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Mit der Computertomographie (CT) konnen Thromben im linken Vorhofohr (LAA) dargestellt werden. Es wurde untersucht, ob sich die diagnostische Genauigkeit durch die Dual-Energy-Technik im Vergleich zur transosophagealen Echokardiographie (TEE) verbessert. Weiterhin wurde der Einfluss von Protokollparametern auf die Strahlendosis quantifiziert. Die TEE-Patienten wurden den verschiedenen CT-Protokollen zugeordnet. Alle CTs wurden auf das Vorhandensein von LAA-Thromben und Dual-Energy-CT-Scans sowie zusatzlich quantitativ auf die Jodkonzentration analysiert. Die TEE wurde qualitativ auf das Vorhandensein von Thromben untersucht. Von Insgesamt 32 eingeschlossenen Patienten hatten 6 einen mittels TTE diagnostizierten Thrombus. Die qualitative CT-Beurteilung ergab eine Sensitivitat von 83 % und eine Spezifitat von 88 % fur die LAA-Thrombus-Detektion. Bei 26 Patienten wurde eine Dual-Energy-CT durchgefuhrt. Die mittlere Jodkonzentration betrug 8,6 mg/cm3 und war bei Patienten mit LAA-Thromben signifikant niedriger als bei Patienten ohne LAA-Thromben. Ferner ergab sich ein inkrementeller Wert fur die Erkennung von LAA-Thromben (AUC: 0,950 vs. 0,867 bei kombinierter vs. nur qualitativer Beurteilung; p = 0,04). Die mediane Strahlendosis betrug 1,83 mSv. Unabhangig voneinander war die Dosis bei Beschrankung des Scanabschnitts auf den LAA und beim prospektiven Gating niedriger, wahrend Arrhythmie und Dual-Energy-Technik die Strahlendosis nicht beeinflussten. Die CT bietet eine gute diagnostische Genauigkeit fur den Nachweis von LAA-Thromben, die durch Joddichtemessung mittels Dual-Energy-CT noch weiter verbessert werden kann. Mit einem optimierten Protokoll kann eine angemessen niedrige Strahlendosis erreicht werden.

Contrast-enhanced computed tomography (CT) is a convenient method to visualize left atrial appendage (LAA) thrombi. We determined whether diagnostic accuracy improves by including dual-energy as compared to transesophageal echocardiography (TEE). Furthermore, the influence of protocol parameters on radiation dose were quantified.Patients were assigned to the different CT protocols. All CTs were assessed qualitatively for presence of LAA thrombi and dual-energy CT scans quantitatively for iodine concentration. TEE was assessed qualitatively for the presence of thrombi.Of 32 enrolled patients, 6 had a thrombus in TEE. Qualitative CT assessment yielded 83% sensitivity and 88% specificity. In the 26 patients who underwent dual-energy CT, median iodine concentration was 8.6 mg/cmCT provides good diagnostic accuracy for detecting LAA thrombi, which can further be improved if iodine density measurements by dual-energy are incorporated. With an optimized protocol, reasonably low radiation dose can be achieved.

The aim of this study was to determine the effects of alpha-ketoglutarate on neutrophil (PMN), free alpha-keto and amino-acid profiles as well as important reactive oxygen species (ROS) produced [superoxide anion (O(2) (-)), hydrogen peroxide (H(2)O(2))] and released myeloperoxidase (MPO) activity. Exogenous alpha-ketoglutarate significantly increased PMN alpha-ketoglutarate, pyruvate, asparagine, glutamine, asparatate, glutamate, arginine, citrulline, alanine, glycine and serine in a dose as well as duration of exposure dependent manner. Additionally, in parallel with intracellular alpha-ketoglutarate changes, increases in O(2) (-) formation, H(2)O(2)-generation and MPO activity have also been observed. We therefore believe that alpha-ketoglutarate is important for affecting PMN "susceptible free amino- and alpha-keto acid pools" although important mechanisms and backgrounds are not yet completely explored. Moreover, our results also show very clearly that changes in intragranulocytic alpha-ketoglutarate levels are relevant metabolic determinants in PMN nutrition considerably influencing and modulating the magnitude and quality of the granulocytic host defense capability as well as production of ROS.

Procedures for the analysis of free alpha-keto acids in human fluids (i.e. plasma, cerebrospinal fluid, urine, etc.) as well as for studying the dynamic free alpha-keto acid pools in differentiated tissues and organ cells have been the subject of growing clinical interest in the study of metabolic regulatory and pathophysiological phenomena. Due to the high instability and polarity of the alpha-keto acids being examined, the development of a quantitative and reproducible analysis of metabolically relevant intracellular alpha-keto acids still presents a substantial methodological challenge. The aim of small sample size, rapid, non-damaging and "metabolism-neutral" cell isolation, careful sample preparation and stability, as well as reproducible analytics technology is not often achieved. Only few of the methods described can satisfy the rigorous demands for an ultra-sensitive, comprehensive and rapid intracellular alpha-keto acid analysis.

We examined the effects of beta-alanine (taurine analogue and taurine transport antagonist), taurine (regarding its role in neutrophil (PMN) immunonutrition) and taurine combined either with L-NAME (inhibitor of *NO-synthase), SNAP (*NO donor), DON (glutamine-analogue and inhibitor of glutamine-requiring enzymes), DFMO (inhibitor of ornithine-decarboxylase) and beta-alanine on neutrophil amino- and alpha-keto acid profiles or important PMN immune functions in order to establish whether taurine transport-, nitric oxide-, glutamine- or ornithine-dependent mechanisms are involved in any of the taurine-induced effects. According to the present findings, the taurine-mediated effect appears to be based primarily on a modulation of important transmembraneous transport mechanisms and only secondarily on directly or indirectly induced modifications in intragranulocytic amino- and alpha-keto acid homoeostasis or metabolism. Although a direct relation to the parallel observed immunological modifications can only be presumed, these results show very clearly that compositional modifications in the free intragranulocytic amino- and alpha keto-acid pools coinciding with changes in intragranulocytic taurine levels are relevant metabolic determinants that can significantly influence the magnitude and quality of the granulocytic immune response.