Biomedical subjects

N Akano

Publications and source records attributed to N Akano.

At least 19 recordsLinked to original sources

PubMed1996

Proto-oncogene expression in human glomerular diseases.

The expression of the protein products and mRNA of c-fos, c-myc, p53, and c-raf was examined in normal renal tissues and biopsy specimens from 73 patients with various glomerular diseases. Immunofluorescent staining showed that there were cell nuclei stained for c-Fos, c-Myc, and p53, and cytoplasm positive for c-Raf, in the glomeruli of patients with proliferative types of glomerulonephritis, including IgA nephritis and lupus nephritis, and in patients with focal glomerular sclerosis. Glomerular expression of c-fos and c-myc mRNA was detected by in situ hybridization. The number of proto-oncogene-positive glomerular cells was significantly higher in lupus nephritis, IgA nephritis, and focal segmental sclerosis, as compared with minimal change nephrotic syndrome and normal specimens. In IgA nephritis, the population of glomerular cells positive for c-Fos and c-Myc and the grade of c-Raf immunoreactivity were significantly correlated with the proportion of proliferating cell nuclear antigen (PCNA)-positive glomerular cells, with histological grading of mesangial hypercellularity and matrix increase, and with the magnitude of proteinuria. These data indicate that proto-oncogene expression is associated with mesangial proliferation and matrix expansion in proliferative types of glomerulonephritis and in focal glomerular sclerosis.

Cell Nucleus↗

PubMed1994

Cellular localization of inflammatory cytokines in human glomerulonephritis.

We evaluated the expression of inflammatory cytokines in renal tissues obtained from 45 patients with several types of glomerulonephritis. Immunofluorescence studies with specific antibodies to interleukin (IL)-1 alpha, IL-1 beta, IL-6, tumour necrosis factor (TNF)-alpha, and TNF-beta showed intense cytoplasmic staining in the glomeruli and interstitium. Cells positive for these cytokines were found frequently in tissue from patients with lupus nephritis (WHO Class IV) and membranoproliferative glomerulonephritis, and, to a lesser extent, in tissue from patients with mesangial proliferative glomerulonephritis, Henoch-Schönlein purpura nephritis, and minimal change nephrotic syndrome. Most of these cells were dual-stained with a monoclonal antibody to monocytes-macrophages. In situ hybridization for cytokine mRNA, combined with immunoperoxidase staining for monocytes-macrophages, detected IL-1 alpha, IL-6, and TNF-alpha mRNA in monocytes-macrophages infiltrating the glomeruli and interstitium. Occasionally, there was weak or moderate immunostaining for IL-1 alpha, IL-6, and TNF-alpha in the glomerular mesangial and epithelial cells, but in situ hybridization signals were rarely found in these loci. These findings suggest that infiltrating monocytes-macrophages, rather than resident glomerular cells, are the major source of inflammatory cytokines in human glomerulonephritis.

Glomerulonephritis↗

PubMed1994

Combined therapy in children and adolescents with IgA nephropathy.

We retrospectively evaluated renal outcome in a total of 38 children and adolescents with IgA nephropathy who were selected for 6-month therapy for clinical (proteinuria > 1 g/m2/24 hour) and pathologic (mesangial proliferation, crescent formation, and tubulo-interstitial changes) features suggestive of progressive renal failure. Seventeen patients (group A) were treated with a combination of prednisolone, cyclophosphamide and dipyridamole, and the remaining patients (21; group B) were treated with the same drugs plus warfarin. All the patients were followed-up for more than 2 years (range 2-10 years, mean 4.8). In both groups, the mean urinary protein excretion value was significantly reduced after the therapy, compared with that at entry into the therapy. The significant reduction continued for up to 6 years in group A and up to 5 years in group B. Creatinine clearance was stable until 5-6 years after the trial in both groups, but 4 patients progressed to end-stage renal failure after that period. Post-therapy biopsy was performed in 14 patients, and was compared with the pre-therapy biopsy. The activity score had improved in both groups, but the chronicity score did not. These results indicate that there was a temporary effect and limited benefit with this treatment of combined drugs for children and adolescents with IgA nephropathy. The additive effect of warfarin was not substantiated.

