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L MacLean

Publications and source records attributed to L MacLean.

At least 19 recordsLinked to original sources
PubMed2005

"Bounce at the Bell": a novel program of short bouts of exercise improves proximal femur bone mass in early pubertal children.

OBJECTIVES: To examine the effects of a simple and inexpensive physical activity intervention on change in bone mass and structure in school aged children. METHODS: Fifty one children (n = 23 boys and 28 girls; mean age 10.1 years) participated in "Bounce at the Bell" which consisted of 10 counter-movement jumps 3x per day (total approximately 3 min/day). Controls were 71 matched children who followed usual school practice. We assessed dietary calcium, physical activity, physical performance, and anthropometry in September and after 8 months of intervention (June). We measured bone mineral content (BMC) and bone area at the lumbar spine, total body, and proximal femur. Proximal femur scans were also analysed for bone geometry and structural strength using the hip structural analysis program. Lean and fat mass (g) were also calculated. RESULTS: Groups were similar at baseline and did not differ in weight, height, total body, lumbar spine, proximal femur, or femoral neck BMC. Control children had a greater increase in adjusted total body BMC (1.4%). Intervention children gained significantly more BMC at the total proximal femur (2%) and the intertrochanteric region (27%). Change in bone structural parameters did not differ between groups. CONCLUSIONS: This novel, easily implemented exercise program, took only a few minutes each day and enhanced bone mass at the weight bearing proximal femur in early pubertal children. A large, randomised study of boys and girls should be undertaken powered to test the effectiveness of Bounce at the Bell in children at different stages of maturity, and in boys and girls independently.

Analysis of Variance↗
PubMed2001

Nitric oxide and cytokine synthesis in human African trypanosomiasis.

Plasma and cerebrospinal fluid (CSF) concentrations of nitrate and the cytokines interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-10, and IL-4 were measured in 91 African trypanosomiasis patients before and after treatment. Nitrate levels overall were not significantly elevated over those for control persons, but a marginal increase in plasma nitrate was detected in patients reporting illness of <40 days' duration. Plasma IFN-gamma and total TNF-alpha concentrations increased during infection, but free TNF-alpha levels were low in all patients. The most dramatic cytokine response was for IL-10, which was significantly elevated in both plasma and CSF during infection but returned to control levels after treatment. The results indicate that human African trypanosomiasis leads to the development of a strong anti-inflammatory cytokine response.

Animals↗
PubMed1999

A model for building collective capacity in community-based programs: the Elderly in Need Project.

As the focus of health promotion moves from individuals to organizations, communities and broader social policy, the models that guide public health program planning and development need reexamination. Public health nurses are gaining experience in strengthening and supporting the ability of communities to grow and change. This study aimed to illuminate the process. Data, gathered as part of an action research project to develop individual and community-based strategies to decrease isolation in frail older adults, provided a rich source of qualitative data. Analysis was directed toward identifying the factors and processes of capacity-building. The emerging model was clarified and partially validated with academics and practitioners from health promotion programs across the age span. Four stages of building collective capacity were identified: identifying common ground, working cooperatively, working in partnership, and working across the community. At each stage, processes of relationship building, project management and capacity-building resulted in stage specific products. A model of building collective capacity, grounded in community health practice and supported by the literature provides a base for developing practice indicators, and practice guidelines which will strengthen the ability to reach health goals.

Aged↗
PubMed1996

Does Genetic Predisposition Influence Surgical Results of Operations for Obesity?

