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本文报告39例临床上除外右房肥大的P波高电压,此种P波高电压主要见于冠心病及急性颅脑疾患,二者之和占76.9%。其形态64%与肺性P波相同。产生的机制可能与结间束传导阻滞、中枢调节机能受累、交感神经兴奋性增高等有关。 相似文献
3.
Cesare M.N. Terracciano David Tweedie Kenneth T. MacLeod 《Pflügers Archiv : European journal of physiology》1997,433(4):540-542
. We have estimated sarcoplasmic reticulum calcium content using rapid application of caffeine on voltage clamped, isolated
guinea-pig ventricular myocytes. Caffeine induces the release of calcium from the sarcoplasmic reticulum and this calcium
is extruded from the cells by the sarcolemmal Na/Ca exchange. Integrating the inward Na/Ca exchange current thus allows estimations
of sarcoplasmic reticulum calcium content. Ventricular myocytes were stimulated to reach new steady-states by action potential
voltage clamps of varying duration. Once contractile steady-state had been reached caffeine was rapidly applied in place of
the next action potential and sarcoplasmic reticulum calcium content measured. Prolonging the action potential duration increased
sarcoplasmic reticulum calcium content and vice-versa. This calcium loading may underlie the positive inotropic effect of
increased action potential duration.
Received: 11 July 1996 / Received after revision: 15 October 1996 / Accepted: 26 November 1996 相似文献
4.
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
7.
微波照射对小鼠海马细胞膜ATPase活性和离子通道的影响 总被引:7,自引:1,他引:6
目的从电生理、酶学角度探讨微波照射对海马细胞的影响机理。方法用 2 4 5 0MHz连续波照射理疗机为照射源 ,以小白鼠为对象 ,观察微波照射强度为 1 0mW /cm2 时小鼠海马细胞膜Na+,K+ AT Pase、Ca2 +,Mg2 + ATPase活性、电压门控型Na+、K+、Ca2 +通道的变化情况 ,分别用组织化学染色法和膜片钳方法测定ATPase活性和离子通道功能。结果 1 )照射组海马Na+,K+ ATPase活性与对照组无显著差别 ,Ca2 +,Mg2 + ATPase活性比对照组显著降低 (P <0 .0 5 ) ;2 )照射组静息电位未发生显著变化 ,电压门控型Na+、K+、Ca2 +电流的诱导发生率显著地低于对照组 ,Na+电流峰值所在膜电位向去极化方向偏移 ,Na+电流衰减速率减慢 ,A电流的发生率显著低于对照。结论 2 4 5 0MHz微波照射小鼠 ,在 1 0mW /cm2 时 ,细胞的生存不会受影响 ,但海马细胞膜Ca2 +,Mg2 + ATPase活性受到抑制 ,电压门控型Na+、K+、Ca2 +离子通道受到损害 ,有可能影响学习记忆功能 相似文献
8.
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
9.
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
10.