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Biomedical subjects

Y Miyata

Publications and source records attributed to Y Miyata.

At least 235 records · Page 13Linked to original sources
PubMed1989

[A case of membranous septal aneurysm associated with infective endocarditis].

A 43-year-old man with membranous septal aneurysm associated with infective endocarditis was reported. In this case, the stream of the shunt through VSD was directly oriented toward the atrial surface of the tricuspid anterior cusp and made it unusual form. The focus of infective endocarditis was located on that cusp, and he underwent tricuspid valve replacement with VSD closure. The post-operative course was uneventful. We discussed the tricuspid anterior cusp deformed by the jet stream of the shunt and the relationship between the aneurysm and the infective endocarditis.

Adult↗
PubMed1989

[Blind-ending bifid ureter: report of a case].

A case of blind-ending bifid ureter is presented. A 65-year-old man was admitted with the complaint of dysuria. He had no past episode of left flank pain or pyelonephritis. Digital examination and urethrography suggested benign prostatic hypertrophy. Drip infusion pyelography showed an abnormal cavity at the lower portion of the left ureter. He was diagnosed as benign prostate hypertrophy and left blind-ending bifid ureter. During suprapubic prostatectomy, the bifid ureter was resectd. The related reports are reviewed in the Japanese literature.

Aged↗
PubMed1989

[A case of two staged operation of pericardial abscess after left-ventricular aneurysmectomy].

A 54-year-old man who had undergone the left ventricular aneurysmectomy and double saphenous vein bypass grafting for the old myocardial infarction suffered from the pericardial abscess 6 years after the first operation. He was operated upon the persistent drainage of the lesion and returned to his daily life. Two years after the 2nd operation, he recognized pulsatile bleeding from the fistula and was admitted to our hospital. He underwent the radical operation for the cardio cutaneous fistula under the cardiopulmonary bypass. The post operative course was uneventful and he has continued to do well. We discussed the treatment for this kind of complication and stressed the limited usage of Teflon felt and other artificial materials.

Abscess↗
PubMed1988

Protein-kinase-C-catalyzed phosphorylation of the microtubule-binding domain of microtubule-associated protein 2 inhibits its ability to induce tubulin polymerization.

It has previously been demonstrated that microtubule-associated protein 2 (MAP2) is a good substrate for the purified protein kinase C [Tsuyama, S., Bramblett, G. T., Huang, K.-P. & Flavin, M. (1986) J. Biol. Chem. 261, 4110-4116; Akiyama, T., Nishida, E., Ishida, J., Saji, N., Ogawara, H., Hoshi, M., Miyata, Y. & Sakai, H. (1986) J. Biol. Chem. 261, 15648-15651]. We have shown here that phosphorylation of MAP2, catalyzed by protein kinase C, reduces the ability to induce tubulin polymerization. MAP2 is divided into two domains by digestion with alpha-chymotrypsin; the microtubule-binding and the non-binding (projection) domains. The limited chymotryptic digestion following phosphorylation of MAP2 by protein kinase C has shown that both the domains of MAP2 were phosphorylated by protein kinase C, 50-60% of the incorporated phosphates being detected in the microtubule-binding domain. Polypeptide fragments, containing the microtubule-binding domain of MAP2, were purified by DEAE-cellulose column chromatography after chymotryptic digestion of MAP2. The purified microtubule-binding fragments were competent to polymerize tubulin, and served as good substrates for protein kinase C. The phosphorylation of the microtubule-binding fragments by protein kinase C reduced their ability to induce tubulin polymerization. These results suggest that the ability of MAP2 to induce tubulin polymerization is inhibited by phosphorylation of the microtubule-binding domain catalyzed by protein kinase C.

Actins↗
PubMed1988

Increased accumulation of iodine-123-IMP in the pulmonary inflammatory lesion surrounding a lung cancer.

In a patient with primary lung cancer, increased accumulation of I-123-IMP was observed in a pulmonary inflammatory lesion surrounding a lung cancer which was delineated as a photon deficient area. Ga-67-citrate uptake was observed in both the inflammatory and cancerous areas. These findings suggest that I-123-IMP may have the potential to accumulate differently in a variety of pathological conditions of the lung and thus may be a clinically useful lung imaging agent.

Amphetamines↗
PubMed1988

Growth factor- and phorbol ester-induced changes in cell morphology analyzed by digital image processing.

We have developed the computer-aided image processing analysis to visualize and quantitate the cell motility and morphological changes in living cultured cells. The effect of growth factors on cell motility and morphology has been analyzed by this method. Insulin, insulin-like growth factor-I (IGF-I), and epidermal growth factor (EGF) elicited membrane rufflings in rat embryo fibroblast 3Y1 cells as well as in human epidermoid carcinoma KB cells. Insulin and IGF-I also induced ruffling membranes in Balb/c-3T3 cells. The quantitative analysis by the programmed trace mode of the AVEC system has shown that the motion of the membrane rufflings was observed within 2 min, reached the maximum level within 4-8 min, and rapidly decreased within 10-15 min after the addition of these growth factors. The analysis also revealed the temperature- and growth factor concentration-dependent changes in the motion of membrane rufflings elicited by these growth factors. 12-O-Tetradecanoylphorbol-13-acetate, one of the well-known tumor promoters, rapidly induced cell rounding in Balb/c-3T3 cells. This change of cell morphology could be also quantified by the trace mode analysis. The fluorescent phalloidin staining experiment indicated that these growth factor- or phorbol ester-induced morphological changes were accompanied by the reorganization of filamentous actin. Furthermore, we were able to visualize actin stress fibers in living EBTr cells by enhancing the video image and to follow the reduction of stress fibers induced by cytochalasin B without any fixation or fluorescent probes.

