Terrell L. Rich

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Null point titration techniques have been developed for measurements of cytosolic free Mg2+ in isolated cells and matrix free Mg2+ in isolated mitochondria using antipyrylazo III as a spectrophotometric Mg2+ indicator. A cytosolic free Mg2+ of 0.37 +/- 0.02 mM was obtained with hepatocytes. This represented about 6% of the total cytosolic magnesium content(More)
The purpose of this study was to define further the basis of control of myocardial membrane permeability by further examination of the "calcium paradox." To this end, the protective effect of hypothermia and addition of micromolar amounts of divalent cations during the Ca-free perfusion period were studied. Damage during Ca++ repletion to the isolated(More)
The effects of respiratory and metabolic acidosis on myocardial contractility and energy production have been investigated in the perfused rat heart. Respiratory acidosis, produced by increasing the Pco2 , caused an 80% inhibition of pressure development at pH 6.7. When artificial buffers (plus HCI) were used in place of bicarbonate and CO2, only a 30%(More)
Calcium (Ca) exchange was studied under various perfusion conditions in monolayer myocardial culture and in the interventricular septum of the rabbit. In cultured cells perfused in HEPES buffered medium or in 10 mM phosphate (Pi), pH less than 7.2, 10 mM caffeine produced no change in 45Ca uptake rate. By contrast, increase of pH to 7.35 in the presence of(More)
Application of a new rapid perfusion (up to 4.8 ml/s) technique to 45Ca-labeled ventricular cells from adult rat heart has defined a discrete intracellular calcium (Ca) compartment with the following characteristics: 1) its exchange is absolutely dependent on operation of the Na-Ca exchanger, i.e., its isotopic content remains constant during washout in the(More)
It has been shown by Chizzonite and Zak (Science 213:1508-1511, 1981) that rat hearts perfused with calcium (Ca)-free medium exhibit an age-dependent response to the Ca paradox. Below 6 days the hearts were insensitive to Ca depletion. By 15 days the hearts developed a sensitivity to Ca depletion monitored by the development of contracture and release of(More)
The relationships among isometric tension development, the oxidation-reduction states of pyridine nucleotides and cytochrome c, and the oxygenation state of myoglobin have been assessed using the arterially perfused rabbit interventricular septum under different conditions of contraction rate, perfusate [Ca2+] and pH, catecholamine stress, and hypoxia.(More)
Interventricular septa and semimembranosus accessorius muscles (SMA) from the guinea pig and frog gastrocnemius (FG) muscles were vascularly perfused and isolated for mechanical and radioisotope flux measurements. Since calcium deprivation causes progressive electrical inexcitability, 100 muM La was included in all calcium-free solutions (0-Ca, 100-La) to(More)
The ultrastructure of the Ca-depleted myocardial sarcolemma (via Ca-free and Ca-free plus EGTA perfusion at 28°C and 37°C) was studied in the vascularly perfused interventricular septum of the rabbit. Thin-section and freeze-fracture electron microscopy was used. Two major structural defects in the sarcolemma were found. (1) Ninety percent of the(More)