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Biomedical subjects

S Wheeler

Publications and source records attributed to S Wheeler.

At least 37 records · Page 2Linked to original sources
PubMed1996

Benefits of the placebo effect in the therapeutic relationship.

This paper starts by defining placebos, and describes several placebo effects observed in orthodox medicine. The authors argue that the concept of the placebo effect should not be confined to treatment and medicine alone, but should be extended to the therapeutic relationship itself. They maintain that the interpersonal skills practiced by the complementary therapist are a major factor in producing positive health outcomes. Furthermore, the personality, presentation, and demeanour of the complementary therapist are thought to play a vital part in the promotion of clients' psychological well-being. Other benefits of the placebo effect are discussed, including positive behaviour reinforcement resulting in the client's desire to return to the therapist for further consultation and treatment. The paper concludes by offering several ways in which the placebo effect can be established within the boundaries of the therapeutic relationship.

Holistic Nursing↗
PubMed1996

Lamivudine in children with human immunodeficiency virus infection: a phase I/II study. The National Cancer Institute Pediatric Branch-Human Immunodeficiency Virus Working Group.

The safety, tolerability, pharmacokinetic profile, and preliminary activity of lamivudine (2'-deoxy-3'-thiacytidine), a novel cytidine nucleoside analogue with antiretroviral activity, in human immunodeficiency virus (HIV)-infected children beyond the neonatal period were studied. Ninety children received dosages of 1-20 mg/kg/day. Pharmacokinetic evaluation demonstrated serum and cerebrospinal fluid concentrations that increased proportionally to dose. As of January 1994, 11 children had been withdrawn from study for disease progression and 10 because of possible lamivudine-related toxicity, and 6 had died. CD4 and CD8 cell counts remained stable over 24 weeks in therapy-naive children and decrease slightly in previously treated children. Quantitative immune complex-dissociated p24 antigen and HIV RNA were decreased significantly at 12 and 24 weeks. In vitro resistance to lamivudine was documented in sequential virus isolates from some patients by 12 weeks. Lamivudine was well-tolerated and exhibited virologic activity in children, although future use in children is likely to be in combination antiretroviral regimens.

Adolescent↗
PubMed1996

Cocaine-induced microvascular vasoconstriction but differential systemic haemodynamic responses in Yucatan versus Yorkshire varieties of swine.

1. Systemic and coronary haemodynamics were measured in 6 Yorkshire swine and 6 Yucatan miniature swine under isoflurane anaesthesia to investigate the influence of cocaine following its intravenous administration at 1, 3 and 7 mg kg-1. 2. Cocaine in Yorkshire swine decreased mean arterial pressure and rate pressure product (systolic pressure x heart rate), suggesting a cardiac depressant effect, whereas cocaine in Yucatan miniature swine increased these parameters, consistent with a hyperadrenergic state. 3. Cocaine in both Yorkshire swine and Yucatan miniature swine decreased coronary blood flow and coronary flow reserve, and increased coronary vascular resistance. 4. A modest generalized epicardial coronary artery constriction was observed by angiography, without evidence of focal spasm. 5. Our results confirm a marked vasoconstrictor effect of cocaine on the coronary arterial circulation, predominantly distal to the epicardial coronary arteries, but also indicate important differences in the systemic cardiovascular responses to the drug between two closely related strains of animals within the same species. Due to the similarities between the swine and human coronary arterial vasculature, we suggest that vasoconstriction in the coronary microcirculation may produce cardiac toxicity in man.

Angiocardiography↗
PubMed1996

Resistance to (-)-2',3'-dideoxy-3'-thiacytidine (3TC) in HIV-1 isolated from paediatric patients.

We conducted detailed virological evaluations of 16 HIV-1-infected paediatric patients treated with 3TC (lamivudine) monotherapy. High-level phenotypic resistance against this compound (up to 2,500-fold) was seen in virtually all cases, usually within 8-12 weeks of initiation of therapy. This was concomitant with the appearance of the M184V mutation in viral reverse transcriptase, previously shown to be responsiblefor such resistance. Viral burden fell in virtually all cases after commencement of therapy, and remained below baseline in each instance studied, despite a rebound effect and the appearance of drug resistance. Viral isolates from some patients underwent a switch from a non-syncytium-inducing (NSI) to a syncytium-inducing (SI) phenotype during the course of the study, although no relationship was apparent between dose of drug employed, time to development of drug resistance or time of appearance of SI phenotype.

Anti-HIV Agents↗
PubMed1995

Fibrin degradation product (FnDP) assays: analysis of standardization issues and target antigens in plasma.

