Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Keiichi Ichimura is active.

Publication


Featured researches published by Keiichi Ichimura.


Auris Nasus Larynx | 1996

Effect of New Macrolide Roxithromycin upon Nasal Polyps Associated with Chronic Sinusitis

Keiichi Ichimura; Yuh-Ichi Shimazaki; Toshio Ishibashi; Ryuzaburo Higo

We often observe shrinkage of nasal polyps with low-dose long-term macrolide treatment, which was recently developed in Japan for the treatment of intractable chronic sinusitis. In order to assess the efficacy of this treatment for nasal polyps, we administered the new macrolide roxithromycin (RXM) (1 tablet: 150 mg a day) for at least 8 weeks to 20 patients with nasal polyps associated with chronic sinusitis. It was competent in controlling nasal polyp with the overall incidence of improvement being 52%. The combination of RXM with azelastine (1 mg twice/day), an inhibitor of mediator release, was examined in 20 other patients. It augmented the rate of improvement to 68%, but the increase was not significant. The incidence of improvement increased with time after the start of medication in both groups. Smaller polyps were more likely to decrease in size, but some larger polyps also markedly decreased in size. Associated allergic conditions and the extent of eosinophilic infiltration had no relation to the treatment result. We speculate that the mechanism of effectiveness of RXM is through its suppressive potency in cytokine production from inflammatory cells.


Cancer | 1999

Low p27 expression correlates with poor prognosis for patients with oral tongue squamous cell carcinoma

Hiroyuki Mineta; Katsutoshi Miura; Ikuko Suzuki; Satoru Takebayashi; Hajime Amano; Keisuke Araki; C T Hidekazu Harada; Keiichi Ichimura; Johan Wennerberg; Michael Dictor

p27, a cyclin‐dependent kinase inhibitor, regulates progression from G1 to S phase. There have been a few clinical reports of low p27 expression associated with poor survival among patients with cancer; however, there have been no reports of such an association in cases of head and neck cancer. The authors investigated whether p27 expression in patients with oral tongue squamous cell carcinoma was associated with their prognosis.


Journal of Laryngology and Otology | 1996

Surgical management of the plunging ranula : a review of seven cases

Keiichi Ichimura; Yasushi Ohta; Niro Tayama

We have treated seven patients with a plunging ranula during the past 10 years. All patients underwent surgery via a cervical approach. In two, the ranula reached the anterior neck by passing through a dehiscence in the mylohyoid muscle, while in the other five the plunging ranula passed posteriorly to the mylohyoid muscle. A pseudocyst was extirpated in each patient. Although total sublingual gland excision was not performed in two patients, no recurrence was observed in any patient. Incision of the pseudocyst facilitated subsequent procedures and decreased the incidence of transient facial paralysis. In the presence of a cervical mass without swelling of the oral floor, a cervical approach may still be the method of choice either for the first operation or for salvage surgery after recurrence subsequent to intraoral procedures. It is based on the fact that there may be ectopic sublingual glands residing on the inferior surface of the mylohyoid muscle.


Otolaryngology-Head and Neck Surgery | 2002

Stomal recurrence after total laryngectomy for squamous cell carcinoma of the larynx.

Yutaka Imauchi; Ken Ito; Esao Takasago; Ken-ichi Nibu; Masashi Sugasawa; Keiichi Ichimura

OBJECTIVE : Stomal recurrence after total laryngectomy is one of the most serious issues in the management of laryngeal carcinoma. The management of stomal recurrence, including chemotherapy, radiotherapy, and surgery, has been reported as unsatisfactory. STUDY DESIGN AND SETTING : From 1985 to 1995, 69 patients underwent total laryngectomy for the treatment of laryngeal cancer at the University of Tokyo Hospital. To identify the risk factors for stomal recurrence, we analyzed these patients according to various clinicopathological factors. RESULTS : Stomal recurrence developed in 6 of 69 patients who underwent total laryngectomy for laryngeal carcinoma. Statistical analysis reveals that primary site, preoperative tracheotomy, and paratracheal lymph node metastasis are significant risk factors for stomal recurrence. CONCLUSION : Intensive follow-up should be performed for patients with glottic carcinoma who had preoperative tracheotomy, paratracheal lymph node metastasis, or both to detect stomal recurrence at an early stage.


Acta Neurochirurgica | 1998

Dumbbell Type Jugular Foramen Meningioma Extending Both into the Posterior Cranial Fossa and into the Parapharyngeal Space: Report of 2 Cases with Vascular Reconstruction

Nobutaka Kawahara; Tsutomu Sasaki; Ken-ichi Nibu; Masashi Sugasawa; Keiichi Ichimura; Takashi Nakatsuka; Atsushi Yamada; Takaaki Kirino

Summary Two cases with huge dumbbell type jugular foramen meningioma with extension into the parapharyngeal space are reported. A well co-ordinated surgical strategy for total resection to this high risk tumour with neurosurgeons, otolaryngologists and plastic surgeons is mandatory to minimise operative complications. Both of our patients presented with a cervical mass and lower cranial nerve palsies, and had huge dumbbell type masses extending from the posterior cranial fossa through the jugular foramen to the parapharyngeal space, encasing the cervical internal carotid artery. Gross total resection of the tumours was successfully achieved by basically a 2-stage operation. In the first stage, posterior fossa tumours were removed by the transjugular approach, combined with the petrosal approach in one case. In the second stage, cervical tumours were removed along with the cervical carotid artery by the transcervical and/or transmandibular approach, followed by vascular reconstruction from the ipsilateral carotid artery to the middle cerebral artery using saphenous vein graft. From these experiences, we recommend this 2-stage operation for large dumbbell type meningiomas extending to the infratemporal/parapharyngeal space. The intracranial tumour is removed at the first operation. The extracranial portion is resected at the second, and if necessary, the involved cervical carotid artery is resected and simultaneous revascularisation using saphenous vein graft is performed with a vascularised free muscle graft. This strategy could maximise the functional preservation on the one hand, and minimise the surgical risk, such as postoperative infection, on the other.


