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Featured researches published by Tatsushi Naito.


Cancer Letters | 2015

High-dose cyclophosphamide induces specific tumor immunity with concomitant recruitment of LAMP1/CD107a-expressing CD4-positive T cells into tumor sites

Tatsushi Naito; Tomohisa Baba; Kazuyoshi Takeda; Soichiro Sasaki; Yasunari Nakamoto; Naofumi Mukaida

Cancer chemotherapy regimens, particularly those employing high-dose cytotoxic drugs such as cyclophosphamide (CTX), have been considered to be immune suppressive. However, we observed that a single administration of high-dose CTX abolished tumors arising from subcutaneous injection of a mouse hepatoma cell line and subsequently induced specific tumor immunity. Depletion of T cells, specifically CD4(+) T cells, abrogated the CTX-mediated tumor regression. CTX treatment induced the rapid recruitment of CD4(+) T cells into the tumors, and these recruited cells initiated expression of LAMP1/CD107a, a cytotoxic granule molecule, and granzyme B in the absence of antigen presentation at draining lymph nodes and proliferation in the tumor tissues. Moreover, CTX enhanced the expression of a CC chemokine, CCL3, in tumor tissues, and CTX-mediated tumor regression was attenuated in mice deficient in CCR5, the receptor for this chemokine. Consistently, less CTX-induced accumulation of intratumoral LAMP1/CD107a-expressing CD4(+) T cells was observed in mice receiving splenocytes derived from CCR5-deficient mice than in those receiving splenocytes derived from WT mice. Thus, CTX induces the expression of CCL3, which induces the intratumoral migration of CD4(+) T cells expressing cytotoxic molecules, leading to tumor eradication and subsequent specific tumor immunity.


BMC Clinical Pathology | 2015

Ruptured hepatic metastases of cutaneous melanoma during treatment with vemurafenib: an autopsy case report

Takuto Nosaka; Katsushi Hiramatsu; Tomoyuki Nemoto; Yasushi Saito; Yoshihiko Ozaki; Kazuto Takahashi; Tatsushi Naito; Kazuya Ofuji; Hidetaka Matsuda; Masahiro Ohtani; Hiroyuki Suto; Yoshiaki Imamura; Yasunari Nakamoto

BackgroundThe spontaneous rupture of hepatic metastases is rare compared to that of primary hepatic tumors. In addition, vemurafenib, a selective inhibitor of the mutant BRAF protein or gene product, has been reported to be extremely effective in patients with metastatic melanoma who harbor a BRAF V600E mutation.Case presentationA 44-year-old female had previously undergone surgery for resection of a malignant melanoma in the lower right leg. Four years later, hepatic metastases became apparent, and transcatheter arterial embolization (TAE) was performed. Then she underwent treatment with vemurafenib. The size of the hepatic metastases markedly decreased. Two months later, they enlarged rapidly and ruptured, requiring emergency TAE. However, the patient developed hemorrhagic shock and died of renewed intra-abdominal bleeding on the 26th postoperative day.ConclusionsThis is a rare case of ruptured hepatic metastases of malignant melanoma during treatment with vemurafenib. Postmortem examination and immunohistochemical analysis indicated reactivation of the mitogen-activated protein kinase pathway in the metastatic tumor, suggesting secondary resistance to vemurafenib as the possible underlying mechanism.


PLOS ONE | 2017

Gene expression profiling of hepatocarcinogenesis in a mouse model of chronic hepatitis B

Takuto Nosaka; Tatsushi Naito; Katsushi Hiramatsu; Masahiro Ohtani; Tomoyuki Nemoto; Hiroyuki Marusawa; Ning Ma; Yusuke Hiraku; Shosuke Kawanishi; Taro Yamashita; Shuichi Kaneko; Yasunari Nakamoto

