scholarly journals γ-butyrobetaine in tissues and serum of fed and starved rats determined by an enzymic radioisotopic procedure

1984 ◽  
Vol 220 (3) ◽  
pp. 701-706 ◽  
Author(s):  
H Noël ◽  
R Parvin ◽  
S V Pande
Keyword(s):  
High Activity ◽  
Rat Liver ◽  
Skeletal Muscles ◽  
Adult Rats ◽  
Male Adult ◽  
Low Concentration ◽  
High Affinity ◽  
The Mean

A method for the determination of picomole quantities of gamma-butyrobetaine and its application for the determination of gamma-butyrobetaine distribution in tissues are described. The method is based on the quantitative conversion of gamma-butyrobetaine into carnitine by using a 50-60%-satd.-(NH4)2SO4 fraction of rat liver supernatant as the source of gamma-butyrobetaine hydroxylase [4-trimethylaminobutyrate,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating), EC 1.14.11.1]; the carnitine formed is then measured enzymically. The mean gamma-butyrobetaine content, as nmol/g wet wt. of tissue, ranged from a low of 4.6 in livers to a high of 12.3 in hearts of normal fed male adult rats. Starvation for 48 h did not affect the gamma-butyrobetaine concentration in serum, liver and brain, but that in skeletal muscles, kidney and heart was increased. These data are in line with the present views that most tissues are able to produce gamma-butyrobetaine, and show that starvation enhances the synthesis and/or the retention of this compound in many tissues. The observed high affinity of gamma-butyrobetaine hydroxylase for gamma-butyrobetaine (Km 7 microM), the high activity of this enzyme and the low concentration of gamma-butyrobetaine in liver indicate that gamma-butyrobetaine availability is one of the factors that normally limit carnitine synthesis.

scholarly journals Assay of Procarboxypeptidase U, a Novel Determinant of the Fibrinolytic Cascade, in Human Plasma

1999 ◽  
Vol 45 (6) ◽  
pp. 807-813 ◽  
Author(s):  
Katinka A Schatteman ◽  
Filip J Goossens ◽  
Simon S Scharpé ◽  
Hugo M Neels ◽  
Dirk F Hendriks
Keyword(s):  
Human Plasma ◽  
Binding Sites ◽  
Hippuric Acid ◽  
Active Form ◽  
Reference Interval ◽  
Healthy Individuals ◽  
High Affinity ◽  
Lysine Residues ◽  
The Mean

Abstract Background: Procarboxypeptidase U (proCPU) is a novel proenzyme found in human plasma. The active form, carboxypeptidase U (CPU; EC 3.4.17.20), retards the rate of fibrinolysis through its ability to cleave C-terminal lysine residues on fibrin partially degraded by plasmin. This reduces the number of high-affinity plasminogen-binding sites on fibrin. Methods: We developed an assay to determine the proCPU concentration in human plasma. The assay involved quantitative conversion of proCPU to active CPU by thrombin-thrombomodulin, a very efficient activator of proCPU, followed by determination of the enzymatic activity of CPU with the substrate hippuryl-l-arginine, using an HPLC-assisted determination of the released hippuric acid. Using this method, we established a reference interval based on 490 healthy individuals. Results: The mean proCPU concentration, determined after activation of the zymogen in diluted plasma and expressed as CPU activity, was 964 U/L, with a SD of 155 U/L. The population showed a gaussian distribution. However, we noticed important differences related to age and the use of hormone preparations. Conclusions: The sensitivity and precision of the method make it suitable for routine clinical determinations and as a reference procedure.

scholarly journals Substrate specificity of an aflatoxin-metabolizing aldehyde reductase

1995 ◽  
Vol 312 (2) ◽  
pp. 535-541 ◽  
Author(s):  
E M Ellis ◽  
J D Hayes
Keyword(s):  
Substrate Specificity ◽  
High Activity ◽  
Rat Liver ◽  
Aflatoxin B1 ◽  
Succinic Semialdehyde ◽  
Aldehyde Reductase ◽  
Aliphatic Aldehydes ◽  
Alpha Beta ◽  
Low Activity

The enzyme from rat liver that reduces aflatoxin B1-dialdehyde exhibits a unique catalytic specificity distinct from that of other aldo-keto reductases. This enzyme, designated AFAR, displays high activity towards dicarbonyl-containing compounds with ketone groups on adjacent carbon atoms; 9,10-phenanthrenequinone, acenaphthenequinone and camphorquinone were found to be good substrates. Although AFAR can also reduce aromatic and aliphatic aldehydes such as succinic semialdehyde, it is inactive with glucose, galactose and xylose. The enzyme also exhibits low activity towards alpha, beta-unsaturated carbonyl-containing compounds. Determination of the apparent Km reveals that AFAR has highest affinity for 9,10-phenanthrenequinone and succinic semialdehyde, and low affinity for glyoxal and DL-glyceraldehyde.

