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Biomedical subjects

M Cameron

Publications and source records attributed to M Cameron.

At least 37 records · Page 2Linked to original sources
PubMed1999

Electrical stimulation of wrist extensors in poststroke hemiplegia.

BACKGROUND AND PURPOSE: It has been suggested that cyclic neuromuscular electrical stimulation (ES) may enhance motor recovery after stroke. We have investigated the effects of ES of the wrist extensors on impairment of wrist function and on upper-limb disability in patients being rehabilitated after acute stroke. METHODS: We recruited 60 hemiparetic patients (mean age, 68 years) 2 to 4 weeks after stroke into a randomized, controlled, parallel-group study comparing standard rehabilitation treatment with standard treatment plus ES of wrist extensors (3 times 30 minutes daily for 8 weeks). Isometric strength of wrist extensors was measured using a device built for that purpose. Upper-limb disability was assessed with use of the Action Research Arm Test (ARAT). Observations were continued for 32 weeks (24 weeks after the finish of ES or the control intervention phase). RESULTS: The change in isometric strength of wrist extensors (at an angle of 0 degrees extension) was significantly greater in the ES group than the control group at both 8 and 32 weeks (P=0.004, P=0.014 by Mann Whitney U test). At week 8 the grasp and grip subscores of the ARAT increased significantly in the ES group compared with that in the control group (P=0.013 and P=0.02, respectively); a similar trend was seen for the total ARAT score (P=0.11). In the subgroup of 33 patients with some residual wrist extensor strength at study entry (moment at 0 degrees extension >0), the ARAT total score had increased at week 8 by a mean of 21.1 (SD, 12.7) in the ES group compared with 10.3 (SD, 9.0) in the control group (P=0.024, Mann Whitney U test); however, at 32 weeks the differences between these 2 subgroups were no longer statistically significant. CONCLUSIONS: ES of the wrist extensors enhances the recovery of isometric wrist extensor strength in hemiparetic stroke patients. Upper-limb disability was reduced after 8 weeks of ES therapy, with benefits most apparent in those with some residual motor function at the wrist. However, it is not clear how long the improvements in upper-limb disability are maintained after ES is discontinued.

Aged↗
PubMed1998

TCR alpha beta chains associate with the plasma membrane independently of CD3 and TCR zeta chains in murine primary T cells.

The TCR is a multisubunit complex composed of the clonotypic alpha/beta disulfide-linked heterodimer and noncovalently linked invariant CD3 gamma epsilon and CD3 delta epsilon and TCR zeta chains. Recent studies demonstrate that the surface expression of CD3 components can occur independently of the clonotypic TCR complexes in both thymocytes and splenic T cells. In this study, we report that free noncovalently associated TCR alpha beta heterodimers that exist independently of CD3 and TCR zeta chains are expressed on the cell surface of immature thymocytes and peripheral T cells, but not of T cell lines and T cell hybridomas. This suggests that the regulation of surface expression of TCR alpha beta heterodimers differs between primary T cells and T cell lines or T cell hybridomas. The isolation and biochemical characterization of surface clonotype-independent CD3 complexes and free membrane-associated TCR alpha beta complexes may provide a structural basis for the quantitative difference in amount of T cell proliferation stimulated by anti-CD3 epsilon and anti-TCR beta.

Animals↗
PubMed1997

Impaired plasma membrane targeting of Grb2-murine son of sevenless (mSOS) complex and differential activation of the Fyn-T cell receptor (TCR)-zeta-Cbl pathway mediate T cell hyporesponsiveness in autoimmune nonobese diabetic mice.

Nonobese diabetic (NOD) mouse thymocytes are hyporesponsive to T cell antigen receptor (TCR)-mediated stimulation of proliferation, and this T cell hyporesponsiveness may be causal to the onset of autoimmune diabetes in NOD mice. We previously showed that TCR-induced NOD T cell hyporesponsiveness is associated with a block in Ras activation and defective signaling along the PKC/Ras/MAPK pathway. Here, we report that several sequential changes in TCR-proximal signaling events may mediate this block in Ras activation. We demonstrate that NOD T cell hyporesponsiveness is associated with the (a) enhanced TCR-beta-associated Fyn kinase activity and the differential activation of the Fyn-TCR-zeta-Cbl pathway, which may account for the impaired recruitment of ZAP70 to membrane-bound TCR-zeta; (b) relative inability of the murine son of sevenless (mSOS) Ras GDP releasing factor activity to translocate from the cytoplasm to the plasma membrane; and (c) exclusion of mSOS and PLC-gamma1 from the TCR-zeta-associated Grb2/pp36-38/ZAP70 signaling complex. Our data suggest that altered tyrosine phosphorylation and targeting of the Grb2/pp36-38/ZAP70 complex to the plasma membrane and cytoskeleton and the deficient association of mSOS with this Grb2-containing complex may block the downstream activation of Ras and Ras-mediated amplification of TCR/CD3-mediated signals in hyporesponsive NOD T cells. These findings implicate mSOS as an important mediator of downregulation of Ras signaling in hyporesponsive NOD T cells.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Assessing the impact of community violence on children and youths.

