Serine hydroxymethyltransferase isoforms are differentially inhibited by leucovorin: characterization and comparison of recombinant zebrafish serine hydroxymethyltransferases.

Serine hydroxymethyltransferase (SHMT) provides activated one-carbon units required for the biosynthesis of nucleotides, protein, and methyl group by converting serine and tetrahydrofolate to glycine and N(5),N(10)-methylenetetrahydrofolate. It is postulated that SHMT activity is associated with the development of methotrexate resistance and the in vivo activity of SHMT is regulated by the binding of N(5)-CHO-THF, the rescue agent in high-dose methotrexate chemotherapy. The aim of this study is to advance our understanding of the folate-mediated one-carbon metabolism in zebrafish by characterizing zebrafish mitochondrial SHMT. The cDNA encoding zebrafish mitochondrial SHMT was cloned, overexpressed in Escherichia coli, and purified with a three-step purification protocol. Similarities in structural, physical, and kinetic properties were revealed between the recombinant zebrafish mitochondrial SHMT and its mammalian orthologs. Surprisingly, leucovorin significantly inhibits the aldol cleavage of serine catalyzed by zebrafish cytosolic SHMT but inhibits to a lesser extent the reaction catalyzed by the mitochondrial isozyme. This is, to our knowledge, the first report on zebrafish mitochondrial folate enzyme as well as the differential inhibition of leucovorin on these two SHMT isoforms. Western blot analysis revealed tissue-specific distribution with the highest enrichment present in liver for both cytosolic and mitochondrial SHMTs. Intracellular localization was confirmed by confocal microscopy for both mitochondrial and cytosolic SHMTs. Unexpectedly, the cytosolic isoform was observed in both nucleus and cytosol. Together with the previous report on zebrafish cytosolic SHMT, we suggest that zSHMTs can be used in in vitro assays for folate-related investigation and antifolate drug discovery.     

量化健康教育在CCU住院病人健康教育中的应用

医院健康教育是护理人员通过各种教育形式使病人或家属获得预防疾病、促进康复、保持健康知识的护理活动[1]。它有多种教育形式,本文就量化健康教育与随机健康教育效果进行比较。1对象与方法1.1对象2002年1月—2004年1月,知道自己所患病情,能清楚表达自己意愿的200例CCU住院病人为对象。按随机数字表将200例病人分为实验组和对照组。实验组男68例,女40例,年龄(58.7±6.9)岁;初中及以下35例,高中及以上73例;高血压36例,急性心肌梗死13例,不稳定性心绞痛17例,恶性心律失常27例(行起搏器植入术7例),急性左心衰竭15例。对照组男60例,女32例,年…     

Changes in T .lymphocyte subsets after severe traumatic brain inJury

BACKGROUND： Besides local changes of cranial parenchymal cells, hemorrhage, etc., severe traumatic brain injuries also cause the changes of total body fluid and various functions, and the changes of lymphocytes and T lymphocyte subsets should be paid more attention to. OBJECTIVE： To reveal the changing laws of T lymphocyte subsets after severe traumatic brain injury, and compare with mild to moderate brain injury. DESIGN： A comparative observation. SETTINGS： Department of Neurosurgery, Longgang District Buji People＇s Hospital of Shenzhen City; Central Laboratory of Shenzhen Hospital of Prevention and Cure for Chronic Disease. PARTICIPANTS： All the subjects were selected from the Department of Neurosurgery, Longgang District Buji People＇s Hospital of Shenzhen City from August 2002 to August 2005. Thirty patients with severe brain injury, whose Glasgow coma score （GCS） was ≤ 8 points, were taken as the experimental group, including 21 males and 9 females, aging 16 - 62 years. Meanwhile, 30 patients with mild traumatic brain injury were taken as the control group （GCS ranged 14- 15 points）, including 18 males and 12 females, aging 15 -58 years. All the subjects were in admission at 6 hours after injury, without disease of major organs before injury Informed consents were obtained from all the patients or their relatives. METHODS： （1） The T lymphocytes and the subsets in peripheral blood were detected with immunofluorescent tricolor flow cytometry at l, 3, 7 and 14 days after injury in both groups. （2） The conditions of pulmonary infections were observed at 4 days after injury. The differences of measurement data were compared with the t test. MAIN OUTCOME MEASURES： Changes of T lymphocytes subsets at 1 - 14 days after severe and mild or moderate traumatic injury. RESULTS： Finally, 28 and 25 patients with mild to moderate traumatic brain injury, whereas 25 and 21 patients with severe traumatic brain injury were analyzed at 7 and 14 days respectively, and the missed ones died due to the development of disease. （1） Changes of T lymphocyte subsets： At 1 and 3 days after injury, CD3, CD4, CD8, CD4/CD8 began to decrease, whereas CD8 increased in the experimental group, which were very significantly different from those in the control group （t =2.77 - 3.26, P 〈 0.01）, and began to recover at 7 days, which were significantly different from those in the control group （t = 2.06 - 2.24, P 〈 0.05）, and generally recovered to the normal levels at 14 days （P 〉 0.05）. （2） Conditions of pulmonary infections： At 4 days after injury, the rate of pulmonary infection was significantly different between the experimental group and control group [73% （22/30）, 0, x2=37.29, P 〈 0.01]. CONCLUSION： Patients with severe traumatic brain injury suffer from damages of cellular immune function at early period （within 7 days）, and they are easily to be accompanied by pulmonary infections.     

