Citations

Background— The Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) demonstrated that implantable cardioverter-defibrillator (ICD) therapy reduces all-cause mortality in patients with New York Heart Association class II/III heart failure and a left ventricular ejection fraction ≤35% on optimal medical therapy. Whether ICD therapy reduced sudden death caused by ventricular tachyarrhythmias without affecting heart failure deaths in this population is unknown. Methods and Results— SCD-HeFT randomized 2521 subjects to placebo, amiodarone, or shock-only, single-lead ICD therapy. Over a median follow-up of 45.5 months, a total of 666 deaths occurred, which were reviewed by an Events Committee and initially categorized as cardiac or noncardiac. Cardiac deaths were further adjudicated as resulting from sudden death presumed to be ventricular tachyarrhythmic, bradyarrhythmia, heart failure, or other cardiac causes. ICD therapy significantly reduced cardiac mortality compared with placebo (adjusted hazard ratio, 0.76; 95% confidence interval, 0.60 to 0.95) and tachyarrhythmia mortality (adjusted hazard ratio, 0.40; 95% confidence interval, 0.27 to 0.59) and had no impact on mortality resulting from heart failure or noncardiac causes. The cardiac and tachyarrhythmia mortality reductions were evident in subjects with New York Heart Association class II but not in subjects with class III heart failure. The reduction in tachyarrhythmia mortality with ICD therapy was similar in subjects with ischemic and nonischemic disease. Compared with placebo, amiodarone had no significant effect on any mode of death. Conclusions— ICD therapy reduced cardiac mortality and sudden death presumed to be ventricular tachyarrhythmic in SCD-HeFT and had no effect on heart failure mortality. Amiodarone had no effect on all-cause mortality or its cause-specific components, except an increase in non-cardiac mortality in class III patients. Clinical Trial Registration Information— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000609.

Abstract Productive T cell activation requires efficient reorganization of the actin cytoskeleton. We showed previously that the actin-regulatory protein, hematopoietic lineage cell-specific protein 1 (HS1), is required for the stabilization of F-actin and Vav1 at the immunological synapse and for efficient calcium responses. The Tec family kinase IL-2-inducible T cell kinase (Itk) regulates similar aspects of T cell activation, suggesting that these proteins act in the same pathway. Using video microscopy, we show that T cells lacking Itk or HS1 exhibited similar defects in actin responses, extending unstable lamellipodial protrusions upon TCR stimulation. HS1 and Itk could be coimmunoprecipitated from T cell lysates, and GST-pulldown studies showed that Itk’s Src homology 2 domain binds directly to two phosphotyrosines in HS1. In the absence of Itk, or in T cells overexpressing an Itk Src homology 2 domain mutant, HS1 failed to localize to the immunological synapse, indicating that Itk serves to recruit HS1 to sites of TCR engagement. Because Itk is required for phospholipase C (PLC)γ1 phosphorylation and calcium store release, we examined the calcium signaling pathway in HS1−/− T cells in greater detail. In response to TCR engagement, T cells lacking HS1 exhibited diminished calcium store release, but TCR-dependent PLCγ1 phosphorylation was intact, indicating that HS1’s role in calcium signaling is distinct from that of Itk. HS1-deficient T cells exhibited defective cytoskeletal association of PLCγ1 and altered formation of PLCγ1 microclusters. We conclude that HS1 functions as an effector of Itk in the T cell actin-regulatory pathway, and directs the spatial organization of PLCγ1 signaling complexes.

AbstractMultiprotein complexes and other protein‐protein interactions play important roles in virtually all cellular processes. Analysis of coimmunoprecipitation of protein complexes by flow cytometry (IP‐FCM, or “the fly‐p” method) provides a sensitive means to measure these interactions in the native/nondenatured state. First, immunoprecipitating antibodies are covalently coupled to polystyrene latex beads whose low autofluorescence is compatible with flow cytometry. These antibody‐coupled beads are used to immunoprecipitate a specific protein (primary analyte) present in cell lysates. Finally, the protein complexes associated with the beads are probed with fluorochrome‐conjugated antibodies specific for interaction partners, or secondary analytes, that may be associated with the primary analyte. The use of quantitative flow cytometric methodology can allow the semiquantitative fluorescence data generated to be converted into estimated numbers of coassociated molecules on the beads. The method represents a robust technique to assess native protein‐protein interactions without requiring genetic engineering or large sample sizes. Curr. Protoc. Immunol. 87:5.9.1‐5.9.14. © 2009 by John Wiley & Sons, Inc.

