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Biomedical subjects

M Yasumoto

Publications and source records attributed to M Yasumoto.

At least 19 recordsLinked to original sources
PubMed2002

Development of a multilayer Fresnel zone plate for high-energy synchrotron radiation X-rays by DC sputtering deposition.

Hard X-ray microscopy with high spatial resolution ( or=20 keV) because a large thickness (aspect ratio) can be available. Various types of multilayer FZPs have been fabricated by DC sputtering deposition. Their focusing characteristics have been evaluated at the high-brilliance undulator beamline BL47XU of SPring-8. An optical system using a Cu/Al multilayer FZP (with an outermost zone width of 0.25 microm) as the focusing optics fabricated by the optimum deposition condition with precise film (zone) thickness control has attained an almost diffraction-limited microbeam of 0.3-0.35 microm at 8.9 keV. A line-and-space resolution test pattern has been observed: fine structures up to 0.2 microm were clearly observed in the measured image. This FZP has been working since 1995, keeping good focusing characteristics. It can be said from these results that a spatial resolution better than 0.1 microm in the high-energy X-ray region is in prospect by the development of a multilayer FZP with a narrower outermost zone width in the near future.

Journal Article↗
PubMed2002

Hard X-ray microbeam experiments with a sputtered-sliced Fresnel zone plate and its applications.

Hard X-ray microbeam experiments with sputtered-sliced Fresnel zone plates have been performed. Zone plates with an outermost zone width of 0.25 microm (#FZP1) and 0.1 microm (#FZP2) were fabricated and evaluated. In a scanning X-ray microscopy experiment, a line-and-space pattern with structure as fine as 0.1 microm was resolved using #FZP2 at an X-ray wavelength of 1 A. As an application of the microbeam technique, a two-dimensional distribution of constituent elements in forensic samples has been obtained (e.g. section view of human and elephant hairs) using fluorescent scanning microscopy.

Animals↗
PubMed2002

Zernike-type X-ray imaging microscopy at 25 keV with Fresnel zone plate optics.

A Zernike-type imaging microscope using a sputtered-sliced Fresnel zone plate (SS-FZP) has been developed and tested at an X-ray energy of 25 keV. The SS-FZP was used as an objective. A copper (Cu) phase plate was placed at the back focal plane of the SS-FZP in order to produce phase contrast. The performance of the Zernike-type imaging microscope was tested with a gold (Au) mesh and a resolution test pattern at undulator beamline 47 of SPring-8. The Au mesh and the resolution test pattern could be imaged in transmission with a magnification of x10.2. Owing to the Cu phase plate, different image contrast was observed compared with the bright-field image contrast. Tantalum microstructures down to 0.5 microm line-and-space have been observed on spatial resolution test patterns.

Journal Article↗
PubMed2002

MR detection of iliac bone marrow involvement by malignant lymphoma with various MR sequences including diffusion-weighted echo-planar imaging.

OBJECTIVE: To assess the diagnostic accuracy of MR imaging for detecting bone marrow infiltration by malignant lymphoma. PATIENTS AND DESIGN: Fifty-three patients with malignant lymphoma underwent MR imaging and bone marrow biopsy. In 80 iliac crests of the 53 patients (13 positive specimens in 9 patients and 67 negative specimens in 44 patients), biopsy results and the signal intensity characteristics were compared. MR sequences included T1-weighted SE, T2-weighted FSE with fat suppression, FSE STIR, and diffusion-weighted EPI with fat suppression at 1.5 T. RESULTS AND CONCLUSIONS: To detect lymphoma infiltration, T1-weighted SE had the highest sensitivity (92%) and diffusion-weighted EPI with fat suppression and FSE STIR had the highest specificity (92.5% and 92%, respectively). A combination of T1-weighted SE and FSE STIR yielded the highest sensitivity and specificity (85% and 97%, respectively). A combination of T1-weighted SE and FSE STIR sequences seems to be the current choice of imaging protocol for detecting bone marrow infiltration by malignant lymphoma.

Biopsy↗
PubMed2001

Relationship between bone marrow cellularity and apparent diffusion coefficient.