新型纳米根管充填材料对成骨细胞生长的影响

通过体外培养的成骨细胞,采用二甲基噻唑二苯基四唑溴盐比色法和流式细胞术对新型纳米根管充填材料(nHA-PA66)作用下的成骨细胞生长情况的变化进行研究,评价其对成骨细胞生长的影响。以该材料的细胞培养基浸提液作用于实验组细胞,对照组采用培养基本身。实验组和对照组成骨细胞的生长情况和细胞周期无显著性差异,表明该新型纳米材料对成骨细胞的生长和细胞周期无不良影响。提示新型纳米根管充填材料的成骨细胞相容性较好,具有用作根充材料的基础。     

一种较好的RNA分离制备方法及其在人胚RNA提取中的应用

以钒基核苷酸复合物为核酸酶抑制剂,从人胚组织中制备总RNA,所得产品几乎不含DNA和蛋白质,经过分离Poly(A)~ mRNA,证明制品有合成cDNA的完整功能,方法比较简捷,适于大量制备以满足分离mRNA 之需,并讨论了此法的优缺点。     

本刊现已实行“中华医学会信息管理平台"在线投稿

本刊的审稿专家可使用同一个用户名作为审稿人进行稿件审理和作者投稿。(3)作者投稿请直接登录中华医学会业务巾心下信息管理平台的稿件远程管理系统，点击“作者在线投稿”。投稿成功后，系统自动发送回执邮件。作者可随时点击“在线查稿”，获知该稿件的审稿情况、处理进展、审稿意见、终审结论等；有关稿件处理的相关结果编辑部不再另行纸质通知。     

靶重建放大扫描对肺孤立性结节病变的诊断意义

目的：探讨靶重建放大扫描技术对肺孤立性结节病变的诊断价值。方法：对63例患者先行常规CT平扫，选定结节处为兴趣区，行薄层靶重建放大扫描，层厚、层距为2mm，FOV为160。结果：42例恶性病变中有37例表现为深分叶，占88．1％；21例良性病变中有15例表现为浅分叶，占71．4％。恶性结节中15例内部出现条状低密度支气管征；7例出现血管集中征；8例出现空泡征；病变内部出现液化坏死13例，其中恶性病变ll例。22例出现钙化，包括12例良性病变和10例恶性病变。2例错构瘤内均见小面积脂肪性低密度影。结论：靶重建放大扫描比普通CT扫描可提供更多的信息，对良恶性病变的鉴别诊断有一定价值。恶性病变大多数为深分叶，良性病变大多数为浅分叶或无分叶。     

