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Biomedical subjects

Z Ota

Publications and source records attributed to Z Ota.

At least 73 records · Page 4Linked to original sources
PubMed1994

Immunoreactivity of the JK-132 monoclonal antibody directed against basement membrane collagen in normal and diabetic glomeruli.

The possible involvement of basement membrane-associated collagen (recognized by the monoclonal antibody JK-132) in the evolution of diabetic nephropathy was studied in kidney specimens from seven patients with noninsulin-dependent diabetes mellitus, and its distribution was compared with those of antibodies against alpha 1 to alpha 4 chains of type IV collagen. JK-132, a monoclonal antibody against basement membrane-associated collagen, reacted immunohistochemically exclusively with the mesangial matrix of the glomerular capillary. In contrast, antibodies to the alpha 1 and alpha 2 chains (IV) reacted strongly with mesangial matrix, and less strongly with the glomerular basement membrane (GBM). Antibodies to the alpha 3 and alpha 4 chains (IV) reacted mainly with GBM. In diabetes, JK-132 reacted most extensively with the expanded mesangial matrix, its staining intensity increasing with progression of the diabetic glomerulosclerosis. Antibodies to the alpha 1 and alpha 2 chains (IV) reacted prominently with the expanded mesangial matrix but less strongly with the GBM. Antibodies to the alpha 3 and alpha 4 chains reacted intensely with the thickened GBM. These results suggest that basement membrane-associated collagen differs from alpha 1 to alpha 4 chains of type IV collagen and that basement membrane-associated collagen is a good marker of mesangial expansion in diabetic nephropathy.

Aged↗
PubMed1994

Effects of chronic, urea-induced osmotic diuresis on kidney weight and function in rats.

To study the effects of chronic osmotic diuresis which were not associated with hyperglycaemia on the rat kidney, osmotic diuresis was induced by i.v. infusion of urea. A 5 mol/l urea solution was continuously infused at a rate of 100 ml.kg-1 x day-1 on the basis of body weight on day 0. Duration of infusion was 2, 6, 10 or 14 days. Control rats received continuously infused Ringer's solution. Urea-treated groups developed osmotic diuresis (urine flow = about 0.04 ml.min-1 x 100 g body weight-1) comparable to that in rats with experimental diabetes mellitus induced by i.v. streptozotocin (55 mg/kg), however urea-induced osmotic diuresis was not associated with blood glucose level increases. Compared with their controls, rats receiving urea for 2-14 days had markedly increased kidney weight. Rats receiving urea for 10 days showed greatest kidney weight increase, 0.565 +/- 0.044 g/100 g body weight (mean +/- SD), representing a 53% increase compared with the control (0.369 +/- 0.034 g/100 g body weight). Kidney weight was associated with increases in kidney protein content. In contrast, none of control kidney weight values differed significantly from day 0 values (= normal rats; 0.387 +/- 0.028 g/100 g body weight). Creatinine clearance values in urea-treated groups were also higher than those in controls. The maximum value, 0.65 +/- 0.17.ml-min-1 x 100 g body weight-1, was recorded in the 14-day group and was significantly higher than the corresponding control value (0.34 +/- 0.07 ml.min-1 x 100 g body weight-1) (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Localization of fibril/microfibril and basement membrane collagens in diabetic glomerulosclerosis in type 2 diabetes.

Collagen is one of the major components of the extracellular matrices of the kidney. Basement membrane collagen, type IV collagen, is the major component in normal glomeruli. Fibril and interstitial collagen such as type III collagen, type V collagen, and type VI collagen are minor components of glomerular extracellular matrices and are localized mainly in the interstitium. Diabetic glomerulosclerosis is characterized by the expansion of the glomerular mesangial matrix as well as by thickening of the glomerular basement membrane. In order to clarify the roles of these various types of collagen in the development of diabetic glomerulosclerosis, immunohistochemical studies were performed in kidney specimens from patients with Type 2 diabetes. Early glomerulosclerosis is characterized by expansion of mesangial matrix with basement membrane collagen. However, in later stages glomerulosclerosis is characterized by an increase in the minor collagen components, such as type V and type VI collagen or collagens not normally present, such as type III collagen. Mesangial cells are known to synthesize all these types of collagen. In diabetes, phenotypic change in mesangial cells might produce excess amounts of fibril and interstitial collagen such as type III, type V, and type VI collagen, thus, leading to glomerulosclerosis.

Aged↗
PubMed1994

Ultrastructural localization of the three major basement membrane components--type IV collagen, heparan sulfate proteoglycan and laminin--in human membranous glomerulonephritis.

