Cathodes for fuel cells using proton-conducting Li2SO4–Al2O3 electrolyte

The performances of three widely different cathode materials (Pt, strontium-doped lanthanum manganite (LSM), and NiO) have been compared for use with proton conducting Li₂SO₄–Al₂O₃ composite electrolyte, using H₂S–air and H₂–air fuel cells operating at 600 °C. Surface analysis and electrochemical techniques were used to characterize fresh and used electrode materials. Pt or LSM cathodes each became covered with Li₂SO₄ and Al₂O₃ and, as a consequence, the fuel cells showed poor performance. In contrast, the NiO cathode catalyst did not become covered with Li₂SO₄ and good fuel cell performance was achieved. Exceptionally good current densities of over 100 mA/cm² and power densities of over 30 mW/cm² were obtained for H₂S–air fuel cells having Mo–Ni–S anode catalysts. Slight agglomeration of NiO particles during fuel cell operation had only a minor effect on performance.     

四氧嘧啶诱发糖尿病大鼠血管紧张素的变化

实验观察了四氧嘧啶诱发糖尿病大鼠连续饲养１１０ｄ后体内肾素一血管紧张素系统的变化。结果表明，血浆和心脏的血管紧张素Ⅱ含量无明显变化，而肾脏的ＡｎｇⅡ含量却明显低于正常对照组。另外，心脏的心钠素（ＡＮＰ）含量在糖尿病大鼠与正常对照组之间无差别，血中的糖化血红蛋白含量基本无变化。上述结果表明，糖尿病大鼠早期心脏可能无明显损伤，而肾脏的肾素一血管紧张素系统活性降低。     

慢性放射性溃疡32例治疗体会

慢性放射性溃疡治疗难度较大，为寻求适当的治疗方案提高疗效，对既往病例进行了回顾。总结了自１９８３年以来，慢性放射性溃疡３２例的治疗经验，对发病原因、部位、病变特点及治疗方法作了分析。３１例治愈、创面Ｉ期愈合２６例，Ⅱ期愈合５例，死亡１例。认为须提高对放射溃疡的重视和认识，针对不同的病变部位，深度及其特点，采取不同的清创方法及相应的修复措施。为改善局部血循环，应以皮瓣或肌皮瓣治疗为首选。     

ACTIVIT OF HUMAN PLACENTAL GAMMA GLOBULININ BLOCKING IMMUNE FUNCTIONS IN VITRO AND IN ABROGATING THE XENOGENEIC, LOCAL GRAFT-VERSUS-HOST-REEACTEON

In order to understand the mechanism of immunosuppression caused by infusion of placental gamma globulin (PGG) in patients with renal allografts, rheumatoid arthritis, and graft – versus –host disease (GCHD) following bone marrow transplantation (BMT) ,we have examined the effect of PGG in vitro and in a model of the xenogeneic , local graft –ver- sus – host reaction (LGVHR) .PGG inhibited lymphocyte proliferation in mixed lymphocyte cultures (MLC) (P<0.005) and depressed interleukin -2 (IL-2) levels in such cultures at 72 hours (P<0.01) . In contrast phytohemagglutinin (PHA) –and pokeweed mitogen (PWM) –induced T and B lymphocyte blastogenesis was not affected by such PGG treatment .PGG treatment .PGG neither decreased the [3H] TdR pulse incorporation in unstimulated lymphocytes nor affected cell viability .Cell cycle analysis by flow cytometry showed that PGG reduced the percentage of cells in S and G2, M phases during the MLC, but did not alter cell cycling during PWM-stimulated proliferation . An immunosuppressive effect of PGG on the LGCHR was tested in a model of intracutaneous transplantation of PGG –treat human lymphocytes into cyclophosphamide – immunosuppressed rats. Lymphoprep – separated human tonsillar lymphocytes were incubated with RPMI-1640 buffer containing：（1）PGG,4mg/ml,(2) human plasma albumin,4mg/ml,(3)mitomycin-C,25ug/ml, or (4) no additive. Cell of each preparation (3x107cells in 0.1ml) were injected intracutaneously into cyclophosphamide-treated male rats at separate abdominal locations. A fifth site received only the buffer solution. Five days after injection of cells ,each rat received [125 I]IUdR (10uCi) intraperitoneally and was killed after 5 hours. For each site of injection, the diameters of induration were measured and 125 I was counted . There was no difference between buffer – treated and a ibumin – treated groups either in the diameter of the area of induration (t=0.66;P>0.5)or in radioactive counts(t=0.22;P>0.05).In the PGG –treated group, the induration and radioactivity measurements were significantly less than in control groups (t=3.72 and P<0.1;t=2.62 and P<0.02,respectively ) Cytophilic antibodies in PGG were thought to inhibit an early phase of T cell activation, and not to be cytotoxicity .In the LGVHR, the immune response might be abrogated either by immuno- regulatory suppression of T cell function or by toxicity to the infused lymphoid cells. For some clinical purposes, immuno- modulating, human antibodies might be preferred to murine, monoclonal antibodies.     

