JAK—STAT通路调制NF-κB介导H2O2预处理的细胞保护作用

目的：探讨核因子-κB（nuclearfactor-κB，NF-κB）在H2O2预处理诱导的适应性细胞保护作用中的作用及JAK—STAT通路对NF-κB的调制。方法：在PC12细胞建立H2O2预处理对抗氧化应激（300μmol／LH2O2）损伤细胞的实验模型。应用碘化丙啶（PI）染色流式细胞术检测细胞凋亡率，免疫印迹法（Westem blotting）测定NF-κB和STAT3的表达水平。结果：用1000μmol／L H2O2预处理PC12细胞90min可显著地抑制300panol／L H2O2作用12h引起的细胞凋亡，并明显地上调NF-κB和STAT3的表达，NF-κB抑制剂MG-132（100μmol／L）和JAK2抑制剂AG-490（10izmol／L）均可抑制H2O2预处理引起的适应性细胞保护作用及上调NF-κB表达的作用。结论：JAK-STAT通路调节NF-κB介导的H2O2预处理的细胞保护作用。     

ERK1／2-STAT3通路在H2O2预处理导致的适应性细胞保护中的作用

目的:探讨ERKI/2一STAT3通路在H2O2预处理导致的适应性细胞保护中的作用.方法:在PCI2细胞建立H2O2预处理对抗氧化应激(300 pmot/L H202)损伤细胞的模型.应用Hoechst33258核染色法观察细胞调亡的形态学改变;应用碘化丙啶(P1)染色流式细胞术检测细胞凋亡率;免疫印记法(Western blotting)测定P-ERKI／2和P-STAT3的表达水平.结果:100μmol/L H2O2预处理PCI2细胞90 rain可明显抑制300μmol/LH2O2作用12 h引起的细胞凋亡,并激活ERKl/2和STAT3;ERKI/2抑制剂U0126和JAK2抑制剂AG一490(10μmol/L)均可明显地阻断H2O2预处理引起的细胞保护作用;U0126(10μmol/L)亦能明显地抑制H2O2预处理对STAT3的上调作用.结论:H202预处理能激活PCI2细胞的ERKl/2-STAT3信号转导旁路,这可能是预处理的细胞保护机制之一.     

Survivin在过氧化氢预处理诱导的适应性细胞保护中的作用

目的探讨H2O2预处理对存活素(survivin)表达的影响及存活素在H2O2预处理的适应性细胞保护中的作用。方法在PC12细胞建立H2O2预处理对抗H2O2诱导细胞凋亡的实验模型,应用甲氮甲唑蓝(MTT)法检测细胞存活率,碘化丙啶(PI)染色流式细胞术检测细胞凋亡率,Hoechst染色检测细胞凋亡的形态学改变,免疫印迹法(Westernblot)测定存活素的表达水平。结果用100μmol/LH2O2预处理PC12细胞90min可明显地抑制300μmol/LH2O2作用12h后引起的细胞毒性和细胞凋亡,并可以显著地上调PC12细胞存活素的表达;JAK2抑制剂AG-490不仅可以抑制存活素的表达,而且拮抗H2O2预处理的适应性细胞保护作用。结论存活素是JAK-STAT通路的靶基因,可能在H2O2预处理诱导的适应性细胞保护机制中起着重要的作用。     

JAK-STAT通路调制NF-κB介导H2O2预处理的细胞保护作用

目的：探讨核因子-кB（nuclear factor-кB, NF-кB）在H₂O₂预处理诱导的适应性细胞保护作用中的作用及JAK-STAT通路对NF-кB的调制。方法：在PC12细胞建立H₂O₂预处理对抗氧化应激（300 μmol/L H₂O₂）损伤细胞的实验模型。应用碘化丙啶（PI）染色流式细胞术检测细胞凋亡率，免疫印迹法（Western blotting）测定NF-κB和STAT3的表达水平。结果：用100 μmol/L H₂O₂预处理PC12细胞90 min可显著地抑制300 μmol/L H₂O₂作用12 h引起的细胞凋亡，并明显地上调NF-κB和STAT3的表达，NF-κB抑制剂MG-132（10 μmol/L）和JAK2抑制剂AG-490（10 μmol/L）均可抑制H₂O₂预处理引起的适应性细胞保护作用及上调NF-κB表达的作用。结论：JAK-STAT通路调节NF-кB介导的H₂O₂预处理的细胞保护作用。     

