Ryuto Nakazawa
St. Marianna University School of Medicine
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Transplantation Proceedings | 2008
Tatsuya Chikaraishi; Hideo Sasaki; Hisashi Tsutsumi; Satetsu Miyano; Ryuto Nakazawa; T. Nakano; Kazuki Kitajima; H. Kudo; T. Takahashi; Yuichi Sato; Kenjiro Kimura
We have designed a protocol for ABO-incompatible kidney transplantations based on preoperative plasmapheresis with a tacrolimus/mycophenolate mofetil/methylprednisolone/basiliximab protocol using low-dose rituximab (200 mg/body) instead of splenectomy to prevent antibody-mediated acute rejection. Eight patients successfully received transplants with this protocol. The titers of anti-A and -B antibodies as well as the number of CD20(+) cells were readily maintained at a low level posttransplantation. There were no side effects. All patients have renal transplant function with a follow-up of 1-34 months.
Transplantation proceedings | 2016
H. Maekawa; Masahiko Yazawa; K. Koitabashi; Naohiko Imai; Hiroo Kawarazaki; Ryuto Nakazawa; Hideo Sasaki; Tatsuya Chikaraishi; Yugo Shibagaki
BACKGROUND Hepatitis B virus (HBV) infection is a risk factor of mortality in kidney transplant recipients. However, information on the risk of HBV reactivation in kidney recipients with prior resolved HBV infection is limited. This study aimed to evaluate the safety of simply monitoring viral and liver markers in living donor kidney transplantation (LDKT) recipients with prior resolved HBV infection. METHODS We retrospectively examined the clinical records of LDKT recipients. Changes in the levels of alanine aminotransferase, aspartate aminotransferase, hepatitis B surface antigen (HBs Ag), surface antibody, core antibody, and HBV-DNA after transplantation were evaluated, and the occurrence of de novo HBV-related hepatitis and allograft function were monitored. RESULTS Of 61 consecutive LDKT patients, seven had prior resolved HBV infection. Four patients underwent ABO-compatible LDKT, whereas two underwent ABO-incompatible LDKT. The median age was 64 years (range, 61-69 years), and two patients were women. The causes of end-stage kidney disease were diabetic nephropathy, hypertensive nephrosclerosis, and chronic glomerulonephritis. Five patients were referred to hepatologists. The history of HBV vaccination was not confirmed in all patients. Prophylaxis with entecavir was administered to two patients with ABO-incompatible LDKT before transplantation. All patients tested negative for HBs Ag and HBV-DNA throughout observation, and none developed de novo HBV-related hepatitis or graft loss. CONCLUSIONS Patients with HBV infection without HBV DNA positivity are eligible for kidney transplants without antiviral therapy, even those on rituximab therapy. Monitoring viral and liver markers combined with hepatologist consultations may ensure safe follow-up in LDKT recipients with prior resolved HBV infection.
International Journal of Urology | 2011
Ryuto Nakazawa; Satetsu Miyano; Hideo Sasaki; Hiroya Kudo; Kenjiro Kimura; Tatsuya Chikaraishi
Synchronous bilateral urothelial cancer is very rare. We report a 25‐year‐old male kidney recipient with Alport syndrome who developed bilateral synchronous urothelial cancer after transplantation. At the age of 16 this patient was referred to our clinic for a kidney transplantation. A living related donor kidney transplantation was performed with cyclosporin‐based quadruple immunosuppression. He experienced no acute rejection and his graft function was excellent after transplantation. Nine years after transplantation, he complained of asymptomatic gross hematuria and was diagnosed as having a bilateral urothelial cancer in the native upper urinary tracts. A bilateral total nephroureterectomy was undertaken, and the postoperative pathological diagnosis was advanced bilateral urothelial carcinoma. The patient received adjuvant gemcitabine plus cisplatin chemotherapy at a cisplatin dosage reduced by 50%. After 4 years of follow‐up, he is alive with a functioning graft and no evidence of recurrence.
