Search PubMed⌕ Search

Biomedical subjects

D Adu

Publications and source records attributed to D Adu.

At least 55 records · Page 3Linked to original sources

Examination of two genetic polymorphisms within the renin-angiotensin system: no evidence for an association with nephropathy in IDDM.

Premature cardiovascular disease is common in insulin-dependent diabetic (IDDM) patients who develop diabetic nephropathy. Genetic polymorphism within the renin-angiotensin system has been implicated in the aetiology of a number of cardiovascular disorders; these loci are therefore candidate genes for susceptibility to diabetic renal disease. We have examined the angiotensin converting enzyme insertion/deletion polymorphism and angiotensinogen methionine 235 threonine polymorphism in a large cohort of Caucasian patients with IDDM and diabetic nephropathy. Patients were classified as having nephropathy by the presence of persistent dipstick positive proteinuria (in the absence of other causes), retinopathy and hypertension (n = 242). Three groups were examined for comparison: ethnically matched non-diabetic subjects (n = 187); a geographically defined cohort of newly diagnosed diabetic patients (n = 341); and IDDM patients with long duration of disease (> 15 years) and no evidence of overt nephropathy (n = 166). No significant difference was seen in distribution of angiotensin converting enzyme or angiotensinogen genotypes between IDDM patients with nephropathy and recently diagnosed diabetic subjects (p = 0.282 and 0.584, respectively), nor the long-duration non-nephropathy diabetic subjects (p = 0.701 and 0.190, respectively). We conclude that these genetic loci are unlikely to influence susceptibility to diabetic nephropathy in IDDM in the United Kingdom.

Adult↗

IL-1 beta production by human polymorphonuclear leucocytes stimulated by anti-neutrophil cytoplasmic autoantibodies: relevance to systemic vasculitis.

Neutrophils accumulate in the acute blood vessel lesions of patients with autoimmune systemic vasculitis. They have been shown previously to produce the cytokine IL-1 beta in response to stimulation with TNF. This study demonstrates that neutrophils can be stimulated by anti-neutrophil cytoplasmic antibodies (ANCA), which are present in patients with systemic vasculitis, to express mRNA and protein for IL-1 beta. Both human ANCA and MoAbs to a variety of autoantigens recognized by ANCA, including proteinase 3, myeloperoxidase, bactericidal/permeability increasing protein and elastase, are effective. This response can be inhibited by actinomycin and cycloheximide, suggesting a requirement for de novo protein synthesis. IL-1 beta production can be inhibited by pooled human intravenous immunoglobulins but not by FK506 or cyclosporin A. These data suggest that ANCA in patients with active vasculitis may stimulate neutrophils to produce cytokines. It is hypothesized that cytokine production from neutrophils that accumulate in significant numbers in vasculitic lesions contribute to and augment the local inflammatory response by the activation of vascular endothelial cells and infiltrating leucocytes.

Antibodies, Antineutrophil Cytoplasmic↗

Glomerular vascular cell adhesion molecule-1 expression in renal vasculitis.

AIMS: To study the expression of cell adhesion molecules in the renal biopsy specimens of patients with systemic vasculitis and Henoch-Schönlein purpura (HSP); to correlate this with the severity of glomerular inflammation. METHODS: Renal biopsy specimens obtained from eight patients with untreated systemic vasculitis (four with Wegener's granulomatosis and four with microscopic polyarteritis), eight with HSP and nine controls (four with normal histopathology and five with thin glomerular basement membrane disease) were stained using the alkaline phosphatase anti-alkaline phosphatase method with monoclonal antibodies directed against intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin. RESULTS: Biopsy specimens of normal kidneys expressed ICAM-1 in glomerular endocapillary cells, Bowman's capsule epithelium, interstitial cells and interstitial vascular endothelium, and VCAM-1 in Bowman's capsule epithelium, proximal tubular epithelium and interstitial vascular endothelium. No staining with antibody directed against E-selectin was seen in any of the biopsy specimens. Biopsy specimens of patients with a vasculitic glomerulonephritis (segmental necrotising glomerulonephritis) expressed VCAM-1 in glomerular endocapillary cells (four of eight patients with systemic vasculitis; two of eight patients with HSP). In patients with a systemic vasculitis glomerular VCAM-1 expression was associated with a more severe renal lesoin (44, 50, 60, and 65% of glomeruli involved) than in those not showing glomerular VCAM-1 expression (3, 3, 11, and 39% of glomeruli involved). CONCLUSION: Expression of VCAM-1 by glomerular endocapillary cells in renal biopsy specimens raises the possibility that recruitment of VLA-4 bearing leucocytes may contribute to glomerular injury in Wegener's granulomatosis and microscopic polyarteritis.

