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Search Results: 1 - 10 of 313708 matches for " James J Goedert "
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Association of Fecal Microbial Diversity and Taxonomy with Selected Enzymatic Functions
Roberto Flores, Jianxin Shi, Mitchell H. Gail, Pawel Gajer, Jacques Ravel, James J. Goedert
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039745
Abstract: Few microbial functions have been compared to a comprehensive survey of the human fecal microbiome. We evaluated determinants of fecal microbial β-glucuronidase and β-glucosidase activities, focusing especially on associations with microbial alpha and beta diversity and taxonomy. We enrolled 51 healthy volunteers (26 female, mean age 39) who provided questionnaire data and multiple aliquots of a stool, from which proteins were extracted to quantify β-glucuronidase and β-glucosidase activities, and DNA was extracted to amplify and pyrosequence 16S rRNA gene sequences to classify and quantify microbiome diversity and taxonomy. Fecal β-glucuronidase was elevated with weight loss of at least 5 lb. (P = 0.03), whereas β-glucosidase was marginally reduced in the four vegetarians (P = 0.06). Both enzymes were correlated directly with microbiome richness and alpha diversity measures, directly with the abundance of four Firmicutes Clostridia genera, and inversely with the abundance of two other genera (Firmicutes Lactobacillales Streptococcus and Bacteroidetes Rikenellaceae Alistipes) (all P = 0.05–0.0001). Beta diversity reflected the taxonomic associations. These observations suggest that these enzymatic functions are performed by particular taxa and that diversity indices may serve as surrogates of bacterial functions. Independent validation and deeper understanding of these associations are needed, particularly to characterize functions and pathways that may be amenable to manipulation.
Lymphocyte subsets in hemophilic patients with hepatitis C virus infection with or without human immunodeficiency virus co-infection: a nested cross-sectional study
Mingdong Zhang, Thomas R O'Brien, William C Kopp, James J Goedert, for the Multicenter Hemophilia Cohort Study
BMC Blood Disorders , 2005, DOI: 10.1186/1471-2326-5-2
Abstract: The relationship between HCV infection and lymphocyte subpopulations was evaluated rigorously in 120 asymptomatic hemophilic patients, randomly selected from a prospective cohort study. CD4+ T cells, CD8+ T cells, CD19+ B cells, and CD56+ NK cells were quantified by flow cytometry using cryopreserved peripheral blood mononuclear cells of 24 hemophilic patients in each of five age-matched groups [uninfected; chronic HCV with or without human immunodeficiency virus (HIV); and cleared HCV with or without HIV].As expected, patients with HIV had significantly reduced CD4+ and increased CD8+ T cells. Irrespective of HIV, patients with chronic HCV infection had approximately 25% fewer CD19+ B cells than those without chronic HCV infection.These data support the hypothesis that asymptomatic patients with chronic HCV infection have an altered B-lymphocyte population.The natural history of hepatic C virus (HCV) infection may include B-cell diseases. HCV can be detected in peripheral blood mononuclear cells (PBMCs) and may also replicate in these cells [1-3]. Type II cryogloblinemia and some non-Hodgkin lymphomas have been linked to HCV [4], but links between B cells and asymptomatic HCV infection are poorly defined.One study reported that hemophilic patients co-infected with HCV and human immunodeficiency virus (HIV) had reduced B cells and CD4+ T cells [5]. To further characterize PBMC immunophenotypes in patients with chronic or cleared HCV infection, we quantified proportions of CD4+ T cells, CD8+ T cells, B cells, and natural killer (NK) cells in PBMCs of carefully selected, well characterized hemophilic patients.Patients with hemophilia or another congenital coagulation disorder (herein referred to as "hemophilia") enrolled in the Multicenter Hemophilia Cohort Study [6,7] were categorized into five groups: no HIV or HCV infection (HIV-/HCV-); chronic (viremic) HCV infection without HIV (HIV-/HCV RNA+); chronic (viremic) HCV infection with HIV (HIV+/HCV RNA+); cleared (no
Risk of classical Kaposi sarcoma by plasma levels of Epstein-Barr virus antibodies, sCD26, sCD23 and sCD30
Colleen Pelser, Jaap Middeldorp, Sam M Mbulaiteye, Carmela Lauria, Angelo Messina, Enza Viviano, Nino Romano, Francesco Vitale, James J Goedert
Infectious Agents and Cancer , 2010, DOI: 10.1186/1750-9378-5-18
