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M Cowen

Publications and source records attributed to M Cowen.

7 recordsLinked to original sources
PubMed2003

Validation of four different risk stratification systems in patients undergoing off-pump coronary artery bypass surgery: a UK multicentre analysis of 2223 patients.

BACKGROUND: Various risk stratification systems have been developed in coronary artery bypass graft surgery (CABG), based mainly on patients undergoing procedures with cardiopulmonary bypass. OBJECTIVE: To assess the validity and applicability of the Parsonnet score, the EuroSCORE, the American College of Cardiology/American Heart Association (ACC/AHA) system, and the UK CABG Bayes model in patients undergoing off-pump coronary artery bypass surgery (OPCAB) in the UK. METHODS: Data on 2223 patients who underwent OPCAB in eight cardiac surgical centres were collected. Predicted mortality risk scores were calculated using the four systems and compared with observed mortality. Calibration was assessed by the Hosmer-Lemeshow (HL) test. Discrimination was assessed using the receiver operating characteristic (ROC) curve area. RESULTS: 30 of 2223 patients (1.3%) died in hospital. For the Parsonnet score the HL test was significant (p < 0.001) and the receiver operating characteristic curve (ROC) area was 0.74. For the EuroSCORE the HL test was also significant (p = 0.008) and the ROC area was 0.75. For the ACC/AHA system the HL test was non-significant (p = 0.7) and the ROC area was 0.75. For the UK CABG Bayes model the HL test was also non-significant (p = 0.3) and the ROC area was 0.81. CONCLUSIONS: The UK CABG Bayes model is reasonably well calibrated and provides good discrimination when applied to OPCAB patients in the UK. Among the other three systems, the ACC/AHA system is well calibrated but its discrimination power was less than for the UK CABG Bayes model. These data suggest that the UK CABG Bayes model could be an appropriate risk stratification system to use for patients undergoing OPCAB in the UK.

Coronary Artery Bypass↗
PubMed2001

Association analysis of HTR6 and HTR2A polymorphisms in sporadic Alzheimer's disease.

In order to identify gene variants related to the serotonergic neurotransmitter system that possibly represent a hereditary risk factor for sporadic Alzheimer's disease (AD), patients suffering from AD and non-demented psychiatric inpatients without symptoms of dementia were genotyped for polymorphisms of HTR6 (267C/T) and HTR2A (-1438G/A). Although there was a tendency toward an increased number of the genotype TT of the 5-HT6 receptor polymorphism in AD patients when compared to controls (2.8% vs. 1.3%), neither this nor the 5-HT2A promoter polymorphism showed significant differences in their genotypic or allelic distribution among patients and controls. These polymorphisms probably do not represent major genetic risk factors of AD. However, further studies including other genetic variants of the serotonergic neurotransmitter system are needed in order to elucidate their role in AD.

Alleles↗
PubMed1998

Effects of acute ethanol on GABA release and GABA(A) receptor density in the rat mesolimbic system.

The present study has addressed whether acute ethanol administration mediates changes in GABA release and GABA(A) receptor density in the rat mesolimbic system. In vivo microdialysis was performed in the ventral pallidum and between the ventral tegmental area and substantia nigra of conscious ethanol-naive rats. Extracellular levels of endogenous GABA were stable in both brain regions and not significantly affected following administration of 5 ml of 20% ethanol by gavage, despite clear overt behavioral signs of intoxication. Two hours following ethanol administration, animals were decapitated and the brains processed for autoradiography. Adjacent tissue sections were incubated with [3H]SR95531 or [3H]muscimol and the resulting autoradiograms quantified. Binding of both radioligands was significantly reduced in the striatum of rats treated with ethanol compared to vehicle (15 +/- 2% for [3H]SR95531 and 33 +/- 6% for [3H]muscimol). In contrast, ethanol had no effect on [3H]SR95531 binding in hippocampus, while that of [3H]muscimol was increased by 100 +/- 30%. Ethanol had no effect on the binding of either radioligand in all other areas examined. Therefore, while acute ethanol had no effect on the release of GABA in either the ventral pallidum or ventral tegmental area, changes in the binding density of GABA(A) ligands were observed in selected brain regions.

Administration, Oral↗