Shaping ability of the M4 handpiece and Safety Hedstrom Files in simulated root canals

The aim of this study was to assess the shaping ability of the M4 reciprocating handpiece and Safety Hedstrom files in simulated canals. A total of 40 simulated canals of various angles and positions of curvature were prepared with an M4 handpiece using Safety Hedstrom files oriented with the ground, flattened surface towards the inner aspect of the curve. A standard regimen was adopted throughout. Pre- and post-operative longitudinal images of the canals were taken with a video camera and stored and manipulated in a computer with image analysis software. The presence of canal aberrations and the amount and location of resin material removed as a result of preparation were determined from composite images of superimposed pre- and post-operative views. Preparation time varied significantly (P<0.001) between the canal types; overall, 20° canals were prepared more quickly than 40° canals. Zips and elbows were observed in 16 out of the 40 canals with most (11) being created in 40° specimens. Ledges were found in 19 canals and perforations in only 1. There were no significant differences between canal shapes for these aberrations. Excessive removal of material from the inner aspect of the canal at the curve to create a danger zone was found in 20 canals, but only in those with 40° curves. Significant differences in total canal width between the canal types were seen at the zips (P<0.05), elbows (P<0.05) and danger zones (P<0.001). Transportation at the danger zones varied significantly (P<0.001) between canal types. Under the conditions of this study, the M4 handpiece and Safety Hedstrom files created hour-glass preparations in a substantial proportion of canals. In reality, the Safety Hedstrom file with its one flattened surface was ineffective at reducing removal of material along the inner aspect of canal curves in severely curved specimens and clearly has the potential to create strip perforations in teeth.     

Movement-related potential measures of different modes of movement selection in Parkinson's disease

Movement-related potentials were recorded preceding self-paced voluntary movements in patients with Parkinson's disease and in healthy subjects of the same age group. We compared the Readiness Potential preceding joystick movements in a fixed direction and preceding joystick movements in freely selected directions. In normal subjects the Readiness Potential amplitude was higher preceding freely selected movements than preceding movements in a fixed direction. The Readiness Potential in Parkinson patients failed to be modified by the different modes of movement selection. The modulation of the Readiness Potential by different ways of preparing for movement might be due to the supplementary motor area (SMA) being more strongly engaged by tasks requiring internal control of movements than by tasks that are externally structured. The results suggest that this task-dependent variation of SMA activity is reduced in Parkinson's disease. A failing capacity to adapt SMA activity to different task demands has previously been suggested by evidence from positron emission tomography studies using similar tasks.     

肾上腺皮质腺癌的诊断与治疗

目的 探讨肾上腺皮质腺癌的早期诊断、手术及围手术期处理。方法 回顾分析了1990年至2001年间31例肾上腺皮质腺癌临床资料．并与1978年至1989年同种病例作比较。结果 近10年患者病理分期更趋向早期，更易行根治性切除，5年的存活率明显提高。结论 影像学的发展，使患者易早期诊断；围手术期的充分准备是减少手术并发症及死亡率的关键。     

Retrospective review of the preoperative biliary and gastrointestinal evaluation for gastric bypass surgery

BACKGROUND: The purpose of this study was to analyze the frequency and results of preoperative biliary and gastrointestinal (GI) evaluation of patients undergoing Roux-en-Y gastric bypass (RYGB). METHODS: Retrospective review of the preoperative evaluation of 144 consecutive RYGB patients. RESULTS: Cholecystectomy had already been performed in 43 (30%) patients; 22% of those patients with an intact gallbladder had cholelithiasis. Ten patients (7%) had an upper GI x-ray (UGI), and 94 patients (65%) had an esophagogastroduodenoscopy (EGD). Abnormalities were found in 40% of the UGIs and 84% of the EGDs. A total of 96 patients (67%) were tested for Helicobacter pylori; 11% were positive. Twenty-one patients (15%) underwent preoperative colonoscopy; 48% were abnormal, but most of the abnormalities were not clinically significant. Three patients had barium enema x-ray, which was normal in all cases. CONCLUSIONS: The preoperative biliary and GI evaluation of bariatric surgery patients should include a routine ultrasound of the gallbladder. Routine preoperative EGD will detect a significant number of abnormalities that should be treated, but should rarely alter the bariatric surgical procedure or result in denial of bariatric surgery. Many abnormalities will be asymptomatic. Patients should be routinely screened for H. pylori and, if positive, treated before bariatric surgery. Lower GI evaluation should be performed selectively based on the patient's symptoms, physical findings, and guidelines for colorectal cancer and polyp screening.     

