右心室流出道与右心室心尖部起搏对心室收缩同步性和心功能的影响

目的研究右心室流出道(right ventricular outflow tract,RVOT)间隔部和右心室心尖部(right ventricularapex,RVA)起搏对心脏收缩同步性、收缩功能的影响,探讨RVOT间隔部起搏的意义。方法 50例病态窦房结综合征患者分为RVOT组(n=25)和RVA组(n=25),起搏器置入1个月后通过调整房室间期使心室节律全部为起搏节律或房室结自身下传节律,观察起搏参数,并行超声心动图检查。结果RVOT组与RVA组电极导线植入时间、X线曝光时间比较,差异无统计学意义(P>0.05)。全部患者未出现植入并发症。两组随访1个月时起搏参数比较,差异无统计学意义(P>0.05)。RVOT组和RVA组起搏后的QRS波时限较前明显增宽,差异有统计学意义[RVOT组:(135±8)ms vs.(88±8)ms,P<0.001;RVA组:(154±8)ms vs.(90±6)ms,P<0.001]。RVA组起搏后QRS波时限较RVOT组增宽更为明显,差异有统计学意义(P<0.001)。两组起搏后室间机械延迟(interventricularmechanical delay,IVMD)和室间隔-左心室后壁收缩运动延迟时间(septal-to-posteriowall motion delay,SPWMD)较起搏前均显著增加,差异有统计学意义(P<0.001)。RVA组起搏后IVMD和SPWMD绝对值较RVOT组显著延长,差异有统计学意义[IVMD:(38±7)ms vs.(24±5)ms,P<0.001;SPWMD:(118±21)ms vs.(60±11)ms,P<0.001]。两组左心室舒张末内径及左心室射血分数比较,差异无统计学意义(P>0.05)。结论右心室起搏会造成心室收缩不同步,RVOT起搏对心室收缩不同步的影响较RVA起搏小,提示RVOT起搏是较为生理的起搏位点。     

眶尖部的断层影像解剖学研究

①目的　通过眶尖部结构的断层影像解剖研究 ,为鼻内镜下眶尖部手术提供可靠的解剖学数据 ,减少手术并发症。②方法　随机选取 30例成人尸头进行CT扫描 ,对前鼻棘至眶尖部各结构的距离、侧偏角、视神经管及眶上裂各径线长度、毗邻关系等进行断层影像解剖观测。并将CT扫描图像与断层切片进行对照。③结果断层影像测量前鼻棘至视神经管眶口、颅口内侧壁的距离分别为 (70 .35± 4 .93)、(72 .76± 5 .0 3)mm ,侧偏角分别为9.6 5°± 1.30°、5 .4 4°± 0 .86°。视神经管内侧壁中部最薄 ,视神经管中部为视神经管最狭窄的部位。④结论以FV平面作为轴位扫描基线 ,结合水平及冠状位CT图像进行分析 ,有利于眶尖部结构的准确定位     

不同终板准备方法对ProDisc-C颈椎人工椎间盘假体稳定性的影响

目的:探讨不同颈椎终板准备方法对颈椎人工椎间盘置换术后金属-骨界面刚度的影响,了解终板准备方法与人工椎间盘假体稳定性的关系。方法:取6具新鲜成人尸体颈椎标本,分离出C3～T1共35个椎体(1例C6～C7融合),剔除每个椎体上下面的椎间盘组织,显露出骨性终板,分为:去终板组17个,完全去除骨性终板;保留终板组18个,完整保留骨性终板。在所有椎体的上面安放相应大小的颈椎人工椎间盘(ProDisc-C)后用MTS-858生物力学实验机进行疲劳测试和屈服测试,得到金属-骨界面的刚度、位移和最大屈服压力,从其中1具颈椎标本取出4个椎体(每组各2个)切片行HE染色后用光镜观察金属-骨性界面。结果:疲劳前测试金属-骨界面刚度去终板组为1470±180N/mm,高于保留终板组的1260±170N/mm(P<0.0001);疲劳后测试两组刚度均有上升,去终板组刚度为1990±110N/mm,仍高于保留终板组的1680±140N/mm(P<0.0001)。疲劳前测试两组的终板位移分别为0.45±0.09mm和0.41±0.10mm,无显著性差异(P=0.15),疲劳后测试去终板组位移0.53±0.12mm小于保留终板组的0.66±0.14mm(P=0.005)。去终板组最大屈服压力为1110±350N,略小于保留终板组的1250±230N,但无显著性差异(P=0.27)。组织切片显示去终板组金属-骨界面贴合良好,而保留终板组金属-骨界面有明显的缝隙。结论:不同的终板准备方法会影响到假体金属-骨界面的刚度和稳定性。去终板组金属-骨界面的刚度和稳定性优于保留终板组,良好的金属-骨界面接触是颈椎人工椎间盘假体稳定的关键因素之一。     

累及眶尖的海绵窦肿瘤的手术探讨

目的讨论累及眶尖的海绵窦肿瘤手术方法及相关解剖。方法22例全部采用额颞弧形切口，翼点人路。当肿瘤位于视神经外侧或海绵窦外侧壁时，选择颞部偏大的切口。取下骨瓣，磨除蝶骨嵴，剪开硬膜，分开外侧裂。依据肿瘤的位置用微钻磨除前床突和视神经管上壁。选择肿瘤突出部位切开海绵窦外侧壁或眶筋膜，分块切除肿瘤。结果22例肿瘤中，17例全切，3例近全切，1例大部分切除，1例活检。结论详细了解海绵窦和眶尖肿瘤的外科解剖是达到其外科切除的良好结果所必需。     