A modified radioimmunoassay for 1,25-dihydroxycholecalciferol.

1981 ◽  
Vol 27 (3) ◽  
pp. 458-463 ◽  
Author(s):  
T K Gray ◽  
T McAdoo ◽  
D Pool ◽  
G E Lester ◽  
M E Williams ◽  
...  
Keyword(s):  
Radioligand Binding ◽  
Normal Range ◽  
High Affinity ◽  
Organic Extraction ◽  
The Mean ◽  
The Stability ◽  
Mean Concentration ◽  
Chromatographic Isolation ◽  
Normal Adults

Abstract A radioimmunoassay for 1,25-dihydroxycholecalciferol which did not cross react with 1,25-dihydroxyergocalciferol is described. IgG fractions were prepared from the serum of rabbits that had been immunized with 1,25-dihydroxycholecalciferol-3-hemisuccinate coupled to bovine albumin. Radioligand binding by the IgG fractions was time-, temperature-, and pH-dependent. The IgG fractions had a high affinity for 1,25-dihydroxycholecalciferol but cross reacted with 25-hydroxycholecalciferol and 24,25-dihydroxycholecalciferol. Vitamin D2 metabolites did not cross react in the assay when amounts up to 9 ng per tube were tested. The determination of 1,25-dihydroxycholecalciferol in human serum required an organic extraction and chromatographic isolation of the metabolite. Radioligand binding was influenced by the presence and concentration of the proteins in the phosphate buffer. The mean concentration of 1,25-dihydroxycholecalciferol in serum from normal adults was 56 (SEM 5.7) ng/L. 1,25-Dihydroxycholecalciferol was not detectable in serum from a nephrectomized subject and the concentration in serum was lower than normal in hypoparathyroid patients. Ingestion of 1,25-dihydroxycholecalciferol by nephrectomized or hypoparathyroid patients restored the concentration of 1,25-dihydroxycholecalciferol in serum to the normal range. The stability of the IgG fraction, the relatively short incubation interval, and the ability to measure 1,25-dihydroxycholecalciferol without interference from 1,25-dihydroxyergocalciferol are unique aspects of this radioimmunoassay.

Quantitative Determination of 1-131, Cs-137, and Ba-140 in Milk: Collaborative Studies

1982 ◽  
Vol 65 (5) ◽  
pp. 1039-1043
Author(s):  
Frederick G D Shuman ◽  
David G Easterly ◽  
Edmond J Baratta
Keyword(s):  
High Activity ◽  
Gamma Ray ◽  
Collaborative Study ◽  
Official Method ◽  
Collaborative Studies ◽  
Coefficients Of Variation ◽  
The Mean ◽  
Method Bias ◽  
Low Activity

Abstract The official method for Cs-137 in milk by gamma-ray spectroscopy was extended to include 1-131 and Ba- 140. A collaborative study was performed on this method applied to 1-131 concentration in cow's milk; the original collaborative study of the method including all 3 nuclides was reviewed. In the 1-131 study, 1 aliquot of a milk sample containing 82 pCi/L was sent to each of 60 laboratories for triplicate analyses. From 40 responses, the mean of the reported values was 81.6 pCi/L, indicating a method bias below the 5% statistical detectability limit. Within- and between-laboratory coefficients of variation (CVs) were 7 and 8%, respectively. In the 3-nuclide study, 2 samples were sent to 25 laboratories for triplicate analyses; one sample contained 633,305, and 515 pCi/L, respectively, of 1-131, Cs-137, and Ba-140 and the other contained 98,52, and 72 pCi/L. For the high-activity sample, within-laboratory CVs were 4-5% for the 3 nuclides and between-laboratory CVs were 4-7%. For the low-activity sample, the corresponding results were 6-9% and 8-16%. The method bias was statistically significant at 95% confidence only for Cs-137 in the high-activity sample; reported results were 3% below the known concentration. The extended method was adopted official first action.

