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Biomedical subjects

A Donald

Publications and source records attributed to A Donald.

At least 55 records · Page 3Linked to original sources
PubMed1990

Postmortem eyefluid analysis in dogs, cats and cattle as an estimate of antemortem serum chemistry profiles.

This study was carried out to determine the diagnostic usefulness of postmortem eyefluid analysis in estimating antemortem concentrations of serochemical constituents. A total of 31 cattle, 18 dogs and 22 cats were selected from routine elective euthanasia submissions to a diagnostic laboratory. For all cases, a biochemical profile, including determinations for electrolytes, glucose, urea, creatinine, enzymes, cholesterol, bilirubin, protein and osmolality was performed on antemortem serum, and postmortem aqueous and vitreous humors at 0 and 24 h incubation periods. The association between serum and postmortem eyefluid chemistry values was examined using simple linear regression. A strong correlation between serum and postmortem eyefluid urea and creatinine concentrations was demonstrated in the three species examined over a 24 h postmortem interval. We concluded that an accurate estimate of antemortem serum urea or creatinine can be made from the analysis of aqueous or vitreous fluid at necropsy. An estimation of antemortem serum electrolytes (including calcium in cattle) cannot be made with a high degree of accuracy due to the amount of variability in the relationship between serum and eyefluid electrolyte values. For large molecules such as proteins, enzymes, cholesterol and bilirubin there was very poor correlation between serum and eyefluid values.

Animals↗
PubMed1990

Ascariasis, respiratory diseases and production indices in selected Prince Edward Island swine herds.

The levels of production, ascarid burden and respiratory disease were measured on 15 purposively selected swine herds, and the relationships between the various measures of ascarid burden were examined. On each farm 30 randomly selected pigs were weighed and rectal fecal samples were collected at approximately 11, 15, 19 and 22 weeks of age, and at slaughter. Fecal ascarid-egg counts and duration of infection were combined to calculate a composite measure of ascarid burden called "lifetime burden". At the abattoir the carcass weight and levels of anteroventral pneumonia, atrophic rhinitis, and liver lesions were recorded for each hog. The number of ascarids in the small intestines were counted. Study hogs were marketed at an average of 189 +/- 22 days. The average dressed carcass weight was 77.0 +/- 5.9 kg and the mean average daily gain was 0.519 +/- 0.071 kg/day. The percent of hogs with ascariasis varied widely among farms, no matter what measure of ascariasis was used; the percent with intestinal ascarids at slaughter ranged from 0% to 96%, the percent that shed ascarid eggs during their lifetime ranged from 0% to 100%, and the range for hogs with liver lesions ranged from 27% to 100%. Of the hogs slaughtered, 82% had milk spot lesions, 32% shed ascarid eggs during their lifetime and 35% had intestinal ascarids. The latter had an average of 12 intestinal ascarids. Anteroventral pneumonia occurred in 55% of the slaughtered hogs and 9% had atrophic rhinitis scores of five. The percent of hogs per farm with pneumonia ranged from 17% to 96%. The percent of hogs per farm with atrophic rhinitis scores of five ranged from 0% to 57%.

Analysis of Variance↗
PubMed1990

Effect of ascariasis and respiratory diseases on growth rates in swine.

Growth rates, measures of ascarid burden, and the levels of anteroventral pneumonia and atrophic rhinitis at slaughter were determined for 352 hogs born between March 8 and March 28, 1987 on 15 farms located in Prince Edward Island. Regression analyses were used to determine associations between average daily gain (ADG) and independent variables controlling for sex, farm, and litters nested within farm. The regression model accounted for 75.4% of the variation in ADG. The number of intestinal ascarids at slaughter did not affect ADG. However, the "life-time burden" (a composite measure based on fecal egg counts and duration of infection) was associated with ADG (p less than 0.05) in a quadratic manner. Although heavy ascarid burdens decreased the growth rate of swine, the magnitude of the effect was minimal. The maximum improvement one could expect from reducing the ascarid burden on heavily infected farms would be less than 1%. Severe atrophic rhinitis and the presence of anteroventral pneumonia each had a detrimental effect on ADG (p less than 0.001). The corresponding reductions in mean ADG were 7.7% and 2.8% respectively. There was significant interaction between the effects of atrophic rhinitis and anteroventral pneumonia on ADG (p less than 0.05). Hogs with both anteroventral pneumonia and severe atrophic rhinitis had a 17.6% lower ADG than hogs with neither disease. There is much greater potential for improvement in ADG through control of respiratory diseases than through control of ascariasis.

Animals↗
PubMed1988

The statistical analysis of multiple binary measurements.