BACKGROUND: There is a familial predisposition to obesity. We wished to document the incidence of obesity (BMI > 40 kg m(2)) in the immediate relatives (parents and siblings) of obese patients who were candidates for gastric restrictive surgery. We determined if a familial predisposition to obesity would influence the surgical results. METHODS: The height, weight and BMI were obtained in 1841 relatives of obese patients and in 1059 relatives of normal weight controls. The results of gastric surgery after 52.9 +/- 23.1 months were obtained in 44 patients with a familial history of obesity and in 34 patients without a familial history. RESULTS: Patients presenting with a BMI > 40 kg m(2) were 24.541 times more likely to have a first degree relative with morbid or super obesity than individuals in the control group. Mothers were twice as likely to be severely obese as fathers. A successful result (BMI < 35 kg m(2) or less than 50% excess weight) occurred 52.9 +/- 23.1 months in 77% of patients with a family history of obesity.and in 73% of patients without a familial predisposition (p = 0.79). CONCLUSIONS: There is a strong familial predisposition to obesity but over one-half of the immediate family members of obese patients have a BMI < 30 kg m(2). Gastric restrictive surgery induces satiety and produces a successful outcome regardless of familial predisposition. Patients who undergo surgery have a remarkably stable weight over the year prior to operation, suggesting they are defending a markedly elevated BMI.

Journal Article↗
PubMed1992

Sulphydryl reactivity of the HLA-B27 epitope: accessibility of the free cysteine studied by flow cytometry.

HLA-B27 has an unpaired cysteine on or near its serologically defined spondylitis associated epitope, and it has been argued that its sulphydryl side chain may be chemically reactive. In a previous study it was shown that chemical treatment of HLA-B27 cells with the sulphydryl binding agent p-chloromercuriphenylsulphonic acid (pCMPSA) specifically reduced binding of antibodies to HLA-B27 by up to 80%, as measured in a cellular enzyme linked immunosorbent assay (CELISA). The effect of sulphydryl blockade on intact B27 cells was investigated using flow cytometry. Compared with the CELISA, inhibition required higher concentrations of pCMPSA, and the degree of inhibition produced by a greater than or equal to 30 microM solution of pCMPSA as measured by flow cytometry (median 28.9%) was significantly lower than that measured by CELISA (median 73.6%; p = 1.6 x 10(-6)). Analysis of unfixed, cell surface HLA-B27 by flow cytometry suggests that on most B27 molecules the unpaired sulphydryl site is not available. On the basis of this evidence for modification after translation, a new 'altered self' hypothesis is proposed for the part which HLA-B27 plays in inflammatory disease.

4-Chloromercuribenzenesulfonate↗
PubMed1988

Respiratory health in chrysotile asbestos miners in British Columbia: a longitudinal study.

A respiratory survey was undertaken in chrysotile asbestos miners in British Columbia consisting of a questionnaire, spirometry, chest radiography, and physical examination. The tests were performed in 1977 and again in 1983. The population groups studied included 63 "exposed" (working in the plant more than nine years), 52 "controls" (working in the plant less than five years), and 38 residents of the village at the minesite. A subset of 39 was identified with high exposure (worked in the mill more than five years). Measured levels of environmental particulates were similar over the entire period of operation of the plant (1.4 to 14.0 million particles per cubic foot and 0.7-88.0 fibres/cc in the mill; 0.2 to 2.7 mpcf and 0.6 to 9.3 f/cc in the mine). The exposed groups were more likely to report cough and breathlessness than the two other groups and were also more likely to have abnormal FVC and chest x ray films (the latter not significant, p greater than 0.05) and to be more likely to have a combination of these abnormalities. There was no trend to progression in the combination of abnormalities associated with exposure on follow up. The heavily exposed group showed a significantly worse trend in FVC. This adverse trend was confined to those with initial abnormalities. Tobacco smoking did not increase the trend to progression in this group.

Adult↗
PubMed1987

Follow-up study of 232 patients with occupational asthma caused by western red cedar (Thuja plicata).

