scholarly journals Two approaches to modeling kinetics of biodegradation by growing cells and application of a two-compartment model for mineralization kinetics in sewage.

1986 ◽  
Vol 51 (6) ◽  
pp. 1153-1160 ◽  
Author(s):  
S Simkins ◽  
R Mukherjee ◽  
M Alexander
Keyword(s):  
Compartment Model ◽  
Two Compartment Model ◽  
Mineralization Kinetics ◽  
Kinetics Of

scholarly journals A comparison of the short-term kinetics of zinc metabolism in women during fasting and following a breakfast meal

1998 ◽  
Vol 80 (4) ◽  
pp. 363-370 ◽  
Author(s):  
Nicola M. Lowe ◽  
Leslie R. Woodhouse ◽  
Janet C. King
Keyword(s):  
Energy Content ◽  
Compartment Model ◽  
Zinc Metabolism ◽  
Short Term ◽  
Compartment System ◽  
Breakfast Meal ◽  
Physiological Importance ◽  
Two Compartment Model ◽  
Zn Concentration ◽  
Kinetics Of

The physiological importance and mechanism of the postprandial fall in plasma Zn concentration is not well understood. In order to gain further information on this apparent redistribution of plasma Zn, a stable isotope, 70Zn, was used to study the effect of a breakfast meal on plasma Zn kinetics. Nine women participated in two trials, a fasting trial and a breakfast-meal trial; five of the women participated in a third trial in which the energy content of the breakfast meal was doubled. At each trial, 0.1mg of 70Zn was infused intravenously, and the plasma disappearance of the isotope was analysed using a two-compartment model of Zn kinetics. Plasma Zn concentration fell significantly following the two trials in which the subjects were given meals, reaching low points that were 13 and 19 %, respectively, below concentrations at comparable times during the fasting trial. Kinetic analysis revealed that after the doubled breakfast meal there was a significant fall (P < 0.007) in the size of the most rapidly turning over Zn pool (pool (a)) from 2.90 (se 0.13)mg in the fasting state to 2.47 (se 0.14) mg postprandially. The fractional turnover rate of pool (a) to other extravascular Zn pools, i.e. outside the two-compartment system, was also significantly elevated after the doubled breakfast meal (P < 0.05). These results suggest that the decline in plasma Zn concentration following a meal is due to a redistribution of Zn from the plasma to other more slowly turning over extravascular pools that may be involved in the assimilation and metabolism of fuels following food intake.

Mathematical Modeling of Different Molecule Removal on On-Line Haemodiafiltration: Influence of Dialysis Duration and Infusion Flow

2015 ◽  
Vol 39 (4) ◽  
pp. 288-296 ◽  
Author(s):  
Francisco Maduell ◽  
Juan Sanchez ◽  
Marta Net ◽  
Miquel Gomez ◽  
Jose M. Gonzalez ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Treatment Time ◽  
Compartment Model ◽  
Dialysis Dose ◽  
Β2 Microglobulin ◽  
Dialysis Duration ◽  
Two Compartment Model ◽  
On Line ◽  
The Impact ◽  
Kinetics Of

Background: In a previous study on a nocturnal, every-other-day online haemodiafiltration scheme, different removal patterns were observed for urea, creatinine, β2-​microglobulin, myoglobin and prolactin. The aim of this study was to evaluate the influence of dialysis duration and infusion flow (Qi) on the removal of different molecular weight (MW) solutes, and to quantify the effect of the different treatments on the kinetics of the solutes by using a classical two-compartment model. Methods: This prospective, in-center study was carried out in 10 patients on a nocturnal, every-other-day online post-dilution haemodiafiltration program. Each patient received four dialysis sessions with different conditions, two 4-h sessions (with infusion flows of 50 or 100 ml/min) and two 8-h sessions (with infusion flows of 50 or 100 ml/min). To analyze the solute kinetics, blood samples were obtained hourly during the dialysis treatments and in the first 3 h post-dialysis. Results: Removal patterns differed in the molecules studied, which were quantified by means of the two-compartment mathematical model. The main results show the impact of dialysis duration on the removal of low molecular weight molecules (urea and creatinine), while the impact of Qi is clearly shown for high molecular weight molecules (myoglobin and prolactin). For middle molecular weight solutes, such as β2-microglobulin, both factors (duration and Qi) enhance the removal efficiency of the dialyzer. Conclusions: Our study evaluates experimentally and mathematically how treatment time and infusion flow affect the filtration of solutes of different MW during post-dilution haemodiafiltration. The results provided by the present study should help physicians to select and individualise the most appropriate schedules to deliver an optimum diffusive and convective dialysis dose for each patient.

Influence or age and sex on the kinetics of intravenously administered L-phenylalanine.

