锌精矿生产硫酸项目职业病危害调查及评价

目的调查分析以锌精矿为原料生产硫酸的生产过程中存在的职业病危害因素及危害程度。方法采用现场职业卫生学调查、检测和检查表等方法进行调查与评价。结果该项目的主要职业病危害因素有粉尘、硫酸、三氧化硫、二氧化硫、噪声、工频电场、高温等,基本符合职业接触限值。结论在目前的生产状态下该项目的职业病防护措施是有效可行的。建议增加应急救援措施。     

维生素A和锌过量摄入对幼龄大鼠脾脏抗氧化能力的影响

目的:探讨维生素A(VitA)和锌(Zn)摄入过量对幼龄大鼠脾脏抗氧化能力的影响,并为VitA和Zn的营养补充上限的制定提供实验室参考依据。方法:通过灌胃造成VitA摄入10倍于推荐摄入量(RNI)的大鼠动物模型,摄入剂量为0.48g/kg,Zn摄入20倍于RNI的大鼠动物模型,摄入剂量为1.00g/kg,并按相同剂量设立联合过量组,同时设立对照组。在实验第4周末处死全部大鼠,制备脾脏组织匀浆,测定大鼠脾脏总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量。应用SPSS15.0统计软件对其测定结果进行统计分析。结果:实验组脾脏中T-AOC、SOD、GSH-Px、CAT活性明显降低,MDA含量显著升高,与对照组相比差异有统计学意义(P0.05),而且VitA和Zn联合过量组较之VitA和Zn单一过量组差异更明显。结论:过量补充VitA和Zn可降低幼龄大鼠脾脏的抗氧化能力。     

果酸联合甘草锌颗粒治疗寻常型痤疮的疗效观察

目的观察果酸联合甘草锌颗粒治疗寻常型痤疮的疗效。方法将患者随机分为治疗组和对照组,治疗组给予口服甘草锌颗粒,同时每隔3周进行1次果酸治疗;对照组仅予口服甘草锌颗粒治疗。疗程为12周。结果治疗组与对照组的总有效率分别为82.5%、65%,治疗组的疗效明显优于对照组,2组疗效比较差异具有统计学意义(P0.05)。结论果酸联合甘草锌颗粒治疗寻常型痤疮疗效较好,安全性高,具临床推广价值。     

Oral zinc augmentation with vitamins A and D increases plasma zinc concentration: Implications for burden of disease

A study evaluating zinc supplementation in patients with Alzheimer's disease yielded variable zinc plasma levels in spite of positive cognitive and physiological results. In an attempt to raise and sustain plasma zinc levels, a single patient was given 15 mg zinc/day with various combinations of vitamins. A sustained raise in plasma zinc concentration (and therefore its potential bioavailability) was obtained only when the zinc was augmented with both vitamins A and D (in RDA concentrations). In order to verify these results, a follow-up study was conducted in 70 volunteers. Seven groups of 10 healthy subjects received various combinations of zinc and the two vitamins A and D, namely: zinc, vitamin A, vitamin D, zinc plus vitamin A, zinc plus vitamin D, vitamins A and D, and zinc plus vitamins A and D. Plasma zinc levels were determined at baseline, 3 weeks and 6 weeks. Plasma zinc levels increased significantly (p < 0.02) from 11.82 (±2.60) to 13.32 (±3.04) μm/L only in the group receiving the combination of zinc and vitamins A and D. This novel method of increasing plasma zinc levels by the augmentation of vitamins A and D may have implications for the reduction of burden of disease.     

Clusterin/Apolipoprotein J up-regulation after zinc exposure, replicative senescence or differentiation of human haematopoietic cells

Clusterin/Apolipoprotein J (CLU) is a cellular senescence biomarker implicated in several physiological processes. In this work we have investigated CLU expression and function in human haematopoietic cells. We found that early passage human T cell clones (TCC) express minimal endogenous amounts of CLU, which are significantly elevated in late passage cells. Moreover, exposure of TCC to increased levels of the essential micronutrient zinc in culture resulted in intense induction of CLU. Because haematopoietic cells cease proliferation following induction of terminal differentiation, we also studied the expression profile of CLU in the leukemic progenitor cell lines K562 and HL-60. We found that, like TCC, both cell lines express minimal endogenous levels of CLU in their actively proliferating state. However, when induced to differentiate into their distinct cell types, CLU was found to be up-regulated specifically in those cells expressing the main differentiation markers. Enforced stable over-expression of CLU in K562 cells inhibited the expression of the CD14 differentiation marker and blocked differentiation to either monocytes/megacaryoblasts or to erythrocytes. Overall, our results suggest that CLU is actively involved in both replicative senescence and terminal differentiation in different types of human haematopoietic cells.Presented at the ZincAge Conference, Madrid, February 10–13, 2006.     

Effect of zinc ions on apoptosis in PBMCs from healthy aged subjects

Immunosenescence features, such as thymic involution, alteration of T-cell repertoire, autoimmunity and accumulation of memory/effector T cells, may be the result, at least in part, of a zinc deficiency, which is often observed during ageing. Zinc, as essential trace element, affects the immune system function and it is an important regulator of apoptosis of immune cells. In this study we addressed the question whether zinc supplementation in vitro at physiological doses can affect spontaneous and oxidative stress-induced apoptosis in peripheral blood mononuclear cells from subjects of three different age groups: young (mean age 28 years), old (mean age 72 years) and nonagenarians. We studied different parameters related to apoptosis (phosphatydilserine exposure, mitochondrial membrane potential, caspase 3 cleavage) and we found that zinc, while decreasing spontaneous apoptosis, can increase oxidative stress-induced apoptosis in an age-related fashion, being this effect more evident in nonagenarians than in old or young subjects. In particular, zinc can increase late apoptosis/necrosis, a phenomenon that could trigger unnecessary inflammation in vivo. We surmise that these age-associated alterations in susceptibility to apoptosis may be due to a different effect of zinc on T cell subsets, that are altered in very old people, and finally that the zinc deficiency, which is often observed in aged subjects, could be a compensatory mechanism to counteract the inflammatory status of the elderly.Presented at the ZincAge Conference, Madrid, February 10–13, 2006.     

Polymorphisms in MT1a gene coding region are associated with longevity in Italian Central female population

Metallothioneins (MTs) play a pivotal role in zinc-related cell homeostasis because of their high affinity for zinc, which is in turn fundamental for immune response and antioxidant activity. MTs regulate zinc homeostasis by binding zinc and releasing zinc at the occurrence for immune response. The zinc release by MT is very limited in chronic inflammation and ageing. Some polymorphisms of MTs gene, in particular MT1a sub-isoform, may affect this release that is a problem still unresolved in ageing. The screening in the present paper of two polymorphisms in MT1a gene has revealed for the first time that the polymorphism corresponding to a A/C (Asp/Thr) transition at 647 nt position in the Mt1a coding region is the more involved in the longevity, at least in old women, rather than the other corresponding to A/G (Lys/Arg) transition at 1,245 nt position. Concomitantly, for the +647 MT1a polymorphism, old and very old female with Asp/Asp genotype (called C-carriers) display higher zinc release by MT (detected by Zinpyr-1 fluorescent probe in presence of NO donor), low MT levels and reduced IL-6 plasma concentrations, suggesting its involvement in longevity and in lower inflammatory status. This fact is confirmed by the analysis of haplotypes in which the allele Asp is more involved in longevity. Therefore the +647 MT1a polymorphism more affects MTs induction and zinc release, which are indispensable to undertake the inflammatory status under control and subsequently to reach healthy longevity.Presented at the ZincAge Conference, Madrid, February 10–13, 2006.