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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 775 records · Page 43Linked to original sources
PubMed1984

A method for calibrating the gain of the electro-oculogram (EOG) using the optical properties of the eye.

A method has been developed to measure the gain of the electro-oculogram (in volts per degree of eye rotation) which does not require the experimental subject to gaze at reference targets. The basis of the method is that the positional difference between the center of the entrance pupil and the corneal reflection of a light source is linearly related to the angle of eye rotation and is equal to zero when the pupillary axis of the eye is directed at the light source. The method has been validated in man and cat.

Calibration↗
PubMed1984

Effects of nutrition and ontogeny on liver cytosolic and mitochondrial phosphoenolpyruvate carboxykinase activity of the rat, hamster, guinea-pig, pig, kid, calf and chick.

In rat, hamster, guinea-pig, pig, kid, and calf liver, starvation or carbohydrate starvation increased cytosolic phosphoenolpyruvate carboxykinase activity without changing the mitochondrial activity whereas in chick liver, starvation did not alter the activity in both fractions. Liver glycogen content changed in a reciprocal way to the cytosolic phosphoenolpyruvate carboxykinase activity. In prenatal kid and chick liver, phosphoenolpyruvate carboxykinase activity appeared in both cytosolic and mitochondrial fractions, and in chick liver, considerable increase of the cytosolic activity was observed from a few days before hatching to 4 days after hatching.

Aging↗
PubMed1984

Noxious stimuli and Met-enkephalin release from nucleus reticularis gigantocellularis.

The nucleus reticularis gigantocellularis of the rat medulla oblongata was perfused in situ, and effects of noxious stimuli on the release of immunoreactive Met-enkephalin were examined. Formalin-induced and thermal but not mechanical stimuli increased the "tonic" release of immunoreactive Met-enkephalin from this nucleus. No "phasic" increase was observed following the three forms of stimulation. A topical application of dibucaine abolished the formalin-induced increase in the release of immunoreactive Met-enkephalin. Therefore, the possibility that persistent noxious stimuli may activate the Met-enkephalin-containing fibers in the nucleus reticularis gigantocellularis has to be given consideration.

Animals↗
PubMed1984

Sequential production of Birbeck granules through adsorptive pinocytosis.

A case of vitiligo with inflammatory raised borders was observed electron microscopically, resulting in an interesting view of the formation of Birbeck granules in Langerhans cells. Following the formation of larger coated vesicles, which perform adsorptive pinocytosis from the cell membrane, membrane invagination of the cell occurred shown as the tubular infolding, resulting in the observation of the characteristic Birbeck granule band pattern in its interior. This phenomenon supports the theory of Hashimoto and Tarnowski (1968) that Birbeck granules are formed from the infolding of the cell membrane. In addition, our study shows the involvement of adsorptive pinocytosis in the formation of the granules. It was suggested that when the coated Birbeck granule shifts into the cell, possibly its coat is detached and the vesicle portion forms the globule of the Birbeck granule.

Adult↗
PubMed1984

An ultrastructural study of pretibial myxedema utilizing improved ruthenium red stain.

A case of pretibial myxedema associated with Graves' diseases has been studied by electron microscopy utilizing an improved ruthenium red stain. An organized network of microfibrils with knobs were found within the widened interfibrous spaces. This network was clearly demonstrated by the ruthenium red stain, but only a weak trace could be observed when conventional staining techniques were utilized. Knobs of the network seemed to be composed of ruthenium red-positive granules which surrounded normal fibers and granules of degrading collagen fibers. Many fibroblasts showed dilated rough endoplasmic reticulum containing much amorphous material which indicated a significant role of fibroblasts in the pathogenesis of this disease.

Aged↗
PubMed1984

The use of improved ruthenium red staining for the ultrastructural detection of proteoglycan aggregates in normal skin and lichen myxoedematosus.

Improved ruthenium red staining has been applied to normal human skin and lichen myxoedematosus skin lesions for the detection of the fine structure proteoglycan aggregates. In 4 samples of normal skin and in a patient with lichen myxoedematosus, the typical fine ultrastructures of proteoglycan aggregates, i.e., many short irregularly-curled filaments of varying lengths attached to long and rather straight filaments of hyaluronic acid were shown. Although lichen myxoedematosus is thought to be due to the faulty formation of proteoglycan aggregates, we suggest a different view, that this improved method of ruthenium red staining is useful for the detection of proteoglycan aggregates, and provides a better preparation for electron microscopy.

Humans↗
PubMed1984

High melanosome engulfing activity of cutaneous fibroblasts in macular amyloidosis: an electron microscopic study.

Six patients with macular amyloidosis were investigated by electron microscopy and various morphological changes in fibroblasts were identified. Many cells, which seemed to be macrophages by light microscopy, proved to be fibroblasts. The digesting action of fibroblasts was well developed and many melanosomes were taken into the cells making the cells resemble melanophages. The fibroblasts extended long, thin and branched cytoplasmic processes to surround the amyloid mass, and the cells selectively extended these into the narrow spaces between collagen and amyloid. The fibroblast showed highly developed endocytotic activity and probable ingestion of amyloid by pinocytosis or phagocytosis. The developed rough endoplasmic reticulum contained much protein and was active in secretion.

