Biomedical subjects

Takehiro Ohara

Publications and source records attributed to Takehiro Ohara.

10 recordsLinked to original sources

PubMed2005

Significance of subclinical rejection in early renal allograft biopsies for chronic allograft dysfunction.

To determine the significance of early subclinical rejection of renal allografts, we reviewed 127 biopsy specimens obtained soon after transplantation. Histological finding was categorized according to a modification of the Banff scheme as: acute rejection (AR), borderline changes (BL); non-specific inflammatory changes, (NI) and no rejection (NR). Subclinical rejection was defined as AR, BL or NI. Patients with BL or NI were divided into two groups; one was treated with high-dose methylprednisolone (MP), the other remained untreated. Freedom from chronic allograft dysfunction (defined as non-doubling of serum creatinine 5 yr after transplantation) was significantly more frequent in the NR group (89%) than in the BL (70%) and AR (64%) groups. At 1 yr after transplantation, mean serum creatinine had increased significantly only in the untreated group (p < 0.05), and re-biopsy showed that interstitial fibrosis had developed to a significantly greater extent in the untreated group than in the treated group (p < 0.01). Subclinical rejection in the early protocol biopsies correlated closely with subsequent allograft dysfunction. High-dose MP treatment for early subclinical rejection may be effective in suppressing the development of interstitial fibrosis at 1 yr after transplantation.

Adult↗

PubMed2005

Post-transplant early recurrent proteinuria in patients with focal glomerulosclerosis--angiotensin II immunostaining and treatment outcome.

We reviewed the transplantation data and results of histopathological studies with additional angiotensin II (AII) immunostaining of renal graft biopsies of nine cases (10 grafts) with recurrent proteinuria and three controls without recurrent proteinuria that received renal transplantation for primary focal segmental glomerulosclerosis (FSGS) between 1986 and 2002. Recurrent FSGS was confirmed in six grafts from nine cases by light microscopy. In cases with recurrent proteinuria, loss of graft function was noted in all six renal grafts received between 1986 and early 1992 but in none of four grafts received between late 1992 and 2002. Two of four patients of the late group but none of those of the early group received angiotensin converting enzyme (ACEI) or angiotensin II receptor blocker (ARB) with plasma exchange (PE). In control cases without proteinuria, AII immunostaining was detected in tubules but not in glomeruli in 1-hour biopsies as well as later on. In cases with recurrent proteinuria, AII immunostaining was detected in both tubules and glomeruli, although glomerular AII staining was not observed in 1-hour biopsies. Our results suggest that effective treatment of post-transplantation recurrent FSGS requires ACEI or ARB with PE in the absence of another etiology.

Adolescent↗

PubMed2005

A prospective trial of steroid withdrawal after renal transplantation treated with cyclosporine and mizoribine in children: results obtained between 1990 and 2003.

A prospective trial of adrenocorticostertoid (steroid) withdrawal after pediatric renal transplantation was begun in 1990. Ninety-four pediatric renal transplant recipients were enrolled in our multicenter study. Immunosuppressive therapy with cyclosporine (CyA), methylprednisolone (MPL), and mizoribine (MZ) was started after transplantation. MPL was reduced to administration on alternate days in 69 patients (73.4%) and was withdrawn in 27 patients (28.7%). Rejection episodes occurred in nine patients (33.3%) after withdrawal of MPL. It occurred within 3 months after withdrawal of MPL in two patients and more than 6 months in the others. Among them, two patients lost the grafts. Thirteen-year patient survival rate and graft survival rate were 94.6 and 83.1%, respectively. Forty-four of the 94 patients reached their final height. Mean final height was 155.0 cm in males and 146.3 cm in females and their height standard deviation score was -2.6 s.d., the same as that at the time of transplantation. Management of growth retardation before transplantation and further reduction in the steroid dose after transplantation will increase the final height of children with chronic renal failure.

Adolescent↗

PubMed2005

Clinical course of congenital nephrotic syndrome and Denys-Drash syndrome in Japan.

