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Biomedical subjects

B Stewart

Publications and source records attributed to B Stewart.

At least 19 recordsLinked to original sources
PubMed1995

Sexual dimorphism in the metabolic response to the calcium channel antagonists, diltiazem and clentiazem, by hyperlipidemic JCR:LA-cp rats.

The JCR:LA-cp rat is obese, insulin resistant, and hypertriglyceridemic. The obese male rats spontaneously develop atherosclerosis and ischemic myocardial lesions that are prevented by treatment with the calcium channel antagonist, nifedipine. Male and female JCR:LA-cp rats were treated with the calcium channel antagonist, diltiazem, and a closely related compound, clentiazem (at 30 mg/kg). Clentiazem, but not diltiazem, caused a significant increase in body weight of both sexes in the presence of decreased food consumption. Serum triacylglycerols were decreased by half by both drugs in male rats only, reflecting decreased very-low-density lipoprotein (VLDL) secretion. Females did not respond with lower concentrations of triacylglycerol (although VLDL secretion rate was decreased) and showed increased concentrations of cholesterol in the high-density lipoprotein (HDL) fraction. Diltiazem-treated male rats showed decreased VLDL particle size, together with a shift to shorter-chain fatty acids in the triacylglycerols. This effect was not seen with clentiazem treatment. There was no effect on insulin and glucose metabolism in these insulin-resistant animals. Calcium channel antagonists have complex metabolic effects in the hypertriglyceridemic rats, with highly beneficial hypolipidemic effects in the males that are not seen in the females. The sexual dimorphism of these responses is sex linked, but appears not to be due to the steroid sex hormones. These results suggest caution in the chronic treatment of human females with these agents and the importance of detailed human studies in females and individuals with the insulin-resistant/hypertriglyceridemic/obese syndrome.

Animals↗
PubMed1995

Solid organ procurement from burn patients.

With the increasing success or organ transplantation and the consequent increasing scarcity of suitable organs, many traditional contraindications to organ procurement are being reconsidered. One such traditional contraindication to organ procurement is burn injury. We report a case of successful multiorgan procurement from a child with an extensive burn and propose guidelines for solid organ harvest from burn patients.

Burns↗
PubMed1995

Normal sweat chloride values do not exclude the diagnosis of cystic fibrosis.

Since its introduction in 1959, the sweat test has remained the "gold standard" diagnostic test for cystic fibrosis (CF). It is apparent that CF encompasses a wide spectrum of disease, from meconium ileus and severe respiratory compromise in infants to the presentation of mild pulmonary symptoms and no evidence of gastrointestinal disease in adults. In patients with lung disease that might otherwise be consistent with CF, normal sweat chloride (Cl-) values have tended to exclude the diagnosis. In this report we describe two patients from two families with the compound heterozygotic CF mutations delta F508/3849 + 10 kb C-->T. These patients had mild manifestations of disease, including clinical pancreatic sufficiency (normal growth without pancreatic enzyme supplementation) and absence of azoospermia. Sweat Cl- values were in the normal range. However, both patients developed bronchiectasis, progressive obstructive lung disease, and colonization with Pseudomonas. The diagnosis of CF was made using nasal transepithelial voltage measurements and genotyping. These cases emphasize the need to maintain a high index of suspicion of CF in atypical cases, and to pursue alternative diagnostic tests to confirm a diagnosis of CF suspected on clinical grounds, despite normal sweat test results.

Adult↗
PubMed1992

The use of a videotaped questionnaire for studying asthma prevalence. A pilot study among New Zealand adolescents.

OBJECTIVE: To examine the feasibility of measuring asthma prevalence by means of an audio-visual presentation of asthma symptoms and signs (video questionnaire) and to compare this technique with a standard written questionnaire for predicting bronchial hyperresponsiveness. DESIGN: A cross-sectional study comparing the ability of a video questionnaire and a written, interviewer administered questionnaire to predict bronchial hyperresponsiveness. Bronchial responsiveness was measured with hand held nebulisers. SETTING: Community survey of a New Zealand rural secondary school. SUBJECTS: A total of 456 adolescent school children aged 12-19 years (mean 15.5 years). OUTCOME MEASURES: Comparison of the sensitivity and specificity of a standard questionnaire versus a video questionnaire for bronchial hyperresponsiveness. RESULTS: The technique was easy to administer in the community setting. Overall sensitivity and specificity for the prediction of bronchial hyperresponsiveness were similar for the video and interviewer administered questionnaires. CONCLUSIONS: This new technique is easily used in the community setting, and gives predictions of bronchial hyperresponsiveness similar to those of a standard interviewer administered questionnaire. Further examination of the technique in comparisons of asthma prevalence among different populations is planned.

