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Biomedical subjects

S Reid

Publications and source records attributed to S Reid.

At least 91 records · Page 5Linked to original sources

Prefrontal cortex dysfunction in Borna disease virus (BDV)--infected rats.

Viruses have been proposed to play a role in the pathogenesis of schizophrenia; however, the mechanisms by which infection could cause the affective, cognitive, and movement disorders of schizophrenia are not understood. The neurotropic RNA virus, Borna disease (BD) virus, linked to schizophrenia by serologic studies, causes movement and behavior disorders in a wide variety of mammalian and bird hosts. BD rats have hyperactivity and stereotyped behaviors similar to those that follow neurotoxic or electrolytic lesions in frontal cortex or its catecholamine afferents in rats. BD rats have high levels of viral nucleic acid in the prefrontal cortex (PFC), abnormal mesocortical dopamine activity (elevated levels of DOPAC in PFC), yet no alteration in specific binding of D1 or D2 receptor radioligands in PFC. Since frontal lobe dysfunction is frequently reported in schizophrenia, the BD rat model may provide insights into pathogenesis and management of this debilitating psychiatric disease.

3,4-Dihydroxyphenylacetic Acid↗

Combined Hoechst 33342 and merocyanine 540 staining to examine murine B cell cycle stage, viability and apoptosis.

A procedure is described for the dual staining of lymphocytes with Hoechst 33342 (Ho342) to examine cell cycle position, and merocyanine 540 (MC540) that allows for the analysis of cells entering the early stages of apoptosis. Ho342 is a DNA specific dye and MC540 detects membrane phospholipid domain changes, some of which are associated with apoptotic cells. Flow analysis of B cells dually stained with Ho342 and MC540 allows for the discrimination of five distinct subpopulations. Two of these subpopulations represent viable, MC540 negative/dull cells with either 2n or 4n DNA. As 2n and 4n DNA B cells become MC540 bright they move into two distinct subpopulations representing cells entering and progressing through the early stages of apoptosis. As the apoptotic, MC540 bright cells move into the latter stages of apoptosis, they localize into a fifth subpopulation displaying reduced staining with Ho342 indicative of late stage apoptotic cells in the process of fragmenting their DNA. This experimental approach enables the characterization of lymphocyte populations for percentages of viable, early apoptotic, and late apoptotic cells. The cells are not fixed during this procedure, and since both dyes are viable dyes there is an additional opportunity to obtain sorted cells from any of the defined subpopulations for reculturing and functional analysis.

Animals↗

Early prediction of chronic disability after occupational low back injury.

STUDY DESIGN: An inception cohort design was used to study a consecutive sample of back-injured workers. OBJECTIVE: To refine and to test the Vermont Disability Prediction Questionnaire's ability to indicate an individual's relative risk for chronic disability after occupational low back injury. SUMMARY OF BACKGROUND DATA: Although most back-injured workers return to work quickly, the minority who do not account for the majority of associated costs and health care. Early identification of workers at high risk for disability would facilitate intervention strategies. METHODS: During the study recruitment period, people aged 18-60 years reporting occupational low back injury to the Vermont Department of Labor and Industry within 11 days of onset were eligible. A Vermont Disability Prediction Questionnaire was mailed to the 442 subjects who could be contacted and who gave informed consent. One hundred sixty-three of the 166 subjects who completed and returned the questionnaire within 15 days of initial injury were telephoned 3 months later to determine work status. Those who returned the questionnaire were compared with those who would not consent or did not return the questionnaire in time according to age, sex, residence, wages, work hours per week, and length of employment. Employment status (inability to work because of low back pain) was evaluated by telephone interview 3 months after initial injury. RESULTS: The follow-up interviewer was blinded to the Vermont Disability Prediction Questionnaire scores. of the 163 subjects, 16 (10%) were not working because of low back pain. Using a simple dichotomous scoring system for 11 questionnaire items, a cut-off score of 0.48 identified 3-month postinjury work status, with 0.94 sensitivity and 0.84 specificity. CONCLUSIONS: The Vermont Disability Prediction Questionnaire is a brief, easily administered and scored tool for identifying back-injured workers at relative risk for chronic disability. Such early identification should increase the efficiency of disability prevention strategies by directing them toward people who need them most. The accuracy of the questionnaire needs to be tested in a variety of different clinical and socioeconomic settings.

