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Biomedical subjects

P Corey

Publications and source records attributed to P Corey.

At least 73 records · Page 4Linked to original sources
PubMed1978

A respiratory survey of cedar mill workers. II. Influence of work-related and host factors on the prevalence of symptoms and pulmonary function abnormalities.

The influence of certain work-related and host factors on the prevalence of respiratory symptoms and pulmonary function abnormalities in 405 red cedar workers and 187 control workers was examined. In cedar workers, but not in controls, the prevalence of chest symptoms increased with duration of exposure. The decline in pulmonary function with increasing duration of exposure was also more marked in cedar workers, but in both groups smoking was a more important determinant. Substantial proportions of cedar workers and, to a lesser extent, controls noted improvement of cough and wheeze, and particularly of conjunctivitis and rhinitis, when away from work. No deterioration, however, was found in pulmonary function during the work week in either exposure group. Atopic status was unrelated to the prevalence of chest symptoms or pulmonary function abnormalities; it was more common in workers with conjunctivitis and rhinitis, particularly in the cedar group. Similarly, Pi phenotype did not appear to influence the occurrence of either symptoms or lung function abnormalities.

Adult↗
PubMed1978

Development and standardization of a cytotoxic micro-assay for detection of enterotoxins: survey of enterotoxins from Escherichia coli of infant origin.

The development of a practical cytotoxic micro-assay for detection of enterotoxins in crude bacterial lysates of E. coli and other Gram-negative bacteria, is described. This quantitative assay is based on growth inhibition of mouse-fibroblasts, maintained in suspension or by inhibition of uptake of DNA precursors. Guidelines for performing the assay and evaluating the results by statistical considerations, are described. The choice of a relatively cheap medium and a suitable number of target cells to achieve cell doubling in 24 h is given. The concentrations of proteins in the crude lysates from strains of different origin, are not of equal potency; a predetermined but different protein concentration for strains from infants, adults or porcine origin, are recommended for detection of the toxins and for achieving reproducible results. Production of toxic proteins is enhanced by mitomycin C in toxigenic strains and not in non-toxigenic strains. Screening of a limited number of lysates from E. coli strains originating from infants and a comparison of the cytotoxicity of several known toxigenic and non-toxigenic strains from human adults and porcine origin, are presented.

Adult↗
PubMed1978

A respiratory survey of cedar mill workers. I. Prevalence of symptoms and pulmonary function abnormalities.

A respiratory-occupational questionnaire and spirometry were used to compare the prevalence of symptoms and pulmonary function abnormalities in 405 workers exposed to red cedar dust and 252 control workers exposed to other wood dusts. Compared with controls, the cedar workers were found to have a significantly higher prevalence of respiratory symptoms, cough, phlegm, wheeze and breathlessness, as well as more rhinitis and conjunctivitis. While, as expected, there was a clear relationship between respiratory symptoms and cigarette smoking, there was also evidence to suggest a synergistic effect between exposure to cedar dust and smoking. There was no difference in the lung function between cedar workers and controls. Sixty-five workers in the control group previously had worked in red cedar mills; they had a higher prevalence of respiratory symptoms than other workers in this group. Red cedar asthma was found in only 1.1% of the cedar workers. This condition usually develops in the early months of exposure, and workers who are affected tend to leave the industry. The probable incidence of red cedar asthma was estimated to be higher, around 4-5%.

Adult↗
PubMed1977

Dose-response relationships between amino acid intake and blood levels in newborn infants.

The objective of the present investigation was to investigate the nature of the blood amino acid response with amino acid intake in newborn infants. Forty-nine newborn infants of 640 to 4020 g birth weight and 26 to 40 weeks gestational age were placed on one of the following regimes within 48 hr of birth: intravenous dextrose with intravenous feeding of three levels of crystalline amino acid mixture, or of one level of casein hydrolysate, or with oral feeding of two levels of milk formula. Blood amino acid levels at 132 hr after feeding of graded levels of the intravenous amino acid solution were evaluated by regression analyses and compared to blood levels when casein hydrolysate was fed intravenously or milk formula was fed orally. At low levels of amino acid intake, such as were achieved with formula feeding, blood levels were relatively unchanged. However, with higher intakes, as were obtained with intravenous feedings, blood levels increased at rates which could be defined for each amino acid. This observation suggests that if the composition and rate of delivery of an amino acid solution is known, blood levels may be predicted.

Age Factors↗
PubMed1975

Winter illness and vitamin C: the effect of relatively low doses.

After their random -llocation to one of three treatment aroups, 622 volunteers received either vitamin C or placebo in a maintenance dose of 500 mg once weekly and a therapeutic dose of 1500 mg daily on the 1st day and 1000 mg on the next 4 days of any illness. Two forms of vitamin C were employed: a sustained-release capsule containing ascorbic acid and a regular tabet containing a mixture of sodium and calcium ascorbate. In the 448 subjects who completed an average of 15 weeks in the study of total of 635 episodes of illness were recroded. Respiratory symptoms were recorded on at least 1 day in 92 per cent of these episodes. There were no consistent or significant differences in the sickness experience of the subjects receiving the sustained-release vitamin capsules compared to those receiving the vitamin tablets, but subjects in both vitamin groups experienced less severe illness than subjects in the placebo group, with approximately 25 per cent fewer days spent indoors because of the illness (P smaller than 0.05). These results are compatible with the belief that supplementary vitamin C can reduce the burden of winter illness, but the intake need not be as high as has sometimes been claimed.

Adolescent↗
PubMedDate not supplied

Effects of ozone exposure: a comparison between oral and nasal breathing.

