Effect of distance and population size on patient trips in a prefecture of Japan: Application of a transportation distribution model to the demand for and supply of health services

The gravity model, a method for analyzing transportation distribution in transportation engineering, was used to explain patient trips between ten health service regions in a Japanese prefecture. The OD (Origin-Destination) tables were constructed with zoning by regions, distinguishing between out- and inpatients. The observed trips were determined from the data of a survey conducted in 1992 that reported the locations of patient residences and chosen medical facilities. The base values used in the model calculations were the population size of each region and the road distance between the centers of regions. Problems of intrazonal trip were avoided by setting a mean intrazonal movement distance. This model was calibrated by the linear regression method with simultaneous validation by the index of correlation coefficients. The model was found to accurately simulate the effect of distance on the choice of medical facilities and the differences between the characteristics of in- and out-patients. The population value in use showed the relation not only with demand but also the supply of clinical services. It was suggested that the model presented here was useful in the allocation of medical resources and would help explain the relationship between suppliers and consumers of medical services.     

Flow-mediated cell stress induction in adherent leukocytes is accompanied by modulation of morphology and phagocytic function

Leukocytes adherent to the surfaces of both vascular biomaterials and normal blood vessels experience blood flow induced shear stress. The goal of the reported studies was to investigate the effect of fluid flow on the morphology, phagocytic function and stress response induction in adherent immune cells. Shear approximating arterial, venous and intermediate levels were applied onto glass-adherent IC21 macrophages in a temperature-controlled parallel plate flow system. The results indicate that fluid flow induces a shear-dependent physiological stress response in adherent macrophages and that significant morphological changes accompany macrophage responses to shear stress. In addition, arterial flow conditions induce not only significant cell polarisation, but also enhanced phagocytic ingestion in glass-adherent IC21 macrophages. These findings suggest that blood flow induced shear stress may not only be consequent to adherent leukocyte activation, but may also be integral to the regulation of adherent leukocyte behaviour in vivo.     

Left-ventricular pressure gradients: a computer-model simulation

Both invasive left-ventricular pressure measurements and non-invasive colour M-mode echographic measurements have shown the existence of intraventricular pressure gradients (IVPGs) during early filling. The mechanisms responsible for these IVPG cannot be completely explained by the experiments. Therefore a one-dimensional numerical model is developed and validated. The model describes filling (both velocities and pressures) along a left ventricular (LV) base-apex axis. Blood-wall interaction in the left ventricle with moving boundaries is taken into account. The computational results for a canine heart indicate that the observed IVPGs during filling are the consequence of a complex interaction between, on the one hand, pressure waves travelling in the LV and, on the other hand, LV geometry, relaxation and compliance. The computational results indicate the pressure dependency of wavespeed (0.77-1.90 m-1 s) for different mean intraventricular pressures (0.88-5.00 mmHg) and IVPGs up to 2 mmHg, independent of the ratio of end systolic volume and equilibrium volume. Increasing relaxation rate not only decreases minimum basal pressure (2.8 instead of 3.6 mmHg) but also has a strong influence on the time delay between the minimum basal and apical pressures (14 ms instead of 49 ms). The results sustain the hypothesis that pressure-wave propagation determines IVPGs and that IVPGs are no proof of elastic recoil.     

肿瘤抗原脉冲致敏的树突状细胞疫苗抗肿瘤作用的实验研究

目的：进一步研究体外肿瘤抗原脉冲致敏的骨髓树突状细胞瘤苗主动免疫诱导小鼠体内抗肿瘤免疫应答,并观察其抵抗野生性肿瘤攻击的免疫保护作用及对荷瘤小鼠模型的免疫应答。方法：采用本室建立的骨髓树突状细胞分离与细胞因子体外扩增培养方法,并在体外经灭活ＮＳ１骨髓瘤细胞及其裂解产物脉冲刺激后直接作为疫苗,然后进行免疫预防与治疗的在体动物实验。结果：可从１只小鼠股骨中获得（３～５）×１０５个树突状细胞（ＤＣ）,其纯度为９５％以上,对混合Ｔ淋巴细胞具有强刺激活性。主动免疫同系健康ＢＡＬＢ／Ｃ小鼠的试验显示,ＤＣ疫苗能诱导抗原特异的细胞毒性Ｔ淋巴细胞（ＣＴＬ）活性,免疫１次的动物首次受到肿瘤攻击后诱发肿瘤形成率为０％,再次攻击的肿瘤形成率为２０％;而免疫３次的动物两次攻击的肿瘤形成率皆为０％。主动免疫治疗同种荷瘤动物的试验表明,ＤＣ疫苗也能抑制肿瘤生长,荷瘤动物存活率提高及生存期明显延长。结论：肿瘤抗原体外致敏的树突状细胞能诱导宿主体内的抗肿瘤免疫保护性反应,且对荷瘤模型动物具有明显的免疫治疗作用。     