Adolescent↗
PubMed1992

Role strain and depression in employed married Black mothers.

During the past several decades, the rate of participation in the labor force among married women with children has increased steadily. This trend coincides with an increase in the rate of reported psychological distress among women and an increase in researchers' interest in the psychological consequences of married mothers in the work force. Black women have historically and in significant numbers worked outside the home. The authors discuss the major concerns of employed Black mothers, identify areas where mental health professionals might intervene and identify coping strategies for Black women managing multiple roles.

Adaptation, Psychological↗
PubMed1992

Optimized spectrophotometric determination of aldehyde dehydrogenase activity in erythrocytes.

We describe a reliable and sensitive semiautomated spectrophotometric assay of aldehyde dehydrogenase (ALDH; EC 1.2.1.3) activity in erythrocytes. The hemolysate can be stabilized with sucrose, and the technique involves only microliters of hemolysate on a centrifugal analyzer. The use of microcolumns to remove interfering hemoglobin is avoided, and reproducibility of the assay has been improved by manipulating the inherent lactate dehydrogenase activity of erythrocytes by adding lactate and oxalate to the reaction mixture. These modifications have decreased the analytical imprecision of the assay, allowing a better appraisal of aldehyde dehydrogenase activity in erythrocytes as a biological marker of excess alcohol consumption. Erythrocytic ALDH activity was significantly less in 40 alcoholics than in 145 teetotallers (median activity 128 vs 219 mU/g of hemoglobin, respectively; P = 0.0001), indicating the potential of this assay as a useful marker of excess alcohol consumption.

Acetaldehyde↗
PubMed1991

Activated CD-8 cells and HLA DR expression in alcoholics without overt liver disease.

Lymphocytes from alcoholics without liver disease were immunophenotyped by flow cytometry immediately after admission for detoxication and again after 4 to 10 days of abstinence. We found a small but significant elevation of T lymphocytes at admission compared to controls and decreases in the numbers of B cells and natural killer cells in many patients. A significant elevation of activated T cells was confirmed. The ratio of activated T cells to activated non-T cells was also substantially increased, but declined slightly during early withdrawal. The increase in activated T cells was due mostly to increased numbers of activated CD8hi cells. These activation changes did not revert toward normal as quickly as the other changes and may represent an indication of immune damage at a preclinical stage. An additional finding of interest was a substantial decrease in the expression of HLA DR on CD4+ and non-T cells. The significance of this decrease is not known, but we speculate that it may result in a decline in the efficiency of antigen presentation.

Adult↗
PubMed1991

Superior mesenteric artery aneurysms: a case report.

Aneurysms of the superior mesenteric artery (SMA) are rare, accounting for 8% of visceral artery aneurysms. Aneurysms at the site are very liable to rupture, irrespective of size, and may be difficult to manage even in the elective situation. The fact that 50-60% of SMA aneurysms are mycotic has important implications in the selection of the appropriate surgical procedure. In this paper we report a case of an SMA aneurysm diagnosed at the time of impending rupture and treated successfully. The aetiology, mode of presentation, diagnosis and management of SMA aneurysms are discussed.

Adult↗
PubMed1990

Cognitive specificity and positive-negative affectivity: complementary or contradictory views on anxiety and depression?

A principal factor analysis, conducted on a mixed psychiatric outpatient sample (N = 470), identified both common and specific dimensions underlying anxiety and depression. Although an initial single-factor extraction accounted for a significant proportion of variance in cognitive and symptom measures of anxiety and depression, a two-factor solution, in which anxiety and depression formed separate dimensions, proved to be the better solution. MANOVAS performed on pure depressed, pure anxious, and mixed anxious/depressed subgroups provided evidence of a specific cognitive profile for anxiety and depression. The mixed subsample evidenced greater severity, a mixed cognitive and symptom profile, and character traits that may indicate increased vulnerability to psychological disturbance. Results are discussed in terms of Beck's (1976) cognitive content-specificity hypothesis and the positive-negative affect model (Watson & Tellegen, 1985).

