Search PubMed⌕ Search

Biomedical subjects

D Stewart

Publications and source records attributed to D Stewart.

At least 127 records · Page 7Linked to original sources
PubMed1999

Application of the Person-Environment-Occupation Model: a practical tool.

Occupational therapy focuses on complex dynamic relationships between people, occupations and environments. Therapists must clearly communicate their practices and how their practice influences outcomes. This paper explores applications of the Person-Environment-Occupation Model (Law et al., 1996) in occupational therapy practice, and delineates how this particular model helps therapists to conceptualize, plan, communicate and evaluate occupational performance interventions. Three case studies illustrate how the model can be used by occupational therapists to systematically approach analysis of occupational performance issues while considering the complexities of human functioning and experience. The ways in which the model facilitates communication within and outside occupational therapy are explained. The Person-Environment-Occupation Model is offered as a tool for therapists to use in client(s)-therapist alliances to enable clients to successfully engage in meaningful occupations in chosen environments.

Aged↗
PubMed1999

Methadone treatment practices and outcome for opiate addicts treated in drug clinics and in general practice: results from the National Treatment Outcome Research Study.

BACKGROUND: General practitioners (GPs) are increasingly urged to become more involved in the care and treatment of drug misusers. Little information is available about the effectiveness of treatments delivered in primary health care or specialist settings. The impact of treatment setting is investigated as part of the National Treatment Outcome Research Study (NTORS). This is the largest study of treatment outcome for drug misusers ever conducted in the United Kingdom (UK). AIM: This paper presents six-month treatment outcomes for patients who received community-based methadone treatment in either a specialist drug clinic or a general practice setting. METHOD: A prospective, multisite follow-up study of treatment outcome was conducted with 452 opiate addicts who had been given methadone treatment in primary health care and specialist clinic settings. Outcome data are presented for substance use behaviours, health, and crime. RESULTS: Improvements at follow-up were found among both the GP and the clinic-treated groups in drug-related problems, health, and social functioning. Problems at intake were broadly comparable among the clinic-based and the GP patients. Similar levels and types of improvement were found for both groups at six-month follow-up. CONCLUSIONS: Results demonstrate the feasibility of treating opiate addicts using methadone in primary health care settings, and show that treatment outcomes for such patients can be as satisfactory as for patients in specialist drug clinics. The GPs in our study are unrepresentative in their willingness to be actively involved with problem drug users; moreover, several services treated relatively large numbers of drug users. Issues surrounding the growth of 'GP specialists' are discussed.

Adolescent↗
PubMed1998

Expression of skeletal muscle-type voltage-gated Na+ channel in rat and human prostate cancer cell lines.

Previous electrophysiological work has demonstrated expression of a voltage-gated Na+ channel (VGSC) specifically in two highly metastatic prostatic epithelial tumour cell lines: MAT-LyLu (rat) and PC-3 (human). However, the identity of the channel(s) present was uncertain. The present study used a combination of molecular biological techniques to demonstrate that full-length skeletal muscle type 1 (SkM1) VGSC mRNA is present in the mRNA pool of the MAT-LyLu cell line. mRNA for this particular channel type was also expressed in the PC-3 cells. In situ hybridisation data suggested that the level and pattern of rSkM1 mRNA expression were different in the Dunning cells of markedly different metastatic potential. Interestingly, the same type of mRNA was also detected in the weakly metastatic counterparts of the cells: AT-2 (rat) and LNCaP (human).

Animals↗
PubMed1998

Impaired endothelin-1 release in tilt-induced syncope.

