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Biomedical subjects

B Stewart

Publications and source records attributed to B Stewart.

At least 73 records · Page 4Linked to original sources
PubMed1995

Comparison of Milli-Q PF plus water with DEPC-treated water in the preparation and analysis of RNA.

The Milli-Q PF Plus water polishing system is equipped with high-purity ion and organic removal media and a capillary fiber ultrafiltration device. The system produces ultrapure water practically free of ribonuclease contamination. The necessity for diethyl pyrocarbonate (DEPC) treated solutions in RNA molecular biological procedures was tested by preparing RNA from a variety of tissues and tissue cultured cells using either DEPC-treated, autoclaved solutions or pure Milli-Q PF water dispensed directly from the system. Tissue sources included rabbit brain, heart, lung, liver, kidney, and bladder as well as cultured human corpus cavernosum smooth muscle cells (HCCSMC). RNA was prepared by solubilization in guanidinium isothiocyanate, phenol/chloroform extraction, and isopropanol precipitation followed by Northern blot analysis. Hybridization with fibronectin (approximately 7.6kb) and glyceraldehyde-3-phosphate dehydrogenase (1.2kb) revealed that water from a Milli-Q PF water system performed as well as DEPC-treated, autoclaved solutions. RNA stability at 37 degrees C was examined for various times using rabbit lung RNA in either DEPC-treated water or Milli-Q PF water. Intact RNA was detected after 6 hours in total RNA and by Northern blots hybridized with fibronectin. There was no significant difference in RNA degradation between DEPC-treated water or Milli-Q PF water. We conclude that Milli-Q PF water is an acceptable substitute to DEPC-treated water for the preparation of RNA and Northern blot analysis.

Animals↗
PubMed1995

Comparison of Milli-Q PF Plus water to DEPC-treated water in the preparation and analysis of RNA.

The Milli-Q PF Plus water-polishing system is equipped with high-purity ion and organic removal media and a capillary fiber ultrafiltration device. The system produces ultrapure water practically free of ribonuclease contamination. The necessity for diethyl pyrocarbonate (DEPC)-treated solutions in RNA molecular biological procedures was tested by preparing RNA from a variety of tissues and tissue-cultured cells using either DEPC-treated, autoclaved solutions or pure Milli-Q PF water dispensed directly from the system. Tissue sources included rabbit brain, heart, lung, liver kidney and bladder as well as cultured human corpus cavernosum smooth muscle cells. RNA was prepared by guanidinium isothiocyanate solubilization, phenol/chloroform extraction and isopropanol precipitation followed by Northern blot analysis. Hybridization with fibronectin (ca. 7.6 kb) and glyceraldehyde-3-phosphate dehydrogenase (1.2 kb) revealed that water from a Milli-Q PF water system performed as well as DEPC-treated, autoclaved solutions. RNA stability at 37 degrees C was examined for various times using rabbit lung RNA in either DEPC-treated water for Milli-Q PF water. Intact RNA was detected after 6 hours in total RNA and by Northern blots hybridized with fibronectin. There was no significant difference in RNA degradation between DEPC-treated water and Milli-Q PF water. We conclude that Milli-Q PF water is an acceptable substitute for DEPC-treated water for the preparation of RNA and Northern blot analysis.

Animals↗
PubMed1994

Iron status affects aluminum uptake and transport by Caco-2 cells.

To study the cell biology of aluminum uptake and transport in intestinal epithelia, an in vitro system based on intestine-derived Caco-2 cells grown in bicameral chambers was used. Aluminum was offered on the apical surface of Caco-2 cell monolayers as either aluminum citrate, aluminum lactate or aluminum nitrilotriacetate at 1:2 molar ratios, and the aluminum uptake into the cells and transport into the basal chamber were measured. The kinetics of cellular uptake of aluminum were different for the three chelators, although with all three chelators a final cellular concentration of approximately 50 nmol/mg cell protein was achieved. The total transport of aluminum into the basal chamber was greater for aluminum citrate and aluminum nitrilotriacetate than for aluminum lactate, suggesting that the chelator may direct aluminum into compartments from which aluminum is more easily transported. The iron status of the Caco-2 cells significantly affected both cellular uptake and transport of aluminum. Both iron-depleted and iron-overloaded cells exhibited significantly lower aluminum transport than cells of normal iron status. Aluminum loading of the Caco-2 cells had adverse effects on 59Fe2+ and 59Fe3+ transport compared with that of normal cells. These findings suggest that the Caco-2 cell line grown in bicameral chambers provides a model for studying aluminum transport, that aluminum uptake and transport to the basal chamber were affected by the chelator used, and that aluminum uptake and transport pathways are similar to those of iron.

Aluminum↗
PubMed1994

Teaching culturally diverse populations.

Nurses frequently interact with patients whose cultural beliefs are different from the nurses. Because health beliefs and values have a direct influence on health, the nurse must understand the culture of the patient when developing patient teaching programs. Ignorance of cultural differences can pose serious problems in patient education; without such knowledge nurses will alienate the very patients they are attempting to teach, and thereby run the risk of making recommendations in the teaching process that will be ignored. Only when the cultural dimensions of patient care are considered in planning can nurses claim that they are providing holistic and comprehensive care.

Communication Barriers↗
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↗