Effects of central administration of lead, cadmium and other divalent cations on body temperature in mice

The intracerebroventricular administration of lead or cadmium to mice produced a marked decrease in body temperature. The maximum decreases in body temperature produced by the central administration of the heavy metals (1.97±0.3°C for lead and 2.87±0.6°C for cadmium) were similar to those obtained after acute peripheral administration of these compounds. The decreases in body temperature obtained after central administration of calcium, magnesium or zinc were significantly smaller than those produced by the heavy metals. The results indicate that the central nervous system is implicated in the hypothermia induced by these divalent cations and suggest that the alteration of membrane ionic permeability by these substances at hypothalamic sites may be related to the control of body temperature.     

兔肝金属硫蛋白结合铅离子的圆二色性光谱研究

从锌诱导的家兔肝脏中分离纯化得到金属硫蛋白两种亚型：ＺｎＭＴ－Ⅰ和ＺｎＭＴ－Ⅱ．在酸性条件下脱金属,经Ｓｅｐｈａｄｅｘ Ｇ－２５柱层析得到脱金属硫蛋白（ａｐｏＭＴｓ）．用圆二色性（ＣＤ）光谱法研究,发现两种亚型ａｐｏＭＴｓ 与Ｐｂ２＋ 的结合依赖于Ｐｂ２＋ 的加入比例及ｐＨ 值．ａｐｏＭＴ－Ⅰ在ｐＨ３～５之间,ａｐｏＭＴ－Ⅱ在ｐＨ４～６之间与Ｐｂ２＋ 结合形成特征簇合物Ｐｂ７ＭＴｓ,其ＣＤ谱图特征峰位于３１６ｎｍ （－ ）,２７０ ｎｍ （＋ ）,２４５ ｎｍ （＋ ）及２２５ ｎｍ （－ ）,提示解铅中毒的最佳条件应控制在弱酸性环境．不同亚型ａｐｏＭＴｓ 与Ｐｂ２＋ 的结合方式各不相同：Ｐｂ２＋ 与ａｐｏＭＴ－Ⅰ的结合采取平均分配的方式,而与ａｐｏＭＴ－Ⅱ则为选择性结合方式,表明这两种亚型在解铅毒功能上存在差异．     

Recent advances in analytical procedures for the detection of diarrhetic phycotoxins: a review

Okadaic acid and dinophysistoxins are produced by some marine unicellular algae from the plankton and also benthic microalgae and may accumulate in shellfish. These phycotoxins are involved in a gastrointestinal syndrome called diarrhetic shellfish poisoning (DSP), which occurs in humans after consumption of bivalve molluscs. Thousands cases of human poisonings in Europe were caused by consumption of toxic shellfish during the past decade. The rapid detection and the reliable determination of the main phycotoxins implicated in DSP are a major concern for governmental institutions in charge of the sanitary control of seafood safety. Analytical procedures for the detection and determination of DSP toxins can be classified as: bioassays, biochemical methods including immunoassays, or physicochemical methods. Although a large number of methods have been developed, none have been officially validated. A complete panel of tools for DSP toxin analysis should include screening, investigation, and confirmation methods. This paper presents a compilation of recent developments and optimisations of these methods. This revised version was published online in June 2006 with corrections to the Cover Date.     

Nogo-A蛋白在一氧化碳中毒大鼠海马组织中的动态表达

目的:观察一氧化碳中毒后大鼠海马组织中Nogo-A蛋白动态表达情况,探讨Nogo-A蛋白在一氧化碳中毒后神经系统损伤中的作用与影响。方法:随机数字法将雄性SD大鼠30只分为正常对照组(NC组)、CO中毒组(CO组)、CO中毒后24小时组(CO-24h)、CO中毒后48小时组(CO-48h)、CO中毒后7天组(CO-7d),每组各6只。CO气体腹腔注射染毒法建立一氧化碳中毒模型。建模后不同时间点利用免疫组织化学染色(IHC)、蛋白质免疫印迹技术检测(WB)Nogo-A蛋白在海马组织中的表达情况并分析其变化规律。结果:IHC结果表明NC、CO组、CO-24h组、CO-48h组、CO-7d组中Nogo-A蛋白平均光密度值分别为0.0928±0.0038、0.01172±0.0042、0.1452±0.0056、0.1271±0.0057、0.1088±0.0055;WB结果提示一氧化碳中毒后海马组织中Nogo-A蛋白的表达较NC组增高,在24h时表达达到高峰(P0.05);24h后表达开始逐步下降,至染毒第7天时,海马组织中Nogo-A蛋白的表达明显下降,但仍高于NC组(P0.05)。结论:在本研究中,大鼠海马组织中Nogo-A蛋白表达的增高与一氧化碳中毒相关;Nogo-A蛋白表达在24h时表达达到高峰;24h后表达开始逐步下降。     

Exploration of the possible effect on survival of lead-time associated with implementation of cancer patient pathways among symptomatic first-time cancer patients in Denmark

BackgroundImplementation of standardised cancer patient pathways (CPPs) has provided faster diagnosis of cancer. Cancer survival has improved during the same time period. Concern has been raised that the faster diagnosis may have introduced lead-time bias by elongating the period from diagnosis to death.AimWe aimed to analyse the possible effect of lead time on survival due to expedited cancer diagnosis after the implementation of national CPPs among incident cancer patients diagnosed through Danish primary care.Material and methodsWe used actual observed differences in diagnostic intervals to estimate the lead-time effect. We used data from sub-cohorts from the Danish Cancer in Primary Care (CaP) cohort of first-time cancer patients: before and after CPP implementation. To calculate differences in absolute survival, we estimated the survival function after advancing the date of diagnosis in the before cohort to an earlier point in time and hereby adjusting for lead time for nine cancer types and all combined by using Kaplan-Meier analysis.ResultsAdvancing the date of diagnosis implied that the absolute one-year survival increased from 68.5% to 69.4%. This accounted for 13% of the observed differences in absolute one-year survival from before to after CPPs.ConclusionThe lead time caused by shorter diagnostic intervals after implementation of Cancer Patient Pathways seems to explain less than 15% of the observed changes in the one-year survival estimates for cancer patients in Denmark.     

