Effect of thiol oxidation and thiol export from erythrocytes on determination of redox status of homocysteine and other thiols in plasma from healthy subjects and patients with cerebral infarction

1995 ◽  
Vol 41 (3) ◽  
pp. 361-366 ◽  
Author(s):  
A Andersson ◽  
A Lindgren ◽  
B Hultberg
Keyword(s):  
Cerebral Infarction ◽  
Healthy Subjects ◽  
Redox Status ◽  
Reduced Form ◽  
Temperature Dependent ◽  
First Order ◽  
First Order Kinetics ◽  
Before And After ◽  
Reduced Forms

Abstract Changes in concentration of reduced and oxidized low-M(r) thiols were measured in blood and plasma before and after the separation of blood cells. If centrifugation of blood was postponed, the reduced form of homocysteine in plasma increased with time at 22 degrees C; in contrast, the concentrations of other reduced thiols (cysteine, glutathione, and cysteinylglycine) decreased. In plasma the reduced forms of all thiols disappeared at a rate that followed first-order kinetics. The rates of disappearance ("half-lives") were temperature-dependent; they were about the same for glutathione and homocysteine (11.7 and 14.3 min, respectively, at 22 degrees C) and somewhat higher for cysteinylglycine and cysteine. After establishing proper sampling conditions for reduced thiols, we measured this thiol fraction as well as free (non-protein-bound) and total thiols in 10 reference subjects and 19 patients with cerebral infarction. Mild but significant hyperhomocysteinemia involving total and free homocysteine (but not reduced homocysteine) was found in the patients.

Type 2 diabetes mellitus in patients with acute ischemiс stroke is associated with a decrease in plasma glutathione levels

2020 ◽  
Vol 25 (5) ◽  
pp. 29-35
Author(s):  
M. Yu. Maksimova ◽  
A. V. Ivanov ◽  
K. A. Nikiforova ◽  
F. R. Ochtova ◽  
E. T. Suanova ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Redox Status ◽  
Reduced Form ◽  
Glutathione Level ◽  
Total Glutathione ◽  
Diabetes Mellitus Group ◽  
Reduced Forms

Ischemic stroke (IS) and type 2 diabetes mellitus are factors that affect the homeostasis of low-molecularweight aminothiols (cysteine, homocysteine, glutathione etc.). It has already been shown that IS in the acute period led to a decrease a level of reduced forms of aminothiols, but it is not clear whether type 2 diabetes mellitus has a noticeable effect there. Objective: to reveal the features of homeostasis of aminothiols in patients with type 2 diabetes mellitus in acute IS. Material and methods. The study involved 76 patients with primary middle cerebral artery IS in the first 10–24 hours after development of neurological symptoms. Group 1 included 15 patients with IS and type 2 diabetes mellitus, group 2 — 61 patients with IS and stress hyperglycemia. Their total plasma levels of cysteine, homocysteine, and glutathione, their reduced forms, and redox status were determined at admission (in the first 24 hours after IS). Results. There was a decrease in the level of total glutathione level (1.27 vs. 1.65 μM, p = 0.021), as well as its reduced form (0.03 vs. 0.04 μM, p = 0.007) in patients with IS and type 2 diabetes mellitus. Patients with type 2 diabetes mellitus who had a low redox status of homocysteine (0.65–1.2%) and glutathione (0.7–2.0%) were also characterized by a decrease in total glutathione level (p = 0.02; p = 0.03). Conclusion. Thus, type 2 diabetes mellitus is associated with a decrease in the level of total glutathione in acute IS. Probably, type 2 diabetes mellitus is characterized by a particular relationship between the metabolism of homocysteine, glutathione and glucose. Therefore, the search for homocysteine-dependent approaches to correct glutathione metabolism in type 2 diabetes mellitus may be of interest as an adjuvant therapy for IS.

scholarly journals Simultaneous Determination and Stability Studies on Diminazene Diaceturate and Phenazone Using Developed Derivative Spectrophotometric Method

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Ruaa Mohamed Akode ◽  
Shaza Wagiealla Shantier ◽  
Elrasheed Ahmed Gadkariem ◽  
Magdi Awadalla Mohamed
Keyword(s):  
Simultaneous Determination ◽  
Correlation Coefficients ◽  
Degradation Process ◽  
Stability Studies ◽  
Temperature Dependent ◽  
First Order Kinetics ◽  
First Derivative Spectrophotometry ◽  
Aqueous Mixture ◽  
Photo Stability

This work presents UV first derivative spectrophotometry as a precise, accurate, and feasible method for simultaneous determination of diminazene diaceturate and phenazone in bulk and dosage forms. The absorbance values of diminazene diaceturate and phenazone aqueous mixture were obtained at 398 nm and 273 nm, respectively. The developed method was proved to be linear over the concentration ranges (2–10) μg/mL and (2.496–12.48) μg/mL for diminazene diaceturate and phenazone, respectively, with good correlation coefficients (not less than 0.997). The detection and quantitation limits were found to be (LOD = 0.63 and 0.48 μg/mL; LOQ = 1.92 and 1.47 μg/mL, resp.). The developed method was employed for stability studies of both drugs under different stress conditions. Diminazene diaceturate was prone to degrade at acidic pH via first-order kinetics. The degradation process was found to be temperature dependent with an activation energy of 7.48 kcal/mole. Photo-stability was also investigated for this drug.

