Systemische Freisetzung von Prostanoiden nach chirurgisch induzierter Verletzung des Lungengewebes

In a prospective study, the systemic inflammatory consequences of surgery-induced lung tissue injury were evaluated using biochemical markers. The aim was to examine whether this type of injury produces a specific pattern of prostanoid plasma levels (prostacyclin, thromboxane, PGE₂, PGF_2α, and PGM). We, therefore, compared 18 patients (group 1) who underwent thoracotomy without injury to the lung with 26 patients (group 2) that had a resection of pulmonary tissue due to benign diseases. Group 2 patients clearly revealed increased plasma levels of C-reactive protein as well as of the granulocyte-specific PMN-elastase. In particular, there was a pronounced release of prostacyclin and its antagonist thromboxane A₂ following lung tissue resection. In contrast to group 1 patients, lung tissue damage resulted in immediately elevated plasma levels of PGF_2α and PGE₂. When, however, taking into account the time course of PGM, the stable cleavage product of PGF_2α, there was no hint of an altered pulmonary metabolic capacity. Presumably, this pattern of elevated prostanoid levels in group 2 is the result of the surgical damage to the lung tissue. Therefore, it can be suggested to be specific for that type of injury. Thus, the release of prostanoids following surgery-induced lung tissue damage may indicate the importance of these mediators, particularly in thoracic injuries associated with lung damage since those may lead to post-traumatic pulmonary dysfunction. These substances may also be useful in evaluating both the severity and the extent of lung tissue damage following major trauma.     

Humerus reconstruction after gunshot fracture]

High-velocity bullits can cause severe blast injuries with shattering and defects of the large bones. Initial external fixation is followed by rebuilding of the bone, which is difficult due to concomitant infection, poor revascularization and lack of a suitable bone bed. A case report of an injured African soldier shows the follow-up and difficulties of reconstruction of the shattered humerus by repeated spongious bone grafting. After successful remodeling of the bone, external fixation is followed by ASIF dynamic compression-plate osteosynthesis.     

Learned alcohol aversions in rats: gustatory and olfactory components

The gustatory and olfactory basis of learned alcohol aversions was examined by testing rats with either gustatory neocortex ablations, olfactory bulb ablations, or a combination of both ablations. In the first experiment operated rats were compared with control rats in the acquisition of a learned alcohol aversion. In the second experiment, the effect of ablations on preoperatively-learned alcohol aversions was examined. Rats lacking gustatory neocortex learned and retained alcohol aversions normally although these rats extinguished the aversions faster than normal rats. Olfactory bulb ablation alone failed to disrupt normal aversion learning but completely eliminated retention of a previously acquired aversion. Combination ablations produced severe deficits both in acquisition and retention of learned alcohol aversions. The results indicate that, besides having gustatory qualities, the odor quality of alcohol is important in determining the associative and memorial characteristics of alcohol.     

Influence of stress simulation parameters on the fracture strength of all-ceramic fixed-partial dentures.

OBJECTIVES: This in vitro study tested the influence of diverse stress simulation parameters on the fracture strength of all-ceramic three-unit fixed partial dentures (FPDs). METHODS: All-ceramic FPDs made of Empress 2 (Ivoclar-Vivadent, FL) were exposed to thermal cycling and mechanical loading (TCML) with varying loading parameters such as chewing force (amount, frequency), thermal loading, lateral jaw motion, abutment material, artificial periodontium or antagonistic denture. To investigate the influence of the abutment material, human teeth, polymer abutments and alloy abutments were used. Two different TCML devices with pneumatic or weight loading were compared. FPDs without aging were used as a control. RESULTS AND SIGNIFICANCE: Combined thermal and mechanical loading significantly reduced the FPD fracture resistance from 1832N to 410N. Duplication of chewing frequency, phase load increase or additional lateral movement did not effect the results. Increasing chewing force, artificial periodontium, and antagonist or abutment material reduced the fracture resistance of the tested FPDs. Different devices with weight or pneumatic loading had no significant influence on the loading capacity of the FPDs. Artificial aging should be performed combining thermal cycling with mechanical loading. Simulation of the artificial periodontium, human antagonists and abutments should be included to achieve a significant aging.     

Distinct effects of surgical denervation on hepatic perfusion, bowel ischemia, and oxidative stress in brain dead and living donor porcine models.

The liver function and perfusion following brain death is mainly influenced by the sympathetic nerves and hormones. We examined the specific influence of surgical liver denervation on systemic and hepatic perfusion parameters, bowel ischemia and oxidative stress in hemodynamically stable BD and control (living donor [LD]) pigs. Brain death was induced in 8 pigs via saline infusion into the balloon of an epidural Tieman-catheter (1 mL/15 minutes) and compared to the control group (n = 6) over 4 hours. At 2 hours postoperatively, complete liver denervation was initiated. We analyzed systemic cardiocirculatory parameters (mean arterial pressure, aortic flow, bowel ischemia (endotoxin, and endotoxin-neutralizing capacity) and oxidative stress (total glutathione in erythrocytes [tGSH(E)]) and compared them to local/hepatic perfusion parameters (hepatic artery and portal venous flow, liver blood flow index, and microperfusion), local bowel ischemia (intramucosal pH [pHi] of stomach [pHi(S)]/colon[pHi(C)]), and liver oxidative stress (glutathione [rGSH(L), GSSG(L)]). Following brain death, the parameters including mean arterial pressure, aortic flow, pHi, endotoxin, and tGSH(E) showed no significant changes at 2 hours. Portal venous flow and microperfusion were decreased significantly and hepatic arterial buffer response was ineffective. Hepatic oxidative stress was increased in BD animals (decrease rGSH(L), increase GSSG(L)). Surgical denervation/manipulation increased portal venous flow significantly, hepatic arterial buffer response became effective, and stomach pHi decreased (BD and LD groups). Hepatic oxidative stress was reduced in the BD group (increase rGSH(L)/GSSG(L); P < 0.001) while it was increased in the LD group (decrease rGSH(L)/GSSG(L); P < 0.001). In conclusion, denervation reduces hepatic oxidative stress in BD only in contrast to the LD. The reciprocal effect of denervation depends on the state of neural activation and postulates a potential benefit of surgical denervation before organ harvesting in brain death.     

Komplikationen navigierter Eingriffe an der Wirbelsäule

Both 2D and 3D computer navigation systems have become important tools in the operative treatment of spinal injuries. 2D navigation utilizes a modality-based dataset from the C-arm, while 3D-navigation is based on a non-modality-based dataset from conventional computed tomography or on 3D modality-based ascertainment of data by an isocentric C-arm equipped with an appropriate computer. Experimental and clinical studies have shown increasing accuracy of transpedicular screw placement with all types of computer navigation than with traditional implantation, but unsatisfactory levels of precision are still recorded even when computer navigation is used. Before computer navigation systems can be used with sufficient precision it is necessary to know the potential sources of error for each of the various modalities. These extend from the data acquisition through data transfer and preparation of the dataset for use in computer navigation to intraoperative use of each navigation system. Those who are starting to use such systems must undergo a specialized course of instruction followed by supervised training, and any surgeon who applies them must be sufficiently experienced and well informed to be able to view them with a well-founded criticism; only then are identification and consequent avoidance of complications of computer navigation possible.