聚乙二醇在猪组织工程瓣膜制备中的应用

目的:观察聚乙二醇法在组织工程瓣膜准备中的应用价值,比较聚乙二醇去细胞前后组织工程瓣膜的物理特性。方法:实验于2005-10/2006-03在华中科技大学同济医学院基础医学院生物化学系实验室完成。①实验分组:取猪10只,由于猪主动脉瓣为三叶瓣结构,共取得瓣叶组织30个,麻醉后宰杀取其心脏动脉瓣膜,分为去细胞组和对照组,每组各15个。②实验方法:去细胞组用聚乙二醇和DNase I处理;瓣叶组织放入1kg/L聚乙二醇,室温下浸泡30～45min,振荡器加以振荡;含抗生素磷酸盐缓冲液浸泡24h,反复3次洗脱;以5×104U/L DNase I液浸泡处理1h;对照组仅以含抗生素磷酸盐缓冲液浸泡24h,反复3次洗脱。③实验评估:苏木精-伊红染色、扫描电镜观察去细胞情况,吸光度(A)值,计算去细胞率(%)=(对照组A值-去细胞组A值)/对照组A值×100%。猪去细胞瓣膜条置于力学测试仪测定最大负荷、最大应力、最大应变和弹性模量。结果:纳入猪10只,均进入结果分析。①去细胞组织形态学观察:去细胞组猪瓣膜组织中看不到细胞成分,且细胞外基质结构保存完整,胶原纤维排列整齐,无明显断裂,仍呈波浪状平行排列,结构紧凑,弹性纤维结构清晰,组织无明显水肿。②DNA含量分析:聚乙二醇处理后去细胞百分率为95.32%。③生物力学检测:与对照组比较,去细胞组瓣膜组织最大负荷[(12.586±1.693),(10.242±1.435)N,P>0.05]、最大应力[(2.346±0.342),(1.877±0.572)N/mm,P>0.05]、弹性模量(15.152±1.579,14.549±0.678,P>0.05)、最大应变[(31.685±7.533),(28.118±6.045)mm/N,>0.05]等均无显著差异。P结论:聚乙二醇法去除细胞完全,细胞外基质保存完整,对组织机械性能无明显影响,适于构建组织工程瓣膜。     

IMP dehydrogenase deficiency in Leishmania donovani causes a restrictive growth phenotype in promastigotes but is not essential for infection in mice

Leishmania cannot synthesize purines de novo and therefore must scavenge purines from its host for survival and growth. Biochemical and genomic analyses have indicated that Leishmania species express three potential routes for the synthesis of guanylate nucleotides: (1) a two-step pathway that converts IMP to GMP; (2) a three-step pathway that starts with the deamination of guanine to xanthine, followed by phosphoribosylation to XMP and then conversion to GMP; or (3) direct guanine phosphoribosylation by HGPRT. To determine the role of the first of these pathways to guanylate nucleotide synthesis, an L. donovani line deficient in IMP dehydrogenase (IMPDH), the first step in the IMP to GMP pathway, was constructed by targeted gene replacement. The Δimpdh lesion triggered a highly restrictive growth phenotype in promastigotes in culture but did not impact parasitemias in mice. The dispensability of IMPDH in vivo is the first definitive demonstration that intracellular L. donovani amastigotes have access to a sufficient pool of guanine, xanthine, or guanylate precursors from the host.     

Oral putrescine restores virulence of ornithine decarboxylase-deficient Leishmania donovani in mice

Administration of putrescine as a 1% solution in the drinking water ameliorated the profound loss of virulence exhibited by ornithine decarboxylase (ODC) deficient Leishmania donovani in mice. Furthermore, supplying α-difluoromethylornithine, an ODC inhibitor, at 2% in the drinking water reduced but did not eliminate infection with wild type L. donovani in the mouse model. Taken collectively, these findings: (1) demonstrate that oral putrescine can access the phagolysosome of macrophages in which the parasite resides in mice; (2) establish that the loss of virulence due to the Δodc lesion is a consequence of the inability of the mutant parasite to synthesize sufficient polyamines de novo; (3) imply that the L. donovani amastigote cannot access host polyamines in sufficient amounts for survival and growth; (4) and validate ODC as a drug target, although oral administration of DFMO is an unlikely therapeutic paradigm for visceral leishmaniasis.     

The Hong Kong Society of Rheumatology consensus recommendations for the management of gout

Clinical Rheumatology - Gout is one of the most common noncommunicable diseases in Hong Kong. Although effective treatment options are readily available, the management of gout in Hong Kong remains...     

克泻灵片中苦参碱类生物碱的HPLC分析

目的:对克泻灵片中主要有效生物碱定性、定量。完善产品的质量控制及评价手段。方法:采用HPLC,紫外测定波长:220nm。结果:片剂中有有效生物碱以苦参碱类生物碱为主,其中苦参碱和槐定碱含量高,分别占总生物碱的14.2％～31.6％和22.6％～62.7％,其次为槐颗碱和槐胺碱,氧化苦参碱的含量很低。结论:建立了HPLC测定克泻灵片中主要生物碱,方法简便快捷,精密度好,回收率高,可用于制剂及原料的质量控制。     

Complementary medicine: use and attitudes among GPs

BACKGROUND: Information about use and attitudes of GPs towards complementary medicine is required in order to inform the debate about its place within mainstream medicine. There is evidence that public use of complementary medicine is particularly high in the South-West of England. OBJECTIVE: This study aimed to determine the use of, and attitudes towards, complementary medicine among GPs. METHODS: A questionnaire survey was performed of all primary care physicians working in the health service in Devon and Cornwall. RESULTS: Replies were received from 461 GPs, a response rate of 47%. A total of 314 GPs (68%, range 32-85%) had been involved in complementary medicine in some way during the previous week. One or other form of complementary medicine was practised by 74 of the respondents (16%), the two most common being homoeopathy (5.9%) and acupuncture (4.3%). In addition, 115 of the respondents (25%) had referred at least one patient to a complementary therapist in the previous week, and 253 (55%) had endorsed or recommended treatment with complementary medicine. Chiropractic, acupuncture and osteopathy were rated as the three most effective therapies, and the majority of respondents believed that these three therapies should be funded by the health service. A total of 176 (38%) of respondents reported adverse effects, most commonly after manipulation. CONCLUSION: Over two-thirds of the GPs in Devon and Cornwall who responded to the survey had been involved with complementary medicine in some way during the previous week. This figure is higher than the national average. The majority of respondents believed that acupuncture, chiropractic and osteopathy were effective and should be funded by the NHS.