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A J Rees

Publications and source records attributed to A J Rees.

At least 19 recordsLinked to original sources
PubMed2006

A glass foreign body in the knee joint mistaken for ACL avulsion: an unusual case.

Foreign body in the knee is associated with trauma to knee or deliberate self harm. We see them often in clinical practice. They come in all forms and shapes. Very rarely one can find a foreign body within a joint without obvious external scarring (e.g. needle). We have not come across anywhere in the literature of a large foreign body in the knee joint without a definitive history of injury where the external scar has healed so well to become inconspicuous. With this background it is even more difficult when the X-rays mimic anterior cruciate ligament (ACL) avulsion. This case report highlights the fact that diagnosis of a foreign body in the knee joint can sometimes be challenging and almost impossible when there is no history of any injury and when the X-ray mimics ACL avulsion.

Adult↗
PubMed2002

Antigen presentation by macrophages is enhanced by the uptake of necrotic, but not apoptotic, cells.

The aim of this study was to determine whether phagocytosis of necrotic or apoptotic cells affects antigen presentation by murine bone marrow-derived macrophages. After uptake of necrotic neutrophils, macrophages were able to stimulate significantly higher T cell proliferation in vitro against both the recall antigen albumin and the mitogen concanavalin A. No such effect was seen following phagocytosis of apoptotic neutrophils. Flow cytometry revealed that, within 4h of ingestion, macrophages that had taken up the necrotic cells expressed higher levels of CD40 than those that had phagocytosed apoptotic cells. Macrophage cultures pulsed with apoptotic, but not necrotic, neutrophils contained higher levels of transforming growth factor beta1, but lower concentrations of tumour necrosis factor alpha, compared to untreated controls. Our interpretation of these results is that macrophages that have taken up necrotic neutrophils co-stimulate T cells with greater efficiency due to rapid CD40 up-regulation, whereas those that have ingested apoptotic cells are not only ineffective in co-stimulation, but also secrete inhibitory cytokine.

Animals↗
PubMed2001

Long-term outcome of anti-glomerular basement membrane antibody disease treated with plasma exchange and immunosuppression.

BACKGROUND: Anti-glomerular basement membrane (GBM) antibody disease is an autoantibody-mediated disorder that usually presents as rapidly progressive glomerulonephritis, often with pulmonary hemorrhage (the Goodpasture syndrome). It is reported that patients with severe renal failure do not generally recover renal function. OBJECTIVE: To examine the long-term outcome of severe anti-GBM antibody disease. DESIGN: Retrospective review of patients treated for confirmed anti-GBM antibody disease over 25 years. SETTING: A tertiary referral center in the United Kingdom. PATIENTS: 71 treated patients with anti-GBM antibody disease. INTERVENTION: All patients received plasma exchange, prednisolone, and cyclophosphamide. MEASUREMENTS: Patient and renal survival, renal histology, and antibody levels. RESULTS: Patients who presented with a creatinine concentration less than 500 micromol/L (5.7 mg/dL) (n = 19) had 100% patient survival and 95% renal survival at 1 year and 84% patient survival and 74% renal survival at last follow-up. In patients who presented with a creatinine concentration of 500 micromol/L or more (>/=5.7 mg/dL) (n = 13) but did not require immediate dialysis, patient and renal survival were 83% and 82% at 1 year and 62% and 69% at last follow-up. In patients who presented with dialysis-dependent renal failure (n = 39), patient and renal survival were 65% and 8% at 1 year and 36% and 5% at last follow-up. All patients who required immediate dialysis and had 100% crescents on renal biopsy remained dialysis dependent. CONCLUSIONS: Patients with the Goodpasture syndrome and severe renal failure should be considered for urgent immunosuppression therapy, including plasma exchange, to maximize the chance of renal recovery. Patients needing immediate dialysis are less likely to recover.

Adolescent↗
PubMed2001

Combinatorial model of chemokine involvement in glomerular monocyte recruitment: role of CXC chemokine receptor 2 in infiltration during nephrotoxic nephritis.

A sequential model involving chemokines has been proposed for leukocyte extravasation into areas of inflammation; however, site-specific aspects remain to be elucidated. Hence, we studied the role of chemokines produced by mesangial (MC) or glomerular endothelial cells (GEC) and their receptors in glomerular recruitment of monocytes. Stimulation of MC with TNF-alpha up-regulated mRNA and protein of CC and CXC chemokines but not constitutive expression of the CX(3)C chemokine fractalkine. While growth-related activity (GRO)-alpha was immobilized to MC proteoglycans, monocyte chemotactic protein (MCP)-1 was secreted into the soluble phase. Firm adhesion and sequestration of monocytes on activated MC was supported by the GRO-alpha receptor CXCR2 and to a lesser extent by CX(3)CR, whereas the MCP-1 receptor CCR2 contributed to their transendothelial chemotaxis toward activated MC. In contrast, fractalkine mRNA and protein was induced by TNF-alpha in transformed rat GEC, and both CXCR2 and CX(3)CR mediated monocyte arrest on GEC in shear flow. The relevance of these mechanisms was confirmed in a rat nephrotoxic nephritis model where acute glomerular macrophage recruitment was profoundly inhibited by blocking CXCR2 or CCR2. In conclusion, our results epitomize a combinatorial model in which chemokines play specialized roles in driving glomerular monocyte recruitment and emphasize an important role for CXCR2 in macrophage infiltration during early phases of nephrotoxic nephritis.

Animals↗
PubMed2001

Macrophages transfected with adenovirus to express IL-4 reduce inflammation in experimental glomerulonephritis.

Nephrotoxic nephritis (NTN) is characterized by acute macrophage-dependent inflammation and serves as a model of human glomerulonephritis. In this study we have transfected rat macrophages with recombinant adenovirus expressing IL-4 (Ad-IL4) and demonstrated that these transfected macrophages develop fixed properties as a result of transfection, as shown by reduced NO production in response to IFN-gamma and TNF. Ad-IL4-transfected macrophages localized with enhanced efficiency to inflamed glomeruli after renal artery injection in rats with NTN compared with adenovirus expressing beta-galactosidase (Ad-beta gal)-transfected macrophages and produced elevated levels of the cytokine in glomeruli in vivo for up to 4 days. The delivery of IL-4-expressing macrophages produced a marked reduction in the severity of albuminuria (day 2 albuminuria, 61 +/- 15 mg/24 h) compared with unmodified NTN (day 2 albuminuria, 286 +/- 40 mg/24 h; p < 0.01), and this was matched by a reduction in the number of ED1-positive macrophages infiltrating the glomeruli. Interestingly, the injection of IL-4-expressing macrophages into single kidney produced a marked reduction in the numbers of ED1-positive macrophages in the contralateral noninjected kidney, an effect that could not be mimicked by systemic delivery of IL-4-expressing macrophages. This implies that the presence of IL-4-expressing macrophages in a single kidney can alter the systemic development of the inflammatory response. Macrophage transfection and delivery provide a valuable system to study and modulate inflammatory disease and highlight the feasibility of macrophage-based gene therapy.

Adenoviridae↗
PubMed2001

Macrophages in renal inflammation.

This review describes recent advances in macrophage biology in the context of renal inflammation. It highlights the importance of the activated macrophage for the progression and resolution of renal disease, and discusses recent and potential future approaches to modify macrophage function selectively within the kidney to activate them specifically to promote the healing of kidney disease.

Humans↗
PubMed2000

Activated macrophages direct apoptosis and suppress mitosis of mesangial cells.

