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Arik Hasson Michael Fainzilber Eliahu Zlotkin Micha Spira 《The European journal of neuroscience》1995,7(4):815-818
A novel peptide toxin, PnIVB, isolated from the venom of Conus pennaceus blocks voltage-gated sodium current in Aplysia neurons. Complete blockade is obtained at a PnIVB concentration of 80±2.2 nM and 50% blockade at 16±0.86 nM. The potency of PnIVB in blocking Aplysia sodium current is four orders of magnitude larger than that of tetrodotoxin. The toxin has no paralytic activity when injected into fish. The rapid blockade of sodium current by PnIVB is not associated with a change in the activation or inactivation kinetics of the current, or with the reversal potential. Sodium current blockade is reversible after a 30 min wash with 50 times the bath volume. The novel conotoxin PnlVB can be used as a powerful tool for mollusc neurobiological research and as a molecular probe to explore the structure-function relations of voltage-gated sodium channel subtypes. 相似文献
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选择性输卵管造影与再通术在诊治阻塞性不孕中的价值(附200例报告) 总被引:2,自引:1,他引:1
目的 :评价选择性输卵管插管造影 (SSG)及再通术 (FTR)在输卵管阻塞性不孕中的诊治价值。材料和方法 :先经宫颈对常规子宫、输卵管造影 (HSG)显示输卵管阻塞的 2 0 0例不孕妇女的 380条输卵管进行插管 ,采用选择性插管至输卵管开口处推注 76 %泛影葡胺造影 ,对证实阻塞者行导丝再通术 ,术后随访 2~ 4个月。结果 :插管成功率 99% ,无严重并发症 ,复通率 90 % ,妊娠率 2 1% (4 2 / 2 0 0 )。结论 :SSG和FTR是目前诊治输卵管阻塞性不孕的最好方法 相似文献
5.
Gerhard Dahl 《Clinical and experimental pharmacology & physiology》1996,23(12):1047-1052
1. In the formation and function of gap junction channels two types of gates ought to be discriminated: the docking gate and the channel gates proper. The docking gate is involved in the transformation of a closed hemichannel to a patent gap junction channel. By definition the trigger mechanism for this gate and maybe even the gate itself is contained within the extracellular loops of the gap junction proteins, the connexins. The channel gates proper determine the open and closed states of the complete gap junction channels. 2. Probing the docking gate by mutagenesis of connexins and by synthetic peptides indicates that this gate is the consequence of complex interactions between a large fraction of the amino acids comprising the extracellular loops. Probably both inter- and intra-molecular interactions are involved, and disulfide exchange may be entailed in the stabilization of the open and closed states. 3. Of the various effectors on the channel gate(s) the voltage effects have obtained the most scrutiny to date. The response of gap junction channels and hemichannels is diverse, the various channels respond differently to transjunctional and membrane potential. No equivalent to the S4 segment representing the voltage sensor in other voltage dependent ion channels is present in the connexin sequences, instead mutations in various segments of connexins have been reported to affect the voltage dependence of gap junction channels. To understand the complexity of voltage effects on gap junction channels, non-connexin peptides may need to be considered as voltage sensors or as modifiers thereof. 相似文献
6.
Hitoshi Taguchi Koh Yamada Hideo Matsumoto Akira Kato Toshihiro Imanishi Koh Shingu 《Journal of anesthesia》1997,11(3):173-178
Purpose Several case reports indicate critical respiratory complications in relation to the double-lumen endobronchial tube (DLT).
A prospective survey for the airway problems in using the DLT is presented.
Methods One hundred adult patients undergoing thoracotomy for lung cancer were investigated. Tube malposition and airway obstruction
were searched using a fiber-optic scope. The endobronchial cuff was positioned just below the trachcal carina while the trachea
was intubated with a DLT (Rüsch). The distances of displacement, from the tracheal carina to the bronchial cuff, were measured
during anesthesia using an epidural catheter, which had marks every 5 mm. The distances for correcting the tube position were
measured at both the bronchial cuff and the level of the teethPaO2,PaCO2 andSPO2 were also measured.
