scholarly journals The Kinetics of the Distribution and Breakdown of I131-Albumin in the Rabbit

1959 ◽  
Vol 43 (2) ◽  
pp. 415-444 ◽  
Author(s):  
E. B. Reeve ◽  
J. E. Roberts
Keyword(s):  
Vascular System ◽  
Compartment Model ◽  
Independent Method ◽  
Present Knowledge ◽  
System Model ◽  
Rabbit Plasma ◽  
Plasma Albumin ◽  
Model C ◽  
Kinetics Of ◽  
Extravascular Compartment

Rabbit plasma albumin was labelled with I131, injected intravenously, and measurements were made of the radioactivity in plasma, urine, and feces over many days. In some experiments plasma radioactivity was fractionated into I131-albumin activity and that of labelled breakdown products. Curves of these radioactivities were compared with corresponding curves predicted by four mathematical models. Each model included a vascular and extravascular albumin compartment in transfer equilibrium, a radioactive breakdown products compartment, and an excretion compartment; but model A supposed I131-albumin catabolism to occur within the vascular system, model B within the extravascular compartment, model C within both, and model D within a separate compartment receiving albumin for catabolism from the plasma. The experimental data were reasonably well predicted by models A and C. However, model D, though data were insufficient for its complete validation, gave the best predictions and agrees with present knowledge of albumin catabolism. Various methods for calculating the rate of albumin breakdown are discussed. When calculations are based solely on the plasma radioactivity data, identical rates are predicted by models A, C, and D. When, as a valuable independent method, catabolism is calculated from plasma and excreted radioactivities, an error (ordinarily small) is incurred unless account is taken of the rate of passage of I131-albumin to the breakdown sites, and of the rate of excretion of the radioactive breakdown products.

Kinetics of Vascular and Extravascular Protein Exchange in Unbled and Bled Dogs

1955 ◽  
Vol 184 (1) ◽  
pp. 175-182 ◽  
Author(s):  
Karlman Wasserman ◽  
Jeanne D. Joseph ◽  
H. S. Mayerson
Keyword(s):  
Specific Activity ◽  
Blood Stream ◽  
Separate Entity ◽  
Approach To Equilibrium ◽  
Plasma Albumin ◽  
Compartment System ◽  
Specific Activities ◽  
Almost All ◽  
Kinetics Of ◽  
Extravascular Compartment

Unanesthetized, healthy greyhounds were infused with 25% albumin or bled, injected with I131-labeled albumin and albumin specific activities determined. It is shown that the albumin specific activity curves can be altered by changing the ratio of the vascular to extravascular albumin masses in a manner predicted from the mathematics of a two-compartment system. Increase of vascular albumin mass relative to extravascular mass results in a smaller initial disappearance of albumin specific activity from the blood stream and a faster approach to equilibrium. Decrease of vascular albumin mass relative to extravascular mass by bleeding shows that 50% of albumin replacement after hemorrhage appears to be accomplished within 24 hours. Almost all of this protein comes from the extravascular compartment. Rapid anabolism accounts for the replenishment of protein for the next 2–5 days, during and after which there is a reduced catabolism of the existing plasma albumin. The results indicate that an extravascular albumin mass exists as a separate entity and net movements may occur from this mass into the plasma when the equilibrium between the vascular and extravascular masses is disturbed.

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.

scholarly journals The SEIS model, or, the contact process with a latent stage

2016 ◽  
Vol 53 (3) ◽  
pp. 783-801 ◽  
Author(s):  
Eric Foxall
Keyword(s):  
Particle System ◽  
Contact Process ◽  
Compartment Model ◽  
Spatial Dimension ◽  
Critical Values ◽  
System Model ◽  
Upper And Lower Bounds ◽  
Latent Stage ◽  
Latent Time ◽  
The Moment

AbstractThe susceptible→exposed→infectious→susceptible (SEIS) model is well known in mathematical epidemiology as a model of infection in which there is a latent period between the moment of infection and the onset of infectiousness. The compartment model is well studied, but the corresponding particle system has so far received no attention. For the particle system model in one spatial dimension, we give upper and lower bounds on the critical values, prove convergence of critical values in the limit of small and large latent time, and identify a limiting process to which the SEIS model converges in the limit of large latent time.

