Platelet-activating factor mediates angiotensin II-induced proteinuria in isolated perfused rat kidney

Isolated kidney preparations (IPK) from male Sprague Dawley rats perfused at constant pressure were used to evaluate the effect of angiotensin II (AII) and platelet-activating factor (PAF) on renal function and urinary protein excretion. Compared with basal, intrarenal infusion of AII at 8 ng/min caused a progressive increase in protein excretion (11 +/- 6 versus 73 +/- 21 micrograms/min) in parallel with a decline in renal perfusate flow (RPF) (29 +/- 3 versus 18 +/- 3 ml/min). Addition to the perfusate of PAF at 50 nM final concentration also induced proteinuria (9 +/- 4 versus 55 +/- 14 micrograms/min) but did not change RPF (29 +/- 3 versus 30 +/- 3 ml/min). Preexposure of isolated kidneys to the PAF receptor antagonist WEB 2086 prevented the increase in urinary protein excretion induced by AII infusion (basal: 13 +/- 6; post-AII: 12 +/- 7 micrograms/min) but failed to prevent the vasoactive effect of AII (RPF, basal: 30 +/- 2; post-AII: 21 +/- 3 ml/min). In additional experiments, dexamethasone reduced the proteinuric effect of PAF remarkably. These results indicate that in isolated kidney preparation: (1) AII infusion induced proteinuria and decreased RPF; and (2) the effect of AII in enhancing urinary protein excretion was completely prevented by a specific PAF receptor antagonist, which, however, did not influence the AII-induced fall in RPF. It is suggested that PAF plays a major role in AII-induced changes in the permselective function of the glomerular capillary barrier.     

Pregnancy loss and autoantibodies against phospholipid-binding proteins

We investigated the utility of two approaches for exploiting pleiotropy to search for genes influencing related traits. To do this we first assessed the genetic correlations among a set of five closely related quantitative traits (Q1, Q2, Q3, Q4, Q5). We then used the genetic correlations among these five traits both to remove the common genetic effects of the four remaining traits, thereby identifying the unique genetic contribution to each trait, and to extract a synthetic phenotype which exploits the shared genetic information (pleiotropy) among these five traits. After obtaining these conditional traits, we then searched for evidence of quantitative trait loci (QTLs) (using variance component linkage) influencing the unique residual genetic component for each trait as well as those influencing the expression of the synthetic traits. From this work, we conclude that the removal of the common genetic effects of other traits in a group may be of greater utility when the majority of the pleiotropy initially detected between traits is attributable to the shared additive effects of polygenes, rather than to those of major loci. By contrast, decomposition of the genetic covariance matrix to its principal components is a greater utility when the majority of pleiotropy is attributable to major loci.     

消息推送在移动高级应用中的研究与实现

为了使移动终端用户能够及时查看到电力业务更新消息,提出消息推送技术在移动高级应用中的研究。首先介绍消息推送的实现方式及原理,然后就iOS与Android系统两大主流移动系统平台的消息推送机制进行研究,提出在两大主流移动系统平台上实现消息推送的解决方案,并在企业移动驾驶舱的高级应用中实现消息推送,使终端用户能够实时查看到更新的消息。     

Standardization of islet isolation outcome – A new automatic system to determine pancreatic islet viability

Pancreatic islet transplantation is emerging as a therapeutic approach for patients affected by diabetes. This approach consists of a minimally invasive procedure replacing insulin-producing cells (pancreatic islets). The technique has been proven successful, but limitations have been identified. One of the major challenges of the procedure is the counting of the isolated pancreatic islets, which is currently jeopardized by subjectivity and inaccuracy. Determination of the accurate islet number is a crucial factor in determining the correlation between the isolation product and clinical outcome. In the proposed study, we have developed software capable of objectively evaluating islet numbers and other viability variables by image analysis. This software is based on image processing and feature extraction algorithms for recognition of the area of interest. This is the first step toward standardization of the isolation outcome and potential clinical success predictability.     

Dental microwear of Griphopithecus alpani

The examination of microscopic dental wear allows inferences to be made about diet in extinct species. This study reconstructs the diet of Griphopithecus alpani, a 15 Ma fossil hominoid from the Miocene site of Pa?alar in north-western Turkey, using scanning electron microscopy (SEM) to examine the microscopic wear on its molar teeth. The microwear patterns of Griphopithecus are compared with those of three extant hominoid taxa-Gorilla gorilla gorilla, Pan troglodytes verus, and Pongo pygmaeus pygmaeus. The microwear on three occlusal wear surfaces is examined in this study, and sex and age differences are also included. Analysis of variance is performed on the following microwear variables-feature density, pit density, striation density, the ratio of pits relative to striations, pit widths, and striation widths. Griphopithecus has significantly higher microwear feature densities and higher percentages of pits than Gorilla. It also has larger pit frequencies and narrower striations than both Pan and Gorilla. There are no significant differences between the microwear patterns of Griphopithecus and Pongo. This suggests that the diet of Gripho-pithecus was more similar to that of Pongo, which consumes mainly fruit, and occasionally hard and unripe fruits and nuts, than to that of Pan and Gorilla. In addition, the high percentage of pits displayed by Griphopithecus may indicate that it was ingesting harder fruits and/or objects than the extant hominoids, although this is not a significant difference. There also are consistent variations in the microwear present on the three different wear facets examined in the study-Phase II facets display more microwear and pitting than the Phase I surface examined. The results of this study do not indicate variation in dental microwear according to sex or age.     

