Publications by authors named "Michelle A Peters"

Background: Rapid-response extracorporeal membrane oxygenation (RR-ECMO) has been implemented at select centers to expedite cannulation for patients placed on ECMO during extracorporeal cardiopulmonary resuscitation (ECPR). In 2008, we established such a program and used it for all pediatric venoarterial ECMO initiations. This study was designed to compare outcomes before and after program implementation.

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Background: Respiratory failure and acute respiratory distress syndrome secondary to H1N1 influenza infection is a source of substantial morbidity and mortality, having caused over 265,000 hospitalizations in the United States in 2009. During the H1N1 pandemic, up to 31% of the H1N1 patients required intensive care unit admission, and many were refractory to maximal conventional therapies. These most critically ill patients may require extracorporeal membrane oxygenation (ECMO) for survival.

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Objective: To report the first successful use of extracorporeal membrane oxygenation for acute respiratory distress syndrome secondary to 2009 pH1N1 influenza A infection in a child status post the Fontan operation for hypoplastic left heart syndrome.

Design: Individual case report.

Setting: Pediatric intensive care unit.

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Objective: We report the process used to rapidly develop a collaborative adult respiratory extracorporeal membrane oxygenation program as a response to caring for young adult patients with refractory hypoxemia in the setting of the pH1N1 pandemic.

Design: Interdisciplinary response of a complex medical system to a public health crisis. PATIENTS, INTERVENTIONS, MEASUREMENTS, AND MAIN RESULTS: After the successful use of extracorporeal membrane oxygenation in young adults with pH1N1-induced acute respiratory distress syndrome refractory to conventional therapies, an adult venovenous extracorporeal membrane oxygenation program was implemented over an 8-wk period.

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Chicken anemia virus (CAV) is a significant immunosuppressive pathogen of chickens, but relatively little is known about the effect of specific mutations on its virulence. In order to study the virulence of CAV, an infection model was developed in embryos. Significant growth depression, measured as a reduction in mean body weight, was found for wild-type CAV infection.

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Chicken anemia virus (CAV) is an immunosuppressive pathogen of chickens. To further examine the role of viral protein 2 (VP2), which possesses dual-specificity protein phosphatase (DSP) activity, in viral cytopathogenicity and its influence on viral growth and virulence, an infectious genomic clone of CAV was subjected to site-directed mutagenesis. Substitution mutations C87R, R101G, K102D and H103Y were introduced into the DSP catalytic motif and R129G, Q131P, R/K/K150/151/152G/A/A, D/E161/162G/G, L163P, D169G and E186G into a region predicted to have a high degree of secondary structure.

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A real-time RT-PCR assay was developed utilizing dual-labeled fluorescent probes binding to VP4 sequence that are specific to the classical (Cl), variant (V) and very virulent (vv) strains of infectious bursal disease virus (IBDV). The assay was highly sensitive and could detect as little as 3 x 10(2) to 3 x 10(3) copies of viral template. Viral genomic copy number could be accurately assayed over a broad range of 7-8 logs of viral genome.

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Novel dual-specificity protein phosphatases (DSPs), which catalyse the removal of phosphate from both phosphotyrosine and phosphoserine/phosphothreonine substrates, have recently been identified in two viruses within the family Circoviridae. Viral protein 2 (VP2) of chicken anemia virus (CAV) and ORF2 of TT virus have been shown to possess DSP activity in vitro. CAV VP2 is unusual in possessing two vicinal cysteines within the protein phosphatase signature motif.

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Thymocyte responses to functional activation are of relevance to the evaluation of the efficacy of in ovo immunotherapies and vaccines in chickens. In this study we have demonstrated differences in chicken thymocyte responses according to developmental age. RNA samples from stimulated and unstimulated chicken thymocytes were assayed for messenger RNA encoding the cytokines interleukin-1beta (IL-1beta), IL-2, interferon-alpha (IFN-alpha), IFN-beta, IFN-gamma and transforming growth factor-beta4 (TGF-beta4), and also components of the major histocompatibility complex (MHC), beta2-microglobulin (beta2M) and the MHC class I alpha-chain (MHC IA).

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The function of viral protein 2 (VP2) of the immunosuppressive circovirus chicken anemia virus (CAV) has not yet been established. We show that the CAV VP2 amino acid sequence has some similarity to a number of eukaryotic, receptor, protein-tyrosine phosphatase (PTPase) alpha proteins as well as to a cluster of human TT viruses within the Sanban group. To investigate if CAV VP2 functions as a PTPase, purified glutathione S-transferase (GST)-VP2 fusion protein was assayed for PTPase activity using the generalized peptide substrates ENDpYINASL and DADEpYLIPQQG (where pY represents phosphotyrosine), with free phosphate detected using the malachite green colorimetric assay.

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