西宁地区健康小儿窦房结功能测定的初步探讨

应用食道心房调博缩测定健康小儿窦房结功能，以了解西宁地区正常数值与平原地区进行对比。选择２７例健康小儿，将Ｆ６二级电极导管从鼻腔送入，定位地食道心电图最大正负双相Ｐ波处，采用苏州东方电子仪器厂生产的ＤＦ－３Ａ型心脏电生理治疗仪进行检查，从而作出诊断。     

Modification of DiFrancesco-Noble equations to simulate the effects of vagal stimulation onin vivo mammalian sinoatrial node electrical activity

We present a new mathematical model for vagal control of rabbit sinoatrial (SA) node electrical activity based on the DiFrancesco-Noble equations. The original equations were found to be unstable, resulting in progressive cycle by cycle depletion or accumulation of ions in intra- and extracellular compartments. This problem was overcome by modifying the maximum Na−K pump current and the time constant for uptake of intracellular calcium. We also included a formulation for the acetylcholine (ACh)-activated potassium current which was consistent with experimental data. This formulation was based on kinetics first proposed by Osterrieder and later modified by Yanagihara. The resulting model exhibits cycle-cycle ionic stability, and includes an ACh-activated potassium current which accurately reproduces experimentally observed effects of vagal stimulation on both the membrane potential and its timederivative. Simulations were performed for both brief-burst and prolonged vagal stimulation using simplified square wave profiles for the concentration of ACh in the synaptic cleft space. This protocol permits the isolation of cardiac period dynamics caused by changes in membrane potential and intra- and extracellular ionic concentrations from those caused by other mechanisms including the dynamics of ACh release, diffusion, hydrolysis and washout. Simulation results for the effects of brief-burst single cycle stimulation on the cardiac period agree closely with experimental data reported in the literature, accurately reproducing changes in membrane potential and the phasic dependency of the response to the position of vagal stimulus bursts within the cycle. Simulation of the effects of prolonged vagal stimulation accurately reproduced the steady-state characteristics of heart period response, but did not yield the complex multimodal dynamics of the recovery phase, or the pronounced post vagal tachycardia observed experimentally at the termination of the stimulus. Our results show that the major chronotropic effects of vagal stimulation on the SA cell membrane can be explained in terms of the ACh-activated potassium current. The effects of this membrane current however are generally fast acting and cannot contribute to any long lasting dynamics of the cardiac period response. The modified DiFrancesco-Noble model presented in this article provides a valuable theoretical tool for further analysis of the dynamics of vagal control of the cardiac pacemaker.     

等速离心训练对肩关节内外旋肌的肌力平衡及神经肌肉控制能力的影响

背景 肩关节内外旋肌肌力失衡会增加肩部运动损伤的风险,研究等速离心训练(IET)能否提高肌力平衡并改善神经肌肉控制能力具有重要的损伤预防意义。目的 探讨IET对健康青年人肩关节内外旋肌的肌力平衡及神经肌肉控制能力的影响。方法 2020年12月至2021年11月在复旦大学附属中山医院招募32例健康青年志愿者为研究对象,随机将其分为试验组(n=16)和对照组(n=16)。试验组接受4周IET,对照组接受4周连续被动运动训练(2次/周)。采用Biodex System 4 Pro多关节等速肌力测试与训练系统(美国Biodex公司)对两组研究对象的优势侧肩关节内、外旋肌群进行训练干预,分别在60(°)/s、120(°)/s速度下进行,干预前1周、干预结束后1周对两组肩关节内外旋肌的功能性比率(FR)、加速时间(AT)和达峰力矩时间(TPT)进行评估并比较。结果 试验组全部完成了4周的训练干预和评估,对照组2例中途退出。最终共30例研究对象数据纳入统计学分析。在60(°)/s和120(°)/s速度下,试验组干预后FR高于对照组(P<0.001),试验组干预后FR高于干预前(配对t检验：t<...     

胃癌术前淋巴结转移评估方法研究进展

胃癌在我国的发病率及病死率较高,目前,手术仍然是胃癌的主要治疗方式。术前诊断淋巴结转移对于胃癌手术方式的选择有着重大意义。目前,临床中对于胃癌术前淋巴结转移的诊断尚没有金标准。本文对胃癌术前淋巴结转移评估方法的研究进展进行综述。     

Reliability of Transesophageal Pacing in the Assessment of Sinus Node Function in Patients with Sick Sinus Syndrome

The purpose of this study was to find out whether transesophageal pacing could be utilized for assessment of sinus node function in patients with sick sinus syndrome (SSS). In 17 patients with SSS (study group) we compared the results of sinus node tests obtained both in the basal state and after pharmacological autonomic blockade by endocavitary stimulation and, 24 hours later, by transesophageal pacing. In another group of 17 patients with SSS (control group), we compared the results obtained by two endocavitary studies. In "study group", sinus cycle length (SCL) and corrected sinus node recovery time (CSRT) did not show significant differences between the two studies both in the basal state and after autonomic blockade, whereas sinoatrial conduction time (SACT) was more prolonged during esophageal pacing (P less than 0.01). In "control group", sinus node measures did not show significant differences between the two studies. In the "study group," the following coefficients of correlation were obtained in the basal state; SCL, r = 0.65, CSRT, r = 0.57, SACT, r = 0.52 and after autonomic blockade: SCL, r = 0.95, CSRT, r = 0.62 and SACT, r = 0.53. In the basal state, the correlation for SCL and CSRT between the two studies was lower in the "study group" than in the "control group" (P less than 0.05), whereas after autonomic blockade the correlation for sinus node measures did not show significant differences between the two groups of patients. These data suggest that transesophageal study influences the autonomic tone regulating the sinus node; however, it is not responsible for important variations in sinus node measures.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidural compression from metastatic tumor with resultant paralysis

