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Biomedical subjects

Y Takiguchi

Publications and source records attributed to Y Takiguchi.

At least 127 records · Page 7Linked to original sources
PubMed1987

Reciprocal potentiation of a vasoconstrictor response between 5-hydroxytryptamine and clonidine in the perfused mesenteric vascular bed of the rat.

The interaction between 5-hydroxytryptamine (5-HT) and clonidine, an alpha 2-adrenoceptor agonist, was investigated in the isolated perfused mesenteric vascular bed of the rat. Clonidine itself did not cause vasoconstriction even at 300 micrograms. However, clonidine in the presence of 5-HT (10 and 100 nM) caused a marked vasoconstriction in a dose range of 0.1 micrograms to 300 micrograms. Prazosin inhibited the clonidine response, whereas yohimbine did not. The potency of prazosin against clonidine was less than that against an alpha 1-adrenoceptor agonist phenylephrine. Therefore, it is suggested that clonidine activated alpha 1-like adrenoceptors. 5-HT also potentiated the vasoconstrictor response to perivascular nerve stimulation, exogenous norepinephrine (NE) and phenylephrine. Calcium entry blockade by nicardipine (0.1 microM) reduced the response to clonidine in the presence of 5-HT, whereas that to phenylephrine in the presence or absence of 5-HT was not reduced. On the other hand, clonidine (0.01-1 microM) potentiated the vasoconstrictor effect of 5-HT more than NE did. Ouabain (1 microgram/ml) enabled clonidine to exhibit an agonistic action, and also enhanced the contractile response to 5-HT. In conclusion, 5-HT modulated the vasoconstrictor effect of clonidine, and the vasoconstriction with 5-HT was also facilitated by clonidine reciprocally. It is possible that a partial depolarization of the cell membrane is the common mechanism for their reciprocal potentiation.

Animals↗
PubMed1986

[Mitotic activity of cancer cells and survival of gastric cancer patients].

An in vivo stathmokinetic method was used to analyze the mitotic activity of cancer cells from 43 gastric cancer patients. The mitotic activity was distributed between mitotic index (MI) 40.0% and MI 127.0%. The patients were classified into 3 groups; low mitotic activity (L-MA) group (MI less than 70.0%), middle mitotic activity (M-MA) group (70.0%) less than or equal to MI) 90% and high mitotic activity (H-HA) group (MI greater than 90.0%). Survival curve and average survival period were examined and compared with each of 3 mitotic activity groups. The survival curve of L-MA group was better than that of M-MA group (generalized Wilcoxon test, Z = 1.815, p less than 0.1), and the latter was significantly better than that that of H-MA group (generalized Wilcoxon test, z = 2.048, p less than 0.05). Average survival period (mean +/- S.D.) of dead patients from cancer recurrence was 24.0 months in L-MA group (n = 1), 16.1 +/- 2.4 months in M-MA group (n = 9) and 7.4 +/- 2.4 months in H-HA group (n-13). Patients with gastric cancer of high mitotic activity died earlier than patients with that of low mitotic activity in the identical histologic type, identical degree of cancer invasion and the identical stage of cancer. The results suggested that the mitotic activity of cancer cells was utilized as a new prognostic parameter of gastric cancer.

Adenocarcinoma, Mucinous↗
PubMed1986

[A phase I study on intravenous drip infusion of astromicin].

A phase I study on intravenous drip infusion of astromicin (ASTM, KW-1070), an aminoglycoside antibiotic, was performed on 9 healthy adult male volunteers to investigate the safety and pharmacokinetics of this drug. ASTM 200 mg was dissolved in 250 ml of saline and given to each of 6 volunteers by drip infusion in 1 hour. For comparison, 200 mg of ASTM in 1 ml of saline was injected intramuscularly. No subjective and objective reactions were found, and laboratory test value did not show any change possibly caused by ASTM. In a single administration study, Cmax was 10.8 micrograms/ml by intramuscular injection and 12.0 micrograms/ml by intravenous drip infusion. The areas under the time-serum concentration curve were 35.6 micrograms X hr/ml and 34.9 micrograms X hr/ml, respectively; that is, the serum levels of ASTM after one-hour intravenous drip infusion changed almost identically to those after intramuscular injection. In a multiple administration study, the change in serum levels of ASTM after the ninth administration was approximately the same as that after the first one. This means that no accumulation of ASTM in serum occurred. Recovery rates of ASTM in urine up to 8 hours after a single intramuscular injection and a single intravenous drip infusion were 85.4% and 87.5%, respectively. These results also support the conclusion that there is no accumulation of ASTM in the body by repeated administrations.

Adult↗
PubMed1985

Effect of ophthalmic administration of S-596 (Arotinolol) on intraocular pressure and haemodynamics in health volunteers: comparison with timolol.