BACKGROUND: The prognosis of Japanese patients with congenital nephrotic syndrome (CNS) and Denys-Drash syndrome (DDS) is not clear. METHODS: Five patients with CNS and four patients with DDS, which causes secondary CNS, were studied retrospectively. RESULTS: Seven patients were sporadic and two DDS patients were identical twins. Five CNS patients presented with edema within 3 months of birth. In four DDS patients, edema was not noted and end-stage renal disease developed between 7 months and 6 years of age. Of these five CNS patients, one patient had cerebral thrombosis and cytomegalovirus pneumonia at the onset and another patient died during dialysis. Frequent intravenous albumin administration required, growth and development during infancy were varied. Of the nine patients with CNS and DDS, seven received renal transplantation and were alive with functioning grafts at the last follow up. Catch-up growth was observed in five patients after transplantation. Five school-aged patients attended school and received adequate grades and two adults worked full-time. Of the DDS patients, dysuria due to hypospadias persisted in one patient and treatment for hypogonadism was needed in one patient. CONCLUSIONS: CNS and DDS were diagnosed early after onset and adequate treatment was started. Growth and development after renal transplantation were relatively good. Thrombotic episodes or severe infection in CNS patients was difficult to manage and complications resulting from DDS affected the quality of life.

Denys-Drash Syndrome↗

PubMed2004

Activation of nuclear factor-kappa B and macrophage invasion in cyclosporin A-and tacrolimus-treated renal transplants.

This retrospective study was designed to compare the efficacy of cyclosporin A (CyA) and tacrolimus (FK506) on chronic rejection (CR) associated with nuclear factor-kappa B (NF-kappaB) activation and macrophage invasion. Non-episodic day 50 protocol renal biopsy was performed in 63 consecutive patients with renal transplants from living donors, treated with either CyA or FK506. Southwestern histochemistry for NF-kappaB, immunostaining for CD68, and Banff classification were performed, and these findings were compared with outcome over 34 +/- 13 months. Compared with specimens from FK506-treated patients (n = 20), specimens from CyA-treated patients (n = 43) showed a significant increase in tubulointerstitial CD68-positive cells (1.5 +/- 0.9 vs. 0.9 +/- 0.8, p < 0.01), although no significant differences were observed in NF-kappaB activation. Specimens with Banff acute rejection (AR) grade > or = 1A (n = 20) showed increased macrophages (p < 0.01) compared with specimens with AR < 1A (n = 43). Specimens from patients with clinical AR prior to day 50 biopsy (n = 23) also showed increased macrophage invasion (p < 0.01) compared with specimens from patients without prior clinical AR (n = 40). The cumulative well-functioning (serum creatinine < 1.5 mg/dL) graft survival rate was significantly lower in patients with increased tubulointerstitial CD68-positive cells (n = 63, p < 0.05). Our findings suggest that tacrolimus is more effective than CyA against CR with respect to macrophage invasion and AR.

Adult↗

PubMed2004

Estimation of damaged tubular epithelium in renal allografts by determination of vimentin expression.

BACKGROUND: Various invasive and non-invasive methods have been investigated for their prognostic value in predicting the outcome of renal allografts. In the present study, vimentin expression in tubular epithelial cells (TEC) was determined by the immunohistochemical examination of biopsy specimens and the prognostic value of this method was assessed. METHODS: Ninety-two renal transplant recipients were recruited for the present study. Protocol biopsy of the renal graft was performed 1, 3 and 5 years after transplantation in each case. All biopsy specimens were treated with conventional stains and immunostained with an antivimentin antibody. The correlation between vimentin expression and glomerular filtration rate (GFR) and the association between vimentin expression and histopathological findings were determined. RESULTS: Vimentin was localized in TEC adjacent to interstitial lesions with lymphocyte infiltration and also in TEC with tubulitis or in atrophic tubules. Vimentin positivity significantly correlated with GFR and both vimentin positivity and GFR were significantly associated with the extent of chronic allograft nephropathy, but not with acute rejection. Additionally, vimentin expression and GFR 3 and 5 years after transplantation were higher in cases where graft loss occurred between 5 and 7 years after transplantation compared with graft survival cases. CONCLUSIONS: These results suggest that immunohistochemistry using antivimentin antibodies on protocol biopsy specimens is useful for the detection of injured TEC and as a predictor of allograft outcome.