Amyloidosis↗
PubMed1984

Structure of Cell Wall and Extracellular Mannans from Saccharomyces rouxii and Their Relationship to a High Concentration of NaCl in the Growth Medium.

Cells of Saccharomyces rouxii (a salt-tolerant yeast) were grown in the presence of two levels of NaCl, 0 and 15%. Mannans obtained from both the cell walls and culture filtrates (extracellular) were examined. Yields based on the dry weight of cells demonstrated that the levels of both cell wall and extracellular mannans were lower when cells were grown in the presence of 15% NaCl. However, the carbohydrate and protein contents of the mannan preparations were not altered. The cell wall mannans obtained from the two growth conditions had similar molecular weights, whereas the extracellular mannans had different molecular weight distributions. Structural analyses showed that the cell wall and extracellular mannans had similar structures. Both had an alpha1-6-linked backbone to which single mannose and mannobiose units were connected as side chains, predominantly by alpha1-2 linkages. The mannans also contained mannosyloligosaccharides, mannotriose, mannobiose, and mannose attached to protein through an O-glycosidic bond. The molecular structure of the cell wall mannans remained unchanged at both levels of NaCl. However, in the presence of 15% NaCl, the side chains consisting of a mannobiose unit were slightly reduced.

Journal Article↗
PubMed1984

A variant of encephalomeningocele: heterotopic brain tissue on the scalp.

A 2-year-old girl having a bald nodule on the scalp is reported. The tumor was circular, hemispherically elevated and had a dull reddish color. Roentgenologic studies revealed a defect of the underlying skull bone, and spina bifida occulta on the first and second sacral vertebra were found. Craniotomy was carried out. The tumor extended into the falx cerebri and reached to the tentorium cerebelli, and was not connected with the cerebrum. Histological examination showed insular brain tissue containing glial cells in the lower dermis. Around this tissue, there seemed to be vascular leptomeninges with numerous melanocytes and thickened fibrous elements, probably dura. From these findings, this case was diagnosed as a variant of encephalomeningocele, and as melanocytes physiologically exist on the leptomeninges, melanocytes in an encephalomeningocele may diagnostically identify the leptomeninges.

Calcinosis↗
PubMed1984

Counteractive effects of propionate or 1,2-propanediol against hypoglycemia and ketonemia of tributyrin-treated cows.

We administered tributyrin (500 ml), tributyrin (500 ml) plus magnesium propionate (400 g), tributyrin (500 ml) plus sodium propionate (400 g), or tributyrin (500 ml) plus 1,2-propanediol (400 ml) as a single dose into rumens of lactating cows and then measured in blood the plasma concentrations of glucose, acetoacetate, 3-hydroxybutyrate, free fatty acids, and insulin as a function of time. Tributyrin administration caused hypoglycemia and hyperketonemia similar to the ketotic condition in less than 3 h and was a negative correlation of --.88 between glucose and ketone concentrations in blood plasma. Administration of either magnesium propionate, sodium propionate, or 1,2-propanediol could counteract the hypoglycemia and hyperketonemia induced by tributyrin administration without significantly changing the insulin response. Of the two propionate compounds, magnesium propionate was more effective than sodium propionate for alleviating hypoglycemia and hyperketonemia.

3-Hydroxybutyric Acid↗
PubMed1984

Effects of vitamin E in kid erythrocytes on Tween 20-induced hemolysis in vitro.

Red blood cells (RBC) of alpha-tocopherol sufficiency and deficiency were produced in kids fed on purified diets to investigate the relationship between RBC alpha-tocopherol levels and hemolysis induced by Tween 20. RBC alpha-tocopherol contents of vitamin E-deficient kids were non-detectable from 4 weeks, and percentages of hemolysis increased to over 70%. A highly significant decrease in hemolysis was noted when vitamin E was added to the diet. Tween 20 hemolysis values were negatively correlated with RBC tocopherol levels in kids. The concentration of RBC alpha-tocopherol required to prevent the hemolysis was found to be 0.6 microgram/ml packed cells.

Animals↗
PubMed1984

Evaluation of cutaneous amyloid employing anti-keratin antibodies and the immunoperoxidase technique (PAP method).

Thirty-one cases of primary cutaneous amyloidosis were studied by the immunoperoxidase technique (PAP method) employing anti-keratin antibodies. All specimens were examined using consecutive paraffin sections to confirm the correspondence between amyloid existing area and reactive sites. All of the sections examined were non-reactive in amyloid deposited sites whereas the epidermis always showed strong reaction with anti-keratin antibodies.

Amyloid↗
PubMed1984

Mondor's phlebitis of the penis: a study with factor VIII related antigen.

Four patients with so-called non-venereal sclerosing lymphangitis of the penis are reported. It was suggested that the affected vessels were veins by positively stained factor VIII related antigen with the unlabeled peroxidase-antiperoxidase method. If cord-like linear subcutaneous swelling observed in the coronary sulcus or dorsal region of the penile shaft originate from the vein, it seems correct to call this disease as Mondor's phlebitis of the penis.

Adult↗