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Biomedical subjects

T Irie

Publications and source records attributed to T Irie.

At least 181 records · Page 10Linked to original sources
PubMed1991

[Kinetics of the falling of airborne mite allergens (Der I and Der II)].

A futon (Japanese quilt) was beaten to disperse mite allergens into the air in a closed room, and the airborne allergens were collected both by Andersen air sampler for particle size analysis and by slit air sampler for kinetic analysis of the clearing of the allergens from the air. After extraction of the allergens from the agar plates in the samplers, two kinds of major mite allergens (Der I and Der II) were immunochemically quantitated. We found that the aerodynamic diameters of both allergens were mainly above 5.5 microns, and that airborne allergen levels decreased to about 10% of the starting level in 30 minutes, indicating the rapidity of the falling of both allergens.

Air Pollutants↗
PubMed1991

[Evaluation of different treatments of Japanese bed quilts for reducing mite allergens].

We evaluated the effectiveness of different treatments of Japanese bedquilt (futon) in reducing mite allergens: vacuum-cleaning, beating plus vacuum-cleaning and washing of the whole futon in water. Before and after these treatments, small amounts of cotton were taken out of the futon and mite allergens were extracted from the cotton into water. The absolute contents of two kinds of major allergens of two Dermatophagoides species were immunochemically quantitated. We found that beating and vacuum-cleaning reduced the allergen contents by only about 40%, whereas washing reduced the allergens by more than 90%. Therefore, for reducing airborne mite allergens generated from futon, we think that washing the whole futon in water is the most effective method.

Allergens↗
PubMed1990

Exercise-induced silent myocardial ischemia in patients with vasospastic angina.

UNLABELLED: To clarify the incidence and clinical characteristics of exercise-induced myocardial ischemia in patients with vasospastic angina, we performed exercise thallium computed tomography in 25 patients who had no significant coronary artery stenosis greater than 70%. Coronary artery spasm was documented by coronary angiography in all patients. Eleven patients (44%) developed exercise-induced perfusion defects, but only four of them had anginal pain (36%). Diltiazem (90 mg, administered orally) prevented the development of exercise-induced perfusion defects in all patients. Multivessel coronary spasm was documented by coronary angiography in 11 patients, and nine of them (82%) showed exercise-induced perfusion defects (p less than 0.05). CONCLUSION: (1) Exercise-induced myocardial ischemia was demonstrated in 44% of patients who had vasospastic angina without fixed coronary stenosis, and 64% of them were asymptomatic. (2) Patients with multivessel spasm had a greater prevalence of exercise-induced myocardial ischemia than those with single-vessel spasm.

Angina Pectoris, Variant↗
PubMed1990

Enhancement of the antiinflammatory effect of ethyl 4-biphenylyl acetate in ointment by beta-cyclodextrin derivatives: increased absorption and localized activation of the prodrug in rats.

Ethyl 4-biphenylyl acetate (EBA) is a prodrug of the antiinflammatory 4-biphenylyl acetic acid (BPAA). The inclusion complexes of EBA with beta-cyclodextrin (beta-CyD), heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD), and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) at a molar ratio of 1:2 (EBA:cyclodextrin) were prepared and used to make hydrophilic antiinflammatory ointments. The in vitro release of EBA from the ointments was enhanced by complexation in the order of beta-CyD less than DM-beta-CyD less than or equal to HP-beta-CyD. The improvement correlated with the improved solubility and not with the decreased diffusibility observed to occur upon the complexation of EBA. In vivo the complexation with cyclodextrin derivatives increased both the release of EBA from the vehicle and its conversion in the underlying tissue to BPAA, but the total of EBA and BPAA in the tissue was decreased. In vitro studies confirmed that the effects of cyclodextrin derivatives on the conversion were exerted indirectly. The combination of the enhanced release and of the enhanced prodrug hydrolysis by esterases in the site where the antiinflammatory action is required resulted in increased therapeutic effects. In the model of carrageenan-induced acute edema in rat paw, the complexation improved the therapeutic effects over those of EBA alone in the order of beta-CyD less than DM-beta-CyD less than HP-beta-CyD. HP-beta-CyD may be a particularly useful cyclodextrin derivative since it improves the topical availability and does not irritate tissues.

Animals↗
PubMed1990

Hepatic inferior vena cava obstruction: treatment of two types with Gianturco expandable metallic stents.

