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Biomedical subjects

K Satoh

Publications and source records attributed to K Satoh.

At least 1,225 records · Page 68Linked to original sources
PubMed1979

Significance of the quantification and demonstration of hyaluronic acid in tissue specimens for the diagnosis of pleural mesothelioma.

Hyaluronic acid in pleural tissues from patients with mesothelioma, carcinoma, and asbestosis of the lung was quantified by using specific glycosaminoglycan-degrading enzymes. In all cases of pleural mesothelioma, the quantity of hyaluronic acid in mg/g of dry tissue was at least 0.10 mg, whereas carcinomatous pleural tissue and pleura in asbestosis contained 0.02 to 0.03 mg/g of dry tissue.

Asbestosis↗
PubMed1979

Circumstantial evidence for increased potassium conductance of membrane of cardiac muscle by 2-nicotinamidoethyl nitrate (SG-75).

The mechanism of action of 2-nicotinamidoethyl nitrate (SG-75), was investigated by the use of arterially blood-perfused papillary muscle preparations of the dog. All drugs were administered intra-arterially. SG-75 shortened the effective refractory period (ERP) and decreased the rate of automaticity and developed tension of the papillary muscle, whereas verapamil failed to change the ERP despite a decrease in the developed tension. SG-75 in extremely high doses induced ventricular fibrillation. Methacholine produced decreases in the rate of automaticity and developed tension, and the actions were abolished by atropine. The SG-75-induced decreases in two parameters were not modified by atropine. These results indicate that the cardiac action of SG-75 differs from that of calcium-antagonistic vasodilators and it is suggested that the basic mechanism of action of SG-75 involves an increase in potassium conductance in the membrane of cardiac muscle, without mediation through muscarinic receptors.

Animals↗
PubMed1979

Simultaneous assessment of the effects of trimetazidine on the myocardium and coronary vasculature of the dog.

The effects of trimetazidine on the electrical and mechanical activities of the myocardium were investigated in comparison with the effect on the coronary blood flow in blood-perfused preparations excised from dog hearts. In the sinoatrial (SA) node preparation trimetazidine injected into the sinus node artery increased blood flow and depressed SA node automaticity. In the atrioventricular (AV) node preparation trimetazidine injected into the AV node artery or the anterior septal artery increased blood flow and equally prolonged AV conduction time. In the papillary muscle preparation trimetazidine injected into the anterior septal artery increased blood flow and depressed force of contraction. These cardiodepressant actions occurred in the same range of doses of trimetazidine that exerted the vasodilator action. This indicates that trimetazidine has no selective activity on the coronary vasculature alone. Moreover, the vasodilator effect was more short-lived than the cardiodepressant action. Trimetazidine injected into the anterior septal artery affected ventricular bipolar electrograms. This, taken together with the prolongation of AV conduction time obtained with the same route of administration, suggests that the cardiodepressant action of trimetazidine is ascribed to the local anaesthetic or the membrane stabilizing action rather than to the calcium-antagonistic action.

Animals↗
PubMed1979

The origin of reticulospinal fibers in the rat: a HRP study.

The distribution as well as morphological characteristics of brain stem reticular neurons projecting to spinal cord both of aminergic and non-aminergic natures in the rat was investigated by means of the retrograde horseradish peroxidase (HRP) method. For the identification of aminergic neurons, a combination of HRP technique and monoamine-oxidase staining as well as a pretreatment of 6-hydroxydopamine and 5,6-dihydroxytryptamine (5,6-DHT) was applied. Following the injection of HRP to the cervical, thoracic and lumbar cord, a remarkable number of neurons in the nuclei reticularis ventralis (rv), reticularis lateralis (RI; Meesen & Olszewski), reticularis gigantocellularis, reticularis pontis caudalis, reticularis pontis oralis (rpo), and a small number of cells in the nucleus reticularis dorsalis dorsalis as well as the mesencephalic reticular nuclei were found to be labeled. In the case of cervical injection, HRP labeled cells were also found in the nucleus reticularis parvocellularis, adjacent to the nucleus tractus spinalis n. trigemini oralis, in which labeled neurons were observed. Within Rl, ventral division of rv and lateral part of rpo, the labeled noradrenaline neurons in A 1, 3 and 7, respectively, were found intermingled with the non-aminergic labeled neurons. Many neurons in the nucleus raphe magnus (ram), obscurus (rao) and pallidus (rap) were labeled. From the fact that there was a marked decrease in the number of the labeled cells in rao, rap, and a slight decrease in ram after 5,6-DHT treatment, it was suggested that the majority of labeled cells in rao, rap and a partial number of labeled cells in ram are serotonergic.