Adolescent↗

Hemodialysis in the treatment of acute renal failure in tropical Africa: a 20-year review at the Korle Bu Teaching Hospital, Accra.

From 1972 to 1992, 170 patients with acute renal failure (87 M, 83 F; mean age 32.51 +/- SE 0.945) underwent hemodialysis at the renal unit of the Korle Bu Teaching Hospital, Accra. Vascular access was established initially by arteriovenous shunt (133 cases), femoral venous cannulation (10 cases), and subclavian vein cannulation (27 cases). The overall mortality for acute renal failure (ARF) was 31.8% (54/170). The mortality for obstetric cases was 43.7% (14/32); for surgical cases, 33.3% (6/18); medical cases, 28.3% (13/32); and gynecologic (posthysterectomy) cases, 28.3% (2/7). The most important causes of death in ARF were pulmonary edema (42%), sepsis (20%), and cardiac tamponade (10.4%). Hemodialysis is now established as a form of treatment for ARF and a overall survival rate of 68.2% justifies the development of our program. With improvement of economies of developing countries and health insurance schemes, this form of treatment should be available in all developing countries.

Acute Kidney Injury↗

Blackwater fever and acute renal failure in expatriates in Africa.

From September 1976 to July, 1993, 7 patients---5 Europeans, 1 Filipino national, and 1 Korean---were admitted to the Renal Unit of Korle Bu Teaching Hospital in Ghana with acute renal failure due to severe malaria and intravascular hemolysis. All these patients had been in the Tropics 3 to 8 weeks and none were no malarial prophylaxis. All needed dialysis because of severe uremic symptoms. Four patients survived and 3 died. It is recommended that nationals from nonmalarial countries be counselled on the extreme importance of malarial prophylaxis when visiting Tropical areas where malaria is endemic.

Acute Kidney Injury↗

Low calcium dialysate and hyperparathyroidism.

A low calcium dialysate reduces hypercalcemia from calcium-containing phosphate binders and makes phosphate control possible without the use of aluminum salts. We asked whether this might, however, lead to hyperparathyroidism. We prospectively studied serum concentrations of parathyroid hormone levels (by an immunoreactive intact molecule assay) in 173 patients on continuous ambulatory peritoneal dialysis (CAPD) who were started on a low calcium dialysate (Ca2+ 1.25 or 1.00 mmol/L) because of hypercalcemia. Median follow-up was 13.2 months (range 1-28). Initial serum parathyroid hormone was [median(range)]: 70(5-1043) ng/L pre low calcium dialysate, and this rose to 130(5-914) ng/L at 0-6 months; 130(5-1030) ng/L at 6-12 months; 170(170-1400) ng/L at 12-18 months; and 130(5-1200) ng/L at 18-24 months (p = 0.0006). Twenty-two patients required a parathyroidectomy because of a sustained rise in parathyroid hormone that was not responsive to alfacalcidol and hypercalcemia. Initial serum parathyroid hormone was significantly higher in these patients at 359 (5-1073) ng/L as compared to a level of 69.5 (6-1147) ng/L in patients who did not have a parathyroidectomy (p = 0.0009). There was a significant sustained fall in mean serum corrected calcium from 2.77 (2.37-3.51) mmol/L to 2.53 (1.39-3.20) mmol/L at three months (p = 0.0006), a nonsignificant rise in mean serum alkaline phosphate from 179 (47-1858) mmol/L to 191 (55-1821) mmol/L (p = 0.15), and a fall in mean serum phosphate levels from 1.87 (0.59-3.18) mmol/L to 1.68 (0.45-3.6) mmol/L (p = 0.76). Our data suggest that the benefits of a low calcium dialysate in CAPD patients are balanced by an increased risk of hyperparathyroidism, and that this risk is higher in patients with an initially high serum parathyroid hormone level.

