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Biomedical subjects

S Higuchi

Publications and source records attributed to S Higuchi.

At least 433 records · Page 24Linked to original sources

Studies on topical antiinflammatory agents. IV. 21-(Alkylthio)acetates and (methylthio)methoxides of corticosteroids.

A series of 21-(alkylthio)acetates and 21-(methylthio)methoxides of corticosteroids were synthesized and examined for vasoconstrictive activities. The activities of seven compounds were equal to or greater than that of 9 alpha-fluoro-11 beta,21-dihydroxy-16 beta-methyl-17 alpha-valeryloxy-1,4-pregnadiene-3,20-dione (betamethasone 17-valerate, BV). Among them, betamethasone 21-(methylthio)acetate 17-propanoate (2Ca) was found to have the most potent activity, which is superior to that of BV. A structure-activity relationship study revealed that substitution of the 21-hydroxy group of corticosteroids with the (methylthio)acetate function is a useful approach for obtaining potent activity.

Administration, Topical↗

Isolation and purification of a low molecular weight protein from bovine urine.

A low molecular weight protein was separated from urine samples obtained from a heifer with spontaneous renal disease and from cows with CaNa2EDTA-induced renal dysfunction. The molecular weight and electrophoretic mobility of the separated protein were examined. The low molecular weight protein collected by gel filtration chromatography was further separated into two fractions by ion exchange chromatography using DEAE-cellulose. One of the two fractions, the lowest molecular weight protein showed a single band in SDS-PAGE, and its molecular weight was approximately 12,000. An antiserum against this protein formed a single precipitin line with the urine from cows with experimentally induced renal dysfunction and a heifer with spontaneous renal disease by the double immunodiffusion technique. However, the antiserum did not form any precipitin line with the concentrated urine of healthy cow and human beta 2-microglobulin. In cellulose acetate membrane electrophoresis, this protein migrated in the same position as that of serum gamma-globulin from healthy cow.

Animals↗

[Factors of gastric lesions following after transcatheter arterial embolization for primary hepatoma].

To clarify the influence of Transcatheter Arterial Embolization (TAE) on the stomach, endoscopic examination was carried out before and after TAE. Forty-six TAE were performed in 27 patients with primary hepatoma. New gastric lesions, erosions and ulcers, were developed in 25 of 46 TAE. There was no significant relationship between the incidence of the lesions in the cases with esophageal varices (15/24) and the cases without (10/22) and there was no significant relationship between the incidence of the lesions after the first TAE (12/22) and after the second TAE (5/14). Period between the first and the second TAE had no statistical influence on the lesions after the second TAE. Hepatic functions (Child's classification; Rmax, K, R15 of ICG; serum total protein; serum albumin; total bilirubin; prothrombin time; hepaplastin test) before TAE were not statistically related to the appearance of the gastric lesions following TAE (Table 1). On the other hand, the cases which showed apparent effects of TAE including 0.2 time decrease of AFP had the more gastric lesions (P less than 0.05) (Table 2). The cases with upper abdominal pain after TAE had more gastric lesions (24/38) than the cases without (2/8) (P less than 0.05). But the cases undergone TAE with high possibility of the influx of gelatin sponge pieces, lipiodol or anticancer agents into the supplying vessels for the stomach did not exhibit significant incidence of the lesions (Table 3). Thus, when TAE is followed by a 0.2 time decrease in AFP, it is necessary to pay more attention to the gastric lesions. The prophylactic administration of H2 antagonist before or just after TAE did not seem useful to prevent the gastric lesions. These findings suggest that the influx of gelatin sponge pieces, lipiodol or anticancer agents to the stomach does not always cause gastric ulcer or erosion.

Aged↗

[On mechanical behavior of molecular composite resins reinforced with polyaramides. Molecular motion of Oct-PPTA and Ste-PPTA and thermal properties and dynamic viscoelasticity of Oct-PPTA-PMMA and Ste-PPTA-PMMA].

Molecular composites, composed of polymethylmethacrylate (PMMA) resin as matrix reinforced with polyaramides as a rigid core molecule have been developed to produce a denture base polymer with improved dental material properties. N-substituted polyaramides were prepared via metalation using sodium methylsulfinylcarbanion, followed by the reaction with corresponding octyl bromide and/or stearyl bromide in dimethyl sulfoxide. In these molecular composite resins (called Oct-PPTA-PMMA and Ste-PPTA-PMMA short) compounding 3 wt% of N-octylated-PPTA (Oct-PPTA) and/or N-stearylated-PPTA (Ste-PPTA) to PMMA, their dental material properties were in the order of Oct-PPTA-PMMA greater than Ste-PPTA-PMMA greater than or equal to PMMA. Their polymer properties were analyzed to molecular level, using nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric (TG) analysis and dynamic mechanical thermal analysis (DMTA). The molecular motion of the methyl group of Oct-PPTA proved to be constrained for the rigid main chain by T1 (inversion recovery method) NMR spectra in CDCl3 while that of Ste-PPTA was not affected. The thermal properties of the composites were in the order of Oct-PPTA-PMMA greater than Ste-PPTA-PMMA greater than PMMA by TG analysis, and the dynamic storage modulus values were Oct-PPTA-PMMA greater than Ste-PPTA-PMMA greater than PMMA in the region from rubbery state to viscous flow state by DMTA.

