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Biomedical subjects

G Anderson

Publications and source records attributed to G Anderson.

At least 217 records · Page 12Linked to original sources
PubMed1992

Pericapillary collagen in the human thymus: implications for the concept of the 'blood-thymus' barrier.

The deposition of collagen in the walls of capillary-size blood vessels was studied in 95 human thymuses with respect to the site of deposition, extent of the change and relation to age and degree of involution. When examined by electron microscopy the collagen was found to be situated between the 2 basement membranes of the so-called 'double-layered' capillaries characteristic of the thymus of many species. This results in the formation of substantial 'collars' of collagen around a proportion of the blood vessels examined. Few such collars are seen before birth, but their number and thickness increase markedly during the 1st year of life. The relationship of these changes to the degree of involution is less apparent. The significance of these changes to thymic structure and function is discussed in relation to cell traffic through the thymus and the postulated 'blood-thymus barrier', the existence of which is seen to be in some doubt.

Aging↗
PubMed1992

Basic epidemiologic and statistical methods in clinical research.

Various study designs and approaches to statistical analysis in clinical research have their own underlying rationales and limitations for interpretation. This information is presented in an intuitive and accessible manner, relying minimally on basic algebra. Epidemiologic concepts of study design and interpretation, bias and confounding, hypothesis testing, and sample size and power are explained. Statistical tests and their appropriate applications are discussed for mean comparisons (t tests and ANOVA), percentages (chi-square), survival analysis, and correlation and regression. Applicable nonparametric tests are also introduced.

Carcinoma, Transitional Cell↗
PubMed1992

Wegener's granuloma. A series of 265 British cases seen between 1975 and 1985. A report by a sub-committee of the British Thoracic Society Research Committee.

In order to describe the British experience of Wegener's granulomatosis Hospital Activity Analysis was used to collect cases diagnosed in England, Wales and Scotland between 1975 and 1985. Where possible clinical details, histological material and chest radiographs were obtained. Two hundred and sixty five patients were considered to have Wegener's granulomatosis. In 109 a single pathologist confirmed the diagnosis by finding both granulomas and vasculitis in biopsy material. The diagnosis was made on clinical grounds or clinical grounds together with histological diagnosis in the local hospital in 156 patients. Wegener's granulomatosis was confined to the lung or upper respiratory tract in 22 per cent of patients and renal disease occurred in 58 per cent. Laboratory tests showed a pattern of mild anaemia, polymorph leucocytosis, eosinophilia and an elevated ESR and hypergammaglobulinaemia, with no specific pattern of changes. Histological confirmation was most frequently obtained by examination of nasal biopsy specimens, but multiple biopsies were often required. Renal biopsies showed focal proliferative glomerulonephritis but granulomatous glomerulonephritis was uncommon. Of available chest radiographs 61 per cent were abnormal, large opacities being most common. Small irregular opacities were found less often and other abnormalities were uncommon. Treatment varied widely and 10 per cent of patients received no drug therapy. This large series illustrates that even without specific treatment, patients with Wegener's granulomatosis can survive for several years and with modern treatment survival for more than a decade is possible. Conclusions about the effectiveness of the various therapies cannot be drawn from this retrospective study. Renal failure and disseminated vasculitis were the commonest causes of death; death was considered to result from complications of treatment with cytotoxic drugs or prednisolone in 6 per cent of patients.

Adolescent↗
PubMed1991

Atrial natriuretic peptide response to cardioversion of atrial flutter and fibrillation and role of associated heart failure.

