Biomedical subjects

K Satoh

Publications and source records attributed to K Satoh.

At least 1,297 records · Page 72Linked to original sources

PubMedDate not supplied

Separation of the coronary vasodilator from the cardiac effects of PN 200-110, a new dihydropyridine calcium antagonist, in the dog heart.

Coronary vasodilator and cardiac effects of PN 200-110 were compared by use of isolated, blood-perfused sinoatrial (SA) node, atrioventricular (AV) node, and papillary muscle preparations of dogs. PN 200-110 was administered intraarterially. In all preparations PN 200-110 produced an increase in coronary blood flow. In SA node preparations, the drug produced a decrease in sinus rate and atrial standstill as well, but only in large doses. The dose that produced a 15% (nearly half-maximum) decrease in sinus rate was about three times the dose that doubled coronary blood flow. In AV node preparations, the drug produced an increase in AV conduction time and, in large doses, second- or third-degree AV block only when it was injected into the artery supplying the AV node. The dose that produced a 15% (nearly half-maximum) increase in AV conduction time was approximately 12 times the dose that doubled coronary blood flow. In paced papillary muscle preparations, the drug produced a decrease in the force of contraction. However, the dose that produced a 50% decrease in the force of contraction of the papillary muscle was approximately 14 times the dose that doubled coronary blood flow. These effects of PN 200-110 were of long duration. The drug was entirely ineffective in changing the rate of ventricular automaticity. The order of selectivity of PN 200-110 was as follows: coronary blood flow greater than SA nodal automaticity greater than AV nodal conduction greater than ventricular muscle contraction. This cardiovascular profile of PN 200-110 is slightly different from that of PY 108-068, a compound closely related to PN 200-110 in chemical structure.

Animals↗

PubMedDate not supplied

The mechanism underlying the vasodilator action of bunitrolol: contribution of alpha 1-adrenoceptor blocking action.

The mechanism of the vasodilator action of bunitrolol was investigated in pentobarbital-anesthetized dogs. When injected intraarterially, bunitrolol increased blood flow through the femoral arterial bed more effectively than that through the vascular bed of the left anterior descending coronary artery (LAD). The former is rich in alpha-adrenoceptors and tonically controlled by the sympathetic nerves, whereas the latter is not. Intraarterial prazosin increased femoral flow but not LAD flow, whereas intraarterial nitrendipine increased equieffectively both femoral and LAD flows. In the saphenous arterial bed of dogs that also underwent spinal anesthesia and received atropine and nadolol, intravenous bunitrolol suppressed more effectively vasoconstrictor responses to saphenous nerve stimulation than those to intraarterial norepinephrine. These effects of bunitrolol were similar to those of prazosin and dissimilar to those of yohimbine. In similarly treated dogs, bunitrolol suppressed more effectively increases in mean systemic arterial pressure in response to methoxamine than those to B-HT 920. From these results, it was concluded that an alpha 1-adrenoceptor blocking action is mainly involved in the acute vasodilator effect of bunitrolol. This action may also contribute to the decrease in total peripheral resistance seen in hypertensive patients treated chronically with bunitrolol.

Anesthesia, Spinal↗

PubMedDate not supplied

Assessment of the coronary vasodilator action of SK&F 24260 in the dog.

1. The effects of SK&F 24260 administered intravenously or intraduodenally on the coronary outflow, coronary arteriovenous oxygen difference (A-V O2), myocardial oxygen consumption (MVO2), systemic blood pressure, heart rate and atrioventricular (AV) conduction time were examined in open-chest dogs. 2. SK&F 24260 in doses of 0.3-10 microgram/kg, i.v., caused a dose-dependent increase in coronary sinus outflow, but the increase was smaller with 30 microgram/kg, i.v., than with 10 microgram/kg, i.v. 3. SK&F 24260 (0.3-30 microgram/kg, i.v.) decreased A-V O2 and MVO2 in a dose-dependent manner. 4. SK&F 24260 (0.3-30 microgram/kg, i.v.) decreased systemic blood pressure and heart rate, and increased AV conduction time. 5. Intraduodenal administration of SK&F 24260 (1 mg/kg) produced almost the same effects on coronary sinus outflow, A-V O2, MVO2, systemic blood pressure, heart rate and AV conduction time as did the intravenous administration of the compound (10 microgram/kg). 6. The property of SK&F 24260 to increase the coronary blood flow and to moderately decrease MVO2, systemic blood pressure and heart rate indicates that this agent is a potential antianginal drug.

Animals↗

PubMedDate not supplied

Pharmacological profile of a new coronary vasodilator drug, 2-nicotinamidoethyl nitrate (SG-75).

