Renal allograft rejection: beta-chemokine involvement in the development of tubulitis

BACKGROUND

Tubulitis is a defining feature of renal allograft rejection. Graft dysfunction may result from damage inflicted on tubular epithelial cells by intratubular cytotoxic T lymphocytes. Graft cells are known to produce chemokines during acute rejection, but it is not known whether changes in expression of specific chemokines can influence the composition of the intratubular lymphocyte population. We examined expression of individual chemokines in biopsy sections showing different pathological rejection grades.

METHODS

Sections from Banff-graded transplant biopsies were examined for the presence of beta-chemokines (MCP-1, MIP-1alpha, MIP-1beta, and RANTES) by immunofluorescence and semiquantitative confocal laser scanning microscopy.

RESULTS

Beta-chemokines were expressed predominantly at the basolateral surface of tubular epithelial cells. Expression of MCP-1 and MIP-1beta was significantly higher in sections showing grade 2 rather than grade 1 acute rejection. RANTES and MIP-1alpha showed no significant variation in level of expression between rejection grades.

CONCLUSIONS

Beta-chemokines are expressed by tubular epithelial cells during acute rejection. Consistent expression of RANTES and MIP-1alpha suggests a general role in recruiting T lymphocytes. However, MCP-1 and MIP-1beta may play a more subtle role in recruitment of specific T-cell subsets, such as Th1 cells, during acute cellular rejection.

Focal changes in nerve, muscle and connective tissue in normal and unstable human bladder

OBJECTIVE

To compare and quantify, in a morphological study, the changes that occur in the connective tissue elements (elastin and collagen), muscle fibre diameters and nerve densities between normal, idiopathic and neuropathic bladders.

MATERIALS AND METHODS

Bladder tissue was obtained from 27 patients undergoing cystectomy for carcinoma, from 12 with idiopathic instability and from seven neuropathic patients who were undergoing ileocystoplasty. A combination of histochemical and immunohistochemical techniques were used to detect detrusor muscle, connective tissue and nerve profiles in the bladder tissue.

RESULTS

In both idiopathic and neuropathic bladder tissue the structural changes were highly punctate. From the density of nerve profiles, three areas were defined: (i) apparently unaffected normal fascicles with a high density of nerves, no hypertrophy of the muscle and no infiltration of elastin and collagen. The nerve density in these areas was similar to that in normal bladder tissue. (ii) Fascicles with a low density of nerve profiles, muscle hypertrophy but no connective tissue infiltration. (iii) Areas with few nerve profiles, muscle hypertrophy and extensive elastin and collagen infiltration within the fascicles. The mean (sem) density of nerve profiles in control tissue was 752 (53) nerves/mm2 and in the idiopathic bladders was 905 (91), 81 (20) and 74 (38) nerves/mm2 in the three defined areas, respectively. In the neuropathic tissues the nerve profile densities were 672 (249), 57 (23) and 37 (28) nerves/mm2, respectively. Fibre diameter, elastin and collagen content and nerve density were measured in normal and unstable bladder tissue using these three defined areas. The mean (sem) fibre diameter was 6.81 (0.52) in normal bladder; in idiopathic bladder tissue the fibre diameters in the three areas were 6.72 (0.62), 7.06 (0.62) and 7.34 (1.15) micrometer, respectively, and in neuropathic bladders were 6.75 (0.62), 8.24 (0.62) and 9.35 (0.62) micrometer, respectively. The relative areas of elastin were 0.79 (0.70), 0.56 (0.45) and 18.3 (4.1)% for the control, normal and affected areas of the neuropathic bladders, respectively, and the relative areas of collagen were 3.5 (1.3), 6.15 (3.6) and 15.7 (5. 0)%, respectively. The pattern was similar in idiopathic bladders.

CONCLUSION

These observations suggest that the primary defect in the idiopathic and neuropathic bladders is a loss of nerves accompanied by a hypertrophy of the cells. These changes may continue with further hypertrophy of the cells and an increased production of elastin and collagen within the muscle fascicles.

Beta-chemokine expression and distribution in paraffin-embedded transplant renal biopsy sections: analysis by scanning laser confocal microscopy

Previous immunohistochemical and in situ hybridisation studies have shown that, in tubulitis associated with acute cellular rejection of human renal allografts, intratubular T cells proliferate and are fully activated in situ. In the immunohistochemical study reported here we have attempted to establish some understanding of the involvement of the beta-chemokines RANTES, MCP-1, MIP-1alpha and MIP-1beta in recruiting T cells to the intratubular site. Paraffin-embedded routine biopsy sections were treated for conventional indirect immunofluorescence to detect the selected chemokines. Scanning laser confocal microscopy was used to provide a measure of fluorescence intensity resulting from binding of FITC-labelled secondary antibody. Cells expressing chemokines could be identified and, within the limits of the staining method, it was possible to obtain a semi-quantitative assessment of individual chemokine activity at different points in biopsy sections by constructing a profile of fluorescence intensity. High concentrations of chemokines (especially RANTES, MIP-1beta and/or MIP-1alpha) were localised to the basolateral surface of tubular epithelial cells (TEC). MCP-1 was also consistently present but at a lower level than RANTES except in one case identified as BANFF category 3. There was diffuse distribution of chemokines in the interstitial matrix and low intensity fluorescence outlined some endothelial cells of peritubular venules and interstitial fibroblast-like cells. Our results suggest a mechanism for specific chemotactic recruitment of inflammatory cells by TEC-produced chemokines.

