富铬酵母抗动脉粥样硬化的研究

本文观察了富铬酵母对早期动脉粥样硬化大鼠的预防及治疗作用。病理结果表明：在大鼠高脂饲料中接重量比加入０．１％的甲基硫氧嘧啶，在透射电镜下，大鼠主动脉内皮细胞可见大少；模型鼠改食普通饲料４０天，内皮下仍可见不典型泡沫细胞，内有空泡，而改食基础饲料并给富铬酵母治疗（０．２５ｇ／ＫｇＢｗ／ｄ），内皮下可见泡沫细胞，但空泡消失。在扫描电镜下，模型鼠主动脉内皮细胞肿胀、萎缩、排列紊乱，出现斑块状病变；给予富     

牙体修复材料体外充填密合度的扫描电镜研究

用扫描电镜直接观察及硅橡胶一环氧树脂扫描电镜复型技术观察银汞合金、ＥＢ复合树脂、玻璃离子粘固粉体外充填与釉质、牙骨／本质壁的边缘密合度。结果表明，与牙体组织呈化学性结合的玻璃离子粘固粉与釉质、牙骨／本质壁的密合度好，两壁之间无差别；ＥＢ复合树脂与釉质壁的边缘密合度与玻璃离子粘固粉相似，其缝隙明显小于牙骨／本质壁；银汞合金与釉质壁、牙骨／本质壁的边缘密合度差，且两壁之间无明显差别。     

Pseudoangiosarcomatous carcinoma: a clinicopathological study of seven cases

Seven cases of carcinoma mimicking angiosarcoma occurring in skin (3 cases), breast (3) and lung (1) are described. The cutaneous, pulmonary and one of the breast carcinomas were poorly differentiated and squamous in type; the other two breast tumours were poorly differentiated ductal carcinomas with focal squamous differentiation. Histologically, the pseudoangiosarcomatous pattern was due to complex anastomosing channels and spaces lined by neoplastic cells. The spaces contained hyaluronic acid. The neoplastic cells exhibited cytokeratin positivity but yielded negative results with the endothelial cell markers, factor VIII-related antigen and CD 34 (QB-END/10). Two breast tumours showed binding of UEA-1. Ultrastructurally, unequivocal epithelial differentiation was demonstrated in six of the cases. Pathogenetically, these tumours appeared to be variants of acantholytic squamous cell carcinoma. Recognition of this unusual form of carcinoma is important, as an incorrect diagnosis of angiosarcoma may lead to inappropriate treatment and prognostication.     

NMR Microscopy of Single Neurons Using Spin Echo and Line Narrowed 2DFT Imaging

NMR microimages of single neural cells were acquired at 500 MHz using a conventional spin echo pulse sequence and a line-narrowing sequence that eliminates susceptibility effects. The data show that any contribution to the measured T₂ relaxation rate arising from diffusion in local field inhomogeneities using spin echo sequences at high fields and high spatial resolution is relatively small. We conclude that the measured T₂ difference between the nucleus and cytoplasm in these cells represents primarily a true T₂ relaxation effect arising from the interactions of water with macromolecules in the two compartments and does not result from microsusceptibility differences. These observations have implications regarding water compartmentation in single cells and the interpretation of the MR characteristics of tissues in vivo.     

肠易激综合征患者结肠粘膜扫描电镜观察

应用扫描电镜观察１０例肠易激综合征（ＩＢＳ）患者降结肠粘膜的超微结构并和２例正常者进行比较性研究，结果发现ＩＢＳ组结肠粘膜上皮细胞表面微绒毛有局灶性破坏，破坏区微绒毛排列不整齐，数量稀少或缺如，结肠腺数量明显增多，腺窝开口大。腺窝处见有大量粘液分泌物和数量显著增多的杯状细胞。作者认为，ＩＢＳ并非是消化迫功能性疾病，而是有结肠粘膜超微结构改变的器质性疾病     

Experimental model of chronic tonsillar herniation associated with early stage syringomyelia

This report describes an experimental model of chronic tonsillar herniation and its effects on the spinal cord. In ten rats, a small piece of chemically induced mammary cancer was transplanted to the supraoccipital bone. In all cases, the transplanted cancers grew into the posterior fossa, destroying the supraoccipital bone and compressing the cerebellum extradurally. In six of the ten rats, tonsillar herniation was observed at 8–14 weeks after transplantation. Transdural infiltration of the tumor cells was not apparent in any animal. In those rats with tonsillar herniation (n=6), the spinal cord from the C5 to the T8 segments showed enlargement of the central canal without exception. Histological examination revealed the following changes: stretching and thinning of the ependymal cells; swelling of the astrocytic processes; and extracellular edema, predominantly in the dorsal gray matter, but also in the ventral inner portion of the dorsal column. In the control group (n=4) and those rats without tonsillar herniation (n=4), such histological changes of the spinal cord were not observed. Although the lesions can not be regarded as representing mature syringomyelia, they most likely constitute an earlier evolutionary stage.     