1. In anaesthetized, open-chest dogs, 2-nicotinamidoethyl nitrate (SG-75) administered intravenously (0.3-1 mg/kg) or intraduodenally (3 mg/kg) produced decrease in systemic blood pressure, coronary resistance, heart rate and an increase in coronary sinus outflow, but virtually no change in myocardial oxygen consumption and atrioventricular conduction. The effects of SG-75 administered intraduodenally emerged within a few minutes after dosing and lasted over about 1 h. 2. In isolated, blood-perfused sino-atrial node preparations of the dog SG-75 administered into the sinus node artery decreased slightly sinus rate at the dose which doubled blood flow through the artery. 3. In isolated, blood-perfused atrioventricular node preparations of the dog SG-75 administered into the atrioventricular node artery did not impair atrioventricular conduction even in doses which increased blood flow through the artery to more than twice the basal level. 4. In isolated, blood-perfused papillary muscle preparations of the dog SG-75 administered into the anterior septal artery scarely affected force of contraction of the papillary muscle at the dose which doubled blood flow through the artery, although in further large doses it produced a transient decrease in the force of contraction. In extremely large doses it produced ventricular fibrillation. 5. In anaesthetized, open-chest dogs in which cardiac input was kept constant SG-75 (0.01-1 mg/kg) administered into the ascending aorta increased venous return without changing systemic output. 6. 2-Nicotinamidoethyl alcohol, a denitrated compound of SG-75, had no vasodilator action in doses comparable to those of the parent compound. 7. These results indicate SG-75 to be a potential antianginal drug having no cardiodepressant actions but having properties uncharacteristic of the nitrates.

Animals↗

PubMedDate not supplied

Mechanisms underlying the cardiovascular action of a new dihydropyridine vasodilator YC-93.

1. The mechanisms underlying the cardiovascular action of YC-93, a new dihydropyridine vasodilator with cyclic AMP phosphodiesterase inhibitory activity, was investigated by comparing its effects with those of papaverine in various isolated, blood-perfused heart preparations of the dog. 2. In all preparations YC-93 injected into the nutrient arteries produced a dose-dependent increase in blood flow, and in this respect YC-93 was about twenty times more potent than papaverine on a weight basis. 3. In sinoatrial node preparations YC-93 injected into the sinus node artery decreased sinus rate in a dose-dependent manner, and in large doses produced atrial standstill. 4. In atrioventricular (a.v.) node preparations YC-93 injected into the a.v. node artery increased a.v. conduction time in a dose-dependent manner, and in large doses produced a second or third degree block of a.v. conduction. However YC-93 injected into the anterior septal artery scarcely affected a.v. conduction. 5. In spontaneously contracting papillary muscle preparations YC-93 injected into the anterior septal artery failed to affect ventricular automaticity in doses which markedly decreased developed tension of papillary muscles. 6. In papillary muscle preparations driven at a fixed rate YC-93 injected into the anterior septal artery produced a dose-dependent decrease in developed tension of papillary muscles. 7. Unlike YC-93, papaverine decreased a.v. conduction time in a.v. node preparations and increased developed tension of papillary muscle preparations. 8. The cardiac effects of YC-93 elucidated in the present experiments are characteristic of calcium-antagonistic vasodilators. The action of YC-93 as an inhibitor of cyclic AMP phosphodiesterase does not appear to play a role in its cardiac action.

Animals↗

PubMedDate not supplied

Eye movements induced by electrical stimulation in the rabbit's mesodiencephalon.

32 adult albino rabbits were used to investigate the oculomotor function of the mesodiencephalon. Bipolar electrical stimulation was used to induce saccades in unanesthetized rabbits. Saccades were induced from relatively broad regions of the rabbit's mesodiencephalon except for tractus opticus, a part of nucleus lateralis posterior thalami and some parts of nucleus pretectalis anterior. The direction of the saccades was generally ipsilateral to the stimulation site. Although the saccades were not influenced by caloric nystagmus or in blindfolding, the pattern of them was greatly influenced by a lateral recumbent position. Nystagmus was induced from tractus opticus, nucleus pretectalis anterior and nucleus lateralis posterior thalami. The nystagmus became remarkable in blind-folding, or when an eye ipsilateral to the stimulation site was covered. This electrically induced nystagmus did not undergo any modulations by ablation of the flocculus and paraflocculus contralateral to the stimulation site.

Animals↗

PubMedDate not supplied

Rhabdomyosarcoma of the urachus. A case report.