Mode of inhalation, by nose or by mouth, as a determinant of pulmonary toxicity to acute inhalant exposure has been investigated incompletely. This communication addresses whether there are significant differences in toxic pulmonary responses to acute ozone (O3) exposure between differing modes of inhalation (nasal vs. oral breathing). Changes in the results of pulmonary function tests and symptomatology of healthy young adults were compared following both exclusive nose and exclusive mouth breathing during a 30-min exposure to approximately 0.4 ppm O3 under conditions of moderate continuous exercise. In this single-blind, randomized, crossover study, no significant differences in either the results of pulmonary function tests or in symptomatology were found between the two modes of inhalation.

Adult↗
PubMedDate not supplied

Effects of particulate matter exposure and medication use on asthmatics.

The health risk associated with low-level air pollution exposure is still uncertain. The association between exposure and pulmonary function was assessed with personal sampling. Small, portable multipollutant samplers were used to assess personal exposure to particulate matter. Thirty-six asthmatic subjects participated in the study for up to 20 d in both summer (n = 10 d) and winter (n = 10 d); pulmonary function was assessed at the beginning and end of each sampling day, and medication use was recorded. A within-individual longitudinal analysis of the relationship between pulmonary function and particulate matter revealed an effect of season. In winter, pulmonary function increased as particulate exposure increased, which was explained by a confounding effect of medication use. Therefore, in addition to exposure, season of the year and medication use are factors that must be considered.

Air Pollutants↗
PubMedDate not supplied

Expectations of independence and life satisfaction among ageing spinal cord injured adults.

PURPOSE: The present study offers information about independence and life satisfaction over the lifespan for individuals with traumatic spinal cord injuries. METHODS: The study uses the health expectancy methodology to estimate expectations of the remaining years of life that may be spent in states of independence and satisfaction with life. SUBJECTS: The cohort studied had all incurred a spinal cord injury between the ages of 25 and 34, between the years 1945 and 1990 in central and south-eastern Ontario. RESULTS AND CONCLUSIONS: The study found that levels of independence and quality of life in the sample conformed closely to those found in other similar studies with the spinal cord injured population: 22% reported their own functional status as dependent, and 22% reported fair to poor life satisfaction. Expectations of independence appeared to decline steadily over the five decades studied, while expectations of modified independence increased proportionally. Estimates varied significantly for those with paraplegia vs. quadriplegia, and those with complete vs. incomplete lesions. Expectations of life satisfaction appeared to change after the 30 year mark; at that point, the balance changed so that expectations of dissatisfaction outweighed expectations of satisfaction. Multiple regression showed that independence was related to lesion level, completeness and recency of injury, and both independence and satisfaction were related to marriage and employment.

Activities of Daily Living↗
PubMedDate not supplied

A case-control study of the role of cold symptoms and other historical triggering factors in asthma exacerbations.

BACKGROUND: Asthma exacerbations can be provoked by many triggers such as allergens, respiratory irritants and viral infections. The relative importance of these has not been prospectively documented in a case-control study. OBJECTIVE: To assess the relative importance of colds and other nonclimatic historical triggers of asthma exacerbations. METHODS: One hundred and nineteen adults and children with asthma in two Canadian cities participated in a one-year study of the role of exacerbating factors in asthma. Among these, 36 pairs (21 adult, 15 children) completed the case-control study. Patients were considered cases if they developed an acute asthma exacerbation and notified the centre within 24 h to allow the completion of a questionnaire and viral studies (cultures of nasopharyngeal swabs and serology). Control people with asthma were matched for sex, age and area of residence, had no exacerbation during the preceding four weeks and participated within 48 h of the case patients. RESULTS: Case patients versus control patients had a mean age of 22 years versus 20 years, 50% versus 55% were male, and 92% versus 86% had at least one positive aeroallergen skin test. Cases were more likely to have taken regular inhaled steroids (63% versus 33%, P<0.002). Cases were more likely to report the following within the previous week: fever (P<0.001), sore throat (P<0.001), increase in nasal symptoms (P<0.01), increased dust exposure (P<0. 05), exposure to others with a cold (P<0.001) and, over the previous year, increased passive smoke exposure (P<0.05). Viral cultures and paired serology were negative. CONCLUSIONS: Symptomatic colds were the most common trigger of asthma exacerbations in the winter and spring, while a transient increase in dust exposure was also identified as a significant trigger. The association with chronic, passive smoke exposure and the use of inhaled costicosteroid medications likely reflected less stable pre-study asthma in those with exacerbations.

Adult↗
PubMedDate not supplied

The meaning of illness questionnaire: reliability and validity.

The reliability and validity of a recently developed Meaning of Illness Questionnaire (MIQ) is described. Questionnaire content was based on the work of Lazarus and Folkman (1984b). Three hundred twenty chronically ill subjects completed the 33-item MIQ and two open-ended questions. Subjects also completed the 45-item Psychosocial Adjustment to Illness--Self-Report Scale (PAIS-SR) described by Derogatis and Lopez (1983). Test-retest reliability for 70 subjects was, on the whole, substantial (kappa = .45 to 1.00) as was the ability of nurse clinicians to reliably categorize the qualitative component of the questionnaire into one of 12 categories (kappa = .64). The factor structure of the questionnaire supported the theoretical assumptions underlying the instrument. Three of the factors of meaning given the illness, R2 = .46, and/or three items, R2 = .60, had more power than coping behavior in explaining a person's adjustment to chronic illness. The questionnaire has accumulated reliability and validity in measuring a variety of concurrent yet divergent meanings that may be given an illness for three chronically ill populations--those with mixed cancer, rheumatological, and gastroenterological disorders.

Adaptation, Psychological↗