COMT Val 158 Met polymorphism is associated with cognitive flexibility in a signal discrimination task in schizophrenia

BACKGROUND

Associations between the well-known functional single nucleotide polymorphism Val (158)Met in the gene encoding catechol- O-methyltransferase (COMT) and cognitive do-mains affected in schizophrenia are inconsistent regarding directionality and specific impact and call for a more fundamental cognitive endophenotype. Recent studies suggest that the COMT genotype contributes to cognitive flexibility, a fundamental cognitive ability that potentially influences an individual's performance in a variety of other neurocognitive tasks.

METHODS

We investigated the association between COMT Val (158)Met genotype and cognitive flexibility as assessed by signal discrimination in the Continuous Performance Test - Identical Pairs version in a cohort of 111 German schizophrenic patients.

RESULTS

COMT genotype was significantly associated with signal discrimination index d' in schizophrenia. The Val/Val genotype was associated with the highest and the Met/Met genotype with the lowest scores; heterozygous individuals displayed an intermediate performance.

CONCLUSIONS

Our data suggest that allelic variation at the COMT Val (158)Met locus may influence signal discrimination capacity in schizophrenia and confirm that Val loading, probably due to decreased prefrontal dopamine availability, is associated with greater cognitive flexibility, which in turn may influence other cognitive measures that have been associated with COMT to date.

[E-learning about dementia: a randomized study]

BACKGROUND

Curricular medical training on dementia at the Department of Psychiatry and Psychotherapy at the University of Erlangen comprises of a traditional lecture. This setting was compared with two different E-Learning formats using a randomized study design.

METHODS

104 students (average age 26.3 +/- 3.6 years) were randomized into 3 groups: Interactive e-Learning; virtual lecture (slides and audio) and standard lecture (control group; 90 minutes).

RESULTS

Overall, the response rate was 40.4 %. Assessment of formal knowledge using a multiple-choice test yielded no differences between the three groups. In the students' evaluation, the interactive e-learning showed the best results (1.86 +/- 0.69), followed by the standard lecture (2.0 +/- 0.71) and the virtual lecture (2.6 +/- 0.8). Nevertheless, the students would not prefer e-learning to the standard lecture when both methods are directly compared.

CONCLUSION

Our findings suggest that e-learning is equivalent to a standard lecture when formal knowledge is assessed. Evaluation results are best for interactive e-learning formats. The detailed reasons for the preference of different learning styles should be further investigated.

Stable Cognition After Coronary Artery Bypass Grafting: Comparisons With Percutaneous Intervention and Normal Controls

BACKGROUND

Cognitive decline has been associated with coronary artery bypass grafting (CABG), but the extent to which these findings are related to the natural history of cognitive deficits in elderly patients with cardiac disease or have been influenced by the research methods used to determine abnormalities warrants further study.

METHODS

After excluding individuals with conditions known to cause brain dysfunction, individuals referred for percutaneous coronary intervention (n = 42) or CABG (n = 35) were compared with an age-matched and education-matched control group without clinical evidence of coronary artery disease (n = 44). These subjects underwent a battery of 14 neurocognitive tests at baseline (preoperatively) and at 3 weeks and 4 months postoperatively.

RESULTS

The majority of test scores for all three cohorts were within nonimpaired ranges at baseline and 3 weeks later. Change in impairment status from baseline to 3-week assessment was not associated statistically with type of treatment as referenced to clinical norms, and was associated with type of treatment on only one measure as referenced to control group performances. A further overall improvement in impairment status from 3 weeks' to 4 months' follow-up was seen in both CABG and percutaneous coronary intervention patients. Mean test scores were significantly worse in CABG patients versus percutaneous coronary intervention patients in 4 of 13 measures at 3 weeks' follow-up, but significant de novo impairment at 3 weeks' follow-up in the CABG group compared with the percutaneous coronary intervention and control groups was present in only one test. As assessed by reliable change methodology, impairment was statistically associated with type of treatment for only 1 of 13 measures.

CONCLUSIONS

As compared with changes seen in repeat testing of healthy control subjects and individuals who underwent percutaneous coronary intervention, clinically meaningful cognitive deterioration was not observed after CABG.

