Biomedical subjects

M Stewart

Publications and source records attributed to M Stewart.

At least 217 records · Page 12Linked to original sources

PubMed1996

The effect of respirator training on the ability of healthcare workers to pass a qualitative fit test.

OBJECTIVES: To determine the effect of different methods of training on the ability of hospital workers to wear respirators and pass a qualitative fit test, and to compare the direct cost of the training. DESIGN: 179 hospital employees were recruited for study and were stratified into three groups based on the type of training they received in the use of respirators. Employees in Group A received one-on-one training by the hospital's industrial hygienist and were fit tested as part of this training. Employees in Group B received classroom instruction and demonstration by infection control nurses in the proper use of respirators, but were not fit tested as part of training. Employees in Group C received no formal training. Each participant in our study underwent a subsequent qualitative fit test using irritant smoke to check for the employee's ability to adjust correctly the fit and seal of the respirator. The direct cost of each method of training was determined by accounting for the cost of trainers and the cost of employee-hours lost during training. SETTING: 775-bed Veterans' Affairs hospital. RESULTS: 94% of Group A participants (49 of 52) passed the qualitative fit test, compared to 91% of Group B participants (58 of 64) and 79% of Group C participants (50 of 63; P = .036, 2 x 3 chi-square). Group A had a significantly higher pass rate than Group C (P = .043), but Group B did not differ significantly from Group A or Group C. Location or professional status did not affect pass rate, but prior experience wearing respirators did. When the study groups were compared after stratifying for prior experience, we found no difference in pass rates, except when Groups A and B (those with any training) were combined and compared with Group C (107 of 116 versus 50 of 63, P = .05, Mantel-Haenszel chi-square). We estimate that the method of training involving individual instruction followed by fit testing took 20 minutes per employee to complete, compared to 10 minutes per six employee class for the method of classroom demonstration. The difference in direct cost between the two methods, applied to the training of 1,200 employees at our hospital, would be approximately $19,000 per year. CONCLUSION: Our study indicates that training in the proper use of respirators is important, but the method of training may not be, as the two methods we evaluated were nearly equivalent in their pass rates on fit testing (94% versus 91%). Fit testing as part of training may have enhanced the performance of our participants marginally, but was more time consuming and accounted for most of the excess cost.

Chi-Square Distribution↗

PubMed1996

Creating health with chronic illness.

Within the current context of health care, health promotion for individuals with chronic illness often reflects the priorities of disease-specific preventive care needs and related physical, social, emotional, and spiritual well-being. This article reports a phenomenological study of how older people with chronic illness experience health and health promotion and illuminates a different perspective of health resources and strategies. The findings have profound implications for nursing practice and theory, suggesting the need for restructuring work assignments and refocusing nursing care more clearly away from the medical model.

Adaptation, Psychological↗

PubMed1996

til-1: a novel proviral insertion locus for Moloney murine leukaemia virus in lymphomas of CD2-myc transgenic mice.

Moloney murine leukaemia virus (MoMLV) markedly accelerates thymic lymphoma development in mice carrying a transgene in which the human c-myc gene is linked to the CD2 locus control region. To investigate the mechanism of synergy and identify the genes which collaborate with myc in these clonal tumours, we analysed the sites of MoMLV insertion. Analysis of known viral integration loci revealed only a small number of insertions at bmi-1, pim-1 and ahi-1. Further cloning and hybridization analysis revealed a new common integration locus, designated til-1, which was occupied in 25 out of 77 lymphomas examined, with evidence of multiple clonal insertions in some cases. Mapping relative to established chromosomal markers in interspecific backcross mice located til-1 to mouse chromosome 17, distal to pim-1 and tic-1. These results suggest that the til-1 locus may harbour a novel myc-collaborating gene which acts as a target for activation in T cell lymphomas.

Animals↗

PubMed1996

Predictive value of preschool surveillance in detecting learning difficulties.

