Upregulation of H+-ATPase in the distal nephron during potassium depletion: structural and functional evidence.

In the present study, we have investigated the effects of dietary potassium depletion on the activity and distribution of the H+-ATPase in the distal nephron of the Sprague-Dawley rat. H+-ATPase activity was assessed from the change in transepithelial potential difference (Vte) in response to bafilomycin A1 during perfusion of the late distal tubule in vivo, with solutions containing inhibitors of known ion channels. Bafilomycin A1 caused a negative deflection in Vte in control animals, an effect that was significantly enhanced during potassium depletion (P < 0.01). The distribution of H+-ATPase within the population of intercalated cells was assessed using a specific monoclonal antibody (E11). Hypokalemia was associated with a highly significant redistribution of the staining pattern (P < 0. 001), with an increase in the percentage of cells displaying immunoreactivity in the apical membrane. These results indicate that dietary potassium depletion increases electrogenic H+-ATPase activity in the rat distal tubule; this may be associated with increased insertion of pumps into the apical membrane.

Scleredema diabeticorum of Buschke confined to the thighs.

We describe a patient with insulin-dependent diabetes without vascular complications in whom scleredema was confined to the thighs. Electron microscopy demonstrated heterogeneity in both the size and density of the collagen fibrils and the presence of filamentous material between them.

Testosterone deficiency myopathy.

Testosterone is recognized to have a positive effect on nitrogen balance and muscle development in hypogonadal men, but significantly myopathy secondary to testosterone deficiency has been reported only rarely. We describe a patient who presented with a myopathy associated with testosterone deficiency, and who demonstrated a significant functional and myometric response to treatment.

Myopathy in acquired partial lipodystrophy.

We describe two women with acquired partial lipodystrophy, one with significant myopathic symptoms and signs. Muscle biopsy of deltoid and quadriceps was performed in each case. The light microscopy findings were of type 1 and type 2 fibre hypertrophy, with an increase in intracytoplasmic fat in both cases. Electron microscopy showed normal fibres, with accumulations of electron-lucent fat droplets between the myofibrils. The cause of the lipodystrophies is uncertain, but myopathy may be a feature, and muscle biopsy studies may help in further defining the syndrome.

Myopathy in HIV infection: the role of zidovudine and the significance of tubuloreticular inclusions.

Muscle biopsies were obtained from 33 consecutive HIV-infected patients with symptoms suggestive of muscle disorder. Twenty-three patients had clinical evidence of myopathy; 18 of these had been taking zidovudine (AZT) for between 8 and 28 months, and were found to have a multifocal necrotizing myopathy with little or no inflammation. However, the remaining five clinically myopathic patients, who had never received AZT or had stopped treatment at least 5 months earlier, had either a necrotizing myopathy which appeared indistinguishable for that seen in patients taking the drug, or an inflammatory myopathy. The 10 clinically non-myopathic patients showed no significant histological abnormalities. Tubuloreticular inclusions (TRI), in capillary endothelial cells, were found in all clinically myopathic cases but were not seen in five out of ten clinically non-myopathic cases. We suggest that AZT causes a myopathy only when an underlying HIV-related inflammatory myopathy is present. The drug appears to substantially reduce the inflammatory reaction in the muscle, but this may recur when the drug is stopped. The appearance of TRI may be the first manifestation of HIV activity in muscle.

Interpretation of duplex Doppler ultrasound in renal transplants in the early postoperative period.

A prospective study of duplex Doppler ultrasound in 29 renal transplants was undertaken to determine how to interpret Doppler findings in the immediate postoperative period. The study included intraoperative pulsed Doppler recordings from grafts immediately following release of vessel clamps. Subsequent follow-up studies were performed in the immediate postoperative period. Intraoperative Doppler appearances in the group as a whole were normal; there was a significant deterioration in Doppler appearances in the first 24-48 h of the postoperative period. In the absence of rejection subsequent Doppler appearances returned to normal. An abnormal Doppler appearance immediately following transplantation should be an expected result. If the Doppler fails to improve, or deteriorates having started to improve, rejection should be strongly suspected.

Hydronephrosis: prevention by restoration of urinary concentrating ability using desamino-8D-arginine vasopressin (DDAVP) in Brattleboro rats.