Composite Resins↗

Histochemical studies of mitochondrial activities of cultured corneal endothelial cells of cat during wound-healing.

The corneal endothelial cells of the cat were cultured, and in 3 weeks the cells became confluent and formed a cell sheet. The cells were stained with rhodamine 123 and nitroblue tetrazolium (NBT). The frequencies of cells stained by these two methods changed during the 3-week culture, but at the end of the culture the frequencies were stabilized at 58 +/- 3.9 (mean +/- SD) % for the rhodamine 123 staining method and 35 +/- 3.7% for the NBT method. An oval wound of 600 X 400 microns was made in the center of the cultured endothelial cell sheet, and the cell migration was observed by phase contrast microscopy. Six hours after the wounding, the cells began to migrate toward the center of the wounded area, and in 24 hours the denuded area was almost completely covered by migrated cells. In 48 hours the wound was tightly covered by the migrated cells. One hour after the wounding, the cells in the wound margin were strongly stained by rhodamine 123, but not by NBT. The cultured cell sheet was divided into 4 concentric areas, ie, S1 was the center of the wound, S2 was the 100-microns-wide zone inside the original wound edge, S3 was the 100-microns-wide zone outside the original wound edge, and S4 was the 100-microns-wide zone outside the S3 zone. Topographical changes in rhodamine- and NBT-stained cells were observed over a 48-hour period. Rhodamine-positive cells increased in the S1 area, while a decrease occurred in the S2 and S3 areas. NBT-positive cells peaked at 12 hours after the wounding and decreased thereafter. It was concluded that the endothelial cells migrating to cover the wounded area showed a significant enhancement of mitochondrial activity, as indicated by the rhodamine 123 staining, but the succinic dehydrogenase activity revealed by NBT staining was rather suppressed.

Animals↗

[Recovery from cardiac arrest by prostaglandin E1 infusion during emergency open heart surgery].

A 21 day old infant, diagnosed as ASD, VSD, and PDA, was scheduled for an emergency radical operation. After admission, she fell into cardiac failure and was treated with artificial ventilation and infusion of inotropic agents. Anesthesia was induced with fentanyl and maintained with continuous fentanyl infusion and chlorpromazine. Dopamine and dobutamine were administered before she underwent a cor-pulmonary by-pass. At the time of release of aortic clamping, her blood pressure went down and dopamine, dobutamine and isoproterenol were administered. After completion of the cor-pulmonary by-pass, tachy-arrhythmia and hypotension occurred. Digitalis and calcium did not reverse the condition. The thorax was reopened and BP rose. After 15 min, ventricular fibrillation occurred. Defibrillation was carried out, but the heart was arrested. Even with pacing and cardiac massage, cardiac contraction did not resume. However immediately on intravenous administration of PGE1, 40 ng.kg-1.min-1, the heart started to beat. The cause of recovery from cardiac arrest was speculated to be due to reuptake of intracellular Ca2+ by PGE1. We stress therefore, that during and after cor-pulmonary by-pass procedures, PGE1 infusion may be beneficial.

Alprostadil↗

[A case of stunned myocardium determined by nuclear cardiac imaging].

A 75 year old woman with acute chest pain was diagnosed as unstable angina. Anterior akinesis of left ventricule and small anterior perfusion defect were found by 99mTc blood pool imaging and 201Tl myocardial imaging. Coronary arteriography showed no organic stenosis, though anterior akinesis was still continued. Furthermore this akinesis and perfusion defect by 201Tl were all disappeared two weeks later. Thus, we determined this case as a stunned myocardium followed by severe angina with transient coronary obstruction.

Aged↗

[Effects of tachycardia on ischemic canine hearts during nitrous oxide-oxygen-halothane anesthesia].