Membranous glomerulonephritis (MN) is characterized by the presence of subepithelial immune complexes and thickening of the glomerular basement membrane (GBM). Immune complexes are recognized as subepithelial electron-dense deposits (EDDs) by electron microscopy. We used immunogold electron microscopy to detect the GBM components--type IV collagen, heparan sulfate proteoglycan (HS-PG) and laminin--in thickened GBM, and studied the relationship between immune complexes and these GBM components. We demonstrate that the three major basement membrane components are distributed throughout the newly synthesized GBM. These findings suggest that type IV collagen, HS-PG, and laminin together comprise the spike-like structures and the newly synthesized GBM-like matrix in the thickened GBM of idiopathic MN and membranous lupus nephritis. The newly constructed matrix in the GBM appears to be composed of nearly normal GBM. In type IV collagen, the alpha 1-chain was rarely present on the newly synthesized basement membrane in the lamina rara externa, while alpha 3-chain was present on the subepithelial newly synthesized basement membrane. HS-PG was found within EDDs in membranous lupus nephritis. This suggests that anti-DNA antibody may cross-react with the HS-PG component of the GBM and thus form a subepithelial immune complex.

Adult↗
PubMed1994

Mesangial matrices act as mesangial channels to the juxtaglomerular zone. Tracer and high-resolution scanning electron-microscopic study.

The mesangium is centrally located in the glomerulus and plays an important role in the microcirculation within the glomerulus. In order to reveal the role of the mesangial matrix in the microcirculation, the movement of native anionic ferritin into the juxtaglomerular region was tracked following the intravenous injection of ferritin into rats. The three-dimensional ultrastructures of the mesangial matrix and juxtaglomerular apparatus were studied by conventional scanning and high-resolution scanning electron microscopy after removal of the cellular components. Many ferritin particles were observed from the glomerular capillary to the mesangial matrix, in the mesangial matrix of the juxtaglomerular apparatus and in the tubular lumen of the macula densa after the injection of ferritin. Secretion of macromolecules from the distal tubules seems to be one of the exits from the juxtaglomerular zone. The mesangial matrix was continuous from the vascular pole to the periphery like a branching tree. The intraglomerular mesangial matrix was continuous to the extraglomerular mesangial matrix in the juxtaglomerular region. The mesangial matrix appeared to consist of a polygonal meshwork structure of thin fibrils and pores with high-resolution scanning electron microscopy. The thinnest fiber was approximately 6-nm wide, and the pore size was averaged 20 nm in diameter. We were able to demonstrate the meshwork structure of the mesangial matrix, thus giving the morphological basis of the mesangial matrix to serve as mesangial pathway from the intraglomerular to the extraglomerular mesangial matrix.

Animals↗
PubMed1994

Meshwork structures in bovine glomerular and tubular basement membrane as revealed by ultra-high-resolution scanning electron microscopy.

We examined the ultrastructure of the bovine glomerular basement membrane (GBM) and tubular basement membrane (TBM) using ultra-high-resolution scanning electron microscopy after conductive staining without metal coating. Purified basement membranes (BMs) were obtained by sonication and acellular BMs by detergent treatments. Purified GBMs (PGBMs) and acellular GBMs (AGBMs) showed similar meshwork structures composed of regular round or oval pores and branching strands. Pore diameters were 10.2 +/- 2.4 nm (mean +/- SD) in PGBMs and 9.8 +/- 3.1 nm in AGBMs. Purified TBMs (PTBMs) and acellular TBMs (ATBMs) exhibited heterogeneous meshwork structures in which compact meshes in the cristae were combined with coarse meshes in the invaginations on the epithelial surfaces. Pore diameters were 12.6 +/- 5.2 nm in PTBMs and 11.4 +/- 4.0 nm in ATBMs which were significantly larger than those in GBMs. The width of the strands ranged from 3 to 15 nm in all BMs. A 4 M guanidine hydrochloride extraction of the acellular BMs revealed large polygonal networks in the invaginations of the TBM and twisted strands which were considered to be type IV collagen fibrils. Ultra-high-resolution scanning electron microscopy and conductive staining were useful for the study of three-dimensional architectures of BMs and revealed heterogeneous meshwork structures in the GBM and TBM which were probably caused by a different ratio of the major components.

Animals↗
PubMed1994

Nephrotic tunnels in glomerular basement membrane as revealed by a new electron microscopic method.

To clarify the ultrastructure in situ of the normal human glomerular basement membrane and ultrastructural changes of the glomerular basement membrane in patients with nephrotic syndrome, specimens of normal renal tissue and specimens from patients with membranous nephropathy, lupus nephritis, minimal change nephrotic syndrome, diabetic nephropathy, and Alport's syndrome were obtained. Specimens were examined by transmission electron microscopy by the newly devised "tissue negative staining method." Normal glomerular basement membrane showed a three-dimensional lattice-like meshwork of fibrils measuring 1.9 +/- 0.4 nm in diameter that formed numerous uniform, round, oval, or polygonal pores 2.5 +/- 0.4 nm in short diameter and 2.8 +/- 0.5 nm in long dimension. The nephrotic glomerular basement membrane revealed varying degrees of ultrastructural defects, the most prominent being tunnels and cavities. Tortuous tunnels measuring approximately 15 to 50 nm in diameter penetrated the entire glomerular basement membrane. Cavities of various shapes measuring 15 to 200 nm in diameter were diffusely scattered in the glomerular basement membrane and occasionally aggregated to form a honeycomb structure that occupied the whole thickness of the glomerular basement membrane. These defects appeared to be the pathway for protein leakage.

