26
|
Fong S, Van Eerden P, Vathy I. Does morphine mitigate effects of prenatal stress on maternal behavior in rats? Am J Obstet Gynecol 2006. [DOI: 10.1016/j.ajog.2006.10.406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
27
|
|
28
|
Liu Y, Liggitt D, Fong S, Debs RJ. Systemic co-administration of depsipeptide selectively targets transfection enhancement to specific tissues and cell types. Gene Ther 2006; 13:1724-30. [PMID: 16886001 DOI: 10.1038/sj.gt.3302825] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Depsipeptide, a histone deacetylase (HDAC) inhibitor, kills tumor cells much more effectively than normal cells, and can produce significant antitumor activity in human cancer patients. Depsipeptide also increases the expression of lipoplex-delivered genes in cultured tumor cells, as well as following direct intra-tumoral injection. We now show that co-intravenous (i.v.) injection of depsipeptide with polyethylenimine (PEI):DNA complexes significantly increases the expression of PEI-delivered genes in normal, as well as in tumor-bearing mice. At the tissue level, depsipeptide-mediated enhancement of gene expression was selectively targeted to the lung, liver and spleen. At the cellular level, depsipeptide significantly increased the expression of the i.v., PEI co-delivered wild-type human p53 gene in metastatic breast cancer cells, but not in adjacent normal cells. Thus, the ability of depsipeptide to enhance the expression of systemically delivered genes is selectively targeted at both the tissue and cellular levels, without requiring the use of ligand- or promoter-based approaches. Analyzing HDAC-based targeting of gene expression may identify host genes that control the expression of systemically delivered genes.
Collapse
|
29
|
Abbas AR, Baldwin D, Ma Y, Ouyang W, Gurney A, Martin F, Fong S, van Lookeren Campagne M, Godowski P, Williams PM, Chan AC, Clark HF. Immune response in silico (IRIS): immune-specific genes identified from a compendium of microarray expression data. Genes Immun 2005; 6:319-31. [PMID: 15789058 DOI: 10.1038/sj.gene.6364173] [Citation(s) in RCA: 286] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Immune cell-specific expression is one indication of the importance of a gene's role in the immune response. We have compiled a compendium of microarray expression data for virtually all human genes from six key immune cell types and their activated and differentiated states. Immune Response In Silico (IRIS) is a collection of genes that have been selected for specific expression in immune cells. The expression pattern of IRIS genes recapitulates the phylogeny of immune cells in terms of the lineages of their differentiation. Gene Ontology assignments for IRIS genes reveal significant involvement in inflammation and immunity. Genes encoding CD antigens, cytokines, integrins and many other gene families playing key roles in the immune response are highly represented. IRIS also includes proteins of unknown function and expressed sequence tags that may not represent genes. The predicted cellular localization of IRIS proteins is evenly distributed between cell surface and intracellular compartments, indicating that immune specificity is important at many points in the signaling pathways of the immune response. IRIS provides a resource for further investigation into the function of the immune system and immune diseases.
Collapse
|
30
|
de Vlaming V, DiGiorgio C, Fong S, Deanovic LA, de la Paz Carpio-Obeso M, Miller JL, Miller MJ, Richard NJ. Irrigation runoff insecticide pollution of rivers in the Imperial Valley, California (USA). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2004; 132:213-29. [PMID: 15312936 DOI: 10.1016/j.envpol.2004.04.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2003] [Accepted: 04/20/2004] [Indexed: 05/13/2023]
Abstract
The Alamo and New Rivers located in the Imperial Valley, California receive large volumes of irrigation runoff and discharge into the ecologically sensitive Salton Sea. Between 1993 and 2002 we conducted a series of studies to assess water quality using three aquatic species: a cladoceran (Ceriodaphnia dubia), a mysid (Neomysis mercedis), and a larval fish (Pimephales promelas). Although no mortality was observed with the P. promelas, high-level toxicity to the invertebrate species was documented in samples from both rivers during many months of each year. Toxicity identifications and chemical analyses identified the organophosphorus insecticides (OP), chlorpyrifos and diazinon, as the cause of C. dubia toxicity. The extent of the C. dubia mortality was highly correlated with quantities of these OPs applied in the river watersheds. C. dubia mortality occurred during more months of our 2001/2002 study than in the 1990s investigations. During 2001/2002, the extensive C. dubia mortality observed in New River samples was caused by OP insecticide pollution that originated from Mexico. Mortality to N. mercedis in New River samples was likely caused by contaminants other than OP insecticides. Our studies document OP insecticide-caused pollution of the Alamo River over a 10-year period and provide the necessary information for remediation efforts.
