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Biomedical subjects

K A Chalmers

Publications and source records attributed to K A Chalmers.

6 recordsLinked to original sources
PubMed2001

Selective small-molecule inhibitors of glycogen synthase kinase-3 activity protect primary neurones from death.

The phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B (PKB; also known as Akt) signalling pathway is recognized as playing a central role in the survival of diverse cell types. Glycogen synthase kinase-3 (GSK-3) is a ubiquitously expressed serine/threonine protein kinase that is one of several known substrates of PKB. PKB phosphorylates GSK-3 in response to insulin and growth factors, which inhibits GSK-3 activity and leads to the modulation of multiple GSK-3 regulated cellular processes. We show that the novel potent and selective small-molecule inhibitors of GSK-3; SB-415286 and SB-216763, protect both central and peripheral nervous system neurones in culture from death induced by reduced PI 3-kinase pathway activity. The inhibition of neuronal death mediated by these compounds correlated with inhibition of GSK-3 activity and modulation of GSK-3 substrates tau and beta-catenin. Thus, in addition to the previously assigned roles of GSK-3, our data provide clear pharmacological and biochemical evidence that selective inhibition of the endogenous pool of GSK-3 activity in primary neurones is sufficient to prevent death, implicating GSK-3 as a physiologically relevant principal regulatory target of the PI 3-kinase/PKB neuronal survival pathway.

Aminophenols↗
PubMed2000

Dual processes in recognition: does a focus on measurement operations provide a sufficient foundation?

Current theoretical thinking about dual processes in recognition relies heavily on the measurement operations embodied within the process dissociation procedure. We critically evaluate the ability of this procedure to support this theoretical enterprise. We show that there are alternative processes that would produce a rough invariance in familiarity (a key prediction of the dual-processing approach) and that the process dissociation procedure does not have the power to differentiate between these alternative possibilities. We also show that attempts to relate parameters estimated by the process dissociation procedure to subjective reports (remember-know judgments) cannot differentiate between alternative dual-processing models and that there are problems with some of the historical evidence and with obtaining converging evidence. Our conclusion is that more specific theories incorporating ideas about representation and process are required.

Choice Behavior↗
PubMed1997

A naturalistic study of the word frequency effect in episodic recognition.

In order to separate the effects of experience from other characteristics of word frequency (e.g., orthographic distinctiveness), computer science and psychology students rated their experience with computer science technical items and nontechnical items from a wide range of word frequencies prior to being tested for recognition memory of the rated items. For nontechnical items, there was a curvilinear relationship between recognition accuracy and word frequency for both groups of students. The usual superiority of low-frequency words was demonstrated and high-frequency words were recognized least well. For technical items, a similar curvilinear relationship was evident for the psychology students, but for the computer science students, recognition accuracy was inversely related to word frequency. The ratings data showed that subjective experience rather than background word frequency was the better predictor of recognition accuracy.

Adult↗
PubMedDate not supplied

Psychometric properties of a quitting time for alcohol questionnaire: factor structure, reliability, and validity.

Research into the dynamics of alcohol use has traditionally focused on etiological factors, particularly on the reasons an individual engages in drinking behaviours. Although reasons for the permanent cessation of drinking have also been well documented, little is known about the reasons for the episodic cessation of alcohol use that is characteristic of nonproblematic drinking patterns. The purpose of the present study was to develop and validate a questionnaire designed to monitor the reasons an individual temporarily stops drinking at the end of a drinking episode. A 23-item Quitting Time for Alcohol Questionnaire (QTAQ) was developed and distributed to a community based sample of 252 participants. Factor analysis revealed three conceptually distinct factors, QTAQ-IS (Internal Status) QTAQ-AA (Avoidance Adherence) and QTAQ-IC (Immediate Context), which accounted for 36.3% of the variance. Cross-validation on a large sample of undergraduate students (N = 479) confirmed the three-factor solution (accounting for 33% of the variance). Cronbach's alpha coefficients for the factors ranged from .74 to .81 for the community sample and from .62 to .78 for the student sample. The validity of the emergent factors was demonstrated by their ability to classify participants according to self-reported alcohol consumption and alcohol dependence criteria, and also by their significant predictive relationship with these criteria. The present findings suggest that the QTAQ is a useful instrument both for research and for use in clinical practice.

Adolescent↗