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941.
942.
You Mie Lee John J Cope Gabriele E Ackermann Katsutoshi Goishi Ehrin J Armstrong Barry H Paw Joyce Bischoff 《Developmental dynamics》2006,235(1):29-37
Vascular endothelial growth factor-receptors (VEGF-Rs) are pivotal regulators of vascular development, but a specific role for these receptors in the formation of heart valves has not been identified. We took advantage of small molecule inhibitors of VEGF-R signaling and showed that blocking VEGF-R signaling with receptor selective tyrosine kinase inhibitors, PTK 787 and AAC 787, from 17-21 hr post-fertilization (hpf) in zebrafish embryos resulted in a functional and structural defect in cardiac valve development. Regurgitation of blood between the two chambers of the heart, as well as a loss of cell-restricted expression of the valve differentiation markers notch 1b and bone morphogenetic protein-4 (bmp-4), was readily apparent in treated embryos. In addition, microangiography revealed a loss of a definitive atrioventricular constriction in treated embryos. Taken together, these data demonstrate a novel function for VEGF-Rs in the endocardial endothelium of the developing cardiac valve. 相似文献
943.
Y. Cheng R. Wong Y. O. Y. Soo W. S. Wong C. K. Lee M. H. L. Ng P. Chan K. C. Wong C. B. Leung G. Cheng 《European journal of clinical microbiology & infectious diseases》2005,24(1):44-46
In order to evaluate the efficacy of convalescent plasma therapy in the treatment of patients with severe acute respiratory syndrome (SARS), 80 SARS patients were given convalescent plasma at Prince of Wales Hospital, Hong Kong, between 20 March and 26 May 2003. Good outcome was defined as discharge by day 22 following the onset of SARS symptoms. Poor outcome was defined as death or hospitalization beyond 22 days. A higher day-22 discharge rate was observed among patients who were given convalescent plasma before day 14 of illness (58.3% vs 15.6%; P<0.001) and among those who were PCR positive and seronegative for coronavirus at the time of plasma infusion (66.7% vs 20%; P=0.001). 相似文献
944.
Isolated cardiac tissue from the ferret was repeatedly exposed to anoxia while perfused with glucose-containing Tyrode solution. In one series of experiments, papillary muscles were injected with aequorin to measure intracellular Ca2+. On the first exposure to anoxia, the Ca2+ transients often increased, but on subsequent exposures this increase disappeared and eventually the Ca2+ transients declined on exposure to anoxia. This decline in the Ca2+ transients could be converted back to an increase by a 1 h exposure to an elevated (×5) glucose concentration. Exposure of aerobic muscles to 10 mM lactic acid caused a similar increase in the Ca2+ transients to that seen in early exposures to anoxia. In a second series of experiments, performed on Langendorff-perfused hearts, measurements were made of glycogen concentration preceding, and lactate production during, exposures to anoxia. At a constant level of glucose, glycogen concentration and lactate production were found to decline on repeated exposures to anoxia, and both were increased after a period of elevated glucose and reduced stimulation frequency. These results suggest that the response of the Ca2+ transients to anoxia is dependent on the metabolic status of the muscle. The increase in the Ca2+ transients during an early eposure to anoxia may be a consequence of lactic acid production due to accelerated glycolysis. Repeated exposures to anoxia reduce glycogen concentration and lactate production and this reduces the rise in the Ca2+ transients. 相似文献
945.