Social workers often encounter young clients who have been exposed to violence in their communities. Although the devastating effects of community violence have been well documented, surprisingly little concern in social work practice has been focused on attending to young clients' experiences with community violence. This article explores the manifestations and consequences of community violence in the lives of children and youths and presents an assessment framework with which social workers may examine the impact of community violence in the lives of their young clients at risk.

Adolescent↗
PubMed1997

Cost implications of allergy and recent Canadian research findings.

The cost to hospital's managing latex allergy problems, and of instituting a co-operative response to the problem is estimated, and compared with the estimated cost of ignoring the problem. The costs and benefits of the interventional strategies, i.e. complete elimination of powdered latex gloves in favour of powder free latex gloves, are described in detail. It is demonstrated that the chosen interventional strategy not only reduced overall costs, but surprisingly, also reduced glove purchase costs.

Canada↗
PubMed1996

A pilot diabetes awareness and exercise programme in a multiethnic workforce.

AIMS: To evaluate the acceptability and impact of a pilot diabetes awareness and exercise programme in a mainly Polynesian workforce. METHOD: Comparison of change in questionnaire and anthropometric measurements in two hospital ancillary workforces. One group (n = 108) received one community diabetes educator presentation, one video presentation and a 4 month exercise programme. The other group (n = 99) served as controls. RESULTS: Baseline diabetes knowledge was poor (total score 26 (SD 13%)) and subjects were largely unfit with a high body mass index (31.5 (7.1) kg/m2). The exercise sessions were well attended, although attendance declined over the 4 months. Increased diabetes knowledge was retained in the intervention group after 6 months when compared with controls (total score 35(14)% vs 26(12)% respectively, p < 0.001). One month after the termination of the programme, the proportion reporting regular exercise activity (at least 30 minutes for 3 days per week) had increased by 2% in the intervention group but declined by 9% in the control group (p < 0.05). CONCLUSIONS: Diabetes knowledge and exercise can be increased in unfit subjects by the combination of culturally tailored exercise techniques and community diabetes educator/video presentations.

Adult↗
PubMed1996

Attentional bias in obsessional compulsive disorder.

To date, studies of information processing in anxiety disorders have suggested that the latter are characterised by vigilance for threatening stimuli, possibly specific to personally relevant threat content. The present study represents an attempt to establish whether patients suffering from Obsessional Compulsive Disorder (OCD), generally classified as an anxiety disorder, show a similar cognitive bias. Thus, a replication of MacLeod, Mathews and Tata's (1986) study [Journal of Abnormal Psychology, 95, 15-20] is reported, employing modified materials of direct concern to the OCD subjects i.e. Contamination-related words. The results did indeed reveal content specific vigilance, whereby the OCD group were more vigilant for contamination content than mood-matched High Trait Anxious (HTA) controls, but the reverse was true for Social Anxiety words. Additionally, while a general threat interference effect was identified for both OCD and HTA subjects this was not content specific. A second experiment employing Low Trait Anxious subjects revealed no vigilance for threat nor any threat interference in this sample. The clinical implications and possible mechanism underlying these results are discussed.

Adult↗
PubMed1996

The fucosyltransferase FucT-VII regulates E-selectin ligand synthesis in human T cells.

Selectin-ligands on T cells contribute to the recruitment of circulating cells into chronic inflammatory lesions in the skin and elsewhere. This report provides the first evidence that a single fucosyltransferase, termed FucT-VII, controls the synthesis of E-selectin ligands in human T-lymphoblasts. The FucT-IV transferase (the ELFT enzyme), in contrast constructs lower avidity E-selectin ligands and requires enzyme levels found only in myeloid cells. Treatment of Jurkat cells with phorbol myristate acetate increased the expression of sialylated Lewis(x)-related sLe(x)related epitopes and induced the synthesis of E-selectin ligands functional at physiologic levels of linear shear-stress. Northern analysis revealed a parallel increase in the steady-state levels FucT-VII mRNA, but there were no increases in the two other leukocyte-associated fucosyltransferases (FucT-IV and VI). The stable transfection of the FucT-VII gene into Jurkat cells induced high levels of the sLe(x)-related epitopes and the synthesis of E-selectin ligands which equal or exceeded the avidity of those on circulating lymphocytes. The growth of T-lymphoblasts under conditions which induced expression of the sLe(x,a) epitopes increased the level of FucT-VII mRNA, the synthesis of sialylated-Lewis(x) structures by cell-free extracts and the synthesis of E-selectin ligands equal in avidity to those on FucT-VII transfectants. In contrast, neither the mRNA levels nor activities of the FucT-IV and VI enzymes increased in association with E-selectin ligand synthesis in T-lymphoblasts. Myeloid cell lines, unlike lymphoblasts, expressed high levels of both the FucT-VII and IV enzymes in conjunction with E-selectin ligands raising the possibility that both enzymes contributed to ligand synthesis. FucT-IV transfected Jurkat cells synthesized low avidity ligands for E-selectin but only in association with CDw65 (VIM-2) carbohydrate epitope. Only blood neutrophils and myeloid cell lines expressed this epitope at the levels associated with E-ligand synthesis in the transfectants. In contrast, native Jurkat cells, blood monocytes, blood lymphocytes, and cultured T-lymphoblasts expressed low levels or none. We conclude that FucT-VII is a principal regulator of E-selectin ligand synthesis in human T-lymphoblasts while both FucT-VII and FucT-IV may direct ligand synthesis in some myeloid cells.

