石墨炉-原子吸收光谱法测定僵蚕中铅、镉含量

目的:利用石墨炉-原子吸收光谱法测定僵蚕中铅和镉两种重金属元素含量.方法:收集6种不同来源的僵蚕药材,采用浓硝酸-高氯酸(4:1)混合溶液湿法消解样品,用石墨炉-原子吸收光谱法测定僵蚕的铅和镉含量.结果:铅和镉的质量浓度分别在40μg·L-1和7.2 μg·L-1以内与吸光度相关性良好,其检出限(3 s)分别为1.02μg·L-1和0.10 μg·L-1;6种僵蚕样品铅含量均小于5.0 mg·kg-1,镉含量均小于0.3 mg·kg-1;用标准加入法测得铅和镉回收率依次为99.5％,103.5％,相对标准偏差(n=6)均小于5.0％.结论:该方法快速、灵敏、准确,稳定性好,可用于僵蚕药材中铅和镉含量测定.     

七种中成药中有毒重金属元素的测定

目的建立原子吸收分光光度法测定灯盏花素注射液、丹参注射液、清开灵注射液、胃康灵胶囊、冠心丹参胶囊、康尔心胶囊和桂龙咳喘宁胶囊中砷、汞、铅、镉的残留量。方法湿法消解样品,运用氢化物发生原子吸收分光光度法测定砷、汞和铅的含量,用空气-乙炔火焰原子吸收分光光度法测定镉的含量。结果在丹参注射液和康尔心胶囊中,砷的回收率分别为89.01%~116.41%和93.60%~103.17%,汞的回收率分别为80.70%~113.83%和86.12%~115.88%,铅的回收率分别为96.27%~109.48%和99.97%~110.61%,镉的回收率分别为93.00%~114.40%和96.50%~102.93%。结论7种中成药中砷、汞、铅、镉的残留量均不超标。     

东莨菪碱对动脉平滑肌细胞的作用

以培养的兔ASMC为材料,研究了Scop对细胞增殖的影响。有Ca~(2 )时,Scop抑制ASMC的增殖;缺Ca~(2 )时则表现为双向作用,即低浓度刺激、高浓度抑制ASMC增殖。培养液中有Cd~(2 )存在时,Scop对ASMC增殖仍表现为双向作用。     

113Cd Nuclear Magnetic Resonance (NMR) Study of the Inhibitory Effect of Methylvinylether/Maleic Acid (PVM/MA) Copolymer on the Alkaline Phosphatase of Escherichia coli

The inhibitory effect of PVM/MA copolymer on the alkaline phosphatase (AP) of E. coli was investigated. Kinetic studies indicated that enzyme inhibition was characterized by a reduction in both the Vmax and the Km. Addition of 1 mM zinc or magnesium ions to the reaction prevented inhibition of the enzyme by the copolymer. The inhibitory effect of the copolymer on alkaline phosphatase was also investigated using 113Cd NMR after exchange of the active center metal ions with 113Cd. The resulting Cd(II)6AP exhibited characteristic 113Cd resonances reflecting the environment of the A, B, and C metal binding sites of the enzyme's active center. Addition of copolymer resulted in a 113Cd NMR spectrum which indicated removal of 113Cd from the C site and formation of two distinct forms of the enzyme. Possible explanations for the 113Cd NMR results are discussed.     

饲料添加剂氧化锌的研制与生产

对利用化学工业保险粉副产品生产饲料级氧化锌的工艺以及参数进行了研究，探讨了降低重金属Ｐｂ和Ｃｄ含量、提高饲料级氧化锌纯度的有效途径，研究结果表明：控制生产保险粉、雕白块的原料锌或锌锭的质量，采用马弗炉焙烧工艺，饲料级氧化锌的主含量达到了９８．３％，产品中铅的含量为７×１０－６，镉的含量为７×１０－６。制定了中华人民共和国饲料添加剂氧化锌的行业标准。     

镉中毒肾损害大鼠尿中不同分子量镉,锌结合物的研究

研究结果表明,肾功能受损以前,尿镉仅以小分子结合镉的形式排泄;当肾镉负荷超过其临界浓度并引起肾功能障碍后,尿镉排泄急剧增加,其绝大多数以金属硫蛋白结合镉的形式排泄,同时小分子结合镉也继续增多;随着肾损害的加重,尿中又相继出现中、高分子蛋白质结合镉。但是,尿金属硫蛋白结合镉是肾脏受损后尿镉的主要形式。正常动物尿锌主要以小分子结合锌形式存在,镉性肾损害严重时方有尿锌显著升高,且主要系高分子结合锌排泄增多。     

