Effects of Pharmacological Autonomic Blockade on Dual Atrioventricular Nodal Pathways Physiology in Patients with Slow-Fast Atrioventricular Nodal Reentrant Tachycardia

The purpose of this study was to investigate the atrioventricular AV nodal physiology and the inducibility of AV nodal reentrant tachycardia (AVNRT) under pharmacological autonomic blockade (AB). Seventeen consecutive patients (6 men and 11 women, mean age 39 ± 17 years) with clinical recurrent slow-fast AVNRT received electrophysiological study before and after pharmacological AB with atropine (0.04 mg/kg) and propranolol (0.2 mg/kg). In baseline, all 17 patients could be induced with AVNRT, 5 were isoproterenol-dependent. After pharmacological AB, 12 (71 %) of 17 patients still demonstrated AV nodal duality. AVNRT became noninducible in 7 of 12 nonisoproterenol dependent patients and remained noninducible in all 5 isoproterenol dependent patients. The sinus cycle length (801 ± 105 ms vs 630 ± 80 ms, P < 0.005) and AV blocking cycle length (365 ± 64 ms vs 338 ± 61 ms, P < 0.005) became shorter after AB. The antegrade effective refractory period and functional refractory period of the fast pathway (369 ± 67 ms vs 305 ± 73 ms, P < 0.005; 408 ± 56 ms vs 350 ± 62 ms, P < 0.005) and the slow pathway (271 ± 30 ms vs 258 ± 27 ms, P < 0.01; 344 ± 60 ms vs 295 ± 50 ms, P < 0.005) likewise became significantly shortened. However, the ventriculoatrial blocking cycle length (349 ± 94 ms vs 326 ± 89 ms, NS) and effective refractory period of retrograde fast pathway (228 ± 38 ms vs 240 ± 80 ms, NS) remained unchanged after autonomic blockade. Pharmacological AB unveiling the intrinsic AV nodal physiology could result in the masking of AV nodal duality and the decreased inducibility of clinical AVNRT.     

微晶蜡非催化氧化反应的神经网络模型

对微晶蜡进行了非催化空气氧化，并利用人工神经网络将氧化微晶蜡的酸值、酯值及微晶蜡的氧化条件（反应温度、空气流量和反应时间）进行关联，建立了微晶蜡非催化氧化的酸值、酯值的神经网络模型，并用该模型预测了反应条件对微晶蜡氧化反应过程的影响。结果表明，该模型不但具有较高的计算精度，而且具有满意的预测能力。     

老年患者不同靶浓度罗库溴铵肌松效应的比较

目的比较老年患者不同靶浓度罗库溴铵的肌松效应。方法择期全麻老年患者100例,ASAⅡ级,随机分为4组(n=25),A组、B组和C组麻醉诱导气管插管时效应室靶浓度(Ce)为3μg/ ml,术中维持Ce分别为0.6、0.8、1.0μg/ml;D组麻醉诱导气管插管时Ce为3.3μg/ml,术中维持Ce为0_8μg/ml。记录肌松起效时间、恢复时间和恢复指数。评价气管插管条件和术中肌松程度。记录手术及TCI时间、罗库溴铵总用药量和期间用药量[总用药量,(体重×TCI时间)]。结果4组均可顺利完成气管插管,D组起效时间较A组、B组和C组缩短(P<0.05);A组肌松满意率低,B组、C组和D组均可维持满意肌松,但C组罗库溴铵用量较多,术中肌松程度较大,术后恢复时间较长(P<0.05)。结论麻醉诱导气管插管时罗库溴铵Ce为3.3μg/ml、术中麻醉维持Ce为0.8μg/ml,可产生满意的肌松条件,且有利于术后肌松恢复,是一种适用于老年患者合理的TCI给药方案。     

Patterns of angiogenesis in neural transplant models: I. Autonomic tissue transplants

