Distinct white-matter aberrations in 22q11.2 deletion syndrome and patients at ultra-high risk for psychosis.

BACKGROUND: Patients with a deletion at chromosome 22q11.2 (22q11DS) have 30% lifetime risk of developing a psychosis. People fulfilling clinical criteria for ultra-high risk (UHR) for psychosis have 30% risk of developing a psychosis within 2 years. Both high-risk groups show white-matter (WM) abnormalities in microstructure and volume compared to healthy controls (HC), which have been related to psychotic symptoms. Comparisons of WM pathology between these two groups may specify WM markers related to genetic and clinical risk factors. METHOD: Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) were assessed using diffusion tensor magnetic resonance imaging (MRI), and WM volume with structural MRI, in 23 UHR patients, 21 22q11DS patients, and 33 HC. RESULTS: Compared to UHR patients 22q11DS patients had (1) lower AD and RD in corpus callosum (CC), cortical fasciculi, and anterior thalamic radiation (ATR), (2) higher FA in CC and ATR, and (3) lower occipital and superior temporal gyrus WM volume. Compared to HC, 22q11DS patients had (1) lower AD and RD throughout cortical fasciculi and (2) higher FA in ATR, CC and inferior fronto-occipital fasciculus. Compared to HC, UHR patients had (1) higher mean MD, RD, and AD in CC, ATR and cortical fasciculi, (2) no differences in FA. CONCLUSIONS: UHR and 22q11DS patients share a susceptibility for developing psychosis yet were characterized by distinct patterns of WM alterations relative to HC. While UHR patients were typified by signs suggestive of aberrant myelination, 22q11DS subjects showed signs suggestive of lower axonal integrity.

[The relationship between the temperature increase caused by phacoemulsification and the damage to the corneal endothelium]. / Zusammenhang zwischen der Temperatursteigerung bei der Phakoemulsifikation und den auftretenden Zellschäden am Hornhautendothel.

PURPOSE: Endothelial cell damage can be found after a phacoemulsification. The reason for this cell damage is not yet known. The temperature rise inside the anterior chamber during the emulsification of the lens is considered as a potential damage mechanism. The aim of this study was to investigate the relationship between the temperature increase and the cell damage. MATERIALS AND METHODS: This study was performed with 86 enucleated porcine eyes, which were divided into six groups A-F. Group A served as control group. Phacoemulsification was simulated in the groups B-E with different surgically relevant system settings. The temperature change was measured simultaneously with temperature sensors inside the anterior chamber. Inside the eyes of group F, the instruments were positioned and irrigation and aspiration were activated, but no ultrasound was applied. For all 86 corneas, the endothelial cell damage was quantified with a standardised evaluation protocol using scanning electron microscopy (SEM). A potential correlation was checked between the observed cell damage and the measured temperature rise. RESULTS: The highest temperature increase in group E with an obstructed aspiration line and an output power setting of 50 % was 17.77 °C. The temperature increase in group D with an output power setting of 100 % and unblocked fluid flow was significantly lower (p = 0.006). The highest temperature increase in group D was 8.89 °C. In contrast, the cells in group D were rated with a significantly lower score value than the cells in group E (p < 0.001). No significant correlation between the temperature rise and the cell damage could be obtained in due consideration of all measured data. However, an increase of the output power setting was connected with a non-linear increase of the cell loss. CONCLUSION: The temperature rise was not the main reason for the endothelial cell damage in the performed experiments. Therefore, there seems to be no causal relationship between the temperature increase inside the anterior chamber during a common phacoemulsification and the endothelial cell damage. Due to the strong dependence between the output power setting and the cell damage, the lowest output power setting should be used during surgery which ensures the emulsification of the nucleus.

[Preparation of the amniotic membrane with the waterjet]. / Zur Aufbereitung von Amnionmembranen mit dem Waterjet.

