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Dive into the research topics where Yuichi Takama is active.

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Featured researches published by Yuichi Takama.


Xenotransplantation | 2010

Complement regulation in the GalT KO era

Shuji Miyagawa; Aki Yamamoto; Katsuyoshi Matsunami; Dandan Wang; Yuichi Takama; Takehisa Ueno; Masaru Okabe; Hiroshi Nagashima; Masahiro Fukuzawa

Miyagawa S, Yamamoto A, Matsunami K, Wang D, Takama Y, Ueno T, Okabe M, Nagashima H, Fukuzawa M. Complement regulation in the GalT KO era.
Xenotransplantation 2010; 17: 11–25.


Journal of Pediatric Surgery | 2010

Diagnosis and management of biliary cystic malformations in neonates

Natsumi Tanaka; Takehisa Ueno; Yuichi Takama; Masahiro Fukuzawa

PURPOSE Recent advances in ultrasonography have made it possible to identify biliary atresia (BA) and choledochal cyst (CC) with biliary cystic malformations (BCM) both prenatally and neonatally. The early differential diagnosis between BA and CC is extremely important because operations must be performed as soon as possible before the livers of BA patients advance to an irreversible cirrhotic stage. The aim of this study was to differentiate patients with BCM and to determine the best course of management in the neonatal period. METHODS The medical records of patients that were diagnosed with BCM by a prenatal or neonatal ultrasound between 1997 and 2008 were reviewed. We retrospectively divided the BCM patients into the BA and CC groups and then compared the results of ultrasound, computed tomography, and laboratory tests between the 2 groups. RESULTS Ten patients were enrolled in the study. The median age at the time of corrective surgery was 74 days (range, 24-206 days). All of the BA cases received an operation by the time they were 60 days old. In the BA group (5 patients), the mean cyst size was 15 mm, the mean direct bilirubin (D-Bil) was 3.3 mg/dL, and the mean total bile acid (TBA) was 138.1 µmol/L at 30 days of age, whereas in the CC group (5 patients), cyst size, D-Bil, and TBA were 40 mm, 0.9 mg/dL, and 46.9 µmol/L, respectively. These differences between the 2 groups were statistically significant. All of the patients with CC successfully cleared their jaundice, whereas 4 patients with BA subsequently required liver transplantation for liver failure. In our study, all patients with BCM less than 21 mm, D-Bil greater than 2.5 mg/dL, and TBA greater than 111 µmol/L in the neonatal period were diagnosed with BA. CONCLUSIONS Our data suggested that patients with BCM smaller than 21 mm, D-Bil higher than 2.5 mg/dL, and TBA higher than 111 µmol/L in the neonatal period were more likely to have BA than CC. This potential diagnosis should be surgically examined and corrected as soon as possible.


Pediatric Transplantation | 2011

Graft fibrosis in patients with biliary atresia after pediatric living‐related liver transplantation

Takehisa Ueno; Natsumi Tanaka; Yoshiyuki Ihara; Yuichi Takama; Hiroyuki Yamada; Sotaro Mushiake; Masahiro Fukuzawa

Ueno T, Tanaka N, Ihara Y, Takama Y, Yamada H, Mushiake S, Fukuzawa M. Graft fibrosis in patients with biliary atresia after pediatric living‐related liver transplantation. 
Pediatr Transplantation 2011: 15: 470–475.


The Annals of Thoracic Surgery | 2010

Three-Stage Reconstruction of the Airway and Alimentary Tract in a Case of Tracheal Agenesis

Noriaki Usui; Masafumi Kamiyama; Gakuto Tani; Yuichi Takama; Hideki Soh; Shuichiro Uehara; Masahiro Fukuzawa

In the few surviving cases of tracheal agenesis, infants have not been capable of oral intake because the esophagus was used as a substitute for the trachea. We performed a three-stage reconstruction of the airway and alimentary tract in an infant with tracheal agenesis. This procedure involved a double cervical esophagostomy followed by an anastomosis of the upper mid-esophagus and carinal trachea. Finally, the esophagus was reconstructed by an anastomosis of the cervical esophagus to the lower esophagus. This novel procedure may become a highly effective surgical treatment for some infants in critical condition due to tracheal agenesis.


