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Biomedical subjects

Y Masuda

Publications and source records attributed to Y Masuda.

At least 703 records · Page 39Linked to original sources
PubMed1988

[Deformity of the cardiac structures in patients with mitral valve prolapse: the relationship with flat chest].

In view of the close relationship of mitral valve prolapse (MVP) and chest deformity, seven patients of MVP associated with flat chest were echocardiographically evaluated, and the results were compared with those of 43 normal control subjects, 29 cases with flat chest, and patients with MVP either of the anterior (25 cases) or posterior (21 cases) leaflet. MVP associated with flat chest was observed in the anterior leaflet in all cases. MVP was related to the dislocation of the two mitral leaflets caused by the displaced posterior mitral ring observed by two-dimensional echocardiography. The transition type was observed among the cases with or without dislocation of the mitral ring in cases with flat chest.

Adolescent↗
PubMed1988

[Characteristics of gastric cancer detected by mass survey. Comparison with those of outpatients].

The characteristics of gastric cancers detected by mass survey were studied by comparison with those of outpatients attending our hospital. Form 1966 to 1985, a total of 290,987 examinees were screened by gastric mass survey at our Mass Survey Center. Among them, 474 cases (0.16%) of gastric cancer were detected, and of these, 254 cases (52%) were early gastric cancer. Upon comparison of macroscopic types of surgically treated cancers, there were 152 cases (39.6%) out of 784 cases in the mass survey group and 658 cases (21.3%) out of 3,091 cases in the outpatient group having the depressed type and 11% in the former and 5.5% in the latter having the elevated type of early gastric cancer. As for the prognosis of cancers in both groups, the 5- and 10-year survival rates of 274 cases in the mass survey group and 1,859 cases in the outpatient group undergoing resection between 1964 and 1974 were compared. It was found that 80.0% for 5 years and 78.5% for 10 years in relative survival rates were obtained in the mass survey group, and 56.2% for 5 years and 55.1% for 10 years in the outpatient group. This difference in survival rate was due to the fact that the mass survey group had a high ratio of early gastric cancer than the outpatient group, and that even the advanced serosal cancer former group had less lymph node metastasis than the latter group.

Ambulatory Care↗
PubMed1988

[Two autopsy cases of primary pituitary carcinoma].

We studied two autopsy cases of primary pituitary carcinoma. Case-1. A 45 year old female was admitted on Oct. 4 1978, with a complaint of right homonymous hemianopsia. And diagnosis was pituitary adenoma. Partial removal of pituitary tumor was performed on Oct. 23 1978. She died on Dec. 5 1978 due to bleeding of gastrointestinal tract. Autopsy disclosed a pituitary carcinoma invading the left hypothalamus, mamillary body, optic and V cranial nerves, and mid brain as well as sphenoid bone. No extracranial metastasis was noted. Case-2. A 44 year old female with a history of acromegaly for 6 years was admitted with a complaint of headache on May 8 1976. She was diagnosed as having pituitary adenoma. The subtotal removal of pituitary tumor was performed on May 21 1976 and followed by 4500 rad irradiation. At this time, pathological diagnosis was eosinophilic adenoma. Seven years later, she complained of progressive right hearing disturbance, dysarthria and ataxic gait 1983. The second subtotal removal of pituitary tumor was performed with a diagnosis of recurrence of pituitary adenoma on Oct. 7 1983. After the operation, she complicated sepsis and died on Jan. 14 1984. An autopsy disclosed a pituitary carcinoma from residual pituitary gland, continuously extending to the subarachnoid space of the pons, and invading right cerebello-pontine angle and cerebellum. The histological examination revealed pituitary carcinoma with high pleomorphism and glioblastoma multiform-like feature were within the tumor.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1987

Intranuclear rod-shaped actin filament bundles in poorly differentiated axillary adenosquamous cell carcinoma.

An axillary cystic poorly differentiated adenosquamous cell carcinoma was studied by electron microscopy and immunohistochemistry for keratin, vimentin, desmin, and actin. Many tumor cells had rod-shaped intranuclear fibrillary inclusions which consisted of 60 A microfilaments. These intranuclear inclusions reacted with antiactin antibody and were considered to be F-actin bundles. The cells having intranuclear inclusions were frequently found in areas close to the cystic space, and inclusions of tumor cells close to the cyst were thicker. However, mitotic figures were predominantly found in the periphery of the tumor. Intranuclear actin is known to be mainly soluble G-actin, and one of its important functions is reported to be the chromosome condensation in mitosis. It is speculated that the cells having intranuclear fibrillary inclusions of actin have impairment of mitosis.

Actins↗
PubMed1987

Increasing anticonvulsant effect of AD-810 (zonisamide) in aging BDF1 mice.