Modified ferron assay for speciation characterization of hydrolyzed Al(III): a precise k value based judgment

2009 ◽  
Vol 59 (4) ◽  
pp. 823-832 ◽  
Author(s):  
Ye Changqing ◽  
Wang Dongsheng ◽  
Wu Xiaohong ◽  
Qu Jiuhui ◽  
John Gregory
Keyword(s):  
Kinetic Constant ◽  
Nonlinear Least Squares ◽  
Precise Determination ◽  
K Value ◽  
First Order ◽  
First Order Kinetics ◽  
Parallel Reactions

The speciation of Al-OH complexes in terms of Ala, Alb and Alc could be achieved by traditional ferron assay and Alb is generally considered as Al13, however, the inherent correlation between them remains an enigma. This paper presents a modified ferron assay to get precise determination of Al13 using nonlinear least squares analysis, and to clarify the correlation between Alb and Al13. Two parallel reactions conforming to pseudo-first-order kinetics can simulate the complicate reactions between polynuclear complexes and ferron successfully. Four types of experimental kinetic constant (k value) of Al-OH complexes can be observed by this method when investigating three typical aluminium solutions. Comparing with the results of 27Al NMR, the species with moderate kinetics around 0.001 s−1 can be confirmed to resemble to Al13 polycation. The other types of kinetics are also well-regulated in partially neutralized aluminium solutions with various OH/Al ratios (b values) in the range 0 ∼ 2.5. It would provide potential means to trace the in-situ formation of Al13 in dilute solutions such as coagulation with Al-based coagulants

Deep breath reversal and exponential return of methacholine-induced obstruction in asthmatic and nonasthmatic subjects

2004 ◽  
Vol 96 (1) ◽  
pp. 137-142 ◽  
Author(s):  
Andrew C. Jackson ◽  
Margaret M. Murphy ◽  
John Rassulo ◽  
Bartolome R. Celli ◽  
Roland H. Ingram
Keyword(s):  
Healthy Subjects ◽  
Time Course ◽  
Rapid Decrease ◽  
Airway Wall ◽  
Methacholine Challenge ◽  
Order Process ◽  
Deep Breath ◽  
First Order ◽  
Before And After ◽  
Complete Reversal

A deep breath (DB) during induced obstruction results in a transient reversal with a return to pre-DB levels in both asthmatic and nonasthmatic subjects. The time course of this transient recovery has been reported to be exponential by one group but linear by another group. In the present study, we estimated airway resistance (Raw) from measurements of respiratory system transfer impedance before and after a DB. Nine healthy subjects and nine asthmatic subjects were studied at their maximum response during a methacholine challenge. In all subjects, the DB resulted in a rapid decrease in Raw, which then returned to pre-DB levels. This recovery was well fit with a monoexponential function in both groups, and the time constant was significantly smaller in the asthmatic than the nonasthmatic subjects (11.6 ± 5.0 and 35.1 ± 15.9 s, respectively). Obstruction was completely reversed in the nonasthmatic subjects (pre- and postchallenge mean Raw immediately after the DB were 2.03 ± 0.66 and 2.06 ± 0.68 cmH2O·l-1·s, respectively), whereas in the asthmatic subjects complete reversal did not occur (2.29 ± 0.78 and 4.84 ± 2.64 cmH2O·l-1·s, respectively). Raw after the DB returned to postchallenge, pre-DB values in the nonasthmatic subjects (3.78 ± 1.56 and 3.97 ± 1.63 cmH2O·l-1·s, respectively), whereas in the asthmatic subjects it was higher but not significantly so (9.19 ± 4.95 and 7.14 ± 3.56 cmH2O·l-1·s, respectively). The monoexponential recovery suggests a first-order process such as airway wall-parenchymal tissue interdependence or renewed constriction of airway smooth muscle.

scholarly journals Mineralization of sulfonamides from wastewater using ozone-based systems

2021 ◽  
Author(s):  
T. H. Ho ◽  
C. H. Wu ◽  
T. Y. Han ◽  
W. J. Syu
Keyword(s):  
Steric Hindrance ◽  
Radical Addition ◽  
The Novel ◽  
Mineralization Rate ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Uv Ozone ◽  
Heterocyclic Group

