Application of a single-compartment model for estimation of styrene uptake from measurements of urinary excretion of mandelic and phenylglyoxylic acids after occupational exposure

1996 ◽  
Vol 68 (5) ◽  
pp. 337-341
Author(s):  
Kent Wrangskog ◽  
Jan Sollenberg ◽  
Erik Söderman
Keyword(s):  
Occupational Exposure ◽  
Urinary Excretion ◽  
Compartment Model ◽  
Single Compartment ◽  
Single Compartment Model

A single compartment model of pacemaking in dissasociated Substantia nigra neurons

2013 ◽  
Vol 35 (3) ◽  
pp. 295-316 ◽  
Author(s):  
Febe Francis ◽  
Míriam R. García ◽  
Richard H. Middleton
Keyword(s):  
Substantia Nigra ◽  
Compartment Model ◽  
Single Compartment ◽  
Single Compartment Model

scholarly journals Quantitative analysis of flux along the gluconeogenic, glycolytic and pentose phosphate pathways under reducing conditions in hepatocytes isolated from fed rats

1983 ◽  
Vol 212 (3) ◽  
pp. 585-598 ◽  
Author(s):  
J M Crawford ◽  
J J Blum
Keyword(s):  
Compartment Model ◽  
Pentose Phosphate ◽  
Improved Method ◽  
Single Compartment ◽  
Reducing Conditions ◽  
Single Compartment Model ◽  
Net Flux ◽  
Pentose Phosphate Pathways ◽  
Fructose 1,6 Bisphosphate ◽  
Hexose Phosphates

Hepatocytes were isolated from the livers of fed rats and incubated with a mixture of glucose (10 mM), ribose (1 mM), mannose (4 mM), glycerol (3 mM), acetate (1.25 mM), and ethanol (5 mM) with one substrate labelled with 14C in any given incubation. Incorporation of label into CO2, glucose, glycogen, lipid glycerol and fatty acids, acetate and C-1 of glucose was measured at 20 and 40 min after the start of the incubation. The data (about 48 measurements for each interval) were used in conjunction with a single-compartment model of the reactions of the gluconeogenic, glycolytic and pentose phosphate pathways and a simplified model of the relevant mitochondrial reactions. An improved method of computer analysis of the equations describing the flow of label through each carbon atom of each metabolite under steady-state conditions was used to compute values for the 34 independent flux parameters in this model. A good fit to the data was obtained, thereby permitting good estimates of most of the fluxes in the pathways under consideration. The data show that: net flux above the level of the triose phosphates is gluconeogenic; label in the hexose phosphates is fully equilibrated by the second 20 min interval; the triose phosphate isomerase step does not equilibrate label between the triose phosphates; substrate cycles are operating at the glucose-glucose 6-phosphate, fructose 6-phosphate-fructose 1,6-bisphosphate and phosphoenolpyruvate-pyruvate-oxaloacetate cycles; and, although net flux through the enzymes catalysing the non-oxidative steps of the pentose phosphate pathway is small, bidirectional fluxes are large.

Influence of nonlinearities on estimates of respiratory mechanics using multilinear regression analysis

1994 ◽  
Vol 77 (3) ◽  
pp. 1185-1197 ◽  
Author(s):  
S. Kano ◽  
C. J. Lanteri ◽  
A. W. Duncan ◽  
P. D. Sly
Keyword(s):  
Respiratory System ◽  
Respiratory Mechanics ◽  
Compartment Model ◽  
Multilinear Regression ◽  
Multilinear Regression Analysis ◽  
Single Compartment ◽  
Dependent Component ◽  
Single Compartment Model ◽  
Volume Controlled ◽  
Pressure Controlled

To investigate the influence of nonlinearities on estimates of respiratory mechanics, differing patterns of mechanical ventilation patterns were analyzed from 8 puppies and 14 children. Respiratory mechanics were calculated using multiple linear regression to fit a linear single-compartment model, a volume-dependent single-compartment model (VDSCM), and a flow-dependent single-compartment model. The ratio of the compliance of the last 20% of the dynamic volume-pressure (V-P) curve to the total compliance (C20/C) and the contribution of a volume-dependent elastance to total elastance [%E2 = E2 (VT)/[(E1 + E2)VT], where E1 + E2 is total elastance, E2 is the volume-dependent component, and VT is tidal volume] were used as the indexes of over-distension. By positioning the dynamic loops on the static V-P curves, ventilation patterns were classified as overdistended or nonoverdistended. In the overdistended group, the C20/C was significantly lower (0.71 +/- 0.10 vs. 0.92 +/- 0.16; P < 0.0001) and %E2 was significantly higher (43.4 +/- 15.0 vs. 0.51 +/- 18.02%, P < 0.0001) than in the nonoverdistended group. The mode of ventilation (pressure controlled vs. volume controlled) and the resistive pressures that resulted in widening of the dynamic V-P loop were found to alter C20/C but not %E2. When the respiratory system was overdistended, i.e., ventilated up to the flattened portion of the V-P curve, the VDSCM gave more accurate estimates of respiratory mechanisms. Furthermore, %E2 calculated from VDSCM is a useful parameter for estimating respiratory system overdistension that is not affected by resistive pressures.

scholarly journals Using injury cost functions from a predictive single-compartment model to assess the severity of mechanical ventilator-induced lung injuries

2019 ◽  
Vol 127 (1) ◽  
pp. 58-70 ◽  
Author(s):  
Michelle M. Mellenthin ◽  
Siyeon A. Seong ◽  
Gregory S. Roy ◽  
Elizabeth Bartolák-Suki ◽  
Katharine L. Hamlington ◽  
...  
Keyword(s):  
Lung Injury ◽  
Power Dissipation ◽  
Compartment Model ◽  
Mechanical Power ◽  
Cost Functions ◽  
Mechanical Ventilator ◽  
Ventilator Induced Lung Injury ◽  
Single Compartment ◽  
Single Compartment Model ◽  
Ventilator Settings

Identifying safe ventilation patterns for patients with acute respiratory distress syndrome remains challenging because of the delicate balance between gas exchange and selection of ventilator settings to prevent further ventilator-induced lung injury (VILI). Accordingly, this work seeks to link ventilator settings to graded levels of VILI to identify injury cost functions that predict injury by using a computational model to process pressures and flows measured at the airway opening. Pressure-volume loops were acquired over the course of ~2 h of mechanical ventilation in four different groups of BALB/c mice. A cohort of these animals were subjected to an injurious bronchoalveolar lavage before ventilation. The data were analyzed with a single-compartment model that predicts recruitment/derecruitment and tissue distension at each time step in measured pressure-volume loops. We compared several injury cost functions to markers of VILI-induced blood-gas barrier disruption. Of the cost functions considered, we conclude that mechanical power dissipation and strain heterogeneity are the best at distinguishing between graded levels of injury and are good candidates for forecasting the development of VILI. NEW & NOTEWORTHY This work uses a predictive single-compartment model and injury cost functions to assess graded levels of mechanical ventilator-induced lung injury. The most promising measures include strain heterogeneity and mechanical power dissipation.

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