Plasma atrial natriuretic peptide (ANP) concentrations were measured before and 1 hour after cardioversion in 40 patients (27 with atrial flutter and 13 with atrial fibrillation) admitted for elective cardioversion. Fourteen (11 with atrial flutter and 3 with atrial fibrillation) had clinical evidence of congestive heart failure (CHF). Conversion to sinus rhythm was successful in 39 patients. The mean ANP concentration in the entire group decreased after cardioversion from 38 +/- 4 to 17 +/- 2 pmol/liter (p less than 0.001). In the subgroup with CHF, the ANP level, which was not significantly higher than that in the group without CHF, decreased from 47 +/- 8 to 19 +/- 3 pmol/liter (p less than 0.01). Neither mode of cardioversion (spontaneous 1, pharmacologic 2 and direct-current countershock 36) nor associated CHF influenced ANP response to cardioversion. One patient with atrial flutter and "failed cardioversion" had unchanged ANP level. The decrease after cardioversion in ANP concentration correlated with its control level (r = 0.88, p less than 0.001) but not with the decrease in heart rate. The ANP level in patients with atrial fibrillation was 45 +/- 9 vs 38 +/- 5 pmol/liter in those with atrial flutter (difference not significant). Arrhythmia duration, left atrial size, and ventricular rate or arterial blood pressure did not correlate with ANP concentration in any subgroup. It is concluded that (1) the ANP level is elevated comparably in patients with both atrial flutter and fibrillation regardless of the presence or absence of CHF; and (2) the level decreases, independent of the mode of cardioversion or presence of CHF, promptly after successful cardioversion.

Aged↗
PubMed1991

Characterization of a cell line derived from rhabdoid tumor of kidney.

Rhabdoid tumor of kidney (RTK) is a rare, highly malignant childhood neoplasm of uncertain histogenesis. Several recent studies have described considerable histochemical heterogeneity among cases of RTK, with confusing combinations of epithelial, mesenchymal, myogenous, and neuroepithelial markers in some tumors. The present study characterizes the histology, ultrastructure, histochemistry, cytogenetics, and oncogene expression in a cell line derived from RTK. The surgical specimen, nude mouse xenograft, and cell cultures demonstrated characteristic intermediate filament whorls by electron microscopy and expressed vimentin (diffusely) and cytokeratin (focally, in hyaline cytoplasmic inclusions) without detectable desmin, Thy-1, or epithelial membrane antigen. S-100 protein was absent in the surgical specimen and heterotransplant, and was seen very weakly and focally in the cell cultures. Light microscopic features of cultures were unchanged by several compounds (tissue plasminogen activator, nerve growth factor, cyclic adenosine monophosphate) which induce differentiation of some other pediatric neoplasms. The growth factor requirements of RTK cultures indicate a cell with mesenchymal features. Insulin-like growth factor-2 mRNA was detected in the RTK and in three Wilms' tumors also studied. Unlike most Wilms' tumors, RTK expresses the c-myc rather than the N-myc oncogene.

Desmin↗
PubMed1991

Clarithromycin in the treatment of community-acquired lower respiratory tract infections.

Clarithromycin is a macrolide with in-vitro activity against the organisms usually responsible for community-acquired pneumonia and acute exacerbations of chronic bronchitis. Three double-blind controlled studies each in pneumonia and chronic bronchitis are reviewed. In pneumonia clarithromycin is as effective as erythromycin and in acute-on-chronic bronchitis is as effective as ampicillin. In an open study of 46 patients with pneumonia due to Legionella pneumophila, resolution occurred in 93% with no deaths. The incidence of adverse events was 20% in 3437 patients. These were rarely severe. Clarithromycin is better tolerated than erythromycin and its twice daily dosage is likely to lead to better patient compliance.

Administration, Oral↗
PubMed1991

Utilization management: a literature review for Canadian health care administrators.

Utilization management (UM), the attempt to measure, understand and reduce inappropriate hospital use, has been in development for over 20 years. It is an outgrowth of two related phenomena: (1) the increasing responsibility of large institutional third party payers for health care costs and the increasing demand of those payers for accountability; and (2) in Canada, particularly, the debate surrounding the adequacy of hospital funding and the perceived inadequacy of cost control using global budgeting. Given the interest in UM, hospital administrators, provincial and federal associations representing hospitals, hospital employees and physicians would find a review of UM programs useful in terms of what is known about their effectiveness, and the specific initiatives in Canada. The authors underscore the critical need for formal evaluation of UM programs; to date there has been little systematic research into issues related to its implementation and impact. This issue is particularly pertinent because UM programs have not been widely implemented in Canada.

