银诱导大鼠肝脏金属硫蛋白的提纯与鉴定

Ｗｉｓｔａｒ公鼠经腹腔注射ＡｇＮＯ３后可诱导肝脏合成ＭＴ。经匀浆、乙醇沉降、Ｓｅｐｈａｄｅｘ－７５、ＤＥＡＥ－５２两次柱层析，可得到两个亚型。原子吸收测定结果表明：该蛋白分别含７份Ａｇ、２份Ｚｎ和２份Ｃｕ，具有与Ｃｄ５Ｚｎ２－ＭＴ并不相同的二级、三级结构。进一步研究表明，蛋白中伴随Ｃｕ和Ｚｎ的含量与所用诱发剂的种类、数量均有关，且Ｃｕ和Ｚｎ（通过ＭＴ）具有某种微妙的联系。     

Zn、Mg、FT3、FT4在甲亢患者血清中的含量及相关性探讨

测定了３１例甲状腺机能亢进患者血清中Ｚｎ,Ｍｇ和Ｔ３,Ｔ４含量,并对其临床意义及相关性进行了探讨,同时作正常人对照,经统计学处理。结果表明：Ｍｇ明显降低（Ｐ〈０．０１）,Ｚｎ明显升高（Ｐ〈０．０１）,ＦＴ３,ＦＴ４明显升高（Ｐ〈０．０５）,但此两种元素含量与ＰＴ３,ＰＴ４水平没有等级相关性。     

兔金属硫蛋白的分离与纯化

兔皮下注射ＣｄＣｌ２诱导金属硫蛋白（Ｍｅｔａｌｌｏｔｈｉｏｎｅｉｎ，简称ＭＴ），取肝脏匀浆，用乙醇─氯仿混合液萃取后经ＳｅｐｈｄｅｘＧ－５０柱分离，得到混合型ＭＴ．进一步用纤维素弱碱性阴离子交换树脂进行拆分，并在ＳｅｐｈａｄｅｘＧ－２５柱上脱盐，得到ＭＴ－１和ＭＴ－２两种亚型．经氨基酸组咸、凝胶电泳及ＨＰＬＣ柱层析等分析表明，所得的两种亚型具有高度的均一性．     

氧化物-NaZSM-5催化剂的研究Ⅱ.ZnO-NaZSM-5的催化性能

研究了不同ＺｎＯ负载量的ＺｎＯ－ＮａＺＳＭ－５催化剂对甲醇、乙醇和正丙胺转化反应的催化行为，与ＮａＺＳＭ－５和ＺｎＯ相比，ＺｎＯ－ＮａＺＳＭ－５系列催化剂具有更高的催化活性和独特的产物选择性，ＺｎＯ高度分散的样品在甲醇、乙醇和正丙胺转化反应中表现出更有效的酸－碱双功能催化作用，还讨论了酸－碱对中心ＺｎＯ在这些催化反应中的作用。     

电化学聚合漆酚-锌金属螯合物合成及性质研究

以电化学方法合成了聚合漆酚（ＥＰＵ）,并用ＥＰＵ与二异丙氧基锌作用生成漆酚金属螯合物「ＥＰＵ－Ｚｎ（Ⅱ）」,采用原子发射光谱（ＡＥＳ）、ＦＴ－ＩＲ、ＤＭＴＡ、ＴＧ－ＤＴＡ和ＸＰＳ等对其进行表征,探讨其结构与性质。证明了螯合物中存在着因Ｚｎ（Ⅱ）和ＥＰＵ配位作用而引起的交联,故难溶于绝大多数的有机溶剂,玻璃化转变温度和耐热性能的提高。     

金属卟啉－甲基紫精二连体配合物的合成及其光化学行为

本文合成了四（对－氯代甲基）苯基－甲基紫精卟啉及其Ｚｎ，Ｃｏ，Ｍｎ配合物，用元素分析、红外光谱和紫外可见光谱进行了表征。研究了它们的光化学性质。结果表明，在ＴＥＯＡ中光照使Ｍ。ＴＣＭＰＰ－ｍｖ＾２＋发生了分子内从卟啉到甲基紫精的电子迁移反应。在ＺｎＴＣＭＰＰ－ｍｖ＾２＋／ＴＥＯＡ／ＤＭＳＯ－Ｈ２Ｏ体系中可发生光敏化还原ｍｖ＾２＋反应，生成较稳定的ｍｖ＾＋。在Ｍｎ（Ⅲ）ＴＣＭＰＰ－ＭＶ＾２＋／ＣＨ３     

