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Biomedical subjects

Y Masuda

Publications and source records attributed to Y Masuda.

At least 811 records · Page 45Linked to original sources
PubMed1984

Tumor-forming acute myeloid leukemia with facial paralysis.

A 55-year-old male with acute myeloid leukemia, which had been well controlled for 2 years, developed a sudden onset of facial palsy. Otologic examinations proved the right mastoid bone to be infiltrated by leukemic cells, which formed a nonchloroma to occlude the right external auditory canal. The precise site for the right facial paralysis by tumor formation was found in the intrastapedial region of peripheral portion of the right facial nerve. Regarding the tumor formation in myeloid leukemia, its frequency (particularly among Japanese subjects), complications (particularly in otologic field), possible pathogeneses, and treatments were discussed.

Audiometry↗
PubMed1984

Polychlorinated biphenyls and dibenzofurans in patients with yusho and their toxicological significance: a review.

The rice oil ingested by the patients with yusho and their blood, liver, and adipose tissue were analyzed for individual congeners of polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs). The individual congeners identified were examined for accumulation in the liver of monkeys and rats, inducing activities of benzo[a]pyrene 3-hydroxylase, benzphetamine demethylase, and DT-diaphorase in rats, and gravimetric changes of the thymus and liver in rats. Among the six PCB congeners detected in yusho patients, 2,3,4,5,3',4'-hexa-CB seems to be the compound most related to yusho judging from its strong enzyme-inducing activities in the liver and the thymus atrophy and liver hypertrophy caused by feeding it to rats. PCDF congeners identified in the patients' tissues showed a stronger toxicity in rats than these PCBs, exhibiting stronger enzyme induction activities and gravimetric changes of the tissues. These PCDF congeners, especially 2,3,4,7,8-penta-CDF, were also very accumulative in the liver. Therefore, they are considered as the most important etiologic agents for the current symptoms and signs of yusho patients.

Adipose Tissue↗
PubMed1984

Polychlorinated biphenyls and dibenzofurans in patients with yusho and their toxicological significance: a review.

The rice oil ingested by the patients with yusho and their blood, liver, and adipose tissue were analyzed for individual congeners of polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans ( PCDFs ). The individual congeners identified were examined for accumulation in the liver of monkeys and rats, inducing activities of benzo[a]pyrene 3-hydroxylase, benzphetamine demethylase, and DT-diaphorase in rats, and gravimetric changes of the thymus and liver in rats. Among the six PCB congeners detected in yusho patients, 2,3,4,5,3',4'-hexa-CB seems to be the compound most related to yusho judging from its strong enzyme-inducing activities in the liver and the thymus atrophy and liver hypertrophy caused by feeding it to rats. PCDF congeners identified in the patients' tissues showed a stronger toxicity in rats than these PCBs, exhibiting stronger enzyme induction activities and gravimetric changes of the tissues. These PCDF congeners, especially 2,3,4,7,8-penta-CDF, were also very accumulative in the liver. Therefore, they are considered as the most important etiologic agents for the current symptoms and signs of yusho patients.

Adipose Tissue↗
PubMed1984

[Ventricular interdependence reflected in interventricular septal motion: with special reference to right ventricular pressure overload].

The dynamic features of the interventricular septum were studied with two-dimensional echocardiography with special reference to the influence of right ventricular (RV) pressure overload. The subjects were 52 patients, including 30 with atrial septal defect (ASD), 14 with rheumatic mitral valvular disease and 8 with pulmonary hypertension (PH) due to cor pulmonale, pulmonary embolism, or primary PH. To assess septal motion, the configuration of the left ventricle (LV) in the short-axis view was quantified as the deformity index, and characterized as the distortion from right circle. As an accurate short axis was required to assess the deformity of the cavity, the transducer was attached to the guide arm, providing comparable positions and directions. The deformity index was highest at the chordal level among other levels in the same cardiac phase. In ASD without PH, the deformity was minimal in end systole and maximal in early diastole. The index curve showed two peaks in early diastole and these times coincided with those of the minute backward notches on the ventricular septal echogram. In ASD with PH, the deformity was minimal in early systole and became greater during systole. The maximum deformity was shown in early diastole, corresponding to the momentary retracting motion of the septum by M-mode echocardiography. At that moment, the septum became convex to the LV. In patients with RV pressure overload, the systolic peak of the RV pressure was delayed and the decrease in pressure became sluggish, resulting in the RV pressure exceeding that of the LV transiently in early diastole. This was the reason for the septum becoming convex to the LV in this phase. Among the patients, the bi-ventricular systolic pressure ratio correlated not only with the index in end systole but also with that in early diastole. Good correlation between systolic pressure ratio and early diastolic deformity index seemed to be attributable to the fact that the higher the RV systolic pressure, the larger the reversed pressure gradient between both ventricles in early diastole.(ABSTRACT TRUNCATED AT 400 WORDS)

Diastole↗
PubMed1984

[Studies on the reverse tolerance phenomenon after repeated methamphetamine treatment in rats].