Animals↗
PubMed1978

Serum lipid peroxide in cerebrovascular disorders determined by a new colorimetric method.

A new colorimetric method for quantitative analysis of serum lipid peroxide, free of interference from sialic acids, has been developed. We have used the thiobarbituric acid dissolved in sodium sulfate solution and both liberation of lipid peroxide and color reaction have been performed simultaneously by heating serum protein precipitate with this reagent in a weak acid solution. The new method is specific and facilitates the precise measurements of serum lipid peroxide. The average values determined by the new method increased slightly with age in healthy subjects. In patients with sequelae of cerebrovascular disorders, serum lipid peroxide values were higher than in healthy controls. These results may demonstrate the important role of lipid peroxide in aging and cerebrovascular disorders.

Cerebrovascular Disorders↗
PubMed1978

Excitation of autonomic nerves by 4-aminopyridine in the isolated, blood-perfused sino-atrial node preparation of the dog.

4-Aminopyridine injected into the sinus node artery produced a long-lasting decrease in sinus rate preceded by a transient increase. With a large dose, a long-lasting increase in sinus rate was superimposed on the long-lasting decrease phase. The long-lasting decrease and increase in sinus rate were abolished by 1-hyoscyamine and propranolol respectively, and both were reduced by tetrodotoxin. These results can be interpreted as being due to excitation of autonomic nerves by 4-aminopyridine.

Animals↗
PubMed1978

Competition between the 735 nm fluorescence and the photochemistry of Photosystem I in chloroplasts at low temperature.

Fluorescence emission spectra of chloroplasts, initially frozen to--196 degrees C, were measured at various temperatures as the sample was allowed to warm. The 735 nm emission band attributed to fluorescence from Photosystem I was approx. 10-fold greater at--196 degrees C than at--78 degrees C. The initial rate of photooxidation of P-700 was also measured at--196 degrees C and--78 degrees C and was found to be approximately twice as large at the higher temperature. It is proposed that the 735 nm emission band is fluorescence from a long wavelength form of chlorophyll, C-705, which acts as a trap for excitation energy in the antenna chlorophyl system of Photosystem I. Furthermore, it is proposed that C-705 only forms on cooling to low temperatures and that the temperature dependence of the 735 nm emission is the temperature dependence for the formation of C-705. C-705 and P-700 compete to trap the excitation energy in Photosystem I. It is estimated from the data that at--78 degrees C P-700 traps approx. 20 times more energy than C-705 while, at--196 degrees C, the two traps are approximately equally effective. By analogy, the 695 nm fluorescence which also appears on cooling to--196 degrees C is attributed to traps in Photosystem II which form only on cooling to temperatures near--196 degrees C.

Chlorophyll↗
PubMed1978

Afferent fiber connections from lower brain stem to hypothalamus studied by the horseradish peroxidase method with special reference to noradrenaline innervation.

Attempts were made to determine the afferent projections to the anterior hypothalamus including the preoptic area from the lower brain stem by means of the horseradish peroxidase method combined with monoamine oxidase staining to identify noradrenaline (NA) neurons. In addition to this technique, a histofluorescence analysis was performed. NA fibers in the medial part of the anterior hypothalamus were mainly supplied by A1 and A2 NA neuron groups, while the lateral part and periventricular zone received NA terminals from both pontine and medulla oblongata NA neuron groups. Furthermore, the present study indicated that there were direct projections to the anterior hypothalamus from non-noradrenergic neurons in the lower brain stem: nuclei raphe dorsalis, centralis superior, cells in the mesencephalic and pontine central gray matter, nuclei parabrachialis lateralis and medialis, cells around fasciculus longitudinalis medialis.

