Microdialysis in human skeletal muscle: effects of adding a colloid to the perfusate

2002 ◽  
Vol 92 (1) ◽  
pp. 385-393 ◽  
Author(s):  
K. Hamrin ◽  
H. Rosdahl ◽  
U. Ungerstedt ◽  
J. Henriksson
Keyword(s):  
Hydrostatic Pressure ◽  
Flow Rate ◽  
Glucose Concentration ◽  
Fluid Loss ◽  
Dialysis Membrane ◽  
Perfusion Flow ◽  
Perfusion Flow Rate ◽  
Perfused Catheters

Microdialysis catheters (CMA-60 with a polyamide dialysis membrane; 20,000-molecular wt cutoff) were either immersed in an external medium or were inserted in the quadriceps femoris muscle of healthy subjects, using perfusate with or without dextran 70. Varying the position of the outflow tubing induced changes in hydrostatic pressure. The sample volumes were significantly smaller in catheters perfused without a colloid compared with those perfused with a colloid [11–50% (in vitro) and 8–59% (in vivo) lower than in colloid-perfused catheters with the same position of the outflow tubing]. The sample volumes were also significantly smaller when the dialysis membrane was influenced by maximal hydrostatic pressure (above position) compared with minimal hydrostatic pressure (below position) [7–38% (in vitro) and 3–46% (in vivo) lower than in catheters in the below position with the same perfusion fluid]. In vivo, glucose concentration at a perfusion flow rate of 0.33 μl/min was higher when the catheters were perfused without a colloid [18–28% higher than in colloid-perfused catheters with the same position of the outflow tubing ( P < 0.001)] than with a colloid. A corresponding difference also tended to occur with lactate, glycerol, and urea. At 0.16 μl/min, the glucose concentration was the same irrespective of whether fluid loss had been counteracted by colloid inclusion or by lowering of outlet tubing. The mechanism behind the observed concentration difference is thought to be a higher effective perfusion flow rate when fluid loss is prevented at low-perfusion flows. This study shows that fluid imbalances can have important implications for microdialysis results at low-perfusion flow rates.

scholarly journals Perfusion-secretion relationships in the isolated elasmobranch rectal gland

1986 ◽  
Vol 125 (1) ◽  
pp. 373-384 ◽  
Author(s):  
T. J. Shuttleworth ◽  
J. L. Thompson
Keyword(s):  
Flow Rate ◽  
Control Level ◽  
Sodium Concentration ◽  
Secretion Rate ◽  
Rectal Gland ◽  
Concentration Difference ◽  
Perfusion Flow ◽  
Percentage Extraction ◽  
Perfusion Flow Rate

Perfusion and sodium secretion parameters were measured in the isolated rectal gland of Scyliorhinus canicula L. perfused at in vivo pressures, and the effect of stimulation of secretory activity by cyclic AMP and theophylline on these parameters was determined. Stimulation resulted in large increases in secretion flow rate, percentage extraction of sodium from the perfusing fluid, and arteriovenous sodium concentration difference, but did not affect perfusion flow rate or the sodium concentration of the secreted fluid. Reduction of perfusion flow rate to values below 65% of the control level, achieved by reducing perfusion pressure, produced a marked decline in sodium secretion--a process accompanied by increases in the percentage extraction of sodium and arteriovenous concentration difference of sodium, but again without any change in the sodium concentration of the secreted fluid. The in vivo consequences of these findings are discussed with reference to related findings for the avian nasal salt gland. The normal rate of secretion, its sodium concentration, and the nature of the dependence of secretion rate on perfusion flow below certain levels, were essentially unaffected by a reduction in the availability of oxygen to the gland by approximately 80%. It is concluded that the observed relationship between perfusion flow and sodium secretion rate in the stimulated gland is not related to oxygen availability, and hence that the primary underlying function of the synchronized secretion-related vasodilation seen in the gland is not to increase the supply of oxygen to the stimulated secretory tissue. We discuss possible reasons why this erroneous conclusion has been reached by other workers.

scholarly journals Staphylococcus aureus Serves as an Iron Source for Pseudomonas aeruginosa during In Vivo Coculture