Background Hepatocellular carcinoma (HCC) is a common complication of chronic viral hepatitis. In support of this notion, we have reported that hepatitis B surface antigen (HBsAg)-specific CD8+ T lymphocytes critically contribute to inducing chronic liver cell injury that exerts high carcinogenic potential in a hepatitis B virus (HBV) transgenic mouse model. The dynamics of the molecular signatures responsible for hepatocellular carcinogenesis are not fully understood. The current study was designed to determine the serial changes in gene expression profiles in a model of chronic immune-mediated hepatitis. Methods Three-month-old HBV transgenic mice were immunologically reconstituted with bone marrow cells and splenocytes from syngeneic nontransgenic donors. Liver tissues were obtained every three months until 18 months at which time all mice developed multiple liver tumors. Nitrative DNA lesions and hepatocyte turnover were assessed immunohistochemically. Gene expression profiles were generated by extracting total RNA from the tissues and analyzing by microarray. Results The nitrative DNA lesions and the regenerative proliferation of hepatocytes were increased during the progression of chronic liver disease. In a gene expression profile analysis of liver samples, the chemokine- and T cell receptor (TCR)-mediated pathways were enhanced during chronic hepatitis, and the EGF- and VEGF-mediated pathways were induced in HCC. Among these molecules, the protein levels of STAT3 were greatly enhanced in all hepatocyte nuclei and further elevated in the cytoplasm in HCC tissue samples at 18 months, and the levels of phosphorylated TP53 (p-p53-Ser 6 and -Ser 15) were increased in liver tissues. Conclusions HBV-specific immune responses caused unique molecular signatures in the liver tissues of chronic hepatitis and triggered subsequent carcinogenic gene expression profiles in a mouse model. The results suggest a plausible molecular basis responsible for HBV-induced immune pathogenesis of HCC.


Endoscopy International Open | 2016

Preoperative diagnosis of cavernous hemangioma presenting with melena using wireless capsule endoscopy of the small intestine

Yu Akazawa; Katsushi Hiramatsu; Takuto Nosaka; Yasushi Saito; Yoshihiko Ozaki; Kazuto Takahashi; Tatsushi Naito; Kazuya Ofuji; Hidetaka Matsuda; Masahiro Ohtani; Tomoyuki Nemoto; Hiroyuki Suto; Akio Yamaguchi; Yoshiaki Imamura; Yasunari Nakamoto

Background and study aims: Primary neoplasms of the small intestine are relatively rare in all age groups, accounting for about 5 % of all gastrointestinal tumors 1. Cavernous hemangiomas of the small intestine are also rare, can cause gastrointestinal bleeding, and are extremely difficult to diagnose preoperatively 2. We present a patient who presented with melena and iron deficiency anemia, for whom wireless capsule endoscopy and single-balloon enteroscopy facilitated the diagnosis of cavernous hemangioma.


Diagnostic and Therapeutic Endoscopy | 2016

Long-Term Endoscopic Follow-Up of Patients with Chronic Radiation Proctopathy after Brachytherapy for Prostate Cancer

Masahiro Ohtani; Hiroyuki Suto; Takuto Nosaka; Yasushi Saito; Yoshihiko Ozaki; Ryoko Hayama; Tatsushi Naito; Kazuto Takahashi; Kazuya Ofuji; Hidetaka Matsuda; Katsushi Hiramatsu; Tomoyuki Nemoto; Hiroki Shioura; Hirohiko Kimura; Yoshitaka Aoki; Osamu Yokoyama; Yasunari Nakamoto

Background. Chronic radiation proctopathy (CRP) is late toxicity and associated with morbidity. Aim. To investigate the predictors of prognosis in patients with CRP after brachytherapy (BT). Methods. One hundred four patients with prostate cancer were treated with BT or BT followed by external-beam radiotherapy (BT + EBRT). We retrospectively investigated the 5-year incidence of rectal bleeding and endoscopic findings of CRP using the Vienna Rectoscopy Score (VRS). Twenty patients with VRS ≥ 1 were divided into the improved VRS group without treatment, unchanged VRS group, and treated group. The parameters associated with alteration of VRS were analyzed. Results. The incidence of rectal bleeding was 24%. The risk of rectal bleeding was higher in patients treated with BT + EBRT compared to those treated with BT (p < 0.0001). The incidence of superficial microulceration was higher in the improved VRS group than in the unchanged VRS group (p < 0.05). The incidence of multiple confluent telangiectasia or superficial ulcers > 1 cm2 was higher in the treated group than in both the improved and unchanged VRS groups (p < 0.05). Conclusions. Patients treated with BT + EBRT have a high risk of CRP. Endoscopic findings were useful for prognostic prediction of CRP.


