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Biomedical subjects

K Aisaka

Publications and source records attributed to K Aisaka.

At least 109 records · Page 6Linked to original sources
PubMed1985

The effects of piperidine and its related substances on blood vessels.

Piperidine is an endogenous active amine. Intravenous or intra-arterial administration of piperidine produced vasodilation in anesthetized dogs. The vasodilative effect of piperidine was inhibited by atropine (0.3 mg/kg, i.v.). In the hind limb perfusion experiment in anesthetized dogs, piperidine produced vasodilation, while it showed no vasorelaxing action in various isolated canine arterial strip preparations. These results suggest that the vasodilation caused by piperidine may be produced through activation of muscarinic receptors and that piperidine may act on smaller resistance blood vessels but not on large conductance vessels. In addition, pipecolic acid and N-methyl piperidine, the respective precursor amino acid and metabolite of piperidine, were almost inactive, but nipecotic acid was 1/4 to 1/10 times as active as piperidine as vasodilators. It is suggested that the non-substituted amine moiety of piperidine is very important for the manifestation of vasodilative activity and that piperidine might play a role in regulation of peripheral vascular circulation.

Animals↗
PubMed1985

[Effects of mother-infant interaction on maternal milk secretion and dynamics of maternal serum prolactin levels in puerperium].

Effects of maternal-infant interaction on maternal milk secretion and the dynamics of maternal serum prolactin levels in puerperium were examined in 183 normally delivered mothers without any complications. No significant change was observed in the amount of maternal milk secretion between the primiparas and the multiparas. However, there was a significant increase in the amount of maternal milk secretion in the breast feeding group compared to the supplementary feeding group from the second to the sixth day of the puerperium (p less than 0.005). Moreover, the amount of maternal milk secretion increased significantly in the group that adopted the rooming-in system compared to the non rooming-in group (p less than 0.005). And also the significant increase occurred in the encouragement of breast feeding following the adoption of the rooming-in system (x2 = 7.244, p less than 0.01). There was no significant correlation between the amount of maternal milk secretion and the puerperal maternal prolactin levels, but the maternal serum prolactin level at 24 hours after delivery was significantly higher in the breast feeding group than in the supplementary feeding group (p less than 0.01). Also, the maternal serum prolactin was increased by the stimulation of the baby crying the same as by suckling or manual expression. These facts suggest that the maternal-infant bonding plays the important role in the encouragement of the breast feeding and the maternal serum prolactin may have some actions on the mechanism of maternal milk secretion.

Animals↗
PubMed1985

[Correlation of prolactin-secreting-capacity to circadian profile of prolactin in euprolactinemic women with ovulatory disturbances].

Circadian profile and responsiveness of prolactin to TRH administration were examined in 21 women with ovulatory disturbances. The data were analyzed with reference to the clinical effectiveness of bromocriptine administration. Resting levels of serum prolactin in the patients studied were lower than 25 ng/ml. 14 patients out of 16 cases (Group A) responded to bromocriptine, whose prolactin levels were more than 30 ng/ml during the night in the circadian studies. On the other hand, none of 5 patient (group B) responded to bromocriptine, whose prolactin levels were not more than 30 ng/ml during the night. Group A showed hyper-responsiveness of prolactin to TRH higher than that of Group B. These results suggested that 1) In euprolactinemic ovulatory disturbances there are cases with nocturnal hyperprolactinemia, whose prolactin levels are normal during the day time. These cases will be referred to as occult hyperprolactinemia. 2) Those with occult hyperprolactinemia show increased prolactin-secreting-capacity, which is able to be diagnosed by the hyper-responsiveness of prolactin to TRH administration. 3) The effectiveness of bromocriptine in treating euprolactinemic ovulatory disturbances is due to the suppressive effect of bromocriptine on the hyperprolactinemic states of occult hyperprolactinemia.

Adult↗
PubMed1985

N-(2,6-Dimethylphenyl)-8-pyrrolizidineacetamide hydrochloride hemihydrate (SUN 1165): a new potent and long-acting antiarrhythmic agent.

N-(2,6-Dimethylphenyl)-8-pyrrolizidineacetamide hydrochloride hemihydrate (SUN 1165) at the doses of 2.5 mg/kg i.v. and 3-10 mg/kg i.d. or p.o. restored sinus rhythm from ventricular multifocal arrhythmias induced by two-stage ligation of the coronary artery in the conscious dogs, Harris model, without causing gastrointestinal and central nervous system side effects. The onset of antiarrhythmic action was 1-2 min after i.v. injection and 15-30 min after an oral administration, and this action lasted longer than 1 h after i.v. and 6 h after oral administration, respectively. SUN 1165 was also effective in suppressing ouabain-and halothane-epinephrine-induced ventricular arrhythmias at the doses of 1.7 and 1.2 mg/kg i.v. and 1-10 mg/kg i.d. It did not impair parasympathetic nerve activity. SUN 1165 showed a local anesthetic or membrane stabilizing activity comparable to lidocaine and disopyramide. In conscious dogs without arrhythmia, SUN 1165 had no deleterious cardiohemodynamic effect and no gross behavioral effect at the oral doses of 3 and 10 mg/kg. Thus, it is concluded that SUN 1165 is an orally effective, potent and long-acting class I type antiarrhythmic agent without serious side effects common to other antiarrhythmic drugs.

