Radioisotope assessment of heart damage in hypertransfused thalassaemic patients

Twenty-five thalassaemic patients treated with repeated blood transfusion (BT) and intensive iron removal therapy were studied by echocardiography and rest/stress equilibrium gated radionuclide angiocardiography (EGNA). Stress left ventricular ejection fraction (LVEF) showed an important negative correlation with number of BTs (r = –0.75). Abnormal values of stress LVEF were measured after 200 BTs: these data demonstrate the effectiveness of stress LVEF in the follow-up of patients who have undergone repeated BTs and the clinical importance of intensive chelation therapy. Peak filling rate did not show diagnostic value in the early detection of iron cardiotoxicity. However, its inverse correlation with BT (r = –60) indicates that iron overload depresses the diastolic parameters.     

Effects of 4-aminopyridine on the turnover of monoamines in the central nervous system of the rat

Summary The effects of 4-aminopyridine (4-AP) on the turnovers of 5-hydroxytryptamine, dopamine and noradrenaline in the central nervous system of rats were studied by means of amine disappearance following inhibition of tryptophan or tyrosine hydroxylase. 4-AP (3 mg/kg i.p.) did not change the utilizations of 5-hydroxytryptamine or dopamine but it markedly accelerated that of noradrenaline in the brain and in the spinal cord. This stimulatory effect of 4-AP was completely dependent on nerve impulses since no effect was observed following an acute section of the noradrenaline nerves to the spinal cord. The effect of 4-AP was blocked by the-adrenoreceptor stimulating agent clonidine. Pentylenetetrazole, at a dose producing similar behavioural changes as 4-AP, caused only a slight stimulation of the noradrenaline turnover. 4-AP might enhance the flux of calcium ions into nerve terminals during depolarization, and thus increase the release of noradrenaline, whereas this process might be of less importance in the dopamine and the 5-hydroxytryptamine nerves.     

Endogenous and exogenous nitric oxide enhance the DNA strand scission induced by tert-butylhydroperoxide in PC12 cells via peroxynitrite-dependent and independent mechanisms, respectively

A short-term exposure to tert-butylhydroperoxide (tB-OOH) promoted a concentration-dependent formation of DNA single-strand breaks in PC12 cells. These events were paralleled by an increase in the cytosolic concentration of Ca2+ that was in part cleared by the mitochondria. Unlike the extent of Ca2+ mobilization and/or mitochondrial Ca2+ clearance, the DNA strand scission evoked by the hydroperoxide was markedly reduced by the nitric oxide (NO) scavenger 2-phenyl-4,4,5,5-tetramethylimidazolin-1-oxyl-3-oxide (PTIO) or by the NO synthase inhibitor N-nitro-L-arginine methylester (L-NAME). Inhibitors of electron transport (rotenone and myxothiazol), ruthenium red (RR, a polycation which inhibits the calcium uniporter of mitochondria), or peroxynitrite scavengers (Trolox and L-methionine) were as effective as PTIO or L-NAME in inhibiting the DNA-damaging response mediated by tB-OOH. Rotenone, RR or peroxynitrite scavengers did not further reduce the residual DNA cleavage observed following treatment with tB-OOH in L-NAME-supplemented cells. Exogenous NO also increased the DNA damage caused by tB-OOH in L-NAME-supplemented cells and this response was blunted by RR or by inhibitors of electron transport but was insensitive to peroxynitrite scavengers. We conclude that both endogenous and exogenous NO enhance the DNA cleavage generated by tB-OOH in PC12 cells. However, only endogenous NO set the bases for an involvement of peroxynitrite in this DNA-damaging response.     

Metal ions and human sperm mannose receptors

Zinc and lead concentrations were measured in seminal plasma from fertile donors, infertile men with varicocoele and men undergoing work-ups for in vitro fertilization. Ejaculated spermatozoa from these subjects were incubated in vitro with various metal ions and/or dibromoethane and dibromochloropropane. Mannose receptor expression was correlated with metal and toxicant levels. Sperm distributions of potassium channels were compared with lead ions and calcium channels with zinc ions. Mannose receptor expression by capacitated spermatozoa increased linearly with seminal plasma zinc levels, and correlated inversely with lead levels. Cobalt had no effect on mannose receptor expression, but nickel had a concentration-dependent biphasic effect. Mannose receptor expression was not affected by dibromoethane and dibromochloropropane if the cholesterol content of the sperm membrane was high, but mannose receptor expression was decreased in low cholesterol spermatozoa by exposures below estimated permissive exposure limits. Potassium channels and lead ions co-localized over the entire head of human spermatozoa, while both calcium channels and zinc ions were confined to the equatorial segment of the head. Mannose receptor expression on the external surface of the human sperm plasma membrane is a biomarker for the effects of transition and heavy metals and organic toxicants on sperm fertility potential.     