Jo BJ Chung TS Lee MS Joo JY Ebert W Weinmann HJ Chien D Laub G 《Yonsei medical journal》1999,40(5):413-419
The purpose of this study was to compare the image quality of 3D-TOF MR angiography (MRA) using Gadomer-17 with that using Gd-DTPA in a flow phantom model, and to present preliminary data about the proper dose concentration of Gadomer-17. In the visual analysis of vessel conspicuity, we compared the quality of pre- and post-contrast MIP images. For quantitative analysis, the signal intensities were measured in the axial base 3D-TOF images, and then the relative contrast enhancement was calculated. The results of our studies were that: 1. Maximal signal intensities were obtained at 1 mmol/L of Gadomer-17 and 4 mmol/L of Gd-DTPA. 2. Flow-related signal loss was decreased by Gd-DTPA proportional to the concentration, but Gadomer-17 did not show such a dose accumulative effect. In conclusion, after comparing the results of Gd-DTPA, it was clear that improved MRA images and higher signal intensities of vessels were obtained when lower concentrations of Gadomer-17 were used. 相似文献
946.
Heng-Shuen Chen Fei-Ran Guo Chien-Tsai Liu Yue-Joe Lee Jye-Horng Chen Chia-Chin Lin Sheng-Mou Hou Bor-Shen Hsieh 《International journal of medical informatics》1998,50(1-3):59-68
National Taiwan University College of Medicine (NTUCM) introduced small groups of teaching and basic-clinical integrated courses for medical students in 1992. By using computer network and multimedia techniques, this study tried to overcome barriers to learning in small group teaching. The Department of Medical Informatics of NTUCM established campus networking and computer classrooms and provided Internet and intranet network services including mail, netnews, bulletin board systems (BBS), world wide web (WWW), gopher, ftp and local file servers. To implement an interactive learning environment, the authors first tried mail lists, newsgroups and BBS. Next an integrated learning system prototype on the WWW was developed to provide functions including online syllabus, discussion boards simulated to BBS, online talk, interactive case studies, virtual classroom with video on demand (VOD) and Internet medical resources. The results showed that after the medical students completed the required course of medical informatics and had good network access using a network to communicate with each other became a daily practice. In the future, the system will extend to the tutoring of clinical practice and continuing medical education. The authors expect a national medical education network and more international cooperation and exchange. 相似文献
947.
Myelin Degeneration in Multiple System Atrophy Detected by Unique Antibodies 总被引:2,自引:4,他引:2
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Akinori Matsuo Ichiro Akiguchi Gregory C. Lee Edith G. McGeer Patrick L. McGeer Jun Kimura 《The American journal of pathology》1998,153(3):735-744
A rabbit antiserum (anti-EP), induced against a synthetic peptide corresponding to residues 68 to 86 of guinea pig myelin basic protein, powerfully immunostained abnormal-appearing oligodendrocytic processes and cell bodies in demyelinating areas associated with multiple system atrophy (MSA). However, as we reported previously, the antiserum, which is highly specific for the sequence QDENPVV corresponding to human myelin basic protein residues 82 to 88, failed to recognize any structures in normal human brain. QD-9, a mouse monoclonal antibody raised against human myelin basic protein residues 69 to 88, which also recognizes specifically the epitope QDENPVV, gave the same results as did anti-EP. The unusual epitope recognized by anti-EP/QD-9 antibodies appears to be accessible in areas of myelin degeneration, and the antibodies have been shown to detect such areas in multiple sclerosis and infarcted brains. These antibodies detect myelin degeneration more widely than previous conventional methods. The present study emphasizes the importance of myelin degeneration in the pathogenesis of multiple system atrophy. 相似文献
948.
William C. Stanley Ji Di Chen William R. Lee George A. Brooks 《European journal of applied physiology》1987,56(3):299-305
Summary Mechanisms involved in the control of pulmonary ventilation were studied in seven male subjects following 6 min of exercise on a cycle ergometer at 98w. Circulation to the legs was occluded by thigh cuffs (27 kPa) during the last 15 s of exercise and the subsequent 4 min of recovery. Respiratory gas exchange and the tidal partial pressures of O2 and CO2 were measured breathby-breath. The results were compared to control studies without occlusion. There was a significant increase in both systolic and diastolic blood pressures during occluded recovery. Following occlusion systolic pressure remained elevated while diastolic pressure returned to control values. Occlusion during recovery caused hyperventilation during the first 1.5 min after exercise as evidenced by significantly higher
, PETO2, and lower PETCO2. Following the release of the cuffs PETCO2,
, and heart rate all increased significantly above control values, while PETO2 decreased. PETCO2 rose abruptly 14.5±0.9 s after the release of the cuffs. Marked increases inV
E and heart rate were seen, and occurred 30.8±1.5 s and 12.8±1.3 s, respectively, after cuff release. The 16.3±1.4 s lag between the increase in PETCO2 and
after occlusion suggests that the ventilatory response to a sudden load of hypercapnic blood is not mediated by a pulmonary chemoreceptor. Other receptors, probably the peripheral chemoreceptors, appear to be responsible for hypercapnic hyperventilation. 相似文献
949.