Results Malposition (displacement over 5 mm from the correct position) was found in 42 patients, and 40 of them were in a withdrawal
direction, occurring at the postural change and during one-lung ventilation, especially during manipulation of the lung hilum.
Correcting distances at the level of the teeth were 15.3–3-times longer than those at the bronchial cuff. Airway deformities
and gradual withdrawal of the bronchial cuff were found in association with surgical manipulation. Obstruction occurred at
the tips of the tracheal tube in four patients and the bronchial tube in six patients, and at the tip of both in two patients.
Hypoxemia (PaO2<60 mmHg) occurred in four patients and hypercapnea (PaCO2>60 mm Hg) in two patients.
Conclusion Most of the DLT obstructions were associated with withdrawal malposition. Great attention to DLT displacement and airway deformity
is advised. 相似文献
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A Critical Period of Ventricular Fibrillation More Susceptible to Defibrillation: Real-Time Waveform Analysis Using a Single ECG Lead 总被引:1,自引:0,他引:1
PENG-WIE E. HSIA SYLVIA FRERK CYNTHIA A. ALLEN ROBERT M. WISE NERI M. COHEN RALPH J. DAMIANO Jr . 《Pacing and clinical electrophysiology : PACE》1996,19(4):418-430
Previous studies have suggested that variations in the underlying ventricular fibrillation (VF) waveform may be one of the factors responsible for the probabilistic nature of defibrillation. The heart appeared to be more susceptible to defibrillation at higher absolute VF voltages (AVFV). This study investigated in an open-chest canine model (n = 8), a newly developed system that analyzed the VF waveform in real-time, instantaneously determined the time to shock, and immediately delivered a fixed low energy DC shock. A two parameter tracking technique using a running long-term and short-term AVFV average was devised to automatically identify a high voltage peak area of the VF waveform, which has been hypothesized to represent a critical period susceptible to defibrillation. Using a DC shock estimated at the 50% success level, the performance using this technique in 58 defibrillation trials was compared to the performance of the conventional method of shocking at a fixed time (random shock method) in 62 trials. Patch size, electrode location, and discharge voltage were kept constant while VF duration, transmyocardial resistance (TMR), energy delivered, and AVFV at the point of shock were measured. Shock energy and current, TMR, and VF duration were similar with both shock methods. A significantly higher AVFV was observed for trials performed with the peak shock method (0.66 ± 0.02 mV) as compared to trials performed with the random shock method (0.25 ± 0.09 mV) (P < 0.003). Using lead II as the only sensing lead, the success rate was increased in 6 of 8 dogs (75%) with the new method. One animal showed identical performance, and one animal a worse performance. The overall increase in success rate was 24% using a single ECG lead (range 0%-100%; P < 0.04). Our data document that using this algorithm a period of high VF voltage can be detected in realtime. The improved success in the majority of animals supports the hypothesis that a critical period susceptible to defibrillation exists during VF. However, the high AVFV detected using a single ECG lead did not translate to an improved success rate in all animals. This suggests that other factors in addition to the VF voltage measured on a single lead of the ECG are important in characterizing this critical period. 相似文献
9.
简要介绍西门子SOMATOM CT高压发生器的工作原理,并着重分析了高压63A熔断丝炸裂故障原因及其判断与排除方法。文章指出了在检修高压发生器的过程中特别要注意的事项。 相似文献
10.
目的:探讨用氨甲喋呤(Methotraxate,MTX)配伍中药治疗条件适宜的输卵管妊娠的可行性及疗效。方法:对MTX配伍中治疗的输卵管妊娠86例临床资料进行分析。结果:82例治疗成功,成功率为95.35%,其中,治疗1个疗程69例,2个疗程13例,随访16例妊娠,1例2年后对侧输卵管妊娠,4例治疗失败者改手术治疗,病理见不同程度的滋养细胞溶解,绒毛坏死,出血,结论:使用MTX配伍中药治疗输卵管异位妊娠,方法简便易行,安全有效,副作用少,特别适合于基层医院。 相似文献