长效重组人超氧化物歧化酶的研制及其辐射防护作用

选用无毒、无免疫原性的高分子化合物聚乙二醇(PEG)为修饰剂,以活性酯法制备出PEG- 重组人超氧化物歧化酶(PEG-rh SOD)共价结合物.修饰酶的生物半衰期为15h,比修饰前延长了90倍,对酸、碱、热的耐受力明显高于修饰前.用照射小鼠的活存率评价了PEG-rhSOD的辐射防护作用.小鼠受8.5Gy γ射线照射前1h腹腔注射30万U/kg PEG-rh SOD,可提高活存率42%,与未修饰的rhSOD相比,活存率提高14%.实验仍在进行中.     

蛋白质多肽药物聚乙二醇定点修饰的研究进展

聚乙二醇修饰可以很好地解决蛋白多肽药物难溶性、稳定性差、半衰期短、毒性大、免疫原性等问题,其中的聚乙二醇定点修饰方式更具优势.本文着重介绍聚乙二醇在蛋白多肽药物中的N端氨基、巯基、羧基和糖类残基及N端氧化后的定点修饰方式的研究进展.     

长效重组人超氧化物歧化酶的研制及其辐射防护作用研究

选用无毒、无免疫原性的高分子化合物聚乙二醇（ＰＥＧ）为修饰剂，以活性酯法制备出ＰＥＧ－重组人超氧化物歧化酶（ＰＥＧ－ｒｈＳＯＤ）共价结合物。修饰酶的生物半衰期为１５ｈ，比修饰前延长了９０倍，对酸、硷、热的耐受力明显高于修饰前。用照射小鼠活存率评价了ＰＥＧ－ｒｈＳＯＤ的辐射防护作用。小鼠受８．５Ｇｖｒ射线照射前１ｈ腹腔注射３０万Ｕ／ｋｇＰＥＧ－ｒｈＳＯＤ，可提高活存率４２％，与未修饰的ｒｈＳＯＤ相比，活存率提高１４％。     

甲氧基聚乙二醇修饰几种红细胞稀有血型抗原的初步研究

目的：研究用甲氧基聚乙二醇(mmthoxy polyethylene glycol，mPEG)修饰红细胞稀有血型抗原，为制备通用型血寻找可能的途径。方法：用3种具有不同瑞基的mPEG修饰红细胞，观察其对红细胞表面4种稀有血型抗原的修饰效果及对红细胞结构、功能和存活期的影响。结果：实验表明，在1．0mmol／L时mPEG-BTC(苯并三唑碳酸酯端基PEG)就可以使红细胞表面Jk^a，Jk^b，k和P1抗原性消失，而对红细胞形态、渗透脆性、自身溶血、乙酰胆碱酯酶、胆固醇、ATP、2，3-DPG含量、变形性以及存活期无影响，其他2种mPEG对红细胞修饰效果不好。结论：mPEG-BTC(可有效遮蔽红细胞表面的稀有血型抗原，对其结构、功能及存活期无影响，本实验为mPEG包裹法制备通用型血提供了有力的实验证据。     

肽质量指纹图谱中实验因素引起的氨基酸修饰以及相应肽段的质量变化

目的：肽质量指纹图谱是蛋白质组研究．中最重要的蛋白鉴定手段之一，而氨基酸残基的化学修饰会导致图谱中肽质量的改变。本文对实验性因素可能引起的这种质量改变进行了较为系统的观察和小结。方法：本文分析了多个标准蛋白基于SDS-PAGE分离的肽质量指纹图谱的实验结果，综合报道由各种实验因素引起的氨基酸残基体外化学修饰以及相应的肽质量变化。结果：这些化学修饰至少包括：①半胱氨酸残基丙烯酰胺加合物生成或乙酰基烷基化修饰。相应的肽段质量数分别增加71．04和57．02；②甲硫氨酸残基的氧化修饰，相应肽段质量数增加15．99（单甲硫氨酸氧化）或其倍数（多甲硫氨酸氧化）；③酸性氨基酸残基的成盐反应，相应肽段质量数增加21.98（加钠盐）或37．95（加钾盐）；④酸性氨基酸残基的酯化反应，相应肽段质量数增加14.03（甲醇固定）或28．03（乙醇固定）；⑤碱性氨基酸（赖氨酸）残基与甲醛发生西佛碱反应，相应肽段质量数增加27．99。以上各种氨基酸的体外修饰，以甲硫氨酸的氧化修饰最为常见；酸性氨基酸的酯化反应通常发生在蛋白固定步骤；碱性氨基酸（赖氨酸）的西佛碱反应是由于蛋白质银染时增色剂甲醛的引入。特别注意的是，某些肽段可以同时发生多种化学修饰，使得肽质量指纹图谱的解析复杂化。结论：以上实验因素引起的氨基酸修饰以及相应的肽质量变化在蛋白质数据库检索和蛋白质鉴定时必须加以考虑。     