Actins↗
PubMed1988

Rapid stimulation of fluid-phase endocytosis and exocytosis by insulin, insulin-like growth factor-I, and epidermal growth factor in KB cells.

Effects of growth factors on fluid-phase endocytosis and exocytosis in human epidermoid carcinoma KB cells were examined by measuring horseradish peroxidase (HRP) as a marker. Insulin, insulin-like growth factor-I (IGF-I), and epidermal growth factor (EGF) promoted HRP accumulation. They also stimulated the efflux of the preloaded HRP from the cells. From these results it follows that these growth factors stimulate the influx as well as the efflux of HRP, because the accumulation rate is the sum of the influx rate and the efflux rate. The stimulation of both HRP accumulation and HRP efflux was rapidly induced within 2-4 min of the addition of growth factors and persisted for at least 60 min. The concentrations eliciting half-maximal stimulatory effects of insulin, IGF-I, and EGF were about 5 X 10(-7), 1 X 10(-9), and 5 X 10(-10) M, respectively. aIR-3 (anti-type I IGF receptor antibody) completely blocked the stimulation of HRP accumulation by IGF-I but very slightly inhibited the stimulation by insulin. The 528 IgG (anti-EGF receptor antibody) inhibited the stimulation of HRP accumulation by EGF. These results indicated that each of these growth factors stimulates the HRP accumulation mediated by the corresponding (homologous) growth factor receptors. The rapid stimulation of fluid-phase influx and efflux may constitute one of the common early cellular responses to growth factors.

Antibodies↗
PubMed1988

Enhancement of Ia synaptic transmission following muscle nerve section: dependence upon protein synthesis.

Monosynaptic excitatory postsynaptic potentials (EPSPs) were recorded from the triceps surae motoneurons in the rat. Two to 3 weeks after section of the medial gastrocnemius (MG) nerve, Ia EPSPs evoked by stimulation of the MG nerve were significantly depressed, as reported previously. However, the MG EPSP amplitude significantly increased within 24 h, reaching a maximum on the 3rd day after axotomy. This increase was prevented by actinomycin-D treatment, indicating that the synaptic enhancement is dependent upon protein synthesis. When disuse of sensory fibers was induced without injuring the muscle nerve, the degree of synaptic enhancement was similar to that after axotomy. Therefore, the enhancement of central synaptic transmission shortly after axotomy is due to the loss of electrical activity, but not due to the axon reaction of the Ia sensory neurons to injury. It is postulated that the presence of some factor in Ia sensory fibers enhances synaptic transmission, while electrical activity of the neurons antagonizes the action of this factor.

Animals↗
PubMed1988

[Assessment of the discriminant analysis concerning the prognostic factors in patients with differentiated thyroid cancer].

We reported the result of our discriminant analysis concerning prognostic factors in differentiated thyroid cancer, which based on 134 cases obtained from three hospitals. The sensitivity, specificity and false-negative rate were 59%, 61% and 22%, respectively. When these values were estimated individually in each hospital, the figures were better than those obtained from a whole group of patients. The purpose of this paper is to assess the reliability of the previous result. Simulation was done to assess the relationship between the number of patients and the ratio of criterion variables. New groups were made from the 134 patients by random sampling. In each group, discriminant analysis was done by using the same nine explanatory variables as in the previous report (age, sex, diameter of tumor, site of tumor, histology, local invasion, lymph node metastasis, operative method and lymph node dissection). The results revealed that sensitivity was relatively stable but specificity and false-negative rate were better in the smaller group of patients. The ratio of criterion variables had an effect on the results. In the higher ratio, sensitivity was higher and the false-negative rate was lower.

Adenocarcinoma↗
PubMed1988

Hepatic encephalopathy and reversible cortical blindness.

We report a case of recurrent hepatic encephalopathy accompanied by transient cortical blindness. The patient with cryptogenic liver cirrhosis had six attacks of hepatic encephalopathy of grades II to III during 1 yr after admission. In the beginning of each episode of encephalopathy, when the patient was conscious, a complete loss of vision occurred, but with a normal pupillary reflex to light. At the same time, the visual evoked potential recorded the second negative wave with a prolonged latency and a diminished amplitude. His sight completely returned, and the electroencephalogram tracing and the visual evoked potential response normalized after treatment for the encephalopathy. The loss of vision was thought to be cortical blindness accompanied by hepatic encephalopathy. Thus, in rare cases of hepatic encephalopathy, the visual cortex may be affected, and cortical blindness may occur before the loss of consciousness.

Blindness↗
PubMed1987

Tyrosine phosphorylation by the epidermal growth factor receptor kinase induces functional alterations in microtubule-associated protein 2.

We have examined the effect of tyrosine phosphorylation of microtubule-associated protein 2 (MAP2) by the epidermal growth factor (EGF) receptor kinase on its functions. Incubation of MAP2 with the EGF receptor in the presence of ATP resulted in a great decrease in the ability of MAP2 to promote tubulin polymerization. Under a variety of conditions, the decrease in the ability correlated with the extent of phosphorylation of MAP2. Furthermore, another function of MAP2, the actin filament cross-linking activity, was also inactivated by the incubation of MAP2 with the EGF receptor and ATP. The loss of this activity also correlated well with the extent of phosphorylation. These data indicate that tyrosine phosphorylation of MAP2 by the EGF receptor kinase inactivates both the tubulin polymerizing activity and actin filament cross-linking activity of MAP2. Thus, this study has clearly shown that tyrosine phosphorylation could modify the function of a cytoskeletal protein.

Actins↗