Gianturco expandable metallic stents were used for treating six patients with inferior vena cava (IVC) obstruction due to compression by large hepatic tumors and three patients with idiopathic obstruction of the hepatic IVC and Budd-Chiari syndrome who showed reocclusion or stenosis 3-21 months after previously performed percutaneous transluminal angioplasty (PTA). In all six patients with compression by hepatic tumors, stents dilated the IVC and debilitating edema of the lower body disappeared. In the three patients with idiopathic obstruction, stents were placed after repeat dilation of the lesions and Budd-Chiari syndrome did not recur during a follow-up period of 7-10 months. In two of the three, cavograms obtained 8 months after placement showed the channels to be open with minimal intimal thickening. Gianturco expandable metallic stents can correct IVC obstruction due to compression by hepatic tumors and are useful in preventing reocclusion of the IVC after PTA for the treatment of idiopathic obstruction. The authors recommend using tanem stents connected by at least two struts.

Aged↗
PubMed1990

Utility of 2-hydroxypropyl-beta-cyclodextrin in an intramuscular injectable preparation of nimodipine.

Possible utility of hydroxyalkylated beta-cyclodextrin (beta-CyD) derivatives as parenteral drug carriers was investigated, using nimodipine, a dihydropyridine derivative with calcium antagonistic action, as a model drug. The aqueous solubility of nimodipine increased linearly with increase in the concentration of hydroxyalkylated beta-CyDs, showing an AL-type phase solubility diagram. The stability constant of nimodipine--hydroxyalkylated beta-CyD complexes was in the order of 2,3-dihydroxypropyl-beta-CyD less than beta-CyD less than 2-hydroxyethyl-beta-CyD less than 3-hydroxypropyl-beta-CyD less than 2-hydroxypropyl-beta-CyD, and the solubilizing ability of the beta-CyDs was also in that order. The results of powder X-ray diffractometry and thermal analysis suggested 1:3 (guest:host) complex formation of nimodipine with 2-hydroxypropyl-beta-CyD in the solid state. The dissolution rate of nimodipine-2-hydroxypropyl-beta-CyD complex was much faster than that of the drug alone. Nimodipine-2-hydroxypropyl-beta-CyD complex gave higher plasma levels of the drug after intramuscular administration to rabbits, i.e., the area under the plasma concentration--time curve and the maximum plasma concentration of the complex were about 2.5 times higher than those of the drug alone. The muscular damage after the injection of nimodipine was reduced by the administration of the complexed form.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1990

Pharmacological and biochemical assessment of SM-10888, a novel cholinesterase inhibitor.

The effects of the compound SM-10888 (9-amino-8-fluoro-1,2,3,4-tetrahydro-2,4-methanoacridine citrate) in a number of pharmacological and biochemical tests were studied and compared to those of tacrine (THA), amiridin, HP-029 and physostigmine. SM-10888 inhibited cholinesterase activity (IC50: 2.3 x 10(-7) M) in rat cortical P2 fraction with almost the same potency as THA, while SM-10888 was 2-4 times more potent than amiridin and HP-029, but about 10 times less potent than physostigmine. When given to mice p.o., SM-10888 induced central (hypothermia) and peripheral (salivation) cholinergic effects. When the ratio of the ED50 value for hypothermia to that for salivation was regarded as the index of the selectivity to the central nervous system (CNS), SM-10888 was shown to be about 3 times more selective to the CNS than the other four drugs in mice. The minimum effective dose of SM-10888 for its increasing effect on acetylcholine (ACh) content in the mouse cerebral cortex was about 10 times higher than that of physostigmine, but 5-10 times lower than those of THA, amiridin and HP-029. These results suggest that SM-10888 is an adequate drug for increasing the brain ACh content with less peripheral cholinergic side effects than THA, amiridin, HP-029 and physostigmine.

Aminacrine↗
PubMed1990

Effect of a novel CNS-selective cholinesterase inhibitor, SM-10888, on habituation and passive avoidance responses in mice.