Diabetic Nephropathies↗
PubMed1994

Impaired interleukin-8-dependent chemotaxis by synovial fluid polymorphonuclear leukocytes in rheumatoid arthritis.

The accumulation of polymorphonuclear leukocytes (PMN) in synovial fluid is a common feature of rheumatoid arthritis (RA). We studied the chemotactic response of PMN obtained from the synovial fluid and from the peripheral blood of patients with RA using a modified Boyden's method, in which interleukin-8 (IL-8) or N-formyl-methionyl-leucyl-phenylalanine (FMLP) was used as a chemotactic agent. The IL-8-induced response of peripheral blood PMN from 15 patients with RA did not differ from that of 15 healthy controls. A decreased chemotactic response to IL-8 was, however, observed in PMN from the synovial fluid of 12 patients with RA compared with peripheral blood cells of the same individual. This defective chemotactic ability of PMN was inversely correlated with the number of infiltrating cells in the synovial fluid. We also obtained similar results with FMLP. These results indicate that the chemotactic ability of PMN may be reduced after migrating to the synovial fluid.

Adult↗
PubMed1994

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↗
PubMed1994

Clinical significance of necrosis in lupus nephritis.

The significance of necrosis (karyorrhexis), among the most characteristic findings in lupus nephritis, was evaluated by studying the correlation between the existence of necrosis in renal biopsy specimens and laboratory findings. The subjects were 54 patients with diffuse proliferative lupus nephritis and 6 patients with focal proliferative lupus nephritis selected from 143 patients with lupus nephritis. We also compared the clinical course of oral prednisolone and intravenous methylprednisolone pulse therapies after steroid administration. Compared with the non-necrosis group, the necrosis group had significantly lower CH50 levels and more proteinuria. Patients with necrosis were effectively treated with repeated pulse therapy judging by immunological activity and the decrease in proteinuria at an early stage, but responded poorly to oral steroid therapy. As the presence of necrosis in cases of lupus nephritis means high immunological activity of the lesion and there is responsiveness to a large dose of steroids, extensive immunosuppressive therapy including methylprednisolone pulse therapy should be applied to these patients.

Administration, Oral↗
PubMed1994

Expression of mRNA's of cytokines and growth factors in experimental glomerulonephritis.

A variety of cytokines and growth factors have been recently shown to modulate the growth of mesangial cells and the synthesis of the mesangial matrix. We examined chronological change of mRNA expression of interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), transforming growth factor beta 1 (TGF-beta 1), and the platelet-derived growth factor (PDGF)-B chain in glomeruli of nephrotoxic serum nephritis using reverse transcription and the polymerase chain reaction (RT-PCR) method. Expression of TNF-alpha mRNA increased immediately after induction of nephrotoxic serum nephritis. Levels of IL-1 beta and PDGF-B chain mRNAs increased at 24 hr and remained elevated for 4 weeks. TGF-beta 1 mRNA expression increased significantly at 24 hr, peaking at 2 weeks. The chronological changes of these cytokines and growth factors were associated with two phases of inflammation in this model. Among them, expression of PDGF-B chain mRNA preceded mesangial proliferation and expression of TGF-beta 1 preceded accumulation of mesangial matrix, indicating that these two growth factors contributed to these histological alterations.

Animals↗
PubMed1994

[A case of scleroderma renal crisis with acute interstitial pneumonia, microangiopathic hemolytic anemia and refractory thrombocytopenia].

A 46-year-old woman who noticed tightness of the skin in September, 1993, was admitted to a local hospital due to hypertension, congestive heart failure and renal dysfunction on the 2nd of November. After admission, renal function deteriorated progressively. A diagnosis of scleroderma renal crisis (SRC) was suspected from her skin biopsy and clinical course. She was referred to our hospital for further evaluation and maintenance of hemodialysis. Her blood pressure was kept normal by anti-hypertensive drugs including cilazapril. Acute interstitial pneumonia, microangiopathic hemolytic anemia and thrombocytopenia appeared during her clinical course. Corticosteroid therapy was effective for acute interstitial pneumonia, but in-effective for thrombocytopenia. Plasma exchange was not effective for thrombocytopenia, which was successfully treated with intravenous gamma-globulin therapy. She died of cytomegaloviral encephalitis, which might have resulted from immunodeficiency caused by prolonged corticosteroid therapy and uremia. Complications other than SRC might have appeared during the clinical course based on the immune disorder of progressive systemic sclerosis itself. In order to improve the prognosis of patients with SRC such complications should be detected promptly and treated correctly.

