Search PubMed⌕ Search

Biomedical subjects

J Thomson

Publications and source records attributed to J Thomson.

At least 37 records · Page 2Linked to original sources
PubMed2000

A rapid and sensitive reporter gene that uses green fluorescent protein expression to detect chemicals with estrogenic activity.

A reporter gene sequence was constructed within a eukaryotic expression vector. The altered plasmid contained 2 sequential estrogen response elements (ERE) coupled to a human phosphoglycerate kinase (PGK) promoter inserted upstream from a cDNA sequence encoding enhanced green fluorescent protein (GFP) with a 3'-polyadenylation signal. The plasmid was linearized and transfected into MCF-7 cells, a human breast cancer-derived line that expresses the estrogen receptor (ER). No selectable marker was present in the plasmid, requiring stably transfected cells to be selected by fluorescence-activated cell sorting based on GFP expression after the cells were treated with 10(-9) M 17beta-estradiol (E2). Stably transfected MCF-7 cells (MCF7-ERE) exhibited 2000-3000 times more fluorescence at 488 nm excitation and 512 nm emission than non-transfected cells. MCF7-ERE cells exhibited a linear increase in GFP expression induced over a range of 10(-12) M E2, a concentration giving 2 times the background expression, to maximal expression at 3 x 0(-10) M E2. From the maximal level, GFP expression plateaued, and then declined when E2 was increased to the highest concentration tested, 10(-7) M. 4-Hydroxytamoxifen (TFN-OH) treatment of cells produced a dose-dependent inhibition of E2-induced GFP expression, indicating the interaction of ER in the regulation of GFP gene expression. A series of estrogenic chemicals were evaluated for their capacity to induce GFP expression in MCF7-ERE cells, showing induced expression of GFP at concentrations 2-4 log units higher than the E2 concentration giving maximal GFP expression. The ERE-PGK-GFP reporter gene system is capable of rapid GFP expression in the presence of low concentrations of E2, and of quantifying estrogenicity of chemicals compared with a standard curve of the natural ligand, 17beta-estradiol.

Cell Division↗
PubMed2000

Orf virus encodes a novel secreted protein inhibitor of granulocyte-macrophage colony-stimulating factor and interleukin-2.

The parapoxvirus orf virus encodes a novel soluble protein inhibitor of ovine granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2). The GM-CSF- and IL-2-inhibitory factor (GIF) gene was expressed as an intermediate-late viral gene in orf virus-infected cells. GIF formed homodimers and tetramers in solution, and it bound ovine GM-CSF with a K(d) of 369 pM and ovine IL-2 with a K(d) of 1.04 nM. GIF did not bind human GM-CSF or IL-2 in spite of the fact that orf virus is a human pathogen. GIF was detected in afferent lymph plasma draining the skin site of orf virus reinfection and was associated with reduced levels of lymph GM-CSF. GIF expression by orf virus indicates that GM-CSF and IL-2 are important in host antiviral immunity.

Amino Acid Sequence↗
PubMed2000

Annual report of the National Influenza Surveillance Scheme, 1999.

An effective national surveillance system is an essential component of a program for the control of influenza. The National Influenza Surveillance Scheme includes data from sentinel general practice consultations for influenza-like illness, laboratory reports of influenza and absenteeism rates from a national employer. The 1999 season peaked between May and September with maximal activity between July and August. Influenza A was the dominant type in all States and Territories with influenza A H3N2 viruses predominating and influenza A H1N1 occurring sporadically. There was no evidence of significant drift among the H3N2 isolates (A/Sydney-like strains) whereas the H1N1 isolates showed significant antigenic changes from the vaccine strain A/Beijing/262/95 and were closely related to a new variant A/New Caledonia/20/99. A small peak in influenza B activity occurred towards the end of the influenza season and isolates remained closely related to the vaccine reference strain B/Beijing/184/93.

Antigens, Viral↗
PubMed2000

Cells expressing dendritic cell markers are present in the rheumatoid nodule.