Adult↗

The regulated expression of cell cycle-related proteins as B-lymphocytes enter and progress through the G1 cell cycle stage following delivery of complete versus partial activation stimuli.

Resting B-cells lack both cyclins D and E while constitutively expressing low levels of cdk4 and cdk2. B-cells receiving a complete growth stimulus express cyclin D2 by 10hr and cyclin E by 10-24hr poststimulation while increasing their protein levels of cdk4 and cdk2. B-cells receiving partial growth stimuli move into G1 without passing the G1 restriction point and transiently increase cyclin D2 mRNA levels without accumulating cyclin D2 protein. In the absence of cyclin D2 accumulation, cdk4 is not activated, and cyclin E is not expressed. These results suggest that signals responsible for moving B-cells through the G1 restriction point impact at the level of cyclin D2 protein accumulation. The possible implications of these results are discussed.

Animals↗

Improved method for counting virus and virus like particles.

An improved method for counting virus and virus like particles by electron microscopy (EM) was developed. The procedure involves the determination of the absolute concentration of pure or semi-pure particles once deposited evenly on EM grids using either centrifugation or antibody capture techniques. The counting of particles was done with a Microfiche unit which enlarged approximately 50 x the image of particles on a developed negative film which had been taken at a relatively low magnification (2500 x) by EM. Initially, latex particles of a known concentration were counted using this approach, to prove the accuracy of the technique. The latex particles were deposited evenly on an EM grid using centrifugation (Modified Beckmen EM-90 Airfuge technique). Subsequently, recombinant Bluetongue virus (BTV) core-like particles (CLPs) captured by a Monoclonal antibody using a novel sample loading method were counted by the Microfiche unit method and by a direct EM method. Comparison of the simplified counting method developed with a conventional method, showed good agreement. The method is simple, accurate, rapid, and reproducible when used with either pure particles or with particles from crude cell culture extracts.

Antibodies, Monoclonal↗

The effect of size on uptake of orally administered latex microparticles in the small intestine and transport to mesenteric lymph nodes.

PURPOSE: The present study examines the relationship between size and particle transit across the mucosal barrier of the gastrointestinal tract to other sites of the body. The extent of particle uptake with increasing size, the tissue distribution and cut-off points for 2-20 microns particles is investigated. METHODS: An established fluorescent latex particle-young adult rat model is used and particle numbers in small intestine and mesenteric lymph nodes, 0.5 h post administration, counted by fluorescence microscopy in bulk tissue specimens and cryosections. RESULTS: Bulk tissue analysis provides evidence for the presence of particles of all sizes in the Peyer's patch regions, but only for 2 microns particles in the nodal tissues. Microscopy establishes uptake of both 2 and 6 microns particles in most intestinal and nodal tissue sites and compartments. By contrast, uptake of the larger particles is much reduced. CONCLUSIONS: Although more of the smaller (2 microns) particles are taken up, particularly by epithelial tissues, the 6 microns size appears more efficient in terms of volume translocated to lymph nodes. This could have implications in the therapeutic use of particles for drug and vaccine delivery and for radiation safety.

Animals↗

Double-blind, placebo-controlled trial of topiramate as add-on therapy in patients with refractory partial seizures.

In a double-blind, randomized, parallel-group trial, we compared topiramate (TPM) with placebo as add-on therapy in patients with refractory partial epilepsy. TPM was titrated either to the target dosage of 800 mg/ day [400 mg twice daily (b.i.d)] or to the maximal tolerated dose if lower. Twenty-eight (28) patients were randomized to each treatment group. In the intent-to-treat analysis, the net median percent reduction relative to placebo in average monthly seizure rate was 54% for patients in the TPM group (p < 0.001). None of the placebo-treated patients and 43% of the patients treated with TPM experienced > or = 50% reduction in seizures (p = 0.001), and 36% of patients assigned to TPM had a 75-100% reduction in seizures (p < 0.01). Secondarily generalized seizures were also significantly reduced in the TPM group (p = 0.044). The most common adverse events (AE) reported in the TPM group were fatigue, impaired concentration, weight loss, dizziness, and paresthesias. AE occurring either during the rapid titration of TPM or at high dosages led 21% of TPM-treated patients to withdraw from the study. Half of these occurred during the titration study period. No serious AE or clinically important changes in clinical laboratory measures were observed. The present study further establishes the favorable profile and good benefit/risk ratio of TPM in resistant partial epilepsy.