The effects on intraocular pressure (IOP) and haemodynamics of two beta-blockers, arotinolol and timolol, administered topically to the eye, were studied in 6 healthy volunteers in a cross-over trial. 0.5% timolol or 0.5% arotinolol ophthalmic solutions drop was instilled in both eyes of the volunteers at an interval of 48 hours. Timolol lowered IOP by about 31.9% 1 hour after administration and the effect continued until 3 h, whilst arotinolol lowered it significantly 2 h after instillation and the same maximum effect as that of timolol was obtained after 3 h. Arotinolol was detected in blood in all subject and timolol in blood in one subject, although it was found in all subjects in urine. Both drugs lowered heart rate at rest and attenuated the increase in the double product (products of blood pressure and heart rate) at exercise. The effect of timolol on the double products was larger. Thus, arotinolol and timolol decreased IOP to similar extent, although the maximal effect of arotinolol was delayed. Arotinolol as well as timolol affected haemodynamics through absorption into circulation, but the former had less effect on haemodynamics during exercise.

Adult↗
PubMed1985

Anti-arrhythmic effect of nadolol in experimental arrhythmias: comparison with propranolol and alprenolol.

The effects of nadolol on experimental arrhythmias were investigated and compared with those of propranolol and alprenolol. The arrhythmias were induced by either ouabain, holothane plus adrenaline or acute coronary occlusion in anesthetized dogs. All three beta-blocking drugs in a dose range of 10 to 200 micrograms/kg inhibited halothane plus adrenaline-induced arrhythmias. These drugs also attenuated coronary occlusion-induced ventricular arrhythmias as well as other electrical abnormalities such as electrical alternation and conduction delay. Among the three drugs, nadolol was the most potent in suppressing both types of arrhythmias. Contrary to the potent effects on these arrhythmias, nadolol was ineffective against ouabain-induced arrhythmias even in a dose of 3 mg kg, while propranolol and alprenolol were significantly effective in a dose of 100 micrograms/kg. It is probable that the anti-arrhythmic effect of nadolol is exclusively due to its beta-blocking activity.

Alprenolol↗
PubMed1984

Extrinsic innervation of the canine superior vena cava, pulmonary, portal and renal veins.

The responses of the superior vena cava, portal, pulmonary, and renal veins to electrical stimulation of sympathetic nerves were investigated in dog. The vascular response was measured by the method with an intravascular cuff. The contractile responses to neural stimuli were mediated mainly by adrenergic mechanism in the four veins and that of the portal vein was, in addition, mediated in part by cholinergic one. The latter mechanism was also found in some cases of the pulmonary vein. As for the superior vena cava and the left renal vein the right-side dominancy in innervation was observed. These observations suggest a possible correlation between the embryogenesis of vein and its innervation.

Animals↗
PubMed1984

Hemodynamic effects of arotinolol in anesthetized dogs and its affinities for adrenoceptors in vitro.

Hemodynamic actions of arotinolol in anesthetized dogs and its effects on alpha- and beta-adrenoceptors were examined. Arotinolol produced dose-dependent decrease in mean blood pressure, heart rate, cardiac output, maximum rate of left ventricular pressure rise and coronary blood flow in a dose range of 1 microgram/kg-3 mg/kg. Total peripheral resistance (TPR) increased with arotinolol dose-dependently in a dose range of 1 microgram/kg-0.3 mg/kg, but at doses of 1 and 3 mg/kg the increase in TPR was less. Arotinolol at a dose of 10 micrograms/kg significantly inhibited the blood pressure and heart rate responses to isoproterenol. Propranolol at the same dose produced only a slight inhibition of these. Arotinolol at a dose of 3 mg/kg attenuated the pressor response to phenylephrine without any effect on the response to angiotensin-II in anesthetized dogs. Propranolol at the same dose produced only a slight inhibition of the response to phenylephrine. In the study of radioactive ligand binding assays, arotinolol showed high affinities for both beta 1- and beta 2-adrenoceptors. Arotinolol showed an affinity also for alpha 1-adrenoceptors which was comparable to the affinity of yohimbine. Thus, the present results support the idea that arotinolol possesses both alpha- and beta-adrenoceptors blocking effects.

Adrenergic beta-Antagonists↗
PubMed1984

[A clinicopathological study on hematogenous recurrence of colo-rectal cancer--with special reference to prediction and prevention of the recurrence].

Hematogenous recurrence was investigated in 325 cases of colo-rectal cancer. Hematogenous recurrence was confirmed in 34 cases including 25 liver, 5 lung, 2 bone, one brain and one skin recurrence. Most of the cases (28 cases, 82.4%) revealed a single or multiple hematogenous recurrences without showing additional other types of recurrence. Histological examination of cancer lesions indicated that patients with the findings consisting of moderate and/or high grade of vein invasion (v2-3), subserosal and extramural vein invasion with node metastasis showed high recurrent rate. One and two year survival rate of the patients treated with MF-MF' adjuvant chemotherapy was greater those the patients with F-F' chemotherapy or those without chemotherapy. However, 3-, 4- and 5- year survival rate did not show significant difference among 3 therapeutic groups. The analysis of survival curves also indicated no significant difference among 3 therapeutic groups. These results may suggest that hematogenous recurrence is derived from pre- and/or intra-operative micrometastasis or transplantation of cancer cells, that patients with the above mentioned histological evidence must be clinically treated as a high risk group for recurrence and that MF-MF' adjuvant chemotherapy can be effective in lowering the recurrence rate during the first one or two years after operation.

