The case for allele‐specific recognition by the TCR

There is a sharp difference in how one views TCR structure–function–behaviour dependent on whether its recognition of major histocompatibility complex‐encoded restriction elements (R) is germline selected or somatically generated. The generally accepted or Standard model is built on the assumption that recognition of R is by the V regions of the αβ TCR, which is not driven by allele specificity, whereas the competing model posits that recognition of R is allele‐specific. The establishing of allele‐specific recognition of R by the TCR would rule out the Standard model and clear the road to a consideration of a competing construct, the Tritope model. Here, the case for allele‐specific recognition (germline selected) is detailed making it obvious that the Standard model is untenable.     

梗阻性脑积水侧脑室及室周脑组织生物力学响应的有限元分析

目的运用有限元方法对梗阻性脑积水进行计算机模拟,研究分析侧脑室及室周脑组织的生物力学响应及其所产生的病理生理影响。方法依据正常国人颅脑MRI轴位T2加权图像获取解剖信息,在有限元软件ANSYS中生成包含侧脑室前、后角和体部的半侧脑层面的二维有限元模型。模拟脑组织为固、液两相物质组成的线性多孔弹性材料,设定生物力学特性参数及边界条件和初始条件,施加载荷,运用有限元软件ABAQUS进行计算求解,以云图形式输出结果。结果有限元模型动态模拟了梗阻性脑积水侧脑室各部的扩张过程,直观显示出各个时间步室周脑组织内的应力类型及分布、各部的应变和位移。结论膨胀性应力集中引起角部脑水肿;梗阻性脑积水早期侧脑室角部形态变化最明显;体部附近脑组织结构容易受压移位。这些生物力学响应是室内压增高的结果,也与侧脑室的解剖形态密切相关。     

Adipose tissues differentiated by adipose-derived stem cells harvested from transgenic mice

Objective: To induce adipocyte differentiation in vitro by adipose-derived stromal cells (ASCs) harvested from transgenic mice with green fluorescent protein (GFP) and assess the possibility of constructing adipose tissues via attachment of ASCs to typeⅡcollagen scaffolds. Methods: Inguinal fat pads from GFP transgenic mice were digested by enzymes for isolation of ASCs (primary culture). After expansion to three passages of ASCs, the cells were incubated in an adipogenic medium for two weeks, and the adipocyte differentiation by ASCs in vitro was assessed by morphological observation and Oil Red O staining. Then they were attached to collagen scaffolds and co-cultured for 12 hours, followed by hypodermic implantation to the dorsal skin of nude mice for 2 months. The newly-formed tissues were detected by HE staining. Results: The cultured primary stem cells were fibroblast-like and showed active proliferation. After being incubated in an adipocyte differentiation medium, the lipid droplets in the cytoplasm accumulated gradually and finally developed into mature adipocytes, which showed positive in Oil Red O staining. A 0. 5-cm3 new tissue clot was found under the dorsal skin of the nude mice and it was confirmed as mature adipose tissues by fluorescent observation and HE staining. Conclusions: ASCs can successfully differentiate adipose tissues into mature adipocytes, which exhibit an adipocyte-like morphology and express as intracytoplasmic lipid droplets. It is an efficient model of adipose tissues engineered with ASCs and type I collagen scaffolds.     

外伤性脾破裂切脾后及脾组织移植术后免疫功能观察分析

1952～1987年收治158例腹部闭合性损伤单纯脾破裂患者,其中全脾切除135例;脾切除并自体脾组织移植21例,脾破裂缝合修补2例。治愈率为98.1%,死亡率为1.9%。脾移植组及缝合修补组无1例死亡。92例获得免疫功能检验随访观察半年至35年,发现成人切脾后细胞免疫及体液免疫功能无明显影响,也未见脾切除后严重感染发生。认为成人除脾破裂表浅和局限易于修复或部分切除者外,均应行脾切除术,且无需行自体脾组织移植。小儿在脾切除后应行自体脾移植。     

