Hiroyuki head and Yamada

Prof. Hiroyuki head and Yamada


Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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MYMasaaki Yasukawa
Masaaki Yasukawa
HFHisako Fujihara
Hisako Fujihara
HFHiroaki Fujimori
Hiroaki Fujimori
KKKoji Kawaguchi
Koji Kawaguchi
HYHiroyuki head and Yamada
Hiroyuki head and Yamada
MMMitsuko Masutani
Mitsuko Masutani
Cisplatin is a commonly used chemotherapeutic drug for treatment of oral carcinoma, and combinatorial effects are expected to exert greater therapeutic efficacy compared with monotherapy. Poly(ADP-ribosyl)ation is reported to be involved in a variety of cellular processes, such as DNA repair, cell death, telomere regulation, and genomic stability. Based on these properties, poly(ADP-ribose) polymerase (PARP) inhibitors are used for treatment of cancers, such as BRCA1/2 mutated breast and ovarian cancers, or certain solid cancers in combination with anti-cancer drugs. However, the effects on oral cancer have not been fully evaluated. In this study, we examined the effects of PARP inhibitor on the survival of human oral cancer cells in vitro and xenografted tumors derived from human oral cancer cells in vivo. In vitro effects were assessed by microculture tetrazolium and survival assays. The PARP inhibitor AZD2281 (olaparib) showed synergetic effects with cisplatin in a dose-dependent manner. Combinatorial treatment with cisplatin and AZD2281 significantly inhibited xenografted tumor growth compared with single treatment of cisplatin or AZD2281. Histopathological analysis revealed that cisplatin and AZD2281 increased TUNEL-positive cells and decreased Ki67- and CD31-positive cells. These results suggest that PARP inhibitors have the potential to improve therapeutic strategies for oral cancer.

17 April 2018 in The Journal of Dermatology
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HNHidemi Nakagawa
Hidemi Nakagawa
ONOsamu Nemoto
Osamu Nemoto
HYHiroyuki Yamada
Hiroyuki Yamada
TNTakeshi Nagata
Takeshi Nagata
NNNoriko Ninomiya
Noriko Ninomiya
The purpose of the present two phase 1 studies was to assess the safety, tolerability and pharmacokinetics for topical application of a novel Janus kinase (JAK) inhibitor, JTE‐052, in Japanese healthy adult male volunteers and Japanese adult patients with atopic dermatitis (AD). Additionally, exploratory investigation was performed on the efficacy for disease severity and pruritus score in AD patients. In the QBX1‐1 study, the cutaneous safety of JTE‐052 ointment by a patch test and a photo patch test was assessed in an intra‐individual comparative study using placebo ointment, white petrolatum and non‐application as comparators. The study demonstrated that JTE‐052 ointment would be associated with a low potential for phototoxicity but had no potential for skin irritation or photoallergy. In the QBX1‐2 study, it was revealed that the systemic exposure to JTE‐052 in both healthy volunteers with normal skin and AD patients with inflamed skin was low in application of not only 1% but also 3% JTE‐052 ointment. JTE‐052 ointments of 1% and 3% were generally safe and well tolerated in both populations. In a repeated twice‐daily application for 7 days, the efficacy of JTE‐052 ointment to AD patients was observed with both 1% and 3% ointments in the exploratory investigations evaluated by Eczema Area and Severity Index, Investigator's Global Assessment and Numeric Rating Scale assessments. The mean scores for each assessment declined from the baseline throughout the study. These results suggest that the treatment of JTE‐052 ointment is generally safe and effective in AD patients, although further large confirmatory studies are needed.

14 October 2021 in Journal of Clinical Medicine
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IMIkuya Miyamoto
Ikuya Miyamoto
RTRyoichi Tanaka
Ryoichi Tanaka
SKShintaro Kogi
Shintaro Kogi
GYGenki Yamaya
Genki Yamaya
TKTadashi Kawai
Tadashi Kawai
HYHiroyuki head and Yamada
Hiroyuki head and Yamada
Radiation therapy (RT) plays a significant role in the management of head and neck malignancies. This study aimed to review the clinical symptoms and various imaging findings of osteoradionecrosis (ORN) and provide a clinical perspective on the development of ORN. The retrospective cohort was composed of 57 sites in 54 patients who had a history of RT and suspected ORN and 48 sites in 45 patients who were confirmed to have ORN. Image analyses included computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET)/CT, bone scintigraphy, and single-photon emission CT (SPECT). The irradiated tissue was damaged by RT, and the extent of damage was correlated with clinical symptoms. The bone marrow showed sclerotic changes and the devitalized bone showed bone resorption after invasive stimulation. Chronic trismus and pathological fracture are considered severe conditions, typically occurring in the last stage of ORN. Furthermore, neurological symptoms were an important sign of tumor recurrence, since diagnostic imaging was difficult. The possible treatment options vary depending on the stage of ORN. We speculate that bone sclerosis reactions and bone resorption are sequential reactions that seem to be protective measures of the bone to radiation injury.