Renal allograft rejection--in situ demonstration of cytotoxic intratubular cells

A nonisotopic in situ hybridization method to detect perforin mRNA was developed in cytospin preparations of IL-2-stimulated normal human lymphocytes and applied to formalin-fixed acutely rejected renal transplant material. Individual cells expressing perforin mRNA were localized in severely damaged tubular areas, and a number of these cells appeared to be located inside the tubular basement membrane in close association with tubular epithelial cells. Immunoperoxidase staining in acetone-fixed cryostat sections of acutely rejected kidney confirmed that a considerable proportion of infiltrating cells was CD8+; many of these were in an intratubular location. In addition, perforin protein was identified in individual cells in similar locations to perforin mRNA-positive cells. Again, some intratubular cells were identified. Our findings illustrate that these cells can be fully activated with definite cytotoxic potential. Previously we have demonstrated that T lymphocytes proliferate within the tubular compartment during tubulitis, a characteristic condition in acute renal allograft rejection, and that there is associated tubular epithelial cell proliferation. In this study we think that we have further clarified the consequences of invasion of tubules by lymphoid cells. Our in situ hybridization method in rapid and convenient and may be applied to archival material.

In situ lymphoproliferation in renal transplant biopsies

A double immunohistochemical labelling procedure in paraffin-embedded renal tissue is reported in which CD3 was targeted as a T cell marker and Ki67 as a marker of cell proliferation. Proliferating and quiescent T cells were unequivocally identified in situ, and their precise location within the kidney was clarified by the use of periodic acid-Schiff counterstaining to outline the basement membranes. Proliferating tubular epithelial cells were also clearly identified. The results showed that T lymphocytes proliferate within the tubular compartment during acute renal allograft rejection. Preliminary evaluation of the method in routine transplant biopsies indicated significant correlations between histologically defined rejection grade and mean intratubular T lymphocytes per tubular cross section and between proliferation of tubular epithelial cells and of intratubular T lymphocytes. The associated tubular epithelial cell proliferation may be a response to local damage.

Anti-glomerular basement membrane glomerulonephritis in the mouse: the role of macrophages

An immunohistochemical study was undertaken on fixed, paraffin-embedded mouse kidney in order to elucidate the role and significance of infiltrating macrophages in a mouse model of anti-glomerular basement membrane glomerulonephritis (anti-GBM GN). Tissue was available representing the full gamut of histological features seen in this model. The mouse macrophage-specific antigen F4/80 was detected in tissue sections of glomerulonephritic kidney and the pattern and extent of staining was compared with normal mouse kidney. In glomerulonephritic kidney, an increase in the number of F4/80-positive cells was evident in close proximity to and surrounding Bowman's capsule of those glomeruli which were severely damaged, with extensive fibrin deposition and well developed cellular crescents. F4/80-positive cells did not feature in the glomerular tuft or in the region of the parietal epithelium of Bowman's capsule even when extensive cellular crescents were present. Breaks in Bowman's capsule were not demonstrated. We conclude that F4/80-positive macrophages are not a major constitutive cell type of developing crescents in this mouse model of anti-GBM GN but, by virtue of their peri-glomerular localization, may be involved in the destructive process, perhaps producing signalling molecules which contribute to the inflammatory reaction.

In vitro bromodeoxyuridine labelling of renal biopsy specimens: correlation between labelling indices and tubular damage

AIMS

To examine the correlation between bromodeoxyuridine (BrdU) labelling indices (LI) and tubular damage in renal biopsy specimens; to evaluate the diagnostic and prognostic potential of measuring cell proliferation in a variety of renal lesions.

METHODS

In vitro BrdU labelling of renal biopsy specimens was undertaken and labelled cells were detected in routinely fixed, paraffin wax embedded sections by immunohistochemistry. The BrdU LI were calculated as percentages for the three types of tubular cells--proximal and distal convoluted tubules and medulla (LI/PCT, LI/DCT, LI/Med)--and a total tubular BrdU LI (LI/Tub) was also calculated for each biopsy specimen. Histological features indicative of tubular damage were also scored and a total tubular damage score obtained for each biopsy specimen.