Adolescent↗

PubMed1993

Immunotactoid glomerulopathy in a child with Down syndrome.

A 9-year-old girl with Down (21-trisomy) syndrome was found to have proteinuria and microscopic haematuria at age 6 years. Proteinuria gradually increased during the next 3 years, although blood pressure and renal function remained normal. The patient exhibited no underlying systemic diseases, monoclonal gammopathy, cryoglobulinaemia or histological evidence of plasmacytoma. A percutaneous renal biopsy revealed immunotactoid glomerulopathy (fibrillary glomerulonephritis) characterized by thickening of the glomerular basement membrane, diffuse mesangial expansion and various-sized acid-Schiff-positive nodules that were intensely positive for IgG, light chains (kappa and lambda) and complement components (C3, C4, C1q) along the glomerular capillaries in the mesangium. Congo red dye and amyloid thioflavine T staining were negative. Fibrils (15-17 nm in diameter--larger than amyloid fibrils) were present in the mesangial area and within the glomerular basement membrane. We are not aware of a previous report of immunotactoid glomerulopathy and a patient with chromosomal abnormalities.

Child↗

PubMed1993

Immunohistochemical localization of C3d fragment of complement and S-protein (vitronectin) in normal and diseased human kidneys: association with the C5b-9 complex and vitronectin receptor.

The localization of C3d, a fragment produced by C3 activation and S-protein (vitronectin), a regulatory factor of C5b-9, was studied immunohistochemically in normal human kidney and renal biopsies from patients with several types of glomerulonephritis. Immunofluorescent staining of the normal kidneys showed that C3d was present along the glomerular basement membrane (GBM), tubular basement membrane (TBM) and arterioles, and that S-protein was present in the GBM, mesangium, TBM, and arterioles. Immunoelectron microscopy of isolated basement membranes showed that C3d was localized exclusively on the epithelial side of the GBM, and that S-protein was present along both the epithelial and endothelial sides. In nephritic tissues, glomerular staining of C3d, C5b-9, and S-protein was increased when compared with that in normal tissues. S-protein, frequently co-localized with C3d and C5b-9 neoantigen, was intensely positive in the immune deposits of glomerular capillaries and the mesangial area, overlapping the background staining of GBM and mesangial matrix. S-protein and its receptor were occasionally co-localized in the glomeruli. These findings indicate that C3d and S-protein are normally present in the glomeruli. Co-staining of C3d, C5b-9 neoantigen, and S-protein within the immune deposits of nephritic kidneys suggests in situ binding of S-protein to locally-formed C5b-9 complex, or merely co-distribution of S-protein with the complex, rather than trapping of large molecular SC5b-9 complex from the circulation.

Complement C3d↗

PubMed1993

[Focal glomerular sclerosis in a sibling].

We described here one sibling with focal glomerular sclerosis. Proteinuria was noticed at the age of five in brother and four in sister. Both of them developed nephrotic syndrome shortly after the discovery of proteinuria. The nephrotic syndrome was resistant to corticosteroid, immunosuppressive agents or the combination of these drugs. Percutaneous renal biopsy in them revealed morphological and immunohistological features compatible to focal glomerular sclerosis. HLA typing in HLA-A, B, C and DR loci was identical to both. This observation suggests that genetic factors is associated with the pathogenesis of focal glomerular sclerosis.

Adolescent↗

PubMed1992

IgA nephropathy in patients with congenital C9 deficiency.

The clinical, histologic, and immunopathological findings of three young Japanese males with congenital C9 deficiency and primary IgA nephropathy are reported. The C9 deficiency was discovered either through mass complement screening, or when low hemolytic activity for CH50 and normal C3 levels were detected in plasma. Hematuria and proteinuria were detected at the age of 8 or 9 years as a result of annual urinary screening tests for school children. Renal biopsy showed focal and segmental mesangial proliferation with small epithelial crescents in one patient, and mild, diffuse mesangial proliferation in two. IgA and C3 were deposited predominantly in the mesangial area, and staining for C9 was negative in these patients. Electron microscopy revealed electron dense deposits predominantly in mesangial and paramesangial zones. Immunohistochemical staining in renal biopsy tissues from two patients showed mesangial staining for C5, C8, and S-protein, but staining for C5b-9 neoantigen was completely negative. These results show that the formation of C5b-9 complex is not essential for the induction of human IgA nephropathy, and also for the proliferation of mesangial and even parietal epithelial cells.