OBJECTIVES: The Hall report specified the early detection of mild to moderate learning difficulties as one aim of child health surveillance (CHS). This study examines the efficacy of preschool CHS in the early recognition of children with these disorders. DESIGN: A retrospective case-control study. SUBJECTS: All children (n = 408) with mild to moderate learning difficulties born between 1 July 1983 and 30 June 1984 and resident in North and West Belfast. CONTROLS: 2406 birth records and 150 full child health records controlled for age and geographical area. RESULTS: The prevalence of mild to moderate learning difficulties in North and West Belfast was 16%. Only 6% of children with learning difficulties were identified by the CHS in the preschool period, although the detection rate for children eventually requiring placement in schools for moderate learning difficulties was better. Coverage of the CHS ranged from 90% at the 2 year examination to 98% at the 4 year examination. Perinatal variables associated with learning difficulties after multiple logistic regression analysis were lower social class (odds ratio (OR) 3.9), prematurity < 35 weeks (OR 3.0), male sex (OR 1.6), and birth to an unmarried mother (OR 0.6). Independent preschool variables identified by the CHS were speech delay (OR 3.3), poor parenting skills (OR 4.0), behaviour problems (OR 2.8), enuresis (OR 2.4), poor visual acuity (OR 1.8), and otitis media with effusion (OR 1.4). A statistical model for the early detection of learning difficulties using these risk factors is unable to predict accurately the children who will develop mild to moderate learning difficulties. CONCLUSIONS: The CHS as it existed from 1983 to 1989 in North and West Belfast was poorly sensitive to the detection of mild to moderate learning difficulties despite excellent coverage. An accurate predictive model for learning difficulties could not be developed from the risk factors documented by the CHS.

Case-Control Studies↗

PubMed1996

Changes in lymphocyte subsets, interleukin 2, and soluble interleukin 2 receptor in old and very old age.

In this study, the changes in some of the cellular components of the immune system and the activity of the cytokine interleukin 2, important for immune activation and lymphocyte proliferation, were measured in a large cross-sectional study of all age groups including octogenarian and nonagenarian subjects. In 206 apparently well community-living subjects, the absolute lymphocyte count and T and B cell numbers fell a little in old and very old subjects. Within the T cell compartment, helper/inducer CD4+ T cells, together with their subsets identified as 'naive' (CD4+/CD45RA+) and 'memory' (CD4+/CD45RO+) cells, also showed a decline with increased age. The suppressor/cytotoxic CD8+ subset showed no age-related change. The levels of the cytokine interleukin 2 were very low in octogenarian and nonagenarian subjects, while the soluble interleukin 2 receptor levels increased with increasing age. The interleukin 2 levels were associated with number and percentage of the 'memory' (CD4+/CD45RO+) subset of T cells which mediates the host response to previously met antigens. Since the interleukin 2 values were very low in the oldest groups and were associated with a reduced 'memory' (CD4+/CD45RO+) compartment, this suggests a possible mechanism of why the very elderly subject is more susceptible to morbidity and mortality from infectious or other agents.

Adult↗

PubMed1996

Malignant peripheral nerve sheath tumour with vascular differentiation: a report of four cases.

Four cases of malignant peripheral nerve sheath tumour showing vascular differentiation are described. One case was associated with neurofibromatosis 1 and contained angiosarcomatous, cartilaginous and rhabdomyoblastic elements. The other cases occurred in patients without neurofibromatosis and showed a spectrum of vascular lesions ranging from lobulated, haemangioma-like structures to angiosarcoma. These are the first recorded examples of this phenomenon not associated with neurofibromatosis. Immunohistochemical examination demonstrated the endothelial nature of the lesions in all cases and revealed cells positive for alpha-smooth muscle actin, probably pericytes, closely apposed to the endothelium.

Adult↗

PubMed1995

GLUT-3 (brain-type) glucose transporter polypeptides in human blood platelets.

Antiserum directed against a C-terminal peptide of the human GLUT-3 (brain type) equilibrative glucose transporter isoform reacted with polypeptides M(r) 46,000-48,000 on immunoblots of human platelets. Photoirradiation of human platelets in the presence of 3H-cytochalasin B led to radiolabeling of polypeptides of identical mobility. This labeling was substantially reduced by preincubation the cells with 440 mM D-glucose, but not 440 mM L-glucose, consistent with glucose transporter function. Only traces of GLUT-1 (erythrocyte type) glucose transporter polypeptides were detected, and there was no evidence of GLUT-2 (liver type) transporter on immunoblots of platelet proteins.