2005 ◽  
Vol 187 (2) ◽  
pp. 554-566 ◽  
Author(s):  
Lauren M. Mashburn ◽  
Amy M. Jett ◽  
Darrin R. Akins ◽  
Marvin Whiteley
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Iron Acquisition ◽  
Low Oxygen ◽  
Dialysis Membrane ◽  
Opportunistic Human Pathogen ◽  
The Impact

ABSTRACT Pseudomonas aeruginosa is a gram-negative opportunistic human pathogen often infecting the lungs of individuals with the heritable disease cystic fibrosis and the peritoneum of individuals undergoing continuous ambulatory peritoneal dialysis. Often these infections are not caused by colonization with P. aeruginosa alone but instead by a consortium of pathogenic bacteria. Little is known about growth and persistence of P. aeruginosa in vivo, and less is known about the impact of coinfecting bacteria on P. aeruginosa pathogenesis and physiology. In this study, a rat dialysis membrane peritoneal model was used to evaluate the in vivo transcriptome of P. aeruginosa in monoculture and in coculture with Staphylococcus aureus. Monoculture results indicate that approximately 5% of all P. aeruginosa genes are differentially regulated during growth in vivo compared to in vitro controls. Included in this analysis are genes important for iron acquisition and growth in low-oxygen environments. The presence of S. aureus caused decreased transcription of P. aeruginosa iron-regulated genes during in vivo coculture, indicating that the presence of S. aureus increases usable iron for P. aeruginosa in this environment. We propose a model where P. aeruginosa lyses S. aureus and uses released iron for growth in low-iron environments.

scholarly journals Toxin Production by Pseudomonas Tolaasii Paine

1973 ◽  
Vol 26 (2) ◽  
pp. 509 ◽  
Author(s):  
NG Nair ◽  
PC Fahy
Keyword(s):  
Toxin Production ◽  
Nutrient Broth ◽  
Dialysis Membrane ◽  
Pseudomonas Tolaasii ◽  
Brown Discoloration

Evidence is presented for the production of toxin in vitro and in vivo by P. tolaasii. Nutrient broth suspensions of P. tolaasii placed on detached mushroom sporophores but separated by a dialysis membrane caused brown discoloration and slightly sunken lesions.

scholarly journals High glucose induces early senescence in adipose-derived stem cells by accelerating p16 and mTOR

2019 ◽  
Vol 6 (6) ◽  
pp. 3213-3221
Author(s):  
Hieu Liem Pham ◽  
Phuc Van Pham
Keyword(s):  
Stem Cells ◽  
High Glucose ◽  
Glucose Concentration ◽  
Culture Medium ◽  
Diabetic Patients ◽  
Adipose Derived Stem Cells ◽  
Differentiation Potential ◽  
Normal Glucose

Introduction: The senescence of stem cells is the primary reason that causes aging of stem cell-containing tissues. Some hypotheses have suggested that high glucose concentration in diabetic patients is the main factor that causes senescence of cells in those patients. This study aimed to evaluate the effects of high glucose concentrations on the senescence of adipose-derived stem cells (ADSCs). Methods: ADSCs were isolated and expanded from human adipose tissues. They were characterized and confirmed as mesenchymal stem cells (MSCs) by expression of surface markers, their shape, and in vitro differentiation potential. They were then cultured in 3 different media- that contained 17.5 mM, 35 mM, or 55 mM of D-glucose. The senescent status of ADSCs was recorded by the expression of the enzyme beta-galactosidase, cell proliferation, and doubling time. Real-time RT-PCR was used to evaluate the expression of p16, p21, p53 and mTOR. Results: The results showed that high glucose concentrations (35 mM and 55 mM) in the culture medium induced senescence of human ADSCs. The ADSCs could progress to the senescent status quicker than those cultured in the lower glucose-containing medium (17.5 mM). The senescent state was related to the up-regulation of p16 and mTOR genes. Conclusion: These results suggest that high glucose in culture medium can trigger the expression of p16 and mTOR genes which cause early senescence in ADSCs. Therefore, ADSCs should be cultured in low glucose culture medium, or normal glucose concentration, to extend their life in vitro as well as in vivo.  

