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Z Ota

Publications and source records attributed to Z Ota.

At least 19 recordsLinked to original sources

Massive eosinophilic infiltration in a patient with the nephrotic syndrome and drug-induced interstitial nephritis.

The pathologic feature of acute interstitial nephritis is the infiltration of mononuclear cells, predominantly lymphocytes and monocytes, into the interstitium. We present an unusual case of a 49-year-old man with drug-induced acute interstitial nephritis whose renal biopsy specimen showed a massive infiltration of eosinophils into the interstitium and eosinophils infiltrating into the glomerulus through a gap in Bowman's capsule and the juxtaglomerular zone. The patient initially was referred to us with a recurrence of the nephrotic syndrome. Deterioration of renal function and an increase in proteinuria was noted at that time. Triazolam, a sleep inducer, was the suspected cause of the acute interstitial nephritis. Renal biopsy revealed sclerotic glomeruli containing eosinophils among massive infiltrated eosinophils and a loss of endothelial cells and mesangial cells in contrast to a preservation of epithelial cells. Infiltrating eosinophils were directly attached to the glomerular basement membrane, and free granules from the eosinophils were observed in the capillary lumen. In addition to chronic sclerotic change, eosinophils may have further damaged the glomerular capillary wall, leading to an increased severity of proteinuria in this case.

Eosinophilia

Distribution of extracellular matrix receptors in various forms of glomerulonephritis.

Integrins are heterodimeric transmembrane receptor glycoproteins consisting of alpha and beta subunits that mediate adhesion and interactions between cells and extracellular matrix. Such interactions may be perturbed in various pathologic states, resulting in the altered phenotypic expressions of the integrins in affected tissues. To ascertain the alterations in integrins in various renal diseases, their distribution was investigated in different forms of glomerulonephritis by indirect immunofluorescence and immunoelectron microscopy using specific antibodies directed against beta 1 integrins and integrin alpha v beta 3 (vitronectin receptor). In addition, the distribution of certain extracellular matrix components (ie, fibronectin, vitronectin, and type IV collagen) was examined. Integrin beta 1 and alpha v beta 3 were highly expressed in proliferating mesangial cells in immunoglobulin A nephropathy, membranoproliferative glomerulonephritis type I and diffuse proliferative lupus nephritis. Their putative ligands (ie, fibronectin, vitronectin, and type IV collagen) also were increased in the expanded mesangial regions. In immunoglobulin A nephropathy, integrin beta 1 and alpha v beta 3 were seen by immunoelectron microscopy to be localized to the mesangial cell membranes in close proximity to the immune complex deposits; however, fibronectin and vitronectin immunoreactivities were observed in the mesangial immune complex deposits. Similarly, vitronectin also was detected in the immune complex deposits of other forms of proliferative nephritis, ie, membranoproliferative glomerulonephritis type I and diffuse proliferative lupus nephritis. In diffuse proliferative lupus nephritis, the cellular crescents displayed immunoreactivity toward integrin alpha v beta 3 and vitronectin. In nonimmune complex glomerular disease associated with nephrotic syndrome (ie, minimal change nephrotic syndrome), integrin alpha 3 beta 1, which normally has a linear capillary distribution, was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Collagen

Ultrastructure of nonenzymatically glycated mesangial matrix in diabetic nephropathy.

Advanced protein glycation has been proposed as a major factor in the development of diabetic nephropathy. Advanced glycation end products (AGEs) have altered the structure of extracellular matrix component and impaired self association in vitro. To elucidate the role of AGEs in the progression of diabetic nephropathy, the present study was undertaken to localize glomerular AGEs immunohistochemically. Ultrastructural changes of the mesangial matrix were analyzed with high resolution scanning electron microscopy. No glomerular AGEs staining was noted in normal control kidney specimens, or in tissue from glomerulonephritis patients without diabetes mellitus. The mesangium showed a positive AGEs staining in advanced stages of diabetic nephropathy, and the most characteristic finding was the strong AGEs staining in nodular lesions. By high resolution scanning electron microscopy, control and diabetic mesangial matrices revealed a meshwork structure composed of fine fibrils (10 nm in width) and numerous pores (12 to 13 nm in diameter). In the nodular lesions, however, loosening of the meshwork was significant, and the diameter of the pores was enlarged (approximately 24 nm). This study provides the first immunohistochemical evidence that AGEs are localized in diabetic glomeruli, most notably to nodular lesions. Advanced glycation might play a role in the progression of diabetic nephropathy through impairment of the assembly of matrix proteins in vivo.