The neurohumoral events associated with neurocardiogenic syncope remain unclear. The simultaneous assessment of changes in endothelium-dependent and independent hormones and in autonomic balance in patients with tilt-induced syncope has been incompletely studied. Forty-six healthy subjects aged between 21 and 83 years (mean +/- SEM 47 +/- 3) underwent a 30-minute head-up tilt test at 60 degrees. Fourteen subjects (10 females and 4 male subjects) exhibited syncope at 16 +/- 2 minutes into the tilt. Hemodynamics were recorded every 5 minutes and blood samples for the measure of catecholamines, endothelin-1 (ET-1), and angiotensin-II (AT-II), were drawn at baseline, and 5, 10, 15, and 30 minutes into the tilt and immediately before syncope. Heart rate variability was analyzed by 5-minute segments during the test. Both catecholamines and ET-1 levels increased consistently in response to head-up tilt in subjects able to tolerate the test. Epinephrine increased to a greater extent before syncope. In contrast, ET-1 failed to increase at any time during the tilt and just before syncope. AT-II increased at 30 minutes into the tilt only in the control group. Finally, power in high-frequency bands decreased less in the group with syncope. Thus, compared with subjects able to tolerate a head-up tilt test, patients with syncope exhibit a greater increase in adrenomedullary activation, no significant increase in ET-1 levels, and a blunting in the decrease of vagal tone before syncope. The lack of increase in ET-1 during tilt may play a role in the inability to support orthostatic stress.

Adult↗
PubMed1998

Analysis of essential histidine residues of maize branching enzymes by chemical modification and site-directed mutagenesis.

Incubation of maize branching enzyme, mBEI and mBEII, with 100 microM diethylpyrocarbonate (DEPC) rapidly inactivated the enzymes. Treatment of the DEPC-inactivated enzymes with 100500 mM hydroxylamine restored the enzyme activities. Spectroscopic data indicated that the inactivation of BE with DEPC was the result of histidine modification. The addition of the substrate amylose or amylopectin retarded the enzyme inactivation by DEPC, suggesting that the histidine residues are important for substrate binding. In maize BEII, conserved histidine residues are in catalytic regions 1 (His320) and 4 (His508). His320 and His508 were individually replaced by Ala via site-directed mutagenesis to probe their role in catalysis. Expression of these mutants in E. coli showed a significant decrease of the activity and the mutant enzymes had Km values 10 times higher than the wild type. Therefore, residues His320 and His508 do play an important role in substrate binding.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1998

Interactions of mild hyperthermia, cisplatin and split dose irradiation in human ovarian carcinoma cells.

PURPOSE: Human ovarian cancer cells were evaluated to determine whether combination treatment with mild hyperthermia and cisplatin could inhibit repair of sublethal radiation damage. MATERIALS AND METHODS: Human ovarian carcinoma cell lines A2780S (parental line) and A2780CP (cisplatin resistant variant) were used in this study. Cisplatin at concentrations of 1 or 3 microg/ml was given concomitantly with 1 h of heating at 40 degrees C either immediately before or after irradiation. Survival was determined using a colony-forming assay. RESULTS: Neither mild hyperthermia nor cisplatin treatments alone affected sublethal damage repair. The combined treatment showed an effect in both cell lines and was treatment sequence-dependent. The effect was greater in the parental cell line. CONCLUSIONS: The data show that combined treatment of cisplatin and hyperthermia may have clinical efficacy at cisplatin concentrations and hyperthermia temperatures which by themselves have little to no effect.

Animals↗
PubMed1998

Factors influencing exercise performance in patients with left ventricular dysfunction. SOLVD Investigators. Studies of Left Ventricular Dysfunction.

BACKGROUND: The determinants of exercise performance are multifactorial and incompletely understood in patients with symptomatic left ventricular (LV) dysfunction, with much less information regarding asymptomatic LV dysfunction. This study assessed the hemodynamics and neurohormonal factors influencing exercise performance in patients with LV ejection fractions > or =0.35, both symptomatic and asymptomatic, enrolled in Studies of LV Dysfunction. METHODS AND RESULTS: We studied 103 patients enrolled prospectively in Studies of LV Dysfunction before randomized therapy; 38 were symptomatic and 65 had no or minimal symptoms. By using rest-exercise gated equilibrium radionuclide ventriculography and cuff blood pressure, we assessed the heart rate, LV and right ventricular (RV) volumes and ejection fractions, total peripheral resistance, the LV peak systolic pressure/end systolic volume ratio as an index of contractility, and plasma renin and norepinephrine at rest and during maximal graded supine bicycle ergometer exercise. Changes between rest and exercise were evaluated as indices of cardiovascular reserve. The cumulative workload ranged from 120 to 2,100 watt-min. At rest, the LV ejection fraction was 0.30 in asymptomatic patients and 0.25 in symptomatic patients, respectively (P < .0004). During exercise, asymptomatic patients had greater increases in heart rate, systolic blood pressure, LV ejection fraction, and cardiac output than symptomatic patients (P > or = .05). Combining all patients, the strongest univariate correlates of exercise workload were the ability to increase heart rate (r = 0.70), the pressure/volume ratio (r = 0.63), and systolic blood pressure (r = 0.55), and to decrease the total peripheral resistance (r = -0.47) with moderate correlations for the ability to increase LV and RV ejection fractions (r = 0.33 and 0.35, respectively) (P < .0008). By multivariate analysis, workload was modeled best by the changes in four factors: heart rate, systolic blood pressure, and the LV and RV ejection fractions (R2 = 0.54, P < .001). CONCLUSION: Exercise performance and its hemodynamics differed in patients with symptomatic and asymptomatic LV dysfunction. Rather than features at rest, the reserve capacities for increasing heart rate, systolic blood pressure, and the LV and RV ejection fractions were the predominant cardiac mechanisms related to greater exercise performance.

