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Biomedical subjects

S Duncan

Publications and source records attributed to S Duncan.

At least 55 records · Page 3Linked to original sources
PubMed1990

Achieving parent-child coordination through convention: fixed- and variable-sequence conventions.

Convention provides a major means by which the child can achieve coordinated action with others. One aspect of the structural design of conventions is considered: the composition of a convention's interaction rules. Fixed-sequence conventions, defined as having only obligatory rules, are differentiated from variable-sequence conventions, having at least 1 optional rule. Some interactional effects of the 2 types of conventions are illustrated by a set of fixed- and variable-sequence conventions hypothesized for interaction within 2 families. Fixed- and variable-sequence conventions are placed within the larger context of the state sensitivity of conventions: the degree to which each convention provides both for participants' expressing convention-relevant states and changes in these states, and for their accommodating the interaction to these states and changes--all relevant to achieving coordinated action. The interactional effects of other major sources of state sensitivity are considered and contrasted with those of fixed- and variable-sequence conventions.

Communication↗
PubMed1989

Benzodiazepine antagonism does not provoke a stress response.

Acute anxiety reactions have been reported following antagonism of benzodiazepine-induced sedation. In this study, the level of sedation and anxiety was assessed in 30 patients randomly assigned to receive either saline or flumazenil (a benzodiazepine antagonist) after midazolam sedation according to a double-blind protocol. Carefully titrated doses of flumazenil, 0.8 +/- 0.2 mg (mean +/- SD), effectively reversed residual midazolam-induced sedation without producing significant changes in the patients' level of anxiety. In addition, plasma epinephrine, norepinephrine, vasopressin, and beta-endorphin concentrations were measured in a subset of patients (n = 5) from each group. The levels of these stress hormones did not acutely change following flumazenil (or saline). These results indicate that flumazenil, 0.6-1.0 mg iv, can antagonize midazolam sedation without producing acute anxiety or evidence of a stress response.

Adult↗
PubMed1988

The development of a role charter for nursing unit administrators.

Issues of decentralization and changes in the structure of the traditional Head Nurse role were motivating factors for the proactive stance taken by the Medical-Surgical Head Nurse Group at The Wellesley Hospital. Increasing frustration with the conventional role and the need for a reflective performance appraisal tool provided further impetus for the development of a revised job description. The three departments of nursing each submitted their perception of the role. A task force was established whose mandate was to review and revise the three separate submissions and combine them into a composite document. This article describes the process from the initial motivating factors to the development of a cohesive Total Head Nurse Group and finally a 'Role Charter for Nursing Unit Administrators.'

Humans↗
PubMed1986

High-performance liquid chromatography analysis of the thiobarbituric acid adducts of malonaldehyde and trans,trans-muconaldehyde.

A reversed-phase HPLC method is described for the separation and analysis of the thiobarbituric acid (TBA) adducts of the reactive aldehydes muconaldehyde (MUC) and malonaldehyde (MDA). The TBA adduct of malonaldehyde was synthesized, purified, and its structure elucidated, for use as standard in quantitative HPLC studies. A detection limit of 1 X 10(-14) mol was achieved for the MUC:TBA and MDA:TBA adducts using the double monochromator fluorometric detector, 7 X 10(-13) mol was the detection limit using a variable wavelength uv-visible detector. Direct on-line identification of the eluting aldehyde:TBA adducts was achieved by the use of a diode-array uv-visible detector. The chromatographic behavior of the adducts under different mobile phase conditions was also examined. This HPLC methodology was used for the identification of muconaldehyde as a product of benzene oxidation in a hydroxyl radical generating system.

Aldehydes↗
PubMed1984

The effects of antirheumatic drugs on the production of collagenase and tissue inhibitor of metalloproteinases (TIMP) by stimulated rabbit articular chrondrocytes.

Conditioned medium from human peripheral blood mononuclear cells stimulated with concanavalin A (50 micrograms/ml) was used to induce rabbit articular chondrocytes to produce collagenase. In passaged chondrocyte cultures sodium aurothiomalate (GSTM) (either 5 micrograms/ml or 100 micrograms/ml). D-penicillamine (100 micrograms/ml) and dexamethasone (either 100 nM or 200 nM) did not reduce collagenase levels. Chloroquine (0.5 micrograms/ml) had a variable effect. Dexamethasone increased tissue inhibitor of metalloproteinases levels and also reduced collagenase levels in primary chondrocyte and cartilage fragment cultures. When the drugs were added to the mononuclear cells in culture, dexamethasone (10 nM), D-penicillamine (100 micrograms/ml), D-penicillamine (100 micrograms/ml) and copper sulphate (2 micrograms/ml) and chloroquine (5 micrograms/ml) reduced the activity of the conditioned medium when tested onchondrocytes. GSTM (100 micrograms/ml) and chloroquine (0.5 micrograms/ml) had no effect.

Anti-Inflammatory Agents↗
PubMed1980

Cutaneous biometrics I. The response of human skin to dimethyl sulphoxide.

The wealing response of human skin to dimethyl sulphoxide (DMSO) has been quantified. Concentrations of 90%, 95% and 100% were applied for 5 min circular areas 8 min in diameter. Wealing was scored on a five-point scale after 10 min. Marked individual variations were found. Wealing was strongly influenced by body region and was dose-dependent. The intensity of the reaction paralleled that to other irritants and was dependent mainly on thickness and integrity of the horny layer. The DMSO test is a simple, quick way to assess the barrier function of the stratum corneum.

Adolescent↗
PubMed1977

The action of progesterone and diethylstilboestrol on the dehydrogenase and esterase activities of a purified aldehyde dehydrogenase from rabbit liver.

A steroid-sensitive aldehyde dehydrogenase (EC 1.2.1.3) was purified from rabbit liver and is homogeneous by the criterion of electrophoresis in polyacrylamide gels with or without sodium dodecyl sulphate. The enzyme is tetrameric, of subunit mo.wt. 48 300, and contains no tightly bound zinc. The fluorescence of the protein is decreased in the presence of progesterone, which is inhibitory to the reactions catalysed by the enzyme. When NADH is bound to the enzyme, the fluorescence of the coenzyme is augmented to an extent independent of the presence of steroids or acetaldehyde. The purified enzyme catalyses the oxidation of acetaldehyde and glucuronolactone, and the hydrolysis of 4-nitrophenyl acetate. Each of these reactions is inhibited by progesterone in such a manner as to suggest the formation of a catalytically active enzyme-hormone complex. Diethylstilboestrol inhibits the hydrolysis of esters by this enzyme, but stimulates the oxidation of aldehydes, except at low aldehyde concentrations; the ligand is then inhibitory. NADH inhibits the hydrolysis of 4-nitrophenyl acetate by the enzyme in a partially competitive fashion.

Aldehyde Oxidoreductases↗
PubMed1976

A blood pressure clinic in a health centre.

Following a screening survey for hypertension in Renfrew, a blood pressure clinic was established in a health centre. Three hospital doctors, each working an average of two sessions weekly, saw 368 patients. A specially trained nurse played an important part in the running of the clinic. Attendance of patients was high, and defaulting amongst those needing treatment was low. Blood pressures were well controlled in 75% of the patients. The clinic has proved an acceptable method of managing large numbers of hypertensives without reference to hospital.

Community Health Centers↗