Adult↗

Soluble circulating cell adhesion molecules in haemolytic uraemic syndrome.

Plasma concentrations of soluble vascular cell adhesion molecule-1 (sVCAM-1), E-selectin (sE-selectin) and intercellular adhesion molecule-1 (sICAM-1) were measured by enzyme-linked immunosorbent assay in four groups of children. Group 1 consisted of 20 patients with acute diarrhoea-associated haemolytic uraemic syndrome (D+HUS), the aetiology of HUS being verocytotoxin-producing Escherichia coli infection in each case. Controls consisted of 11 patients who had previously had D+HUS (group 2), 12 with chronic renal failure (group 3) and 8 healthy controls (group 4). When compared with healthy controls, the acute D+HUS group had higher sVCAM-1 (median 1,875 ng/ml, range 1,200-6,450 ng/ml vs. 1,200 ng/ml, range 975-2,125 ng/ml), von Willebrand factor antigen, (1.9 U/ml, range 0.85-5.1 U/ml vs. 0.55 U/ml, range 0.3-1.57 U/ml), white cell count (WBC, 14.5 x 10(9)/l, range 7.8-43.1 10(9)/l vs. 8.9 10(9)/l, range 5.7-10.8 10(9)/l) and neutrophil count (PMN, 10.1 x 10(9)/l, range 4.3-26.5 10(9)/l vs. 4.3 10(9)/l, range 3.7-6.6 10(9)/l), all P < 0.005, and sICAM-1 was reduced (230 ng/ml, range 130-340 ng/ml vs. 400 ng/ml, range 260-690 ng/ml), P < 0.05. Within the acute D+HUS group there was a significant correlation between sICAM-1 and PMN (r = 0.56, P < 0.01). There was no correlation between any adhesion molecule and plasma creatinine or von Willebrand factor. Comparing the acute HUS group with children with chronic renal failure, WBC (P < 0.001), PMN (P < 0.01) and sVCAM-1 (P < 0.01) were significantly elevated, but there was no difference between the von Willebrand factor (P = 0.08) or the sICAM-1 (P > 0.1). sVCAM-1 is elevated and sICAM-1 decreased in acute D+HUS. This pattern of altered adhesion molecule concentration is unlike that in adults with vasculitis and suggests that different endothelial regulatory factors are at play.

Acute Disease↗

Anti-epithelial (anti-A549) antibodies: their nature, specificity and relevance to transplantation.

Several studies have addressed the possible importance of anti-epithelial cell antibodies in kidney transplantation using the A549 cell line as an in vitro model. In this paper we report our results using for the first time an enzyme-linked immunosorbent assay (ELISA) to detect the anti-A549 cell antibodies. Sera from 129 kidney transplant patients were tested for IgM anti-epithelial cell antibodies directed against the A549 cell line prior to transplantation; only three sera were positive (2.3%). 101 of these patients were then followed-up post-transplantation; sera were collected routinely at 2, 6 and 12 weeks and at the time of rejection episodes. All samples were also tested for cytomegalovirus (CMV) IgM antibodies. Sixteen patients developed anti-A549 IgM antibodies, and there was no correlation with acute graft rejection. Anti-epithelial antibodies showed no binding to sections of normal kidney or biopsies of rejected kidneys. Eleven patients were positive for anti-CMV IgM antibodies. In nine cases both IgM anti-A549 and IgM anti-CMV antibodies were found, which was a highly significant association (p < 0.001). Analysis of A549 cellular proteins by immunoblotting gave evidence for the presence of CMV polypeptides in the cell lysate. Electron-microscopic examination of A549 cell preparations revealed intracellular particles which were compatible in size with CMV. Polymerase chain reaction analysis confirmed the presence of a specific CMV DNA sequence in A549 cells of several batches from different sources. Our data strongly suggest that the A549 cell line used in several published reports is infected with CMV and that in the majority of cases the anti-A549 'anti-epithelial' antibodies found in renal transplant patients are anti-CMV antibodies.

