Biomimetic Approach to Perforation Repair Using Dental Pulp Stem Cells and Dentin Matrix Protein 1

Introduction

Dentin regeneration could be an ideal treatment option to restore tissue function. This study was conducted to evaluate the ability of dental pulp stem cells (DPSCs) and dentin matrix protein 1 (DMP1) impregnated within a collagen scaffold to regenerate dentin.

Methods

Simulated perforations were created in 18 dentin wafers made from freshly extracted human molars. Six groups were established. They were (1) empty wafers, (2) mineral trioxide aggregate, (3) collagen scaffold, (4) scaffold with DMP1, (5) scaffold with DPSCs, and (6) scaffold with DPSCs and DMP1. One sample was placed subcutaneously in each mouse with three mice in each group. After 12 weeks, the samples were subjected to radiographic, histological, and immunohistochemical evaluations.

Results

DPSCs impregnated within a collagen scaffold differentiated into odontoblast-like cells forming a highly cellular, vascular, and mineralized matrix in the presence of DMP1.

Conclusions

A triad consisting of DPSCs, DMP1, and a collagen scaffold promotes dentin regeneration in a simulated perforation repair model.     

Antimicrobial effect of triclosan and triclosan with Gantrez on five common endodontic pathogens

Microbial control of the root canal system is one of the key objectives of root canal therapy. Triclosan is a widely accepted broad spectrum antimicrobial agent proven to be effective against many gram-positive and gram-negative bacteria. Triclosan acts by blocking bacterial fatty acid biosynthesis. The addition of Gantrez copolymer has been shown to enhance the antimicrobial activity of triclosan. The purpose of this study was to determine the minimum inhibitory and bactericidal concentrations of triclosan and triclosan with Gantrez against Prevotella intermedia, Fusobacterium nucleatum, Actinomyces naeslundii, Porphyromonas gingivalis, and Enterococcus faecalis. The minimum inhibitory concentration (MIC) of both test solutions was determined for each of the 5 microorganisms by using microtiter serial dilutions. Samples were streaked on 5% sheep blood agar plates and placed in an anaerobic incubator to determine the minimum bactericidal concentration (MBC). The MBC of triclosan ranged from 12-94 microg/mL. The MBC of triclosan with Gantrez ranged from <0.3-10.4 microg/mL. The addition of Gantrez enhanced the bactericidal activity of triclosan. Both triclosan and triclosan with Gantrez demonstrated bactericidal activity against the 5 specific endodontic pathogens.     

Trained immunity in organ transplantation

Consistent induction of donor‐specific unresponsiveness in the absence of continuous immunosuppressive therapy and toxic effects remains a difficult task in clinical organ transplantation. Transplant immunologists have developed numerous experimental treatments that target antigen‐presentation (signal 1), costimulation (signal 2), and cytokine production (signal 3) to establish transplantation tolerance. While promising results have been obtained using therapeutic approaches that predominantly target the adaptive immune response, the long‐term graft survival rates remain suboptimal. This suggests the existence of unrecognized allograft rejection mechanisms that contribute to organ failure. We postulate that trained immunity stimulatory pathways are critical to the immune response that mediates graft loss. Trained immunity is a recently discovered functional program of the innate immune system, which is characterized by nonpermanent epigenetic and metabolic reprogramming of macrophages. Since trained macrophages upregulate costimulatory molecules (signal 2) and produce pro‐inflammatory cytokines (signal 3), they contribute to potent graft reactive immune responses and organ transplant rejection. In this review, we summarize the detrimental effects of trained immunity in the context of organ transplantation and describe pathways that induce macrophage training associated with graft rejection.     

Magnetic resonance imaging of atherosclerosis by targeting extracellular matrix deposition with Gadofluorine M

As previously reported, Gadofluorine M‐enhanced magnetic resonance imaging clearly demarcates atherosclerotic plaques from the normal vessel wall. To date, the underlying mechanism has remained unknown. Gadofluorine M is a gadolinium‐containing macrocyclic contrast agent containing hydrophilic and hydrophobic moieties. To elucidate the mechanism of accumulation, fluorescently labeled and radioactively labeled derivates of Gadofluorine M were used to determine affinity and specificity of Gadofluorine M binding to blood serum and plaque components in vitro and for the distribution within the plaque of WHHL rabbits in vivo. Gadofluorine M binds to serum albumin, leading to a breakdown of micelles after intravenous injection. The affinity of Gadofluorine M to serum albumin is k_D = 2 µmol/l. Gadofluorine then penetrates the atherosclerotic plaque while bound to albumin and then accumulates within the extracellular, fibrous parts of the plaque by binding to collagens, proteoglycans and tenascin, having the same affinity to these plaque constituents as to albumin. In contrast, weak binding was determined to LDL (k_D = 2 mmol/l) and even no binding to hyaluronic acid. The driving force of binding and accumulation is the hydrophobic moiety of the molecules interacting with hydrophobic plaque materials. Thus, Gadofluorine M accumulates within the fibrous plaque or in the fibrous cap of a plaque containing high amounts of extracellular matrix components, but not in the lipid‐rich areas. In combination with high‐resolution MRI, Gadofluorine M might enable the detection of thin‐cap fibroatheromas, also named the vulnerable plaque. Copyright © 2007 John Wiley & Sons, Ltd.     