Adult↗
PubMed1998

Phase I clinical study of didemnin B. A National Cancer Institute of Canada Clinical Trials Group study.

Didemnin B (NSC-325319), a new depsipeptide isolated from a Caribbean tunicate, has been evaluated in a clinical phase I study. The drug was administered in a schedule of a 4 weekly intravenous injection in a six-weeks cycle. Fifty-three patients received 71 evaluable cycles in an escalated dose ranging from 0.4 mg/m2/week to 2.5 mg/m2/week. No hematological toxicity was demonstrated at any dose level. Without prophylactic antiemetics nausea and vomiting was dose limiting at 1.2 mg/m2/week. Due to the use of Cremophor EL as a solvent, hypersensitivity reactions occurred in 9 patients. These reactions occurred following prior exposure to the drug and were commonly seen at the 3rd dose. They were not dose related but became more frequent at 1.5 mg/m2/week necessitating prophylactic treatment with H and H2 receptor blocking agents. Non-hematological toxicities included mild diarrhea, mucositis, anorexia, headaches, and local phlebitis. The dose- limiting toxicity was generalized weakness which became severe and disabling in 3 of 6 patients treated at 2.5 mg/m2/week. No objective responses were documented in 39 patients with evaluable disease. The recommended dose for phase II studies was 2.3 mg/m2/week x 4 in a 6-weeks cycle given with prophylactic antiemetics and H1 and H2 receptor blocking agents.

Adult↗
PubMed1998

The Maudsley Addiction Profile (MAP): a brief instrument for assessing treatment outcome.

AIM: To develop a brief, multi-dimensional instrument for assessing treatment outcome for people with drug and/or alcohol problems. The Maudsley Addiction Profile (MAP) is the first instrument to be developed in the United Kingdom for this purpose. DESIGN: Field testing with quota-recruitment of problem drug users and problem alcohol users in treatment with researcher and clinician-administered test-retest interviews. SETTING: Two community and two inpatient services at the Bethlem Royal and Maudsley Hospital, London. PARTICIPANTS: Subjects (160 drug users and 80 alcohol users) interviewed by eight interviews (four researchers and four clinicians), each of whom interviewed 30 subjects on two occasions. MEASURES: Sixty items across substance use, health risk, physical/psychological health and personal/social functioning domains. FINDINGS: Average completion time of the MAP was 12 minutes. The questionnaire was acceptable to a majority of subjects and performed well with both researcher and clinician interviewers. Internal reliability and feasible concurrent validity assessments of the scales and items were highly satisfactory. Test-retest reliability was good, average intraclass correlation coefficients across eight substances were 0.94 and 0.81 across health risk, health problems, relationship conflict, employment and crime measures. CONCLUSIONS: The MAP can serve as a core research instrument with additional outcome measures added as required. The collection of a set of reliable quantitative measures of problems among drug and alcohol users by research or treatment personnel for outcome evaluation purposes need not be time-consuming.

Adult↗
PubMed1998

Characterization of an AGAMOUS homologue from the conifer black spruce (Picea mariana) that produces floral homeotic conversions when expressed in Arabidopsis.