BMC Cancer | 2015

Pituitary metastasis of hepatocellular carcinoma presenting with panhypopituitarism: a case report.

Tomoko Tanaka; Katsushi Hiramatsu; Takuto Nosaka; Yasushi Saito; Tatsushi Naito; Kazuto Takahashi; Kazuya Ofuji; Hidetaka Matsuda; Masahiro Ohtani; Tomoyuki Nemoto; Hiroyuki Suto; Tatsuya Yamamoto; Hirohiko Kimura; Yasunari Nakamoto

BackgroundMetastasis to the pituitary gland is extremely rare and is often detected incidentally by symptoms associated with endocrine dysfunction. Breast and lung cancer are the most common primary metastasizing to pituitary gland. Metastasis from hepatocellular carcinoma to the pituitary gland is extremely rare, with only 10 cases having been previously reported. We present here the first case of pituitary metastasis of hepatocellular carcinoma presenting with panhypopituitarism diagnosed by magnetic resonance imaging.Case presentationWe report the case of an 80-year-old Japanese woman who presented with the sudden onset of hypotension and bradycardia after having previously been diagnosed with hepatocellular carcinoma. Based on low levels of pituitary hormones, she was diagnosed with panhypopituitarism caused by metastasis of the hepatocellular carcinoma to the pituitary gland. Magnetic resonance imaging with arterial spin-labeling was effective in the differential diagnosis of the intrasellar tumor. The patient died despite hormone replacement therapy because of hypovolemic shock.ConclusionMetastasis to the pituitary gland causes various non-specific symptoms, so it is difficult to diagnose. The present case emphasizes the importance of diagnostic imaging in identifying these metastases. Clinicians should consider the possibility of pituitary metastasis in patients with malignant tumors who demonstrate hypopituitarism.


Journal of Medical Virology | 2018

Genetic polymorphism and decreased expression of HLA class II DP genes are associated with HBV reactivation in patients treated with immunomodulatory agents

Hidetaka Matsuda; Katsushi Hiramatsu; Yu Akazawa; Takuto Nosaka; Yasushi Saito; Yoshihiko Ozaki; Ryoko Hayama; Kazuto Takahashi; Tatsushi Naito; Kazuya Ofuji; Masahiro Ohtani; Tomoyuki Nemoto; Yukio Hida; Hideki Kimura; Yoshihiro Soya; Yasunari Nakamoto

Hepatitis B virus (HBV) reactivation can be triggered by immunosuppressive chemotherapy. HLA class II molecules may play a role in HBV reactivation. Genetic polymorphism and mRNA expression of HLA class II were examined in patients with latent HBV infection treated with immunosuppressive therapies. Subjects with resolved HBV infection who had undergone treatment with immunosuppressive chemotherapies were retrospectively enrolled (n = 42) and divided into reactivated (n = 9) and non‐reactivated groups (n = 33). Patients were genotyped for 17 single nucleotide polymorphisms (SNPs) within HLA class II DPA1, and DPB1, and mRNA expression levels of HLA class II genes were assessed. The frequency of the AA genotype of rs872956, a SNP in HLA‐DPB1, was significantly higher in the reactivated group than in the non‐reactivated group (55.6% vs 12.1%, P < 0.05). The frequencies of the T allele and non‐AA genotypes (AT/TT) of rs3116996 (located in DPB1) were significantly higher in the reactivated group (T allele frequency: 16.7% vs 0.0% [P < 0.01], non‐AA genotype frequency: 22.2% vs 0.0% [P < 0.05]). Multivariate logistic regression identified the AA genotype of rs872956 as an independent protective factor against HBV reactivation (odds ratio [OR] = 18.1, 95% confidence interval [CI] = 2.6‐126.7, P < 0.01). mRNA expression of HLA‐DPB1 was lower in the HBV reactivated group than in the non‐reactivated group (median 276.1 ± 165.6/β‐actin vs 371.4 ± 407.5/β‐actin [P < 0.05]). These results suggest the involvement of HLA class II molecules in HBV reactivation after treatment with immunomodulatory agents.