International Journal of Urology | 2009
Ryuto Nakazawa; Shun Soneda; Akitoshi Kinoshita; Hiroaki Kitagawa; Junki Koike; Tatsuya Chikaraishi
Abstract: A 2‐year‐old boy, who had the chief complaints of penile swelling and pain, was brought to the hospital by his mother. Penile contusion/trauma was suspected and he was admitted the same day to undergo emergency surgery to eliminate hematoma. The surgery revealed that the origin of the bleeding was not trauma but a tumor lesion of the penile shaft. It was histopathologically identified as a yolk sac tumor and no tumorous lesions were found except that in the penis. Therefore the patient was diagnosed as definitely having a yolk sac tumor originating in the penis. The patient received four cycles of cisplatin, etoposide and bleomycin treatment as adjuvant chemotherapy. Although it was impossible to completely resect the tumor, cisplatin, etoposide and bleomycin chemotherapy was effective and a complete response was achieved. We plan to carefully monitor the patient in the future.
Transplantation Proceedings | 2015
Hideo Sasaki; Yuichi Sato; E. Matsuhashi; T. Nishi; S. Hachisuka; Yuichi Katsuoka; Hiroya Kudo; Kazuki Kitajima; M. Yoshioka; Ryuto Nakazawa; Satetsu Miyano; Masahiko Yazawa; Naohiko Imai; Hiroo Kawarazaki; Yugo Shibagaki; Kenjiro Kimura; Tatsuya Chikaraishi
BACKGROUND In kidney transplant recipients, the most widely used method for the reconstruction of the urinary pathway is ureteroneocystostomy, which may be difficult in cases with disused atrophic bladder. In this study, we evaluated kidney transplant recipients who underwent uretero-ureteral end-to-side anastomosis (UUA) in urinary reconstruction due to disused atrophic bladder. METHODS To clarify the effectiveness of this method, we retrospectively reviewed the clinical records of kidney transplant recipients in our hospital. RESULTS A total of 9 recipients with urinary reconstruction using UUA were evaluated. All of these patients had a history of long-term hemodialysis before transplantation, accompanied by complete anuria and small capacity of the bladder. In 4 patients, cranial native ureter was ligated, whereas it was not ligated in the remaining 5 patients. In 2 of 4 patients with cranial ligation, hydronephrosis developed in the native kidney with no further treatment being required. No patients experienced urinary tract complications including hydronephrosis in the graft, urine extravasation, or urinary tract infection in the follow-up period (757.6 ± 491.3 days). Allograft function was maintained well in all patients (serum creatinine level, 1.08 ± 0.23 mg/dL). CONCLUSIONS Although UUA is not a routine method of urinary reconstruction in kidney transplantation, it can be safely performed and should be a surgical option, especially for recipients with disused atrophic bladder. The ligation of cranial native ureter may lead to hydronephrosis of the native kidney, and it is tentatively concluded that UUA without native ureteral ligation is clinically feasible.
Transplantation Proceedings | 2000
Hideo Sasaki; Tatsuya Chikaraishi; S. Furuhata; Hisashi Tsutsumi; Satetsu Miyano; Ryuto Nakazawa; T. Nakano; H. Kudo; Kazuki Kitajima; T. Takahashi; Y. Satoh; Kenjiro Kimura
Autologous blood transfusion (ABT) is rarely employed in patients with end-stage renal disease (ESRD); these patients are usually anemic. Since 1998, we have attempted ABT for ESRD patients undergoing living-related kidney transplantation. Among 20 patients enrolled in this study the preoperative hemoglobin and hematocrit levels were 10.0 +/- 1.2 mg/dL (range, 8.1-11.7) and 30.0 +/- 3.7% (range, 24.7-34.3), respectively. Blood volume collected on each occasion was 235.7 +/- 57.7 mL (range, 200-400), and the number of blood collections was 2.45 +/- 0.9 (range, 1-4). Total collected volume was 567.5 +/- 157.5 mL (range, 400-800). Symptomatic hypotension was seen in two patients, but vital signs recovered spontaneously. No other problems related to blood collection were observed. Allogeneic transfusion was need in only one patient (5%). ABT was safe and efficacious in ESRD patients scheduled for living-related kidney transplantation.
