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Featured researches published by Kenji Hirayama.


Human Immunology | 1988

Immune suppression gene on HLA-Bw54-DR4-DRw53 haplotype controls nonresponsiveness in humans to hepatitis B surface antigen via CD8+ suppressor T cells

Hiroshi Watanabe; Sho Matsushita; Nobuhiro Kamikawaji; Kenji Hirayama; Makoto Okumura; Takehiko Sasazuki

The development of antiviral vaccines has been accelerated using monoclonal antibody and/or recombinant DNA techniques, the objective being to prevent grave viral infectious diseases, such as acquired immunodeficiency syndrome (AIDS), adult T-cell leukemia (ATL), and hepatitis B virus (HBV)-associated liver diseases. Certain proportions of individuals in the human population do not have any appreciable immune response to foreign antigens, either in cases of natural exposure or a planned immunization. Here we report that in the nonresponders to HB vaccine, there is an HLA-linked immune suppression gene for hepatitis B surface antigen (Is-HBsAg) controlling the nonresponsiveness to HBsAg through HBsAg-specific suppressor T cells. The Is-HBsAg is in strong linkage disequilibrium with the HLA-Bw54-DR4-DRw53 haplotype.


Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine | 2014

Monitoring Sound To Quantify Snoring and Sleep Apnea Severity Using a Smartphone: Proof of Concept

Hiroshi Nakano; Kenji Hirayama; Yumiko Sadamitsu; Ayaka Toshimitsu; Hisayuki Fujita; Shizue Shin; Takeshi Tanigawa

STUDY OBJECTIVES Habitual snoring is a prevalent condition that is not only a marker of obstructive sleep apnea (OSA) but can also lead to vascular risk. However, it is not easy to check snoring status at home. We attempted to develop a snoring sound monitor consisting of a smartphone alone, which is aimed to quantify snoring and OSA severity. METHODS The subjects included 50 patients who underwent diagnostic polysomnography (PSG), of which the data of 10 patients were used for developing the program and that of 40 patients were used for validating the program. A smartphone was attached to the anterior chest wall over the sternum. It acquired ambient sound from the built-in microphone and analyzed it using a fast Fourier transform on a real-time basis. RESULTS Snoring time measured by the smartphone highly correlated with snoring time measured by PSG (r = 0.93). The top 1 percentile value of sound pressure level (L1) determined by the smartphone correlated with the ambient sound L1 during sleep determined by PSG (r = 0.92). Moreover, the respiratory disturbance index estimated by the smartphone (smart-RDI) highly correlated with the apnea-hypopnea index (AHI) obtained by PSG (r = 0.94). The diagnostic sensitivity and specificity of the smart-RDI for diagnosing OSA (AHI ≥ 15) were 0.70 and 0.94, respectively. CONCLUSIONS A smartphone can be used for effectively monitoring snoring and OSA in a controlled laboratory setting. Use of this technology in a noisy home environment remains unproven, and further investigation is needed.


Human Immunology | 1989

Activation of human CD8+ suppressor T cells by an antigen-specific CD4+ T-cell line in vitro.

Mitsuru Fukunaga; Kenji Hirayama; Takehiko Sasazuki

We generated an antigen (streptococcal cell wall antigen)-specific T-cell line from peripheral blood mononuclear cells of a healthy donor with an intermediate response to streptococcal cell wall antigen. Proliferation of the T-cell line was completely blocked by a monoclonal antibody to HLA-DR. This line activated autologous CD8+ T cells in an antigen-specific manner in the presence of autologous monocytes. This activation was mediated by a factor derived from this line and was blocked by a monoclonal antibody against HLA class I molecules. The resultant CD8+ T blasts showed antigen-nonspecific suppression but no cytolytic activity. This antigen-specific generation of the CD8+ T-cell line in vitro by the antigen-specific CD4+ T-cell line is expected to contribute to analyses of functions of CD8+ T-cell subsets, particularly in the down-regulating system, at both cellular and molecular levels.