Advances in elucidating the molecular processes controlling flower initiation and development have provided unique opportunities to investigate the developmental genetics of non-flowering plants. In addition to providing insights into the evolutionary aspects of seed plants, identification of genes regulating reproductive organ development in gymnosperms could help determine the level of homology with current models of flower induction and floral organ identity. Based upon this, we have searched for putative developmental regulators in conifers with amino acid sequence homology to MADS-box genes. PCR cloning using degenerate primers targeted to the MADS-box domain revealed the presence of over 27 MADS-box genes within black spruce (Picea mariana), including several with extensive homology to either AP1 or AGAMOUS, both known to regulate flower development in Arabidopsis. This indicates that like angiosperms, conifers contain a large and diverse MADS-box gene family that probably includes regulators of reproductive organ development. Confirmation of this was provided by the characterization of an AGAMOUS-like cDNA clone called SAG1, whose conservation of intron position and tissue-specific expression within reproductive organs indicate that it is a homologue of AGAMOUS. Functional homology with AGAMOUS was demonstrated by the ability of SAG1 to produce homeotic conversions of sepals to carpels and petals to stamens when ectopically expressed in transgenic Arabidopsis. This suggests that some of the genetic pathways controlling flower and cone development are homologous, and antedate the 300-million-year-old divergence of angiosperms and gymnosperms.

AGAMOUS Protein, Arabidopsis↗
PubMed1998

What makes women tired? A community sample.

We aimed to determine the major health concerns or problems of women and their personal attributions for the causes of their primary health concerns. We used a survey of women from the Toronto area attending a women's health symposium. Completed questionnaires were returned by 153 (85%) of 180 women attendees. Persistent fatigue was the primary and most commonly cited health concern. Fatigue was ranked first by 42 (27.5%) women and among the top 10 concerns by 123 (80.4%) women. Women attributed their fatigue to a combination of home and outside work (63.4%), poor sleep (38.2%), lack of time for self (34.1%), lack of exercise (32.5%), financial worries (28.5%), relationship problems (22.0%), emotional causes (17.9%), care of ill family members (13.8%), lack of social or individual support (9.8%), poor physical health (8.9%), work in home or child care (3.3%), or gender bias/harassment (2.4%). Our subjects, women from the community, overwhelmingly endorsed social determinants as the cause of their persistent fatigue. Although depression and anxiety form the most robust associations with persistent fatigue in primary care and community studies, women in this sample ranked these factors in seventh place in their attributions. Similarly, although physicians often assume physical causes for fatigue, women rank physical health low in their own attributions. Given the high prevalence of fatigue in women and its impact on quality of life, more attention needs to be given to the social, systemic, and personal factors that women feel contribute to their fatigue to develop more effective interventions.

Adult↗
PubMed1998

Cardiac rehabilitation: gender differences in factors influencing participation.

This study investigates gender differences in the barriers and incentives that are most influential in the coronary patient's decision to participate in cardiac rehabilitation programs (CRPs) and suggests strategies to counter these barriers. Patient surveys were administered to consecutive English-speaking attenders and referred nonattenders to a cardiac rehabilitation center at a university healthcare system in Toronto, Canada. A survey questionnaire, constructed from a literature review and advice from key informants, examined potential factors affecting decisions to engage in CRPs. One hundred twenty-nine attenders at a CRP and 61 referred nonattenders completed the questionnaire. Physician recommendation was reported to be the most important factor influencing both women's and men's decisions to participate in CRPs, followed by encouragement from family members. For women who had attended CRP, encouragement from their adult children was significantly more influential than it was for men. Attention to health promotion was also a significantly more powerful motivator for women than it was for men. For CRP nonattenders, concomitant illness, transportation problems, and inconvenient timing of the program were stated to be the three most important barriers to CRP participation in both sexes, although women rated concomitant illness as a significantly more powerful barrier than did men. The decision to participate in CRPs involves several factors, some of which are different or more important for women. As physician recommendations continue to be the single most important factor in motivating both men and women to attend, strengthened and increased physician endorsement will likely encourage higher levels of participation in CRPs. For women, permission should be sought to discuss the advantages of CRPs with adult children who are apparently influential in the decision. As women nonattenders are more concerned than men about the effects of concomitant illnesses, reassurance should be provided about customized programs and exercise targets that consider the needs and limitations of individuals with other health conditions.

