Silk Fibroin as a Green Material.

Silk fibroin has been explored as a suitable biomaterial due to its biocompatibility, tunable degradability, low toxicity, and mechanical properties. To harness silk fibroin's innate properties, it is purified from native silkworm cocoons by removing proteins and debris that have the potential to cause inflammatory responses. Typically, within the purification and fabrication steps, chemical solvents, energy-intensive equipment, and large quantities of water are used to reverse engineer silk fibroin into an aqueous solution and then process into the final material format. Gentler, green methods for extraction and fabrication have been developed that reduce or remove the need for harmful chemical additives and energy-inefficient equipment while still producing mechanically robust biomaterials. This review will focus on the alternative green processing and fabrication methods that have proven useful in creating silk fibroin materials for a range of applications including consumer and medical materials.

Changes in Physician Decision Making after CT: A Prospective Multicenter Study in Primary Care Settings.

Purpose To determine the effect of computed tomography (CT) results on physician decision making in three common clinical scenarios in primary care. Materials and Methods This research was approved by the institutional review board (IRB) and was HIPAA compliant. All physicians consented to participate with an opt-in or opt-out mechanism; patient consent was waived with IRB approval. In this prospective multicenter observational study, outpatients referred by primary care providers (PCPs) for CT evaluation of abdominal pain, hematuria, or weight loss were identified. Prior to CT, PCPs were surveyed to elicit their leading diagnosis, confidence in that diagnosis (confidence range, 0%-100%), a rule-out diagnosis, and a management plan if CT were not available. Surveys were repeated after CT. Study measures were the proportion of patients in whom leading diagnoses and management changed (PCP management vs specialist referral vs emergency department transfer), median changes in diagnostic confidence, and the proportion of patients in whom CT addressed rule-out diagnoses. Regression analyses were used to identify associations between study measures and site and participant characteristics. Specifically, logistic regression analysis was used for binary study measures (change in leading diagnosis, change in management), and linear regression analysis was used for the continuous study measure (change in diagnostic confidence). Accrual began on September 5, 2012, and ended on June 28, 2014. Results In total, 91 PCPs completed pre- and post-CT surveys in 373 patients. In patients with abdominal pain, hematuria, or weight loss, leading diagnoses changed after CT in 53% (131 of 246), 49% (36 of 73), and 57% (27 of 47) of patients, respectively. Management changed in 35% (86 of 248), 27% (20 of 74), and 54% (26 of 48) of patients, respectively. Median absolute changes in diagnostic confidence were substantial and significant (+20%, +20%, and +19%, respectively; P ≤ .001 for all); median confidence after CT was high (90%, 88%, and 80%, respectively). PCPs reported CT was helpful in confirming or excluding rule-out diagnoses in 98% (184 of 187), 97% (59 of 61), and 97% (33 of 34) of patients, respectively. Significant associations between primary measures and site and participant characteristics were not identified. Conclusion Changes in PCP leading diagnoses and management after CT were common, and diagnostic confidence increased substantially. © RSNA, 2016 Online supplemental material is available for this article.

Structured feedback from referring physicians: a novel approach to quality improvement in radiology reporting.

OBJECTIVE: There is considerable interest in improving radiology reporting practices through peer review, and the inclusion of structured feedback from referring physicians may improve this process. The purpose of this article is to evaluate the feasibility of this type of novel peer-review system. MATERIALS AND METHODS: Five referring physicians from our institution participated as reviewers. Reports from abdominal CT, chest CT, brain MRI, and abdominal ultrasound were eligible for review if the indication was "abdominal pain," "shortness of breath," "headache," and "pain," respectively. Reports were excluded if the examinations were normal or ordered as follow-up. Forty-eight reports (12 from each group) were then selected at random and distributed to the referring physicians along with the clinical scenario and an evaluation form for each examination. RESULTS: The reports were found to be clinically useful (average, 3.8 on a 1-5 scale), allowing for good confidence in clinical decision making (average, 3.7). The most common problems were unclear language, typographical errors, and reports that did not answer the clinical question. Of the reports, 35.4% contained recommendations for further diagnosis or treatment, and 84.7% of these recommendations were deemed clinically appropriate. The participating physicians thought that the results of 31.2% of the examinations should have been directly communicated to the ordering provider. CONCLUSION: Radiology reports and recommendations were clinically useful, even though problems with language, typographical errors, answering the clinical question, and direct communication of examination results were identified. Structured feedback from referring physicians is a novel approach to the peer-review process that may identify problems that go unnoticed by the radiologist, thereby improving reporting practices.

Human macrophage response to UHMWPE, TiAlV, CoCr, and alumina particles: analysis of multiple cytokines using protein arrays.

Aseptic loosening of total joint replacements is believed to be initiated by a macrophage response to prosthetic wear debris. To better characterize the early response to clinically relevant wear debris, we challenged primary human macrophages from four donors with ultra high molecular weight polyethylene (UHMWPE), TiAlV, CoCr, and alumina particles. After a 24-h culture, protein arrays were used to quantify the secretion of 30 different cytokines and chemokines. Macrophages secreted detectable levels of nine mediators in culture: Interleukin-1alpha (IL-1alpha), tumor necrosis factor-alpha (TNF-alpha), IL-1beta, MCP-1, IL-8, IL-6, GM-CSF, IL-10, and IL-12p40. TiAlV particles were the most stimulatory, causing 5- to 900-fold higher cytokine expression compared with nonstimulated cells and uniquely eliciting high levels of IL-1alpha, IL-6, IL-10, and GM-CSF. CoCr and alumina were mildly stimulatory and typically elicited two- to fivefold greater levels than nonstimulated cells. Surprisingly, UHMWPE did not elicit a significant increase in cytokine release. Our data suggests that IL-1alpha, TNF-alpha, IL-1beta, and MCP-1 are the primary initiators of osteolysis and implicates metallic debris as an important trigger for their release.

