Determination of kinetic parameters for sulfur processing potentials: Verification of the constant specific activity approach

1991 ◽  
Vol 23 (10) ◽  
pp. 1003-1004 ◽  
Author(s):  
A.R. Autry ◽  
J.W. Fitzgerald
Keyword(s):  
Kinetic Parameters ◽  
Specific Activity ◽  
Constant Specific Activity

DEFINITIVE IDENTIFICATION OF MICROQUANTITIES OF RADIOACTIVE STEROIDS BY RECRYSTALLIZATION TO CONSTANT SPECIFIC ACTIVITY

1965 ◽  
Vol 49 (2_Suppl) ◽  
pp. S7-S77 ◽  
Author(s):  
Leonard R. Axelrod ◽  
Charles Matthijssen ◽  
Joseph W. Goldzieher ◽  
Jean E. Pulliam
Keyword(s):  
Liquid Scintillation ◽  
Specific Activity ◽  
Inorganic Materials ◽  
Dual Isotope ◽  
Advantages And Disadvantages ◽  
Yield Values ◽  
Solvent Systems ◽  
Identification Techniques ◽  
Constant Specific Activity

ABSTRACT Studies of steroid metabolism using isotopically-labeled compounds at physiological levels present unique problems in the identification of the metabolites and in the demonstration of their radiochemical purity. The submicrogram quantities of material available preclude the use of classical identification techniques. The character of the evidence obtained, the advantages and disadvantages of chromatographic and countercurrent distribution methods are discussed. Crystallization to constant specific activity is a recognized method for demonstrating that a substance is not radiochemically impure. Its parameters have never been accurately defined. Its true power is achieved only when it is preceded by extensive purification of the material to be characterized. In this way, the unknown material is first categorized by its migration rate in various solvent systems, and then by its crystalline identity with the carrier compound. The likelihood of two dissimilar steroids being both isopolar and isomorphic is held to be remote. Liquid scintillation spectrometry and gravimetry are the techniques used for the determination of constant specific activity. This method for measurement of radioactivity is extremely flexible, sensitive, and lends itself to dual-isotope experiments. Gravimetry under standardized conditions is suitably precise and much more generally applicable than spectroscopic quantitation. The parameters of the technique of rapid, forced microcrystallization are analyzed. In particular, the problem of contamination of crystals is analyzed in detail, and it is pointed out that classical concepts of purification by crystallization, developed chiefly in connection with ionic inorganic materials, must be modified when applied to nonionic steroid compounds. A mathematical analysis of the errors inherent in this technique indicates that 3 successive crystallizations of a pure radioactive compound should yield values for the specific activity which are within ± 5 % of the average of the 3 values.

THE CONVERSION OF PREGNENOLONE TO PROGESTERONE AND 16α-HYDROXYDEHYDROEPIANDROSTERONE IN VITRO BY ADRENAL TISSUE FROM A NEWBORN ANENCEPHALIC INFANT

1968 ◽  
Vol 40 (1) ◽  
pp. 29-35 ◽  
Author(s):  
M. M. SHAHWAN ◽  
R. E. OAKEY ◽  
S. R. STITCH
Keyword(s):  
Specific Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Enzymatic Conversion ◽  
Partition Chromatography ◽  
Adrenal Tissue ◽  
Enzyme Systems ◽  
Constant Specific Activity

SUMMARY Adrenal tissue, largely composed of the definitive zone, from a newborn anencephalic infant, contained the following enzyme systems: (1) a Δ5-3β-hydroxysteroid dehydrogenase for pregnenolone, demonstrated by the conversion of [14C]pregnenolone to [14C]progesterone; (2) a C(17)-C(20) desmolase, and (3) a steroid 16α-hydroxylase, demonstrated by the conversion of [14C]pregnenolone to [14C]3β, 16α-dihydroxyandrost-5-en-17-one. The metabolites could not be separated from carrier steroids during sequential partition chromatography. [14C]Progesterone was identified by recrystallization to constant specific activity. [14C]3β, 16α-Dihydroxyandrost-5-en-17-one was identified by enzymatic conversion to [14C]16α-hydroxyoestrone followed by reduction to oestriol and determination of the specific activity of the oestriol after partition chromatography. It is suggested that these enzymes may play some part in the production of cortisol by the newborn anencephalic infant, and in the provision of precursors for placental oestriol production.