Effects of tachycardia on left ventricular function, myocardial metabolism and intramyocardial pH under nitrous oxide-oxygen-halothane anesthesia, were studied in 11 canine hearts with critical coronary stenosis. A comparison was made with coronary occlusion. Critical stenosis was produced using a screw occluder to limit the left anterior descending coronary artery blood flow to prevent reactive hyperemia after 10 second occlusion. The degree of ischemia was estimated by intramyocardial pH, arterio-venous lactate and potassium. Intramyocardial pH was measured with a hydrogen ion-selective electrode implanted in the subendocardium. Tachycardia was induced by right cardiac sympathetic nerve stimulation. After 7 min tachycardia in dogs with coronary stenosis, intramyocardial pH decreased significantly from 7.09 +/- 0.10 to 6.83 +/- 0.15, then tended to return toward control levels over a period of 20 min after cessation of tachycardia, although some did not return to the control level even after 30 min. Regarding LV function, LVP and positive LV dp/dt max did not increase. Negative LV dp/dt max decreased significantly. The time constant (T) was prolonged but not significantly, while LVEDP rose considerably from 8.2 +/- 4.1 mmHg to 14.6 +/- 6.8 mmHg. In contrast, after 7 min occlusion, intramyocardial pH decreased significantly from 7.14 +/- 0.08 to 6.72 +/- 0.15 and recovered after 15 min. LVP decreased slightly. Positive and negative LV dp/dt max decreased significantly. T was not prolonged initially, but after reperfusion prolonged significantly. LVEDP increased significantly from 7.9 +/- 3.3 mmHg to 11.9 +/- 6.3 mmHg. In summary, tachycardia in dogs with coronary stenosis under nitrous oxide-oxygen-halothane anesthesia caused regional ischemia. The degree of ischemia was slightly less than with occlusion, but LV diastolic dysfunction was more prominent.

Anesthesia, Inhalation↗

Sensitive determination of ambenonium chloride in serum from patients with myasthenia gravis using ion-exchange resin extraction and reversed-phase ion-pair chromatography.

An effective and selective procedure for the extraction of ambenonium chloride (AMBC) from serum using a weak cation-exchange extraction cartridge has been developed. The solid-phase extraction procedure permitted the extraction of AMBC from serum without adhesion to materials such as the containers. A 200-microliter volume of the eluate could be directly injected on to a reversed-phase ion-pair high-performance liquid chromatographic column. The recovery was in the range 97-100%. The limit of detection for AMBC was 0.5 ng/ml in serum (signal-to-noise ratio = 3). The method was used to determine the serum concentration of AMBC in patients with myasthenia gravis. The method would be useful for monitoring AMBC in serum in order to study its pharmacokinetic behaviour in patients under oral administration therapy.

Adult↗

Oral mucositis and salivary methotrexate concentration in intermediate-dose methotrexate therapy for children with acute lymphoblastic leukemia.

The relationship between salivary methotrexate (MTX) concentration and severity of oral mucositis after administration of MTX was investigated in six children with acute lymphoblastic leukemia. They received two administrations of MTX at 500 mg/m2 with one third given bolusly and the remainder by 24-hour continuous infusion. No significant difference among patients or administration session was observed in serum MTX concentration. Detectable concentrations of salivary MTX (greater than 0.01 microM) were observed during nine of the ten infusions. A concentration of 0.1 microM or more, apparently lasting at least 12 hours, was observed during one infusion and followed by severe mucositis. During two of the ten infusions for different patients, concentrations of 0.04 to 0.07 microM and 0.02 to 0.04 microM, apparently lasting at least 12 and 18 hours, respectively, were observed, followed by moderate mucositis. During the other seven infusions, either much shorter or no increase in salivary MTX concentration was observed, with only mild or no subsequent mucositis. Analysis by Kendall's rank method showed a statistical correlation between concentration at 6 hours of infusion and severity of oral mucositis. The findings suggest that the early secretion of MTX into saliva has a significant role in the development of oral mucositis in leukemic children.

Child↗

Immature alveolar/blood barrier and low disaturated phosphatidylcholine in fetal lung after intrauterine exposure to O,O,S-trimethylphosphorothioate.

Intrauterine exposure to the potent lung toxicant OOS-TMP was found to result in neonatal lethality attributed to immature lungs (Koizumi et al. 1988). The present study was initiated to investigate biological/pathological profiles of such pulmonary immaturity. OOS-TMP was given p.o. to five pregnant female Sprague-Dawley rats on gestation day (G) 19 at 2.5, 7 or 20 mg/kg. Control (N = 6) or pair-fed dams (N = 5: pair-fed to 20 mg/kg dams) received 2 ml/kg corn oil. On G 22, fetuses were delivered by Cesarean section. The biochemical maturity of lungs was assessed by glycogen content and production of disaturated phosphatidylcholine (DSPC), a major component of pulmonary surfactant. Mean DSPC content was significantly lower in fetuses from dams dosed at 7 or 20 mg/kg while mean glycogen concentration, in contrast, was 3- to 6-fold higher in those fetuses than fetuses from control or pair-fed dams. Pathological examination revealed that in fetuses delivered from dams dosed at 7 mg/kg or 20 mg/kg, glycogen-rich cuboidal epithelial cells completely covered the terminal air space and alveolar/blood barriers stayed at the poorly developed stage. The stage of the pulmonary development in those fetuses was similar to those in fetuses on G19. Therefore it was concluded that intrauterine exposure to OOS-TMP delayed pulmonary development, thereby causing respiratory failure after birth.