Antineoplastic Agents↗
PubMed1984

[A case of ovarian carcinoma preceded by intracranial metastasis].

A 28-year-old woman with primary ovarian carcinoma which was found with intracranial metastasis is reported. The patient was operated on because of metastatic brain tumor with unknown primary lesion. Subsequently, left ovarian tumor was found, and left salpingo-oophorectomy was performed. The histological diagnosis was endometrioid carcinoma. A review of the literature shows that intracranial metastasis by ovarian carcinoma is very rare. The incidence is lower than 2.1%. The present case in which intracranial metastasis manifested itself before primary ovarian carcinoma seems to be extremely rare.

Adenocarcinoma↗
PubMed1984

Phase I study of 2,4-diamino-6-(2,5-dichlorophenyl)-s-triazine maleate (MN-1695), a new anti-ulcer agent.

A phase I study of 2,4-diamino-6-(2,5-dichlorophenyl)-s-triazine (MN-1695), which is expected to have an anti-ulcer effect, was performed in 14 healthy male subjects. The safety and pharmacokinetics were examined in single-dose oral administration of 1, 2, 4, 8 and 16 mg/body and multiple-dose administration of 2 mg/body/day, once daily, for 28 consecutive days. As for the subjective symptoms, only light headache, general malaise and heart burn were observed in two out of 4 subjects in the 16-mg group. No abnormalities were found in blood pressure, pulse rate, respiratory rate, body temperature, body weight and ECG both in single- and multiple-dose studies. No abnormal changes attributed to this drug appeared in hematological and biochemical examinations and urinalysis. Times for reaching the maximum plasma concentration in the single-dose study were 3.5, 8 and 3.3 h in 4-, 8- and 16-mg groups, respectively. The elimination half-lives from the plasma were 152, 145 and 148 h for the 3 groups, respectively. The plasma concentration curves in the multiple-dose study were similar to those simulated with the pharmacokinetic parameters obtained in the single-dose study. The plasma concentration increased until the 14th day, as the administration continued, and reached steady state thereafter; there seemed to be no abnormal cumulation. The elimination patterns after multiple-dose administration were almost the same as those in the single-dose study; the half-life was about 170 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[A clinicopathological study on carcinoma of the gastric stump, with special reference to mucosal change].

Ten carcinomas of the gastric stump reconstructed by Billroth I (one case) and Billroth II (9 cases) methods were treated an average of 20 (range: 7-46) years after partial gastrectomy. Because of highly advanced carcinoma, total gastrectomy with resection of invaded organs was performed. The 5-year survival rate was 33%, and was not different from that in patients with carcinoma of the cardia. Thus, the prognosis of gastric stump carcinoma was not poor if extended radical operation was carried out. The mucosa showed severe atrophic gastritis with intestinal metaplasia or atrophic and hypertrophic gastritis in patients with carcinoma. However, the mucosa was hyperplasia of the glands in almost all patients with stomal ulcer. Thus, our findings suggest that atrophic change with intestinalization plays a role in gastric carcinogenesis.

Adenocarcinoma↗
PubMed1983

Terminal steps in the biosynthesis of herbicidins, nucleoside antibiotics.

The biosynthetic relationship of the herbicidins produced by Streptomyces saganonensis was studied with blocked mutants by means of a bioconversion method using growing and resting cells. It is proposed that the biosynthetic sequence for herbicidins is; herbicidin G----herbicidin F----herbicidin A. Both herbicidins A and F were converted to herbicidin B by non-enzymatic reactions. Herbicidin G was also converted to herbicidin C non-enzymatically.

Anti-Bacterial Agents↗
PubMed1983

Milbemycins, a new family of macrolide antibiotics. Fermentation, isolation and physico-chemical properties of milbemycins D, E, F, G, and H.

Strain Au-3, a mutant of Streptomyces hygroscopicus subsp. aureolacrimosus, obtained with ultraviolet irradiation, was a high-yield strain of milbemycins D, E, F, G and H. Fermentation studies on the strains were conducted in shake flasks and 30-liter jar fermentors. Isolation of the metabolites was performed by adsorption on resinous adsorbent followed by elution with aqueous MeOH and separated by silica gel column chromatography. Milbemycin D was obtained as colorless needles after recrystallization and milbemycins E, F, G and H were purified to homogeneity by column chromatography. Physico-chemical characterization revealed that milbemycins D, E, F, G and H were new antibiotics possessing the 16-membered macrocyclic lactone with a 6,6-membered spiroketal ring system.

Anti-Bacterial Agents↗