Collapse
|
31
|
de Vlaming V, DiGiorgio C, Fong S, Deanovic LA, de la Paz Carpio-Obeso M, Miller JL, Miller MJ, Richard NJ. Irrigation runoff insecticide pollution of rivers in the Imperial Valley, California (USA). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2004; 132:213-229. [PMID: 15312936 DOI: 10.106/j.envpol.2004.04.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/14/2003] [Accepted: 04/20/2004] [Indexed: 05/27/2023]
Abstract
The Alamo and New Rivers located in the Imperial Valley, California receive large volumes of irrigation runoff and discharge into the ecologically sensitive Salton Sea. Between 1993 and 2002 we conducted a series of studies to assess water quality using three aquatic species: a cladoceran (Ceriodaphnia dubia), a mysid (Neomysis mercedis), and a larval fish (Pimephales promelas). Although no mortality was observed with the P. promelas, high-level toxicity to the invertebrate species was documented in samples from both rivers during many months of each year. Toxicity identifications and chemical analyses identified the organophosphorus insecticides (OP), chlorpyrifos and diazinon, as the cause of C. dubia toxicity. The extent of the C. dubia mortality was highly correlated with quantities of these OPs applied in the river watersheds. C. dubia mortality occurred during more months of our 2001/2002 study than in the 1990s investigations. During 2001/2002, the extensive C. dubia mortality observed in New River samples was caused by OP insecticide pollution that originated from Mexico. Mortality to N. mercedis in New River samples was likely caused by contaminants other than OP insecticides. Our studies document OP insecticide-caused pollution of the Alamo River over a 10-year period and provide the necessary information for remediation efforts.
Collapse
|
32
|
Kline T, Andersen NH, Harwood EA, Bowman J, Malanda A, Endsley S, Erwin AL, Doyle M, Fong S, Harris AL, Mendelsohn B, Mdluli K, Raetz CRH, Stover CK, Witte PR, Yabannavar A, Zhu S. Potent, novel in vitro inhibitors of the Pseudomonas aeruginosa deacetylase LpxC. J Med Chem 2002; 45:3112-29. [PMID: 12086497 DOI: 10.1021/jm010579r] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Deacetylation of uridyldiphospho-3-O-(R-hydroxydecanoyl)-N-acetylglucosamine by LpxC is the first committed step in the Pseudomonas aeruginosa biosynthetic pathway to lipid A; homologous enzymes are found widely among Gram-negative bacteria. As an essential enzyme for which no inhibitors have yet been reported, the P. aeruginosa LpxC represents a highly attractive target for a novel antibacterial drug. We synthesized several focused small-molecule libraries, each composed of a variable aromatic ring, one of four heterocyclic/spacer moieties, and a hydroxamic acid and evaluated the LpxC inhibition of these compounds against purified P. aeruginosa enzyme. To ensure that the in vitro assay would be as physiologically relevant as possible, we synthesized a tritiated form of the specific P. aeruginosa glycolipid substrate and measured directly the enzymatically released acetate. Several of our novel compounds, predominantly those having fluorinated substituents on the aromatic ring and an oxazoline as the heterocyclic moiety, demonstrated in vitro IC(50) values less than 1 microM. We now report the synthesis and in vitro evaluation of these P. aeruginosa LpxC inhibitors.