BACKGROUND: Rhabdomyosarcoma of the urachus is extremely rare, and only two cases have been reported. Cytologic, histologic, immunochemical and electron microscopic findings in embryonal rhabdomyosarcoma of the urachus are presented. CASE: Embryonal rhabdomyosarcoma of the urachus developed in a 2-year-old boy. Imprint smears prepared prior to a histologic examination for a rapid report contained many malignant cells isolated or in clusters in a myxoid background. They were uniformly small, with round to oval nuclei and scant cytoplasm, and immunohistochemically positive for desmin and alpha-sarcomeric muscle actin but negative for myoglobin. This tumor was diagnosed cytologically as embryonal rhabdomyosarcoma because of its skeletal muscle origin and because of its similarity to one of the so-called small round cell tumors of childhood. Histologic examination confirmed the cytologic diagnosis. CONCLUSION: Cytologic, histologic and electron microscopic findings were identical to those described previously for embryonal rhabdomyosarcoma at other sites. In immunochemical examinations, cytologic samples fixed in ethanol are more useful than histologic ones fixed in formalin. Then, in order to differentiate poorly differentiated rhabdomyosarcoma from other small round cell tumors in children, desmin and alpha-sarcomeric actin, rather than myoglobin, are recommended.

Actins↗

PubMedDate not supplied

Effects on health of dietary supplementation with 100 mg d-alpha-tocopheryl acetate, daily for 6 years.

To evaluate the clinical antioxidant effects of vitamin E, 161 healthy volunteers aged 39 to 56 years, were given 100 or 3 mg of d-alpha-tocopheryl acetate orally daily for 6 years using a randomized, double-blind design. Among the 147 volunteers who qualified for the analysis, seven of the 73 volunteers receiving 3 mg d-alpha-tocopheryl acetate daily and none of the 74 volunteers receiving 100 mg had coronary disorders including myocardial damage (P < 0.02). ST or T wave abnormalities on electrocardiograms were considered to indicate coronary disorders (four volunteers). The mean serum total tocopherol (TOC) concentration in the 100-mg group was significantly higher than that in the 3-mg group 6 months after the start of the study, and this raised value was maintained throughout the study; the level in the 3-mg group did not change significantly from the baseline value. The low-density lipoprotein cholesterol/total TOC ratio, a parameter of the inhibition of peroxidation of low-density lipoprotein cholesterol, was the only serum lipid parameter that was significantly different, at baseline, in the volunteers with coronary disorders compared with the others. These findings indicate that long-term supplementation with 100 mg tocopheryl acetate daily may prevent the early stages of coronary atherosclerosis by decreasing peroxidation of low-density lipoprotein cholesterol.

Adult↗

PubMedDate not supplied

Investigation of ovum transport in the oviduct: the dynamics of oviductal fluids in domestic rabbits.

Ova are captured by the oviductal fimbria and rapidly transported to the ampullary-isthmic junction of the fallopian tube. Fertilized ova and oviductal fluids are then carried medially in the fallopian tube, while undergoing maturation in preparation for entering the uterine cavity, where nidation and further development take place. This movement of oviductal fluids was visualized in a rabbit model with human chorionic gonadotropin-induced ovulation, by injection of a contrast medium into the ampulla region of the oviduct. In the ampulla, the opaque medium was observed to oscillate at 0-85.4 mm/s. This medial transport of the fluid towards the uterus decreased to 0-9.6 mm/s in the isthmic portion of the tube. This decrease substantiates previous findings that the transport of material in the isthmic portion of the oviduct is more strongly under the control of ciliary action than under peristaltic activity.

Animals↗

PubMedDate not supplied

The effect of cross-linked hyaluronate hydrogel on the reduction of post-surgical adhesion reformation in rabbits.

The effects of cross-linked hyaluronate hydrogel and liquid sodium hyaluronate on post-surgical adhesion reformation were examined using a rabbit model. Primary adhesions in the ileocaecal region of Japanese white rabbits were induced by mechanical and chemical irritants during laparotomy. After 1 month the primary adhesions were lysed by microsurgery and cross-linked hyaluronate hydrogel or liquid sodium hyaluronate was applied to the lysed lesions. After 10-14 days the area of adhesion reformation was measured to assess any inhibitory effect of the test materials. Rabbits treated with cross-linked hyaluronate hydrogel showed a significant reduction in adhesion reformation area compared with liquid sodium hyaluronate or physiological saline treatment, and the area reduced to (mean +/- standard deviation) 0.6 +/- 1.95% of the original lesion. In a separate study, histological evaluation of rabbits treated with cross-linked hyaluronate hydrogel revealed a better healing pattern and a lower inflammatory response compared with controls. All these findings suggest cross-linked hyaluronate hydrogel may be a valuable anti-adhesion material to prevent post-surgical adhesion in abdominal or pelvic surgery.