Abstract Ozone, UV/ozone, ozone/persulfate (PS) and UV/ozone/PS systems were used to mineralize sulfonamides. Sulfadiazine (SDZ), sulfamerazine (SMR) and sulfamethazine (SMZ) were the target compounds. The novel contribution of this study is its determination of the effects of PS addition, sulfonamide structure, pH and salinity on sulfonamide mineralization in ozone-based systems. The mineralization rate of sulfonamides satisfied pseudo-first-order kinetics. The SMZ mineralization rate constant in ozone, UV/ozone, ozone/PS and UV/ozone/PS systems at pH 5 were 0.0058; 0.0101; 0.0069 and 0.0802 min−1, respectively, and those at pH 7 were 0.0075; 0.0116; 0.0083 and 0.0873 min−1, respectively. The increase in the number of methyl-substituents in the heterocyclic group of SMZ and the corresponding increase in the steric hindrance of radical addition, reduced mineralization rates below those of SMR and SDZ. The addition of PS promoted sulfonamide mineralization in the ozone-based systems; conversely, salinity inhibited sulfonamide mineralization.

Salicylate Kinetics In The Rat: Relationship To Antithrombotic Activity

1981 ◽  
Author(s):  
R B Philp ◽  
I Francey
Keyword(s):  
Carotid Arteries ◽  
Post Injection ◽  
Antithrombotic Effect ◽  
Protective Level ◽  
Antithrombotic Activity ◽  
First Order ◽  
First Order Kinetics ◽  
Salicylate Level ◽  
Before And After ◽  
Prostacyclin Synthesis

Recently we reported that acetylsalicylic acid (ASA) 100 mg/kg i.v. had no antithrombotic effect in a rat model of arterial thrombosis whereas 200 mg/kg i.v. had significant antithrombotic activity. The present study investigates salicylate kinetics at the non-protective level. Carotid arteries of urethane-anesthetized rats were injured electrically (1 mA, DC, for 1 min) and thrombogenesis measured by recording downstream temperature. Right and left side injuries were compared before and after ASA, 100 mg/kg i.v. Blood samples were collected at various times post injection and serum assayed for salicylate content by Trinder’s method. All salicylate levels are reported as mg/dL ± SEM. Control injuries produced a temperature fall of 1.4°C ± 0.08 (SEM) and post ASA injuries a fall of 1.8°C ± 0.17 (SEM) (P < .1 > .05). Serum salicylate was 20 mg ± 4.58 1 min post injection and the calculated lh was 40 min with decay following first order kinetics. The intraperitoneal injection of ASA 200 mg/kg produced a serum salicylate level of 8.1 ± 1.55 5 min post injection with a peak of 19 ± 2.03 30 min post injection. Both absorption and elimination followed first order kinetics with Th values of 10 and 44 min respectively. Urine collected 40 min post injection contained 9.4 ± 3.38 free salicylate which increased to about 40 following chemical digestion, indicating the presence of metabolites. The results indicate that serum salicylate levels < 20 do not offer antithrombotic protection in this model and that this level is achieved only briefly following ASA 100 mg/kg i.v. or 200 mg/kg i.p. The brief half-life of ASA in the rat has implications for the interpretation of data concerning the inhibition of prostacyclin synthesis by vessel wall. The wide variation in effective ASA doses reported for various animal models of thrombosis is probably a function of the nature of the model rather than of efficient prostacyclin synthesis.

Macrokinetics and Mechanism of Phenol Solution Degradated by Fe3+/Ce4+ Doped TiO2 Particles

2014 ◽  
Vol 955-959 ◽  
pp. 411-414
Author(s):  
Yu Fei Wang ◽  
Long Yan ◽  
Jian Li
Keyword(s):  
Degradation Process ◽  
Isobutyric Acid ◽  
Phenol Solution ◽  
First Order ◽  
Degradation Reactions ◽  
First Order Kinetics ◽  
Before And After ◽  
Mechanism Of Degradation ◽  
Butanedioic Acid ◽  
Dynamic Cycle

Fe3+/Ce4+doped TiO2particles was prepared and used for degradation of phenol solution, the macrokinetics and mechanism of degradation process was proposed by GC-MS, and Fe3+/Ce4+-doped TiO2particles before and after treated phenol was also compared by TEM. The experimental results showed that COD degradation reactions in static and dynamic cycle process are in accordance with first-order kinetics from the macro effects, phenol can be oxidized to intermediates, such as isobutyric acid, malonic acid, para-benzoquinone, butenic acid, ethanedioic acid, maleic acid, butanedioic acid, o-dihydroxybenzene, paradioxybenzene and dioxybenzene, indicating that Fe3+/Ce4+-doped TiO2particles are beneficial to some oxidation formation. Moreover, the shapes of Fe3+/Ce4+-doped TiO2particles after treated phenol displays aggregated.

scholarly journals ESTUDO DE ESTABILIDADE DO FOSFATO DISSÓDICO DE PREDNISOLONA EM CONDIÇÕES DE ESTRESSE OXIDATIVO E TÉRMICO, EM FORMULAÇÃO ORAL

2018 ◽  
Vol 35 (4) ◽  
pp. 09
Author(s):  
Cleber Antonio Lindino ◽  
Marcia Lina Mitsui ◽  
Rodolfo Ortiguara ◽  
Daiane Felin ◽  
Mauricio Ferreira Da Rosa ◽  
...  
Keyword(s):  
High Performance ◽  
Dosage Form ◽  
Degradation Products ◽  
Degradation Process ◽  
Oral Solution ◽  
Form Solution ◽  
Oral Dosage ◽  
First Order ◽  
First Order Kinetics

This work was to investigate the process of degradation of the drug Prednisolone Sodium Phosphate (FSP) in oral solution dosage form through the degradation experiments, evaluating the parameters in accordance with Resolution 899/2003 ANVISA and the degradation process of the drug. The method by high performance liquid chromatography (HPLC) developed for the determination of the drug was validated to demonstrate its applicability as an indicator of stability, ensuring reliability. After the method be validated to study the degradation of the drug, it was shown that drastic conditions of oxidative stress (H O 30%) and 2 2 temperature 60°C, the degradation of the drug is dependent on its concentration (first order kinetics). The results were  satisfactory, showing that this method is suitable to investigate the formation of degradation products in oral dosage form solution

scholarly journals Determination of Ozone or Hypochlorite in Waters Based on Digital Images Analysis Using Same Reagent

2021 ◽  
Author(s):  
Lorrayne Zampier ◽  
André Fernando de Oliveira ◽  
Fernanda Heleno ◽  
Maria Eliana de Queiroz ◽  
Antônio Augusto Neves ◽  
...  
Keyword(s):  
Digital Image Analysis ◽  
Digital Images ◽  
First Order ◽  
Figures Of Merit ◽  
Malachite Green Dye ◽  
First Order Kinetics ◽  
The Subject ◽  
Different Response ◽  
Analytical Resolution

Ozone and hypochlorite are used for the disinfection of water and is essential to monitor these. In this paper, methods based on digital images were developed to determine these analytes in waters using the malachite green dye. The oxidation of the reagent with ozone was very fast and with hypochlorite occurred in 10 min in pseudo-first-order kinetics. New software called ICCA was developed for the capture and processing of red, green and blue (RGB) data, which is planned for digital image analysis. In addition, the recently proposed parameters analytical resolution and N9 were used to define some study conditions. An evaluation of different response functions and white correction of the webcam were done, having thrown some light on the subject to this theme. Their optimization showed a linear range from 0.6 mg L-1 to 5.0/6.0 mg L-1 (O3/Cl, respectively). The figures of merit were similar for both. The methods were validated and the recoveries achieved were between 85.0 and 96.0% (ozone) and 101.0 and 119.0% (hypochlorite).

scholarly journals A KINETIC ANALYSIS OF THE RENIN-ANGIOTONIN PRESSOR SYSTEM AND THE STANDARDIZATION OF THE ENZYMES RENIN AND ANGIOTONASE

1943 ◽  
Vol 78 (5) ◽  
pp. 367-386 ◽  
Author(s):  
Albert A. Plentl ◽  
Irvine H. Page
Keyword(s):  
Pressor Response ◽  
Accurate Method ◽  
Enzyme Concentration ◽  
Renin Substrate ◽  
First Order ◽  
First Order Kinetics ◽  
Consecutive Reactions ◽  
Slow Decline ◽  
Reaction Constant

The physicochemical background of the renal vasporessor system (renin-renin-substrate, angiotinin, angiotonase) is given. The formation and destruction of angiotonin is shown to consist of two consecutive reactions, both of which follow the laws of first order kinetics. Each reaction was studied separately and its reaction constant found to be proportional to the enzyme concentration. Hence these constants should be used to express the activity of the enzymes, renin and angiotonase. The over-all reaction of a mixture of renin and angiotonase such as occurs in kidney extracts with the α-globulin fraction of serum, viz., rapid increase followed by a slow decline in angiotonin concentration, was found experimentally to correspond closely to the theoretical values calculated for such a reaction. The curve obtained also satisfyingly explains the characteristic pressor response to the intravenous injection of renin. An accurate method for the determination of renin in the presence of angiotonase is presented.

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