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Dive into the research topics where Hidetoshi Kanai is active.

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Featured researches published by Hidetoshi Kanai.


Arthritis & Rheumatism | 2001

Predominance of Th1 Immune Response in Diffuse Proliferative Lupus Nephritis

Kohsuke Masutani; Mitsuteru Akahoshi; Kazuhiko Tsuruya; Masanori Tokumoto; Toshiharu Ninomiya; Tsutomu Kohsaka; Kyoichi Fukuda; Hidetoshi Kanai; Hitoshi Nakashima; Takeshi Otsuka; Hideki Hirakata

OBJECTIVE Lupus nephritis, which shows various histologic patterns, is a serious complication of systemic lupus erythematosus (SLE). We previously demonstrated the importance of Thl cell-mediated immune response in patients with diffuse proliferative lupus nephritis (DPLN). The aim of this study was to examine the relationship between the peripheral blood Th1/Th2 balance and the intrarenal immune response. METHODS The Th1:Th2 ratio in peripheral blood was measured by intracellular staining for cytokines with flow cytometry. Immunohistochemical analysis of renal biopsy specimens was performed to clarify the characterization of local infiltrating cells in 3 groups of subjects: SLE patients with World Health Organization (WHO) class IV nephritis (DPLN) (group I; n = 13), SLE patients with WHO class V nephritis (group II; n = 9), and patients with minor glomerular lesions (group III; n = 7). In addition, the histologic activity index and chronicity index were evaluated and correlated with the Th1:Th2 ratio. RESULTS Immunohistochemical studies showed higher numbers of CD68+ macrophages, CD3 + T cells, and interferon-gamma-positive cells in group I than in groups II or III. Renal tissues from patients in group I also showed up-regulation of expression of osteopontin and CD40, with a small number of infiltrating T cells expressing interleukin-4. Overall, the Thl:Th2 ratio in group I patients (SLE with DPLN) was high and correlated significantly with the histologic activity index, but not with the chronicity index. CONCLUSION We have identified a predominance of Thl-type response in both peripheral and renal tissues of patients with DPLN, suggesting that the peripheral blood Thl:Th2 ratio directly reflects the local histopathologic findings. In patients with lupus nephritis, the peripheral blood Th1:Th2 ratio could be useful as a parameter that reflects the renal histologic activity or the strength of the local Thl response.


Journal of Hypertension | 2005

Increased renal resistive index in atherosclerosis and diabetic nephropathy assessed by Doppler sonography

Yuko Ohta; Koji Fujii; Hisatomi Arima; Kiyoshi Matsumura; Takuya Tsuchihashi; Masanori Tokumoto; Kazuhiko Tsuruya; Hidetoshi Kanai; Masanori Iwase; Hideki Hirakata; Mitsuo Iida

Objective The renal resistive index (RI) and pulsatility index (PI), measured using Doppler ultrasonography, reflect intrarenal vascular resistance. We evaluated the relationship between these indices and pulse wave velocity (PWV), a measure of arterial stiffness, which reflects atherosclerosis, and determined whether renal RI and PI differ depending on the underlying renal disease. Methods A total of 245 inpatients with or without renal impairment who underwent ultrasonographic assessment of the renal artery were enrolled in the study. Patients with renal artery stenosis or severe renal failure (serum creatinine ≥ 6 mg/dl) were excluded from the study. Results In univariate analysis, the RI and PI of the main renal arteries and the interlobar arteries were significantly correlated with PWV. Multivariate analyses showed that PWV was independently associated with the RI of the main renal arteries (P < 0.01, R2 = 0.256). Patients with a creatinine level less than 3 mg/dl were divided into a control group without renal diseases and three groups with different underlying renal diseases: diabetic nephropathy, chronic glomerulonephritis, and nephrosclerosis. The RI and PI of the main renal arteries and the interlobar arteries were significantly higher in patients with diabetic nephropathy than in the other three groups, even after adjusting for multiple variables, including creatinine clearance. Conclusion These results suggest that the increased RI of the renal arteries is associated with the severity of systemic atherosclerosis. Furthermore, the intrarenal vascular resistance differs depending on the underlying renal disease, and appears to increase to a greater extent in diabetic nephropathy.