Journal of Pediatric Surgery | 2011

Expression of Wilms tumor 1 gene in a variety of pediatric tumors

Takaharu Oue; Shuichiro Uehara; Hiroaki Yamanaka; Yuichi Takama; Yusuke Oji; Masahiro Fukuzawa

BACKGROUND/PURPOSE Wilms tumor 1 (WT1) gene is overexpressed in many types of neoplasms, thus suggesting that WT1 has oncogenic properties. Therefore, WT1 is a molecular target for cancer therapy. The objectives of this study were to evaluate the WT1 gene expression in various pediatric tumors and to elucidate that WT1 can be a target of cancer therapy in pediatric malignancies. PATIENTS AND METHODS The expression of WT1 protein was examined in 60 cases of primary pediatric tumors. The levels of WT1 messenger RNA (mRNA) expression were examined by a quantitative real-time reverse transcriptase polymerase chain reaction analysis in frozen tissue samples from 56 cases with pediatric tumors. RESULTS Immunohistochemical staining revealed that WT1 protein was widely detected in pediatric malignancies. The alveolar subtype of rhabdomyosarcoma showed more intensive staining than the embryonal subtype. The positive rate of the alveolar type was significantly higher than that of the embryonal type. The expression of WT1 mRNA in the tumor samples varied widely. However, no significant correlation was observed between WT1 mRNA expression and clinical factors. CONCLUSION The WT1 expression was broadly detected in various pediatric neoplasms. These results indicate that WT1 may therefore be a potentially useful therapeutic target in most of pediatric malignancies.


Journal of Pediatric Surgery | 2013

Familial Currarino syndrome associated with Hirschsprung disease: two cases of a mother and daughter.

Koichi Ohno; Tetsuro Nakamura; Takashi Azuma; Tatsuo Nakaoka; Yuichi Takama; Hiroaki Hayashi; Masaki Horiike; Masahiro Zenitani; Atsushi Higashio

Currarino syndrome with Hirschsprung disease (CS-HD) is extremely rare. We present the first family with CS-HD. Case 1: A 28-year-old woman was admitted with severe abdominal distension and dyspnea. She was diagnosed with anal stenosis, hemisacrum, anterior sacral meningocele (ASM), tethered cord (TC), and short-segment aganglionosis. She underwent the modified Duhamel operation after meningocele repair and cord detethering. A bicornuate uterus, bilateral ovarian dermoid cysts, and small rectal duplication were also noted intraoperatively. Case 2: The daughter of case 1 was admitted for abdominal distension and anal stenosis at the age of 17 days. Studies revealed a hemisacrum, ASM, TC, presacral mass, atrial septal defect, polyp in the right nasal cavity, right vesicoureteral reflux, and short-segment aganglionosis. She underwent the modified Soave operation at the age of 1 year and 4 months after meningocele repair, cord detethering, and resection of the presacral mass (epidermoid cyst). In both cases, the aganglionic segments were confirmed by preoperative rectal suction biopsy and postoperative pathological examination on full-thickness rectal specimens. Some causal genes for Currarino syndrome (CS) and Hirschsprung disease (HD) are currently investigated. Thus far, 10 CS-HD cases have been reported, including 6 cases of familial CS. However, all the patients had sporadic HD. Recent reports suggest that anomalies of the enteric nerve system contribute to postoperative constipation in CS cases.


