Exposure of rat thymocytes to hydrogen peroxide increases annexin V binding to membranes: inhibitory actions of deferoxamine and quercetin.

Effects of hydrogen peroxide (H(2)O(2)) on rat thymocytes were examined, using a flow cytometer and three fluorescent probes, annexin V-fluorescein isothiocyanate (annexin V-FITC) for detecting phosphatidylserine expressed on the membrane surface, ethidium bromide for estimating dead cells, and fluo-3-acetoxymethyl ester (fluo-3-AM) for monitoring changes in intracellular Ca(2+) concentration ([Ca(2+)](i)), to characterize H(2)O(2)-induced cytotoxicity. Exposure to H(2)O(2) (30 microM or more) increased the number of annexin V-positive live cells dose- and time-dependently while the number of dead cells increased at concentrations of 1 mM or more. H(2)O(2) (30 microM or more) increased [Ca(2+)](i) in a dose-dependent manner. Threshold concentration of H(2)O(2) to increase [Ca(2+)](i) was similar to that to increase annexin V binding to membranes. The H(2)O(2)-induced change in cell membranes was attenuated under Ca(2+)-free conditions. Therefore, it is likely that Ca(2+) is involved in the H(2)O(2)-induced cytotoxicity. Deferoxamine was effective to protect the cells suffering from H(2)O(2)-induced oxidative stress, suggesting a contribution of hydroxyl radicals generated by the Fenton reaction. Quercetin also exerted a potent protective action on cells suffering from H(2)O(2)-induced oxidative stress. The results indicate that the exposure of rat thymocytes to H(2)O(2) at micromolar concentrations increases annexin V binding to cell membranes in a Ca(2+)-dependent manner, suggesting the possibility that the oxidative stress caused by H(2)O(2) (and/or hydroxyl radicals) induces apoptosis via increasing [Ca(2+)](i).

Acute interstitial nephritis and uveitis with bone marrow granulomas and anti-neutrophil cytoplasmic antibodies.

Acute interstitial nephritis (AIN) and uveitis of unknown etiology developed in a 15-year-old girl. Symptoms and urinary abnormalities improved spontaneously but moderate renal dysfunction and anterior uveitis persisted. A repeat biopsy performed 2 years later showed focal tubulointerstitial changes, while bone marrow examination revealed granulomas. Simultaneously, antineutrophil cytoplasmic antibodies (ANCA) were detected, and decreases in T cell population and lymphocyte function were found. These immunological abnormalities normalized in parallel with clinical improvement with corticosteroid therapy, strongly suggesting that in some patients autoimmune disorders contribute to the pathogenesis of the disease.

[Clinico-pathological study of carried-over patents with Henoch-Schönlein nephritis].

Fifty-two (49.5%) of 105 children with Henoch-Schönlein purpura developed nephritis. Eleven (21.1%) of 52 nephritic patients were carried over beyond childhood, while 21 (40.4%) cases had normalized urinalyses in childhood. The carried-over patients had a higher incidence of severe proteinuria and tubular atrophy compared to those of patients with normalized urinalyses (p < 0.05). These results suggest that patients with severe proteinuria and tubular atrophy tend to have persistent urinary abnormalities beyond childhood.

A monoclonal antibody (1G10) recognizes a novel human mesangial antigen.

We have identified a unique mesangial matrix protein of the human glomerulus by using a monoclonal antibody, 1G10, generated against culture human glomerular cells. By immunofluorescence, the antigen recognized by 1G10 (1G10 antigen) is present in mesangium and smooth muscle tissue and cannot be detected in any other tissue examined. Immunoelectron microscopy of glomeruli indicated that 1G10 antigen is present exclusively in the mesangial matrix at the endothelial-mesangial interface. The 1G10 antigen is also expressed by cultured mesangial cells, but not by cultured glomerular epithelial cells, umbilical endothelial cells or fibroblasts. 1G10 did not react with the mesangial matrix proteins [fibronectin (FN), laminin (LAM), collagen types I, III, IV, V, and VI (Col I, III, IV, V, VI), heparin sulfate proteoglycan (HSPG), or thrombospondin (TS)] present under normal and diseased states or smooth muscle antigens (myosin, actin), but did react with a 4 M urea extract of renal cortex and a 0.3% deoxycholate extract of isolated glomeruli. Two dimensional immunoblot analysis using the urea extract demonstrated the binding of 1G10 to an approximately 200 KDa polypeptide with pI 6.0. On one dimensional immunoblot this band did not show cross react with polyclonal antisera to FN, LAM, Col IV, V, VI, HSPG or TS. This mesangial matrix component is trypsin and periodate sensitive, suggesting that it has the character of glycoprotein. In renal biopsy specimens from patients with mesangial proliferative glomerulonephritis (GN) and membranoproliferative GN, the expression of the 1G10 antigen increased along with mesangial hypercellularity or increased accumulation of mesangial matrix, but decreased in completely sclerosed glomeruli. No significant changes in 1G10 antigen expression was observed in membranous GN or minimal change nephrosis compared to normal glomeruli. This study suggests that the 1G10 antigen may not only be a useful marker for the clinical assessment of GN, but may also serve as a potential tool for the study of the pathogenesis of glomerular diseases characterized by cellular proliferation and mesangial matrix expansion.

Acute tubulointerstitial nephritis associated with Yersinia pseudotuberculosis infection.

