Mitsumasa Nagase

Improvement of proteinuria in a case of hepatitis B-associated glomerulonephritis after treatment with interferon

Disappearance of proteinuria was observed in a patient with hepatitis B-associated chronic glomerulonephritis after treatment with leukocyte interferon. The decrease of proteinuria was preceded by the disappearance of both deoxyribonucleic acid polymerase activity and hepatitis B e antigen from the patients sera.

Renal involvement in mixed connective tissue disease. Report of 5 cases.

5 cases with the compatible serological criteria of mixed connective tissue disease described earlier are presented. In 1 of them with a moderate degree of proteinuria, the renal biopsy disclosed membranous nephritis. However, despite the absence of overt clinical renal disease in the other 4 cases, biopsies disclosed membranous nephritis in 1 and mild mesangial proliferative glomerulonephritis in the remaining 3 cases. In the follow-up of these 4 cases, 2 subsequently developed abnormal urinalysis. Electron microscopic examinations demonstrated electron-dense deposits in glomeruli, and 4 of these patients also had microtubular structures in the endothelial cytoplasm. Contrarily to the original concept, our findings suggest that mixed connective tissue disease also induces immune complex disease.

Determination of urokinase in the urine of healthy volunteers and patients with renal diseases

A sensitive enzyme immunoassay was developed for the determination of urokinase in the plasma and urine. Normal human urine contained 2.68 +/- 0.36 u/ml of UK. Gel filtration of the mixture of normal urine resulted in 2 peaks in the profile, one with molecular weight of 32,000 and the other with molecular weight of 22,000. Patients with glomerulonephritis had higher UK levels. Kidneys with minimal changes and mild type or with the inactive phase of systemic lupus erythematosus (SLE) secreted relatively high levels of UK in the urine.

Interstitial Inflammatory and Chronic Tubulointerstitial Lesions in Lupus Nephritis: Comparison with Those in IgA Nephropathy

Correspondence: T. Yamamoto, M.D., First Department of Medicine, Hamamatsu University School of Medicine, 3600 Handa-cho, Hamamatsu, Shizuoka 431-31, Japan. The significance of interstitial inflammatory and chronic tubulointerstitial lesions was studied in relation to the severity of glomerular lesions in 62 patients with lupus nephritis and 88 with IgA nephropathy. Severe interstitial inflammatory and chronic tubulointerstitial lesions were found in patients with severe glomerular lesions in both lupus nephritis and IgA nephropathy. In such cases, the serum creatinine levels at biopsy were high and the renal prognosis was poor regardless of the underlying disease (lupus nephritis or IgA nephropathy). No IgA nephropathy patients with nil or mild glomerular lesions had moderate or severe interstitial inflammatory and/or chronic tubulointerstitial lesions. In contrast, predominantly severe interstitial inflammatory lesions were found in 36% of lupus nephritis patients with nil or mild glomerular lesions. The prevalence of interstitial immune complexes deposition was markedly high in those with predominant interstitial inflammatory lesions. However, the severity of chronic tubulointerstitial lesions was mild and renal function did not deteriorate in the mean follow-up periods of 68.6 months. It is suggested that, besides the tubulointerstitial lesions attributable to the severe concomitant glomerular damage, the interstitial deposition of immune complexes per se plays a pathogenic role in the interstitial inflammatory lesions in lupus nephritis. Its prognostic significance, however, was considered to be minor.

Suppression of Proteinuria by Dipyridamole in Rats with Aminonucleoside Nephropathy

Nephrosis was induced by single injections of puromycin of aminonucleoside to rats which were divided into two groups; the experimental group receiving dipyridamole in addition to aminonucleoside and the control group receiving aminonucleoside alone. 24-hour urinary albumin increased in rats of both groups after aminonucleoside injections. However, the experimental rats excreted significantly less albumin than controls. On the contrary, there was no significant difference in urinary IgG between the two groups. The stainings of anionic sites of glomerular basement membrane using ruthenium red revealed the reduction of anionic charge in the glomerular basement membrane of both groups, but the decrease of anionic charge was suppressed in lamina rara interna of the experimental rats. Considering the role of charge barrier in the glomerular basement membrane, it is concluded that the maintenance of anionic charge in experimental rats is causally related to the suppressed excretion of albumin.

Renal Hemodynamics in Oliguric and Nonoliguric Acute Renal Failure of Rabbits

The role of renal hemodynamic alterations in the curtailment of renal functions was studied in uranyl acetate-induced oliguric (ORF) and nonoliguric (NORF) renal failures of rabbits. 5 days after drug injection, renal functional and morphological changes were most remarkable. A depression of Cin and elevation of serum creatinine concentration were more marked in ORF than in NORF. Renal blood flow was high as compared to controls. Cortical blood flow redistributed to the inner cortex. There was no significant difference in renal blood flow or cortical flow distribution between renal failure models. The findings suggest the minor roles of renal blood flow and cortical flow distribution in maintaining renal failure in these nephrotoxic models. Prominent tubular necrosis was found in ORF but not in NORF. Arterial inulin concentration during retrograde ureteral infusion of 14C-inulin solution was significantly high in ORF as compared to controls and NORF. However, this inulin leakage was too small to explain severely curtailed inulin clearance.