IN VITRO HYPOGLYCEMIC EFFECTS OF CAESALPINIA BONDUCELLA AND MYRISTICA FRAGRANS SEED EXTRACTS

INDIAN DRUGS ◽  
2018 ◽  
Vol 55 (02) ◽  
pp. 57-62
Author(s):  
M. A Bhutkar ◽  
◽  
S. D Bhinge ◽  
D. S. Randive ◽  
G. H Wadkar ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Plant Extracts ◽  
Glucose Concentration ◽  
Yeast Cells ◽  
In Vivo Models ◽  
Myristica Fragrans ◽  
Glucose Diffusion ◽  
Caesalpinia Bonducella

The present investigation was undertaken to assess the hypoglycemic potential of Caesalpinia bonducella (C.bonducella) and Myristica fragrans (M.fragrans), employing various in vitro techniques. The extracts of seeds of C. bonducella and M. fragrans were studied for their effects on glucose adsorption capacity, in vitro glucose diffusion, in vitro amylolysis kinetics and glucose transport across the yeast cells. It was observed that the plant extracts under study adsorbed glucose and the adsorption of glucose increased remarkably with an increase in glucose concentration. There were no significant (p≤0.05) differences between their adsorption capacities. The results of amylolysis kinetic experimental model revealed that the rate of glucose diffusion was found to be increased with time from 30 to 180 min and both the plant extracts demonstrated significant inhibitory effects on movement of glucose into external solution across dialysis membrane as compared to control. Also, the plant extracts promoted glucose uptake by the yeast cells. It was observed that the enhancement of glucose uptake was dependent on both the sample and glucose concentration. C. bonducella extract exhibited significantly higher (p≤0.05) activity than the extract of M. fragrans at all concentrations. The results of the study verified the hypoglycemic activity of the extracts of C. bonducella and M. fragrans. However, the observed effects exhibited by the extracts of seeds of C. bonducella and M. fragrans need to be confirmed by using different in vivo models and clinical trials for their effective utilization as therapeutic agents in better management of diabetes mellitus.

In vitro analysis of glucose metabolism and embryonic growth in postimplantation rat embryos

Development ◽  
1987 ◽  
Vol 100 (3) ◽  
pp. 431-439 ◽  
Author(s):  
S.K. Ellington
Keyword(s):  
Glucose Metabolism ◽  
Embryonic Development ◽  
Glucose Uptake ◽  
Glucose Concentration ◽  
Culture Media ◽  
Rat Embryos ◽  
Embryonic Growth ◽  
Stage Of Development

The glucose metabolism and embryonic development of rat embryos during organogenesis was studied using embryo culture. Glucose uptake and embryonic growth and differentiation of 10.5-day explants (embryos + membranes) were limited by the decreasing glucose concentration, but not the increasing concentration of metabolites, in the culture media during the second 24 h of a 48 h culture. No such limitations were found on the embryonic development of 9.5-day explants during a 48 h culture although glucose uptake was slightly reduced at very low concentrations of glucose. From the head-fold stage to the 25-somite stage of development, glucose uptake was characteristic of the stage of development of the embryo and not the time it had been in culture. Embryonic growth of 9.5-day explants was similar to that previously observed in vivo. Glucose uptake by 9.5-day explants was dependent on the surface area of the yolk sac and was independent of the glucose concentration in the culture media (within the range of 9.4 to 2.5 mM). The proportion of glucose converted to lactate was 100% during the first 42h of culture then fell to about 50% during the final 6h. The protein contents of both the extraembryonic membranes and the embryo were dependent on the glucose uptake.

