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Biomedical subjects

S Murata

Publications and source records attributed to S Murata.

At least 289 records · Page 16Linked to original sources
PubMed1983

[Pharmacokinetics of a new antitumor antibiotic, neothramycin, after intrapleural administration].

In 5 patients with malignant pleural effusion, neothramycin (NTM) was intrapleurally administered at a dose of 30 mg in 3 cases and 40 mg in 2 cases and the pharmacokinetics was studied by using compartment models. The results were as follows: 1) Pleural levels of NTM were described by a mono-exponential equation and the half-life ranged from 3.45 to 6.48 hr. 2) The time to reach the maximum plasma level was 1 to 2 hr after pleural administration. The maximum levels were 54 to 106.4 ng/ml with the 30 mg dosage and 74.7 to 79.2 ng/ml with the 40 mg dosage, followed by a slow decline, with T1/2 ranging from 6.54 to 17.80 hr. 3) The elimination half-life of NTM in the plasma after intrapleural administration was much longer than that after intravenous administration. This phenomenon can be explained by a "flip-flop model": in this case, the rate of transfer from the pleural space to the plasma was much slower than that of the elimination from the plasma. 4) The parameters, K1 and K2, which were obtained by the deconvolution method, seemed to reflect the transfer of NTM between the pleural space and the plasma. 5) In 3 out of the 4 evaluable cases, an extreme decrease in the pleural fluid volume and suppression of reswelling were observed, including a case found to be negative for tumor cells upon cytodiagnosis.

Adenocarcinoma↗
PubMed1982

A study of esterase--its application to biotransformation of midecamycin derivatives.

Esterases of intestinal mucosa and liver from human and rat were used to study the biotransformation of midecamycin derivatives. In the in vitro experiment with rat esterases, the 4"-acyl derivatives were more easily hydrolyzed than the 9-acyl derivatives. Among the 9-acyl esters, the highest hydrolytic activity was observed with butyrate. In the in vivo experiment, when the rats were administered with the derivatives of 4"-depropionylmidecamycin (M1) orally, comparatively more 9-acyl metabolites were excreted in the urine, but the amount of the 4"-acyl metabolites was very small. In the in vitro experiment with human esterases, the 9-acyl esters were hydrolyzed more easily than the 4"-acyl esters. Among the 9-acyl esters of M1, the highest hydrolytic activity was observed with butyrate. When the 9-acyl esters were administered to humans, the n-butyl ester was hydrolyzed faster than the acetyl ester. When the 9,4"-diacetyl ester was administered to humans, comparatively more 4"-acyl metabolites were excreted in the urine. These results suggest that the experiment with the use of these esterases is useful to estimate the biotransformation of midecamycin derivatives.

Animals↗
PubMed1982

Cerebral vasodilation and spasmolytic activity of diltiazem in anesthetized animals.

The effects of diltiazem on the cerebral blood flow and cerebrovascular spasm were studied in pentobarbital anesthetized animals. In Rhesus monkeys, the common carotid and internal carotid blood flow were measured by an electromagnetic flowmeter. Diltiazem (10-300 micrograms/kg, i.v.) dose-dependently increased both the common carotid and internal carotid blood flow, and the increase in internal carotid blood flow persisted for a longer period than that in the common carotid blood flow. In dogs, regional blood flow in the cerebral cortex (rCBF) was measured by means of the hydrogen gas clearance method. Diltiazem (20 micrograms/kg/min, i.v.) increased rCBF by about 20% of the control during the infusion, and the increase in rCBF was still continued 40 min after the infusion was stopped. In cats, the basilar artery was exposed by craniotomy through the transcervico-transclival approach, and vasospasm was induced by topical administration of 5-HT, PGF2 alpha and incubated blood. Diltiazem, either applied topically to the artery (100 micrograms/ml) or infused continuously into the femoral vein (20 or 40 micrograms/kg/min), suppressed the vasoconstriction evoked by the spasmogen.

Administration, Topical↗
PubMed1982

[Tissue distribution of 9, 3"-diacetylmidecamycin in the pregnant rat and in the rat following repeated administration (author's transl)].

The tissue distribution of 9, 3"-diacetylmidecamycin (MOM) was studied in the pregnant rats and in the rats following repeated administration. After oral administration of MOM (200 mg/kg) in the pregnant rats, the levels in the placenta and in the uterus were 2-3 times higher than that in the blood, however the levels in the amniotic fluid and in the fetus were 1/10-1/20 of the blood levels. After the third administration of MOM in the first day (30 mg/kg p.o./dose, 3 times/day, 4-hour interval), the levels in the liver, kidney, lungs, spleen, salivary glands and thymus were 1.5-12 times higher than that in the blood; the level in the muscle was almost equal to that in the blood; and the levels in the brain were 1/3-1/10 of the blood level. The tissue distribution patterns after repeated administrations were found to be similar to those of the first day administrations.

Animals↗
PubMed1982

[Effect of acetyllactoylcholine-1,5-naphthalene disulfonate on the motility of stomach].