Adult

Minimal-change nephrotic syndrome associated with systemic lupus erythematosus.

A case of systemic lupus erythematosus (SLE) associated with minimal-change nephrotic syndrome (MCNS) is described. A 41-year-old woman with SLE presented with symptoms of nephrotic syndrome. Renal biopsy revealed minor glomerular abnormalities without the deposition of immune complexes. The initial heavy proteinuria promptly decreased after the prednisolone dosage was increased and disappeared 4 weeks later. The patient had a relapse of nephrotic syndrome without exacerbation of immunoserological reactions when the prednisolone dose was subsequently decreased. Remission was achieved 5 days after methylprednisolone pulse therapy. T cell dysfunction, which is present both in SLE and MCNS, might have triggered MCNS during the course of SLE.

Adult

Effect of vasopressin V1- and V2-receptor stimulation on blood pressure in DOCA-salt hypertensive rats.

We recently reported that stimulation of the arginine vasopressin (AVP) V1-receptor enhanced the pressor response in spontaneously hypertensive rats (SHR). In the present study, we investigated acute changes in systolic blood pressure (SBP) and heart rate (HR) after intravenous injections of AVP, OPC-21268 (a V1-receptor antagonist), and OPC-31260 (a V2-receptor antagonist), in anesthetized DOCA-salt hypertensive rats (DOCA) and age-matched sham-operated Wistar rats (control) to determine whether the pressor effect is specific to SHR or is present in other hypertensive animal models. SBP increased significantly in DOCA rats 9 min after injection of AVP 5 ng/kg without a concomitant increase in HR. Neither OPC-21268 3mg/kg nor OPC-31260 3mg/kg caused significant changes in SBP or HR. SBP tended to increase when AVP was administered after injection of OPC-31260. HR increased significantly 15 min after the combined treatment with OPC-31260 and AVP in DOCA rats compared with control rats. SBP did not change significantly when AVP was administered after injection of OPC-21268 in DOCA or control rats, but HR decreased significantly from 1 to 4 min after injection of AVP in DOCA rats. Our results suggest that V1-receptor stimulation does not enhance the pressor response in the DOCA rat, which is a model of volume-dependent hypertension, suggesting that the AVP system, especially V1-receptor, is not as important in the development or maintenance of hypertension in DOCA rats as in SHR.

Animals

[Activation of complement during hemodialysis].

In hemodialysis using 3 types of dialysis membrane materials [regenerated cellulose (RC), cellulose triacetate (CTA), and polysulfone (PS)], activation of the complement, reduction of white blood cells, and variation of vitronectin (VN) were observed. RC membrane caused a significant reduction of white blood cells and elevations of Bb and soluble membrane attack complex (S-MAC), indicating a strong activation of the alternative complement pathway. Especially, the increase of S-MAC persisted for a long time during hemodialysis. Because reduction of VN was transient, it was assumed that the S-MAC escaping removal by VN receptors might have persisted in the circulation. These findings suggested that S-MAC would become useful as an index for evaluating biocompatibility of various artificial organs including dialysis membranes.

Aged

Developmental change of kidney dopamine receptors in spontaneously hypertensive rats.

To elucidate the role of the kidney dopamine system on blood pressure regulation, we investigated the developmental change of kidney dopamine receptors in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. The autoradiogram of [3H]-SCH23390, a specific DA1 receptor antagonist, showed that DA1 receptors were localized mainly in the rat renal cortex. The radiolabeled receptor assay (RRA) of [3H]-spiperone was performed on 3-, 7-, and 18-week-old SHR using the homogenate of renal cortex. Neither dissociation constant (Kd) nor maximum binding capacity (Bmax) were different between SHR and WKY rats at the age of 3 and 7 weeks. Nevertheless, Kd and Bmax were significantly low in 18-week-old SHR. The systolic blood pressure of 7-, and 18-week-old SHR was significantly higher than that of age matched WKY rats. The urinary dopamine excretion in 16-week-old SHR was significantly higher than that in age-matched WKY rats, although urine volume and urinary sodium excretion were the same as those in the control in both sodium-loaded and -restricted state. In summary, although renal dopamine production was enhanced in SHR in the hypertensive state, dopamine was found not to contribute to natriuresis since the number of dopamine receptors was reduced in these rats. We also found that enhanced dopamine production in response to a salt load was lacking in these rats. These two pathological phenomena noted in the renal dopamine system play a role in the progression of hypertension in SHR.