OBJECTIVE: To determine if dendritic antigen-presenting cells (DC) are present in rheumatoid nodules, as has been reported in the synovial lesions of rheumatoid arthritis. METHODS: Nodules (n = 14) were examined with monoclonal antibodies (Mab) recognizing the DC differentiation/activation markers CD83, CMRF44, and CMRF56 and an antibody recognizing the CD1a antigen present on epithelial tissue associated DC. Results. Cells expressing CMRF44 were common in rheumatoid nodules, comprising 22% of nucleated cells versus 13% in synovial membranes (n = 10). Cells positive for CD1a (5%) and CD83 (2%) were less common. A majority (86%) of CMRF44 positive cells were also positive for the macrophage marker CD14. This left a significant minority of putative DC that were single stained with CMRF44. CONCLUSION: Cells bearing DC markers are as frequent in the rheumatoid nodule as in the synovial lesions. A majority are "indeterminate" cells that are CD14 positive but a proportion are single stained putative DC. The lack of lymphoid collections containing DC and T and B lymphocytes in the nodule suggests that local presentation of antigen may not occur in the rheumatoid nodule, as is thought to be the case in synovial membranes containing lymphoid follicles. This difference could potentially be explained by different states of activation, and differentiation of DC within the 2 lesions.

Adult↗
PubMed1999

Australia's notifiable diseases status, 1998. Annual report of the National Notifiable Diseases Surveillance System.

In 1998 there were 85,096 notifications to the National Notifiable Diseases Surveillance System; slightly lower than in 1997 (89,579). The number of measles cases remained low, and well below the number reported in the outbreak years of 1993 and 1994. Rubella notifications further decreased and remained low in 1998. The Measles Control Campaign from August to November 1998, did not impact significantly on the number of measles or rubella cases reported for 1998. Notifications of Haemophilus influenzae type b reached a record low since surveillance began in 1991, and appeared to have stabilised at a low rate since the introduction of the conjugated vaccine in 1992. The previously reported outbreak of pertussis in 1997 tapered off in early 1998. Food-borne disease, or detection of disease, appeared to be on the rise with an increase in notification rates of campylobacteriosis and salmonellosis. Notifications of hepatitis A decreased, correcting the previous high number of notifications in 1997. Sexually transmissible diseases (STDs) increased. Notifications for chlamydial infection were the highest for all sexually transmitted diseases and third highest for all notifiable diseases. Notifications of gonococcal infection also continued to rise and have doubled since 1991, whilst notifications for syphilis increased slightly after falling steadily over recent years. Arbovirus infections of concern in 1998 were dengue outbreaks in Far North Queensland and the first case of Japanese Encephalitis for mainland Australia, highlighting the importance of surveillance of arboviruses and vectors for their detection and management.

Australia↗
PubMed1999

The cloning and expression of the cDNA for ovine stem cell factor (kit-ligand) and characterization of its in vitro haematopoietic activity.

The cDNA encoding the soluble form of ovine stem cell factor (SCF) has been cloned and expressed. The soluble protein is predicted to be 165/166 amino acids in length, one more than the human and murine SCFs with which it shares 87% and 81% identity respectively. Ovine SCF has 98.5%, 95% and 91% identity with cattle, pig and dog SCF, respectively. The recombinant ovine (rov) SCF protein has been expressed in Chinese hamster ovary (CHO) cells, purified, and its biological activity on ovine bone marrow cells compared with that of interleukin 3 (rovIL-3), granulocyte-macrophage colony-stimulating factor (rovGM-CSF), interleukin 5 (rovIL-5), human macrophage colony-stimulating factor (M-CSF) and human erythropoietin (epo). On its own rovSCF supported the development of small numbers of neutrophil, macrophage, eosinophil, granulocyte-macrophage, mixed cell phenotype, haemopoietic blast cell and basophilic granular cell colonies in a soft agar clonogenic assay. In combination with each of the above cytokines rovSCF supported an increase in the number and size of the lineage-specific colony types that were stimulated by the other cytokines on their own. In an assay for precursors of multipotential colony-forming cells (multi-CFC), rovSCF in combination with rovIL-3 (but neither cytokine alone) supported the development of these early haematopoietic progenitor cells.

Amino Acid Sequence↗
PubMed1999

Immunisation initiatives in general practice. Important lessons from division projects.

