Accumulation of cyanide and thiocyanate in haemodialysis patients.

BACKGROUND: Cyanide is a toxic agent, and its detoxification product, thiocyanate, may be a major pathogenetic substance in uraemia. Recent studies examining the myeloperoxidase(MPO)/thiocyanate system have suggested a link between thiocyanate and atherosclerosis. However, inaccuracies in conventional assays for cyanide and thiocyanate have limited the understanding of their metabolism in haemodialysis (HD) patients. METHODS: We used high-performance liquid chromatography to measure cyanide in erythrocytes and thiocyanate in plasma in 43 HD patients and in a group of 46 healthy controls that included 15 current smokers. To clarify the metabolic conversion of cyanide to thiocyanate in uraemic patients, we also measured cysteine and sulfate. We then used stepwise regression analysis to analyse factors that determine erythrocyte cyanide and plasma thiocyanate. RESULTS: Mean cyanide and thiocyanate were significantly greater in HD patients than in non-smoking controls. However, cyanide was far below lethal concentrations in dialysis patients. Thiocyanate was six to seven times greater in HD patients than in non-smoking controls, and decreases in thiocyanate following dialysis were only 19.3+/-3.5%. Multiple regression analysis showed a positive correlation between cyanide and thiocyanate in controls, but a negative correlation in HD patients. In patients, an inverse relationship between thiocyanate and BUN was also observed. CONCLUSIONS: The elevation of thiocyanate in patients undergoing dialysis probably is secondary to both limited efficiency of HD and deranged metabolism of cyanide and thiocyanate. Because thiocyanate is a preferred substrate for MPO, it may play a role in uraemic complications including cardiovascular events.     

抑制剂对酪氨酸酶影响的初步研究

采用酶动力学及聚丙烯酰胺凝胶电泳方法研究了ＮａＨＳＯ３、ＮａＮ３、ＫＳＣＮ、ＤＤＣ对酪氨酸酶的抑制作用。ＮａＨＳＯ３、ＮａＮ３、ＫＳＣＮ为非竞争性抑制作用，随着抑制剂浓度增加，酶活性逐渐减弱。当ＮａＨＳＯ３、ＮａＮ３、ＫＳＣＮ的浓度分别达到１．２ｍｍｏｌ／Ｌ１２。５ｍｍｏｌ／Ｌ１２．５ｍｍｏｌ／Ｌ时，酶活性的抑制率为１００％、５０％、２４％。ＤＤＣ对酪氨酸酶的抑制作用为竞争性抑制作用，其浓度达４ｍｍｏｌ／Ｌ时，酶活性１００％受到抑制。     

A molecular based diagnosis of positive blood culture in the context of viral haemorrhagic fever: proof of concept

ObjectivesThe aim of this study was to evaluate the possibility of using a PCR-based panel to identify bacterial and fungal bloodstream infections in the setting of suspected or confirmed viral haemorrhagic fever.MethodsThe accuracy of the FilmArray® Blood Culture Identification Panel (BCID) assay was assessed to identify the common bacterial and fungal pathogens associated with bloodstream infections after positive blood culture inactivation using a guanidinium thiocyanate containing buffer lysis that is commonly used for viral haemorrhagic fever molecular diagnostics.ResultsThe FilmArray® BCID panel assay detected 95% (19/20) of the pathogens analysed in this study by using both protocols with and without inactivation. Absolute consistency (100%) was observed in all isolates with phenotypes compatible with the presence of the antibiotic resistance genes mecA, vanA, vanB and blaKPC.ConclusionsThe FilmArray® BCID panel assay coupled to inactivation using a guanidinium thiocyanate containing buffer lysis represents a convenient, sensitive and specific diagnostic tool to detect some of the most pathogens associated with bloodstream infections in the context of a suspected or confirmed viral haemorrhagic fever.     

Induction and reversibility of thyroid proliferative changes in suckling rats given thiocyanate

Potassium thiocyanate given in the drinking water of pregnant rats led to decreased body weight in their 14-day-old offspring (27%) without altering thyroid weight. Reduction of the suckling rat's body weight could be explained be defective thyroxinemia (38). Plasma FT3 and TSH were unchanged after thiocyanate treatment. The biochemical changes were in agreement with the histological aspects of the hypothyroid animals. The typical pattern was hyperplastic goiter. Colloid volume was reduced compared with controls. Presence of resorbed peripheral vacuoles, a sign of thyroid hyperactivity, was disclosed by a three-fold increase in radioiodide (131I) uptake compared with controls. When the antithyroid drug was removed from the mother's milk, the pups'weight increased but did not reach control values. Plasma thyroid hormone levels returned to normal and even exceeded control values in spite of partial recovery of thyroid iodine content when thiocyanate treatment was stopped for ten days.     

Electronic Structure and Surface Properties of Copper Thiocyanate: A Promising Hole Transport Material for Organic Photovoltaic Cells

Considering the significance of hexagonal copper thiocyanate (β-CuSCN) in several optoelectronic technologies and applications, it is essential to investigate its electronic structure and surface properties. Herein, we have employed density functional theory (DFT) calculations to characterise the band structure, density of states, and the energy-dependent X-ray photoelectron (XPS) valence band spectra at variable excitation energies of β-CuSCN. The surface properties in the absence and presence of dimethyl sulfoxide (DMSO), a solvent additive for improving perovskite solar cells’ power conversion efficiency, have also been systematically characterised. β-CuSCN is shown to be an indirect band gap material (E_g = 3.68 eV) with the valence band edge demonstrated to change from being dominated by Cu-3d at soft X-ray ionisation photon energies to Cu-3p at hard X-ray ionisation photon energies. The adsorption energy of dimethyl sulfoxide (DMSO) on the (100) and (110) β-CuSCN surfaces is calculated at −1.12 and −0.91 eV, respectively. The presence of DMSO on the surface is shown to have a stabilisation effect, lowering the surface energy and tuning the work function of the β-CuSCN surfaces, which is desirable for organic solar cells to achieve high power conversion efficiencies.     