Male Brattleboro rats with hereditary diabetes insipidus (BDI) were lifetime-treated with the vasopressin V2 receptor agonist desamino-8D-arginine vasopressin (DDAVP), given daily in the drinking fluid. The DDAVP-treated adult male BDI rats drank 34 +/- 6 ml/24 h (mean +/- s.e.m.) and excreted urine volumes of 22 +/- 5 ml/24 h compared with their age-matched untreated controls of 142 +/- 12 and 115 +/- 7 ml/24 h respectively. There was no significant difference between the mean body weights of chronically DDAVP-treated BDI rats (198 +/- 9 g) and untreated animals (207 +/- 9 g). Morphometry of sections of kidney confirmed extensive hydronephrosis in the right kidneys of the control untreated Brattleboro rats only. This was quantified as the area of pelvis expressed as a percentage of total cross-sectional area of kidney (17 +/- 3 compared with 5 +/- 1% in the chronically DDAVP-treated rats; P less than 0.002). Medium-term treatment of adult BDI rats with DDAVP reduced daily fluid output towards normal rat values but hydronephrosis was still present. These observations indicate that the restoration of fluid balance in adult BDI rats by treatment from conception with DDAVP may be an important factor in preventing the development of hydronephrosis in these animals.

Dialysis arthropathy: a clinical, biochemical, radiological and histological study of 36 patients.

Out of a population of 97 haemodialysis patients, 36 patients with dialysis arthropathy were identified. Dialysis arthropathy is a chronic symmetrical polyarthritis which affected 97 per cent of the patients who had been undergoing cuprophane haemodialysis for more than 10 years. It commonly affected the shoulders, hips, hands, knees and wrists, worsening with time and extending to other joints. Fifty-eight per cent of the patients complained of morning stiffness and 47 per cent complained of exacerbation of shoulder pain during or after haemodialysis. Half of the patients also suffered from carpal tunnel syndrome, which recurred and was associated with a long-lasting disability. The most common radiological abnormality was periarticular bone cysts, followed by articular erosions and a destructive spondyloarthropathy, but clinical symptoms were more common than radiological signs. Patients with dialysis arthropathy had a higher C-reactive protein level than patients without arthropathy (18.6 mg/l versus 11.4 mg/l), indicative of an inflammatory process. Some of the clinical manifestations of the disease correlated with levels of C-reactive protein and ferritin. Serum ferritin levels correlated strongly with the units of blood transfused in the past five years (RS = 0.83), and the logarithm of ferritin level correlated weakly with C-reactive protein (r = 0.32). Haemarthroses were documented in 19 per cent of patients. Mean serum beta 2-microglobulin was elevated in the patients with (57.3 mg/l) and without arthropathy (50.7 mg/l), and there was no difference in the parathormone or aluminium levels between these groups. Articular tissue was obtained in 25 patients; beta 2-microglobulin amyloid was present in 24. Larger deposits were present in the capsular tissue, and these appeared to replace collagen bundles in eight cases. Amyloid deposits replaced the lining layer in six cases. It is likely therefore that amyloid disrupts normal joint function by replacing normal joint tissue. Mild chronic synovitis with haemosiderin deposition were found in approximately 60 per cent of cases. These findings suggest that amyloid derived from beta 2-microglobulin has a primary role in the pathogenesis of dialysis arthropathy, but there was also evidence of inflammatory processes. It is suggested that iron overload or haemarthroses might contribute to the inflammation, but other factors, such as dialysis-related bioincompatibility reactions, may also have a role.

SLE nephritis: an ultrastructural immunogold study to evaluate the relationship between immune complexes and the basement membrane components type IV collagen, fibronectin and heparan sulphate proteoglycans.

