4 years after the epidemic. Eighteen children who developed HUS during the 1991 epidemic and 18 age- and sex-matched controls from the same community who had uncomplicated gastroenteritis were compared in 1995 for height, weight, blood pressure, urinalysis, and glomerular filtration rate (GFR), measured using continuous subcutaneous infusion of non-radioactive iothalamate. HUS survivors did not differ from controls in height, weight, systolic (HUS 118 mmHg, control 117 mmHg) or diastolic (HUS 64 mmHg, control 62 mmHg) blood pressures. Hematuria was detected more frequently in HUS survivors (11/18 vs. 4/18, P<0.05), but no child had proteinuria. Mean GFR did not differ between the two groups (HUS 159 ml/min per 1.73 m2, control 147 ml/min per 1.73 m2). Survivors of post-enteritic HUS from the 1991 Arctic E. coli 0157:H7 outbreak have excellent renal function 4 years after the epidemic.

Case-Control Studies↗
PubMed1998

The evolving epidemiology of chlamydial and gonococcal infections in response to control programs in Winnipeg, Canada.

OBJECTIVES: The purpose of this study was to describe and compare the transmission dynamics of chlamydia and gonorrhea in Winnipeg, Manitoba, Canada, and to assess implications for control programs. METHODS: Chlamydia and gonorrhea surveillance case reports (1988 through 1995) and contact-tracing reports (1991 through 1995) were examined. RESULTS: High incidence rates of both chlamydia and gonorrhea clustered in geographic core areas characterized by low socioeconomic status. A decline in the number of reported cases of chlamydia (61%) and gonorrhea (64%) occurred between 1988 and 1995. For chlamydia, the decline was most prominent in non-core area cases, while for gonorrhea it was similar in core and non-core areas. CONCLUSIONS: Chlamydia and gonorrhea appear to be evolving through different epidemic phases, with chlamydia transmission, in response to a newly introduced control program, becoming more core dependent and gonorrhea transmission becoming more sporadic in the face of a sustained control effort. Focused control programs, based on an understanding of the transmission dynamics of chlamydia and gonorrhea, may make their elimination a feasible goal.

Adolescent↗
PubMed1998

Follow-up of a decentralized colposcopy program for the investigation and management of cervical intraepithelial neoplasia in the central Canadian Arctic.

Cervical intraepithelial neoplasia (CIN) is the second leading cause of cancer in Canadian Inuit women, and the incidence ratio in this population is 3.1 times the Canadian average. In 1993 a program was developed in a regional northern health center (Churchill) to provide colposcopy and loop electrosurgery for women in the Keewatin District of the central Canadian Arctic. Data collected prospectively over the following 2.5 years are presented. One hundred and forty-six women were seen in 341 visits. Indication for referral included CIN I on Pap smear (54.1%), CIN II (34.9%), CIN III (9.6%), and carcinoma of the cervix (1.4%). Large loop excision of the transformation zone was performed at a rate of 9.7 procedures per 100 patient visits. Estimated travel cost-savings attributable to this northern program are $299,200 (Canadian). Use of portable colposcopy in patients' home communities is presently being considered in order to provide enhanced accessibility and further cost-effectiveness.

Arctic Regions↗
PubMed1997

Psychology impaired?

This article comments on M.J. Layman and J.R. McNamara's (1997) article about remediation for ethics violations. The author addresses the practice of regarding ethical violation, and its subset, boundary violation, and its subset, sexual misconduct, as synonymous. When professional impairment (disability) is seen as equivalent to sexual misconduct, the resulting generalized confusion impedes much needed progress in critical areas. The profession awaits structured assistance from the American Psychological Association to clarify and provide leadership in policy development.

Ethics, Professional↗
PubMed1995

Investigation and management of cervical intraepithelial neoplasia in Canadian Inuit: enhancing access to care.

Cervical intraepithelial neoplasia (CIN) is a major cause of morbidity among Circumpolar women. Cervical cancer comprised 15% of all cancers in Canadian Inuit women from 1969-1988. The age standardized incidence for invasive cervical cancer in Canadian Inuit women is 3.1 times the rate in the general Canadian population. Management of CIN in women of remote Arctic regions has traditionally required multiple visits to specialized medical centres for diagnosis, therapy and follow-up. Such centralized care requires separation of women from their families, resulting in significant medical, emotional and economic costs for the patient, her family and community. In the Canadian Central Arctic, a program for the diagnosis and therapy of CIN has been established using colposcopy with loop electrosurgery, performed by a trained local family practitioner and visiting gynecologist. Early program evaluation has indicated reduction in medical expenditures due to travel costs, minimal procedure-related morbidity and discomfort, and improved patient satisfaction associated with reduced separation from family and community. It is hoped that the program design, which harnesses technology in order to provide improved care closer to home, will be applicable to other Circumpolar regions.

Arctic Regions↗
PubMed1994

Epidemiology of infection due to Chlamydia trachomatis in Manitoba, Canada.

In a study of the epidemiology of Chlamydia trachomatis infection in Manitoba during 1981-1990, we retrospectively reviewed laboratory and clinical case notification records as well as hospital and health insurance data concerning pelvic inflammatory disease and ectopic pregnancy. After implementation of a control program in 1987, the annual incidence of chlamydial infection was highest among females aged 15-24 years (3,418 cases per 100,000 residents). Recurrent infection, which occurred in 13.4% of patients, was more common in women (P < .001), patients aged 15-24 years (P < .001), registered North American Indians (P < .001), and persons with concomitant gonorrhea (P < .001). Risk factors for dual (chlamydial and gonococcal) infection included male sex (P < .001) and young age (P < .001). Although the incidence of hospitalization and outpatient visits for pelvic inflammatory disease decreased (P < .001) from 1981 to 1990, the annual incidence of ectopic pregnancy increased from 10 to 16 cases per 1,000 reported pregnancies (P < .001). Control activities focusing on the primary prevention of C. trachomatis infection are presented. Strategies for improving secondary prevention (through case detection and treatment of lower genital infection) include the targeting of individuals with recurrent and multiple sexually transmitted diseases.

Adolescent↗