Collapse
|
33
|
Fong S, Doyle MV, Goodson RJ, Drummond RJ, Stratton JR, McGuire L, Doyle LV, Chapman HA, Rosenberg S. Random peptide bacteriophage display as a probe for urokinase receptor ligands. Biol Chem 2002; 383:149-58. [PMID: 11928809 DOI: 10.1515/bc.2002.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The urokinase receptor is a multi-functional protein that plays a central role in cell surface plasminogen activation, cell migration, and cell adhesion. We previously demonstrated that high affinity peptide ligands for the urokinase receptor, which are urokinase competitors, can be obtained from a 15mer peptide library (Goodson et al., 1994). In order to probe for additional urokinase receptor binding sites we affinity selected the same bacteriophage library on complexes of soluble urokinase receptor (suPAR) and the receptor binding domain of urokinase, residues 1-48 (uPA1-48). Bacteriophage were isolated which bound to suPAR and suPAR:uPA1-48 complexes with high yield. The peptide sequences encoded by these bacteriophage were distinct from those obtained previously on urokinase receptor expressing cells, and comprise two groups based upon effects on su-PAR:1-anilino-8-napthalene sulfonate (ANS) fluorescence, and vitronectin binding competition. Alanine scanning mutagensis of the soluble peptides was used to define minimal regions and key residues for suPAR binding by competition with the parent bacteriophage. A comparison of these results with sequences of domains of both vitronectin and integrin alpha-chains, which have been reported to be important for urokinase receptor binding, suggests that the homology with the peptide sequences selected is functionally significant.
Collapse
|
34
|
Green MJ, Fong S, Mauger DT, Ubel PA. Rationing HIV medications: what do patients and the public think about allocation policies? J Acquir Immune Defic Syndr 2001; 26:56-62. [PMID: 11176269 DOI: 10.1097/00126334-200101010-00008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND New medications for treating HIV/AIDS are effective, but expensive, and funding shortfalls have led many state AIDS Drug Assistance Programs (ADAPs) to ration these drugs. Little is known about the views of those most directly affected by rationing policies. This study explores attitudes of patients with HIV and the general public toward specific rationing strategies. METHODS A Likert-style, self-administered questionnaire about rationing expensive HIV medications in the context of a budget shortfall was administered to patients with HIV and shopping mall patrons in central Pennsylvania. Subjects were asked how much they agreed or disagreed with seven drug rationing policies. RESULTS In all, 100 patients and 101 shoppers completed the survey (response rate = 89%). A majority in both groups "strongly" or "somewhat" disagreed with six of the seven rationing policies described, and patients more strongly disagreed with the policies than did the public. The five policies actually used by state ADAPs (first come first serve, limiting expensive medicines, limiting new patient enrollment, giving the expensive medicines to the sickest, using a spending cap) lacked support in either group. CONCLUSIONS HIV drug rationing policies currently in use do not reflect the preferences of patients and the public. Integrating the views of those affected by the rationing decisions would raise difficult challenges to current programs.
Collapse
|
35
|
Pender SL, Salmela MT, Monteleone G, Schnapp D, McKenzie C, Spencer J, Fong S, Saarialho-Kere U, MacDonald TT. Ligation of alpha4ss1 integrin on human intestinal mucosal mesenchymal cells selectively Up-regulates membrane type-1 matrix metalloproteinase and confers a migratory phenotype. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 157:1955-62. [PMID: 11106568 PMCID: PMC1885781 DOI: 10.1016/s0002-9440(10)64834-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Human intestinal lamina propria mesenchymal cells show high surface expression of the alpha4ss1 integrin. Ligation of alpha4ss1 on mesenchymal cell lines with an activating monoclonal anti-alpha4 antibody or vascular cell adhesion molecule-immunoglobulin (VCAM-IgG) leads to the appearance of activated forms of gelatinase A in culture supernatants, and the de novo expression of activated membrane type-1-matrix metalloproteinase (MT1-MMP). In functional assays, signaling through alpha4ss1 results in an increased capacity of mesenchymal cells to migrate through an artificial extracellular matrix, an effect inhibitable by excess tissue inhibitor of metalloproteinase-2. In organ cultures of human intestine, VCAM-IgG also up-regulates MT1-MMP, and in mucosal ulcers of inflammatory bowel disease patients, MT1-MMP transcripts are abundant, coincident with expression of VCAM-1 on cells at the ulcer margin. Collectively these results suggest that alpha4ss1-induced up-regulation of MT1-MMP may be a crucial factor in the migration of mesenchymal cells into ulcer beds during restitution of diseased gut mucosa.
