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Biomedical subjects

D Dale

Publications and source records attributed to D Dale.

31 records · Page 2Linked to original sources
PubMed1994

Parental opinions about attending parent support groups.

Parent support groups are often a routine part of the services provided to families who have children with special health care needs. Often times, however, the groups are poorly attended, despite expressions of interest from parents. A survey of 45 families was conducted to examine who participates, why, and what factors encourage attendance. This article describes the survey responses and offers suggestions regarding utilization of the results for those planning parent support groups.

Adult↗
PubMed1993

Use of surnames to identify individuals of Chinese ancestry.

The objectives of this study were to develop and test surname lists for identifying Chinese ancestry. The Ontario all-cause mortality database for the period 1982-1989 was randomly split into source and test data sets. Frequencies by birthplace were compiled for each surname in the source data set, by sex, and the surnames were weighted based on their positive likelihood ratios. Lists of Chinese surnames were then assembled based on varying cutoff levels, and screening performance indicators for each list were calculated, including sensitivity, specificity, positive and negative predictive values, post-test odds, positive likelihood ratio, and yield. The internally generated lists were evaluated in the test data set. Results indicated that surnames have a good potential to identify individuals of Chinese origin. In the source data set, at a cutoff level of 100 for males (217 surnames) and females (210 surnames), both sensitivity and the positive predictive value of the surname lists for males and females were very high, above 80%, and the positive likelihood ratio was above 600. In the test data set and using the same surname lists, the sensitivity, positive predictive value, and positive likelihood ratio remained at a high level: 73%, 81%, and 603, respectively, for males; and 73%, 84%, and 772, respectively, for females. Various scenarios and their methodological implications are discussed.

China↗
PubMed1992

Postmenopausal steroid replacement with micronized dehydroepiandrosterone: preliminary oral bioavailability and dose proportionality studies.

OBJECTIVES: Because dehydroepiandrosterone may protect against neoplasia, osteoporosis, and cardiac disease, we investigated the bioavailability of oral micronized dehydroepiandrosterone, anticipating its adjunctive use in postmenopausal steroid replacement. STUDY DESIGN: Eight postmenopausal women randomly received either a placebo or 150 or 300 mg of oral micronized dehydroepiandrosterone in a lipid matrix. Serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, testosterone, and estradiol were measured periodically over the 12 hours after each dose. All treatments, all doses, and mean serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, and testosterone were compared with analysis of variance for repeated measures and Newman-Keuls a posteriori test of statistical significance. RESULTS: Mean peak steroid concentrations after 150 mg (300 mg) doses were dehydroepiandrosterone 1617 (2639) ng/dl, 7 (11.5)-fold above placebo; dehydroepiandrosterone S 1185 (1688) micrograms/dl, 14 (20)-fold above placebo; and testosterone 183 (311) ng/dl, 4 (7)-fold above placebo. Estradiol concentrations remained less than 20 pg/ml, but androgen concentrations rose by 1 hour and remained elevated through the twelfth hour. Peak androgen concentrations and areas under the curves exhibited proportionality with both doses. A testosterone radioimmunoassay with celite chromatography revealed a 300% overestimation for testosterone in the direct-assay method used in this study. Thus after appropriate readjustment maximum testosterone concentrations were observed consistently within physiologic premenopausal ranges after the 150 mg dose. CONCLUSIONS: Micronized dehydroepiandrosterone may provide a steroidal postmenopausal replacement that is adjunctive to estrogens and worthy of further investigation.

Administration, Oral↗
PubMed1990

Diffusivity dependence of multiple-breath washouts of lung periphery.

Subpleural concentrations of He and SF6 were measured during multiple-breath washouts from isolated dog lungs. Tidal volume, inspiratory flow, and frequency were in the normal range of canine ventilation. For each gas, there was a local minimum in concentration during inspiration (Cinsp) and a local maximum in concentration during exhalation (Cexp). SF6 exhibited a deeper inspiratory trough than He for each breath of every washout. For large tidal volumes (10-20 ml/kg), Cexp approximated a single exponential decay and He was cleared more rapidly than SF6. For small tidal volumes (2.5 ml/kg), Cexp was multiexponential and SF6 was cleared more rapidly than He. Cinsp/Cexp (a measure of the depth of the inspiratory trough) and the kinetics of Cexp decay were determined for washouts using a tidal volume of 10 and 20 ml/kg and different inspiratory flows. Under all conditions, an increase of inspiratory flow resulted in a deeper inspiratory trough for both He and SF6. For washouts using 10 ml/kg and 60 breaths/min, an increase of inspiratory flow increased the clearance of both gases. In washouts using lower ventilatory frequencies, gas clearance was independent of inspiratory flow. These findings are contrary to predictions of contemporary models of convection and diffusion in the lung. This study suggests that convective axial mixing and radial diffusion in the airways are important determinants of pulmonary gas transport.

Animals↗
PubMed1990

Inspiratory flow rate and dead space in dogs.

It is generally accepted that a stationary concentration front is established in the tracheobronchial tree during the inspiratory phase of single- and multiple-breath washouts. The anatomic position of this front, which is determined by the balance between diffusive flux toward the airway opening and convective flux toward the periphery, is frequently used to predict the effects of molecular diffusivity and inspiratory flow rate on dead space. Although there is substantial experimental evidence supporting the predictive effect of molecular diffusivity, there is little evidence regarding the effect of convective flow. This study confirmed the predictions for the effects of molecular diffusivity but contradicted those for the effects of inspiratory flow. We measured dead space by multiple- and single-breath inert gas washout techniques and also measured physiological dead space in dogs for inspiratory flow rates of 10-71 ml.kg-1.s-1. None of the three measures of dead space increased over the entire range of flow rate, as predicted by contemporary gas transport models. A possible explanation for these findings is that axial dispersion coefficients in the anatomic region where stationary fronts are believed to develop (respiratory bronchioles and alveolar ducts) significantly increase with convective flow rate rather than remain equal to molecular diffusivity.

Animals↗