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Y Motegi

Publications and source records attributed to Y Motegi.

At least 37 records · Page 2Linked to original sources
PubMed1992

[The correlation between vertebral artery asymmetry and pontine infarction--an MR angiography study].

The purpose of this study is to evaluate the correlation between variation of the vertebral artery (VA) and the incidence of pontine infarction. A total of 206 patients were examined using magnetic resonance imaging (MRI) and 3-dimension time-of-flight MR angiography (MRA) of the brain. Of these, 54 patients had pontine infarctions (23 symptomatic and 31 asymptomatic), and the majority of them were located in the pontine base. The sites of dominant lesion in the pons were right in 18 cases, left in 8 cases, and bilateral in 28 cases. The number of patients with VA asymmetry (the ratio of internal diameters 1:2 or more) were 89 (43.2%). Of these, 67 patients had small diametric VA of right side, and 22 of left side. Among the 117 patients with normal VA pattern, 19 (16.2%) had infarction, while among the 89 patients with VA asymmetry, 35 (39.3%) had infarction. The patients with small diametric VA of right side significantly had infarctions in the same side of the pons. The results of this study suggest that VA asymmetry is considered to be one of the risk factors of pontine infarction and that MRA can be useful in the examination of the cerebral artery as a valuable and non-invasive screening method.

Adolescent↗
PubMed1992

[Magnetic resonance angiography in 12 patients with Wallenberg's syndrome].

Magnetic resonance angiography (MRA) was performed in 12 patients with Wallenberg's syndrome (WS) in chronic stage to investigate the lesion of the vertebral artery (VA). The laterality of infarction in the medulla oblongata was confirmed with MRI: the right in four patients and the left in eight. In this study, time-of-flight MRA was evaluated. Coronal and OM sections in MRA were examined, because the former is useful to observe asymmetry and curve of the cervical VA, and the latter is useful to observe asymmetry and stenosis of the intracranial VA. In nine out of 12 patients, the ipsilateral VA was rather hypoplastic compared to the contralateral VA, and the flow of the hypoplastic VA stopped before and after entering the intracranial region. The contralateral VA of the hypoplastic cases showed curve in the neck in five patients and stenosis in the intracranial portion in one patient. A comparative study was conducted between vertebral angiogram (VAG) and MRA in four patients. Both VAG and MRA were useful in detecting hypoplasia and stoppage of the flow. It was considered that VA hypoplasia is frequently responsible for WS, and that MRA is useful in screening the vascular lesion as a non-invasive procedure to reveal changes of the bilateral VA.

Adult↗
PubMed1991

A prefecture-wide survey of mumps meningitis associated with measles, mumps and rubella vaccine.

A survey of untoward reactions, especially central nervous system reactions, after the administration of a newly introduced measles, mumps and rubella (MMR) vaccine in Gunma Prefecture, Japan, was initiated soon after 4 patients were hospitalized for aseptic meningitis. Thirty-five, 6 and 2 children developed meningitis, convulsive disorders and parotitis, respectively, within 2 months after MMR vaccination during the 8-month period extending from April to November, 1989. The time lag between MMR vaccination and meningitis ranged from 14 to 28 days in the 35 cases of meningitis. Mumps virus, isolated from the cerebrospinal fluid in 13 patients with aseptic meningitis, was characterized by determination of the nucleotide sequences of the P gene as mumps vaccine strain. The incidence of aseptic meningitis with positive mumps vaccine virus was estimated to be 0.11% (0.3% as a whole) during the 8 months from April to November and increased to 0.3% (0.7% as a whole) in September and October. We conclude that the incidence of aseptic meningitis after MMR vaccination seems to be higher than that reported previously.

Adolescent↗
PubMed1991

[11 cases of anaphylaxis caused by grand keyhole limpet (abalone like shellfish)].

We reported 11 cases of patients who developed moderate to severe anaphylactic reactions induced by the ingestion of grand keyhole limpet (GKL) and abalone. Specific IgE-mediated hypersensitivity to these shellfish was demonstrated by history, skin prick test, RAST and immunoblotting. The RAST inhibition technique revealed cross antigenicity between GKL, abalone and keyhole limpet hemocyanin. By immunoblotting analysis, the major antigens of GKL are shown in the MW range of about 38 Kd and 80 Kd.