Adolescent↗

Circulating soluble adhesion molecules in inflammatory bowel disease.

OBJECTIVE: To determine levels of soluble forms of the cell adhesion molecules (CAM), ICAM-1, E-Selectin and VCAM-1 in relation to prevalence, treatment and disease activity in inflammatory bowel disease. PATIENTS AND METHODS: Plasma was obtained from patients with ulcerative colitis (n = 49), patients with ulcerative colitis who had undergone restorative proctocolectomy (n = 32, eight of whom had a clinical pouchitis), Crohn's disease patients (n = 34) and 24 healthy controls. RESULTS: Plasma soluble ICAM-1 levels [medians (ranges in ng/ml)] were significantly higher in patients with active ulcerative colitis [270 (90-510)], pouchitis [415 (310-670)] and active Crohn's disease [305 (200-630)] than in those with inactive ulcerative colitis [225 (140-425), P = 0.031], non-inflamed ileoanal pouch [260 (140-380), P = 0.0004] and inactive Crohn's disease [245 (90-520), P = 0.045], respectively, and controls. The soluble E-Selectin levels were also significantly higher in patients with active ulcerative colitis [55 (40-140)], pouchitis [90 (45-145)], and active Crohn's disease [78 (30-115)] than in those with inactive ulcerative colitis [45 (20-80, P = 0.003], non-inflamed ileoanal pouch [45 (20-90), P = 0.001] and inactive Crohn's disease [48 (25-90, P = 0.020], respectively, and controls. CONCLUSIONS: The present study suggests that increased levels of soluble ICAM-1 and soluble E-Selectin occur during active inflammatory bowel disease and pouchitis, which may be used as sensitive markers of continuing inflammation.

Adult↗

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↗

Anti-idiotypic activity against anti-myeloperoxidase antibodies in pooled human immunoglobulin.

We investigated the ability of six different pooled human immunoglobulin (PHIG) preparations to inhibit the binding of anti-myeloperoxidase (MPO) antibodies to MPO. All six PHIG preparations inhibited the binding of anti-MPO antibodies from six sera to MPO in a concentration-dependent manner in the concentration range 0.016-10 mg/ml. There was considerable variation in the ability of each PHIG preparation to inhibit the binding of anti-MPO antibody in a given serum. Further differences were seen in the ability of a given PHIG to inhibit anti-MPO binding in different sera. F(ab')2 fragments from two PHIG preparations also inhibited in a concentration-dependent manner anti-MPO binding to MPO in all six sera in the concentration range 0.002-2.65 mg/ml, with a maximum inhibition of 42%. Little inhibition was seen with F(ab')2 of normal human IgG from individual donors (1.8-12.2% at the maximum concentration of 2 mg/ml). F(ab')2 fragments from three anti-MPO containing sera and two affinity-purified anti-MPO antibodies were eluted by affinity chromatography from Sepharose-bound PHIG F(ab')2 and showed anti-MPO antibody activity. We have shown that PHIG and F(ab')2 fragments of PHIG inhibit anti-MPO binding to MPO, and further that F(ab')2 fragments of PHIG bind to F(ab')2 fragments of anti-MPO antibodies. These observations indicate binding between the variable regions of PHIG and the antigen binding site of anti-MPO antibodies, and are consistent with an anti-idiotypic reaction. The variability seen in the inhibitory effect of the different PHIG preparations in anti-MPO-positive sera implies differences in their anti-idiotype content, while the variability of the inhibitory effect of a particular PHIG preparation between different sera suggests heterogeneity in the idiotypic repertoire of anti-MPO antibodies. Such variations in the inhibitory effect of different PHIG preparations on antibody binding may be an important determinant of their therapeutic effect.

