Preparation of isolated cells from rat heart

Summary Suspensions of isolated cells from rat heart were prepared and the data for viability and yield are given. Glucose uptake by the cells was mediated by a carrier system.The technical assistance of Mr.E. T. Potter, Mr.K. D. Patel and Mr.M. Griffin is gratefully acknowledged.     

Effect of temperature on the activity of AMP-deaminase from rat heart

Summary In the presence of 1 mM ATP, the plots of Michaelis dependence of the reaction catalysed by AMP-deaminase from rat heart were hyperbolic at all temperatures between 10 and 40°C. Calculation of the energy of activation for ATP-activated enzyme and of the enzyme-substrate complex formation is presented.     

Peroxidative activity of hemepeptides from horse heart cytochromec

Résumé L'hémoundécapeptide (HUP) a été préparé par digestion pepsique du cytochromec qui a été extrait et purifié à partir du cur de cheval. L'hémooctapeptide (HOP) a été obtenu par digestion trypsique de l'HUP. L'un et l'autre ont donné des produits homogènes par chromatographie sur colonne et sur papier, par électrophorèse sur papier à différents pH et par analyse des acides aminés. On a effectué une analyse spectrométrique de HUP et HOP et déterminé leur activité peroxydasique dans diverses conditions. Ces 2 composés n'ont pas montré d'activité catalasique.

---

---

This paper is based on a thesis submitted byY. Y. Hsiao in partial fulfillment for the degree of Master of Science at Utah State University.     

Effect of temperature on the activity of AMP-deaminase from rat heart.

In the presence of 1 mM ATP, the plots of Michaelis dependence of the reaction catalysed by AMP-deaminase from rat heart were hyperbolic at all temperatures between 10 and 40 degrees C. Calculation of the energy of activation for ATP-activated enzyme and of the enzyme-substrate complex formation is presented.     

Isolation of crystalline aldosterone from the urine of patients with congestive heart failure

Zusammenfassung Der Natrium-retinierende Faktor aus dem Urin zweier Patienten mit Stauungs-Herzfehlern wurde in kristallisierter Form isoliert und mit Aldosteron identifiziert.

---

---

Communication No. 137 On Steroids. No. 136 compareA. Wettstein, Exper.11, 465 (1955).     

Formation of norepinephrine from tyrosine in isolated rabbit heart

Zusammenfassung Die Bildung des Noradrenalins aus Tyrosin konnte im isolierten Kaninchenherzen nachgewiesen werden. Die Reaktion scheint für Tyrosin spezifisch zu sein. Aus Tyramin wurde kein Noradrenalin gebildet. Ebenfalls wurde die Umwandlung von Tyramin in Norsynephrin und von Dopamin in Noradrenalin nachgewiesen.     

Ouabain potentiation of Ca release from fragmented cardiac sarcoplasmic reticulum from isolated cat heart

Summary The present study was performed to determine the effect of ouabain on Ca release from fragmented sarcoplasmic reticulum (FSR) isolated from cat cardiac muscles. The results clearly demonstrate that ouabain potentiates the Ca release from FSR by changing the ionic environment.     

Improved diffraction patterns from isolated heart muscle with infrared light

Summary Diffraction measurement of myofilament overlap can be made with greater resolution or extended to thicker heart muscle preparations by using light of a near IR wavelength.Supported in part by National Heart and Lung Institute, grant 5 R01 HL 18668-02.I wish to thank Dr E. H. Sonnenblick for support, Dr M. Kawai for advice, and Mr Andrew Hopkins, Jr, for technical assistance.     

Ouabain potentiation of Ca release from fragmented cardiac sarcoplasmic reticulum from isolated cat heart.

The present study was performed to determine the effect of ouabain on Ca release from fragmented sarcoplasmic reticulum (FSR) isolated from cat cardiac muscles. The results clearly demonstrate that ouabain potentiates the Ca release from FSR by changing the ionic environment.     

Human heart disease: lessons from human pluripotent stem cell-derived cardiomyocytes

Technical advances in generating and phenotyping cardiomyocytes from human pluripotent stem cells (hPSC-CMs) are now driving their wider acceptance as in vitro models to understand human heart disease and discover therapeutic targets that may lead to new compounds for clinical use. Current literature clearly shows that hPSC-CMs recapitulate many molecular, cellular, and functional aspects of human heart pathophysiology and their responses to cardioactive drugs. Here, we provide a comprehensive overview of hPSC-CMs models that have been described to date and highlight their most recent and remarkable contributions to research on cardiovascular diseases and disorders with cardiac traits. We conclude discussing immediate challenges, limitations, and emerging solutions.     

Role of nitric oxide in the functional response to ischemia-reperfusion of heart mitochondria from hyperthyroid rats

We investigated the role of nitric oxide (NO) in the mitochondrial derangement associated with the functional response to ischemia-reperfusion of hyperthyroid rat hearts. Mitochondria were isolated at 3000 g from hearts subjected to ischemia-reperfusion, with or without N-nitro-L-arginine (L-NNA, an NO synthase inhibitor). During reperfusion, hyperthyroid hearts displayed tachycardia and low functional recovery. Their mitochondria exhibited O₂ consumption similar to euthyroid controls, while H₂O₂ production, hydroperoxide, protein-bound carbonyl and nitrotyrosine levels, and susceptibility to swelling were higher. L-NNA blocked the reperfusion tachycardic response and increased inotropic recovery in hyperthyroid hearts. L-NNA decreased mitochondrial H₂O₂ production and oxidative damage, and increased respiration and tolerance to swelling. Such effects were higher in hyperthyroid preparations. These results confirm the role of mitochondria in ischemia-reperfusion damage, and strongly suggest that NO overproduction is involved in the high mitochondrial dysfunction and the low recovery of hyperthyroid hearts from ischemia-reperfusion. L-NNA also decreased protein content and cytochrome oxidase activity of a mitochondrial fraction isolated at 8000 g. This and previous results suggest that the above fraction contains, together with light mitochondria, damaged mitochondria coming from the heaviest fraction, which has the highest cytochrome oxidase activity and capacity to produce H₂O₂. Therefore, we propose that the high mitochondrial susceptibility to swelling, favoring mitochondrial population purification from H₂O₂-overproducing mitochondria, limits hyperthyroid heart oxidative stress.Received 24 March 2004; received after revision 9 June 2004; accepted 5 July 2004