RESULTS

The one hour labelling process did not affect tissue morphology or impede subsequent diagnosis. Four biopsy specimens were obtained from three renal transplant recipients. Diagnosis of 19 non-transplant biopsy specimens revealed a variety of renal lesions. Total tubular damage scores ranged from 0 to 25 and the LI/Tub ranged from 0 to 3.68% in all 23 biopsy specimens. Analyses of variance showed highly significant correlations between the total tubular damage score and both LI/Tub (p = 0.004) and LI/PCT (p = 0.004); a weaker correlation was found between the total tubular damage score and LI/DCT (p = 0.013).

CONCLUSIONS

A correlation was found between tubular damage and BrdU LI. This was most clearly seen in the proximal tubules. However, as the study was limited to a few examples of specific forms of glomerular or interstitial disease, firm conclusions about the value of BrdU labelling in routine diagnosis and prognosis could not be drawn.

Tissue artefacts caused by sponges

Images

Renal allograft rejection: expression and function of VCAM-1 on tubular epithelial cells

The interaction between vascular cell adhesion molecule-1 (VCAM-1) and very late antigen-4 (VLA-4) is known to play an important role in stabilizing the adhesion of lymphocytes to endothelial cells. Such cellular adhesion is crucial to many immunological processes including lymphocyte-mediated cell lysis. In this study the expression of VCAM-1 on renal tubular epithelial cells is demonstrated on biopsy sections recovered during acute renal allograft rejection. Experiments performed using epithelial cells cultured from renal tubules show that VCAM-1 is up-regulated by addition of the inflammatory cytokines tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). Combination of TNF-alpha and IFN-gamma synergized to induce high levels of VCAM-1 expression. Further experiments demonstrated that the cytokines produced by activated lymphocytes in mixed leucocyte culture also up-regulate expression of VCAM-1. Assays of the adhesion of lymphoid cells to cultured renal epithelial cells showed that cytokine pretreatment of the renal cells enhanced the binding of lymphoid cells. The proportion of bound lymphoid cells was significantly reduced by addition of an antibody capable of blocking the interaction of VCAM-1 with VLA-4. This result indicated that the VCAM-1 induced on renal epithelial cells by inflammatory cytokines is functionally capable of binding VLA-4, thereby enhancing the adhesion of potentially graft-damaging lymphoid cells.

Tissue distribution of amyloid P component as defined by a monoclonal antibody produced by immunization with human glomerular basement membranes

A monoclonal antibody reactive against amyloid P component (NCL-AMP) has been developed following immunization of mice with partially-purified human glomerular basement membranes (GBM) and standard hybridization and cloning techniques. The antibody reactivity was evaluated by enzyme-linked immunosorbent assay (ELISA) and by the indirect immunoperoxidase technique on sections of frozen and fixed human kidney and other tissues. The distribution of amyloid P component in various normal tissues is described and the possible co-localization with the Goodpasture antigen is discussed. In addition, the suitability of the antibody for detection of amyloid deposits in renal amyloidosis is demonstrated and its potential for use in other pathological conditions is considered.

Anti-glomerular basement membrane glomerulonephritis (anti-GBM GN) in the mouse: BrdU-labelling indices and histological damage

In-vivo BrdU incorporation and visualization by immunohistochemistry, previously reported in normal mouse kidney, were applied to a mouse model of anti-GBM GN, induced by immunization with rabbit anti-mouse GBM antiserum, to assess the contribution of capsular cell proliferation in the development of crescents. A significant increase (P = 0.003) in the BrdU-labelling index (LI) for capsular cells was observed, as compared to normal mice (5.76 +/- 1.1 vs 0.70% +/- 0.12%). Elevated LI were also observed for tuft and tubular cells but these increases were not statistically significant. It was concluded that, in this model, capsular cell proliferation is a major contributory factor to the formation of cellular crescents. In addition, other pathological features, indicative of glomerular damage, were assessed semi-quantitatively alongside numbers of labelled capsular cells per glomerulus. It was found that podocyte vacuolation is strongly associated with, and may precede, proliferation, suggesting some common causative factor. Fibrin, when present, was confined within the tuft capillary loops and was only weakly associated with either podocyte vacuolation or capsular cell proliferation. It was concluded that this protein does not play a major role in the initiation of pathological damage. Finally, glomerular lesions were found to be randomly distributed. Thus, the idea of intraglomerular signalling, resulting in 'clustering' of damaged glomeruli, is not supported.

Remnant kidney pathology after five-sixth nephrectomy in rat. II. Electron microscopy study

In Wistar male rats, hypertension was induced by 5/6 nephrectomy (5/6N). Electron microscopy revealed an increase in the number of epithelial cells on the Bowman's capsule during the early stages (4 weeks). After 8 and 12 weeks, frequent adhesion was observed between the glomerular tuft and Bowman's capsule. The abnormal podocytes showed nuclear irregularities and distortions. Characteristic foot process fusion formed cytoplasmic plates. There was a considerable increase in mesangial matrix and cells. No immune deposits or breaks in the glomerular basement membrane were observed. In the endothelial cells, the fenestration disappeared in sclerosed glomeruli. Some capillary loops were obliterated by fibrin, macrophages and foam cells. These findings combined with our previous light microscopy and immunofluorescent observations suggest a non-immunogenic glomerular sclerosis.