高功率微波辐照后大鼠肝组织的形态学改变

目的 探讨高功率微波(high power microwave，HPM)辐照后对大鼠肝组织形态结构的影响。方法雄性SD大鼠36只，随机分为两组，实验组(24只)和正常对照组(12只)，在微波辐照后6、24和48h及7d活杀大鼠，取肝脏组织；30mg／L戊二醛固定，进行常规扫描电镜标本制备；甲醛固定制备光镜标本。结果对照组肝细胞形态正常，肝板排列整齐。辐照后6h，肝细胞轻度肿胀。辐照后24h，肝细胞肿胀，肝板排列紊乱，肝窦狭窄。辐照后48h，肝细胞变性更明显，肝板排列严重紊乱，肝细胞空泡化明显，肝窦内广泛淤血。辐照后7d，肝细胞仍然肿胀，空泡化现象主要在中央静脉周围，肝窦内淤血有所减轻。结论高功率微波辐照对肝组织的损伤主要是发生肝细胞肿胀和肝窦淤血；这可能与辐照的致热效应，以及电场、电离作用等有关。     

角膜移植术后角膜在共焦显微镜下的形态学改变

目的：研究角膜移植术后角膜组织在共焦显微镜(Confocal microscopy)下的形态学改变。方法：应用Conoscan2．0共焦显微镜对板层角膜移植术后3～7d患者12例(12只眼)，术后1a患者8例(8只眼)，穿透性角膜移植术后3～7d患者10例(10只眼)，术后1a患者11例(11只眼)进行扫描检查，记录各层角膜图像。结果：板层角膜移植术后3～7d，植片中基质细胞较小，可见裂隙状暗纹和细小神经，层间为大面积高反光区，有点状颗粒沉积，植床水肿，细胞成像不清。移植术后1a，植片中未见神经，层间反光明显减弱，但仍有点状高反光颗粒沉积，植床中出现粗大裂隙状暗纹，内皮细胞密度正常。穿透角膜移植术后3～7d，植片中基质细胞“激活”，可见神经和后基质层的粗大暗纹，内皮细胞密度正常，细胞间可镶嵌有高反光点。术后1a，植片中基质细胞仍较小，未见神经，后基质层仍有裂隙状暗纹，内皮细胞体积增大，密度减少，高反光点消失。结论：Confoscan 2．0共焦显微镜可活体检查角膜移植术后角膜组织结构和细胞的病理改变，这对评估手术效果和临床观察以及跟踪随访具有重大意义。     

Ginkgo biloba Extract (EGb 761) Pretreatment Limits Free Radical Oxidative Stress in Patients Undergoing Coronary Bypass Surgery

A growing body of evidence supports the trigger role of free radicals in the delayed functional and metabolic myocardial recovery following cardiopulmonary bypass (CPB) in humans, thus opening the field to specific therapies. This clinical study was designed to evaluate, in 15 patients undergoing aortic valve replacement, whether the extent of CPB- and reperfusion-induced lipid peroxidation, ascorbate depletion, tissue necrosis, and cardiac dysfunction is reduced by orally administered EGb 761, a Ginkgo biloba extract withpotent in vitro antiradical properties. Patients received either EGb 761 (Tanakan, 320 mg/day, n = 8) or a matching placebo (n = 7) for 5 days before surgical intervention. Plasma samples were obtained from the peripheral circulation and the coronary sinus at crucial stages of the operation (i.e., before incision, during ischemia, and within the first 30 minutes post-unclamping), and up to 8 days postoperatively. Upon aortic unclamping, EGb 761 inhibited the transcardiac release of thiobarbituric acid species (p ` 0.05), as assessed by high-performance liquid chromatography, and attenuated the early (5–10 minute) decrease in dimethylsulfoxide/ascorbyl free radical levels, an electron spin resonance index of the plasma ascorbate pool (p ` 0.05). EGb 761 also significantly reduced the more delayed leakage of myoglobin (p = 0.007) and had an almost significant effect on ventricular myosin leakage (p = 0.053, 6 days postoperatively). The clinical outcome of recovery of treated patients was improved, but not significantly, compared with untreated patients. Our results demonstrate the usefulness of adjuvant EGb 761 therapy in limiting oxidative stress in cardiovascular surgery and suggest the possible role of highly bioavailable terpene constituents of the drug.     

The Cutaneous Microcirculation: Ultrastructure and Microanatomical Organization

The cutaneous microcirculation is organized as two horizontal plexuses. One is situated 1–1.5 mm below the skin surface, and the other is at the dermal-subcutaneous junction. Ascending arterioles and descending venules are paired as they connect the two plexuses. From the upper layer, arterial capillaries arise to form the dermal papillary loops that represent the nutritive component of the skin circulation. There are sphincter-like smooth muscle cells at the point where the ascending arterioles divide to form the arteriolar component of the upper horizontal plexus. At the dermal subcutaneous junction, there are collecting veins with 2-cusped valves that are oriented to prevent the retrograde flow of blood. Laser Doppler flowmetry (LDF) has demonstrated vasomotion of red cell flux localized to the sites of ascending arterioles. The simultaneous recording by LDF of red cell flux and the concentration of moving red blood cells from individual sites allows one to construct by computer topographic maps of these two valves. The two maps, based on initial studies using correlative skin biopsy specimens, can define 1-mm³ volumes of skin that are predominantly arteriolar in composition, predominantly venular in composition, or essentially devoid of all microvascular elements. The electron and light microscopic features that define the microvascular segments, when coupled with the ability of LDF to define the predominant microvascular segments under the probe, will allow one to study both the mechanisms of normal physiological states and the pathogenetic mechanisms underlying pathological skin disorders in which the microvasculature plays a predominant role.