ERK1/2－STAT3通路在H2O2预处理导致的适应性细胞保护中的作用

目的：探讨ERK1/2-STAT3通路在H₂O₂预处理导致的适应性细胞保护中的作用。方法：在PC12细胞建立H₂O₂预处理对抗氧化应激（300 μmol/L H₂O₂）损伤细胞的模型。应用Hoechst33258核染色法观察细胞调亡的形态学改变；应用碘化丙啶(PI)染色流式细胞术检测细胞凋亡率；免疫印记法(Western blotting) 测定p-ERK1/2和p-STAT3的表达水平。结果：100 μmol/L H₂O₂预处理PC12细胞90 min可明显抑制300 μmol/L H₂O₂作用12 h引起的细胞凋亡，并激活ERK1/2和STAT3；ERK1/2抑制剂UO126和JAK2抑制剂AG-490（10 μmol/L）均可明显地阻断H₂O₂预处理引起的细胞保护作用；UO126（10 μmol/L）亦能明显地抑制H₂O₂预处理对STAT3的上调作用。结论：H₂O₂预处理能激活PC12细胞的ERK1/2-STAT3信号转导旁路，这可能是预处理的细胞保护机制之一。     

PI3K/AKT通路介导H_2O_2预处理减轻PC12细胞氧化损伤

目的探讨PI3K/AKT信号通路是否参与H2O2预处理诱导的适应性细胞保护作用。方法体外培养PC12细胞,建立H2O2预处理对抗高浓度H2O2诱导细胞损伤的实验模型。应用甲氮甲唑蓝(MTT)法测定细胞的存活率,比色法测定乳酸脱氢酶(LDH)的活性,碘化丙啶(PI)染色流式细胞术检测细胞凋亡率,免疫印迹法(Westernblot)测定AKT的表达。结果 100μmol H2O2预处理PC12细胞90 min可显著地抑制300μmol H2O2引起的损伤,使细胞存活率从50.2%±4.6%升高至83.8%±3.5%,LDH活性由103%±10.2%下降至68.5%±5.3%,细胞凋亡率由65.5%±4.1%下降至37.1%±2.3%(P<0.01)。100μmol H2O2预处理诱导p-AKT的表达,PI3K抑制剂ly294002阻断了H2O2预处理引起的p-AKT表达。同时ly294002拮抗了H2O2预处理诱导的抗细胞损伤和凋亡作用。结论 H2O2预处理通过PI3K途径引起AKT的活化,PI3K/AKT通路的活化介导了H2O2预处理诱导的适应性细胞保护作用。     

热休克蛋白参与NF-κB介导的H2O2预处理的细胞保护作用

目的探讨热休克蛋白(HSP)是否参与核因子-κB(NF-κB)介导的H2O2预处理的细胞保护作用。方法应用碘化丙啶(PI)染色流式细胞技术(FCM)检测细胞凋亡率,免疫印迹法(Westernblot)测定NF-κB的表达水平,免疫细胞化学染色法测定NF-κB的核转移。结果100μmol/LH2O2预处理PC12细胞90min可显著地抑制300μmol/LH2O2引起的细胞凋亡,并可明显地上调PC12细胞NF-κB的表达及促进NF-κB的核转移,同时也能上调HSP70和HSP90的表达。NF-κB的抑制剂TPCK阻断NF-κB表达,并显著地阻断H2O2预处理的细胞保护作用及HSP70和HSP90的表达。结论HSP70和HSP90参与NF-κB介导的H2O2预处理的适应性细胞保护作用。     

p38丝裂原活化蛋白激酶对H2O2预处理的适应性细胞保护作用的影响

3580不影响H2O2预处理的适应性细胞保护作用.50 μmol/L H2O2具有比H2O2预处理更强的激活p38的作用,H2O2预处理能明显地抑制50 μmol/LH2O2对p38的激活作用.结论 H2O2预处理抑制高浓度H2O2对p38的激活可能是其适应性细胞保护机制之一.     

p38丝裂原活化蛋白激酶对H2O2预处理的适应性细胞保护作用的影响

3580不影响H2O2预处理的适应性细胞保护作用.50 μmol/L H2O2具有比H2O2预处理更强的激活p38的作用,H2O2预处理能明显地抑制50 μmol/LH2O2对p38的激活作用.结论 H2O2预处理抑制高浓度H2O2对p38的激活可能是其适应性细胞保护机制之一.     