Remnant kidney pathology after five-sixth nephrectomy in rat. I. A biochemical and morphological study

In Wistar male rats, hypertension was induced by 5/6 nephrectomy (5/6N). Body weight, blood pressure measurements, morphological and biochemical changes were followed (at four weekly intervals) for 12 weeks after 5/6N. Renal function was assessed by daily total urinary protein (TUP), plasma creatinine concentration [(Cr)p] and creatinine clearance rate. Plasma renin concentration (PRC), aldosterone concentration and erythrocyte content of sodium [Na]E and potassium [K]E were also investigated. Significant increases in systolic blood pressure (SBP), TUP, [(Cr)p] and [Na]E occurred after 4, 8, and 12 weeks of 5/6N. Progressive glomerulosclerosis (GSC), tubular atrophy and interstitial fibrosis were observed. Positive correlations were found between GSC and SBP and TUP. Positive correlations were also found between SBP and [Na]E and [(Cr)P]. PRC was not increased and showed no correlation with SBP. It is concluded that 5/6N produced hypertension associated with a series of morphological and biochemical alterations in kidney structure and function. In this model, mechanisms other than the renin-angiotensin system may be involved.

Tissue artefacts caused by sponges

Artefacts which occur during the processing of small biopsy specimens can cause sufficient tissue distortion to impair interpretation and can be a considerable source of nuisance. Triangular artefacts were noted in renal and liver biopsy specimens which were caused by foam sponges in embedding cassettes. Scanning electron microscopic examination of the sponges showed they comprised a mesh of scimitar-shaped rigid spikes which closely match the artefacts seen in the tissues.

Immunoperoxidase techniques and histology in the diagnosis of rhabdomyolysis related acute renal failure

A case of rhabdomyolysis associated acute renal failure (RM-ARF) occurring as a result of strenuous exercise is presented. Diagnostic renal biopsy was performed. The histological appearances, combined with immunoperoxidase staining for myoglobin, allowed a positive diagnosis of RM-ARF to be made and excluded the possibility of glomerulonephritis. The patient recovered completely after a stormy clinical course.

Three-dimensional reconstruction of human juxtaglomerular apparatus (JGA)

A three-dimensional and morphological study of the human JGA was undertaken to establish a background for understanding the changes in this vital apparatus during various physiological and pathological conditions. Three-dimensional reconstruction was carried out using a computer program "GLOM". Serial sections of normal human kidneys were used after staining with specific human renin antiserum. Three-dimensional reconstruction revealed renin-positive cells in the afferent and efferent arterioles and interlobular arteries away from the JGA area. A close contact was demonstrated between renin-positive cells and the macula densa. The frequency of positively stained JGAs was significantly higher in the superficial glomeruli compared to the deep glomeruli. The high renin content of the superficial glomeruli suggests higher generation of angiotensin, which may contribute to the regulation of the GFR as proposed by other workers. This preliminary study on normal human JGA is to be extended to hypertensive and renal failure patients.

Three-dimensional reconstruction of juxtaglomerular apparatus (JGA) in five-sixth nephrectomized rats

In Wistar male rats, hypertension was induced by five-sixth nephrectomy (5/6N). Body weight, systolic blood pressure (SBP) and plasma renin concentration (PRC) were followed for 12 weeks after 5/6N. Three-dimensional reconstruction and morphometry of the JGA were carried out using a computer program "GLOM". Immunohistochemistry and electron microscopy of the JGA were also investigated. A statistically significant increase in SBP was shown after 5/6N. However, PRC showed no increase and was not correlated with SBP. Renin-containing cells were demonstrated in the afferent and efferent arterioles and the interlobular arteries. Electron microscopy revealed granules of various shapes, sizes and electron densities within the JG cell. The frequency of granulated cells in the efferent arteriole was less than that in the afferent arteriole. The afferent arteriole wall volume of 5/6N rats was significantly increased and positively correlated with SBP. The lack of relationship between PRC and SBP in this model suggests that mechanisms other than the renin-angiotensin system may be involved in the pathogenesis of hypertension.

