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Zeitschriften

Ohne Zusammenfassung     

Zeitschriften

Ohne Zusammenfassung     

Zeitschriften

Ohne Zusammenfassung     

Value and consequences of routine intraoperative cholangiography during cholecystectomy

Since the introduction of laparoscopic cholecystectomy (LC), an increase in accidental common bile duct (CBD) injuries of up to 1.2-1.6% has been reported. In the present prospective study of 1,710 patients undergoing cholecystectomy (1,241 LC procedures and 469 open cholecystectomies [OC]), we tested the predicative value of routine intraoperative cholangiography (IOC). The IOC was feasible in 92.4% of the cases in the LC group and in 83% of cases in the OC group and presented a complete depiction of the extrahepatic bile system in 98.3%. Anatomic variations of the bile duct system, which influenced the operative management, were found in 13.2% of cases (13.4% LC versus 12.8% OC). In 2.5% of the patients, preoperatively undetected CBD stones were also found. Method-specific complications did not occur in any of the patients. Additionally, in a controlled subgroup analysis of 163 patients, we evaluated preoperative intravenous cholangiography (IVC) and IOC. Intravenous cholangiography showed only 72.4% of the operation-relevant anatomic variations (vs. 100% by IOC); in 6.1% of the cases, there were reactions to the dye (vs. none in IOC), and in only 28.6% of the patients, CBD stones were detected (vs. 71.4% IOC). There were four bile duct injuries (0.29%) during LC and two (0.4%) during OC. All injuries were detected intraoperatively and fixed in the same setting without postoperative complications. In conclusion, we recommend the use of routine IOC during cholecystectomy. By this technique, anatomic variations of the bile duct system will be visualized and therefore accidental injuries will be avoided.     

Comparison of aortic root replacement in patients with Marfan syndrome

Objectives: Although the aortic-valve-sparing (AVS) reimplantation technique according to David has shown favorable durability results in mid-term and long-term studies, composite valve grafting (CVG) according to Bentall is still considered the standard procedure. Methods: Retrospectively, we evaluated the results of aortic root replacement of patients with Marfan syndrome (MFS) who underwent surgery between January 1995 and January 2010. MFS was diagnosed using the Ghent criteria. AVS was used in 58 patients and CVG in 30 patients with MFS. AVS was done for aortic-root aneurysm (n = 48) or aortic dissection type A (n = 10). CVG was used for aortic-root aneurysm in 14 patients or aortic dissection type A in 16 patients. The mean follow-up was 3.2 (95% CI: 2.4–4.2) years. Results: In both groups, 30-day mortality was 0%. Three patients (10.0%) in the CVG group required resternotomy for postoperative bleeding versus two patients (3.4%) in the AVS group (p = 0.3). At follow-up, mortality was 10% in the CVG group versus 3.4% in the AVS group (p = 0.3). Re-operation was required in two patients (3.4%) after AVS and in three patients after CVG (10%) (p = 0.3). Three patients (10.0%) who underwent CVG had endocarditis and two patients (6.7%) had a stroke during follow-up, whereas no endocarditis and stroke occurred after AVS. After 14 years, stratified event-free survival was better in the AVS group (event-free survival was 82.3% vs 58.6%, log-rank test p = 0.086), especially after aneurysm (p = 0.057). After 10 years, freedom from aortic regurgitation ≥II° in the AVS group was 80% for aneurysm and 50% after dissection (p = 0.524). Conclusion: The reimplantation technique according to David was associated with excellent survival, good valve function and a low rate of re-operation, endocarditis, and stroke. There was a trend to better event-free survival for AVS patients making it the procedure of choice in MFS patients.     

Does experience predict observational kinematic assessment accuracy?

Observation of patients' movements forms an integral part of the development of therapeutic treatment plans for neurological patients. In this study we investigated the influence of clinical experience on the accuracy of observational kinematic assessment (OKA) of upper limb movements. Twenty-one physiotherapists and 15 students participated. The less experienced (LE) group ( n = 11) had a mean of 2.8 years ( &#45 1.8 years) of clinical experience and the highly experienced (HE) group ( n = 10) had a mean of 10.5 years ( &#45 2.2 years) of experience. The novice group (N) consisted of students in the third year of their Physiotherapy degree. Highly experienced, LE, and N participants observed the videotaped movements of healthy and neurologically impaired performers and made visual judgments about the speed, jerkiness, and path indirectness of performances, recording their judgments on visual analogue scales. We compared observers' judgments with kinematic indices derived from three-dimensional computer-assisted motion analysis to determine OKA accuracy. All groups of observers made moderate to highly accurate judgments with no significant differences between groups. Furthermore, inter-rater reliability was not experience-dependent. We discuss why experiential differences might be absent and provide suggestions for future development of OKA.     

