Is there significant variation in the material properties of four different allografts implanted for ACL reconstruction

The aims of our study were to: (1) determine if there are differences in the material properties of tendon obtained from implanted tibialis anterior, achilles, bone-patella- bone and tibialis posterior allografts; (2) determine the variability in material properties between the implanted specimens. A total of 60 specimens were collected from fresh frozen allografts implanted at ACL reconstruction. Specimens collected included 15 tibialis anterior, 15 tibialis posterior, 15 achilles and 15 bone-patella-bone tendons. Each specimen was mounted in a custom made cryogrip. The mounted specimens were loaded onto a MTS Testline servo-hydraulic testing machine in a uni-axial tensile test configuration. Specimens were subjected to a strain rate of 5% per second until the ultimate tensile stress (UTS), failure strain and high strain modulus was calculated for each specimen after being normalized for specimen dimensions. Individual material properties were tested using one way analysis of variance (ANOVA) and post hoc Tukey’s B test with a P value of <0.05 considered significant. Homogeneity of variance was assessed using the Levene’s test. As a result, no significant difference was found between all four grafts with regards to UTS, failure strain or high strain linear modulus. The UTS was plotted against the modulus demonstrating a linear relationship which is typical of soft tissues. Significant variability in the results were observed. In conclusion, there was no significant statistical difference between the material properties of the four tendon allografts tested. But significant variability in results was observed within groups and between groups, which may provide one explanation for the range of results in allograft ACL reconstruction reported in the literature.     

IMPaCT Back study protocol. Implementation of subgrouping for targeted treatment systems for low back pain patients in primary care: a prospective population-based sequential comparison

Background  

Prognostic assessment tools to identify subgroups of patients at risk of persistent low back pain who may benefit from targeted treatments have been developed and validated in primary care. The IMPaCT Back study is investigating the effects of introducing and supporting a subgrouping for targeted treatment system in primary care.     

Surface display of IgG Fc on baculovirus vectors enhances binding to antigen-presenting cells and cell lines expressing Fc receptors

Recombinant baculoviruses (recBV) were constructed with dual cassettes for constitutive expression of human IgG Fc following infection of insect cells and the structural proteins of hepatitis C virus (core, E1 and E2) following transduction of mammalian cells. The IgG Fc was expressed in insect cells as a fusion protein with the signal sequence and transmembrane region of either the native baculovirus envelope protein gp64 or the human transferrin receptor as a type I or type II integral membrane protein, respectively. The IgG Fc fusion proteins formed functional homodimers on the surface of recBV-infected insect cells and were incorporated into the envelope of recBV particles during egress from the infected cell. Both pseudotyped recBV bound specifically to recombinant soluble FcγRIIα receptor and to cell lines and antigen-presenting cells expressing Fc receptors (FcRs). These novel baculoviral vectors, which target cells of the immune system that express FcRs, have potential applications for vaccination or gene therapy.     

Post-Operative Assessment of an Implant Fixation in Anterior Cruciate Ligament Reconstructive Surgery

The objective of this paper is to numerically simulate the behaviour of an anterior cruciate ligament (ACL) reconstructed knee using interference screw fixation under a single cycle loading or a cyclic loading test and to compare the numerical results with experimental tests using porcine samples of knee joint. A hyper-elastic material model was used to model the tendon graft and evaluate its elongation during continuous and cyclic tensile loading. The rigidity of the interference screw fixation was also examined using the finite element based numerical model. The finite element model uses the benefit of an anatomical 3D geometry of the tibial bone and tendon graft which was created from a CT scan of a patient.     

Evaluating the Angina Plan in Patients Admitted to Hospital with Angina: A Randomized Controlled Trial