During inflammation in the glomerulus, the complement of resident myofibroblast-like mesangial cells is regulated by mitosis and apoptosis, but the cellular mechanisms controlling the size of mesangial cell populations have remained obscure. Prompted by studies of development, we sought evidence that macrophages regulate mesangial cell number. Rat bone marrow-derived macrophages primed with IFN-gamma then further activated in coculture with LPS or TNF-alpha elicited a 10-fold induction of rat mesangial cell apoptosis and complete suppression of mitosis, effects inhibitable by the NO synthase inhibitors L-monomethyl arginine and L-N(6)-(1-iminoethyl) lysine dihydrochloride. Complete dependence upon macrophage-derived NO was observed in comparable experiments employing activated bone marrow macrophages from wild-type and NO synthase 2(-/-) mice. Nevertheless, when mesangial cells were primed with IFN-gamma plus TNF-alpha, increased induction by activated macrophages of mesangial apoptosis exhibited a NO-independent element. The use of gld/gld macrophages excluded a role for Fas ligand in this residual kill, despite increased expression of Fas and increased susceptibility to soluble Fas ligand exhibited by cytokine-primed mesangial cells. Finally, activated macrophages isolated from the glomeruli of rats with nephrotoxic nephritis also induced apoptosis and suppressed mitosis in mesangial cells by an L-monomethyl arginine-inhibitable mechanism. These data demonstrate that activated macrophages, via the release of NO and other mediators, regulate mesangial cell populations in vitro and may therefore control the mesangial cell complement at inflamed sites.

Animals↗
PubMed2000

Macrophages from inflamed but not normal glomeruli are unresponsive to anti-inflammatory cytokines.

This study examined the properties and responsiveness to cytokines of macrophages purified from normal and nephritic glomeruli to ascertain whether macrophages activated in vivo develop programmed unresponsiveness to cytokines as do bone marrow-derived macrophages in vitro when activated by interferon-gamma (IFN-gamma), tumor necrosis factor (TNF), interleukin-4 (IL-4), or transforming growth factor-beta (TGF-beta). Macrophages from normal glomeruli did not generate nitric oxide (NO) spontaneously but only after treatment with IFN-gamma and TNF-alpha. NO generation by these macrophages was abrogated by administering IL-4, TGF-beta, or TNF-alpha before but not after IFN-gamma treatment. Glomerular macrophages also expressed beta-glucuronidase, which was increased by TGF-beta and decreased by IFN-gamma and TNF. By contrast, glomerular macrophages from rats with nephrotoxic nephritis did not express beta-glucuronidase even after exposure to TGF-beta. Furthermore, they generated NO spontaneously, and this spontaneous generation of NO was not suppressed by IL-4, TGF-beta, or TNF-alpha. Systemic treatment of nephritic rats with IL-4 reduced NO generation by 40% but did not prevent activation, which is similar to the effect of IL-4 on bone marrow-derived macrophages in vitro when given simultaneously with IFN-gamma. We conclude that macrophages infiltrating inflamed glomeruli have developed programmed unresponsiveness to activating cytokines. This may enable them to function appropriately in the complex conditions within an inflammatory focus.

Animals↗
PubMed2000

Gene transfer into inflamed glomeruli using macrophages transfected with adenovirus.

In vivo gene transfer to sites of inflammatory disease provides a novel method both for studying the effects of cytokines and growth factors, and for therapeutic intervention. Macrophages play a pivotal role in the development and control of inflammation and are therefore logical cells to use for genetic modification and in vivo gene delivery. In this study we show that macrophages (both cell lines and primary cultures) can be transfected by recombinant adenoviruses expressing beta-galactosidase, that the macrophages become activated by the transfection process as determined by generation of nitric oxide and can be easily manipulated to localise to inflamed glomeruli after direct injection into the renal artery of rats with an experimentally induced glomerular inflammation caused by nephrotoxic nephritis. The injection of transfected macrophages reduces the severity of injury in this model of glomerulonephritis as shown by a reduction in the degree of albuminuria. This approach provides a favourable system for gene delivery in inflammatory disease and shows that both the functional properties of the transfected macrophage as well the transgene it is engineered to produce are relevant for in vivo gene transfer. Gene Therapy (2000) 7, 263-270.

Adenoviridae↗
PubMed2000

Transforming growth factor-beta isoforms and glomerular injury in nephrotoxic nephritis.