A total of 232 patients with red cedar asthma diagnosed by inhalation provocation tests were observed an average of 4 years after the initial diagnosis. The status during the follow-up examination was as follows: 96 patients continued to work with red cedar, and 136 left the industry and had no further exposure to red cedar in their jobs or hobbies. Of the 136 patients who left the industry, only 55 (40.4%) recovered completely, whereas the remaining 81 (59.6%) continued to experience attacks of asthma of varying severity. The initial pulmonary function tests were significantly higher among the asymptomatic group compared to the symptomatic group (FEV1 99.3 +/- 2.7% versus 90.5 +/- 2.2% predicted, respectively). Methacholine PC20 during the initial examination was higher among the asymptomatic group than in the symptomatic group (1.46 +/- 3.96 mg/ml versus 0.77 +/- 4.52 mg/ml, respectively). These findings indicate that the patients in the asymptomatic group were diagnosed at an earlier stage of the disease. This observation was confirmed by the significantly shorter duration of symptoms before diagnosis among the asymptomatic patients compared to the symptomatic patients (1.6 +/- 1.9 versus 2.6 +/- 4.3 years). Race, smoking status, immediate skin reactivity, and presence of plicatic acid-specific IgE antibodies did not influence the outcome of these patients. Of the 96 patients who continued to work with red cedar, 47 were exposed daily, whereas 41 were exposed intermittently.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Adaptive decisions in the use of hospital beds.

This article investigates the manner by which a physician adapts his decision on referral to hospital and length of hospital stay to variations in the pressure (access) to hospital beds. An index of adaptation is developed which measures the adaptation to pressure from standard bed-use statistics. An example of the index is given for psychiatric bed use in Canada.

Bed Occupancy↗
PubMed1986

The structure of the antigenic lipopolysaccharide O-chains produced by Salmonella urbana and Salmonella godesberg.

The lipopolysaccharides of Salmonella urbana and Salmonella godesberg, which belong in group N (O:30) of the Kauffmann-White system, were shown by SDS-PAGE electrophoresis, glycose analysis, periodate oxidation, methylation, and 1H- and 13C-n.m.r. analyses to have identical O-chains composed of repeating, branched pentasaccharide units having the structure: [----4)-beta-D-Glcp-(1----3)-alpha-D-GalNAcp-(1----2)-alpha-D-P erNAcp-(1----3)-alpha-L-Fucp-(1----]n 4 increases 1 beta-D-Glcp. The serological cross-reactivity of S. urbana and S. godesberg with Brucella abortus and Yersinia enterocolitica (O:9) can now be related to the presence of a 1,2-glycosylated N-acyl derivative of 4-amino-4,6-dideoxy-alpha-D-mannopyranosyl residues in their respective lipopolysaccharide O-chains.

Carbohydrate Conformation↗
PubMed1986

Structure of the O-chain polysaccharide of the phenol-phase soluble lipopolysaccharide of Escherichia coli 0:157:H7.

The phenol-phase soluble lipopolysaccharide isolated from Escherichia coli 0:157 by the hot phenol-water extraction procedure was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, periodate oxidation, methylation, and 13C and 1H nuclear magnetic resonance studies to be an unbranched linear polysaccharide with a tetrasaccharide repeating unit having the structure: (formula; see text) The serological cross-reactivity of E. coli 0:157 with Brucella abortus, Yersinia enterocolitica (serotype 0:9), group N Salmonella, and some other E. coli species can be related immunochemically to the presence of 1,2-glycosylated N-acylated 4-amino-4, 6-dideoxy-alpha-D-mannopyranosyl residues in the O-chains of their respective lipopolysaccharides.

Carbohydrate Conformation↗
PubMed1985

Respiratory abnormalities among workers in an iron and steel foundry.

