Rigid contact lens decentration: a risk factor for corneal warpage

Clinically significant contact lens induced corneal warpage is seen in a small proportion of soft and rigid contact lens wearers. Previous studies using the keratometer have found no correlation between the fit of the lens and the induced topographic changes. In this study, using computer-assisted topographic analysis, seven eyes (four patients) with rigid contact lens-induced corneal warpage were noted to have topographic abnormalities that correlated with the decentered resting position of the contact lens on the cornea. The warpage topography for each of these corneas was characterized by a relative flattening of the cornea underlying the resting position of the contact lens. Lenses that rode high, for example, produced flattening superiorly and resulted in a relatively steeper contour inferiorly that simulated the topography of early keratoconus patients who had not worn contact lenses. After discontinuing contact lenses the corneal topography returned to a normal pattern in five eyes. Two eyes retained asymmetry that is not characteristic of normal corneas. Up to 6 months was required for the corneas to return to a stable topography after contact lens wear was discontinued.     

日本血吸虫尾蚴至童虫期超微结构变化与生理适应的关系

本文应用透射电镜观察比较日本血吸虫尾蚴和皮肤型童虫的体壁、腺体和消化道的超微结构。结果表明,从尾蚴至皮肤型童虫转变过程,其体壁和钻腺的超微结构发生明显改变,但头腺及消化道则未见明显变化。这些变化与其相应的微环境密切相关。     

Increased expression of MHC class II antigens in rejecting canine lung allografts

Expression of major histocompatibility complex class II antigens was investigated in the normal lungs and in lung allografts of mongrel dogs after single-lung transplantation. Cryostat sections were stained with an indirect immunoperoxidase technique that used B1F6 and 7.5.10.1 as anti-MHC class II monoclonal antibodies. In the normal lungs and native lungs of the recipient dogs after single-lung transplantation, only some cells of lymphoid tissue and macrophages/dendritic cells were MHC class II-positive. During acute rejection, increased infiltration with MHC class II-positive cells in perivascular, peribronchial, and interstitial areas and intraalveolar spaces was found in lung allografts. In addition, expression of MHC class II antigens was induced on the bronchial epithelium and vascular endothelium. Induced expression of MHC class II antigens on the bronchial epithelium and vascular endothelium in rejecting lung allografts was found as early as two days after single-lung transplantation. The intensity of MHC class II antigen expression on bronchial epithelium and vascular endothelium in graft lungs increased with the progression of rejection response and directly correlated with the bronchoalveolar lavage fluid (BALF) levels of biochemical markers, as tumor necrosis factor alpha, gamma-interferon (IFN-gamma), interleukin 2 (IL-2) and soluble interleukin 2 receptor (SIL-2R). Abnormal expression of MHC class II antigens on bronchial epithelium and vascular endothelium and abnormal elevation of BALF levels of the cytokines in lung allografts could be prevented by cyclosporine (CsA) treatment. Our results suggested that MHC class II antigen expression could be induced on the bronchial epithelium and vascular endothelium of canine lung allografts during acute rejection. This abnormal expression of MHC class II antigens on bronchial epithelium and vascular endothelium of graft lungs may serve as a specific index for diagnosis of lung allograft rejection when infection as an inducing factor can be excluded. Furthermore, bronchial epithelium and vascular endothelium of lung allografts have become MHC class II-positive, and are likely to be the targets for low-grade rejection, resulting in the development of bronchiolitis obliterans and occlusive vascular disease in lung allografts.     

中国汉族群体D4S111位点的遗传多态性研究

目的：研究中国汉族群体中α艾杜糖苷酶基因Ｄ４Ｓ１１１位点的遗传多态性。方法：采用扩增片段长度多态性（ＡｍｐＦＬＰ）分析技术，检测了广州地区汉族无血缘关系健康个体９７名。结果：Ｄ４Ｓ１１１位点，在９７名无关个体中发现５个等位基因和９种基因型，等位基因片段长度为８３０～５１０ｂｐ，基因频率为０００５２～０３６０８，ＰＩＣ为０５９６６，杂合性为０７８。结论：中国汉族群体中Ｄ４Ｓ１１１位点具有高度多态性，并与其它种族间存在差异性。     

真皮下血管网岛状皮瓣抗菌力的实验研究

为研究真皮下血管网薄皮瓣用于感染创面的可行性，在家猪臀部两侧分别形成以旋髂深血管主干分支为蒂的传统岛状皮瓣和远侧５０％修薄的真皮下血管网岛状皮瓣。用细菌计数、吖啶橙荧光染色测定白细胞吞噬指数和白细胞内杀菌率，应用激光多普勒、墨汁灌注、透明标本等方法，对两种皮瓣的抗菌力作自身对照研究。结果表明，真皮下血管网岛状皮瓣的抗菌力明显降低，可能与皮瓣修薄后血供减少，白细胞功能相应降低有关。     

Effect of Yag-laser anterior capsulotomy on the biochemical content of aqueous humor

Elevation of prostaglandins and protein in the aqueous humor is an immediate response to Yag-laser anterior capsulotomy. There was a significant correlation between prostaglandins and thromboxane to the elevation of intraocular pressure. The elevation of protein concentration was proportional to the elevation of prostaglandin F1, but not to thromboxane. The biochemical changes in the aqueous humor were more severe as laser power was increased above 3 mj. While the role of prostaglandins in the elevation of intraocular pressure is uncertain, the present data recommend the selection of laser power below 3 mj to avoid pressure rise instead of inhibition of all prostaglandin synthesis by medication.     

口腔固定修复学临床前期实习中的问题与对策

本文总结了北京大学口腔医学院3届八年制口腔医学专业学生口腔固定修复学临床前期实习教学的经验,针对实习中出现的典型问题进行了分析,采取了相应的对策和方法,取得了良好的效果.     

聋幼儿情绪状态对认知发展的影响

为促进聋幼儿各方面的正常发展，使其早日回归主流社会，我们对聋幼儿进行了认知和情绪表现的研究。通过问卷调查、观察和实验研究得知，聋幼儿的认知发展和良好情绪的培养是分不开的，认知内容适中有利于聋幼儿良好情绪的培养，而良好积极的情绪又可促进聋幼儿认知的发展。对此，我们实验并总结了培养聋幼儿积极情绪和促进认知发展的方法。     

探讨快速维修现代放射影像设备的基本方法与步骤

介绍快速确定现代放射影像设备故障的所在部位与原因的方法与步骤,简述了11种快速维修的基本方法.