氧化物－NaZSM－5催化剂的研究 Ⅱ．ZnO－NaZSM－5的催化性能

研究了不同ＺｎＯ负载量的ＺｎＯ－ＮａＺＳＭ－５催化剂对甲醇、乙醇和王丙胺转化反应的催化行为．与ＮａＺＳＭ－５和ＺｎＯ相比，ＺｎＯ－ＮａＺＳＭ－５系列催化剂具有更高的催化活性和独特的产物选择性．ＺｎＯ高度分散的样品在甲醇、乙醇和正丙胺转化反应中表现出更有效的酸－碱双功能催化作用．还讨论了酸－碱对中心Ｚｎ－Ｏ在这些催化反应中的作用．     

金属硫蛋白与Cd2+、Pb2+络合反应的微量量热滴定

金属硫蛋白（ｍｅｔａｌｌｏｔｈｉｏｎｅｉｎ,简称ＭＴ）是一类低分子量、富含半胱氨酸的金属结合蛋白,具有调节体内微量金属元素（Ｚｎ、Ｃｕ等）代谢、重金属解毒和清除自由基等多种生物学功能［１］．ＭＴ与金属离子的络合作用是发挥其功能的物质基础,哺乳动物ＭＴ每分子含２０个半胱氨酸巯基,可结合７个二价金属离子或１２个一价金属离子;通常,各种金属离子的结合能力与典型的硫酸盐型络合物的顺序一致,即 Ｚｎ（Ⅱ）＜ Ｐｂ（Ⅱ）＜ Ｃｄ（Ⅱ）＜ Ｃｕ（Ⅰ）, Ｈｇ（Ⅰ）, Ｈｇ（Ⅱ）, Ｂｉ（Ⅲ）［２］．哺乳动物Ｃｄ７－…     

聚苯胺对2,5—二巯基—1,3,4—噻二唑氧化还原反应的电化学？…

研究了聚苯胺（ＰＡn）膜电极在２,５－二巯基－１,３,４－噻二唑（ＤＭcＴ）溶液中电化学处理或浸泡后的循环伏安（ＣＶ）曲线的变化规律。实验结果表明,ＰＡn膜电极在 ＤＭcＴ溶液中进行电化学处理或浸泡过程可使ＤＭcＴ进入ＰＡn膜内部与ＰＡn形成复合物。ＰＡn对ＤＭcＴ的电化学催化作用可能和二者之间形成的电子给体－受体复合物有关。该复合物的电何尝氧化还原特性不同于ＰＡn对ＤＭcＴ的电化学催化作用可能和得之间形成的     

血液病与微量元素关系的研究

研究了血液病与微量元素的关系,发现再生障碍性贫血患者治疗前血清Ｃｕ升高（Ｐ〈０．０５）,缓解后Ｃｕ恢复正常。骨髓增生异常综合征（ＭＤＳ）中ＲＡ＋ＲＡＳ组Ｃｕ及Ｃｕ／Ｚｎ比值高,Ｚｎ值降低不明显;ＲＡＥＢ＋ＲＡＥＢ－Ｔ组Ｃｕ及Ｃｕ／Ｚｎ高,Ｚｎ值明显降低（Ｐ〈０．０５）。急性白血病、淋巴瘤、多发性骨髓瘤及慢粒患者血清Ｃｕ、Ｚｎ及Ｃｕ／Ｚｎ比值与对照组比较均呈显著差异（Ｐ〈０．０５￣０．０１）,而缓解     

Constant Current Stripping Chronopotentiometry for the Study of Adsorbing Inert and Electrochemically Nonreversible Metal Complexes at Low Concentrations: Application to Cd and Zn Metallothioneins