Animals↗

PubMed1995

Loss of heterozygosity at 9p23 defines a novel locus in non-small cell lung cancer.

Genetic studies have previously demonstrated cytogenetic deletions and allelic imbalance or loss of heterozygosity (LOH) on the p arm of chromosome 9, in a number of tumour types. We have analysed 45 Non-Small Cell Lung Cancers (NSCLC) with a panel of highly polymorphic microsatellite markers on chromosome 9. Our results indicate that loss on 9p is concentrated within the D9S156-D9S161 region with 44% (20/45) LOH, however the area with minimal loss in this set of lung tumours was found at D9S157 (9p23), with 30% LOH (10/33), whereas loss at the IFNA locus was only found in 6% (2/34) tumours. Five of the lung tumours in this study which demonstrated LOH at D9S157 retained heterozygosity at the adjacent informative markers lying centromeric and telomeric to D9S157. No correlations were found between any of the clinico-pathological parameters and LOH on 9p or at the D9S157 locus. The results of this study indicates the presence of a further putative tumour suppressor gene on 9p at the D9S157 locus (9p23) to be most likely involved in the pathogenesis of non-small cell lung cancer.

Carcinoma, Non-Small-Cell Lung↗

PubMed1995

Effective teaching behaviours of rural family medicine preceptors.

OBJECTIVE: To describe effective teaching behaviours of rural family medicine preceptors. DESIGN: Descriptive qualitative study using the critical incident technique. SETTING: Rural Manitoba community practices affiliated with the University of Manitoba's 8-week family medicine/community medicine rotation (clinical clerkship). PARTICIPANTS: All family medicine preceptors and fourth-year medical students involved in two family medicine rotations from Mar. 11 to June 14, 1991. During the first rotation all 12 students and 21 preceptors participated. During the second rotation 12 of the 13 students and 20 of the 21 preceptors participated. The overall response rate was 97%. OUTCOME MEASURES: Effective and less effective preceptor teaching behaviours. RESULTS: During 120 telephone interviews (48 with the students and 72 with the preceptors) 275 critical teaching incidents were elicited. Over 800 teaching behaviours were identified, and seven main categories describing effective teaching behaviours of preceptors were formed: (a) actively involves the student, providing adequate supervision and appropriate independence, (b) develops and fosters a supportive interpersonal relationship with the student to facilitate learning, (c) emphasizes problem solving and the understanding of general principles, (d) balances clinical and teaching responsibilities, (e) demonstrates clinical and professional competence, (f) uses an organized approach, including goal setting and summation, and (g) provides the student with ongoing feedback, assessments and evaluations. CONCLUSION: The teaching behaviours described in this study augment and corroborate findings from previous studies on clinical teaching and provide a better understanding of effective teaching behaviours. The findings suggest a curriculum for a faculty-development program for rural family medicine preceptors.

Canada↗

PubMed1995

Synergy between a human c-myc transgene and p53 null genotype in murine thymic lymphomas: contrasting effects of homozygous and heterozygous p53 loss.

Activation of the c-myc oncogene and functional loss of the p53 tumour suppressor gene are among the most frequently recorded genetic lesions in neoplasia but their combined effect has not previously been investigated. By breeding together mice transgenic for human c-myc (CD2-myc) and mice carrying an inactive p53 allele (p53-/-) we found that these genetic lesions act synergistically in vivo. Offspring carrying the CD2-myc transgene and the homozygous p53 null mutation (p53-/-/CD2-myc) were viable but developed thymic lymphomas with dramatically increased frequency and reduced latency compared to both parental groups. The tumour phenotype was similar to that previously recorded for CD2-myc mice (predominantly CD3+, CD4+8+) but tumour clonal complexity and metastasis was significantly greater in the p53-/-/CD2-myc mice. In contrast, no significant increase in tumour incidence was seen in p53+/-/CD2-myc vs p53+/+/CD2-myc mice over a 6 month observation period. However, the loss of wild type p53 in a proportion of tumour cells in p53+/-/CD2-myc lymphomas suggests that wild type allele loss can occur as a late progression step rather than an initiating step in these tumours. We suggest that p53 loss of function may collaborate with the CD2-myc transgene at more than one stage in thymic lymphoma development.

