An in vitro study of the effects of isoflurane on oxygen transfer

Perfusion ◽  
2001 ◽  
Vol 16 (4) ◽  
pp. 293-299 ◽  
Author(s):  
Michelle L Muhle ◽  
Alfred H Stammers ◽  
Kimberly D Tremain ◽  
Kevin S Niimi ◽  
Kimberly R Glogowski ◽  
...  
Keyword(s):  
Oxygen Transfer ◽  
Gas Flow ◽  
In Vitro Study ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Anesthetic Technique ◽  
Vitro Model ◽  
The Given

A common anesthetic technique utilized during cardiopulmonary bypass (CPB) includes the use of various inhalation agents, such as isoflurane. The purpose of this study was to evaluate the effects of this agent on oxygen transfer during CPB. An in vitro model was designed using bovine blood. Blood flow was held constant at 2 l/min, while gas flow was manipulated at 1 and 3 l/min. The percentage of inspired oxygen (FiO2) was set at 50 and 100%, and isoflurane was manipulated to 1.0, 3.0 and 5.0%. Blood gas analysis, oxygen transfer, and inlet and outlet isoflurane concentrations were measured at each of the given conditions. A total of 12 trials with four oxygenators were conducted. In the four oxygenators used in our study, no significant differences in oxygenator performance were found. At conditions of 1 l/min gas flow, 50% FiO2 and 1% isoflurane, there were no significant changes in O2 transfer between baseline and measurements taken during isoflurane administration (100.18 ± 12.49 vs 102.35 ± 10.99 ml O2/min, p=0.8031). At 3 l/min gas flow, 100% FiO2 and 5% isoflurane, no significant differences were found (142.35 ± 10.76 vs 154.04 ± 8.95 ml O2/min, p=0.1459). The only significant differences found for oxygen transfer were between 50 and 100% FiO2, all other conditions being set equal (102.35 ± 10.99 vs 137.68 ± 8.62 ml O2/min, p=0.0023). In conclusion, increasing concentrations of isoflurane up to 5% does not affect the efficiency of oxygen transfer in an in vitro circuit. Further studies are necessary to evaluate the effects in an in vivo setting.

Studies in Cranial Suture Biology: In Vitro Cranial Suture Fusion

1996 ◽  
Vol 33 (2) ◽  
pp. 150-156 ◽  
Author(s):  
James P. Bradley ◽  
Jamie P. Levine ◽  
Christopher Blewett ◽  
Thomas Krummel ◽  
Joseph G. Mccarthy ◽  
...  
Keyword(s):  
Organ Culture ◽  
In Vitro Model ◽  
In Vitro Study ◽  
Cranial Base ◽  
Cranial Suture ◽  
Model Study ◽  
Suture Fusion ◽  
Vitro Model

The biology underlying craniosynostosis remains unknown. Previous studies have shown that the underlying dura mater, not the suture itself, signals a suture to fuse. The purpose of this study was to develop an in vitro model for cranial-suture fusion that would still allow for suture-dura interaction, but without the influence of tensional forces transmitted from the cranial base. This was accomplished by demonstrating that the posterior frontal mouse cranial suture, known to be the only cranial suture that fuses in vivo, fuses when plated with its dura in an organ-culture system. In such an organ-culture system, the sutures are free from both the influence of dural forces transmitted from the cranial base and from hormonal influences only available in a perfused system. For the cranial-suture fusion in vitro model study, the sagittal sutures (controls that remain patent in vivo) and posterior frontal sutures (that fuse in vivo) with the underlying dura were excised from 24-day-old euthanized mice, cut into 5 × 4 × 2-mm specimens, and cultured in a chemically defined, serum-free media. One hundred sutures were harvested at the day of sacrifice, then every 2 days thereafter until 30 days in culture, stained with H & E, and analyzed. A subsequent cranial-suture without dura in vitro study was performed in a similar fashion to the first study, but only the calvariae with the posterior frontal or sagittal sutures (without the underlying dura) were cultured. Results from the cranial-suture fusion in vitro model study showed that all sagittal sutures placed in organ culture with the underlying dura remained patent. More importantly, the posterior frontal sutures with the underlying dura, which were plated-down as patent at 24 days of age, demonstrated fusion after various growth periods in organ culture. In vitro posterior frontal mouse-suture fusion occurred in an anterior-to-posterior direction but in a delayed fashion, 4 to 7 days later than in vivo posterior frontal mouse-suture fusion. In contrast, the subsequent cranial-suture without dura in vitro study showed patency of all sutures, including the posterior frontal suture. These data from in vitro experiments indicate that: (1) mouse calvariae, sutures, and the underlying dura survive and grow in organ-culture systems for 30 days; (2) the local dura, free from external influences transmitted from the cranial base and hormones from distant sites, influences the cells of its overlying suture to cause fusion; and (3) without dura influence, all in vitro cranial sutures remained patent. By first identifying the factors involved in dural-suture signaling and then regulating these factors and their receptors, the biologic basis of suture fusion and craniosynostosis may be unraveled and used in the future to manipulate pathologic (premature) suture fusion.