The aim of this trial was to evaluate the Angina Plan (AP), a cognitive‐behavioral nurse‐facilitated self‐help intervention against standard care (SC). A randomized controlled trial of 218 patients hospitalized with angina assessed participants predischarge and 6 months later. Data were collected during a structured interview using validated questionnaires, self‐report, and physiological measurement to assess between group changes in mood, knowledge and misconceptions, cardiovascular risk, symptoms, quality of life, and health service utilization. The intention‐to‐treat (ITT) analysis found no reliable effects on anxiety and depression at 6 months. AP participants reported increased knowledge, less misconceptions, reduced body mass index (BMI), an increase in self‐reported exercise, less functional limitation, and improvements in general health perceptions and social and leisure activities compared to those receiving SC. Sensitivity analysis excluding participants with high baseline depression revealed a statistical significant reduction in depression levels in AP compared to the SC participants. Analysis excluding participants receiving cardiac surgery or angioplasty removed the ITT effects on physical limitation, self‐reported exercise and general health perceptions and the improvements seen in social and leisure activities, while adaptive effects on knowledge, misconceptions and BMI remained and between‐group changes in depression approached significance. Initiating the AP in a secondary care setting for patients with new and existing angina produces similar benefits to those reported in newly diagnosed primary care patients. Further evaluation is required to examine the extent of observed effects in the longer term.     

Diabetes prevalence and socioeconomic status: a population based study showing increased prevalence of type 2 diabetes mellitus in deprived areas

OBJECTIVE: To establish the relation between socioeconomic status and the age-sex specific prevalence of type 1 and type 2 diabetes mellitus. The hypothesis was that prevalence of type 2 diabetes would be inversely related to socioeconomic status but there would be no association with the prevalence of type 1 diabetes and socioeconomic status. SETTING: Middlesbrough and East Cleveland, United Kingdom, district population 287,157. PATIENTS: 4313 persons with diabetes identified from primary care and hospital records. RESULTS: The overall age adjusted prevalence was 15.60 per 1000 population. There was a significant trend between the prevalence of type 2 diabetes and quintile of deprivation score in men and women (chi 2 for linear trend, p < 0.001). In men the prevalence in the least deprived quintile was 13.4 per 1000 (95% confidence intervals (95% CI) 11.44, 15.36) compared with 17.22 per 1000 (95% CI 15.51, 18.92) in the most deprived. For women the prevalence was 10.84 per 1000 (95% CI 9.00, 12.69) compared with 15.48 per 1000 (95% CI 13.84, 17.11) in the most deprived. The increased prevalence of diabetes in the most deprived areas was accounted for by increased prevalence of type 2 diabetes in the age band 40-69 years. There was no association between the prevalence of type 1 diabetes and socioeconomic status. CONCLUSION: These data confirm an inverse association between socioeconomic status and the prevalence of type 2 diabetes in the middle years of life. This finding suggests that exposure to factors that are implicated in the causation of diabetes is more common in deprived areas.     

Sensory neural processing in work-related upper limb disorders

Pain in the upper limb is a common complaint in adults, and is often attributed to or exacerbated by occupational activities. In many patients there is no demonstrable pathology in the neck or arm to account for the symptom, and this has prompted the hypothesis that such cases might arise through abnormal neural processing of sensory information with a lowering of pain thresholds. In this paper we review the evidence in support of this theory and suggest directions for future research.     

A study of P2X1 receptor function in murine megakaryocytes and human platelets reveals synergy with P2Y receptors

We have examined the role of ATP-dependent P2X(1) receptors in megakaryocytes (MKs) and platelets using receptor-deficient mice and selective agonists. Alpha,beta-meATP- and ATP- evoked ionotropic inward currents were absent in whole-cell recordings from MKs of P2X(1)(-/-) mice, demonstrating that the P2X receptor phenotype in MKs, and by inference, platelets, is due to expression of homomeric P2X(1) receptors. P2X(1) receptor deficiency had no effect on MK (CD 41) numbers or size distribution, showing that it is not essential for normal MK development. P2Y receptor-stimulated [Ca(2+)](i) responses were unaffected in MKs from P2X(1)(-/-) mice, however the inward cation current associated with Ca(2+) release was reduced by approximately 50%, suggesting an interaction between the membrane conductances activated by P2X(1) and P2Y receptors. Interaction between P2X(1) and P2Y receptors in human platelets was also examined using [Ca(2+)](i) recordings from cell suspensions. Alpha,beta-meATP (10 microM) evoked a rapid transient P2X(1) receptor-mediated increase in [Ca(2+)](i), whereas ADP-(10 microM) evoked P2Y receptor responses were slower, peaked at a higher level and remained elevated for longer periods. Co-application of alpha, beta-meATP and ADP resulted in marked acceleration and amplification of the peak [Ca(2+)](i) response. We conclude that ionotropic P2X(1) receptors may play a priming role in the subsequent activation of metabotropic P2Y receptors during platelet stimulation.