Collapse
|
36
|
Liang TW, DeMarco RA, Mrsny RJ, Gurney A, Gray A, Hooley J, Aaron HL, Huang A, Klassen T, Tumas DB, Fong S. Characterization of huJAM: evidence for involvement in cell-cell contact and tight junction regulation. Am J Physiol Cell Physiol 2000; 279:C1733-43. [PMID: 11078687 DOI: 10.1152/ajpcell.2000.279.6.c1733] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cell-cell interactions of the mucosal epithelia are important for the maintenance and establishment of epithelial barrier function. During events of inflammation, such cell-cell interactions are often disrupted, resulting in a leaky epithelial barrier, which in turn can lead to various inflammatory and infective dysfunctions. Human junctional adhesion molecule (huJAM), found on the mucosal epithelia and vascular endothelia of many major organ systems, is a membrane glycoprotein which resolves to a doublet band of approximately 40 and approximately 37 kDa under SDS-PAGE analysis, representing differentially glycosylated forms of the same protein. huJAM was localized to the lateral membrane of Caco-2 cells (a human colonic epithelial cell line) monolayers, in an area basolateral of the epithelial tight junctions (TJ). Through functional and biochemical assays, we show huJAM to be able to homotypically associate and to participate in TJ restitution after trypsin-EDTA disruption. Furthermore, we also observed a migration of huJAM expression toward areas of cell-cell contacts during events of cell adhesion and monolayer formation. These qualities makes huJAM a likely player in the regulation of cell-cell contacts and the subsequent formation of TJs.
Collapse
|
37
|
Fong S, Machajewski TD, Mak CC, Wong C. Directed evolution of D-2-keto-3-deoxy-6-phosphogluconate aldolase to new variants for the efficient synthesis of D- and L-sugars. CHEMISTRY & BIOLOGY 2000; 7:873-83. [PMID: 11094340 DOI: 10.1016/s1074-5521(00)00035-1] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Exploitation and improvement of enzymes as catalysts for organic synthesis is of current interest in biocatalysis. A representative enzyme for investigation is the Escherichia coli D-2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase, which catalyzes the highly specific reversible aldol reaction using the D-configurated KDPG as substrate. RESULTS Using in vitro evolution, the aldolase has been converted into aldolases with improved catalytic efficiency, altered substrate specificity and stereoselectivity. In particular, some evolved aldolases capable of accepting both D- and L- glyceraldehyde in the non-phosphorylated form as substrates for reversible aldol reaction have been obtained, providing a new direction to the enzymatic synthesis of both D- and L-sugars. CONCLUSIONS This research has demonstrated the effectiveness of using in vitro evolution to rapidly alter the properties of an aldolase to improve its utility in asymmetric synthesis. The evolved aldolases, differing from the native enzyme which is highly phosphate- and D-sugar-dependent, catalyze the efficient synthesis of both D- and L-sugars from non-phosphorylated aldehydes and pyruvate. The principles and strategies described in this study should be applicable to other aldolases to further expand the scope of their synthetic utility.
Collapse
|
38
|
Campbell M, Buckeridge D, Dwyer J, Fong S, Mann V, Sanchez-Sweatman O, Stevens A, Fung L. A systematic review of the effectiveness of environmental awareness interventions. Canadian Journal of Public Health 2000. [PMID: 10832181 DOI: 10.1007/bf03404930] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To evaluate and summarize evidence on the effectiveness of interventions available to public health staff regarding the protection of the public from environmental risks. METHOD This systematic review involved a comprehensive literature search, screening for relevance, quality assessment of relevant studies, data extraction and synthesis. RESULTS Fourteen of 65 relevant studies were of 'moderate' or 'strong' quality. Intervention types in these 14 studies included: mass campaign, counselling, school curriculum, educational sessions, and distribution of printed materials. Short-term improvements in awareness or knowledge were observed in 13 of the 14 studies. Eight of 13 studies that examined behavioural outcomes observed short-term improvements in self-reported behavioural outcomes. CONCLUSIONS Positive short-term changes in health-protective awareness, knowledge and self-reported behaviour appear to be associated with relatively intensive interventions that use multiple methods and settings, and/or are delivered over multiple sessions.