Disposition Kinetics of Disopyramide in Human Healthy Volunteers Described by an Open Three Compartment Model

1989 ◽  
Vol 64 (5) ◽  
pp. 412-416 ◽  
Author(s):  
Jan Bonde ◽  
Niels Melchior Jensen ◽  
Lars E. Pedersen ◽  
Helle R. Angelo ◽  
Seren N. Rasmussen ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Compartment Model ◽  
Disposition Kinetics ◽  
Three Compartment Model ◽  
Kinetics Of

scholarly journals Kinetic Modelling of [68Ga]Ga-DOTA-Siglec-9 in Porcine Osteomyelitis and Soft Tissue Infections

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4094 ◽  
Author(s):  
Lars Jødal ◽  
Anne Roivainen ◽  
Vesa Oikonen ◽  
Sirpa Jalkanen ◽  
Søren B. Hansen ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Hind Limb ◽  
Kinetic Modelling ◽  
Compartment Model ◽  
Cell Surface Expression ◽  
Soft Tissue Infections ◽  
Tissue Samples ◽  
Tissue Compartment ◽  
Arterial Blood ◽  
Kinetics Of

Background: [68Ga]Ga-DOTA-Siglec-9 is a positron emission tomography (PET) radioligand for vascular adhesion protein 1 (VAP-1), a protein involved in leukocyte trafficking. The tracer facilitates the imaging of inflammation and infection. Here, we studied the pharmacokinetic modelling of [68Ga]Ga-DOTA-Siglec-9 in osteomyelitis and soft tissue infections in pigs. Methods: Eight pigs with osteomyelitis and soft tissue infections in the right hind limb were dynamically PET scanned for 60 min along with arterial blood sampling. The fraction of radioactivity in the blood accounted for by the parent tracer was evaluated with radio-high-performance liquid chromatography. One- and two-tissue compartment models were used for pharmacokinetic evaluation. Post-mortem soft tissue samples from one pig were analysed with anti-VAP-1 immunofluorescence. In each analysis, the animal’s non-infected left hind limb was used as a control. Results: Tracer uptake was elevated in soft tissue infections but remained low in osteomyelitis. The kinetics of [68Ga]Ga-DOTA-Siglec-9 followed a reversible 2-tissue compartment model. The tracer metabolized quickly; however, taking this into account, produced more ambiguous results. Infected soft tissue samples showed endothelial cell surface expression of the Siglec-9 receptor VAP-1. Conclusion: The kinetics of [68Ga]Ga-DOTA-Siglec-9 uptake in porcine soft tissue infections are best described by the 2-tissue compartment model.

Kinetics of dodecanedioic acid triglyceride in rats

1999 ◽  
Vol 276 (3) ◽  
pp. E497-E502
Author(s):  
A. de Gaetano ◽  
G. Mingrone ◽  
M. Castagneto ◽  
G. Benedetti ◽  
A. V. Greco ◽  
...  
Keyword(s):  
High Performance ◽  
Compartment Model ◽  
High Performance Liquid Chromatographic ◽  
Volume Of Distribution ◽  
Peripheral Compartment ◽  
Parameter Estimates ◽  
Tissue Uptake ◽  
Male Wistar Rats ◽  
Dodecanedioic Acid ◽  
Kinetics Of