人骨形态发生蛋白-2基因转染脂肪源性间充质干细胞的成骨研究

目的 探讨人骨形态发生蛋白-2（hBMP-2）基因修饰的人脂肪源性间充质干细胞（ADSCs）的成骨能力及基因转染对ADSCs成骨分化的生物学调控。方法 流式细胞技术鉴定从人脂肪组织中提取的细胞为间充质来源的干细胞。将ADSCs转染hBMP＋2基因，免疫沉淀＋Western blotting法和酶联免疫吸附试验（ELISA）检测hBMP-2表达，确定hBMP-2表达量及表达稳定性，碱性磷酸酶（ALP）染色、ALP定量测定、钙结节染色及RT—PCR分析hBMP-2基因转染对ADSCs向成骨细胞转化的调控，并将转基因细胞注入裸鼠股部肌内，通过X线及组织学检查观察体内成骨情况。结果 流式细胞术证实从脂肪中提取的细胞为间充质来源的干细胞。转基因后免疫沉淀＋Western blotting法和ELISA法显示转染hBMP-2的ADSCs具有较高且稳定的hBMP-2的表达，转染21d后表达量无明显降低。ALP染色、ALP定量测定、钙结节染色及RT—PCR发现转基因ADSCs向成骨细胞方向发生分化。裸鼠肌内注射转基因细胞后2周即显示有异位骨形成，4周明显增多，对照组无骨组织形成。结论 转染hBMP-2基因的ADSCs在持续稳定高表达目的蛋白的同时，自身向成骨细胞发生分化，并在裸鼠体内形成异位骨。因此，ADSCs有望作为新的基因工程种子细胞。     

Impact response of periodontal tissues

A new impact response method using a fracture of a pencil-lead to produce an excitation pulse is proposed. Impact excitations (rectangular pulse, triangular pulse and half-sine pulse) are strictly given in physical and mathematical definitions and complete solutions to the impact excitations are provided for Noyes' model of the human tooth. When a relatively long triangular pulse is applied to Noyes' model, which can express the physical characteristic of periodontal tissues, a sinusoidal damped vibration of a single degree-of-freedom model is approximately obtained. The acceleration response is characterised by the physical parameters (T, δ and A_o) and mechanical elements (m₁, c₁ and k) of which a single degree-of-freedom model is composed. By means of this method, the values of the parameters and elements in the cases of healthy maxillary, healthy mandibular and pathological mandibular incisors are obtained. The single degree-of-freedom model can express the high-frequency spectra of Noyes' model. The pathological tooth is characterised by a longer damped time constant and a larger acceleration maximum. This impact response method can effectively be applied to clinical diagnosis in view of the physical parameters and mechanical elements which have been derived.     

肉鸡对不同形态锰源的生物利用率研究

目的 :　研究肉仔鸡对不同形态锰源的相对生物学利用率。方法 :　将 62 4只 1日龄肉公鸡随机分为 1 3组 ,分别饲不添加锰的基础饲粮 (对照组 )或以不同锰化合物添加 60、1 2 0、1 80 mg/ kg锰的试验饲粮 2 1 d。结果 :　肉鸡生长性能各指标和腿病发生率以及肉鸡的跖骨灰锰含量、心肌细胞线粒体中 Mn SOD活性均未受到添加锰源以及锰源与锰水平互作的显著影响 ,但受到添加锰水平的显著影响。肉鸡心肌含锰量和 Mn SOD m RNA水平均未受到添加锰源与锰水平互作的显著影响 ,但受到添加锰源及添加锰水平的显著影响。其中中等和强络合强度有机锰源的生物学利用率明显高于无机硫酸锰和弱络合强度有机锰源。结论 :　中等和强络合强度的复合氨基酸锰对肉仔鸡的生物学利用率明显优于无机硫酸锰和弱络合强度的蛋氨酸锰     

红花注射液对家兔脑缺血再灌注损伤时氧自由基变化的影响

目的:探讨红花注射液对脑缺血-再灌注损伤(CIRI)的防治效应。方法:制作健康日本大耳白兔脑缺血-再灌注损伤模型,随机平均分为红花组(n=10)、缺血-再灌注组(n=10)和假手术对照组(n=10),应用黄嘌呤氧化酶法测定血浆SOD活性,用放免法测定血浆MDA浓度,并行脑组织电镜观察。结果:脑缺血再灌注期间,血浆SOD活性明显低于假手术对照组(P<0.05);血浆MDA浓度显著高于假手术对照组,尤以再灌注120min变化更显著(P<0.01);脑组织超微结构发生异常改变。使用红花注射液后,上述指标的异常变化均明显减轻,其差异有显著性。结论:氧自由基是CIRI的重要发病学因素之一,而红花注射液可能通过清除氧自由基减轻CIRI。