Search PubMed⌕ Search

Biomedical subjects

M R Daha

Publications and source records attributed to M R Daha.

At least 163 records · Page 9Linked to original sources
PubMed1995

Active Heymann nephritis in complement component C6 deficient rats.

The mechanisms of renal injury that result in proteinuria in active Heymann nephritis (AHN) remain unclear, though data suggest that in analogy of the passive form of the disease the membrane attack complex C5b-9 may be involved. AHN was induced in an inbred strain of PVG/c-rats that are totally deficient in the C6 component of complement and are unable to form the lytic C5b-9 complex, as well as in non-complement deficient PVG/c+ rats that are immunologic identical to the deficient strain. In both groups of animals comparably high titers of anti-Fx1A autoantibodies were found after three weeks and persisted at 40 weeks. Proteinuria was also similar in both groups, and was first evident at six weeks. High levels of urinary protein, ranging from 200 mg/24 hr to 500 mg/24 hr, were found after 10 weeks and persisted up to one year. Renal biopsy findings at various times post-immunization were identical in both groups, including immunofluorescence staining for Ig and C3 deposits, and also EM findings of subepithelial electron-dense deposits were not different. The injection of heterologous rabbit complement, that partially and temporarily restored the CH50 activity in PVG/c- rats did not alter or hasten the disease. Long-term follow-up showed that all rats in both groups continued to have severe proteinuria and that most animals died between 8 to 12 months after disease induction, without renal impairment. EM findings in serial biopsies demonstrated that the growth of the subepithelial deposits as measured by surface area occurred between weeks 4 and 12. A positive correlation (r = 0.94) between the size of the deposits and the level of proteinuria was found. These studies demonstrate that the membrane attack complex of complement does not play a major role in AHN. The relationship of the size of the immune deposits to the level of proteinuria suggests that the growth of the immune deposits on itself initiate secondary mechanisms that damage the permselective characteristics of the glomerular membrane.

Animals↗
PubMed1995

Decreased frequency of HLA-DR13DR6 in Wegener's granulomatosis.

The pathogenesis of Wegener's granulomatosis, microscopic polyangiitis and idiopathic rapidly progressive glomerulonephritis (RPGN) is still unclear; in vitro data support both humoral and cellular autoimmune mechanisms. An association of Wegener's granulomatosis with HLA antigens has been described, with conflicting results concerning the antigens involved. We have performed serological HLA typing of patients at two different laboratories within the Netherlands (N = 118 and N = 106,N respectively). A significant decrease in the frequency of HLA-DR13DR6 was present in both patient groups in comparison to controls (chi 2 = 21.9; corrected P value < 0.004 for both groups together). There were no differences in the distribution of HLA-antigens between patients with Wegener's granulomatosis and microscopic polyangiitis, between cANCA (cytoplasmic anti-neutrophil cytoplasmic antibodies) and pANCA (perinuclear ANCA, anti-MPO) positive patients, and between patients with and without relapsing disease.

Aged↗
PubMed1995

Production and cytokine-mediated regulation of monocyte chemoattractant protein-1 by human proximal tubular epithelial cells.

Impairment of renal function in various types of glomerular disease is associated with tubulointerstitial changes. The mechanism of mononuclear cell infiltration in the interstitium is not fully understood. Recently, monocyte chemoattractant protein-1 (MCP-1) has been identified as a monocyte-specific chemotactic factor. We analyzed the presence of MCP-1 in renal biopsies from patients with various forms of glomerular disease and demonstrated that MCP-1 expression is increased in renal tubular epithelial cells during disease. Further analysis showed that various cell lines of human proximal tubular epithelial cells (PTEC) produce MCP-1 in culture under serum-free conditions and that the production is inhibited by cycloheximide. IL-1 alpha and TNF-alpha enhanced the production by each cell line in a dose- and time-dependent manner as measured by radioimmunoassay. Northern blot analysis demonstrated that IL-1 alpha and TNF-alpha markedly enhanced the expression of MCP-1 mRNA. Taken together these observations support the notion that MCP-1 is synthesized de novo by PTEC. MCP-1 produced by PTEC is found to be 13 kD by gel filtration chromatography. It is chemotactically active for monocytes. We conclude that in various types of glomerular disease, MCP-1 expression in tubular epithelial cells is associated with up-regulation of MCP-1 production by PTEC. These findings raise the possibility that macrophages may accumulate in renal interstitium as a consequence of MCP-1 production by PTEC.

