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Biomedical subjects

S J Elliott

Publications and source records attributed to S J Elliott.

67 records · Page 4Linked to original sources
PubMed1991

Production of type 1 fimbriae by Escherichia coli HB101.

Escherichia coli HB101 is frequently used as a host in the cloning of bacterial virulence genes because of its reported lack of virulence determinants such as fimbriae, adhesins and haemagglutinins. However, passage of HB101 in standing broth culture rapidly induced the production of fimbriae which mediated adhesion to HEp-2 cells and mannose-sensitive haemagglutination of human and guinea-pig erythrocytes. Fimbrial serology, morphology and pilin molecular mass of 18 kDa were consistent with those of type 1 fimbriae.

Animals↗
PubMed1991

Oxidative stress inhibits bradykinin-stimulated 45Ca2+ flux in pulmonary vascular endothelial cells.

The effects of oxidant stress and altered glutathione reductase activity on agonist-induced flux of Ca2+ were studied in cultured calf pulmonary artery endothelial cells using radioisotopic 45Ca2+. Bradykinin-stimulated uptake of 45Ca2+ was determined after cells were incubated with the membrane-permeant oxidant t-butylhydroperoxide (0.4 mM) for various durations. t-Butylhydroperoxide increased uptake of 45Ca2+ under basal conditions and significantly decreased bradykinin-stimulated uptake in a time-dependent manner through incubation periods of 2 h. Preincubation of cells with 1,3-bis(chloroethyl)-1-nitrosourea markedly reduced bradykinin-stimulated uptake in cells subsequently treated with t-butylhydroperoxide. Bradykinin-stimulated efflux of 45Ca2+ and 86Rb+ was examined in control and oxidant-stressed endothelial cells. t-Butylhydroperoxide initially decreased bradykinin-stimulated efflux of 45Ca2+ but had no effect on 86Rb+ efflux. After more prolonged incubation with the oxidant, stimulated 45Ca2+ efflux was further inhibited, and basal efflux of 86Rb+ was increased to a rate similar to that observed with bradykinin stimulation. Elevated basal 86Rb+ efflux was blocked by tetrabutylammonium chloride, a selective inhibitor of Ca2(+)-dependent K+ channels in endothelial cells. These findings, together with our previously described results using fura-2, suggest that oxidant stress initially inhibits bradykinin-stimulated Ca2+ influx and later inhibits stimulated Ca2+ efflux. Finally, cytosolic free Ca2+ concentration becomes persistently elevated and is associated with elevated basal efflux of K+ via the Ca2(+)-dependent K+ channel.

Animals↗
PubMed1990

Carmustine augments the effects of tert-butyl hydroperoxide on calcium signaling in cultured pulmonary artery endothelial cells.

The effects of oxidant stress and inhibition of glutathione reductase on the bradykinin-stimulated changes in cytosolic free Ca2+ concentration ([Ca2+]i) of calf pulmonary artery endothelial cells were determined using the intracellular fluorescent probe, fura-2. Changes in [Ca2+]i upon stimulation with bradykinin were measured after incubation of cells with the chemical oxidant tert-butyl hydroperoxide (0.4 mM) for various times. After 60 min, bradykinin-stimulated Ca2+ influx was significantly decreased. With more prolonged incubations with the peroxide, bradykinin had little effect on cytosolic calcium concentration. Preincubation of cells with the glutathione reductase inhibitor, carmustine, led to elevated basal [Ca2+]i, yet the cells remained responsive to bradykinin. However, incubation of carmustine-treated cells with tert-butyl hydroperoxide for 30 min dramatically reduced both bradykinin-stimulated release of Ca2+ from internal stores and influx of Ca2+ from the extracellular space. These results suggest that inhibition of glutathione reductase alters cytosolic Ca2+ homeostasis and enhances the effects of oxidative stress on signal transduction in vascular endothelial cells.

Animals↗
PubMed1990

Housing satisfaction, preference and need among the chronically mentally disabled in Hamilton, Ontario.

This paper examines housing satisfaction, preference and need among a sample of the CMD in Hamilton, Ontario. The research goes beyond simply documenting the gap in housing supply by examining issues of housing quality as expressed by clients themselves. Survey data were obtained in two rounds of interviews from 66 clients attached to three aftercare programmes. Various indicators were consistent in showing a relatively high level of satisfaction with the current living situation. At the same time, clients reported major housing difficulties due to lack of appropriate and affordable accommodation, unacceptable conditions and financial constraints. Housing satisfaction was a significant correlate of scores of coping indices. There was considerable variability in satisfaction within groups of the sample defined in terms of type of housing, location and living arrangement. Data on preferences and expressed needs correspond quite closely with normative prescriptions for a continuum of housing options ranging from restricted congregate care to autonomous individual living situations. These findings underline the heterogeneity of the CMD and their needs.

Adaptation, Psychological↗
PubMed1990

Parameter interpolation in speech synthesis.

A comparison has been made of the transition properties of six types of speech synthesizer parameters: serial resonance, prediction coefficients, reflection coefficients, area functions, parallel resonance, and, finally, a simple set of articulatory parameters. The first four synthesizers are formally equivalent and can be made to produce identical steady-state sounds (targets). The last two involve approximations, but achieve similar targets. Formant paths between targets will differ according to the parameter type used during interpolation. Each type was tested on nonsense words spanning a wide range of parameter values. Linear interpolation of synthesizer parameters was used to determine a path between target values. The resultant data were then converted to formant values and plotted as a spectrographic (frequency versus time) representation. Small differences in formant frequency (versus linear transitions of formant frequency and bandwidth) were common, and some quite large differences in formant bandwidths were observed in certain cases.