Humans possess two mitochondrial ferredoxins,Fdx1 and Fdx2, with distinct roles in steroidogenesis,heme, and Fe/S cluster biosynthesis

Mammalian adrenodoxin (ferredoxin 1; Fdx1) is essential for the synthesis of various steroid hormones in adrenal glands. As a member of the [2Fe-2S] cluster-containing ferredoxin family, Fdx1 reduces mitochondrial cytochrome P450 enzymes, which then catalyze; e.g., the conversion of cholesterol to pregnenolone, aldosterone, and cortisol. The high protein sequence similarity between Fdx1 and its yeast adrenodoxin homologue (Yah1) suggested that Fdx1, like Yah1, may be involved in the biosynthesis of heme A and Fe/S clusters, two versatile and essential protein cofactors. Our study, employing RNAi technology to deplete human Fdx1, did not confirm this expectation. Instead, we identified a Fdx1-related mitochondrial protein, designated ferredoxin 2 (Fdx2) and found it to be essential for heme A and Fe/S protein biosynthesis. Unlike Fdx1, Fdx2 was unable to efficiently reduce mitochondrial cytochromes P450 and convert steroids, indicating that the two ferredoxin isoforms are highly specific for their substrates in distinct biochemical pathways. Moreover, Fdx2 deficiency had a severe impact, via impaired Fe/S protein biogenesis, on cellular iron homeostasis, leading to increased cellular iron uptake and iron accumulation in mitochondria. We conclude that mammals depend on two distinct mitochondrial ferredoxins for the specific production of either steroid hormones or heme A and Fe/S proteins.     

Response of human bone marrow stromal cells to a novel ultra-fine-grained and dispersion-strengthened titanium-based material

A novel titanium-based material, containing no toxic or expensive alloying elements, was compared to the established biomaterials: commercially pure titanium (c.p. Ti) and Ti6Al4V. This material (Ti/1.3HMDS) featured similar hardness, yield strength and better wear resistance than Ti6Al4V, as well as better electrochemical properties at physiological pH 7.4 than c.p. Ti grade 1 of our study. These excellent properties were obtained by utilizing an alternative mechanism to produce a microstructure of very fine titanium silicides and carbides (<100 nm) embedded in an ultra-fine-grained Ti matrix (365 nm). The grain refinement was achieved by high-energy ball milling of Ti powder with 1.3 wt.% of hexamethyldisilane (HMDS). The powder was consolidated by spark plasma sintering at moderate temperatures of 700 °C. The microstructure was investigated by optical and scanning electron microscopy (SEM) and correlated to the mechanical properties. Fluorescence microscopy revealed good adhesion of human mesenchymal stem cells on Ti/1.3HMDS comparable to that on c.p. Ti or Ti6Al4V. Biochemical analysis of lactate dehydrogenase and specific alkaline phosphatase activities of osteogenically induced hMSC exhibited equal proliferation and differentiation rates in all three cases. Thus the new material Ti/1.3HMDS represents a promising alternative to the comparatively weak c.p. Ti and toxic elements containing Ti6Al4V.     

Hematoporphyrin-derived soluble porphyrin-platinum conjugates with combined cytotoxic and phototoxic antitumor activity

To combine the cytotoxic activity of cisplatin and the phototoxicicity of hematoporphyrin derivatives in the same molecule, hematoporphyrin was derivatized at the two secondary alcohol positions by etherification with oligo- and poly(ethylene glycol) units. The two carboxylic acid groups of the propionate side chains were used to bind platinum fragments. The antiproliferative activity of 35 platinum complexes (0.5, 1, and 5 microM) differing in solubility and type of the platinum fragment and the corresponding porphyrin ligands were studied in tests with TCC-SUP and J82 transitional bladder cancer cells in the dark and after irradiation (lambda = 600-730 nm, 24 J/cm(2)). The most active compounds were found among the porphyrin-platinum conjugates bearing the diammine and (RR/SS)-trans-1,2-diaminocyclohexane ligand. These porphyrin-platinum conjugates, especially the water-soluble species, such as diammine(7,12-bis[1-(poly(ethylene glycol)-750-monomethyl ether-1-yl)ethyl]-3,8,13,17-tetramethylporphyrin-2,18-dipropionato)platinum(II), are promising candidates for the development of a novel type of photosensitizers with intrinsic cytotoxicity, which due to the porphyrin constituent may selectively enrich in tumor tissues.