Collapse
|
39
|
Quan C, Skelton NJ, Clark K, Jackson DY, Renz ME, Chiu HH, Keating SM, Beresini MH, Fong S, Artis DR. Transfer of a protein binding epitope to a minimal designed peptide. Biopolymers 2000; 47:265-75. [PMID: 10036968 DOI: 10.1002/(sici)1097-0282(1998)47:4<265::aid-bip2>3.0.co;2-k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Results from protein mutagenesis and x-ray crystallographic studies of the multidomain protein Vascular Cell Adhesion Molecule (VCAM) were used to design cyclic octapeptides that retain the critical structural and binding elements of the epitope of VCAM in the interaction with the integrin alpha 4 beta 1 (VLA-4). Changes in the activities of peptide analogues correlated with the relative activities of protein mutants of VCAM, and predicted the properties of two new mutants that bound alpha 4 beta 1 with improved affinity vs wild type protein. The nmr structures of two peptides revealed a high degree of similarity to the structure of the VCAM binding epitope. These results demonstrate that a compact binding epitope identified via protein structure-function studies may be transferred to a synthetically accessible small peptide with the key structure-activity relationships intact.
Collapse
|
40
|
Campbell M, Buckeridge D, Dwyer J, Fong S, Mann V, Sanchez-Sweatman O, Stevens A, Fung L. A systematic review of the effectiveness of environmental awareness interventions. CANADIAN JOURNAL OF PUBLIC HEALTH = REVUE CANADIENNE DE SANTE PUBLIQUE 2000; 91:137-43. [PMID: 10832181 PMCID: PMC6979961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/17/1999] [Accepted: 10/26/1999] [Indexed: 02/16/2023]
Abstract
PURPOSE To evaluate and summarize evidence on the effectiveness of interventions available to public health staff regarding the protection of the public from environmental risks. METHOD This systematic review involved a comprehensive literature search, screening for relevance, quality assessment of relevant studies, data extraction and synthesis. RESULTS Fourteen of 65 relevant studies were of 'moderate' or 'strong' quality. Intervention types in these 14 studies included: mass campaign, counselling, school curriculum, educational sessions, and distribution of printed materials. Short-term improvements in awareness or knowledge were observed in 13 of the 14 studies. Eight of 13 studies that examined behavioural outcomes observed short-term improvements in self-reported behavioural outcomes. CONCLUSIONS Positive short-term changes in health-protective awareness, knowledge and self-reported behaviour appear to be associated with relatively intensive interventions that use multiple methods and settings, and/or are delivered over multiple sessions.
Collapse
|
41
|
Chen H, He J, Fong S, Wilcox G, Wood C. Jembrana disease virus Tat can regulate human immunodeficiency virus (HIV) long terminal repeat-directed gene expression and can substitute for HIV Tat in viral replication. J Virol 2000; 74:2703-13. [PMID: 10684286 PMCID: PMC111760 DOI: 10.1128/jvi.74.6.2703-2713.2000] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Jembrana disease virus (JDV) is a bovine lentivirus genetically similar to bovine immunodeficiency virus; it causes an acute and sometimes fatal disease in infected animals. This virus carries a very potent Tat that can strongly activate not only its own long terminal repeat (LTR) but also the human immunodeficiency virus (HIV) LTR. In contrast, HIV Tat cannot reciprocally activate the JDV LTR (H. Chen, G. E. Wilcox, G. Kertayadnya, and C. Wood, J. Virol. 73:658-666, 1999). This indicates that in transactivation JDV Tat may utilize a mechanism similar to but not the same as that of the HIV Tat. To further study the similarity of JDV and HIV tat in transactivation, we first tested the responses of a series of HIV LTR mutants to the JDV Tat. Cross-transactivation of HIV LTR by JDV Tat was impaired by mutations that disrupted the HIV type 1 transactivation response element (TAR) RNA stem-loop structure. Our results demonstrated that JDV Tat, like HIV Tat, transactivated the HIV LTR at least partially in a TAR-dependent manner. However, the sequence in the loop region of TAR was not as critical for the function of JDV Tat as it was for HIV Tat. The competitive inhibition of Tat-induced transactivation by the truncated JDV or HIV Tat, which consisted only of the activation domain, suggested that similar cellular factors were involved in both JDV and HIV Tat-induced transactivation. Based on the one-round transfection assay with HIV tat mutant proviruses, the cotransfected JDV tat plasmid can functionally complement the HIV tat defect. To further characterize the effect of JDV Tat on HIV, a stable chimeric HIV carrying the JDV tat gene was generated. This chimeric HIV replicated in a T-cell line, C8166, and in peripheral blood mononuclear cells, which suggested that JDV Tat can functionally substitute for HIV Tat. Further characterization of this chimeric virus will help to elucidate how JDV Tat functions and to explain the differences between HIV and JDV Tat transactivation.
