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Biomedical subjects

K Iidaka

Publications and source records attributed to K Iidaka.

At least 19 recordsLinked to original sources
PubMed1996

Glomerulonephritis with predominant paramesangial IgG deposition.

The new clinicopathological entity, immunoglobin G (IgG)-associated mesangial proliferative glomerulonephritis (GN), has been reported recently, but serial renal biopsies were not performed in the cases reported. The findings of three serial renal biopsies in a pediatric case with IgG-associated GN and paramesangial deposits are reported. Microscopic hematuria was found incidentally at the age of 8 years and the hematuria often worsened transiently during periods of upper respiratory infections. The patient was treated mainly with dipyridamole. The third biopsy showed that both paramesangial hemispherical deposits and predominant mesangial IgG deposits had increased, while mesangial cell proliferation had markedly decreased. These serial biopsy findings suggest that IgG-associated GN with microscopic hematuria and slight proteinuria may be characterized by a relatively benign histological and clinical course, as described in recent reports.

Child↗
PubMed1996

Effects of dietary salt restriction on blood pressure and the renal vasoactive system in the congenitally bilateral hydronephrotic rat.

We examined the responses on blood pressure when the renal vasoactive system such as renin-angiotensin-aldosterone system (RAAS) and kallikrein-kinin system (KKS) was activated by dietary salt restriction in the congenitally bilateral hydronephrotic rat (BHN). In a low salt diet (LS)-normotensive and normal kidney control rats after 8 weeks from initiating dietary salt restriction, the plasma sodium concentration (PNa) was retained at a level similar to that in the normal diet (ND)-control rats, and plasma renin activity (PRA), plasma aldosterone concentration (PAC) and urinary kallikrein activity (UKA) were about 1.8-, 9.4-and 1.7-fold higher, respectively, than those in the ND-control rats. In addition, LS-control rats had a significantly (p < 0.001) high systolic blood pressure (163 +/- 2.0 mm Hg) compared with that (136 +/- 5.8) of ND-control rats. These results suggest that the activated renal vasoactive system acted for not only sodium retention but also for elevation of blood pressure in LS-control rats. In LS-BHN at week 8, PNa was also retained at a nearly normal level. However, the renal vasoactive system activation for sodium retention was higher than that of LS-control rats; that is, increase of PRA, PAC and UKA were about 3.8-, 24.7-and 10.0-fold, respectively, than in ND-BHN. The higher activation of RAAS, nevertheless, does not affect blood pressure in BHN; that is, both hypertension of BHN fed LS and ND developed similarly. These findings suggest that dietary salt restriction could markedly activate the renal vasoactive system for sodium retention without elevating blood pressure in BHN different from control rats.

Aldosterone↗
PubMed1995

Cytophagic histiocytic panniculitis in systemic lupus erythematosus.

This paper presents a case of cytophagic histiocytic panniculitis in a Japanese woman, who had systemic lupus erythematosus complicated with Hashimoto's thyroiditis and lupus nephritis from the age of 12. The patient had painful multiple purplish subcutaneous nodules on the face, trunk and extremities, high fever and liver dysfunction without coagulopathy. The histological features of the skin nodules were extensive histiocyte and/or macrophage infiltration often with leuko- and/or erythrophagocytosis in the subcutaneous fat tissue.

Adipose Tissue↗
PubMed1994

[Histopathological changes produced in organs by platelet activating factor].

This experiment was conducted to investigate the effect of platelet activating factor (PAF) on the pathological changes in organs using 10 mice (C3H/HeN). Ten mice were divided into two groups of acute and chronic experiment groups. In acute experiment, each mice received iv bolus injection of PAF 2.5 micrograms.kg-1 and in chronic experiment daily ip injection of PAF 7.5 micrograms.kg-1 for 7 days. Histopathology was observed with light microscopy after one hour or after 7 days by haematoxylin and eosin stain. In acute experiment, congestion of the lung, liver, kidney and spleen in all cases, right ventricular dilation in 2 cases and villous necrosis in the small intestine in 4 cases were observed. In chronic experiment, hyaline thrombus with congestion of the lung in 3 cases and congestion of the liver and kidney in all cases were observed. Splenomegaly with increased macrophage was observed, but no necrosis in the small intestine was observed. Marked findings were villous necrosis in the small intestine in acute experiment and hyaline thrombus in the lung as well as splenomegaly in chronic experiment.

Animals↗
PubMed1992

Induction of glomerular injury by singlet oxygen.