Interpretation of biopsies of "normal" urothelium in patients with superficial bladder cancer. MRC Superficial Bladder Cancer Sub Group

In the course of a Medical Research Council trial of intravesical chemotherapy, biopsies were taken from apparently normal bladder urothelium near to newly diagnosed superficial bladder cancers in 417 patients. Differences were noted in the rates at which histological features were described in different centres. To gain more information about the reproducibility of the pathological findings, a group of 6 pathologists (5 from the UK and 1 from the USA), all having a special interest in urological pathology, were asked to examine a representative sample of 92 slides. They were then asked to re-examine 30 of them after an interval of at least 6 months. At first examination and at re-examination the slides were assessed using a standard proforma. However, the definitions of the categories were left unspecified for the pathologists to use their own criteria. The 5 UK pathologists then met to establish a consensus view of each slide. The results indicated that: (1) The reporting of non-dysplastic changes varied so much between pathologists as to render it of little value to clinical practice. (2) There were wide variations between different pathologists in the reported incidence of dysplastic change. (3) On a second review the pathologists reproduced their own assessment on only 62% of occasions. (4) Even after discussion between pathologists there was no consensus on the diagnosis of mild as opposed to moderate dysplasia. Consensus was reached on all biopsies which showed either severe dysplasia or carcinoma in situ. (5) In adopting a policy of taking urothelial biopsies, urologists should be aware of the imprecision and lack of reproducibility in the interpretation of such biopsies. (6) Biopsies of cystoscopically normal urothelium may not be a useful guide in defining therapy.

Corrections in counting paired nuclei labelled with bromodeoxyuridine in tissue sections

Bromodeoxyuridine is finding increasing use as an alternative to, or in conjunction with, tritiated thymidine for labelling nuclei in DNA synthesis. Precise identification of labelled nuclei is possible, even when there is considerable overlap between neighbouring nuclei. In the sparsely labelled renal cortex of the normal male mouse, 'flash labelling' with bromodeoxyuridine shows single labelled nuclei at 1 h. At 24, 48 and 72 h after injection of bromodeoxyuridine, some labelled cells are seen to lie adjacent and such labelled pairs are presumed to be the result of cell division. Single labelled nuclei at 24, 48 and 72 h might indicate arrest in DNA synthesis or a prolonged G2 period, but it is important to recognize that a correction must be made for paired labelled nuclei in which one member is out of the plane of section. The factors involved in making such a correction are discussed and a correction table calculated. In the normal male mouse renal cortex, we show that nearly all cells labelled at 1 h had divided by 72 h.

The juxtaglomerular apparatus of the spontaneously hypertensive rat

Spontaneously hypertensive rats (SHR) are used to study the pathogenesis of essential hypertension. This study investigates the role of the renin-angiotensin system (RAS) in the pathogenesis of hypertension in SHRs and the morphometry of the JGA by a three-dimensional computer reconstruction program "GLOM" and electron microscopy. Systolic blood pressure (SBP) (tail cuff method) was higher in SHRs compared to controls (P less than 0.001). Plasma renin concentration (PRC) was lower in SHRs than in controls (P less than 0.001). Reconstruction of the JGA revealed granulated JG cells in the afferent and efferent arterioles and in the vascular tree away from the JGA area. Electron microscopy showed granulated JG cells in the afferent and efferent arterioles. The percentage volume of the granulated JG cells in SHR was significantly higher than in controls (P less than 0.01). A relationship was found between the percentage volume of granulated JG cells and the SBP in SHRs (r = 0.933, P less than 0.05). The wall/lumen perimeter ratio was also significantly higher in the SHRs compared to the controls (P less than 0.05). Low PRC in SHRs has been reported by several workers. The apparent hyperactivity of the JGA may indicate failure of renin release or an abnormal synthesis/secretion rate.

Anti-glomerular basement membrane (GBM) glomerulonephritis in the mouse: development of disease and cell proliferation

In a mouse model of anti-glomerular basement membrane (GBM) glomerulonephritis, associated with the nephrotic syndrome, a wide range of morphological and proliferative responses was seen in the renal corpuscle, at 6 days. The severity of the damage could be assessed by measuring the average daily weight gain between days 0 and 3 (DWG) of the animal. Those animals with a high DWG showed capsular proliferation, whereas animals with a low DWG showed predominantly tuft cell proliferation. Capsular cell birth rate increased with DWG whilst tuft cell birth rate was negatively related. A computer simulation suggests that the results are compatible with the induction of successive but overlapping waves of tuft and capsular cell proliferation.

In vivo bromodeoxyuridine incorporation in normal mouse kidney: immunohistochemical detection and measurement of labelling indices

A method is reported for in vivo bromodeoxyuridine incorporation in mice and its subsequent visualization in kidney by immunohistochemistry. Following formal-sublimate fixation of the kidney, bromodeoxyuridine labelled nuclei were detected in paraffin sections with a monoclonal antibody and visualized by an immunoperoxidase technique. This rapid and unequivocal method was used to measure labelling indices in tubules, glomerular tuft and Bowman's capsule in normal male T70 (Beige) mice, at intervals up to 72h after labelling. Significant differences were found between the labelling indices of these three populations of cells, which appeared to show different cell kinetic behaviour.