骨髓树突状细胞融合瘤苗抗肿瘤免疫预防与治疗的实验研究

目的：进一步研究树突状细胞与肿瘤细胞的融合瘤苗细胞主动免疫诱导体内抗肿瘤免疫反应及对荷瘤小鼠的免疫治疗效果。方法：直接分离骨髓树突状细胞和体外生长因子诱导扩增培养相结合,获得大量高纯度的树突状细胞,再以５００ｇ／ＬＰＥＧ诱导其与ＮＳ１骨髓细胞融合,ＨＡＴ选择培养得到两者的融合细胞,体外进行混合淋巴细胞培养,并进行免疫预防与治疗的在体动物实验。结果：融合细胞也能诱导淋巴细胞的增殖反应,而ＮＳ１无此作用。体内免疫预防试验表明,融合细胞活瘤苗１次免疫后,诱导出较强的细胞毒性Ｔ淋巴细胞（ＣＴＬ）,并获得抵抗野生型ＮＳ１攻击的保护性反应,但对无关瘤株则无此抵抗力。融合细胞对荷瘤小鼠的免疫治疗试验显示,融合细胞静脉注射后,能够明显抑制肿瘤生长,延长其生存期。结论：树突状细胞与肿瘤细胞融合后的瘤苗体内免疫,能有效地诱导抗肿瘤免疫反应,可望成为肿瘤免疫预防和免疫治疗的新途径。     

载脂蛋白(a)亚型与脑梗塞的病因学联系

为探讨 Ｌｐ（ａ）、ａｐｏ（ａ）与脑梗塞病因学的关系,阐明ａｐｏ（ａ）基因表型对脑梗塞的调控作用,检测了 ９０ 例经 Ｃ Ｔ 确诊的脑梗塞患者血清 Ｌｐ（ａ）含量,并分离出 １３ 种 ａｐｏ（ａ）表型,与对照（以年龄、性别配比）比较。结果表明,高 Ｌｐ（ａ）者（≥３０ｍ ｇ／ｄｌ）患脑梗塞的危险性为正常者（＜ ３０ｍ ｇ／ｄｌ）的 ３５６ 倍（ Ｐ＜ ０．０１）,ａｐｏ（ａ）分子量与 Ｌｐ（ａ）水平呈高度负相关,ｒ＝ － ０．４８１,说明 ａｐｏ（ａ）大小决定了约 ４８％ 的 Ｌｐ（ａ）水平。ａｐｏ（ａ）等位基因 Ｌｐ Ｂ、 Ｌｐ Ｓ１、 Ｌｐ Ｓ２ 可能是易发脑梗塞者的基因标志。     

慢性咽炎动物模型研究

为探索慢性咽炎动物模型的复制以供实验研究之用,根据慢性咽炎的临床诊断标准用氨水在咽部喷雾和松节油在其粘膜下注射的方法研制慢性咽炎的动物模型,并从症状体征,血液学,组织学及超微结构等方面进行了观察。     

不同方法制作犬腹主动脉瘤模型的比较

目的：探讨用于检验带膜记忆合金支架血管腔内搭桥治疗动脉瘤的模型。方法：分别以实验动物腹直肌后鞘、Ｄａｃｒｏｎ补片、不同口径的Ｄａｃｒｏｎ人血管及球囊导管材料,采用四种不同手术方法制作腹主动脉瘤模型。结果：１１例动物１０例模型制作成功,１例死亡,１月后造影检查发现９例的动脉瘤模型形态满意,１例动脉脉瘤扩张程度较差。结论;以腹阗甩垢鞘为材料制作动脉瘤模型具有取材方便,操作简便、不易漏血、无异物反应的优     

局灶性脑缺血大鼠模型的研究

采用开颅电凝阻断大鼠一侧大脑中动脉并结扎同侧颈总动脉的方法,复制了局灶性脑缺血模型,应用神经检查分级评估法,组织化学染色和计算机图象处理系统,证实了该模型的可靠性。     

新生儿缺氧缺血性脑损伤亚低温干预大鼠模型的建立

为探讨不同疗程亚低温对新生儿脑损伤的保护作用,建立新生儿缺血缺氧性脑损伤亚 温干预大鼠模型,先在７日龄清洁级ＳＤ大鼠上以右颈总动脉结扎术和吸入低氧浓度气体法制备缺血缺氧性脑损伤（ＨＩＢＤ）模型,再将其随机分为室温恢复组（ＲｏＴ组,ｎ＝４４）和３种疗程（２４ｈ,４８ｈ,７２ｈ）的亚低温干预组（Ｈｙ２４组,ｎ＝２６,Ｈｙ４８组,ｎ＝１４,Ｈｙ７２组,ｎ＝２０）。亚低温干预期间采用配方奶喂养,并监测脑温