Collapse
MESH Headings
- Animals
- Base Sequence
- Binding Sites
- Binding, Competitive
- Cattle
- Cells, Cultured
- Gene Expression
- Gene Expression Regulation, Viral
- Gene Products, tat/classification
- Gene Products, tat/genetics
- Gene Products, tat/metabolism
- Genetic Complementation Test
- HIV Long Terminal Repeat
- HIV-1/genetics
- HIV-1/physiology
- Humans
- Lentiviruses, Bovine/genetics
- Leukocytes, Mononuclear/cytology
- Molecular Sequence Data
- Nucleic Acid Conformation
- Phylogeny
- Proviruses/genetics
- RNA, Viral
- Transcriptional Activation
- Virus Replication/physiology
- tat Gene Products, Human Immunodeficiency Virus
Collapse
|
42
|
|
43
|
Duffy JA, Ingram MD, Fong S. Effect of basicity on chemical bonding of metal ions in glass and its relevance to their stability. Phys Chem Chem Phys 2000. [DOI: 10.1039/b000489h] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
44
|
Hillan KJ, Hagler KE, MacSween RN, Ryan AM, Renz ME, Chiu HH, Ferrier RK, Bird GL, Dhillon AP, Ferrell LD, Fong S. Expression of the mucosal vascular addressin, MAdCAM-1, in inflammatory liver disease. LIVER 1999; 19:509-18. [PMID: 10661685 DOI: 10.1111/j.1478-3231.1999.tb00084.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
AIMS/BACKGROUND The integrin alpha4beta7 and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) are involved in normal recirculation of lymphocytes between the blood and the tissues of the gastrointestinal tract. In this study we have examined the expression of MAdCAM-1 in human liver. METHODS MAdCAM-1 expression was determined in archival human liver tissues by immunohistochemistry. RESULTS While MAdCAM-1 was not detected in normal fetal or adult human liver, expression was observed in association with portal tract inflammation in a variety of liver diseases. Detailed analysis of liver biopsies from patients with hepatitis C showed a positive correlation between the portal/periportal component of the histological activity index (HAI) grade and the presence or absence of MAdCAM-1 expression. CONCLUSION MAdCAM-1 expression may be important in the recruitment of lymphocytes to the liver during inflammation.
Collapse
|
45
|
Ashkenazi A, Pai RC, Fong S, Leung S, Lawrence DA, Marsters SA, Blackie C, Chang L, McMurtrey AE, Hebert A, DeForge L, Koumenis IL, Lewis D, Harris L, Bussiere J, Koeppen H, Shahrokh Z, Schwall RH. Safety and antitumor activity of recombinant soluble Apo2 ligand. J Clin Invest 1999; 104:155-62. [PMID: 10411544 PMCID: PMC408479 DOI: 10.1172/jci6926] [Citation(s) in RCA: 1709] [Impact Index Per Article: 68.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
TNF and Fas ligand induce apoptosis in tumor cells; however, their severe toxicity toward normal tissues hampers their application to cancer therapy. Apo2 ligand (Apo2L, or TRAIL) is a related molecule that triggers tumor cell apoptosis. Apo2L mRNA is expressed in many tissues, suggesting that the ligand may be nontoxic to normal cells. To investigate Apo2L's therapeutic potential, we generated in bacteria a potently active soluble version of the native human protein. Several normal cell types were resistant in vitro to apoptosis induction by Apo2L. Repeated intravenous injections of Apo2L in nonhuman primates did not cause detectable toxicity to tissues and organs examined. Apo2L exerted cytostatic or cytotoxic effects in vitro on 32 of 39 cell lines from colon, lung, breast, kidney, brain, and skin cancer. Treatment of athymic mice with Apo2L shortly after tumor xenograft injection markedly reduced tumor incidence. Apo2L treatment of mice bearing solid tumors induced tumor cell apoptosis, suppressed tumor progression, and improved survival. Apo2L cooperated synergistically with the chemotherapeutic drugs 5-fluorouracil or CPT-11, causing substantial tumor regression or complete tumor ablation. Thus, Apo2L may have potent anticancer activity without significant toxicity toward normal tissues.