Adaptation, Psychological↗
PubMed1989

Biliary atresia: early determination of prognosis.

Analyses of bile bilirubin during the first month after Kasai operations, and of the liver biopsies obtained at the time of initial surgery, were done in 67 patients with biliary atresia. Bilirubin excretion (milligrams per day) was determined as the product of the bile volume and its concentration. Operative liver biopsies were evaluated for fibrosis, bile duct proliferation, bile stasis, giant cell transformation, and parenchymal degeneration; the severity of each abnormality was graded on a scale of 0 to 4. A forward stepwise regression procedure using the Cox proportional hazards model identified the relationship between survival and covariants. Thirty-nine of 67 patients died. Of these, 38 excreted less than 6 mg of bilirubin per day during the first postoperative month. The other patient died of a coexisting anomaly. Nine other patients who excreted less than 6 mg of bilirubin per day are alive but are either jaundiced or awaiting transplantation. Nineteen patients who excreted greater than or equal to 6 mg of bilirubin per day are alive (mean follow-up, 61 months) with normal or near-normal liver function. The severity of liver fibrosis, bile duct proliferation, and bile stasis did not correlate with survival, whereas giant cell transformation and parenchymal degeneration were highly significant (P less than or equal to .000 and P less than or equal to .0003, respectively). Twenty-six infants with grade 1-4 giant cell transformation or grade 2-4 parenchymal degeneration had a mean survival of 11 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Bile↗
PubMed1989

Cerebral vasculitis and hemorrhage in an adolescent taking diet pills containing phenylpropanolamine: case report and review of literature.

Phenylpropanolamine is consumed by millions of persons annually and is sold in varying dosages and combinations for different ailments. Adolescents are an especially susceptible group influenced by its action as an anorexiant. During the past 6 years, several cases have been reported of patients in whom intracerebral hemorrhage developed, with and without concomitant angiographic evidence of vasculitis, after taking phenylpropanolamine. In this report, the 11th documented case of phenylpropanolamine-associated intracerebral hemorrhage with vasculitis is described. This is the first case in an adolescent following the ingestion of an overdose of diet-aid pills. Cases of intracerebral hemorrhage with vasculitis have also been described in users and abusers of amphetamine, methamphetamine, and ephedrine, all sympathomimetics with chemical structures similar to that of phenylpropanolamine. This report should alert pediatricians to the potential use by their patients of nonprescription medications containing phenylpropanolamine whenever unexplained acute cerebral symptoms are present.

Adolescent↗
PubMed1988

Evaluation of laboratory methods for the classification of oxacillin-resistant and oxacillin-susceptible Staphylococcus aureus.

The purpose of this study was to examine the efficacy of the oxacillin disk diffusion test and the methicillin and oxacillin agar screen tests as predictors of oxacillin resistance as defined by the reference broth microdilution method. A total of 444 clinical isolates of Staphylococcus aureus collected from individual patients over a four-year period were tested by (1) the oxacillin disk diffusion test, with particular attention to the presence of fine growth of a resistant subpopulation within the zone of inhibition (Ox Grow interpretive criteria); (2) the agar screen method using agar plates with 4% NaCl and either 6 mg/L oxacillin or 10 mg/L methicillin; and (3) the oxacillin and methicillin broth microdilution test methods with 2% NaCl supplementation. Overall, 62 (14%) isolates were resistant and 382 (86%) isolates were susceptible to oxacillin with the use of the reference broth microdilution system. The results indicate that the disk diffusion test with the use of the Ox Grow criteria had a high sensitivity (94%) and negative predictive value (98%) but a low specificity (67%) and positive predictive value (32%) when compared with the reference broth dilution test. Similarly, the agar screen tests had a high sensitivity (95-97%) and negative predictive values (99%) but low specificity (64-74%) and positive predictive values (30-37%). These data indicate that the agar screen tests and the oxacillin disk test with the use of the Ox Grow interpretive criteria may be useful as screening tests for detecting resistance to the penicillinase-resistant penicillins but that all resistant isolates should be confirmed by the reference broth dilution method because of the large number of false-resistant screening test results.

Bacteriological Techniques↗