Biopsy↗
PubMed1995

Glomerulopathy induced by a single monoclonal autoantibody against GP330.

Monoclonal autoantibodies were obtained from Lewis rats with active Heymann nephritis. Two cloned rat/mouse hybridomas, 3D9B and 5B8C, that secreted rat IgG2a autoantibodies were selected for their ability to react with gp330 in ELISA and propagated further. Their specificity was confirmed by immunoprecipitation of crude antigens from a yolk sac carcinoma cell line expressing gp330. The size of the precipitated molecule was identical to that immunoprecipitated by previously described anti-gp330 antibodies. Indirect immuno-electron microscopy showed that 3D9B exclusively stained the intermicrovillous areas of the tubular brush border membrane, while 5B8C stained the full tubular microvillous membrane and the glomerular epithelial coated pits. Passive transfer of 3D9B did not induce Ig deposits or functional renal damage within 7 days. However, injection of 5B8C caused granular glomerular deposits within 1 h, subepithelial immune aggregates within 6 days and antibody deposition on the brush border within 7 days. Only ascites production of clone 5B8C in rats, but not in mice, caused subepithelial immune deposits and abnormal proteinuria. This study shows that a single monoclonal autoantibody to gp330 is able to induce a mild form of Heymann nephritis.

Animals↗
PubMed1995

Cell-mediated autoimmunity in patients with Wegener's granulomatosis (WG)

Despite the well described infiltration of cells of the cellular immune system in vasculitic lesions and the granuloma formation in patients with WG, the role of T cell-mediated autoimmunity in WG is not clear. Reports of T cell proliferation in response to neutrophil azurophilic granule proteins are contradictory. In this study we have assessed the proliferation of T cells of WG patients to purified proteinase 3 (PR3) and to total azurophilic granule proteins in two different assays. In addition to the classical proliferation assay with isolated peripheral blood mononuclear cells, we have used a whole blood proliferation assay. In both assays we found proliferative responses to PR3 in patients with WG. The number of patients reacting to the azurophilic granule extract was higher than the patients reacting to the purified PR3, suggesting that other autoantigens may also be involved. We have identified epitopes of PR3 that may be potential targets of class I-restricted T cell responses in the context of HLA-A*0201, the most common MHC class I molecule. These epitopes were determined by the binding of synthetic PR3 peptides to HLA-A*0201 on the antigen-processing defective cell line, T2. In addition, T cell lines were established from tissue biopsies, obtained from WG patients, and assessed for cytolytic reactivity against T2 cells, preloaded with synthetic PR3 peptides. We conclude that T lymphocytes of WG patients have increased proliferative responses to purified PR3 and to a larger extent to non-fractionated proteins of azurophilic granules of polymorphonuclear neutrophilic leucocytes (PMN).

Amino Acid Sequence↗
PubMed1995

Fulminant meningococcal septic shock in a boy with combined inherited properdin and protein C deficiency.