Functional vascular connections must form rapidly to prevent ischemic damage to grafted neural tissues. The temporal sequence by which transplant circulation is re-established provides information about the angiogenic capacity of either intact or damaged CNS blood vessels. This study compares the time course and mechanism of vascular reperfusion in allografts of superior cervical ganglia or adrenal medulla inserted either into the fourth ventricle or directly into the parietal cortex of perinatal rats. Tritiated thymidine was administered to recipients to determine angiogenic patterns at various postoperative time periods. After processing for light microscopic autoradiography, host and graft endothelial labelling indices were determined in order to establish the temporal sequence and location of vascular proliferation. Correlative electron microscopy depicted the morphological changes in transplant vasculature. Some recipients were prelabelled with 3H thymidine prior to transplantation to determine if host vessels invaded the grafts. Intraventricular graft vessels initially collapsed but sustained minimal ischemic damage and were completely reperfused by 24 hours postoperative. Adjacent intact host vessels attained peak 3H thymidine incorporation at 20 hours. Intrinsic graft vessels were radioactively labelled only after 48 hours. Intraparenchymal transplants surrounded by minimal trauma exhibited a similar temporal sequence of reperfusion and host endothelial proliferation. Intrinsic graft vessels in intraparenchymal grafts sustained more severe damage. With increased trauma, a concomitant delay in graft reperfusion time was observed. Grafts within prelabelled hosts rarely contained any labelled endothelium, indicating that anastomotic connections were made between original, intrinsic graft vessels and nearby host vascular sprouts. This study demonstrates that mature autonomic tissue stimulates the growth of adjacent host vessels when transplanted to undamaged brain surfaces. The anastomosis of nascent host vessels with pre-existing graft vessels is responsible for the rapid re-establishment of circulation within the transplants. A similar mechanism occurs within intraparenchymal grafts, although the rapidity of reperfusion appears to be predicated on the amount of trauma present at the graft site.     

α_2受体阻滞后肾上腺素诱导的心衰病人血小板的聚集功能

先前的研究表明血小板α_2受体变化表征交感神经突触前α_2受体的变化。为了解心衰病人血小板α_2受体功能状况,我们观察了10例Ⅲ、Ⅳ级心功能的心衰病人及10例配对正常人由肾上腺素诱导的血小板聚集率在α_2受体阻滞前后的变化。结果表明肾上腺素诱导的血小板聚集率在两组无显著性差异,但应用α_2阻滞剂Rauwolscine(0.25mg/L)后,0.25,0.5,1.0mg/L E诱导的心衰病人血小板聚集率显著低于对照组,提示血小板α_2受体在心衰时有数量的减少或(和)功能的降低,表征交感神经突触前NE释放的负反馈机制被抑制。     

Transplantation of cultured sympathetic ganglionic neurons into Parkinsonian rat brain: Survival and function of graft

Summary The superior cervical ganglia (SCG) of newborn rats, which had been cultured as expiants for varying periods of time, were transplanted into the striatum of rats with unilateral 6-hydroxydopamine lesions of the nigrostriatal dopamine pathway to examine the survival and functional properties of the sympathetic neurons maintained in long-term culture prior to grafting. In the rats given the SCG cultured in vitro for 2 weeks, apomorphine-induced rotational behaviour was satisfactory reduced. The rats receiving the SCG from 4-week-old cultures showed only modest behavioural changes. The grafting of the SCG cultured for 6 weeks in vitro did not affect the rotational behaviour. These behavioural data corresponded with the histological assessment of the graft survival by use of catecholamine histofluorescence. The present results suggest the critical time period in vitro which might allow the cultured sympathetic neurons to be successfully grafted.     