GRAMA: genetic mapping analysis of temperature gradient capillary electrophoresis data

Temperature gradient capillary electrophoresis (TGCE) is a high-throughput method to detect segregating single nucleotide polymorphisms and InDel polymorphisms in genetic mapping populations. Existing software that analyzes TGCE data was, however, designed for mutation analysis rather than genetic mapping. Genetic recombinant analysis and mapping assistant (GRAMA) is a new tool that automates TGCE data analysis for the purpose of genetic mapping. Data from multiple TGCE runs are analyzed, integrated, and displayed in an intuitive visual format. GRAMA includes an algorithm to detect peaks in electropherograms and can automatically compare its peak calls with those produced by another software package. Consequently, GRAMA provides highly accurate results with a low false positive rate of 5.9% and an even lower false negative rate of 1.3%. Because of its accuracy and intuitive interface, GRAMA boosts user productivity more than twofold relative to previous manual methods of scoring TGCE data. GRAMA is written in Java and is freely available at http://www.complex.iastate.edu .

Cross linking to tissue transglutaminase and collagen favours gliadin toxicity in coeliac disease

BACKGROUND AND AIMS

Intestinal inflammation in coeliac disease is driven by the gluten fraction of wheat proteins. Deamidation or cross linking of gluten peptides by tissue transglutaminase (tTG), the coeliac disease autoantigen, creates potent T cell stimulatory peptides. Therefore, our aim was to identify the reaction patterns of gluten peptides, intestinal extracellular matrix proteins, and tTG.

METHODS

tTG activity was analysed by incorporation of monodansyl cadaverine into gliadins. Fluorescence labelled tTG reactive short gliadin peptides were used to demonstrate their deamidation and explore their cross linking patterns with tTG itself or extracellular matrix proteins. Patient sera and controls were checked for autoantibodies to matrix proteins.

RESULTS

Gliadins alpha1-alpha11, gamma1-gamma6, omega1-omega3, and omega5 were substrates for tTG. tTG catalysed the cross linking of gliadin peptides with interstitial collagen types I, III, and VI. Coeliac patients showed increased antibody titres against the collagens I, III, V, and VI.

CONCLUSIONS

tTG formed high molecular weight complexes with all tested gliadins. As all tested gliadins were substrates for tTG, the tTG catalysed modifications were not restricted to single gliadin types and epitopes. Furthermore, haptenisation and long term immobilisation of gliadin peptides by tTG catalysed binding to abundant extracellular matrix proteins could be instrumental in the perpetuation of intestinal inflammation and some associated autoimmune diseases in coeliac disease.

Neurocognitive Functioning in Patients Undergoing Coronary Artery Bypass Graft Surgery or Percutaneous Coronary Intervention: Evidence of Impairment Before Intervention Compared With Normal Controls

BACKGROUND

Cognitive deficits have been reported to occur in a significant proportion of patients undergoing coronary artery bypass grafting (CABG), but the extent to which these deficits were preexistent or related to the natural history of cognitive decline in this patient population remains poorly defined.

METHODS

After excluding patients with conditions known to cause brain dysfunction (eg, hepatic dysfunction, stroke), a group of patients referred for percutaneous coronary intervention (PCI) or CABG (n = 82) was compared with an age- and education-matched control group that did not have clinical evidence of coronary artery disease (n = 41). These subjects underwent a battery of neurocognitive and emotional testing.

RESULTS

Test score means for 5 of 14 different measures were significantly greater (impaired) in cardiac compared with control group subjects. Of cardiac subjects, 20% demonstrated clinical impairment (test result > or = 1 SD worse than mean for normative standards) in 6 of 14 tests, compared with 10% of the controls. By clinical standards, 46% of cardiac subjects would be considered to be impaired (score 1 SD or more below the control group mean) on 3 or more neuropsychologic measures, compared with 29% of the controls. By this (control group mean) standard, cardiac subjects demonstrated impaired scores on 3.06 +/- 2.6 tests compared with impairment in 2.0 +/- 2.35 tests for the control group (p = 0.01).

CONCLUSIONS

Even excluding patients at high risk for brain dysfunction, cognitive impairment is found in patients with coronary artery disease before interventional therapy. Baseline impairment must be considered when evaluating outcomes after intervention.