Temple University

About: Temple University is a education organization based out in Philadelphia, Pennsylvania, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 32154 authors who have published 64375 publications receiving 2219828 citations.

Regression of Cellular Hypertrophy After Left Ventricular Assist Device Support

Abstract: Background —Although multiple studies have shown that the left ventricular assist device (LVAD) improves distorted cardiac geometry, the pathological mechanisms of the “reverse remodeling” of the heart are unknown. Our goal was to determine the effects of LVAD support on cardiac myocyte size and shape. Methods and Results —Isolated myocytes were obtained at cardiac transplantation from 30 failing hearts (12 ischemic, 18 nonischemic) without LVAD support, 10 failing hearts that received LVAD support for 75±15 days, and 6 nonfailing hearts. Cardiac myocyte volume, length, width, and thickness were determined by use of previously validated techniques. Isolated myocytes from myopathic hearts exhibited increased volume, length, width, and length-to-thickness ratio compared with normal myocytes ( P <0.05). However, there were no differences in any parameter between myocytes from ischemic and nonischemic cardiomyopathic hearts. Long-term LVAD support resulted in a 28% reduction in myocyte volume, 20% reduction in cell length, 20% reduction in cell width, and 32% reduction in cell length-to-thickness ratio ( P <0.05). In contrast, LVAD support was associated with no change in cell thickness. These cellular changes were associated with reductions in left ventricular dilation and left ventricular mass measured echocardiographically in 6 of 10 LVAD-supported patients. Conclusions —These studies suggest that the regression of cellular hypertrophy is a major contributor to the “reverse remodeling” of the heart after LVAD implantation. The favorable alterations in geometry that occur in parallel fashion at both the organ and cellular levels may contribute to reduced wall stress and improved mechanical performance after LVAD support.

Identification and functions of usefully disordered proteins.

Abstract: Publisher Summary This chapter illustrates that protein disorder is encoded by the amino acid sequence and that protein disorder is essential for many important biological functions. An ordered protein contains a single canonical set of Ramachandran angles, whereas a disordered protein or region contains an ensemble of divergent angles at any instant and these angles interconvert over time. Intrinsically disordered protein can be extended (random coil–like) or collapsed (molten globule–like). The latter type of disorder typically includes regions of fluctuating secondary structure, so disorder does not mean absence of helix or sheet. Both types of disorders have been observed in apparently native proteins. Intrinsic disorder might not be encoded by the sequence, but rather might be the result of the absence of suitable tertiary interactions. If this were the general cause of intrinsic disorder, any subset of ordered sequences and any subset of disordered sequences would likely be the same within the statistical uncertainty of the sampling. On the other hand, if intrinsic disorders were encoded by the amino acid sequence, any subset of disordered sequences would likely differ significantly from samples of ordered protein sequences.

A cognitive behavioral model of social anxiety disorder: update and extension

Abstract: Publisher Summary This chapter focuses on the original 1997 cognitive behavioral model for social anxiety disorder (SAD), which delineates the processes by which SAIs are affected by their fear of negative evaluation in potentially social-evaluative situations. The original model has provided a solid framework for understanding the factors that comprise and maintain SAD. Since the publication of Rapee and Heimberg (1997), updates are provided in the form of reviews of the literature that support various aspects of the model, applied the model to a case study of a person with SAD, and conducted a comparison between the model and the very influential and productive model proposed by Clark and Wells. Given that there has been over a decade of intervening research, however, there are areas in the model that warrant expansion, as well as additional factors that necessitate inclusion in the model. The chapter presents a revised cognitive behavioral model of SAD and the research supporting these modifications. The chapter's primary focus are five areas: the important role of imagery (and imagery perspective), PEP, the combined cognitive biases hypothesis, fear of positive evaluation (FPE), and the potential role of difficulties in the regulation of emotional responses, including but not limited to anxiety.

Selective Suppression of Interleukin-12 Induction after Macrophage Receptor Ligation

Abstract: Interleukin (IL)-12 is a monocyte- and macrophage-derived cytokine that plays a crucial role in both the innate and the acquired immune response. In this study, we examined the effects that ligating specific macrophage receptors had on the induction of IL-12 by lipopolysaccharide (LPS). We report that ligation of the macrophage Fcγ, complement, or scavenger receptors inhibited the induction of IL-12 by LPS. Both mRNA synthesis and protein secretion were diminished to near-undetectable levels following receptor ligation. Suppression was specific to IL-12 since IL-10 and tumor necrosis factor-α (TNF-α) production were not inhibited by ligating macrophage receptors. The results of several different experimental approaches suggest that IL-12 downregulation was due to extracellular calcium influxes that resulted from receptor ligation. First, preventing extracellular calcium influxes, by performing the assays in EGTA, abrogated FcγR-mediated IL-12(p40) mRNA suppression. Second, exposure of macrophages to the calcium ionophores, ionomycin or A23187, mimicked receptor ligation and inhibited IL-12(p40) mRNA induction by LPS. Finally, bone marrow–derived macrophages from FcR γ chain–deficient mice, which fail to flux calcium after receptor ligation, failed to inhibit IL-12(p40) mRNA induction. These results indicate that the calcium influxes that occur as a result of receptor ligation are responsible for inhibiting the induction of IL-12 by LPS. Hence, the ligation of phagocytic receptors on macrophages can lead to a dramatic decrease in IL-12 induction. This downregulation may be a way of limiting proinflammatory responses of macrophages to extracellular pathogens, or suppressing the development of cell-mediated immunity to intracellular pathogens.

Complications related to percutaneous endoscopic gastrostomy (PEG) tubes. A comprehensive clinical review.

Abstract: Percutaneous endoscopic gastrostomy (PEG) has become the modality of choice for providing enteral access to patients who require long-term enteral nutrition. Although generally considered safe, PEG tube placement can be associated with many potential complications. This review describes a variety of PEG tube related complications as well as strategies for complication avoidance. In addition, the reader is presented with a brief discussion of procedures, techniques, alternatives to PEG tubes, and related issues. Special topics covered in this review include PEG tube placement following previous surgery and PEG tube use in pregnancy.