一种新型人TNFα对人肝癌裸鼠移植瘤的抗瘤作用

用人肝癌Ｂｅｌ７４０２瘤株建立了人肝癌裸鼠移植瘤模型，探讨新型重组人ＴＮＦａ对这种移植瘤的抗瘤作用，结果表明，ｒｈＴＦａＤ１１ａ和原型重组人ＴＮＦａ的抑瘤率在３０％左右时，后者后用的活性产闰数是前者的２倍；两者用量相同时，前者的抑产经比后者提高２３个百分     

HCMV感染动物胃肠组织损伤实验研究

目的 探讨HCMV感染是否引起大鼠和家兔胃肠组织损伤。方法 将人巨细胞病毒(Human Cyto—megalovirus，HCMV)AD168毒株静脉接种大鼠和新西兰兔，大鼠90d、兔30d后，检查动物胃、肠组织的病理变化，用免疫组化方法和原位杂交方法检查组织中的病毒抗原和DNA片段。结果 接种病毒之部分动物出现食量减少、粘液性大便，胃粘膜组织可见淋巴细胞浸润，肠粘膜变性坏死，甚至有穿孔灶；在粘膜细胞中查到病毒抗原或DNA片段。结论 HCMV感染可以侵犯动物胃肠组织并引起该组织病理损伤。     

Morphological analysis of renal cell culture models of calcium phosphate stone formation

Cell culture models of calcium phosphate renal stone formation were established using the MDCK cell line. Renal microliths were detected within pseudocysts in three-dimensional soft agar cultures, and were also observed in the basal region of cells lining the cell sheet, and immediately beneath domes or blisters in monolayers and collagen gel cultures. Light and scanning electron microscopy indicated that these microliths had a similar lamellated and spherical appearance to those in humans. These microliths were first detected microscopically after 21 days of culture, and were found to be composed of calcium phosphate by X-ray and microinfrared spectroscopic analyses. These culture models may provide a powerful new tool to study the pathogenesis of renal stone diseases and/or calcium phosphate stone formation in humans and animals.     

热休克反应对大鼠油酸肺保护作用的机制研究

未研究发现，经热休克处理的大鼠注油酸后，肺组织损伤明显减轻，Ｗｅｓｔｅｒｎ印迹分析显示热休克使大鼠肺组织中ＨＳＰ７０含量明显增多；Ｎｏｒｔｈｅｒｎ印迹分析证实此乃由于ＨＳＰ７０ｍＲＮＡ转录增加所致。说明热休克处理使肺组织ＨＳＰ７０基因表达增强；提示热休克反应对大鼠油酸肺的保护作用与肺组织细胞中ＨＳＰ７０基因表达增强及与ＨＳＰ７０增多有关。     

A model for estimating the potential costs and savings of osteoporosis prevention strategies

A model was developed which estimates the costs of osteoporosis risk evaluation and treatment, and the resulting savings in terms of reduced fracture frequency, for the adult female population of the United States. In the absence of treatment, the model predicts 1.44 million fractures will occur annually from non-violent causes. Treatment of all women beginning at age 50 with an agent that slows bone loss by 50% would reduce the number of these fractures by 0.59 million. Selective treatment of the 47% of women at the greatest fracture risk would reduce the number of fractures by 0.45 million, but would only cost 47% as much as treating all women. Additional data are required before the model can be used to evaluate specific treatment regimens. However, it appears that selective treatment of those at highest risk would yield the greatest benefit to cost ratio, if only benefits related to reduced fracture frequency are considered.     

When should bone density measurements be repeated?

We calculated how long to wait before repeating bone mineral density (BMD) measurements to reassess fracture risk. Correlation results from serial measurements of 495 postmenopausal Japanese-American women were used to estimate 95% confidence intervals (CI) for future BMD. After 7 years of follow-up, BMD correlations with the initial measurement ranged between 0.81 and 0.94, depending on age group and measurement site. In this analysis, the period between measurements was defined as the time required for the lower 95% CI to fall below the BMD value corresponding to doubling of fracture risk. Progressive bone loss causes fracture risk to double after 10 years, on average. However, the 95% CIs indicate that a second BMD measurement will detect risk doubling after only 2 or 3 years for some women. For untreated, early postmenopausal women, the period between measurements was approximately 2–5 years for the radius and 4–6 years for the calcaneus, depending on the initial BMD level. The period was approximately 1 year longer for women age 60 and older. Treatments that halve the bone loss rate would increase the period by 1–3 years. In the absence of a second measurement of BMD, the CI will continue to expand with time, corresponding to a wider range in risk between individuals, and a greater proportion of women will be at increased fracture risk. Obtaining a second BMD measurement pinpoints the patient's status within the precision of the measurement. We conclude that repeated BMD measurements will provide a more accurate estimate of fracture risk than a single, baseline measurement.     