The effects of the tacrine (THA) derivative SM-10888 (9-amino-8-fluoro-1,2,3,4-tetrahydro-2,4-methanoacridine citrate) on habituation and passive avoidance responses were studied in mice. We examined its effects on habituation of exploratory activity, measured by photo-cell beam interruptions in a small, simple cage and cycloheximide (CXM)- or electroconvulsive shock (ECS)-induced stepdown type passive avoidance response (PAR) failures in comparison with those of THA, amiridin, HP-029 and physostigmine. SM-10888 (6 mg/kg, p.o.) administered post-acquisition session enhanced the retention of habituation. CXM- and ECS-induced PAR failures were improved by SM-10888 (6 mg/kg, p.o.) administered at pre-training or post-training, respectively. THA enhanced the retention of habituation and improved CXM-induced PAR failure at 30 mg/kg, p.o., but did not affect ECS-induced PAR failure at 1-15 mg/kg, p.o. Amiridin and HP-029 were also effective on habituation and CXM-induced PAR failure at 40-50 mg/kg, p.o., but did not affect ECS-induced PAR failure at the tested doses. Physostigmine showed a moderate improvement only in CXM-induced PAR failure. The results indicate that SM-10888 enhanced habituation and improved PAR failures at much lower doses than THA. This seems to depend on its high selectivity to the central nervous system.

Aminacrine↗
PubMed1989

Liquid chromatographic-atmospheric pressure ionization mass spectrometric analysis of toremifene metabolites in human urine.

A liquid chromatographic-atmospheric pressure ionization mass spectrometric method has been developed for the analysis of toremifene metabolites in human urine after oral administration. This ionization source is a useful device for studying metabolites of toremifene because the total effluent from high-performance liquid chromatography is fed through an interface with a direct heating nebulizer and vaporizer at atmospheric pressure. To obtain good sensitivity the use of the right mobile phase is very important: ammonium acetate in methanol in the case of toremifene and its metabolites. Four unconjugated and three glucuronide-conjugated metabolites were detected in human urine. The majority of these were new and distinguishable from known metabolites.

Antineoplastic Agents↗
PubMed1989

Differential effects of alpha-, beta- and gamma-cyclodextrins on human erythrocytes.

Alpha-, beta- and gamma-cyclodextrins are cyclic hexamers, heptamers, and octamers of glucose, respectively, and thus are hydrophilic; nevertheless, they have the ability to solubilize lipids through the formation of molecular inclusion complexes. The volume of lipophilic space involved in the solubilization process increases with the number of glucose units in the cyclodextrin molecule and, consequently, cyclodextrins were found to have different effects on human erythrocytes: (a) in the induction of shape change from discocyte to spherocyte the potency was observed to be alpha greater than gamma, but with beta-cyclodextrin hemolysis occurred before the change was complete; (b) in the increase of fluorescence intensity of 1-anilinonaphthalene-8-sulfonate in cyclodextrin-pretreated membranes, the observed potency was beta much greater than gamma greater than alpha; (c) in the release of potassium and hemoglobin, the potency was beta greater than alpha greater than gamma. The potencies of cyclodextrin for solubilizing various components of erythrocytes were alpha greater than beta much greater than gamma for phospholipids, beta much greater than gamma greater than alpha for cholesterol and beta much greater than gamma greater than alpha for proteins. The solubilization potencies were derived from concentration/final-effect curves. The above processes occurred without entry of solubilizer into the membrane, since (a) beta-[14C]cyclodextrin did not bind to erythrocytes and (b) cyclodextrins did not enter the cholesterol monolayer. A study of the [3H]cholesterol in erythrocytes indicated that beta-cyclodextrin extracted this lipid from membrane into a new compartment located in the aqueous phase which could equilibrate rapidly with additional erythrocytes. Therefore, the effects of cyclodextrins differ from those of detergents which first incorporate themselves into membranes then extract membrane components into supramolecular micelles.

Cyclodextrins↗
PubMed1989

Alkylation of cyclomalto-oligosaccharides (cyclodextrins) with dialkyl sulfate-barium hydroxide: heterogeneity of products and the marked effect of the size of the macrocycle.

The alkylation of cyclomalto-oligosaccharides (cyclodextrins, CDs) with dialkyl sulfate-barium hydroxide has been claimed to yield 2,6-di-O-alkyl derivatives. Re-investigation by plasma desorption-m.s. of the products of laboratory methylation of alpha CD, beta CD, or gamma CD and ethylation of beta CD and several commercial preparations revealed them to be mixtures with broad and roughly symmetrical distributions of the degree of substitution. Recrystallization separated the components only partially. Analysis of the product of methylation of a mixture of CDs established the order of reactivity gamma much greater than alpha greater than or equal to beta. The reactivity of gamma CD thus resembles that of amylose.

Alkylation↗
PubMed1989

O-carboxymethyl-O-ethylcyclomaltoheptaose as a delayed-release-type drug carrier: improvement of the oral bioavailability of diltiazem in the dog.