热休克蛋白参与PI3K/Akt 介导H2O2 预处理的抗凋亡作用

目的: 探讨热休克蛋白(HSP)是否参与PI3K/Akt信号通路介导的H₂O₂预处理的抗细胞凋亡作用。方法: 利用PC12细胞建立H₂O₂预处理对抗高浓度H₂O₂诱导细胞凋亡的实验模型,分组如下:(1)空白对照组;(2) 损伤组;(3)预处理＋损伤组; (4)LY294002＋预处理＋损伤组;(5) LY294002组;(6) quercetin＋预处理＋损伤组;(7) 17-AAG＋预处理＋损伤组;(8) 溶剂对照组。应用Hoechst 33258染色观察细胞凋亡形态,碘化丙啶(PI)染色流式细胞术检测细胞凋亡率,比色法测定caspase-3的活性,免疫印迹法(Western blotting)测定HSP的表达水平。结果: 100 μmol/L H₂O₂预处理PC12细胞90 min可显著地抑制300 μmol/L H₂O₂引起的细胞凋亡,使caspase-3的活性降低,同时上调HSP70和HSP90的表达。HSP70和HSP90的抑制剂quercetin和17-AAG拮抗H₂O₂预处理的抗细胞凋亡作用。 PI3K抑制剂LY294002不仅拮抗了H₂O₂预处理抗细胞凋亡的作用,并且抑制H₂O₂预处理对HSP70和HSP90的表达上调。结论: PI3K/Akt通路、HSP70和HSP90均参与H₂O₂预处理诱导的细胞保护作用。并且HSP70和HSP90参与PI3K/Akt信号通路介导H₂O₂预处理的抗细胞凋亡作用。     

Oxidative polymerization of 2-(2-butenyl)- and 2-(3-methyl-2-butenyl)-6-methylphenol

2-(2-Butenyl)-6-methylphenol ( 1a ) and 2-(3-methyl-2-butenyl)-6-methylphenol ( 1b ) were oxidatively polymerized in the presence of a copper-pyridine catalyst to yield poly[oxy-2-(2-butenyl)-6-methyl-1, 4-phenylene] ( 2a ) and poly[oxy-2-(3-methyl-2-butenyl)-6-methyl-1,4-phenylene] ( 2b ) with molecular weights >10⁴. The polymerization rates were in the order 1b > 1a > 1a > 2,6-dimethylphenol ( 3 ), and this order agreed with those of the rate constant of the electron-transfer step and of the redox potential. The 2-butenyl and 3-methyl-2-butenyl group in 2 showed enough chemical reactivity for addition of bromine and epoxidation.     

胰高血糖素样肽-2

胰高血糖素样肽GLP 1和GLP 2由小肠和大肠的内分泌细胞产生并分泌。GLP 2通过对胃的动力作用和营养吸收作用保持小肠粘膜上皮的完整 ,对小肠损伤修复等均有重要的调节作用 ,GLP 2在循环中二肽肽酶Ⅳ (DPIV)的作用下氨基末段迅速裂解失去活性 ,并通过肾脏清除。利用这些肽对营养吸收和能量平衡及在糖尿病动物模型和小肠疾病的作用 ,可供临床应用并治疗人类的疾病     

Mutagenicity of two 2-phenylbenzotriazole derivatives, 2-[2-(acetylamino)-4-(diethylamino)-5-methoxyphenyl]-5-amino- 7-bromo-4-chloro-2H-benzotriazole and 2-[2-(acetylamino)-4-(diallylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole and their detection in river water in Japan