COMMUNITY PSYCHOLOGY AND CIVIL SOCIETY: OPPORTUNITIES FOR GROWTH IN EGYPT AND LEBANON

Western theories and products, focused mostly on the individual level of analysis, inform psychology in Egypt and Lebanon. Psychologists in these nations have not yet played a significant role in addressing systemic community priorities, such as poverty and politically motivated violence. In the absence of community psychology, a vibrant network of civil society organizations has emerged to address urgent national concerns. We discuss and critique three types of civil society efforts that intersect with community psychology values and practice: community development, refugee services, and human rights advocacy. The emerging specialization of community psychology can address limitations of these fields and provide an alternative psychological perspective to community practice. This article examines how Egyptian and Lebanese community psychologies may transpire, including the roles community psychologists can play, values that may be integrated in this work, and considerations for formalizing training programs.     

Atherosclerotic plaque imaging: contemporary role in preventive cardiology

Coronary artery disease imaging has traditionally been based on luminal angiography, but it has become evident that this tool, although extremely useful in diagnosing obstructive disease, is insufficient to define the presence and extent of atherosclerotic disease in the vessel wall. Progression of coronary artery disease was also initially evaluated using quantitative coronary angiography, and evidence soon accumulated that minor regression or nonprogression of luminal disease was associated with a favorable cardiovascular outcome. In recent years, however, several other techniques have been developed to image atherosclerosis and are emerging as useful tools in preventive cardiovascular medicine. These techniques provide new methods to assess the burden of atherosclerosis, gauge the risk of cardiovascular events, and offer a means to test the efficacy of therapeutic approaches to atherosclerosis. Furthermore, noninvasive coronary angiography can be performed with some of the new imaging modalities, potentially reducing the number of unnecessary invasive tests. This review focuses on techniques such as cardiac computed tomography, carotid artery intima-media thickness, cardiovascular magnetic resonance imaging, and intravascular ultrasonography as emerging tools in cardiovascular disease prevention.     

Efficacy of different doses of sugammadex after continuous infusion of rocuronium

AIM: To evaluate the effects of two different doses of sugammadex after maintenance anesthesia with sevofluorane and remifentanil and deep rocuroniuminduced neuromuscular blockade(NMB).METHODS: Patients between 20 and 65 years of age, with American Society of Anesthesiologists physical status classification Ⅰ-Ⅱ, undergoing gynecological surgery were included in a prospective, comparative and randomized study. NMB was induced with an injection of 0.6 mg/kg of rocuronium followed by continuous infusion of 0.3-0.6 mg/kg per hour to maintain a deep block. Anesthesia was maintained with sevofluorane and remifentanil. Finally, when surgery was finished, a bolus of 2 mg/kg(group A) or 4 mg/kg(group B) of sugammadex was applied when the NMB first response in the train-of-four was reached. The primary clinical endpoint was time to recovery to a train-of-four ratio of 0.9. Other variables recorded were the time until recovery of train-of-four ratio of 0.7, 0.8, hemodynamic variables(arterial blood pressure and heart rate at baseline, starting sugammadex, and minutes 2, 5 and 10) and adverse events were presented after one hour in the post-anesthesia care unit.RESULTS: Thirty-two patients were included in the study: 16 patients in group A and 16 patients in group B. Only 14 patients each group were recorded because arterial pressure values were lost in two patients from each group in minute 10. The two groups were comparable. Median recovery time from starting of sugammadex administration to a train-of-four ratio of 0.9 in group A and B was 129 and 110 s, respectively.The estimated difference in recovery time between groups was 24 s(95%CI: 0 to 45 s, Hodges-Lehmann estimator), entirely within the predefined equivalence interval. Times to recovery to train-of-four ratios of 0.8(group A: 101 s; group B: 82.5 s) and 0.7(group A: 90 s; group B: 65 s) from start of sugammadex administration were not equivalent between groups. There was not a significant variation in the arterial pressure and heart rate values between the two groups and none of the patients showed any clinical evidence of residual or recurrent NMB. CONCLUSION: A dose of 2 mg/kg of sugammadex after continuous rocuronium infusion is enough to reverse the NMB when first response in the Train-OfFour is reached.