Aging

Changes in plasma concentrations of vitronectin in patients with diabetic nephropathy.

To investigate the role of vitronectin in the progression of diabetic nephropathy, plasma concentrations of vitronectin were measured by enzyme-linked immunosorbent assay in patients with diabetes mellitus and compared with normal control subjects. In diabetic patients with normoalbuminuria and microalbuminuria, plasma concentrations of vitronectin were significantly higher than those of control subjects. Plasma concentrations of vitronectin in diabetic patients with chronic renal failure were significantly lower than those with normal renal function. There was a significant positive correlation between plasma concentration of vitronectin and blood platelet counts. In the early stage of diabetic nephropathy, vitronectin may be increased caused by synthesis from activated platelets. With progression of diabetic nephropathy, plasma vitronectin may be decreased because of accumulation in sclerotic glomeruli and arteriosclerotic lesions. In conclusion, the plasma concentration of vitronectin appears to be an important marker for the progression of diabetic nephropathy.

Aged

The magnocellular arginine-vasopressin mRNA responds differently to food deprivation between the supraoptic and paraventricular nuclei of the hypothalamus in adrenalectomized rats with low corticosterone replacement.

We previously reported that food deprivation significantly decreased arginine-vasopressin (AVP) mRNA levels in the supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus and also greatly stimulated the pituitary-adrenocortical system in rats. In this study, we deprived adrenalectomized rats with subcutaneously implanted low-dose corticosterone pellets (ADX + B) of food for 3 days to investigate the involvement of corticosteroid feedback regulation in the food deprivation-induced decrease in AVP mRNA in both the SON and the PVN. The plasma corticosterone levels in these animals were maintained at low levels constantly over 24 h. The ACTH concentration in the morning plasma was markedly increased in the food-deprived ADX + B rats as compared to the fed ADX + B rats. Food deprivation significantly decreased the corticotropin-releasing hormone (CRH) content in the median eminence and increased the CRH and AVP content in the neurointermediate lobe of the pituitary. Semiquantitative in situ hybridization histochemistry revealed that AVP mRNA levels were decreased in the SON but, inversely, increased in magnocellular as well as parvocellular subdivisions of the PVN following food deprivation. These results suggest that: (1) AVP mRNA responds differently to food deprivation between the SON and the PVN; (2) the glucocorticoid feedback can exert on AVP mRNA in the PVN but not in the SON in the food-deprived rats; and (3) food deprivation affects the neurohypophysial levels of CRH and AVP.

Adrenalectomy

Glomerular extracellular matrices in rat diabetic glomerulopathy by scanning electron microscopy.

Characteristic pathological changes in the glomeruli in diabetic nephropathy include expansion of the mesangial matrix and thickening of the glomerular basement membrane (GBM). Using an acellular digestion technique combined with scanning electron microscopy, the three-dimensional ultrastructural changes in glomerular extracellular matrices were studied in rats with diabetic glomerulopathy. Diabetes was induced by the intravenous injection of streptozotocin and morphological analyses were performed 3, 6 and 11 months after the injection. Expansion of mesangial area and GBM thickening became evident with time. After treatment with the series of detergents, all cellular components were completely removed leaving the extracellular matrices intact. In normal controls, the mesangial matrix appeared as fenestrated septa with oval or round stomata between the glomerular capillaries. In diabetic glomerulopathy, expansion of mesangial matrix and narrowing of the mesangial fenestrae were observed. These changes in the mesangial matrices seem to play a vital role in the progression of glomerulosclerosis in rat diabetes. A subendothelial thin layer of the GBM was continuous with the mesangial matrix. One cause of GBM thickening in streptozotocin diabetes may be expansion of the mesangial matrix into the peripheral GBM.

Animals

Central interaction between endothelin and brain natriuretic peptide on vasopressin secretion.