1982 ◽  
Vol 28 (1) ◽  
pp. 204-206 ◽  
Author(s):  
R Jagenburg ◽  
C G Regårdh ◽  
S Rödjer
Keyword(s):  
Total Body Clearance ◽  
Kinetic Studies ◽  
Compartment Model ◽  
Peripheral Compartment ◽  
Two Compartment Model ◽  
Total Body ◽  
Kinetics Of ◽  
Effect Of Age ◽  
Age And Sex ◽  
Body Clearance

Abstract We studied the kinetics of intravenously administered L-phenylalanine with respect to the effect of age and sex, using a two-compartment model. We found that the volume of the peripheral compartment and total body clearance decrease with age. The sex-related influence was less obvious when distribution volumes and total body clearance were corrected for differences in body size. We emphasize the necessity of having age-matched control subjects in kinetic studies.

scholarly journals Vitamin E kinetics in sheep

1987 ◽  
Vol 58 (1) ◽  
pp. 113-125 ◽  
Author(s):  
M. Hidiroglou ◽  
K. Karpinski
Keyword(s):  
Vitamin E ◽  
Jugular Vein ◽  
Compartment Model ◽  
The Other ◽  
Intravenous Route ◽  
Biological Availability ◽  
Blood Samples ◽  
Two Compartment Model ◽  
Three Compartment Model ◽  
Kinetics Of

1. Kinetics of physiological doses of D-α-[5-Me-3H]tocopherol(200 μCi) administered to twenty-four sheep were studied using one of four routes: intravenous, oral (capsules), intraruminal and intramuscular.2. Blood samples were withdrawn from the jugular vein periodically for 96 h after the intravenous and oral administrations, for 168 h after the intraruminal administration and for 216 h after the intramuscular administration.3. The study indicated that the biological availability of α-tocopherol followed the order intravenous > intramuscular > oral > intraruminal.4. The rate of elimination was in the order intravenous > oral > intraruminal ˜ intramuscular.5. The intravenous route was fitted with a three-compartment model, whereas the other routes exhibited a good fit for either a one- or two-compartment model.

Kinetics of zinc absorption by the rat jejunum: effects of adrenalectomy and dexamethasone

1983 ◽  
Vol 244 (3) ◽  
pp. G314-G320 ◽  
Author(s):  
R. F. Bonewitz ◽  
E. C. Foulkes ◽  
E. J. O'Flaherty ◽  
V. S. Hertzberg
Keyword(s):  
Compartment Model ◽  
The Body ◽  
Adult Rat ◽  
Two Compartment Model ◽  
65Zn Uptake ◽  
Mathematical Simulations ◽  
Adrenocortical Hormone ◽  
Perfusion Period ◽  
Kinetics Of

Effects of dexamethasone and adrenalectomy on the kinetics of jejunal 65Zn uptake and absorption were studied in the anesthetized adult rat. The jejunal lumen was perfused in situ with 5 mM glucose in 150 mM saline containing 65Zn and [14C]polyethylene glycol as volume marker. Over the 30-min perfusion period, the rate of net 65Zn removal from the perfusate was biexponential due to the establishment of a return flux to the lumen. An open two-compartment model satisfactorily describes these observations: (formula; see text) Dexamethasone (2 mg/kg ip 7 h before perfusion) increased k12 by 75% (P less than 0.0002) and decreased k20 by 45% (P less than 0.04). Both effects were independent of adrenalectomy. Mathematical simulations using the compartmental model and experimentally determined kinetic constants predicted that transfer of 65Zn into the body should be enhanced by adrenalectomy and retarded by dexamethasone administered to adrenalectomized rats. Dexamethasone and adrenalectomy thus differentially affect Zn uptake and absorption in this system, suggesting a possible adrenocortical hormone involvement in the regulation of Zn absorption. These changes are apparently not mediated via metallothionein.

scholarly journals Models for in vivo Kinetic Interactions of Dopamine D2-Neuroreceptors and 3-(2'-[18F]Fluoroethyl)Spiperone Examined with Positron Emission Tomography

1989 ◽  
Vol 9 (6) ◽  
pp. 840-849 ◽  
Author(s):  
Mark M. Bahn ◽  
Sung-Cheng Huang ◽  
Randall A. Hawkins ◽  
Nagichettiar Satyamurthy ◽  
John M. Hoffman ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Nonlinear Model ◽  
Compartment Model ◽  
Emission Tomography ◽  
Positron Emission ◽  
Two Compartment Model ◽  
Model Configuration ◽  
Net Uptake ◽  
Kinetics Of