Constant current chronopotentiometric stripping analysis using adsorptive accumulation and negative stripping current (AdSCP) was applied for the study of behavior of rabbit liver Cd‐Zn and Zn metallothionein (Cd‐Zn‐MT, ZnMT) on hanging mercury drop electrode. Electrochemically inert or labile behavior of complexes can be distinguished with the application of high (1000 nA) or low (100 to 20 nA) current. Using high current, no influence of added Cd²⁺ or Zn²⁺ ions on the reduction of Cd(II) or Zn(II) complexed within MT molecule was observed, except of additions of Cd²⁺ to ZnMT, where bound Zn(II) was substituted by cadmium ions. With lowering of stripping current and increasing concentration of added Cd²⁺ or Zn²⁺ ions in solution progressive formation of reorganized complex with labile behavior is observed. Parallel measurement using DC voltammetry with different rates of polarization or differential pulse voltammetry were in agreement with AdSCP measurement. However, only chronopotentiometric method combines good sensitivity and signal separation at μM concentrations, inevitable in MT studies.     

Computational studies of the coordination stereochemistry, bonding, and metal selectivity of mercury

Knowledge of the bonding and selectivity of organic mercury, [H3C-Hg]+ (MeHg+), and inorganic Hg2+ for protein and DNA functional groups is important for understanding the mechanism of heavy metal poisoning. Herein, we elucidate (1) the differences between inorganic Hg2+ and organic MeHg+ in their interactions with different ligands of biological interest, (2) the protein and DNA functional groups that Hg2+ and MeHg+ target in aqueous solution, and (3) the likelihood of "soft" Hg2+ displacing the "borderline" Zn2+ bound to "harder" nitrogen/oxygen-containing side chains such as His and Asp/Glu. The results reveal that, relative to Hg2+, the lower positive charge on MeHg+ results in a longer and weaker bond with a given ligand, in accord with the observed kinetic lability of MeHg+ complexes. They also indicate that negatively charged or polar amino acid side chains containing S-/O-/S/N donors could coordinate to both organic MeHg+ and inorganic Hg2+. In addition, Gua and Cyt could also coordinate to MeHg+ and disrupt Gua...Cyt base pairing. A key novel finding is that Hg2+ is a far better electron acceptor than Zn2+, and can thus accept more negative charge from the Zn ligands than the native Zn2+, thus enhancing Hg-ligand interactions and enabling Hg2+ to displace the native cofactor from zinc essential enzymes and "structural" Zn proteins. The results herein support several possible mechanisms for Hg poisoning. Ways that mercury poisoning could be prevented in cells are discussed.     

Uptake and effect of mercury on amino acid losses from the gills of the bivalve mollusks Mytilus californianus and Anodonta californiensis

Inorganic mercury (Hg(2+)) and herbicides are important contaminants of world water systems with effects on aquatic organisms and humans. The uptake of Hg(2+) and glycine by the gills of the bivalve mollusks Mytilus californianus and Anodonta californiensis was determined. Additionally, the effects of glycine, 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4-dinitrophenol (DNP) on the uptake of Hg(2+) were also determined. The loss of primary amines from the excised gills of both species was measured in the presence and absence of Hg(2+) or MeHg(+). The results indicate that (1) the uptake of Hg(2+) is approximately equivalent in both species; (2) comparison of the uptakes with that of inulin, which occupies only extracellular space, shows that Hg(2+) is taken up; (3) the uptake of Hg(2+) is slightly altered by the presence of glycine and herbicides such as 2,4-D and DNP; (4) the rate of loss of primary amines was highly increased relative to the control by the presence of Hg(2+) and to a lesser extent MeHg(+) for both species. These results showed that both inorganic and MeHg(+) are effective in disrupting the permeability of cell membranes, causing leakage of essential amino acids from the cell. This could result in discharge of potential gradients, reduced efficiency of energy coupling, and consequently cell death.     