Child↗

PubMed1992

[A case of Bufferin induced acute interstitial nephritis--analysis of immune cells and cytokine].

This paper describes a case report of acute interstitial nephritis associated with Bufferin. A 15-year-old girl were referred to our hospital due to fever and renal dysfunction. Laboratory findings showed elevation of serum BUN and creatinine, and increased urinary beta 2-MG excreation. Light microscopic findings of her renal biopsy specimen revealed edema and numerous inflammatory cells in the interstitium, and minor alterations in glomeruli. The interstitial infiltrates consisted mainly of T cells and also monocytes/macrophages. Interstitial cells were labelled with antibodies to interleukin (IL)-1 and tumor necrose factor (TNF). Bufferin was positive by lymphocyte stimulation test. Thus, we considered that this drug was causative in this case. This observation suggests the participation of cell-mediated immune injury in drug induced acute interstitial nephritis.

Acute Disease↗

PubMed1991

Acute interstitial nephritis and uveitis syndrome: activated immune cell infiltration in the kidney.

Infiltrating cells were analysed in renal biopsy tissue obtained from a 15-year-old girl with acute interstitial nephritis and uveitis using monoclonal antibodies specific for mononuclear cell surface markers. The interstitial infiltrates consisted mainly of T cells and monocytes/macrophages. A considerable proportion of the infiltrating cells were identified by a monoclonal antibody against the interleukin-2 receptor, indicating that a majority of those immune cells are activated. This observation documents the participation of cell-mediated immune injury in interstitial nephritis associated with uveitis.

Acute Disease↗

PubMed1991

Transient massive proteinuria associated with Mycoplasma pneumoniae infection.

A 5-year-old girl presented with Mycoplasma pneumoniae infection, which was associated with eyelid edema and massive proteinuria. Her clinical manifestations were similar to those of nephrotic syndrome, except for the absence of hypoproteinemia. Light microscopy of renal biopsy tissue showed minor glomerular abnormalities, with no tubulointerstitial changes. Electron microscopy showed sparse fusion of the foot processes, regular nonthickened glomerular basement membrane, and no electron-dense deposits. Immunofluorescent staining of the glomeruli for immunoglobulins (IgG, IgA, IgM) and complement (C3, C4) was negative. Mycoplasma antigen was not detected by indirect immunofluorescence. These findings suggest a causal relationship between M pneumoniae infection and transient renal injury.

Child, Preschool↗

PubMed1990

Distribution of type I collagen in human kidney diseases in comparison with type III collagen.

The distribution of type I collagen in normal and diseased renal tissues was studied using immunofluorescence and immunoelectron microscopy, and was compared with that of type III collagen. In normal human kidneys, a monoclonal antibody against type I or type III collagen reacted with the renal interstitium, but not with the intra-glomerular structures. In various types of glomerulonephritis, immunofluorescent staining for type I collagen was positive in the fibrocellular and fibrous crescents, sclerosed glomeruli, and infrequently within the glomerular mesangium. In the crescents and sclerosed glomeruli, type I collagen was co-localized with type III collagen. The staining intensity of type I collagen in those areas was generally stronger than that in the interstitium. Mesangial staining for type I collagen was present within the glomeruli, particularly with a marked mesangial matrix increase, but was less in amount and frequency compared with type III collagen staining. These findings indicate that the fibrosclerotic process in damaged glomeruli is accompanied by the appearance of interstitial collagens, and that participation of type I collagen is prominent in crescent organization and global glomerular sclerosis, but is less frequent in mesangial expansion, compared with type III collagen.

Adolescent↗

PubMed1990

[Three cases of oligomeganephronia].