Anesthetics, Local↗
PubMed1985

[A study on pathogenesis and treatment of normoprolactinemic galactorrhea syndrome].

To investigate the pathogenesis of the normoprolactinemic galactorrhea syndrome, the response of prolactin secretion to TRH administration and the circadian profile of serum prolactin levels were examined in 13 women with galactorrhea whose resting levels of serum prolactin were lower than 25 ng/ml. Bromocriptine (5mg/day) was administered for 30 days and the mid-luteal serum estradiol and progesterone levels, as indicators of luteal function, were also measured before and after the administration. The basal levels of serum prolactin in these patients were significantly higher than those of the control (p less than 0.05), and the response of prolactin secretion also increased significantly at 30, 60, 90 and 120 min. after TRH administration compared to those of the control (p less than 0.005). The circadian profile of serum prolactin showed significantly higher levels from 22 to 8 o'clock compared to the control (p less than 0.05 approximately 0.005). And serum prolactin levels of these patients were higher than 25 ng/ml during the nocturnal period. When bromocriptine was administered, serum prolactin levels of these patients dropped conspicuously, and the nocturnal surges of prolactin also suppressed. Serum estradiol and progesterone levels in the mid-luteal phase normalized apparently due to the administration of bromocriptine (p less than 0.005, p less than 0.005), and galactorrhea also disappeared. These facts suggested that the normoprolactinemic galactorrhea syndrome might be caused by transient occulted hyperprolactinemia, and the treatment with bromocriptine was useful not only in suppressing galactorrhea but also in improving the luteal function in these patients.

Bromocriptine↗
PubMed1985

N-(2,6-dimethylphenyl)-8-pyrrolizidineacetamide hydrochloride hemihydrate (SUN 1165), a new antiarrhythmic agent: effects on cardiac conduction.

Effects of N-(2,6-dimethylphenyl)-8-pyrrolizidineacetamide hydrochloride hemihydrate (SUN 1165) on cardiac conduction were studied in anesthetized, anesthetized open-chest and conscious dogs and rabbit Langendorff hearts following either intravenous (i.v.) bolus injection and continuous infusion or intraarterial injection. SUN 1165 at antiarrhythmic doses (or concentrations), prolonged PQ interval in dogs inherently showing broad QRS complex without affecting QRS duration, but prolonged both PQ interval and QRS duration in dogs showing narrow QRS complex, in a dose-dependent manner. At higher doses (or plasma concentrations), SUN 1165 caused a marked prolongation of PQ interval together with QRS duration and subsequently, in most cases, elicited conduction block within the atrial muscle as evidenced by disappearance of P wave. SUN 1165 caused the dose-related prolongations of atrio-ventricular conduction time and intra-atrial conduction time, and at the highest dose it blocked conduction within the atrial muscle in some cases. In the rabbit Langendorff hearts, SUN 1165 tended to prolong intraatrial and His-Purkinje-ventricular conduction time in preference to atrio-ventricular one. At higher concentrations, SUN 1165 produced conduction block in the Purkinje-ventricular system. These results suggest that SUN 1165, at the antiarrhythmic doses (or plasma concentrations), causes a delay of cardiac conduction by acting on the atrial muscle and His-Purkinje-ventricular system without affecting conduction through A-V node region, and at higher doses (or concentrations) produces conduction block by acting again on the atrial muscle or on His-Purkinje-ventricular system without impairing conduction in the A-V node.

Animals↗
PubMed1984

[The effects of dopamine agonist (bromocriptine) on the secretion of pituitary gonadotropins and ovarian sex steroids in normally cycling women].

To investigate the effects of bromocriptine on the secretion mechanism of pituitary gonadotropins and ovarian sex steroids, 5 mg of bromocriptine was administered to four normally cycling women in the follicular, pre-ovulatory, mid-luteal or menstrual phase, respectively. Blood samplings were taken from two hours before until six hours after the administration every 15 min. by an intravenous indwelling catheter. Serum FSH, LH, prolactin, estradiol and progesterone were determined by RIA, and the changes of basal levels and the pulsatile patterns of these hormones were analysed in each of the four phases. Serum prolactin levels decreased significantly (p less than 0.005) from two hours after the administration of bromocriptine and remained in a very low range in all phases of the cycles until the end of the experiments. The basal levels of FSH showed a significant decrease in the pre-ovulatory and mid-luteal phases two to six hours after the administration (p less than 0.025 approximately p less than 0.005). Also the basal levels of LH showed a significant decrease in the follicular, pre-ovulatory and mid-luteal phases two to six hours after the administration (p less than 0.05 approximately p less than 0.005). However, no significant change was observed in the amplitude or the frequency of the pulsatile patterns of FSH and LH in all phases of the menstrual cycles. The serum levels of estradiol did not show marked changes by the administration of bromocriptine, but the serum levels of progesterone were significantly decreased in the mid-luteal phase two to six hours after the administration (p less than 0.005). These facts suggest that bromocriptine acts mainly on the pituitary rather than the hypothalamus to decrease the serum levels of gonadotropins, and also may have some role in the steroidogenesis of the ovary.

