Emphysematous urinoma in a renal transplant patient.

Urinary infection is a common complication after kidney transplantation. In some instances, especially with Escherichia coli infections, there is formation and collection of gas in the parenchyma and collecting system of the kidney, giving rise to the condition of emphysematous pyelonephritis. Such a process could occur in collections of urine (urinoma) secondary to ureteric leak in the transplant kidney. This process has not been described so far. In this report, we describe the first case of an infected urinoma with an interesting radiologic finding, a so-called emphysematous urinoma.

Human granulocytic ehrlichiosis presenting with acute renal failure and mimicking thrombotic thrombocytopenic purpura. A case report and review.

We present the case of an elderly female patient presenting with recurrent acute renal failure, fever, altered mental status, abdominal pain, thrombocytopenia and a small number of fragmented red cells on peripheral smear mimicking recurrent thrombotic thrombocytopenic purpura (TTP). Eventually, however, she was diagnosed to have human granulocytic ehrlichiosis (HGE), and after treatment for HGE her clinical and laboratory abnormalities resolved. Ehrlichiosis mimicking TTP, diagnosed at postmortem examination, has been described in a single prior case. As illustrated in this case, there are potential difficulties in diagnosing HGE after plasma exchange, blood transfusion and immunosuppressive therapy. Ehrlichiosis, a potentially curable disease, should be considered in the differential diagnosis of thrombotic microangiopathic disorders.

Staphylococcus lugdunensis pulmonary valve endocarditis in a patient on chronic hemodialysis.

We describe a case of Staphylococcus lugdunensis pulmonary valve endocarditis in a 65-year-old woman on chronic hemodialysis and provide a review of previously reported cases. The patient presented with fever and altered mental status, but had no other localizing symptoms or signs; coagulase-negative staphylococcus (subsequently identified as S. lugdunensis) was isolated from two sets of blood cultures. Transthoracic and transesophageal echocardiograms showed a large (2.3 x 3.1 cm) vegetation on the pulmonary valve with moderate valvular insufficiency. The patient was treated with 6 weeks of antibiotic therapy and is stable 4 months following the completion of therapy; no surgical intervention was performed. Of the 28 previously reported cases of S. lugdunensis endocarditis, only 1 had previously survived with medical therapy alone. This is the 3rd case report of S. lugdunensis endocarditis in a patient on hemodialysis; the presumed portal of entry in this and previously reported cases was the vascular access device. Endocarditis due to this organism is characterized by a high mortality, rapid tissue destruction, and a predilection for native valves. Because the clinical outcome is much more favorable with valvular replacement, speciation of the organism assumes great importance in defining the therapeutic approach.

Renal cell cytokine production stimulates HIV-1 expression in chronically HIV-1-infected monocytes.

Renal infiltration of human immunodeficiency virus type 1 (HIV-1)-infected monocytes might play an important role in the development of HIV-associated nephropathy (HIVAN). In the present study, we investigated the effects of cytokines produced by cultured human mesangial cells (HMC) and proximal tubular epithelial cells (PTEC) on HIV-1 expression in chronically HIV-1-infected promonocytes (U1 cells). Human mesangial cells constitutively secreted interleukin-6 (IL-6) but not tumor necrosis factor-alpha (TNF-alpha) into the culture medium, whereas PTEC constitutively secreted both IL-6 and TNF-alpha. Coculture of U1 cells with HMC or PTEC for 72 hours markedly stimulated HIV-1 expression, with the p24 antigen concentration in the coculture supernatants ranging from approximately 200 to 1850 pg/ml. The presence of anti-IL-6 antibody in the coculture medium nearly completely blocked HIV-1 expression in the HMC/U1 cell cocultures (P < 0.05). Anti-IL-6 antibody and anti-TNF-alpha antibody blocked HIV-1 expression in the PTEC/U1 cell cocultures by 40% and 53%, respectively (P < 0.05). Moreover, the combination of anti-IL-6 and anti-TNF-alpha antibodies additively reduced coculture HIV-1 expression by 87% (P < 0.05). We conclude that renal cell production of IL-6 and TNF-alpha might provide a potent stimulus for HIV-1 expression in HIV-1-infected monocytes that infiltrate the kidney, and that this may play an important role in the pathogenesis of HIVAN.

Effects of unilateral or bilateral release of bilateral ureteral obstruction on renal function in rat.

Renal function was examined after unilateral release, bilateral release or unilateral release and contralateral nephrectomy in three groups of rats following 24 h of bilateral ureteral obstruction (BUO). Excretion of water, sodium and urea was significantly greater in rats with unilateral release of BUO than in a single kidney of rats with bilateral release of BUO, in spite of similar levels of glomerular filtration rate (GFR) and effective renal plasma flow. Rats with unilateral release of obstruction and contralateral nephrectomy had a significantly lower GFR than the other two groups. These rats also responded with greater increases in fractional sodium and water excretion to the administration of exogenous atrial peptide. The results demonstrate a marked compensatory increase in sodium and water excretion in rats with unilateral release of the obstruction which serves to maintain homeostasis of fluid and salt. They also suggest a possible influence of the continuously obstructed kidney on the function of the postreleased kidney. The results also provide experimental support for a greater recovery of renal excretory function after bilateral release of obstruction.

Effects of probucol in renal function and structure in rats with subtotal kidney ablation.