Antigens, CD↗
PubMed1995

Imaging protein kinase C activation in living sea urchin eggs after fertilization.

The fluorescent dye NBD-phorbol acetate was used to visualize the activation of protein kinase C (PKC) in living Lytechinus pictus eggs during fertilization. The dye interacts directly with PKC as determined using a competitive binding assay. Quantitative image analysis of sequential images from laser-scanning confocal microscopy showed a significant reorganization of the signal in the vicinity of the cortical granules and the plasma membrane that began immediately following fertilization and persisted up to 1 hr (P<0.0001). At the concentrations employed, the NBD-phorbol dye was not capable of inducing a significant translocation of the fluorescent signal to the membrane, nor did it appear to interfere with the cell cycle. It therefore seems likely that the present in vivo results reflect the previously reported in vitro activation of protein kinase C immediately subsequent to fertilization. Such an interpretation is parsimonious with the results of parallel subcellular fractionation experiments using an N-terminal polyclonal antibody to sea urchin PKC which showed a significant (P<0.037) translocation of the enzyme from the cytosolic fraction to the membrane fraction 40 min subsequent to fertilization. This study supports and extends previous in vitro data suggesting that PKC activation subsequent to fertilization occurs at or near the egg plasma membrane, perhaps in association with arachadonic acid-rich cortical granules.

Animals↗
PubMed1995

Difference in prevalence of gestational diabetes and perinatal outcome in an innercity multiethnic London population.

In order to establish the prevalence of gestational diabetes mellitus (GDM) among ethnic groups residing in the catchment area of one hospital in central London and to assess both the mode of delivery and the baby outcome, we studied retrospectively 703 women selected for screening for GDM during the years 1991 and 1992. While the prevalence of GDM was approximately 2% overall, within the ethnic groups a significant difference was found with Asians and Africans/Afrocaribbeans being four and two times more likely to have GDM, respectively, than Caucasians (P < 0.001). Both maternal obesity and the diagnosis of GDM influenced the time and the mode of delivery, but perinatal mortality and morbidity did not differ significantly between women with GDM and women with normal glucose tolerance. An association between the GTT glucose area and the gestational age and ethnicity adjusted birth weight was observed in women with normal glucose tolerance test, but was absent in the GDM pregnancies, providing indirect evidence that dietary treatment, with or without insulin treatment, altered the maternal milieu in the latter sufficiently to modify fetal growth.

Adult↗
PubMed1995

In vitro plasma protein binding of neuromuscular blocking agents in different subpopulations of patients.

In vitro protein binding of several neuromuscular blocking agents (NMBAs) was measured by ultrafiltration in plasma from patients susceptible to demonstrate changes in their protein constituents. First, the relationship between the free fraction of atracurium and plasma lipoproteins levels in young volunteers (22-32 yr old, n = 6) and hyperlipidemic patients (44-68 yr old, n = 13) was studied, and second, the free fraction of atracurium, mivacurium, doxacurium, and vecuronium was determined in plasma of healthy young (27-47 yr old, n = 10), elderly (72-89 yr old, n = 11) and obese (21-57 yr old, n = 9, 200%-360% ideal body weight) patients scheduled for elective surgery. In hyperlipidemic patients, atracurium free fraction was significantly less than in young volunteers (40% +/- 5% vs 50% +/- 5%, mean +/- SD), and decreased as total cholesterol, low-density lipoprotein cholesterol and triglycerides increased (P < 0.05). In young individuals, NMBA free fraction was 25% +/- 5% for vecuronium, 58% +/- 8% for doxacurium, 52% +/- 6% for atracurium, and 72% +/- 3%, 70% +/- 3%, 70% +/- 4% for mivacurium trans-trans, cis-trans, and cis-cis isomers, respectively. Higher triglyceride concentrations in obese patients and lower high-density-lipoprotein cholesterol concentrations in both obese and elderly patients were observed when compared with young subjects. However, there was no significant difference in protein binding of NMBAs among these three groups. We conclude that, in otherwise healthy patients, age and weight are not likely to alter the free fraction of NMBAs.

Adult↗
PubMed1995

Latex sensitivity: an occupational health strategic plan.

1. Health care workers, due to ongoing exposure to latex products, may be at risk of developing latex sensitivity. 2. The spectrum of reactions related to medical glove use varies in severity. Awareness of latex sensitivity is heightened through worker education. 3. Guidelines and interventions for occupational health nurses are outlined so that workers who present with symptoms of occupational sensitivities related to latex products can be identified and assessed. 4. Occupational health nurses are effective resources for workers and managers on issues of latex allergy and appropriate accommodation.

Decision Trees↗