This study was performed to determine if there is a relationship between apparent diffusion coefficient (ADC) and cellularity of bone marrow of the posterior ilium. Four groups of various marrow cellularity underwent diffusion-weighted echo-planar imaging: 1) adults with normal hypocellularity (21 patients); 2) adults with normal normocellularity (13 patients); 3) young children with normal hypercellularity (5 patients); and 4) adults with lymphoma-related hypercellularity (3 patients). In all adults, marrow cellularity was confirmed by uni-or bilateral bone marrow biopsies. In children, the iliac marrow was presumed hypercellular because of their ages. A total of 66 ADC values of bone marrow calculated from diffusion-weighted images with b-values of 30 and 300 seconds/mm(2) was evaluated. Hypercellular marrow (normal and lymphoma-related) showed the highest mean ADC, and hypocellular the lowest ADC. Statistically significant differences were found between three groups of normal marrow: hypocellular, normocellular, and hypercellular. There is a positive correlation between ADC and cellularity of bone marrow. J. Magn. Reson. Imaging 2001;13:757-760.

Adult↗
PubMed2000

MRI of ranulas.

We reviewed the MRI of 20 patients with a ranula (8 simple and 12 plunging) and ten with other cystic masses in the floor of the mouth and/or suprahyoid portion of the neck (three haemangiomas, two neuromas, one monomorphic adenoma, one lipoma, two lateral cervical cysts and one dermoid cyst). Histological diagnoses were obtained in all cases with the exception of one presumed haemangioma. Ranulas were all well-defined, homogeneous masses giving low signal on T1- and markedly high signal on T2-weighted images. While simple ranulas were all confined to the sublingual space, plunging ranulas were centered on the submandibular space and tended to spill into one or more adjacent spaces. They extended into the sublingual space anteriorly (producing a so-called tail sign) in eight of 12 cases and into the parapharyngeal space superiorly in five. Although they sometimes filled a considerable part of the parapharyngeal space, displacement of surrounding muscles or vessels was usually slight, which was thought to reflect the nature of extravasation pseudocysts. All other cystic masses in our study had one or more MRI finding different from those of ranulas and could be easily differentiated from them.

Adolescent↗
PubMed2000

Primary malignant lymphoma of the maxillary sinus: CT and MRI.

We reviewed the CT and MRI of seven patients with primary malignant lymphoma of the maxillary sinus to find if there are characteristic imaging findings suggestive of the disease. The images were analysed for appearance, size, signal, internal characteristics, extent of tumour, bone change and lymph node enlargement. In two patients, the tumour first presented with mucosal thickening. In the remaining five, the tumours were an expansile mass 4-6 cm in diameter at the time of detection. Although it was difficult to distinguish tumour from mucosa or obstructed fluid on CT, T2-weighted MRI enabled us to separate tumour from normal mucosa or fluid. In two patients, the tumours were heterogeneous. Calcification and haemorrhage were observed in one patient. Periantral soft-tissue infiltration was always present, even when tumour appeared as slight mucosal thickening. Posterior extension was seen in all patients. Permeative and lytic bone destruction accompanied most cases of periantral soft-tissue infiltration; mixed destruction and sclerosis was also observed. Mucosal thickening with periantral soft-tissue infiltration may suggest malignant lymphoma of the maxillary sinus in its early form. Various types of bone change may accompany the periantral soft-tissue infiltration.

Adult↗
PubMed2000

New terpenoid components from the volatile oils of the soft corals Clavularia viridis and Sarcophyton acutangulum.

A new tetracyclic terpenoid hydrocarbon, cyclosinularane (1), and (+)-alloaromadendrene (2), the enantiomer of terrestrial (-)-alloaromadendrene, have been isolated from the volatile oil of the soft corals Clavularia viridis and Sarcophyton acutangulum, respectively. Their structures have been determined on the basis of NMR spectral analysis and their chiroptical properties.

Animals↗
PubMed1999

Identification of HLA-A24 epitope peptides of carcinoembryonic antigen which induce tumor-reactive cytotoxic T lymphocyte.