BACKGROUND: Transforming growth factor-beta has three main isoforms (TGF-beta1, TGF-beta2, and TGF-beta3) that have distinct but overlapping functions in immunity, inflammation, and tissue repair. TGF-beta1 has been implicated in progressive renal scarring, but the roles of TGF-beta2 and TGF-beta3 are less clear. The purpose of this study was to characterize the expression of all three isoforms in nephrotoxic nephritis (NTN) in rats and to determine the effect of TGF-beta3 infusions on injury because of its reported combined anti-inflammatory and antifibrotic effects. METHODS: TGF-beta1, TGF-beta2, and TGF-beta3 expression was analyzed by immunohistochemistry and RNase protection assays. TGF-beta3 was administered by osmotic minipumps at 2 microg/day, a dose shown to alter glomerular macrophage function in vivo. Injury was assessed morphologically and functionally. RESULTS: The three TGF-beta isoforms showed a different distribution in normal rats and after the induction of nephritis. TGF-beta1 was only detected in glomeruli of the most severely nephritic rats. TGF-beta2 was found in glomerular neutrophils, whereas damaged podocytes expressed TGF-beta3. Infusions of TGF-beta3 did not reduce proteinuria over seven days after the induction of nephritis. They did, however, have a profound effect on glomerular macrophage number (7.76 +/- 4.1 in treated rats vs. 14.4 +/- 4.7 in controls, P < 0.02). The numbers of class II-positive macrophages were similar in the two groups, whereas class II-negative macrophages infiltrating glomeruli were significantly decreased (4.06 +/- 3.1 vs. 9.1 +/- 4.4, P < 0.02). TGF-beta did not influence the amount of glomerular matrix. CONCLUSIONS: TGF-beta isoforms have different expressions and presumptively different roles in NTN. The infusion of pharmacological doses of TGF-beta3 has profound effects on macrophages infiltrating nephritic glomeruli and reveals marked heterogeneity of infiltrating macrophages.

Animals↗
PubMed2000

Properties of HLA class II molecules divergently associated with Goodpasture's disease.

Goodpasture's disease provides an opportunity to analyse molecular mechanisms that may underlie MHC class II associations with autoimmune disease because it is caused by autoimmunity to a defined antigen [the 230 amino acid NC1 domain of the alpha3 chain of type IV collagen (alpha3(IV)NC1)] and has strong HLA class II associations. We compared the alpha3(IV)NC1 peptide binding of class II molecules with strong positive (DR15) and dominant negative (DR7/1) associations using an inhibition binding assay and short synthetic peptides spanning the sequence of alpha3(IV)NC1. DR15 in general bound the peptides with low affinity (three of 23 < 100 nM) compared to DR1 and DR7 (12 and 10 < 100 nM respectively), and no peptide bound DR15 with much higher affinity (>10-fold) than both DR1 and DR7. Thus DR15 molecules are unlikely to increase susceptibility to Goodpasture's disease by presenting a particular alpha3(IV)NC1-derived peptide uniquely well and DR1/7 are unlikely to protect by their inability to present particular peptides. However DR1/7 could protect by capturing alpha3(IV)NC1 peptides and preventing their display bound to DR15; the binding data suggest that all the major (biochemically detectable) alpha3(IV)NC1 peptides presented bound to DR15 by DR15 homozygous antigen-presenting cells (APC) would bind preferentially to DR1/7 in DR15, 1/7 heterozygote APC.

Alleles↗
PubMed1999

Previous uptake of apoptotic neutrophils or ligation of integrin receptors downmodulates the ability of macrophages to ingest apoptotic neutrophils.