Loop-mediated isothermal amplification method for rapid detection of the toxic dinoflagellate Alexandrium, which causes algal blooms and poisoning of shellfish

The marine dinoflagellate genus Alexandrium includes a number of species that produce potent neurotoxins responsible for paralytic shellfish poisoning, which in humans may cause muscular paralysis, neurological symptoms and, in extreme cases, death. Because of the genetic diversity of different genera and species, molecular tools may help to detect the presence of target microorganisms in marine field samples. Here we employed a loop-mediated isothermal amplification (LAMP) method for the rapid and simple detection of toxic Alexandrium species. A set of four primers were designed based upon the conserved region of the 5.8S rRNA gene of members of the genus Alexandrium . Using this detection system, toxic Alexandrium genes were amplified and visualized as a ladder-like pattern of bands on agarose gels under isothermal condition within 60 min. The LAMP amplicons were also directly visualized by eye in the reaction tube by the addition of SYBR Green I. This LAMP assay was 10-fold more sensitive than a conventional PCR method with a detection limit of 5 cells per tube when targeting DNA from Alexandrium minutum . The LAMP assay reported here indicates the potential usefulness of the technique as a valuable simple, rapid alternative procedure for the detection of target toxic Alexandrium species during coastal water monitoring.     

A thermodynamic and crystallographic study of complexes of the highly preorganized ligand 8-hydroxyquinoline-2-carboxylic acid

The metal ion complexing properties of the ligand HQC (8-hydroxyquinoline-2-carboxylic acid) are reported. The structures of [Zn(HQCH)₂] · 3H₂O (1) and [Cd(HQCH)₂] · 3H₂O (2) were determined (HQCH = HQC with phenol protonated). Both 1 and 2 are triclinic, space group , with Z = 2. For 1 a = 7.152(3), b = 9.227(4), c = 15.629(7) Å,  = 103.978(7)°, β = 94.896(7)°, γ = 108.033(8)°, R = 0.0499. For 2 a = 7.0897(5), b = 9.1674(7), c = 16.0672(11) Å,  = 105.0240(10)°, β = 93.9910(10)°, γ = 107.1270(10)°, R = 0.0330. In 1 the Zn has a distorted octahedral coordination geometry, with Zn–N of 2.00 and 2.15 Å, and Zn–O to the protonated phenolic oxygens of 2.431 and 2.220 Å. The structure of 2 is similar, with Cd–N bonds of 2.220 and 2.228 Å, with Cd–O bonds to the protonated phenolate oxygens of 2.334 and 2.463 Å. The structures of 1 and 2, and isomorphous Ni(II) and Co(II) HQC complexes reported in the literature, show very interesting short (<2.5 Å) O–O distances in H-bonds involving the protons on the coordinated phenolates and lattice water molecules. These are discussed in relation to the possible role of short low-energy H-bonds in alcohol dehydrogenase in mediating the transfer of the hydroxyl proton of the alcohol to an adjacent serine oxygen.

The formation constants for HQC are determined by UV–Visible spectroscopy at 25 °C in 0.1 M NaClO₄ with Mg(II), Ca(II), Sr(II), Ba(II), La(III), Gd(III), Zn(II), Cd(II), Ni(II), Cu(II), and Pb(II). These show greatest stabilization with metal ions with an ionic radius above 1.0 Å. This is as would be expected from the fact that HQC forms two five-membered chelate rings on complex-formation, which favors larger metal ions. The ligand design concept of using rigid aromatic backbones in ligands to achieve high levels of preorganization, and hence the high log K values (for a tridentate ligand) and strong metal ion selectivities observed for HQC, is discussed.     

Four mixed-ligands lead(II) complexes based on 8-hydroxyquinolin (8-HQuin), [Pb(8-Quin)X]; X = 4-pyridinecarboxylate, acetate, thiocyanate and nitrate; structural and thermal studies

Lead(II) 8-hydroxychinolate complexes (8-Quin) containing four different anions, [Pb(8-Quin)X]; X = 4-pyridinecarboxylate (1), acetate (2), thiocyanate (3) and nitrate (4), have been synthesized and characterized by elemental analysis, IR-, ¹H NMR- and ¹³C NMR-spectroscopy. All these compounds were structurally characterized by single-crystal X-ray diffraction. The thermal stabilities of compounds 1–4 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The results show the influence of different counter-ions to form dimers in compound 2, one-dimensional polymer in compound 4 and two-dimensional polymer in compounds 1 and 3.     

Sonochemical synthesis of nano-sized metal-organic lead(II) polymer: A precursor for the preparation of nano-structured lead(II) iodide and lead(II) oxide

Nanoparticles of a new Pb^II metal-organic polymer, [Pb(μ-pyr)(μ-I)₂]_n (1), with a net-like morphology have been synthesized by the reaction of pyrazine with Pb(NO₃)₂ and NaI via sonochemical irradiation. Nano-structured PbI₂ and PbO were synthesized from compound 1 by calcination at argon and air atmospheres, respectively. The structure of 1 was determined by single crystal X-ray crystallography and the nano-structures were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The thermal stability of nano-sized and single crystalline samples of 1 were studied and compared.