Collapse
|
46
|
Tressler RJ, Pitot PA, Stratton JR, Forrest LD, Zhuo S, Drummond RJ, Fong S, Doyle MV, Doyle LV, Min HY, Rosenberg S. Urokinase receptor antagonists: discovery and application to in vivo models of tumor growth. APMIS 1999; 107:168-73. [PMID: 10190294 DOI: 10.1111/j.1699-0463.1999.tb01540.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Urokinase receptor antagonists based on the growth factor domains of both human and murine urokinase which show sub-nanomolar affinities for their homologous receptors have been expressed as recombinant proteins. Further modification of these molecules by preparing fusions with the constant region of human IgG has led to molecules with high affinities and long in vivo half-lives. Smaller peptidic inhibitors have been obtained by a combination of bacteriophage display and peptide analog synthesis. All of these molecules inhibit the binding of the growth factor domain of uPA to the uPA receptor and enhance binding of the uPA receptor to vitronectin. Protein uPA receptor antagonists were tested in an in vivo tumor model using the human breast carcinoma MDAmb231 in immunodeficient mice. Both human and murine receptor antagonists showed significant inhibition of primary tumor growth, demonstrating that in vivo, both tumor and stromal cell uPA receptor dependent plasminogen activation can modulate tumor growth.
Collapse
|
47
|
Bradley LM, Malo ME, Fong S, Tonkonogy SL, Watson SR. Blockade of both L-selectin and alpha4 integrins abrogates naive CD4 cell trafficking and responses in gut-associated lymphoid organs. Int Immunol 1998; 10:961-8. [PMID: 9701034 DOI: 10.1093/intimm/10.7.961] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The recirculation of naive lymphocytes from blood to lymph that is initiated in high endothelial venules (HEV) of secondary lymphoid organs such as lymph nodes and Peyer's patches (PP) is regulated by multiple interactions of adhesion receptor/counter-receptor pairs involving both selectins and integrins. We showed previously that blocking of only L-selectin is sufficient to ablate trafficking of naive CD4 cells and the development of their responses in peripheral lymph nodes but not in PP where alpha4beta7 integrins are thought to primarily regulate entry. However, although antibody to alpha4 integrins partially inhibited homing of naive CD4 cells to PP and not to lymph nodes, there was no effect on the development primary responses in these tissues or spleens. Since previous studies indicate that both alpha4beta7 integrins and L-selectin regulate adhesion of naive cells to PP HEV, we examined the effect a blockade of both adhesion pathways on the recirculation of naive CD4 cells. There was no detectable homing of naive CD4 cells to PP or lymph nodes when interactions with both receptors were inhibited, resulting in a profound depletion of naive CD4 cells and loss of antigen responses in these sites. In contrast, increased numbers of naive CD4 cells and responses of higher magnitude were found in the spleen. The results demonstrate recirculation of naive CD4 cells through tissues where entry is controlled through HEV is essential for the local generation of primary responses.