A 7-year-old patient with fulminant septic shock due to Neisseria meningitidis of the uncommon serogroup Y developed extensive gangrene of the limbs. Multiple amputations were necessary and a pulmonary embolism occurred within 2 days post-operatively. Complement and haemostatic system studies, done after recovery, showed a complete absence of properdin antigen and a low protein C antigen and activity level in plasma. Defective haemolytic activity in gel by the alternative pathway of complement activation could be restored with purified properdin, indicating a properdin deficiency type 1. Protein C antigen level as well as activity were in agreement with a protein C deficiency type I. The polymerase chain reaction (PCR) product of exon five of the protein C gene showed a substitution of 72Gly by Arg. Both deficiencies were traced among relatives of the patient. Serum of the father of the patient's mother was also properdin-deficient. Microsatellite haplotyping of the X-chromosome of the patient and his relatives showed that a distinct haplotype cosegregated with the properdin deficiency (Lodscore 2.25; four informative meioses). The protein C type I deficiency was present in the patient's mother and her mother and cosegregated with the mutation found. So far as is known, this is the first patient described with combined inherited properdin deficiency and protein C deficiency.

Adult↗
PubMed1995

The influence of tetracyclines on T cell activation.

Minocycline has been shown to have an anti-inflammatory effect in patients with rheumatoid arthritis (RA). Since there is evidence that RA is a T cell-mediated disease, we investigated the effect of minocycline on human T cell clones derived from the synovium of an RA patient. The T cells, when activated via the T cell receptor (TCR)/CD3 complex, were suppressed functionally by minocycline, resulting in a dose-dependent inhibition of T cell proliferation and reduction in production of IL-2, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha). Besides an inhibition of IL-2 production, minocycline exerted its effect on T cell proliferation by induction of a decreased IL-2 responsiveness. We showed that the chelating capacity of minocycline plays a crucial role in the inhibitory effect on T cell function, since the inhibitory effect on T cell proliferation could be annulled by addition of exogenous Ca2+. However, minocycline did not markedly influence the typical TCR/CD3-induced intracellular Ca2+ mobilization. Taken together, the results clearly indicate that minocycline has immunomodulating effects on human T cells.

Anti-Bacterial Agents↗
PubMed1995

Endothelial cells and renal epithelial cells do not express the Wegener's autoantigen, proteinase 3.

Proteinase 3 (PR3) is the major antigen for autoantibodies (C-ANCA) against cytoplasmic components of neutrophils which are strongly associated with Wegener's granulomatosis (WG). Recent data that PR3 may be expressed by renal tubular epithelial cells and endothelial cells suggest potential for a direct pathogenic effect against these cells by C-ANCA or cytoxic T lymphocytes. Using a semi-quantitative polymerase chain reaction (PCR), ELISA and indirect immunofluorescence staining we studied endothelial and epithelial cell PR3 expression. By PCR, no PR3 expression was found in human umbilical vein endothelial cells (HUVEC) either untreated, or when treated with interferon-gamma (IFN-gamma) (200 U/ml, 6 h, 24 h), IL-1 (20 U/ml, 6 h), tumour necrosis factor-alpha, (TNF-alpha) (200 U/ml, 0, 1, 2, 4, 6 h) or IFN-gamma + TNF-alpha (6 h); iliac vein and artery endothelial cells did not express PR3 either. In contrast, PR3 was detected in HL60 cells and neutrophils by PCR, expression being confirmed by sequence analysis. Three PR3 MoAbs showed no binding to unstimulated or TNF-alpha-stimulated HUVEC either by ELISA or by indirect immunofluorescence staining. The epithelial cell line A549 expressed PR3 when assayed by PCR. However, three renal epithelial cell lines (two tubular and one glomerular) showed little or no PR3 expression by PCR or ELISA. These studies fail to demonstrate evidence for PR3 expression by endothelial cells, even when using the highly sensitive PCR assay. Whilst PR3 expression by A549 cells is intriguing, the relevance of this in the pathology of WG is doubtful considering the negligible expression by renal epithelial cell lines.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1995

Chloroquine inhibits T cell proliferation by interfering with IL-2 production and responsiveness.