CONVERSION OF ANDROGENS INTO OESTROGENS BY HYDATIDIFORM MOLES IN VITRO

1970 ◽  
Vol 64 (1) ◽  
pp. 17-37 ◽  
Author(s):  
Hans L. Houtzager ◽  
Hubertus A. van Leusden ◽  
Maria Siemerink
Keyword(s):  
Specific Activity ◽  
Hydatidiform Mole ◽  
No Conversion ◽  
Direct Pathway ◽  
Endogenous Production ◽  
Hydatidiform Moles ◽  
Constant Specific Activity

ABSTRACT [1,2-3H] and [7α-3H] testosterone* and [4-14C] androstenedione incubated with hydatidiform mole tissue are converted into oestrone and oestradiol. No conversion into oestriol was observed. The radiometabolites were purified using TLC in different systems and crystallization to a constant specific activity and/or 14C/3H ratio. Appropriate corrections were made for endogenous production of steroids during the incubation. From time-experiments with [4-14C] androstenedione and [7α-3H] or [1,2-3H] testosterone it appears, that androstenedione is a more effective precursor than testosterone for oestrone and oestradiol. Equilibrium oestrone ⇋ oestradiol is established more rapidly than androstenedione ⇋ testosterone. Conversion of androstenedione into oestrone is more effective than conversion of testosterone into androstenedione. Data are reported in agreement with the hypothesis of a direct pathway from testosterone to oestradiol in the shorter periods of incubation. Determination of the endogenous pools of oestrone, oestradiol, testosterone and androstenedione synthesized during the incubations indicates that oestrone is the most important steroid produced in vitro.

An Enzyme Linked Immunosorbent Assay for Determination of Tissue Plasminogen Activator Applied to Patients with Thromboembolic Disease

1983 ◽  
Vol 50 (03) ◽  
pp. 740-744 ◽  
Author(s):  
Nils Bergsdorf ◽  
Torbjörn Nilsson ◽  
Per Wallén
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Specific Activity ◽  
Thromboembolic Disease ◽  
Tissue Type ◽  
Enzyme Linked Immunosorbent Assay ◽  
Type Plasminogen Activator ◽  
Tissue Plasminogen ◽  
Normal Human

SummaryUtilizing the immunoglobulin fraction from a goat antiserum against human uterine tissue plasminogen activator, an enzyme- linked immunoassay for tissue-type plasminogen activator in human plasma has been developed. With the new method, the concentration of t-PA in normal human acidified plasma is found to be 4.0 ± 1.8 (SD) ng/ml. It increases to 12 ng/ml after a tomiquet test, and to 14 ng/ml after strenous physical exercise. In a group of patients with idiopathic thromboembolic disease, the resting t-PA concentration was 5 ng/ml and the post-occlusion value 16 ng/ml. Furthermore, the patients also exhibited a normal post-occlusion rise in the concentration of plasmin-α2-antiplasmin complex. However, in 37% of the post-occlusion patient plasmas, virtually no increase in t-PA could be detected by a specific activity assay. The results indicate that the reason for a defective post-occlusion fibrinolytic activity in a majority of cases may be the presence of increased concentrations of a fast-acting specific t-PA inhibitor.