Nephron Clinical Practice | 2004

Dialysis-Related Hypotension as a Cause of Progressive Frontal Lobe Atrophy in Chronic Hemodialysis Patients: A 3-Year Prospective Study

Tohru Mizumasa; Hideki Hirakata; Takahiro Yoshimitsu; Eriko Hirakata; Michiaki Kubo; Minoru Kashiwagi; Hiroshi Tanaka; Hidetoshi Kanai; Satoru Fujimi; Mitsuo Iida

Background/Aim: Brain atrophy is known to develop more rapidly in hemodialysis (HD) patients than other individuals. The present study was designed to examine the role of HD-related hypotension in brain atrophy in patients on chronic HD. Methods: By using magnetic resonance imaging, whole brain atrophy was assessed by the ventricular-brain ratio (VBR; ventricular area/whole brain area). Frontal brain atrophy was assessed by the frontal atrophy index (FAI; frontal brain area/intracranial frontal space). The number of lacunae was also counted. We studied 32 HD patients without symptomatic neurological abnormalities or diabetes mellitus: male/female ratio 19/13; mean age ± SD 53 ± 10 (range 28–77) years; mean HD duration ± SD 11 ± 6 (range 1–22) years. Magnetic resonance imagings were taken in 1995 and 1998. All dialysis-related hypotension episodes during the same period were identified from the medical records and counted. Results: The VBR ranged from 8.8 to 18.7% in 1995 (12.8 ± 2.2%) and was not different in 1998 (13.1 ± 2.7%). However, the VBR increased by more than 5% in 14 patients, and their HD duration of 13 ± 6 years was significantly longer than that of 18 patients with stable VBR (p < 0.05). The FAI in 1995 was 62.2 ± 4.2% (range 55.8–71.3%) and decreased significantly to 59.7 ± 4.7% (range 50.2–70.9%) in 1998 (p < 0.05). The change in FAI correlated significantly with both the total number of dialysis-related hypotension episodes (r = 0.45, p < 0.05) and the increase in number of lacunae (r = 0.42, p < 0.05). Conclusion: Our results suggest that dialysis-related hypotension plays a role in progressive frontal lobe atrophy in HD patients.


Clinical Nephrology | 2002

Diffuse proliferative glomerulonephritis after bone marrow transplantation.

Suehiro T; Masutani K; Yokoyama M; Masanori Tokumoto; Kazuhiko Tsuruya; Kyoichi Fukuda; Hidetoshi Kanai; Ritsuko Katafuchi; Nagatoshi Y; Hideki Hirakata

A 15-year-old boy developed nephrotic syndrome and acute renal failure 4 years after allogenic bone marrow transplantation (BMT) for lymphoid crisis of chronic myelocytic leukemia. On admission, he presented with clinical features of chronic GVHD including transient exacerbation of cholestatic liver injury. Renal biopsy showed diffuse proliferative glomerulonephritis with cellular crescents. The patient was treated with methylprednisolone pulse therapy (1 g/day, for 3 days) followed by oral prednisolone. Renal function gradually improved but nephrotic state was persistent. A second renal biopsy showed improvement of acute tubular necrosis and endocapillary proliferation and transformation of crescents into a fibrous form. After tapering of oral prednisolone, cyclophosphamide was started, which resulted in a gradual improvement of proteinuria. Several cases of nephrotic syndrome occurring after BMT have already been reported, but most cases had membranous nephropathy. In our case, renal biopsy revealed diffuse proliferative glomerulonephritis with findings of active cellular immunity, and aggressive treatment resulted in attenuation of these findings. Moreover, chronic GVHD-related liver injury was noted at the time of this episode. Our findings suggest that chronic GVHD may be complicated with diffuse proliferative glomerulonephritis through unknown cellular immune mechanism.