Short utterance recognition using a network with minimum training

A feedforward network is used to recognize short, digitized, isolated utterances. A high, multispeaker recognition rate is achieved with a small vocabulary with a single training utterance. This approach makes use of the pattern recognition property of the network architecture to classify different temporal patterns in the multidimensional feature space. The network recognizes the utterances without the need of segmentation, phoneme identification, or time alignment. We train the network with four words spoken by one single speaker. The network is then able to recognize 20 tokens spoken by 5 other speakers. We repeat the above training and testing procedure using a different speaker's utterances for training each time. The overall accuracy is 97.5%. We compare this approach to the traditional dynamic programming (DP) approach, and find that DP with slope constraints of 0 and 1 achieve 98.5% and 85% accuracies respectively. Finally we validate out statistics by training and testing the network of a four-word subset of the Texas Instruments (Tl) isolated word database. The accuracy with this vocabulary exceeds 96%. By doubling the size of the training set, the accuracy is raised to 98%. Using a suitable threshold, we are able to raise the accuracy of one network from 87% to 98.5%. Thresholding applied to all networks would then raise the overall accuracy to well over 99%.

This technique is especially promising because of the low overhead and computational requirements, which make it suitable for a low cost, portable, command recognition type of application.     

丹参及血管内皮生长因子对动物肢体缺血模型侧支循环建立的作用

目的 :建立兔左后肢无主干及分支动脉供血的缺血模型 ,并观察丹参及血管内皮生长因子 ( VEGF)对兔后肢缺血模型侧支循环建立的作用。方法 :通过手术方法在兔后肢大腿段建立一个无主干及分支动脉供血的严重缺血模型。动物随机分为 5组 :未治疗组、丹参组、VEGF组、丹参加VEGF组及生理盐水对照治疗组。在解剖及生理水平上观察各组动物缺血肢体缺血及侧支循环建立情况。结果 :术后第 1天未治疗组动物左 /右小腿血压比为 0 ;动脉造影显示左侧只有髂外动脉中段以上显影、以下主干及分支均未显影。对侧后肢主干及分支动脉显影良好 ,即左侧毛细血管密度( 4 9.8± 1 7.6)个 /mm2 ,右侧为 ( 385 .7± 36.7)个 /mm2 ,P<0 .0 0 1 ;毛细血管数 /肌束数比值 :左侧( 0 .2 1± 0 .0 7) ,右侧 ( 0 .98± 0 .0 5 ) ,P<0 .0 0 1。治疗结束时 ,丹参加 VEGF组动物小腿血压比最高( 0 .74± 0 .1 7) ,它显著高于对照组、丹参组和 VEGF组 ;毛细血管密度与毛细血管数 /肌束数比值亦以丹参加 VEGF组为最高 ;动脉造影显示 ,丹参加 VEGF组中缺血组织处具有治疗意义的粗大的侧支循环形成。结论 :丹参与 VEGF联合应用具有强大的促进缺血模型侧支循环建立的作用     

反应停抗Lewis肺癌小鼠肿瘤血管生成的作用

目的 :研究具有抗血管生成作用的药物反应停对 Lewis肺癌小鼠皮下移植瘤和肺转移瘤的作用 ,并探讨其与肿瘤细胞凋亡的关系。方法 :2 4只皮下接种 Lewis肺癌肿瘤细胞 ( 1×1 0 6cell/mouse)的 C57BL/6小鼠随机分为两组 ,治疗组每日反应停 77.5 mg· kg-1灌胃 ,对照组每日生理盐水灌胃。第 2 1天处死动物 ,秤取瘤重、肺重 ,计数肺转移结节数 ,免疫组化染色后计数肿瘤组织微血管密度 ,流氏细胞仪测定分析肿瘤细胞凋亡率及细胞周期。结果 :反应停治疗组皮下移植瘤重量与对照组间差异无显著性 ( P>0 .0 5 ) ,但是肿瘤平均体积有下降趋势 ;反应停治疗组肺重、肺转移结节数目、肿瘤微血管密度低于对照组 ( P<0 .0 5 )。反应停治疗组肿瘤细胞凋亡率及 G1、S、G2 期肿瘤细胞百分数与对照组比较差异无显著性 ( P>0 .0 5 )。结论 :反应停有明显地抑制肿瘤细胞转移的作用 ,移植瘤体积有缩小的趋势 ,但不影响细胞的增殖周期