The effect of TM-723 on the motility of stomach was investigated by using the electromyogram, extraluminal strain gauge force transducer in dog and by measuring the human gastric emptying time. Three mongrel dogs were equipped with two bipolar electrodes on the serosal surface of the antrum and single bipolar electrode and single strain gauge on the surface of the body. Both the peristaltic spike discharge and contractile activity were recorded during 30 minutes before and 60 minutes after administration of TM-723 1 mg/kg, 3 mg/kg and 5 mg/kg, iv. The peristaltic spikes were suddenly disappeared on administration of TM-723 and after then, recurrent peristaltic spikes were recognized with prolonged interval and increased propagation velocity for about four minutes. The contractile activity increased with the administration of TM-723 for a minute. Gastric emptying time were measured on four healthy men by using of the test meal containing 300 muCi of 99mTc-DTPA before and after administration of TM-723 50 mg per os. The following results were obtained that three of four men had accelerated emptying time and one had no remarkable changes after taking TM-723. These studies suggest that TM-723 activates the motility of the stomach.

Acetylcholine↗
PubMed1982

Familial plasma lecithin: cholesterol acyltransferase deficiency. A new family with partial LCAT activity.

A 43-year-old woman and her 47-year-old brother were studied because of corneal opacity. They showed a marked decrease in plasma high density lipoproteins (HDL) and a decrease in the ester ratio of plasma total cholesterol. Discoidal particles were found in the HDL2 fraction (d 1.063-1.125). A marked heterogeneity of low density lipoproteins was disclosed in both patients by electron microscopy. Apoprotein analysis revealed an increase in apo E and a decrease in apo A-I and A-II in both patients. These abnormalities were similar to the data reported in other cases with hereditary lecithin : cholesterol acyltransferase (LCAT) deficiency. However, several interesting dissimilarities have been disclosed as compared with the previously reported cases. Neither patient had proteinuria, and their kidney functions were within the normal limits. The ester ratios of plasma cholesterol of both patients were the highest among the cases reported thus far. Their plasma LCAT activities were 14.4 and 15% of the normal mean values determined by Glomset-Wright's common-substrate method. The enzyme activities determined by Stokke-Norum's self-substrate method were 40.2 and 29% respectively. These results may indicate that this inherited disorder is not characterized by absence of plasma LCAT or presence of inhibitory factors in plasma, but by the presence of partially inactive LCAT in patients' plasma.

Adolescent↗
PubMed1982

[Change of pattern of gastric emptying after selective proximal vagotomy].

The patterns of gastric emptying after selective proximal vagotomy (SPV) and SPV with pyloroplasty (SPV + D) were studed using a liquid labelled with 99mTc-DTPA. By means of on-line computer facility, it was possible to analyse the relative role of the Whole stomach and the antrum within the overall frame work of gastric emptying. In the time/activity curve of the whole stomach, all of 3 groups emptied in exponential curve. Comparing with normal subjects, SPV subjects were tending to empty slowly, while SPV + D subjects were tending to empty rapidly. In the time/activity curve of the antrum, normal and SPV + D subjects had two types of emptying--one was represented in the decreasing curve and another was represented in the increasing-decreasing curve. While SPV subjects had only one type of emptying which was represented in the increasing-decreasing curve. From a consideration of the pattern of gastric emptying curve, SPV subjects had two different emptying states compared with normal subjects--one was the delay of entering the antrum from the fundic side of stomach, and the other was that effective antral emptying did not readily start. While SPV + D kept more neally normal gastric emptying that it of SPV.

Adult↗
PubMed1981

Acute toxicity and pharmacokinetics of dibekacin mice.

The LD50 values of dibekacin to mice were determined following three different methods of administration, namely, intravenous constant infusion, intravenous bolus injection, and intramuscular injection. The serum levels of dibekacin were pharmacokinetically analyzed. The differences in LD50 values between the methods of administration were discussed from the viewpoints of pharmacokinetics. 1) The LD50 value following the intravenous constant infusion was higher than that following the intravenous bolus injection and approached the level of that following the intramuscular injection, when the infusion rate of the drug was decreased by increasing the infusion period. 2) The biological half-life of dibekacin in mice was 24--45 min. 3) The volume of distribution increased as its dose increased, and a linear correlation was noted between log Vd and log (dose). 4) The difference among the maximum serum concentrations calculated with dibekacin following the administration of LD50 was small, which coincided with the results of the experiment that the serum concentrations of dibekacin at the death following the administration of LD100 were almost the same regardless of the method of administration.

Animals↗
PubMed1981

Pharmacokinetics of dibekacin in rabbits and dogs.

The behaviors of dibekacin after three administration methods to rabbits and dogs were pharmacokinetically analysed. 1) In both rabbits and dogs, the pharmacokinetic constants for the intravenous constant infusion and intramuscular injection were similar to each other, and the serum levels after the intravenous constant infusion for 1 hr were similar to those after the intramuscular injection except the peak time. 2) In both rabbits and dogs, Vd increased with the dose and a linear correlation was noted between log Vd and log (dose). 3) The tissue concentrations of dibekacin decreased with the decrease in the serum concentration. 4) A correlation equation, log T 1/2 = 0.194 . log B + 1.128, was obtained, where T 1/2 and B represent the biological half-life of dibekacin and the body weight of animals, respectively. It was suggested that the pharmacokinetic behaviors of dibekacin in human beings can be predicted from the results of the animal experiments.

Animals↗