牙髓根管感染厌氧菌培养结果分析

从３４例牙髓根管感染中共分离出厌氧菌１１８株，经菌属分类依次为消化链球菌属，拟杆菌属，梭杆菌属，放线菌属，韦荣氏球菌属和珠网菌属，其中前３属为７７株，分离率为６５．３％，这一结果显示该３属细菌与极管感染有密切关系，是牙髓根管感染的优势菌。     

Dorsal root ganglia cocultured with macrophages: an in vitro model to study experimental demyelination

The present investigation introduces an in vitro model to study macrophage properties during demyelination. Rat dorsal root ganglia (DRG) were cultured for obtaining myelinated peripheral nerve fibers. These cultures were exposed to non-resident macrophages. In untreated control cultures, there was no indication of myelin removal by the added macrophages. DRG were exposed to enzymatically generated oxygen radicals using the xanthin/xanthin oxidase or the glucose/glucose oxidase system. Assessment of Schwann cell viability and ultrastructural morphology revealed different patterns of cell cytotoxicity and morphological changes in different experiments. High concentrations caused complete tissue necrosis of the DRG, while low concentrations did not affect either cell viability or ultrastructural morphology. Under intermediate experimental conditions, oxygen radicals caused non-lethal Schwann cell damage leading to Schwann cell retraction and myelin sheath rejection. Myelin lamellae were disrupted and decompacted. These changes were followed by a selective macrophage attack on myelin sheats, resulting in demyelination. Axons, Schwann cells and sensory ganglion cells survived this attack. The specificity of the oxygen radical effects was tested in experiments using the oxygen radical scavengers catalase and superoxide dismutase. Catalase prevented the described effects on cell morphology and subsequently blocked demyelination by non-resident macrophages.Supported by a grant from the Deutsche Forschungsgemeinschaft (DFG) (Br 1274/1-1)     

两种根管弯曲度测量法间数学关系的推导

目的:研究2种根管弯曲度测量法测值(Schneider法的测值为θS,Weine法的测值为θW)间的数学关系。方法:将弯曲根管长轴简化为依次由相切的线段(长度为l1)、圆弧(半径为r、圆心角为θ)、线段(长度为l2)组成的连线,根据2测量法确定简化弯曲根管长轴测量角时不同的定点、连线方式,推导θS、θW间的函数方程以及与l1、l2、r、θ间的数学关系,分析方程与函数图形的特征。结果:θS与θW间存在以下数学关系:(1)tanθS=(1-cosθW ksinθW)/(sinθW kcosθW),k=l2/r;(2)θW/2≤θS≤θW。k取不同值时函数曲线的形态具有不同的特点。θW在0,π的区间内,θS与θW间呈近似的线性关系;k越大,θS越接近θW,k越小,θS越接近θW/2。结论:Schneider法与Weine法测值间存在着复杂的函数关系,根管根尖部直段的长度(l2)与弯曲段曲率半径(r)之比值是影响2种方法测值间差异的重要因素。     

椎管内原发性孤立性纤维性肿瘤临床病理观察(附2例报告)

目的探讨椎管内孤立性纤维性肿瘤的临床病理特征、诊断和鉴别诊断,以期提高对该肿瘤的诊断水平。方法复习2例椎管内原发性孤立性纤维性肿瘤的临床资料,并观察其组织学特征和免疫组化标记。结果2例患者男、女各1例,年龄分别为23岁和32岁,临床表现为局部神经压迫症状。MRI示椎管内髓外硬膜内占位。组织学特征为梭形、卵圆形细胞呈束状、波浪状或旋涡状排列,富于胶原纤维及伴有分支状薄壁血管。细胞未见异型性和核分裂像。免疫组化示瘤细胞Vimentin( ),CD34( ),CD99( ),Bcl-2( ),AACT(-),Actin(-),S-100(-),EMA(-),GFAP(-),CD68(-),CD117(-),SMA(-),NF(-)。结论椎管内原发性孤立性纤维性肿瘤是一种罕见的肿瘤,诊断主要依靠病理形态学及免疫组化,并应与椎管内的其他梭形细胞肿瘤鉴别。     