FAILURE OF UVR DOSE RECIPROCITY FOR SKIN TUMORIGENESIS IN HAIRLESS MICE TREATED WITH 8-METHOXYPSORALEN

Abstract— 8-Methoxypsoralen (8-MOP) phototumorigenesis was studied in hairless albino mice irradiated with solar simulated radiation (SSR). Animals were exposed to three different daily doses of SSR after application of an oily vehicle with or without 8-MOP. Tumor production was dependent on daily SSR dose irrespective of topical treatment. The phototumorigenic potency of SSR was increased by the vehicle and to a much greater extent by inclusion of 8-MOP. Irrespective of topical treatment, a failure in dose reciprocity for tumorigenesis was demonstrated; in terms of cumulative SSR dose, the lower daily doses were more tumorigenic than the higher doses. This reciprocity failure in 8-MOP photosensitized mice is similar to that previously observed for UV-B phototumorigenesis. The relevance of these findings to therapeutic use of psoralens is discussed.     

二氯苯染毒对小鼠组织中Zn、Cu、Fe含量的影响

采用亚急性试验,探讨对二氯苯（P—DCB）对小鼠组织中Zn、Cu、Fe的影响。选用36只小鼠,雌雄各半,随机分成3组,每组12只,分别给予P—DCBO（对照组）、450、900mg·kg^-1,每天灌胃染毒1次,连续7d,染毒结束后24h处死动物并称体质量、肝、肾质量,计算脏器系数。用火焰原子吸收法测定肝脏、血液和肾脏中Zn、Cu、Fe含量。与对照组相比,各染毒组体质量无明显变化。各组肝体系数无差异,但染毒组肾体系数明显高于对照组（P〈O．05）。900mg·kg^-1组肝脏中Zn含量及w（Zn）／w（Cu）值较450mg·kg^-1组有明显升高。与对照组相比,各染毒组血液中Zn含量呈现下降趋势,900nag·kg^-1组较对照组明显下降（P〈0．05）。900mg·kg^-1组肾脏中Cu质量分数明显低于450mg·kg^-1组,Fe质量分数则较对照组及450mg·kg^-1组均有降低,P—DCB可影响小鼠组织中元素Zn、Cu、Fe的含量及不同器官的再分布,提示微量元素失衡可能是P—DCB毒作用的重要机制。     

Comparative study of effect of low and medium dose rate of γ irradiation on microporous polysulfone membrane using spectroscopic and imaging techniques

The effect of low (LDR) and medium dose rate (MDR) of γ irradiation at low doses (0-100 kGy) on the structural and chemical changes of microporous polysulfone (PSf) membrane has been studied using UV-vis, FTIR, SEM and dead-end filtration techniques. PSf membrane was cast by phase inversion method. Irradiation was done at room temperature in air media. The doses chosen were 0-100 kGy for LDR and 0-50 kGy for MDR; they were below and above sterilization dose. Analysis of UV-vis and IR spectra and SEM images obtained suggested that chain scissions and crosslink had occurred simultaneously in the irradiated membranes in both cases. This radio-oxidation effects observed start at a very low dose i.e. 1.66 kGy and increase with increase in dose. It is supported by the flux values obtained; it is increased with increase in dose. The results indicate that a very low dose γ irradiation was able to change the physicochemical characteristics of microporous PSf membrane which depend on dose rate of exposure.     

Novel Ba_(0.5)Sr_(0.5)Fe_(0.8)Zn_(0.2)O_(3-δ) membranes for POM

A novel cobalt-free perovskite based on Ba_(0.5)Sr_(0.5)Fe_(0.8)Zn_(0.2)O_(3-δ)(BSFZ)were prepared by EDTA-citric acid method.The lattice constants of the BSFZ perovskite were characterized by in situ high-temperature X-ray diffraction(HTXRD).The thermal expansion coefficient of BSFZ is 10.5×10~(-6)K~(-1),which is lower than that of cobalt-based perovskite materials.The BSFZ membrane was also used to construct reactors for the partial oxidation of methane(POM)to syngas.Results show that the BSFZ membrane...     

