Setlow P.,UCONN Health |
Li L.,Indiana University - Purdue University Indianapolis |
Li L.,Indiana University
Photochemistry and Photobiology | Year: 2015
Fifty years ago, a new thymine dimer was discovered as the dominant DNA photolesion in UV-irradiated bacterial spores [Donnellan, J. E. & Setlow R. B. (1965) Science, 149, 308-310], which was later named the spore photoproduct (SP). Formation of SP is due to the unique environment in the spore core that features low hydration levels favoring an A-DNA conformation, high levels of calcium dipicolinate that acts as a photosensitizer, and DNA saturation with small, acid-soluble proteins that alters DNA structure and reduces side reactions. In vitro studies reveal that any of these factors alone can promote SP formation; however, SP formation is usually accompanied by the production of other DNA photolesions. Therefore, the nearly exclusive SP formation in spores is due to the combined effects of these three factors. Spore photoproduct photoreaction is proved to occur via a unique H-atom transfer mechanism between the two involved thymine residues. Successful incorporation of SP into an oligonucleotide has been achieved via organic synthesis, which enables structural studies that reveal minor conformational changes in the SP-containing DNA. Here, we review the progress on SP photochemistry and photobiology in the past 50 years, which indicates a very rich SP photobiology that may exist beyond endospores. © 2015 The American Society of Photobiology.
Parham K.,UCONN Health
Medical Hypotheses | Year: 2015
Acquired sensorineural hearing loss and tinnitus can come about through various etiologies such as exposure to excessively loud noise or drugs with ototoxic properties. As such, acquired hearing loss is a common source of morbidity which deleteriously affects the ability to communicate. At present our ability to detect acquired hearing loss and tinnitus at its earliest stages is limited and there are no adjuncts to audiometric evaluation. The earliest cellular targets of noise and ototoxins in the cochlea are the outer hair cells (OHC). I hypothesize that serum assays of OHC specific protein, prestin, will allow detection and quantification of OHC damage before audiometric testing can identify presence of hearing loss. At present, there are no data available to evaluate this hypothesis, but initial evaluation can readily be carried out using existing experimental animal models of ototoxicity and noise-induced hearing loss. Early detection of OHC damage is critical to adoption of measures aimed at ameliorating hearing loss and tinnitus, thus reducing permanent deficits and disability. © 2015 Elsevier Ltd.
Denry I.,University of Iowa |
Kuhn L.T.,UCONN Health
Dental Materials | Year: 2016
Objectives Our goal is to review design strategies for the fabrication of calcium phosphate ceramic scaffolds (CPS), in light of their transient role in bone tissue engineering and associated requirements for effective bone regeneration. Methods We examine the various design options available to meet mechanical and biological requirements of CPS and later focus on the importance of proper characterization of CPS in terms of architecture, mechanical properties and time-sensitive properties such as biodegradability. Finally, relationships between in vitro versus in vivo testing are addressed, with an attempt to highlight reliable performance predictors. Results A combinatory design strategy should be used with CPS, taking into consideration 3D architecture, adequate surface chemistry and topography, all of which are needed to promote bone formation. CPS represent the media of choice for delivery of osteogenic factors and anti-infectives. Non-osteoblast mediated mineral deposition can confound in vitro osteogenesis testing of CPS and therefore the expression of a variety of proteins or genes including collagen type I, bone sialoprotein and osteocalcin should be confirmed in addition to increased mineral content. Conclusions CPS are a superior scaffold material for bone regeneration because they actively promote osteogenesis. Biodegradability of CPS via calcium and phosphate release represents a unique asset. Structural control of CPS at the macro, micro and nanoscale and their combination with cells and polymeric materials is likely to lead to significant developments in bone tissue engineering. © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
Stern A.S.,Rowland Institute at Harvard |
Hoch J.C.,UCONN Health
Magnetic Resonance in Chemistry | Year: 2015
Compressed sensing (CS) has attracted a great deal of recent interest as an approach for spectrum analysis of nonuniformly sampled NMR data. Although theoretical justification for the method is abundant, it suffers from several weaknesses, among them poor convergence of some algorithms, and it remains an open question whether NMR spectra satisfy the sparsity requirements of CS theorems. The versions of CS used in NMR involve minimizing the l1 norm of the spectrum. They bear similarity to maximum entropy (MaxEnt) reconstruction, but critical comparison of the methods can be difficult. Here we describe a formalism that places CS and MaxEnt reconstruction on equal footing, enabling critical comparison of the two methods. We also describe a new algorithm for CS that restricts the computation of the l1 norm to the real channel for complex spectra and ensures causality. Preliminary 1D results demonstrate that this approach ameliorates some artifacts that can occur when using the l1 norm of the complex spectrum. © 2015 John Wiley & Sons, Ltd.
DeBerardino T.M.,UCONN Health
Sports Medicine and Arthroscopy Review | Year: 2015
Regenerative medicine technology is currently being used to create hyaline-like cartilage tissue from autologous cartilage cells. NeoCart is one such investigational scaffold-based cartilage implant used to treat knee cartilage injuries. There are limited data available regarding this specific treatment option, as NeoCart is currently undergoing a phase III clinical trial at several cartilage restoration centers across the United States. © 2015 Wolters Kluwer Health, Inc.