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Biomedical subjects

K Hirota

Publications and source records attributed to K Hirota.

At least 415 records · Page 23Linked to original sources
PubMed1988

[Detection of left ventricular thrombi after acute myocardial infarction using Ga-67-DFO-DAS-fibrinogen].

Ga-67-DFO-DAS-fibrinogen (Ga-fbg) scintigraphy, a new radiopharmaceutical method, was performed for detecting intraventricular thrombi following acute myocardial infarction in five patients. The thrombi in four of them were detected by two-dimensional echocardiography (2DE) and that in the fifth patient was suspected during magnetic resonance imaging. Imaging of the heart was performed using a scinticamera with a medium energy collimator and multiple views (anterior, LAO 30 degrees, LAO 45 degrees, and lateral) three and four days after the intravenous administration of Ga-fbg. By Ga-fbg scintigraphy, intraventricular thrombi were detected in four patients. The size of the thrombi visualized by Ga-fbg appeared larger than those by 2DE. In one patient examined again after anticoagulant therapy, a thrombus was missed by 2-DE, but it was detected by Ga-fbg, though the radioactivity of the thrombus decreased. We concluded that Ga-fbg scintigraphy is a very simple method and sufficiently useful for detecting active left ventricular thrombi and for monitoring the effect of anticoagulant therapy. It could be more sensitive than 2DE for determining the extent of an active intraventricular thrombus.

Adult↗
PubMed1987

A new glucocorticoid receptor detected in host rat liver but not in various hepatomas.

Previously a new glucocorticoid receptor (Peak C), which eluted with 0.12 to 0.14 M NaCl from DEAE-cellulose column, was identified in addition to another receptor (Peak B), a classic type of glucocorticoid receptor, which eluted with 0.05 to 0.08 M NaCl. Peak C appeared after stress or injection of a high dose (20 micrograms/100 g body weight) of dexamethasone into rats. Peak C was also detected in the liver of rats bearing various tumors, but it was not found in malignant tumors (Yoshida sarcoma and Yoshida ascites hepatoma AH 130), a less malignant Yoshida ascites hepatoma (LY-5), or in minimal deviation-type hepatomas (Morris hepatomas 7316A and 7794A). The absence of Peak C in these tumors coincided with the inability of the glucocorticoid to induce tryptophan oxygenase in these tumors and in the liver of rats during early postnatal development. Peak B was consistently observed in various hepatomas and immature rat liver with capability to induce tyrosine aminotransferase. Thus Peak C appeared to be a highly differentiated type of glucocorticoid receptor mediating specific hormone actions and to be present in mature liver cells, but not in immature liver or tumor cells, even of the minimal deviation type.

Animals↗
PubMed1987

Purification and partial characterization of adenosine diphosphatase activity in bovine aorta microsomes.

Anti-aggregatory activities in bovine aorta microsomal fractions were solubilized with Triton X-100 and separated into two fractions by DEAE-Sepharose CL-6B. One fraction strongly inhibited arachidonic acid-induced platelet aggregation, and the other inhibited ADP-induced aggregation. The latter fraction contained ADPase activity. The ADPase activity was further purified by affinity chromatography. The purified enzyme had specific activities of 43.8 and 48.2 mumol of Pi/min/mg protein for ADP and ATP, respectively. The enzyme required calcium or magnesium ions and it was insensitive to ATPase inhibitors, namely oligomycin and ouabain, and to adenylate kinase inhibitor, Ap5A. Polyacrylamide gel electrophoretic experiments indicated that only one enzyme was involved. This was confirmed by the parallel behavior of ADPase and ATPase activities throughout all the purification steps. These results suggest that the main anti-aggregatory activity of bovine aorta microsomes for ADP-induced aggregation is due to an ATP diphosphohydrolase (EC 3.6.1.5).

Adenosine Diphosphate↗
PubMed1987

Isolation of N-phenylprotoporphyrin IX from the red cells and spleen of the phenylhydrazine-treated rat.

Blood and spleens of phenylhydrazine-injected rats were treated with a solution of acidic methanol and zinc ion to isolate a green pigment. The pigment was resolved into two, I and II, by thin-layer chromatography. Pigment I was a mixture of two isomers of zinc complex of esterified N-phenylprotoporphyrin IX, in which vinyl-substituted pyrrole rings A and B were phenylated; and pigment II was a mixture of two isomers of the porphyrin complex with the N-phenyl group on propionic acid-substituted rings C and D. These pigments were also chemically prepared from the reaction of phenylhydrazine with oxyhemoglobin, independently characterized, and used to confirm the structures of the biological pigments. Determination revealed that the total amount of pigments found in the blood and spleen at 24 h after injection of phenylhydrazine corresponds to about 0.4% of the injected phenylhydrazine.

Animals↗
PubMed1987

Inhibitory effect of immobilized microsomal proteins on platelet aggregation.

Bovine aorta microsome was solubilized by 0.5% Triton X-100, and then immobilized on agarose gel (Sepharose 4B). Immobilized microsomal proteins (I-MP) inhibited platelet aggregations induced by ADP, arachidonic acid, collagen, and thrombin. The decrease of free platelet count in sheared whole blood was suppressed by I-MP. The anti-aggregatory activity of I-MP on arachidonic acid-induced aggregation was inhibited by 15-HPETE. This result suggests that I-MP contains PGI2 synthetase activity. It is considered that immobilization of enzymatic systems in aorta microsome which limited platelet aggregation is effective to provide an antithrombogenicity to the artificial polymers for artificial organs, especially used under the conditions which frequently induced platelet aggregation.

Animals↗
PubMed1987

Effect of clomiphene citrate administration during the early luteal phase on the luteal function and pregnancy rate of women.

To study the effect of clomiphene citrate (clomiphene) administration during the early luteal phase of the menstrual cycle on the luteal function and the pregnancy rate in women, 75 infertile women who ovulated but did not conceive after clomiphene treatment during the early follicular phase and 6 normal cycling women were chosen. Clomiphene was administered orally to 35 of the 75 infertile women at a dose of 50 mg per day for 5 days from the second day of the rise in the basal body temperature (BBT) as well as during the follicular phase, while 40 control patients received clomiphene only during the follicular phase. In the test patients, the rate of pregnancy (25.7%) was significantly (p less than 0.05) higher than that of control patients (10.0%). On the 7th of the rise of BBT, the mean serum progesterone levels of the test patients and normal cycling women treated with clomiphene were significantly (p less than 0.05) higher than those of the control patients. However, the levels of serum estradiol, LH and FSH, the gonadotropin pulsatilities, and the pituitary responses to LH-RH in the test women were not significantly different from those of the control. These data suggest that, when administered during the early luteal phase, clomiphene may act directly on the ovary, enhancing the secretion of progesterone from the corpus luteum, and thereby increasing the rate of pregnancy in infertile women with clomiphene-induced ovulation.

Adult↗
PubMed1987

A new orthodontic force system of magnetic brackets.

Tooth movement in orthodontic treatment is achieved by a combination of mechanical and physiologic forces acting on the teeth and their supporting structures to effect the biologic changes that cause teeth to move through bone. Traditional orthodontic appliances using wires, springs, and elastic forces inevitably cause some degree of discomfort and pain. In the present study, a new magnetized edgewise bracket was designed. The magnet works to move teeth mesiodistally and is not merely a mechanical force. It is well adapted to the biophysical system of tooth and bone interrelationships. Therefore, it works effectively, gives less discomfort, and produces less stress for the patient. The new magnetic appliance provides a force system that approaches the ideal orthodontic requirements.

Adolescent↗