Triphasic vascular effects of thiol compounds and their oxidized forms on dog coronary arteries

The vascular effects of 2-mercaptoethanol, cysteamine, L-cysteine, glutathione (GSH), cystamine and oxidized GSH (GSSG) on the isometric tension of isolated dog coronary arterial strips were examined, and these effects were compared with the triphasic response induced by dithiothreitol (DTT); a rapid and weak contraction (phase A), an intervening slow relaxation (phase B) and a slowly-developing strong contraction (phase C) which we previously reported. The responses of the arteries induced by 2-mercaptoethanol, cysteamine and L-cysteine consisted of phases A, B and C. The order of contractile potency (ED₅₀ of phase C) was DTTL-cysteine>2-mercaptoethanolcysteamine, while the order of relaxant potency (ED₅₀ of phase B) was DTT>cysteamine2-mercaptoethanol. GSSG and cystamine mainly produced relaxation, which corresponded to phase B. The phase C contraction was specific to the reduced forms of thiols, except for GSH, which produced only relaxation. The participation of endothelial cells was not essential for the contracting or relaxing effects of the thiol compounds. The phase C contraction was depressed by W-7, a calmodulin antagonist, while phase A was not. Therefore calmodulin-dependent protein kinases may participate in phase C, not in phase A.     

Dependence of the contractility of coronary muscle on substances favouring contraction and relaxation

Zusammenfassung Es werden die Besonderheiten der am isolierten Koronargefäss von Rind und Pferd nach elektrischer Reizung, Verabreichung von Adrenalin oder Kalium registrierten Mechanogramme beschrieben. Es wird darauf hingewiesen, dass die Kontraktilität der Muskelzellen des Rinderkoronargefässes von zwei Stoffen abhängig ist, wovon der eine die Kontraktion und der andere die Erschlaffung fördert.

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I thank the Schweizerischer Nationalfonds für wissenschaftliche Forschung for help.     

Acidic glycosaminoglycans in human coronary arteries,with special reference to the presence of heparin or related glucosaminoglycan

Summary Acidic glycosaminoglycans (AGAG) in 3 branches of the human coronary artery were enzymatically analyzed. The main AGAG were heparan sulfate, chondroitin sulfates and dermatan sulfate. The yield of AGAG decreased in the order of left, right and peripheral branches. Heparin or a related glucosaminoglycan were dominant in the peripheral branch.The study was supported, in part, by grants-in-aid for scientific research from the Ministry of Education, Science and Culture of Japan, and the Adult Disease Clinic Memorial Foundation, Tokyo. Thanks aee due to Dr M. Okudaira and Dr R. Kono for collecting specimens.     

Oxatomide,a new orally active drug which inhibits both the release and the effects of allergic mediators

Summary Oxatomide is a new potent inhibitor of anaphylactic and allergic reactions. After oral administration, the compound both inhibits the release of endogenous histamine and prevents the effects of exogenous histamine, at comparable doses. The combination of these effects appears to be the basis of the effectiveness of oxatomide in allergic reactions and may lead to clinical applications different from classical antihistaminics and from cromoglycate.     

Oxatomide, a new orally active drug which inhibits both the release and the effects of allergic mediators.

Oxatomide is a new potent inhibitor of anaphylactic and allergic reactions. After oral administration, the compound both inhibits the release of endogenous histamine and prevents the effects of exogensous histamine, at comparable doses. The combination of these effects appears to be the basis of the effectiveness of oxatomide in allergic reactions and may lead to clinical application different from classical antihistaminics and from cromoglycate.     

Elastase,collagenase and the radial elastic properties of arteries

Summary Studies were performed on 203 pairs of dog carotid arteries subjected to unidirectional radial compression. Treatment with 80 U/ml purified elastase for 90 min decreased radial stress, but treatment with 640 U/ml collagenase for 90 min did not. These data suggest that elastin, but not collagen, contributes to wall resistance to radial compression.     