环丙沙星荧光特性的研究

目的:建立荧光测定环丙沙星含量的方法,对几种金属离子(Fe~(3+),Cu~(2+),Zn~(2+))与环丙沙星的络合反应及其对荧光特性的影响作初步的研究。方法:用日立荧光分光光度计测定,测量波长λ_(ex)=277 nm,λ_(em)=450nm。测定时的最佳pH为2.2。结果:环丙沙星浓度在0.1～0.8mg·L~(-1)范围内与荧光强度呈线性关系,相关系数为0.9999,检测限为4.5×10~(-3) mg·L~(-1)。结论:该法方便、快速,可用于直接测定环丙沙星含量,或用于微量分析。     

铁补充对大鼠肝脏铁与叶酸代谢的影响

目的研究缺铁性贫血时机体内叶酸含量的变化及其与铁补充的关系。方法ＳＤ纯品系雄性断乳大鼠３２只，随机分为铁正常、铁缺乏两组。喂纯合成饲料，铁含量分别为８００μｇ与小于２０μｇ，每日两次定时喂饲。两组模型建立后再各取一半大鼠每日补充铁剂８０００μｇ，同前方式每日两次喂饲；另一半大鼠继续原方案不变，共建立铁正常补铁组、铁缺乏补铁组与铁正常、铁缺乏对照４个组；４个实验组每日饲料叶酸含量均小于１０μｇ。结果铁缺乏影响大鼠的一般生长，体重与血红蛋白含量；肝脏重量与肝内铁含量明显低于正常水平，而叶酸含量明显高于铁正常大鼠。补铁后，铁缺乏大鼠的生长、体重、血红蛋白以及肝脏重量明显改善，肝脏的铁含量迅速增加并超出正常水平。在肝脏铁增加的同时，肝脏组织的叶酸含量明显下降，直至显著低于正常。结论提示铁与叶酸同时缺乏的大鼠在补充大剂量铁剂后导致机体内叶酸含量进一步减少，而铁正常大鼠上述变化不明显。     

电喷雾离子化多级质谱对几种氨基糖苷类抗生素特征碎片的分析

应用电喷雾离子化多级质谱法分析几种含2-脱氧链霉胺的氨基糖苷类抗生索的碎片离子，并对它们的裂解规律进行分析归纳。除其它特征碎片离子峰外，所有测试样品的质谱图中都存在质荷比为163．1的归属于2-脱氧链霉胺的碎片离子峰。这些裂解规律可应用于微生物新药筛选中早期快速鉴别含2-脱氧链霉胺的氩基糖苷类抗生索，对氨基糖苷类抗生索的生产、质量监控以及在环境和食品中的微量检测也有指导意义。     

孕妇不同时期补充锌铁对胎儿生长发育影响的研究

目的　探讨孕妇不同时期补充锌铁对胎儿生长和发育的影响。　方法　对 198名孕妇补充锌铁后测定其胎儿生长发育指标。　结果　除晚妊组外 ,初、中妊组胎儿其生长发育指标明显优于对照组 ,呈显著性差异 (P <0 .0 5 )。　结论　补充锌铁对胎儿生长发育有着积极的意义 ;补充越早 ,效果越好     

北京、西安市居民对铁缺乏和铁强化酱油知识和态度的定性研究

目的　调查北京、西安市居民对铁缺乏和铁强化酱油的知识和态度。方法　以专题小组讨论法 ,对北京的 2 6名孕妇、 2 7名学生家长、 2 9名社区居民及西安的 13名孕妇、 14名社区居民进行调查 ;他们的年龄在 2 0～ 6 5岁间 ,大部分接受过中等及以上的教育。结果　这两所城市的大部分被访对象具有一些营养知识。人们对钙缺乏的了解多于对铁缺乏的了解。较药物补充 ,人们更愿意通过食物来补充铁的摄入。多数人接受强化食品 ,北京的大部分被访者更愿意购买瓶装的酱油 ,并表达出愿意试用铁强化酱油 ,但一些人担心铁强化酱油的效果、安全性、质量、价格及口感。很多西安的孕妇由于听说“吃酱油会导致面部色素沉着”而在孕期不吃酱油。大部分西安居民愿意购买便宜的散装酱油。结论　北京市与西安市的居民在铁强化食品的态度上存在一定的差别。关于铁的营养及铁缺乏的知识宣传很是不够     

纳米铁、纳米氧化锌和纳米氧化镁对小鼠血清乳酸脱氢酶和α-羟丁酸脱氢酶活性的影响

目的探讨纳米铁(Fe)、纳米氧化锌(ZnO)和纳米氧化镁(MgO)材料对小鼠血清乳酸脱氢酶(LDH)和α-羟丁酸脱氢酶(α-HBDH)活力的影响。方法分别以5g/Kg·wt剂量的纳米(Nano-)或微米(Micro-)粒径Fe、ZnO和MgO给小鼠一次经口灌胃,14d后处死取血分离血清分析LDH和α-HBDH活性变化。结果Nano-和Micro-Fe染毒小鼠血清LDH活力均比对照组明显降低(P<0.05),但Nano-Fe和Micro-Fe组小鼠血清LDH差异无显著性(P>0.05);对照、Nano-Fe和Micro-Fe三组小鼠血清α-HBDH差异无显著性(P>0.05)。Nano-MgO组小鼠血清LDH比对照组有所升高,但差异无显著性(P>0.05)。Micro-MgO组小鼠血清LDH比对照组和Nano-MgO组有明显升高(P<0.05);对照、Nano-MgO和Micro-MgO三组小鼠血清α-HBDH差异则无显著性(P>0.05)。两种粒径ZnO染毒组小鼠血清LDH和α-HBDH比对照组有显著性升高(P<0.05),其中Micro-ZnO组小鼠血清LDH和α-HBDH活力升高的更为显著(P>0.05)。结论Nano-Fe、Nano-ZnO和Nano-MgO材料对小鼠血清LDH及α-HBDH活性的影响与相应微米粒径材料有所不同。