Three cases of bilateral renal hypoplasia with oligomeganephronia are reported. In all three patients urine abnormalities were pointed out by annual urine screening for school-children and they showed mild or moderate deterioration of renal function. One patient had repeated episodes of urinary tract infection, and bilateral vesico-ureteral reflux (grade III) was found by the voiding cystourethrography. Light microscopic findings of renal biopsy specimens were similar in three cases; significant hypertrophy of the glomerulus and tubulus; mild mesangial expansion, and interstitial changes. Further histological examination which was done in one case showed widespread foot process fusion, mesangial interposition and membrane-like structures by electron microscopy, and mesangial IgA deposition by immunofluorescence. Three was no alteration in immuno-staining pattern for basement membrane components, including type VI and V collagens, laminin and fibronectin, in the glomeruli.

Adolescent↗

PubMed1990

Identification and localization of epidermal growth factor and its receptor in the human glomerulus.

Radioimmunoassay for epidermal growth factor (EGF) was performed using the homogenates of glomeruli and tubular preparations obtained from normal human kidneys. EGF-immunoreactive material was 3- to 5-fold higher in the glomerular fractions than in the tubular fraction. By indirect immunofluorescence with a monoclonal antibody, EGF was positive in three of five normal human kidney tissues and in tissues of 24 of 33 patients with proliferative and nonproliferative types of glomerular diseases. Acid-urea treatment of tissue sections to unmask a hidden epitope of the EGF molecule disclosed EGF immunoreactivity in four more kidney specimens. EGF was localized along the glomerular capillary walls and was also present in the arterioles and small arteries. Staining with three monoclonal antibodies recognizing two different epitopes of EGF receptor (EGF-R) was positive in tissues of 2 normal subjects and 15 patients with glomerular diseases. EGF-R was found along the glomerular capillary walls, in peritubular capillaries, and within the epithelial cells of distal tubules and collecting ducts. Immunoelectron microscopy with colloidal gold staining showed that EGF and EGF-R were localized in the plasma membrane of glomerular endothelial cells. Immunofluorescence with or without acid-urea denaturation showed coexpression of EGF and EGF-R in glomeruli of 1 normal subject and 12 patients. This study demonstrated the presence of EGF and EGF-R in human glomeruli. There was no obvious difference in EGF and EGF-R expression in glomeruli derived from normal or diseased state.

Antibodies, Monoclonal↗

PubMed1989

Immunoelectron microscopic localization of membrane attack complex and hepatitis B e antigen in membranous nephropathy.

Immunoelectron microscopy was used to localize membrane attack complex (MAC) and hepatitis B e (HBe) antigen in renal tissue specimens from a total of 9 patients with membranous nephropathy (MN); 6 with MN associated with a hepatitis B virus (HBV) infection, 2 with idiopathic MN, and 1 with lupus nephritis. All the patients were proteinuric, and 2 patients were classified as stage I-II, 6 as stage II, and 1 as stage IV. MAC, along with IgG and C3, was distributed within the subepithelial electron dense deposits in all the stages. MAC was also stained in the striated membranous structures within the glomerular basement membrane and mesangial matrix of some patients. In HBV-associated MN, HBe antigen was localized in the subepithelial electron dense deposits of 5 patients, while it was absent from the subepithelial deposits in a patient that was sero-positive for hepatitis B s antigen but negative for HBe antigen. This patient also lacked MAC deposition in these loci. These results suggest that MAC is associated with the formation of subepithelial deposits and proteinuria in MN. In HBV-associated MN, HBe antigen-antibody immune complex makes up the subepithelial deposits and is likely to activate the terminal components of complement in situ.

Complement Membrane Attack Complex↗

PubMed1989

Glomerular localization of type III collagen in human kidney disease.