Clinical and Experimental Nephrology | 2003

Infusion of radiocontrast agents induces exaggerated release of urinary endothelin in patients with impaired renal function

Kiichiro Fujisaki; Michiaki Kubo; Katsutoshi Masuda; Masanori Tokumoto; Makoto Hirakawa; Hirofumi Ikeda; Rei Matsui; Dai Matsuo; Kyoichi Fukuda; Hidetoshi Kanai; Hideki Hirakata; Mitsuo Iida

BackgroundThe aim of the study was to examine the role of endothelin in radiocontrast-induced nephropathy (RCN) in patients with chronic renal failure.MethodsWe measured plasma endothelin-1 (ET) and the urinary excretion of endothelin-like immunoreactivity before and after infusion of radio contrast medium (CM) in patients with normal renal function (group N; n = 6; mean serum creatinine concentration, 0.8 ± 0.1 (SEM) mg/dl), and in another group, with renal dysfunction (group R; n = 6; 2.7 ± 0.5 mg/dl). Half-normal saline (0.45% NaCl solution) was continuously infused in all patients for 25 h, at a rate of 100 ml/h; starting from 5 h before the infusion of CM.ResultsPlasma ET in group R (5.2 ± 1.4 pg/ml) was significantly higher than in group N (0.9 ± 0.3; P ≪ 0.01). Urinary endothelin excretion corrected by creatinine concentration (uET/Cr) in group R (7.9 ± 2.4 mg/g Cr) was significantly higher than in group N (1.5 ± 0.4 mg/g Cr; P ≪ 0.05). Urinary excretion levels of N-acetyl-Β-d-glucosaminidase (NAG) and Β2-microglobulin (Β2M) were also significantly higher in group R (0.8 ± 0.2 mU/g Cr and 670 ± 400 mg/g Cr, respectively) than in group N (0.3 ± 0.1 and 7.5 ± 2.2, respectively). After CM infusion, uET/Cr in group R significantly increased, to 10.7 ± 2.6 mg/g Cr on the next day and returned to baseline level on the third day. NAG and Β2M showed a similar pattern, but a significant change in NAG was observed on the second day in group R. In group N, uET/Cr, NAG, and Β2M did not change after CM infusion. Plasma ET remained unchanged throughout the observation period of 4 days in both groups. No patient developed pulmonary edema or a significant rise in serum creatinine (more than 0.5 mg/dl), caused by infusion of the amount of half-normal saline used.ConclusionsIn the present study, uET/Cr increased after the administration of CM only in the patients with renal impairment. This difference in endothelin reaction may be a causal one, in that patients with renal insufficiency readily develop RCN. The infusion of half-normal saline starting before CM infusion causes no side effects and is safe for the prevention of CM-induced acute renal failure.


Clinical Nephrology | 2003

Strong polarization toward Th1 immune response in ANCA-associated glomerulonephritis

Masutani K; Masanori Tokumoto; Hiroshi Nakashima; Kazuhiko Tsuruya; Minoru Kashiwagi; Kudoh Y; Kyoichi Fukuda; Hidetoshi Kanai; Mitsuteru Akahoshi; Takeshi Otsuka; Hideki Hirakata; Mitsuo Iida

AIM Human immune response can be classified into 2 different subsets of T helper cells (Th1 and Th2) based on the pattern of cytokine production. In modern immunology, Th1/Th2 paradigm helps to explain the different inflammatory effector pathways and outcomes in human diseases. The present study was designed to determine the type of immunological response that influences anti-neutrophil cytoplasmic antibody-(ANCA) associated glomerulonephritis (GN) using cytokine analysis of peripheral T cells and diseased kidney tissues. PATIENTS AND METHODS We analyzed peripheral blood Th1/Th2 ratio in 91 patients with primary GN, including 10 cases of ANCA-associated GN. Tissues were immunostained with markers of T cells and macrophages and osteopontin (OPN). Intrarenal expression of IFN-gamma and IL-4 mRNAs was evaluated by reverse transcriptase (RT)-PCR. RESULTS Peripheral Th1/Th2 ratio was significantly higher in ANCA-associated GN (19.4 +/- 9.4, mean +/- SD, n = 10), than those in healthy controls (7.6 +/- 4.1, n = 27), IgA nephropathy (9.6 +/- 5.6, n = 45), membranous nephropathy (7.1 +/- 4.4, n = 13), minimal-change nephrotic syndrome (8.2 +/- 4.5, n = 13) and focal segmental glomerulosclerosis (8.3 +/- 3.9, n = 10) (p < 0.01, each). In 7 of 10 cases of ANCA-associated GN, Th1/Th2 ratio decreased significantly after treatment with corticosteroid from 21.0 +/- 12.0 to 9.0 +/- 6.6 (p < 0.05). Immunohistochemical staining showed numerous infiltrating T cells, macrophages and OPN-positive cells in both glomerular tuft and cellular crescent; OPN-positive cell distribution was similar to that of macrophages. Intrarenal expression of IFN-gamma mRNA was strongly enhanced whereas a weak expression of IL-4 mRNA was observed especially in advanced cases showing tubulointerstitial injury. CONCLUSION Both peripheral and renal immune responses are strongly polarized toward Th1 type immune response in ANCA-associated GN. Peripheral Th1/Th2 ratio may reflect the immune responses in renal injury of ANCA-associated GN.


Life Sciences | 1995

The effect of azelastin hydrochloride on pruritus and leukotriene B4 in hemodialysis patients

Hidetoshi Kanai; Akinori Nagashima; Eriko Hirakata; Hideki Hirakata; Seiya Okuda; Satoru Fujimi; Masatoshi Fujishima

Pruritus is a very common complication in chronic hemodialysis (HD) patients, however the exact mechanism for this affliction is still not known. Anti-histaminics usually failed to alleviate uremic pruritus. In others, an anti-allergic drug, which inhibits the release of chemical mediators, such as leukotrienes or histamine from mast cells, was reported to be effective. We evaluated the values of leukotriene B4 and interleukin 6 in HD patients with pruritus and the effect of an anti-allergic drug on these factors. Leukotriene B4, interleukin-6, C3a, C5a, the number of eosinophil and IgE at 0, 15 and 180 minutes after the start of regular HD in 11 HD patients suffering from pruritus and as well as in 11 HD patients without pruritus were examined. These HD patients in both groups showed significantly higher (p < 0.001) values of leukotriene B4 and C3a compared to healthy non-HD subjects. There was no difference in the leukotriene B4, interleukin-6, IgE, C3a and C5a levels between the patients with and without pruritus. Two mg/day of azelastin hydrochloride, an anti-allergic drug was orally given to the pruritus group for 3 weeks. In 5 of 11 patients, the pruritus symptoms disappeared, while in 4 of 11 they improved. Independent of the effect of the drug on pruritus, leukotriene B4 levels significantly decreased compared with those before the administration of this drug in the pruritus group (p < 0.01). Interleukin 6, C3a, C5a and the number of eosinophils demonstrated no significant change. In conclusion, although azelastin hydrochloride was effective in treating pruritus and also suppressed leukotriene B4 levels in hemodialysis patients, the high leukotriene B4 activity itself did not seem to be related to the development of pruritus in these patients.


Clinical Transplantation | 2005

Recurrent nephrotic syndrome after living-related renal transplantation resistant to plasma exchange: report of two cases

Kohsuke Masutani; Ritsuko Katafuchi; Hirofumi Ikeda; Hirofumi Yamamoto; Kentaro Motoyama; Atsushi Sugitani; Hidetoshi Kanai; Harumitsu Kumagai; Hideki Hirakata; Masao Tanaka; Mitsuo Iida

