Energy nutrients modulate the splanchnic sequestration of dietary nitrogen in humans: a compartmental analysis

2001 ◽  
Vol 281 (2) ◽  
pp. E248-E260 ◽  
Author(s):  
H. Fouillet ◽  
C. Gaudichon ◽  
F. Mariotti ◽  
C. Bos ◽  
J. F. Huneau ◽  
...  
Keyword(s):  
Compartmental Model ◽  
Compartmental Analysis ◽  
Dietary Nitrogen ◽  
Amino Acid Availability ◽  
Nutritional Conditions ◽  
Dietary Amino Acid ◽  
Single Meal ◽  
Peripheral Areas ◽  
Kinetics Of ◽  
Insight Into

We used a previously developed compartmental model to assess the postprandial distribution and metabolism of dietary nitrogen (N) in the splanchnic and peripheral areas after the ingestion of a single meal containing milk protein either alone (MP) or with additional sucrose (SMP) or fat (FMP). The addition of fat was predicted to enhance splanchnic dietary N anabolism only transiently, without significantly affecting the global kinetics of splanchnic retention and peripheral uptake. In contrast, the addition of sucrose, which induced hyperinsulinemia, was predicted to enhance dietary N retention and anabolism in the splanchnic bed, thus leading to reduced peripheral dietary amino acid availability and anabolism. The incorporation of dietary N into splanchnic proteins was thus predicted to reach 18, 24, and 35% of ingested N 8 h after MP, FMP, and SMP, respectively. Such a model provides insight into the dynamics of the system in the nonsteady postprandial state and constitutes a useful, explanatory tool to determine the region-specific utilization of dietary N under different nutritional conditions.

scholarly journals The Kinetics of Sodium Transport in the Toad Bladder

1971 ◽  
Vol 57 (3) ◽  
pp. 326-348 ◽  
Author(s):  
Arthur L. Finn ◽  
Maxine L. Rockoff
Keyword(s):  
Sodium Transport ◽  
Compartmental Model ◽  
Compartmental Analysis ◽  
Dry Weight ◽  
Sodium Content ◽  
Toad Bladder ◽  
Sums Of Exponentials ◽  
Kinetics Of ◽  
Total Tissue ◽  
Tissue Sodium

A compartmental model of toad bladder sodium content has been developed, whereby it is possible to measure the four unidirectional fluxes across the opposite faces of the transport compartment, as well as the amount of sodium in the compartment. 24Na is added to the mucosal medium of a short-circuited bladder mounted between halves of a chamber in which the fluid is stirred by rotating impellers. After a steady state is reached, nonradioactive medium is flushed through both sides of the chamber, collected, and counted. The data from each chamber are fitted to sums of exponentials and interpreted in terms of conventional compartmental analysis. Three exponentials are required, with half-times of 0.2, 2.2, and 14.0 min. It is shown that the first of these represents chamber washout, the second the transport pool, and the third a tissue compartment which is not involved in active sodium transport and which does not communicate with the transport pool. The second compartment contains 10.5 µEq of sodium per 100 mg dry weight, an amount equal to approximately 30% of total tissue sodium. The results also indicate, as expected from electrophysiological data, that the mucosal-facing side of the transport compartment is over 10 times as permeable to sodium as the serosal, or pump, side.

Kinetics of copper metabolism in rats: a compartmental model

1991 ◽  
Vol 261 (1) ◽  
pp. E115-E125
Author(s):  
M. A. Dunn ◽  
M. H. Green ◽  
R. M. Leach
Keyword(s):  
Compartmental Model ◽  
Copper Metabolism ◽  
Compartmental Analysis ◽  
Whole Body ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Hypothesis Model ◽  
Extrahepatic Tissues ◽  
Intracellular Metabolism ◽  
Kinetics Of