Copper thiocyanato complexes and cocaine – a case of ‘black cocaine’

The chemical composition of a black powder confiscated by German customs was elucidated. Black powders are occasionally used as a ‘transporter’ for cocaine and are obviously especially designed to cloak the presence of the drug. The material consisting of cocaine, copper, iron, thiocyanate, and graphite was approached by analytical tools and chemical modelling. Graphite is added to the material probably with the intention of masking the typical infrared (IR) fingerprints of cocaine and can be clearly detected by powder X‐ray diffraction (XRD) and Raman spectroscopy. Cu²⁺ and NCS^? ions, when carefully reacted with cocaine hydrochloride, form the novel compound (CocH)₂[Cu(NCS)₄] (CocH⁺ = protonated cocaine), which has been characterised by single crystal XRD, IR, NMR, UV/Vis absorption and EPR spectroscopy. Based on some further experiments the assumed composition of the original black powder is discussed. Copyright © 2014 John Wiley & Sons, Ltd.     

含碘的乳过氧化物酶-过氧化氢-硫氰化物系统对变异链球菌致龋性的影响

目的 研究含不同浓度碘（I-）的乳过氧化物酶-过氧化氢-硫氰化物系统（LPO-H2O2-SCN-）对变异链球菌生长、黏附、产水不溶性细胞外多糖以及葡萄糖基转移酶（GTF）活性的影响。方法 选用 S.mutans ATCC 25175为实验菌株。采用菌落形成单位（CFU）计数法进行生长实验;用分光光度计法测定细菌的黏附抑制率;用蒽酮法测定水不溶性细胞外多糖的质量浓度;用蒽酮法测定还原糖量,计算 GTF活性。结果 随着 I-浓度的增高,含I-的 LPO-H2O2-SCN-抗菌系统对 S.mutans致龋力的抑制作用增强。当I-≥100 μmol•L-1时,对 S.mutans的生长抑制明显高于对照组（ P<0.05）;且当I-≥1 000 μmol•L-1时,对S.mutans的生长抑制显著高于以硫氰酸盐（SCN-）为单底物的实验组（P<0.05）;当I-≥100 μmol•L-1时,对S.mutans的黏附抑制率达到50%以上,水不溶性细胞外多糖生成量明显减少（ P<0.05）, GTF活性也明显降低（P<0.05）。结论 通过增加 I-的浓度,可以抵消生理浓度的 SCN-的抑制作用,使含I-的LPO-H2O2-SCN-系统能显著抑制变异链球菌的生长、黏附、水不溶性细胞外多糖生成和GTF活性。     

Inhibitory Effects of Benzyl Isothiocyanate and Benzyl Thiocyanate on Diethylnitrosamine-induced Hepatocarcinogenesis in Rats

The effects of two aromatic thiocyanates, benzyl isothiocyanate (BITC) and benzyl thiocyanate (BTC), on diethylnitrosamine (DEN)-induced hepatocarcinogenesis were examined in rats. A total of 108 male ACI/N rats, 5 weeks old, were divided into 6 groups (18 rats in each). Group 1 was given a single i.p, injection of DEN (200 mg/kg body weight) one week after the start of the experiment and then kept on the basal diet until the end of the experiment (1 year). Groups 2 and 3 were treated with DEN and received dietary BITC (100 ppm) or BTC (100 ppm), respectively, throughout the experimental duration. Groups 4 and 5 were not given the carcinogen and were fed the diet containing BITC or BTC, respectively. Group 6 was kept on the basal diet alone and served as a control. Liver neoplasms were seen in Groups 1, 2 and 3. Incidence and average number of liver neoplasms in Group 2 were significantly smaller than in Group 1 ( P <0.0005 and P <0.001, respectively). The incidence of liver neoplasms in Group 3 was slightly lower than in Group 1, although the difference was not statistically significant. The numbers of glutathione S-transferase placental form (GST-P)-positive foci in Group 2 and γ-glutarnyltranspepridase (GGT)-positive foci in Groups 2 and 3 were significantly smaller than those in Group 1 ( P <0.001). The average and unit areas of GST-P- or GGT-positive foci in Group 2 or 3 were also significantly smaller than those in Group 1 ( P <0.05). These results suggest that BITC and BTC are chemopreventive agents for DEN-induced liver tumorigenesis.     

白细咳喘膏中芥子碱硫氰酸盐的含量测定

目的测定白细咳喘膏中芥子碱硫氰酸盐的含量,为制定该制剂的质量标准奠定基础。方法采用HPLC法,色谱柱:DIKMA inertsil(pH=3,5μm,250mm×4.6mm);以乙腈为流动相A,以3%醋酸溶液为流动相B,按比例进行梯度洗脱;检测波长:326nm;流速:1.0mL/min;柱温:室温。结果线性范围为0.8～4.0μg(r=0.9996,n=5),平均回收率100.83%,RSD=1.95%(n=5)。结论该法快速、简便,重现性和稳定性良好,可用于该制剂的质量控制。