A Mathematical Treatment of Multiple Intermittent Intravenous Infusions in a One-Compartment Model

2021 ◽  
pp. 106103
Author(s):  
Michalakis Savva
Keyword(s):  
Compartment Model ◽  
Mathematical Treatment ◽  
Intravenous Infusions

The Effect on Appetite in Dogs of Pyrogenic Substances in Intravenous Infusions

1954 ◽  
Vol 27 (3) ◽  
pp. 347-352 ◽  
Author(s):  
W.M. Dale Beamer ◽  
J.E. Thomas ◽  
Beatrice Moore
Keyword(s):  
Intravenous Infusions

Influence of stable iodine on the uptake of the thyroid – model vs. experiment

2001 ◽  
Vol 40 (01) ◽  
pp. 31-37 ◽  
Author(s):  
U. Wellner ◽  
E. Voth ◽  
H. Schicha ◽  
K. Weber
Keyword(s):  
Time Course ◽  
Compartment Model ◽  
The Body ◽  
Iodine Uptake ◽  
Model Calculations ◽  
Physiological Conditions ◽  
Iodine Supply ◽  
Predicted Values ◽  
The Individual ◽  
Stable Iodine

Summary Aim: The influence of physiological and pharmacological amounts of iodine on the uptake of radioiodine in the thyroid was examined in a 4-compartment model. This model allows equations to be derived describing the distribution of tracer iodine as a function of time. The aim of the study was to compare the predictions of the model with experimental data. Methods: Five euthyroid persons received stable iodine (200 μg, 10 mg). 1-123-uptake into the thyroid was measured with the Nal (Tl)-detector of a body counter under physiological conditions and after application of each dose of additional iodine. Actual measurements and predicted values were compared, taking into account the individual iodine supply as estimated from the thyroid uptake under physiological conditions and data from the literature. Results: Thyroid iodine uptake decreased from 80% under physiological conditions to 50% in individuals with very low iodine supply (15 μg/d) (n = 2). The uptake calculated from the model was 36%. Iodine uptake into the thyroid did not decrease in individuals with typical iodine supply, i.e. for Cologne 65-85 μg/d (n = 3). After application of 10 mg of stable iodine, uptake into the thyroid decreased in all individuals to about 5%, in accordance with the model calculations. Conclusion: Comparison of theoretical predictions with the measured values demonstrated that the model tested is well suited for describing the time course of iodine distribution and uptake within the body. It can now be used to study aspects of iodine metabolism relevant to the pharmacological administration of iodine which cannot be investigated experimentally in humans for ethical and technical reasons.

An approach for comparative quantification of myocardial blood flow (0-15-H2O-PET), perfusion (Tc-99m-tetrofosmin-SPECT), and metabolism (F 18-FDG-PET)

2001 ◽  
Vol 40 (05) ◽  
pp. 164-171 ◽  
Author(s):  
B. Nowak ◽  
H.-J. Kaiser ◽  
S. Block ◽  
K.-C. Koch ◽  
J. vom Dahl ◽  
...  
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Fdg Pet ◽  
Model Fitting ◽  
Compartment Model ◽  
Left Ventricular ◽  
Short Axis ◽  
New Approach ◽  
Single Compartment Model ◽  
Tissue Fraction

Summary Aim: In the present study a new approach has been developed for comparative quantification of absolute myocardial blood flow (MBF), myocardial perfusion, and myocardial metabolism in short-axis slices. Methods: 42 patients with severe CAD, referred for myocardial viability diagnostics, were studied consecutively with 0-15-H2O PET (H2O-PET) (twice), Tc-99m-Tetrofosmin 5PECT (TT-SPECT) and F-18-FDG PET (FDG-PET). All dato sets were reconstructed using attenuation correction and reoriented into short axis slices. Each heart was divided into three representative slices (base, rnidventricular, apex) and 18 ROIs were defined on the FDG PET images and transferred to the corresponding H2O-PET and TT-SPECT slices. TT-SPECT and FDG-PET data were normalized to the ROI showing maximum perfusion. MBF was calculated for all left-ventricular ROIs using a single-compartment-model fitting the dynamic H2O-PET studies. Microsphere equivalent MBF (MBF_micr) was calculated by multiplying MBF and tissue-fraction, a parameter which was obtained by fitting the dynamic H2O-PET studies. To reduce influence of viability only well perfused areas (>70% TT-SPECT) were used for comparative quantification. Results: First and second mean global MBF values were 0.85 ml × min-1 × g-1 and 0.84 ml × min-1 × g1, respectively, with a repeatability coefficient of 0.30 ml ÷ min-1 × gl. After sectorization mean MBF_micr was between 0.58 ml × min1 ÷ ml"1 and 0.68 ml × min-1 × ml"1 in well perfused areas. Corresponding TT-SPECT values ranged from 83 % to 91 %, and FDG-PET values from 91 % to 103%. All procedures yielded higher values for the lateral than the septal regions. Conclusion: Comparative quantification of MBF, MBF_micr, TT-SPECT perfusion and FDG-PET metabolism can be done with the introduced method in short axis slices. The obtained values agree well with experimentally validated values of MBF and MBF_micr.