odel-based compartmental analysis was used to describe data on the whole body kinetics of copper metabolism in rats. Data were collected on recovery of radio-copper in plasma, liver, skin, skeletal muscle, bile, and feces for 3 days after the injection of 10 micrograms iv of copper labeled with 64Cu. Data on copper masses and on 64Cu kinetics were analyzed by the stimulation, analysis, and modeling computer programs. Observed data were fit to a 16-component “working hypothesis” model; fractional transfer coefficients were estimated, and steady-state compartment masses and copper transfer rates were calculated. The model postulates a rapid turnover of plasma nonceruloplasmin (NCp) copper (8.5 h-1), which exchanged a large amount of copper with extrahepatic tissues (16 micrograms/h) as well as liver (13 micrograms/h). In comparison, ceruloplasmin (Cp) transferred relatively little copper to tissues (less than 1 microgram/h). NCp copper is postulated to be the precursor for biliary copper. Regarding the intracellular metabolism of copper in hepatic and extrahepatic tissues, the data were compatible with a faster turning-over compartment that exchanged copper with NCp and a slower turning-over compartment with input from Cp. In the liver, the slower turning-over compartment was the copper present in peak II (mol mass 30,000–40,000 Da); this received much of its input from the faster turning-over compartment (peak III), which was hypothesized to represent, in large part, copper in metallothionein.

scholarly journals Rapid systemic surge of IL-33 after severe human trauma: a prospective observational study

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Olav Sundnes ◽  
William Ottestad ◽  
Camilla Schjalm ◽  
Peter Lundbäck ◽  
Lars la Cour Poulsen ◽  
...  
Keyword(s):  
High Resolution ◽  
Prospective Observational Study ◽  
Tissue Injury ◽  
Trauma Patients ◽  
Decoy Receptor ◽  
Interleukin 33 ◽  
Injured Patients ◽  
First Time ◽  
Kinetics Of ◽  
Insight Into

Abstract Background Alarmins are considered proximal mediators of the immune response after tissue injury. Understanding their biology could pave the way for development of new therapeutic targets and biomarkers in human disease, including multiple trauma. In this study we explored high-resolution concentration kinetics of the alarmin interleukin-33 (IL-33) early after human trauma. Methods Plasma samples were serially collected from 136 trauma patients immediately after hospital admission, 2, 4, 6, and 8 h thereafter, and every morning in the ICU. Levels of IL-33 and its decoy receptor sST2 were measured by immunoassays. Results We observed a rapid and transient surge of IL-33 in a subset of critically injured patients. These patients had more widespread tissue injuries and a greater degree of early coagulopathy. IL-33 half-life (t1/2) was 1.4 h (95% CI 1.2–1.6). sST2 displayed a distinctly different pattern with low initial levels but massive increase at later time points. Conclusions We describe for the first time early high-resolution IL-33 concentration kinetics in individual patients after trauma and correlate systemic IL-33 release to clinical data. These findings provide insight into a potentially important axis of danger signaling in humans.

scholarly journals Simulation of Folding Kinetics for Aligned RNAs

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 347
Author(s):  
Jiabin Huang ◽  
Björn Voß
Keyword(s):  
Evolutionary Conservation ◽  
Folding Kinetics ◽  
New Approach ◽  
Computational Approaches ◽  
Reasonable Time ◽  
Valuable Method ◽  
Kinetics Of ◽  
Insight Into ◽  
Folding Space ◽  
Standing Problem

Studying the folding kinetics of an RNA can provide insight into its function and is thus a valuable method for RNA analyses. Computational approaches to the simulation of folding kinetics suffer from the exponentially large folding space that needs to be evaluated. Here, we present a new approach that combines structure abstraction with evolutionary conservation to restrict the analysis to common parts of folding spaces of related RNAs. The resulting algorithm can recapitulate the folding kinetics known for single RNAs and is able to analyse even long RNAs in reasonable time. Our program RNAliHiKinetics is the first algorithm for the simulation of consensus folding kinetics and addresses a long-standing problem in a new and unique way.

