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61.
A nonlinear forecast system for the sea surface temperature (SST) anomalies over the whole tropical Pacific has been developed using a multi-layer perceptron neural network approach, where sea level pressure and SST anomalies were used as predictors to predict the five leading SST principal components at lead times from 3 to 15 months. Relative to the linear regression (LR) models, the nonlinear (NL) models showed higher correlation skills and lower root mean square errors over most areas of the domain, especially over the far western Pacific (west of 155 degrees E) and the eastern equatorial Pacific off Peru at lead times longer than 3 months, with correlation skills enhanced by 0.10-0.14. Seasonal and decadal changes in the prediction skills in the NL and LR models were also studied.  相似文献   
62.
The beta-adrenoceptor (beta-AR)-stimulatory guanine nucleotide-binding (Gs) protein system has been shown to play important roles in the cardiovascular system. The gene encoding the alpha-subunit of Gs proteins (GNAS1) is a candidate genetic determinant for hypertension. Because alcohol consumption is known to affect blood pressure partly through the beta-AR-Gs protein system, we examined the possible interaction between GNAS1 T393C polymorphism and drinking status in the association with hypertension in the present study. As a result, a non-significant but reasonable trend supporting the presence of an interaction was shown (p = 0.076). In line with this trend, the T393C polymorphism significantly interacted with drinking status in the association with systolic blood pressure (p = 0.028). Moreover, supporting the presence of an interaction, T allele carriers consistently had a higher probability of hypertension, higher systolic blood pressure, and higher diastolic blood pressure than CC homozygotes in non-drinkers and light drinkers. In contrast, CC homozygotes consistently had a higher probability of hypertension, higher systolic blood pressure, and higher diastolic blood pressure than T allele carriers in moderate to heavy drinkers. The present study also showed a significant interaction between the T393C polymorphism and drinking status in the association with pulse pressure (p = 0.026), reflected by a significant association between the T393C polymorphism and pulse pressure in moderate to heavy drinkers (p = 0.026). These findings may be helpful in conducting further molecular and biological studies on the relationship among the effects of alcohol, the beta-AR-Gs protein system, and hypertension.  相似文献   
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Bone marrow stromal cells (MSCs) increase vascular endothelial growth factor (VEGF) expression and promote angiogenesis after stroke. Angiopoietin-1 (Ang1) and its receptor Tie2 mediate vascular integrity and angiogenesis as does VEGF and its receptors. In this study, we tested whether MSC treatment of stroke increases Ang1/Tie2 expression, and whether Ang1/Tie2 with VEGF/ vascular endothelial growth factor receptor 2 (VEGFR2) (Flk1), in combination, induced by MSCs enhances angiogenesis and vascular integrity. Male Wistar rats were subjected to middle cerebral artery occlusion (MCAo) and treated with or without MSCs. Marrow stromal cell treatment significantly decreased blood-brain barrier (BBB) leakage and increased Ang1, Tie2, and occludin (a tight junction protein) expression in the ischemic border compared with MCAo control. To further test the mechanisms of MSC-induced angiogenesis and vascular stabilization, cocultures of MSCs with mouse brain endothelial cells (MBECs) or astrocytes were performed. Supernatant derived from MSCs cocultured with MBECs significantly increased MBEC expression of Ang1/Tie2 and Flk1 compared with MBEC alone. Marrow stromal cells cocultured with astrocytes also significantly increased astrocyte VEGF and Ang1/Tie2 expression compared with astrocyte culture alone. Conditioned media from MSCs alone, and media from cocultures of MSCs with astrocytes or MBECs, all significantly increased capillary tube-like formation of MBEC compared with control Dulbecco's modified Eagle's medium media. Inhibition of Flk1 and/or Ang1 significantly decreased MSC-induced MBEC tube formation. Knockdown of Tie2 expression in MBECs significantly inhibited MSC-induced tube formation. Our data indicate MSC treatment of stroke promotes angiogenesis and vascular stabilization, which is at least partially mediated by VEGF/Flk1 and Ang1/Tie2.  相似文献   
66.