甲氧基聚乙二醇修饰脐血淋巴细胞抗原的实验研究

用甲氧基聚乙二醇(mPEG)修饰脐血单个核细胞 ,并观察修饰后对淋巴细胞表面某些抗原的遮蔽作用及造血干祖细胞体外集落形成能力的影响。流式细胞仪分析结果表明 ,修饰后的脐血淋巴细胞CD3、CD4和CD8抗原与修饰前相比其相对荧光强度明显下降(P <0 0 1) ,剂量越大 ,遮蔽效果越好。当mPEG的浓度达到 12mg/ml时 ,CD3、CD4和CD8表面抗原被遮蔽达 96 %以上。用 3mg/ml、6mg/ml和 12mg/mlmPEG修饰单个核细胞后在体外人干细胞培养基中培养发现 ,形成CFU GM的数量分别为 2 2 83± 14 4 7、2 2 6 7± 14 6 1和2 5 83± 9 99。与对照组 (2 4 0 0±18 4 2 )相比差异无显著性意义 (P >0 0 5 )。提示mPEG修饰脐血淋巴细胞后几乎可以完全遮蔽其表面抗原 ,但不影响干祖细胞在体外的增殖、分化能力。     

原儿茶醛对叔丁基过氧化氢损伤HepG2细胞的保护作用

目的:考察原儿茶醛(PCA)对氧化损伤HepG2细胞的保护作用及其作用机制.方法:200 μmol/L叔丁基过氧化氢(t-BHP)损伤HepG2细胞,检测不同浓度原儿茶醛对细胞活力、超氧化物歧化酶活性、细胞内还原型谷胱甘肽及活性氧族的影响.结果:200 μmol/L叔丁基过氧化氢可以显著性地损伤HepG2细胞,原儿茶醛给药能够显著提高损伤细胞的活力、提升超氧化物歧化酶的活性、降低细胞内活性氧族的含量、增加细胞内还原型谷胱甘肽的含量.结论:原儿茶醛对HepG2细胞有保护作用,其作用机制可能是通过提高抗氧化酶活性、加快活性氧的清除实现细胞保护作用.     

蛋白质的化学修饰及其医药应用

随着生物工程的发展使许多蛋白质类药物获得的广泛使用，但仍然存在三个问题，一是免疫原性，二是毒副作用，三是在体内半衰期短。蛋白质的化学修饰在一定程度上可以克服上述的问题，如消除抗原性，延长体内作用时间等。因而提高了药蛋白的效率，本文介绍聚乙二醇对蛋白的修饰及其在医药中的应用。     

聚乙二醇修饰对尿激酶原性质的影响

为了延长尿激酶原的半衰期，采用聚乙二醇５０００（ＰＥＧ５０００）对该酶进行了修饰，结果表明，尿激酶原经ＰＥＧ修饰后，在兔体内的半衰期延长了９￣１３倍，同时酶活性也有损失，溶酰胺活性保持６２％，溶纤活性保持３．８％￣１０％。     

Schiff碱稀土金属配合物对辐射导致肿瘤细胞DNA损伤及？…

的　Schiff碱具有抗瘤抑菌活性 ,其抗癌作用与其对肿瘤细胞DNA的破坏有关。方法　利用脉冲电场凝胶电泳 (PFGE)的方法 ,观察了某种Schiff碱稀土金属化合物对肿瘤细胞DNA双链断裂及修复的影响。结果　该化合物能够增加辐射导致的DNA双链断裂的生成 ,并抑制其修复。结论　Schiff碱稀土金属配合物能提高肿瘤细胞对辐射的敏感性 ,为开发放化疗修饰剂提供了新的研究方向     