Plasma oxalate concentration and secondary oxalosis in patients with chronic renal failure

To examine the association between hyperoxalaemia and secondary oxalosis, measurement of plasma oxalate concentration was combined with a search for tissue deposition of calcium oxalate crystals in patients with chronic renal disease. Two groups of patients were studied. In the first, samples of the inferior epigastric artery were taken from 35 patients at the time of renal transplantation. In the second, sections taken at necropsy from 23 patients with chronic renal failure in whom plasma oxalate had been measured before death were examined. Though plasma oxalate concentrations ranged between 6 and 116 mumol/l (four to 78 times greater than the upper limit of the reference range), no extrarenal deposits of oxalate were found in either study. Renal deposition of oxalate was associated with a plasma oxalate concentration of greater than 20 mumol/l. This study gives no support to the suggestion that hyperoxalaemia of the degree seen in patients with the type of chronic renal failure that is not due to primary hyperoxaluria confers an appreciable risk of extrarenal oxalosis.

Renal vascular disease in diabetes mellitus

Nephropathy remains a major cause of morbidity and mortality in diabetes mellitus and increasing numbers of patients require dialysis maintenance therapy. Diagnostic criteria of diabetic nephropathy are well established, but the relationship between the morphological changes of glomerular basement membrane thickening and increased mesangial volume and functional abnormalities, such as proteinuria and impaired renal function, are still not clearly understood. Tissue studies in patients with micro-albuminuria, as well as increased knowledge of the structure of the glomerular basement membrane, should lead to an understanding of how the diabetic process affects blood vessels throughout the body.

Routine and rapid enzyme linked immunosorbent assays for circulating anti-glomerular basement membrane antibodies

Microtitre plate modifications of the original tube enzyme linked immunosorbent assay (ELISA) of Wheeler and Sussman were used for the routine and rapid assays of anti-glomerular basement membrane antibodies in human sera. In a prospective study of 238 sera from 200 patients, the routine assay (about 24 hours) detected circulating antibodies in seven sera from three patients with active anti-glomerular basement membrane disease. The remaining sera, from patients with a variety of other glomerulonephropathies, were negative by the assay. The rapid assays took less than four hours, and in a retrospective study, detected anti-glomerular basement membrane antibodies in a range of 15 positive sera, with a level of discrimination similar to that observed in the routine assay and with no false positive/negative results.

Acute posterior multifocal placoid pigment epitheliopathy and sarcoidosis

We report on a patient with acute posterior multifocal placoid pigment epitheliopathy and sarcoidosis. A review of the literature suggests that sarcoidosis may occur more commonly in this condition than previously suspected.

Congenital nephrotic syndrome in Sudan: histological and immunological features

We report a 5-month-old Sudanese boy with a probable diagnosis of Congenital Nephrotic Syndrome. Our case had features which are neither typical of the Finnish type nor of other hereditary renal diseases. Histologically, the most striking changes were in the glomerular basement membranes which show patchy thinning, thick segments (with reduplication) and occasional low spikes. Tubules are well preserved, and no foam cells were seen. Electron microscopy showed extensive fusion of foot processes with podocyte microvilli. In parts the glomerular basement membrane shows irregular thickening and splitting, and incorporation of podocyte cytoplasm into the membrane. In other areas there is marked thinning of the basement membrane. Immunological features include a high level of IgA and IgG. To our knowledge such features have not been described before.

HLA-A, B, DR and Bf allotypes in patients with idiopathic membranous nephropathy (IMN)

Fifty-five adult biopsy-proven patients with idiopathic membranous nephropathy were examined for HLA-A, B and DR antigens, and for the Bf allotypes. The phenotype frequencies of HLA-DR3 (52 vs. 23%) and HLA-B8 (46 vs. 24%) showed a significant increase in the IMN patient group compared to those of controls from the same region. The supraphenotype in which the combination of DR3-B8 alleles in Bf SS homozygotes occurred was significantly more common in the patient group than in the controls. A subset of six individuals carrying antigens DR3, B8, and common Bf*S alleles was identified, and the clinical course of those patients was found to be significantly worse compared to the rest of the patients. The present results do not support the existing suggestion that the clinical course of these diseases in Caucasians is determined by antigens B18 and the rare Bf allele (Bf*F1). It seems likely that IMN is not a single disease but a renal lesion that can result from several combinations of genetic predisposition and environmental stimuli.

Peripheral neutrophil inclusions in amiodarone treated patients

In 14 patients receiving chronic amiodarone therapy the appearance of multilamellar inclusion bodies in peripheral blood neutrophils was related to both plasma concentrations of amiodarone and its desethyl metabolite and unwanted effects of the drug. Seven of the patients had well defined inclusion bodies. In this group mean amiodarone and desethylamiodarone concentrations were significantly higher than in the remaining seven patients and all but one had unwanted effects of the drug. Of the seven patients without inclusion bodies only one, with high plasma amiodarone and desethylamiodarone concentrations, had unwanted effects of the drug. It is concluded that the appearance of multilamellar bodies in the blood neutrophils of amiodarone-treated patients may help to distinguish those patients at risk of long-term amiodarone toxicity.