改良W形回肠代膀胱术的疗效观察(附36例报告)   总被引:5,自引:0,他引:5  
目的 :探讨改良W形回肠代膀胱术的疗效。方法 :对 36例膀胱肿瘤患者行根治性膀胱切除、W形回肠代膀胱术 ,并对术式进行改进。结果 :36例手术时间平均 4 .2h。术后 31例随访 4~ 19个月 ,平均 10 .6个月 ,无严重并发症 ,均无瘤生存。患者一般于术后 3周自主可控性排尿 ,日间尿控率为 10 0 % ,术后 3、6、12个月夜间尿失禁发生率分别为 2 2 .5 %、11.1%及 6 .2 %。术后 6个月尿动力学检查膀胱容量 (36 0± 30 )ml,最大尿流率 (13.6± 2 .6 )ml/s,剩余尿量 (11.5± 5 .8)ml,充盈期膀胱压力明显低于尿道闭合压。新膀胱造影发现新膀胱呈球形 ,完全位于盆腔 ,未见输尿管反流。B超及IVU检查发现原上尿路积水 4例均明显减轻 ,其余未发现输尿管狭窄和上尿路积水征象。无高氯性酸中毒 ,肾功能正常。结论 :改良W形回肠代膀胱术手术时间短 ,操作简单 ,创伤轻 ,并发症少 ;新膀胱容量大 ,内压低 ,顺应性好 ,功能接近于正常膀胱 ,保持原位排尿 ,明显提高了患者术后生活质量 ,值得临床推广应用。  相似文献   
67.
 To monitor the lead hazards in industries and to investigate the prevalence of elevated blood lead levels (BLLs) in lead-exposed workers, a lead surveillance system (PRESS-BLLs) has been established and operated in Taiwan, Republic of China, since July 1993. A cohort of lead-exposed workers who received a periodic annual health examination at 55 accredited hospital laboratories was constructed. A total of 9807 separate BLL measurements were reported to the system in 1994. The mean BLL was 15.8 μg/dl in male workers and 11.6 μg/dl in female workers. The mean BLL of lead-exposed workers was significantly (P<0.05, z-test) higher than that of the general Taiwanese population (8.6 μg/dl for males and 6.7 μg/dl for females). In addition, the BLLs of 983 (10.0%) workers exceeded the regulatory action level (40 μg/dl for males; 30 μg/dl for females). The workplaces and homes of 57% of the workers with elevated BLLs were thoroughly investigated to determine the sources of lead contamination. These actions identified the causes of elevated BLLs and set up strategies to reduce workers’ lead exposure. The establishment of this occupational lead surveillance system represents a method for monitoring of lead hazards from occupational and environmental settings to prevent lead poisoning. The information acquired from the system can help in the setting up of a priority of prevention and the development of control measures. It is also useful for further monitoring of changes in the BLLs of the lead-exposed-worker cohort. The Health Department of Taiwan can use this information to evaluate the effectiveness of current industrial hygiene practice. Subjects with elevated BLLs have been medically treated and placed on long-term follow-up for sequelae. Received: 2 September 1996/Accepted: 29 November 1996  相似文献   
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50只大鼠用乌拉坦麻醉,箭毒制动。通过阻断腹主动脉血流以模拟腰段脊髓的局部缺血和再灌流损伤,玻璃微电极记录L2节段脊髓单位放电(SCUDs),观察缺血再灌流时脊髓神经元对腓神经刺激(PNV),内脏大神经刺激(VLNV)及两者同时刺激(SV)的反应。结果在缺血前所记录的133个自发放电单位中,对3种刺激均产生兴奋(E)、抑制(I)及无反应(NR)3种形式的反应,表明大鼠L2节段脊髓存在躯体、内脏和躯体内脏反应性神经元,并有会聚和阻塞现象。在脊髓缺血再灌流时,神经元对PNV、VLNV、SV也产生E、I、NR3种形式的反应,提示脊髓缺血再灌流时神经元对躯体和内脏传入刺激的反应形式不受影响;但缺血时SCUDs对PNV、VLNV产生反应的单位数减少,这表明脊髓缺血损伤时神经元对躯体和内脏传入刺激的反应性减弱,随着缺血损伤加重,脊髓神经元对躯体内脏信号的整合功能下降  相似文献   
70.
.OH生成液0.05ml.100g^-1经胶静脉注入心脏,可使麻醉大鼠的左心室收缩压力、左心室压力与心率乘积、左心室压力上升最大速率和左心室压力下降最大速率明显下降。  相似文献   
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