Clearance of apoptotic neutrophils (polymorphonuclear leukocyte [PMN]) by macrophages is thought to play a crucial role in resolution of acute inflammation. There is increasing evidence that ingestion of apoptotic cells modulates macrophage behavior. We therefore performed experiments to determine whether ingestion of apoptotic PMN modulated the uptake process itself. Rat bone marrow-derived macrophages (BMDM) ingested apoptotic PMN by a process that was enhanced by tumor necrosis factor (TNF) and attenuated by interferon (IFN)-gamma, interleukin (IL)-4, and IL-10. It was inhibitable by the tetrapeptide arg-gly-gln-ser (RGDS), therefore implicating the alphavbeta3/CD36/thrombospondin pathway. Interaction of apoptotic PMN with BMDM for 30 minutes, 48 hours before rechallenge reduced uptake of apoptotic PMN by 50% compared with previously unchallenged BMDM. Blocking initial uptake with RGDS abrogated the effect of preexposure. Comparable and sustained attenuation of uptake was obtained by ligating alphavbeta3 with the monoclonal antibody (MoAb), F11, after a delay of more than 90 minutes, whereas MoAbs to CD25 and CD45 had no effect. Ligation of alpha6beta1 and alpha1beta2, integrins not previously implicated in the engulfment of apoptotic cells also decreased uptake with similar kinetics to F11. Therefore, apoptotic PMN regulate their own uptake through an integrin-dependent process, which can be reproduced by ligation of other integrins expressed by macrophages.

Animals↗
PubMed1999

The HLA complex in Goodpasture's disease: a model for analyzing susceptibility to autoimmunity.

Human lymphocyte antigen (HLA) associations are recognized for many autoimmune diseases, but the mechanisms are not clear. Goodpasture's disease provides a unique opportunity to investigate possible mechanisms because strong HLA associations are known, the autoantigen is well defined, and major antigen-derived peptides presented bound to HLA molecules have been identified. Therefore, it may be possible to directly analyze interactions between the antigen and HLA molecules associated with the disease, and to examine influences on antigen presentation to T cells. Towards this goal, we present a detailed analysis of HLA associations with the disease and examine molecular mechanisms that could account for them.

Alleles↗
PubMed1999

Macrophage activation and programming and its role for macrophage function in glomerular inflammation.

Macrophages have a central role in the control of inflammation because, depending on the local microenvironment, they can develop into cells that cause further injury or facilitate tissue repair. Understanding what signals determine whether macrophages develop into cells that promote injury or facilitate repair is one of the most important issues in inflammatory cell biology, not least because of the opportunities for developing novel therapies. This is highly relevant to glomerulonephritis because of the prominence of the macrophage infiltrate in all types of severe or progressive nephritis, and the present unsatisfactory nature of treatments for these diseases. This review will focuses on how macrophages are activated in vitro and in normal and inflamed glomeruli. The new concept of 'macrophage programming' is introduced and novel strategies to alter macrophage function within nephritic glomeruli that could be used for the treatment of glomerular inflammation are highlighted.

Animals↗
PubMed1999

Differential effects of necrotic or apoptotic cell uptake on antigen presentation by macrophages.

The induction of pathogenic immune responses may be dependent on the immune system receiving 'danger' signals resulting from tissue damage, rather than tolerogenic stimuli associated with normal cell turnover. The aim was to test this hypothesis by comparing the effects of the uptake of necrotic and apoptotic cells on the ability of antigen-presenting cells (APC) to stimulate immune responses in vitro. The experiments focused on presentation by the macrophage, which is the main cell type adapted for clearing cellular debris in vivo. Murine bone marrow-derived macrophages were pulsed with neutrophils that had been rendered apoptotic or necrotic, and tested for the ability to induce T cell responses. The macrophages that had taken up necrotic, but not apoptotic, cells were able to stimulate recall proliferation by ovalbumin-specific T cells. Furthermore, the response to the mitogen concanavalin A (Con A) was more than 6 times higher when macrophages had been pulsed with necrotic, in comparison with apoptotic, cells. In control experiments, macrophages that had not been exposed to dying neutrophils stimulated weak responses to ovalbumin and Con A. To determine why the uptake of apoptotic and necrotic cells exert opposing effects on the ability of macrophages to stimulate T cells, the expression of costimulatory molecules by treated macrophages, and their production of potentially immunomodulatory cytokines were measured. Flow cytometry revealed that macrophages that had taken up necrotic, but not apoptotic, neutrophils expressed increased levels of CD40 compared to untreated controls within 4 h. Macrophages pulsed with apoptotic cells secreted higher levels of transforming growth factor-beta1 than those ingesting necrotic cells or untreated controls. Our interpretation of these results is that macrophages that have taken up necrotic cell debris present antigens to T lymphocytes with greater efficiency due to transient CD40 upregulation, whereas those that have ingested apoptotic cells are ineffective APC since they secrete inhibitory cytokine.

