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R J Faull

Publications and source records attributed to R J Faull.

29 records · Page 2Linked to original sources
PubMed1993

Affinity modulation of integrin alpha 5 beta 1: regulation of the functional response by soluble fibronectin.

We report that a beta 1 integrin (alpha 5 beta 1) can exist in different affinity states for its soluble ligand, fibronectin. The alpha 5 beta 1 expressed by the erythroleukemic cell line K562 binds soluble fibronectin with low affinity (Kd > 1 microM), but is induced to bind it with 20-fold higher affinity (Kd-54 nM) in the presence of the anti-beta 1 mAb 8A2. This activation seems to be due to direct antibody-induced change in the receptor that does not require intracellular signaling, and is a plausible basis for the 8A2-induced enhancement of beta 1-dependent adhesion to fibronectin and other immobilized ligands (Kovach, N. L., T. M. Carlos, E. Yee, and J. M. Harlan. 1992. J. Cell Biol. 116: 499-509). Fab fragments of 8A2 bind with higher affinity to alpha 5 beta 1 receptor that is occupied by the GRG-DSP peptide ligand suggesting that the antibody functions by stabilizing a high affinity (occupied) conformer of the receptor. A functional consequence of the affinity modulation is that soluble fibronectin (at physiological concentrations) occupies the high affinity receptors, and so becomes an effective inhibitor of adhesion to immobilized fibronectin. In contrast, the majority of low affinity receptors remain unoccupied and are still to mediate cellular adhesion.

Animals↗
PubMed1992

Endothelial cell activation in vasculitis of peripheral nerve and skeletal muscle.

To clarify the role of endothelial cells in the pathogenesis of vasculitis affecting peripheral nerve and skeletal muscle, the endothelial expression of adhesion molecules and major histocompatibility antigens (MHC) in different vasculitic syndromes were studied, and related to the presence of anti-endothelial cell antibodies (AECA). Increased expression of the intercellular adhesion molecule ICAM-1 in vasculitic lesions in nerve and muscle was shown, and this was associated with increased expression of MHC class I and II antigens. AECA were detected in low titre in only a minority of patients. The findings suggest that endothelial cells have a critical role in mediating the tissue injury in vasculitis affecting nerve and muscle and that the process is triggered by cellular and not antibody-mediated mechanism in the majority of patients.

Aged↗
PubMed1989

Tubular expression of intercellular adhesion molecule-1 during renal allograft rejection.

Molecules responsible for adhesion between cells are known to play an important role in the immune response. The expression of one of these molecules, intercellular adhesion molecule-1 (ICAM-1), was examined on normal and allografted kidneys using a specific monoclonal antibody and an indirect immunoperoxidase technique. The expression of this molecule was compared to that of HLA class II antigens. On normal kidneys and most allograft biopsies taken immediately before implantation, ICAM-1 was expressed only on vascular endothelial cells (VEC) and parietal epithelium of Bowman's capsule. In the 11 kidneys where biopsies were available before and after transplantation, the appearance of rejection was associated with de novo expression of ICAM-1 on renal tubular epithelial cells that closely paralleled that of HLA class II antigens. In addition, an increase in endothelial cell expression of these molecules was also seen in rejection. In 23 random allograft biopsies, most of those with rejection showed tubular expression of both HLA class II antigens and ICAM-1. However, the presence of these molecules on tubules in several biopsies that did not show rejection limits the clinical usefulness of monitoring these antigens in posttransplant biopsies. The upregulation of these molecules is presumed to be secondary to the release of cytokines by cells infiltrating the allograft, although other mechanisms may be operating that explain the expression of these molecules in nonrejecting grafts.

Antigens, Surface↗
PubMed1987

Adult Henoch-Schönlein nephritis.

A retrospective study was performed of all patients at the Royal Adelaide Hospital over a ten-year period with biopsy proven Henoch-Schönlein nephritis. The records of 27 patients were examined, with emphasis on clinical and histopathological presentation, treatment and outcome. A scheme for assessing glomerular histology is presented, and severity correlated with prognosis of the disease. At presentation unfavourable prognostic indicators were acute renal impairment, crescents in greater than 20% of glomeruli, and severe glomerular histological lesions. Four patients died as a result of the disease, and 20 of the patients had evidence of continued renal abnormality at follow-up. Adult Henoch-Schönlein nephritis is a potentially catastrophic disease, and requires careful assessment at presentation.

Biopsy↗
PubMedDate not supplied

Expression of defensin antimicrobial peptides in the peritoneal cavity of patients on peritoneal dialysis.

OBJECTIVE: To investigate the expression and regulation of defensins in the peritoneal cavity of peritoneal dialysis (PD) patients. DESIGN: The presence of defensins in the peritoneal cavity was assessed using reverse transcription polymerase chain reaction (RT-PCR). In vivo defensin expression was analyzed in human peritoneal membrane biopsies and in peritoneal cavity leukocytes isolated from spent dialysate. Defensin expression in vitro was assessed in cultured human peritoneal mesothelial cells (HPMC) and confirmed with PCR Southern blot and DNA sequencing. The effect of tumor necrosis factor alpha (TNFalpha) and epidermal growth factor (EGF) on beta2 defensin expression in HPMC was analyzed by Northern blot analysis and RT-PCR respectively. RESULTS: Both alpha and beta classes of defensins are expressed in the peritoneal cavity of PD patients. Messenger RNA for the alpha-defensin human neutrophil peptide 3 and for beta-defensin-1 (hbetaD-1) were found in preparations containing predominantly peritoneal leukocytes, whereas beta-defensin-2 (hbetaD-2) is expressed by HPMC. HPMC isolated from different individuals displayed variability in both basal hbetaD-2 expression and in response to stimulation by TNFalpha. Conversely, EGF consistently downregulated the level of hbetaD-2 message in HPMC. CONCLUSION: Alpha- and beta-defensins are expressed in the peritoneal cavity, and hbetaD-2 is the main defensin present in the peritoneal membrane. Variable levels of expression of hbetaD-2 by mesothelial cells were seen, with evidence of regulation by cytokines and growth factors. This provides evidence for a previously unknown mechanism of innate immunity at that site.

Base Sequence↗