Foundations'' impact on policy making: results from a pilot study

Thirty-two consecutive patients with haematological disorders, in need of a permanent central venous catheter (CVC) were randomly allocated to have their CVC bandages (Tegaderm) changed once (OAW, n = 20) or twice (TAW, n = 19) a week. The two randomization arms were balanced in respect of age, sex, and underlying disease. The exit site of the CVC was inspected daily through the transparent bandage and erythema was noted. If severe erythema occurred, daily wet gauze dressings were applied. Samples for bacterial cultures were taken from the exit site of the CVC at every change of bandages. There was no difference in complications leading to removal of the CVC between the two groups (7/20 OAW vs. 7/19 TAW) or in CVC survival-time (P = 0.4). However, the OAW group had more positive CVC tip cultures (OAW 11/14 vs. TAW 2/9; P < 0.05) and a tendency to: (i) more extra dressings (P = 0.08); (ii) more cultures from the exit skin site showing high numbers of colony forming units (P = 0.07); (iii) shorter time to first exit site infection (P = 0.09); and (iv) more Gram-positive septicaemias (P = 0.08). Both clinical and bacteriological data in this study indicate that changing transparent polyurethane CVC bandages twice a week is superior to once a week.     

GaN材料系列的研究进展

ＧａＮ及其合金作为第三代半导体材料具有一系列优异的物理和化学性质，在光电子器件，高温大功率电子器件及高频微波器件应用方面具有广阔的前景，已成为当前高科技领域的研究重点，论述了这种材料的研究历史与发展现状，物理与化学性质，薄膜的生长方法及在光学电子和微电子器件应用于方面的研究进展。     

Occlusion of large atrial septal defects with a centering buttoned device: early clinical experience

A feasibility clinical study was conducted for the transcatheter occlusion of large ostium secundum atrial septal defects with the centering buttoned device. The centering buttoned device is a modification of the regular buttoned device in which a centering counter-occluder is sutured at the central 40% portion of the occluder. During centering it is stretched, forming a parachute-shaped structure and pulling the occluder over the center of the defect. During buttoning, the counter-occluder forms a double figure eight, opposing the right atrial side of the atrial septum. Occlusion was performed in 12 patients aged 6 to 56 years. All had been rejected for transcatheter occlusion by the regular buttoned device, because of either their defect size or the lack of adequate septal rim. The defect size varied between 23 and 31 mm, and the device size varied between 45 and 60 mm. Nine had immediate effective occlusions of their defects and three residual shunts. One patient with unbuttoning had hemolysis at 2 weeks and underwent surgery. Early results of the transcatheter occlusion of large atrial septal defects are promising, and larger clinical trials are justified.     

Selective monitoring of peptidase activities with synthetic polypeptide substrates and polyion-sensitive membrane electrode detection

A novel method to monitor specific peptidase activities in biological samples as complex as undiluted plasma/blood is described. The approach is based on the design of synthetic polypeptide substrates in which di- or triarginine sequences are linked to each other via one or more other amino acids recognized specifically by the peptidase to be determined. Detection of chymotrypsin and renin activities using synthetic substrates P4 (F-R-R-R-F-V-R-R-F-NH2) and P5 (R-R-R-L-L-R-R-L-L-R-R-R), respectively, serves to demonstrate the principles of this new assay system. A polyion-sensitive membrane electrode, prepared by doping polymer films with dinonylnaphthalene-sulfonate (DNNS), is shown to exhibit significant nonequilibrium electromotive force (EMF) responses toward these and other polycationic substrates at microgram/milliliter levels under physiological conditions. The same electrode, however, exhibits much smaller total EMF response toward the shorter fragments of the synthetic peptides generated by peptidase activity; hence, the addition of peptidase to a solution containing the synthetic substrate yields a change in electrode EMF response, the rate of which is proportional to the activity of peptidase present. Other synthetic polycationic peptides as well as natural polycationic peptides (e.g., protamine) that lack specific cleavage sites for chymotrypsin and renin, yet are detected by the DNNS-based membrane electrode, do not elicit any significant change in EMF response in the presence of the peptidases, confirming the feasibility and utility of the proposed bioanalytical method.     

The peak latency of orbital presaccadic spike potential with horizontal eye movements

A case of Macrozamia riedlei seed poisoning is described in a young Dachshund. Vomiting and depression commenced within 6 h of ingestion; other signs that developed included severe hepatopathy, jaundice, abdominal pain that was unresponsive to analgesics, severe gastro-intestinal haemorrhage and thrombocytopenia as well as crystalluria and marrow dyserythropoiesis. The dog was euthanased 6 days after ingestion of the seeds.