多排螺旋CT椎管造影术前评价腰椎间盘突出症

在脊柱外科手术中腰椎间盘突出症的比例越来越高。而正确的术前评价是保证手术疗效良好的因素之一。本组选择临床诊断腰椎间盘突出症39例,并经低毒低渗非离子型造影剂椎管造影及多排螺旋CT椎管造影(myelography and multi-spiral CTscanning,MSCTM)检查,现就其在腰椎间盘突出症     

微波干燥法对腊叶标本压制的实验研究

目的：寻求一种不受气候条件影响而能成功制作腊叶标本的新技术。方法：采用微波干燥法，即用微波炉，由创制的直径31cm瓦楞纸板、吸水纸与玻璃皿组成的压制程序进行微波干燥。结果：微波干燥法可用于腊叶标本压制，且优于传统的常规腊叶标本压制方法。结论：本研究为腊叶标本的制作提供了一个新方法，收到了便捷、高效、且保色的理想效果。     

离体肺组织切片的制备和孵育

目的建立一种简便有效的离体肺组织切片孵育方法。方法利用肺组织精细切片技术制备肺组织切片 ,以 0 .5mLKrebs Henseleit(K H)缓冲液作为孵育液 ,在 37℃培养箱内分别孵育 1、2、3、4h ,测定肺片的四甲基偶氮唑盐 (MTT)比色、乳酸脱氢酶 (LDH)释放率和三磷酸腺苷 (ATP)含量 ,以反映肺组织活性。结果肺片在 37℃培养箱内孵育 1、2、3、4h后MTT比色、LDH释放率和ATP含量均无统计学差异 (P >0 .0 5 )。结论应用 0 .5mLKrebs Henseleit(K H)缓冲液作为孵育液、在 37℃培养箱对肺片进行孵育时组织活性没有明显变化 ,可作为一种简便有效的孵育方法用于离体肺片研究     

备用根大鼠脊髓后角提取液中神经营养活性组分的分离及生物活性测定

制作备用根大鼠脊髓后角提取液，取其分子量大于10kD的组分进行SDS-聚丙烯酰胺凝胶电泳分析，发现手术侧和非手术侧的电泳区带数目大致相同，但手术侧样品的第四条蛋白质区带扫描的吸收峰面积百分比大于非手术侧样品的第四条区带，两者在量上可能有差别。将手术侧样品经交联葡聚精G-75凝胶层析，得到两个洗脱峰．第一峰洗脱液有促进体外培养的背根节神经元存活及其突起生长的作用，其电泳分析显示4条主带，分子量在40～80kD之间．实验结果提示部分去传入纤维支配的脊髓后角组织含有神经营养活性物质，该物质的分子量约在40～78kD之间．     

The isolated spinal cord-skin preparation of the newborn rat and effects of some algogenic and analgesic substances

We have developed an isolated spinal cord-skin preparation of the newborn rat. The spinal cord together with a piece of skin connected to the cord by the saphenous nerve was isolated from 1- to 4-day-old rats and separately superfused with artificial cerebrospinal fluid in two neighbouring chambers. Potentials were recorded extracellularly from the third lumbar ventral root. Application of capsaicin (0.5-2 μM) or KCl (60–350 mM) with brief pressure pulses to the perfusion bath of the skin evoked a depolarizing response of 20- to 40-s duration in the ventral root. The response was depressed by [Met⁵]enkcphalin (0.03–3 μM). morphine (0.1–2 μM) and a tachykinin antagonist, [D-Arg¹,D-Trp^7,9,Leu¹¹] substance P (spantide), 1–10 μM), applied to the spinal cord by superfusion, whereas the response was augmented by centrally administered calcitonin gene-related peptide (0.1–0.2 μM) or bicuculline (0.5–1 μM).     

复合膳食纤维对大鼠体内脂质过氧化作用的影响

制备复合膳食纤维 (dietaryfiber,DF) ,并分别探讨复合、混合及三种单一的DF对高脂血症大鼠体内脂质过氧化作用的影响。选健康、断乳Wistar大鼠 6 4只 ,按体重随机分为 8组 ,用高脂饲料诱发高脂血症的同时 ,分别添加 10 %的DF :纤维素 (B组 )、果胶 (C组 )、海藻酸钠 (D组 )、纤维素 -果胶复合物 (E组 )、纤维素 -海藻酸钠复合物 (F组 )、纤维素 -果胶混合物 (G组 )、纤维素 -海藻酸钠混合物 (H组 ) ,以单纯的高脂饲料组为对照组 (A组 ) ,观察各种DF对大鼠的生长发育及脂质过氧化作用的影响。结果显示 :1、添加 10 %的各种DF不影响大鼠的生长发育。 2、各种DF皆可显著升高血清超氧化物歧化酶 (SOD) (P <0 0 1)、谷胱甘肽过氧化物酶 (GSH Px)活性 (P <0 0 1) ,降低丙二醛 (MDA)水平 (P <0 0 5 ,B、D组除外 ) ,提高红细胞膜的流动性 (P <0 0 5 ) ,以复合物、混合物效果为明显。 3、各种DF可不同程度地增加粪重和粪脂排出量 (P <0 0 5 ,D组除外 ) ,以复合物、混合物为明显。提示各种DF皆可不同程度地降低大鼠体内脂质过氧化作用 ,提高红细胞膜的流动性 ,其中可溶性DF效果优于不可溶性DF ,而复合、混合DF的效果又优于单一的DF ,且以复合物效果为佳