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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 865 records · Page 48Linked to original sources
PubMed1981

A mixed tumor of the omentum majus in an adult with discussion related to hepatoblastoma.

A mixed tumor of the omentum majus found at autopsy of a 28-year-old man with a huge liver tumor is described. The primary tumor was identified in the omentum majus by macroscopic, histologic and electron-=microscopic observations. The tumor was finally diagnosed as a mixed tumor which resembled a hepatoblastoma consisting of immature and embryonal types of epithelial component and of mesodermal tumor including hemangioma, osteoid and myxomatous tissues in the primary lesion. Widespread multiple metastases of the epithelial component mainly to the liver, and partially in the lungs, diaphragm and lymph nodes were noted. The levels of alpha-fetoprotein and carcinoembryonic antigen were within normal limits, but the epithelial component showed a resemblance to primitive hepatocytes. This tumor was discussed related to hepatoblastoma in an adult, with the features compatible with description of the same tumors reported previously in the literature.

Adult↗
PubMed1981

Macular amyloidosis with patchy filamentous degeneration of collagen islands.

Unusual patchy filamentous degeneration of collagen islands, found in a typical case of macular amyloidosis, is described. This phenomenon was found to begin in intact islands scattered among the amyloid islands in the papillary and upper reticula dermis. Since the patches varied in size, they were thought to have grown gradually with time. They were derived from the degeneration of collagen fibrils and demonstrated a tropocollagen-like structure. Although the small patches preserved some characteristic structures of collagen fibrils or tropocollagen, the large patches showed amyloid-like filamentous masses surrounding the collagen islands.

Amyloidosis↗
PubMed1981

Mechanism of glycogenosome formation in axons of cadmium-induced neuropathy--ultrastructural and biochemical studies.

Numerous glycogenosomes were found in the axoplasm of the sciatic nerves in neuropathy induced by the long-term administration of cadmium to rats. The glycogen particles in the glycogenosomes were larger than those deposited in the intracytoplasmic matrix. Two forms of alpha-glucosidases, acid and neutral, were found in the sciatic nerve of normal rat. Cadmium ions inhibited the activity of the neutral alpha-glucosidase by a maximum of 24.0%, while acid alpha-glucosidase was not inhibited. Hg ions completely inhibited both forms of alpha-glucosidases; however, it has been reported that no glycogenosomes appear in Hg++-induced neuropathy. It was considered that the inhibitory effect of cadmium on the neutral alpha-glucosidase led to the enlargement of glycogen particles, and the large glycogen molecules were then engulfed in the lysosome system.

Animals↗
PubMed1981

Elastotic material and elastic fibers in aged skin: an ultrastructural study with conventional and tannic acid stain.

Elastotic material and aged elastic fibers were studied with an electron microscopy, using both conventional and tannic acid stain. (1) A relatively large part of the fibrous form, and a lesser part of the amorphous form stained positive with the tannic acid stain. (2) Aged elastic fibers showed some age-related findings with both conventional and tannic acid staining. It is suggested that the elastotic material originates from the elastic fibers and progresses from the fibrous to the amorphous form.

Age Factors↗
PubMed1980

Quantitative electromyographic diagnosis of myofascial pain-dysfunction syndrome.

The slopes of the V/T curves of masticatory muscles were determined in patients with MPD syndrome, and the changes in the slopes were observed prior to and during electrical muscle stimulation and splint therapy. The slopes of the V/T curves in patients with MPD syndrome were significantly steeper than those of the healthy subjects. In patients with MPD the slopes were decreased by electrical muscle stimulation of moderate duration and by insertion of the splint. These findings suggest that the most simple procedure for the diagnosis of MPD syndrome is to compare the slopes in MPD patients with those of healthy subjects. The observation of the changes in slopes during electrical muscle stimulation and splint therapy permits a more quantitative diagnosis of MPD syndrome. It also permits a quantitative measurement of improvement of symptoms in patients with MPD syndrome.

Adult↗
PubMed1980

Effect of occlusal splints on the electromyographic activities of masseter muscles during maximum clenching in patients with myofascial pain-dysfunction syndrome.

Integrated EMG activities of masseter muscles during maximum voluntary isometric contraction with and without full-arch maxillary stabilization splints were observed in patients with MPD syndrome having occlusal interferences and in healthy subjects having no occlusal interferences. The masseter muscle activity was more significantly reduced in patients with MPD syndrome during maximum clenching with splints than in those patients without splints. In healthy subjects, such a significant difference could not be observed with and without splints. This finding suggests that the elimination of the occlusal interferences by means of occlusal splints could reduce the degree of sensory information from the periodontal receptors during nocturnal clenching or grinding. This could result in a decrease in masseter muscle activity giving rise to muscular relaxation.

Action Potentials↗
PubMed1980

Gaze control in cats achieved by rewarding tongue push movements during the flickering of a light-emitting diode.

A method is described for achieving gaze control in cats, by rewarding them for pushing against a lever with their tongue, only when a light-emitting diode (LED) was flickering. Since the state of the LED was changed sequentially from OFF to ON to flickering and the duration of flickering was short, the cats were required to gaze continuously at the LED during its ON period, in order to detect the flickering. After the preliminary training stage, 2-3 weeks were required before the cats performed the task at a higher level than could be predicted by chance. The electro-oculogram indicated that the eyes fixated during the ON period of the LED.

Animals↗
PubMed1980

Physicochemical and ultrastructural studies on glycogenosomes in newborn rat hepatocytes.

In the newborn rat liver, glycogenosomes appeared at about 6 hours after birth and gradually increased in number, despite high activity of lysosomal acid alpha-glucosidase. The glycogenosomes then disappeared completely with 2 days after birth. Glycogen extracted from fetal rat liver differed in molecular structure from that of adult rat liver. In measurements of optical rotatory dispersion (ORD) and circular dichroism (CD) absorption spectra, fetal-type glycogen showed the Cotton effect whereas the adult rat liver glycogen did not. The degree of branching and S-values of the two glycogens were also different. With the disappearance of glycogenosomes, fetal-type glycogen disappeared completely, and adult-type glycogen then appeared strongly. This was demonstrated in the intracytoplasmic matrix by electron microscopy. The present experiments indicate that glycogenosomes may be formed even under conditions of high acid alpha-glucosidase, and that autophagy of glycogen macromolecules in the lysosomal system is closely related to different structural features of fetal-type glycogen in the neonatal period.

Animals↗
PubMed1980

Ultrastructural and biochemical studies of glycogenosome formation in ascites hepatoma AH 13 cells.

Appreciable numbers of glycogenosomes were found in ascites hepatoma cells. They were lined by a single or sometimes double membranous structure exhibiting weakly positive acid phosphatase activity. Some were closely related to the Golgi apparatus, and a few showed wrapping of glycogen particles. The glycogen extracted from ascites hepatoma AH 13 cells was of two major types: a normal adult liver type, and a muscle type. Only the latter type gave the Cotton effect on measurement of the ORD and CD spectra. Small particulate, muscle type glycogen was observed in the glycogenosomes. Autophagy of normal adult liver type glycogen was never found. The engulfment of muscle type glycogen was accompanied by high acid and neutral alpha-glucosidase activity levels.

Acid Phosphatase↗