The postcardiac injury syndrome: case report and review of the literature

The postcardiac injury syndrome (PCIS) includes the postmyocardial infarction syndrome, the postcommissurotomy syndrome, and the postpericardiotomy syndrome. Dressler reported a series of patients who developed a pericarditis-like illness days to weeks after a myocardial infarction. Postcardiac injury syndrome also has been observed after cardiac surgery, percutaneous intervention, pacemaker implantation, and radiofrequency ablation. Postcardiac injury syndrome is characterized by pleuritic chest pain, low-grade fever, an abnormal chest x-ray, and the presence of exudative pericardial and/or pleural effusions. The pathophysiology of PCIS involves auto-antibodies that target antigens exposed after damage to cardiac tissue. The treatment of PCIS includes the use of nonsteroidal anti-inflammatory drugs and corticosteroids. Prophylactic use of corticosteroids before cardiac surgery has not been effective in preventing PCIS. The widespread use of reperfusion therapy and cardiac medications with anti-inflammatory properties may have reduced the incidence of PCIS. Although PCIS can follow a relapsing course, it does carry a favorable prognosis.     

The development of a fluorescence in situ hybridization assay for the detection of dysplasia and adenocarcinoma in Barrett's esophagus

The goal of this study was to identify a set of fluorescence in situ hybridization probes for the detection of dysplasia and adenocarcinoma in patients with Barrett's esophagus. We examined 170 brushing specimens from 138 patients with Barrett's esophagus or a history of Barrett's esophagus using fluorescence in situ hybridization with probes to 5p15, 5q21-22, centromere 7, 7p12, 8q24.12-13, centromere 9, 9p21, centromere 17, 17p13.1, 17q11.2-12, 20q13.2, and centromere Y. Receiver-operator curves were used to determine the sensitivity and specificity of various four-probe combinations for detecting low-grade dysplasia, high-grade dysplasia, and esophageal adenocarcinoma. Endoscopic biopsy results were used as the gold standard. Numerous four-probe combinations provided a similarly high sensitivity and specificity. Of these, a set consisting of probes to 8q24, 9p21, 17q11.2, and 20q13.2 was found to have a sensitivity and specificity, respectively, of 70% and 89% for low-grade dysplasia, 84% and 93% for high-grade dysplasia, and 94% and 93% for esophageal adenocarcinoma. This probe set was chosen for future prospective clinical evaluations based on its high sensitivity and specificity, its ability to distinguish adenocarcinoma and high-grade or low-grade dysplasia from lesser diagnostic categories, and the favorable signal quality for each of the probes.     

Combinatorial biosynthesis of novel antibiotics related to daptomycin

Daptomycin, a cyclic lipopeptide produced by Streptomyces roseosporus, is the active ingredient of Cubicin (daptomycin-for-injection), a first-in-class antibiotic approved for treatment of skin and skin-structure infections caused by Gram-positive pathogens and bacteremia and endocarditis caused by Staphylococcus aureus, including methicillin-resistant strains. Genetic engineering of the nonribosomal peptide synthetase (NRPS) in the daptomycin biosynthetic pathway was exploited for the biosynthesis of novel active antibiotics. lambda-Red-mediated recombination was used to exchange single or multiple modules in the DptBC subunit of the NRPS to modify the daptomycin cyclic peptide core. We combined module exchanges, NRPS subunit exchanges, inactivation of the tailoring enzyme glutamic acid 3-methyltransferase, and natural variations of the lipid tail to generate a library of novel lipopeptides, some of which were as active as daptomycin against Gram-positive bacteria. One compound was more potent against an Escherichia coli imp mutant that has increased outer membrane permeability. This study established a robust combinatorial biosynthesis platform to produce novel peptide antibiotics in sufficient quantities for antimicrobial screening and drug development.     

