Biomedical subjects

Ichiro Yamada

Publications and source records attributed to Ichiro Yamada.

6 recordsLinked to original sources

PubMed2006

Esophageal carcinoma: evaluation with high-resolution three-dimensional constructive interference in steady state MR imaging in vitro.

PURPOSE: To determine the usefulness of high-resolution three-dimensional (3D) constructive interference in steady state (CISS) MRI for evaluating mural invasion and morphologic features in esophageal carcinomas. MATERIALS AND METHODS: Twenty-four esophageal specimens with carcinomas were studied with a 1.5-T system using a 4-cm-diameter loop coil. High-resolution 3D-CISS MR images were obtained with a field of view (FOV) of 80 mm, matrix of 256 x 256, and section thickness of 0.5 mm (voxel size of 0.05 mm(3)). 3D-CISS MR images were compared with histopathologic findings, and virtual MR endoscopic images were compared with macroscopic findings at surgery. RESULTS: 3D-CISS MR images clearly depicted the normal esophageal wall as consisting of eight layers, which correlated well with the histologic layers. In 22 of 24 esophageal carcinomas (92%), the depth of mural invasion visualized with 3D-CISS MRI correlated well with the histopathologic staging. In all 24 carcinomas (100%), virtual MR endoscopic images clearly depicted the macroscopic types of the carcinomas, including adjacent lymph node swelling. CONCLUSION: High-resolution 3D-CISS MRI has a high diagnostic accuracy for evaluating mural invasion and macroscopic findings in esophageal carcinomas, and may be applicable to preoperative histopathologic staging and morphologic evaluation.

Aged↗

PubMed2005

[The influence of ageing and seasons on infantile eczema - a population-based cohort study of babies aged 4 months and 10 months].

BACKGROUND: This is probably the first report of a population study on infantile eczema performed for 12 months at two ages of 4 months and 10 months on the same infant group. METHODS: The Fujiidera Health Center services the health needs of 181,994 inhabitants of Habikino and Fujiidera cities. Between September 1990 and August 1991,1775 newborns were called for a health check-up performed twice a months when they reached 4 months of age. This was repeated for a year when the infants reached 10 months of age. A total of 1493 4-month old infants and 1264 10-month old infants were examined. An expert dermatologist joined this and performed a complete skin examination throughout the study. The eczematous skin changes were evaluated at 50 different points on the body and scored using an originally made chart. Scratch marks were also evaluated at each area. Based on the scores computed eczema was diagnosed when the total score crossed a threshold number. Based on this the examiner diagnoses were categorized as follows: Degree 1: no need to visit a doctor, Degree 2: visit to doctor required, Degree 3: treatment required. Gender was not considered. The data was analyzed by an originally made software using DEC-7000 computer. RESULTS: Of all the 4-month old infants examined 329 (22.0%) were initially diagnosed to have eczema while of all the 10-month old infants examined 268 (21.2%) were initially diagnosed to have eczema. Further, out of the 329 4-month old infants initially diagnosed with eczema, 228 were again examined when they were 10-months old. Of this sample; 123 (9.7%) infants showed continued symptoms of eczema and 165 (13.1%) infants no longer showed signs of eczema. In addition, out of the 976 4-month old infants initially diagnosed without eczema, 145 (11.5%) newly developed eczema at 10 months. Hence the cumulative diagnosis rate of eczema reached 34.3%. Meanwhile the monthly diagnosis number was significantly higher in Feb (OR 1.84, p=0.031) and significantly lower in Aug (OR 0.21, p<0.001) than the expected number calculated from monthly examination number and the annual diagnosis rate at 4 months. This observation was also the case at 10 months (Feb; OR 2.19, p=0.02, Aug; OR 0.36, p=0.015). The degree of eczema was significantly higher (p<0.001, Mann-Whitney's U test) at 4 months than 10 months. When this was seen monthly, degree 3 was most prevalent in February-March, while degree 2 was most prevalent in October-January for the 4-month olds. For the 10-month olds, both the degree 3 and degree 2 were quite low throughout the year and only degree 1 showed a monthly change similar to degree 2 plus degree 3 of the 4-month olds. CONCLUSION: We therefore conclude that eczematous skin manifestations of infantile eczema are easily changeable by age at less than 1 year and are strongly influenced by seasons.

Aging↗

PubMed2004

Chiral norbornadienes as efficient ligands for the rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to fumaric and maleic compounds.

[reaction: see text] A rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to fumaric and maleic compounds has been developed. While phosphorus-based chiral ligands fail to induce high stereoselectivity, chiral norbornadiene ligands have proved to be uniquely effective to achieve high enantioselectivity in these 1,4-addition reactions.

Boronic Acids↗

PubMed2003

Trigeminal neuralgia: evaluation of neuralgic manifestation and site of neurovascular compression with 3D CISS MR imaging and MR angiography.