Animals↗

PubMedDate not supplied

Use of fibrin adhesive to reduce post-surgical adhesion reformation in rabbits.

Following surgery on fallopian tubes, the development of adhesions is a natural consequence of wound healing and may result in infertility. Using a rabbit model, we evaluated the anti-adhesive properties of a sponge-like equine collagen sheet (TachoComb), which is coated on one side with human fibrinogen and bovine thrombin. TachoComb is applied by affixing the sheet over the area of perforation or bleeding and acts as a haemostatic agent, capable of sealing perforations to prevent leakage. In our rabbit model, adhesions were induced by mechanical and chemical irritants during laparotomy. After a 1-month recovery period, adhesions were lysed using microsurgical techniques and TachoComb, or physiological saline applied. Evaluation of adhesion reformation was determined after a minimum of 10 days. TachoComb significantly reduced the area of adhesion reformation compared with rabbits treated using physiological saline only. Our study demonstrated that TachoComb is effective not only as a haemostatic agent, but is also capable of reducing adhesion reformation.

Animals↗

PubMedDate not supplied

Clinical evaluation of a haemostatic and anti-adhesion preparation used to prevent post-surgical adhesion.

TachoComb consists of equine collagen in a sponge-like form coated on one side with human fibrinogen and bovine thrombin. This product functions as a haemostatic and physical barrier to inhibit post-surgical adhesion. In this study, we investigated TachoComb to control oozing in 16 patients who required haemostasis. Evaluation of post-surgical adhesion by second-look laparoscopy was performed at 3 months and 7 months after initial surgery. Observation via laparotomy during Caesarean section was also performed at 13 months, 3 years and 4 years after initial surgery. In all but one patient, no macroscopic evidence of TachoComb persistence was found. Furthermore, no de novo adhesions were detected at the TachoComb application site. We have thus demonstrated that TachoComb can be used to control oozing haemorrhage effectively from surgical sites and can prevent adhesion formation at the application site, and may thus be an effective method of preventing adhesion-induced infertility.

Adult↗

PubMedDate not supplied

Production of hydrogen peroxide in cancerous tissue by intravenous administration of sodium 5,6-benzylidene-L-ascorbate.

We investigated whether the antitumor action of sodium 5,6-benzylidene-L-ascorbate (SBA) is mediated via oxidation-involved mechanism, in three different systems: 3'-methyl-4-dimethylaminoazobenzene (DAB)-induced rat hepatocellular carcinoma (in vivo), its homogenate (semi in vivo), and cultured cells (in vitro). Oral intake of DAB irreversibly produced hepatocellular carcinoma in rats, with a maximum incidence of carcinogenesis after 4 months. Intravenous administration of SBA induced vacuolar, eosinophilic degeneration and nuclear debris, producing greater amounts of ESR signal of ascorbate radical and hydrogen peroxide (H2O2)-derived chemiluminescence (CL) (H2O2-CL) in the cancerous tissue than in the normal tissue. When SBA was directly added to the homogenates, higher amounts of ascorbate radical and H2O2-CL were generated in cancerous tissues. When SBA was added to the RPMI1640 medium supplemented with 10% fetal bovine serum, methionine was oxidized to methionine sulfoxide and H2O2 was produced in amounts that sufficiently induce apoptotic cell death in human promyelocytic leukemic HL-60 cells. Cytotoxic activity of SBA was significantly reduced by catalase. These data suggest that antitumor activity of SBA in vivo might at least in part be due to H2O2, produced from SBA.

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PubMedDate not supplied

Radical modulation activity of pine cone extracts of Pinus elliottii var. Elliottii.

The radical modulation activity of lignins prepared from the cone of Pinus elliottii var. Elliottii was investigated, using ESR spectroscopy. These lignins produced radical(s) under alkaline conditions, and the radical intensity was increased with increasing pH. Lower concentrations of lignins slightly reduced the radical intensity of sodium ascorbate, whereas higher concentrations of lignins enhanced both the radical intensity and cytotoxic activity of sodium ascorbate. Lignins effectively scavenged superoxide anion, produced by hypoxanthine-xanthine oxidase reaction. Elliottii lignins significantly inhibited the human immunodeficiency virus (HIV)-induced cytopathic effect, in similar fashions to other natural, commercial and synthetic lignins. Pretreatment of mice with lignins significantly protected them from the lethal infection with E. coli. Crude alkaline extracts of Elliottii pine cone displayed similar magnitude of activity with lignins. These data further supports the medicinal efficacy of plant extracts.

Animals↗

PubMedDate not supplied

Prevention of oral diseases by polyphenols (review).