Surface alterations in dialysis roller pump inserts: a scanning electron microscopy study

Scanning electron microscopy has been used in a study of particle spalling from silicone and PVC elastomer inserts of dialysis roller pumps. In an experimental circuit using Isoton II, pump occlusion, pressure, pump revolutions and temperature were monitored. Scanning electron microscopy was performed on inserts exposed to 1-10 h of pumping using Silastic (medical grade) and a Watson-Marlow MHRE pump, with PVC and Pivipol, a polyurethane coated PVC (Bellco) using a Bellco BL705N pump. Changes included longitudinal splits (single and multiple), superficial cracks (random and orientated), deformations of normal surface pattern, holes, craters and detaching particles. There was an increase in these abnormalities with time for all types of pump insert, the changes being most marked for the Silastic/Watson-Marlow pump combination and least prevalent with the PVC/Bellco pump combination.

Particle spallation induced by blood pumps in hemodialysis tubing sets

The repeated flexion and compression of pump segments by the rollers of peristaltic pumps results in cracking and abrasion of the inner surfaces of the pump segment, leading to shedding of particles into the extracorporeal circuit. A series of studies to assess the rate of particle release from silicone rubber, polyvinyl chloride (PVC), and Pivipol, a coextruded polyurethane-coated PVC tubing, when these materials were used with blood pumps of the type found in hemodialysis units, was undertaken. The studies show that with all tubing/pump combinations there is an overall increase in the total number of particles released, but an analysis of the particle size distribution indicates that the majority of the particles are less than 16 micron in diameter. The rate of increase may be reduced, however, by decreasing the occlusion pressure.

Amiodarone pulmonary toxicity: clinical and subclinical features

In a prospective study of lung function of 34 patients taking amiodarone, 24 showed no functional changes but 10 developed a sustained fall in CO transfer factor (TLCO) exceeding 15 per cent. These patients had on average received a higher dose of drug in the first three months of treatment. Seven showed no clinical or radiographic changes and TLCO improved with reduction in drug dose. The other three patients developed florid clinical and radiographic features of amiodarone pulmonary toxicity. All three had impaired TLCO before receiving amiodarone. During the course of the prospective study amiodarone pulmonary toxicity was diagnosed in four other patients. Lung tissue was examined in five of the seven patients with clinical toxicity and showed alveolar wall thickening, exudation and interstitial and intra-alveolar fibrosis with prominent 'foamy' macrophages. Electron microscopy of macrophages showed numerous lysosomal multilamellar bodies, which were demonstrated by energy dispersive X-ray analysis to contain iodine, a constituent of the amiodarone molecule. Two of the patients with clinical toxicity died of respiratory failure; the other five showed gradual improvement on withdrawal of the drug and treatment with corticosteroids. Subsequent withdrawal of steroids was associated with clinical and/or functional deterioration in five patients. A separate autopsy study of the lungs of eight patients dying during treatment with amiodarone, but without clinically-recognised toxicity, showed that an alveolitis had been present in two and prominent 'foamy' macrophages were seen in the lungs of six patients. We conclude that clinical and subclinical effects of amiodarone on the lung are common. The clinical syndrome may be easily misdiagnosed as pulmonary oedema. Subclinical changes in lung function are usually reversible, but whether they herald clinical toxicity if treatment is continued without modification is not established. The presence of 'foamy' macrophages may simply reflect exposure to the drug rather than clinically-important toxicity.

Amiodarone and its desethyl metabolite: tissue distribution and morphologic changes during long-term therapy

The pharmacokinetic characteristics of amiodarone suggest extensive tissue deposition. We confirmed this by measuring tissue concentrations of the drug and of its major metabolite, desethylamiodarone, in human tissues. These were obtained at autopsy (n = 9), surgery (n = 7), or biopsy (n = 2) from 18 patients who had been treated with amiodarone for varying periods of time. High concentrations of amiodarone were found in fat (316 mg/kg wet weight in autopsy specimens, 344 mg/kg wet weight in biopsy specimens). Amiodarone and desethylamiodarone concentrations (mg/kg wet weight, autopsy samples) were also high in liver (391 and 2354), lung (198 and 952), adrenal gland (137 and 437), testis (89 and 470), and lymph node (83 and 316). We also found high concentrations of amiodarone (306 mg/kg wet weight) and desethylamiodarone (943 mg/kg wet weight) in abnormally pigmented ("blue") skin from patients with amiodarone-induced skin pigmentation. These values were 10-fold higher than those in unpigmented skin from the same patients. These high concentrations were associated with lysosomal inclusion bodies in dermal macrophages in the pigmented skin. The inclusion bodies were intrinsically electron dense and were shown to contain iodine by energy dispersive x-ray microanalysis. Lysosomal inclusion bodies shown by electron microscopy to be multilamellar were seen in other tissues. These tissues included terminal nerve fibers in pigmented skin, pulmonary macrophages, blood neutrophils, and hepatocytes and Kupffer cells. These characteristic ultrastructural findings occur in both genetic lipidoses and lipidoses induced by other drugs, e.g., perhexiline. We conclude that during therapy with amiodarone, widespread deposition of amiodarone and desethylamiodarone occurs. This leads to ultrastructural changes typical of a lipidosis. These changes are seen clearly in tissues associated with the unwanted effects of amiodarone, e.g., skin, liver and lung.