The in vivo formation of fibrin and its subsequent secondary fibrinolytic digestion yields a variety of crosslinked fibrin degradation products (XL/FnDP). One of these is known as D-dimer and a variety of ELISA-type commercial kits using monoclonal antibodies to D-dimer have been developed. We have investigated the possibility of establishing a standard such that these various kits might indicate the same levels of D-dimer in the same samples. We have concluded that because it seems that each individual monoclonal antibody to D-dimer targets a unique and distinct epitope in the FnDP fraction the notion of introducing a standard D-dimer which will respond uniformly to each D-dimer monoclonal antibody is not feasible. Using various monoclonal and polyclonal antibodies in conjunction with gel exclusion chromatography we have examined human plasma derived from patients with disseminated intravascular coagulation (DIC) which contained high levels of fibrin degradation products (FnDP). The data suggested that the FnDP fraction in plasma contained mostly high molecular weight (> 2 x 10(6) daltons) crosslinked fragments which contain high levels of fibrinopeptide A. Many of these crosslinked fragments crossreact with antibodies to D-dimer because they each contain D-dimer as a structural component. On the basis of this data, a novel sequence of events is proposed which may occur during the aggregation of fibrin in vivo.

Antibodies, Monoclonal↗
PubMed1995

Ethical issues in qualitative nursing research.

This article is concerned with ethical issues that have to be considered when undertaking qualitative research. Some of the issues--such as informed consent, the dignity and privacy of the research subjects, voluntary participation and protection from harm--are the same as in other types of research and have their basis in moral and ethical principles. Qualitative research, however, generates specific ethical problems because of the close relationship that researchers form with participants. Qualitative research with patients is especially difficult because of their vulnerability and lack of power in the clinical situation. Therefore the potential conflict between the dual role of the nurse--the professional and the research roles--has to be solved. Researchers also learn how to cope with the tension of subjective and objective elements of the research. Nurses who attempt qualitative research have to consider a variety of complex ethical issues, which are addressed in this paper.

Behavioral Research↗
PubMed1994

Use of a rapid assay of subforms of creatine kinase MB to diagnose or rule out acute myocardial infarction.

BACKGROUND: Ruling out myocardial infarction in patients coming to the emergency room with chest pain is hindered by the lack of a specific early diagnostic marker. Less than 30 percent of patients admitted to coronary care units have infarction, resulting in substantial unnecessary expenditures. We developed a rapid assay of the subforms of creatine kinase MB (CK-MB) and prospectively analyzed its sensitivity and specificity in diagnosing myocardial infarction in the first six hours after the onset of chest pain. METHODS: In 1110 consecutive patients who came to the emergency room with chest pain, blood samples were collected every 30 to 60 minutes until at least 6 hours after the onset of symptoms; in patients who were then admitted to the hospital, samples were collected every 4 hours for up to 48 hours. The samples were analyzed for CK-MB subforms, and the diagnosis of myocardial infarction was confirmed by conventional CK-MB analysis. RESULTS: Of the 1110 patients evaluated, 121 had myocardial infarction. The sensitivity of the assay of CK-MB subforms to detect myocardial infarction in the first six hours after the onset of symptoms was 95.7 per cent, as compared with only 48 percent for the conventional CK-MB assay; the specificity was 93.9 percent among patients hospitalized without myocardial infarction and 96.2 percent among those sent home. Among the patients with myocardial infarction, definitive results of the subform assay were available a mean (+/- SD) of 1.22 +/- 1.17 hours after their arrival in the emergency room. CONCLUSIONS: The assay of CK-MB subforms reliably detected myocardial infarction within the first six hours after the onset of symptoms, and its use could reduce admission to the coronary care unit by 50 to 70 percent, thereby reducing costs.

Biomarkers↗
PubMed1994

A prospective, randomized trial of gauze and two polyurethane dressings for site care of pulmonary artery catheters: implications for catheter management.