An In Vivo/In Vitro Study of Allyl Alcohol Toxicity Using Enzyme Inhibitors

1993 ◽  
Vol 21 (1) ◽  
pp. 38-42
Author(s):  
Romana Pulci ◽  
Donatella Moneta ◽  
Philippe Dostert ◽  
Marco Brughera ◽  
Giovanna Scampini ◽  
...  
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Allyl Alcohol ◽  
In Vitro Model ◽  
Enzyme Inhibitors ◽  
In Vitro Study ◽  
Rat Hepatocytes ◽  
Isolated Rat Hepatocytes ◽  
Vitro Model

The aim of this study was to verify an in vitro model of hepatotoxicity, designed to assess the production of reactive species from biologically-inert chemicals through their metabolic transformation. One example is allyl alcohol, which produces acrolein through the action of the enzyme alcohol dehydrogenase. Acrolein is a highly hepatotoxic aldehyde which is detoxified to acrylic acid by aldehyde dehydrogenase (ALDH). A deficiency of this enzyme, common in some Asian populations, can give rise to pathological conditions of hepatotoxicity. Isolated rat hepatocytes were incubated with allyl alcohol with and without cyanamide, a known inhibitor of ALDH. The toxicity of allyl alcohol, assessed on the basis of release of glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT) and lactate dehydrogenase (LDH) into the culture medium, was dramatically increased by the addition of cyanamide. In vivo, the same treatment scheme was used in rats treated with allyl alcohol with or without cyanamide pretreatment. It was also demonstrated that allyl alcohol toxicity is dramatically enhanced by the addition of an aldehyde dehydrogenase inhibitor, as shown by plasma levels of hepatic enzymes (GOT, GPT and LDH) and by histological findings. We believe that this in vitro model, involving the use of enzyme inhibitors, could be useful for verification of the hypothesis that hepatotoxins, such as acrolein, are produced from some pharmaceutical and other chemical compounds.

Heat analysis of different devices for thermo-explantation of dental implants: a numeric analysis and preclinical in-vitro model

2020 ◽  
Author(s):  
Kristian Kniha ◽  
Frank Hölzle ◽  
Faruk Al-Sibai ◽  
Johannes Jörg ◽  
Reinhold Kneer ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Threshold Level ◽  
Future Research ◽  
Heating Process ◽  
Time Interval ◽  
Electric Device ◽  
Infrared Measurements ◽  
Vitro Model

Thermal treatment may reverse the osseointegration of implants and could become an atraumatic controlled method for implant removal in the future. The aim of this non-random in vitro study was to empirically identify suitable sources for a controlled heating process, in order to generate a homogenous temperature distribution at a threshold level of 47°C for future in vivo research. Two different set-ups evaluating four different sources (water, laser, monopolar and an electrical joule heater device) were used to carry out infrared measurements and numerical calculations at 47°C along the implant axis and along the periimplant area at the axial plane. Furthermore, required time intervals to heat up the implant tip from 33°C to 47°C were determined. The monopolar electric device led to the most uneven and unpredictable implant heating and was therefore excluded. The thermal analysis suggested identical thermal distributions without any significant differences for water and electrical joule sources with a heat maximum at the implant shoulder (p > 0.05). On the other hand, the laser device may produce the temperature maximum in the middle of the implant without any afterglow effect (p < 0.01). When the implant was heated from 33°C up to 47°C, the water device indicated the fastest approach. Thermal distributions of water and laser sources may be suitable for clinical applications. For future research the numerical analysis may suggests an ideal time interval of 120s to 180s for a homogenous implant temperature of 47°C.