Afferent Pathways↗
PubMed1978

Low temperature spectral properties of subchloroplast fractions purified from spinach.

Spinach (Spinacia oleracea L.) chloroplasts solubilized by digitonin were separated into five fractions by sucrose density gradient centrifugation. Three of the fractions, F(I), F(II), and F(III), corresponding to photosystem I, photosystem II, and the chlorophyll a/b complex, were purified further by two steps of diethylaminoethyl-cellulose chromatography followed by electrofocusing on an Ampholine column. The polypeptide patterns of the fractions were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the spectral properties of the fractions at -196 C determined by absorption spectra, fourth derivative curves of the absorption spectra, fluorescence emission spectra, and fluorescence excitation spectra. The activity of purified F(II) (photosystem II) was also assayed by the photoreduction of dichlorophenol-indophenol at room temperature using 1,5-diphenylcarbohydrazine as the electron donor and by the photoreduction of C-550 at -196 C. The different fractions showed unique polypeptide patterns and unique sets of low temperature-absorbing forms of chlorophyll. The fluorescence emission spectra of F(I), F(II), and F(III) at -196 C were also unique with maxima at 734, 685 and 681 nm, respectively. F(I) showed negligible emission at wavelengths shorter than 700 nm and the long wavelength tails of F(II) and F(III) in the 730 nm region were relatively small (approximately 10% of emission of their wavelength maxima). Addition of 0.1% Triton to F(I) and F(II) caused the longer wavelength absorbing forms of chlorophyll to shift to 670 nm and the fluorescence emission maxima (of both fractions) to shift to 679 nm at -196 C with an increase in the yield of fluorescence especially in the case of F(I).

Journal Article↗
PubMed1978

Role of the peripheral vasculature in changes in venous return caused by isoproterenol, norepinephrine, and methoxamine in anesthetized dogs.

We studied effects on venous return of alpha- and beta-adrenergic agonists in anesthetized dogs. Blood from the superior and inferior venae cavae (venous return) was drained at the level of the tricuspid valve into a reservoir, from which blood was pumped into the right atrium at a constant rate. Isoproterenol infused into the ascending aorta or the right atrium increased the venous return and heart rate and decreased systemic blood pressure. The increase in venous return produced by isoproterenol given into the right atrium was not significantly different from that produced by isoproterenol administered into the ascending aorta, although the increase in heart rate was more marked with the latter route of administration. Norepinephrine infused into the ascending aorta increased the systemic blood pressure, venous return, and heart rate. Methoxamine infused into the ascending aorta increased the systemic blood pressure and decreased the venous return but produced no change in heart rate. Isoproterenol increased the venous return even when the sinoaortic baroreceptor reflex was eliminated. Propranolol abolished the increase in venous return caused by isoproterenol and reversed the increase in venous return caused by norepinephrine. The results suggest that a decrease in venous resistance mediated through a beta-adrenergic mechanism is important in increasing venous return, whereas an increase in venous resistance mediated through an alpha-adrenergic mechanism is responsible for a decrease in venous return.

Animals↗
PubMed1978

Effects on atrio-ventricular conduction of propranolol, pindolol and carteolol in the dog heart in situ as assessed by automated devices.

In open-chest dogs the heart rate was controlled at 150 beats/min and drugs were given intravenously. Propranolol (30 microgram/kg--1 mg/kg) prolonged the atrioventricular (A-V) conduction time and functional refractory period of the A-V conduction system (FRP) by blockade of the existing tone of the sympathetic nerves to the heart. The prolongation of the two parameters by the non-specific depressant action of propranolol was evident only at 3 mg/kg. Propranolol (3--30 microgram/kg) shortened the A-V conduction time in the heart deprived of the vagal and sympathetic tone, suggesting some sort of sympathomimetic effect. Pindolol in a wide range of doses (0.3--300 microgram/kg) exerted virtually no effect on the A-V conduction time and FRP, and its non-specific depressant action was apparent only at 3 mg/kg. Carteolol slightly prolonged the A-V conduction time and FRP only in low doses (1--10 microgram/kg), and in high doses (30 microgram/kg--1 mg/kg) it shortened the two parameters, reflecting its predominant sympathomimetic action.

Animals↗