Effect of peak inspiratory pressure on the filtration coefficient in the isolated perfused rat lung.
Animals; Biological; Body Fluids/physiology; Capillary Permeability; Evaluation Studies as Topic; In Vitro Techniques; Lung/blood supply/*physiology; Male; Models; Perfusion; Positive-Pressure Respiration; Pressure; Rats; Respiration/physiology; Sprague-Dawley
Positive inspiratory pressure- (PIP) ventilated, isolated rat lungs become edematous when perfused at rates approximately the normal cardiac output. The study was conducted to test the hypothesis that high peak inspiratory pressures contribute to the edema development. Five isolated lungs were perfused at a rate of 24.4 +/- 2.2 ml.min-1.100 g body wt-1 with 40% whole blood (diluted with saline containing 4.0 g/100 ml bovine serum albumin) and ventilated with peak pressures ranging from 0 to 20 mmHg. The lungs exhibited edema at PIP values \textgreater 9.3 mmHg. The stable pulmonary vascular pressure and resistance suggested that the edema may have resulted from a PIP-induced increase in microvascular permeability. In a second study, the stability of the preparation was evaluated during a 3-h test period. Seven lungs were ventilated at a peak inspiratory pressure of 8.0 mmHg and perfused at 26.8 +- 1.7 ml.min-1 x 100 g body wt-1. Microvascular integrity was maintained for approximately 2 h as indicated by filtration coefficient measurements of 0.175 +/- 0.068, 0.197 +/- 0.066, and 0.169 +/- 0.067 g.min-1 x mmHg-1 x 100 g-1 at 25, 70, and 115 min, respectively, after initiation of the study. The results suggest that isolated rat lungs perfused at rates that parallel normal rat cardiac output and ventilated at low peak inspiratory pressures provide a viable mechanism for evaluation of the pathophysiology of microvascular injury.
Omlor G; Niehaus G D; Maron M B
Journal of applied physiology (Bethesda, Md. : 1985)
1993
1993-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/jappl.1993.74.6.3068" target="_blank" rel="noreferrer noopener">10.1152/jappl.1993.74.6.3068</a>
Functional outcome after anal sphincter injury and treatment with mesenchymal stem cells.
Female; Time Factors; Animals; Rats; Mesenchymal stem cells; Transfection; Recovery of Function; Fibrosis; *Mesenchymal Stem Cell Transplantation; *Regeneration; Anal Canal/injuries/metabolism/pathology/physiopathology/*surgery; Anal pressures; Anal sphincter; Fecal incontinence; Green Fluorescent Proteins/biosynthesis/genetics; i.v. infusion; Mesenchymal Stem Cells/metabolism; Pressure; Injections; Intralesional; Sprague-Dawley; Cells; Cultured; Animal; Disease Models; Infusions; Intravenous
This research demonstrates the regenerative effects of mesenchymal stem cells (MSCs) on the injured anal sphincter by comparing anal sphincter pressures following intramuscular and serial intravascular MSC infusion in a rat model of anal sphincter injury. Fifty rats were divided into injury (n = 35) and no injury (NI; n = 15) groups. Each group was further divided into i.m., serial i.v., or no-treatment (n = 5) groups and followed for 5 weeks. The injury consisted of an excision of 25% of the anal sphincter complex. Twenty-four hours after injury, 5 x 10(5) green fluorescent protein-labeled MSCs in 0.2 ml of phosphate-buffered saline (PBS) or PBS alone (sham) were injected into the anal sphincter for i.m. treatment; i.v. and sham i.v. treatments were delivered daily for 6 consecutive days via the tail vein. Anal pressures were recorded before injury and 10 days and 5 weeks after treatment. Ten days after i.m. MSC treatment, resting and peak pressures were significantly increased compared with those in sham i.m. treatment (p \textless .001). When compared with the NI group, the injury groups had anal pressures that were not significantly different 5 weeks after i.m./i.v. treatment. Both resting and peak pressures were also significantly increased after i.m./i.v. MSC treatment compared with treatment with PBS (p \textless .001), suggesting recovery. Statistical analysis was done using paired t test with Bonferroni correction. Marked decrease in fibrosis and scar tissue was seen in both MSC-treated groups. Both i.m. and i.v. MSC treatment after injury caused an increase in anal pressures sustained at 5 weeks, although fewer cells were injected i.m. The
Salcedo Levilester; Penn Marc; Damaser Margot; Balog Brian; Zutshi Massarat
Stem cells translational medicine
2014
2014-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.5966/sctm.2013-0157" target="_blank" rel="noreferrer noopener">10.5966/sctm.2013-0157</a>
Increased transperitoneal bacterial translocation in laparoscopic surgery.