Syringomyelia Hydrodynamics: An In Vitro Study Based on In Vivo Measurements

2005 ◽  
Vol 127 (7) ◽  
pp. 1110-1120 ◽  
Author(s):  
Bryn A. Martin ◽  
Wojciech Kalata ◽  
Francis Loth ◽  
Thomas J. Royston ◽  
John N. Oshinski
Keyword(s):  
Spinal Cord ◽  
Wall Motion ◽  
In Vitro Model ◽  
Fluid Velocity ◽  
In Vitro Study ◽  
Elastic Tube ◽  
Flow Waveform ◽  
Vitro Model

A simplified in vitro model of the spinal canal, based on in vivo magnetic resonance imaging, was used to examine the hydrodynamics of the human spinal cord and subarachnoid space with syringomyelia. In vivo magnetic resonance imaging (MRI) measurements of subarachnoid (SAS) geometry and cerebrospinal fluid velocity were acquired in a patient with syringomyelia and used to aid in the in vitro model design and experiment. The in vitro model contained a fluid-filled coaxial elastic tube to represent a syrinx. A computer controlled pulsatile pump was used to subject the in vitro model to a CSF flow waveform representative of that measured in vivo. Fluid velocity was measured at three axial locations within the in vitro model using the same MRI scanner as the patient study. Pressure and syrinx wall motion measurements were conducted external to the MR scanner using the same model and flow input. Transducers measured unsteady pressure both in the SAS and intra-syrinx at four axial locations in the model. A laser Doppler vibrometer recorded the syrinx wall motion at 18 axial locations and three polar positions. Results indicated that the peak-to-peak amplitude of the SAS flow waveform in vivo was approximately tenfold that of the syrinx and in phase (SAS∼5.2±0.6ml∕s,syrinx∼0.5±0.3ml∕s). The in vitro flow waveform approximated the in vivo peak-to-peak magnitude (SAS∼4.6±0.2ml∕s,syrinx∼0.4±0.3ml∕s). Peak-to-peak in vitro pressure variation in both the SAS and syrinx was approximately 6 mm Hg. Syrinx pressure waveform lead the SAS pressure waveform by approximately 40 ms. Syrinx pressure was found to be less than the SAS for ∼200ms during the 860-ms flow cycle. Unsteady pulse wave velocity in the syrinx was computed to be a maximum of ∼25m∕s. LDV measurements indicated that spinal cord wall motion was nonaxisymmetric with a maximum displacement of ∼140μm, which is below the resolution limit of MRI. Agreement between in vivo and in vitro MR measurements demonstrates that the hydrodynamics in the fluid filled coaxial elastic tube system are similar to those present in a single patient with syringomyelia. The presented in vitro study of spinal cord wall motion, and complex unsteady pressure and flow environment within the syrinx and SAS, provides insight into the complex biomechanical forces present in syringomyelia.

scholarly journals Macrophage phagocytosis of Candida albicans. An in vitro study

1999 ◽  
Vol 13 (3) ◽  
pp. 233-238 ◽  
Author(s):  
Ilan WEINFELD ◽  
Esther Goldenberg BIRMAN ◽  
Claudete Rodrigues PAULA
Keyword(s):  
Candida Albicans ◽  
In Vitro Study ◽  
Neutral Red ◽  
Serotype A ◽  
Macrophage Phagocytosis ◽  
Serotype B ◽  
Vitro Model ◽  
Different Strains

Considering the role of macrophages in relation to fungi and the various utilized methodologies, the authors established an in vitro model to evaluate macrophage phagocytosis of Candida albicans. Activated macrophages were obtained from the peritoneal cavity of isogenic mice (A/Sn). Two different strains of Candida albicans serotype A and serotype B with different levels of pathogenicity in vivo and other similar characteristics were utilized in the study. Several microscopic fields containing about 200 macrophages were counted. The percentage of macrophages phagocytizing at least one viable or nonviable yeast cell determined an average number of phagocytized yeasts. Neutral red and fluorescein diacetate plus ethidium bromide were used for staining. It is possible to conclude that this is an efficient model related to the used methodology. The average number of yeasts in both strains were similar when inside macrophages, and there was a higher percentage of C. albicans serotype A phagocytosis, which was not experimentally pathogenic in vivo.

An in Vitro Assessment of a Monitor for Continuous Inline Measurement of PO2, PCO2 and pH during Cardiopulmonary Bypass

Perfusion ◽  
1987 ◽  
Vol 2 (2) ◽  
pp. 139-147 ◽  
Author(s):  
R Peter Alston ◽  
Arthur Trew
Keyword(s):  
Cardiopulmonary Bypass ◽  
In Vitro Model ◽  
Blood Gas Analysis ◽  
Systematic Errors ◽  
Gas Analysis ◽  
Blood Gas ◽  
In Vitro Assessment ◽  
Vitro Model ◽  
Inline Measurement

The Gas STAT is a monitor which continuously measures PO2. PCO2 and pH inline during cardiopulmonary bypass. Using an in vitro model, the monitor's accuracy was compared to standard blood gas analysis over a range of PO2 (2·0–66·7 kPa), PCO2 (2·7–12·0 kPa) and pH (7–8). Its stability as affected by time, temperature, flow and haematocrit and the presence of halothane, enflurane, isoflurane and sodium nitroprusside was examined. Good correlations were found between the monitor and standard blood gas analysis for PO2 (r = 0·999, P < 0·001) and PCO2 (r = 0·996, P < 0·001). However, large and unpredictable systematic errors occurred. It was stable under all conditions examined, except that in one sensor there was a statistically significant decline in PCO2 measurement with time (P < 0·005) and the PCO2 readings were affected by temperature (P < 0·021). The monitor provides useful information for blood gas management during cardiopulmonary bypass, but should not be used without recourse to standard blood gas analysis.

scholarly journals Learned spectral decoloring enables photoacoustic oximetry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Janek Gröhl ◽  
Thomas Kirchner ◽  
Tim J. Adler ◽  
Lina Hacker ◽  
Niklas Holzwarth ◽  
...  
Keyword(s):  
Photoacoustic Imaging ◽  
Initial Pressure ◽  
Blood Gas Analysis ◽  
Spatial Location ◽  
Gas Analysis ◽  
Blood Oxygenation ◽  
Tissue Properties ◽  
Light Fluence

AbstractThe ability of photoacoustic imaging to measure functional tissue properties, such as blood oxygenation sO$$_2$$ 2 , enables a wide variety of possible applications. sO$$_2$$ 2 can be computed from the ratio of oxyhemoglobin HbO$$_2$$ 2 and deoxyhemoglobin Hb, which can be distuinguished by multispectral photoacoustic imaging due to their distinct wavelength-dependent absorption. However, current methods for estimating sO$$_2$$ 2 yield inaccurate results in realistic settings, due to the unknown and wavelength-dependent influence of the light fluence on the signal. In this work, we propose learned spectral decoloring to enable blood oxygenation measurements to be inferred from multispectral photoacoustic imaging. The method computes sO$$_2$$ 2 pixel-wise, directly from initial pressure spectra $$S_{\text {p}_0}(\lambda , \mathbf {x})$$ S p 0 ( λ , x ) , which represent initial pressure values at a fixed spatial location $$\mathbf {x}$$ x over all recorded wavelengths $$\lambda$$ λ . The method is compared to linear unmixing approaches, as well as pO$$_2$$ 2 and blood gas analysis reference measurements. Experimental results suggest that the proposed method is able to obtain sO$$_2$$ 2 estimates from multispectral photoacoustic measurements in silico, in vitro, and in vivo.

In Vitro Study of the Flush Effect in Two Reusable Continuous Ambulatory Peritoneal Dialysis (CAPD) Disconnect Systems

1989 ◽  
Vol 9 (3) ◽  
pp. 169-173 ◽  
Author(s):  
Mary Anne Luzar ◽  
Alain Slingeneyer ◽  
Alberto Cantaluppi ◽  
Francesco P. Peluso
Keyword(s):  
Peritoneal Dialysis ◽  
Continuous Ambulatory Peritoneal Dialysis ◽  
In Vitro Study ◽  
Significant Difference ◽  
Pure Cultures ◽  
Single Use ◽  
Vitro Model ◽  
Multiple Samples

Previously published in vitro results, confirmed by clinical studies, indicate that the use of a flush significantly reduces peritonitis in single-use and reusable continuous ambulatory peritoneal dialysis (CAPD) systems. Since reusable systems may use the flush plus inline disinfectant between exchanges, the question remains as to whether or not the flush could be used alone in all disconnect systems. Using an in vitro model, we evaluated the flush in two reusable disconnect systems that use both flush and disinfectant in vivo. In a series of twenty sets per organism per incubation (0 h and 10 h), Y sets were inoculated in the lumen with three pure cultures (103 CFU range). Ability of flush without disinfectant to clear sets of contamination was analyzed by collecting multiple samples at each step of the procedure, enriching with tryptone broth and verifying bacterial growth. When contaminated sets were not incubated, flush efficacy of the systems was consistent with previous data showing 100% removal of Staphylococcus epidermidis, but only partial elimination of Staphylococcus aureus and Pseudomonas aeruginosa. After incubation, simulating reusable systems, the flush was able to eliminate S. epidermidis less than 50% of the time. There was no significant difference in results between the two systems tested. Reusable systems allow more contact time between bacteria and plastic resulting in reduced flush efficacy suggesting that, for safest conditions, they should be used with inline disinfectants.

Effects of TSH and calcitriol on bone metabolism: in vivo and in vitro study

2014 ◽  
Author(s):  
Ivo Dumic-Cule ◽  
Dunja Rogic ◽  
Damir Jezek ◽  
Lovorka Grgurevic ◽  
Slobodan Vukicevic
Keyword(s):  
Bone Metabolism ◽  
In Vitro Study ◽  
Vitro Study
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