Carcinoembryonic antigen (CEA), which is expressed in several cancer types, is a potential target for specific immunotherapy. HLA-A24 is the most frequent allele among Japanese and is also frequently present in Asians and Caucasians. We tested CEA-encoded HLA-A24 binding peptides for their capacity to elicit anti-tumor cytotoxic T lymphocytes (CTL) in vitro. For this purpose, we used CD8+ T lymphocytes from peripheral blood mononuclear cells (PBMC) of a healthy donor and autologous peptide-pulsed dendritic cells as antigen-presenting cells. This approach enabled us to identify 2 peptides, QYSWFVNGTF and TYACFVSNL, which were capable of eliciting CTL lines that lysed tumor cells expressing HLA-A24 and CEA. The cytotoxicity to tumor cells by the CTL lines was antigen-specific since it was inhibited by peptide-pulsed cold target cells as well as by anti-class I major histocompatibility complex (MHC) and anti-CD3 monoclonal antibodies (MAbs). The antigen specificity of the 2 CTL lines was examined using several tumor cell lines of various origins and for their peptide-dose responses. The identification of these novel CEA epitopes for CTL offers the opportunity to design and develop epitope-based immunotherapeutic approaches for treating HLA-A24+ patients with tumors that express CEA.

Amino Acid Sequence↗
PubMed1999

Recurrent pleomorphic adenoma of the head and neck.

We reviewed the clinical and imaging files of 15 patients with pathologically confirmed recurrent pleomorphic adenomas of the head and neck. The primary tumours were in the lacrimal gland (1 case), cheek (2), palate (5), parotid gland (4), and submandibular gland (3). Recurrence was generally late, with an average of 14.9 years between initial surgery and recurrence. Multiple recurrent tumours, measuring 5-50 mm were found in eight patients. In all palatal cases recurrence was large and solitary. Most recurrent pleomorphic adenomas were well delineated with smooth margins, like most primary tumours. Irregularity of the margins was seen in four patients. In four of the five tumours of the palate and in the orbital lesion, the recurrent tumours caused bone destruction, thus mimicking malignant lesions. Irregular-margined recurrences seem to be rather small and found among multiple recurrent nodules.

Adenoma, Pleomorphic↗
PubMed1998

Synthesis and antiallergic activity of dimethyl-2-(phenylcarbamoyl)ethylsulfonium p-toluenesulfonate derivatives.

The derivatives of dimethyl-2-(phenylcarbamoyl)ethylsulfonium p-toluenesulfonates were synthesized and evaluated for antiallergic activity. The 2,3-dihydroxyethoxy group was introduced to the phenyl ring from the standpoint of lipophilicity and electronic effects of substituent. The IgE-induced rat passive cutaneous anaphylaxis (PCA) was inhibited by oral administration of several substituted 2-[(4-propoxyphenyl)carbamoyl]ethyldimethylsulfonium p-toluenesulfonate derivatives. Among them (+/-)-2-[N-[4-(3-ethoxy-2-hydroxypropoxy)phenyl]carbamoyl]ethyldimeth ylsulfonium p-toluenesulfonate (1a, IPD-1151T) was found to possess considerable activity in the PCA test, and it was launched as Suplatast tosilate in Japan.

Animals↗
PubMed1998

Malignant lymphoma of the gingiva: MR evaluation.

PURPOSE: Our purpose was to document the MR imaging findings of malignant lymphoma of the gingiva. METHODS: Five patients with histologically proved malignant lymphoma of the gingiva were studied by MR imaging. The MR images were analyzed for tumor size, extent, and signal characteristics, bone involvement, and associated cervical lymph node enlargement. RESULTS: Clinical examination tended to underestimate the size of lymphomatous lesions. The signal intensity of the lesions was isointense to hyperintense relative to muscle on noncontrast T1-weighted images and showed variable contrast enhancement patterns. On T2-weighted images, signal intensity was isointense to hypointense relative to the oral mucosa. In one case, the mass extended to the submandibular space; in the remaining cases, the masses were limited to the gingiva and the adjacent bone. MR imaging revealed that gingival lymphomatous masses were broad-based along the mandible or maxilla and eroded through the cortex into the marrow space, but the cortex was still recognizable. No nodal involvement was noted in any of the patients with malignant lymphoma. CONCLUSION: The signal characteristics of gingival lymphoma overlap those of other tumors. The cortex separating marrow involvement from the broad-based gingival mass generally appears to be permeated with small erosions but is still recognizable.