Probucol is a bisphenolic compound that lowers serum cholesterol and also has potent antioxidant properties. The present studies examined the effects of probucol administration on renal function and structure in a rat model of subtotal renal ablation. After subtotal nephrectomy, rats were fed an isocaloric rat chow diet containing 22.8% protein with or without the addition of 1% probucol. After 4 weeks, clearance studies were performed for determination of glomerular filtration rate (inulin clearance) and effective renal plasma flow (paraaminohippurate clearance). After completion of clearance studies and measurements of arterial blood pressure, the animals were exsanguinated and renal tissue was obtained for histologic evaluation. There were no differences in body weight, hematocrit, and blood pressure between the two groups of rats 4 weeks after subtotal nephrectomy. Rats with a remnant kidney given probucol had a significantly lower serum cholesterol level (47.4 +/- 5.3 mg/dl vs 87.2 +/- 10.4 mg/dl) and urea nitrogen level (40.7 +/- 3.2 mg/dl vs 63.6 +/- 8.1 mg/dl) than the control group. Rats given probucol also had significantly greater values for inulin clearance and clearance of paraaminohippurate and significantly less proteinuria than control rats. Also, rats with a remnant kidney given probucol had a significantly greater number of normal glomeruli (6.2% +/- 2.1% vs 1.1% +/- 0.9%) and a lesser number of severely affected glomeruli, grades III and IV (26.0% +/- 5.9% vs 50.9% +/- 9.1%) than rats with a remnant kidney not given probucol. Tubulointerstitial changes also were significantly less in rats with a remnant kidney given probucol.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma oxalate in patients with chronic renal failure receiving continuous ambulatory peritoneal dialysis or hemodialysis.

Plasma oxalate was measured in 20 patients receiving continuous ambulatory peritoneal dialysis (CAPD) and 20 patients receiving hemodialysis (HD). All patients had levels well above the reference range of less than 2.0 to 5.0 mumol/L (less than 0.18 to 0.44 mg/L), the medians being 34 mumol/L (2.99 mg/L) and 42 mumol/L (3.70 mg/L) for the two groups, respectively. Plasma oxalate did not differ significantly in the two groups. Plasma oxalate was not influenced by the number of months patients had received dialysis treatment, but a significant correlation was found between oxalate and creatinine in the 40 patients studied (P less than 0.02, r = 0.38). Predialysis oxalate levels were reduced by approximately 60% following HD, but returned to 80% of the predialysis levels within 24 hours and 95% within 48 hours. Oxalate levels did not differ significantly in samples taken before, during, and after exchanges of CAPD fluid. That the patients treated with CAPD did not have higher oxalate levels than the HD group suggests that the continuous nature of the former treatment compensates for the lower oxalate clearance by the peritoneum. The reported higher risk of oxalosis associated with intermittent peritoneal dialysis has led to a similar risk being postulated for CAPD; however, the present study indicates that if such a risk exists, it cannot be explained by higher levels of oxalate or ionized calcium in these patients.

The effect of vitamin C intake on plasma oxalate in patients on regular haemodialysis.

Plasma oxalate was measured on two occasions in 18 patients with end-stage renal failure on regular haemodialysis treatment: once while on a routine dose of vitamin C (100 mg/day) and subsequently after 2 weeks administration of a larger dose of vitamin C (500 mg/day). Pre- and post-dialysis concentrations were all markedly increased, reflecting the reduced glomerular filtration rate of end-stage renal failure. Both pre- and post-dialysis oxalate increased significantly following the increase in ascorbate dose but there was no significant correlation between plasma oxalate and ascorbate results. Considerations governing dosage of vitamin C in patients with chronic renal failure are discussed.

Effects of probucol on renal function in rats with bilateral ureteral obstruction.

To ascertain the potential role of reactive oxygen metabolites in the pathophysiology of obstructive uropathy, we examined the effect of probucol, an antioxidant agent, on renal function in normal rats and rats with unilateral release of bilateral ureteral obstruction (BUO) of 24 hours duration. Rats were fed either a standard diet or a standard diet containing one percent probucol for two weeks prior to study. Probucol lowered serum cholesterol in both normal and BUO rats. Probucol did not significantly affect renal function in normal rats. BUO rats given probucol had greater inulin and PAH clearances at three to five hours and three days following release of BUO than rats with BUO not given probucol. Kidneys from obstructed rats had higher levels of malondialdehyde, an index of lipid peroxidation, a greater number of leukocytes in the cortex, decreased levels of reduced glutathione and increased levels of oxidized glutathione. Renal cortex from obstructed rats treated with probucol had significantly higher levels of reduced glutathione than kidneys of obstructed rats not given probucol. A decrease in cholesterol, using another lipid-lowering agent, lovastatin, did not modify renal function in rats with BUO. The data can be interpreted to indicate a role for reactive oxygen species in the pathophysiology of obstructive nephropathy. The improved renal function seen in probucol-treated rats with BUO may be due to an effect of this agent in affecting accumulation of reactive oxygen metabolites and/or decreasing the number of leukocytes infiltrating the renal cortex.

A simple, rapid assay for plasma oxalate in uraemic patients using oxalate oxidase, which is free from vitamin C interference.

An enzymatic assay for the determination of oxalate in plasma was developed which is specific, simple, rapid and requires no specialised equipment; interference from vitamin C was removed by incubation of acidified plasma ultrafiltrate with ascorbate oxidase prior to oxalate estimation. Recoveries were 93 +/- 11% and the inter-batch coefficient of variation for 31 determinations at an oxalate level of 24 mumol/l was 10%. The assay is linear up to 300 mumol/l with a detection limit of 2 mumol/l. The reference range, based on results from 25 healthy volunteers, was defined as less than 2-5 mumol/l which is similar to levels established for the in vivo isotope dilution technique. The assay has an added advantage over the latter method, which requires a urine collection, in that it can be applied to plasma from anuric patients. A linear correlation (r = 0.68, p less than 0.001) was found between plasma oxalate and serum creatinine in individuals with varying degrees of renal failure.