3种低温保存板层角膜移植材料的电镜观察

评价低温保存板层角膜移植材料的效果。方法将１５只人尸角膜分三组保存２年：４℃甘油脱水法,角膜液氮冷冻法,全眼球液氮冷冻法。并做透射电镜观察。结果第一组中,角膜胶原纤维排列紊乱,疏松,缺乏连续性,可见广纤维变性,纤维间可见极低电子密度灶。     

左室重量与左心功能不全相关性的研究

目的：研究可否用左室重量表达并判定左心功能不全的可能性。方法：将左心功能不全按NYHA标准分成4个级别,每级1组,并设正常对照组,用超声心动图测量同一个病人的左室射血分数（LVEF）和左室重量。用SAS统计软件做方差分析。结果：LVEF与左心功能不全高度负相关（R＝－0．77270）,左室重量与左心功能不全高度正相关（R＝0．73421）。LVEF、左室重量各级指标间差别显著（n＝153,F＝64．85,P＜0．01;n＝153,F＝53．39,P＜0．0001）。各级与对照组比统,LVEF指标从Ⅱ级开始方有显著差别（P＜0．05）;而左室重量指标从Ⅰ级开始就有显著差别（P＜0．05）。结论：LVEF与左室重量指标均与左心功能不全高度相关,但心功能Ⅰ级的病人,左室重量指标更为敏感。     

咬合板治疗颞下颌关节紊乱病的时机与疗效

目的：通过对颞下颌关节紊乱病（ＴＭＤ） 的临床表现及咬合板治疗的疗效进行分析,探讨ＴＭＤ 的最佳治疗时机。方法：对１５６ 例经咬合板治疗的ＴＭＤ患者就诊时间及治疗２ 个月后治疗效果做分类统计分析。结果：治疗２ 个月后疼痛、弹响及张口受限的总治愈率分别为８１．４％ 、４９．０％ 和８１．５％ 。其中于发病４ 周内就诊的患者治愈率分别为９３．２％ 、７７．３％ 和９３．２％ ,于４ 周后就诊的患者治愈率分别为７３．９％ 、４０．８ ％ 和３０．０ ％ ,两组差异显著（ 弹响及张口受限, Ｐ＜ ０．０１,疼痛Ｐ＜０．０５）。结论：ＴＭＤ在发病４ 周内进行咬合板治疗效果满意。     

聚合酶链反应检测细菌16S rRNA基因

根据细菌１６ＳｒＲＮＡ基因的高度保守性,设计合成所有细菌、革兰氏阳性细菌及革兰氏阴性细菌的共同引物,采用聚合酶链反应检测已知细菌１３株,三对引物分别扩增的阳性率为１００％,倍比稀释法能检出细菌的最低浓度为４ＣＦＵ·ｍｌ－１,同时检测临床样本４０份,阳性率为６７５％（２７／４０）,同期细菌培养阳性率为４５％（１８／４０）,二者比较差异有显著性（Ｐ＜０．０５）。结果提示聚合酶链反应检测细菌１６ＳｒＲＮＡ基因具有高度的特异性和敏感性。     

大鼠弥漫性脑损伤不同脑部位不同时相的脂质过氧化反应

利用Ｍａｒｍａｒｏｕ氏脑损伤动物模型,测定大鼠脑损伤后不同时间和部位的丙二醛（ＭＤＡ）含量。结果示：损伤后１ｈ,额叶、顶叶、脑干等处的ＭＤＡ水平分别比对照组高出３６７％,４１８％和３５１％（Ｐ＜０．０１）,并持续增高,伤后４ｈ达高峰后缓慢下降,伤后２４ｈ仍明显高于对照组。纹状体、颞叶等处伤后１ｈ的ＭＤＡ水平升高较上述部位稍低,而分别较对照组升高１６９％和１３３％（Ｐ＜０．０１）,伤后４ｈ虽仍持续升高,但不超过３５％。提示在大鼠弥漫性脑损伤后短期内即有自由基生成,几乎波及脑内各个部位,但程度不一。     

抗辐射菌DNA结合蛋白的氨基酸序列分析

目的　对抗辐射菌Ｄ．ｒａｄｉｏｕｄｕｒａｎｓ 的ＤＮＡ结合蛋白（ＤＢＰ） 进行Ｎ－ 末端氨基酸（ＡＡ） 序列分析,探讨其抗辐射分子学组成的特性。方法　采用地高辛（ＤＩＧ） 标记染色体ＤＮＡ 作为探针,ＳｏｕｔｈＷｅｓｔｅｒｎ 印迹法检测ＤＢＰ,在Ｎ－ 端ＡＡ 自动序列仪上分析ＡＡ序列。结果　野生型抗辐射菌存有８ 种ＤＢＰ的特性蛋白（分子量分别为１２２、９３、３３、２９、１６、１５、１４ 和１２ｋｄ）;ＡＡ 序列分析发现其中９３ｋｄ 和３３ｋｄ 可能为新的蛋白质;两种新ＤＢＰ 的表达水平随不同培养基和培养时间而变化。结论　抗辐射菌的ＤＢＰ,尤其是９３ｋｄ 和３３ｋｄ 的ＤＢＰ与其辐射耐受性可能有密切关系     

