Tauchunfälle

Notfall + Rettungsmedizin - Tauchunfälle sind vergleichsweise selten und stellen (Erst‑)Helfer vor besondere Herausforderungen. Sie müssen schnell und kompetent behandelt werden, da...     

Continuously moving table 3D MRI with lateral frequency-encoding direction.

A method is presented for 3D MRI in an extended field of view (FOV) based on continuous motion of the patient table and an efficient acquisition scheme. A gradient-echo MR pulse sequence is applied with lateral (left-right (L/R)) frequency-encoding direction and slab selection along the direction of motion. Compensation for the table motion is achieved by a combination of slab tracking and data alignment in hybrid space. The method allows fast k-space coverage to be achieved, especially when a short sampling FOV is chosen along the direction of table motion, as is desirable for good image quality. The method can be incorporated into different acquisitions schemes, including segmented k-space scanning, which allows for contrast variation with the use of magnetization preparation. Head-to-toe images of volunteers were obtained with good quality using 3D spoiled gradient-echo sequences. As an example of magnetization-prepared imaging, fat/water separated images were acquired using chemical shift selective (CHESS) presaturation pulses.     

Comparative early and midterm results of open juxtarenal and infrarenal aneurysm repair

Background and aims Since the introduction of endovascular aortic aneurysm repair (EVAR) for aortic aneurysms, the number of juxtarenal aortic aneurysms (JRA) has been growing steadily due to selection bias (neck morphology for EVAR). This case-match study compares the perioperative outcome and midterm results of suprarenally clamped JRA with infrarenal aortic aneurysms (AAA). Methods From 1997 to 2004, patients who received open surgery with suprarenal clamping for JRA were included in the study and compared to matched patients with infrarenal clamping (AAA). Measurements analyzed were the in-hospital mortality and morbidity. Midterm results were obtained through clinical investigation and magnetic resonance angiography imaging. Results Thirty-five patients (mean age, 68.4 years; 30 male and 5 female) received suprarenal cross-clamping for JRA. The overall in-hospital mortality for JRA and for the controls (AAA) with elective aortic repair was 4.5% (6.1% JRA; 3% AAA, p = 0.058). The morbidity of JRA was elevated according to the rate of pulmonary complications (p = 0.021) and the need for re-operation (p = 0.019). The mean follow-up time was 2.3 years (range, 8–96 months). At follow-up, 28 patients (80%) from the JRA group and 29 patients from the AAA group (82.9%) were alive. Conclusion Open aortic surgery for JRA with the need for suprarenal cross-clamping shows a slightly elevated in-hospital mortality rate without statistical significance and equal midterm mortality results in comparison with infrarenally clamped aortic aneurysms.     

Imaging of activated microglia with PET and [11C]PK 11195 in corticobasal degeneration.

Positron emission tomography (PET) using [(11)C]PK 11195, a ligand for peripheral benzodiazepine receptor binding sites, offers the opportunity to image activated microglia in vivo. This tool may therefore be used to display the occurrence of microglial activation in the course of neurodegeneration. A patient with the clinical diagnosis of corticobasal degeneration (CBD) and left-sided symptoms was studied using fluorodeoxyglucose (FDG) and [(11)C]PK 11195 PET. We found a marked right hemispheric hypometabolism and asymmetric microglial activation in corresponding areas of the basal ganglia and right temporal and parietal cortex. [(11)C]PK 11195 PET suggests involvement of microglial activation in the pathogenesis of CBD.     

Untersuchungen an 1,4-Napthochinonen, 24. Mitt.: Zur Dehalogenierung von 2-/3-Halogen-1,4-naphthochinon-derivaten

1,4-Naphthoquinones, XXIV: On the Dehalogenation of 2-/3-Halogen-1,4-naphthoquinone Derivatives Bu₃SnH is an effective reagent for the debromination of 2-bromonaphthoquinones but elimination of chlorine with 1c , e.g., only proceeds at 30%. With Et₃SiH dechlorination does not occur at all. Instead, with the 5-acetoxy derivatives 1a/1d as starting materials the cyclic acetales 3a – c are formed as selectively protected juglone derivatives. The bromo derivative 3a is obtained only at temp. < 10° and even at room temp. Br-Elimination occurs with low yield of 3b . An especially suitable reagent for the debromination of 1a – b leading to the natural compounds plumbagin ( 2a ) and isoplumbagin ( 2b ) is zinc-silver couple but Cl-elimination again occurs in traces only.