Animals↗
PubMed1998

Initial cytokine exposure determines function of macrophages and renders them unresponsive to other cytokines.

The functional properties of infiltrating macrophages (Mphi) must be tightly regulated to facilitate appropriate responses to complex conditions in an inflammatory focus. This study was designed to ascertain whether uncommitted Mphi that have been exposed to combinations of cytokines with opposing functions develop properties dictated by one cytokine or by cytokine mixtures. Uncommitted rat bone marrow-derived Mphi (BMDMs) were incubated with IFN-gamma, TNF-alpha, TGF-beta, IL-4, IL-6, and IL-10 alone or sequentially in combinations. After 48 h, function was assessed by nitric oxide (NO) generation, uptake of apoptotic neutrophils, and beta-glucuronidase expression. IFN-gamma followed 4 h later by TNF-induced NO generation. The pretreatment of BMDMs before IFN-gamma priming with TNF, TGF-beta, and IL-4 suppressed NO generation by 87%, 92%, and 85%, respectively; IL-10 had no effect. The same cytokines administered at 4 h after IFN priming had no effect on NO generation. The uptake of apoptotic polymorphonuclear leukocytes was augmented by TNF (40% vs 29% controls; p < 0.05) and decreased by IFN-gamma, IL-10, and IL-4. The TNF response was unaffected by subsequent treatment with IFN-gamma, IL-4, or IL-10. Similarly, the decreased polymorphonuclear leukocyte uptake induced by IFN-gamma, IL-4, or IL-10 was unaffected by the subsequent addition of TNF. Beta-glucuronidase expression was increased by TGF-beta and decreased by IFN-gamma. These responses were not modified by cytokines with the opposing function. Thus, the functional response of BMDMs to complex mixtures of cytokines was determined by the first cytokine to which they were exposed. Once activated, BMDMs become unresponsive to alternative activating signals, a finding which has obvious implications for Mphi function in vivo.

Animals↗
PubMed1998

Presentation of the Goodpasture autoantigen to CD4 T cells is influenced more by processing constraints than by HLA class II peptide binding preferences.

Class II molecules are believed to influence immune responses by selectively binding antigen-derived peptides for recognition by T cells. In Goodpasture's (anti-glomerular basement membrane) disease, autoimmunity to the NC1 domain of the alpha3-chain of type IV collagen (alpha3(IV)NC1) is strongly associated with HLA-DR15. We have examined the influence of the peptide binding preferences of DR15 molecules on the selection of alpha3(IV)NC1-derived peptides displayed bound to DR15 molecules on the surface of alpha3(IV)NC1-pulsed DR15-homozygous Epstein-Barr virus-transformed human B cells. The preferences of DR15 molecules were investigated using a panel of 24 overlapping peptides spanning the sequence of alpha3(IV)NC1. The alpha3(IV)NC1-derived peptides selected for display to T cells were determined by biochemical analysis as reported previously (Phelps, R. G., Turner, A. N., and Rees, A. J. (1996) J. Biol. Chem. 271, 18549-18553). Three nested sets of naturally presented alpha3(IV)NC1 peptides were detectable bound to DR15 molecules. Peptides representative of each nested set bound to DR15 molecules, but almost two-thirds of the alpha3(IV)NC1 peptides studied had as good or better DR15 affinity than those identified as naturally processed. Thus alpha3(IV)NC1 presentation to T cells is determined more by "processing factors" than by the preferences of relatively indiscriminate DR15 molecules. The results have important implications for the use of class II peptide binding data to aid identification of potential T cell epitopes, especially for antigens which, like alpha3(IV)NC1, contain many sequences able to bind class II molecules.

Amino Acid Sequence↗