Abstract:  We encountered two patients of recurrent nephrotic syndrome (NS) after renal transplantation that was resistant to plasma exchange (PEX). Case 1 was a 34‐year‐old man with a living‐related renal transplant for type‐I membranoproliferative glomerulonephritis (MPGN) related end‐stage renal disease (ESRD). He developed overt proteinuria 7 months post‐transplant and presented with NS 5 months later. Biopsy of the transplant kidney revealed recurrent type I MPGN, but no features of acute rejection (AR) or chronic allograft nephropathy (CAN). He was treated with cyclophosphamide (CP), oral prednisolone (40 mg/d), an anti‐platelet agent, heparin sulfate, and PEX, but the nephrotic state persisted and renal function was deteriorated. He recommenced hemodialysis 3 yr and 9 months after renal transplant. Case 2 was a 47‐year‐old male who underwent living‐related renal transplant for ESRD due to focal segmental glomerulosclerosis (FSGS). He presented with proteinuria shortly after renal transplantation. He also had frequent episodes of AR. Graft biopsy revealed recurrent FSGS. Treatment of pulse methylprednisolone and PEX was transiently effective, but NS relapsed shortly after PEX. Graft biopsy at our hospital showed features of CAN with moderate interstitial fibrosis and tubular atrophy, presence of intraglomerular foam cells but no segmental sclerosis. Treatment with 12 courses of low‐density lipoprotein apheresis (LDL‐A) reduced proteinuria from 9.6 to 2.0 g/d, and incomplete remission has been maintained for more than 1 yr after LDL‐A with slowly progressive renal dysfunction. Despite recent therapeutic advances, including the use of immunosuppressants and PEX, treatment of recurrent disease remains difficult. The LDL‐A might be useful in cases with recurrent FSGS resistant to PEX.


Therapeutic Apheresis and Dialysis | 2007

Midodrine hydrochloride and L-threo-3,4-dihydroxy-phenylserine preserve cerebral blood flow in hemodialysis patients with orthostatic hypotension

Kiichiro Fujisaki; Hidetoshi Kanai; Hideki Hirakata; Sachiko Nakamura; Yuko Koga; Fumitada Hattori; Mitsuo Iida

Abstract:  Orthostatic hypotension (OH) after hemodialysis (HD) is a serious complication, as it causes various neurological symptoms and even ischemic brain damage. The aim of the present study was to evaluate the effects of antihypotensive agents, midodrine hydrochloride (MID) and l‐threo‐3,4‐dihydroxyphenylserine (L‐DOPS), on OH after HD. We measured systolic blood pressure (SBP) and cerebral blood flow velocity in the middle cerebral artery (MCVm, by transcranial Doppler sonography), in patients with OH during a 5‐min 60‐degree head‐up tilt test at both before and after 4‐week treatment with MID at 4 mg/day (N = 6) or L‐DOPS at 400 mg/day (N = 7). Both MID and L‐DOPS did not significantly protect against falls in systolic BP (SBP) after passive head‐up tilt. However, a significant improvement was achieved in MCVm‐decrement in the MID group at 3 min and the L‐DOPS group at 0, 1 and 3 min during head‐up tilt. Although MID and L‐DOPS did not prevent OH after HD in HD patients, both agents preserved cerebral blood flow during orthostasis in HD patients with OH. 


Nephron | 1992

Synthesis of Fibronectin by Isolated Glomeruli from Nephrectomized Hypertensive Rats

Seiya Okuda; Hidetoshi Kanai; Kiyoshi Tamaki; Kaoru Onoyama; Masatoshi Fujishima

The accumulation of extracellular matrix (ECM) is an important feature of most forms of progressive glomerular diseases. In order to examine the relationship between ECM synthesis and glomerulosclerosis, we evaluated fibronectin synthesis by glomeruli with the immunoprecipitation of conditioned media from isolated glomeruli in 5/6 nephrectomized spontaneously hypertensive rats (5/6N-SHR). There was no difference in blood pressure between 5/6N-SHR and control SHR throughout the experiment. Two weeks after the nephrectomy, most of the glomeruli were intact and no difference in the synthesis of fibronectin was observed between either groups. Twenty weeks after the nephrectomy, marked glomerulosclerosis associated with an increase in urinary protein was revealed in 5/6N-SHR but no glomerular lesions in control SHR. The synthesis of fibronectin by isolated glomeruli increased in 5/6N-SHR compared to control SHR. The administration of enalapril or hydralazine + reserpine + hydrochlorothiazide markedly attenuated the glomerular sclerosis and urinary protein excretion to a comparable degree, although the later therapy reduced blood pressure more effectively. These antihypertensive therapies also suppressed fibronectin synthesis in the 5/6N-SHR group at week 20. In conclusion, increased synthesis of glomerular fibronectin appeared to contribute to the glomerulosclerosis caused by subtotal nephrectomy and hypertension.

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