氯化血红素作为过氧化物模拟酶催化测定雨水中过氧化氢

研究了Hemin作为过氧化物模拟酶对过氧化氢(H2O2)-4氨基安替比林(4-Aminoantipyrine,4-AAP)-对氯苯酚(p-Chlorophenol,p-CP)显色反应的催化特性及反应条件,该体系在pH9.5的条件下形成的酶催化产物在505nm处有最大的吸收,测定H2O2的表观摩尔吸光系数为2.9×103L·mol-1·cm-1。该方法简便,灵敏度和选择性较好,用于雨水中微量过氧化氢的直接测定,结果满意。     

氯高铁血红素胶囊溶出度测定方法的研究

目的研究氯高铁血红素溶出度测定方法。方法考察不同pH缓冲液和十二烷基硫酸钠对氯高铁血红素溶解速度的影响;建立了UV法测定氯高铁血红素的方法。结果通过实验,确定选用pH7.8缓冲液,并在其中加入5g·L-1的十二烷基硫酸钠作为溶出介质;建立了紫外法测定氯高铁血红素胶囊溶出度的方法,通过方法学考察,氯高铁血红素浓度在2~24mg·L-1范围内呈良好线性关系r=0.9999;辅料对吸收度无干扰,平均回收率为100.2%,RSD为0.61%;精密度、重现性均符合要求。结论说明所建立的方法简单可行,可以满足溶出度测定的需要。     

氯化血红素-空气催化氧化体系应用于利那洛肽的合成

目的 使用氯化血红素催化氧化的方法合成利那洛肽.方法 采用9-芴甲氧头羰基(Fmoc)固相合成策略,以Wang树脂为载体和三苯甲基(Trt)为保护基的半胱氨酸合成利那洛肽线性肽,使用氯化血红素-空气催化氧化体系一步氧化法构建3对二硫键,并与传统的空气、二甲基亚砜和碘(I2)氧化法进行了对比.结果和结论 相对于传统氧化法,氯化血红素催化氧化法可更快速、更高效地得到目标利那洛肽,为多肽合成中的二硫键形成提供一种新的方法.     

Modulation of heme oxygenase‐1 expression and activity affects streptozotocin‐induced diabetic nephropathy in rats

Heme oxygenase (HO)‐1 has exhibited nephro‐protective actions in different animal models; however, its full mechanistic potential in diabetic nephropathy (DN) has not yet been elucidated. Hence, the present study has been undertaken by inducing DN in rats using streptozotocin (50 mg/kg i.p.), with or without either HO‐1 inducer; hemin (HM; 40 μmol/kg, s.c.), or HO‐1 blocker; zinc protoporphyrin‐IX (ZnPP; 50 μmol/kg, i.p.), for one month. Compared to control, rats with DN suffered from hyperglycemia and hyperlipidemia, with signs of renal damage, as assessed by distortion in renal histopathologic architecture and kidney function. Renal oxidative/nitrosative stress was evident by increased malondialdehyde, nitric oxide, myeloperoxidase, with decreased reduced glutathione, superoxide dismutase, and catalase. DN group also exhibited high renal expression of the pro‐inflammatory cytokine; tumor necrosis factor (TNF)‐α, and the apoptotic marker; caspase 3, assessed by Western blot. Renal HO‐1 protein expression and activity were increased in DN rats compared to control. Administration of HM, but not ZnPP, to DN rats improved kidney function, histopathologic features, lipid profile, TNF‐α, and caspase 3 expressions, with no effect on blood glucose level. HM increased, while ZnPP decreased renal HO‐1 activity in DN rats. It is noteworthy that neither intervention affected HO‐1 activity or renal oxidative capacity in non‐diabetic rats. Interestingly, the expression of HO‐1 was upregulated by both HM and ZnPP in DN rats. In conclusion, activation of HO‐1 via HM ameliorated renal damage in STZ‐induced DN in rats, probably through antioxidant, anti‐nitrosative, anti‐inflammatory, and anti‐apoptotic mechanisms.     