The anticonvulsant efficacy of a newly developed anticonvulsant, AD-810 (zonisamide, 3-sulfamoylmethyl-1,2-benzisoxazole) was examined in relation to mouse age in three different age groups of female BDF1 mice (7-, 25- and 29-month-old). The minimal effective concentration (MEC) of AD-810 in both plasma and brain for abolishing the electroshock-induced maximal seizure steadily decreased with age, the 25- and 29-month values being 50 and 30% of respective 7-month values. The observation in the present study was almost identical to previous observations by the authors on phenytoin, phenobarbital and oxazepam. The present results support our previous contention that the dose and plasma concentration of anticonvulsants can (and probably should) be reduced in the elderly regardless of the drug. Since the anticonvulsant mechanism of AD-810 has been reported to differ from those of previously examined drugs (phenobarbital and oxazepam), the results also suggest that the apparent increase in the pharmacological effect of these anticonvulsants may be due to old animals' lowered response capability for seizures rather than a specific age effect on the pharmacological reaction sites for individual anticonvulsants.

Aging↗
PubMed1987

Noninvasive quantification of regional myocardial blood flow and ammonia extraction fraction using nitrogen-13 ammonia and positron emission tomography.

This report describes the theoretical basis and a method to quantitate regional myocardial blood flow (RMBF) and ammonia extraction fraction (E) in man, noninvasively, with N-13 ammonia and positron emission tomography (PET). Two patients with hypertrophic cardiomyopathy, whose left ventricular (LV) walls were markedly thick, were employed in this study to avoid partial volume effects and cross contamination between LV walls and blood pool. RMBF and E were calculated from time-activity curves of myocardial tissue and left atrium derived from serial 6-second PET images of the heart. The time-activity curve of left atrium was used as an arterial input function. The results were RMBF = 67 +/- 4 ml/min/100 g, E = 80 +/- 13% and 65 +/- 10 ml/min/100 g, 81 +/- 16% for each patient. The validity of the present method was discussed.

Ammonia↗
PubMed1987

Repeated low dose apomorphine induced subsensitivity of presynaptic dopamine receptors.

The influence of repeated administration of a low dose of apomorphine on presynaptic dopamine (DA) receptors was examined. (1) Male ddY mice were given a low dose of apomorphine (0.2 mg/kg) for 7 days. Following 2 drug-free days they were given apomorphine (0.2 mg/kg, IP), after which cage climbing behavior and the level of 3-methoxytyramine (3MT) in striatum was measured. Mice became tolerant to apomorphine's activity-depressing effect and 3MT-decreasing effect. (2) Mice were given haloperidol (1 mg/kg) for 7 days. Then after 2 drug-free days they were given 0.2 or 1.0 mg/kg of apomorphine, after which cage climbing behavior was measured. One mg/kg of apomorphine significantly increased cage climbing behavior, indicating that supersensitivity of postsynaptic DA receptors was induced by haloperidol, but the activity-depressing effect of 0.2 mg/kg of apomorphine was not modified. The results suggest that subsensitivity of presynaptic DA receptors participates in the tolerance to the activity-depressing effect of a low dose of apomorphine.

Animals↗
PubMed1987

Effects of methamphetamine and morphine on the vertical and horizontal motor activities in mice.

The effects of methamphetamine and morphine on the vertical (VMA) and the horizontal motor activities (HMA) in male ddY mice (six weeks of age) was investigated between 9:00 and 13:00, using an apparatus which can differentiate spontaneous motor activity into VMA and HMA, measuring their activities simultaneously. VMA and HMA were evaluated by counting the number of times that an infrared ray was blocked by the mouse in the activity cage. Nine infrared photo-couplers were used to measure the VMA and one to measure the HMA. All measurements were taken at 10 min intervals during the 180 min period after subcutaneous injection of methamphetamine (0.1, 1 and 10 mg/kg) or morphine (2, 10 and 50 mg/kg). A small dose of methamphetamine (0.1 mg/kg) did not exert influence on the counts of the VMA and the HMA, whereas a large dose enhanced both activities, especially at 10 mg/kg, where each activity showed qualitatively different biphasic patterns. On the other hand, three doses of morphine significantly inhibited the VMA for 20 min after administration, while morphine at 2 mg/kg depressed the HMA for 10 min after administration and at 10 mg/kg or more markedly enhanced it during the 180 min observation period. These results show that different doses of methamphetamine and morphine exert different effects on the VMA and the HMA in mice.

Animals↗
PubMed1987

Selective enlargement of the third ventricle found in chronic schizophrenia.

Selective enlargement of the third ventricle was observed when the area and the VBR (ventricle-brain ratio) were measured in 37 chronic schizophrenics (DSM-III criteria) as compared with 37 controls. However, the width or the width to IS (maximum inner skull width) ratio was not significantly different between the two groups. There was no correlation between any measure of the third ventricle and any of the clinical variables. Five patients had VBRs of the third ventricle that were larger than the mean + 2 SD of the control, but there was no significant difference between these five schizophrenics and the others in any of the clinical variables.