PURPOSE: To evaluate three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance (MR) imaging and MR angiography with multiplanar reconstruction (MPR) for detection of neurovascular compression (NVC) in patients with trigeminal neuralgia and to evaluate the relationship between clinical symptoms related to trigeminal branches and those related to the site of trigeminal nerve compression. MATERIALS AND METHODS: Fifty-four consecutive patients with trigeminal neuralgia were examined at 3D CISS imaging and MR angiography with a 1.5-T MR system. Original transverse and four reformatted images were used for image interpretation. Vascular contact with the trigeminal nerve at the root entry zone (REZ) was determined, and the nature of the involved vessels was identified. The position of the blood vessel compressing the nerve was classified into cranial, caudal, medial, or lateral sites. Statistical analysis was performed with the chi2 test or the Fisher exact test between two groups and with the chi2 test among more than two groups. RESULTS: In 12 of 15 patients who underwent surgery, the artery that was considered a responsible vessel at 3D CISS imaging and MR angiography was confirmed as such. In the other three patients, the vein was the responsible vessel, which was detected only at 3D CISS imaging. Sixteen (89%) of 18 patients with symptoms related to the maxillary division had NVC at the medial site of the REZ, while 16 (76%) of 21 patients with symptoms related to the mandibular division had NVC at the lateral site (P <.001, chi2 test). CONCLUSION: 3D CISS MR imaging with MPR is useful in the detection of NVC in patients with trigeminal neuralgia, compared with MR angiography. A close relationship was found between the region of neuralgic manifestation and the site of trigeminal nerve compression.

Adult↗

PubMed2003

Estimation of the endolymphatic sac and vestibular aqueduct using magnetic resonance imaging.

OBJECTIVE: To evaluate the diagnostic accuracy of magnetic resonance imaging for assessment of the endolymphatic sac and vestibular aqueduct. STUDY DESIGN: Imaging and histological study of the cadaver. METHODS: Five cadavers were studied by a 1.5-T magnetic resonance imaging system with a 3-inch-diameter surface coil. Magnetic resonance imaging scans were obtained with proton density-weighted and T2-weighted fast spin-echo sequences. Histological sections were made with an epoxy resin-embedding method and were compared with magnetic resonance imaging scans. RESULTS: The visibility of the endolymphatic sac on both sequences corresponded well to the presence of the endolymphatic sac on histological sections. On the histological sections, the width of the external aperture of vestibular aqueduct (endolymphatic sac including surrounding connective tissue) was 0.96 +/- 0.18 mm (mean +/- SD) and the width of lumen of endolymphatic sac at the same point was 0.47 +/- 0.17 mm. The width of the endolymphatic sac was 1.02 +/- 0.19 mm on proton density-weighted images and was 0.81 +/- 0.15 mm on T2-weighted images. The widths of endolymphatic sac measured on proton density-weighted image and those of vestibular aqueduct on histological section did not show statistically significant differences (P >.05). On the other hand, the endolymphatic sac as measured on T2-weighted image tended to be smaller than the vestibular aqueduct (P <.05) and tended to be larger than the lumen of the endolymphatic sac (P <.0005). CONCLUSION: Both sequences can precisely depict the endolymphatic sac; however, the proton density-weighted image is a more appropriate indicator of the actual anatomical configuration of the endolymphatic sac with surrounding connective tissue and vestibular aqueduct.

Aged↗

PubMed2002

Distance from acoustic neuroma to fundus and a postoperative facial palsy.

OBJECTIVE/HYPOTHESIS: Generally, patients with small acoustic neuroma have less facial palsy after its removal. The middle cranial fossa approach is mainly applied to the small acoustic neuroma and tumor size does not influence the prognosis of facial palsy. The internal auditory canal cannot be fully opened in the middle cranial fossa approach, and the facial nerve is tightly attached in the fundus. According to these anatomical factors, we hypothesized that acoustic neuromas located away from the fundus might be removed with less facial nerve damage. We investigated the distance between the acoustic neuroma and fundus and its clinical relationship. STUDY DESIGN: Retrospective study of 45 patients with acoustic neuroma who underwent a middle cranial fossa approach. METHODS: The distance between the acoustic neuroma and fundus and the tumor diameter were measured on T2-weighted and contrast-enhanced magnetic resonance images, respectively. These data were compared with the postoperative facial nerve function. RESULTS: The mean distance was 3.0 +/- 1.8 mm (range, 0-10 mm), and the mean diameter was 11.3 +/- 3.7 mm (means +/- standard deviation; range, 4-20 mm). Neither the distance nor the diameter had any correlation to the degrees of postoperative facial palsy either immediately or at 3 months after surgery. CONCLUSIONS: As far as the nerve was anatomically preserved, postoperative facial nerve function seemed to be influenced by factors other than surgical manipulation among small acoustic neuromas. Although the tumor fills in the fundus, it may not influence postoperative facial nerve function and also may not interfere with indication of the middle cranial fossa approach for removal of the acoustic neuroma.

Adult↗