Two siblings infected with Yersinia pseudotuberculosis suffered from acute renal failure about 2 weeks after the onset of the disease. Renal histology in both siblings showed acute tubulointerstitial nephritis. Yersinia pseudotuberculosis type VB was isolated from feces of one of them, antibodies to Yersinia pseudotuberculosis type VB in their sera were elevated. The results of the present study suggest that acute renal failure complicating infections with Yersinia pseudotuberculosis is due to acute tubulointerstitial nephritis.

[A case of vasospastic angina: development of transient collateral circulation lessen the degree of myocardial ischemia during coronary artery spasm].

A 57-year-old man was admitted to our hospital because he had had attacks of chest pain at rest for more than a year, in spite of daily oral diltiazem (90 mg/day) and isosorbide dinitrate (15 m/day). The diagnosis of variant angina was made for him based on ST elevation in chest leads of the electrocardiogram during his first attack. However, one year later, the electrocardiograms during attacks showed only ST depression or T wave inversion in chest leads. The coronary arteriogram during spontaneous chest pain revealed that the left anterior descending artery was totally occluded at its middle portion, and that its peripheral portion was perfused by collateral circulation from the right coronary artery. The coronary arteriograms after administration of nitroglycerin were apparently normal, and no signs of collateral circulation were observed. These findings indicated that the transient collateral circulation could develop after repetitive coronary artery spasms even in the absence of significant coronary stenosis, and that it could lessen the degree of myocardial ischemia during coronary artery spasm.

IgA nephropathy in Japanese children and adults: a comparative study of clinicopathological features.

A comparative clinicopathological study was retrospectively performed in 61 children and 51 adults with IgA nephropathy. Hematuria and/or proteinuria as a chance finding was the most common initial clinical sign, being observed in 82.0% of the children and in 52.9% of the adults. At renal biopsy, hypertension and severe proteinuria were found in 9.8 and 33.3% of the adults and in 0 and 14.8% of the children (both p less than 0.05), respectively. Elevations of blood urea nitrogen and serum creatinine were found at this time of biopsy in 21.6 and 9.8% of the adults, but in none of the children (p less than 0.001 and p less than 0.05, respectively). Histologically, focal glomerulosclerosis and tubular atrophy were found in 52.9% of the adults and in 32.8% of the children (p less than 0.05). However, some features of the disease seen in both groups were similar, including the incidences of IgA nephropathy, sex ratio, the mode of onset, incidences of gross hematuria, and high IgA levels in the sera. Furthermore, the relationships between the severity of proteinuria and renal lesions were similar: mesangial proliferation, glomerulosclerosis, and tubular atrophy increased with the degree of the severity of proteinuria. These results suggest that IgA nephropathy is essentially identical in children and adults, although adult patients tend to be further advanced in their disease course at the time of diagnosis, and that focal glomerulosclerosis with tubular atrophy is correlated with deterioration of renal function.

[IgA nephropathy in Japanese children and adults: a comparative study of clinico-pathological features].

A comparative clinico-pathological study was performed on 61 children and 51 adults with IgA nephropathy. Hematuria and/or proteinuria found by chance was the most common initial clinical sign, being observed in 82.0% of the children and 52.9% of the adults (p less than 0.001). At renal biopsy, hypertension and severe proteinuria were found in 9.8% and 33.3% of the adults and 0 and 14.8% of the children (p less than 0.05, p less than 0.05). Elevations of blood urea nitrogen and serum creatinine were found at the time of biopsy in 21.6% and 9.8% of the adults but in none of the children (p less than 0.001, p less than 0.05). On histological studies, proliferative changes of the glomerulus were similar in the two groups, and diffuse mesangial proliferation was found in 62.3% of the children and 51.0% of the adults (although the difference was not significant). Focal glomerulosclerosis and tubular atrophy were found in 52.9% of the adults and 32.8% of the children (p less than 0.05). These results suggest that focal glomerulosclerosis with tubular atrophy is correlated with deterioration of renal function, hypertension and age at renal biopsy, and has an important influence on the prognosis of patients with IgA nephropathy.

Ultrastructural alterations of glomerular anionic sites in IgA nephropathy.

The ultrastructural alterations of glomerular anionic sites were studied in biopsy specimens from 34 patients with IgA nephropathy using polyethyleneimine (PEI). Prominent common findings in the glomeruli of the patients were few PEI particles in electron dense deposits in the mesangial and subepithelial area and marked reduction in glomerular anionic sites covered with deposits. The anionic sites of the glomerular basement membrane (GBM) and epithelial cell surface coat (ESC) appeared unaltered in the patients with hematuria and/or mild proteinuria. But in patients with proteinuria in the nephrotic range, focally discrete loss of anionic sites in the lamina rara externa (LRE) was seen and the number of anionic sites of the ESC were decreased with retraction of the foot processes. The anionic sites of the lamina rara interna showed much less change in these patients. Subepithelial deposits were often seen concomitantly with focal loss of anionic sites in the LRE at the site of the deposits, but subendothelial deposits had little influence on the anionic sites of the neighboring GBM. The anionic sites of GBM that showed focal thinning with small GBM projections were appreciably decreased in number, but those in split GBM were not decreased. These results suggest that either loss of the negative charge on the glomerular capillary wall associated with subepithelial immune deposition or morphological changes of the GBM contribute to the progression of proteinuria in IgA nephropathy.