13 May 2022 in Cancers
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AOAiri Ota
Airi Ota
IMIkuya Miyamoto
Ikuya Miyamoto
YOYu Ohashi
Yu Ohashi
Toshimi ChibaToshimi Chiba
Toshimi Chiba
YTYasunori Takeda
Yasunori Takeda
HYHiroyuki head and Yamada
Hiroyuki head and Yamada
This study aimed to clarify the advantages and disadvantages of conventional visual inspection (CVI), endoscopic white light imaging (WLI), and narrow-band imaging (NBI) and to examine the diagnostic accuracy of intraepithelial papillary capillary loops (IPCL) for the detection of oral squamous cell carcinoma (OSCC). This cross-sectional study included 60 participants with oral mucosal diseases suspected of having oral potentially malignant disorders (OPMDs) or OSCC. The patients underwent CVI, WLI, NBI, and incisional biopsy. Images were evaluated to assess the lesion size, color, texture, and IPCL. Oral lichen planus (OLP) and oral leukoplakia lesions were observed in larger areas with NBI than with WLI; 75.0% were associated with low-grade (Type 0–II) IPCL. Various types of oral leukoplakia were seen; however, all OSCC cases showed high-grade (Type III–IV) IPCL. The diagnostic accuracy of high-grade IPCL for OSCC showed a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 100%, 80.9%, 59.1%, 100%, and 85.0%, respectively. A non-homogeneous lesion with high-grade IPCL strongly suggested malignancy. Overall, our results indicate that WLI and NBI are powerful tools for detecting precancerous and cancerous lesions using IPCL. However, NBI is influenced by mucosal thickness; therefore, image interpretation is important for accurate diagnosis.

31 January 2023 in Journal of Clinical Medicine
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KOKei Onodera
Kei Onodera
IMIkuya Miyamoto
Ikuya Miyamoto
IHIsao Hoshi
Isao Hoshi
SKShinsuke Kawamata
Shinsuke Kawamata
NTNoriaki Takahashi
Noriaki Takahashi
HYHiroyuki head and Yamada
Hiroyuki head and Yamada
The purpose of this retrospective study was to evaluate computer-assisted virtual surgery and the outcomes of mandibular reconstruction using an autogenous particulate cancellous bone and marrow (PCBM) graft combined with a custom-made titanium mesh (TiMesh) using a three-dimensional (3D) printing model. Eighteen consecutive patients were included, and preoperative virtual simulation surgery was performed using digital data. Segmental bone defects showed deviation of the mandible due to displacement of the condyle and segments, unnatural length of the mandibular body, or poorer intermaxillary relationship compared to the marginal bone defect caused by previous operations. These mandibular disharmonies could be simulated, and virtual surgery was performed on a computer with adjustment of displaced mandibular segments, length of the mandibular body, and dental arch with digital bone augmentation. TiMesh was manually pre-bent using a 3D printing model, and PCBM from the iliac crest was grafted with TiMesh. The short-term clinical results were good; reconstruction of the alveolar crest was prosthetically desirable; and minor complications were observed. In conclusion, virtual reconstruction is crucial for treating complex deviated mandibles. Accurate condylar and dental arch positions with an optimum mandibular length are important for prosthetically satisfactory mandibular reconstruction.

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KKKenichi Kumagai
Kenichi Kumagai
THTatsuya Horikawa
Tatsuya Horikawa
HSHiroaki Shigematsu
Hiroaki Shigematsu
RMRyota Matsubara
Ryota Matsubara
KKKazutaka Kitaura
Kazutaka Kitaura
SRSuzuki Ryuji
Suzuki Ryuji
Metal often causes delayed-type hypersensitivity reactions, which are possibly mediated by accumulating T cells in the inflamed skin, called irritant or allergic contact dermatitis. However, accumulating T cells during development of a metal allergy are poorly characterized because a suitable animal model is unavailable. We have previously established novel murine models of metal allergy and found accumulation of both metal-specific T cells and natural killer (NK) T cells in the inflamed skin. In our novel models of metal allergy, skin hypersensitivity responses were induced through repeated sensitizations by administration of metal chloride and lipopolysaccharide into the mouse groin followed by metal chloride challenge in the footpad. These models enabled us to investigate the precise mechanisms of the immune responses of metal allergy in the inflamed skin. In this review, we summarize the immune responses in several murine models of metal allergy and describe which antigen-specific responses occur in the inflamed skin during allergic contact dermatitis in terms of the T cell receptor. In addition, we consider the immune regulation of accumulated NK T cells in metal ion–induced allergic contact dermatitis.