Rate of erythropoietin formation in humans in response to acute hypobaric hypoxia

This study was carried out to investigate the early changes in erythropoietin (EPO) formation in humans in response to hypoxia. Six volunteers were exposed to simulated altitudes of 3,000 and 4,000 m in a decompression chamber for 5.5 h. EPO was measured by radioimmunoassay in serum samples withdrawn every 30 min during altitude exposure and also in two subjects after termination of hypoxia (4,000 m). EPO levels during hypoxia were significantly elevated after 114 and 84 min (3,000 and 4,000 m), rising thereafter continuously for the period investigated. Mean values increased from 16.0 to 22.5 mU/ml (3,000 m) and from 16.7 to 28.0 mU/ml (4,000 m). This rise in EPO levels corresponds to 1.8-fold (3,000 m) and 3.0-fold (4,000 m) increases in the calculated production rate of the hormone. After termination of hypoxia, EPO levels continued to rise for approximately 1.5 h and after 3 h declined exponentially with an average half-life time of 5.2 h.

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Antihypoxic activity of the VMA-10-18 derivate under hypobaric hypoxia in mice

Archiv Euromedica ◽

10.35630/2199-885x/2020/10/4.6 ◽

2020 ◽

Vol 10 (4) ◽

pp. 29-30

Author(s):

Anastasia Gerashchenko ◽

Natalia Shabanova ◽

Andrey Voronkov

Keyword(s):

Hypobaric Hypoxia ◽

Life Time ◽

Test Site ◽

Control Group ◽

Antihypoxic Activity ◽

Acute Hypobaric Hypoxia ◽

Reference Drug

The present study was carried out to evaluate the effect of a new derivative VMA-10-18 (10 mg/kg) on the resistance of mice to acute hypobaric hypoxia. It was confirmed that the studied derivative contributes to an increase in the life time on the lethal test site by 2,7 times (p <0,05) compared with the control group of animals and exceeds the strength of the effect of the reference drug Metaprot by 1,2 (p <0,05).

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Covalent Complexes Between Low Molecular Weight Heparin Fragments and Antithrombin III – Inhibition Kinetics and Turnover Parameters

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657333 ◽

1983 ◽

Vol 49 (02) ◽

pp. 109-115 ◽

Cited By ~ 4

Author(s):

M Hoylaerts ◽

E Holmer ◽

M de Mol ◽

D Collen

Keyword(s):

Molecular Weight ◽

Half Life ◽

Low Molecular Weight Heparin ◽

Antithrombin Iii ◽

Factor Xa ◽

Life Time ◽

Low Molecular Weight ◽

High Affinity ◽

Plasma Half Life ◽

Covalent Complex

SummaryTwo high affinity heparin fragments (A/r 4,300 and M, 3,200) were covalently coupled to antithrombin III (J. Biol. Chem. 1982; 257: 3401-3408) with an apparent 1:1 stoichiometry and a 30-35% yield.The purified covalent complexes inhibited factor Xa with second order rate constants very similar to those obtained for antithrombin III saturated with these heparin fragments and to that obtained for the covalent complex between antithrombin III and native high affinity heparin.The disappearance rates from plasma in rabbits of both low molecular weight heparin fragments and their complexes could adequately be represented by two-compartment mammillary models. The plasma half-life (t'/j) of both low Afr-heparin fragments was approximately 2.4 hr. Covalent coupling of the fragments to antithrombin III increased this half-life about 3.5 fold (t1/2 ≃ 7.7 hr), approaching that of free antithrombin III (t1/2 ≃ 11 ± 0.4 hr) and resulting in a 30fold longer life time of factor Xa inhibitory activity in plasma as compared to that of free intact heparin (t1/2 ≃ 0.25 ± 0.04 hr).

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Effects of Acute Hypobaric Hypoxia Exposure on Neurocognitive Performance of Pre-hospital Emergency Service Providers

Case Medical Research ◽

10.31525/ct1-nct04138446 ◽

2019 ◽

Author(s):

Keyword(s):

Hypobaric Hypoxia ◽

Emergency Service ◽

Service Providers ◽

Neurocognitive Performance ◽

Hospital Emergency ◽

Acute Hypobaric Hypoxia ◽

Hypoxia Exposure ◽

Hospital Emergency Service

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Simultaneous optimization of activity and stability of xylose reductase from D. nepalensis NCYC 3413 using statistical experimental design

Protein and Peptide Letters ◽

10.2174/0929866527666201103145246 ◽

2020 ◽

Vol 27 ◽

Author(s):

Shwethashree Malla ◽

Sathyanarayana N. Gummadi

Keyword(s):

Half Life ◽

Specific Activity ◽

Enzyme Stability ◽

Reductase Activity ◽

Xylose Reductase ◽

Life Time ◽

Economic Feasibility ◽

Simultaneous Optimization ◽

Physical Parameters ◽

Statistical Experimental Design

Background: Physical parameters like pH and temperature play a major role in the design of an industrial enzymatic process. Enzyme stability and activity are greatly influenced by these parameters; hence optimization and control of these parameters becomes a key point in determining the economic feasibility of the process. Objective: This study was taken up with the objective to optimize physical parameters for maximum stability and activity of xylose reductase from D. nepalensis NCYC 3413 through separate and simultaneous optimization studies and comparison thereof. Method: Effects of pH and temperature on the activity and stability of xylose reductase from Debaryomyces nepalensis NCYC 3413 were investigated by enzyme assays and independent variables were optimised using surface response methodology. Enzyme activity and stability were optimised separately and concurrently to decipher the appropriate conditions. Results: Optimized conditions of pH and temperature for xylose reductase activity were determined to be 7.1 and 27 ℃ respectively, with predicted responses of specific activity (72.3 U/mg) and half-life time (566 min). The experimental values (specific activity 50.2 U/mg, half-life time 818 min) were on par with predicted values indicating the significance of the model. Conclusion: Simultaneous optimization of xylose reductase activity and stability using statistical methods is effective as compared to optimisation of the parameters separately.

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Radical Intermediates in Photochemical and Redox Initiated Decomposition of Thioazo Compounds(an EPR and Cyclovoltammetric Study)

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19970855 ◽

1997 ◽

Vol 62 (6) ◽

pp. 855-865 ◽

Cited By ~ 3

Author(s):

Katarína Erentová ◽

Vladimír Adamčík ◽

Andrej Staško ◽

Oskar Nuyken ◽

Arming Lang ◽

...

Keyword(s):

Decomposition Rate ◽

Half Life ◽

Spin Trap ◽

Solvent Molecule ◽

Life Time ◽

Radical Intermediates ◽

Reactive Radicals ◽

Induced Decomposition

The cathodically and photochemically induced decomposition of thioazo compounds XC6H4-N2-S-C6H4CH3 and their polymers with X = NO2, COOH, and SO3H were investigated. The formation of carbon-centered XC6H4. and sulfur-centered .S-C6H4Y radicals was confirmed using spin-trap technique. These reactive radicals either abstract hydrogen from CH3CN solvent molecule forming .CH2CN radical or they recombine to cage products XC6H4-S-C6H4CH3 eliminating N2. The decomposition rate of the investigated thioazo compounds is characterized by a formal half-life time of 5 to 10 s.

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