Publications by authors named "Valsamakis A"

Article Synopsis
  • - Timothy syndrome, caused by variants in the CACNA1C gene, was originally recognized for its cardiac symptoms (long QT syndrome) and physical abnormalities (syndactyly), but more recent research has unveiled a wider range of symptoms associated with different CACNA1C variants.
  • - A survey was conducted with parents of Timothy syndrome patients to gather information on various symptoms, grouping participants by genetic type and initial diagnosis to compare their conditions.
  • - The study found that patients commonly show both cardiac and extra-cardiac symptoms, such as neurodevelopmental issues and respiratory problems, regardless of their classification, indicating that the current understanding of "non-syndromic" cases may not fully capture the complexity of the disease.
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Timothy syndrome (OMIM #601005) is a rare disease caused by variants in the gene . Timothy syndrome patients were first identified as having a cardiac presentation of Long QT and syndactyly of the fingers and/or toes, and an identical variant in , Gly406Arg. However, since this original identification, more individuals harboring diverse variants in have been identified and have presented with various cardiac and extra-cardiac symptoms.

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Importance: Head and neck squamous cell carcinoma is a highly lethal cancer that is often associated with human papillomavirus (HPV). Recent studies have shown promise in the use of HPV DNA detection in salivary rinses and plasma as a factor associated with a future diagnosis of HPV-positive oropharynx cancer (HPVOPC). However, the use of plasma and salivary HPV DNA detection in defining risk for recurrence in the context of a prospective, phase 3, clinical trial coupled with standardized clinical surveillance has not been reported.

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Human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) diagnostic testing algorithms recommended by the Centers for Disease Control involve up to three tests and rely mostly on detection of viral antigen and host antibody responses. HIV-1 p24 antigen/HIV-1/HIV-2 antibody-reactive specimens are confirmed with an immunochromatographic HIV-1/HIV-2 antibody differentiation assay, and negative or indeterminate results from the differentiation assay are resolved by an HIV-1-specific nucleic acid amplification test (NAT). The performance of a proposed alternative algorithm using the cobas HIV-1/HIV-2 qualitative NAT as the differentiation assay was evaluated in subjects known to be infected with HIV-1 ( = 876) or HIV-2 ( = 139), at low ( = 6,017) or high ( = 1,020) risk of HIV-1 infection, or at high-risk for HIV-2 infection ( = 498) (study A).

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The GenMark Dx ePlex Respiratory Pathogen Panel (RP) is a multiplexed nucleic acid test for the qualitative detection of common viral and a few bacterial causes of respiratory tract infections. The ePlex RP has received FDA clearance for nasopharyngeal swab (NPS) specimens collected in viral transport media. In this study, we evaluated the performance of the ePlex RP panel in comparison to the NxTAG Respiratory Pathogen Panel (NxTAG-RPP) from Luminex in use in our laboratory, not only for NPS but also for bronchoalveolar lavage specimens (BAL).

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Article Synopsis
  • Treatment of ganciclovir-resistant cytomegalovirus (CMV) infections in transplant patients is challenging, with cidofovir (CDV) being one of the few options, despite its harmful side effects.
  • A study reviewed outcomes in 16 transplant patients treated with CDV, revealing a high rate of complications like nephrotoxicity and uveitis, and 50% failure in clearing CMV DNAemia.
  • The findings stress the need for better treatment alternatives due to high mortality rates and significant risks associated with CDV in this patient group.
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Background: Geenius HIV 1/2 Supplemental Assay (Geenius; Bio-Rad Laboratories) is the only Food and Drug Administration-approved HIV-1/HIV-2 antibody differentiation test for the second step in the HIV laboratory testing algorithm. We characterized the occurrence of true HIV-1 and HIV-2 infections as well as false results in 6 US clinical laboratories using Geenius.

Methods: We examined routine HIV testing outcome data from the time the laboratories began using the algorithm with Geenius until September 30, 2017.

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Background: Few reports exist on pre-engraftment cytomegalovirus (CMV) DNAemia in allogeneic blood or marrow transplant (allo BMT) recipients. We describe this clinical entity, its management, and the potential effect of 3 different quantitative CMV deoxyribonucleic acid (DNA) tests used during the 6-year study period.

Methods: We performed a retrospective, single-center study of allo BMT recipients from 2010 to 2015 who developed CMV DNAemia before neutrophil recovery (absolute neutrophil count [ANC] <1000 cells/mm, "pre-engraftment CMV") or who became neutropenic concomitant with detectable CMV DNA ("peri-engraftment CMV").

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Background: We aimed to use genomic data for optimizing polymerase chain reaction (PCR) primer/probe sets for detection of human papillomavirus (HPV)-16 in body fluids of patients with HPV-related head and neck squamous cell carcinoma (HPV-HNSCC).

Methods: We used genomic HPV-HNSCC sequencing data from a single institutional and a TCGA cohort. Optimized primer/probe sets were designed and tested for analytical performance in CaSki HPV-16 genome and confirmed in salivary rinse samples from patients with HPV-HNSCC.

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Human parechovirus (HPeV) infections cause a broad array of clinical manifestations ranging from gastrointestinal or respiratory illness to central nervous system (CNS) diseases. Though nucleic acid amplification tests (NAATs) for detection of HPeVs have been described, a need exists for sensitive and specific NAATs with internal control (IC). This study describes optimization and evaluation of a novel, real-time reverse transcription PCR (RT-PCR) test for detection of HPeV from CSF using EliTech HPeV Research-Use-Only detection reagent, MS2 IC and quantified HPeV control.

