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Biomedical subjects

P N Corey

Publications and source records attributed to P N Corey.

At least 37 records · Page 2Linked to original sources
PubMed1987

A method for estimating "persons" versus "cases" from hospital morbidity data in the absence of unique personal identifiers.

The authors present a method for estimating the number of persons (as opposed to the number of admissions) admitted to hospital for a defined time period for specific diagnoses when unique personal identifiers are not available. A simple computer algorithm (algorithm 1), employing a family-based scrambled health insurance number in conjunction with diagnosis, sex, and age was used to estimate the rates of readmission to hospital specific diagnoses. A proportion of the hospital morbidity records used in the study did not contain a health insurance number; therefore, estimated readmission ratios for specific diagnoses, calculated from admissions with health insurance numbers, were applied to all admissions for those diagnoses to obtain the estimates of total persons admitted to hospital in the given time period. The validity of the methodology was tested for selected diagnoses for a specific year by 1) comparing estimates of persons obtained by applying algorithm 1 with manual counts of persons obtained through examination of printed lists of all Ontario admissions to hospital for the specific diagnoses, and 2) comparing actual counts of persons admitted to a specific hospital with computer estimates of persons admitted to that hospital. The conclusions drawn were that the method, using algorithm 1, is a valid one for obtaining estimates of the number of persons admitted to hospital in a given year with a specific diagnosis and that the information derived is potentially useful for conducting epidemiologic studies. Readmission ratios were also estimated through the use of a second algorithm (algorithm 2) which was not dependent on a scrambled health insurance number. Sensitivity and specificity of these ratios were found to be low when compared with ratios estimated by algorithm 1.

Algorithms↗
PubMed1985

Alcohol consumption and blood pressure: analysis of data from the Canada Health Survey.

Recent epidemiologic studies report a significant association between alcohol consumption and elevations in both systolic (SBP) and diastolic (DBP) blood pressures. To test this hypothesis, we conducted a multivariate analysis of physical examination and other data on 721 men and 697 women aged 20 or more collected during the Canada Health Survey in 1978-1979. SBP and DBP were considered as separate dependent variables in multiple regression models with the following independent variables: age, alcohol consumption (measured as a 7-day recall history and as an average frequency of consumption), serum cholesterol, plasma glucose, physical activity, Quetelet index, parental history of hypertension, cigarette consumption, income, education, and exogenous hormonal use in women. In both weighted and unweighted multiple regression analyses, we could not demonstrate for either sex, a significant association between alcohol consumption (as recorded and following quadratic and logarithmic transformations) and either SBP or DBP. For both sexes, only age and Quetelet index were highly significantly (P less than 0.0001) and consistently associated with both SBP and DBP. No other independent variables were consistently associated, for either sex, with SBP and DBP. Further, the dose-response patterns noted by other investigators suggesting either a positive and linear relationship or a curvilinear relationship were not found in either our univariate or multivariate analyses. Rather, the alcohol-blood pressure curves showed no consistent patterns of any kind in either sex. These findings do not support recent claims that alcohol consumption is a determinant of elevations in either SBP or DBP.

Adult↗
PubMed1985

Results of a controlled drug trial in membranoproliferative glomerulonephritis.

A prospective randomized drug trial was carried out on 59 patients with confirmed membranoproliferative glomerulonephritis (MPGN). The treatment group (27 patients) received cyclophosphamide, coumadin, and dipyridamole for 18 months, and the control group (32 patients) received no specific therapy. Complications of the renal disease such as hypertension and fluid retention were treated similarly in both groups. Entrance criteria included confirmed renal pathology demonstrating either types I or II MPGN, a corrected creatinine clearance (CCr) of less than 80 ml/min/1.73 m2, and/or proteinuria greater than 2 g/day. Actuarial survival was not different between the treatment and the control groups in either MPGN type and was 85% in type I and 90% in type II at 2 years. The change in renal function, as measured by both the slope of CCr and the plasma creatinine reciprocal (1/Cr) at 6, 12, and 18 months was not significantly different between treatment and control groups in either types I or II when tested by both parametric and nonparametric analysis. The age, sex, and initial level of CCr did not influence the rate of decline. Control and treatment group proteinuria was not different at any time point in either types I or II MPGN. The small numbers of type II MPGN cases do not give sufficient power to allow conclusions regarding this therapy in type II. We can conclude that this treatment is ineffective in altering the natural history of type I MPGN.

Adolescent↗
PubMed1984

Respiratory variables and exposure-effect relationships in isocyanate-exposed workers.