The role of the reactive oxygen species (ROS) in the induction of tissue injury has been well documented. Regarding glomerular injury, the focus of past studies has been on superoxide, hydrogen peroxide, hydroxyl radical and C10-. However, whether singlet oxygen, an exceptionally reactive oxygen metabolite, may cause glomerular lesions has not been investigated. In the present study we documented the effects of locally generated singlet oxygen in the kidney. To generate singlet oxygen, kidneys were perfused with the pigment pheophorbide a, which was followed by exposure to light. One hour after irradiation, severe morphological damage of the glomerular cell had developed. Extensive deposits of fibrin and accumulation of platelets were seen in the glomerular capillary lumina. By contrast, kidneys not exposed to light showed no, or only minimal, abnormalities. Glomerular injury was not inhibited by pretreatment with superoxide dismutase. These results suggest that singlet oxygen produced by pheophorbide a by photodynamic reaction leads to tissue injury in vivo.

Animals↗
PubMed1992

[The effect of elastase on aminonucleoside nephrosis--on renal vascular system].

This study was performed to investigated the relationship between cross sectional areas of glomerular arterioles and glomerular volume in rats with puromycin aminonucleoside (PAN)-induced nephrosis, which is an experimental model of glomerular sclerosis. We also evaluated the effect of an anti-arteriosclerotic agent, elastase on these parameters. Six-week-old male Sprague-Dawley rats were divided into 3 groups; control, PAN-treated (70 mg/kg i.p.), or PAN+elastase-treated (5 mg/kg/day i. m.) group. After 12 weeks of experimental period, microvascular cast of the kidney was prepared, and the cross sectional areas of afferent and efferent arterioles as well as glomerular volume were measured using scanning electron microscopy. In the juxtamedullary glomeruli with minor abnormalities, the efferent arteriole was narrower in PAN-treated rats than in the control rats and the elastase-treatment partially corrected it (control 55.7, PAN 35.9, PAN+elastase 43.7 x 10 microns 2). On the other hand, the cross sectional area of afferent arteriole was not different among the 3 groups. In glomeruli showing sclerosis, the cross sectional area of efferent arteriole correlated positively with the glomerular volume. There results suggest that constriction of the efferent arterioles contributes to the development of glomerular sclerosis in PAN-induced nephrosis. In addition, elastase possibly inhibits this process and thereby protect glomeruli from sclerosis.

Animals↗
PubMed1992

Mesangial anionic sites are decreased in human focal glomerular sclerosis.

We studied the mesangial anionic sites in two patients with focal glomerular sclerosis (FGS), using polyethyleneimine as a cationic probe. The mesangial negative charge in the FGS patients was less than that in three control patients. The decrease in negative charge in FGS concerned the central, paramesangial, as well as the subendothelial region of the mesangium; the decrease was most pronounced in the central region. It is proposed that loss of mesangial negative charge may have pathogenic significance in FGS.

Adolescent↗
PubMed1991

Morphometric analysis of the glomerular capillary area--a comparison of minimal change nephrotic syndrome, focal glomerular sclerosis, and pre-eclampsia.

A morphometric analysis was performed to compare the capillary area in non-sclerotic glomeruli in focal glomerular sclerosis (FGS), pre-eclampsia with focal sclerotic change of the glomeruli, and minimal change nephrotic syndrome (MCNS). The mean and standard deviation of the capillary area was greater in FGS than in pre-eclampsia and MCNS. Tubulo-interstitial lesions, such as tubular atrophy, interstitial fibrosis, and lymphocytic infiltration, were more severe in FGS than in pre-eclampsia. The presence of tubulo-interstitial changes including tubular atrophy and interstitial fibrosis with lymphocytic infiltration is thought to be an important prognostic factor in pre-eclampsia as well as in FGS. Unequal dilatation of the glomerular capillaries in non-sclerotic glomeruli may be harmful to the glomeruli and may lead to the development of glomerular sclerosis.

Adolescent↗
PubMed1991

Focal segmental glomerular hyalinosis and/or sclerosis in rats with congenital unilateral hydronephrosis.

Focal segmental glomerular hyalinosis and/or sclerosis (FSHS) was observed in five Wistar-Imamichi rats with congenital unilateral hydronephrosis (CUH rats). Marked proteinuria (164.9 +/- 138.4 mg/day) was observed in the CUH rats. Immunoperoxidase staining for IgM, C3 and IgG was positive in the glomeruli, showing in a focal, segmental pattern that corresponded to the areas of FSHS seen by light microscopy. These glomerular findings were extremely similar to those of human focal glomerular sclerosis (FGS). FSHS was found to be common to both the hydronephrotic kidney and the contralateral kidney without hydronephrosis. Morphometry revealed that the glomerular area of the juxtamedullary glomeruli was greater than that of superficial glomeruli in control rats (11,037 micron2 vs. 6,847 microns2). On the other hand, glomerular hypertrophy was observed in non-sclerotic glomeruli of CUH rats (superficial glomeruli; 12,477-16,123 microns2, juxtamedullary glomeruli; 14,635-18,418 microns2). Also, a decreased in the number of glomeruli within the range 1.8-4.1 per unit area (1 mm2) was seen in CUH rats compared with control rats (mean 4.4). These results suggest that the increased rate of development of FSHS is based on hyperfiltration in the remaining functional nephrons.