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Background And Objectives: Accurate, sensitive, and specific tests for detection and monitoring of hepatitis C virus (HCV) RNA concentrations are essential for diagnosis and management of HCV infections. We evaluated the next-generation reverse-transcription real-time PCR test, cobas HCV test for use with the cobas 6800/8800 systems ("cobas HCV") by determining its analytical performance characteristics and clinical utility for the diagnosis and therapeutic monitoring of chronic HCV infections.

Methods: The limit of detection (LOD), linearity, precision, specificity, matrix equivalence of plasma and serum, and quantitative agreement with the COBAS AmpliPrep/COBAS TaqMan HCV Test version 2.

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Objective: Data comparing hepatitis B virus (HBV) infection in HIV-infected [HIV(+)], and HIV-uninfected [HIV(-)] individuals recruited into the same study are limited. HBV infection status and chronic hepatitis B (cHB) were characterized in a multinational clinical trial: HIV Prevention Trials Network (HPTN 052).

Method: HBV infection status at enrollment was compared between HIV(+) (N = 1241) and HIV(-) (N = 1232) from 7 HBV-endemic countries.

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A patient developed disseminated adenovirus infection following bone marrow transplant. TaqMan real-time PCR showed reduced maximum fluorescence in the amplification curve from all plasma samples. Sequencing revealed three single nucleotide mismatches between the TaqMan probe and probe binding region.

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Chronic hepatitis B, C, and D virus infections contribute significantly to the morbidity and mortality of immunocompromised individuals. To contextualize discussion of these infections in immunocompromised patients, this paper provides an overview of aspects of infection in normal hosts. It then describes differences in disease, diagnostic testing, and therapeutic management observed in immunocompromised patients.

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Background: Antiviral-resistant or refractory cytomegalovirus (CMV) infection is challenging, and salvage therapies, foscarnet, and cidofovir, have significant toxicities. Several investigational anti-CMV agents are under development, but more information is needed on outcomes of current treatments to facilitate clinical trial design for new drugs.

Methods: Records of solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients at a single center over a 10-year period were reviewed retrospectively to characterize those who had received foscarnet treatment for ganciclovir-resistant or refractory CMV infection.

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Background.  Autochthonous hepatitis E virus (HEV) infection has been reported in over 200 solid organ transplant (SOT) recipients since 2006, yet little is known about the burden of HEV among SOT recipients in North America. We performed a retrospective, cross-sectional study to investigate the prevalence and risk factors associated with HEV infection among SOT recipients at our institution.

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Epstein-Barr virus (EBV) is a ubiquitous virus that establishes a latent infection within the host and in some cases can lead to the development of EBV-associated lymphomas, lymphoproliferative disorders, hemophagocytic lymphohistiocytosis, solid tumors, and other diseases. We studied the clinical significance of detecting EBV DNA in the plasma and peripheral blood mononuclear cells (PBMCs) of 2146 patients who had blood specimens sent to the Johns Hopkins Hospital clinical laboratory for viral quantitative real-time polymerase chain reaction assay over a 5-year period. Within this largely immunocompromised and hospitalized cohort, 535 patients (25%) had EBV detected in plasma or PBMCs.

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Purpose: To devise and implement a practice algorithm that would enable rapid detection and appropriate furlough of hospital employees with adenoviral conjunctivitis in order to prevent healthcare-associated epidemic keratoconjunctivitis.

Design: Evaluation of an ongoing quality assurance/improvement initiative.

Methods: Employees of Johns Hopkins Hospital with signs and symptoms of adenoviral conjunctivitis underwent evaluation by nurse practitioners in Occupational Health and rapid diagnostic testing by real-time polymerase chain reaction (PCR).

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Background: Ventricular assist devices (VADs) have been associated with immune activation and sensitization. We observed several cases of false-positive (FP) hepatitis C virus (HCV) antibody (Ab) tests in patients being evaluated for orthotopic heart transplant (OHT), prompting us to investigate this further.

Methods: We reviewed all VAD and OHT cases at Johns Hopkins from 2005 to 2012.

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Monitoring peripheral blood for evidence of BK viremia through quantitative real-time PCR testing is an important management tool that allows for interventions that prevent nephropathy in renal allograft patients. This study compared the performance of 3 different real-time PCR assays for BKV quantification including 2 noncommercial tests (a historical assay "PEP" and 1 with improved genotypic inclusivity "V3T3") and 1 using commercial reagents (Qiagen/artus, "artus") after nucleic acid extraction of plasma with a single automated instrument (QIAsymphony). The measurable ranges (log10 copies/mL) were 2.

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Background: Timely and accurate diagnosis of influenza remains a challenge but is critical for patients who may benefit from antiviral therapy. This study determined the test characteristics of provider diagnosis of influenza, final ED electronic medical record (EMR) diagnosis of influenza, and influenza-like illness (ILI) in patients recommended to receive antiviral treatment according to Centers for Disease Control and Prevention (CDC) guidelines. In addition, we evaluated the compliance with CDC antiviral guidelines.

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Hepatitis E virus (HEV) is an emerging cause of viral hepatitis among immunocompromised individuals in developed countries. Yet the diagnosis of HEV infection in the United States remains challenging, because of the variable sensitivity and specificity of currently available tests, and the lack of a US Food and Drug Administration-approved test. We report a case of multiple discordant HEV serology results in a pediatric liver transplant recipient with idiopathic hepatitis, and review the challenges to diagnosis of HEV infection in the United States.

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We prospectively evaluated the performance of Cepheid's GeneXpert Xpert Flu assay in a target population of 281 adults presenting to the emergency department with an acute respiratory illness who met Centers for Disease Control and Prevention (CDC) criteria for recommended antiviral treatment. Compared with the Prodesse ProFlu+ assay, Xpert Flu had an overall sensitivity of 95.3% and specificity of 99.

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