Aged↗
PubMed1998

The fate of paternal mitochondrial DNA in developing female mussels, Mytilus edulis: implications for the mechanism of doubly uniparental inheritance of mitochondrial DNA.

Species of the marine mussel family Mytilidae have two types of mitochondrial DNA: one that is transmitted from the mother to both female and male offspring (the F type) and one that is transmitted from the father to sons only (the M type). By using pair matings that produce only female offspring or a mixture of female and male offspring and a pair of oligonucleotide primers that amplify part of the COIII gene of the M but not the F mitochondrial genome, we demonstrate that both male and female embryos receive M mtDNA through the sperm and that within 24 hr after fertilization the M mtDNA is eliminated or is drastically reduced in female embryos but maintained in male embryos. These observations are important for understanding the relationship between mtDNA transmission and sex determination in species with doubly uniparental inheritance of mitochondrial DNA.

Age Factors↗
PubMed1998

Constructing simultaneous communication: the contributions of natural sign language.

This article examines simultaneous communication (SC) by analyzing the changes in productions of teachers who underwent a program specifically designed to address improvements in the signed modality by working with both English-based signing and American Sign Language (ASL). Based on theoretical concepts found in bilingualism, language contact situations, and conversational analysis, we focus on the process of constructing utterances by examining the teachers' spontaneous repair sequences as evidence of an active productive system. Two teachers received special instruction in SC that included both ASL and English-based signing systems as separate but equal systems. Videotapes of their use of SC, collected over four years, were analyzed for sign/speech ratio and repair sequences. Repairs were classified as repetitions, replacements, or synchronization. We found that the sign/speech ratio of both teachers increased over time. Examination of repair sequences showed that repetitions tended to occur in speech with the sign channel more completely encoded in the repair. Changes in speech tended to be accompanied by changes in sign. Errors in synchrony were relatively rare. We conclude that the simultaneous communication of both teachers was speech-driven, but error detection was largely sign-driven. The greater the automaticity of both languages, the more attention could be devoted to monitoring the coordination of the two modalities. The amount and quality of monitoring that actually occurred, however, were subject to individual differences.

Journal Article↗
PubMed1998

Economic burden of drug dependency. Social costs incurred by drug users at intake to the National Treatment Outcome Research Study.

BACKGROUND: The use of illegal drugs is seen as a major social problem. The social costs can be high. METHODS: Self-report data from interviews at intake to the National Treatment Outcome Research Study (NTORS) for 1075 drug users and cost data from various sources were used to estimate criminal behaviour and health and addiction service costs for a 12-month period. Multivariate statistical analysis was used to analyse cost variations. RESULTS: Total costs for one year for the drug users amounted to over 12 million Pounds, the majority attributable to self-reported criminal behaviour. Social costs were positively related to a variety of factors including instability in living circumstances, amount of heroin used and whether or not drugs were taken intravenously. CONCLUSIONS: The study clearly demonstrates the economic and social burden associated with heavy drug users and highlights the need for further investigations into the costs and benefits of policies that can reduce these social costs.

Age Factors↗
PubMed1998

Substance use, health and social problems of service users at 54 drug treatment agencies. Intake data from the National Treatment Outcome Research Study.

BACKGROUND: The National Treatment Outcome Research Study (NTORS) is the first large-scale, prospective, multi-site treatment outcome study of drug users in the UK. METHOD: Substance use, health and social problems of 1075 service users were assessed at intake to 54 agencies chosen to be representative of the main national drug treatment modalities. RESULTS: Heroin dependence was the most frequently reported problem often with poly-drug and alcohol problems. Most service users injected drugs and a quarter of the injectors shared injecting equipment. Poly-drug use and heavy drinking were more common among service users admitted to residential treatments. High criminality rates were reported. Psychological and physical health problems were common and many service users had prior contact with psychiatric and medical services. CONCLUSIONS: The range and severity of problems adversely affect individual users, their families, and present a challenge to addiction treatment services. These problems create costs for the health care, social service and criminal justice system responses.

Adolescent↗