This review summarizes the current data on the effects of natural products on various oral diseases, together with their basic biological activities. We have focused on polyphenols and their secondary metabolites, such as tannins, lignins and flavonoids, and their modulating factors, including saliva proline-rich proteins. These substances are found in a wide variety of plant sources such as vegetables, herbs, nuts and teas, and effectively reduce the incidence of carcinogenesis in the oral cavity, inhibit plaque growth and adsorption of oral bacteria, and inhibit the replication of various viruses. The mechanism of their action includes: the direct inactivation of the bacteria and viruses, inhibition of their replication enzymes, induction of apoptosis in tumor cells, stimulation of monocytes/macrophages to produce cytokines, and stimulation of myeloperoxidase-dependent iodination of neutrophiles. Polyphenols showed biphasic actions, acting as antioxidants at lower doses, but acting as prooxidants at higher doses. The development and progression of oral diseases might be modified not only by these natural products, but also by interaction with saliva, proline-rich proteins, antioxidants, metals and dental materials.

Animals↗

PubMedDate not supplied

Relationship between radical intensity and biological activity of cacao husk extracts.

The relationship between radical intensity and biological activity of cacao husk extracts was investigated. Electron spin resonance (ESR) spectroscopy demonstrated that the radical intensity of hexane, acetone, methanol and 70% methanol extracts increased with water-solubility. Several fractions of these husk extracts, separated by different column chromatographies, significantly inhibited the cytopathic effect of human immunodeficiency virus (HIV) infection in parallel with their radical intensity. However, their cytotoxic activity against human leukemic and carcinoma cell lines is not always correlated with their radical intensity. Water-soluble and lipophilic compounds might induce cytotoxic activity by different mechanisms.

Anti-HIV Agents↗

PubMedDate not supplied

Interaction between sodium 5,6-benzylidene-L-ascorbate and gallic acid.

The interaction between sodium 5,6-benzylidene-L-ascorbate (SBA) and gallic acid was investigated by two different parameters: radical intensity and cytotoxicity induction. These compounds produced ESR signals of radicals under alkaline conditions. The addition of increasing concentrations of SBA completely scavenged the gallate radical and replaced the latter with its ascorbate radical. On the other hand, gallic acid dose-dependently enhanced the radical intensity of SBA. Both of these two compounds dose-dependently reduced the viable cell number of human squamous carcinoma HSC-2 cells without inducing internucleosomal DNA cleavage. Electron micrographs of the dying cells demonstrate the irreversible degenerative changes especially in the cytoplasm of the cells. The cytotoxic activity of gallic acid was almost completely eliminated by catalase, whereas SBA was totally insensitive to catalase. When these two compounds were mixed together before adding to HSC-2 cells, the cytotoxic activity of gallic acid was significantly reduced by SBA, whereas that of SBA was not reduced by gallic acid. SBA dose-dependently reduced the gallate oxidation in the culture medium. The interaction between SBA and gallic acid may modify their individual biological activity.

Antineoplastic Agents↗

PubMedDate not supplied

Pharmacologically stimulated portal flow measurement by magnetic resonance imaging for assessment of liver function.

PURPOSE: To evaluate pharmacologically stimulated portal flow measured by magnetic resonance (MR) imaging for assessment of liver function. MATERIALS AND METHODS: Pharmacologically stimulated portal flow was measured by phase contrast MR imaging in 27 patients when they were undergoing abdominal angiography for liver tumors or gall bladder cancer. The patients included 11 cases of liver cirrhosis and eight of chronic hepatitis. Pharmacological stimulation was done by infusion of 10 microg/Kg of nicardipine hydrochloride into the superior mesenteric artery through an angiographic catheter. We examined the correlation between stimulated or non-stimulated portal flow and biochemical liver function tests. RESULTS: Correlation coefficients and their corresponding p values between non-stimulated portal flow and the indocyanine green residual rate at 15 min after injection (ICG R15), serum albumin (ALB), total bilirubin (TB), cholinesterase (CHE), and hepaplastin test (HP) were--0.414 (0.056), 0.296 (0.134), -0.570 (0.002), 0.289 (0.153), and 0.321 (0.126), respectively, whereas those between stimulated portal flow and ICG R15, ALB, TB, CHE, and HP were--0.561 (0.007), 0.411 (0.033), -0.509 (0.007), 0.445 (0.023), and 0.494 (0.014), respectively. CONCLUSION: Stimulated portal flow showed better correlations with biochemical liver function tests than non-stimulated portal flow. It is suggested that stimulated portal flow measurement is more useful for the evaluation of liver function than non-stimulated portal flow measurement.

Aged↗