Animals↗
PubMed1991

Autosomal recessive polycystic kidney in rats.

We evaluated the characteristics of renal lesions in rat autosomal recessive polycystic kidney (ARPK). In rat ARPK, small cysts appeared primarily in the medulla 2 months after birth and gradually extended to the cortex, forming large cysts involving the entire layer after 8 months. By immunofluorescence microscopy, type IV collagen was more strongly stained in the epithelial basement membrane of the rat ARPK than in the normal rat tubular basement membrane (TBM). Electron microscopy demonstrated a marked thickening, slight splitting and lamination of the TBM in the ARPK. As peroxidase-labeled lectins, dolichos biflorus very strongly stained the cyst epithelium whereas lens culinaris did not. These findings indicate that cysts in rat ARPK originate in the collecting duct.

Age Factors↗
PubMed1991

Changes of anionic sites in the mesangium with aging in rats: a comparison of the immersion and intravenous PEI methods.

We investigated the changes in anionic sites of the mesangial matrix related to aging in rats, employing polyethyleneimine (PEI) as a cationic probe. We compared the numbers of anionic sites detected by the immersion method and by the intravenous administration of PEI. Analysis of the mean numbers of PEI particles per 0.1 micron2 in the mesangial matrix revealed a significant decrease related to aging. Our results suggested that there was no significant difference in efficacy between the immersion and intravenous methods. Loss of negative charge of the mesangial matrix is believed to promote mesangial dysfunction and the entrapment of macromolecular substances, and so to play an important role in the onset of glomerular sclerosis.

Aging↗
PubMed1991

Decreased anionic sites in different portions of the basement membrane in aminonucleoside nephrosis.

We induced aminonucleoside (AN) nephrosis in male Sprague-Dawley rats and evaluated the decreases in negative charge in the peripheral and proximal portions of the loop basement membrane and the basement membrane in the paramesangial area. Following intravenous injection of polyethyleneimine (PEI), the number of PEI granules per 0.1 micron 2 of the basement membrane, and those per 1 micron length of the lamina rara externa (LRE) and lamina rara interna (LRI) were counted in each portion under an electron microscope and compared with those in the control group. In the rats with AN nephrosis, the number of PEI granules per 0.1 micron 2 was significantly decreased in each portion of the basement membrane. However, the degree of decrease was similar among the 3 portions. The ratio of the numbers of granules in the proximal and paramesangial portions to that in the peripheral portion (peripheral:proximal:paramesangial) was 1:0.89:0.64 in the control group and 1:0.88:0.62 in the AN nephrosis group. Similar results were obtained for the numbers of PEI granules per 1 micron length of the LRE and LRI. These findings suggest that the negative charge is decreased in the loop basement membrane and paramesangial basement membrane in AN nephrosis, but the degree of decrease appears to be uniform.

Animals↗
PubMed1990

Portions of basement membrane with decreased negative charge in various glomerulonephritis.

The decrease in negative charge was evaluated in different portions of the basement membrane as well as the lamina rara externa (LRE) and lamina rara interna (LRI). The subjects were nine patients [2 patients with focal segmental glomerulosclerosis (FGS), 2 with membranoproliferative glomerulonephritis (MPGN), 3 with IgA nephropathy, and 2 with Henoch-Schoenlein purpura nephritis (HSPN)] and 2 patients with minor glomerular abnormalities and 1 with tubulo-interstitial nephritis (TIN) as controls. Polyethyleneimine (PEI) was used as a cationic probe. The basement membrane was divided into the peripheral portion (loop basement membrane 7 microns or more from the anchor portion), proximal portion (within 3 microns of the anchor portion), and the paramesangial portion in the paramesangial basement membrane. In each portion, PEI granules per 1 micron of the LRE and LRI were counted. Anionic sites were decreased in the patients with FGS and MPGN, but the damage pattern differed between the two diseases. In the patients with FGS, the decrease in anionic sites was most marked in the peripheral portion with an even greater decrease in the LRI. In the patients with MPGN, the decrease was uniform among the portions. On the other hand, no significant difference was observed in any portion between the patients with IgA nephropathy or HSPN and the controls. The portions with decreased negative charge varied among various glomerular diseases, suggesting different developmental mechanisms.

Adolescent↗
PubMed1989

[The effect of the elastase on aminonucleoside nephrosis].