Atomic-level insight into reasonable design of metal-based catalysts for hydrogen oxidation in alkaline electrolytes

2021 ◽  
Author(s):  
Lulu An ◽  
Xu Zhao ◽  
Tonghui Zhao ◽  
Deli Wang
Keyword(s):  
Fuel Cell ◽  
Anion Exchange ◽  
Hydrogen Oxidation ◽  
Anion Exchange Membrane ◽  
Atomic Level ◽  
Alkaline Electrolytes ◽  
Exchange Membrane ◽  
Kinetics Of ◽  
Insight Into ◽  
Hydrogen Utilization

Anion exchange membrane fuel cell (AEMFC) is becoming highly attractive for hydrogen utilization owing to the advantages of employing economic catalysts in alkaline electrolytes. Nevertheless, the kinetics of anodic hydrogen...

An Insight into the Mechanism and Kinetics of Reactions In BOF Steelmaking: Theory vs Practice

2010 ◽  
Vol 81 (11) ◽  
pp. 940-948 ◽  
Author(s):  
A. K. Shukla ◽  
B. Deo ◽  
S. Millman ◽  
B. Snoeijer ◽  
A. Overbosch ◽  
...  
Keyword(s):  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Insight Into

Kinetics of retinyl esters during postprandial lipemia in man: A compartmental model

Metabolism ◽  
1997 ◽  
Vol 46 (5) ◽  
pp. 584-594 ◽  
Author(s):  
Ngoc-Anh Le ◽  
Paul M. Coates ◽  
Paul R. Gallagher ◽  
Jean A. Cortner
Keyword(s):  
Compartmental Model ◽  
Postprandial Lipemia ◽  
Retinyl Esters ◽  
Kinetics Of

scholarly journals Dynamics of Tpm1.8 domains on actin filaments with single molecule resolution

2020 ◽  
Author(s):  
Ilina Bareja ◽  
Hugo Wioland ◽  
Miro Janco ◽  
Philip R. Nicovich ◽  
Antoine Jégou ◽  
...  
Keyword(s):  
Actin Filament ◽  
Single Molecule ◽  
Actin Filaments ◽  
High Probability ◽  
Actin Binding ◽  
Single Molecule Level ◽  
Filament Dynamics ◽  
Kinetics Of ◽  
Insight Into

ABSTRACTTropomyosins regulate dynamics and functions of the actin cytoskeleton by forming long chains along the two strands of actin filaments that act as gatekeepers for the binding of other actin-binding proteins. The fundamental molecular interactions underlying the binding of tropomyosin to actin are still poorly understood. Using microfluidics and fluorescence microscopy, we observed the binding of fluorescently labelled tropomyosin isoform Tpm1.8 to unlabelled actin filaments in real time. This approach in conjunction with mathematical modeling enabled us to quantify the nucleation, assembly and disassembly kinetics of Tpm1.8 on single filaments and at the single molecule level. Our analysis suggests that Tpm1.8 decorates the two strands of the actin filament independently. Nucleation of a growing tropomyosin domain proceeds with high probability as soon as the first Tpm1.8 molecule is stabilised by the addition of a second molecule, ultimately leading to full decoration of the actin filament. In addition, Tpm1.8 domains are asymmetrical, with enhanced dynamics at the edge oriented towards the barbed end of the actin filament. The complete description of Tpm1.8 kinetics on actin filaments presented here provides molecular insight into actin-tropomyosin filament formation and the role of tropomyosins in regulating actin filament dynamics.

Revisiting graphene–polymer nanocomposite for enhancing anticorrosion performance: a new insight into interface chemistry and diffusion model

Nanoscale ◽  
2018 ◽  
Vol 10 (26) ◽  
pp. 12612-12624 ◽  
Author(s):  
Dipak Dutta ◽  
Andita Nataria Fitri Ganda ◽  
Jui-Kung Chih ◽  
Cheng-Chun Huang ◽  
Chung-Jen Tseng ◽  
...  
Keyword(s):  
Galvanic Corrosion ◽  
Polymer Nanocomposite ◽  
Diffusion Kinetics ◽  
Interfacial Chemistry ◽  
Interface Chemistry ◽  
Graphene Nanocomposite ◽  
Kinetics Of ◽  
And Diffusion ◽  
Insight Into ◽  
Percolation Network

The interfacial chemistry and diffusion kinetics of a polymer–graphene nanocomposite anticorrosion coating were studied to minimize galvanic corrosion facilitated by the formation of an interconnected graphene percolation network.

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