The utility of O-carboxymethyl-O-ethylcyclomaltoheptose (carboxymethyl-ethyl-beta-cyclodextrin, CME-beta CD) as a delayed-release-type drug carrier was investigated in vitro and in vivo, using diltiazem hydrochloride as a model drug. The aqueous solubility of CME-beta CD showed a marked dependency on pH, because of the ionization of the carboxyl group (pKa 3.75). The formation of an inclusion complex between diltiazem and CME-beta CD in aqueous solution and in the solid state was assessed by a solubility method and by X-ray diffractometry, respectively. The rate of release of the drug from the compressed tablet containing the complex was significantly retarded in solutions at low pH and increased with increase in pH, and this was reflected in the blood levels in the dog after the oral administration. The results suggested that the use of CME-beta CD could improve the oral bioavailability of diltiazem and release the drug preferentially in the intestinal fluid but only slightly in the gastric fluid.

Absorption↗
PubMed1989

An attempt to reduce the photosensitizing potential of chlorpromazine with the simultaneous use of beta- and dimethyl-beta-cyclodextrins in guinea pigs.

The effects of topically applied beta-cyclodextrin (beta-CyD) and heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) on photoallergic contact dermatitis due to chlorpromazine hydrochloride (CPZ) were investigated using the photomaximization technique in guinea pigs. From the gross and histological observations, the photosensitizing potential of CPZ with the simultaneous topical use of beta-CyDs was significantly lower than that of CPZ alone. The alleviating efficacy of DM-beta-CyD was greater than that of beta-CyD. beta-CyDs suppressed the penetration of CPZ into the skin through the formation of poorly skin-permeable complexes. In addition, beta-CyDs inhibited (a) the photoinduced free radicals derived from CPZ in the isolated dry skin and (b) the in vitro photochemical binding of CPZ to bovine serum albumin. These observations suggest that beta-CyDs suppress the photochemical reactions between CPZ and biological macromolecules present in the skin, resulting in the failure to form a photoantigen. The present results indicate that DM-beta-CyD is particularly effective in alleviating photoallergic contact dermatitis due to CPZ.

Animals↗
PubMed1989

Increased fibrinopeptide A during anginal attacks in patients with variant angina.

It is not known whether coronary vasospasm is associated with coronary thrombosis. In this study, plasma levels of fibrinopeptide A during anginal attacks in 24 patients with variant angina were examined. A hyperventilation test was used to induce angina. Hyperventilation induced angina and ST segment elevation (AST: 0.32 +/- 0.14 mV, p less than 0.01) in eight patients with variant angina. Fibrinopeptide A increased from 0.75 +/- 0.27 at control to 7.8 +/- 4.4 ng/ml (p less than 0.01) during anginal attacks in these eight patients. In addition, four patients had spontaneous attacks of angina; they also had elevated levels of fibrinopeptide A during attacks (from 2.0 +/- 1.2 at control to 21.9 +/- 18.0 ng/ml [p less than 0.01] during attacks). Hyperventilation did not induce either angina or ST segment elevation in 12 of the patients with variant angina. Fibrinopeptide A levels did not change with hyperventilation in these patients. To determine whether elevated plasma levels of fibrinopeptide A were associated with angina, the plasma levels of fibrinopeptide A were examined during exercise-induced angina in seven additional patients with stable effort angina. They all developed angina with treadmill exercise; however, plasma fibrinopeptide A did not change. Therefore, only the patients with variant angina demonstrated elevated levels of fibrinopeptide A during anginal attacks. These findings suggest that coronary vasospasm associated with myocardial ischemia may induce stasis of blood, resulting in fibrinogen-fibrin conversion in the coronary vessels.

Angina Pectoris, Variant↗
PubMed1989

Sustained release of buserelin acetate, a luteinizing hormone-releasing hormone agonist, from an injectable oily preparation utilizing ethylated beta-cyclodextrin.

The possible use of heptakis (2,6-di-O-ethyl)-beta-cyclodextrin (DE-beta-CyD) as a parenteral sustained-release carrier for buserelin acetate, a luteinizing hormone-releasing hormone superagonist, has been examined. The in-vitro release of buserelin from the oily suspension was significantly retarded by the complexation with DE-beta-CyD, mainly due to the poor water solubility of the complex. A single subcutaneous injection of the suspension containing the buserelin-DE-beta-CyD complex to rats provided an effective continuous plasma level of buserelin lasting for at least one month, indicating a potential therapeutic efficacy for the treatment of the endocrine-dependent diseases. These results suggest that DE-beta-CyD serves as an injectable sustained-release drug carrier suitable for chronic treatment with buserelin acetate.

Animals↗