Cell proliferation within Bowman's capsule in mice

Crescentic glomerulonephritis in man, irrespective of aetiology, indicates severe glomerular damage and carries a poor prognosis. The importance of the presence of macrophages in the development of glomerular crescents is well established, but the contribution of cellular proliferation in both macrophages and epithelial cells has received little attention. The purpose of this investigation was to develop a model of crescentic glomerulonephritis in mice, which will be suitable for cell kinetic studies. Preliminary studies are described, involving immunization with rabbit anti-mouse glomerular basement membrane (GBM) antiserum after pre-immunization with rabbit immunoglobulin G, both with and without treatment with a fibrinolytic inhibitor, Cyklokapron. Extensive glomerular damage, with crescent formation, was induced with four daily intravenous injections of rabbit anti-mouse GBM antiserum, after pre-immunization with rabbit IgG. The effect was shown to be dose dependent and was seen within 3 days of the last injection. Linear deposits of rabbit IgG were detected in all glomeruli by immunofluorescence and both linear and granular deposits of mouse IgG were also found. There was a significant increase in glomerular size and in the numbers of cells in Bowman's capsule (P less than 0.01), and increases in mitotic indices to 0.8 per cent were seen by day 13.

Urographic findings in adults with chronic pyelonephritis

The radiological findings in a cohort of 138 adults with chronic pyelonephritis are presented and the following conclusions made. Scarring is commoner in the right kidney than the left and is found in the upper, middle and lower poles with decreasing frequency from above down. Agreement between observers in the grading of scarring in urograms taken without standardisation or routine tomography, is sufficiently high to justify the continued use of the intravenous urogram as a screening test but is not high enough to detect any progression of scars in the group over a 6.5-year period. Repetition of urograms seldom reveals the development of calculi or other new abnormalities and is not justified as a clinical routine. The combination of extensive bilateral renal scarring and proteinuria is associated with the worst renal function.

Idiopathic hypergammaglobulinaemia associated with nephrogenic diabetes insipidus and distal renal tubular acidosis

Renal tubular dysfunction may be recognized in patients suffering from urinary light chain disease or non-myelomatous hypergammaglobulinaemia. We report a patient who has the combination of distal renal tubular acidosis and nephrogenic diabetes insipidus in association with hypergammaglobulinaemia due solely to increased IgG. We postulate that the abnormalities of distal nephron function resulted from cell-mediated immune damage.

Haematuria in rheumatoid arthritis: an association with mesangial glomerulonephritis

Twenty-four patients with rheumatoid arthritis and isolated haematuria were investigated for the cause of their haematuria. In 3 patients local urological disorders were identified, including a pelvicaliceal carcinoma. Renal biopsies were performed on the remaining 21 patients, and the most common abnormality found was a mild mesangial glomerulonephritis (71%). Immunofluorescence and electron microscopy in these patients usually gave normal results. The lesions occurred independently of gold or D-penicillamine therapy and were not associated with impairment of glomerular function.

Nephrotic syndrome and renal impairment associated with fenclofenac

We report a case of nephrotic syndrome and renal impairment following treatment with fenclofenac. Biopsy showed an interstitial nephritis with minor glomerular changes. Resolution occurred on withdrawal of the drug and treatment with prednisolone.

Isolated C3 deposition in patients without systemic disease

Deposition of C3 without immunoglobulins ("isolated C3") was found in 9.8% of 540 renal biopsies performed between 1976 and 1982. Thirty-two of these samples were from patients with systemic diseases (16), well defined forms of glomerulonephritis (9), other renal diseases (4) or renal allografts (4). The remaining 22 patients are described. Five had nephrotic syndrome, three of them with minimal changes on light microscopy and good response to corticosteroids. We were left with a group of 17 patients who presented with gross (4) or microscopic (12) hematuria or asymptomatic proteinuria (1) whose biopsies showed mesangial proliferation or/and hyperplasia and who followed a benign course over the mean 3 years of follow-up, with the exception of one whose renal function is declining. This clinicopathological picture is similar to that described in two previous publications suggesting that "Isolated C3 mesangial proliferative nephritis" is a recognizable sub-group within the spectrum of glomerulonephritis.