Magnesium modification of a calcium phosphate cement alters bone marrow stromal cell behavior via an integrin-mediated mechanism

The chemical composition, structure and surface characteristics of biomaterials/scaffold can affect the adsorption of proteins, and this in turn influences the subsequent cellular response and tissue regeneration. With magnesium/calcium phosphate cements (MCPC) as model, the effects of magnesium (Mg) on the initial adhesion and osteogenic differentiation of bone marrow stromal cells (BMSCs) as well as the underlying mechanism were investigated. A series of MCPCs with different magnesium phosphate cement (MPC) content (0∼20%) in calcium phosphate cement (CPC) were synthesized. MCPCs with moderate proportion of MPC (5% and 10%, referred to as 5MCPC and 10MCPC) were found to effectively modulate the orientation of the adsorbed fibronectin (Fn) to exhibit enhanced receptor binding affinity, and to up-regulate integrin α5β1 expression of BMSCs, especially for 5MCPC. As a result, the attachment, morphology, focal adhesion formation, actin filaments assembly and osteogenic differentiation of BMSCs on 5MCPC were strongly enhanced. Further in vivo experiments confirmed that 5MCPC induced promoted osteogenesis in comparison to ot her CPC/MCPCs. Our results also suggested that the Mg on the underlying substrates but not the dissolved Mg ions was the main contributor to the above positive effects. Based on these results, it can be inferred that the specific interaction of Fn and integrin α5β1 had predominant effect on the MCPC-induced enhanced cellular response of BMSCs. These results provide a new strategy to regulate BMSCs adhesion and osteogenic differentiation by adjusting the Mg/Ca content and distribution in CPC, guiding the development of osteoinductive scaffolds for bone tissue regeneration.     

Magnesium lithospermate B acts against dextran sodiumsulfate-induced ulcerative colitis by inhibiting activation of the NRLP3/ASC/Caspase-1 pathway

This study aimed to observe the therapeutic effects of magnesium lithospermate B on acute and chronic colitis induced by dextran sodiumsulfate (DSS) and the role of inflammasome complex (NOD-like receptor protein, NLRP; apoptosis-associated speck-like protein containing, ASC; caspase-1). Establishment of acute and chronic colitis models were by using 5% DSS oral administration in BALB/C male mice. Magnesium lithospermate B (240 mg/kg body weight) was given by subcutaneous injection. Samples were collected for biomarker assay, histological examination, immunohistochemical evaluation and western blot. There was obvious increase in TNF-α level and NLPR3, ASC, and caspase-1 expressions in acute and chronic colitis groups compared with the normal control. Significant decrease of the tumor necrosis factor-α level and the expressions of NLPR3, ASC, and caspase-1 were observed after treatment with magnesium lithospermate B. This study showed that magnesium lithospermate B could be used to treat acute and chronic colitis by inhibiting the activation of the NLRP3/ASC/Caspase-1 pathway.     

丙戊酸钠治疗对血清瘦素、体重指数的影响

目的服用丙戊酸钠(VPA)抗癫痫治疗的患者,15%～70%的成人可发生体重增加[1-2],而瘦素在体重和能量平衡的调节中起重要影响,近年来许多研究表明VPA引起的体重改变可能与瘦素有关。探讨丙戊酸钠抗癫痫治疗对血清瘦素的影响,该影响与患者体重改变的相关性,以及瘦素的可能机制。方法以丙戊酸钠治疗超过3个月的33例癫痫患者为治疗组,20例未经丙戊酸钠治疗癫痫患者作为对照组来比较,检测患者体重、身高、血清瘦素水平,比较两组的体重指数(BMI)、血清瘦素水平。结果丙戊酸钠治疗组的血清瘦素(8.8503±4.7924)ug/ml与对照组(2.8490±1.3962)ug/ml比较有增高,治疗组BMI(23.7202±2.5182)高于对照组(20.8468±1.6815)。结论丙戊酸钠治疗可能引起血清瘦素、体重指数增高,很可能通过诱导导致瘦素抵抗的机制之一,从而导致患者体重增加。     

丙戊酸钠合并氯丙嗪治疗精神分裂症的对照研究

目的观察丙戊酸钠合用氯丙嗪治疗精神分裂症的疗效与不良反应。方法符合CCMD-3诊断标准的精神分裂症住院患者,丙戊酸钠合用氯丙嗪组(研究组)35例,单用氯丙嗪组(对照组)31例。以PANSS、CGI、TESS量表评定观察12周。结果研究组总体疗效自第2周起明显优于对照组(P<0.05),其中研究组兴奋症状分及攻击因子分自第4周起缓解明显优于对照组(P<0.05)。研究组较对照组副反应较少且程度较轻(P<0.05)。结论丙戊酸钠合并氯丙嗪治疗精神分裂症疗效肯定,安全性与耐受性较好。     

The Effects of Zero Magnesium Dialysate and Magnesium Supplements on Ionised Calcium Concentration in Patients on Regular Dialysis Treatment