We recently detected five 2-phenylbenzotriazole (PBTA)-type mutagens (PBTA-1, PBTA-2, PBTA-3, PBTA-4 and PBTA-6) in concentrates from several rivers that flow in geographically different areas in Japan containing textile-related industries. On the basis of synthesis studies, these five PBTA derivatives were deduced to have originated from the corresponding dinitrophenylazo dyes, which are industrial chemicals used in textile dyeing, via reduction and chlorination. 2-[(2-Bromo-4,6-dinitrophenyl)azo]-5-(diethylamino)-4-methoxyacetanilide (Color Index name Disperse Blue 291, CAS registry no. 56548-64-2) and 2-[(2-bromo-4,6-dinitrophenyl)azo]-5-(diallylamino)-4-methoxyacetanilide (Color Index name Disperse Blue 373, CAS registry no. 51868-46-3) are used in textile dyeing and have 2-[(2-bromo-4,6-dinitrophenyl)azo]-4-methoxyacetanilide moieties in their structures, which are thought to be essential for their conversion to mutagenic PBTA derivatives. In the present study we have synthesized 2-[2-(acetyl-amino)-4-(diethylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-7) and 2-[2-(acetylamino)-4-(diallylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-8) from Disperse Blue 291 and Disperse Blue 373, respectively, by reduction with iron powder and subsequent chlorination with sodium hypochlorite. Both PBTA-7 and PBTA-8 exerted strong mutagenicity in Salmonella typhimurium TA98 and YG1024 in the presence of S9 mix (43 000 and 1 430 000 revertants/nmol for PBTA-7 and 40 700 and 2 213 000 revertants/nmol for PBTA-8 in TA98 and YG1024). To clarify whether PBTA-7 and PBTA-8 exist in the environment, water samples were collected at seven sites in six rivers flowing through two different regions where textile dyeing industries are located. All water samples were mutagenic in Salmonella typhimurium YG1024 with S9 mix and their potencies ranged from 108 000 to 1 990 000 revertants/g blue rayon. PBTA-7 and PBTA-8 were detected in water samples from both regions at levels of <0.1-101.4 ng/g blue rayon and <0.1-48.9 ng/g blue rayon, respectively. In some samples PBTA-7 and PBTA-8 could contribute up to 15% of the water mutagenicity.     

Immunological comparison of glycopeptides obtained from haptoglobin types 1-1, 2-1 and 2-2

Immunochemical properties of glycopeptides III and IV obtained from haptoglobin (Hp) types 1-1, 2-1, and 2-2, by trypsin digestion were studied by double immunodiffusion test, quantitative precipitation and crossed immunoelectrophoresis with antisera directed against Hp 1-1, Hp 2-1, and Hp 2-2, respectively. Trypsin digestion resulted in an exposition in the glycopeptide IV 1-1 of the antigenic determinant characteristic of Hp 1-1, which had been hidden inside the molecule of the native Hp 1-1. On the contrary, it was not possible to find an antigenic determinant characteristic of the product of alpha 2 gene.     

Polymer synthesis based on 2-(hydroxyphenyl)-2-oxazolines

2-(Hydroxyphenyl)-2oxazolines(p- and n-isomers 1a and 1b ) were used for the synthesis of various polymers. Cationic polymerization of 2-methyl-2-oxazoline initiated with the N-methyl 2 -oxazolinium species 3 , Derived from 1 , Gave telechelic poly(N-acetylethylenimine) ( 5 ) having a hydroxyl group of different reactivity at both ends. Anionic polymerization of ethylene oxide induced by the lithium salt of 1, 7 , produced a poly(ethylene oxide) macromer, 9 , having a ringopening polymerizable 2-oxazoline group. The copolymer from 9 and 2-phenyl-2oxazoline, 10 , has been shown to have good properties as a nonionic polymeric surfactant in which the N-benzoylethylenimine main-chain behaves as a lipophilic group whereas the oxyethylene graftchains act as a hydrophilic group. Di-salt 11 derived from 1 was polymerized to give polymide 13 (“amphi-ionic polymerization”).