Respiratory variables in 95 isocyanate workers and 37 control workers were compared. The exposed workers had a slightly higher frequency of cough and shortness of breath than the controls and a significantly lower frequency of family history of asthma, hay fever, and bronchitis. The isocyanate workers had slightly lower baseline lung function than the control workers but demonstrated significantly larger declines in their pulmonary function over the work shift. Both groups showed some intraday and intraweek variation in lung function. The changes in lung function over the work shift varied with different job categories, the largest changes occurring in finishing-area workers. A gradation of response was observed when exposure was categorized as nil, low, or high, but no exposure-effect relationships could be demonstrated by regression analysis of either area or personal results.

Adult↗
PubMed1984

Effect of chest wall vibrations on pulmonary function in chronic bronchitis.

Manual chest wall vibration is one physiotherapeutic technique frequently employed in the management of respiratory disease. A clinical study was undertaken to examine the effects of manual chest wall vibrations on pulmonary function and arterial oxygen saturation in patients with chronic bronchitis. Twelve patients participated in a three-day experimental design where the factors of three different days and three different treatments were randomized and balanced. On one day, deep-breathing exercises were given; on another, deep-breathing exercises with vibrations; and on the remaining day, no treatment was given. Lung volumes were measured before and after each maneuver, and arterial oxygen saturation was monitored continuously. There was a significant decrease in the expiratory reserve volume (ERV) immediately following the deep-breathing exercises alone, which remained constant after the 15-minute rest period (p = 0.032). The remaining outcome parameters do not appear to be significantly affected. Chest wall vibrations do not decrease the ERV in patients with chronic bronchitis.

Aged↗
PubMed1983

Interaction of ozone and cigarette smoke exposure.

Possible interactions of ozone and cigarette smoke exposure have been tested in 2-hr chamber exposures of 26 male and 6 female subjects, all of whom were habitual smokers. Treatment conditions were air alone, air + cigarette smoking, ozone alone, and ozone + cigarette smoking. Ozone levels were increased progressively over four trials (0.37 ppm, 0.75 ppm, 0.50 ppm + intermittent exercise, and 0.75 ppm + intermittent exercise); exercise (50 W for 15 min alternating with 15-min rest) was intended to increase ventilation by a factor of 2.5. Ozone exposure reduced the carbon monoxide intake normally seen with smoking, as judged from smaller increments of blood carboxyhemoglobin readings. Ozone exposure alone gave rise to a decrease of lung function (forced vital capacity (VC), 1-sec forced expiratory volume, and maximum flow rates at 25 and 50% of VC), but the onset was slower and the response less dramatic than previously seen in nonsmokers, suggesting that the chronic effect of smoking may be to delay bronchial irritation by ozone. Smoking increased heart rate both at rest and during exercise, but this response was not materially influenced by simultaneous ozone exposure. It is concluded that over an acute 2-hr exposure, there is no appreciable interaction between cigarette smoking and responses to ozone.

Adult↗
PubMed1983

A comparison of three means of pressurized aerosol inhaler use.

The bronchodilator response to 200 micrograms of fenoterol hydrobromide using 3 different methods of inhalation from a pressurized aerosol metered-dose inhaler, was studied in 13 asthmatic patients. On 4 separate days and in random order, patients received either placebo aerosol or fenoterol aerosol delivered by the patients' own technique, delivered under supervision by a trained member of our staff, and delivered with a spacer device (Aerochamber) attached to the pressurized canister. There was no significant difference in the response to the 3 methods of active drug administration, but there was a significant difference (p less than 0.05) from the placebo control values. Thus, in this group of asthmatics the patients' own method of inhalation, using the standard dose of 200 micrograms of fenoterol from a pressurized aerosol metered-dose inhaler, appears to be as effective a means of bronchodilation as the other techniques used in this study.

Adult↗
PubMed1983

A systematic controlled study of pulmonary abnormalities in rheumatoid arthritis.

We have conducted a prospective comparison of 155 rheumatoid patients and 95 control subjects. Both groups were selected without regard to respiratory status, but were comparable in age, sex and smoking experience. The prevalence of respiratory symptoms, of past respiratory illnesses and of pulmonary function findings of airway obstruction was similar in both groups. However, the rheumatoids showed an increased frequency of chest crackles and abnormal chest radiographs, and had pulmonary function changes suggestive of a restrictive ventilatory defect. These pulmonary abnormalities were associated with smoking, the presence of nonpulmonary extraarticular features, the level of rheumatoid disease activity and treatment with oral corticosteroid or gold.

Adult↗
PubMed1980

Pi phenotypes in North American workers: racial differences and comparisons with reported frequencies.

