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Search Results: 1 - 10 of 225667 matches for " Vincent C. Bond "
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HLA-G DNA sequence variants and risk of perinatal HIV-1 transmission
Felix O Aikhionbare, K Kumaresan, Falah Shamsa, Vincent C Bond
AIDS Research and Therapy , 2006, DOI: 10.1186/1742-6405-3-28
Abstract: Genomic DNA samples were obtained from a nested case-control study of 34 mother-child pairs co-enrolled in a cohort of the Perinatal AIDS Collaborative Transmission Study in New York. The samples were from two groups predominantly of African-American and Hispanic origin: In the first group, both mother and child were HIV-1-infected; in the second group, only the mother was infected while the child remained uninfected. Genotyping of HLA-G gene were performed on the extracted DNA from peripheral blood mononuclear cells using PCR based sequencing and restriction fragment-length polymorphism analyses.Among the studied HLA-G exons, dissimilarities in HLA-G DNA sequence variants between the HIV-1 non-transmitting mother child pairs were mostly observed in exon 8-3'-untranslated region at nucleotide positions T3742A, C3743T, G3777C (P = 0.001). Non-transmitting HIV-1 mother child pairs exhibited dissimilarities at nucleotide position C3743T allele with decreased risk of perinatal HIV-1 transmission, compared with HIV-1 transmitting mother-child pairs carrying this allele (odds ratio 0.02 [95% confidence interval 0.00–0.15] P = 0.00001). In addition, heterozygous dissimilarities at nucleotide positions C634G and 714 insT/G in the 5'-upstream regulatory region were observed between the mother child pairs of the HIV-1-non-transmitting group while homozygous similarities of C634C, and either 714insG/G or mother-child pairs with similar 714insT/G were observed among the transmitting group in the same region.This study identified new variants in the HLA-G gene and provides further evidence that dissimilarities in the HLA-G DNA sequence variants could influence the transmission of HIV-1 from infected mothers to their infants.Mother-to-child HIV transmission (MTCT) can occur during pregnancy, labor and postnatally through breastfeeding [1,2]. In developed countries, MTCT has decreased to approximately 1 or 2% after implementation of universal prenatal HIV counseling and testing, a
Plasmodium berghei ANKA infection increases Foxp3, IL-10 and IL-2 in CXCL-10 deficient C57BL/6 mice
Bismark Y Sarfo, Nana O Wilson, Vincent C Bond, Jonathan K Stiles
Malaria Journal , 2011, DOI: 10.1186/1475-2875-10-69
Abstract: The hypothesis that resistance of CXCL-10-/- mice to murine CM may be due to enhanced expression of Foxp3 in concert with IL-10 and IL-2 was tested. CXCL-10-/- and WT C57BL/6 mice were infected with Plasmodium berghei ANKA and evaluated for CM symptoms. Brain, peripheral blood mononuclear cells (PBMCs) and plasma were harvested from infected and uninfected mice at days 2, 4 and 8. Regulatory T cells (CD4+CD25+) and non-T regs (CD4+CD25-) were isolated from PBMCs and cultured with P. berghei antigens in vitro with dendritic cells as antigen presenting cells. Regulatory T cell transcription and specific factor Foxp3, was evaluated in mouse brain and PBMCs by realtime-PCR and Western blots while IL-10, and IL-2 were evaluated in plasma and cultured supernatants by ELISA.Wild type mice exhibited severe murine CM symptoms compared with CXCL-10-/- mice. Foxp3 mRNA and protein in brain and PBMC's of CXCL-10-/- mice was significantly up-regulated (p < 0.05) by day 4 post-infection (p.i) compared with WT. Plasma levels of IL-10 and IL-2 in infected CXCL-10-/- were higher than in WT mice (p < 0.05) at days 2 and 4 p.i. Ex-vivo CD4+CD25+ T cells from CXCL-10-/- re-stimulated with P. berghei antigens produced more IL-10 than WT CD4+CD25+ T cells.The results indicate that in the absence of CXCL-10, the resulting up-regulation of Foxp3, IL-10 and IL-2 may be involved in attenuating fatal murine CM.Cerebral malaria (CM) is a major cause of malaria mortality in endemic countries. The current paradigm of CM pathogenesis suggests that parasite proliferation activates endothelial cells to produce adhesion molecules that enable sequestration of infected and uninfected red blood cells (RBCs) in brain capillaries which obstruct brain microvessels which results in severe inflammatory processes that lead to CM syndrome. Recently it has been reported that regulatory inflammatory responses are associated with CM but the mechanism by which they regulate CM pathogenesis is unclear. For example
Functionally-Impaired HIV-1 Nef Alleles from a Mother-Child Transmission Pair
William W. Roth,Mafhuz Khan,Romas Geleziunas,Harold G. Stringer,Jalal A. Zuberi,Warner C. Greene,Michael Powell,Vincent C. Bond
International Journal of Molecular Sciences , 2002, DOI: 10.3390/i3101058
Abstract: Unusual HIV-1 nef alleles were isolated from a woman and her vertically infected child. Both patients eventually progressed to develop AIDS. The child died at age 6.5 years, while the mother is currently alive, 13 years since her diagnosis with HIV-1. Predicted amino acid sequences of both mother and child Nefs diverged from the HIV-1 clade B consensus. In particular, they exhibited two separate 5-amino acid deletions bracketing a Cterminal dileucine regulatory motif and Trp-Gly mutations at the site for cleavage by the HIV-1 protease. The child’s Nef showed a modest ability to enhance HIV-1 infectivity in MAGI cells, whereas the mother’s Nef did not alter HIV-1 infectivity in the assay. Both Nefs were partially functional for CD4 down-regulation. The child’s Nef was fully functional for MHC-1 down-regulation, while the maternal Nef was non-functional. To our knowledge this study is the first to describe a functional divergence between Nef alleles in a case of mother-to-child HIV-1 transmission.
