Vascular Tissue Engineering Using Scaffold-Free Prevascular Endothelial-Fibroblast Constructs.

Vascularization remains a substantial limitation to the viability of engineered tissue. By comparing vascularization dynamics of a self-assembled prevascular endothelial-fibroblast model to avascular grafts, we explore the vascularization rate limitations in implants at early time intervals, during which tissue hypoxia begins to affect cell viability. Scaffold-free prevascular endothelial-fibroblast constructs (SPECs) may serve as a modular and reshapable vascular bed in replacement tissues.

Microdissection of Primary Renal Tissue Segments and Incorporation with Novel Scaffold-free Construct Technology.

Kidney transplantation is now a mainstream therapy for end-stage renal disease. However, with approximately 96,000 people on the waiting list and only one-fourth of these patients achieving transplantation, there is a dire need for alternatives for those with failing organs. In order to decrease the harmful consequences of dialysis along with the overall healthcare costs it incurs, active investigation is ongoing in search of alternative solutions to organ transplantation.

Mechanism of action of the anti-inflammatory connexin43 mimetic peptide JM2.

Connexin-based therapeutics have shown the potential for therapeutic efficacy in improving wound healing. Our previous work demonstrated that the connexin43 (Cx43) mimetic peptide juxtamembrane 2 (JM2) reduced the acute inflammatory response to a submuscular implant model by inhibiting purinergic signaling. Given the prospective application in improving tissue-engineered construct tolerance that these results indicated, we sought to determine the mechanism of action for JM2 in the present study.

Inhibition of connexin 43 hemichannel-mediated ATP release attenuates early inflammation during the foreign body response.

Background: In the last 50 years, the use of medical implants has increased dramatically. Failure of implanted devices and biomaterials is a significant source of morbidity and increasing healthcare expenditures. An important cause of implant failure is the host inflammatory response.

Predicting academic performance in surgical training.

Introduction: During surgical residency, trainees are expected to master all the 6 competencies specified by the ACGME. Surgical training programs are also evaluated, in part, by the residency review committee based on the percentage of graduates of the program who successfully complete the qualifying examination and the certification examination of the American Board of Surgery in the first attempt. Many program directors (PDs) use the American Board of Surgery In-Training Examination (ABSITE) as an indicator of future performance on the qualifying examination.

Purinergic signaling in early inflammatory events of the foreign body response: modulating extracellular ATP as an enabling technology for engineered implants and tissues.

Purinergic signaling is a ubiquitous and vital aspect of mammalian biology in which purines--mainly adenosine triphosphate (ATP)--are released from cells through loss of membrane integrity (cell death), exocytosis, or transport/diffusion across membrane channels, and exert paracrine or autocrine signaling effects through three subclasses of well-characterized receptors: the P1 adenosine receptors, the P2X ionotropic nucleotide receptors, and the P2Y metabotropic receptors. ATP and its metabolites are released by damaged and stressed cells in injured tissues. The early events of wound healing, hemostasis, and inflammation are highly regulated by these signals through activation of purinergic receptors on platelets and neutrophils.

A model system for primary abdominal closures.

The foreign body response to medical devices and materials implanted in the human body, including scarring, fibrous encapsulation, and potential rejection, is a longstanding and serious clinical issue. There are no widely acceptable or safe therapies for ameliorating the foreign body response. Clinical complications resulting from the response include disfigurement of silicone prostheses and loss of function of devices such as implanted pacemakers, stents, and shunts.

Determining personal talents and behavioral styles of applicants to surgical training: a new look at an old problem, part II.

Background: The selection of applicants for training in any particular surgical program is an imprecise exercise. Despite the abundance of information on particular candidates, many of the fundamental qualities that are associated with success for the surgical trainee cannot be identified by review of the applicants' grades, scores, letters of recommendation, personal statement, or even from the interview process. We sought a method to determine behavior, motivation, and values possessed by applicants that coincided with traits by our current residents who had demonstrated success in our program.

Determining personal talents and behavioral styles of applicants to surgical training: a new look at an old problem, part I.

