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Dive into the research topics where Masafumi Mizooka is active.

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Featured researches published by Masafumi Mizooka.


BMJ Open | 2013

Diagnostic workup for fever of unknown origin: a multicenter collaborative retrospective study.

Toshio Naito; Masafumi Mizooka; Fujiko Mitsumoto; Kenji Kanazawa; Keito Torikai; Shiro Ohno; Hiroyuki Morita; Akira Ukimura; Nobuhiko Mishima; Fumio Otsuka; Yoshio Ohyama; Noriko Nara; Kazunari Murakami; Kouichi Mashiba; Kenichiro Akazawa; Koji Yamamoto; Shoichi Senda; Masashi Yamanouchi; Susumu Tazuma; Jun Hayashi

Objective Fever of unknown origin (FUO) can be caused by many diseases, and varies depending on region and time period. Research on FUO in Japan has been limited to single medical institution or region, and no nationwide study has been conducted. We identified diseases that should be considered and useful diagnostic testing in patients with FUO. Design A nationwide retrospective study. Setting 17 hospitals affiliated with the Japanese Society of Hospital General Medicine. Participants This study included patients ≥18 years diagnosed with ‘classical fever of unknown origin’ (axillary temperature ≥38°C at least twice over a ≥3-week period without elucidation of a cause at three outpatient visits or during 3 days of hospitalisation) between January and December 2011. Results A total of 121 patients with FUO were enrolled. The median age was 59 years (range 19–94 years). Causative diseases were infectious disease in 28 patients (23.1%), non-infectious inflammatory disease in 37 (30.6%), malignancy in 13 (10.7%), other in 15 (12.4%) and unknown in 28 (23.1%). The median interval from fever onset to evaluation at each hospital was 28 days. The longest time required for diagnosis involved a case of familial Mediterranean fever. Tests performed included blood cultures in 86.8%, serum procalcitonin in 43.8% and positron emission tomography in 29.8% of patients. Conclusions With the widespread use of CT, FUO due to deep-seated abscess or solid tumour is decreasing markedly. Owing to the influence of the ageing population, polymyalgia rheumatica was the most frequent cause (9 patients). Four patients had FUO associated with HIV/AIDS, an important cause of FUO in Japan. In a relatively small number of cases, cause remained unclear. This may have been due to bias inherent in a retrospective study. This study identified diseases that should be considered in the differential diagnosis of FUO.


Hepatology Research | 2015

Clinical evaluation of ezetimibe on bile lithogenicity in humans: Use of transnasal endoscopy for bile sampling.

Nobusuke Kishikawa; Keishi Kanno; Akiko Sugiyama; Kenichi Yokobayashi; Masafumi Mizooka; Susumu Tazuma

Ezetimibe inhibits cholesterol absorption by blocking Niemann–Pick C1‐like 1 proteins (NPC1L1) expressed in the small intestine. Because NPC1L1 is also expressed in human liver, ezetimibe conceivably alters biliary lipid compositions. Here, we performed a clinical trial investigating the effect of ezetimibe on biliary lipids using transnasal endoscopy for bile collection.


Journal of Hepato-biliary-pancreatic Sciences | 2016

Practice Guidelines for Primary Care of Acute Abdomen 2015

Toshihiko Mayumi; Masahiro Yoshida; Susumu Tazuma; Akira Furukawa; Osamu Nishii; Kunihiro Shigematsu; Takeo Azuhata; Atsuo Itakura; Seiji Kamei; Hiroshi Kondo; Shigenobu Maeda; Hiroshi Mihara; Masafumi Mizooka; Toshihiko Nishidate; Hideaki Obara; Norio Sato; Yuichi Takayama; Tomoyuki Tsujikawa; Tomoyuki Fujii; Tetsuro Miyata; Izumi Maruyama; Hiroshi Honda; Koichi Hirata

