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Biomedical subjects

N Awata

Publications and source records attributed to N Awata.

At least 55 records · Page 3Linked to original sources
PubMed1985

[Metabolism of lenampicillin hydrochloride. I. Metabolism of ampicillin structure].

Metabolism of lenampicillin hydrochloride (LAPC), especially ampicillin (ABPC) structure of LAPC, was investigated after oral administration in human, dogs and rats. The unchanged compound was not detected in blood and urine, furthermore in animal portal vein after oral administration of LAPC in human and 2 animals. Therefore, LAPC seemed to be rapidly hydrolyzed during the process of absorption. The intestinal absorption of LAPC was satisfactory in view of the urinary excretion of metabolites, accounting for 93% of dose in human, 74% in dogs and 55% in rats, respectively. It could be judged by the bioautograms and the correlation between bioassay and HPLC determination of ABPC that the active metabolite in blood or urine was only ABPC. The major urinary metabolites were ABPC, alpha-aminobenzylpenicilloic acid (ABPA) and 5S-penicilloic acid isomer (5S-ABPA) in human and 2 animals, but the differences were observed on the excretion ratio between human, dogs and rats. LAPC was stable in the intestinal contents, but liable to hydrolyze in the intestinal wall, blood and liver of rats. From the facts described above, it was concluded that LAPC was the efficient prodrug of ABPC in terms of the enhancement of absorption and decrease of side effects.

Administration, Oral↗
PubMed1985

[Metabolism of lenampicillin hydrochloride. II. Metabolism of promoiety].

The in vitro and in vivo metabolism of promoiety in lenampicillin hydrochloride (LAPC) were investigated in rats and dogs. After incubation of LAPC with intestinal or liver preparations and blood of rat, diacetyl, acetoin and 2,3-butanediol were identified as metabolites of LAPC. The main metabolite in peripheral plasma was 2,3-butanediol after oral administration of LAPC in rats and dogs. On the other hand, high levels of acetoin were found out in portal plasma for early period after dosing of LAPC. These results suggested that the biotransformation of promoiety in LAPC to acetoin carried out mainly in intestinal tissues, but acetoin was converted to 2,3-butanediol in liver. Acetoin and 2,3-butanediol were also excreted in urine, but their urinary excretion were very low, and the combined excretion were accounting for about 9% of dose up to 48 hours after dosing in rats and less than 1% in dogs, respectively. The major metabolic pathways of promoiety in LAPC were postulated as below. (Formula: see text).

Acetoin↗
PubMed1985

[A case of multiple cerebral aneurysms caused by cardiac myxoma].

A case of neoplastic aneurysm caused by left atrial myxoma is reported. The patient was a 50-year-old woman who has been suffered from occasional vertigo and syncopal attack. She was admitted with a sudden loss of consciousness and cerebellar ataxia on December 1, 1983. Cerebral angiogram revealed multiple aneurysms in the periphery of both middle cerebral arteries and obstruction of the right superior cerebellar artery. Echocardiography displayed a cardiac myxoma in the left atrium. She suddenly died from recurrent cerebral embolism on January 7, 1984. The diagnosis was confirmed by the autopsy. The histopathological examination revealed that the wall of cerebral arteries were destroyed by the tumor cells of myxoma, and it caused cerebral aneurysms. We presented the detail of this case, and discussed about a mechanism and a treatment of neoplastic aneurysms.

Female↗
PubMed1984

Enhanced suppression of myocardial slow action potentials during hypoxia by free fatty acids.

Effects of free fatty acids (palmitate and linoleate) on myocardial contractility and slow action potentials (APs) were examined in Langendorff-perfused chick hearts. To study the slow APs exclusively, the fast Na+ channels were voltage-inactivated in elevated K+ (25 mM), and the concentration of Ca2+ ion was increased to 5.4 mM in order to induce slow APs. Palmitate (0.18, 0.54 or 0.72 mM) along with albumin (0.12 mM) was added to the perfusate. Albumin by itself did not affect contractility or the slow APs during normoxia and hypoxia. Under well oxygenated conditions, palmitate had no effect on contractility or the slow APs. However, palmitate accelerated the decline of contractility during hypoxia in a dose-dependent fashion. Hypoxia suppressed the slow APs, and palmitate and linoleate further exacerbated the suppression of slow APs produced by hypoxia. Nevertheless, palmitate and linoleate did not enhance the hypoxic reduction of the tissue high energy phosphate level. The present results suggest that free fatty acids elicit cardio-depressant effects on hearts through their direct action on the myocardial cell membrane (slow channels) rather than through any metabolic effects.

Adenosine Triphosphate↗
PubMed1984

Beneficial effect of taurine on congestive heart failure induced by chronic aortic regurgitation in rabbits.

Taurine (2-aminoethanesulfonic acid) is known to have a cardiotonic action. The present study was designed to see whether oral treatment with taurine could improve the status of congestive heart failure induced by aortic regurgitation. Nine rabbits were treated daily with taurine (100 mg/kg) after producing aortic regurgitation. Cumulative mortality at 8 weeks in the non-treated group was 52% compared with 11% in the taurine-treated group (p less than 0.05). Cardiac function (max dP/dt) was significantly decreased in rabbits with aortic regurgitation, whereas in taurine-treated rabbits, cardiac function was maintained the same as control. The present data suggest that taurine prevented the rapid progress of heart failure, and consequently prolonged the life expectancy.

Animals↗
PubMed1983

[Synthesis of (3-2H)-and (3-3H)-cianidanol].

In order to study the metabolism of cianidanol (I), [3-2H]-(I) and [3-3H]-(I) were synthesized. (I) was benzylated and then oxidized with DMSO-Ac2O to give 2R-3',4'5,7-tetrabenzyl-cianidan-3-one (III). (III) was reduced with NaB2H4 or NaB3H4, and then debenzylated to give [3-2H]-(I) or [3-3H]-(I). [3-2H]-(I) was obtained with the over all yield of 21% from NaB2H4. In the other hand, [3-3H]-(I) was obtained with the over all yield of 23% from NaB3H4.

Benzopyrans↗
PubMed1983

Therapy of congestive heart failure with orally administered taurine.

The clinical efficacy of 2 gm BID of oral taurine (2-aminoethane sulfonic acid) was studied in 24 patients with congestive heart failure (CHF). We expressed the severity of CHF by a score based on clinical signs and symptoms and on roentgenographic data. The maximum possible score, corresponding to the worst CHF, was 23 points. How much the 24 patients improved after receiving taurine for four or eight weeks was estimated by the difference between their pretreatment and posttreatment scores. In 19 of the 24 patients, taurine was effective. In the group as a whole, mean (+/- SEM) scores fell significantly, from 7.3 +/- 0.6 before treatment to 4.4 +/- 0.5 after treatment. Thirteen of the 15 patients who were designated as New York Heart Association (NYHA) functional class III or IV before receiving taurine could be designated as class II after they completed the study. This pilot study should prompt further investigation into the possible use of taurine in the treatment of patients with CHF.

Administration, Oral↗