Nanofibrous structured biomimetic strategies for skin tissue regeneration

Mimicking porous topography of natural extracellular matrix is advantageous for successful regeneration of damaged tissues or organs. Nanotechnology being one of the most promising and growing technology today shows an extremely huge potential in the field of tissue engineering. Nanofibrous structures that mimic the native extracellular matrix and promote the adhesion of various cells are being developed as tissue‐engineered scaffolds for skin, bone, vasculature, heart, cornea, nervous system, and other tissues. A range of novel biocomposite materials has been developed to enhance the bioactive or therapeutic properties of these nanofibrous scaffolds via surface modifications, including the immobilization of functional cell‐adhesive ligands and bioactive molecules such as drugs, enzymes, and cytokines. In skin tissue engineering, usage of allogeneic skin is avoided to reestablish physiological continuity and also to address the challenge of curing acute and chronic wounds, which remains as the area of exploration with various biomimetic approaches. Two‐dimensional, three‐dimensional scaffolds and stem cells are presently used as dermal regeneration templates for the treatment of full‐thickness skin defects resulting from injuries and severe burns. The present review elaborates specifically on the fabrication of nanofibrous structured strategies for wound dressings, wound healing, and controlled release of growth factors for skin tissue regeneration.     

“Artifactual fracture-subluxation” of cervical spine in computed tomography screening sans plain radiographs

Background contextComputed tomography (CT) has become the sole modality of screening for cervical injury in polytrauma because of the high sensitivity, speed, and convenience, thereby eliminating the need for plain radiographs.PurposeWe report two cases of misleading artifactual fracture-subluxation of cervical spine in CT, which could have resulted in needless treatment, and describe its characteristics.Study designCase report and review.MethodsTwo patients who were initially diagnosed with fracture-subluxation on screening CT cervical spine were later noted to have motion artifacts and were reviewed.ResultsThe artifactual nature of the supposed fracture-subluxation was unmasked by the soft-tissue findings of obscuration in sagittal reconstruction and duplication in axial images, along with the presence of double bony margins.ConclusionsMotion artifact in cervical CT screening can lead to a misdiagnosis of fracture subluxation. Duplication of soft tissue is highly suggestive of this motion artifact, and an additional single lateral plain radiograph may avert this pitfall.     

PET imaging of acetylcholinesterase inhibitor‐induced effects on α4β2 nicotinic acetylcholine receptor binding

Acetylcholinesterase inhibitors (AChEIs) are drugs that increase synaptic acetylcholine (ACh) concentrations and are under investigation as treatments for symptoms accompanying Alzheimer's disease. The goal of this work was to use PET imaging to evaluate alterations of in vivo α4β2 nicotinic acetylcholine receptor (nAChR) binding induced by the AChEIs physostigmine (PHY) and galanthamine (GAL). The α4β2 nAChR‐specific radioligand [¹⁸F]nifene was used to examine the effects of 0.1–0.2 mg/kg PHY, 5 mg/kg GAL, and saline in three separate experiments all performed on each of two rat subjects. A 60‐min bolus‐infusion protocol was used with drug administered after 30 min. Data from the thalamus and cortex were analyzed with a graphical model accounting for neurotransmitter activation using the cerebellum as a reference region to test for transient competition with bound [¹⁸F]nifene. Significant [¹⁸F]nifene displacement was detected in both regions during one PHY and both GAL studies, while no significant competition was observed in both saline studies. This preliminary work indicates the viability of [¹⁸F]nifene in detecting increases in synaptic ACh induced by AChEIs. Synapse 67:882–886, 2013. © 2013 Wiley Periodicals, Inc.     

Laccase production by the white-rot fungus Termitomyces clypeatus

Laccase was detected in the culture filtrate of white-rot fungus Termitomyces clypeatus. The enzyme was found at the late phase of submerged growth in a medium containing glucose or cellulose as the carbon source. The present study indicates that laccase produced by T. clypeatus is an intracellular enzyme, released in the medium due to cell lysis at the end of the growing phase. Laccase produced by T. clypeatus is different from the extracellular polyphenol oxidase of T. albuminosus, also produced at the late phase of growth. This is the first report of laccase production by a Termitomyces sp.     

Porin of Shigella dysenteriae activates mouse peritoneal macrophage through Toll-like receptors 2 and 6 to induce polarized type I response

Porin of Shigella dysenteriae type 1 coexpressed Toll-like receptor (TLR) 2 and TLR6 on peritoneal cavity (PerC) macrophages (MPhi) of C57BL/6 mice implicating that both the TLRs are essential as a combinatorial repertoire to recognize the protein. Besides TLRs, mRNA for MyD88 and TRAF6, and nuclear translocation of NF-kappaB were enhanced that indicate their involvement in tandem in the activity of porin. The protein selectively up-regulated CD80 on the activated MPhi together with MHC class II molecule and CD40, and had no effect on CD86 expression. The porin-induced profile of MIP-1alpha, MIP-1beta and RANTES showed strong bias for chemokines correlated with M1 polarization. Intracellular expression and release of TNF-alpha and IL-12 in presence of porin was found to be TLR2 and NF-kappaB dependent. Induction of TNF-alpha and IL-12 along with the chemokine profile suggests type I polarization of the MPhi that would influence Th1-type response.     

Improving estimation and prediction in linear regression incorporating external information from an established reduced model

We consider a situation where there is rich historical data available for the coefficients and their standard errors in a linear regression model describing the association between a continuous outcome variable Y and a set of predicting factors X , from a large study. We would like to use this summary information for improving inference in an expanded model of interest, Y given X , B . The additional variable B is a new biomarker, measured on a small number of subjects in a new dataset. We formulate the problem in an inferential framework where the historical information is translated in terms of nonlinear constraints on the parameter space and propose both frequentist and Bayes solutions to this problem. We show that a Bayesian transformation approach proposed by Gunn and Dunson is a simple and effective computational method to conduct approximate Bayesian inference for this constrained parameter problem. The simulation results comparing these methods indicate that historical information on E( Y | X ) can improve the efficiency of estimation and enhance the predictive power in the regression model of interest E( Y | X , B ). We illustrate our methodology by enhancing a published prediction model for bone lead levels in terms of blood lead and other covariates, with a new biomarker defined through a genetic risk score.