Chloroquine (Chl) is an anti-rheumatic drug that is widely used in the treatment of rheumatoid arthritis (RA). It seems that T cells are important in the pathogenesis of RA, but it is not known whether Chl acts via inhibition of T cell function. We here present evidence that Chl, just like cyclosporine A (CsA), inhibits T cell proliferation as induced with immobilized alpha CD3 MoAb in a concentration-dependent manner, at least partly through interfering with the production of IL-2 protein and the induction of IL-2 mRNA. Furthermore, Chl impedes the responsiveness of T cell clones to IL-2 since (1) the inhibition of alpha CD3 MoAb-induced proliferation by Chl could not be reversed by rIL-2 and (2) Chl directly blocks IL-2-driven proliferation of cloned T cells. Chl appeared to interfere with the internalization (50% inhibition) and degradation (total blockade) of rIL-2. Finally, the combination of Chl and CsA synergistically inhibited T cell proliferation. We conclude that Chl may inhibit functional properties of human T cells, although the drug is 100- to 1000-fold less potent than CsA in inhibiting T cell proliferation and IL-2 production, respectively. It is speculated that the in vitro effects of Chl might be relevant in explaining the anti-rheumatic effect of this drug in patients with RA.

Antibodies, Monoclonal↗
PubMed1995

Subclass distribution of IgA and IgG antibodies against Clq in patients with rheumatic diseases.

To obtain insight into the immunoregulatory mechanisms in patients with different rheumatic diseases, the occurrence and the subclass distribution of IgA and IgG antibodies against Clq (anti-ClqAb) was determined. In patients with systemic lupus erythaematosus (SLE) the highest frequency of increased serum levels of IgG anti-ClqAb were found, whereas IgA anti-ClqAb were predominantly present in patients with ankylosing spondylitis (AS) and patients with rheumatoid arthritis complicated by vasculitis (RV). In all the IgA anti-ClqAb positive AS and RV patients the antibody reactivity involved the IgA1 subclass while the IgA2 subclass was found in 47% of the patients. Further characterization of the IgA anti-Clq binding activity in sera of AS patients revealed that both subclasses of IgA anti-ClqAb were predominantly polymeric; the binding of both IgA subclasses with solid phase Clq was inhibitable by aggregated fluid phase Clq; we found no detectable interference of rheumatoid factor in the test system for the measurement of IgA anti-ClqAb. In patients with SLE the IgG anti-ClqAb reactivity was mainly of the IgG2 and IgG3 subclass, whereas in the same patients the IgG anti-tetanus toxoid response was not restricted to these subclasses. The predominance of IgG2 and IgG3 subclass of anti-ClqAb in sera of SLE patients, suggests a skewing of the anti-ClqAb response. The observation that the IgA anti-ClqAb of both subclasses is predominantly polymeric in nature and the notion that polymeric IgA is associated with activation of inflammation cascades, suggests that IgA anti-ClqAb may contribute to tissue damage.

Antibodies, Monoclonal↗
PubMed1995

S fimbriae of uropathogenic Escherichia coli bind to primary human renal proximal tubular epithelial cells but do not induce expression of intercellular adhesion molecule 1.

We have recently reported an increase of expression of the intercellular adhesion molecule 1 by renal carcinoma cells in response to S fimbriae of Escherichia coli. Now we demonstrate that E. coli expressing S and P fimbriae strongly binds to human proximal tubular epithelial cells. However, in primary and simian virus 40-transfected renal tubular epithelial cells S fimbriae do not enhance the expression of intercellular adhesion molecule 1.

Bacterial Adhesion↗
PubMed1995

Joint-derived T cells in rheumatoid arthritis proliferate to antigens present in autologous synovial fluid.