To determine the value of the usually given urgent palliative radiotherapy in paraplegic patients with epidural compression from metastatic tumor, 20 consecutive cases treated between 1981 and 1986 were retrospectively analyzed. Bronchogenic and prostatic carcinoma were the more common extraspinal sources of metastasis. Epidural metastasis involved the thoracic spine in most cases. The onset of neurological symptomatology was frequently within two weeks prior to hospitalization. The majority of the subjects received at least 3000 cGy given in 10 to 15 fractions. Symptomatic (pain relief) response rate was 78 (7/9) percent. The observed period of survival averaged 2.5 months after treatment. This study reaffirmed the little chance for recovery of lost limb(s) motor function. None of the patients (most of whom were paraplegic from two to 90 days pre-irradiation) became ambulatory including the two in whom irradiation was administered within 24 hours from the onset of paraplegia.     

Intraoperative frozen section examination of axillary sentinel lymph nodes in breast cancer

The study presents the results from intraoperative frozen section assessment of axillary sentinel lymph nodes (SLNs) in breast cancer. Routine histological frozen sections from one level were used, two sections stained with haematoxylin and eosin. Immunohistochemistry for cytokeratins was applied to the permanent SLN paraffin sections only. Axillary dissection was performed on all SLN-positive cases regardless of the size of the metastatic deposits. With a detection rate of 83%, 272 patients entered the study over a period of 46 months. A total of 61 cases were SLN positive by frozen section analysis. The paraffin sections gave an additional 23 SLN-positive cases. The false-negative rate for frozen sections was then 27% (23/84). Micrometastases were found in 28 of 84 cases, and macrometastases in 56. The false-negative rate of frozen sections for micrometastases was 71% (20/28), and for macrometastases 5% (3/56). A total of 73% (61/84) of the patients underwent axillary surgery as a one-step procedure.     

Effect of moderate exercise on salivary immunoglobulin A and infection risk in humans

The incidence of upper respiratory tract infections (URTI) and salivary immunoglobulin A concentrations [IgA_s] of nine individuals were examined during 12 weeks of moderate exercise training, and compared to ten sedentary controls. Changes in maximal oxygen uptake were assessed at initial, mid-point and final evaluations (T1–3), while changes in [IgA_s] and salivary immunoglobulin concentration-salivary albumin concentration ratio ([IgA_s]:[Alb_s]) were monitored at T1 and T3. During the 12 week period, symptoms of URTI were self-recorded daily. During the period of training the level of fitness significantly increased (P<0.05) in the exercise group. The number of days recording symptoms of influenza, but not of cold, and total light URTI symptoms was significantly reduced in the exercise group during the last weeks of training. A significant increase in [IgA_s] and in [IgA_s]:[Alb_s] was found in the exercise group after training. Both [IgA_s] and [IgA_s]:[Alb_s] were significantly related to the number of days showing symptoms of influenza (P<0.01) and the total number of days of sickness (P<0.05). These data provide quantitative support for the belief that regular, moderate exercise results in an increased [IgA_s] at rest and [IgA_s]:[Alb_s], which may contribute to a decreased risk of infection. Electronic Publication     

Measure of association between selenium status and sepsis in cattle

Odds ratio was used to evaluate relationship between sepsis in cattle less than 1 year old and mastitis in cows and erythrocyte glutathione peroxides (GSH-PX) activity as an indicator of selenium status. Data were from 178 blood samples collected from referred cases to Urmia University, Veterinary Teaching Hospital. Low activity of GSH-PX was significantly associated with higher odds of developing sepsis (P=0.005) in young cattle and mastitis (P=0.044) in adult cows. The odds ratios for the low activity of GSH-PX on incidence of sepsis and mastitis were 4.74 and 3.95, respectively. Selenium deficiency was associated with sepsis in young cattle and mastitis in cows, i.e., cattle with low activity of erythrocyte GSH-PX were at increased risk of sepsis and mastitis.     

The sustained inward current in sino-atrial node cells of guinea-pig heart

 Single myocytes were dissociated from the sino-atrial (SA) node of guinea-pig hearts. Only a quite small fraction of the cell population showed spontaneous action potentials and these cells were characterized by the presence of the hyperpolarization-activated cation current I _f , the delayed rectifier K⁺ current I _K and the L-type Ca²⁺ current I _Ca,L as well as by the absence of both the transient outward current I _to and the inward rectifier K⁺ current I _K,1. After blocking I _f and I _K, depolarizing pulses from –80 mV revealed a large nicardipine-sensitive late current (NSLC). The NSLC was scarcely affected by decreasing extracellular [Ca²⁺] ([Ca²⁺]_o) from 1.8 to 0.1 mM, while it was decreased significantly by depleting [Na⁺]_o, differently from I _Ca,L. NSLC was blocked by nicardipine and was increased by Bay K 8644. NSLC was increased by isoprenaline and the additional application of acetylcholine reversed the increase of this current. We conclude that NSLC is largely composed of I _st described in the rabbit SA node pacemaker cells, and that I _st is unique for the pacemaker cells in mammalian SA node cells. Most of the quiescent cells showed neither I _f nor I _st. Received: 22 July 1996 / Received after revision: 30 September 1996 / Accepted: 9 October 1996