AIM: To examine immunisation projects undertaken by divisions of general practice through the Divisions and Project Grants Program in the period from 1993 to mid 1997. METHOD: A simple descriptive frequency analysis was conducted of information from the National Information Service Divisions Project database and evaluation reports of the project characteristics and methodology such as: year commenced; duration; location; funding; target groups; intervention; needs assessment; aim(s); study design; measurement (assessment) and outcome(s). RESULTS: Forty-four funded immunisation projects were identified and of these, 12 projects with completed evaluation reports were analysed. Most projects were of 12-14 months duration, and were funded for a mean of $56,349 and median of $46,348 for the 44 funded projects and a mean $44,348 and median $40,318 for the 12 with evaluation reports. Most projects included a needs assessment. The main target groups were general practitioners, the general community, and children. Of the wide spectrum of interventions used, education and/or promotion and register and/or reminder systems were the most common. Study designs, the quality of measurement and outcomes were variable. CONCLUSION: In the future with the move to outcome based block funding, it will be important for projects to adopt broader target groups, refine and develop interventions and develop greater sustainability through responding to local needs, improving design and evaluation and ongoing funding.

Australia↗
PubMed1998

A thermodynamic study of the binding of linear and cyclic oligosaccharides to the maltodextrin-binding protein of Escherichia coli.

Isothermal titration calorimetric (ITC) studies over a range of temperatures of the binding of maltose, maltotriose, maltotetraose and beta-cyclodextrin to the maltodextrin-binding protein (MBP) of Escherichia coli are reported. The binding constants of maltose, maltotriose and beta-cyclodextrin are not very different, namely 8.7 x 10(5), 13.0 x 10(5) and 2.55 x 10(5) M-1, respectively at 25 degrees C. The calorimetric data obtained with maltotetraose cannot be interpreted in terms of a definite binding constant. The binding of maltose and maltotriose is endothermic with a large entropy increase while that of beta-cyclodextrin is exothermic, with a smaller entropy increase. The binding of maltotetraose was endothermic or exothermic depending on the temperature.

Bacterial Proteins↗
PubMed1998

The orf virus OV20.0L gene product is involved in interferon resistance and inhibits an interferon-inducible, double-stranded RNA-dependent kinase.

The parapoxvirus orf virus was resistant to type 1 (IFN-alpha) and type 2 (IFN-gamma) interferons in cultures of ovine cells. The recently identified orf virus OV20.0L gene exhibits 31% predicted amino acid identity to the vaccinia virus E3L interferon-resistance gene, and is referred to as the (putative) orf virus interferon-resistance gene (OVIFNR). The objective of this study was to determine whether OVIFNR was involved in interferon resistance. Recombinant OVIFNR as a thioredoxin fusion protein (OVIFNR-Tx) inhibited the activation (by autophosphorylation) of an interferon-inducible, double-stranded (ds) RNA-dependent kinase (PKR) of sheep, which was shown to bind dsRNA (poly I:C). PKR in other species is involved in the inhibition of protein synthesis as part of the antiviral state in infected cells. Virus-infected cell lysates, but not control lysates, from cells grown in the presence of cytosine arabinoside also contained PKR inhibitory activity, which indicated that the inhibitory activity was associated with early viral gene expression. Significantly, the OVIFNR gene expressed in interferon-treated ovine fibroblasts protected the unrelated Semliki Forest virus from the antiviral effect of both type 1 and type 2 interferons. Taken together, the results indicate that the OVIFNR gene functions as an interferon-resistance gene, the product of which inhibits PKR in a similar way to the vaccinia virus E3L gene product.

Animals↗
PubMed1998

Determinants of disease in the simian immunodeficiency virus-infected rhesus macaque: characterizing animals with low antibody responses and rapid progression.

Clinical and laboratory markers of simian immunodeficiency virus (SIV) infection were studied during the first 3 months after intravenous inoculation of rhesus macaques. Virus-binding serum antibody titres were correlated strongly with disease progression (P < 0.005) and were predictive of disease outcome by 7 weeks after inoculation. Low virus-binding serum antibody responses to SIV occurred in animals that also showed acute depletion of circulating CD20+ B cells. Acute damage to the CD4+ T cell and CD20+ B cell populations rendered some animals incapable of mounting virus-specific antibody responses and these macaques became the rapidly progressing cases comprising approximately 20-30% of infected animal cohorts.

Animals↗