[Clinical value of dual source computerized tomography in primary diagnosis of coronary heart disease]

Dual-source-CT-technology (DSCT) improves temporal resolution of cardiac computed tomography to 83 ms per heart-phase. In this study, the clinical performance of this new method is evaluated.

MATERIALS AND METHODS

In fifty patients (33 male, 17 female; age 50 +/- 13 years) with suspected coronary heart disease, CT angiography (slice thickness 0.75 mm, contrast-agent 60-80 ml iomeprol) was performed with a Somatom Definition scanner. Based on the coronary 15-segment-model of the AHA, scores for image quality and lumen reduction were established to enable the observer, to give recommendations for further therapy.

RESULTS

Out of 750 possible AHA-segments, 655 were depicted (87.3%). 591 segments (90.2%) were assessed without any limitation of quality, 49 (7.5%) segments showed moderate, and 15 (2.3%) segments severe limitation in image quality. 508 (77.6%) segments were without pathological findings, 92 (14.0%) segments had minimal atherosclerotic lesions, 42 (6.4%) segments suffered from stenoses with lumen reduction less than 70%, and 13 (2.0%) showed significant stenoses of more than 70%. In 31 patients (62%), coronary heart disease was ruled out by CT angiography without any need for further non-invasive or invasive diagnostics. 8 patients (16%) underwent stress-testing for ischemia. In 11 (22%) patients coronary angiography was recommended, and DSCT findings were confirmed in 10 cases. Only one LCx stenosis was overestimated in DSCT.

CONCLUSION

Contrast-enhanced DSCT is a powerful tool in diagnosis of coronary heart disease. 98% of coronary segments could be assessed in diagnostic quality, and at least 90% of haemodynamically significant coronary stenoses were detected.

Using a Bayesian method to assign individuals to karyotypic taxa in shrew hybrid zones

Individuals sampled in hybrid zones are usually analysed according to their sampling locality, morphology, behaviour or karyotype. But the increasing availability of genetic information more and more favours its use for individual sorting purposes and numerous assignment methods based on the genetic composition of individuals have been developed. The shrews of the Sorex araneus group offer good opportunities to test the genetic assignment on individuals identified by their karyotype. Here we explored the potential and efficiency of a Bayesian assignment method combined or not with a reference dataset to study admixture and individual assignment in the difficult context of two hybrid zones between karyotypic species of the Sorex araneus group. As a whole, we assigned more than 80% of the individuals to their respective karyotypic categories (i.e. 'pure' species or hybrids). This assignment level is comparable to what was obtained for the same species away from hybrid zones. Additionally, we showed that the assignment result for several individuals was strongly affected by the inclusion or not of a reference dataset. This highlights the importance of such comparisons when analysing hybrid zones. Finally, differences between the admixture levels detected in both hybrid zones support the hypothesis of an impact of chromosomal rearrangements on gene flow.

Identification and characterization of Cor33p, a novel protein implicated in tolerance towards oxidative stress in Candida albicans

We applied two-dimensional gel electrophoresis to identify downstream effectors of CPH1 and EFG1 under hypha-inducing conditions in Candida albicans. Among the proteins that were expressed in wild-type cells but were strongly downregulated in a cph1Delta/efg1Delta double mutant in alpha-minimal essential medium at 37 degrees C, we could identify not-yet-characterized proteins, including Cor33-1p and Cor33-2p. The two proteins are almost identical (97% identity) and represent products of allelic isoforms of the same gene. Cor33p is highly similar to Cip1p from Candida sp. but lacks any significant homology to proteins from Saccharomyces cerevisiae. Strikingly, both proteins share homology with phenylcoumaran benzylic ether reductases and isoflavone reductases from plants. For other hypha-inducing media, like yeast-peptone-dextrose (YPD) plus serum at 37 degrees C, we could not detect any transcription for COR33 in wild-type cells, indicating that Cor33p is not hypha specific. In contrast, we found a strong induction for COR33 when cells were treated with 5 mM hydrogen peroxide. However, under oxidative conditions, transcription of COR33 was not dependent on EFG1, indicating that other regulatory factors are involved. In fact, upregulation depends on CAP1 at least, as transcript levels were clearly reduced in a Deltacap1 mutant strain under oxidative conditions. Unlike in wild-type cells, transcription of COR33 in a tsa1Delta mutant can be induced by treatment with 0.1 mM hydrogen peroxide. This suggests a functional link between COR33 and thiol-specific antioxidant-like proteins that are important in the oxidative-stress response in yeasts. Concordantly, cor33Delta deletion mutants show retarded growth on YPD plates supplemented with hydrogen peroxide, indicating that COR33 in general is implicated in conferring tolerance toward oxidative stress on Candida albicans.

[Nightmares in patients with Alzheimer's disease caused by donepezil. Therapeutic effect depends on the time of intake]

Dementia of the Alzheimer type (DAT) has been linked to losses of cholinergic function in the brain. The acetylcholinesterase inhibitors donepezil, rivastigmine and galantamine improve cognitive performance in manifest dementia. These substances, however, also influence the quality of sleep, and particularly the quality and amount of dreams. We therefore investigated the influence of the time point of donepezil intake on the occurrence of nightmares. We observed a clear-cut relationship between the occurrence of nightmares and an evening dose of donepezil in eight patients with DAT. None of these patients reported nightmares when donepezil was taken in the morning. We suggest that the activation of the visual association cortex during REM sleep is enhanced by donepezil, a mechanism most likely facilitating the development of nightmares in patients with DAT.