Animals↗

Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression and function on cultured human glomerular epithelial cells.

Glomerular epithelial cells are involved in extracapillary inflammation (crescents) but the mechanisms of this extracapillary accumulation of macrophages, epithelial cells and occasional lymphocytes are unknown. Human glomerular parietal epithelial cells express ICAM-1 and VCAM-1 on immunohistological stains of renal biopsies. We studied the expression of these cell adhesion molecules on cultured human glomerular epithelial cells (HGEC), their regulation by pro-inflammatory cytokines, and their role in mediating the adhesion of concanavalin A (Con A)-activated peripheral blood mononuclear cells. Human glomerular epithelial cells in culture constitutively express ICAM-1 and VCAM-1. The expression of ICAM-1 was not significantly altered by tumour necrosis factor-alpha (TNF-alpha) (P = 0.32), IL-1 beta (P = 0.24), interferon-gamma (IFN-gamma) (P = 0.66) or IL-4 (P = 0.85). VCAM-1 expression was increased by all four cytokines, but only significantly so by IL-4 (P = 0.0001). Con A-stimulated, monocyte-depleted peripheral blood lymphocytes bound to human glomerular epithelial cells, median 28.9% (range 14.5-37.9%). This adherence was significantly inhibited by anti-ICAM-1 (P = 0.03) and anti-LFA-1 (P = 0.02), but not by anti-VCAM-1 (P = 0.13) or by antibody to von Willebrand factor (P = NS). The interaction between ICAM-1 on HGEC and LFA-1 on mononuclear cells may be important in the pathogenesis of extracapillary inflammation in glomerulonephritis.

Cell Adhesion↗

Circulating soluble adhesion molecules in systemic vasculitis.

The plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1), E-selectin (sE-selectin), and vascular cell adhesion molecule-1 (sVCAM-1), might reflect endothelial activation and injury and would therefore be useful markers of disease activity in vasculitis. To investigate this we measured the levels of sICAM-1, sE-selectin, and sVCAM-1 by two-site ELISAs in the plasma of patients with (a) active vasculitis (n = 16), (b) vasculitis in remission (n = 15), (c) chronic renal failure (CRF) (n = 10), and (d) normal healthy controls (n = 10). Plasma sICAM-1 levels were significantly higher in patients with active vasculitis, 323 ng/ml (193-607) compared with patients with inactive vasculitis, 199 ng/ml (131-297); P = 0.0006 and healthy controls, 188 ng/ml (138-259); P = 0.0002. Plasma sE-selectin levels were also significantly higher in the patients with active vasculitis, 45 ng/ml (15-65) compared with patients with inactive vasculitis, 25 ng/ml (15-55); P = 0.027 but not when compared with healthy controls, 35 ng/ml (20-55); P = 0.16. There was no difference in plasma sVCAM-1 levels between patients with active vasculitis, OD 0.56 (0.45-0.85) and inactive disease, OD 0.58 (0.47-0.79) (P = 0.12) or with healthy controls OD 0.49 (0.42-0.68) (P = 0.48). There were no significant differences between the plasma levels of any of the soluble adhesion molecules between patients with active vasculitis and patients with chronic failure.(ABSTRACT TRUNCATED AT 250 WORDS)

C-Reactive Protein↗

Knowledge of renal histology alters patient management in over 40% of cases.

