Sympathetic blockade of isolated rat hindlimbs by intra-arterial guanethidine: the effect on blood flow and arterial-venous shunting

In order to improve the understanding of the role of sympathetic nerve degeneration in reimplantation failure, the hindlimbs of eight rats (Group I) underwent near-complete amputation. The soft tissues of the hindlimb were transected at the proximal thigh with the femoral artery, vein and femur left intact. The femoral vessels were clamped and guanethidine was infused into a branch of the femoral artery of the right leg of each animal, while saline was injected into the left leg. The clamps were removed after 15 minutes. A baseline preoperative injection of radiolabeled microspheres was made, and subsequent injections at 6, 12, 18, and 24 hours postoperation. Twelve rats (Group II) were then used to assess the amount of arterial-venous shunting preoperatively (n = 6) and at 18 hours postoperation (n = 6), by venous sampling. Blood flow to both limbs increased postoperation, but there was significantly more flow in the guanethidine treated limb at 18 and 24 hours postoperation. The amount of shunting was approximately 50% in both limbs at 18 hours, as compared to 10% preoperation. These results highlight the potential benefit of guanethidine and other sympathetic blocking agents in reimplantation to increase blood flow, decrease tissue ischemia and increase anastomotic patency rates. They also suggest that sympathetic nerve degeneration did not affect the volume of arterial-venous shunting in this model, but the difference in blood flow was likely due to arteriolar vasospasm. Further study is needed to elucidate the clinical significance of sympathetic nerve degeneration in reimplantation failure.     

A SUPERSONIC FLAME CUTTING TORCH

<正> 我们在不断改进过去的火焰切割喷嘴的基础上,经过理论计算,设计并试制成功火焰切割用超音速喷嘴,使用效果良好,现在已经推广使用。 一、纹影分析 为了鉴定并改进喷嘴的设计和制造,借助于纹影仪,可以对超音速氧射流密度梯度的变化进行观察和照相,并对氧射流流场进行定性分析。 根据理论计算,圆柱型喷嘴当其工作压力超过0.893公斤力/厘米~2(表压)时,出口     

空心阴极与多弧离子镀TiN涂层高速钢摩擦磨损特性的比较研究

本文用空心阴极和多弧离子镀方法在高速钢基体材料上制备了TiN涂层，研究评价了其摩擦磨损性能，并与刀具切削性能进行对比。结果表明：TiN涂层的摩擦磨损性能优于基体材料。从摩擦磨损机制上探讨了经TiN涂层的高速钢刀具比非涂层的刀具使用寿命明显延长，加工质量明显提高的原因。     

对英国、德国煤炭开采及安全管理的考察和认识

江西省煤炭行业管理办公室组织省有关煤炭管理、科研及煤矿企业专业技术人员,于2007年6月赴英国、德国进行了煤炭开采及安全管理考察,现将考察情况报告如下:     

Schizophrenia outpatients' perceptions of their parents: Is expressed emotion a factor?

The factors that mediate the association between expressed emotion (EE) and relapse in schizophrenia patients are still unknown. Many researchers hypothesize that interactions with high-EE individuals are stressful for patients, leaving them vulnerable to relapse. It would be useful to investigate whether patients perceive interactions with high-EE parents as stressful. In this study, associations were examined between levels of EE in parents and the types of personal memories patients had about these parents. EE ratings were obtained for both parents of 27 schizophrenia outpatients, and patients were asked to describe "happy, nonstressful" memories and "unhappy, stressful" memories during 2 interviews. Patients recounted fewer nonstressful memories and more stressful memories about high- versus low-EE parents. Implications of these results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceiving motion while moving: How pairwise nominal invariants make optical flow cohere.

Computer-generated sequences simulated observer movement toward 10 randomly placed poles, 1 moving and 9 stationary. When observers judged their direction of movement, or heading, they used 3 related invariants: The (a) convergence and (b) decelerating divergence of any 2 poles specified that heading was to the outside of the nearer pole, and the (c) crossover of 2 poles specified that heading was to the outside of the farther pole. With all poles stationary, the field of 45 pairwise movements yielded a coherent specification of heading. With 1 pole moving with respect to the others, however, the field a could yield an incoherent heading solution. Such incoherence was readily detectable; similar pole motion leading to coherent flow, however, was less readily detectable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

HIV seroprevalence amongst pregnant women in northeastern Zaire

Heparin co-factor II is in addition to antithrombin III another heparin dependent thrombin inhibitor. This glycoprotein blocks thrombin action not only in haemostasis but also in its other effects. Congenital deficiency of heparin co-factor II was found equally frequently among asymptomatic subjects and patients with thrombotic complications. Although its deficiency probably is not a serious risk factor of thromboembolic disease, it can promote its development in a significant way. The authors describe the case of a child with thrombotic complications and a congenital deficiency of heparin co-factor II.     

The N-terminal domain of human GABA receptor rho1 subunits contains signals for homooligomeric and heterooligomeric interaction

gamma-Aminobutyric acid type C (GABAC) receptors identified in retina appear to be composed of GABA rho subunits. The purpose of this study was to localize signals for homooligomeric assembly of rho1 subunits and to investigate whether the same region contained signals for heterooligomeric interaction with rho2 subunits. In vitro translated human rho1 was shown to be membrane-associated, and proteinase K susceptibility studies indicated that the N terminus was oriented in the lumen of ER-derived microsomal vesicles. This orientation suggested the involvement of the N terminus of rho1 in the initial steps of subunit assembly. To test this hypothesis, mutants were created containing only N-terminal sequences (N-rho1) or C-terminal sequences (C-rho1) of rho1. Co-immunoprecipitation studies revealed that N-rho1, but not C-rho1, interacted with rho1 in vitro. When coexpressed in Xenopus oocytes, N-rho1 interfered with rho1 receptor formation. Together, these data suggested that signals for rho1 homooligomeric assembly reside in the N-terminal half of the subunit. Sequential immunoprecipitations were then performed upon cotranslated rho1 and rho2 subunits which demonstrated that rho1 and rho2 interacted in vitro. Co-immunoprecipitation indicated that N-rho1 specifically associated with rho2. Therefore, the N-terminal regions of rho subunits contain the initial signals for both homooligomeric and heterooligomeric assembly into receptors with GABAC properties.