Status of the lipid peroxidation system in the tissues of rats following a 7-day flight on the Kosmos-1667 biosatellite

Rats flown for 7 days on Cosmos-1667 were for the first time used to measure antioxidative enzymes (superoxide dismutase, glutathione peroxidase, glutathione reductase, catalase), lipid peroxidation products (diene conjugates, malonic dialdehyde, Schiff bases) and tocopherol. Enhanced lipid peroxidation in the heart was completely compensated by activation of antioxidative enzymes. The content of all lipid peroxidation products measured in the liver increased; this was accompanied by a decrease of glutathione peroxidase and an increase of superoxide dismutase activities. It is suggested that lipid peroxidation was activated in response to altered gravity.     

红芪胶囊对辐射损伤大鼠的药效作用研究

目的观察中药红芪胶囊对^60Co-γ辐射损伤大鼠的防护效果。方法将大鼠进行2Gy^60Co-γ全身性照射,照后不同剂量红芪胶囊连续灌胃给药21d,观察其不同时间点（0、4、7、10、14、21d）外周血白细胞和红细胞数,以及脑、肺、血清中超氧化物歧化酶和丙二醛含量的变化。结果辐照后大鼠白细胞、红细胞含量较正常对照组明显降低,脑、肺和血清中丙二醛的含量均较正常对照组明显降低,超氧化物歧化酶活性有升高趋势;辐照给药后,大鼠外周血白细胞数升高,红细胞数降低缓慢,脑和肺组织超氧化物歧化酶活性明显升高,丙二醛含量有降低的趋势。结论红芪胶囊可提高机体氧化和还原反应的比值,清除体内过剩的自由基反应,显著减轻辐射对机体的损伤。     

槲皮素干预实验性慢性肾衰大鼠肾脏一氧化氮超氧化物岐化酶与过氧化脂质变化

目的探讨槲皮素干预实验性慢性肾衰大鼠对肾脏一氧化氮、超氧化物岐化酶和过氧化脂质的影响。方法给实验大鼠饲以含腺嘌呤饲料2个月造成慢性肾衰;干预组经口给予槲皮素100mg/（kg.d）×42d;按试剂盒指定方法测定肾组织一氧化氮、超氧化物岐化酶和过氧化脂质。结果与肾衰对照组比较,干预组大鼠肾脏组织一氧化氮含量显著升高,平均每只肾（570±193）和（263±123）nmol,超氧化物岐化酶活性显著升高,平均每只肾（7.68±2.98）和（3.26±2.63）Ku,过氧化脂质量亦显著增加,平均每只肾（103.3±16.1）和（39.2±17.5）nmol,肾组织细胞核因子-κBP65丢失情况明显减轻。结论槲皮素干预可显著提高实验性慢性肾衰大鼠肾脏一氧化氮、超氧化物岐化酶和过氧化脂质,提示其可保护肾脏细胞及抗氧化,减轻细胞损伤。     

Workshop on Biological Applications of X‐ray Microscopy and ImagingAdvanced Photon Source,Argonne National Laboratory,Argonne, IL,USA, 28–29 April 2003

Remarkably, apoptosis was induced by gamma-ray-irradiation in peritoneal resident macrophages (PRM) of C3H mice, but not other strains of mice. The mechanism of this strain-specific apoptosis induction was studied. Apoptosis in PRM was detected microscopically. Various radical scavengers were examined to identify the critical radicals involved in apoptosis induction. Intracellular peroxide levels were measured with a redox-sensitive dye, 2’,7′-dichlorofluorescin diacetate (DCFH). Superoxide dismutase or catalase was introduced into the cells using commercially available Hemagglutinating Virus of Japan (HVJ) envelope vector kit. The enzyme activity of superoxide dismutase was also measured. Radiation-induced apoptosis in C3H mouse PRM was significantly suppressed by treatment with a pharmacological scavenger of superoxide anion, Tiron, but not with other radical scavengers. Intracellular peroxide levels were not elevated by irradiation at doses high enough to induce apoptosis maximally. Radiation-induced apoptosis in C3H mouse PRM was markedly suppressed by superoxide dismutase introduced into the cells using the HVJ envelope vector, but not catalase. The enzyme activity of superoxide dismutase in C3H mouse PRM was comparable with that in B6 mouse PRM. It was concluded that superoxide played the major role in radiation-induced apoptosis in the C3H mouse PRM and that cellular responses downstream or unrelated to superoxide might be responsible for the strain difference in radiation-induced apoptosis of mouse PRM.     

