Biological evaluation of intervertebral disc cells in different formulations of gellan gum‐based hydrogels

Gellan gum (GG)‐based hydrogels are advantageous in tissue engineering not only due to their ability to retain large quantities of water and provide a similar environment to that of natural extracellular matrix (ECM), but also because they can gelify in situ in seconds. Their mechanical properties can be fine‐tuned to mimic natural tissues such as the nucleus pulposus (NP). This study produced different formulations of GG hydrogels by mixing varying amounts of methacrylated (GG‐MA) and high‐acyl gellan gums (HA‐GG) for applications as acellular and cellular NP substitutes. The hydrogels were physicochemically characterized by dynamic mechanical analysis. Degradation and swelling abilities were assessed by soaking in a phosphate buffered saline solution for up to 170 h. Results showed that as HA‐GG content increased, the modulus of the hydrogels decreased. Moreover, increases in HA‐GG content induced greater weight loss in the GG‐MA/HA‐GG formulation compared to GG‐MA hydrogel. Potential cytotoxicity of the hydrogel was assessed by culturing rabbit NP cells up to 7 days. An MTS assay was performed by seeding rabbit NP cells onto the surface of 3D hydrogel disc formulations. Viability of rabbit NP cells encapsulated within the different hydrogel formulations was also evaluated by Calcein‐AM and ATP assays. Results showed that tunable GG‐MA/HA‐GG hydrogels were non‐cytotoxic and supported viability of rabbit NP cells. Copyright © 2012 John Wiley & Sons, Ltd.     

Diabetes and orthopaedic surgery: a review

Diabetes mellitus (DM) is common, estimated to affect 425 million people worldwide in 2017. It is a condition that is continually growing in prevalence and is often associated with multiple co-morbidities. Its multi-system effects on the body mean that its management can pose a challenge, even to more experienced clinicians. In orthopaedic practice, diabetic patients are commonly encountered owing to their increased fracture risk and complications of the disease such as diabetic foot. An appropriate knowledge of diabetes, its pathophysiology, immunology and the pharmacology of medications used in its treatment is essential, as the consequences of mismanagement can be grave. Optimal treatment of diabetics can often require the involvement of a wider multidisciplinary team. Complications that can be encountered in the perioperative and postoperative periods include, diabetic ketoacidosis, hyperosmolar hyperglycaemic state, surgical site infection and venous thromboembolism. This review outlines current concepts in the perioperative management of diabetes and its manifestations within orthopaedic surgery, with a focus on outcomes and complications. A review of the available literature reveals conflicting conclusions between studies, with no clear effect or consensus yet established for many issues. There is a need for a greater number of well-designed, high-quality, appropriately powered trials to establish the true effect of diabetes on outcomes in orthopaedic surgery.     

Importance of catalase in the disposal of hydrogen peroxide within human erythrocytes

The catalase within normal, intact human erythrocytes was completely inactivated with amino triazole. The rate of 14CO2 evolution, when the cells were subsequently incubated with 14C-labeled glucose, provided a measure of the rate at which NADPH was being oxidized by the glutathione peroxidase/reductase system for the disposal of H2O2. This rate was determined in control cells and in catalase-inactivated cells while the cells were exposed to H2O2, which was generated at various constant and predetermined rates by glucose oxidase. The results indicated that catalase handles approximately half of the generated H2O2. The glutathione peroxidase/reductase mechanism accounted for the other half. These results are in agreement with our earlier findings on erythrocytes of a subject with a genetic deficiency of catalase. However, an unexpected result with the present approach was the finding that the increased dependence on the glutathione peroxidase/reductase mechanism did not occur until greater than 98% of the catalase had been inactivated. The latter observation indicates that catalase and the glutathione peroxidase/reductase system function intracellularly in a manner very different from that previously ascribed to them. An explanation of the findings requires that the two methods of H2O2 disposal function in a coordinated way, such as a sequential action in which the glutathione peroxidase/reductase system is the rate-limiting step.     

不同病理分级的胰腺神经内分泌肿瘤的MRI征象对比分析及“主胰管绕道征”的诊断价值探讨

目的:对比分析G1、G2级胰腺神经内分泌肿瘤（pNEN）的MRI征象,探讨“主胰管绕道征”的诊断价值。方法:收集32例pNEN患者的临床资料,以术后病理学检查为金标准,定量分析G1、G2级临床指标及影像学指标的差异,并着重分析pNEN与主胰管的关系。结果:32例患者中,病理分级G1、G2、G3级的患者分别有12例、16例、4例,分别以胰尾、胰头、胰颈为主要发生部位。与G1级神经内分泌瘤（NET）相比,G2级NET肿瘤直径显著增大,不规则形态的病灶增多,边缘模糊,生物学行为出现明显恶性倾向,主胰管扩张、胰腺外侵犯及淋巴结/肝转移的发生率升高。G1级NET的MRI平扫信号均质程度高于G2级（P＜0.05）,但二者在增强MRI扫描的各个期象信号强度均无明显差异（P＞0.05）。28例NET患者中,22例（78.6%）出现主胰管绕道征;神经内分泌癌（NEC）患者无一例出现此征象。术前,28例NET的诊断准确率为78.6%（22/28）,存在6例误诊,其中,3例误诊为胰腺癌,2例误诊为囊腺瘤（癌）,1例误诊为胰腺假性囊肿。在原MRI诊断依据的基础上纳入“主胰管绕道征”,诊断准确率提高至89.3%（25/28）,但仍存在3例误诊,其中2例误诊为囊腺瘤（癌）,1例误诊为胰腺假性囊肿,排除了胰腺癌的误诊。结论:MRI对鉴别诊断良恶性pNEN有较高的准确性,但对部分G1与G2级NET仍存在一定的误诊率,主胰管绕道征可帮助减少出现胰腺癌误诊。     

Antimicrobial Activities of Skincare Preparations from Plant Extracts

In this study, Tithonia diversifolia Helms. (A Gray), Aloe secundiflora (Miller) and Azadirachta indica (A. Juss) plant extracts were used to make herbal soaps while Thevetia peruviana (Schum) seed oil was used to make a herbal lotion for skincare. The soaps were tested for the growth inhibition of Escherichia coli, and Candida albicans. The lotion was evaluated against Staphylococcus aureus and E.coli. Although Tithonia diversifolia soap exhibited the highest inhibitory effect on the test bacterial strains, it had the least inhibition against C. albicans. Results from this study indicated that the ‘Tithonia diversifolia’ soap would have superior skin protection against the tested bacteria but would offer the least skin protection against C. albicans. The herbal lotion inhibited S. aureus and E. coli in a concentration dependent manner, however, the inhibitory effect was more pronounced on S. aureus.     

The 100 most wired 2005: the quality connection

An analysis of this year's Most Wired Survey results shows for the first time that hospitals leading the way in information technology also have better outcomes. They use a wider array of IT tools to address quality, they conduct a larger percentage of clinical transitions via IT, and a larger percentage of their physicians enter orders themselves.