THE LESS-POLAR METABOLITES PRODUCED BY INCUBATION OF TESTOSTERONE-4-14C WITH RAT AND BOVINE BRAIN

1969 ◽  
Vol 61 (4) ◽  
pp. 641-648 ◽  
Author(s):  
Leon J. Sholiton ◽  
Emile E. Werk
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Paper Chromatography ◽  
Specific Activity ◽  
Bovine Brain ◽  
Polar Fraction ◽  
End Products ◽  
Polar Metabolites ◽  
Layer Chromatography ◽  
Constant Specific Activity

ABSTRACT Rat and bovine brain have been incubated with testosterone-4-14C under standard conditions. With use of paper chromatography, the extracted metabolites were noted to fall into less-polar, iso-polar, and more polar fractions. The components of the less-polar fraction were separated by acetylation and thin-layer chromatography and the major end-products identified by recrystallization to constant specific activity or constant 3H/14C ratios. Androst-4-enedione and 5α-dihydrotestosterone were formed consistently under the conditions utilized. Trace amounts of other less-polar metabolites were noted occasionally.

MEASUREMENT OF STEROID BINDING PROTEINS

1970 ◽  
Vol 65 (1_Suppl) ◽  
pp. S104-S121 ◽  
Author(s):  
E. E. Baulieu ◽  
J. P. Raynaud ◽  
E. Milgrom
Keyword(s):  
Kinetic Parameters ◽  
Binding Proteins ◽  
Binding Specificity ◽  
Binding Parameters ◽  
Target Organs ◽  
Biological Mixtures ◽  
Steroid Binding Proteins ◽  
Steroid Binding ◽  
Steroid Binding Protein

ABSTRACT A brief review of the characteristics of steroid binding proteins found in the plasma and in some target organs is presented, followed by some general remarks on binding »specificity« and binding parameters. Useful techniques for measuring binding parameters at equilibrium are reported, both those which keep the equilibrium intact and those which implicate its disruption. A concept is developed according to which the determination of a specific steroid binding protein is based on the »differential dissociation« of the several steroid binding complexes present in most biological mixtures. Methods which allow determination of the kinetic parameters of the binding systems are also presented. Various representations of the binding and therefore different modes of graphic representation and calculation are discussed, including the recent »proportion graph« method.

Determination of Specific Activity of Cholera Chemical Vaccine Components using Cell Culture

2020 ◽  
Vol 36 (3) ◽  
pp. 82-89
Author(s):  
O.V. Gromova ◽  
O.S. Durakova ◽  
S.V. Generalov ◽  
L.F. Livanova ◽  
O.A. Volokh
Keyword(s):  
Cell Culture ◽  
Vibrio Cholerae ◽  
Production Control ◽  
Specific Activity ◽  
Methodological Approach ◽  
Toxin Production ◽  
Submerged Cultivation ◽  
Vaccine Production ◽  
Antigenic Activity

Том 36(2020) №3 стр. 82-89; DOI 10.21519/0234-2758-2020-36-3-82-89А.В. Гаева1*, О.В. Громова1, О.С. Дуракова1, С.В. Генералов1, Л.Ф. Ливанова1, О.А. Волох1 Определение специфической активности компонентов холерной химической вакцины с использованием культуры клеток 1ФКУЗ «Российский научно-исследовательский противочумный институт «Микроб»» Федеральной службы по надзору в сфере защиты прав потребителей и благополучия человека, Саратов 410005 *[email protected] Поступила - 2019-11-26; После доработки - 2020-03-16; Принята к публикации - 2020-05-15 Список литературы Описаны методы определения динамики продукции токсинов штаммом Vibrio cholerae 569B при глубинном культивировании в биореакторе и антигенной активности специфической фракции холерогена-анатоксина по анатоксинсвязыванию с использованием клеточных культур. Показана высокая степень соответствия результатов, полученных методами, применяемыми для контроля этапов производства холерной химической вакцины и рассмотренными в данной работе. Отмечено, что применение клеточной линии СНО-К1 наиболее перспективно для замены биомоделей на промежуточных этапах контроля активных компонентов холерной химической вакцины. Разработанный методический подход впервые предлагается использовать на этапах производства холерной бивалентной химической вакцины. культура клеток, Vibrio cholerae, холерная химическая вакцина, контроль производства, холера. Vol 36(2020) N 3 p. 82-89; DOI 10.21519/0234-2758-2020-36-3-82-89A.V. Gaeva1*, O.V. Gromova1, O.S. Durakova1, S.V. Generalov1, L.F. Livanova1, O.A. Volokh1 Determination of Specific Activity of Cholera Chemical Vaccine Components using Cell Culture 1Russian Research Anti-Plague Institute «Microbe» of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing, Saratov, 410005 *[email protected] Received - 26.11.2019; Accepted - 15.05.2020 References The methods has been described to determine the dynamics of toxin production by the Vibrio cholerae 569B strain during submerged cultivation in bioreactor and of the antigenic activity of specific choleragen anatoxin fraction by anatoxin binding levels using cell cultures. High degree of consistency was observed between the results obtained via the method under consideration and those obtained via control methods at different stages of cholera chemical vaccine production. It was shown that the CHO-K1 cell line is the most promising substitute for biomodels at the intermediate stages of control of active cholera chemical vaccine components. The developed methodological approach was first proposed for use at the stages of cholera chemical bivalent vaccine manufacturing. cell culture, Vibrio cholerae, cholera chemical vaccine, production control, cholera.