Radiation-induced apoptosis in peritoneal resident macrophages of C3H mice: selective involvement of superoxide anion, but not other reactive oxygen species

Remarkably, apoptosis was induced by gamma-ray-irradiation in peritoneal resident macrophages (PRM) of C3H mice, but not other strains of mice. The mechanism of this strain-specific apoptosis induction was studied. Apoptosis in PRM was detected microscopically. Various radical scavengers were examined to identify the critical radicals involved in apoptosis induction. Intracellular peroxide levels were measured with a redox-sensitive dye, 2',7'-dichlorofluorescin diacetate (DCFH). Superoxide dismutase or catalase was introduced into the cells using commercially available Hemagglutinating Virus of Japan (HVJ) envelope vector kit. The enzyme activity of superoxide dismutase was also measured. Radiation-induced apoptosis in C3H mouse PRM was significantly suppressed by treatment with a pharmacological scavenger of superoxide anion, Tiron, but not with other radical scavengers. Intracellular peroxide levels were not elevated by irradiation at doses high enough to induce apoptosis maximally. Radiation-induced apoptosis in C3H mouse PRM was markedly suppressed by superoxide dismutase introduced into the cells using the HVJ envelope vector, but not catalase. The enzyme activity of superoxide dismutase in C3H mouse PRM was comparable with that in B6 mouse PRM. It was concluded that superoxide played the major role in radiation-induced apoptosis in the C3H mouse PRM and that cellular responses downstream or unrelated to superoxide might be responsible for the strain difference in radiation-induced apoptosis of mouse PRM.     

电离辐射对小鼠血和肝细胞生物氧化酶活性的影响

报道了经不同剂量（３，６，９和１２Ｇｖ）照射后小鼠血液和肝细胞浆内生物氧化酶活力的变化。结果显示：随着受照剂量的增加，血液和肝细胞浆内总ＳＯＤ、铜锌ＳＯＤ、谷胱甘肽过氧化物酶和过氧化氢酶活力明显降低，而锰ＳＯＤ含量没有明显变化。血液和肝细胞浆内脂质过氧化物在受照大剂量组明显增加。上述结果提示：电离辐射对生物氧化酶活力有明显影响。其影响程度与受照剂量有关。受照后生物氧化酶活力降低是脂质过氧化物升高的主要原因。     

不同训练负荷对大鼠骨骼肌超微结构及线粒体功能的影响

 目的 研究不同训练负荷下,大鼠骨骼肌超微结构及线粒体呼吸链酶复合体Ⅰ、Ⅱ、Ⅲ、Ⅳ和总超氧化物歧化酶(total superoxide dismutase, T-SOD)、锰超氧化物歧化酶(manganese superoxide dismutase, Mn-SOD)和铜锌超氧化物歧化酶(copper zincsuperoxide dismutase, CuZn-SOD)的变化。方法 建立SD大鼠跑台训练模型,将24只大鼠随机分为正常对照组、有氧训练组、无氧训练组,每组8只,正常对照组大鼠笼内正常生活,其他两组分别进行有氧和无氧训练4周,有氧训练时采用递增负荷训练,无氧训练时采用高速训练。采用透射电镜观察骨骼肌形态及线粒体变化。用可见分光光度计检测大鼠骨骼肌线粒体呼吸链酶复合体Ⅰ、Ⅱ、Ⅲ、Ⅳ,以及T-SOD、Mn-SOD和CuZn-SOD活性。结果 相比正常对照组,电镜下有氧训练组线粒体数量增多,三联体结构明显。无氧训练组中可见大量发生肿胀的线粒体,电子密度较正常染色体低;明带与暗带界限不清,粗细肌丝排列紊乱。相比正常对照组,有氧训练组大鼠骨骼肌线粒体呼吸链酶复合体Ⅰ、Ⅱ、Ⅲ、Ⅳ,以及T-SOD、Mn-SOD和CuZn-SOD活性均显著上升(P<0.05);无氧训练组线粒体呼吸链酶复合体Ⅰ、Ⅱ、Ⅲ、Ⅳ以及T-SOD和Mn-SOD活性显著下降(P< 0.05),CuZn-SOD活性[(2.68±0.61)×10³ nkat/mgprot]与正常对照组活性值[(3.73±1.24)×10³ nkat/mgprot]相比,差异无统计学意义(P> 0.05)。结论 不同训练负荷可以改变大鼠骨骼肌线粒体功能,导致抗氧化功能发生相应变化,从而对骨骼肌形态产生较大影响。有氧训练可以改善骨骼肌形态结构和线粒体功能,减轻机体疲劳。     