Stability of poly(D,L-lactide-co-glycolide) and leuprolide acetate in in-situ forming drug delivery systems.

In-situ forming drug delivery systems are prepared by dissolving a drug and a biodegradable polymer (poly(D,L-lactide-co-glycolide), PLGA) in a biocompatible organic solvent (In-situ implant, ISI) or further emulsified into an external phase (oil or aqueous solution), resulting in oil-in-oil or oil-in-water emulsions (In-situ forming microparticles, ISM). The chemical stability of PLGA and the drug is a major concern. In this study, the stability of PLGA and leuprolide acetate in the in-situ forming systems and lyophilized sponges was investigated. The degradation of PLGA increased with increasing storage temperature and water content in the biocompatible solvents. A faster degradation occurred in polar protic solvents (2-pyrrolidone, PEG 400, triethyl citrate) than in polar aprotic solvents (N-methyl-2-pyrrolidone, DMSO, triacetin, ethyl acetate). The presence of leuprolide acetate significantly accelerated PLGA degradation, especially in solution state. PLGA was stable in oily suspensions at 4 degrees C and degraded only slightly faster than solid powder at 25 degrees C. No interaction between the oils and the PLGA was observed as indicated by an unchanged T(g) of approx. 47 degrees C. PLGA underwent a slight degradation at 4 degrees C after 150 days in water and saturated sodium chloride solution. The degradation was slower in saturated sodium chloride solution than in water at 25 degrees C. Residual acetic acid in lyophilized sponges facilitated the PLGA degradation in contrast to dioxane. Leuprolide acetate did not affect the PLGA stability negatively. However, lidocaine significantly enhanced the polymer degradation in the sponges. Finally, leuprolide acetate was chemically stable in the sponges, the oils and the polymer solutions in suspension state, but unstable (aggregation) when dissolved in the polymer solutions and stored at 25 degrees C and 40 degrees C.     

电脑比配色仪与比色板之间的相近性分析

目的：通过对比色记录的分析，比较Vita比色板、松风Vintage Halo比色板和电脑比配色仪之间的相近性和差异性。方法：随机抽取100名年龄在21～24岁的本地在校大学生，由男女两位测试者使用电脑比配色仪、Vita比色板和松风Vintage Halo比色板对被测试者的左上中切牙进行比色分析。结果：三种比色方法均以A色调最为集中，占总数的55％以上。其次是D色调占总数20％以上。男女测试者的选色在A、R、VR．系列中无明显差异。结论：电脑比配色仪、Vita比色板、松风Vintage Halo比色板均不能完全覆盖本地区青年天然中切牙的色度特征，只在A色调系列中重复率较高。     

管状膨体聚四氟乙烯用于组织工程支架材料的动物实验研究

目的：研究膨体聚四氟乙烯(ePTFE)植入动物体内后与机体的关系。方法：管状膨体聚四氟乙烯两端闭合，内充DMEM培养液，埋入家兔皮下，观察宿主生命情况，于术后1、2、4、6周取出标本，行大体及光镜下观察。结果：家兔在植入膨体聚四氟乙烯材料及DMEM培养液后存活情况良好，DMEM培养液在1周时即已完全无色透明；4周时膨体聚四氟乙烯与周围组织有粘连，6周时粘连紧密；光镜下观察，各时间点材料间隙均可见着色，1周时可见少量淋巴细胞浸润，无血管及组织细胞。材料内壁未见细胞附着。结论：植入膨体聚四氟乙烯材料及少量DMEM培养液对宿主动物存活无影响；管内外液体可相互交通，管状膨体聚四氟乙烯可作为组织工程化尿道的支架材料。     

不同脑缺血和再灌流过程中大鼠脑组织NO含量的动态变化

采用线栓法制成大鼠大脑中动脉梗塞 ( MCAO)模型 ,依 Hb O2 - NO法测定持续性脑缺血和缺血 /再灌流脑组织内 NO含量的变化 ,以探讨不同脑缺血和再灌流过程中 NO的变化规律及其意义。结果 :缺血 3小时受损脑组织 NO水平即增高 ,再灌流后 NO逐步升高 ,而持续性缺血状态下 NO则表现降低后再升高的变化。虽然两组 NO在 7天时均有明显降低 ,但仍高于缺血前水平。认为持续性脑缺血和缺血 /再灌流情况下 NO的变化规律有所不同 ,与缺血脑组织的缺氧及产生 NO所需底物供应缺乏有关 ,且可能与脑组织的损害密切相关