The kinetics of the triglyceride of dodecanedioic acid (TGDA) has been investigated in 30 male Wistar rats after a rapid intravenous bolus injection. TGDA and its product of hydrolysis, nonesterified dodecanedioic acid (NEDA), were measured in plasma samples taken at different times using an improved high-performance liquid chromatographic method. The 24-h urinary excretion of TGDA was 1.54 ± 0.37 μmol, corresponding to ∼0.67% of the administered amount. Several kinetics models were considered, including central and peripheral compartments for the triglyceride and the free forms and expressing transports between compartments with combinations of linear, carrier-limited, or time-varying mechanisms. The parameter estimates of the kinetics of TGDA and of NEDA were finally obtained using a three-compartment model in which the transfer of TGDA to NEDA was assumed to be linear, through a peripheral compartment, and the tissue uptake of NEDA was assumed to be carrier limited. TGDA had a large volume of distribution (∼0.5 l/kg body wt) with a fast disappearance rate from plasma (0.42 min−1), whereas NEDA had a very small volume of distribution (∼0.04 l/kg body wt) and a tissue uptake with maximal transport rate of 0.636 mM/min. In conclusion, this first study on the triglyceride form of dodecanedioic acid indicates that it is rapidly hydrolyzed and that both triglyceride and nonesterified forms are excreted in the urine to a very low extent. The tissue uptake rate of NEDA is consistent with the possibility of achieving substantial energy delivery, should it be added to parenteral nutrition formulations. Furthermore, the amount of sodium administered with the triglyceride form is one-half of that necessary with the free diacid.

scholarly journals O09 Drug delivery kinetics of intravenous gentamicin in a population of neonates

2019 ◽  
Vol 104 (6) ◽  
pp. e4.2-e4
Author(s):  
G Salis ◽  
N Medlicott ◽  
D Reith
Keyword(s):  
Drug Delivery ◽  
Time Lag ◽  
Medical Science ◽  
Compartment Model ◽  
Pharmacokinetic Parameters ◽  
List Type ◽  
First Order ◽  
Model Drug ◽  
The Individual ◽  
Kinetics Of

BackgroundGentamicin is commonly used in the NICU setting and is often administered via long lines, which increases variability in the rate of administration. We aimed to model drug delivery pharmacokinetic parameters for intravenous gentamicin administered via umbilical venous catheters (UVCs).MethodsData was modelled from infusion simulations of gentamicin delivery using UVCs with a background flow rate of 0.5 ml/h.1 Different combinations of dose (2 mg, 5 mg) were given by bolus injection over 3–5 minutes, followed by a normal saline flush (1 ml, 2 ml). Gentamicin levels were measured at 5 minute intervals over an hour via high pressure liquid chromatography.Phoenix Certara (version 8.1) was used for modelling. An extravascular model with clearance removed was used to predict parameters: absorption constant (Ka), time lag (Tlag), and bioavailability (F). F was used to enable an estimate of the variability in dose administered. Different error models were tested to ascertain which best described the data.ResultsAn extravascular one compartment model with first order absorption and additive error best described the data. Estimates for the model with a 2 mg dose and 1 ml flush were Ka 0.34L/min, Tlag 1.28min, F 0.97, standard deviation (stdev) 0.14. For 2 mg, 2 ml flush, estimates were Ka 0.86L/min, Tlag 3.01min, F 0.87, stdev 0.01. For 5 mg, 1 ml flush, estimates were Ka 0.48L/min, Tlag 3.13min, F 1.03, stdev 0.12. For 5 mg, 2 ml flush, estimates were Ka 0.83L/min, Tlag 3.29min, F 1.09, stdev 0.02. For each model epsshrinkage and nshrinkage for Tlag and F were low, however nshrinkage for ka was 0.9999.ConclusionThis is the first known modelling of gentamicin delivery kinetics. The studies all had high nshrinkage for Ka, therefore the individual estimates of ka may be unreliable. Further studies with a higher number of replicates would provide more favourable data for estimating Ka.ReferenceLala AC ( 2016). Variability in neonatal gentamicin administration influencing drug delivery kinetics (Thesis, Master of Medical Science). University of Otago.Disclosure(s)No conflict of interest declared. Funding for research via the Freemasons Society of New Zealand.

Effects of age and fasting on gluconeogenesis from glycerol in dogs

1976 ◽  
Vol 230 (2) ◽  
pp. 362-367 ◽  
Author(s):  
SE Hall ◽  
AJ Hall ◽  
RA Layberry ◽  
M Berman ◽  
G Hetenyi
Keyword(s):  
Glucose Production ◽  
Compartment Model ◽  
Glycerol Production ◽  
Glucose Carbon ◽  
Kinetics Of

The extent of gluconeogenesis from glycerol was examined in pups and adult dogs. With use of the SAAM-26 program, a four compartment model was formulated from tracer data to calculate the kinetics of the glycerol:glucose system. In the postabsorptive state gluconeogenesis from glycerol declines with age: 13.8% of glucose carbon originated from glycerol in 0- to 4-day-old pups, 6% in adults. Approximately 50% of glycerol carbon is converted to glucose carbon independent of age. During fasting, a) the percentage of glucose carbon arising from glycerol carbon increased to 13.3% and 10.3% in adult dogs and pups 5-19 days old, respectively, in younger pups it declined to 3.4%; b) glycerol production increased in adults, but decreased in the youngest pups; c) glucose production and utilization decreased at all ages, and a smaller percentage of glycerol carbon was converted to glucose carbon, especially in the youngest pups. Thus in neonates fasting decreases gluconeogenesis from glycerol.

Intertissue diffusion effect for inert fat-soluble gases

1965 ◽  
Vol 20 (4) ◽  
pp. 621-627 ◽  
Author(s):  
William Perl ◽  
Herbert Rackow ◽  
Ernest Salanitre ◽  
Gerald L. Wolf ◽  
Robert M. Epstein
Keyword(s):  
Adipose Tissue ◽  
Gas Exchange ◽  
Human Subjects ◽  
Compartment Model ◽  
Inert Gases ◽  
Gas Uptake ◽  
Model Generalization ◽  
Capillary Exchange ◽  
Uptake Measurement ◽  
Kinetics Of

An approximately constant 5% difference in alveolar concentration of nitrous oxide and cyclopropane exists when these two gases are administered simultaneously to human subjects. This difference in uptake cannot be fully explained within the traditional framework of a perfusion-limited, multi-compartment model of inert gas exchange. It is proposed that this difference reflects direct diffusion from lean to neighboring adipose tissue through distances of the order of 1 mm. The diffusional rate of cyclopropane uptake into adipose tissue is initially large relative to perfusional uptake. The two rates eventually become and remain comparable as both decrease to zero. Implications of these results for deduction of blood flow to body adipose tissue by gas uptake measurement, and for utilization of capillary exchange surface by fat-soluble gases in adipose tissue are discussed. compartment model generalization; gas uptake in body; inert, fat-soluble gas uptake; kinetics of gas exchange in body; body uptake of inert gases; fat-soluble gas uptake; distribution kinetics of gases in body Submitted on February 3, 1964

Kinetics of transepithelial movement of heavy metals in rat jejunum

1987 ◽  
Vol 253 (2) ◽  
pp. G134-G138
Author(s):  
E. C. Foulkes ◽  
D. M. McMullen
Keyword(s):  
Heavy Metals ◽  
Venous Blood ◽  
Compartment Model ◽  
Intestinal Lumen ◽  
Rat Jejunum ◽  
Temperature Dependent ◽  
Appearance Time ◽  
Portal Venous Blood ◽  
Kinetics Of

The kinetics of the transepithelial movement of heavy metals were studied in the perfused rat jejunum in situ. The peak appearance time (TET) of Zn, Ni, and Cd in portal venous blood was determined after their transient (10 s) introduction into the intestinal lumen. Observed TET values for these metals were positively correlated with their affinities for metallothionein and agreed with those predicted on the basis of a linear three-compartment model that does not allow for paracellular pathways. Further evidence was provided to support the hypothesis that Cd absorption consists first of Cd binding to negative membrane charges followed by a temperature-dependent internalization step.

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