Pharmacokinetics and Effects on Fibrinolytic and Coagulation Parameters of Two Doses of Recombinant Tissue-Type Plasminogen Activator in Healthy Volunteers

1986 ◽  
Vol 56 (01) ◽  
pp. 001-005 ◽  
Author(s):  
M Verstraete ◽  
C A P F Su ◽  
P Tanswell ◽  
W Feuerer ◽  
D Collen
Keyword(s):  
Healthy Volunteers ◽  
Plasminogen Activator ◽  
Degradation Products ◽  
Plasma Concentrations ◽  
State Level ◽  
Compartment Model ◽  
Tissue Type ◽  
Maximum Plasma ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator

SummaryPharmacokinetics and pharmacological effects of two intravenous doses of recombinant tissue-type plasminogen activator (rt-PA) (40 and 60 mg over 90 min) were determined in healthy volunteers. Mean maximum plasma concentrations were 1080 and 1560 ng/ml respectively. The steady state level during subsequent maintenance infusion of 30 mg over 6 h was 250 ng/ml. The pharmacokinetics of rt-PA showed a bi-exponential disappearance from plasma consistent with a 2-compartment model of t½α = 5.7 min, a t½β = 1.3 h and a total clearance of 380 ml/min.Mean fibrinogen levels at the end of the infusions of 40 mg or 60 mg rt-PA over 90 min, measured in thawed plasma samples collected on citrate/aprotinin, decreased to 74% and 57% of the preinfusion values respectively. Plasminogen fell to 55% and 48%, and α2-antiplasmin to 28% and 18% of initial values. No further decrease of these parameters was observed during the infusion of 30 mg rt-PA over 6 h. Only 2% of the preinfusion fibrinogen levels could be recovered as fibrinogen-fibrin degradation products. This moderate extent of systemic fibrinogenolysis is much less than that reported for therapeutic i.v. infusions of streptokinase.

Sustainable Regional Economic Development: Analysis and Management Methods

2020 ◽  
Vol 26 (1) ◽  
pp. 23-34
Author(s):  
B. M. Grinchel’ ◽  
E. A. Nazarova
Keyword(s):  
Economic Development ◽  
Mathematical Treatment ◽  
Mathematical Tool ◽  
Russian Regions ◽  
Regional Economic ◽  
Management Scheme ◽  
Progressive Growth ◽  
Sustainable Regional Development ◽  
High Level ◽  
Development Analysis

The presented study examines methods for analyzing and managing sustainable economic development of Russian regions and possible criteria for assessing and improving sustainability.Aim. The study aims to provide a theoretical and empirical justification for the use of regional competitive attractiveness assessment to manage economic development and improve its sustainability.Tasks. Based on the measurement and analysis of economic competitive attractiveness indicators and their mathematical treatment, the authors assess the sustainability of development of Russian regions in 2013–2017 and the causes of deviations from progressive growth.Methods. This study proposes a mathematical tool for measuring the sustainability of Russian regions by assessing their competitive attractiveness and develops a typology of sustainability in the mathematical space of two variables.Results. Methods for analyzing and managing the sustainability of economic development of Russian regions under the influence of political and economic challenges and risks are proposed. The level and dynamics of regional competitive attractiveness are taken as a criterion of sustainability of economic development. The authors provide methods and indicators for assessing economic competitive attractiveness and criteria for measuring the sustainability of development, which allow them to draw conclusions about the reaction of different regions to the challenges and risks of development in 2013–2017. The study proposes a management scheme for sustainable regional development with a focus on the comprehensive improvement of regional economic competitive attractiveness and potential ways to improve it, including training of municipal and regional managers in crisis management associated with economic and political challenges and risks.Conclusions. Based on the proposed criterion of economic development sustainability and assessment of the competitive attractiveness of regions and their rankings, it is shown that in 2013–2017 45 out of 83 regions were developing sustainably; by 2017, 19 regions out of the 32 that suffered losses in the competitive attractiveness level and rankings in 2015–2016 have managed to restore the sustainability of economic development and their rankings. This study proves that regions with a high level of economic competitive attractiveness show increased sustainability of development.

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