Communication Devices for People with Disabilities↗
PubMed1989

Effect of t-butyl-hydroperoxide on bradykinin-stimulated changes in cytosolic calcium in vascular endothelial cells.

The effect of oxidant stress on agonist-induced changes in endothelial cell cytosolic free Ca2+ (Ca2+i) was measured using the fluorescent probe, fura-2. Cultured vascular endothelial cells were loaded with fura-2 via the acetoxymethyl ester form, fura-2/AM, before incubation with t-butyl-hydroperoxide (0.4 mM). Bradykinin-stimulated changes in (Ca2+i) were measured in cells exposed to the hydroperoxide for 0, 30, 60, 120, and 180 min. Incubation of cells with the oxidant initially (within 30 min) diminished the peak rise in (Ca2+i) that occurs after stimulation with bradykinin. Experiments conducted with cells in a Ca2+-free buffer indicated that t-butyl-hydroperoxide inhibited bradykinin-stimulated Ca2+ influx from the extracellular space and had little effect on agonist-induced release of Ca2+ from internal stores. At the later incubation periods (greater than 60 min), basal (Ca2+i) progressively rose and the peak response to bradykinin progressively decreased. After 180 min, the cells appeared unable to maintain steady-state with respect to Ca2+ flux. These alterations in Ca2+ homeostasis occurred before detectable changes in the ability of the cells to exclude trypan blue. These results suggest that oxidant stress alters the change in Ca2+i of vascular endothelial cells following stimulation with vasoactive agents.

Animals↗
PubMed1985

Hematuria after renal allograft biopsy: treatment with aminocaproic acid.

Aminocaproic acid (EACA) was used in 2 patients with cadaveric renal allografts because gross hematuria developed after percutaneous renal biopsies. Marked improvement was noted within twelve hours with no recurrence after discontinuation of EACA. EACA was effective in moderate renal failure.

Adolescent↗
PubMed1985

Clinical presentation and management of Pseudomonas osteomyelitis.

To determine the incidence and clinical characteristics of Pseudomonas aeruginosa osteomyelitis in children, the records of 144 hospitalized patients under 19 years of age were reviewed; 104 fulfilled the study criteria for the diagnosis of acute or chronic osteomyelitis. Pseudomonas aeruginosa was recovered from 10.6 percent of the children and was the second most common pathogen isolated. In comparison to children with staphylococcal infections, patients with pseudomonal osteomyelitis were significantly older, gave an antecedent history of penetrating trauma, and lacked clinical and laboratory evidence of systemic illness. The data collected in this study suggest that osteomyelitis due to Pseudomonas aeruginosa is a distinct entity with clinical features differing from those of Staphylococcus aureus. Management should be directed at adequate surgical debridement followed by 10 to 21 days of antimicrobial therapy.

Adolescent↗
PubMedDate not supplied

Restructuring public health in Ontario: implications for heart health promotion.

Community-based heart health promotion is viewed as an effective means of reducing cardiovascular disease risk. Although public health agencies have a central role in the implementation and dissemination of heart health programmes, their effectiveness is being challenged by major structural changes to Provincial public health systems across Canada, although the impacts of the changes have received relatively little attention in the research literature. As part of the Canadian Heart Health Initiative--Ontario Project (CHHIOP), this study used a qualitative approach to address the perceived implications of these changes to Ontario's public health system for heart health promotion. Interviews (n = 38) were conducted in eight public health units with staff most familiar with managing and/or delivering heart health activities. The results are mixed; that is, while many see the future of heart health promotion programming in Ontario as being at risk, others see recent changes as a step forward toward their institutionalization, particularly in light of recent funding decisions made by the Ministry of Health's Health Promotion Branch.

Female↗
PubMedDate not supplied

Partnering in and for heart health promotion: findings from a survey of community organizations.

This paper presents the results of a survey conducted with representatives (n = 283) of community health agencies linked to heart health activity in Ontario in order to: 1) describe their levels of involvement in heart health promotion, 2) describe the nature and extent of partnering undertaken in the context of community-based heart health promotion, and 3) assess the extent to which community development approaches vis-à-vis partnering are being employed in Ontario heart health promotion. The survey included a series of questions regarding level of agency involvement in heart health promotion activities organized around four areas: tobacco, nutrition, physical activity and general heart health. Respondents were also asked to report the nature and extent of partnering that took place. Results indicate that levels of involvement varied significantly across activity area and by organization, although every agency type reported some level of involvement in each of the four activity areas. Overall, agencies surveyed continue to employ traditional settings (i.e., schools and community) as well as strategies (i.e., public education) but report a substantial amount of partnering and collaboration when undertaking community-based heart health promotion activities.

Cardiovascular Diseases↗
PubMedDate not supplied

An ecologic analysis of psychosocial stress and heart disease in British Columbia.

Cardiovascular disease is the leading cause of death in Canada. However, much heart disease incidence cannot be explained by known risk factors, and evidence points to the potential role played by the psychosocial environment. This study involves an ecologic analysis exploring the relationships between psychosocial stress and ischaemic heart disease (IHD) in British Columbia. First, data from the Canada Health Promotion Survey correlated stress indicators (i.e., education, marital status) with self-reported stress levels. Results showed gender differences in stress. Stage II consisted of a multivariate analysis of ischaemic heart disease mortality in B.C. Results indicate a strong association between heart disease outcomes and educational background for both males and females. Findings of this study support a link between IHD and psychosocial factors. The results of the multiple regression must be interpreted with caution, given the use of an ecologic analysis. Additional research at the individual level is needed to fully understand these relationships.

Adult↗