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Biomedical subjects

G T Payne

Publications and source records attributed to G T Payne.

5 recordsLinked to original sources
PubMed2001

An integrated doctoral educational model for developing researchers in health care strategic management.

Doctoral education varies according to how students that graduate from a particular program are prepared for various type of careers. PhD programs principally work to develop researchers; researchers produce and disseminate new knowledge in a given area of expertise. This manuscript looks specifically at a PhD program designed to produce researchers in healthcare strategic management. This program is based in a business school and builds on general business principles to produce strategists that do research in the healthcare context. The business school program (type B) will be analyzed according to the areas (or potential areas) of research done by its graduates. The different areas are shown in a table where one axis is research content (i.e., specifically what the functional area of research is) and the other axis is publication outlet (i.e., what journal the research is disseminated in). Advantages of the type B program are compared to advantages of a PhD program based in a healthcare administration or healthcare management school (type H program) in terms of publications in these different areas.

Curriculum↗
PubMed2000

The paradox prescription: leading the medical group of the future.

Leaders of health care organizations must constantly deal with paradox in and around their organizations. The paradox profile is a modeling technique for examining how organizations prioritize their dealings with the eight competing issues from which the four paradoxes are derived. This article demonstrates the leadership challenges that exist when a paradox is present and how these tensions differ when the integrative status of the medical group--as either part of an integrated system or not--is considered.

Conflict, Psychological↗
PubMed1991

Activation of gamma-aminobutyric acid insensitive chloride channels in mouse brain synaptic vesicles by avermectin B1a.

The interaction of avermectin B1a (AVMB1a) with mouse brain chloride channels was characterized using a radiochloride efflux assay. The loss of intravesicular chloride from synaptoneurosomes preloaded with 36Cl involved an initial rapid phase followed by a slower phase that approached equilibrium within 10 min. AVMB1a stimulated a 30% loss of intravesicular chloride within the first 2 s of exposure; however, AVMB1a had no effect on the rate of the slower phase of chloride loss. Experiments with lysed synaptoneurosomes showed that both chloride loading and basal and AVMB1a-stimulated chloride release required the presence of intact vesicles. The efflux of 36Cl from mouse brain synaptosomes and the stimulation of efflux by AVMB1a were qualitatively similar to the results obtained with synaptoneurosomes but involved much lower overall levels of chloride loading and release. AVMB1a produced half-maximal stimulation of chloride efflux from synaptoneurosomes at a concentration of 2.1 +/- 0.3 microM and a 35.4 +/- 1.4% maximal loss of intravesicular chloride at saturating concentrations. gamma-Aminobutyric acid (GABA), bicuculline, or the chloride channel blockers picrotoxinin, t-butylbicyclophosphorothionate (TBPS) 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), and anthracene 9-carboxylic acid (9-CA) had little or no effect on the loss of chloride from synaptoneurosomes either in the presence or the absence of AVMB1a. However, the chlorinated cycloalkane insecticides dieldrin and lindane were equally effective as inhibitors of GABA-dependent chloride uptake and AVMB1a-stimulated chloride efflux. These data demonstrate that AVMB1a-stimulated chloride efflux from mouse brain synaptic vesicles results from the activation of GABA-insensitive chloride channels and that this action is distinct from their previously documented effects on GABA-gated chloride channels in mouse brain preparations. Our findings imply that both GABA-gated and GABA-insensitive chloride channels may be toxicologically significant targets for the action of avermectins.

Animals↗
PubMed1989

Activation of sodium channels and inhibition of [3H]batrachotoxinin A-20-alpha-benzoate binding by an N-alkylamide neurotoxin.

BTG 502 [(2E,4E)-N-(1,2-dimethyl)-propyl-6-(5-bromonaphth-2-yl)-hexa -2,4- dienamide], a synthetic analog of insecticidal amides isolated from Piper species, stimulated 22Na+ uptake into mouse brain synaptoneurosomes in the presence of saturating concentrations of Leiurus quinquestriatus venom but had no effect on sodium uptake in the absence of venom. In the presence of Leiurus venom, half-maximal stimulation was achieved at a BTG 502 concentration of 1.7 microM, whereas maximal stimulation (2.3-fold greater than nonspecific uptake) was observed at 50 microM. In the absence of other modifiers, BTG 502 inhibited batrachotoxin (BTX)-dependent sodium uptake, producing 50% inhibition at 2 microM. In the presence of Leiurus venom, BTG 502 was a partial inhibitor of BTX-dependent 22Na+ uptake, producing half-maximal inhibition at 1.5 microM. The levels of residual BTX-dependent sodium uptake and maximal BTG 502-dependent sodium uptake measured in the presence of Leiurus venom were identical. BTG 502 inhibited the specific binding of [3H]batrachotoxinin A-20-alpha-benzoate (BTX-B) to the activator recognition site (site 2) of sodium channels in these preparations, producing half-maximal inhibition at 2 microM and maximal inhibition at 30 microM. Equilibrium analysis showed that BTG 502 was an apparent competitive inhibitor of [3H]BTX-B binding, producing a concentration-dependent decrease in the affinity of sodium channels for this ligand without affecting binding capacity. Kinetic analysis demonstrated that BTG 502 slowed the rate of formation of the ligand-receptor complex but did not alter the rate of dissociation of this complex. The effects of BTG 502 on 22Na+ uptake and [3H]BTX-B binding are consistent with the action of this compound as an antagonist at the activator recognition site of the voltage-sensitive sodium channel in the absence of Leiurus venom and as a partial agonist at this site in the presence of Leiurus venom. These results suggest that the N-alkylamides represent a novel chemical class of neurotoxins that act at site 2 of the sodium channel.

Animals↗