Electron beam crosslinking of non-lead PVC formulations

PVC samples with lead-free and lead-base stabilizer, containing TMPTMA (trimethylolpropane trimethacrylate) as a crosslinker and DOP (2-ethylhexyl phthalate) as a plasticizer, were electron beam treated at different doses (2–200 kGy) and characterized to evaluate crosslinking and other several properties, as a continuation of our previously reported paper, where these PVC formulations, typical for wire and cable applications, underwent gamma irradiation. The PVC was formulated with two different stabilizing systems: Ca/Zn and dibasic lead phthalate for comparison, to use them as jackets for a 22 wire gage (AWG). Small samples of the jacketed wires were irradiated in an industrial Dynamitron electron accelerator for the corresponding doses, along with two dosimetric systems: radiochromic thin film and alanine pellets dosimeters. The maximum dose applied was decided as the crosslinking increased, until the gel content was stable. The dose of 200 kGy was the condition for the highest crosslinking, so most of the wire was irradiated at such dose. Chemical and mechanical evaluations were carried out to the irradiated wire. The results show that 200 kGy was too high dose for the materials, since an important degradation is observed for the Ca/Zn systems. Unfortunately, such dose affects basically to CaZn formulations, which showed much poorer performance than classical lead-containing compositions. The results also indicate that gel content is not the best way of deciding the optimum condition for irradiation.     

A Zinc(II)/poly(gamma-glutamic acid) complex as an oral therapeutic for the treatment of type-2 diabetic KKAy mice

In developing new insulin-mimetic zinc(II) complexes with various ligands including a biodegradable polymer, we prepared and characterized a Zn(gamma-pga) complex in solution as well as in solid, and investigated its in vitro insulin-mimetic activity and in vivo antidiabetic effect in type-2 diabetic KKA(y) mice. The in vitro insulin-mimetic activity of the Zn(gamma-pga) complex was considerable better than that of ZnSO(4). The Zn(gamma-pga) complex normalized the hyperglycemia in KKA(y) mice within 21 d when administrated orally at doses of 10-20 mg (0.15-0.31 mmol) Zn per kg body mass for 30 d. In addition, the impaired glucose tolerance, elevated HbA(1c) levels and metabolic syndromes were significantly improved in Zn(gamma-pga)-treated KKA(y) mice relative to those administrated with saline and ZnSO(4).     

Mercury speciation and total trace element determination of low-biomass biological samples

Current approaches to mercury speciation and total trace element analysis require separate extraction/digestions of the sample. Ecologically important aquatic organisms--notably primary consumers such as zooplankton, polychaetes and amphipods--usually yield very low biomass for analysis, even with significant compositing of multiple organisms. Individual organisms in the lower aquatic food chains (mussels, snails, oysters, silversides, killifish) can also have very low sample mass, and analysis of whole single organisms is important to metal uptake studies. A method for the determination of both methyl Hg and total heavy metal concentrations (Zn, As, Se, Cd, Hg, Pb) in a single, low-mass sample of aquatic organisms was developed. Samples (2 to 50 mg) were spiked with enriched with (201)MeHg and (199)Hg, then leached in 4 M HNO(3) at 55 degrees C for extraction of MeHg. After 16 h, an aliquot (0.05 mL) was removed to determine mercury species (methyl and inorganic Hg) by isotope dilution gas chromatography inductively coupled plasma mass spectrometry (ICP-MS). The leachate was then acidified to 9 M HNO(3) and digested in a microwave at 150 degrees C for 10 min, and total metal concentrations were determined by collision cell ICP-MS. The method was validated by analyzing five biological certified reference materials. Average percent recoveries for Zn, As, Se, Cd, MeHg, Hg(total) and Pb were 99.9%, 103.5%, 100.4%, 103.3%, 101%, 97.7%, and 97.1%, respectively. The correlation between the sum of MeHg and inorganic Hg from the speciation analysis and total Hg by conventional digestion of the sample was determined for a large sample set of aquatic invertebrates (n = 285). Excellent agreement between the two measured values was achieved. This method is advantageous in situations where sample size is limited, and where correlations between Hg species and other metals are required in the same sample. The method also provides further validation of speciation data, by corroborating the sum of the Hg species concentrations with the total Hg concentration.