David Woodrow

DIFFERENTIAL IN SITU EXPRESSION OF CYTOKINES IN RENAL ALLOGRAFT REJECTION

The expression of the interleukin 6, tumor necrosis factor alpha, and interferon gamma (IFN-gamma) genes was studied in human renal biopsies from individuals without evidence of kidney disease and from patients undergoing acute renal allograft rejection using a method of in situ hybridization capable of detecting 1-5 copies of a specific cellular messenger RNA in individual cells. IL-6, TNF-alpha, and IFN-gamma RNA transcripts were not detected in any of the sections of normal human kidneys. Elevated levels of IL-6 mRNA but not IFN-gamma were, however, detected in the sections of the renal biopsies from six of eight patients exhibiting acute rejection. A uniform level of expression of IL-6 mRNA was observed in all the cells examined, including glomerular cells, tubular epithelia, smooth muscle cells, and vascular endothelia, as well as the interstitial mononuclear infiltrate. Juxtatabular clusters of TNF-alpha mRNA were detected in the absence of IL-6 mRNA in one patient exhibiting acute rejection. Only a small number of grains (1-5 per high-power field) was detected in the urinary space or in the tubular or vascular lumen following hybridization with the IL-6 or TNF-alpha probes. In contrast, in kidney transplant patients with stable renal function no significant labeling was observed with the IL-6, TNF-alpha, or IFN-gamma probes. A similar level of expression of actin mRNA was observed in all the sections of normal and transplanted kidneys studied, suggesting that the overall level of RNA synthesis was similar in both groups. These results suggest that cytokines such as IL-6 play a role in acute allograft rejection.

Muscle fibre characteristics and lactate responses to exercise in chronic fatigue syndrome

OBJECTIVES To examine the proportions of type 1 and type 2 muscle fibres and the degree of muscle fibre atrophy and hypertrophy in patients with chronic fatigue syndrome in relation to lactate responses to exercise, and to determine to what extent any abnormalities found might be due to inactivity. METHODS Quadriceps needle muscle biopsies were obtained from 105 patients with chronic fatigue syndrome and the proportions of type 1 and 2 fibres and fibre atrophy and hypertrophy factors were determined from histochemical preparations, using a semiautomated image analysis system. Forty one randomly selected biopsies were also examined by electron microscopy. Lactate responses to exercise were measured in the subanaerobic threshold exercise test (SATET). RESULTS Inactivity would be expected to result in a shift to type 2 fibre predominance and fibre atrophy, but type 1 predominance (23%) was more common than type 2 predominance (3%), and fibre atrophy was found in only 10.4% of cases. Patients with increased lactate responses to exercise did have significantly fewer type 1 muscle fibres (p<0.043 males, p<0.0003 females), but there was no evidence that this group was less active than the patients with normal lactate responses. No significant ultrastructural abnormalities were found. CONCLUSION Muscle histometry in patients with chronic fatigue syndrome generally did not show the changes expected as a result of inactivity. However, patients with abnormal lactate responses to exercise had a significantly lower proportion of mitochondria rich type 1 muscle fibres.

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.

Skin involvement in Kikuchi's disease : an immunocytochemical and immunofluorescence study

Kikuchis disease (KD) is a benign self-limiting febrile illness usually affecting young women, which is manifested clinically by fever and cervical lymphadenopathy. Skin involvement in KD is very rare and is evident clinically in the form of skin rashes and nodules. We describe one such case of KD in a 33-year-old Bulgarian woman who presented with cervical and axillary lymphadenopathy and who developed a transient facial rash. Biopsy of axillary lymph nodes showed the characteristic features of KD with infiltration of the lymph node paracortex by apoptotic plasmacytoid monocytes. Biopsies of the facial skin showed two features: (1) dermal infiltration by apoptotic plasmacytoid monocytes; (2) on immunofluorescence studies of frozen sections prepared from involved and uninvolved facial skin, deposition of immunoglobulins and complement at the dermoepidermal junction and in the walls of dermal blood vessels. Such immunofluorescence findings in the skin of patients with KD have never been described. These findings suggest the presence of an autoimmune reaction as a component of KD.

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.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 ( V te) 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 V te 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.

An ultrastructural study of the colocalization of biglycan and decorin with AA amyloid fibrils in human renal glomeruli.

An investigation was undertaken on paraformaldehyde-fixed, Lowicryl resin-embedded renal biopsies from patients with AA amyloidosis to study the association of two small chondroitin sulphate/dermatan sulphate proteoglycans, decorin and biglycan, with amyloid fibrils using an ultrastructural immunogold technique. Biglycan was present in glomerular endothelial cells in both normal kidney and in amyloidosis, but little biglycan or decorin was present in the normal mesangial matrix. By contrast, conspicuous amounts of both biglycan and decorin were seen to be associated with amyloid fibrils in the glomerular matrix in cases of renal AA amyloidosis. The results further emphasise the close association between amyloid and extracellular matrix components which are now considered to be an integral part of the amyloid fibrils.

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.

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.

Glomerulonephritis Associated with Permanent Pacemaker Endocarditis

Two patients with permanent transvenous cardiac pacemakers were seen with a history of pyrexia of unknown origin and renal failure. After extensive investigation both were found to have pacemaker endocarditis. A renal biopsy of one patient revealed changes characteristic of glomerulonephritis associated with this condition. Both patients underwent thoracotomy for open removal of their pacemaker and appropriate antibiotic treatment. One patient made a good recovery of renal function. Unfortunately the second patient died. These reports emphasize the need for vigilance for these two uncommon complications and the difficulty in their diagnosis.