Bromocriptine↗
PubMed1984

Effects of dehydroepiandrosterone-sulphate (DHEA-S) administration on puerperal lactation and maternal prolactin and estradiol levels.

Effects of dehydroepiandrosterone-sulphate (DHEA-S) on puerperal lactation and maternal serum prolactin and estradiol levels were examined in 111 cases of normal vaginal delivery without any complication. The amount of lactation in the DHEA-S administrated group was significantly decreased on the second day of the puerperium (p less than 0.05). No significant difference could be found after the third day of the puerperium, or in the total amount of lactation up to the seventh day of the puerperium. There was also no significant difference in the changes in neonatal body weight. No significant change was observed in maternal serum prolactin levels following DHEA-S administration. But the maternal serum estradiol levels were significantly higher at 0, 6, 12, 24 and 36 hours after delivery following the administration of DHEA-S (p less than 0.05 approximately 0.005). These facts suggested that the transient inhibition of lactation by DHEA-S may be caused by the effect on mammary glands of estrogens which were converted from DHEA-S in the placenta.

Dehydroepiandrosterone↗
PubMed1982

[Effects of prolactin on lipid metabolism (author's transl)].

Effects of prolactin (PRL) on lipid metabolism were examined in the patients with hyperprolactinemia and rabbits. Significant correlation between serum PRL and triglyceride (TG) levels was observed in the patients with hyperprolactinemia (r = 0.417, p less than 0.05). Serum TG levels in non-pregnant adult rabbits were elevated in feeded states by the administration of o-PRL. Marked changes were not observed in the activity of plasma lipoprotein lipase in rabbits by the administration of o-PRL, but in in vitro experiments, the up-take of 14C-acetate into lipid fraction of rabbit liver slice significantly increased by the addition of o-PRL. These findings suggest that PRL activates TG synthesis in liver and consequently increases serum TG levels. The serum levels of TG, free fatty acid, cholesterol and glucose significantly rose in rabbits' fetuses after the administration of o-PRL intraperitoneally. These facts also suggest that the high levels of PRL in maternal and fetal serum and amniotic fluid may have some roles in the growth of the fetus through lipid metabolism.

Adolescent↗
PubMed1981

Purification and properties of lipase from Rhizopus japonicus.

Lipase [EC 3.1.1.3] was purified from the culture supernatant of Rhizopus japonicus KY 521 by ethanol precipitation, chromatography on Column-lite, affinity chromatography on heparin-Sepharose 4B, and separation into two lipases, I and II, by isoelectric focusing. The purified lipases I and II were found to be homogeneous by disc electrophoresis, and showed isoelectric points at pH 7.4 and pH 7.9, respectively. They both had an apparent molecular weight of about 42,000, hydrolyzed tricaprin very rapidly, and exhibited a pH optimum around pH 7.0-8.5. These lipases were inhibited by the addition of serum to the reaction mixtures. These lipases were enhanced slightly in the absence of serum by high concentrations of NaCl and protamine, but were inhibited strongly by these compounds in the presence of serum.

Chemical Phenomena↗
PubMed1981

[Effects of bromocriptine on FSH and LH secretion in women with euprolactinemic anovulation (author's transl)].

A few reports have been given that Bromocriptine effected not only on the hyperprolactinemic anovulations but also on the euprolactinemic anovulations. This study was performed to examine the underlying mechanism, 5 mg of Bromocriptine was daily administered for 30 days to 38 women with euprolactinemic anovulations. The basal secretions of FSH, LH and Prolactin and also the responsiveness to LH-RH, TRH and estradiol were examined. 31.6% of oligomenorrhea, anovulatory cycle and Ist. grade amenorrhea showed ovulatory cycles, however, no ovulations were observed in IInd. grade amenorrhea. The basal levels of FSH and LH significantly increased but the basal levels of Prolactin decreased by Bromocriptine. The responsiveness of FSH to LH-RH was markedly promoted but LH showed no significant change. Serum FSH was suppressed in estrogen loading test after Bromocriptine, which was poorly changed before. On the other hand, serum LH was markedly elevated by estradiol after Bromocriptine, which showed poor elevation before. These results conclude that: 1) Ovulation is induced by Bromocriptine administration in euprolactinemic anovulations. 2) Bromocriptine promotes the FSH and LH secretion from the pituitary and also promotes the reserve of FSH in the pituitary. 3) Bromocriptine promotes the sensitivity of the estrogen feedback in the hypothalamus.

Adolescent↗