Animals↗

PubMed1995

Cell membrane dynamics and insulin resistance in non-insulin-dependent diabetes mellitus.

Insulin resistance in non-insulin-dependent diabetes mellitus (NIDDM) could be related to changes in cell membrane properties. We measured insulin sensitivity and mononuclear leucocyte membrane fluidity by fluorescence polarisation in fifteen NIDDM patients and twenty-one normal subjects. Core-region anisotropy was significantly lower in leucocytes from diabetic subjects (mean 0.164 vs 0.174, p < 0.001). Insulin sensitivity was positively correlated with such anisotropy before and after acute in-vitro insulin treatment. There was no difference in superficial membrane anisotropy. This study suggests that altered membrane dynamics in NIDDM may contribute to insulin resistance.

Cell Membrane↗

PubMed1995

Audiometric referral criteria for industrial hearing conservation programs.

OBJECTIVES: To determine referral rates resulting from application of American Academy of Otolaryngology-Head and Neck Surgery audiometric referral criteria for occupational hearing conservation programs (HCPs) in a large industrial population and to estimate the efficacy of audiometric retesting in identifying false-positive referral flags. DESIGN: Retrospective, comparing referral rates between control and noncontrol HCPs from public domain data in the American National Standards Institute Draft American National Standard: Evaluating the Effectiveness of Hearing Conservation Programs. SETTING: Occupational HCPs from the United States and Canada. PATIENTS: A total of 45,055 baseline and 27,047 second chronologic audiograms were analyzed. A subset of 3958 employees who had baseline and seven subsequent tests were examined to confirm results. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Percent of employees meeting referral criteria was calculated for unconfirmed (ie, single test) and confirmed (two consecutive tests) audiometric findings. No a priori hypotheses were formulated for referral rates for control or noncontrol HCPs. RESULTS: Noncontrol HCP referral rates were typically two to three times that of control HCPs. Control and noncontrol HCPs had about half as many audiometric referral flags when retests were used to confirm initial results. CONCLUSIONS: Mature industrial populations are likely to yield higher baseline referral rates than younger populations. Retesting may identify up to 50% of audiometric referral flags as false-positive and significantly reduce costly overreferrals. Annual referral rates of 1% to 2% seem to be achievable in well-run HCPs in which retesting is performed to identify false-positive audiometric outcomes.

Audiology↗

PubMed1995

A method allowing intracellular and extracellular single-unit recordings from brain slices in the grease-gap chamber.

The grease-gap chamber makes it possible to perfuse two parts of a brain slice separately. Hence, it lies between bath application and iontophoresis or pressure ejection in terms of the size of the region that receives controlled drug dosing. Modifications of a commercially available chamber are described which have permitted the first extracellular and intracellular single-unit recordings to be taken from brain slices in a grease-gap preparation. In addition, we describe the electrical resistance of the gap as a measure of the integrity of the barrier and a simple method for monitoring this resistance continuously. The resistance monitor is particularly useful during low flow rate conditions that improve mechanical stability. These techniques extend the grease-gap method to electrophysiological studies of single cells in slices.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed1995

Infection after colorectal surgery: a randomized trial of prophylaxis with piperacillin versus sulbactam/piperacillin. West of Scotland Surgical Infection Study Group.