Elastase, collagenase and the radial elastic properties of arteries

Studies were performed on 203 pairs of dog carotid arteries subjected to unidirectional radial compression. Treatment with 80 U/ml purified elastase for 90 min decreased radial stress, but treatment with 640 U/ml collagenase for 90 min did not. These data suggest that elastin, but not collagen, contributes to wall resistance to radial compression.     

Special cases,composition of causes,and the complexity of nature

It is often held by philosophers of science that special, idealized situations are prior to complex cases in several senses: equations for complex cases are derived from those for special cases by “composing” special case equations; behavior in complex cases is explained in terms of behavior in special cases; one learns the true nature of a property in the special case where it is allowed to work in isolation. In this paper, I argue that a strand of non-equilibrium thermodynamics which attempts to go beyond the limitations of classical non-equilibrium thermodynamics adheres to something that is the reverse of this picture. Thus, the legitimacy (or lack thereof) of this picture lies very near to the heart of foundational issues in non-equilibrium thermodynamics.     

Unification, explanation, and the composition of causes in Newtonian mechanics

William Whewell's philosophy of scientific discovery is applied to the problem of understanding the nature of unification and explanation by the composition of causes in Newtonian mechanics. The essay attempts to demonstrate: (1) the sense in which ‘approximate’ laws (e.g. Kepler's laws of planetary motion) successfully refer to real physical systems rather than to (fictitious) idealizations of them; (2) why good theoretical constructs are not badly underdetermined by observation; and why, in particular, Newtonian forces are not conventional and (3) how empiricist arguments against the existence of component causes, and against the veracity of the fundamental laws, are flawed.     

Comparison of the effects of illumination on the melanophores of intact and eyestalkless fiddler crabs,Uca pugilator,and inhibition of the primary response by cytochalasin B

Summary Approximately 100 times more illumination is required to produce pigment dispersion in the melanophores of eyestalkless fiddler crabs (Uca pugilator) than in the melanophores of intact crabs. The pigment in melanophores of isolated legs will normally disperse in response to irradiation, but this response is inhibited by cytochalasin B.This investigation was supported by a Faculty Research Grant from Western Kentucky University toT. P. Coohill and by Grant No. GB-27497 toM. Fingerman from the National Science Foundation.     

The effects of an indole derivative 6-(2′-Aminopropyl indole) on the general and coronary haemodynamics of the intact dog

Zusammenfassung Bei mehreren Experimenten an Hunden mit Indolderivaten (MR 689 Sandoz) hat sich erwiesen, dass der vaskuläre Blutdruck, das Minutenvolumen, die Herzarbeit, der koronare Blutkreislauf und der O₂-Verbrauch sich erhöhte bei Erhaltung der Herzleistung.     

Comparison of the effects of illumination on the melanophores of intact and eyestalkless fiddler crabs, Uca pugilator, and inhibition of the primary response by cytochalasin B.

Approximately 100 times more illumination is required to produce pigment dispersion in the melanophores of eyestalkless fiddler crabs (Uca pugilator) than in the melanophores of intact crabs. The pigment in melanophores of isolated legs will normally disperse in response to irradiation, but this response is inhibited by cytochalasin B.     

Identification of both fucosterol and isofucosterol in the siklworm,Bombyx mori

Summary Fucosterol and isofucosterol were identified in the silkworm,Bombyx mori.     

Behavloural effects of an antigonadotropin,of sexual hormones,and of psychopharmaka in the pumpkinseed sunfish,Lepomis gibbosus (Centrarchidae)

Zusammenfassung Ein synthetisches Antigonadotropin (Methallibur, I.C.I) hemmt das Sexual- und Nestbauverhalten von Sonnenbarsch-Männchen (Lepomis gibbosus). Testosteron hingegen steigert die Aggressivität, und Säuger-LH zudem noch die Sexualtendenz. Reserpin erhöht die Kampfstimmung; Chlorpromazin hemmt dagegen die Kampf- und Nestbaustimmung, nicht aber die Sexualtendenz.