OBJECTIVES: To compare the safety of a conventional polyurethane transparent dressing and a novel highly permeable polyurethane dressing, as compared with standard gauze and tape, as site dressings for pulmonary artery catheters; and to rigorously determine the sources of bloodstream infections deriving from these catheters. DESIGN: Prospective, randomized, clinical trial. SETTING: General adult intensive care units (ICUs) in a university hospital. PATIENTS: A total of 442 adult patients with pulmonary artery catheters were studied. Two thirds of the catheters had been inserted in the operating room and one third had been inserted in an ICU. INTERVENTIONS: Patients were randomized at the time of pulmonary artery catheter insertion to have one of three dressing regimens: a) sterile gauze and tape (control), replaced every 2 days; b) a conventional polyurethane dressing, replaced every 5 days; or c) a highly permeable polyurethane dressing, also replaced every 5 days. MEASUREMENTS AND MAIN RESULTS: The origin of each catheter-associated bloodstream infection was sought by quantitatively culturing the skin of the insertion site and all potential sources on the catheter, including the hub and infusate from each lumen of the introducer sheath and the pulmonary artery catheter, and intravascular segments of the introducer sheath and pulmonary artery catheter. Bloodstream infection was confirmed by demonstrating concordance between isolates from the device and blood cultures by pulsed-field electrophoresis of genomic DNA, digested with low-frequency-cleavage, restriction endonucleases. One hundred thirty catheters were randomized to be dressed with sterile gauze and tape (control), 127 with the conventional polyurethane dressing, and 185 with the highly permeable polyurethane dressing. Patients and catheters in the three dressing groups were very comparable. Ninety-six (21.7%) of the 442 catheters studied showed colonization of the introducer sheath or the pulmonary artery catheter, and five (1.1%) catheters caused bloodstream infection. Catheter-related bloodstream infections were associated with concordant cutaneous colonization of the insertion site (n = 2), a contaminated catheter hub or infusate (n = 3), contamination of the extravascular segment of a repositioned catheter beneath the external protective plastic sleeve (n = 1), or hematogenous colonization of the catheter (n = 1). All pulmonary artery catheter-related bloodstream infections occurred with catheters (introducers) in place for > or = 5 days (p < .001). Cutaneous colonization under the dressing at catheter removal was lowest with gauze (10(1.3) colony-forming units), intermediate with the new highly permeable polyurethane dressing (10(1.8) colony-forming units; p < .01), and highest with the conventional polyurethane dressing (10(2.0) colony-forming units; p < .001). There were no significant differences in catheter colonization (20.0 to 25.2 cases per 100 catheters) or catheter-related bloodstream infection (0.8 to 1.6 cases per 100 catheters) between the three groups. CONCLUSIONS: The incidence of pulmonary artery catheter-related bloodstream infection has decreased over the past 5 yrs. Pulmonary artery catheter-related bloodstream infections originate from multiple sources, indicating that measures to prevent bacteremic infections of these devices must focus both on reducing cutaneous colonization at the insertion site and averting contamination of infusate and catheter hubs. Efforts should be made to limit the duration of catheterization with pulmonary artery catheters (including the introducer) to no longer than 4 days. The polyurethane dressings studied appear to be safe for use with pulmonary artery catheters and may be left on for up to 5 days between dressing changes.

Aged↗
PubMed1993

Waiting for coronary revascularization in Toronto: 2 years' experience with a regional referral office.

OBJECTIVES: To determine the frequency of major adverse events among patients awaiting coronary revascularization; to assess the match between referring physicians' estimates of urgency, a computer-generated multifactorial urgency rating score and actual waiting times; to determine the changes in waiting times as capacity for bypass surgery increased; and to evaluate the influence of choice of procedure or operator on waiting times. DESIGN: Consecutive case series. SETTING: Greater Toronto region. SUBJECTS: All 571 patients referred to an organized referral office by cardiologists at hospitals without on-site revascularization facilities between Jan. 3, 1989, and June 30, 1991. MAIN OUTCOME MEASURES: Preoperative fatal or nonfatal myocardial infarction; proportions of patients waiting longer than the maximum period recommended for their urgency rating; mean waiting times for various subgroups; and correlations among referring physicians' urgency ratings, computer-generated multifactorial urgency scores and waiting times. RESULTS: Of the 496 patients accepted for a procedure 5 had fatal cardiac events and 3 nonfatal myocardial infarction. Events occurred three times more often in patients with left mainstem disease than in those in other anatomic categories (relative risk [RR] 3.05, 95% confidence interval [CI] 1.48 to 6.27, p = 0.03). Both the computer-generated scores and the referring physicians' scores were correlated with the actual waiting time (r = 0.46 and 0.57 respectively). Waiting times and the proportion of patients with excessive waiting times fell during the study period (p < 0.0001). However, urgent cases were much less likely to be done "on time" than those with a recommended waiting time of more than 2 weeks (RR 0.16, 95% CI 0.11 to 0.25, p < 0.0001). The mean wait for coronary artery bypass grafting (CABG) was 22.73 days if the referral office was allowed to find a surgeon or interventional cardiologist and 35.31 days if one was requested (p = 0.002 after adjustment for urgency scores). CONCLUSIONS: Death of a patient on the waiting list is uncommon in an organized referral system. Patients with left main-stem disease are at higher risk of death than those in other anatomic categories. There were significant correlations between referring physicians' ratings of urgency, multifactorial urgency scores and actual waiting times. Expansion of capacity for CABG led to shorter waiting times, but patients with unstable symptoms continued to wait longer than recommended. Requests for a specific surgeon caused significantly longer delays.

Aged↗
PubMed1993

Queueing for coronary surgery during severe supply-demand mismatch in a Canadian referral centre: a case study of implicit rationing.

