Cr(VI)‐induced genotoxicity and cell cycle arrest in human osteoblast cell line MG‐63

Occupational environments are major exposure routes to Cr(VI). However, Cr(VI) may also establish in bone tissues by ingestion or through Cr containing orthopaedic prostheses that, due to wear and corrosion, may release metal particles and ions potentially affecting bone tissue. The aim of this work was to evaluate the effects of clinically relevant concentrations of Cr(VI) in human osteoblasts, by integrating genotoxic effects, evaluated by the comet assay and cytokinesis‐blocked micronucleus assay (scoring the presence of micronucleus, nucleoplasmic bridges and nuclear division index), with the effects on cell cycle and cell viability. Human osteoblasts MG‐63 were in vitro exposed to Cr(VI) at concentrations ranging from 0.1 to 5 μm , for 24 and 48 hours. Results pointed out to a decrease of cell viability for both time exposures in a time‐ and dose‐dependent manner, which was related to cell cycle arrest and DNA damage. Chromosome abnormalities were also observed. Hence, these data suggest that cells arrested in the cell division with DNA damage may have followed cell death pathways, while some surviving ones still revealed DNA damage at chromosome level indicating abnormal cell division progression. In conclusion, Cr(VI) induced cytotoxic and genotoxic effects in human bone cells at concentrations that could be found in patients with metal‐on‐metal prostheses. In addition, the early onset of genotoxic damage induced by Cr(VI) at low concentrations after 24 hours of cell exposure alert to the relevance of periodic monitoring of patients for genotoxicity diagnosis after implantation of prostheses before clinical symptoms appear.     

糖尿病营养液对糖尿病大鼠糖脂代谢的影响

目的研究自配糖尿病营养液时糖尿病大鼠的饮食治疗作用,探讨其对糖脂代谢的影响及机制,为采用饮食营养治疗糖尿病提供实验依据。方法40只SD大鼠随机选取10只为正常对照组,其余大鼠采用腹腔注射链脲佐菌素方法制备糖尿病模型,随机分为糖尿病模型对照组、饮食治疗组、药物治疗组、饮食治疗组喂食添加高铬、硒及高纤维的糖尿病营养液．其他组喂食普通营养液;药物治疗组灌喂二甲双胍,疗程8周。检测血糖、血清胰岛素、胆固醇厦甘油三酯等指标。结果饮食治疗后．与模型对照组比较．血糖明显降低（P＜0．01）,而血清胰岛素升高（P＜0．01）,总胆固醇厦甘油三酯基本维持正常水平（P＞0．05）。结论所配制的糖尿病营养液可明显降低糖尿病大鼠血糖水平,改善其糖脂代谢。     

The Effect of Vanadium Content Coupling with Heat Treatment Process on the Properties of Low-Vanadium Wear-Resistant Alloy

The development of wear-resistant materials with excellent properties is of great research value in the manufacturing industry. In this paper, a new kind of low-vanadium wear-resistant alloy was designed and characterized to unveil the influence of vanadium content coupling with heat treatment on the microstructure, hardness, and abrasive wear property. The performances of commercial high chromium cast iron (HCCI) and the new low-vanadium wear-resistant alloy are compared. The alloy with 3 wt.% vanadium quenched at 900 °C and tempered at 250 °C, possessing VC, Mo₂C, and M₇C₃ distributed in the martensite matrix, displayed a wear resistance two times better than the HCCI. The results showed that the increase of vanadium content from 0.98 wt.% to 3.00 wt.% resulted in a decrease in the size of M₇C₃ and a more homogeneous distribution of M₇C₃. VC with a bimodal distribution is effective for impeding grooving or indenting by abrasives because of their high hardness, which plays a vital role in improving the wear resistance of low-vanadium wear-resistant alloy.     