Adolescent↗
PubMed1989

[Study of the penetration of extrinsic tracers into exposed cementum in vitro].

The purpose of the experiment was to study the possible penetration of extrinsic tracers with different molecular weights into exposed cementum in vitro and pathway of penetration. 75 human extracted teeth-55 periodontally diseased teeth and 20 embedded 3rd molars-were used. Each tooth was maintained in 0.005% fluorecein isothiocyanate (FITC) solution (M.W. 400), 0.05% FITC conjugated peroxidase solution (M.W. 40,000), or 0.01% FITC conjugated human IgG solution (M.W. 160,000) for 10 days. Morphological observations were made by means of fluorescence microscopy. Other extracted teeth were maintained in 0.05% microperoxidase solution (M.W. 1,900) for 5 days. Observations were then made using the TEM, and micrographs were taken and analyzed with an image analyzer. As a result, solutions of higher molecular weight showed lower penetration, and unexposed cementum showed a tendency toward greater penetration. Furthermore, the penetration of tracers on the surface of the cementum was along collagen fibers, but in the inner cementum, was into cementocyte lacunae and canaliculi.

Dental Cementum↗
PubMed1988

[Changes in tissue T1 of brain tumor following GD-DTPA administration--differences in T1 time course and tissue-blood ratio by histological types].

Effect of Gd-DTPA on tissue T1 were studied in 10 patients with intracranial tumors, including 4 meningiomas, 2 gliomas, 3 metastatic tumors and 1 brain abscess. T1 values were comparatively measured in the various portions of tumor tissue, peritumoral edema and normal brain before and after intravenous injection of 0.1 mmol Gd-DTPA per kg weight, with the time ranges between 5 and 60 minutes. In vivo T1 was determined by means of field focusing technique of a FONAR QED 80-alpha system (0.05T). T1 values of blood sample were also seriously measured and applied to estimate the enhancement pattern in the varied tumors. Meningiomas showed the maximal decrease of T1 5 minutes after Gd-DTPA administration and rapid recovery of T1 fairly paralleling to that of whole blood. On the other hand, such tumors as gliomas and metastasis revealed very slowly recovery of T1 followed by the similar T1 decrease just after administration of Gd-DTPA. In the portions of peritumoral edema and normal brain, there were no significant changes in tissue T1 by Gd-DTPA administration. In order to evaluate the clearance pattern of Gd-DTPA in tumor tissue, tissue-blood ratio (TBR) was calculated from the relaxation values at the terms of 5 and 30 minutes following Gd-DTPA administration. The ratios of relaxation rates, TBR 30/TBR 5, were ranged from 1.0 to 1.5 in cases of meningiomas, whereas they distributed in the ranges from 1.5 to 3.0 in the other types of brain tumors. This value of TBR 30/TBR 5 convincingly depends upon the differences in histological types of tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Spin-lattice relaxation times of bound water--its determination and implications for tissue discrimination.

Measurements were made of T1 of bound water (T1b) and bound water fraction (alpha) for gelatin solutions and human tissues (sera, brain tumor, cerebral white matter). Bound water fraction in each sample was measured by means of thermal analysis (differential scanning calorimetry: DSC). T1 values were measured by FONAR QED 80-alpha. T1b values were calculated by an equation derived from the fast-exchange two-state model. In the study of gelatin solutions, the relationship between T1 and water content differed depending on the sort of solutions. This was considered to be due to differences in T1b values. In each biological tissue the values of T1b and alpha had different distributions. These results indicate that values of T1b and alpha for biological tissues may be altered in correspondence to the changes in pathophysiological states in those tissues.

Blood↗
PubMed1987

[Evaluation of peritumoral edema by proton T1 values with special remarks on time courses following intracranial surgery].

