THE WATER AND ELECTROLYTE METABOLISM OF RAT DIAPHRAGM IN VITRO

1956 ◽  
Vol 34 (5) ◽  
pp. 1069-1083 ◽  
Author(s):  
R. H. Rixon ◽  
J. A. F. Stevenson
Keyword(s):  
Intracellular Water ◽  
Diaphragm Muscle ◽  
Optimal Conditions ◽  
Rat Diaphragm ◽  
Concentration Gradients ◽  
Hypoxic Conditions ◽  
Diaphragm In Vitro ◽  
Sodium And Potassium

The distribution of water and of sodium and potassium between the cell and synthetic environments has been studied in rat diaphragm muscle. It has been found that: (1) the amount of intracellular water is markedly increased at 0 °C. in oxygen and at 37 °C. in nitrogen compared to that of tissue at 37 °C. in oxygen, in media up to 0.75 osmolar; (2) optimal conditions of temperature and oxygen are necessary to prevent or reduce the uptake of water; (3) swelling at reduced temperatures and under hypoxic conditions is related to the oxygen uptake; (4) the loss of tissue solids during incubation does not have any significant effect on the calculation of the total tissue and intracellular water; (5) the concentration of total sodium and potassium in the tissue, in vivo and in vitro at optimal conditions is slightly in excess of that in the plasma water or incubating medium—this is believed not to represent an active hypertonicity; (6) concomitant with the uptake of water there are marked redistributions of sodium and potassium, the gain of sodium being greater than the loss of potassium. It is concluded that the swelling of tissue cells under conditions that inhibit oxidative metabolism is primarily due to the redistribution of electrolytes and that the natural distribution of water in muscle is determined by active maintenance of the concentration gradients of sodium and potassium across the cell membrane.

THE WATER AND ELECTROLYTE METABOLISM OF RAT DIAPHRAGM IN VITRO

1956 ◽  
Vol 34 (1) ◽  
pp. 1069-1083 ◽  
Author(s):  
R. H. Rixon ◽  
J. A. F. Stevenson
Keyword(s):  
Intracellular Water ◽  
Diaphragm Muscle ◽  
Optimal Conditions ◽  
Rat Diaphragm ◽  
Concentration Gradients ◽  
Hypoxic Conditions ◽  
Diaphragm In Vitro ◽  
Sodium And Potassium

The distribution of water and of sodium and potassium between the cell and synthetic environments has been studied in rat diaphragm muscle. It has been found that: (1) the amount of intracellular water is markedly increased at 0 °C. in oxygen and at 37 °C. in nitrogen compared to that of tissue at 37 °C. in oxygen, in media up to 0.75 osmolar; (2) optimal conditions of temperature and oxygen are necessary to prevent or reduce the uptake of water; (3) swelling at reduced temperatures and under hypoxic conditions is related to the oxygen uptake; (4) the loss of tissue solids during incubation does not have any significant effect on the calculation of the total tissue and intracellular water; (5) the concentration of total sodium and potassium in the tissue, in vivo and in vitro at optimal conditions is slightly in excess of that in the plasma water or incubating medium—this is believed not to represent an active hypertonicity; (6) concomitant with the uptake of water there are marked redistributions of sodium and potassium, the gain of sodium being greater than the loss of potassium. It is concluded that the swelling of tissue cells under conditions that inhibit oxidative metabolism is primarily due to the redistribution of electrolytes and that the natural distribution of water in muscle is determined by active maintenance of the concentration gradients of sodium and potassium across the cell membrane.

Theophylline minimally alters contractile properties of canine diaphragm in vitro

1990 ◽  
Vol 69 (4) ◽  
pp. 1390-1396 ◽  
Author(s):  
E. Derom ◽  
S. Janssens ◽  
V. De Bock ◽  
M. Decramer
Keyword(s):  
High Frequency ◽  
Force Production ◽  
Contractile Properties ◽  
Diaphragm Muscle ◽  
Muscle Bundle ◽  
Time To Peak ◽  
Diaphragm In Vitro ◽  
Tetanic Tension

We examined the effects of theophylline on contractile properties and high-frequency fatigue of canine diaphragm in vitro. Eighteen diaphragm muscle bundles were obtained from 10 anesthetized dogs and equilibrated in oxygenated Krebs solution to 100, 200, or 300 mg/l theophylline. These bundles were compared with 18 matched control bundles from the contralateral hemidiaphragm. No statistically significant differences in twitch tension, tetanic tension, twitch-to-tetanus ratio, time to peak tension, or half-relaxation time were observed. Concentrations of 300 mg/l theophylline, however, significantly (P less than 0.05) increased force production at 10 Hz by 32%. A similar tendency was present at lower concentrations and exhibited a clear dose-response behavior. High-frequency fatigue was similar in control and theophylline-treated bundles. We conclude that supratherapeutic in vitro concentrations of theophylline do not increase maximal tetanic tension and do not protect against muscle fatigue but potentiate relative force production at low stimulation frequencies. This relatively small effect cannot be explained by poor diffusion of the drug in the muscle bundle, because theophylline concentrations in the muscle bath and in the muscle bundle were virtually identical. Moreover, it remains unclear whether this potentially beneficial effect can be achieved at in vivo attainable serum concentrations.

Utilization of free fatty acids by diaphragm in vitro

1962 ◽  
Vol 203 (2) ◽  
pp. 311-315 ◽  
Author(s):  
P. T. Bodel ◽  
D. Rubinstein ◽  
E. E. McGarry ◽  
J. C. Beck
Keyword(s):  
Fatty Acids ◽  
Growth Hormone ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Free Fatty Acids ◽  
Gastrocnemius Muscle ◽  
Rat Diaphragm ◽  
Diaphragm In Vitro

Human and rat diaphragm and rat gastrocnemius muscle oxidize and esterify palmitate-1-C14. Incorporation of C14 was found to be in proportion to the palmitate present in the medium over a range of concentrations from 0.8 to 2.9 µEq/ml. Fasting increased C14O2 production but had no effect on esterification. Iodoacetate or an atmosphere of nitrogen inhibited esterification of palmitate but increased the amount of free fatty acid in the tissue. Insulin increased esterification, and this was enhanced by the addition of glucose. Glucose and insulin exerted a sparing action on the oxidation of glycerides by a tissue previously charged with palmitate-1-C14. Growth hormone administered in vivo over a period of 1 week or in vitro during incubation had no effect on esterification or metabolism of palmitate-1-C14.

scholarly journals Comparison of some metabolic parameters in the perfused and the incubated rat diaphragm muscle with diaphragm muscle in vivo

1971 ◽  
Vol 125 (1) ◽  
pp. 93-96 ◽  
Author(s):  
K. A. Rookledge
Keyword(s):  
Oxidative Phosphorylation ◽  
Water Content ◽  
Lactate Production ◽  
Metabolic Parameters ◽  
Diaphragm Muscle ◽  
Rat Diaphragm ◽  
Free Glucose ◽  
Hexose Phosphates

1. A method is described for perfusing the rat diaphragm muscle. 2. The following parameters were compared in both perfused and non-perfused incubated preparations: water content, sorbitol space, rate of lactate production, and the concentrations of tissue glucose, pyruvate, lactate, hexose phosphate intermediates, ATP and AMP. No significant differences were found. 3. Significant differences, however, were found on comparison of the tissue kept in vitro with the tissue in vivo. Immediately after removal of the tissue from the animal, the concentrations of the hexose phosphates and ATP were found to be much higher than after incubation or perfusion, and the concentrations of free glucose and of AMP were much lower, possibly indicating that the capacity for oxidative phosphorylation of glucose is impaired in vitro because of hypoxia.

