Biomedical subjects
S M Macdonald
Publications and source records attributed to S M Macdonald.
Actinic prurigo: clinical features and HLA associations in a Canadian Inuit population.
BACKGROUND: Actinic prurigo (AP) is an idiopathic familial photodermatitis. AP of the Inuit is rarely reported and poorly characterized. OBJECTIVE: Our purpose was to examine the clinical features and HLA associations of AP in an Inuit population. METHODS: Thirty-seven Inuit subjects with AP were administered a questionnaire and underwent a cutaneous examination. Other causes of photosensitivity were excluded. HLA class I typing was performed by polymerase chain reaction and sequence-specific primers and class II typing by polymerase chain reaction and sequence-specific oligonucleotide probes. RESULTS: Subjects were 81.1% female, 67.6% had a family history of photosensitivity, and all experienced seasonal variation. The average age at onset of photosensitivity was 29 years, and only 27% had a trend toward improvement in photosensitivity. Involvement of eyes and nonexposed skin was reported in 62.2% and 18.9% of subjects, respectively. Physical examination revealed involvement of the face (64.9%), lip (32.4%), ear (13.5%), and dorsal aspect of the hand (24.3%). HLA-DRB1*14 was present in 51.2% of subjects and 26.2% of controls (P =.022, odds ratio = 2.975). This is a previously unreported HLA association. CONCLUSION: AP in the Inuit is a seasonal, pruritic photodermatitis, often commencing in adulthood and worsening over time. A novel association with HLA-DRB1*14 has been discovered. Overall, this novel HLA association, the absence of HLA associations previously reported in non-Inuit populations, and clinical distinguishing features support the concept that AP in the Inuit may have a distinct immunopathogenic basis that translates into a different phenotype. It also raises the question of whether AP in the Inuit is a distinct photosensitivity disorder specific to this group that has been genetically isolated because of geographic and cultural seclusion.
The management of ear disease: guidelines for Aboriginal health care programs.
Middle ear disease represents a continuing burden of illness for children of circumpolar regions. Uncertainty in management has been shown to create a barrier to timely and adequate treatment. Consistent intervention strategies were sought for the management of middle ear disease in children of the central Canadian Arctic. The current literature was reviewed using MEDLINE. A consensus document was established in consultation with specialists in community medicine, infectious disease, otolaryngology, pediatrics, and community-based care providers. Definitive recommendations and supportive algorithms have been established for management of middle ear disease in Inuit children.
Obesity in Canada: a descriptive analysis. Canadian Heart Health Surveys Research Group.
OBJECTIVE: To describe the distribution of body fat, prevalence of obesity, and knowledge of cardiovascular disease in Canadian adults. DESIGN: Population-based, cross-sectional surveys. SETTING: Ten Canadian provinces between 1986 and 1992. PARTICIPANTS: A probability sample of 29,855 men and women aged 18 to 74 years was selected using health insurance registration files in each province. Anthropometry was performed on 19,841 (66%) of these adults. OUTCOME MEASURES: Body mass index (BMI); waist circumference; ratio of waist to hip circumference; knowledge of causes of heart disease. RESULTS: The overall prevalence of obesity (BMI > or = 27 kg/m2) increased with age and was greater in men (35%) than in women (27%). Abdominal obesity was also higher in men and increased with both age and BMI. Canadians with lower levels of education had a higher prevalence of obesity, which appeared at a young age. Canadians in Atlantic Canada mentioned lack of exercise, poor diet and smoking as causes of heart disease less frequently than those living in central or western Canada. CONCLUSIONS: Obesity continues to be common among Canadian adults. Policy and programs to promote healthy body weights must be intensified and directed at specific sociodemographic groups.
Regional and rural-urban differences in obesity in Canada. Canadian Heart Health Surveys Research Group.
OBJECTIVE: To describe regional and rural-urban differences in weight and weight loss patterns in Canadian adults. DESIGN: Population-based, cross-sectional surveys. SETTING: Nine Canadian provinces (excluding Nova Scotia) from 1986 to 1992. PARTICIPANTS: A probability sample of 27,120 men and women aged 18 to 74 years was selected using the health insurance registration files in each province. Anthropometry was performed on 18,043 participants (67%). OUTCOME MEASURES: Region of Canada (Atlantic, central, western); rural or urban residence (rural if participant resided in a community whose population was < 10,000, urban if population > or = 10,000); body mass index (BMI, kg/m2); percentage of participants trying to lose weight; reasons for trying to lose weight; level of leisure-time physical activity. RESULTS: Overall, mean BMI values in rural men (26.1 kg/m2) and women (25.3 kg/m2) were not significantly different from urban counterparts (25.7 kg/m2 and 24.8 kg/m2, respectively). Similarly, obesity (BMI > or = 27 kg/m2) was as prevalent in rural men (37%) and women (30%) as in urban participants (34% and 28%, respectively). However, a difference was observed in western Canada where 41% of rural and 34% of urban men were obese (odds ratio [OR], adjusted for age and education = 1.29; 95% confidence interval [CI] 1.06, 1.57), as were 35% of rural and 25% of urban women (OR, adjusted for age and education = 1.47; 95% CI 1.17, 1.84). Among men in western Canada, the rural-urban differences were greatest in the 25-64 year age group, whereas in women the differences were present at all ages. Overall, in Canada, urban men (26%) are more likely than rural men (23%) to be trying to lose weight; the reverse was true for women (39% and 42%, respectively). CONCLUSION: Considerable regional and rural-urban differences are seen in the patterns of weight and weight loss in Canada. A fuller understanding of the underlying behavioural determinants of these differences is needed. On the basis of such an understanding, effective programs to promote healthy weights for individuals and communities in these areas might be developed.