Surgery Today | 2013

Trial using pig cells with the H–D antigen knocked down

Aki Yamamoto; Kosuke Ikeda; Dandan Wang; Shino Nakatsu; Yuichi Takama; Takehisa Ueno; Hiroshi Nagashima; Akihiro Kondo; Masahiro Fukuzawa; Shuji Miyagawa

PurposeThis report describes an attempt to reduce the expression level of Hanganutziu–Deicher (H–D) antigens by small interfering RNA (siRNA) for pig cytidine monophospho-N-acetylneuraminic acid hydroxylase (pCMAH).MethodsA pig endothelial cell (PEC) line, and PEC and fibroblasts from an α1,3galactosyltransferase knockout (GalT-KO) piglet were used. Real-time PCR was used to evaluate the degradation of mRNA by siRNA. The H–D antigen was stained, and then the cells were incubated with human serum for the FACS analysis. The extent of lysis in human serum was next calculated using an LDH assay.ResultsSuppression of the mRNA of pCMAH by each siRNA was first determined. The mixture of siRNAs for pCMAH reduced the expressions of the H–D antigen on the PEC and fibroblasts to a considerable extent. The further reduction in the xenoantigenicity for human serum of the GalT-KO cells was then confirmed. In addition, the PEC line showed a significant downregulation in complement-dependent cytotoxicity by the siRNAs, thus indicating that the anti-H–D antigen in human serum is capable of causing lysis of the pig cells.ConclusionpCMAH silencing by siRNA reduced the expression of the H–D antigen and its antigenicity, thus confirming that the H–D antigen is one of the major non-Gal antigens in this situation.


Transplant Immunology | 2011

Effects of a calcineurin inhibitor, FK506, and a CCR5/CXCR3 antagonist, TAK-779, in a rat small intestinal transplantation model

Yuichi Takama; Shuji Miyagawa; Aki Yamamoto; S. Firdawes; Takehisa Ueno; Yoshiyuki Ihara; Akihiro Kondo; Katsuyoshi Matsunami; Hideaki Otsuka; Masahiro Fukuzawa

The effects of FK506, and TAK-779, antagonists of CCR5 and CXCR3, were investigated using a rat intestinal transplantation model. Small intestines from DA rats were heterotopically transplanted into LEW rats. The recipients were treated with FK506 (1mg/kg/day, day 0-5) and TAK-779 (10mg/kg/day, day 0-10). Graft survival and immunological responses to these materials were estimated by mixed lymphocyte reactions and IFN-γ production. The expression of chemokine receptors on lymphocytes was also examined. The average duration of survival was 7.0±0.3, 12.0±1.0, 9.8±0.5 and 18.0±1.5days in the allogeneic, FK506, TAK-779 and the two-drug combined groups, respectively. Cell proliferative responses and IFN-γ production were suppressed to a significant extent in the FK506 group compared with the TAK-779 group. In addition, the two-drug combination showed a tendency for stronger suppression than FK506 alone, correlated with in vivo and histopathological data. The numbers of both CD4(+) and CD8(+) cells were significantly suppressed in the blood of the recipients of both the FK506 and the TAK-779 groups, and in Peyers patches of the graft of the TAK-779 group, but the FK506 group was not, as evidenced by FACS analysis. In addition, double-staining of graft-infiltrating lymphocytes showed a significant reduction in lymphocyte numbers, expressing CCR5 and CXCR3 in the TAK-779 group, but not evident in the FK506 group, compared to the allogeneic group. While FK506 suppresses cell proliferation and effecter function, it has less effect on the expression of CCR5 and CXCR3 in lymphocytes. Further exploration of the effects of a combined therapy with TAK-779 could represent a novel treatment for intestinal transplantation.