Aged↗
PubMed1997

Rupture of the left main-stem bronchus by the tracheal portion of a double-lumen endobronchial tube.

We report a rupture of the left main-stem bronchus following the insertion of a left-sided double-lumen endobronchial tube in a 76-yr-old woman with a short trachea. A fiberoptic bronchoscope was not used during the initial insertion of the tube and the depth of insertion resulted in approximately 5 cm in excess of the optimal level for this patient. The rupture had been caused by the tracheal portion of the double-lumen tube. This damage may have been avoided if a fiberoptic bronchoscope was used routinely as an introducer and for positioning of the endobronchial tube under direct vision.

Adenocarcinoma↗
PubMed1996

[Anesthetic management of a patient with tuberous sclerosis].

Tuberous sclerosis is characterized by facial angiofibromatosis, epilepsy, and mental retardation. There have been only a few reports of anesthetic management of patients with tuberous sclerosis. We managed a 22-year-old patient with tuberous sclerosis using nitrous oxide (67%) in oxygen supplemented with fentanyl and midazolam. There were no untoward events related to anesthesia and surgery. Problems in managing patients with tuberous sclerosis are also discussed.

Adult↗
PubMed1995

The relation between an esophageal cancer and associated cancers in adjacent organs.

BACKGROUND: The relation between esophageal cancers and head and neck tumors was studied in order to improve the treatment results in patients with multiple cancers. METHODS: We reviewed the records of 3,375 patients with an indexed squamous cell carcinoma of the head and neck treated at our institution between 1960 and 1994; and 81 patients were found to have an associated esophageal carcinoma. Similarly, the records of 434 patients with an indexed esophageal cancer were reviewed; and 54 patients had cancers in other organs or in the residual esophagus. A total of 135 esophageal cancers with 154 synchronous or metachronous cancers were entered into the analysis. RESULTS: The risk of developing esophageal cancer was ten times higher in male patients with head and neck cancer than in female patients. Synchronous or metachronous esophageal cancer associated with head and neck cancer was most frequently seen with pharyngeal cancer (28/360 = 7.8%), followed by in the oral cavity (47/2148 = 2.2%). CONCLUSIONS: Better knowledge of the relation between an esophageal cancer and a head and neck cancer may lead to the early detection of subsequent small, potentially curable neoplasms sited in either the esophagus or the head and neck region.

Carcinoma, Squamous Cell↗
PubMed1995

External and interstitial radiotherapy in the treatment of oropharyngeal squamous cell carcinoma.

The records of 165 patients with squamous cell carcinoma of the oropharynx treated at our hospital with external and/or interstitial radiotherapy between 1971 and 1990 were reviewed to evaluate the treatment results, focusing on primary control and complications. All cancers were restaged according to the UICC 1987 TNM staging system. Of these 165 patients, 11% were in Stage I, 55% in Stage II, 24% in Stage III and 8.5% in Stage IV. Local control and complications were analysed in 140 patients. The remaining 25 patients died of intercurrent or metastatic disease during the first 2 years following treatment and were excluded from the analysis. 70 patients were treated by interstitial implant using permanent implant seeds (Rn-222 in eight patients, Au-198 in 62 patients) with or without external radiation. 56 other patients received external irradiation alone and another 14 patients received pre-operative external irradiation plus surgery. 2-year recurrence-free rates were 73% (100% for T1, 76% for T2, 36% for T3 tumours) in the patients who received interstitial implant with or without external radiation and 36% (67% for T1, 48% for T2, 13% for T3 tumours) in the patients treated by external irradiation alone. The incidence of soft-tissue or bone complications requiring long-term treatment was 14%. Based on these findings, it is believed that an interstitial implant using Au-198 grains combined with external beam irradiation is a useful treatment modality for small lesions of the oropharynx.

Adult↗