Epidemiologic studies often compare several groups of subjects for the presence or absence of a specified biological trait, where each subject in a group contributes two or more observations to the analysis. Examples occur in ophthalmologic studies, where each subject contributes observations on each of two eyes, and dental studies, where observations on each of several teeth may be contributed. Application of the standard Pearson chi-square test to such data is not valid, since the resulting sample observations are not statistically independent. In this paper we show how simple adjustments can be made to the Pearson chi-square statistic that adjust for the within-subject clustering. Application to other types of investigations involving clustered data is also discussed.

Adult↗
PubMed1988

Deep-vein thrombosis and continuous passive motion after total knee arthroplasty.

Seventy-five of 150 consecutive patients who underwent total knee arthroplasty had routine physiotherapy and seventy-five had continuous passive motion of the lower limb that had been operated on as well as routine physiotherapy. A pulmonary embolus did not develop in any patient, but about 40 per cent had thrombosis in the veins of the calf, whether passive motion had been administered or not. Radiographically, the deep-vein thrombosis was seen to extend into or proximal to the popliteal vessel in 5 per cent of the patients in each group. Sex, age, obesity, or a history of hypertension or diabetes did not influence the incidence of venous thrombosis, but there was a higher incidence in patients in whom cement was used for fixation of the total knee components, irrespective of the use of continuous passive motion of the limb.

Adult↗
PubMed1987

Interobserver variation in computed tomography of the brain.

As part of the University of Western Ontario Dementia Study, the computed tomographic brain scans of 16 patients were reviewed by three neuroradiologists. The size of the ventricles and sulci were rated using a six-point scale. Infarction and white matter changes were assessed in accordance with specified criteria. The interobserver correlations in this small series were statistically significant in 17 of 20 items, and good or acceptable for infarction, leuko-araiosis, and ventricular size. It is suggested that the use of rigid criteria for the definition of abnormality helps to promote interobserver agreement.

Brain↗
PubMed1987

Vascular risk factors and leuko-araiosis.

Leuko-araiosis was found in 49 of 140 demented patients compared with 12 out of 110 control subjects. Thirty-one of 95 patients with dementia of the Alzheimer's type had leuko-araiosis. A history of stroke was four times more frequent in patients with leuko-araiosis than in those without leuko-araiosis (17.4% and 4.4%, respectively). It occurred in 25% of controls with leuko-araiosis compared with only 2% of those without leuko-araiosis. Mean systolic blood pressure was associated with leuko-araiosis. No association was found for diastolic blood pressure, myocardial infarction, angina, diabetes, or carotid bruits. On logistic regression analysis, the strong association between dementia and leuko-araiosis was mainly explained by a history of stroke. There are common factors in leuko-araiosis and stroke, but stroke alone does not account for leuko-araiosis.

Aged↗
PubMed1987

Adjustments to the Mantel-Haenszel chi-square statistic and odds ratio variance estimator when the data are clustered.

Dependence between observations on a dichotomous variable renders invalid the usual chi-square tests of independence and inflates the variances of parameter estimates. Such a situation occurs, for example, when subjects consist of members of the same family or with repeated observations on the same person. In this paper we describe methods of measuring the extent of correlation (or clustering). We also develop methods of adjusting the Mantel-Haenszel chi-square test statistic and the variance of the Mantel-Haenszel estimate of a common odds ratio in sets of 2 X 2 contingency tables.

Analysis of Variance↗
PubMed1983

Comparative effects of propranolol and verapamil alone and in combination on left ventricular function and volumes in patients with chronic exertional angina: a double-blind, placebo-controlled, randomized, crossover study with radionuclide ventriculography.

With the use of equilibrium radionuclide ventriculography the effects on left ventricular (LV) function of 160 mg oral propranolol daily and 360 mg verapamil daily alone and in combination were compared in 18 patients with chronic exertional angina. A randomized, double-blind, placebo-controlled, crossover protocol was used. The reduction in exercise rate-pressure product induced by the combination (118 +/- 28 mm Hg/min) was significantly greater (p less than .05) than that by propranolol (135 +/- 27 mm Hg/min) or verapamil alone (163 +/- 28 mm Hg/min). In patients at rest, neither single nor combined therapy altered global or regional left ventricular ejection fractions (EFs). Verapamil, but not propranolol, increased (p less than .05) cardiac volumes of resting subjects; used in combination, no further increase in LV volume occurred. With placebo, exercise global EF did not decrease from the level at rest and therefore no drug effect could be demonstrated for this parameter of LV function. By an evaluation of normalized regional EF measurements the combination was shown to reduce exercise-induced hypokinesis (placebo 52 +/- 20%, combination 61 +/- 23%; p less than .01). No significant improvement was noted with propranolol or verapamil alone; only the combination prevented a significant increase in end-systolic and end-diastolic volumes during exercise. Thus, propranolol and verapamil, used alone in moderate doses, exert no beneficial effect on exercise LV function as measured by EF and volume changes, and resting function deteriorates slightly with verapamil.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