Acute Disease↗
PubMed1994

In vitro micro-autoradiography of atrial natriuretic peptide in biopsy specimens from patients with renal diseases.

We investigated the localization and density of atrial natriuretic peptide (ANP) receptors in human renal biopsy specimens by using in vitro micro-autoradiography (ARG) of [125I]-alpha-human (1-28) ANP. In a preliminary study, we measured the effect of storing tissue samples on ANP binding, using in vitro micro-ARG of Wistar rat kidney under optimal conditions. Duration of the preservation period did not affect ANP binding to renal tissue until samples had been stored at -30 degrees C for two years. A total of 11 human renal tissues were used to assay binding of ANP-ARG, including normal tissue obtained after nephrectomy because of renal cancer. ANP binding occurred predominantly within the glomerulus and, to a lesser extent, in the tubular region both in rat kidney sections and in human renal biopsy specimens. The density of ANP binding, calculated by counting grains in fixed areas, was compared with normal and pathological tissues. The density of grains tended to decrease in patients with renal dysfunction and hypertension except for one case of IgA nephropathy with normal renal function and blood pressure. The density of grains increased in a patient with nephrogenic diabetes insipidus. In the present study, we have established a method that uses in vitro micro-ARG for assessing ANP binding in human biopsy specimens.

Animals↗
PubMed1994

[Effect of heparin and low-molecular-weight heparin on proliferative glomerulonephritis].

Effect of heparin and low-molecular-weight heparin (LMWH) were evaluated on 15 patients with proliferative glomerulonephritis with various degrees of sclerosing legion. Five cases were subcutaneously administered with 7000 to 11000 units of heparin for 4 weeks. Ten cases were administered with 60 unit/kg of LMWH by drip infusion for 4 weeks. Eleven cases were treated with prednisolone and all cases were treated with anti-platelet agent as well. Urinary protein excretion reduced from 3.0 +/- 1.8 to 1.8 +/- 0.6 g/day in the heparin-treated group and from 2.4 +/- 1.9 to 1.8 +/- 1.4 g/day in the LMWH-treated group, respectively. There were no remarkable changes in the renal functions of both groups. In one case, both heparin and LMWH brought about reduction of proteinuria. Therefore, LMWH reduced urinary protein excretion by the same mechanism as heparin. The LMWH has an advantage over heparin in that the former has less risk of causing bleeding. We conclude that heparin and LMWH reduce proteinuria in some patients with proliferative glomerulonephritis. The LMWH is beneficial in the treatment of proliferative glomerulonephritis with a sclerosing lesion.

Adolescent↗
PubMed1994

Treatment with cilazapril, angiotensin-converting enzyme inhibitor, changes the affinity of arginine vasopressin receptor in the kidney of the spontaneously hypertensive rat.

To elucidate the interaction between the renin-angiotensin system and arginine vasopressin (AVP), we investigated the change in the renal AVP receptor in the spontaneously hypertensive rat (SHR) treated with an angiotensin-converting enzyme (ACE) inhibitor, cilazapril. SHR (age 15 weeks) were given oral cilazapril 10 mg/kg body weight daily for 25 days (ACEI group). Systolic blood pressure was significantly decreased in the ACEI group as compared with the untreated SHRs (control group) after day 2. Urine volume in the ACEI group was 3- to 5-fold higher than that in the control group. Under these conditions, the renal AVP receptor was studied using the radiolabeled receptor assay (RRA) of [3H]-AVP from renal medulla membrane fractions. The serum concentrations of sodium, potassium, chloride, urea nitrogen and creatinine were not significantly different between the two groups. The plasma concentration of AVP in the ACEI group was higher than that in the control group. The dissociation constant (Kd) in the ACEI group was significantly lower than that in the control, although there was no significant change of maximum binding capacity (Bmax) between the two groups. We previously reported that the number of renal AVP receptors decreased in rats with diabetes insipidus which were treated with lithium, suggesting that the change in the AVP receptor is a primary cause of polyuric state induced by lithium. In the present study, the diuretic state and the decrease in blood pressure induced by cilazapril resulted in a marked decrease in the Kd of the renal AVP receptor and an increase in the plasma AVP level. It is suggested that plasma AVP and renal AVP receptors in SHR responded to the diuretic state induced by cilazapril by increasing the secretion and renal receptor affinity. We conclude that the AVP system plays an important role in the regulation of the fluid balance under diuretic conditions caused by ACE inhibitor treatment.

Animals↗