1.
Infusion of calcium and magnesium for oxaliplatin-induced sensory neurotoxicity in colorectal cancer: a systematic review and meta-analysis.
Wu, Z, Ouyang, J, He, Z, Zhang, S
European journal of cancer (Oxford, England : 1990). 2012;(12):1791-8
Abstract
BACKGROUND It is hypothesised that infusion of calcium and magnesium (Ca/Mg) can reduce the occurrence of oxaliplatin-related sensory neurotoxicity. However, more recent data have drawn a controversial picture concerning this topic. METHODS A comprehensive literature search was performed using Medline, Embase, Cochrane Library and Google Scholar database up to 1st August 2011. Keywords for the search were: calcium, magnesium and oxaliplatin. The odd ratio (OR) for neurotoxicity and relative risk (RR) for tumour response rate were calculated. RESULTS Seven studies (four randomised controlled trials (RCTs) and three cohorts) including a total of 1238 participants met our criteria. Meta-analysis of three RCT studies that reported in National Cancer Institute-Common Toxicity Criteria (NCE-CTC) showed that OR for neurotoxicity of Grade ~2 was not significant (OR 0.47; 95%confidence interval (CI) 0.22-1.00, P homogeneity = .729). The OR was also not significant in All Grades (OR 3.15, 0.32-31.35, P homogeneity = .952) and Grade 3 subgroup (OR 1.64, 0.30-9.00, P homogeneity = .656). No statistically significant difference was observed in RR for tumour response rate. (RR = 0.91, 0.78-1.06, P homogeneity = .33) CONCLUSIONS This meta-analysis does not support the hypothesis that infusion of Ca/Mg reduces the occurrence of neurotoxicity in oxaliplatin-treated patients with colorectal cancer measuring with NCE-CTC criteria. On the other hand, our results support the hypothesis that administrations of Ca/Mg do not impair the efficacy of oxaliplatin-based chemotherapy. However, large-scale randomised, controlled clinical trials will be required to confirm these hypotheses.
2.
Interaction between a high purity magnesium surface and PCL and PLA coatings during dynamic degradation.
Chen, Y, Song, Y, Zhang, S, Li, J, Zhao, C, Zhang, X
Biomedical materials (Bristol, England). 2011;(2):025005
Abstract
In this study, polycaprolactone (PCL) and polylactic acid (PLA) coatings were prepared on the surface of high purity magnesium (HPMs), respectively, and electrochemical and dynamic degradation tests were used to investigate the degradation behaviors of these polymer-coated HPMs. The experimental results indicated that two uniform and smooth polymer films with thicknesses between 15 and 20 µm were successfully prepared on the HPMs. Electrochemical tests showed that both PCL-coated and PLA-coated HPMs had higher free corrosion potentials (E(corr)) and smaller corrosion currents (I(corr)) in the modified simulated body fluid (m-SBF) at 37 °C, compared to those of the uncoated HPMs. Dynamic degradation tests simulating the flow conditions in coronary arteries were carried out on a specific test platform. The weight of the specimens and the pH over the tests were recorded to characterize the corrosion performance of those samples. The surfaces of the specimens after the dynamic degradation tests were also examined. The data implied that there was a special interaction between HPM and its polymer coatings during the dynamic degradation tests, which undermined the corrosion resistance of the coated HPMs. A model was proposed to illustrate the interaction between the polymer coatings and HPM. This study also suggested that this reciprocity may also exist on the implanted magnesium stents coated with biodegradable polymers, which is a potential obstacle for the further development of drug-eluting magnesium stents.
3.
Electrodeposition of Ca-P coatings on biodegradable Mg alloy: in vitro biomineralization behavior.
Song, Y, Zhang, S, Li, J, Zhao, C, Zhang, X
Acta biomaterialia. 2010;(5):1736-42
Abstract
Preparing stabilized apatite on biodegradable Mg alloy may improve biocompatibility and promote osteointegration. In the present work, three kinds of Ca-P coatings, brushite (DCPD, CaHPO(4).2H(2)O), hydroxyapatite (HA, Ca(10)(PO(4))(6)(OH)(2)) and fluoridated hydroxyapatite (FHA, Ca(5)(PO(4))(3)(OH)(1-)(x)F(x)) are fabricated by electrodeposition on a biodegradable Mg-Zn alloy. The crystalline structures, morphologies and compositions of these Ca-P coatings have been characterized by X-ray diffrection, scanning electron microscopy and energy-dispersive spectoscopy. The effects of these coatings on the degradation behavior and mineralization activity of the Mg-Zn alloy have also been investigated. The experimental results showed that these coatings decreased the degradation rate of Mg-Zn alloy, while the precipitates on the uncoated and DCPD-coated Mg-Zn alloy in modified simulated biological fluid had low Ca/P molar ratios, which delayed bone-like apatite formation. Both the HA and FHA coating could promote the nucleation of osteoconductive minerals (bone-like apatite or beta-TCP) for 1month. However, the HA coating transformed from DCPD through alkali heat treatment was fragile and less stable, and therefore its long-term corrosion resistance was not satisfactory. Instead, the FHA was more stable and had better corrosion resistance, and thus it should be better suited as a coating of Mg implants for orthopedic applications.