Biomedical subjects

H Hakata

Publications and source records attributed to H Hakata.

11 recordsLinked to original sources

PubMed1992

Hyalinizing trabecular adenoma.

A case is presented of hyalinizing trabecular adenoma in a 54-year-old Japanese female. The patient underwent a hemithyroidectomy for the diagnosis of thyroid carcinoma. An intraoperative frozen section diagnosis was medullary carcinoma. Hematoxylin and eosin stained permanent sections from the surgical specimen, a well encapsulated 3.0 x 2.0 x 1 cm nodule, also led us to suspect medullary carcinoma, but immunohistochemical staining for thyrocalcitonin, CEA, and thyroglobulin showed that it was a hyalinizing trabecular adenoma.

Adenoma↗

PubMed1987

A new blood pressure measuring apparatus equipped with a microcomputer system for conscious rats.

In order to measure the systolic blood pressure of conscious rats without thermal stress, a highly sensitive pulse sensor was developed using a light-emitting diode-photo diode system. The combination of this pulse sensor and microcomputer system led to the development of a six-channel automatic blood pressure measuring apparatus for rats. It can measure the systolic tail arterial pressure of conscious rats at 28-30 degrees C. The relationship between direct carotid arterial pressure (Y) and indirect tail arterial pressure (X) in conscious spontaneously hypertensive rats can be expressed as follows: Y = 0.95X + 19.9 (mm Hg, r = 0.988, 28 degrees C). The new apparatus was also used to confirm the acute hypotensive effects of hydralazine, nifedipine, and pindolol in spontaneously hypertensive rats and the subacute antihypertensive effect of trichlormethiazide in desoxycorticosterone/saline hypertensive rats.

Animals↗

PubMed1985

Hydrolysis of polyphosphoinositides in human platelets.

Phospholipase C was purified 110 fold from human platelets. The activity of the enzyme was totally dependent upon Ca2+. The activity of the enzyme was markedly enhanced in the presence of arachidonic acid and was strongly inhibited by aminoglycoside antibiotics. The enzyme hydrolyzed endogenous polyphosphoinositides in addition to PI in Ca2+ dependent manner, suggesting the involvement of this enzyme in stimulus-linked rapid hydrolysis of polyphosphoinositides in platelets. The stimulation by thrombin of 32P-labelled human platelets induced about 30% decrease in 32P-TPI and about 220% increase in 32P-PA at the first 10 sec. The degree of hydrolysis of TPI was dependent upon the amount of agonist and it was not affected by the extracellular concentration of Ca2+. The changes in 32P-phospholipids in thrombin-stimulated platelets in the absence of Ca2+ were inhibited in a dose dependent manner by preincubation with relatively higher amount of quin 2 AM. The inhibition was completely overcome by an addition of CaCl2 to the suspending buffer. By such treatment in the absence of extracellular Ca2+, the intracellular Ca2+ concentration was significantly lowered below the basal level (less than 100 nM). Those observations suggest that TPI breakdown in thrombin-stimulated platelets is primary mediated by the agonist receptor coupling and requires at least the basal level of intracellular Ca2+.

Aminoquinolines↗

PubMed1982

Purification and characterization of phosphatidylinositol-specific phospholipase C from bovine platelets.

Phosphatidylinositol-specific phospholipase C was purified to homogeneity from soluble fraction of bovine platelets by ammonium sulfate fractionation, hydrophobic chromatography, DEAE ion exchange chromatography and gel filtration. The purified enzyme has a narrow pH optimum ranging from 6.5 to 7.5 and the molecular weight of the enzyme was estimated to be 143,000 by sodium dodecyl sulfate slab gel electrophoresis. The purified enzyme requires Ca2+ strictly for activity, which was markedly enhanced in the presence of arachidonate. No enhancement of the activity was observed in the presence of purified calmodulin. The activity was markedly inhibited in the presence of quinacrine but no inhibition by indomethacin was observed.

Animals↗

PubMed1976

Bilateral carcinoma of the ears. Report of a case.

We report a rare case of bilateral carcinoma of the ears in a 41-year-old man. The second tumor developed from the left mastoidectomized middle ear cavity eight years after the complete healing of the first tumor, which probably originated in the glands of the right external auditory canal.

Adult↗

PubMed1971