20世纪后半叶美国高等医学教育改革历程

美国现代高等医学教育模式的确立是以20世纪初Flexner报告发表为开端的。第二次世界大战前，现代高等医学教育体系已基本完善，并经历了二战的考验。二战后，随着社会和医学发展，美国高等医学教育一直在进行着改革。按照时间顺序在50年代、60年代以及70、80年代进行了改革。分析历次改革的背景、主要内容及改革的特点特别对指导20世纪80年代后医学教育改革的纲领性文件——GPEP报告进行详细阐述，包括GPEP报告的内容、作用以及与Flexner报告的对比分析。通过回顾与分析，对美国医学教育改革历程中的成功经验和不足之处进行梳理，为我国正在进行的高等医学教育改革提供借鉴与参考。     

制作角膜缘干细胞完全缺乏动物模型的新方法

目的提出一种新的角膜缘干细胞完全缺乏模型制作方法,为干细胞缺乏疾病的治疗性研究提供可靠的模型。方法利用9mm环钻划界,板层切除角膜组织,通过临床评分、印迹细胞学、组织病理及免疫组织化学验证模型的成功。结果板层切除术后30~45d,模型眼角膜混浊、上皮缺损、大量新生血管长入,印迹细胞学可见PAS( )的杯状细胞,组织病理学检查上皮符合结膜细胞表型,免疫荧光染色可见结膜杯状细胞特异性标志MUC5AC阳性表达。结论环钻划界加板层切除法为一种可靠、有效的角膜缘干细胞完全缺乏模型制作方法。     

影响重型肝炎预后的因素分析

目的研究重型肝炎的各种预后因素的重要性。方法选择2000年1月至2004年12月我院收治的重型肝炎患者358例,分为好转治愈组和恶化死亡组,将两组的临床资料进行单因素和多因素分析。结果两组之间在凝血酶原活动度、肝性脑病、总胆红素和天冬氨酸氨基转移酶/丙氨酸氨基转移酶等方面有显著性差异(P<0.05)。结论凝血酶原活动度、肝性脑病、总胆红素和天冬氨酸氨基转移酶/丙氨酸氨基转移酶比值等可以作为判断重型肝炎预后的指标,对指导临床有一定价值。     

Comparison of diagnostic usefulness of predictive models in preliminary differentiation of adnexal masses

The purpose of this study was to compare prognostic models evaluating the probability of an ovarian cancer occurrence based on a number of clinical and ultrasonographic data in women with adnexal masses. A total of 686 women with adnexal masses underwent the examinations between 1994 and 2002. The recorded parameters included: age, menopausal status, body mass index, the grayscale and Doppler ultrasonographic examination, and selected markers concentration levels. In order to find the best combination of features, which significantly influences the probability of malignancy, stepwise logistic regression analysis, as well as artificial neural network, was used. The diagnostic efficiency of received models was estimated and compared using receiver-operating characteristics (ROC) curve. The results indicate that 431 and 255 patients had a benign and malignant ovarian tumor, respectively. Application of stepwise logistic regression analysis revealed statistically significant importance of eight features. The sensitivity and specificity for the received model were 65.71% and 77.59%, respectively. Three-layer perceptron network shows 13 features as significant predictors of malignancy. The network gave a sensitivity of 85.7% and specificity of 93.1%. Comparison of area under ROC curve for received models was 0.9679 vs 0.9716. Prognostic values of the analyzed neural model are not optimal but seem to surpass logistic regression model in terms of the predictive possibilities.     

Therapeutic effect of antimicrobial drugs against experimental infections due toYersinia pestis in mice

Although there are effective antibacterial agents against plague, newer antibacterial agents have been developed which show more potent activity against other bacterial organisms, but have not been tested againstYersinia pestis. A strain ofYersinia pestis was selected (no. 22; National Institute of Infectious Diseases, Tokyo, Japan) that caused a systemic infection in mice.Y. pestis no. 22 was intraperitoneally inoculated into DDY-strain mice, and 13 oral or 6 injectable antibacterial drugs given to the infected mice at varying doses 1 and 24 hours after infection. Levofloxacin, sparfloxacin and ofloxacin were the most effective oral agents against the infection, and prulifloxacin and pazufloxacin were also effective but to a lesser extent. Also, gentamicin and arbekacin were the most potent injectable antibacterial agents againstY. pestis. These results suggest that there are several new drugs, both oral and injectable, which exert excellent in vivo antibacterial activity against a mouse infection model and may be useful for the clinical treatment of plague.     

