Citations

Abstract Purpose: This phase I, open-label, uncontrolled, ascending-dose study explored the safety, maximum tolerated dose (MTD), pharmacokinetics, and pharmacology of the TLR8 agonist VTX-2337 in subjects with advanced solid tumors or lymphoma. Experimental Design: VTX-2337 doses (0.1–3.9 mg/m2) were administered subcutaneously on days 1, 8, and 15 of each 28-day cycle. Safety/tolerability assessments included adverse events (AE); physical, ophthalmologic, and laboratory evaluations; and electrocardiograms. Dose-limiting toxicities (DLT) were evaluated during the first cycle. Pharmacokinetics were evaluated after the first dose. Plasma samples were quantitatively assessed for chemokines, cytokines, and other inflammatory mediators. Antitumor activity was assessed. Results: Thirty-three subjects were enrolled in 8 cohorts and received an average of 2 treatment cycles (range, 1–8 cycles). Most AEs were grades 1 to 2; the most common drug-related AEs were injection site reactions, chills, pyrexia, and influenza-like illness. One DLT was reported: grade 3 hypotension (3.9 mg/m2). The MTD was considered the highest dose administered. Peak drug plasma levels and total systemic exposure were generally dose proportional. At doses ≥0.4 mg/m2, increases above baseline levels were observed for plasma levels of G-CSF, monocyte chemoattractant protein-1, macrophage inflammatory protein-1β, and TNFα. Eight subjects (24.2%) had a best response of stable disease (median duration, 54.5 days). Conclusions: VTX-2337 is clinically well tolerated and biologically active with a predictable pharmacokinetic profile. Suitable doses for testing in combination studies were identified. Phase II placebo-controlled studies of VTX-2337 in combination with doxorubicin in ovarian cancer, and in combination with platinum chemotherapy, 5 FU, and cetuximab in head and neck cancer have been initiated (NCT #01666444 and NCT#01836029). Clin Cancer Res; 20(14); 3683–91. ©2014 AACR.

BACKGROUNDWith the advent of limits to resident duty hours and the size of teaching services, many academic institutions have introduced nonteaching services, often triaging perceived better teaching cases to the resident services.OBJECTIVETo compare resident versus faculty perceptions of ideal cases for teaching services and compare these perceptions with actual triage decisions made by faculty who assigned patients to either teaching or nonteaching services.DESIGNResidents and hospitalist faculty were surveyed about their perceptions of ideal and actual teaching admissions, first with qualitative, open‐ended questions and then with quantitative, specific questions generated from responses to the first survey. Characteristics of patients admitted to teaching and nonteaching services were analyzed retrospectively and compared with resident and faculty perceptions.RESULTSResidents and faculty agreed that rare cases, patients with unique physical findings, and a variety of pathology were ideal for teaching services and that social admissions, benefactors, and patients with chronic or functional pain were not. Residents believed that traditional (“bread and butter”) medicine cases were under‐represented on the teaching services. Although residents perceived that they received a disproportionate number of older patients, outside transfers, patients with chronic pain, and patients with cancer, the only statistically significant difference was in patient age, with the teaching service actually receiving younger patients (66.7 vs 69.3 years; P = 0.008).CONCLUSIONSResidents and faculty have similar views about ideal teaching cases, but a triage system based on perceived educational merit creates the possibility of resident misperceptions about their case mix, even if patients are distributed relatively equitably. Journal of Hospital Medicine 2014;9:508–514. © 2014 Society of Hospital Medicine

ObjectivesOur objective was to determine if technical changes combined with radiation safety initiatives reduced the radiation dose delivered to patients during congenital catheterization.BackgroundUse of ionizing radiation is necessary during cardiac catheterization. Minimizing radiation dose, while maintaining clinically useful image quality, is an important safety issue. In our congenital heart center intentional practice changes, including technical changes and provider awareness initiatives, were implemented to decrease radiation dose.MethodsData were retrospectively collected for all procedures involving children and adults with congenital heart disease (CHD) undergoing catheterization over 45 months. Cases were divided into three categories including: noninterventional (NI), simple intervention (SI), and complex intervention (CI). The change in dose was modeled as log of cumulative air kerma (Ka,r). The change in Ka,r was evaluated for each procedural category as well as changes occurring as a function of age and weight.ResultsConsidering all procedures (n = 1,082), Ka,r decreased by 61%. In the NI group (n = 481), Ka,r decreased by 71%. In the SI group (n = 424), Ka,r decreased by 74%. The Ka,r for the 10–17 year old group (n = 125) and those ≥18 years (n = 709) decreased 74 and 67%, respectively. The Ka,r decreased 72 and 66% for those 20–60 kg and ≥60 kg, respectively. Groups not showing significant change in Ka,r included CI, age ≤9 years, and weight ≤20 kg.ConclusionsThrough technical changes and provider awareness initiatives, our institution dramatically reduced the radiation dose in the majority of pediatric and adult CHD patients undergoing cardiac catheterization. © 2014 Wiley Periodicals, Inc.