The nature of immune complexes and their relationship to the normal glomerular basement membrane (GBM) components type IV collagen, fibronectin, and heparan sulphate proteoglycans (HSPG) have been examined in the glomeruli of 7 cases of systemic lupus erythematosus (SLE) glomerulonephritis using an ultrastructural immunogold technique. In paraformaldehyde-fixed, Lowicryl resin-embedded tissue, the electron-dense deposits contained IgG, IgM, IgA, and C3 whether they were subepithelial, intramembranous, subendothelial, or mesangial and there was no particular relationship between the class of immunoglobulin and site of immune complex localization within the glomerulus. The normal GBM components type IV collagen, fibronectin, and HSPG were found within all the glomeruli, but did not have the same distribution. Type IV collagen and fibronectin were found predominantly on the inner aspect of the GBM and diffusely throughout the more central regions of the mesangial matrix. By contrast the HSPG was seen mainly on the outer aspect of the GBM and at the periphery of the mesangial matrix. In none of the cases were GBM antigens localized within the electron-dense deposits, results which suggest that autoantibodies to these GBM components may not play a role in the development of the glomerulonephritis.

Ultrastructural immunogold studies of heparan sulphate proteoglycan in normal human glomeruli and glomerulonephritis.

The distribution of heparan sulphate proteoglycans (HSPG) has been investigated in normal human glomeruli, membranous glomerulonephritis, mesangial IgA disease, and anti-glomerular basement membrane disease. HSPG was localized using anti-bovine HSPG antibody and 10 nm gold-labelled secondary antibody on paraformaldehyde-fixed, Lowicryl K4M resin-embedded kidneys. HSPG was present in all glomeruli and there was a zonation of its distribution in that it was predominantly on the epithelial aspect of the glomerular basement membrane (GBM) and mesangium with little in the central regions of the mesangial matrix. In the cases of immune complex glomerulonephritis, no HSPG was found in the electron-dense deposits. These findings contrast with our previous studies using the same technique in which type IV collagen and fibronectin were found predominantly on the endothelial aspect of the GBM.

Macroglossia and amyloidoma of the buttock: evidence of systemic involvement in dialysis amyloid.

A 48-year-old male on cuprophane haemodialysis for 18 years, with a history of dialysis arthropathy and recurrent carpal tunnel syndrome developed macroglossia and bilateral buttock tumoral masses. The tongue and buttock masses were biopsied. Histology of both biopsies showed amyloid deposits of the beta 2-microglobulin (B2M) variety. Amyloidomas in the gluteal region and macroglossia have not been previously described in amyloid derived from B2M. These findings suggest that systemic B2M amyloidosis can have a similar tissue distribution to AL amyloidosis. This case also stresses the importance of inspection of the tongue, and palpation of the gluteal region for masses, in the assessment of patients with dialysis arthropathy.

Second antibody for improvement of antibody imaging: liposome-entrapped and free preparations in animal and human studies.

When anti-tumour antibodies are given systematically for tumour imaging or therapy, second antibody directed against the first (anti-tumour) antibody can be used to accelerate clearance of first antibody, thus improving discrimination between tumour and normal tissues. Liposome-entrapped, and free second antibodies (LESA and FSA, respectively) have been compared in an animal tumour model system and in patients with cancer. Nude mice bearing xenografts of human colon carcinoma were given goat antibody to carcino-embryonic antigen (CEA) as first antibody and horse anti-goat second antibody. Patients with gastrointestinal carcinomas received i.v. 131I-labelled goat anti-CEA or mouse monoclonal 17-1A first antibody and unlabelled horse angi-goat or rabbit anti-mouse second antibody, respectively. Antibody distribution was studied by serial gamma camera imaging. The effectiveness of LESA and FSA depended on dose. Tumour-to-blood ratios were increased up to eight-fold by either method in animals. Tumour imaging was enhanced among 15 patients with gastrointestinal cancer and tumour was correctly identified at five sites where it was not seen by a background subtraction method. No significant toxicity occurred in patients nor in rabbits studied for evidence of immune complex mediated disease. LESA and FSA appear to be equally effective.

Dialysis-associated amyloid: systemic or local?

