离体牙上釉珠的观测与临床意义

本文从12379枚离体牙上观测了釉珠的发生率、发生部位、形态、直径大小。结果釉珠的发生率为2.49％,以上颌第三磨牙发生率最高,下颌第一磨牙次之。最常发生的部位是在冠颈部的根分叉处,上颌磨牙的釉珠多呈园形,下颌磨牙釉珠多呈梭形。釉珠最大直径为3.2mm,最小为0.5mm,平均为1.56mm。结合文献认为釉珠是一种牙齿形态发育异常,它对牙周病的发生、发展、治疗与预后有重要影响,口腔科医师对这种牙齿形态变异应予以重视。     

Bone mineral density testing in healthy postmenopausal women. The role of clinical risk factor assessment in determining fracture risk.

The ease of measurement and the quantitative nature of bone mineral densitometry (BMD) is clinically appealing. Despite BMD's proven capability to stratify fracture risk, data indicate that clinical risk factors provide complementary information on fracture susceptibility that is independent of BMD. Methods to quantify fracture risk using both clinical and BMD variables would have great appeal for clinical decision-making. We describe a procedure for quantifying hip fracture risk (5-yr and remaining lifetime) based on (1) the individual's age alone (base model, assuming average clinical risk factors and bone density), (2) incorporation of multiple patient-specific clinical risk factor data in the base model, and (3) incorporation of both patient-specific clinical risk factor data and BMD results.     

Magnetic resonance imaging confirmation of resolution of periodontoid pannus formation following C1/C2 posterior transarticular screw fixation.

Chronic odontoid fractures are considered unstable spinal lesions. Chronic instability in this region leads to the development of an inflammatory pannus, which can progress resulting in spinal cord compression radiographically and a myelopathy syndrome clinically. In this report we document three cases of reversal of pannus after C1/C2 transarticular screw fixation of an unstable odontoid fracture. Three patients were identified with chronic odontoid fractures and spinal cord compression due to periodontoid pannus formation. All patients presented with a progressive myelopathy syndrome. All patients underwent preoperative and postoperative magnetic resonance imaging (MRI) of the craniovertebral junction. C1/C2 transarticular screw fixation was performed for stabilization of C1/C2. Postoperatively there were no complications. Postoperative MRI at 6 months demonstrated resolution of the ventral pannus. Moreover, all patients exhibited improvement of preoperative neurological deficits. MRI is the imaging technique of choice for diagnosis and follow-up of patients with chronic odontoid fractures and ventral pannus. C1/C2 transarticular screw fixation provides a viable method for spinal stabilization in this region. In addition, stabilization can result in resolution of inflammatory pannus formation secondary to instability of the C1/C2 articulation.     

在"医学教育国际标准研讨会"上的致辞

<西太平洋地区本科医学教育指导原则>为医学院校提供了基准和质量改进的努力方向,并将有助于实现可持续的课程改革.本次会议将是中国在改善本科医学教育质量上迈出的重要一步.世界卫生组织愿与中国政府合作并提供支持.     

转hCTLA4Ig树突状细胞诱导T细胞免疫耐受的实验研究

目的　通过逆转录病毒载体将人CTLA4Ig转染DCs ,探讨转人CTLA4Ig(hCTLA4Ig)树突状细胞 (DCsRev)诱导T细胞免疫耐受的可能性。方法　通过重组逆转录病毒将目的基因hCTLA4Ig转染到大鼠骨髓来源的DCs中 ,通过流式细胞检测目的基因hCTLA4Ig表达及DCs表面分子的改变 ;通过混合淋巴细胞反应 (MLR)检测DCsRev抑制T细胞免疫反应的能力。 结果　重组逆转录病毒转染DCs的最大效率为 91 2 5 % ;在功能上 ,DCsRev不但丧失了刺激MLR的能力 ,并且能够强烈抑制MLR中反应T细胞的增殖 ,而且抑制率与加入DCsRev的数量和DCsRev预处理反应T细胞的时间长短有关。具体来说 ,DCsRev数量在 10 3 ～ 10 4之间时 ,抑制率与剂量呈正相关 ,最高为 71 96%。而当DCsRev数量达到 5× 10 4抑制率下降为 5 9 2 %。在 12～ 48h之间 ,随着预处理时间的延长 ,抑制率却不断下降 ,预处理 12h抑制率最高 ,为 99 6%。但不做预处理 ,在反应开始时同时加入DCsRev ,则抑制率明显降低 ,仅为 5 9 2 %。对腹腔注射DCsRev大鼠脾T淋巴细胞体外分析表明 ,DCsRev也能在动物体内诱导耐受 ,但这种免疫耐受状态不能维持终身。结论　通过逆转录病毒载体将人CTLA4Ig转染DCs,不但DCs表面CD86分子被CTLA4Ig有效的封闭 ,并且能够诱导抗原特异性T细胞的免疫耐受     

Comparison of ThinPrep versus conventional smear cytopreparatory techniques for fine-needle aspiration specimens of head and neck masses.

OBJECTIVES: Diagnostic accuracy of the ThinPrep process (Cytyc, Boxborough, MA) was compared with that of conventional (smear) cytopreparation for fine-needle aspiration (FNA) of head and neck masses. METHODS: In a prospective, randomized, single-blinded study, 209 patients served as their own controls and underwent 236 FNAs using ThinPrep and conventional (smear) cytopreparatory techniques. RESULTS: ThinPrep produced less air-drying artifact and less mechanical distortion than the conventional method. The conventional technique was diagnostic in 63% of samples; the ThinPrep technique was diagnostic in 55% of samples. When all results were combined, pathologists subjectively preferred the conventional technique but accepted use of ThinPrep as the only cytopreparatory technique for most head and neck masses. CONCLUSIONS: For adequately experienced cytopathologists, ThinPrep is acceptable for FNA of salivary masses, neck cysts, metastatic lymph nodes, and thyroid lesions. Conventional smear technique should be used for FNA of nonmetastatic lymphoid lesions. Use of ThinPrep can complement use of the conventional (smear) cytopreparatory technique when aspirate is nondiagnostic or bloody, when the patient has a blood-borne infectious disease, when the clinician is inexperienced, or when aspirate has entered the syringe.