There is great debate as to whether the benefit gained from the knowledge of renal histology outweighs the risk to the patient from the biopsy procedure. We conducted a prospective study of 276 native renal biopsies performed on 266 patients from a single centre in 1991 to assess the effect of the knowledge of renal histology on patient management. Biopsies were performed under ultrasound guidance using the Trucut biopsy needle. The indications for biopsy were: non-nephrotic proteinuria alone (25), haematuria and proteinuria (28), nephrotic range proteinuria (28), acute renal failure (31), haematuria alone (36), and chronic renal failure (128). Two hundred and sixty-three biopsies were successful. The mean number of glomeruli obtained was 23, range 0-115. Eight patients developed macroscopic haematuria of which two required blood transfusion. The result of the biopsy altered management in 24/28 (86%) of cases of nephrotic range proteinuria, 22/31 (71%) of cases of acute renal failure, 58/128 (45%) of cases of chronic renal failure, 9/28 (32%) of cases with haematuria and proteinuria, 3/25 (12%) of cases with non-nephrotic proteinuria alone, and 1/36 (3%) of cases with haematuria alone. management was altered in 42% of cases overall. These data suggest that knowledge of renal histology is essential in the management of patients with renal disease.

Adolescent↗

Birmingham Vasculitis Activity Score (BVAS) in systemic necrotizing vasculitis.

The continuing morbidity of patients with vasculitis, despite the improved prognosis with aggressive therapy, underlines the need for accurate disease assessment. We have devised a clinical index of disease activity, and evaluated its use in several forms of necrotizing vasculitis. The weighted score is based on symptoms and signs in nine separate organ systems. Disease features are only scored if they are attributable to active vasculitis. The Birmingham Vasculitis Activity Score (BVAS) was compared with two other published vasculitis activity scores, with the physician's global assessment (PGA), with outcome, and with serological markers of disease activity. In a cross-sectional study of 213 consecutive patients with different forms of vasculitis, all 107 vasculitis patients who were judged completely well on clinical assessment had a BVAS score of 0. Twenty-two patients with active vasculitis prior to treatment had a median score of 7.5 (range 4-30) and 69 with active disease on treatment had a median score of 10 (1-29). Of the 12 who died, median score immediately prior to death was 20.5 (9-30). In a serial prospective study, 30 cases had documented episodes of active disease. During periods of disease activity, the median BVAS values were significantly higher than in remission (15 [range 3-32] vs. 0 [0-2], p < 0.001); the same was true for CRP values (80 [9-361] vs. 13.5 [5-68], p < 0.001). This was not true for erythrocyte sedimentation rate (ESR), haemoglobin (Hb) or von Willebrand factor (VWF).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

Classical versus non-renal Wegener's granulomatosis.

We investigated whether 'limited' or 'non-renal' Wegener's granulomatosis (WG) differs from classical or 'renal' WG. Renal WG is characterized by necrotizing granulomatosis of the upper and or lower respiratory tract, accompanied by systemic vasculitis and focal segmental necrotizing glomerulonephritis. This last feature is absent in non-renal WG. In a prospective follow-up study of all identified cases presenting to a single teaching hospital, we reviewed 22 patients with non-renal WG, and compared their presentation and outcome with that of 28 patients with renal WG. Clinical and laboratory assessment of disease activity, frequency of death, relapse and end-stage renal disease were assessed. The two groups differed in clinical presentation, laboratory features and outcome. The group with non-renal WG had less cutaneous and pulmonary disease; the haemoglobin, white cell count and platelet count tended to be normal. Residual mortality was confined to the renal group. However, the groups shared many features, particularly their requirement for immunosuppressive therapy, since WG causes major tissue destruction regardless of whether it is a localized or widespread process. At the immunopathological level, the two groups appear to be part of a single disease spectrum. Importantly, the non-renal WG group may change the pattern of their disease to involve the kidney. Long-term follow-up of such patients is therefore essential.

Adult↗