Since acute abdomen requires accurate diagnosis and treatment within a particular time limit to prevent mortality, the Japanese Society for Abdominal Emergency Medicine, in collaboration with four other medical societies, launched the Practice Guidelines for Primary Care of Acute Abdomen that were the first English guidelines in the world for the management of acute abdomen. Here we provide the highlights of these guidelines (all clinical questions and recommendations were shown in supplementary information). A systematic and comprehensive evaluation of the evidence for epidemiology, diagnosis, differential diagnosis, and primary treatment for acute abdomen was performed to develop the Practice Guidelines for Primary Care of Acute Abdomen 2015. Because many types of pathophysiological events underlie acute abdomen, these guidelines cover the primary care of adult patients with nontraumatic acute abdomen. A total of 108 questions based on nine subject areas were used to compile 113 recommendations. The subject areas included definition, epidemiology, history taking, physical examination, laboratory test, imaging studies, differential diagnosis, initial treatment, and education. Japanese medical circumstances were considered for grading the recommendations to assure useful information. The two‐step methods for the initial management of acute abdomen were proposed. Early use of transfusion and analgesia, particularly intravenous acetaminophen, were recommended. The Practice Guidelines for Primary Care of Acute Abdomen 2015 have been prepared as the first evidence‐based guidelines for the management of acute abdomen. We hope that these guidelines contribute to clinical practice and improve the primary care and prognosis of patients with acute abdomen.


Japanese Journal of Radiology | 2016

The Practice Guidelines for Primary Care of Acute Abdomen 2015

Toshihiko Mayumi; Masahiro Yoshida; Susumu Tazuma; Akira Furukawa; Osamu Nishii; Kunihiro Shigematsu; Takeo Azuhata; Atsuo Itakura; Seiji Kamei; Hiroshi Kondo; Shigenobu Maeda; Hiroshi Mihara; Masafumi Mizooka; Toshihiko Nishidate; Hideaki Obara; Norio Sato; Yuichi Takayama; Tomoyuki Tsujikawa; Tomoyuki Fujii; Tetsuro Miyata; Izumi Maruyama; Hiroshi Honda; Koichi Hirata

BackgroundSince acute abdomen requires accurate diagnosis and treatment within a particular time limit to prevent mortality, the Japanese Society for Abdominal Emergency Medicine in collaboration with four other medical societies launched the Practice Guidelines for Primary Care of Acute Abdomen that were the first English guidelines in the world for the management of acute abdomen. Here we provide the highlights of these guidelines [all clinical questions (CQs) and recommendations are shown in supplementary information].MethodsA systematic and comprehensive evaluation of the evidence for epidemiology, diagnosis, differential diagnosis, and primary treatment for acute abdomen was performed to develop the Practice Guidelines for Primary Care of Acute Abdomen 2015. Because many types of pathophysiological events underlie acute abdomen, these guidelines cover the primary care of adult patients with nontraumatic acute abdomen.ResultsA total of 108 questions based on 9 subject areas were used to compile 113 recommendations. The subject areas included definition, epidemiology, history taking, physical examination, laboratory test, imaging studies, differential diagnosis, initial treatment, and education. Japanese medical circumstances were considered for grading the recommendations to assure useful information. The two-step methods for the initial management of acute abdomen were proposed. Early use of transfusion and analgesia, particularly intravenous acetaminophen, were recommended.ConclusionsThe Practice Guidelines for Primary Care of Acute Abdomen 2015 have been prepared as the first evidence-based guidelines for the management of acute abdomen. We hope that these guidelines contribute to clinical practice and improve the primary care and prognosis of patients with acute abdomen.


Journal of General and Family Medicine | 2017

General practice departments of university hospitals and certified training programs for general practitioners in Japan: A nationwide questionnaire survey

Masatoshi Matsumoto; Masafumi Mizooka; Susumu Tazuma

In the reform of specialist training by Japanese Medical Specialty Board, general practice is expected to be one of 19 core specialties. University departments of general practice can play a central role in training board‐certified generalists, but whether they are actually preparing to do so is unknown.


Journal of General and Family Medicine | 2017

Key diagnostic features of fever of unknown origin: Medical history and physical findings

Rinne Takeda; Masafumi Mizooka; Tomoki Kobayashi; Nobusuke Kishikawa; Kenichi Yokobayashi; Keishi Kanno; Susumu Tazuma

Fever of unknown origin (FUO) has many possible causes, so detailed history taking and physical examination are required. We identified key diagnostic features of medical history and physical findings for an efficient diagnosis of FUO.