Journal of Digestive Diseases | 2018

Long-term prognosis after biliary stenting for common bile duct stones in high-risk elderly patients: Biliary stenting in high-risk elderly patients

Yu Akazawa; Masahiro Ohtani; Takuto Nosaka; Yasushi Saito; Kazuto Takahashi; Tatsushi Naito; Kazuya Ofuji; Hidetaka Matsuda; Katsushi Hiramatsu; Tomoyuki Nemoto; Yasunari Nakamoto

To evaluate the long‐term outcomes of complete common bile duct (CBD) stone removal and biliary stenting in elderly patients (≥85 years) with CBD stones.


Endoscopy International Open | 2018

Duplication cyst of the ileum presenting with severe anemia detected by double-balloon endoscopy

Yumi Takegawa; Katsushi Hiramatsu; Yosuke Murata; Yu Akazawa; Yasushi Saito; Yoshihiko Ozaki; Kazuto Takahashi; Tatsushi Naito; Kazuya Ofuji; Hidetaka Matsuda; Masahiro Ohtani; Tomoyuki Nemoto; Hiroyuki Suto; Takanori Goi; Yoshiaki Imamura; Yasunari Nakamoto

Background and study aims  Duplication cysts of the ileum are rare and present with non-specific clinical manifestations such as abdominal pain, vomiting, melena, and intussusception. Therefore, preoperative diagnosis is difficult. Here, we report a case of duplication cyst of the small intestine that was diagnosed preoperatively using double-balloon enteroscopy. A 19-year-old man presented with severe iron deficiency anemia, abdominal pain, and exertional dyspnea. Gastroscopy and colonoscopy revealed no remarkable findings. Abdominal computed tomography revealed a cystic structure in the ileum. Therefore, we performed double-balloon enteroscopy via the anal route. The intestinal tract was bifurcated, with one segment ending in a blind sac containing normal villi and an ulceration. Tc-99 m pertechnetate scintigraphy showed no accumulation in the lesion. Accordingly, we diagnosed a duplication cyst and suspected that this was the cause of severe anemia. Following small bowel resection with cyst excision and anastomosis, the anemia and presenting symptoms resolved. This report highlights the usefulness of double-balloon enteroscopy of the small intestine for preoperative diagnosis of the obscure gastrointestinal bleeding, including duplication cysts .


Journal of Medical Virology | 2017

Identification of novel variants in HLA class II region related to HLA DPB1 expression and disease progression in patients with chronic hepatitis C

Katsushi Hiramatsu; Hidetaka Matsuda; Tomoyuki Nemoto; Takuto Nosaka; Yasushi Saito; Tatsushi Naito; Kazuto Takahashi; Kazuya Ofuji; Masahiro Ohtani; Hiroyuki Suto; Toshihiro Yasuda; Yukio Hida; Hideki Kimura; Yoshihiro Soya; Yasunari Nakamoto

Recent genome‐wide studies have demonstrated that HLA class II gene may play an important role in viral hepatitis. We studied genetic polymorphism and RNA expression of HLA class II genes in HCV‐related liver diseases. The study was performed in groups consisting of 24 patients with HCV‐related liver disease (12 of persistent normal ALT: PNALT group and 12 of advanced liver disease: ALD group) and 26 patients without HCV infection (control group). In PBMC samples, RNA expression of HLA class II genes (HLA‐DPA1, DPB1, DQA1, DQB1, and DRB1) was analyzed by real‐time RT‐PCR. Furthermore, 22 single nucleotide polymorphisms (SNPs) in HLA class II gene and two SNPs in IL28B gene were genotyped by genetic analyzer (GENECUBE®). In expression analysis, only DPB1 level was significantly different. Mean expression level of DPB1gene in control group was 160.0, PNALT group 233.8, and ALD group 465.0 (P < 0.01). Of 24 SNPs, allele frequencies were statistically different in two SNPs (rs2071025 and rs3116996) between PNALT groups and ALD group (P < 0.01). In rs2071025, TT genotype was frequently detected in ALD group and expression level was significantly higher than the other genotypes (449.2 vs 312.9, P < 0.01). In rs3116996, TA or TT (non AA) genotype was frequently detected in ALD group and expression level was significantly higher than genotype AA (457.1 vs 220.9, P < 0.01). Genotyping and expression analysis in HLA class II gene revealed that two SNPs of HLA‐DPB1 (rs2071025 and rs3116996) were significantly correlated to RNA expression and progression of HCV‐related liver diseases.

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