Canada↗
PubMed1991

Effects of interparental violence on the psychological adjustment and competencies of young children.

Preschool children (N = 107) were divided into 4 groups on the basis of maternal report; home and shelter groups exposed to verbal and physical conflict, a home group exposed to verbal conflict only, and a home control group. Parental ratings of behavior problems and competencies and children's self-report data were collected. Results show that verbal conflict only was associated with a moderate level of conduct problems: verbal plus physical conflict was associated with clinical levels of conduct problems and moderate levels of emotional problems; and verbal plus physical conflict plus shelter residence was associated with clinical levels of conduct problems, higher level of emotional problems, and lower levels of social functioning and perceived maternal acceptance. Findings suggests a direct relationship between the nature of the conflict and residence and type and extent of adjustment problems.

Adaptation, Psychological↗
PubMed1991

Detection of anti-A in neonatal serum.

The thirteenth edition of the standards of the American Association of Blood Banks did not require the use of A1 red cells (RBCs) or an indirect antiglobulin test (IAT) to detect anti-A in neonatal serum, whereas the fourteenth edition mandates both. The present study was conducted to help document the need for these changes. Incomplete expression of the A antigen in neonatal patients can contribute to the accumulation of unabsorbed maternal anti-A that is capable of mediating the immune destruction of transfused adult RBCs. Sera from 50 group A neonatal infants of group O mothers were tested for anti-A by using RBC segments of A1 and A2 units of AS-1 RBCs less than 14 days old and also with A1 reagent RBCs. Of 22 sera in which anti-A was detected by RBCs from the A1 units with an IAT, anti-A was detected by RBCs from the A2 unit in only 1 and by the reagent RBCs in 17. In 19 (86%) of the 22 neonatal patients in whose sera anti-A was detected, the antibody was found only with the use of anti-human globulin in the IAT. It is concluded that testing to detect circulating anti-A in neonatal patients should include an IAT, and that it is preferable to use A1 RBCs for the initial evaluation.

ABO Blood-Group System↗
PubMed1991

Red cell survival studies in a patient with anti-Tca.

A radiolabeled, allogenic red cell survival study was performed on a patient who lacked the Cromer-related antigen Tca and who had developed the corresponding antibody. Red cell survival was 92% at 1 hour and 88% at 24 hours. Monocyte monolayer assays (MMA) and IgG subclass determinations were performed on samples from: (1) 1965, the period of initial antibody formation; (2) approximately two years before the red cell survival study; and (3) four months after the study. All samples reacted w+ to 1+ by the antiglobulin test. The earliest sample contained IgG1, IgG2, and IgG4 anti-Tca. Because there were 20.5% reactive monocytes in the MMA (normal range 0-3%), this antibody may have produced extravascular red cell destruction. In contrast to the initial example, the samples before and after the red cell survival study both contained IgG2 and IgG4 subclasses with 1.3% and 2.2% MMA reactivity, respectively. The current pattern of antibody subclass, the lack of reactivity in the MMA, and a red cell survival of 88% at 24 hours indicate that short-term transfusion support would have been well tolerated. This contrasts to the in vitro results obtained with the earliest sample, which suggest a clinically significant antibody. This appears to be the first report of a red cell alloantibody that remained serologically reactive but underwent a loss of its IgG1 fraction, which appeared capable of red cell destruction based on the MMA results.

Aged↗
PubMed1991

A comparative safety and efficacy study of clarithromycin and erythromycin stearate in community-acquired pneumonia.