The relationship of oxygen uptake to superoxide dismutase and catalase activity in human skeletal muscle

A considerable amount of evidence now makes it clear that aerobic tissues require an elaborate enzyme system to remove the harmful reaction products of oxygen reduction. A portion of this protective system has been studied in human muscle and rat tissues. The VO2 max as well as the superoxide dismutase and catalase activity of vastus lateralis muscle of 12 healthy, male subjects was measured. The subjects with a high aerobic capacity (VO2 max greater than 60 ml . kg-1 . min-1) had significantly greater levels of both superoxide dismutase and catalase. There was also a linear relationship between both superoxide dismutase and catalase and VO2 max. The tissue oxygen consumption, and enzyme activity of the liver, heart, lung, and gastrocnemius from 24 rats was also studied. There VO2 and tissue enzyme activity of both superoxide dismutase and catalase.     

Radioprotective effect of endogenous melatonin secretion associated with the circadian rhythm in irradiated rats

Abstract

Purpose: We investigated the radioprotective effect of endogenous melatonin release at different times associated with the circadian rhythm on head and neck radiotherapy.

Materials and methods: Two groups of animals were subjected daily to 8?Gy single fraction radiotherapy in the head and neck region from 5:00 to 6:00 (the morning group) or from 19:00 to 20:00 (the evening group). Corresponding untreated groups served as controls. Submandibular glands from rats sacrificed on the seventh day after irradiation were assessed biochemically and histopathologically. Melatonin, malondialdehyde and superoxide dismutase levels in blood collected immediately prior to irradiation were measured with rat-specific ELISA kits.

Results: In irradiated rats, melatonin, malondialdehyde and superoxide dismutase levels were significantly higher in the evening group than in the morning group. In nonirradiated rats, melatonin and superoxide dismutase levels were significantly higher in the evening group than in the morning group. The areas of seromucous acinar cells were similar between the irradiated and nonirradiated evening groups, but the area was higher in the evening irradiated group than in the morning irradiated group.

Conclusion: Consideration of endogenous melatonin secretion associated with the circadian rhythm may offer new therapeutic solutions for the complications of head and neck radiotherapy.     

Selected biochemical parameters of blood serum in soldiers committing self-mutilation

OBJECTIVE: This project attempts to establish a possible link between selected biochemical parameters (cholesterol and triglyceride concentrations and levels of malonyl dialdehyde and superoxide dismutase) in soldiers with autoaggressive behaviors. MATERIALS AND METHODS: The study involved 33 soldiers treated for self-aggressive behavior from July 1, 1998, to June 30, 1999. Average patient age was 20.7 years. The control group consisted of 21 soldiers hospitalized for mental disturbances but not showing autoaggressive tendencies. Total cholesterol and activity of platelets, considering the generation of free radicals and triglyceride concentration levels, were determined in the blood serum of members of both groups. RESULTS: The results indicate significantly lower concentrations of total cholesterol in the serum of soldiers showing self-aggressive behaviors. Also, increased concentrations of malonyl dialdehyde in blood platelets and decreased superoxide dismutase activity were found in individuals prone to autoaggression. CONCLUSION: The results suggest that the dysfunction of oxidation-reduction processes in brain tissue leads to excessive generation of free radicals, which can cause brain cell damage and disturb metabolic processes, resulting in mental disturbances that may constitute a background for self-aggressive behavior. The decreased activity of superoxide dismutase is a major factor in the observed oxidation-reduction disturbances.