The histopathological features of rheumatoid joint-inflammation suggest that an antigen-driven activation of T cells plays a central role in the onset and/or perpetuation of the inflammatory process. However, the disease-associated antigens responsible for the activation of T cells in the joint are unknown. In this project we study the response of IL-2 expanded T-cell lines from the synovial fluid (SF) of rheumatoid arthritis (RA) patients against autologous SF in a proliferation assay. Sixteen out of 32 RA patients were found to have CD4+ T cells that proliferate in response to autologous SF. The presence of T cells able to respond to SF antigens in inflamed joints suggests that these T cells play an active role in the pathogenesis of RA. T cell clones reactive to autologous SF were isolated from SF-derived T-cell lines of two RA patients. All clones were of the CD4+, CD8-, alpha/beta+ phenotype. SF-reactivity of T-cell clones from the DR4/DR12-positive RA patient was restricted via the Dw4 subtype of DR4. SF reactivity of T cells of the DR12/DR15 patient was DP-restricted. Some of the T-cell clones responded specifically to autologous and not to allogeneic SF, whereas others revealed responsiveness against a limited number of allogeneic SF samples. The (restricted) specificity of T cells towards autologous SF antigens is indicative for heterogeneity of the epitopes recognized and argues against ubiquitous nonpolymorphic joint constituents as the relevant antigens recognized by the SF-autoreactive T cells.

Arthritis, Rheumatoid↗
PubMed1995

Rheumatoid factor production in the joint.

Mononuclear cells derived from bone marrow, synovium and peripheral blood of patients with rheumatoid arthritis (RA) were examined for their capacity to produce rheumatoid factor (RF) in order to investigate the origin of circulating RF. The results demonstrate that mononuclear cells derived from bone marrow are able to produce IgG-, IgA- and IgM-RF and that the amounts of RF produced by bone marrow cells are not significantly different from that by dissociated synovial cells. Since circulating immunoglobulins are mainly derived from the bone marrow this observation suggests that also RF circulating in RA patients mainly originates from the bone marrow.

Arthritis, Rheumatoid↗
PubMed1995

The involvement of Kupffer cells and liver endothelial cells in the clearance of large sized soluble IgA aggregates in rats.

These findings suggests that AIgA is bound both by KC and EC in normal situations. Because of the great phagocytic capacity of KC, the contribution of EC in handling AIgA in normal rats is minimal. However, when KC are defect or absent (as after Cl2MDP treatment), the handling of AIgA by EC may become of mayor importance, i.e. it will take over the phagocytic function of KC. Studies concerning a possible receptor on EC involved in binding of AIgA are in progress.

Animals↗
PubMed1995

Complement in serum and dialysate in children on continuous ambulatory peritoneal dialysis.

OBJECTIVE: During continuous ambulatory peritoneal dialysis (CAPD), activation of complement in the peritoneal cavity may theoretically occur, with inappropriately high or low levels of certain complement factors in dialysate as a consequence. In a group of children on CAPD, it was tested whether levels of a number of complement factors in dialysate were in the range that was predicted on the basis of their molecular weight. DESIGN: Serum and dialysate levels of C1q, C3, C4, C3d, B, D, and P were measured after a night dwell in children on CAPD. Simultaneously, four non-complement proteins (beta 2-microglobulin, albumin, IgG, and alpha 2-macroglobulin) were also measured in dialysate and serum. Assuming a linear relationship between the log base 10 of the dialysate/serum ratio of these non-complement proteins and the log base 10 of their molecular weight, the expected ratios of all complement factors were determined. The differences between actual and predicted ratios were tested using a modified t-test, taking into account the inaccuracy of the estimate. SETTING: University hospital. PATIENTS: A group of 14 children on CAPD, with a median age of 7.8 years (range 2.1 - 13.2). These children had been on CAPD for a median period of 42.4 months (range 0.4 - 89.1). RESULTS: The ratios of factor D (p < 0.001) and C3d (p = 0.035) were elevated, whereas those of C3 (p < 0.001), C4 (p < 0.001), and factor P (p = 0.012) were decreased. CONCLUSIONS: Relatively low dialysate/serum ratios of C4, C3, and factor P could be caused by intraperitoneal consumption of complement. High levels of C3d are compatible with this. High dialysate/serum ratios of factor D indicate intraperitoneal production of factor D. These results provide evidence for activation of complement in the peritoneal cavity in children on CAPD. A further reduction of already low levels of complement factors in dialysate as a result of this may impair host defense.