Shp1 regulates T cell homeostasis by limiting IL-4 signals

The protein-tyrosine phosphatase Shp1 is expressed ubiquitously in hematopoietic cells and is generally viewed as a negative regulatory molecule. Mutations in Ptpn6, which encodes Shp1, result in widespread inflammation and premature death, known as the motheaten (me) phenotype. Previous studies identified Shp1 as a negative regulator of TCR signaling, but the severe systemic inflammation in me mice may have confounded our understanding of Shp1 function in T cell biology. To define the T cell–intrinsic role of Shp1, we characterized mice with a T cell–specific Shp1 deletion (Shp1^fl/fl CD4-cre). Surprisingly, thymocyte selection and peripheral TCR sensitivity were unaltered in the absence of Shp1. Instead, Shp1^fl/fl CD4-cre mice had increased frequencies of memory phenotype T cells that expressed elevated levels of CD44. Activation of Shp1-deficient CD4⁺ T cells also resulted in skewing to the Th2 lineage and increased IL-4 production. After IL-4 stimulation of Shp1-deficient T cells, Stat 6 activation was sustained, leading to enhanced Th2 skewing. Accordingly, we observed elevated serum IgE in the steady state. Blocking or genetic deletion of IL-4 in the absence of Shp1 resulted in a marked reduction of the CD44^hi population. Therefore, Shp1 is an essential negative regulator of IL-4 signaling in T lymphocytes.T cells are characterized by their ability to expand dramatically in an antigen-specific manner during an immune challenge. After an initial immune response, a small proportion of responding T cells survive and give rise to memory cells (Bruno et al., 1996). Memory T cells express elevated levels of CD44 and can be divided further into central-memory (CD62L^hi CCR7^hi) and effector-memory (CD62L^lo CCR7^lo) compartments. However, not all T cells that display the phenotype of memory cells are the product of a classical antigen-specific immune response (Sprent and Surh, 2011). For example, such cells are found in unimmunized mice, including those raised in germ-free and antigen-free conditions (Dobber et al., 1992; Vos et al., 1992). The precise ontogeny of such cells remains elusive, although several mechanisms by which naive cells can adopt a memory phenotype have been characterized. Naive T cells introduced into lymphopenic environments adopt a memory phenotype through a process of homeostatic proliferation in response to IL-7 and MHC (Goldrath et al., 2000; Murali-Krishna and Ahmed, 2000). Additionally, increased production of IL-4 has been linked to the development of memory phenotype–innate T cell populations in studies of several knockout mouse models (Lee et al., 2011).The T cell response is tightly regulated by the balance of phosphorylation and dephosphorylation of intracellular signaling molecules. Shp1 (encoded by Ptpn6) is a protein tyrosine phosphatase expressed ubiquitously in hematopoietic cells and has been broadly characterized as a negative regulator of immune cell activation (Pao et al., 2007a; Lorenz, 2009). The physiological relevance of Shp1 as a key negative regulator of the immune response is illustrated by the motheaten (me) and motheaten viable (me^v) mutations, which ablate Shp1 expression or greatly reduce Shp1 activity, respectively (Shultz et al., 1993; Tsui et al., 1993). Homozygous me/me or me^v/me^v mice (hereafter, referred to collectively as me mice) suffer from severe systemic inflammation and autoimmunity, which result in retarded growth, myeloid hyperplasia, hypergammaglobulinemia, skin lesions, interstitial pneumonia, and premature death. More recently, a study has identified a third allele of Ptpn6, named spin, which encodes a hypomorphic form of Shp1 (Croker et al., 2008). Mice homozygous for spin develop a milder autoimmune/inflammatory disease that is ablated in germ-free conditions.Shp1 has been implicated in signaling from many immune cell surface receptors (Zhang et al., 2000; Neel et al., 2003), including the TCR (Plas et al., 1996; Lorenz, 2009), BCR (Cyster and Goodnow, 1995; Pani et al., 1995), NK cell receptors (Burshtyn et al., 1996; Nakamura et al., 1997), chemokine receptors (Kim et al., 1999), FAS (Su et al., 1995; Takayama et al., 1996; Koncz et al., 2008), and integrins (Roach et al., 1998; Burshtyn et al., 2000). Shp1 also has been demonstrated to regulate signaling from multiple cytokine receptors by dephosphorylating various Jak (Klingmüller et al., 1995; Jiao et al., 1996; Minoo et al., 2004) and/or Stat (Kashiwada et al., 2001; Xiao et al., 2009) molecules. Several of these cytokines are pertinent to T cell biology. For example, Stat 5 is an essential mediator of signals from IL-2 and IL-7 (Rochman et al., 2009). IL-4 signaling results in Stat 6 phosphorylation and has potent Th2 skewing effects. Additionally, IL-4 has mitogenic effects on CD8⁺ T cells (Rochman et al., 2009). Notably, mutation of the immunoreceptor tyrosine-based inhibitory motif (ITIM) in IL-4Rα results in ablation of Shp1 binding and hypersensitivity to IL-4 stimulation (Kashiwada et al., 2001), implicating Shp1 as a regulator of this cytokine receptor.Although development of the me phenotype does not require T cells (Shultz, 1988; Yu et al., 1996), several aspects of T cell biology reportedly are controlled by Shp1 (Lorenz, 2009). Most previous studies that examined the role of Shp1 in T cells used cells derived from me/me or me^v/me^v mice (Carter et al., 1999; Johnson et al., 1999; Zhang et al., 1999; Su et al., 2001) or cells expressing a dominant-negative allele of Shp1 (Plas et al., 1996, 1999; Zhang et al., 1999). Several such reports have concluded that Shp1 negatively regulates the strength of TCR signaling during thymocyte development and/or peripheral activation (Carter et al., 1999; Johnson et al., 1999; Plas et al., 1999; Zhang et al., 1999; Su et al., 2001). Despite the large number of studies that implicate Shp1 in control of TCR signaling, there is no consensus on which component of the TCR signaling cascade is targeted by the catalytic activity of Shp1. Suggested Shp1 targets downstream of T cell activation include TCR-ζ (Chen et al., 2008), Lck (Lorenz et al., 1996; Stefanová et al., 2003), Fyn (Lorenz et al., 1996), ZAP-70 (Plas et al., 1996; Chen et al., 2008), and SLP-76 (Mizuno et al., 2005). Shp1 also is implicated in signal transduction downstream of several immune inhibitory receptors that negatively regulate T cell activity, such as PD-1 (Chemnitz et al., 2004), IL-10R (Taylor et al., 2007), CEACAM1 (Lee et al., 2008), and CD5 (Perez-Villar et al., 1999).The severe inflammation characteristic of the me phenotype might have confounded studies examining the cell-intrinsic role of Shp1 in various hematopoietic cell types. We previously generated a floxed Shp1 allele that facilitates analysis of the role of Shp1 in various lineages (Pao et al., 2007b). Previous studies have used this approach to study the role of Shp1 in T cells during antiviral and antitumor immune responses, respectively (Fowler et al., 2010; Stromnes et al., 2012). However, a more fundamental analysis of the cell-intrinsic role of Shp1 during T cell development, homeostasis, and activation has not been reported. Here, we provide evidence that a major role for Shp1 in T cells is to maintain normal T cell homeostasis through negative regulation of IL-4 signaling.     