Background and Purpose— The chronological development and natural history of cerebral aneurysms (CAs) remain incompletely understood. We used 14 C birth dating of a main constituent of CAs, that is, collagen type I, as an indicator for biosynthesis and turnover of collagen in CAs in relation to human cerebral arteries to investigate this further. Methods— Forty-six ruptured and unruptured CA samples from 43 patients and 10 cadaveric human cerebral arteries were obtained. The age of collagen, extracted and purified from excised CAs, was estimated using 14 C birth dating and correlated with CA and patient characteristics, including the history of risk factors associated with atherosclerosis and potentially aneurysm growth and rupture. Results— Nearly all CA samples contained collagen type I, which was <5 years old, irrespective of patient age, aneurysm size, morphology, or rupture status. However, CAs from patients with a history of risk factors (smoking or hypertension) contained significantly younger collagen than CAs from patients with no risk factors (mean, 1.6±1.2 versus 3.9±3.3 years, respectively; P =0.012). CAs and cerebral arteries did not share a dominant structural protein, such as collagen type I, which would allow comparison of their collagen turnover. Conclusions— The abundant amount of relatively young collagen type I in CAs suggests that there is an ongoing collagen remodeling in aneurysms, which is significantly more rapid in patients with risk factors. These findings challenge the concept that CAs are present for decades and that they undergo only sporadic episodes of structural change.

Abstract Signaling lymphocyte activation molecule (SLAM) family receptors are critically involved in modulating innate and adaptive immune responses. Several SLAM family receptors have been shown to interact with the adaptor molecule SAP; however, subsequent intracellular signaling is poorly defined. Notably, mutations in SLAM-associated protein (SAP) lead to X-linked lymphoproliferative disease, a rare but fatal immunodeficiency. Although the SLAM family member Ly9 (CD229) is known to interact with SAP, the functions of this receptor have remained elusive. Therefore, we have generated Ly9−/− mice and compared their phenotype with that of SLAM−/− and SAP−/− mice. We report that Ly9−/− T cells exhibit a mild Th2 defect associated with reduced IL-4 production after stimulation with anti-TCR and anti-CD28 in vitro. This defect is similar in magnitude to the previously reported Th2 defect in SLAM−/− mice but is more subtle than that observed in SAP−/− mice. In contrast to SLAM−/− and SAP−/− mice, T cells from Ly9−/− mice proliferate poorly and produce little IL-2 after suboptimal stimulation with anti-CD3 in vitro. We have also found that Ly9−/− macrophages exhibit no defects in cytokine production or bacterial killing as was observed in SLAM−/− macrophages. Additionally, Ly9−/− mice differ from SAP−/− mice in that they foster normal development of NKT cells and mount appropriate T and B cell responses to lymphocytic choriomeningitis virus. We have identified significant phenotypic differences between Ly-9−/− mice as compared with both SLAM−/− and SAP−/− mice. Although Ly9, SLAM, and SAP play a common role in promoting Th2 polarization, Ly-9 is uniquely involved in enhancing T cell activation.

Abstract Wiskott-Aldrich syndrome protein (WASP)-interacting protein (WIP), specifically binds to a region of WASp that is frequently mutated in Wiskott-Aldrich syndrome. Due to the similar phenotypes of WASp- and Vav-deficient T cells, and the putative importance of the WIP/WASp complex in mediating normal signals from the TCR, we investigated the role of WIP in regulating NF-AT/AP-1-mediated gene transcription. We show that WIP has the ability to enhance Vav-mediated activation of NF-AT/AP-1 gene transcription. In addition, we provide evidence that the interaction of WIP with WASp is necessary, but not sufficient for the ability of WIP to regulate NF-AT/AP-1 activity. Finally, we have identified a region in WIP required for its regulation of NF-AT/AP-1 activity. Our data suggests that the WIP-WASp interaction is important for NF-AT/AP-1-mediated gene transcription, and that defects seen in the activation of T cells from WAS patients may be due to the inability of these cells to form a functional WIP/WASp-signaling complex.