Intraglomerular fibronectin in rat experimental glomerulonephritis.

SummaryTo clarify the mechanisms of glomerular pericapillary fibronectin deposition in human membranous nephropathy and mesangial proliferative glomerulonephritis, intraglomerular fibronectin distribution was examined by light and electron microscopy using the experimental rat models of Heymann and nephrotoxic serum nephritis. As previously demonstrated by immunofluorescence microscopy (Pettersson and Colvin 1978; Ikeya et al. 1985, 1986), fibronectin was distributed in the mesangial areas and occasionally on percicapillary walls of normal glomeruli, while in nephrotoxic serum nephritis and Heymann nephritis, fibronectin was diffusely located along glomerular capillary walls as well as in the mesangium. By immunoelectron microscopy using the immunogold technique, fibronectin was also noted in the mesangial areas and the lamina densa of the glomerular basement membrane (GBM) in normal glomeruli. In nephrotoxic serum nephritis, fibronectin was seen around mesangial cells situated between endothelial cells and the GBM, suggesting that pericapillary fibronectin in nephrotoxic serum nephritis reflects mesangial extension. However, in Heymann nephritis, it was found uniformly in the lamina rara interna, lamina densa and lamina rara externa of the GBM, indicating no specific relation to glomerular cells. When sections of normal and both experimental nephritis kidneys were incubated with fluorescein isothiocyanate conjugated with rat plasma fibronectin, a linear pattern of fluorescein staining along the glomerular capillary walls was observed in Heymann nephritis but not in normal or nephrotoxic serum nephritic rats. The GBM in Heymann nephritis would thus appear to have an affinity for plasma fibronectin. Based on the above findings, fibronectin in the GBM of rats with Heymann nephritis may reasonably be concluded to originate from the plasma.

Relationship between urinary fibrinogen degradation products and various types of chronic nephritis.

The concentration of urinary fibrin(ogen) degradation products (FDP) was determined by using enzyme immunoassay and radio immunoassay, and their urinary levels were compared with histologically classified types of glomerulonephritis. Urinary FDP levels were higher in the severe type of proliferative glomerulonephritis and at the active phase of systemic lupus erythematosus (SLE). They were also high in the membranous glomerulonephritis. Molecular weight of urinary FDP of a patient with severe proliferative glomerulonephritis was determined to be 150,000 and 68,000, respectively after gel filtration. Urinary FDP levels were higher in patients with glomerular fibrin deposit than in patients without fibrin deposit or normal volunteers. The amounts of excreted protein in urine was not related to the amounts of FDP. Decrease in the reciprocal of serum creatinine levels resulted in high urinary FDP levels, indicating that high urinary FDP levels may represent deterioration of renal function.

Renal Handling of Salt and Water in the Early Stage of Obstructive Jaundice in Rabbits

Renal handling of salt and water in the early stage of obstructive jaundice was studied in rabbits 10 days after the ligation of the common bile duct (BDL). Sham-operated (SO) animals served as controls. No sodium retention was found in BDL rabbits, despite reduced renal perfusion and elevated plasma aldosterone level. A redistribution of intrarenal blood flow was not found. The filtration fraction did not change. A saline load resulted in decreases in arterial hematocrit and total serum proteins, and increases in urine output, urinary sodium excretion and osmolal clearance. Blood pressure, glomerular filtration rate (GFR), RPF, the filtration fraction and the intrarenal flow distribution were not significantly affected by the saline load. No significant difference was found in the natriuretic response to the saline load between the BDL and SO groups. After 60 h of water deprivation, there was no significant difference in urine-to-plasma osmolality ratios or renal tissue fluid osmolality between the BDL and SO animals. The findings indicate that renal handling of salt and water was well maintained in the early phase of obstructive jaundice in rabbits. The data also suggest the critical role of the redistribution of intrarenal blood flow rather than of GFR or aldosterone in determining sodium retention in obstructive jaundice.

Inhibitory effect of lysozyme on the intraglomerular immune complex formation in lupus mice

The effect of lysozyme on intraglomerular immune complex deposition was examined in NZB/W F1 mice undergoing unilateral nephrectomy. Unilateral nephrectomy enhanced the glomerular immune complex deposition and glomerular lesions, which were suppressed by repeated intraperitoneal injections of lysozyme, in spite of unaltered serum anti-DNA antibody titers. DNA binding to the glomerular basement membrane (GBM) examined in vitro and that to glomeruli examined in vitro were also suppressed by lysozyme. An increased survival rate and decreased proteinuria were also induced by this basic protein. The mechanisms of the ameliorative effect were studied in vitro. DNA was bound to the GBM only in the presence of serum, plasma, or fibronectin. A similar inhibitory effect on DNA binding was also obtained by another polycation, hexadimethrine, in place of lysozyme. The in vitro findings suggest that DNA binding to the GBM is mediated by fibronectin, and that lysozyme electrostatically inhibits this binding, thereby possibly reducing the in situ DNA-anti-DNA complex formation in the GBM.