Albumins↗
PubMed1995

Evaluation by histology, immunohistology and PCR of protocollized renal biopsies 1 week post-transplant in relation to subsequent rejection episodes.

Renal biopsies were performed 1 week following renal transplantation at a time without clinical evidence of rejection in 43 patients (13 females, mean age 48 years range 18-60 and 30 males, mean age 43 years range 17-59 years). Thirty-six biopsies were available for histological or immunohistochemical analysis. Immunohistochemical analyses were performed with monoclonal antibodies against leukocytes (CD45), monocytes (WT14), complement factor 3 (C3), T-cells (Leu4), T-cell receptor alpha beta and gamma delta, tumour necrosis factor alpha (TNF alpha), IL-2 receptor (IL2-R, TAC), intercellular adhesion molecule-1 (ICAM1) and HLA-DR. The slides were scored semiquantitatively with the observers having no knowledge of clinical or patient data. TNF alpha and IL-2R were also measured by quantative PCR. None of the studied parameters correlated to delayed graft function or graft loss. Histological analysis showed that both focal interstitial infiltrate (18/35) and tubular basement membrane disruption (11/35) were followed by a higher incidence of subsequent rejection (P = 0.03 and 0.02 respectively). Also positivity for WT14 around tubuli (P = 0.02) was associated with subsequent occurrence of rejection. The intensity of staining of ICAM-1 on PTC as well as TAC on proximal tubular cells was associated with the number of subsequent rejection episodes. The association between the IL-2 receptor and subsequent rejection was also found applying PCR to the tissue specimens. We conclude that the presence of focal interstitial infiltrates and tubulitis in 1-week biopsies from well-functioning grafts carries an increased risk of subsequent rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Isopropylmalate Synthase↗
PubMed1995

A novel rat mesangial matrix protein, MMP-50/100, involved in mesangial glomerulopathies.

BACKGROUND: Within the glomerular extracellular matrix, the glomerular basement membrane and the mesangial matrix have different compositions, presumably related to their different functions. In this study, a novel mesangial matrix protein is recognized by mAb ED5 and KiM4R, which were originally selected for reactivity with follicular dendritic cells of rat lymphoid organs. EXPERIMENTAL DESIGN: Distribution of this mesangial matrix protein (MMP-50/100) was studied in normal Wistar rat kidneys by indirect immunofluorescence and immunoelectron microscopy. For partial immunobiochemical characterization, ED5-affinity-purified glomerular matrices were subjected to SDS-PAGE analysis. Expression of MMP-50/100 was additionally studied in kidneys of rats depleted for complement and in kidneys of rats depleted for resident macrophages. Functional significance of MMP-50/100 was studied in kidneys of rats with mesangial glomerulopathies. RESULTS: Immunoelectron microscopy showed that MMP-50/100 is located in the extracellular matrix of the rat renal mesangium between mesangial cells and the basement membrane and on the mesangial cell membrane. SDS-PAGE analysis of affinity-purified glomerular matrices indicated that MMP-50/100 is a polypeptide glycoprotein with chains of apparent molecular weights of 50 and 100 kDa. Both in vivo and in vitro results indicate that MMP-50/100 does not appear to be a complement factor, or an Fc or complement receptor. In rats partially depleted for resident macrophages, the expression of MMP-50/100 was similar to that in control rats. In rats with BSA-induced chronic serum sickness nephritis, in rats with anti-Thy-1 nephritis, and in rats with uninephrectomy-induced focal glomerular sclerosis, the mesangial expression of MMP-50/100 was significantly increased. In the first model, double-label immunofluorescence demonstrated identical localization of MMP-50/100 with mesangial immune complex deposits. CONCLUSIONS: We conclude that MMP-50/100 is an intrinsic component of the mesangial matrix, presumably related to the "classic" mesangial cell. Expression of MMP-50/100 is increased in expanded mesangial matrices during development of glomerular disease. Furthermore, MMP-50/100 appears to be involved in the handling of mesangial immune complexes.

Animals↗