The in vivo tracer kinetics of 3-(2apos;-[18F]fluoroethyl)spiperone (FESP) in the caudate/striatum and cerebellar regions of the human and monkey brain were studied with positron emission tomography (PET). The minimal model configuration that can describe the kinetics was determined statistically. Three two-compartment model configurations were found to be suitable for describing the kinetics in caudate/striatum and cerebellum: (1) a nonlinear model (five parameters) applicable to studies using nontracer (partially saturating) quantities of FESP in monkey striatum, (2) a linear four-parameter model applicable to the caudate/striatal and cerebellar kinetics in human and monkey studies with tracer quantities of FESP, and (3) a linear three-parameter model derived from the four-parameter model by assuming irreversible binding applicable to tracer studies of the human caudate. In the human studies, when the caudate kinetics ( n = 4) were fit by model 2 (with four parameters), the value of the in vivo ligand dissociation constant kd was found to be 0.0015 ± 0.0032/min. The three-parameter model (model 3) was found to fit the data equally well; this model is equivalent to model 2 with kd set to zero. In the monkey studies, it was found that for short (90 min) studies using tracer quantities of FESP, model 2 fit the striatal kinetics better than model 3. The parameters estimated using model 2 (four parameters) were in better agreement with those estimated by the nonlinear model (model 1) than those estimated using model 3 (three parameters). The use of a graphical approach gives estimates of the plasma–tissue fractional transport rate constant K1 and the net uptake constant K3 comparable to estimates using model 3 for both human and monkey studies.

scholarly journals Isotopic and modeling investigation of long-term protein turnover in rat tissues

2013 ◽  
Vol 304 (3) ◽  
pp. R218-R231 ◽  
Author(s):  
Nathalie Poupin ◽  
Jean-François Huneau ◽  
François Mariotti ◽  
Daniel Tomé ◽  
Cécile Bos ◽  
...  
Keyword(s):  
Compartment Model ◽  
Rat Tissues ◽  
Product Model ◽  
New Approach ◽  
Two Compartment Model ◽  
Fractional Synthesis ◽  
Tracer Methods ◽  
Kidney Liver ◽  
Kinetics Of

Fractional synthesis rates (FSR) of tissue proteins (P) are usually measured using labeled amino acid (AA) tracer methods over short periods of time under acute, particular conditions. By combining the long-term and non-steady-state 15N labeling of AA and P tissue fractions with compartmental modeling, we have developed a new isotopic approach to investigate the degree of compartmentation of P turnover in tissues and to estimate long-term FSR values under sustained and averaged nutritional and physiological conditions. We measured the rise-to-plateau kinetics of nitrogen isotopic enrichments (δ15N) in the AA and P fractions of various tissues in rats for 2 mo following a slight increase in diet δ15N. Using these δ15N kinetics and a numerical method based on a two-compartment model, we determined reliable FSR estimates for tissues in which P turnover is adequately represented by such a simple precursor-product model. This was the case for kidney, liver, plasma, and muscle, where FSR estimates were 103, 101, 58, and 11%/day, respectively. Conversely, we identified tissues, namely, skin and small intestine, where P turnover proved to be too complex to be represented by a simple two-compartment model, evidencing the higher level of subcompartmentation of the P and/or AA metabolism in these tissues. The present results support the value of this new approach in gaining cognitive and practical insights into tissue P turnover and propose new and integrated FSR values over all individual precursor AA and all diurnal variations in P kinetics.

Kinetics of nortriptyline in man according to a two compartment model

1975 ◽  
Vol 8 (5) ◽  
pp. 343-347 ◽  
Author(s):  
K. Fredricson Over� ◽  
L. F. Gram ◽  
V. Hansen
Keyword(s):  
Compartment Model ◽  
Two Compartment Model ◽  
Kinetics Of

Two-Compartment Model of Cholesterol Kinetics for Establishment of Treatment Strategy of LDL Apheresis in Nephrotic Hypercholesterolemia

1994 ◽  
Vol 12 (6) ◽  
pp. 317-326 ◽  
Author(s):  
Masatomo Yashiro ◽  
Eri Muso ◽  
Munehiro Matsushima ◽  
Ryoichi Nagura ◽  
Kenji Sawanishi ◽  
...  
Keyword(s):  
Treatment Strategy ◽  
Compartment Model ◽  
Ldl Apheresis ◽  
Two Compartment Model

Clearance and Non-Invasive Determination of the Hepatic Extraction of Indocyanine Green in Baboons and Man

1983 ◽  
Vol 64 (2) ◽  
pp. 207-212 ◽  
Author(s):  
S. L. Grainger ◽  
P. W. N. Keeling ◽  
I. M. H. Brown ◽  
J. H. Marigold ◽  
R. P. H. Thompson
Keyword(s):  
Indocyanine Green ◽  
Accurate Determination ◽  
Liver Blood Flow ◽  
Compartment Model ◽  
Hepatic Extraction ◽  
Non Invasive ◽  
Two Compartment Model ◽  
Hepatic Extraction Ratio ◽  
Plasma Disappearance Curve

1. The disposition of an intravenous bolus of indocyanine green (ICG) has been studied in healthy man and baboons using a novel analysis of a two compartment pharmacokinetic model. 2. This analysis enabled the hepatic extraction ratio (ER) of dye to be determined solely from the plasma disappearance curve, and the ER determined did not differ from that measured by hepatic vein catheterization. 3. When compared with clearance measured at steady state, the two compartment model gave a significantly more accurate determination of plasma clearance than did the conventional one compartment model. 4. It is concluded that, in health, liver blood flow may be calculated accurately and noninvasively after a single intravenous injection of ICG.

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