European Journal of Pediatric Surgery | 2015

Early Detection and Treatment of Neuroblastic Tumor with Opsoclonus-Myoclonus Syndrome Improve Neurological Outcome: A Review of Five Cases at a Single Institution in Japan

Yuichi Takama; Akihiro Yoneda; Tetsuro Nakamura; Tatsuo Nakaoka; Atsushi Higashio; Kenji Santo; Ichiro Kuki; Hisashi Kawawaki; Kiyotaka Tomiwa; Junichi Hara

INTRODUCTION Opsoclonus-myoclonus syndrome (OMS) is a paraneoplastic neurological disorder associated with neuroblastic tumor (NT) in childhood. Half of patients have neurological sequelae after the neurological and oncological treatment. We reviewed the neurological and oncological outcomes of NT with OMS, and discussed whether the treatment of NT would contribute to improving the neurological prognosis. METHODS We retrospectively assessed NT patients with OMS from January 2001 to December 2013 at a single institution in Japan. Demographic data, neurological and oncological status, histopathology, treatments, prognosis, and diagnosis and treatment timing were retrospectively reviewed from the records. The timings assessed were the interval between OMS onset and NT detection, initial NT therapy, and initial OMS therapy, the interval between NT therapy and OMS remission, and duration of OMS. RESULTS A total of 73 patients with NT were treated during the study period, and 5 of 73 patients were diagnosed as having NT with OMS. The median age at onset of OMS was 22 months (range, 18-30 months). The median age at detection of NT was 29 months (range, 21-33 months). Three of five cases showed no uptake on meta-iodobenzylguanidine scintigraphy. The tumor histopathology was neuroblastoma in two patients, ganglioneuroblastoma in two patients, and ganglioneuroma in one patient. Primary resection was performed in three cases. All patients survived. Two of five cases presented with atypical neurological symptoms without opsoclonus. The initial neurological therapy was started within a mean of 20 days (range, 3-76 days) from the onset of OMS in all cases. Four patients received intravenous immunoglobulin, and one with persistent neurological problems received rituximab. Neurological symptoms resolved in three cases. The mean interval between the onset of OMS and the detection of NT in case without neurological sequelae was 57 days (range, 25-113 days), while in case with neurological sequelae it was 365 days (range, 271-458 days). The mean interval between onset of OMS and initial therapy for NT in case without neurological sequelae was 88 days (range, 47-145 days), while in case with neurological sequelae it was 389 days (range, 292-486 days). CONCLUSION The interval between the onset of OMS and the detection and initial therapy of NT tended to be longer in patients with neurological sequelae than in those without neurological sequelae. This study suggested that early detection and treatment of NT with OMS might improve the neurological outcomes.


Clinical Genetics | 2015

Autosomal recessive cystinuria caused by genome-wide paternal uniparental isodisomy in a patient with Beckwith-Wiedemann syndrome.

Yasufumi Ohtsuka; Ken Higashimoto; Kensaku Sasaki; Kosuke Jozaki; H. Yoshinaga; Nobuhiko Okamoto; Yuichi Takama; Akio Kubota; Masahiro Nakayama; Hitomi Yatsuki; Kenichi Nishioka; Keiichiro Joh; Tsunehiro Mukai; Koh-ichiro Yoshiura; Hidenobu Soejima

Approximately 20% of Beckwith–Wiedemann syndrome (BWS) cases are caused by mosaic paternal uniparental disomy of chromosome 11 (pUPD11). Although pUPD11 is usually limited to the short arm of chromosome 11, a small minority of BWS cases show genome‐wide mosaic pUPD (GWpUPD). These patients show variable clinical features depending on mosaic ratio, imprinting status of other chromosomes, and paternally inherited recessive mutations. To date, there have been no reports of a mosaic GWpUPD patient with an autosomal recessive disease caused by a paternally inherited recessive mutation. Here, we describe a patient concurrently showing the clinical features of BWS and autosomal recessive cystinuria. Genetic analyses revealed that the patient has mosaic GWpUPD and an inherited paternal homozygous mutation in SLC7A9. This is the first report indicating that a paternally inherited recessive mutation can cause an autosomal recessive disease in cases of GWpUPD mosaicism. Investigation into recessive mutations and the dysregulation of imprinting domains is critical in understanding precise clinical conditions of patients with mosaic GWpUPD.

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