*Bacterial Translocation; *Laparoscopy; Animal; Animals; Artificial/*adverse effects/methods; Carbon Dioxide/administration & dosage; Escherichia coli Infections/*microbiology; Escherichia coli/isolation & purification/physiology; Gases; Helium/administration & dosage; Insufflation/adverse effects; Male; Models; Peritonitis/*microbiology; Pneumoperitoneum; Pressure; Rats; Sprague-Dawley
BACKGROUND: The indications for laparoscopic surgery have expanded to include diseases possibly associated with peritonitis such as appendicitis, perforated peptic ulcers, and diverticulitis. The safety of carbon dioxide (CO2) pneumoperitoneum in the presence of peritonitis has not been proved. Our previous investigations demonstrated increased bacteremia associated with CO2 insufflation. In effort to clarify the relative effects of intraabdominal pressure and type of gas, this study was designed to measure bacterial translocation with different gases at different pressures of pneumoperitoneum. METHODS: For this study, 110 rats were given intraperitoneal bacterial innoculations with Escherichia coli and equally divided into five groups of 20 animals each. The study groups included a control group with no pneumoperitoneum administered (n = 30), insufflation at a commonly used pressure of 14 mmHg with helium (n = 20) and CO2 (n = 20), and low insufflation at 3 mmHg with helium (n = 20) and CO2 (n = 20) in an effort to minimize influences related to pressure. Blood cultures were checked at 15-min intervals for the first 45 min, then hourly thereafter for a total of 165 min after peritoneal inoculation with 2 x 10(7) E. coli. RESULTS: There is increased risk of bacterial translocation in comparing groups that underwent pneumoperitoneum with those that did not in the rat peritonitis model. Furthermore, these findings are dependent on the presence or absence of gas, but not necessarily on the type of gas used for insufflation. In the low-pressure groups of both gases (helium and CO2), bacterial translocation was significantly increased, as compared with the control group. Low pressure also was associated with increased bacterial translocation, as compared with high pressure, but beyond 30 min of insufflation, no significant differences were apparent. CONCLUSIONS: The risk of bacterial translocation in the E. coli rat peritonitis model is increased with insufflation using CO2 or helium, and this effect is more significant at lower pressures (3 mmHg) than at higher pressures (14 mmHg). However, no clinically applicable conclusions regarding the relative effects from type of gas or insufflation pressures could be confirmed.
Horattas M C; Haller N; Ricchiuti D
Surgical endoscopy
2003
2003-09
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1007/s00464-001-8289-1" target="_blank" rel="noreferrer noopener">10.1007/s00464-001-8289-1</a>
TRADITIONAL M-MODE ASSESSMENT OF INFERIOR VENA CAVA COLLAPSIBILITY IS NOT RELIABLE - A ROLE FOR 3D IMAGING?
Measurements of IVC (1-2 cm from Cavoatrial junction) were obtained in 34 patients using 2D and M mode as well as 3D Echo. Using multiplanar reconstruction, true short axis views of the IVC were obtained at the level of IVC measurement in 2D and M mode. APD was measured in M mode and 3D, at baseline and during sniff maneuver.
Echo assessment of right atrial pressure (RAP), based on anteroposterior diameter (APD) of inferior vena cava (IVC) and IVC collapsibility with sniff maneuver, often does not corelate with clinical or invasive assessment of volume status. We hypothesize, translation of the plane of insonation during sniff maneuver could lead to overestimation or underestimation of IVC collapsibility by M mode. A 3D approach could evaluate IVC collapsibility better.
Gopalakrishnan P; Potakamuri L
Journal Of The American College Of Cardiology
2021
2021-05-03
Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
Journal Article
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Using O2 to probe membrane immersion depth by 19F NMR.
*Hydrocarbons; *Oxygen; Biological; Cyclic N-Oxides; Dimyristoylphosphatidylcholine/*chemistry; Fluorinated; Fluorine; Lipid Bilayers/*chemistry; Magnetic Resonance Spectroscopy/*methods; Maltose/*analogs & derivatives; Models; Phospholipid Ethers/*chemistry; Pressure; Spin Labels
A fluorinated detergent, CF(3)(CF(2))(5)C(2)H(4)-O-maltose, was reconstituted into a lipid bilayer model membrane system to demonstrate the feasibility of determining solvent accessibility and membrane immersion depth of each fluorinated group by (19)F NMR. Apolar oxygen, which is known to partition with an increasing concentration gradient toward the hydrophobic membrane interior, exhibits a range of paramagnetic relaxation effects on (19)F nuclei, depending on its depth in the membrane. This effect, which is predominately associated with spin-lattice relaxation rates (R(1)) and chemical shifts, can be amplified greatly with minimal line broadening by increasing the partial pressure of O(2) at least 100-fold (i.e., P(O(2)) greater than 20 bar). The differences of longitudinal relaxation rates at 20 bar of oxygen pressure to those under ambient pressure (R(1)(20bar) - R(1)(0)) are largest for those fluorine groups expected to be most deeply buried in the membrane bilayer. This result contrasts with the reverse trend, which is observed on addition of a membrane surface-associated paramagnetic species, 4-(N,N-dimethyl-N-hexadecyl) ammonium-2,2,6,6-tetramethylpiperidine-1-oxyl iodide (CAT-16) at ambient pressures. Thus, differential relaxation rates may be observed in (19)F-labeled membrane-associated molecules resulting from the addition of apolar oxygen under high pressure. The results demonstrate that the degree of solvent accessibility and membrane immersion depth of specific fluorinated species in membrane-associated macromolecules can be probed by (19)F NMR.
Prosser R S; Luchette P A; Westerman P W
Proceedings of the National Academy of Sciences of the United States of America
2000
2000-08
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1073/pnas.170295297" target="_blank" rel="noreferrer noopener">10.1073/pnas.170295297</a>