Auris Nasus Larynx | 1993

Can Rouvière's Lymphnodes in Non-Malignant Subjects be Identified with MRI?

Keiichi Ichimura

The lateral retropharyngeal lymph nodes lie between the carotid artery and prevertebral muscles. These are most obvious anterior to the arch of C1, but can be seen to the level of the soft palate. The uppermost-positioning nodes anterior to the atlas are called as the nodes of Rouvière. Introduction of CT and MR has provided us the chance to detect them. In order to find out the frequency of identifying them in normal subjects, I examined axial MR images which had been taken for the last 3 years. A total of 90 patients (86 adults and 4 children) with a variety of diseases except for malignancies were selected. All 4 children showed Rouvières nodes bilaterally, while only 5 of 86 adults (5.8%) depicted them. The lymph nodes were identified as isointense masses as nasopharyngeal lymphoid tissues (adenoids), when presented, with the size ranged from 4 to 13 mm. The nodes with a diameter of 5 mm or more were easily identified particularly with T2-weighted images. The benign reactive adenopathy appeared indistinguishable from that demonstrated in patients with malignant tumors in the head and neck.


Otolaryngology-Head and Neck Surgery | 1999

Cervical vertebral osteomyelitis revisited: A case of retropharyngeal abscess and progressive muscle weakness:

Masayuki Sakamoto; Keiichi Ichimura; Niro Tayama; Masaichi Nakamura; Koichi Inokuchi

Vertebral osteomyelitis is a relatively rare condition and comprises 2% to 7% of all hematogenous bone infections; furthermore, only 6.5% are located in the cervical region.1 The mortality rate ranged from 25% to 71% before the antibiotic era.2 The use of antibiotics has decreased the rate, but the incidence of pyogenic vertebral osteomyelitis in recent years appears to have increased.1 Because of its insidious and sometimes bizarre clinical presentation, there is usually a considerable delay in diagnosing pyogenic osteomyelitis. This delay is even longer when vertebral osteomyelitis is complicated by neurologic involvement. Few cases with this bizarre presentation associated with retropharyngeal abscess have been reported. In this article we describe a case initially diagnosed as a retropharyngeal abscess that proved to be cervical vertebral osteomyelitis. CASE REPORT


International Journal of Pediatric Otorhinolaryngology | 1996

Auditory brainstem responses in infants and children with anoxic brain damage due to near-suffocation or near-drowning.

Kimitaka Kaga; Keiichi Ichimura; Eiji Kitazumi; Kazuo Kodama; Fumi Tamai

We studied auditory brainstem responses (ABRs) of sixteen infants and children with brain damage after anoxic accidents due to near-suffocation or near-drowning. The patients manifested cerebral palsy, mental retardation and/or epilepsy and showed poor responses in the behavioral audiometry. Auditory brainstem responses were abnormal in five of the patients in the near-drowning group (waves I, II and III only were present in three patients and the amplitudes of waves IV and V were low in two patients) but normal in most of the patients in the near-suffocation group. This difference in the ABRs between the two groups suggest that in infants and children anoxic brain damage due to near-drowning might involve not only the cerebral cortex and subcortical white matter but also the upper brainstem and midbrain.


European Archives of Oto-rhino-laryngology | 1995

Essentials of surgical treatment for intramasseteric hemangioma

Keiichi Ichimura; Ken-ichi Nibu; Toshiyoshi Tanaka

Although rare, surgical treatment may become necessary for patients with intramasseteric hemangiomas. Possible bleeding, neural injury or postoperative dysfunction are factors limiting surgical approaches. We present the following surgical highpoints for tumors involving the masseter muscles. These include careful preoperative planning with computed tomography and magnetic resonance imaging, as well as a surgical approach that provides adequate exposure for optimal tumor resection and identification of vital anatomic structures. In particular, care must be taken to preserve branches of the facial nerve. In certain cases, preoperative embolization or ligation of vessels feeding tumor helps to minimize blood loss. Whenever possible, complete tumor should be adequately resected with a surrounding margin of normal muscle. Postoperative lymphedema can be minimized by preserving the mandibular periosteum and oral or parenteral use of medication with anti-inflammatory agents. At the University of Tokyo, continuous suction is preferred with a fenestrated drain or pressure dressing with a Penrose drain should be applied to prevent hematoma. Postoperative dysfunction, such as trismus, is prevented by supportive measures.


Operations Research Letters | 2000

Immunohistochemical localization of proliferating cells and epidermal growth factor receptors in mouse olfactory epithelium.

Yasushi Ohta; Keiichi Ichimura

We investigated age-related changes in proliferating cells and epidermal growth factor receptors (EGFRs) in mouse olfactory epithelium using an immunohistochemical method with the antiproliferating cell nuclear antigen (PCNA) antibody and the antihuman EGFRs antibody. Many PCNA-positive cells occurred in the surface and basal layers of the olfactory epithelium in the embryonal and neonatal mice. However, only some PCNA-positive cells occurred in the basal layer of adult mice, and only a few presented in the basal layer of aged mice. EGFRs were observed in all layers of the olfactory epithelium at the embryonal and neonatal stages, but were not identified in the olfactory epithelium at the adult or aged stages. We believe that a decrease in EGFRs in the olfactory epithelium induces the inhibition of cell proliferation, with the resultant atrophy of the olfactory epithelium.

Collaboration


Dive into the Keiichi Ichimura's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Masashi Sugasawa

Saitama Medical University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Kimitaka Kaga

International University of Health and Welfare

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge