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Biomedical subjects

I R Cameron

Publications and source records attributed to I R Cameron.

At least 73 records · Page 4Linked to original sources
PubMed1975

ECS, intracellular pH, and electrolytes of cardiac and skeletal muscle.

The extracellular space (ECS) of muscle from each ventricle of the heart (RV and LV), the atria, diaphragm, and quadriceps was estimated in the anesthetized rabbit from the distribution volumes of [14C]insulin, [14C]sucrose, [51Cr]EDTA, and C1--. Whole-tissue electrolytes were measured and intracellular electrolytes calculated. The ECS of the tissues varied, increasing in the order quadriceps less than LV less than RV less than atria. The volume of distribution of [14C]inulin was always less than that of either [14C]sucrose or [51Cr]EDTA which agreed closely, whereas that of C1-- was always greater. There was no difference in intracellular K+ in muscle from each of the cardiac chambers, whereas intracellular Na+ and C1-- varied, increasing in the order quadriceps less than LV less than RV less than atria. Intracellular pH, measured with [14C]DMO did not differ in any of the tissues studied. It is concluded that, in vivo, the estimated ECS incardiac muscle is lower than that reported in vitro, that [51Cr]EDTA is a satisfactory ECS marker, and that differences in intracellular Na+ and C1-- but not K+ or pH exist between muscle from the cardiac chambers.

Animals↗
PubMed1975

Intracellular pH and K+ of cardiac and skeletal muscle in acidosis and alkalosis.

The effects of a metabolic and respiratory acidosis and alkalosis on intracellular pH (pHi) and K+ have been compared in cardiac and skeletal muscle from the anesthetized rabbit. The extracellular space and pHi were calculated from the distribution volumes of [51Cr] EDTA and [14C]DMO, respectively. When pHe was varied by altering PCO2, the slope of the line relating pHi to the extracellular pH (pHe) was greater (P less than 0.05--0.001) than that obtained during metabolic changes of pHe in right and left ventricles, atria, diaphragm, and quadriceps. During metabolic acidosis and alkalosis, the slope of pHi/pHe line did not vary between tissues. During respiratory acidosis, there was no difference in slope between cardiac tissues, but it was less in left ventricle than quadriceps (P less than 0.001). In left ventricle intracellular K+ increased in a metabolic (P less than 0.05) or respiratory acidosis (P less than 0.02), whereas in diaphragm it decreased (P less than 0.02). Intracellular K+ correlated with pHe and pHE-PHi. Changes in pHi but not intracellular K+ could explain known differences in myocardial function in respiratory and metabolic acidosis.

Acidosis↗
PubMed1970

The effect on respiration of abrupt changes in carotid artery pH and PCO2 in the cat.

1. An in vivo pH monitoring technique was used to assess changes in pH, and by inference changes in P(CO2), in the carotid artery of anaesthetized cats. The changes in carotid artery pH and respiration following abrupt injections of various acids into the carotid artery or aorta were investigated.2. Injections of saline equilibrated with 100% CO(2), timed to produce changes at the carotid body chemoreceptors during early inspiration caused an increase in the tidal volume of that breath. The amplitude and rate of change of the pH changes so produced were comparable with those of the oscillations in pH produced by respiration itself.3. The respiratory responses to injection of saline equilibrated with 100% CO(2) occurred whether the animal was breathing air or 100% O(2).4. Injections of lactic or hydrochloric acid were without an effect on respiration, except when pH changes larger than 0.1 pH unit were produced. A NaHCO(3) solution equilibrated with 30% CO(2) stimulated respiration, even though the solution was alkaline to the cat's arterial blood and induced an alkaline change in arterial pH.5. Infiltration of the carotid sinus nerve area with procaine temporarily abolished the respiratory response to injections of saline equilibrated with 100% CO(2).

Animals↗