Dialysis-associated amyloidosis has been classified as one of the local amyloidoses. To test this, we examined post-mortem tissue from 14 long-term haemodialysis patients, ten with dialysis arthropathy and four without arthropathy. Tissue was obtained from the shoulder, knee, or hip joints and the following organs: brain, kidney, liver, heart, lung, spleen, and rectum. Congo-red stain was used to identify amyloid deposits and these were characterised further using an indirect immunoperoxidase technique with antibodies to beta 2-M, prealbumin, serum amyloid A protein, and kappa and lambda light chains. All patients with arthropathy had large deposits of beta 2-M amyloid in the articular tissues. In contrast to this, systemic amyloid deposits were only found in four patients and were small and mainly confined to vessel walls. The four patients without joint symptoms had no evidence of systemic or articular amyloidosis. In addition, subcutaneous fat aspirations were carried out in 13 patients with dialysis arthropathy and 12 without arthropathy. Amyloid deposits were only found in two patients with arthropathy. Our results show that dialysis-associated amyloidosis has a predilection for deposition in articular tissues, and that systemic deposits are infrequent, small, and mainly confined to vessel walls. The discrepancy between our post-mortem series and case reports describing large systemic deposits may be due to differences in patient susceptibility.

Immunoelectron microscopic studies of immune complex deposits and basement membrane components in IgA nephropathy.

The relationship between the immune complex deposits of mesangial IgA nephropathy and the basement membrane components, type IV collagen and fibronectin, has been investigated by an indirect immunogold technique in four cases of mesangial IgA disease. Using paraformaldehyde-fixed, Lowicryl K4M resin-embedded kidney, IgA, IgM and C3 were localized in the mesangial electron-dense deposits with 10 and 20 nm gold-labelled secondary antibodies. In the same glomeruli, type IV collagen and fibronectin were rarely present within the electron-dense deposits, although both were distributed throughout the remainder of the mesangial matrix with the exception of the subepithelial regions. These two components were also present within the glomerular basement membrane and localized mainly on the endothelial aspect. A similar distribution of the basement membrane components was seen in a control kidney processed in the same way. This technique gives reproducible results and has demonstrated for the first time the relationship between the mesangial immune complex deposits of mesangial IgA nephropathy and the basement membrane components of the matrix in which they are found.

Morphometric comparison of synovium from patients with osteoarthritis and rheumatoid arthritis.

Synovium was collected from 15 patients who were undergoing joint surgery. Two groups were defined by clinical diagnosis: patients with primary osteoarthritis (n = 4); and those with rheumatoid arthritis (n = 11). The synovium was studied using histological and morphometric techniques. In agreement with previous studies, no histological features specific for either diagnosis were found. A previously validated morphometric method was used to estimate the cellular density of randomly picked fields within defined areas of synovium. The mean nuclear density of cellularity of comparable areas of synovium was significantly different between these two disease states, but the mean nuclear density between individual representative samples within each clinical group was homogeneous. The morphometric analysis of lymphocyte subsets showed that within the upper synovial region and cellular aggregates in osteoarthritis, the distribution of T cells expressing the CD4 and CD8 antigen was the same. In rheumatoid arthritis CD8 cells predominated in the upper synovial region and CD4 cells in the cellular aggregates. Plasma cells were rarely found in osteoarthritic synovia, but were common in rheumatoid arthritis, with IgG-producing plasma cells predominating. Morphometric studies of representative synovial samples may help to improve histological diagnosis and our understanding of pathological mechanisms.

Representative sample of rheumatoid synovium: a morphometric study.

The synovium from 11 patients with rheumatoid arthritis, who were undergoing joint surgery, was assessed using histological and morphometric techniques. Histological examination confirmed previous reports that the intensity of the cellular reaction varied throughout the synovium, and the morphometric method reflected this variability sensitively. The method was shown to be reproducible and allowed areas of similar cellular density to be defined. From these defined areas a total of 2.5 mm2 of synovium equivalent to 12 fields at x250 required analysis to reflect the variation in the cellular reaction. It would be feasible to collect this amount of material using an arthroscope.

The arthropathy of cystic fibrosis.

Musculoskeletal symptoms are frequent in cystic fibrosis (CF). Here the clinical features of 29 patients with CF who had significant arthropathy are described. Twelve had episodic arthritis (EA) characterised by repeated short attacks of severe, incapacitating polyarthritis, which in seven was associated with fever and erythema nodosum. Ten patients had hypertrophic pulmonary osteoarthropathy (HPOA). The onset of symptoms in the group with HPOA was usually later (mean age 20 years v 16 years for EA) and was associated with significantly worse lung function than in patients with CF, either without arthropathy or with EA. Seven patients had arthropathies which could not be classified as EA or HPOA.