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11.
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. 相似文献
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电脑比配色仪与比色板之间的相近性分析 总被引:1,自引:0,他引:1
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。 相似文献
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Objective To evaluate the clinical effect of placing double J stent using a ureteroscope in early managing ureterovaginal fistula.Methods Twenty-eight patients cases with ureterovaginal fistula from 2002 to 2008 were treated early with placing double J stent using a ureteroscope and the clinical data were reviewed.Results Twenty-two of 28 cases were treated and double J stent was placed in them by a uretero-scope and 75% (21/28)of cases were cured.Four of 21 cases were treated twice by a ureteroscope and were cured finally.7 cases with failure ureterovaginal treatment underwent ureterocystostomy and were cured.The follow-up from 6 months to 33 months (average 10.1±6.4 months)showed that all of the 28 cases had been cured and had no urinary fistula.Conclusion Placing double J stent using a ureteroscope is the first choice of operative procedure for the early treatment of ureterovaginal fistula. 相似文献
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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 总被引:6,自引:0,他引:6
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。 相似文献
18.
Lei Ding Christopher Wilke Bobby Xu Xiaoliang Xu Wim van Drongelen Michael Kohrman Bin He 《Journal of clinical neurophysiology》2007,24(2):130-136
SUMMARY: It is desirable to estimate epileptogenic zones with both location and extent information from noninvasive EEG. In the present study, the authors use a subspace source localization method (FINE), combined with a local thresholding technique, to achieve such tasks. The performance of this method was evaluated in interictal spikes from three pediatric patients with medically intractable partial epilepsy. The thresholded subspace correlation, which is obtained from FINE scanning, is a favorable marker, which implies the extents of current sources associated with epileptic activities. The findings were validated by comparing the results with invasive electrocorticographic (ECoG) recordings of interictal spike activity. The surgical resections in these three patients correlated well with the epileptogenic zones identified from both EEG sources and ECoG potential distributions. The value of the proposed noninvasive technique for estimating epileptiform activity was supported by satisfactory surgery outcomes. 相似文献
19.
改良W形回肠代膀胱术的疗效观察(附36例报告) 总被引:5,自引:0,他引:5
目的 :探讨改良W形回肠代膀胱术的疗效。方法 :对 36例膀胱肿瘤患者行根治性膀胱切除、W形回肠代膀胱术 ,并对术式进行改进。结果 :36例手术时间平均 4 .2h。术后 31例随访 4~ 19个月 ,平均 10 .6个月 ,无严重并发症 ,均无瘤生存。患者一般于术后 3周自主可控性排尿 ,日间尿控率为 10 0 % ,术后 3、6、12个月夜间尿失禁发生率分别为 2 2 .5 %、11.1%及 6 .2 %。术后 6个月尿动力学检查膀胱容量 (36 0± 30 )ml,最大尿流率 (13.6± 2 .6 )ml/s,剩余尿量 (11.5± 5 .8)ml,充盈期膀胱压力明显低于尿道闭合压。新膀胱造影发现新膀胱呈球形 ,完全位于盆腔 ,未见输尿管反流。B超及IVU检查发现原上尿路积水 4例均明显减轻 ,其余未发现输尿管狭窄和上尿路积水征象。无高氯性酸中毒 ,肾功能正常。结论 :改良W形回肠代膀胱术手术时间短 ,操作简单 ,创伤轻 ,并发症少 ;新膀胱容量大 ,内压低 ,顺应性好 ,功能接近于正常膀胱 ,保持原位排尿 ,明显提高了患者术后生活质量 ,值得临床推广应用。 相似文献
20.
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 总被引:12,自引:0,他引:12
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 相似文献