OBJECTIVE: To examine the interaction between i.c.v. administration of endothelin and brain natriuretic peptide (BNP) on vasopressin (AVP) secretion in unanesthetized, freely moving rats. METHODS: I.c.v. cannulation and femoral artery catheterization were performed 7-8 days and 2 days before the experiment, respectively. Endothelin and BNP were injected into the third ventricle through the guide cannula. One millilitre of blood was collected for AVP measurement 30 min before and 10 min after i.c.v. injection. RESULTS: Central administration of endothelin (20 or 40 pmol/2 microliters) dose-dependently evoked the elevation of plasma AVP levels. Preinjection of BNP (0.2 or 1 nmol/3 microliters, i.c.v.) dose-dependently attenuated central endothelin (40 pmol/2 microliters)-induced plasma AVP secretion. CONCLUSIONS: We have already reported that BNP attenuated central endothelin-induced pressor response and plasma catecholamine secretion. Taken together, the results indicate that BNP attenuated central endothelin-induced pressor response, at least partially, by suppressing sympathetic nervous system activation and plasma AVP secretion.

Animals

A case of nephrotic syndrome and renal dysfunction in a pregnant woman with diabetes mellitus.

A 29-year-old diabetic woman who developed severe anaemia, nephrotic syndrome, and hypertension before the 28th week of gestation, had residual evidence of toxaemia and renal dysfunction more than 1 month following delivery. The histopathological findings of renal biopsy specimens were considered most consistent with toxaemia of pregnancy complicated by diabetic glomerulosclerosis. We consider that rapid acceleration of renal dysfunction may have been induced by: (1) poor control of diabetes before pregnancy; (2) glomerular hyperfiltration of the remnant nephrons throughout pregnancy; (3) hypercoagulopathy associated with pregnancy; (4) appearance of hypertension following these three conditions.

Adult

Serum and urinary concentrations of type IV collagen and laminin as a marker of microangiopathy in diabetes.

Serum and urinary concentrations of type IV collagen and laminin were measured by enzyme-linked immunosorbent assay (ELISA) in diabetic patients and compared with normal control subjects. In diabetic patients with proteinuria or with renal insufficiency, serum and urinary concentrations of type IV collagen were higher than those of control subjects (p less than 0.005). Furthermore urinary concentrations of type IV collagen and laminin were significantly higher in diabetes, even in the absence of nephropathy, than in normal controls (p less than 0.05). Urinary concentrations of type IV collagen in patients with diabetes and microalbuminuria (0.73 +/- 0.11 mg mmol-1) were significantly higher than in diabetic patients without nephropathy (0.40 +/- 0.060 mg mmol-1) (p less than 0.025). Urinary concentrations of type IV collagen may have a role as an indicator of early diabetic nephropathy. Serum concentrations of type IV collagen in diabetic patients with retinopathy were significantly higher than in normal controls (p less than 0.025). However, urinary concentrations of type IV collagen (p less than 0.05) and serum concentrations of laminin (p less than 0.025) were significantly higher in diabetic patients than normal controls and the difference between patients with and without retinopathy was not significant.

Albuminuria

Heparan sulfate proteoglycans are lost in patients with diabetic nephropathy.

The pathogenesis of diabetic nephropathy relative to the changes in the glomerular extracellular matrices was investigated. Renal tissues from 10 diabetic patients were immunostained with antibodies directed against heparan sulfate proteoglycans (HS-PGs), laminin, type IV collagen and fibronectin. Seven patients were nephrotic and had advanced glomerulosclerosis with nodular lesion, while the other 3 had no renal manifestations or minor glomerular tissue alterations. Controls included kidneys removed from patients with renal tumors and specimens obtained by renal biopsy from patients with IgA nephropathy. Relationships among proteinuria, intensity of fluorescence and glomerular changes were studied. In diabetes 3 patients with minor glomerular lesions were found to have no changes in various components of extracellular matrices. A marked reduction in the intensity of staining with anti-HS-PG antibodies was observed in renal specimens from patients with nodular glomerulosclerosis and proteinuria, while a mild decrease in the intensity of fluorescence was observed in tissues stained with antilaminin antibodies. An increase compared to normal control sample findings in type IV collagen and fibronectin was observed in the mesangium of sclerosing glomeruli. No loss of HS-PG was observed in patients with IgA nephropathy. These results indicate that glomerular extracellular matrix HS-PG is lost in association with diabetic nephropathy; this loss results in alteration of the charge-selective properties of glomerular capillaries. This alteration may, in part, be the cause of the proteinuria associated with diabetic nephropathy.

Adult