机械通气患者体位改变插入胃管效果与分析

目的提高有创机械通气患者插入胃管的成功率,减少因反复插管所致的并发症,减轻患者痛苦,提高护士的工作效率。方法把有创机械通气的60例患者,随机分为观察组30例和对照组30例,观察组采取改变常规的“去枕头后仰位”为“抬高床头70°~80°角,头正位”插入胃管,对照组采取常规的去枕头后仰卧位的体位方法插入胃管。结果对照组一次插管成功率为6.66%,观察组一次插管成功率为90%,经统计学分析,差异有显著意义(P<0.01)。结论有创机械通气患者改变常规的“去枕头后仰位”为“抬高床头70°~80°角,头正位”后一次插入胃管成功率明显提高。     

试尖对根管充填质量影响的研究

目的：了解试尖对侧向加压法根管充填质量的影响因素。方法：随机提取我院1998年10月至2004年12月所完成的根管充填病例的X线片1000例，按试尖与未试尖，分别对前牙、前磨牙和磨牙根管充填质量进行分析。结果：在482例未试尖根管充填病例中，前牙、前磨牙和磨牙的适充比例分别为46％、37％和23％，欠充为20％、29％和47％。超充为34％、33％和29％：在518例试尖病例中，前牙、前磨牙和磨牙的适充比例分别为68％、62％和51％，欠充为6％、12％和13％，超充为25％、24％和36％。结论：在侧向加压法根管充填中，试尖可明显改善充填质量。     

Ultrasonography in the detection of cervical incompetency

In 80 pregnancies with clinical and ultrasonic signs of cervical incompetency, the length of the cervix and the thickness of the anterior wall of a lower uterine segment have been evaluated ultrasonically. We have also measured the width of the endocervical canal and studied the prolapse of fetal membranes (with fetal parts) into the endocervical canal. We evaluated these same parameters in 80 healthy pregnancies. The length of the cervix, the thickness of the anterior wall of a lower uterine segment, and the width of the endocervical canal were followed longitudinally in the patients from the 10th to the 36th gestation week. No statistically significant differences between age groups were found. In four age groups at risk for cervical incompetency, cervical lengths and wall thickness were significantly different (p less than 0.001) from those in comparable controls. Forty-five percent of the patients in the at-risk group, with cervical cerclage, delivered at 37.3 (range: 32 to 41) weeks and 6.25% of pregnancies ended in abortion when the amniotic membrane herniated into the cervical canal, with or without some part of the fetus.     

The use of coaxially aligned freeze-thawed skeletal muscle autografts in the repair of the cauda equina — in the sheep

Summary The aim was to develop a model for study of nerve regeneration in nerve roots above the level of the dorsal root ganglion and to investigate the use of freeze-thawed muscle autografts for repair of nerve roots at this level.Four adult sheep were used for the experiment. A laminectomy was performed at the lumbosacral junction and the S2 root identified. Both the dorsal and ventral S2 roots were divided unilaterally within the dura and a freeze-thawed muscle graft was inserted into the nerve gap.When assessed at 6 months an action potential was recordable from the ventral root in one sheep. Histological examination of the nerve roots showed evidence of regeneration across the graft in the ventral roots of all the sheep and the dorsal roots of some.This preliminary work indicates a capacity for regeneration of the cauda equina and that freeze-thawed muscle can support this. It provides a useful model for further study of nerve root repair.     

大鼠肺微血管和肺泡铸型的扫描电镜观察

用扫描电镜观察以甲基丙烯酸甲酯灌注鼠的肺微血管和肺泡。胸膜下毛细血管较稀疏,网孔粗大。毛细血管部分成锐角折返,亦可见毛细血管盲端。肺泡隔毛细血管均成扁平状膨大,且相互吻合成单层密集网。肺泡铸型为大小不等、不规则的多面体,表面可见肺泡Ⅱ型细胞核之压迹。两肺泡之间可见呈桥式连接的肺泡孔,亦可见部分呈三通管样相连。