Pneumocystis carinii (Pc) causes severe pneumonia in immunocompromised hosts. The binding of Pc trophic forms to alveolar epithelial cells is a central feature of infection, inducing the expression and activation of PcSte20, a gene participating in mating, proliferation, and pseudohyphal growth. In related fungi, Ste20 proteins are generally activated by immediate upstream small G proteins of the Cdc42-like family. PcCdc42 has not been previously described in Pneumocystis . To address the potential role of such a G protein in Pneumocystis , PcCdc42 was cloned from a Pc cDNA library. Using the full-length 576-bp PcCdc42 cDNA sequence, a CHEF blot of genomic DNA yielded a single band, providing evidence that this gene is present as a single copy within the genome. The total length of PcCdc42 cDNA was 576 bp with an estimated molecular mass of ∼38 kDa. BLASTP analysis demonstrated greater than 80% homology with other fungal Cdc42p proteins. Northern analysis indicated equal mRNA expression in both cystic and trophic life forms. Heterologous expression of PcCdc42 in Saccharomyces cerevisiae (Sc) demonstrated that PcCdc42p was able to restore growth in an ScCdc42Δ yeast strain. Additional assays with purified PcCdc42 protein demonstrated GTP binding and intrinsic GTPase activity, which was partially but significantly suppressed by Clostridium difficile toxin B, characteristic of Cdc42 GTPases. Furthermore, PcCdc42 protein was also shown to bind to the downstream PCSte20 kinase partner in the presence (but not the absence) of GTP. These data indicate that Pc possesses a Cdc42 gene expressing an active G protein, which binds the downstream regulatory kinase PcSte20, important in Pc life cycle regulation.

Purpose. Oral mucositis is a serious problem that affects a significant number of hematopoietic cell transplant (HCT) patients. There are many gaps in management, and evidence-based guidelines do not provide consistent recommendations. The purpose of this pilot study was to develop a mucositis oral care protocol for the prevention and management of mucositis in the HCT patient and to evaluate the clinical impact of its implementation. Methods. After receipt of Institutional Review Board approval, all patients admitted to the Hematology—Oncology service for high-dose chemotherapy followed by an autologous or allogeneic HCT were eligible for the study. As part of a change in practice, a new mucositis protocol consisting of a specific oral care regimen was instituted for prevention and treatment of mucositis. Assessment of mucositis began upon admission to the hospital and the patient was evaluated using a mucositis grading scale on a daily basis by the physician and nursing staff. The new mucositis protocol was a part of the HCT service admission orders for each patient. The group of patients treated according to the new mucositis protocol were compared with a retrospective control group consisting of patients who had undergone management of oral mucositis under the previous standard of care. The primary endpoints were to evaluate incidence, severity, and duration of oral mucositis. Secondary endpoints included days requiring narcotics; days of parenteral nutrition, febrile neutropenia, antimicrobial therapy, and length of hospital stay. Results. There were 13 patients enrolled in the control group and 12 patients in the new protocol group. The new protocol resulted in a decreased incidence (100% vs. 75%) and duration (19.2 vs. 8.3 days) of mucositis. Days of maximum grade one and three mucositis were decreased by 56%, and 70%, respectively. Days of maximum grade two mucositis, however increased by 22%. The days of narcotic use were reduced by 19% in the new protocol group (15.8 vs. 12.8 days). All patients in the new protocol group required parenteral nutrition, but days of use were reduced by 41% (17 vs. 10.2 days). The incidence of infection measured by days of febrile neutropenia and antimicrobial therapy were reduced by 35% (10.2 vs. 6.5 days) and 33% (17 vs. 11.4 days). Finally, the overall length of hospital stay was reduced by 7 days (30 vs. 23 days). Conclusion. Implementation of a standardized oral care protocol for mucositis management resulted in a decreased incidence, duration and severity of mucositis, and also reduced the global negative impact of mucositis. Future studies may further evaluate the global impact by adjusting for confounding factors. J Oncol Pharm Practice (2010) 16: 195—204.