BACKGROUND: Ex vivo culturing of limbal stem cells on human amniotic membranes can be accelerated if all amniotic epithelial cells have been removed beforehand. A common application of acellular amniotic membranes is their use in cultivating autologous oral mucosal epithelial cells for transplantation in cases of bilateral stem cell insufficiency. Amniotic epithelial cells can be eliminated with enzymatic-chemical or mechanical methods or with a combination of both. MATERIAL AND METHODS: The efficacy of a waterjet cutter to eliminate amniotic epithelial cells from the amniotic membrane was investigated. Deep frozen placentas from healthy mothers were defrosted and a well-defined surface of the amniotic membrane (d = 15 mm) was treated with the waterjet in a standardized way. The waterjet used two different nozzles (pin-point and narrow stream nozzles). The applied system pressures with the pin-point stream nozzle (aperture 120 µm) were 30, 40 and 50 bar and the narrow stream nozzle was operated with pressures of 70, 80 and 90 bar on the amniotic membrane. A total number of 42 tissue samples were examined with an optical microscope using native trypan blue staining. For each type of nozzle and each application pressure two amnion samples were examined with a scanning electron microscope to analyze the efficacy of the mechanical epithelial cell elimination from the amniotic membrane. After medical imaging and histopathological examination the efficacy was graded using the following scale: 0 = no amniotic epithelial cells, 1 = no cells, low amounts of cell debris, 2 = single amniotic epithelial cells, large amounts of cell debris, 3 = loose cell layer, 4 = continuous sheet of epithelial cells. RESULTS: To eliminate epithelial cells from the surface of the amniotic membrane with the waterjet pinpoint stream nozzle (aperture: 120 µm) an application pressure of 30-50 bar was needed. The use of the narrow stream nozzle required a pressure of 70-90 bar. CONCLUSIONS: The preparation of amniotic membranes with the waterjet represents a precise option to mechanically eliminate amniotic epithelial cells from the amniotic membrane. The use of a waterjet cutter as an exclusively mechanical method without enzymatic-chemical substances may be a benefit, as cytotoxic effects on culturing limbal stem cells caused by chemical substances are not present.

Use of an electric field in an electrostatic liquid film radiator.

Experimental and numerical work was performed to further the understanding of an electrostatic liquid film radiator (ELFR) that was originally proposed by Kim et al.(1) The ELFR design utilizes an electric field that exerts a normal force on the interface of a flowing film. The field lowers the pressure under the film in a space radiator and, thereby, prevents leakage through a puncture in the radiator wall. The flowing film is subject to the Taylor cone instability, whereby a cone of fluid forms underneath an electrode and sharpens until a jet of fluid is pulled toward the electrode and disintegrates into droplets. The critical potential for the instability is shown to be as much as an order of magnitude higher than that used in previous designs.(2) Furthermore, leak stoppage experiments indicate that the critical field is adequate to stop leaks in a working radiator.

[Interproximal tooth cleansing of abutment teeth and pontic design]. / Interdentalraumhygiene an Bruckenpfeilern und Gestaltung des Zwischengliedes.

This clinical study was an attempt to find out if a patient's home care plaque control at his or her abutment tooth is more effectively enhanced by a modified ridge lap or a hygienic pontic design. Oral hygiene was performed either with a tooth brush alone or in combination with an interdental brush. We found that the effectivity of interproximal toothcleaning was not influenced by the pontic design and that only interdental brushes permit a good plaque control at the proximal area of the abutment tooth. This implies that "self cleansing" is non-existent in these tooth areas.

[Postoperative compression and regeneration following ulnar nerve transposition]. / Postoperative Kompression und Regeneration nach Ulnarisverlagerung.

In 58 patients with sulcus ulnaris syndrome the ulnar nerve was transposed intermuscularly under the ulnar flexor muscles. All the patients were examined after the operation clinically and electrophysiologically for recognizing the grade of postoperative regeneration and the possibility of a new compression. 86% postoperatively showed a good functional result. Electrophysiologically there was often found no normal duration and amplitude of the muscle action potential. 2 Patients showed symptoms of a postoperative compression of the transposed ulnar nerve under the origin of the ulnar flexor muscles. In order to avoid this complication the divided muscles must not be reunited with the medial epicondyle. Bad results after intermuscular transposition of the ulnar nerve are explained neither by a new compression nor by an unsatisfying regeneration of the nerve. They are the consequence of wrong diagnosis, common nerve lesion or fibrosis of muscle. A comparison with the results of other authers demonstrates that an additional interfascicular neurolysis is not necessary. The deep transposition of the ulnar nerve is recommended as the method of choice.