蒿甲醚诱导日本血吸虫雌虫总抗氧化能力下降(英)

目的 观察蒿甲醚对日本血吸虫成虫总抗氧化能力的影响。 方法 体外将血吸虫在含蒿甲醚和氯化血红素的培养液内培养24 h后,或体内感染小鼠经蒿甲醚300mg/kg治疗6～24 h后,测定虫体的总抗氧化能力。 结果体外50μmol/L的蒿甲醚与氯化血红素伍用引起雌虫总抗氧化能力明显下降。体内蒿甲醚作用血吸虫6 h,即见雌虫的总抗氧化能力明显下降。体内、体外试验中,蒿甲醚对雄虫的总抗氧化能力均无影响。 结论 蒿甲醚诱导雌虫总抗氧化能力下降。     

Binding of hemin and Congo red by oral hemolytic spirochetes

Colony-forming units or cells in suspension of oral anaerobic spirochetes ( Treponema denticola, Treponema vincentii and Treponema socranskii ) bind hemin and Congo red. Hemin or Congo red binds to a hydrophobia polypeptide receptor that is located in the outer membrane of the bacterial cells and it has a relative molecular mass of 47 kDa. These oral spirochetes also lyse sheep erythrocytes to produce beta-hemolytic zones around colony-forming units. The oral spirochetes may acquire iron for growth when they lyse erythrocytes and bind heme from which they may sequester and transport iron into the cells.     

Hemin nutritional stress inhibits bacterial invasion of radicular dentine by two endodontic anaerobes

AIM: To determine if anaerobic bacteria routinely found in infected dentine and root canals require the presence of heme in the environment in order for them to invade dentinal tubules. METHODOLOGY: Noncarious, unrestored human teeth with single root canals were prepared for invasion experiments and soaked in either TSB-M supplemented with hemin (5 microg mL(-1)) (n = 12 roots), TSB-M media (n = 12 roots) or TSB-M media followed by hemin soak (n = 12 roots) for 2 days, then inoculated with either Prevotella intermedia ATCC 25611 or Peptostreptococcus micros ATCC 33270 and incubated anaerobically for 14 days. Roots were prepared for light microscopy, stained with Brown and Brenn or antisera raised to the bacteria, and invasion within tubules assessed using a tubule invasion index (TI). Data were analysed using Student's t-test and Mann-Whitney U-test. RESULTS: Prevotella intermedia (TI = 0.7 +/- 0.04) and P. micros (TI = 0.96 +/- 0.08) showed low invasion when grown in the presence of hemin with cells generally restricted to the superficial 20 microm of the tubules, whilst neither bacteria invaded tubules (TI = 0) when hemin was absent from the growth media (P < 0.01). CONCLUSIONS: Hemin was required in the growth medium for P. intermedia and P. micros to invade dentinal tubules.     

Regulation of transferrin receptors by iron in human erythroblasts

Previous reports of patients with persistent polyclonal B lymphocytosis have found associations with female sex, cigarette smoking, HLA-DR7 phenotype, and moderate elevation of peripheral blood polyclonal B lymphocytes. The presence of binucleated cells and atypical lymphocytes in the peripheral blood of these patients was highly suggestive of a viral infection, such as with the Epstein-Barr virus. We report a 47-year-old asymptomatic woman who was incidentally found to have persistent polyclonal B lymphocytosis and serum IgG against virus capsid antigen (VCA) and Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA) of EBV. The presence of EBV was investigated in the peripheral blood lymphocytes from this patient by in situ hybridization and polymerase chain reaction methods. EBV DNA was demonstrated in the lymphocyte fraction by polymerase chain reaction, and it was further located in lymphoid cells by in situ hybridization. These results indicate that persistent polyclonal B lymphocytosis is strongly associated with EBV.