Antibiotics used for prophylaxis in elective colorectal surgery should be effective against the organisms contaminating the soft tissues and isolated from postoperative infections. These are usually the enterobacteriaceae commensal to the colon. However, staphylococcal and anaerobic infections are not uncommon. Piperacillin has been used as antibiotic prophylaxis and been shown to be as efficacious as an aminoglycoside with metronidazole. Piperacillin is susceptible to many beta-lactamases and we have therefore conducted a study to assess the efficacy of adding sulbactam, a beta-lactamase inhibitor, to piperacillin for prophylaxis in elective colorectal surgery. Three hundred and seventy-nine patients were randomized to receive a single dose of piperacillin 4 g intravenously (iv) (group P, n = 192) or piperacillin 4 g with sulbactam 2 g iv (group SP n = 187). Fifty-three patients were withdrawn from analysis leaving 168 evaluable patients in group P and 158 patients in group SP. Postoperative infective complications occurred in 91 (28%) patients, 55 (33%) in group P and 36 (23%) in group SP (chi 2 = 4.0 P < 0.05). Surprisingly Staphylococcus aureus was isolated from wound infections in 22 patients (12 in group P and 10 in group SP) which represents 24% of those patients who developed infective morbidity. We conclude that sulbactam improves the efficacy of piperacillin as prophylaxis in elective colorectal surgery but does little to protect against staphylococcal wound infection.

Adolescent↗

PubMed1995

Nematode sperm locomotion.

The simplicity and specialization of the amoeboid motility of nematode sperm can give intriguing insights into the molecular mechanisms underlying movement in more conventional actin-based systems. Amoeboid motility in nematode sperm is based on their major sperm protein. Advances over the past year in understanding the assembly of this protein in vivo and in vitro have underlined the importance of vectorial assembly and filament bundling. In this system, it is possible that these two properties may be sufficient to generate motility that closely resembles that seen in conventional actin-based systems.

Animals↗

PubMed1995

Leukocyte integrins.

Lymphocytes, monocytes and granulocytes, which are collectively known as 'leukocytes', circulate primarily within the vascular system and lymphoid tissue but are found in essentially all tissues of the body. This mobile lifestyle necessitates the constant making and breaking of adhesive contacts with targets in their immediate environment. The adhesion receptors termed integrins, which are expressed in abundance by leukocytes, are well suited to carry out the transient interactions in which these cells engage. Major advances in the leukocyte integrin field this year have been the realization of the extensive roles for alpha 4 integrins in leukocyte function, the solution of the crystal structure of an I domain and its identification as a major ligand-binding site, and the initial understanding of how divalent cations may function in an active integrin.

Cell Adhesion↗

PubMed1995

Assessment of and intervention for psychosocial problems in routine oncology practice.

An audit was carried out of 51 oncology patients referred to a clinical psychology service to identify the characteristics of patients selected for referral and to assess change following psychological intervention. A survey was conducted of an unselected sample of oncology patients representative of the workload of the oncology department from which the referrals came, to determine the prevalence of comparable psychosocial problems among patients who were not referred for help and to assess whether doctors were aware of the problems patients reported. Data were collected using the Hospital Anxiety and Depression (HAD) and Mental Adjustment to Cancer (MAC) scales and a problem checklist devised for this study. Referred patients were significantly more anxious and depressed (P < 0.001) and showed poorer adjustment on MAC scales than the surveyed sample, but 30% of the latter group warranted assessment for anxiety and 23% for depression. The number of psychosocial problems of their severity. Intervention was clinically significant mood disorder irrespective of the specific problems of their severity. Intervention was associated with a significant improvement in distress and problems for referred patients by the time of discharge. Psychosocial problems were often undetected by staff even in referred patients. The checklist is a feasible screening method for potentially remediable problems which are cumulatively a significant contributor to cancer patients' distress.

Adaptation, Psychological↗

PubMed1995

Swallowing performance following anterior cervical spine surgery.

The aim of this study was to assess the incidence and severity of dysphagia following anterior cervical spine surgery for cervical spondylosis. One-hundred patients were contacted 12-22 months following cervical spine surgery. Those reporting persistent swallowing impairment were invited to attend for further investigation. Of 73 respondents, 33 (45%) experienced postoperative dysphagia. This persisted for longer than 6 months in nine (12% of respondents). Of five subjects attending for investigation, none had a definite radiological abnormality. In contrast, manometry suggested hyperactivity of the pharyngo-oesophageal segment in these patients, although with normal co-ordination. Surgeons should warn of the risk of transient dysphagia in 45% of patients postoperatively and of its persistence in around 10%. Radiological examination may be normal and manometry is the investigation of choice. Persistent, severe dysphagia may be ameliorated by cricopharyngeal myotomy or pharyngeal dilatation.

Adult↗