Animals↗

Population pharmacokinetics of phenytoin from routine clinical data in Japan.

Routine clinical pharmacokinetic data collected from out-patients who received phenytoin were analysed to estimate population pharmacokinetic parameters. There were 505 steady-state phenytoin concentrations and associated dosage rates (mg/day) from 220 out-patients. The data were analysed using NONMEM, a computer program designed for population pharmacokinetic analysis that allows pooling of data from many individuals. The influence of weight on the maximum elimination rate (Vm) and age on the Michaelis-Menten constant (Km) or the influence of dosage form on the bioavailability (F) of phenytoin were investigated. The Vm and Km of a 60-kg adult out-patient were estimated to be 369 mg/day and 3.67 mg/l, respectively. The parameter of a power function of weight was estimated to adjust Vm for body size. The best function adjusts Vm in proportion to weight to the 0.55 power. The Km for patients less than 15 years old was 16% less than that for adults. When the F of phenytoin is assumed to be 100% in the patients prescribed a tablet, the F value in the patients prescribed a powder was 89.5%.

Adolescent↗

The effect of concurrent administration of sodium valproate on serum levels of primidone and its metabolite phenobarbital.

The effect of associated therapy on serum primidone (PRM) and derived phenobarbital (PB) concentrations, and on serum concentrations to PRM dose ratios (L/D ratio) were evaluated retrospectively from 100 consecutive PRM and derived PB determinations in 100 chronically treated epileptic patients. PRM administered was significantly (P less than 0.01) correlated with both serum PRM (r = 0.799 approximately 0.933) and derived PB levels (r = 0.545 approximately 0.870) in patients taking PRM. Derived PB L/D ratios and PB/PRM concentration ratios were higher in patients taking PRM in combination with phenytoin (PHT) and/or sodium valproate (VPA). Therefore, serum levels of PRM and derived PB should be monitored closely in patients taking PRM with PHT and/or VPA.

Adolescent↗

Ethanol patch test--a simple and sensitive method for identifying ALDH phenotype.

The ethanol patch test, which is considered to be a cutaneous model of flushing, was performed on 311 healthy Japanese (237 adults and 74 children). By comparing the results with aldehyde dehydrogenase (ALDH) phenotype determined by isoelectric focusing from hair roots samples, it was demonstrated that the ethanol patch test is a good indicator of the ALDH phenotype. The usefulness of this test in future studies was discussed.

Adult↗

Creutzfeldt-Jakob disease in Japan: an epidemiological study done in a select prefecture between 1976 and 1986.

An epidemiological study was performed with respect to Creutzfeldt-Jakob disease in a designated area in Japan. The subjects were observed in a small rural prefecture where the population generally remains within a limited radius throughout their lives. The patients' life-styles in each area were investigated in detail. Nine cases appeared in 11 years; 6 were definitive and 3 probable. They were all of the subacute type; there were no noteworthy sexual differences, age of onset, course and/or past histories. Three of the nine cases came from two families; the relationship between familial and isolated cases was examined. Revealed facts and time-space clustering were investigated statistically, but no indication of natural transmission was observable.

Aged↗

Clinical utility of a new and simple technique for individualizing phenytoin dosage.

Wagner proposed a new and simple method to predict dosage of drugs obeying simple Michaelis-Menten elimination kinetics. From his theory the following equation, Dn = Do + 1n (Cd/Co)/S can be derived, which forms the basis of predicting the required dosage (Dn) to obtain a desired steady-state concentration (Cd), using initial steady-state concentration (Co), obtained with initial dose (Do) and a population value of S for the drug. We retrospectively investigated the value of S for phenytoin (PHT) in a population of 55 outpatients who had three or more reliable measurements of the steady-state concentration of PHT in serum, measured while they were taking different daily doses. The value of S for PHT was estimated to be 0.0122759 in Japanese patients. The predictive performance of this equation was compared with Bayesian feedback method (B) using retrospective data from 220 outpatients. This equation yielded mean error (ME) of 0.0, mean absolute error (MAE) of 30.7 and root mean squared error (RMSE) of 40.9 mg/d compared to ME of -2.5, MAE of 30.3 and RMSE of 40.1 mg/d for B method. These results indicate that this equation may be a useful adjunct for prediction of PHT dosage as well as B method. Moreover, the simplicity of the equation allows calculation on a hand-held calculator.

Adolescent↗