The efficacy and tolerance of clarithromycin and erythromycin stearate in the treatment of community-acquired pneumonia were compared in a multicentre, double-blind randomized trial. Two hundred and eight adult patients were randomized to receive either clarithromycin 250 mg 12-hourly (96 patients) or erythromycin stearate 500 mg 6-hourly (112 patients), each for 14 days. One hundred and eight patients were evaluable for efficacy, 64 receiving clarithromycin and 44 erythromycin stearate. There was no significant difference between the two groups in terms of clinical cure (52% for clarithromycin, 40% for erythromycin) or clinical success (clinical cure and improvement; 89% for clarithromycin, 98% for erythromycin stearate), or radiological response (90% for both groups). An intention-to-treat analysis, including all patients entering the study revealed significant differences in favour of clarithromycin. The clinical cure rate after two weeks of treatment was 45% in those who received clarithromycin compared with 25% in the erythromycin stearate group (P = 0.003), whilst improvement in cough was observed in 97% and 80% of patients receiving clarithromycin and erythromycin stearate, respectively (P = 0.07). Adverse effects, mainly gastrointestinal, caused discontinuation of treatment in 4% (4/96) patients in the clarithromycin group in comparison with 19% (21/112) treated with erythromycin stearate (P less than 0.01). These results demonstrate that clarithromycin twice daily is at least as effective as four times daily erythromycin stearate for the treatment of community-acquired pneumonia and is better tolerated.

Adult↗
PubMed1991

CARET, the beta-carotene and retinol efficacy trial to prevent lung cancer in asbestos-exposed workers and in smokers.

CARET is a two-armed, double-blind, randomized chemo-prevention trial to test the hypothesis that oral administration of beta-carotene 30 mg/day plus retinyl palmitate 25,000 IU/day will decrease the incidence of lung cancer in high-risk populations: heavy smokers and asbestos-exposed workers who have smoked. The agents combine anti-oxidant and nuclear tumor suppressor mechanisms. Fastidious monitoring for possible side effects is facilitated by inclusion of a Vanguard population. As of 31 December 1990, 6,105 participants of the 18,000 needed have been randomized in the trial. Efficacy results are expected in 1999.

Aged↗
PubMed1991

Does the substitution of cisplatin in a standard four drug regimen improve survival in small cell carcinoma of the lung? A comparison of two chemotherapy regimens.

Ninety five patients with small cell carcinoma of the lung were randomly assigned to one of two chemotherapy regimens (VACE or CVACE), each consisting of six cycles at three week intervals. The VACE regimen consisted of six cycles of vincristine 1.2 mg/m2, doxorubicin 40 mg/m2, and cyclophosphamide 700 mg/m2 on day 1 plus etoposide 110 mg/m2 daily for three days. The CVACE regimen was identical to the VACE regimen for cycles 3 and 4; cycles 1, 2, 4, and 6 consisted of etoposide 110 mg/m2 for three days plus cisplatin 100 mg/m2 with mannitol diuresis on the second day. Forty eight patients received VACE and 47 CVACE. Side effects resulted in withdrawal of four patients receiving VACE and six receiving CVACE. Three deaths were attributed to VACE and one to CVACE. Median survival did not differ between the two treatments overall, though there was a small increase in median survival in partial responders receiving CVACE. It is concluded that replacing four of the six cycles of VACE (vincristine, doxorubicin, cyclophosphamide, and etoposide) with etoposide and cisplatin conferred no overall advantage.

Adult↗
PubMed1991

The frequency of multiple personality disorder among psychiatric inpatients.

OBJECTIVE: A 2-year study was undertaken to determine the frequency of multiple personality disorder among general adult psychiatric inpatients. METHOD: All individuals admitted to two 23-bed acute care wards in a teaching hospital in Winnipeg, Man., were screened with the Dissociative Experiences Scale. Individuals with prior diagnoses of multiple personality disorder were excluded. All subjects scoring 20 or higher on the Dissociative Experiences Scale were interviewed with the Dissociative Disorders Interview Schedule. Then subjects with a diagnosis of multiple personality disorder and comparison subjects were interviewed by a clinician who was blind to all research data. RESULTS: A total of 299 subjects completed the Dissociative Experiences Scale and 80 received a structured diagnostic interview. Ten subjects (3.3%) had clinically confirmed multiple personality disorder. CONCLUSIONS: If these results are replicated and accepted, multiple personality disorder will become a serious consideration in the differential diagnosis of many psychiatric patients.

Adult↗