PCBs and organochlorine pesticide residues in otters (Lutra lutra) and in otter spraints from SW England and their likely impact on populations.
PCB and organochlorine pesticide residues were determined in otter (Lutra lutra) spraints (faeces) from nine catchment regions in SW England over the period 1989-1991. Results of analyses of tissues from 22 otters are also presented. Dieldrin occurred in the majority of spraint samples and p,p-DDE and total PCBs in all. Lindane occurred mainly in samples collected in spring. Lindane was not found in otter tissues collected after 1991, but dieldrin, p,p-DDE and PCBs were found in all tissues. Dieldrin and p,p-DDE concentrations were strongly correlated in otter tissues, but there were no correlations with lindane or PCBs. Mean concentrations of contaminants varied widely between catchments. It was considered that PCBs were the compounds of most concern in influencing otter populations and that levels in spraints from one catchment were likely to be sufficiently high to exert a negative effect on populations. While levels of PCBs were elevated above background level in several other catchments and some individual otters had high levels of PCBs, it was considered that they were not sufficient to significantly hinder further population consolidation of otters in SW England.
Impact of organochlorine pesticide residues and PCBs on otters (Lutra lutra): a study from western Britain.
A study of otter (Lutra lutra) populations and levels of organochlorine (OC) pesticide residues and PCBs in otter droppings (spraints) was made on eight stretches of river in three catchments in Wales and West Midland England. Population and contaminant levels were compared against target values. The otter populations (as measured by an index) remained stable on one stretch over 11 years, while they increased rapidly to equilibrium on four other stretches. The three lower stretches of rivers showed more erratic trends and on only one stretch did the index exceed, occasionally, the target value. Marking intensity at spraint sites was also lower at the three lowland sites. Concentrations of dieldrin, DDE and PCBs were significantly greater in spraint samples from the three lowland stretches. Over 50% of samples from the three lowland stretches had OC concentrations above the maximum allowable concentration, whereas most samples from the upland stretches had concentrations below the 'no effects level'. It is suggested that the colonization, by otters, of their former lowland range is inhibited by OC contamination of their food chain but, if contaminant levels can be reduced, spread will occur rapidly.
Impact of organochlorine pesticide residues and PCBs on otters (Lutra lutra) in eastern England.
A study of otter (Lutra lutra) populations and levels of organochlorine (OC) pesticide residues and PCBs in otter faeces (spraints) was made on rivers in East Anglia, England. Population and contaminant levels are compared against target values. It is thought that the native otter population was almost extirpated during the study period. The current population must derive largely, if not entirely, from captive-bred animals introduced since 1983. Its range has expanded little and population levels, measured as an index, were generally low. Concentrations of OC pesticides and PCBs were similar to those of lowland stretches of western rivers; however, samples had a smaller proportion of dieldrin and a greater proportion of PCBs. Overall 44% of samples had concentrations of contaminants exceeding the 'level of concern'. It is considered that contamination, especially by PCBs, remains a factor influencing otter populations, which may not be viable in East Anglia without repeated releases of captive-bred animals.
Objective evaluation of spiritual care: a case report.
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Physician recruitment by the J.A. Hildes Northern Medical Unit to northern Canada: 1970-1990.
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Pathological changes and organochlorine residues in tissues of wild otters (Lutra lutra).
In 1984 two adult, wild otters (Lutra lutra) from north Norfolk were subjected to full post mortem examinations. One was found dead and the other sick. Both were thin. No evidence of infectious disease was found, but there were organochlorine concentrations of 433 and 75 mg/kg of fat (69 per cent polychlorinated biphenyls in both) in skeletal muscle. Leiomyoma of the reproductive tract and adrenocortical hyperplasia in one otter were similar to age associated changes in other mammals. Integumentary, including pedal, lesions were present in both otters. The possibility that the pedal lesions were caused by the toxic effects of polychlorinated biphenyls is discussed.
Mercury, cadmium, and lead in British otters.
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Monoclonal antibody binding to congophilic elements in human Alzheimer brain.
Immunohistochemical studies, using a monoclonal antibody, SMP, raised in a mouse against aged human peripheral blood white cells, are described. This antibody reacts with dendritic reticulum cells in lymph node and tonsil, and, in Alzheimer brain, with argyrophilic plaques, neurofibrillary tangles, and cerebral vascular amyloid.
Immunological parameters in the aged and in Alzheimer's disease.
Peripheral blood from patients with Alzheimer's disease, elderly normal subjects and young (normal subjects) was examined with respect to leucocyte phenotypes and proliferative responses to lectins. Whole blood cell analysis showed that the neutrophil count was similar in all three groups. However, the lymphocyte count was depressed in the Alzheimer group. The monocyte count was reduced in the healthy aged and further reduced in the Alzheimer group. Analysis of peripheral blood mononuclear cells showed no change in the proportion of E+ cells, total T determined with the monoclonal antibody UCHT1 (similar to OKT3) and the T cell subsets: active E and T dot (discrete esterase staining). However, the proportion of T cells bearing the antigen detected by UCHT3 monoclonal antibody (similar to Leu 1 and OKT1) was reduced in the healthy aged and further reduced in the Alzheimer group. Proliferative responses to PHA, Con A, PA, and PWM were similarly depressed in both the aged and Alzheimer groups.
Manic depressive disease in childhood. A case report.
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