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Dive into the research topics where Atsushi Sakakura is active.

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Featured researches published by Atsushi Sakakura.


Journal of Voice | 1996

Perceived pitch of whispered vowels-relationship with formant frequencies: A preliminary study

Masahiko Higashikawa; Ken Nakai; Atsushi Sakakura; Hiroaki Takahashi

To clarify the role of formant frequency in the perception of pitch in whispering, we conducted a preliminary experiment to determine (1.) whether speakers change their pitch during whispering; (2.) whether listeners can perceive differences in pitch; and (3.) what the acoustical features are when speakers change their pitch. The listening test of whispered Japanese speech demonstrates that one can determine the perceived pitch of vowel /a/ as ordinary, high, or low. Acoustical analysis revealed that the perception of pitch corresponds to some formant frequencies. Further data with synthesized whispered voice are necessary to confirm the importance of the formant frequencies in detail for perceived pitch of whispered vowels.


Journal of Laryngology and Otology | 1996

Recurrent laryngeal papillomatosis developing into laryngeal carcinoma with human papilloma virus (HPV) type 18 : a case report

Atsushi Sakakura; Yuzo Yamamoto; Tomohiko Takasaki; Kazuo Makimoto; Masahiro Nakamura; Hiroaki Takahashi

We report a case of recurrent laryngeal papillomatosis which developed into laryngeal squamous cell carcinoma 11 years after the first diagnosis. Interestingly, we could identify HPV type 18 DNA in the carcinoma tissue using the polymerase chain reaction (PCR). Other known risk factors of irradiation, smoking, exposure to chemical agents, or a hereditary tendency to malignant tumours were not present in this case. Our finding suggests that HPV type 18 is another aetiological agent for laryngeal carcinoma.


European Archives of Oto-rhino-laryngology | 1996

Articulation after uvulopalatopharyngoplasty.

Ken Nakai; Atsushi Sakakura; Hiroaki Takahashi; Tatsuya Sadaoka; Noriya Kakitsuba

We performed perceptual and acoustic studies to demonstrate articulation after uvulopalatopharyngoplasty (UPPP) in Japanese patients at 28.6 days (mean) after surgery (range 21–50 days). The results of listening tests showed that there were no significant changes between pre- and postoperative articulation scores for any of 25 monosyllables tested, and there were no significant changes in the timbres of 5 Japanese vowels after UPPP. In the acoustic study of the first and second formant frequencies of the vowels, some formant frequencies had significant changes after UPPP. However, these changes in formants fell within the range of intraindividual variation. In the acoustic study of /ka/ with a palatal plosive /k/, there was no significant change in the voice onset time or F2 transition after UPPP.


Operations Research Letters | 1998

Three-Dimensional Imaging of Laryngeal Cancers Using High-Speed Helical CT Scanning

Atsushi Sakakura; Yuzo Yamamoto; Yasuo Uesugi; Ken Nakai; Hiroshi Takenaka; Isamu Narabayashi

To evaluate the clinical usefulness and limitations of three-dimensional (3-D) imaging of laryngeal cancers by high-speed helical (spiral) CT scanning, 3-D images were reconstructed for one dissected human larynx and 10 patients with laryngeal cancer. The larynges were scanned in 1- to 2-mm slices, and were reconstructed using a slice thickness of 0.5–1.0 mm. The macroscopic (or endoscopic) findings and the 3-D CT images of the larynx were compared. The selected threshold CT values were –600 HU (Hounsfield units) to –100 HU for the mucous membranes, and 250 HU for bone. Under these conditions, almost all of the structures remained distinct. The 3-D images of the larynx obtained by helical CT were very helpful in understanding laryngeal anatomy, especially in the subglottic area, which cannot be seen clearly by endoscopy or conventional axial CT. Clinically, this system would have advantages in the detection of subglottic cancers, or the invasion of glottic or supraglottic cancers into the subglottic area.


Auris Nasus Larynx | 1997

Prognostic value of nucleolar organizer regions in supraglottic carcinoma

Yuzo Yamamoto; Takashi Itoh; Tetsuro Saka; Atsushi Sakakura; Hiroaki Takahashi

The relationship of nucleolar organizer regions (NORs) to proliferative activity and tumor progression was studied in 16 supraglottic carcinomas. The number of NORs stained by a silver colloid staining method (AgNOR staining method) was determined. The mean AgNOR number tended to be higher (but not significantly so) in poorly differentiated tumors. Moreover as T and N categories and stage of the tumor rose, the AgNOR number also rose, but not significantly. More interestingly, the mean AgNOR number was significantly higher in the presence than in the absence of lymph node metastasis. These studies indicate that the AgNOR number might be of clinical value as a predictor of lymph node metastasis of supraglottic carcinomas.


Auris Nasus Larynx | 1997

Clinical study of esophageal foreign bodies attributable to PTP material

Atsushi Sakakura; Yuzo Yamamoto; Miho Terada; Hiroshi Takenaka; Noriko Ueda; Tomohiro Furuya

Retrospective survey of patients with esophageal foreign bodies who were treated in the Osaka Medical College over the past 21 years, and the patients with esophageal foreign bodies attributed to press through package (PTP) who were treated at the Osaka Central Emergency Clinic, a representative holiday emergency institution in Japan, was carried out. The incidence of foreign bodies attributed to PTP material tends to increase throughout the period reviewed. The patients over 60 years of age accounted for 25/28 (89%) of all PTP patients in Osaka Medical College and 27/32 (84%) in Osaka Central Emergency Clinic, strongly suggesting that PTP dysphagia is most common in elderly patients. Diagnostic methods and preventive measures against PTP foreign bodies were discussed.