Sleep | 2013

Mean tracheal sound energy during sleep is related to daytime blood pressure.

Hiroshi Nakano; Kenji Hirayama; Yumiko Sadamitsu; Shizue Shin; Tomoaki Iwanaga

STUDY OBJECTIVES The pathological role of snoring independent of obstructive sleep apnea remains under debate. The authors hypothesized that snoring sound intensity, as assessed by mean tracheal sound energy (Leq) during sleep, is related to daytime blood pressure. DESIGN Retrospective analysis of clinical records and polysomnography data. SETTING Sleep laboratory at a national hospital in Japan. PATIENTS Consecutive patients who underwent diagnostic polysomnography with suspicion of sleep apnea between January 2005 and December 2009 (n = 1,118). INTERVENTIONS Not applicable. MEASUREMENTS AND RESULTS Leq was calculated from tracheal sound spectra recorded every 0.2 sec during polysomnography. Daytime high blood pressure (HBP) was defined as taking antihypertensive drugs or having a systolic blood pressure ≥ 140 mm Hg or a diastolic blood pressure ≥ 90 mmHg at the patients first clinical visit. Patient age, sex, body mass index, apnea-hypopnea index, alcohol consumption, and smoking were considered as confounders. Leq during sleep was associated with HBP after adjusting for all confounding factors (n = 1,074, P = 0.00019). This association was demonstrated even in nonapneic nonobese patients (n = 232, P = 0.012). CONCLUSIONS The association between snoring intensity, as assessed by mean sound energy, and blood pressure suggests a pathological role for heavy snoring. Further study in a general population is warranted.


Modern Rheumatology | 2001

Primary Sjögren's syndrome complicated by sarcoidosis and psoriasis vulgaris

Kenji Hirayama; Satoshi Shiokawa; Yoshitaka Miyazaki; Michihiro Nakamura; Seiichi Motomura; Youko Suehiro; Yasuji Yoshikawa; Shoichiro Ikuyama; Junji Nishimura

Abstract Primary Sjögrens syndrome (SS), sarcoidosis (SA), and psoriasis vulgaris (PV) are all chronic diseases of unknown etiology. Recent studies suggest that activated T cells play a central role in their pathogenesis. We describe a case of a Japanese woman with primary SS complicated by SA and PV. To our knowledge, this is the first case in which these three diseases coexist. Although these three disorders may have a common immunopathogenic mechanism, the extreme rarity of their coexistence suggests that distinct etiological mechanisms are also involved and appear to play an important role in triggering and developing each disease.


Tissue Antigens | 1990

HLA-Bw54-DR4-DRw53-DQw4 haplotype controls nonresponsiveness to hepatitis-B surface antigen via CD8-positive suppressor T cells

Hiroshi Watanabs; Makoto Okumura; Kenji Hirayama; Takehike Sasazuki


The New England Journal of Medicine | 1988

Cushing's syndrome due to ectopic ACTH secretion by bilateral pheochromocytomas in multiple endocrine neoplasia type 2A.

Koji Honda; Kenji Hirayama; Ikuo Kikuchi; Hiroshi Nagato; Hajime Tamai; Takehiko Sasazuki


Leprosy Review | 1986

An HLA-linked gene controls susceptibility to lepromatous leprosy through T cell regulation

Ikuo Kikuchi; T. Ozawa; Kenji Hirayama; Takehiko Sasazuki


European Journal of Pharmacology | 2003

Endogenous glucocorticoids inhibit scratching behavior induced by the administration of compound 48/80 in mice.

Kenji Hirayama; Nobuyuki Sudo; Masanori Sueyasu; Junko Sonoda; Youich Chida; Ryozo Oishi; Chiharu Kubo


Sleep and Biological Rhythms | 2010

Relationship between snoring sound intensity and daytime blood pressure

Tomokazu Furukawa; Hiroshi Nakano; Kenji Hirayama; Tokusei Tanahashi; Kazufumi Yoshihara; Nobuyuki Sudo; Chiharu Kubo; Sankei Nishima

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