Case reports in urology | 2016
Wataru Usuba; Hideo Sasaki; Hidekazu Yoshie; Kazuki Kitajima; Hiroya Kudo; Ryuto Nakazawa; Yuichi Sato; Masayuki Takagi; Tatsuya Chikaraishi
Solitary fibrous tumor (SFT) of the kidney is a rare entity and usually displays a favorable prognosis. We herein report a second case of renal SFT developing local recurrence. A 50-year-old man was referred to our hospital because of a left renal mass. An abdominal CT detected a large renal tumor and radical nephrectomy was performed with a possible diagnosis of renal cell carcinoma. The resected tumor size was measured at 17 × 11 × 8 cm. Grossly, necrosis was observed in central lesion of the tumor but hemorrhage was not observed. Microscopically, the tumor consisted of spindle-shaped cells with scant cytoplasm accompanied by hyalinized collagenous tissue, which displayed hemangiopericytomatous patterns. The cellularity was normal and nuclear pleomorphism was not observed. Ki-67 labeling index was less than 3%. The pathological diagnosis of SFT was made without obvious malignant findings. Three years after the surgery, a follow-up CT scan detected a mass lesion in the tumor bed. Surgical resection was performed and the resected tumor was compatible with local recurrence of the SFT without obvious malignant findings. Renal SFT should be carefully monitored even in the absence of obvious malignant findings.
International Journal of Urology | 2015
Ryuto Nakazawa; Yuichi Sato; Hideo Sasaki; Yugo Shibagaki; Kenjiro Kimura; Tatsuya Chikaraishi
Here we report therapeutic drug monitoring of cyclosporine in a kidney transplant recipient lacking enterohepatic circulation. The patient developed steroid‐resistant nephrotic syndrome at age 14 years, and was medicated with an oral cyclosporine microemulsion. However, her cyclosporine trough level was unexpectedly elevated, and subsequent investigations showed that she was deficient in drug metabolism as a result of the congenital absence of the portal vein. Her renal function gradually decreased and she became dialysis‐dependent at the age of 21 years, and kidney transplantation was planned. Based on pretransplant therapeutic drug monitoring, we started cyclosporine microemulsion at half of the conventional dosage. After transplantation, the dosage was successfully adjusted to achieve a target trough level. The post‐transplant course was stable with no symptoms of rejection or cyclosporine‐associated nephrotoxicity.
Nephrology | 2014
Kazuki Kitajima; Hideo Sasaki; Junki Koike; Ryuto Nakazawa; Yuichi Sato; Masahiko Yazawa; Kayo Tsuruoka; Hiroo Kawarazaki; Naohiko Imai; Sayuri Shirai; Yugo Shibagaki; Tatsuya Chikaraishi
Post‐transplant lymphoproliferative disorder (PTLD) is a neoplastic complication with a potentially fatal outcome that develops as a consequence of immunosuppression, and is mainly associated with Epstein‐Barr virus (EBV) infection. A 70‐year‐old woman underwent a live unrelated, ABO‐incompatible renal transplant for end‐stage renal disease. One year after transplantation, protocol biopsy revealed pathological changes indicative of the histological subtype of ‘early lesions of PTLD’ according to the World Health Organization classification, while the patient showed no clinical signs or symptoms. The patient was finally diagnosed with EBV‐positive PTLD by in situ hybridization for EBER (EBV‐encoded RNA), and was successfully treated based on the reduction of immunosuppression. Protocol biopsy within the first post‐transplant year is the only diagnostic measure to detect asymptomatic early PTLD, which allows for early intervention and leads to better outcomes.
Journal of Artificial Organs | 2010
Yuichi Sato; Masahito Miyamoto; Masahiko Yazawa; Ryuto Nakazawa; Hideo Sasaki; Satetsu Miyano; Hisashi Tsutsumi; Kenjiro Kimura; Tatsuya Chikaraishi
As the number of patients on hemodialysis increases, there will also be an increase in the number of patients with inadequate superficial veins for the creation of an autogenous arteriovenous fistula (AVF). In those patients, medical devices such as vascular prostheses or tunneled-cuffed catheters are necessary to maintain dialysis access. However, these devices are frequently associated with bacterial infection. We recently encountered a dialysis patient who underwent tunneled-cuffed catheter insertion because of the lack of usable superficial veins for autogenous access, and this patient subsequently developed catheter-related Staphylococcus aureus bacteremia with multiple metastatic infections. Despite immediate removal of the catheter, the infection persisted over an extended period, which was a condition precluding the further use of catheters or other prosthetic materials. To handle this situation, we utilized the deep brachial vein to construct an autogenous AVF. After ligating numerous branches, the vein was anastomosed to the brachial artery and then transposed to the subcutaneous space. The newly constructed autogenous AVF, which successfully kept the patient free from foreign materials, greatly contributed to the relief of persistent infection. Although the brachial vein is rarely used for AVF creation, we suggest that it can serve as an option to create an alternative AVF in a patient with inadequate superficial veins.