The Natural Radioactivity in Food: A Comparison Between Different Feeding Regimes

2019 ◽  
Vol 15 (5) ◽  
pp. 493-499 ◽  
Author(s):  
Francesco Caridi ◽  
Santina Marguccio ◽  
Alberto Belvedere ◽  
Maurizio D`Agostino ◽  
Giovanna Belmusto
Keyword(s):  
Vegetable Oils ◽  
Natural Radioactivity ◽  
Specific Activity ◽  
Mean Value ◽  
Vegetable Food ◽  
Fish Samples ◽  
Feeding Regimes ◽  
Italian Origin ◽  
Dose Levels

Background: In this article a comprehensive study was carried out for the determination of natural radioactivity in animal and vegetable food (meat, fish, milk and derivates, legumes, cereals and derivates, fruit, hortalizas, vegetables, vegetable oils) typical of different feeding regimes, for the age category higher than 17 years. Methods: A total of eighty-five samples of Italian origin, coming from large retailers during the years 2014, 2015 and 2016, were analyzed through HPGe gamma spectrometry. Results: The specific activity of 40K was investigated and its mean value was found to be: (106.3 ± 6.9) Bq/kg for bovine, swine and sheep meat; (116.5 ± 9.7) Bq/kg for fish; (52.9 ± 3.1) Bq/kg for milk and derivates; (271.9 ± 16.7) Bq/kg for legumes; (67.2 ± 4.7) Bq/kg for cereals and derivates; (52.7 ± 4.4) Bq/kg for fruit; (72.9 ± 5.6) Bq/kg for hortalizas; (83.9 ± 6.5) Bq/kg for vegetables; lower than the minimum detectable activity for vegetable oils. For animal food the highest mean 40K activity concentration was found in fish samples; for vegetable food the highest one was detected in legumes. Conclusion: The evaluation of dose levels due to the food ingestion typical of Mediterranean, Vegetarian and Vegan diets was performed. The annual effective dose was found to be 0.16 mSv/y, 0.41 mSv/y and 0.54 mSv/y, respectively.

Regeneration Mechanism Studied by Potential-Time Response to Sinusoidal Current-Time Function

1997 ◽  
Vol 62 (10) ◽  
pp. 1511-1526
Author(s):  
María-Luisa Alcaraz ◽  
Ángela Molina
Keyword(s):  
Kinetic Parameters ◽  
Rate Constant ◽  
Theoretical Study ◽  
Time Function ◽  
Time Response ◽  
Current Time ◽  
Regeneration Mechanism ◽  
Sinusoidal Current ◽  
Regeneration Processes

A theoretical study of the potential-time response to sinusoidal current applied to static and dynamic electrodes for regeneration processes is presented. Methods for determination of the regeneration fraction, rate constant of the chemical reaction and heterogeneous kinetic parameters are proposed.

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