A neural network confirms that physical exercise reverses EEG changes in depressed rats

The use of an artificial neural network (ANN) system to differentiate the EEG power density spectra in depressed from normal rats was tried. The beneficial effects of chronic physical exercise in reducing the effects of stress and therefore depression was also to be tested in animals by the same method. In this study, rats were divided into 4 groups, subjected to (i) chronic stress (D group); (ii) chronic exercise by treadmill running (EO group); (iii) exercise with stress (ES group) and (iv) handling (C group). The prefrontal cortical EEG, EMG and EOG were recorded simultaneously on paper and the digitized EEG signals were also stored in the hard-disk of a PC-AT through an ADC. After filtering the digitize signals, the EEG power spectra were calculated by an FFT routine. Three successive 4 s artefact-free epochs were averaged. The REM and NREM sleep periods as well as the awake period signals were analyzed separately. The FFT values from each of the 3 states, in the 4 groups of animals were tested by an ANN with 30 first layer neurons and a 2nd layer of a majority-vote-taker. The ANN could distinguish the depressed from the normal rats' EEG very well in REM (99%) sleep, NREM (95%) sleep and awake (81%) states. In most of the cases it identified the exercised rats' EEG as normal.     

淫羊藿苷对人牙髓干细胞神经向分化作用的初步研究

目的 探讨淫羊藿苷（ICA）对人牙髓干细胞（DPSC）神经向分化的作用。方法 分离培养DPSCs后,采用不同浓度ICA(0.01μmol、0.10μmol、1.00μmol、10.00μmol)处理DPSCs。CCK-8法检测ICA对细胞增殖活力的影响,确定其最佳促DPSCs增殖浓度。分别进行细胞形态学观察和Nestin细胞免疫荧光检测。Western blotting检测DPSCs神经向分化相关蛋白Nestin、βⅢ-tubulin及NSE的表达。结果 不同浓度ICA细胞相对活力值比较,差异有统计学意义（P <0.05）,其中以0.10μmol ICA细胞相对活力最高。与对照组比较,ICA组神经球的直径增加（P <0.05）,Nestin荧光强度增强（P <0.05）,Nestin、βⅢ-tubulin、NSE蛋白相对表达量升高（P <0.05）。结论 ICA能够有效促进DPSCs增殖,提高DPSCs神经向分化能力。     

Electromyographic monitoring of profound surgical muscle relaxation during cardiac anesthesia

Quantitative assessment of neuromuscular block produced by large doses of nondepolarizing neuromuscular blocking agents during cardiac surgery is not possible with conventional methods of monitoring. Various posttetanic responses can, however, be elicited, even when no twitch response is present. Posttetanic responses measured by electromyography were used in this study. Twenty-four male patients undergoing coronary bypass surgery were anesthetized with sufentanil plus diazepam. Neuromuscular block was provided either with pancuronium 0.1 mg/kg or with vecuronium 0.07 mg/kg initially and supplemented with small increments when indicated. Neuromuscular block was monitored from the hypothenar muscle. The ulnar nerve was stimulated by train-of-four, with supermposed periodic tetanic stimuli to evoke posttetanic responses, once every 7 to 15 minutes. The tetanically potentiated responses were detectable during 96% ± 3.6 (vecuronium) and during 97% ± 3.7 (pancuronium) of the entire intraoperative period, while the nonpotentiated electromyographic responses were present for less than 50% of the time. The sum (of the amplitudes) of 6 posttetanic responses is significantly (p<0.05) greater than the sum of 6 nonpotentiated responses and than the size of a single-peak posttetanic response when compared with the normal, nonpotentiated responses. Higher-frequency tetanic stimuli (100 or 200 Hz) produced greater posttetanic responses (p<0.05) than did the 50-Hz tetanic stimulus. There were only slight or no significant differences in the degree of posttetanic potentiation between pancuronium and vecuronium either before, during, or after cardiopulmonary bypass. With posttetanic responses, we could detect changes in the level of neuromuscular block that occur during cardiac surgery and that are related to cardiopulmonary bypass, cooling, rewarming, and large doses of corticosteroids and antibiotics. Furthermore, it was not necessary to extend the arm or to use an arm board (on which the hand is immobilized when using mechanical monitoring methods) during cardiac surgery.