根管长度电测法准确性的研究

目的探讨根尖炎症及根管干、湿状态对电测法测量根管工作长度准确性的影响.方法临床上随机选择拟做根管治疗的120颗牙共140个根管进行研究,其中无根尖炎和有根尖炎者分别为56、84个根管.常规根管清理后,采用ROOT ZX根管长度电测仪在干、湿两种根管状态下进行根尖位置的探测,根管充填后,根据X线片影像确定根管长度电测法的准确性. 结果根管充填后X线片显示恰填者104个(74.29%)根管,欠填者6个(4.28%)根管,超填者30个(21.43%)根管.干燥的根管较湿润的根管更易测得准确的根管工作长度(P<0.01);有、无根尖炎其测量结果准确性无显著性差异(P>0.05).结论根管长度电测法是一种准确度高、操作简便且实用的确定根管工作长度的方法.根尖炎症对其测量根管工作长度的准确性无明显影响,干燥的根管较湿润的根管更易测得准确的根管工作长度.     

颌突外胚间充质干细胞参与根尖缺损修复作用的研究

目的:探讨颌突外胚间充质干细胞参与根尖缺损修复的作用。方法:将外胚间充质干细胞复合锻烧骨后移植入大鼠根尖缺损处,以大鼠成纤维细胞复合煅烧骨、空白煅烧骨作为对照,1月后取材,经HE染色鉴定。结果:实验组修复的效果明显好于对照组,形成牙髓牙骨质样物。结论:提示移植的外胚间充质干细胞向该局部组织细胞分化,并参与根尖组织的修复。     

Presynaptic snake β-neurotoxins produce tetanic fade and endplate potential run-down during neuromuscular blockade in mouse diaphragm

The present study investigated the ability of a number of presynaptic snake neurotoxins (snake β-neurotoxins) to produce nerve-evoked train-of-four fade, tetanic fade and endplate potential run-down during the development of neuromuscular blockade in the isolated mouse phrenic-hemidiaphragm nerve-muscle preparation. All the snake β-neurotoxins tested, with the exception of notexin, produced train-of-four and tetanic fade of nerve-evoked isometric muscle contractions. Train-of-four fade was not present during the initial depressant or facilitatory phases of muscle tension produced by the snake β-neurotoxins but developed progressively during the final depressant phase that precedes complete neuromuscular blockade. The ‘non-neurotoxic’ bovine pancreatic phospholipase A₂ and the ‘low-toxicity’ phospholipase A₂ from Naja naja atra venom failed to elicit train-of-four fade, indicating that the phospholipase activity of the snake β-neurotoxins is not responsible for the development of fade. Intracellular recording of endplate potentials (EPPs) elicited by nerve-evoked trains of stimuli showed a progressive run-down in EPP amplitude during the train following incubation with all snake β-neurotoxins except notexin. Again this run-down in EPP amplitude was confined to the final depressant phase of snake β-neurotoxin action. However when EPP amplitude fell to near uniquantal levels (<3mV) the extent of toxin induced-fade was reduced. Unlike postjunctional snake α-neurotoxins, prejunctional snake β-neurotoxins interfere with acetylcholine release at the neuromuscular junction during the development of neuromuscular blockade. This study provides further support for the hypothesis that fade in twitch and tetanic muscle tension is due to an underlying rundown in EPP amplitude resulting from a prejunctional alteration of transmitter release rather than a use-dependent block of postjunctional nicotinic receptors. Received: 5 May / Accepted: 16 July 1997     

Antigenic difference of acetylcholine receptor between single and multiple form endplates of human extraocular muscle

The acetylcholine receptor (AChR) of human extraocular muscle (EOM) has been studied by the immunological method using anti-AChR antibodies obtained from the sera of patients with myasthenia gravis (MG) of ocular type, whose symptoms have been restricted to EOM. Those antibodies could distinguish the AChR of multiple (en grappe) form endplates from that of single (en plaque) form endplates. This result indicates the antigenic difference of AChR between those two forms of endplates of human EOM.     

Prognostic significance of axillary node and infraclavicular lymph node status after mastectomy

AIMS: The American Joint Committee on Cancer staging system for breast carcinomas has been revised. According to this revised staging system, metastasis to infraclavicular lymph nodes and number of positive axillary nodes have prognostic significance and a new stage, stage IIIC, has been introduced. The aim of this study is to investigate the association of positive axillary nodes by level and number with survival and stage migration between the old and the new stages in a large series of mastectomy patients. METHODS: Data from 1277 consecutive breast cancer patients treated by mastectomy were studied, retrospectively. Prognostic value of number of positive axillary nodes and entirely invasion of apex axillary nodes were analysed. Survival curves were generated by Kaplan-Meier method, and multivariate analysis was performed by Cox proportional hazard model. RESULTS: Five-year survival rates for metastasis to axillary level III and for stage IIIC breast cancer were 35.4 and 38.2%, respectively. Metastases to apex axillary nodes, 4-9 and 10 or more positive lymph nodes were found to be adverse and independent prognostic factors for survival in lymph node positive patients. CONCLUSION: Invasion of infraclavicular nodes and 4-9 and > or =10 positive axillary lymph nodes were independent predictors for survival in node positive breast carcinomas in this series. Patients with the new stage IIIC had the worst survival among breast cancer patients.