European Archives of Oto-rhino-laryngology | 1995

Nucleolar organizer regions in glottic carcinomas: Comparison of DNA cytofluorometry and clinicopathological analysis

Yuzo Yamamoto; Takashi Itoh; Tetsuro Saka; Atsushi Sakakura; Hiroaki Takahashi

The significance of nucleolar organizer regions (NORs) and nuclear DNA content in 73 glottic carcinomas was assessed for proliferative activity and tumor progression. NORs stained with silver colloid were counted, and nuclear DNA content was assayed by cytofluorometry. The cytofluorometric study demonstrated that the percentage of tumors with aneuploidy tended to increase as histological differentiation decreased. Survival rates of patients with diploid and aneuploid tumors were not significantly different. AgNOR staining revealed that mean AgNOR numbers rose as histological differentiation of tumors decreased. Moreover, as T and N categories and stages showed advancing malignancy, mean AgNOR numbers tended to rise. However, there was no significant difference in survival rates between tumors with low and with high AgNOR counts. These studies indicate that while AgNOR staining is better than DNA cytofluorometry for determining histological differentiation of glottic carcinoma, neither is of prognostic value at the present time.


Operations Research Letters | 2000

Stereoscopic Display of a Three-Dimensional Image of the Larynx Using High-Speed Helical Scanning

Atsushi Sakakura; Yuzo Yamamoto; Yasuo Uesugi; Ken Nakai; Ibuki Hayashi; Kazuo Makimoto; Hiroshi Takenaka; Isamu Narabayashi

To evaluate the usefulness of stereoscopic images of larynges using helical CT in stereo mode, a retrospective review of the characteristics of stereoscopic viewing of larynges was made. The subjects were 3 patients with laryngeal cancer, 1 patient with laryngeal leiomyosarcoma and 1 patient with an advanced tongue carcinoma whose formalin-fixed larynx was extirpated. The larynges were scanned by high-speed helical CT using 1- to 2-mm slices. The reproduction of stereographic images was performed by the manipulation and rotation of three-dimensional structures around the y-axis on the computer display. The three-dimensional images of the complex structures, such as the arytenoid cartilage, aryepiglottic fold and pyriform sinus, were better observed by binocular images (stereograms) than by monocular images. Stereoscopic views of the larynx are useful in producing three-dimensional images of the unseen inner surface of the human body.


Practica oto-rhino-laryngologica | 1997

Clinical Studies on the Treatment and Prognosis of T3 Laryngeal Cancer.

Shigemasa Ikai; Atsushi Sakakura; Ken Nakai; Miho Terada; Yuzo Yamamoto; Kazuo Makimoto; Hiroaki Takahashi

We have treated 159 patients with laryngeal cancer over the past 15 years (Jan. 1, 1977 to Dec. 12, 1991). Of these 159 patients, 14 suffered from T3 glottic carcinoma and 13 from T3 supraglottic carcinoma; the histological diagnosis in every case was squamous cell carcinoma. The average age of the patients was 63.3 years and the male-female ratio was 13 to 1. The 5-year cumulative survival rate was 77.9% for T3 glottic carcinoma and 23.1% for T3 supraglottic carcinoma. Among the cases of glottic carcinoma, 6 patients underwent total laryngectomy. Five patients were treated by total laryngectomy and radiation, and 3 patients received radiation only. We were able to achieve primary site control in 10 of 14 cases. Among the cases of supraglottic carcinoma, 3 patients underwent total laryngectomy, 8 patients were treated by total laryngectomy and radiation, and 1 patient received radiation only. We were able to achieve primary site control in 5 of 8 cases who received laryngectomy and radiation, but were unable to in patients treated with laryngectomy without radiation therapy. Recurrences were found to appear more in cervical lymph nodes in both glottic and supraglottic carcinomas. In 13 cases with supraglottic carcinoma, 7 patients had recurrences sites in cervical lymph nodes. We concluded that elective neck dissection may be indicated for the treatment of T3 supraglottic laryngeal carcinoma.


Auris Nasus Larynx | 1995

Tracheo-esophageal shunt speech: report of an unusual case.

Atsushi Sakakura; Yuzo Yamamoto; Masashi Imanaka; Tetsuro Saka; Kazuo Makimoto; Hiroaki Takahashi

A rare case of laryngectomee who acquired TE shunt speech is reported. Our patient was a 64-year-old woman with laryngeal cancer (glottic type T3N0M0). She underwent laryngectomy in 1990, and a Komorn tracheo-esophageal shunt operation was performed simultaneously. A voice prosthesis (BIVONA) was inserted into the shunt, but the voice valve was not used. She acquired shunt speech soon after the operation, and there was no need to close the tracheostoma during phonation. Fiberoptic, X-ray and aerodynamic findings of the shunt and esophagus were as follows: (i) The one-way valve of the voice prosthesis was open during inspiration and closed during phonation. (ii) Swallowing of air, as seen in esophageal speech, was not observed. (iii) The neoglottis was in the upper part of the esophagus. It was concluded that the air for the vibration of the neoglottis entered the esophagus through the T-E shunt during inspiration.

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Ken Nakai

Osaka Medical College

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