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254 results on '"Chua, K. Y."'

39. Expression of the leukocyte common antigen CD45 by endothelium

Author

Kevin Forsyth, Chua, K. Y., Talbot, V., and Thomas, W. R.

Subjects
Immunology, Immunology and Allergy
Abstract

The CD45 family of Ag expressed by leukocytes play a key role in lymphocyte activation. In this study, we identify both a restricted pattern of expression of CD45 Ag by human endothelial cells and differences in m.w. of endothelial CD45 compared with lymphocyte CD45. Initially, immunoperoxidase staining of endothelial cells in culture revealed the presence of the CD45RO isoform provided the endothelial cells had been stimulated by IL-1 for several days. No other isoform of CD45 was detected by immunoperoxidase staining of endothelium. Leukocyte common antibodies, reputed to detect all isoforms of CD45, did not detect endothelial CD45RO. A polymerase chain reaction method was then used to demonstrate that the message for the CD45RO isoform was constitutively present, with increased levels after IL-1 stimulation. Western blot confirmed the presence of the RO isoform. No other CD45 isoform was detected, either by PCR amplification for message or by Western blot. There were clear differences between lymphocyte and endothelial CD45. The RO isoform expressed by endothelium has an estimated M(r) of 235,000 in contrast to lymphocyte RO that, on our gels, has an estimated M(r) of 190,000. Given the large surface area of endothelium (approximately 1 km2 in the human), the close apposition of lymphocytes and endothelium in immunologic tissues such as lymph nodes, and the pivotal role CD45 plays in activation, expression of CD45RO by endothelium may have important implications in lymphocyte-endothelial interactions. This is most likely to occur in endothelium after a few days of IL-1 stimulation, e.g., at sites of chronic inflammation, or in the draining lymph node of an inflammatory focus.

Published
1993
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44. Clinical utility of panfungal polymerase chain reaction for the diagnosis of invasive fungal disease: a single center experience.

Author

Trubiano, J. A., Dennison, A. M., Morrissey, C. O., Chua, K. Y., Halliday, C. L., Chen, S. C.-A., and Spelman, D.

Abstract

The role of panfungal polymerase chain reaction (PCR) assays for diagnosis of invasive fungal disease (IFD) is inadequately defined. We describe the use of an internal transcribed spacer 1 (ITS-1) region-directed panfungal PCR in this context at a tertiary referral transplant center. A retrospective review of patients at Alfred Health, Melbourne, Australia (2009-2014) who had clinical samples referred for panfungal PCR testing was conducted. Baseline patient characteristics, antifungal drug history, fungal culture/histopathology, and radiology results were recorded. For bronchoalveolar lavage (BAL) fluid samples, identification of a fungus other than a Candida spp. was defined as a potential pathogen. Of 138 panfungal PCR tests (108 patients), 41 (30%) were positive for a fungal product. Ninety-seven percent (134/138) of specimens were from immunocompromised hosts. Thirteen percent (19/138) of panfungal PCR positive results were for potential pathogens and potential pathogens were detected more frequently in tissue as compared with BAL (12/13 vs. 6/26; P = .0001). No positive panfungal PCR results were obtained from CSF specimens. If histopathology examination was negative, panfungal PCR identified a potential pathogen in only 12% (11/94) of specimens. For the 20 culture negative/ histopathology positive specimens, diagnosis of IFD to causative species level by panfungal PCR occurred in 35% (6/20). Sterile site specimens, in particular tissue, were more frequently panfungal PCR positive for potential pathogens than BAL. The utility of panfungal PCR appears greatest in tissue specimens, as an adjunct to histopathology to improve diagnostic sensitivity and specificity. Based on the results of this study we are now only testing tissue specimens by panfungal PCR. [ABSTRACT FROM AUTHOR]

Published
2016
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49. IgE binding studies with large peptides expressed from Der p II cDNA constructs

Author

Chua, K-Y, Greene, W.K., Kehal, P., Thomas, W.R., Chua, K-Y, Greene, W.K., Kehal, P., and Thomas, W.R.

Abstract

The major mite allergen Der p II shows marked resistance to denaturation and is expressed from cDNA in bacteria with almost all of its IgE binding activity. Despite these properties, the IgE binding activity appears to be dependent on maintaining the complete primary structure. Random fragment libraries of cDN A, able to code for up to 93 of the 129 amino acid residue protein, did not express IgE binding peptides. Large overlapping peptides 1–69, 69–129 and 42–117 expressed as the fusions from the glutathione transferase of pGEX vectors only had binding activity with IgE in 15 out of 57 sera, and this was typically weak. Sera from children with atopic dermatitis bound IgE in seven out of eight cases but this was also weak compared with their strong reactivity to intact recombinant Der p II. The inability of such large peptides to form IgE binding structures suggests that the antigenic determinants of Der p II are highly conformational and restricted.

Published
1991

50. Allergy to the house dust mite

Author

Thomas, W., Chua, K-Y, Greene, W.K., Thomas, W., Chua, K-Y, and Greene, W.K.

Abstract

Although the house dust mite has been recognised as the most important indoor allergen for over 25 years the development of effective therapeutic strategies against dust mite allergies has been hampered by the difficulties involved in characterising the antigens produced by the organism. Until recently, the only materials available for clinical investigation were crude extracts of dried mites. With the advent of molecular cloning however, scientists have begun the process of accurately characterising each of the allergens produced by the dust mite. The ultimate aim is to learn enough to be able to produce specific therapeutic agents for some of the major allergic disorders like asthma, which are caused by these allergens.

Published
1990

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