The distribution of Pi phenotypes among Caucasian and Asian workers in British Columbia, Canada were found to differ significantly. Among Caucasians the frequency of the M allele was 0.9428, very similar to frequencies reported in other North American Caucasian populations. Among Asians only the M allele was found, further confirming the rarity of other alleles in such populations. The distribution of phenotypes in the Caucasian population agreed with the predictions of the Hardy-Weinberg law.

Adult↗
PubMed1980

Effect of layoff and rehire on respiratory variables of grain elevator workers.

A group of 77 grain elevator workers was examined at monthly intervals over a 7-month period. Approximately half of the workers were temporarily laid off for several months of this period, during which those who were steadily employed were involved in processing a reduced throughput of grain. The men who were laid showed a transient decrease in some respiratory symptoms during the months of layoff, followed by an increase after rehire. Those who were steadily employed showed a corresponding increase in these symptoms during the period of reduced grain movement, which did not change when the elevator returned to full activity. All of them demonstrated the greatest maximal expiratory flow rates during the midportion of the period of reduced work status, and the lowest values after either rehire or the restoration of full elevator activity. These longitudinal changes in respiratory variables are largely consistent with the effects of grain dust exposure, which may be at least partially reversible.

Absenteeism↗
PubMed1980

A controlled trial evaluating intensive plasma exchange in renal transplant recipients.

Sixty patients have been entered into a controlled trial evaluating the use of intensive plasma exchange (IPE) in renal transplant recipients. During the first three months post-transplant, patients receive either conventional anti-rejection therapy alone (control group) or conventional anti-rejection therapy and IPE (IPE group) for all rejection episodes. Twenty percent of the grafts in the control group versus 10% in the IPE group have been lost to rejection (p = NS). The actual three month patient and graft survival in the control group (97% and 70%), respectively, is similar to the IPE group (94% and 80%), as is the one year actuarial graft and patient survival in the two groups. No statistically significant benefit of IPE has yet been demonstrated but the trend is encouraging and the complication rate sufficiently low so as to justify continuing the study.

Clinical Trials as Topic↗
PubMed1979

Survey of the clinical use of pressurized aerosol inhalers.

Questions as to the use of pressurized aerosol inhalers were asked of 130 persons presenting for routine pulmonary function studies who had used such a device in the previous year. After spirometry was conducted the subjects used the inhaler; they were unaware that their technique of use was being observed. Only 10.8% performed correctly all 11 maneuvers suggested for the proper use of the inhalers, and 24.7% failed to perform more than 5 satisfactorily. There were significant differences in performance according to referral diagnosis (chronic obstructive lung disease v. asthma) and regularity of use of inhalers.

Adolescent↗
PubMed1979

Management of intractable ventricular tachyarrhythmias after myocardial infarction.

Twenty-five patients with recent or old myocardial infarction were studied because they had life-threatening ventricular arrhythmias that required repeated cardioversions and were intractable to medical management. All patients had had a large anterior infarction a mean of 4.6 weeks before the emergence of the arrhythmias and all had severe left ventricular dysfunction. Cardiac catheterization or autopsy revealed a left ventricular aneurysm in 18 of 18 patients and obstruction of the left anterior descending coronary artery in 20 of 20 patients. Of 16 patients treated surgically with aneurysm resection or coronary bypass grafting, or both, 10 (62 percent) were alive after 3 to 39 (mean 26) months of follow-up. The perioperative mortality rate was 31 percent and only one patient died during the postoperative follow-up period 4 months after discharge from the hospital. By contrast, all nine medically treated patients died either in the hospital (four patients) or suddenly within 2 months of discharge (five patients). Ventricular fibrillation was documented as the cause of death in five of these patients. Surgical intervention was found to improve significantly the survival of these patients (P less than 0.02). The perioperative mortality rate was lower when at least 4 weeks had elapsed from acute infarction to surgery (10 versus 67 percent) and when the procedure included coronary bypass grafting (13 versus 50 percent), although these differences were not statistically significant (P greater than 0.05).

Adult↗
PubMed1979

Racial differences in lung function: search for proportional relationships.

A comparison of lung function in Caucasian and East Indian woodworkers revealed marked differences in FEV, FVC, AND MMF in relation to predicted age- and height-specific values of these variables reported in the literature. These findings were not attributable to differences in smoking habits, frequency of respiratory disease, or employment characteristics. Rather, they suggested that the standard values employed were inappropriate for East Indians. An attempt was made to confirm previously reported suggestions of consistent proportional differences in lung function between racial groups which would permit the calculation of a single correction factor. Evidence of a consistent proportional relationship was found for FEV over a wide range of heights and for FVC over a limited range of heights. However, no such relationship was found for MMF.

Adolescent↗