The effect of oral magnesium carbonate aluminium hydroxide onserum ionised calcium, total calcium, aluminium and magnesium,was assessed in 31 patients with chronic renal failure, duringand after one haemodialysis. The behaviour of ionised calcium and total calcium was the samein both groups. Each showed a slight fall during dialysis, whichwas not significant. Serum total calcium was 0.2–0.3 mmol/l(0.8–1.2 mg/dl) greater throughout the period of dialysisin the group taking aluminium hydroxide. Serum magnesium andaluminium were both lower in the group treated with magnesiumcarbonate. In the group taking magnesium carbonate, serum magnesium concentrationsfell markedly during dialysis, but otherwise were maintainedwithin the reference range by the use of a magnesium-free dialysate.These results show the effectiveness of magnesium carbonateoral phosphate-binding agents and zero magnesium dialysate inreducing serum aluminium without affecting the behaviour ofserum calcium fractions during dialysis.     

Juvenile Myoclonic Epilepsy: Factors of Error Involved in the Diagnosis and Treatment

Juvenile myoclonic epilepsy (JME), a common form of idiopathic generalized epilepsy, has a distinct clinical and electroencephalographic profile. Often JME is not recognized, with serious consequences on the sufferers. We examined factors contributing to the missed diagnosis even in an epilepsy clinic. Of 70 JME patients, 66 (91.4%) were not diagnosed on referral and 22 (33%) were not initially recognized in the epilepsy clinic. The correct diagnosis was established after a mean of 8.3 +/- 5.5 years from disease onset and an interval of 17.7 +/- 10.4 months from first evaluation in the epilepsy clinic. Myoclonic jerks, the hallmark of the disease, were not usually reported by patients. Similarly, relevant questioning may not be included in the history. Absence seizures antedating jerks by many years, myoclonic jerks reported as unilateral, generalized tonic-clonic seizures occurring during sleep and focal EEG abnormalities are other factors contributing to not recognizing JME. Our study reemphasizes the need to have not only a correct seizure diagnosis but also a correct epilepsy-disease diagnosis.     

Free plasma magnesium following glucose loading in healthy humans

The recognized existence of a circadian pattern in extracellular magnesium balance might mirror either an inherent rhythm in the homeostasis of this ion or dietary factors. Since in vitro insulin enhances cellular magnesium uptake, the circadian rhythm in extracellular magnesium metabolism might be modulated at least in part by carbohydrate intake. To assess this hypothesis, the effects of oral glucose loading on plasma total and ionized magnesium were investigted in lean healthy humans with a negative family history for essential hypertension and diabetes mellitus. Plasma total and ionized magnesium was similar before glucose loading and 30, 60, 90, 180, and 210 min thereafter. It is therefore concluded that in healthy humans the circadian pattern of extracellular magnesium is not modulated by the metabolic and hormonal mechanisms that adjust the concentration of glucose. Received: 5 February 1997 / Accepted in revised form: 14 April 1997     

日晒海盐工人机体内高镁反应

报道福建某盐场从事日晒海盐生产人工机体内高镁对心血管系统的影响，通过现场空气、饮水、主良的镁含量测定，并对进入机体途径进行分析，得出空气、卤水接触、饮水为机体镁增高的主要来源。不同对象头发镁含量测定结果显示，以接触卤水、劳动强度大的盐工最高，并随机体内镁含量增高，出现血压偏低、心率减慢、心电图Ｐ－Ｒ间期延长、ＱＲＳ波增宽、Ｔ波高尖等机体高镁反应，与临床高镁血症相似。     

分娩期应用硫酸镁对妊高征母儿预后的影响

目的 :探讨妊高征患者分娩期应用硫酸镁对母儿预后的影响。方法 :回顾性分析近 10年来在该院分娩的妊高征患者分娩期应用硫酸镁情况的临床资料。结果 :分娩的妊高征患者共 82 6例 ,其中分娩期硫酸镁治疗组 4 2 2例 ,未治疗组 4 0 4例。轻、中、重度妊高征分娩期硫酸镁用量分别为 :4 .33± 1.14 g ;5 .5 0± 1.6 4 g ;9.0 0± 1.70g。不同程度妊高征硫酸镁治疗组与未治疗组比较 ,产程、产后出血量及新生儿窒息率差异均无显著意义 (P >0 .0 5 ) ,而两组中轻、中度妊高征分别与重度妊高征比较 ,产后出血量差异均有显著意义 (分别P <0 .0 1,P <0 .0 5 )。硫酸镁配伍酚妥拉明预防子痫 (n =89)较单用酚妥拉明治疗组 (n =5 4 )子痫发生率显著降低 (P <0 .0 5 )。结论 :妊高征患者分娩期适量应用硫酸镁对母儿是安全的 ,有利于预防子痫等并发症。     

镁对急性心肌梗塞的治疗作用

本文报道了镁剂治疗急性心肌梗塞的疗效，结果表明：镁能有效地控制急性心肌梗塞病人的心律失常，能明显改善心功能不全的临床表现，缓解胸痛发作及减少再梗塞的发生，镁剂治疗急性心肌梗塞疗效显著。