Background: The selection of residents for any program and their evaluation for success is an inexact science. Errors can prove costly, disruptive, and potentially damaging to training programs, and personal and professional setbacks can occur for resident applicants. A method was sought to determine the intangible characteristics of applicants to a general surgery residency program, particularly an assessment of behavior and motivation.

Swallowing dysfunction in trauma patients with cervical spine fractures treated with halo-vest fixation.

Unlabelled: ACKGROUND:: Cervical spine fractures are common in traumatically injured patients. The halo-vest brace is a common treatment used for these fractures. We hypothesize that the use of halo-vest fixation is associated with a high incidence of dysphagia in trauma patients.

Human satellite progenitor cells for use in myofascial repair: isolation and characterization.

Current use of prosthetic meshes and implants for myofascial reconstruction has been associated with infectious complications, long-term failure, and dissatisfying cosmetic results. Our laboratory has developed a small animal model for ventral hernia repair, which uses progenitor cells isolated from a skeletal muscle biopsy. In the model, progenitor cells are expanded in vitro, seeded onto a nonimmunogenic, novel aligned scaffold of bovine collagen and placed into the defect as a living adjuvant to the innate repair mechanism.

Novel bacterial immobilization compound effectively decreases bacterial counts in healthy volunteers.

Skin flora immobilization technology is similar in efficacy to Iodine-Povidone in healthy volunteers. We did a prospective study in a university clinic with 60 healthy volunteers. Right inguinal skin area on healthy volunteers was used to compare the antimicrobial properties of cyanoacrylate sealant (FloraSeal, Adhesion Biomedical, Wyomissing, PA) versus standard surgical preparation Povidone-iodine (Betadine, Purdue Productions, Stamford, CT).

Focused in vivo genetic analysis of implanted engineered myofascial constructs.

Successfully engineering functional muscle tissue either in vitro or in vivo to treat muscle defects rather than using the host muscle transfer would be revolutionary. Tissue engineering is on the cutting edge of biomedical research, bridging a gap between the clinic and the bench top. A new focus on skeletal muscle tissue engineering has led investigators to explore the application of satellite cells (autologous muscle precursor cells) as a vehicle for engineering tissues either in vitro or in vivo.

Nanomechanical characterization of micro/nanofiber reinforced type I collagens.

To function properly in the rigorous tissue environment, implanted scaffolds for tissue engineering are required to meet certain standards of strength and mechanical integrity. However, the soft nature and moisture condition of biomaterials impose great challenges to many existing techniques and instrumentations for measuring their mechanical properties at micro/nano scale. In this work, we demonstrate the testing methodologies of micro/nano fiber reinforced type I collagens, and obtain basic mechanical property data of two types of modified collagens-micro carbon fiber reinforced collagen (MCFR) and nano collagen fiber reinforced collagen (NCFR).

The use of prognostic indicators in the development of a statistical model predictive for adrenal insufficiency in trauma patients.

We performed a retrospective chart review of trauma patients admitted to Palmetto Richland Memorial Hospital and identified 63 cases of adrenal insufficiency along with 65 trauma patient controls. Two statistical models, a neural network and a multiple logistic regression, were developed to predict patients with increased risk of developing adrenal insufficiency. Each model had 11 selected independent variables, along with patient demographic data, to make a probabilistic prediction of patient outcome.

A model of tissue-engineered ventral hernia repair.

We have developed a tissue-engineered ventral hernia repair system using our novel aligned collagen tube and autologous skeletal muscle satellite cells. In this model system, skeletal muscle satellite cells were isolated from a biopsy, expanded in culture, and incorporated into our collagen tube scaffold, forming the tissue-engineered construct. We characterized the results of the repaired hernias on both the gross and microscopic scales and compared them to an unrepaired control, an autologous muscle repair control, and a collagen-tube-only repair.

What is the future of diabetic wound care?

With diabetes affecting 5% to 10% of the US population, development of a more effective treatment for chronic diabetic wounds is imperative. Clinically, the current treatment in topical wound management includes debridement, topical antibiotics, and a state-of-the-art topical dressing. State-of-the-art dressings are a multi-layer system that can include a collagen cellulose substrate, neonatal foreskin fibroblasts, growth factor containing cream, and a silicone sheet covering for moisture control.