A comparison of thromboelastography with heparinase or protamine sulfate added in vitro during heparinized cardiopulmonary bypass

Thromboelastography (TEG) has been used after cardiopulmonary bypass (CPB) to diagnose excessive postoperative hemorrhage. Conventional TEG during CPB is not possible due to the sensitivity of the TEG to even small amounts of heparin, which produces a nondiagnostic tracing. The purpose of this study was to compare heparin neutralization using heparinase or protamine in TEG blood samples obtained during CPB. TEG testing was performed on 48 patients before, during and after CPB. Tissue plasminogen activator activity and antigen were measured on a subset of 32 patients. We found: 1) heparinase neutralized at least 10 IU/ml heparin while 1.6 ug/ml protamine neutralized up to 7 IU/ml heparin, 2) in samples with complete heparin neutralization by both methods, there was no significant difference in the R values, 3) while there was good correlation for other TEG parameters between heparinase and protamine treated samples, heparinase treatment produced shorter K values and higher angle, MA and A60, 4) while fibrinolysis was detected using both methods, heparinase treatment suppressed fibrinolysis in the TEG in both samples from patients and after in vitro addition of tissue plasminogen activator, 5) TEG was not a sensitive indicator of t-PA activity, detecting only 21% of samples with increased t-PA activity during bypass, and 5) heparinase was at least 100 times more expensive than protamine. We conclude that while both heparinase and protamine can be used to neutralize heparin in TEG samples obtained during CPB, protamine neutralization is more sensitive to fibrinolysis and less expensive, but the protamine dose must be carefully selected to match the heparin level used at individual institutions.     

Absolute emission quantum yield determination of self-assembled mesoporous titania films grafted with a luminescent zinc complex

A luminescent zinc complex was successfully incorporated to mesostructured porous titania films through a grafting process. The resulting films show an intense blue-emission increasing with functionalization time. The emission quantum yield of these newly synthesized films was quantitatively and accurately determined by measurements carried by an integrating sphere.     

Microwave-assisted oxygenation of melt-processed bulk YBa2Cu3O7-δ ceramics

The properties (superconducting and non-superconducting) of YBa₂Cu₃O_7-δ bulk ceramics (YBCO) are strongly dependent on the oxygen deficiency, δ. Unfortunately, whether sintering or melt-processing is used to form the material, the final oxygen content is usually far from that which gives the optimum superconducting properties (δ≲0.1). Because of this, an additional oxygenation stage has to be carried out in which the material is heated and held at some elevated temperature (∼400–500 °C) for a significant time (often > 100 h) to allow oxygen to diffuse into the sample. Other diffusion-based processes (e.g. sintering) are known to be substantially enhanced in the presence of a microwave field, and it is reasonable to expect that the diffusion of oxygen into YBCO may also benefit from the application of such technology. The oxygenation of melt-processed YBCO using conventional and microwave-assisted heating has been compared. The diffusion coefficient at 400 and at 450 °C is shown to be enhanced by about 30% through the application of a high-frequency microwave field. Because the oxygenation time is inversely proportional to the diffusion coefficient, this represents a significant reduction in process time. The equilibrium value of the oxygen content is not affected by the application of a microwave field, and therefore the sample temperature must be the same for both microwave-assisted and conventional processing. Consequently, the observed enhancement is an example of a genuine non-thermal microwave effect. This revised version was published online in November 2006 with corrections to the Cover Date.     

Water effects on the bond strength of concrete/concrete adhesive joints

The paper discusses the experimental work by the authors investigating bond strength of epoxy adhesives and their efficiency when joining to concrete elements; the epoxies studied were those currently used in the construction industry. Flexural tests were undertaken to determine the mechanical properties of the exposed and the control specimens of three different epoxy adhesives. In addition, the water resistance of concrete/concrete epoxy joints was investigated by comparing bond strength with those of control samples; the maximum period of immersion was one month. A reduction in the glass transition temperature and the stiffness at short immersion time was found for all the adhesives employed, with a subsequent slight increase for prolonged immersion, while the effects on the strengths resulted almost proportional to their initial values. The effect of water on the adhesion of the joints was found to be significant, especially at longer immersion times; the bond strength of concrete–adhesive specimens reduced by 30% after one month of immersion in water.     

Problem-based medical education: development of a theoretical foundation and a science-based professional attitude

Problem-based learning, combined with early patient contact, integration between different subject areas, elements of multiprofessional education, and special emphasis on the development of communications skills has become the basis for the medical curriculum at the Faculty of Health Sciences in Link?ping. Critics have questioned the depth of the scientific and theoretical aspects of the curriculum. Through a series of specific measures in the organization of the curriculum and examinations, and due to the pedagogical principles involved per se, our claim is that students graduating at Link?ping do possess the required theoretical knowledge and a scientific attitude to the practice of medicine, at least equivalent to that obtained in a more conventional medical curriculum. One such specific measure is that all students perform one field study and two scientific studies during the course of the curriculum. An investigation of student opinions regarding the value of performing scientific projects of their own have shown that these projects have had a positive impact on the students' general scientific attitude and their willingness to engage in future scientific work. The specific skills acquired, as confirmed by oral examinations, were largely determined by the scientific nature of the chosen field of study. Our graduates have not yet progressed far enough in their careers for comparisons to be made on the basis of the Swedish Licensing Board Internship Examinations, but continuing evaluations of students, graduates and licensed doctors emerging from the curriculum will provide future evidence as to whether our present evaluation is correct.