Adolescent↗

The effects of repeated physical stress on the b-adrenergic response of the rainbow trout red blood cell

The effects of a 7-day period of daily physical stress (chasing until exhaustion) on the beta-adrenergic response of the rainbow trout (Oncorhynchus mykiss) red blood cell (rbc) were examined in vitro. Physical stress was associated with pronounced increases in the circulating levels of the catecholamine hormones (adrenaline and noradrenaline) measured on days 1, 3 and 7 of the stress regime. After 7 days, the numbers of high-affinity cell surface beta-adrenoceptors were reduced in the physically stressed fish when measured in vitro under conditions of normoxia (20 % reduction) or hypoxia (30 % reduction). Under hypoxic conditions, the binding affinity of the rbc beta-adrenoceptor was significantly higher in the stressed fish. Although the stressed fish had fewer beta-adrenoceptors, rbc adrenergic responsiveness was enhanced after 7 days of physical stress as determined from dose-response curves relating noradrenaline concentration to water and Na+ accumulation (indices of rbc adrenergic Na+/H+ exchange activity). The EC50 values (concentrations yielding half-maximal responses) for noradrenaline were lowered significantly by 1.7- to 3.9-fold in the blood from physically stressed fish. The enhanced adrenergic responsiveness of the rbcs appeared to be unrelated to changes in the initial steps of the beta-adrenergic signal transduction pathway leading to cyclic AMP production because physical stress was without effect on the magnitude or the dose-dependency of rbc cyclic AMP accumulation. To determine whether post-cyclic-AMP events were affected by physical stress, water and Na+ accumulation were measured in rbcs that had been incubated with the permeable cyclic AMP analogue 8-bromo cyclic AMP. The EC50 values for 8-bromo cyclic AMP were lowered by 1.6- to 1.7-fold in the blood from stressed fish. These experiments demonstrate that repeated physical stress significantly enhances the adrenergic responsiveness of the rainbow trout rbc, presumably by modifying the sensitivity of the Na+/H+ exchanger (or the steps immediately preceding exchanger activation) to cyclic AMP. The results are discussed with respect to the interrelationships between chronic and acute stress responses in fish.

Journal Article↗

Warfarin prescribing.

The incident Monitoring in General Practice Project began as an initiative of the Professional Indemnity Review. Anonymous data from general practitioners about unintended, and possibly adverse events were collected in order to develop preventive strategies that might ultimately increase patient safety and therefore reduce litigation. Feedback and sharing of experiences and ideas about these events, possible management strategies or the project as a whole are invited from the readers.

Anticoagulants↗

Clinical incidents in general practice. Communication between casualty departments and general practitioners.

The incident Monitoring in General Practice Project began as an initiative of the Professional Indemnity Review. Anonymous data from general practitioners about unintended, and possibly adverse events were collected in order to develop preventive strategies that might ultimately increase patient safety and therefore reduce litigation. Feedback and sharing of experiences and ideas about these events, possible management strategies or the project as a whole are invited from readers.

Australia↗

Clinical incidents in general practice. A difficult paediatric diagnosis.

The Incident Monitoring in General Practice Project began as an initiative of the Professional Indemnity Review. Anonymous data from general practitioners about unintended, and possibly adverse events were collected in order to develop preventive strategies that might ultimately increase patient safety and therefore reduce litigation. Feedback and sharing of experiences and ideas about these events, possible management strategies or the project as a whole are invited from readers.

Child↗

Clinical incidents in general practice. Prescription errors.

The incident Monitoring in General Practice Project began as an initiative of the Professional Indemnity Review. Anonymous data from general practitioners about unintended, and possibly adverse events were collected in order to develop preventive strategies that might ultimately increase patient safety and therefore reduce litigation. Feedback and sharing of experiences and ideas about these events, possible management strategies or the project as a whole are invited from the readers.

Anti-Inflammatory Agents, Non-Steroidal↗

Clinical incidents in general practice. Keeping on track with test results.

The incident Monitoring in General Practice Project began as an initiative of the Professional Indemnity Review. Anonymous data from general practitioners about unintended and possibly adverse events were collected in order to develop preventive strategies that might ultimately increase patient safety and therefore reduce litigation. Feedback and sharing of experiences and ideas about these events, possible management strategies or about the project as a whole are invited from readers.

Australia↗