Male rats of the Wistar strain were divided into three groups, to which three different doses of methamphetamine (MAP), 0.5 mg, 2 mg, and 4 mg/kg/day, respectively, were intraperitoneally administered 5 times per week for 36 days. Stereotyped behaviors were scored according to the method of Ellinwood & Balster. During the period of repeated MAP treatment, these behaviors increased in a dose dependent manner. Group I treated with 0.5 mg/kg of MAP demonstrated more prominently an increased sensitivity to MAP than the other two, Group II with 2 mg/kg and Group III with 4 mg/kg. Following the withdrawal period of 4 weeks, the rats were reinjected with 0.5 mg/kg of MAP. They showed higher scores of stereotypies than those treated acutely with MAP, that is, reverse tolerance for MAP was observed, although this phenomenon was not necessarily observed in a dose dependent manner for each variable of the behaviors. Lethal autonomic response was observed in Group I and II, in which animals appeared to have reverse tolerance for autonomic response to MAP reinjection in contrast to in Group III. It can be concluded that repeated administration of MAP induces stereotyped behaviors in a dose dependent manner, while autonomic response is not likely to form tolerance.

Animals↗
PubMed1984

[Echocardiographic manifestations of postinfarction perforation with extensive dissection of the interventricular septum: report of an autopsied case].

This is a report of the echocardiographic features of postinfarction perforation associated with dissection of the interventricular septum (IVS) in a 61-year-old woman. She had acute myocardial infarction and was admitted to a nearby hospital, and later admitted to our CCU because hemodynamic deterioration. On admission, she was somnolent and hypotensive (90/64 mmHg), with sinus tachycardia, marked cyanosis, and peripheral edema. On auscultation there were a harsh holosystolic murmur over the LLSB and moist rales in both lung fields. An ECG revealed extensive anterior and inferior infarctions. Catheterization data confirmed O2 step-up in the right ventricle. Two-dimensional echocardiograms demonstrated extensive dissection of the IVS characterized by an echo-free lumen extending from the apex to the cardiac base in the long-axis and partly reaching the left ventricular free wall in the short-axis with the concomitant paradoxical movement of the IVS. Autopsy disclosed marked hemorrhagic infarction and extensive dissection of the IVS forming a lumen (5 X 5.5 X 2 cm3) corresponding exactly to the echocardiographic free space. In addition, a shunt between the right and left ventricles was confirmed by the presence of two perforations near the apex on the right and left sides of the IVS, whose diameters were 6 and 10 mm, respectively.

Cardiomyopathies↗
PubMed1984

Increased anticonvulsant effect of phenytoin in aging BDF1 mice.

The anticonvulsant effect of phenytoin was examined in BDF1 mice of both sexes and various ages (6, 12, 24 and 30 months old) using the abolition of the tonic hindlimb extensor component of maximal electroshock seizure as the index. The minimal effective plasma concentration of phenytoin was significantly lower in 24- and 30-month-old mice compared with young adult (6 month old) mice. Similarly, all older groups (24 and 30 month old, both sexes) showed significantly lower minimal effective brain concentrations compared with respective younger (6 and 12 month old) animal groups. Studies using nearly 2-fold different intensities of electroshock (30 and 55 mA) showed almost identical results. The results provide evidence that, in adult mice, the brain becomes more sensitive with age to phenytoin with regard to its anticonvulsant effect.

Aging↗
PubMed1983

Protective action of diethyldithiocarbamate and carbon disulfide against renal injury induced by chloroform in mice.

Oral administration of diethyldithiocarbamate (DTC) and carbon disulfide (CS2) protected mice against CHCl3-induced kidney injury, as evidenced by normalization of delayed plasma phenolsulfonphthalein clearance, suppression of increased kidney calcium content and prevention of renal tubular necrosis. In CCl4-treated mice, in which liver microsomal monooxygenase activities were decreased markedly, and kidney microsomal aniline hydroxylase and p-nitroanisole demethylase activities were increased to about twice those of the untreated mice, renal toxicity of CHCl3 was greatly potentiated, and the latter effect was also blocked by both agents. DTC and CS2 per se markedly decreased kidney microsomal aniline hydroxylase and p-nitroanisole demethylase activities at 1 hr after oral administration, accompanying a moderate loss of cytochrome P-450 content, in both normal and CCl4-treated mice. The protection was not due to hypothermia, because pretreatment with DTC or CS2 (p.o.) also prevented the hypothermia induced by CHCl3. The mechanism of the protection may have involved inhibition of metabolic activation of CHCl3 in the kidney rather than in the liver.