In this paper, we studied the effect of elastase on aminonucleoside (AN) nephrosis which is considered a model of focal glomerular sclerosis (FGS). Elastase is an enzyme which disintegrates elastin, discovered by Balo, and used in the treatment of arteriosclerosis and hyperlipidemia. It has also been known to improve metabolism of acid mucopolysaccharides, so, this study focused on metabolic improvement. Three groups of male Sprague-Dawley rats were studied and observed at regular intervals; 30, 60, 90 days. The ANE group (AN + elastase) was administered one shot of AN (10 mg/100 g B.W.) during the test interval, while elastase (5 mg/kg B.W.) was injected 5 days/week for the entire test interval. The AN group was administered one shot of AN only. The third group was a control (C). The following results were observed: (1) Focal segmental hyalinosis and sclerosis (FSHS); ANE group was weaker than AN group. (2) Other significant qualifying glomerular changes (vacuolar change and hyaline droplets of the epithelial cells, adhesion, and foam cells); ANE group was weaker than AN group. (3) Anion loss in GBM was shown by a lack of colloidal iron staining under light microscopy, and by a lack of PEI particles under electron microscopy; there was significantly less anion loss with ANE group, than with AN group. The findings suggest that elastase has an affect on the metabolism of acid mucopolysaccharide and collagen in sclerotic lesion, and may restrain the progress of amino-nucleoside nephrosis.

Animals↗
PubMed1989

[Pathomorphological studies on arterial cushion. 2. Aminonucleoside nephrotic rat].

The present study is an attempt to solve the problem of pathogenesis of focal glomerular sclerosis (FGS), especially in juxtamedullary cortex, we were investigated by measurement of luminal diameters of afferent arterioles (Aff), efferent arterioles (Eff) of numerous glomeruli, arterial cushion (AC), afferent arterioles (AC-aff) at a region of branching arteries from the interlobular arteries, using scanning electron micrographs of methyl methacrylate casts of intrarenal arteries of aminonucleoside nephrotic rats. As regards luminal diameters, Eff were nearly equal Aff in minor glomerular abnormalities (Minor). Nevertheless Eff of glomeruli with segmental sclerosis (FSHS) were smaller than Aff (t-test). AC with FSHS were smaller than ones of Minor, statistically (t-test). The results of these examination, the cushion may be important factor for the regulation of blood flow in sclerotic glomeruli.

Animals↗
PubMed1989

Study of anionic sites on the mesangium in aminonucleoside nephrosis.

In recent years, various reports have appeared concerning anionic sites in glomerular lesions. However, no detailed results for anionic sites in the mesangium have been reported. The authors therefore prepared nephrotic rats by the administration of puromycin aminonucleoside (PA) and investigated the anionic sites in various mesangial regions, using polyethyleneimine (PEI) as a cationic probe. In the mesangium of the control group as well as the experimental groups, PEI particles were most numerous in the subendothelial regions, followed by the central region and paramesangial region, in that order. In the group treated with PA, the numbers of PEI particles in each mesangial region decreased as compared with those in the control group. Among the three mesangial regions considered, this decrease was most pronounced in the paramesangial region. In the group which received elastase, no significant decrease in numbers of PEI particles was observed in subgroups I and II, indicating maintenance of the anionic sites. The results obtained suggested that regional investigations of the mesangial matrix may be of considerable significance for elucidating the etiologic factors in glomerular sclerosis, and that negative charge impairment in the mesangial matrix plays an important role in the development of glomerular sclerotic lesions.

Animals↗
PubMed1989

[Pathomorphological studies on arterial cushion. 1. Rat normal kidney].

The present studies are an attempt to elucidate the vulnerability of focal glomerular sclerosis (FGS). The distribution and morphology of the arterial cushions were studied in rat renal arteries by light microscopy, transmission electron microscopy and scanning electron microscopy (SEM) using of the renal vascular casts. The arterial cushions were observed at a region of the branching arteries from the arcuate arteries and the interlobular arteries. They were extensively demonstrated mainly in the mid cortex and juxtamedullary cortex by the serial sections, but not in the subcapsular cortex. The arterial cushions showed valve-like protrusions and consisted of three components, such as the endothelial cells, the smooth muscular cells and the interstitial ground substances, electron microscopically. The cushions are covered by the endothelial cells which often showed various variation in thickness. Also these had deep processes which elongate into the interior of the cushions. The cells of interior portions of the cushions were modified smooth muscular cells. These cells contained numerous myofibrils and a large number of scattered glycogen granules. No nerve fibers were seen within the cushions. The modified smooth muscular cells were embedded in a loose matrix (probably acid mucopolysaccharides) which contained strands of basement membrane like material. The cushions were observed on the wall of the arcuate and interlobular arteries in the cortex except for subcapsular cortex by SEM. They showed elongated indentation surrounding lumen of their arteries. These results of the observation, the cushion may be important factor for the regulation of blood flow in small arteries and arterioles. The disorder of autoregulation of interlobular arteries due to dysfunction of the cushions with anionic loss were assumed to be one of the important factor in progress to the glomerular sclerosis.

Animals↗