Abstract: In a population-based study of 119 cKS cases, 105 KSHV-seropositive controls, and 155 KSHV-seronegative controls, we quantified plasma soluble cluster of differentiation (sCD) levels and antibodies against Epstein-Barr virus nuclear antigen-1 (anti-EBNA-1) and viral capsid antigen (anti-VCA). Differences between groups in prevalence of low-tertile anti-EBNA-1 and high-tertile anti-VCA were compared by logistic regression. Continuous levels between groups and by presence of cKS co-factors among controls were compared by linear regression and Mann-Whitney-Wilcoxon methods.Comparisons of cKS cases to seropositive controls and of seropositive to seronegative controls revealed no significant differences. However, controls with known cKS cofactors (male sex, nonsmoking, diabetes and cortisone use) had significantly lower levels of anti-EBNA (P = 0.0001 - 0.07) and anti-VCA (P = 0.0001 - 0.03). Levels of sCD26 were significantly lower for male and non-smoking controls (Padj ≤ 0.03), and they were marginally lower with older age and cortisone use (Padj ≤ 0.09).Anti-EBV and sCD26 levels were associated with cofactors for cKS, but they did not differ between cKS cases and matched controls. Novel approaches and broader panels of assays are needed to investigate immunological contributions to cKS.Kaposi sarcoma (KS) develops in develops in a minority of people who have been infected with Kaposi sarcoma-associated herpesvirus (KSHV). KS is the predominant malignancy occurring in people with the acquired immunodeficiency syndrome (AIDS), illustrating that cell-mediated immunity modifies the risk KS. However, the abnormalities with AIDS are so varied in type and severity that dissecting those specifically associated with KS is challenging. Studies of people who do not have overt immunologic abnormalities may be more informative, although consistent, unambiguous perturbations have yet to be reported in non-AIDS KS [1-4].KSHV reactivation with viremia is predictive for KS [5], but s
Dynamical symmetries and the Ermakov invariant
F. Haas,J. Goedert
Physics , 2002, DOI: 10.1016/S0375-9601(00)00835-5
Abstract: Ermakov systems possessing Noether point symmetry are identified among the Ermakov systems that derive from a Lagrangian formalism and, the Ermakov invariant is shown to result from an associated symmetry of dynamical character. The Ermakov invariant and the associated Noether invariant, are sufficient to reduce these systems to quadratures.
Lie symmetries for two-dimensional charged particle motion
F. Haas,J. Goedert
Physics , 2002, DOI: 10.1088/0305-4470/33/25/308
Abstract: We find the Lie point symmetries for non-relativistic two-dimensional charged particle motion. These symmetries comprise a quasi-invariance transformation, a time-dependent rotation, a time-dependent spatial translation and a dilation. The associated electromagnetic fields satisfy a system of first-order linear partial differential equations. This system is solved exactly, yielding four classes of electromagnetic fields compatible with Lie point symmetries.
On the generalized Hamiltonian structure of 3D dynamical systems
F. Haas,J. Goedert
Physics , 2002, DOI: 10.1016/0375-9601(95)00113-H
Abstract: The Poisson structures for 3D systems possessing one constant of motion can always be constructed from the solution of a linear PDE. When two constants of the motion are available the problem reduces to a quadrature and the structure functions include an arbitrary function of them.
On the Hamiltonian structure of Ermakov systems
F. Haas,J. Goedert
Physics , 2002, DOI: 10.1088/0305-4470/29/14/029
Abstract: A canonical Hamiltonian formalism is derived for a class of Ermakov systems specified by several different frequency functions. This class of systems comprises all known cases of Hamiltonian Ermakov systems and can always be reduced to quadratures. The Hamiltonian structure is explored to find exact solutions for the Calogero system and for a noncentral potential with dynamic symmetry. Some generalizations of these systems possessing exact solutions are also identified and solved.
On the Lie symmetries of a class of generalized Ermakov systems
J. Goedert,F. Haas
Physics , 2002, DOI: 10.1016/S0375-9601(98)00020-6
Abstract: The symmetry analysis of Ermakov systems is extended to the generalized case where the frequency depends on the dynamical variables besides time. In this extended framework, a whole class of nonlinearly coupled oscillators are viewed as Hamiltonian Ermakov system and exactly solved in closed form.
On the linearization of the generalized Ermakov systems
F. Haas,J. Goedert
Physics , 2002, DOI: 10.1088/0305-4470/32/15/011
Abstract: A linearization procedure is proposed for Ermakov systems with frequency depending on dynamic variables. The procedure applies to a wide class of generalized Ermakov systems which are linearizable in a manner similar to that applicable to usual Ermakov systems. The Kepler--Ermakov systems belong into this category but others, more generic, systems are also included.
Noether symmetries for two-dimensional charged particle motion
F. Haas,J. Goedert
Physics , 2002, DOI: 10.1088/0305-4470/32/39/309
Abstract: We find the Noether point symmetries for non-relativistic two-dimensional charged particle motion. These symmetries are composed of a quasi-invariance transformation, a time-dependent rotation and a time-dependent spatial translation. The associated electromagnetic field satisfy a system of first-order linear partial differential equations. This system is solved exactly, yielding three classes of electromagnetic fields compatible with Noether point symmetries. The corresponding Noether invariants are derived and interpreted.
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