Action of epinephrine on muscle glucose uptake depending on Ca++ and phosphate

1965 ◽  
Vol 209 (2) ◽  
pp. 359-364 ◽  
Author(s):  
Michio Ui
Keyword(s):  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Inorganic Phosphate ◽  
Glucose Utilization ◽  
Rat Diaphragm ◽  
Muscle Tissues ◽  
Ph Level ◽  
Diaphragm In Vitro

Studies have been made of the involvement of inorganic phosphate (Pi) and Ca++ in the mechanism by which epinephrine-induced inhibition of muscle glucose utilization was abolished during either alkalosis in vivo or incubation of the isolated rat diaphragm in vitro at a higher pH level. An increase in the concentration of Pi in muscle tissues was closely associated with prevention of the inhibitory action of epinephrine on glucose uptake. The interrelationship of Ca++ and Pi in aqueous solutions, and the additional observations that glucose uptake by rat diaphragm was accelerated in anaerobiosis only in the absence of Ca++, indicate a significance of Ca++ in muscle glucose metabolism. Assay of hexokinase activity in cell-free muscle preparations revealed that the inhibition of the enzyme activity by glucose 6-phosphate was profoundly influenced by the presence of Ca++ and Pi and was dependent on the concentration of ATP. It is suggested that Ca++ may provide the primary point of influence of epinephrine on glucose metabolism of the muscle.

scholarly journals Survival and Proliferation under Severely Hypoxic Microenvironments Using Cell-Laden Oxygenating Hydrogels

2021 ◽  
Vol 12 (2) ◽  
pp. 30
Author(s):  
Shabir Hassan ◽  
Berivan Cecen ◽  
Ramon Peña-Garcia ◽  
Fernanda Roberta Marciano ◽  
Amir K. Miri ◽  
...  
Keyword(s):  
Prolonged Release ◽  
Therapeutic Approaches ◽  
Encapsulated Cells ◽  
Hypoxic Conditions ◽  
Skeletal Myoblasts ◽  
Artificial Tissue ◽  
Delivery Platform ◽  
Living Tissues

Different strategies have been employed to provide adequate nutrients for engineered living tissues. These have mainly revolved around providing oxygen to alleviate the effects of chronic hypoxia or anoxia that result in necrosis or weak neovascularization, leading to failure of artificial tissue implants and hence poor clinical outcome. While different biomaterials have been used as oxygen generators for in vitro as well as in vivo applications, certain problems have hampered their wide application. Among these are the generation and the rate at which oxygen is produced together with the production of the reaction intermediates in the form of reactive oxygen species (ROS). Both these factors can be detrimental for cell survival and can severely affect the outcome of such studies. Here we present calcium peroxide (CPO) encapsulated in polycaprolactone as oxygen releasing microparticles (OMPs). While CPO releases oxygen upon hydrolysis, PCL encapsulation ensures that hydrolysis takes place slowly, thereby sustaining prolonged release of oxygen without the stress the bulk release can endow on the encapsulated cells. We used gelatin methacryloyl (GelMA) hydrogels containing these OMPs to stimulate survival and proliferation of encapsulated skeletal myoblasts and optimized the OMP concentration for sustained oxygen delivery over more than a week. The oxygen releasing and delivery platform described in this study opens up opportunities for cell-based therapeutic approaches to treat diseases resulting from ischemic conditions and enhance survival of implants under severe hypoxic conditions for successful clinical translation.

scholarly journals Action of Insulin on Transport of l-Alanine into Rat Diaphragm in Vitro

1973 ◽  
Vol 248 (18) ◽  
pp. 6450-6455
Author(s):  
Thomas R. Riggs ◽  
K. Janet McKirahan
Keyword(s):  
Rat Diaphragm ◽  
Diaphragm In Vitro

scholarly journals Dephosphorylation of Nucleoside Triphosphates by Rat Diaphragm in vitro.

1957 ◽  
Vol 11 ◽  
pp. 1078-1079 ◽  
Author(s):  
Aa. Rye Alertsen ◽  
O. Walaas ◽  
E. Walaas ◽  
K. E. Almin ◽  
Arne Magnéli ◽  
...  
Keyword(s):  
Rat Diaphragm ◽  
Nucleoside Triphosphates ◽  
Diaphragm In Vitro
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