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Biomedical subjects

C D Bernholz

Publications and source records attributed to C D Bernholz.

9 recordsLinked to original sources
PubMed1989

Silica exposure and silicosis among Ontario hardrock miners: I. Methodology.

An epidemiological investigation was undertaken to determine the relationship between silicosis in hardrock miners in Ontario and cumulative exposure to silica (crystalline silica--alpha quartz) dust. This first report describes the cohort, the method of classifying the radiographs, and the identification of a case of silicosis.

Cohort Studies↗
PubMed1989

Silica exposure and silicosis among Ontario hardrock miners: II. Exposure estimates.

An epidemiological investigation was carried out to determine the relationship between silicosis in hardrock miners in Ontario and cumulative exposure to silica (free crystalline silica--alpha quartz) dust. This second report describes a side-by-side air-sampling program used to derive a konimeter/gravimetric silica conversion curve. A total of 2,360 filter samples and 90,000 konimeter samples were taken over 2 years in two mines representing the ore types gold and uranium, both in existing conditions as well as in an experimental stope in which dry drilling was used to simulate the high dust conditions of the past. The method of calculating cumulative respirable silica exposure indices for each miner is reported.

Environmental Exposure↗
PubMed1982

Dark adaptation with interposed white adapting fields.

It is proposed that dark adaptation following a moderate pigment bleach may nearly as well be carried out (and more conveniently) under low room lighting conditions as in complete darkness. To test this idea, dark adaptation curves were determined either immediately after the termination of a 3 min, 4.1 log td white pre-exposure field, or following 10 or 15 min of additional exposure to one of three low-level photopic (2.9, 2.4, 1.8 log td) backgrounds of white light. Dark thresholds measured after the additional exposure fell rapidly and reached the rod plateau of the normal dark adaptation curve with a maximal delay of 1.5 min (for the 10 min backgrounds) or 6.5 min (for the 15 min backgrounds). For the time to be spent in the dark, this meant a savings of 8.5 min. At smaller delays savings were even greater. The difference between savings and delay indicates whether or not an interposed background is feasible.

Dark Adaptation↗
PubMed1982

Process versus outcome in hypertension: a positive result.

We studied the association between the outcome of antihypertensive care and three items of that care among 230 hypertensive steelworkers who were referred to 83 physicians. The first item was the decision to treat some patients but not others: 63% of the patients were prescribed antihypertensive drugs and the mean decrease in their diastolic blood pressure (DBP) was greater than that among untreated patients (12.2 +/- 0.84 vs 7.8 +/- 0.83 mm Hg [+/- SEM], p less than 0.001). The second item was the vigor of prescribed medication: Patients prescribed more vigorous treatments had lower DBP (p less than 0.005). Third, patient compliance was related to achieving a goal DBP of less than 90 mm Hg (p less than 0.05) and the product of prescribed vigor and compliance was highly associated with DBP response (p less than 0.0001). These results stand in contrast to those of previous studies that failed to detect associations between various other items of the care process and the outcome of antihypertensive care.

Adult↗
PubMedDate not supplied

Can simple clinical measurements detect patient noncompliance?

Measurement of patient compliance is essential if management of low compliance is to be performed efficiently. We assessed the value of several easily obtained clinical assessments compared to quantitative pill counts among 134 newly treated hypertensive male steelworkers during the first 6 months of their treatment with antihypertensive medication. Patient's self-reports obtained on structured interview correlated best with pill count compliance (r = 0.74, p less than 0.0001). Patients overestimated their compliance by an average of 17% but 90% of those who admitted to being noncompliant were found so. Qualitative urinary chlorthalidone and hydrochlorothiazide levels and changes in serum potassium, uric acid, and blood pressure also correlated with pill count compliance but were less accurate than interviews. Assessment of the patient's "health beliefs" and a variety of sociodemographic and health traits and perceptions did not provide useful information on compliance. Interviewing the patient is a simple and useful approach in assessing compliance with antihypertensive therapy.

Antihypertensive Agents↗