Proton NMR is said to be sensitive to change in tissue water content. Much more attention has been paid to clinical NMR technique for evaluating pathophysiological states including intracranial edema dynamics. This paper describes the follow up data in NMR imaging and spin-lattice relaxation time (T1) measurement in peritumoral brain tissues. Special attention was directed to the time course of focal T1 values before and after surgery. Twenty-one patients with brain tumor, including 6 meningiomas, 7 gliomas and 8 metastatic tumors, were subjected to the present studies in the term from March 1983 to September 1985. Age distribution of this series ranged from 39 to 74 years (average: 58.2). Fonar QED 80-alpha system was applied for NMR examinations of dual modes (static magnetic field: 433 gauss), i.e. image display by steady state free precession (SSFP) and in vivo T1 measurement by field focussing technique. Standard T1 values for healthy brain were 290 +/- 41 ms and 230 +/- 34 ms (mean +/- SD) in cerebral gray and white matter, respectively. Both T1 values in tumors and in peritumoral tissues before craniotomy were obviously prolonged as compared to standard T1 of corresponding site. However, it remained difficult to discriminate statistically these histological differences by preoperative T1 values. Time course of peritumoral T1 was characteristic in accordance with the sorts of brain tumor. T1 values in the brain parenchyma around meningioma were shortened after operation in the earlier stage up to 1 month, showing relatively rapid normalization in T1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1986

[Hemodilutional therapy in raised intracranial pressure; observations in a case of cerebral infarction associated with polycythemia vera].

A 36-year-old man presented with sudden onset of hemorrhagic cerebral infarction in association with polycythemia vera. On admission this patient manifested semicomatous state and left hemiplegia which were gradually progressed. X ray CT demonstrated a severe hemorrhagic infarction in right MCA territory accompanying marked shift of midline structures. Cerebral angiograms represented occlusion of right MCA showing floating emboli in the internal carotid. Hematocrit value was found to be high as 61.2 per cent. Elevated ICP levels were noted by means of epidural pressure monitoring. Deterioration of patient status was considered to be based on impairment of cerebral circulation due to hemostasis by elevated blood viscosity. In addition to administration of mannitol solution, intermittent exsanguinations, 1000 ml in total amount, were performed and hematocrit levels were corrected by hemodilution. Consciousness level was remarkably improved in accordance with reduction of ICP, which well corresponded to values of hematocrit. Level of ICP and tissue perfusion are convinced to be strongly affected by hemorheological factor in the state of raised ICP.

Adult↗
PubMed1986

[Time course of NMR images and T1 values associated with hypertensive intracerebral hematoma].

The present study describes time courses in tissue T1 values, as well as in NMR imagings, associated with hypertensive intracerebral hematoma (ICH). Non-operative 21 cases of ICH were examined by FONAR QED 80-alpha NMR system, which possessed dual modes of image display and focal T1 measurement (static magnetic field: 433 gauss). As the first step of examination SSFP images are displayed and then, at the regions of interest, absolute values of T1 are measured by field focusing technique. The extent of ICH was revealed as high density zone in NMR imaging, occasionally represented much wider extent of high density area than the finding on X-ray CT. Prolonged T1 values were obtained from such high density zone. This wide-spread high density area was regarded to reflect the spread of perifocal brain edema. T1 value of the hematoma itself was rather shortened in its initial phase within 2 weeks, thereafter followed by prolongation in the time lapse. This seemed to reflect the alterations in the properties of hematoma such as clot formation in earlier phase and resolution in later phase. On the contrary, T1 in the brain tissue surrounded to hematoma was apparently prolonged in the early phase within 2 weeks, representing the maximal values of 312 msec around 2 to 4 weeks after the onset, and then gradually normalized in the period over 1 month. This alteration in tissue T1 likely represents the processes of edema formation and its regression in perifocal zone. T1 values measured in perifocal region might be available for the evaluation of edema state in association with cerebrovascular accident.

Adult↗
PubMed1984

Effect of pulp vitality on periodontal reattachment following free autogenous gingival graft in dogs.

The aim of the present study was to examine the effects of pulp vitality on the periodontal reattachment following the free autogenous gingival graft. Maxillary bilateral premolars in each of 4 dogs were used. Denuded root surfaces were prepared after the labial alveolar osteotomies on the experimental region. 4 weeks later, the pulp in the right teeth was exstirpated and the root canals either were filled with gutta percha points and root canal sealer or were left open (infected teeth). The left teeth were kept in the vital pulp as a control. The graft was placed over the denuded root after 4 weeks. The animals were sacrificed 4 and 12 weeks postoperatively and a serial section of the premolars with surrounding tissues was prepared for a light microscopic examination. The clinical and histopathological findings showed that the gingival recession was more found in the infected teeth than the vital teeth and the former produced less periodontal reattachment as compared with the latter, and the interface between the donor and the recipient bed was characterized by the increased number and size of blood vessels.

Animals↗