Moore DJ Zhang L Troncoso J Lee MK Hattori N Mizuno Y Dawson TM Dawson VL 《Human molecular genetics》2005,14(1):71-84
The identification of rare monogenic forms of Parkinson's disease (PD) has provided tremendous insight into the molecular pathogenesis of this disorder. Heritable mutations in alpha-synuclein, parkin, DJ-1 and PINK1 cause familial forms of PD. In the more common sporadic form of PD, oxidative stress and derangements in mitochondrial complex-I function are considered to play a prominent role in disease pathogenesis. However, the relationship of DJ-1 with other PD-linked genes and oxidative stress has not been explored. Here, we show that pathogenic mutant forms of DJ-1 specifically but differentially associate with parkin, an E3 ubiquitin ligase. Chemical cross-linking shows that pathogenic DJ-1 mutants exhibit impairments in homo-dimer formation, suggesting that parkin may bind to monomeric DJ-1. Parkin fails to specifically ubiquitinate and enhance the degradation of L166P and M26I mutant DJ-1, but instead promotes their stability in cultured cells. The interaction of parkin with L166P DJ-1 may involve a larger protein complex that contains CHIP and Hsp70, perhaps accounting for the lack of parkin-mediated ubiquitination. Oxidative stress also promotes an interaction between DJ-1 and parkin, but this does not result in the ubiquitination or degradation of DJ-1. Parkin-mediated alterations in DJ-1 protein stability may be pathogenically relevant as DJ-1 levels are dramatically increased in the detergent-insoluble fraction from sporadic PD/DLB brains, but are reduced in the insoluble fraction from parkin-linked autosomal recessive juvenile-onset PD brains. These data potentially link DJ-1 and parkin in a common molecular pathway at multiple levels that may have important implications for understanding the pathogenesis of inherited and sporadic PD. 相似文献
950.
Silver sulfadiazine (Ag-SD) is a useful antibacterial agent for wound treatment. However, recent findings indicate that the compound delays the wound-healing process. That delay may be reversed by treatment with growth factors. The purpose of this study, was to evaluate the cyto-protective effect of epidermal growth factor (EGF) against Ag-SD treated keratinocytes and to investigate the reversibility of the impaired wound-healing process by the co-supplementation of EGF. Four types of drug-loaded collagen sponge dressings with different concentrations of Ag-SD, EGF and Ag-SD + EGF were prepared. An immortalized keratinocyte, HaCaT cells, were cultured in 35-mm Petri-dish using Dulbecco's Modified Eagle's Minimal Essential Medium (DMEM) with 10% FBS. Cultures were treated with the samples submerged, and viabilities of cultures were evaluated using MTT assay. The wound heal efficacy was evaluated in a partial thickness burn mouse model. Cells treated with EGF showed a cyto-protective effect on 1% Ag-SD treated cells with significant increase in viable cell numbers at concentrations ranging from 1 to 50 microg/ml. The cytotoxicity of Ag-SD impaired wound healing, while the addition of EGF could reverse the impairment. This evidence suggests that EGF is a useful agent in the retardation of wound healing caused by Ag-SD. Therefore, a drug delivery system containing both EGF and Ag-SD, such as that used in the study, may be clinically relevant. 相似文献