Collapse
|
48
|
Fong S, Bycroft M, Clarke J, Freund SM. Characterisation of urea-denatured states of an immunoglobulin superfamily domain by heteronuclear NMR. J Mol Biol 1998; 278:417-29. [PMID: 9571061 DOI: 10.1006/jmbi.1998.1702] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The structural and dynamic properties of an immunoglobulin superfamily domain (IgSF), Ig 18', have been characterised by NMR at 285 K, in the presence of 4.2 M and 6.0 M urea, respectively. Analysis of chemical shift deviations, 3JHNHalpha coupling constants, sequential NOE pattern, and 15N relaxation data reveals that although the two urea-denatured states are highly disordered, some local turn-like residual structures do exist. Moreover, some distinct differences between the properties of the two denatured states are observed. In 4.2 M urea-denatured Ig 18', regions 80-83 and 86-92 adopt turn-like conformations, furthermore, region 84-93 is involved in slow exchange processes that occur on a micro- to millisecond time-scale. In the 6.0 M urea-denatured state, these turn-like conformations are less occupied, and chemical exchange processes in region 84-93 are largely reduced. In contrast, region 32-36 has persistent turn-like structures in both urea-denatured states. Some correlation between the spectral density function at 0 frequency, Jeff(0), for the urea-denatured states and the secondary structure elements of the folded state have been observed. Except for the terminal regions, residues corresponding to beta-strands have higher Jeff(0) values compared to residues corresponding to loops. The characterisation and comparison of the two urea-denatured states highlight residues that possess properties that may be crucial for the initiation of folding of this domain.
Collapse
|
49
|
Lee S, Wing YK, Fong S. A controlled study of folate levels in Chinese inpatients with major depression in Hong Kong. J Affect Disord 1998; 49:73-7. [PMID: 9574862 DOI: 10.1016/s0165-0327(97)00200-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Although Western and, in particular, British studies have revealed a substantial rate of hypofolatemia in patients with depression, few such studies have been conducted in Asian populations. METHODS A group of 117 newly admitted inpatients with DSM-III-R major depression and 72 healthy controls underwent blood investigations and psychometric assessments. RESULTS Patients had a significantly lower mean serum folate level (24.6+/-10.2 vs. 30.3+/-11.4 nmol/l, P < 0.001) but a higher mean erythrocyte folate level (801.8+/-284.6 nmol/l vs. 699.5+/-248.7 nmol/l, P < 0.01) than control subjects. No patient or control subjects had low folate, while only four patients (3.4%) and six control subjects (8.3%) had low erythrocyte folate. Folate levels were not related to patients' age, duration of illness, Hamilton Depression Rating Scale, Beck Depression Inventory and Global Assessment Scale scores, and prior psychotropic drug usage. Both patients and control subjects revealed a high intake of green vegetables. CONCLUSION Patients' lower serum folate level was likely to be secondary to their depression but, being well in the normal range, should not have aggravated their depressive symptoms. Culturally patterned health beliefs and dietary practices can influence the connection between folate status and depression in different societies. LIMITATIONS Patients were not drug-free, while the lack of detailed dietary analysis and longitudinal data on folate level and psychiatric outcome tempered the above conclusion. CLINICAL RELEVANCE Since normofolatemia is normative in Hong Kong, the routine screening of folate levels in Chinese depressive patients is not indicated. However, a double-blind, placebo-controlled trial may be useful for finding out whether Chinese patients will still benefit from folate pharmacotherapy.
Collapse
|
50
|
Perisic O, Fong S, Lynch DE, Bycroft M, Williams RL. Crystal structure of a calcium-phospholipid binding domain from cytosolic phospholipase A2. J Biol Chem 1998; 273:1596-604. [PMID: 9430701 DOI: 10.1074/jbc.273.3.1596] [Citation(s) in RCA: 218] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cytosolic phospholipase A2 (cPLA2) is a calcium-sensitive 85-kDa enzyme that hydrolyzes arachidonic acid-containing membrane phospholipids to initiate the biosynthesis of eicosanoids and platelet-activating factor, potent inflammatory mediators. The calcium-dependent activation of the enzyme is mediated by an N-terminal C2 domain, which is responsible for calcium-dependent translocation of the enzyme to membranes and that enables the intact enzyme to hydrolyze membrane-resident substrates. The 2.4-A x-ray crystal structure of this C2 domain was solved by multiple isomorphous replacement and reveals a beta-sandwich with the same topology as the C2 domain from phosphoinositide-specific phospholipase C delta 1. Two clusters of exposed hydrophobic residues surround two adjacent calcium binding sites. This region, along with an adjoining strip of basic residues, appear to constitute the membrane binding motif. The structure provides a striking insight into the relative importance of hydrophobic and electrostatic components of membrane binding for cPLA2. Although hydrophobic interactions predominate for cPLA2, for other C2 domains such as in "conventional" protein kinase C and synaptotagmins, electrostatic forces prevail.
Collapse
|