Nef-M1, a CXCR4 Peptide Antagonist, Enhances Apoptosis and Inhibits Primary Tumor Growth and Metastasis in Breast Cancer  [PDF]
Harvey Bumpers, Ming-Bo Huang, Venkat Katkoori, Upender Manne, Vincent Bond
Journal of Cancer Therapy (JCT) , 2013, DOI: 10.4236/jct.2013.44101
Abstract:

Results from studies with animal models suggest that, in many cancers, CXCR4 is an important therapeutic target and that CXCR4 antagonists may be promising treatments for primary cancers and for metastases. The Nef protein effectively competes with CXCR4’s natural ligand, SDF-1α, and induces apoptosis. As described in this report, the Nef-M1 peptide (Nef protein amino acids 50 - 60) inhibits primary tumor growth and metastasis of breast cancer (BC). Four BC cell lines (MDA-MB-231, MDA-MB-468, MCF 7, and DU4475) and primary human mammary epithelium (HME) cells were evaluated for their response to the Nef protein and to the Nef-M1 peptide. The presence of CXCR4 receptors in these cells was determined by RT-PCR, Western blot (WB), and immunohistochemical analyses. The apoptotic effect of Nef-M1 was assessed by terminal transferase dUTP nick-end labeling (TUNEL). WBs was used to assess caspase 3 activation. BC xenografts grown in SCID mice were evaluated for the presence of CXCR4 and for their metastatic potential. CXCR4 was presented in MDA-MB-231, MCF 7, and DU 4475 BC cells but not in MDA-MB-468 BC or HME cells. Cells expressing CXCR4 and treated with Nef-M1 peptide or the Nef protein had higher rates of apoptosis than untreated cells. Caspase-3 activation increased in MDA-MB 231 cells treated with the Nef protein, the Nef 41 - 60 peptide, or Nef-M1. Nef-M1, administered to mice starting at the time of xenograft implantation, inhibited growth of primary tumors and metastatic spread. Untreated mice developed diffuse intraperitoneal metastases. We conclude that, in BCs, Nef-M1, through interaction with CXCR4, inhibits primary tumor growth and metastasis by causing apoptosis.

Chemisorption and Reactions of Small Molecules on Small Gold Particles
Geoffrey C. Bond
Molecules , 2012, DOI: 10.3390/molecules17021716
Abstract: The activity of supported gold particles for a number of oxidations and hydrogenations starts to increase dramatically as the size falls below ~3 nm. This is accompanied by an increased propensity to chemisorption, especially of oxygen and hydrogen. The explanation for these phenomena has to be sought in kinetic analysis that connects catalytic activity with the strength and extent of chemisorption of the reactants, the latter depending on the electronic structure of the gold atoms constituting the active centre. Examination of the changes to the utilisation of electrons as particle size is decreased points to loss of metallic character at about 3 nm, as energy bands are replaced by levels, and a band gap appears. Detailed consideration of the Arrhenius parameters (E and ln A) for CO oxidation points clearly to a step-change in activity at the point where metallic character is lost, as opposed to there being a monotonic dependence of rate on a physical property such as the fraction of atoms at corners or edges of particles. The deplorable scarcity of kinetic information on other reactions makes extension of this analysis difficult, but non-metallic behaviour is an unavoidable property of very small gold particles, and therefore cannot be ignored when seeking to explain their exceptional activity.
Gold: A relatively new catalyst
Geoffrey C Bond
Gold Bulletin , 2001, DOI: 10.1007/BF03214823
Abstract: Work performed with gold catalysts before about 1980 is briefly reviewed, and early indications of the importance of using very small particles to obtain good activity are noted. The apparent contrast between silver and gold in catalysing carbon monoxide oxidation was anticipated by studies in matrix isolation chemistry. The unexpected and in some ways unique properties of gold are attributable to the operation of a relativistic effect which stabilises the 6s 2 electron pair. Essential requirements for high oxidation activity include: small particle size, use of ‘reactive’ support, and a preparative method that achieves the desired size of particle in intimate contact with the support. Surface atoms on such small particles behave more like individual atoms, and this together with awareness of the relativistic factor may help to explain why gold can be such an effective catalyst.