Square-wave stripping voltammetry for direct determination of eight heavy metals in soil and indoor-airborne particulate matter

The application of square-wave voltammetry (SWV) for the determination of eight elements viz. Cd(II), Pb(II), Cu(II), Zn(II), Co(II), Ni(II), Cr(VI), and Mo(VI) in soil and indoor-airborne particulate matter has been examined and optimized. The cathodic and anodic types of the SWV technique were examined for the detection of these metal ions. It was found that the square-wave anodic stripping voltammetry is the conventional technique for the determination of Zn(II), Cd(II), Pb(II), and Cu(II), but square-wave adsorptive cathodic stripping voltammetric method is used for the determination of Co(II), Ni(II), Mo(VI) and Cr(VI). Various experimental parameters, which influenced the response of the mercury film electrode to these metal ions, were optimized. The detection limits of these metal ions were 0.03, 0.4, 0.04, 0.1, 0.15, 0.05, 0.2, and 3.2 microg/kg for Cd(II), Pb(II), Cu(II), Zn(II), Co(II), Ni(II), Cr(VI), and Mo(VI), respectively, with very good accuracy (standard deviation is below 2%). Interference from coexisting ions was successfully investigated. A comparison of analytical data for analyzing real samples was carried out between the SWV method and the graphite furnace atomic absorption spectrophotometric (GFAAS) method. By the standard addition method, the recoveries were 96.6-104% with SD of 0.75-2.5%. The great advantage of SWV is the simplicity, selectivity, sensitivity, and shortening analysis time over the GFAAS method.     

Analysis of cytotoxicities of platinum compounds

Extent of DNA platination, loss of cell viability, DNA fragmentation, and impairment of cellular mitochondrial oxygen consumption are measures of drug cytotoxicity. We measured and compared these effects for cisplatin, oxaliplatin and carboplatin. Because reaction with intracellular thiols may be responsible for drug resistance, we also determined the rates of Pt drug reactions with metallothionein. Jurkat cells were exposed at 37°C to 25 μM Pt drugs for 3 h. Pt-DNA adducts were determined at the end of the incubation period by atomic absorption spectroscopy. Viability, DNA fragmentation, and cellular respiration (μM O₂/min/10⁶ cells) were determined 24 h post drug exposure. The average amount of Pt-DNA adducts (Pt atoms/10⁶ nucleotides) produced by cisplatin was 43.4, by oxaliplatin 4.8 and by carboplatin 1.5. Cisplatin decreased the rate of respiration by ~63% and oxaliplatin by ~37%. DNA fragmentation by cisplatin and oxaliplatin was very similar. Carboplatin produced an unnoticeable effect on cellular respiration, and only ~10% of the DNA fragmentation was produced by cisplatin or oxaliplatin. Although, for a given drug, all four measures of cytotoxicity were proportional, this did not hold for comparisons between the drugs. The rate constants (M⁻¹ s⁻¹) for reaction of cisplatin, oxaliplatin and carboplatin with Cd/Zn thionein were 0.75, 0.44 and 0.012, respectively. For comparison, the rate constants (M⁻¹ s⁻¹) for reaction of cisplatin, oxaliplatin and carboplatin with glutathione were 0.027, 0.038 and 0.0012, respectively. The low reactivity of carboplatin with metallothionein and glutathione suggests that its low cytotoxic activities are not due to reaction of Pt²⁺ with cellular thiols. Despite a tenfold difference in Pt-DNA adducts between cisplatin and oxaliplatin, the cytotoxicities of these compounds are very similar, suggesting that oxaliplatin lesions are more potent than cisplatin lesions. The results demonstrate a large influence of the ligands occupying Pt coordination spheres on the chemical and biologic activities of Pt drugs. This work was supported by a generous fund from the Paige’s Butterfly Run.     

Role of Everolimus on Cardiac Functions in Kidney Transplant Recipients

Background

Kidney transplantation is known to increase the survival of dialysis patients by ameloriating cardiac status, including both systolic and diastolic functions. We aimed to evaluate the role of immunosuppressive drug regimens on cardiac functions of kidney transplant recipients (KTRs).