二氧化碳吸收剂中水分对七氟醚分解反应的影响

目的　研究模拟紧闭反应器内干燥的二氧化碳 (CO2 )吸收剂及自身含水对七氟醚分解的影响。方法　在紧闭反应器 (1 6 0ml)内 ,分别装钠石灰、钡石灰、干燥钠石灰和干燥钡石灰 (各 2 5g)。在密闭状态下注入液态的七氟醚 4 0 0 μl,放入 5 0℃水浴内反应 6h ,分别在 5、1 5、30、4 5、6 0min、以后每 30分钟至 36 0分钟采样 ,用气相色谱法分析。测定七氟醚的分解产物。结果　钠石灰组出现复合物A、B ,在其他组七氟醚产生 5种分解产物。复合物A∶干燥钡石灰 >干燥钠石灰 >钡石灰和钠石灰组。干燥钡石灰组明显高于其他两组 (P <0 0 5 )。复合物B∶干燥钡石灰组 <钡石灰组 <干燥钠石灰组 (P <0 0 5 )。复合物C、D、E ,以干燥钡石灰组最为明显 (P <0 0 5 )。各组均未检测到CO。结论　在 5 0℃的紧闭反应器内 ,七氟醚与干燥的CO2 吸收剂反应剧烈 ,未产生CO ;国产钠石灰优于钡石灰 ,在紧闭容器内自身含水可以抑制分解反应     

桡骨远端关节内骨折外固定器治疗的相关机制和原则探讨

目的 分析和探讨桡骨远端关节内骨折外固定器治疗的相关机制和原则.方法 笔者采用Orthofix外固定器和国产组合式外固定器治疗桡骨远端关节内骨折45例46肢,以齐藤英彦法对资料完整的37例38肢病例进行分型,分析其影像学表现、损伤和治疗相关机制以及特点.结果 各型复位方向和外固定腕关节位置均与致伤暴力方向相反.骨折愈合时间平均为43 d(37～62 d),平均随访时间14个月(3～56个月),按Dienst标准评估腕关节功能及疗效:优21例22肢,良10例10肢,可6例6肢.结论 闭合复位外固定能很好地解决桡骨远端关节内骨折的治疗问题,特别适用于粉碎型关节内骨折.其治疗原则是复位方向及腕关节外固定位置与损伤机制、移位情形相反,个别骨折块辅以切开复位时须强调有限切开,必须重视部分病例伴有的同侧桡骨中远段骨折和同侧尺骨远段骨折的处理.     

丹芎瘢痕涂膜的临床应用研究

目的:本文通过769例病人应用丹芎瘢痕涂膜防治瘢痕增生的治疗效果,为烧烫伤后瘢痕增生提供一种新的治疗手段.方法:我们根据中医、中药活血化淤原理,经多年临床实践研制而成的丹芎瘢痕涂膜,由丹参、川芎等复方组成.药物使用,将丹芎瘢痕涂膜直接均匀涂于瘢痕表面上,形成药膜,次日揭去药膜,重新涂药,每日1次,连续用药5个月.疤痕止痒软化膏对照,每日1次,连续用药5个月.结果:(1)创面愈合后瘢痕刚开始增生者,丹芎瘢痕涂膜治疗组共415例,显效77例,有效323例,总有效率96.39%;疤痕止痒软化膏同体对照组51例,显效0例,有效20例,总有效率39.22%,治疗组显著优于对照组.(2)创面愈合后瘢痕已增生者,丹芎瘢痕涂膜治疗组354例,显效88例,有效257例,总有效率97.46%;疤痕止痒软化膏对照组63例,显效4例,有效34例,总有效率60.32%,治疗组显著优于对照组.(3)丹芎瘢痕涂膜治疗组与疤痕止痒软化膏对照组综合疗效比较,丹芎瘢痕涂膜治疗组769例,显效165例,有效580例,总有效率96.88%;疤痕止痒软化膏对照组114例,显效4例,有效54例,总有效率50.88%,治疗组显著优于对照组.(4)60例丹芎瘢痕涂膜治疗组与同体空白对照组比较,治疗组显效25例,有效34例,总有效率98.33%;对照组显效0例,有效11例,总有效率18.33%;治疗组显著优于对照组.(5)未发现不良反应.结论:经769例病人临床应用丹芎瘢痕涂膜,并与已知疤痕止痒软化膏比较,丹芎瘢痕涂膜治疗效果显著优于疤痕止痒软化膏,丹芎瘢痕涂膜是一种安全、有效、新的创面瘢痕外用药.