The catalytic properties of gold
G. C. Bond
Gold Bulletin , 1972, DOI: 10.1007/BF03215149
Abstract: Although the catalytic properties of gold are surpassed by those of the Group VIII metals, especially palladium and platinum, possible applications of gold in catalytic processes have been widely studied, more especially for oxidative dehydrogenation. Alloys and mixtures of gold with the platinum group metals are also receiving increased attention, and the developments outlined here indicate a number of potential uses.
Guest Editorial
Geoffrey C Bond
Gold Bulletin , 1998, DOI: 10.1007/BF03214774
Abstract:
Cerebrospinal fluid and serum biomarkers of cerebral malaria mortality in Ghanaian children
Henry B Armah, Nana O Wilson, Bismark Y Sarfo, Michael D Powell, Vincent C Bond, Winston Anderson, Andrew A Adjei, Richard K Gyasi, Yao Tettey, Edwin K Wiredu, Jon Tongren, Venkatachalam Udhayakumar, Jonathan K Stiles
Malaria Journal , 2007, DOI: 10.1186/1475-2875-6-147
Abstract: Postmortem serum and cerebrospinal fluid (CSF) samples were obtained within 2–4 hours of death in Ghanaian children dying of CM, severe malarial anemia (SMA), and non-malarial (NM) causes. Serum and CSF levels of 36 different biomarkers (IL-1β, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12 (p70), IL-13, IL-15, IL-17, Eotaxin, FGF basic protein, CRP, G-CSF, GM-CSF, IFN-γ, TNF-α, IP-10, MCP-1 (MCAF), MIP-1α, MIP-1β, RANTES, SDF-1α, CXCL11 (I-TAC), Fas-ligand [Fas-L], soluble Fas [sFas], sTNF-R1 (p55), sTNF-R2 (p75), MMP-9, TGF-β1, PDGF bb and VEGF) were measured and the results compared between the 3 groups.After Bonferroni adjustment for other biomarkers, IP-10 was the only serum biomarker independently associated with CM mortality when compared to SMA and NM deaths. Eight CSF biomarkers (IL-1ra, IL-8, IP-10, PDGFbb, MIP-1β, Fas-L, sTNF-R1, and sTNF-R2) were significantly elevated in CM mortality group when compared to SMA and NM deaths. Additionally, CSF IP-10/PDGFbb median ratio was statistically significantly higher in the CM group compared to SMA and NM groups.The parasite-induced local cerebral dysregulation in the production of IP-10, 1L-8, MIP-1β, PDGFbb, IL-1ra, Fas-L, sTNF-R1, and sTNF-R2 may be involved in CM neuropathology, and their immunoassay may have potential utility in predicting mortality in CM.Malaria is an important neglected disease and one of the most important global health problems, potentially affecting more than one third of the world's population. Cerebral malaria (CM) is a deadly complication of Plasmodium falciparum infection, associated with a 10–14% mortality rate and approximately 1–2 million annual deaths among young children predominantly in sub-Saharan Africa and Southeast Asia, yet its pathogenesis remains incompletely understood. In Ghana, malaria has a wide spectrum of presentations: from asymptomatic carriers to mild malaria to multifactorial severe disease, including CM and severe malarial anemia (SMA) [1-5].CM
Characterization of Exosomes in Plasma of Patients with Breast, Ovarian, Prostate, Hepatic, Gastric, Colon, and Pancreatic Cancers  [PDF]
Ming-Bo Huang, Meng Xia, Zhao Gao, Hu Zhou, Min Liu, Shan Huang, Rong Zhen, Jennifer Y. Wu, William W. Roth, Vincent C. Bond, Jian Xiao, Jing Leng
Journal of Cancer Therapy (JCT) , 2019, DOI: 10.4236/jct.2019.105032
Abstract: Detection of circulating tumor-specific DNA, RNA or proteins can be difficult due to relative scarcity. Exosomes are extracellular vesicles, 30 - 150 nm in diameter derived from fusion of multivesicular bodies with the plasma membrane. They are composed of a lipid bilayer membrane and contain proteins, mRNA and miRNA. Exosomes are secreted by multiple cell types, including cancer cells. However, there is a relative lack of information concerning the contents of exosomes secreted by various tumor cell types. To examine exosomes in cancer, we collected blood plasma samples from patients with breast, ovarian, prostate, hepatic, gastric, colon, and pancreatic cancers. Exosomes were isolated from plasma and confirmed by AchE assay, transmission electron microscopy and expression of the CD63 exosomal marker. Expression of AFP, CA724, CA153, CEA, CA125, CA199 and PSA antigens were determined using an automated electro-chemiluminescence assay. Expression of the tumor-related chaperone protein, mortalin, was determined by Western blot analysis. Levels of exosome secretion were variable among the different tumor types. Both exosome levels and mortalin expression within tumor cell exosomes were higher than in healthy donors, except in pancreatic carcinoma, where exosomes were elevated but mortalin expression was not significantly different from healthy donors. Exosomes provide unique opportunities for the enrichment of tumor-specific materials and may be useful as biomarkers and
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