Effect of arginine depletion on glomerular and tubular kidney function: studies in isolated perfused rat kidneys

1991 ◽  
Vol 261 (5) ◽  
pp. F779-F786 ◽  
Author(s):  
J. Radermacher ◽  
B. Klanke ◽  
S. Kastner ◽  
G. Haake ◽  
H. J. Schurek ◽  
...  
Keyword(s):  
Flow Rate ◽  
Specific Inhibitor ◽  
Free Water ◽  
Renal Perfusion ◽  
Physiological Concentration ◽  
Perfusion Flow ◽  
Glucose Reabsorption ◽  
Glomerular Hemodynamics ◽  
Perfusion Flow Rate ◽  
Rat Kidneys

The effect of L-Arg depletion on glomerular hemodynamics and tubular function of isolated rat kidneys perfused with a medium containing 21 amino acids has been studied. A cyclooxygenase inhibitor was added throughout for blockade of prostaglandin synthesis. Arg depletion caused significant (approximately 30%) reductions in renal perfusion flow rate (PFR, 13.9 +/- 1.2 vs. 19.8 +/- 0.6 ml.min-1.g (kidney wt-1), glomerular filtration rate (GFR, 598 +/- 79 vs. 924 +/- 42 microliters.min-1.g kidney wt-1), and urine flow rate (139 +/- 38 vs. 192 +/- 13 microliters.min-1.g kidney wt-1) compared with control kidneys, which were perfused with a physiological concentration of Arg (200 microM). Filtration fraction (FF) increased with Arg depletion (5.1 +/- 0.4 vs. 4.4 +/- 0.4%). Arg-depleted kidneys had a lower absolute sodium (TNa, 75.7 +/- 8.8 vs. 107.9 +/- 6.0 mumol.min-1.g kidney wt-1) and glucose reabsorption (T glucose, 3.7 +/- 0.6 vs. 5.6 +/- 0.5 mumol.min-1.g kidney wt-1), corresponding to a lower sodium and glucose filtration. Potassium handling and reabsorption of free water were not changed. Oxygen consumption (QO2) was lower in Arg-depleted kidneys (4.6 +/- 0.3 vs. 5.5 +/- 0.5 mumol.min-1.g kidney wt-1). The effects of Arg depletion were completely reversed by the addition of Arg (1 mM) at 120 min and partly reversed by the addition of citrulline (1 mM). Ornithine depletion or addition had no effect on PFR, GFR, FF, TNa, T glucose, and QO2. N omega-methyl-L-arginine, a specific inhibitor of nitric oxide endothelium-derived relaxing factor, produced the same effect as Arg depletion.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Novel Dissolution Approach for Tacrolimus-Loaded Microspheres Using a Dialysis Membrane for in Vitro–in Vivo Correlation

2019 ◽  
Vol 67 (5) ◽  
pp. 467-475 ◽  
Author(s):  
Masanori Kaihara ◽  
Kazuhiro Hojo ◽  
Tomokazu Tajiri ◽  
Atsushi Kambayashi ◽  
Takatsune Yoshida ◽  
...  
Keyword(s):  
Dialysis Membrane

Intestinal filtration-secretion due to increased intraluminal pressure in rabbits

1982 ◽  
Vol 242 (1) ◽  
pp. G65-G75
Author(s):  
E. A. Swabb ◽  
R. A. Hynes ◽  
W. G. Marnane ◽  
J. S. McNeil ◽  
R. A. Decker ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Surface Area ◽  
Intestinal Transport ◽  
Blood Flow Rate ◽  
Intraluminal Pressure ◽  
Rabbit Ileum ◽  
Venous Dilatation ◽  
Small Intestinal

The mechanism of changes in small intestinal transport due to acutely increased intraluminal hydrostatic pressure (IHP) was investigated in detail using perfused in vivo rabbit intestinal segments. IHP affected passive transport in vivo by increasing effective mucosal surface area in the small intestine (indicated by 3HOH transport and tissue architectural changes) and increasing small intestinal permeability (indicated by a proportionately greater increase in mannitol than erythritol secretory clearance). IHP did not alter ileal blood flow rate measured by radioactive microspheres, despite grossly evident venous dilatation, or active intestinal transport in the ileum as measured by a) in vitro ion transport in the absence of elevated hydrostatic pressure, b) mucosal adenylate cyclase or Na-K-ATPase activities, and c) glucose-stimulated water and electrolyte absorption. Acutely increased IHP appears to influence the hydrodynamics of the mucosal microcirculation in the rabbit ileum to produce a driving force for passive filtration-secretion, which is associated with and possibly augmented by increased tissue permeability and effective surface area.

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