Kidney specimens taken from normal humans and patients with various renal diseases were examined by immunofluorescent and immunoelectron microscopy using a monoclonal antibody to the alpha 1 chain of type III collagen. Indirect immunofluorescent staining revealed that intraglomerular localization of type III collagen antigen in 41 of 66 patients, while it was absent from the glomeruli of normal human kidneys. Type III collagen was found within the mesangium of 22 patients with various types of renal diseases, and was distributed in a focal and segmental manner in most of the cases. Mesangial localization of the collagen correlated with the increase in the mesangial matrix. Type III collagen was also present in the vascular pole, crescents (particularly in the organizing phase) and sclerosed glomeruli. Immunoelectron microscopy using pre-embedding and post-embedding techniques confirmed the above observations. These findings indicate that type III collagen participates in mesangial expansion, crescent organization, and glomerulosclerosis.

Antibodies↗

PubMed1989

[Two brothers with reflux nephropathy].

This paper reports two brothers with reflux nephropathy. Patients who were 10-year-old and 12-year-old were referred to our hospital due to proteinuria and deterioration of renal function. Diagnosis of reflux nephropathy was made on drip infusion pyelography (DIP), voiding cystogram (VCG), and renal biopsy findings. The following findings were observed in renal tissues; focal and segmental sclerosis by light microscopy, IgM deposition by immunofluorescent microscopy, and glomerular basement membrane alterations and detachment of podocytes by electron microscopy. The HLA typing and analysis showed that both brothers and their mother possessed HLA-A9, which is reported to be closely associated with progression of primary reflux nephropathy to end-stage renal disease.

Child↗

PubMed1989

Monocyte infiltration and cross-linked fibrin deposition in IgA nephritis and Henoch-Schoenlein purpura nephritis.

To clarify the role of immune cell infiltration and fibrin deposition in glomerular injury, renal biopsy specimens taken from patients with primary IgA nephritis and Henoch-Schönlein purpura nephritis (HSPN) were evaluated using monoclonal antibodies specific to mononuclear cell surfaces and cross-linked fibrin (XFb). Monocytes/macrophages were the predominant cell type infiltrating glomeruli in IgA nephritis and HSPN. The intraglomerular monocyte population in both diseases was significantly higher than that in normals, mesangial proliferative (non-IgA) glomerulonephritis or minimal change nephrotic syndrome. In IgA nephritis, there was a clear correlation between glomerular monocyte accumulation and the degree of proteinuria. Although the monocyte influx tended to decline with time in HSPN, it remained unchanged in IgA nephritis. XFb deposition was found in the glomeruli of 27 out of 48 patients with IgA nephritis, and in 15 out of 20 with HSPN. The degree of XFb deposition in IgA nephritis correlated significantly with the degree of mesangial proliferation. These findings indicate a close relationship of monocyte/macrophage infiltration and XFb deposition with glomerular injury in IgA nephritis.

Adolescent↗

PubMed1988

Immunohistochemical study of the membrane attack complex of complement in IgA nephropathy.

The localization of the membrane attack complex of complement (MAC) was examined in the normal human kidneys and in biopsy specimens from patients with primary IgA nephropathy by immunofluorescent and immunoelectron microscopies. Immunofluorescent staining for MAC was significantly more intense than in the normal kidneys, and was observed in the mesangium and occasionally along the glomerular capillary walls of 22 of 30 patients with IgA nephropathy. By dual-staining, the MAC deposits were generally concordant with the deposits of IgA, C3, C5 and C9, or of IgG, when present. C1q or C4 was infrequently observed in the glomeruli. Immunoelectron microscopy revealed various staining patterns of glomerular MAC deposition; homogeneous fine-granular staining beneath the glomerular basement membrane (GBM) in the paramesangial zone, patchy staining within the mesangial electron dense deposits (EDD), and ring-shaped or ribbon-like staining, associated with the striated membrane structures (SMS), in the matrix of the mesangium, GBM and tubular basement membrane (TBM). This study suggests that the terminal complement system is activated, mainly by an alternative complement pathway mechanism, in the mesangium of IgA nephropathy, and is associated with the paramesangial lesion and EDD. MAC deposition in glomerular SMS may also result from in situ activation rather than trapping from the circulation. There was little correlation between glomerular MAC deposition and proteinuria or renal histology of patients with IgA nephropathy.

Complement Membrane Attack Complex↗