Arterio-venous fistula: two cases realistic numerical blood flow simulations.

Patients with ESRD "End-stage renal disease" require hemodialysis. The most desirable form of vascular access is the arterio-venous fistula (AVF). It is placed surgically joining an artery and a vein together. We propose an investigation protocol to understand the correlation between hemodynamics in this vessel and the associated clinical complications. Realistic 3D reconstruction of the fistula is the result of segmenting CT angiography images for two cases. Then the geometrical model is preprocessed by hybrid meshing and CFD results are confronted with medical image data such as calcifications.

Anabolic effects of bisphosphonates on peri-implant bone stock.

The long-term durability of total joint replacements is critically dependent on adequate peri-implant bone stock, which can be compromised by wear debris-mediated osteolysis. This study investigated the effects of bisphosphonates on enhancing peri-implant bone in the presence of clinically relevant ultra-high molecular weight polyethylene (UHMWPE) wear debris. Fiber-mesh coated titanium-alloy plugs were implanted bilaterally in the femoral condyles of 36 New Zealand white rabbits. Implants in the left femora were covered with submicron UHMWPE particles during surgery. Rabbits were administered either no drug, subcutaneous alendronate weekly (1.0mg/kg/week) or a single dose of intravenous zoledronate (0.015mg/kg). A total of 6/12 rabbits in each group were sacrificed at 6 weeks and the remainder at 12 weeks postoperatively. Peri-implant bone stock was analyzed radiographically and histomorphometrically. Radiographically, both bisphosphonates significantly increased periprosthetic cortical thickness at 6 weeks (p<0.0001; alendronate: +18%; zoledronate: +11%) and at 12 weeks (p=0.001; alendronate: +17%; zoledronate:+19%). Histomorphometrically, alendronate and zoledronate raised peri-implant bone volume (BV/TV) up to 2-fold after 6 weeks without added wear debris and more than 3-fold when wear debris was present. Furthermore a 6-week bisphosphonate treatment increased osteoid thickness in the absence of wear debris (alendronate: +132%, p=0.007; zoledronate: +67%, p=0.51) and in the presence of wear debris (alendronate: +134%, p=0.023; zoledronate: +138%, p=0.016). In summary, alendronate and zoledronate treatment increased periprosthetic bone stock in a rabbit femoral model, particularly in the presence of UHMWPE wear debris. These new findings suggest that bisphosphonates may more than compensate for the well-documented negative effects of wear debris on peri-implant bone stock. The combined antiresorptive and osteoanabolic effects of bisphosphonates on periprosthetic bone stock may have an important role for critically improving the biological fixation and ultimate durability of total joint arthroplasty.

Investigations into the relationship between hemodynamics and vascular alterations in an established arteriovenous fistula.

Arteriovenous fistula are specific vessels created by a vascular operation in order to provide sufficient blood access for extracorporeal circulation in hemodialysis. They are subject to numerous pathologies that may be caused by hemodynamic effects. To better understand these effects, a specific patient's arteriovenous fistula was reconstructed from computed tomography angiography. Computational fluid dynamics software made it possible to solve fluid mechanics equations under physiological conditions. An accurate map of unsteady velocity profiles and wall shear stress was drawn up. The computed velocity profiles were successfully confronted with Echo Doppler investigation. Selected regions with or without calcification, the end stage of wall alteration, were examined in terms of the mechanical constraints generated by blood flow. In contrast with other authors, we did not observe any association between calcification and areas of oscillating shear stress. Nevertheless, a statistical analysis of the whole vessel envelop and specific sites of calcification suggested a potential association between calcification and high temporal wall shear stress gradients.

Automated analysis of MR image of hip: geometrical evaluation of the Legg-Calve-Perthes disease.

This study proposes semi-automatic determination of geometrical features in hip magnetic resonance (MR) images in order to evaluate the Legg-Calvé-Perthes disease (LCPD). Nine anatomical points on a hip image are selected by a clinician; then eight geometrical indexes of the hip joint are calculated: acetabulum head index (AHI), Wiberg angle (VCE), inner acetabular coverage angle (VCI), acetabular inclination angle (HTE), femoral shaft-neck angle (CC'D), circularity (C), convex deficiency factor (CDF) and pillar height deficiency factor (HDF) for the head region. The geometrical parameters are evaluated on 46 hip images of young patients with unilateral LCPD: 23 images concern the affected hip and 23 the unaffected hip. The extraction of the region of interest is done with a seeded region growing method. All the data were centered and reduced, and were subjected to principal component analysis. Supervised classification is applied with discriminant analysis and k-nearest neighbours classification. The AHI appears to be the best discriminant attribute (maximum between-class variance ratio). Cross-validation tests indicate that we can at most reduce the parameters to five (AHI, CC'D, DHF, DCF and VCE). The classification error rate for the linear discriminant method is 12.5%.