Additive Technology: Update on Current Materials and Applications in Dentistry

Additive manufacturing or 3D printing is becoming an alternative to subtractive manufacturing or milling in the area of computer‐aided manufacturing. Research on material for use in additive manufacturing is ongoing, and a wide variety of materials are being used or developed for use in dentistry. Some materials, however, such as cobalt chromium, still lack sufficient research to allow definite conclusions about the suitability of their use in clinical dental practice. Despite this, due to the wide variety of machines that use additive manufacturing, there is much more flexibility in the build material and geometry when building structures compared with subtractive manufacturing. Overall additive manufacturing produces little material waste and is energy efficient when compared to subtractive manufacturing, due to passivity and the additive layering nature of the build process. Such features make the technique suitable to be used with fabricating structures out of hard to handle materials such as cobalt chromium. The main limitations of this technology include the appearance of steps due to layering of material and difficulty in fabricating certain material generally used in dentistry for use in 3D printing such as ceramics. The current pace of technological development, however, promises exciting possibilities.     

Immobilization of Hexavalent Chromium Using Self-Compacting Soil Technology

A study of immobilization of hexavalent chromium in the form of Na₂CrO₄ salt by self-compacting soils (SCS) is presented. Carbofill E additive was used as SCS binder. The efficiency of immobilization of Cr (VI) was evaluated by washing out chromium compounds from SCS samples. The influence of the nature of the soil and the content of Carbofill E and Na₂CrO₄ in the SCS samples on the efficiency of Cr (VI) immobilization was studied. It was found that the nature of the soil and the content of Carbofill E in the SCS samples affect the immobilization of Cr (VI). Moreover, increasing the Carbofill E content in SCS samples further increases Cr (VI) immobilization. X-ray diffraction studies of the samples with immobilized hexavalent chromium showed that part of the sample transforms from a readily soluble form of salt into oxide forms of chromium and calcium-chromium, which are practically insoluble in water.     

藻酸双酯钠铬配合物的制备及其理化性质的初步研究

目的 制备藻酸双酯钠(PSS)的铬配合物.并研究其溶解性、颜色、分子量等理化性质和光谱表征.方法 将PSS与三价铬离子在不同pH条件下进行络合.制备PSS铬配合物(PSS-Cr),采用正交实验优化制备条件.并采用UV、IR、HPGPC、原子吸收和电导滴定等分析方法 对PSS-Cr的结构和基本理化性质进行初步分析.结果 与结论 制备PSS-Cr的最适条件为:温度为50℃.pH值为7,PSS(以单糖计)与铬的摩尔比为2:1,在此条件下制备的PSS-Cr中的铬含量迭6.69%,重均相对分子质量为12188Da.     

Potential roles of chromium on inflammatory biomarkers in diabetes: A Systematic

Diabetes, as a low‐grade chronic inflammatory disease, causes disruption in proper function of immune and metabolic system. Chromium is an important element required for normal lipid and glucose metabolism. Chromium deficiency is correlated with elevation in cardiometabolic risk, which results from increased inflammation. This systematic review was conducted to discover the potential roles of chromium on inflammatory biomarkers. Eligible studies were all in vitro, animal and human studies published in English‐language journals from inception until October 2018. PubMed, Scopus, Embase, ProQuest and Google Scholar databases were searched to fined interventional studies from the effects of chromium on inflammatory biomarkers such as tumour necrosis factor a (TNF‐a), C‐reactive protein (CRP), interleukins, monocyte chemoattractant protein–1 (MCP‐1), intercellular adhesion molecule‐1 (ICAM‐1) and adipocytokines in hyperglycaemia and diabetes. Out of 647 articles found in the search, only 14 articles were eligible for analysis, three in vitro studies, eight animal studies and three human studies. Twelve of the 14 studies included in this review, chromium significantly decreased inflammatory factors. The findings of this review indicate, based on in vitro and in vivo studies, that chromium might have potential anti‐inflammatory properties, but some of the studies did not show anti‐inflammatory effects for chromium (two studies). There are only three studies in humans with controversial results. Therefore, more consistent randomized double‐blind controlled trials are needed to reach relevant clinical recommendations, as well as to determine the precise mechanism, of chromium on inflammation in diabetes.