混合Poisson分布及其应用：疾病的统计分布（五）

本文讨论了混合Ｐｏｉｓｓｏｎ分布的性质、应用条件、参数的估计及混合Ｐｏｉｓｓｏｎ分布阶数的确定，指出混合Ｐｏｉｓｓｏｎ分布可用于混合样本的判别归类，并用Ｂａｙｅｓ的思想导出其判别归类方法。模拟试验结果表明：当混合Ｐｏｉｓｓｏｎ分布中各部分的比例相差不大，而各部分的均值相差较大时，抽样效果和拟合效果越好，所得到的估计值越接近理论值；反之效果越差。     

实验性精索静脉曲张对大鼠睾丸生精细胞凋亡的影响

目的 :探讨大鼠精索静脉曲张对睾丸生精细胞凋亡的影响 ,阐明精索静脉曲张引起不育的病理机制。　方法 :选用雄性SD大鼠 32只 ,随机分为假手术组、4 5d模型组、6 0d模型组及 90d模型组。采用肾静脉缩窄法建立精索静脉曲张动物模型 ,流式细胞术分别检测各组大鼠睾丸凋亡细胞数及各级生精细胞数。　结果 :假手术组未出现明显的凋亡峰 ,各模型组均出现明显的凋亡峰 ,且随着造模时间的延长凋亡峰增高。　结论 :精索静脉曲张可引起睾丸生精细胞大量凋亡 ,各级生精细胞数减少 ,这可能是精索静脉曲张引起睾丸生精功能障碍从而导致不育的根本机制     

Preventing heart disease: is treating the high risk sufficient?

Monte Carlo simulation was used to assess the effects of several intervention strategies on coronary heart disease mortality rates in a Finnish and a North American cohort. Lowering total serum cholesterol by 4%, smoking by 15%, and diastolic blood pressure by 3% for the whole cohort would be expected to reduce the incidence of non-fatal myocardial infarction by at least 13% and coronary heart disease deaths by at least 18%. Lowering serum cholesterol by 34%, diastolic blood pressure to 90 mmHg, and reducing smoking by 20% in the subset of the population with all three risk factors in the highest quartile would result in a 6-8% reduction in non-fatal myocardial infarction and a 2-9% reduction in deaths from coronary heart disease in these cohorts. These data demonstrate that in populations with a relatively high incidence of heart disease, treating the entire population will produce larger effects than focusing only on high-risk populations.     

Segregation analysis of leprosy in families of northern Thailand

Sixty-three families with multiple instances of leprosy were identified through a major leprosy treatment center in northern Thailand. Complex segregation analyses for single major genes or polygenic inheritance were performed using the maximum-likelihood routine POINTER to determine the most likely etiologic model of genetic susceptibility. Liability differences between men and women were considered in these models. When individuals were considered to be affected because they had any form of leprosy, a generalized major gene model with nearly dominant parameters on the liability scale, but additive penetrances, was found to be the most likely. When only those individuals who had tuberculoid forms of leprosy were considered to be affected, a recessive model was found to be the most likely; however, the discrimination between various models was poor. Further analyses are necessary to delineate genetic mechanisms to explain these apparently divergent results. In particular, methods of testing two locus models should be considered.     

豚鼠耳蜗微血管内皮细胞体外通透性的研究

目的　研究豚鼠耳蜗微血管内皮细胞的体外通透性特征。方法　在成功建立豚鼠耳蜗微血管内皮细胞体外通透性模型的基础上 ,研究该体外模型跨细胞电阻及对12 5I 牛血清白蛋白的通透性。结果　①耳蜗微血管内皮细胞在培养增殖过程中其跨细胞电阻呈动态变化过程 ,以 5× 10 4/cm2 的细胞密度接种时 ,7d左右电阻到达峰值 ,其跨细胞电阻峰值大小为 (118 9± 18 5 )Ω/cm2 ;②体外模型中加入12 5I 牛血清白蛋白后 ,其通透性呈上升期抛物线型曲线 ,90min内几乎呈直线。结论　跨细胞电阻及对12 5I 牛血清白蛋白变化曲线能反映体外耳蜗微血管内皮细胞的通透性特征