Journal of Hepato-biliary-pancreatic Sciences | 2016

Long -term administration of a Niemann -Pick C1 -like 1 inhibitor, ezetimibe, does not worsen bile lithogenicity in dyslipidemic patients with hepatobiliary diseases

Nobusuke Kishikawa; Keishi Kanno; Akiko Sugiyama; Kenichi Yokobayashi; Masafumi Mizooka; Susumu Tazuma

Certain lipid‐lowering drugs increase bile lithogenicity. Here we investigated whether long‐term administration of ezetimibe, a new class of hypocholesterolemic agents designed to inhibit intestinal cholesterol absorption by inhibiting Niemann‐Pick C1‐like 1, alters bile lithogenicity in patients with hepatobiliary diseases.


Internal Medicine | 2018

Five Cases of Familial Mediterranean Fever in Japan: The Relationship with MEFV Mutations

Kazuki Kimura; Masafumi Mizooka; Kiyoshi Migita; Ryoko Ishida; Masatoshi Matsumoto; Satoshi Yamasaki; Nobusuke Kishikawa; Akihiro Kawahara; Yuka Kikuchi; Yuichiro Otani; Tomoki Kobayashi; Daisuke Miyamori; Takuya Ikuta; Hiroshi Nakamura; Kenichi Yokobayashi; Shuichi Iwamoto; Keishi Kanno; Hiromasa Ohira; Susumu Tazuma

Familial Mediterranean fever (FMF) is the most common genetic autoinflammatory disease, but it has been considered a rare disease in Japan. We herein describe five patients with FMF who were diagnosed both clinically and genetically at a single Japanese institute. A genetic investigation of Mediterranean fever (MEFV) detected heterozygosity for the compound mutations L110P/E148Q (n=2) and L110P/148Q/P369S/R406Q (n=1), and heterozygosity for M694I (n=1) and S503C (n=1). Colchicine prevented febrile attacks and accompanying symptoms in four patients. One patient with an S503C mutation showed resistance. Physicians should be aware of the characteristic symptoms, as well as the more unusual symptoms such as headache, when diagnosing FMF.


Case Reports in Medicine | 2018

Primary Signet Ring Cell Carcinoma of Rectum Diagnosed by Boring Biopsy in Combination with Endoscopic Mucosal Resection

Yoshito Hirata; Keishi Kanno; Nobusuke Kishikawa; Shinji Tomoda; Kazuki Kimura; Tomoki Kobayashi; Daisuke Miyamori; Yuichiro Otani; Masafumi Mizooka; Koji Arihiro; Shiro Oka; Shinji Tanaka; Susumu Tazuma

A 46-year-old man with severe back pain visited our hospital. Magnetic resonance imaging revealed extensive bone metastasis and rectal wall thickness. Colonoscopy revealed circumferential stenosis with edematous mucosa, suggesting colon cancer. However, histological findings of biopsy specimens revealed inflammatory cells but no malignant cells. The patient underwent endoscopic ultrasound, which demonstrated edematous wall thickness without destruction of the normal layer structure. After unsuccessful detection of neoplastic cells by boring biopsies, we performed endoscopic mucosal resection followed by boring biopsies that finally revealed signet ring cell carcinoma. Herein, we present a case and provide a review of the literature.


Internal Medicine | 2016

Systemic Inflammatory Syndrome Associated with a Case of Jugular Paraganglioma.

Ayuko Sokabe; Masafumi Mizooka; Rinne Sakemi; Tomoki Kobayashi; Nobusuke Kishikawa; Kenichi Yokobayashi; Keishi Kanno; Susumu Tazuma

Jugular paraganlioma is a benign, slow-growing tumor originating from the paraganglion cells and it is associated with catecholamine secretion. Paragangliomas can secrete Interleukin-6 (IL-6) and present as a systemic inflammatory syndrome; these characteristics have not been previously associated with jugular paragangliomas. A 63-year-old man with a jugular tumor in the skull base was referred to our hospital for an evaluation of pyrexia, back pain, and acute inflammation. His serum IL-6 level was elevated on admission and it decreased after radiotherapy. This is the first known case of a jugular paraganglioma exhibiting systemic inflammatory syndrome.

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Reiko Yamamoto

Jichi Medical University

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Akira Furukawa

Tokyo Metropolitan University

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