Cytoskeletal-mediated tension modulates the directed self-assembly of microtissues

The ability of cells to self-assemble into a microtissue such as a spheroid has been attributed mainly to intercellular cohesiveness achieved by the binding of surface membrane proteins such as cadherins. However, highly dynamic and complex cytoskeletal rearrangements are coordinated with these binding events and therefore are likely to participate in self-assembly. By inhibiting such cytoskeletal activity, Y-27632 has been used to prevent and treat fibrotic disease. Here, we used the Rho kinase inhibitor to investigate the role that cellular contraction plays in self-assembly. Normal human fibroblasts (NHFs), Reuber-H35 hepatoma cells (H35s), and mixes of the two (hybrid) were treated with drug during directed self-assembly of microtissues in nonadhesive, micromolded hydrogels. The kinetics of self-assembly of both constrained and unconstrained NHF microtissues were dramatically slowed by the drug, and inhibition was dose responsive and reversible. Although sorting of NHFs and H35s occurred normally in the presence of drug, Y-27632-treated NHFs sorted to the outside of a spheroid when mixed with untreated NHFs. When mixed with H35s in trough micromolds, NHFs could drive spheroid formation from the core of the hybrid microtissues even in small numbers relative to H35s (1:19). These findings demonstrate that cellular contraction controls the kinetics of self-assembly and suggests that NHFs within the core of a microtissue can transmit contractile forces through heterotypic bonds with H35s. The control of directed self-assembly using fibroblasts and contraction inhibitors may be useful for in vitro tissue engineering as well as represent an in vitro model for fibrotic disease.     

Communicating side effect risks in a tamoxifen prophylaxis decision aid: The debiasing influence of pictographs

Objective

To experimentally test whether using pictographs (image matrices), incremental risk formats, and varied risk denominators would influence perceptions and comprehension of side effect risks in an online decision aid about prophylactic use of tamoxifen to prevent primary breast cancers.

Methods

We recruited 631 women with elevated breast cancer risk from two healthcare organizations. Participants saw tailored estimates of the risks of 5 side effects: endometrial cancer, blood clotting, cataracts, hormonal symptoms, and sexual problems. Presentation format was randomly varied in a three factor design: (A) risk information was displayed either in pictographs or numeric text; (B) presentations either reported total risks with and without tamoxifen or highlighted the incremental risk most relevant for decision making; and (C) risk estimates used 100 or 1000 person denominators. Primary outcome measures included risk perceptions and gist knowledge.

Results

Incremental risk formats consistently lowered perceived risk of side effects but resulted in low knowledge when displayed by numeric text only. Adding pictographs, however, produced significantly higher comprehension levels.

Conclusions

Pictographs make risk statistics easier to interpret, reducing biases associated with incremental risk presentations.

Practice implications

Including graphs in risk communications is essential to support an informed treatment decision-making process.