Adult↗
PubMed1987

Secretion of DNA synthesis factor (DSF) by A431 cells that can grow in protein-free medium.

A431 cells grew in protein-free Coon's modified Ham's F12 medium at a similar rate to that in medium supplemented with calf serum and secreted a growth factor capable of stimulating DNA synthesis in BALB/c3T3 cells. This factor had strong affinity for heparin and was partially purified from the conditioned medium by heparin-Sepharose affinity chromatography and molecular sieving on Bio-Gel P-60. The apparent molecular weight of the factor was 20-30K. Its activity was inhibited by heparin at concentrations of above 0.03 microgram/ml.

Carcinoma, Squamous Cell↗
PubMed1987

Histogenesis of unique elastinophilic fibers of elastofibroma: ultrastructural and immunohistochemical studies.

Electron microscopy and both light and electron microscopic immunohistochemical tests for elastin were employed to study the morphogenesis of the unique elastinophilic fibers of an elastofibroma removed from the subscapular region of a 62-year-old woman. Ultrastructurally, as shown by tannic acid stain, elastinophilic fibers of the elastofibroma consisted of central cores and outer zones. The latter were composed of various sizes of vaguely demarcated, irregularly shaped amorphous components and compactly and randomly arranged large amounts of microfibrils. The electron microscopic immunohistochemical results showed that the small-sized amorphous components and microfibrils in the outer zones of the elastinophilic fibers were stained evenly and of granular texture, but the vaguely outlined large amorphous components were not stained. These findings were interpreted as indicating that the amorphous components of the outer zones of elastinophilic fibers were less compact and allowed the penetration of antielastin antibody. The unique elastinophilic fibers of elastofibromas appear not to be formed by the degeneration of the fibers but by abnormal elastogenesis, including an abnormal arrangement of microfibrils.

Bone Neoplasms↗
PubMed1987

Bilaminar structure of the developing stapedial footplate in the mouse--a histological study using a light microscope.

Normal development of the stapes, especially the bilaminar structure of the footplate, in the mouse was investigated histologically. On day 14 of pregnancy, the footplate had an easily distinguishable lamina consisting of two layers. This bilaminar structure was seen clearly as a pale and loose portion composed of mesenchymal cells in the vestibular side adjacent to the original footplate in the stapedial ring. The authors considered this structure to be the same structure as the lamina stapedialis in the developing human stapes. A dualistic theory of the developmental origin of the footplate in the mouse is proposed.

Animals↗
PubMed1987

Rate of acetylcholine hydrolysis affects the phase dependency of cardiac responses to vagal stimulation.

The influence of the rate of acetylcholine hydrolysis on the magnitude and phase dependency of the cardiac chronotropic response to vagal stimulation was studied in anaesthetised dogs. In one group of animals the chronotropic response to tonic vagal stimulation varied directly with the dose of physostigmine. In a second group of animals one brief stimulus burst was delivered to the right vagus nerve during each cardiac cycle, and the timing (phase) of the stimulus was varied within the cycle. Before physostigmine was given the phase of the stimulus had a substantial influence on the chronotropic response. When each stimulus burst contained 6 pulses the response was changed from its minimum to its maximum value (mean (SEM) change 0.338(0.081) s) when the phase was shifted by a mean value of 0.091(0.031) s. After physostigmine (0.3 mg X kg-1) was given the change in response produced by a phase shift was much less pronounced. A mean shift in phase of 0.593(0.052) s was required to change the chronotropic response from its minimum to its maximum value, and the mean difference between the minimum and maximum response was only 0.140(0.032) s. Hence the rate of acetylcholine hydrolysis in the cardiac tissues is an important determinant of the phase dependency of the chronotropic response to repetitive vagal stimulation-that is, the slower the rate of hydrolysis the less the change in the chronotropic response elicited by a given change in stimulus timing.

Acetylcholine↗
PubMed1987

Action of carbon tetrachloride in the reconstituted monooxygenase system using partially purified cytochrome P-450 and P-448.

In the cytochrome P-450-reconstituted system, CCl4 stimulated NADPH-dependent lipid peroxidation of the system containing the P-450 form to a much greater extent than that of the system containing the P-448 form. When the P-450-reconstituted system was preincubated in the presence of both NADPH and CCl4, 7-ethoxycoumarin O-deethylase, aminopyrine N-demethylase and aniline hydroxylase activities were decreased by 40-60%, whereas, with P-448 form reconstituted system, no suppression was observed in these enzyme activities or in 7-ethoxyresorufin O-deethylase activity. These observations suggest that the P-450 form, but not the P-448 form, is active in metabolizing CCl4 to a reactive species that subsequently impairs the hemoprotein.

Animals↗