Acute Kidney Injury↗
PubMed1983

A comparative study of polychlorinated dibenzofurans, polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin on aryl hydrocarbon hydroxylase inducing potency in rats.

The aryl hydrocarbon hydroxylase (AHH) inducing potency of toxic chlorinated aromatic hydrocarbons such as polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was studied in the young male Wistar rats. Alternatively, a technical PCDF mixture, 15 individual PCDF isomers or TCDD were administered i.p. in doses of 5 micrograms/kg; a PCB mixture was given in a dose of 50 mg/kg. The order of AHH inducing ability was TCDD greater than PCDFs much greater than PCBs in kidney, lung, and liver. In the prostate, thymus, and spleen, only TCDD enhanced the AHH activity. The AHH inducibility in the lung and liver, induced by 15 pure PCDF isomers with varying chlorine substitutions was also examined. Only 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-tetra-CDF) and 2,3,4,7,8-pentachlorodibenzofurans (2,3,4,7,8-penta-CDF) significantly induced the hepatic AHH activity (4- and 2-fold, respectively), while eight PCDF isomers, including these two, significantly enhanced the pulmonary AHH activity (6- to 30-fold). Taking into account both the potent AHH inducibility and the high bioaccumulation of these compounds, 2,3,7,8-tetra- and 2,3,4,7,8-penta-CDF should be given due attention with regard to environmental-related factors and the possibility of involvement in the etiology of "yusho" disease.

Animals↗
PubMed1983

Protective action of diethyldithiocarbamate and carbon disulfide against acute toxicities induced by 1,1-dichloroethylene in mice.

In male mice of ddY strain, a single dose of 1,1-dichloroethylene (1,1-DCE, 0.1 ml/kg, ip) produced severe renal damage at 24 hr, as evidenced by elevations in plasma urea nitrogen concentration and kidney calcium content and by massive renal tubular necrosis, while hepatic damage was less severe. A precipitous decrease in body temperature started as early as 30 min after administration of 1,1-DCE and lasted for 24 hr. Glutathione concentrations decreased in the liver and kidney, with a rebound increase seen in the former but not in the latter tissue. In carbon tetrachloride-poisoned mice, the renal toxicity of 1,1-DCE was markedly potentiated. Pretreatment with either diethyldithiocarbamate (DTC) or carbon disulfide (CS2) blocked all of these 1,1-DCE-induced toxic manifestations in normal and carbon tetrachloride-poisoned mice. Both agents, however, did not prevent the hypothermia induced by monochloroacetic acid or chloroacetyl chloride, proposed active metabolites of 1,1-DCE. Since DTC and CS2 inhibited hepatic and renal microsomal drug metabolizing enzyme activities (Masuda and Nakayama, 1982, 1983), it is probable that the protective action of DTC and CS2 against renal and hepatic injury induced by 1,1-DCE may be due to an inhibition of the metabolic activation of 1,1-DCE to its proposed epoxide in each organ. The action of DTC given po may be mediated by CS2 produced in the stomach. The hypothermia induced by 1,1-DCE may not result from a direct action of 1,1-DCE per se, but by its metabolites.

Animals↗
PubMed1983

Three-dimensional holographic display of images of otological specimens.

Three-dimensional displays of anatomical structures and clinical findings are very persuasive and instructive. Using multiplex holograms, we designed a display of three-dimensional images of otological specimens. Multiplex holograms, reported by Cross of the United States in 1975, enable reconstruction of three-dimensional moving images and are used for artistic display as well as for teaching in medicine and general education. Multiplex holograms were recorded in a two-step process. The first step is to make a series of original cine-pictures of an object from different horizontal directions, rotating it on a turntable. In the second step, one frame of the original film is recorded on a narrow strip hologram. All frames of the original film are recorded one after another and a complete multiplex hologram can be synthesized. In the reconstruction stage, the multiplex hologram is formed into a cylinder and illuminated from below by a small white light source. Reconstructions of the three-dimensional bright images of the object inside the cylindrical holographic screen are shown.

Ear↗