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.     

Epicardial adipose tissue is increased in patients with systemic lupus erythematosus

ObjectiveMorbidity and mortality secondary to premature cardiovascular disease (CVD) in systemic lupus erythematosus (SLE) remain significant issues. The pathogenesis of CVD in SLE patients has not been fully explored. Epicardial adipose tissue (EAT) is believed to contribute to atherosclerosis development, through a paracrine and systemic inflammatory effect. We measured EAT volume in 162 SLE patients and 86 matched controls to assess the association of EAT with markers of atherosclerosis, cardiovascular risk and immunoactivation.MethodsClinical and laboratory characteristics collected included anthropomorphic measures, disease activity and damage indices, blood pressure measurement, lipid profile, inflammatory indices, adipokine levels and measures of adiposity. Coronary artery calcium (CAC) and EAT volume were measured using non-contrast cardiac computed tomography.ResultsEAT volume was greater in patients with SLE [(mean ± SD) 96.8 ± 45.9 cm³] than controls (78.2 ± 40.7 cm³; P = 0.001). The EAT volume was 31% larger (95% CI, 16.5%–47.4%) in SLE patients than controls (P < 0.001 adjusted for age, sex, and race; after additional adjustment for waist circumference P = 0.007). Within SLE patients, after adjusting for age, race, sex, and waist circumference, EAT volume was associated with cumulative corticosteroid dose (P = 0.007), current corticosteroid use (P < 0.001), HDL cholesterol (P = 0.033), and triglycerides (P = 0.005). EAT was significantly correlated with CAC score (P < 0.001), but the association was attenuated after adjustment for Framingham risk score (P = 0.051).ConclusionThe increased EAT volume seen in SLE patients is associated with corticosteroid use. Corticosteroids could have adverse cardiovascular effects in SLE via an increase in EAT volume, a marker of risk in the general population.     

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.     

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.     

Assessment of behavioral sequelae of traumatic and chemical CNS insult

Twenty patients with traumatic head injury and 20 patients with neurotoxic chemical exposure completed a 68-item Behavior Inventory listing preinsult versus postinsult behavior presence or absence for each item. Forty controls completed the same inventory, covering approximately the same intervals of time involved with CNS insult group. Whereas controls showed nonsignificant behavior changes on any variable, clinical groups reported significant behavior change on the majority of behavioral variables. There were some differential changes between the two clinical groups. Findings suggest an approach to assessing behavior changes due to CNS insult.     

Patient preferences with regard to ideal therapist characteristics

Sixty patients seen at a VA Outpatient Mental Hygiene Clinic described their perceptions of ideal therapist characteristics on a 128-item checklist and subsequently described their own therapist on the same checklist. Patients then rated satisfaction with treatment on a 5-item questionnaire. There was good agreement among patients on both characteristics of the ideal therapist and satisfaction with various aspects of therapy. Data suggest that there is consensus on what patients expect in a therapist and also suggest a relationship between how well therapists meet these expectancies and how effective patients consider their therapy.     

Naloxone prevents increased atrial natriuretic peptide release during regional myocardial ischaemia and stunning in awake dogs

Background. Atrial natriuretic peptide (ANP) release is increasedin patients with ischaemic left ventricular dysfunction. A beneficialeffect of naloxone on recovery from myocardial stunning wasshown previously. The aim of this study was to investigate theeffects of naloxone on ANP release during regional myocardialischaemia and stunning in awake dogs. Methods. Ten dogs were chronically instrumented for measurementof heart rate, left atrial, aortic, and left ventricular pressure(LVP), LV dP·dt_max/min^–1, and myocardial wall-thickeningfraction. An occluder around the left anterior descending artery(LAD) allowed induction of reversible ischaemia in the LAD-perfusedmyocardium. Each dog underwent two ischaemic episodes (randomizedcrossover fashion; separate days): 10 min of LAD occlusion (1)after application of naloxone (63 µg kg^–1), and(2) without naloxone. ANP levels were measured at baseline (BL)and at predetermined time points until complete recovery ofmyocardial stunning occurred. Results. LAD ischaemia-induced release of ANP (peak level: 182(30) vs 27 (7) pg ml^–1 BL) only in the control group withoutnaloxone. Between 1 and 180 min of reperfusion, ANP levels weresignificantly higher only in the control group (P<0.05). Conclusion. Pre-ischaemic application of naloxone prevents thisischaemia-induced ANP-release in conscious dogs. Br J Anaesth 2002; 88: 87–93     

Neurological and emotional sequelae of exposure to ethylene oxide

Subjects were 66 traumatic brain-injured (TBI) versus 22 neurotoxic-injured individuals (due to ethylene oxide - ETO). Among significant findings were higher cognitive functioning for the TBI group for FSIQ, VIQ and PIQ; elevated scores on MMPI scales 1, 2, 3 and 8 for both groups, and elevated anxiety scores on the MAACL for the ETO group relative to the TBI group. Results indicate a more severe impact of ETO exposure in the areas of intellectual functioning and anxiety.