Biomedical subjects

M J Keyl

Publications and source records attributed to M J Keyl.

18 recordsLinked to original sources

PubMed1987

The effect of plasma volume expansion on the response to carotid occlusion in the non-human primate.

The purpose of this study was to investigate the effects of plasma volume expansion on the cardiac and peripheral components of the baroreceptor reflex. Nine male Rhesus monkeys were chronically instrumented to measure arterial pressure and aortic blood flow. The aortic arch was denervated at the time of surgery. Bilateral carotid artery occlusion (BCO) was used to elicit the carotid sinus reflex both before and after 25% plasma volume expansion with an iso-osmotic dextran solution. The BCO elicited significant increases in heart rate (HR, 29.8 +/- 5.3 bpm) mean arterial pressure (MAP, 55.0 +/- 8.2 mm Hg) and total peripheral resistance (TPR, 0.076 +/- 0.01 mm Hg/ml/min) coupled with a significant reduction in mean aortic flow (AF, -246.9 +/- 55.3 ml/min) and stroke volume (SV, -2.86 +/- 0.36 ml). Volume expansion significantly attenuated the HR (15.2 +/- 5.8 bpm), MAP (30.4 +/- 4.4 mm Hg) and TPR (0.036 +/- 0.006 mm Hg/ml/min) response to carotid sinus hypotension. The changes in mean AF and SV elicited by BCO, however, were not significantly different between the control and volume expansion conditions. These data suggest that plasma volume expansion significantly attenuates the baroreceptor reflex control of circulation with a similar reduction in both the peripheral resistance and heart rate components of the response.

Anesthesia↗

PubMed1983

Hormonal and renal response to plasma volume expansion in the primate Macaca mulatta.

The purpose of this study was to investigate the hormonal and renal response to plasma volume expansion in the ketamine-anesthetized rhesus monkey. The blood volume was determined in nine animals and found to be 6% of the body weight. Six monkeys received isoncotic isotonic fluid amounting to 25% of the blood volume. Plasma volume expansion led to significant decrease in the plasma concentrations of antidiuretic hormone (46.7%) and aldosterone (78.4%) as well as plasma renin activity (50.0%). The mean arterial pressure, plasma osmolality, and plasma concentrations of Na+ and K+ were unaffected by plasma volume expansion. However, renal plasma flow, glomerular filtration rate, the excretion of Na+ and K+, and urine flow increased. It was concluded that, in the ketamine-anesthetized rhesus monkey, circulating hormones contribute to blood volume homeostasis presumably through a neural mechanism similar to that observed in dogs and humans.

Aldosterone↗

PubMed1981

Constituents of lymph from the non-secreting stomach of the dog.

Gastric lymph collected from the non-secreting stomach of anesthetized dogs contained glucose, Na+, K+ and creatine phosphokinase in concentrations that were similar to those in arterial and gastric venous plasma. Gastric lymph contained greater concentrations of pyruvate and lactate than in either arterial or gastric venous blood. Gastric lymph contained a high concentration of total protein similar to that in simultaneously collected hepatic lymph. Gastric lymph was collected before and after the pylorus was ligated and the stomach distended with air. These procedures were used in another study in which total protein in gastric lymph was reported to be much lower than found in the present study. The lymph to plasma ratio for protein was decreased from 0.85 +/- .04 to 0.69 +/- .04. Pyloric ligation alone caused no change in lymph protein concentration.

Animals↗

PubMed1980

Comparison of renal and cardiac lymph constitutents.

The concentration of various substances were measured in renal and cardiac lymph and arterial and venous plasma to determine if lymph constituents might indicate events occurring at the cellular level in these two organs. The study utilized anesthetized dogs. Magnesium, calcium, pyruvate and glucose concentrations were similar in the four fluids. Cardiac lymph contained significantly higher concentrations of creatine phosphokinase, lactic dehydrogenase and lactate. Renal lymph contained lower concentrations of zinc and protein while both renal and cardiac lymph contained less copper than arterial plasma. Venous plasma contained more copper than the other fluids. It is concluded that lymph composition reflects events occurring in the cells, especially for substances that are not readily diffusable through blood capillary endothelium.

Animals↗

PubMed1978

Effect of endotoxin on glucose uptake by the isolated forelimb of the dog.

Recent research has demonstrated that an increase in glucose utilization by skeletal muscle occurs in hemorrhagic shock. It is conceivable that the hypoglycemia of gram-negative septic shock is, in part, due to increased glucose utilization by peripheral tissues. The hypothesis tested in this study was that there is an increase in glucose uptake by the isolated innervated and/or denervated forelimb of the dog subjected to endotoxin shock. Results indicate that endotoxin does not affect a net increase of glucose uptake by the isolated forelimb. No increase in uptake occurred when blood glucose concentration was normal. However, when endotoxin hypotension induced a significant hyperglycemia or when arterial glucose concentration was elevated by glucose administration an apparent increase in forelimb glucose uptake occurred. It is concluded that endotoxin does not increase the uptake of glucose by skin and muscle except that it causes hyperglycemia secondary to increased sympathoadrenal discharge in the shock state. Thus, if the dog becomes sufficiently hyperglycemic, an apparent increase in glucose uptake occurs, probably because of accumulation of glucose in the interstititial space of skin and muscle.

Animals↗

PubMed1978

Lymph and intrarenal venous blood as indicators of canine renal cortical function.

Samplings of canine capsular and hilar lymph, and intrarenal venous blood were investigated as in vivo techniques for detecting renal cortical function in control and NH4Cl pretreated anesthetized animals. The glucose concentration of capsular, but not hilar, lymph was indicative of cortical drainage in both groups. When lymph flow was increased by elevating renal venous pressure, capsular lymph glucose concentration reflected cortical function only in the NH4Cl animals. The glucose concentration of intrarenal venous blood indicated cortical drainage in both the control and NH4Cl animals but the cortical function of a high para-aminohippuric acid extraction was only detectable in the NH4Cl group. Conclusions are that sampling of capsular lymph and intrarenal venous blood may prove to be useful techniques for studying certain in vivo cortical functions but the intrarenal venous technique is less sensitive than capsular lymph collection.

Administration, Oral↗

PubMed1974