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Search Results: 1 - 10 of 486597 matches for " John A. Zaia "
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Donor killer immunoglobulin-like receptor genes and reactivation of cytomegalovirus after HLA-matched hematopoietic stem-cell transplantation: HLA-C allotype is an essential cofactor
Carolyn E. Behrendt,John A. Zaia
Frontiers in Immunology , 2013, DOI: 10.3389/fimmu.2013.00036
Abstract: Natural killer (NK) cells whose killer immunoglobulin-like receptors (KIRs) recognize human leukocyte antigen (HLA) ligand are “licensed” for activity. In contrast, non-licensed NK cells display KIRs for which ligand is absent from the self genotype and are usually hyporesponsive. Surprisingly, non-licensed cells are active in tumor control after hematopoietic stem-cell transplantation (HSCT) and dominate NK response to murine cytomegalovirus (CMV) infection. From those reports, we hypothesized that control of human CMV early after HSCT is influenced by donor KIR genes whose HLA ligand is absent-from-genotype of HLA-matched donor and recipient. To investigate, we studied CMV reactivation through Day 100 after grafts involving CMV-seropositive donor and/or recipient. A multivariate proportional rates model controlled for variability in surveillance and established covariates including acute graft-versus-host disease; statistical significance was adjusted for testing of multiple KIRs with identified HLA class I ligand (2DL1, 2DL2/3, 2DS1, 2DS2, full-length 2DS4, 3DL1/3DS1, 3DL2). Among HSCT recipients (n = 286), CMV reactivation-free survival time varied with individual donor KIR genes evolutionarily specific for HLA-C: when ligand was absent from the donor/recipient genotype, inhibitory KIRs 2DL2 (P < 0.0001) and 2DL1 (P = 0.015) each predicted inferior outcome, and activating KIRs 2DS2 (P < 0.0001), 2DS1 (P = 0.016), and 2DS4 (P = 0.016) each predicted superior outcome. Otherwise, with ligand present-in-genotype, donor KIR genes had no effect. In conclusion, early after HLA-matched HSCT, individual inhibitory and activating KIR genes have qualitatively different effects on risk of CMV reactivation; unexpectedly, absence of HLA-C ligand from the donor/recipient genotype constitutes an essential cofactor in these associations. Being KIR- and HLA-C-specific, these findings are independent of licensing via alternate NK cell receptors (NKG2A, NKG2C) that recognize HLA-E.
Development of Hematopoietic Stem Cell Based Gene Therapy for HIV-1 Infection: Considerations for Proof of Concept Studies and Translation to Standard Medical Practice
David L. DiGiusto,Rodica Stan,Amrita Krishnan,Haitang Li,John J. Rossi,John A. Zaia
Viruses , 2013, DOI: 10.3390/v5112898
Abstract: Over the past 15 years we have been investigating an alternative approach to treating HIV-1/AIDS, based on the creation of a disease-resistant immune system through transplantation of autologous, gene-modified (HIV-1-resistant) hematopoietic stem and progenitor cells (GM-HSPC). We propose that the expression of selected RNA-based HIV-1 inhibitors in the CD4+ cells derived from GM-HSPC will protect them from HIV-1 infection and results in a sufficient immune repertoire to control HIV-1 viremia resulting in a functional cure for HIV-1/AIDS. Additionally, it is possible that the subset of protected T cells will also be able to facilitate the immune-based elimination of latently infected cells if they can be activated to express viral antigens. Thus, a single dose of disease resistant GM-HSPC could provide an effective treatment for HIV-1+ patients who require (or desire) an alternative to lifelong antiretroviral chemotherapy. We describe herein the results from several pilot clinical studies in HIV-1 patients and our strategies to develop second generation vectors and clinical strategies for HIV-1+ patients with malignancy who require ablative chemotherapy as part of treatment and others without malignancy. The important issues related to stem cell source, patient selection, conditioning regimen and post-infusion correlative studies become increasingly complex and are discussed herein.
Da gera??o espontanea à química prebiótica
Zaia, Dimas A. M.;
Química Nova , 2003, DOI: 10.1590/S0100-40422003000200020
Abstract: in the present paper, a historical view from spontaneous generation of life to oparin-haldane hypothesis was discussed. it was also showed what is the main concern of the field of prebiotic chemistry. several aspects of prebiotic chemistry such as synthesis of biomolecules and biopolymers, primitive metabolism and genetic code, and the importance of the adsorption for the origin of life were discussed.
Da gera o espontanea à química prebiótica
Zaia Dimas A. M.
Química Nova , 2003,
Abstract: In the present paper, a historical view from spontaneous generation of life to Oparin-Haldane hypothesis was discussed. It was also showed what is the main concern of the field of prebiotic chemistry. Several aspects of prebiotic chemistry such as synthesis of biomolecules and biopolymers, primitive metabolism and genetic code, and the importance of the adsorption for the origin of life were discussed.