Adult↗

PubMed2004

Clinical outcome and accommodation in ABO incompatible kidney transplantation.

We performed 84 ABO-incompatible kidney transplants at Toho University since 1989, with plasmapheresis and exchange replacing AB blood group plasma as pre-conditioning to reduce anti-donor blood group antibodies. Our current immunosuppression protocol consists of basiliximab, MMF, steroid, and cyclosporine or tacrolimus, including splenectomy. Overall patient/ graft survival rates (n=84) were 95/93 at one year, 94/92 at 3 years, 87/80 at 5 years, 87/75 at 7 years, and 83/67 at 10 years. The outcomes are similar to those of ABO-compatible living donor transplants. We have achieved 100% graft and patient survival rates (n=48) for the 7 years since January 1997. Our findings suggest that post-conditioning is not necessary to control titers of anti-donor blood group antibodies or to overcome acute humoral rejection. Infection control is critical in achieving good outcomes in ABO-incompatible transplants. We found that only anti-donor blood group antibodies in blood group O recipients of ABO-incompatible kidneys were specifically suppressed one year after transplantation. This appeared to be a type of accommodation in which there was no immunological response despite the co-existence of donor antigen and antibody, and might have been caused by down-regulation of B cells to produce anti-donor antibody.

ABO Blood-Group System↗

PubMed2003

Living related kidney transplantation in a patient with autosomal-recessive Alport syndrome.

We discuss a patient with Alport syndrome who received a renal transplant from a donor with thin basement membrane disease. A 30-year-old woman, diagnosed with Alport syndrome on the basis of sensorineural hearing loss, characteristic renal biopsy findings and a family history of microhaematuria, entered chronic haemodialysis therapy. She then received a renal transplant donated from her father, who had sensorineural hearing loss and persistent microhaematuria. On the day of renal transplantation, a 1-h graft biopsy after reperfusion showed thin basement membrane disease. We re-tested the patient's native kidney biopsy specimen by immunohistochemical staining using alpha-chain-specific collagen type IV monoclonal antibodies. There was no expression of collagen type IV alpha3-, alpha4- and alpha5-chain on glomerular basement membrane, but positive staining of alpha5-chain on Bowman's capsular basement membrane was noted. A diagnosis of autosomal-recessive Alport syndrome was made. We concluded that this family might display different phenotypic expressions of the same genotype: one suffered end-stage renal disease and the other thin basement membrane disease.

Adult↗

PubMed2003

ABO incompatible kidney transplantation --immunological aspect-.

ABO incompatible kidney transplantation (ABOINCKT) has been developed in Japan because of the shortage of cadaveric donors. We have performed 76 living-donor ABOINCKT in our center. Donor blood type antibody was removed by immunoadsorption or plasmapheresis and exchange. Immunosuppression consisted of cyclosporine or tacrolimus, steroid, and cyclophosphamide or azathioprine or mycophenolate mofetil and, recently, basiliximab. Splenectomy was routinely performed during the transplantation surgery. Donor blood type antigen was strongly expressed on the vascular endothelium at all time points and in all conditions posttransplantation. Red blood cell agglutination reaction (RBAR) was positive only in renal tissues from a patient with delayed hyperacute rejection. Donor specific antibody suppression was observed in 18 ABOINCKT recipients with blood type O from a donor with blood type A1 or B. ADCC activity was detected after pre-treatment. Acute humoral rejection in ABOINCKT can result from ADCC, as well as by antigen-antibody reaction. Five year graft and patient survival rates were 75% and 64% in 37 ABOINCKT recipients from June 1989 through December 1996, however they have been 100% in 39 ABOINCKT recipients since January 1997. Accommodation has been produced in ABOINCKT with the co-existence of blood type antigen and antibody. Currently, ABOINCKT is an alternative which should be considered, particularly for blood type O patients with extended waits for cadaveric transplantation and for pediatric patients.

ABO Blood-Group System↗

PubMed2002

[Not Available].

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Journal Article↗