Queues for in-patient surgery are commonplace in universal health care systems. Clinicians and hospitals usually manage these waiting lists with informal criteria for determining patient priority--a form of implicit rationing. To understand the workings of implicit rationing by queue, we took advantage of a natural experiment in the Canadian province of Ontario. Unprecedentedly severe supply-demand mismatch led to long waiting lists for coronary surgery [CABS] in Ontario during 1987-88. The crisis was resolved by increased funding and widespread adoption of a multifactorial clinical index for patient priority that was developed by an expert panel in 1989. Thus, we audited randomly chosen charts of patients who underwent coronary angiography at four Toronto hospitals during the crisis period, and calculated urgency scores for each case based on the multifactorial index. From 413 charts, 193 eligible patients were identified who proceeded to CABS. Waiting times did correlate with urgency ratings (r = 0.42, P < 0.0001). However, mean wait from catheterization to CABS varied among hospitals by as much as 8 weeks (P < 0.0001 after controlling for urgency scores). At the hospital with shortest queues, waiting times were twice as long for patients catheterized by cardiologists off-site vs those referred by on-site practitioners (P < 0.0001, after controlling for urgency scores); a similar form of bias was found at a second coronary surgery centre (P = 0.056, after controlling for urgency scores). Over half the patients waited longer than the maximum suggested for their category by the expert panel.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiology Service, Hospital↗
PubMed1992

Antibody responses to natural Dictyocaulus viviparus exposure in first year grazing cattle using vaccination or different kinds of anthelmintic treatment.

In two field trials vaccination or different anthelmintic treatments against Dictyocaulus viviparus infections were used in 6 groups of first year grazing cattle. The antibody response to lungworm infections was determined using an ELISA. Cattle treated once or repeatedly at long intervals with levamisole developed clinical signs of dictyocaulosis. The detection of anti-D. viviparus antibodies at the end of the grazing season confirmed that these anthelmintic treatments were not able to prevent lungworm infections. Cattle that received strategically administered treatments with ivermectin remained clinically healthy. These cattle were seronegative until the end of the trial which proved the efficacy of the strategic control. Cattle that received an intraruminal slow release bolus did not develop clinical disease. However one animal shed lungworm larvae and the herd became seropositive at the end of the grazing season indicating a history of infection. The serological examination of a cattle herd at the end of the grazing season is able to demonstrate a history of lungworm infections and to determine the efficacy of anthelmintic control measures.

Animals↗
PubMed1991

Cyclosporine for plaque-type psoriasis. Results of a multidose, double-blind trial.

BACKGROUND: Severe plaque-type psoriasis has been successfully treated with orally administered cyclosporine, but there has been no comparative, controlled evaluation of various dosages and their efficacy and side effects. METHODS: In a 16-week, double-blind trial, we randomly assigned 85 patients with severe psoriasis to receive 3, 5, or 7.5 mg of cyclosporine per kilogram of body weight per day or a placebo consisting of the vehicle for the drug. After eight weeks the dose could be adjusted to improve safety or efficacy while maintaining blinding. RESULTS: The psoriasis improved in a dose-dependent fashion. After eight weeks of fixed-dose therapy, 36, 65, and 80 percent of the patients receiving 3, 5, and 7.5 mg of cyclosporine per kilogram per day, respectively, were rated as being clear or almost clear of psoriasis; each group had significant improvement (P less than 0.0001) as compared with the group receiving vehicle, in which none of the patients were rated as clear or almost clear. The patients who received 5 mg per kilogram were the least likely to require dosage adjustments because of side effects or a lack of efficacy. The glomerular filtration rate, measured in a subgroup of 34 patients receiving cyclosporine, decreased by a median of 16 percent. Higher doses of cyclosporine had greater adverse effects on systolic blood pressure, glomerular filtration rate, and serum levels of creatinine, uric acid, bilirubin, and cholesterol. Delayed-type hypersensitivity reactions to skin-test antigens were reduced by cyclosporine administration. Cyclosporine appears to become concentrated in skin. CONCLUSIONS: Cyclosporine therapy leads to a rapid and thorough clearing of psoriasis; an initial dose of 5 mg per kilogram per day seems to be appropriate. However, the safety of cyclosporine for the long-term treatment of psoriasis remains to be determined.

Administration, Oral↗
PubMed1991

Assertiveness: an interpersonal approach.

As all aspects of industry and the public sector are reorganised to face the onslaught of the current recession, as well as the impact of a single European market in 1992, so the role and function of OH changes within these organisations. Personal skills of OH nurses that have been adequate in the past may now need to be refined to meet the challenges of the 90s, writes Sue Wheeler lecturer in management development at Birmingham University.

Assertiveness↗