A study of the health of 78 workers in an iron and steel foundry in Vancouver, British Columbia, was carried out and the results compared with those found in 372 railway repair yard workers who were not significantly exposed to air contaminants at work. The foundry workers were exposed to PepSet, which consists of diphenyl methane diisocyanate (MDI) and phenol formaldehyde and their decomposition products as well as to silica containing particulates. A questionnaire was administered by trained interviewers, and chest radiography, allergy skin tests, pulmonary function tests, and methacholine inhalation tests were carried out as well as measurement levels of dust and MDI. Compared with the controls, the foundry workers had more respiratory symptoms and a significantly lower mean FEV1 and FEF25-75% after adjustments had been made for differences in age, height, and smoking habit. Three workers (4.8%) had radiographic evidence of pneumoconiosis and 12 (18.2%) had asthma defined as presence of bronchial hyperreactivity, cough, and additional respiratory symptoms such as wheeze, chest tightness, or breathlessness. Sensitisation to MDI is probably the cause of asthma in these workers.

Adult↗
PubMed1984

Symptoms, pulmonary function, and bronchial hyperreactivity in western red cedar workers compared with those in office workers.

An epidemiologic health study was carried out on 652 cedar mill workers and a control group of 440 male office workers not exposed to air contaminants. Participants completed a medical-occupational questionnaire with trained interviewers, had allergy skin tests, performed spirometry, and had bronchial reactivity assessed by methacholine inhalation testing. After adjusting for differences in age, race, and smoking, cedar workers were found to have significantly higher prevalences of cough, phlegm, and dyspnea than did office workers. Symptoms of asthma and work-related asthma, but not persistent wheeze or doctor-diagnosed asthma, were reported in a significantly higher proportion of cedar workers than of office workers. Cedar workers also had significantly lower lung function test results than did office workers after controlling for height, age, race, and smoking. Bronchial hyperreactivity, defined by a methacholine PC20 less than 8 mg/ml, was more prevalent among cedar workers than among office workers, with the increase being limited to the nonatopic subgroup of workers. The prevalence of bronchial hyperreactivity increased with duration of employment among cedar workers but not among office workers. We conclude that exposure to western red cedar dust is harmful to the respiratory health of the workers, causing asthma and other respiratory symptoms, bronchial hyperreactivity, and lower levels of lung function.

Adult↗
PubMed1984

Host factors affecting longitudinal decline in lung spirometry among grain elevator workers.

The host factors affecting the longitudinal decline in lung function among 267 white male grain elevator workers who were still working in the industry and did not change their smoking habits over a period of six years were studied. Spirometric measures declined more rapidly in older grain handlers as compared with younger workers. Smokers had slightly greater decline in spirometry compared to nonsmokers, but the differences failed to reach the level of statistical significance. Acute changes in lung function over the course of one work week during the initial study were also positively correlated with subsequent decline in lung function, as was bronchial hyperreactivity determined during the follow-up study. Positive immediate skin reactivity to common allergens, presence and absence of respiratory symptoms, and initial lung function did not appear to influence the subsequent decline in lung function in this group.

Adult↗
PubMed1983

Epidemiologic health study of workers in an aluminum smelter in British Columbia. Effects on the respiratory system.

A health survey was carried out on all white males in an aluminum smelter in British Columbia. The survey consisted of a medical-occupational questionnaire, spirometry, chest radiography, and environmental monitoring. We have compared the results of a respiratory survey in 713 workers in the office and casting department with no significant exposure to air contaminants (control workers) with those of 797 potroom workers: 495 who spent more than 50% of their working time in the potroom (high exposure) and 302 workers who spent less than 50% of their working time in the potroom (medium exposure). Potroom workers (high) had a significantly greater prevalence of cough and wheeze than did those in the control group, and they had significantly lower mean forced expiratory volume in one second and maximal midexpiratory flow rate than did those in the control group after adjustment had been made for differences in age, height, and smoking habits. Potroom workers (medium) had a slightly greater prevalence of respiratory symptoms and lower lung function than did workers in the control group, but the differences were not significant. We were unable to demonstrate potroom asthma. The levels of total fluoride, gaseous fluoride, particulate fluoride, sulphur dioxide, and total particulates found in the potroom at the time of the study were below the currently accepted threshold limit values, but the levels of benzo-alpha-pyrene were high.

Adult↗