Immediate saccade amplitude disconjugacy induced by unequal images

We tested the ability of normal subjects to make changes in the conjugacy of their saccades. Subjects dichoptically viewed a grid the size of which was 10% larger in one eye. The grids were centred onto a flat screen at 57 cm or 1 m from the subject. Horizontal saccades immediately became larger in the eye viewing the larger grid. For some subjects this disconjugacy persisted even under subsequent monocular viewing. Such persistent changes occurred mainly in the field where the required disconjugacy was divergent for centrifugal saccades, convergent for centripetal saccades. Vertical saccades also developed compensatory disconjugacy; its amplitude was smaller but less variable. To explain these results we propose a fast associative learning mechanism that pairs peripheral disparity with saccades and is capable of producing saccade disconjugacy even in the absence of disparity. For horizontal saccades a secondary conditioning of monocular depth cues by the disparity would also be involved.     

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.     

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.     

High abundances of neurotrophin 3 in atopic dermatitis mast cell

Background  

Neurotrophin 3 (NT-3) is a member of the neurotrophin family, a group of related proteins that are known to regulate neuro-immune interactions in allergic diseases. Their cellular sources and role in the recruitment of mast cell precursors in atopic dermatitis have not been characterized in detail so far.     

Experimental investigation on histocompatibility of bovine collagen in rat tongue.

Authors injected a 1.5-2 cc Gax-Collagen into the tongue of 13 rats in order to examine the reactivity of the tissues around the graft and its attitude and duration. The research had practical purposes as the material is mainly used in E.N.T. for reconstructing the vocal cords. The animals have been sacrificed from 1 day to 9 months and the tongue subjected to the ordinary histologic methods. Our conclusions are as follows: a) a moderate inflammatory reaction following the introduction of the foreign body, then it attenuates and disappears at the third month; b) the implant is well tolerated, does not cause structural alterations in the surrounding tissues, in particular in the musculature where it is placed; c) a neovascularization appears, it lessens over the time, keeping itself only at the edge of the graft; d) in the formed fissures, fibroblasts, traces of collagen and neocollagen are present. All these conditions allow for taking root and the persistence of the implant. It is remarkable that the spherical form of the Gax-Collagen does not modify even if it has been implanted into a muscular organ and therefore subjected to severe and continuous mechanical stress.