Antioxidant administration inhibits exercise-induced thymocyte apoptosis in rats

PURPOSE: The purpose of this study was to investigate the effect of antioxidant on exercise-induced apoptosis in rat thymocytes. METHODS: After exercise at 13.8 m x min(-1) for 60-90 min x d(-1) on a motor-driven drum exerciser for 2 consecutive days, rat thymocyte apoptosis was monitored by the feature of DNA fragmentation. To study the effect of antioxidant, rats were administered with butylated hydroxyanisole (BHA) for 7 d before exercise. RESULTS: Exercise could induce thymocyte DNA fragmentation as detected on electrophoretic gel and by cell death detection ELISA kit. Further studies indicated that pretreatment with antioxidant BHA to rats resulted in a blockage of exercise-induced DNA fragmentation. The concentrations of glutathione (GSH) were not significantly changed in rat thymocytes after exercise with or without BHA treatment. CONCLUSION: These results suggest that reactive oxygen species may play a role in thymocyte apoptosis induced by exercise. However, changes in GSH levels were not observed in this exercise model.     

Mechanism of adrenal insufficiency following trauma and severe hemorrhage: role of hepatic 11beta-hydroxysteroid dehydrogenase

BACKGROUND: Although adrenal insufficiency may not occur with moderate hypotension, it does occur with severe hemorrhage. Since hepatocellular function is depressed following severe hemorrhage, it remains unknown whether the liver plays any role in regulating adrenal function after trauma and hemorrhagic shock. HYPOTHESIS: Hepatic 11beta-hydroxysteroid dehydrogenase (11beta-HSD), a microsomal enzyme responsible for the degradation of bioactive corticosterone, plays a major role in the development of adrenal insufficiency following trauma and severe hemorrhage. DESIGN, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Male rats underwent laparotomy to induce trauma before hemorrhage. They were then bled to and maintained at a blood pressure of 40 mm Hg until 40% of the maximal bleed-out volume was returned in the form of Ringer lactate. The rats were then resuscitated with 4 times the volume of maximal bleed-out with Ringer lactate during a 60-minute period. Plasma levels of corticosterone and corticotropin were measured at various intervals. In additional groups, corticotropin-induced corticosterone release, adrenal contents of corticosterone and cyclic adenosine monophosphate (cAMP), hepatic 11beta-HSD activity, and plasma levels of corticosterone-binding globulin were determined at 1.5 hours after resuscitation. Moreover, a model of moderate hypotension (blood pressure, 80 mm Hg) was used to determine whether adrenal function is depressed under such conditions. RESULTS: At the time of maximal bleed-out, plasma corticosterone and corticotropin levels increased by 245% (P<.001) and 293% (P<.001), respectively. Despite corticotropin levels being similar to those of the animals undergoing sham operation after resuscitation, corticosterone levels in hemorrhaged animals remained elevated up to 4 hours after resuscitation (by 158%-207%; P<.001). In addition, corticotropin-induced corticosterone release decreased by 78% at 1.5 hours after resuscitation (P = .009). In contrast, moderate hypotension did not reduce corticotropin-induced corticosterone release. Adrenal corticosterone content and cAMP levels (i.e., the second messenger of corticotropin action) decreased by 55% (P<.001) and 25% (P = .03), respectively. Hepatic 11beta-HSD activity decreased significantly at 1.5 hours after resuscitation (P<.001). CONCLUSIONS: Sustained increase in plasma corticosterone levels following hemorrhage and resuscitation may be, in part, due to the decreased hepatic 11beta-HSD activity. The high level of corticosterone negatively regulates corticotropin release, further reducing adrenal responsiveness to corticotropin stimulation. Thus, the liver appears to play an important role in regulating adrenal function following trauma and severe hemorrhage.     

Intimate combination of low- and high-resolution image data: I. Real-space PET and (1)H(2)O MRI, PETAMRI.

Two different types of (co-registered) images of the same slice of tissue will generally have different spatial resolutions. The judicious pixel-by-pixel combination of their data can be accomplished to yield a single image exhibiting properties of both. Here, axial (18)FDG PET and (1)H(2)O MR images of the human brain are used as the low- and high-resolution members of the pair. A color scale is necessary in order to provide for separate intensity parameters from the two image types. However, not all color scales can accommodate this separability. The HSV color model allows one to choose a color scale in which the intensity of the low-resolution image type is coded as hue, while that of the high-resolution type is coded as value, a reasonably independent parameter. Furthermore, the high-resolution image must have high contrast and be quantitative in the same sense as the low-resolution image almost always is. Here, relaxographic MR images (naturally segmented quantitative (1)H(2)O spin-density components) are used. Their essentially complete contrast serves to effect an apparent editing function when encoded as the value of the color scale. Thus, the combination of (18)FDG PET images with gray-matter (GM) relaxographic (1)H(2)O images produces visually "GM-edited" (18)FDG PETAMR (positron emission tomography and magnetic resonance) images. These exhibit the high sensitivity to tracer amounts characteristic of PET along with the high spatial resolution of (1)H(2)O MRI. At the same time, however, they retain the complete quantitative measures of each of their basis images. Magn Reson Med 42:345-360, 1999. Published 1999 Wiley-Liss, Inc.