Synthesis of guanidine from ammonium thiocyanate in solid state
Zaia, Dimas A. M.;Santana, Henrique de;Toppan, Rodrigo;Zaia, Cássia T. B. V.;
Journal of the Brazilian Chemical Society , 2004, DOI: 10.1590/S0103-50532004000200006
Abstract: guanidine is an important substance for modern living beings as well as for the prebiotic chemistry. we studied the reaction between ammonium and thiocyanate species in solid state with different substances (river sand, kaolin, transition metals, salts of seawater) and temperatures (80, 120 and 150 oc). the recoveries of thiocyanate and ammonium in the samples with river sand or kaolin at 150 oc were statistically different (p<0.05) from the recoveries of thiocyanate and ammonium in the sample without them. the decomposition of ammonium thiocyanate in the samples river sand or kaolin at 150 oc was about 40%. kaolin showed to have more effect on the synthesis guanidine than river sand, because, the concentrations of guanidine in the samples with kaolin were always bigger than in the samples with river sand. the decomposition of ammonium thiocyanate in the samples with transition metals plus river sand at 120 oc was about 30%. the salts of seawater or transition metals plus ammonium thiocyanate plus river sand (120 oc) showed to increase the concentration of thiourea (seawater: 538%; transition metals: 357%) or guanidine (seawater: 393%, transition metals: 806%) when they were compared to the samples without them. when the results obtained with sample of ammonium thiocyanate were compared to the samples of ammonium thiocyanate (at 120 oc) plus salts of seawater or transition metals also an increased on the production of thiourea (168%) and guanidine (268%) was obtained, respectively. the yield for the synthesis of guanidine showed in this paper is better than that obtained by other authors. experiments showed that iron (iii) is involving in the formation of the yellow compound and raman spectra showed this compound could be sulphur.
Adsorption of L-amino Acids on Sea Sand
Zaia, Dimas A. M.;Vieira, Heberth J.;Zaia, Cássia T. B. V.;
Journal of the Brazilian Chemical Society , 2002, DOI: 10.1590/S0103-50532002000500023
Abstract: a study of adsorption of l-alanine, l-tyrosine, l-glutamic acid, and l-lysine on sea sand was carried out. only l-lysine showed adsorption on sea sand, probably due to the presence of the positively charged r group. our results raise some doubts as to whether sand was important for the pre-concentration of amino acids prior to peptide condensation on the pre-biotic earth.
Constru??o de um micrótomo de congelamento a partir da adapta??o de um micrótomo de parafina
Mello, Cesar de;Silva, L.;Zaia, D. A. M.;Zaia, Cassia Thais B. V.;
Brazilian Archives of Biology and Technology , 1998, DOI: 10.1590/S1516-89131998000200013
Abstract: a microtome for frozen sections was developed using the facilities and equipment available in our country. the requirements for making it were: 1) fast frozen of the tissue, 2) easy histological procedure, 3) no necessity of long period for preparation of the tissue for histological procedure, and 4) low cost for making. this study shows results obtained by using the microtome for frozen sections of brain of rats.
Acute morphological and physiological effects of lead in the neotropical fish Prochilodus lineatus
Martinez, C. B. R.;Nagae, M. Y.;Zaia, C. T. B. V.;Zaia, D. A. M.;
Brazilian Journal of Biology , 2004, DOI: 10.1590/S1519-69842004000500009
Abstract: the present study investigated lead effects on gill morphology, hematocrit, blood sodium, glucose, lipids, protein, and cholesterol of prochilodus lineatus exposed to two sublethal lead concentrations for 96 h. preliminary series of short-term static toxicity tests were run to determine lc50 (96 h) of lead in p. lineatus, which was 95 mg pb.l-1. therefore, lead concentrations tested in the sublethal experiments were 24 and 71 mg pb.l-1, which correspond to 25% and 75% of the lc50 (96 h), respectively. gills of p. lineatus exposed to both lead concentrations during 96 h presented a higher occurrence of histopathological lesions such as epithelial lifting, hyperplasia, and lamellar aneurism. p. lineatus did not show significant alterations in hematocrit during exposure to both lead concentrations. fish exposed to the highest lead concentration showed a significant decrease in na+ plasma concentration after 48 h, possibly reflecting a sodium influx rate decrease. p. lineatus exposed to both lead concentrations presented a "classical general adaptation syndrome to stress", as hyperglycemia associated with lowered lipids and proteins was reported. stress-response magnitude was dose-dependent. while the response to the lowest lead concentration might represent adaptation, the highest concentration seems to characterize exhaustion.
Determina??o de proteínas totais via espectrofometria: vantagens e desvantagens dos métodos existentes
Zaia, Dimas A. M.;Zaia, Cássia Tha?s B. V.;Lichtig, Jaim;
Química Nova , 1998, DOI: 10.1590/S0100-40421998000600020
Abstract: spectrophotometric determination of total protein is used in several areas such as clinical analysis, food science and technology, biochemistry, protein chemistry, physiology. five spectrophotometric methods are mostly used: biuret, lowry, bradford, smith and uv absorption. in this review a general overview of these methods is presented (interferences, applications); other methodologies are also discussed.
Adsor??o de aminoácidos sobre minerais e a origem da vida
Zaia, Dimas A. M.;Zaia, Cássia Tha?s B. V.;
Química Nova , 2006, DOI: 10.1590/S0100-40422006000400027
Abstract: minerals adsorb more readily amino acids with charged r groups than those with uncharged r groups, so that the incorporation of amino acids with charged r groups into peptides would be more frequent than that of amino acids with uncharged r groups. however, 74% of the amino acids in the proteins of modern organisms contain uncharged r groups. thus, what could have been the mechanism that produced peptides/proteins with more amino acids with uncharged r groups than precursors with charged r groups? the lipid world offers an alternative view of the origin of life. in the present paper, several other mechanisms are also discussed.
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