Abstract The Vav protooncogene is a multidomain protein involved in the regulation of IL-2 gene transcription in T cells and the development of cell-mediated killing by cytotoxic lymphocytes. We have investigated the differential roles that specific protein subdomains within the Vav protooncogene have in the development of these two distinct cellular processes. Interestingly, a calponin homology (CH) domain mutant of Vav (CH−) fails to enhance NF-AT/AP-1-mediated gene transcription but is still able to regulate the development of cell-mediated killing. The inability of the CH− mutant to enhance NF-AT/AP-1-mediated transcription appears to be secondary to defective intracellular calcium, because 1) the CH− mutant has significantly reduced TCR-initiated calcium signaling, and 2) treatment with the calcium ionophore ionomycin or cotransfection with activated calcineurin restores NF-AT/AP-1-mediated gene transcription. The pleckstrin homology (PH) domain of Vav has also been implicated in regulating Vav activation. We found that deletion of the PH domain of Vav yields a protein that can neither enhance gene transcription from the NF-AT/AP-1 reporter nor enhance TCR- or FcR-mediated killing. In contrast, the PH deletion mutant of Vav is able to regulate the development of natural cytotoxicity, indicating a functional dichotomy for the PH domain in the regulation of these two distinct forms of killing. Lastly, mutation of three tyrosines (Y142, Y160, and Y174) within the acidic domain of Vav has revealed a potential negative regulatory site. Replacement of all three tyrosines with phenylalanine results in a hyperactive protein that increases NF-AT/AP-1-mediated gene transcription and enhances cell-mediated cytotoxicity. Taken together, these data highlight the differential roles that specific subdomains of Vav have in controlling distinct cellular functions. More broadly, the data suggest that separate lymphocyte functions can potentially be modulated by domain-specific targeting of Vav and other critical intracellular signaling molecules.

Abstract The two isoforms of phospholipase C (PLC)-γ couple immune recognition receptors to important calcium- and protein kinase C-dependent cellular functions. It has been assumed that PLC-γ1 and PLC-γ2 have redundant functions and that the receptors can use whichever PLC-γ isoform is preferentially expressed in a cell of a given hemopoietic lineage. In this study, we demonstrate that ITAM-containing immune recognition receptors can use either PLC-γ1 or PLC-γ2, whereas the novel NK cell-activating receptor NKG2D preferentially couples to PLC-γ2. Experimental models evaluating signals from either endogenous receptors (FcR vs NKG2D-DAP10) or ectopically expressed chimeric receptors (with ITAM-containing cytoplasmic tails vs DAP10-containing cytoplasmic tails) demonstrate that PLC-γ1 and PLC-γ2 both regulate the functions of ITAM-containing receptors, whereas only PLC-γ2 regulates the function of DAP10-coupled receptors. These data suggest that specific immune recognition receptors can differentially couple to the two isoforms of PLC-γ. More broadly, these observations reveal a basis for selectively targeting the functions initiated by distinct immune recognition receptors.

Abstract Stimulation of lymphocytes through multichain immune recognition receptors activates multiple signaling pathways. Adaptor proteins play an important role in integrating these pathways by their ability to simultaneously bind multiple signaling components. Recently, the 3BP2 adaptor protein has been shown to positively regulate the transcriptional activity of T cells. However, the mechanisms by which signaling components are involved in this regulation remain unclear, as does a potential role for 3BP2 in the regulation of other cellular functions. Here we describe a positive regulatory role for 3BP2 in NK cell-mediated cytotoxicity. We also identify p95vav and phospholipase C-γ isoforms as binding partners of 3BP2. Our results show that tyrosine-183 of 3BP2 is specifically involved in this interaction and that this residue critically influences 3BP2-dependent function. Therefore, 3BP2 regulates NK cell-mediated cytotoxicity by mobilizing key downstream signaling effectors.