Regulation of (Ca2+-Mg2+)-ATPase activity by calcitonin binding to rat liver plasma membranes

1985 ◽  
Vol 110 (1) ◽  
pp. 124-129 ◽  
Author(s):  
Masayoshi Yamaguchi ◽  
Michiyo Ito
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Rat Liver ◽  
Plasma Membranes ◽  
Specific Binding ◽  
Inhibitory Effect ◽  
Maximal Inhibition ◽  
Low Concentration ◽  
High Affinity ◽  
Rat Liver Plasma Membranes

Abstract. The plasma membranes isolated from rat liver bound 125I-labelled ([125I]) synthetic [Asu1,7]eel calcitonin (CT), with increasing concentrations of [125I]CT. This specific binding was completely saturated at a concentration of 0.5 nm CT. A high affinity Ca2+ -stimulated, Mg2+-dependent ATPase [(Ca2+-Mg2+)-ATPase] activity in the plasma membranes was significantly decreased by the presence of a very low concentration of CT (7.4 pm), although the hormone did not affect the activity of the plasma membrane 5′-nucleotidase. The concentration of CT needed for maximal inhibition of (Ca2+-Mg2+)-ATPase in the plasma membranes was less than 0.74 nm. The plasma membranes washed with 10−3% digitonin did not show an inhibitory effect of CT on (Ca2+-Mg2+)-ATPase activity, while the reagent did not have a significant effect on the enzyme. These results suggest that the inhibition of (Ca2+-Mg2+)-ATPase activity maybe part of the mechanism by which CT elevates cytosolic Ca2+ in liver cells.

scholarly journals Nuclear oestrogen receptors in rat liver. Development of assay conditions, characterization and the translocation of oestrogens in vivo

1982 ◽  
Vol 206 (2) ◽  
pp. 279-286 ◽  
Author(s):  
P Tamulevicius ◽  
E R Lax ◽  
A Müller ◽  
H Schriefers
Keyword(s):  
Nuclear Receptors ◽  
Rat Liver ◽  
Binding Sites ◽  
High Affinity ◽  
Deoxyribonuclease I ◽  
Number Of Binding Sites ◽  
Liver Nuclei ◽  
Assay Conditions

A method for the determination of specific oestrogen-receptor binding sites in rat liver nuclei is described. Nuclear receptors showed a high affinity for oestradiol (Kd approximately 3×10(-9)M), a low capacity, and a distinct specificity for substances with known oestrogenic and anti-oestrogenic activity. No sex differences were seen in the concentrations of nuclear receptors from either vehicle- or ethynyloestradiol-pretreated rats. Only a limited number of binding sites could be extracted with 0.4 M-KCl. The remaining sites, which were solubilized by sonication and treatment with deoxyribonuclease I, sedimented at 3-4 S. Of four oestrogens tested (oestradiol, ethynyloestradiol, diethylstilboestrol, tri-p-anisylchloroethylene), ethynyloestradiol was the most effective translocation agent in vivo, nuclear uptake occurring at doses below 1 microgram/rat; changes in salt extractability of nuclear receptors occurred at doses lower than those required to achieve absolute increases in nuclear receptor concentrations.

Detection of Circulating Tissue Factor and Factor VII in a Normal Population

1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Normal Population ◽  
Mean Value ◽  
Factor Vii ◽  
Significant Difference ◽  
Age Dependent ◽  
The Mean ◽  
Highly Correlated ◽  
And Gender

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

Determination of Plasminogen in Clots and Thrombi

1966 ◽  
Vol 16 (01/02) ◽  
pp. 038-050 ◽  
Author(s):  
Ulla Hedner ◽  
Inga Marie Nilsson ◽  
B Robertson
Keyword(s):  
Mean Value ◽  
Main Mechanism ◽  
Clot Lysis ◽  
Post Mortem ◽  
Digestion Time ◽  
Normal Volunteers ◽  
Casein Solution ◽  
The Mean

SummaryThe plasminogen content was determined by a casein method in plasma and serum from 20 normal volunteers. The mean plasminogen content was found to be 10.1 ACU (the arbitrary caseinolytic unit defined in such a way that using a 3% casein solution and a digestion time of 20 min. at 37°C, 10 ACU gave an extinction of 0.300). No difference between serum and plasma regarding the plasminogen content was found.Plasminogen was determined in drained and drained plus washed clots prepared from 2 ml plasma. The highest values found in the drained clots were 0.9 ACU/clot and 0.2 ACU/clot in the drained plus washed clots.Plasminogen was also determined in drained and drained plus washed clots prepared from plasma with added purified plasminogen. The plasminogen was recovered in the washing fluid. According to these tests, then, purified added plasminogen is washed out of the clots.The plasminogen content of 20 thrombi obtained post mortem was also determined. The mean value was found to be 0.7 ACU/cm thrombus. Judging from our results, the “intrinsic clot lysis theory” is not the main mechanism of clot dissolution.

SERUM TRIIODOTHYRONINE DETERMINATION BY SATURATION ANALYSIS

1973 ◽  
Vol 72 (4) ◽  
pp. 714-726 ◽  
Author(s):  
A. Burger ◽  
B. Miller ◽  
C. Sakoloff ◽  
M. B. Vallotton
Keyword(s):  
Ionic Strength ◽  
Limit Of Detection ◽  
Improved Method ◽  
Accuracy Of Measurement ◽  
Tracer Amount ◽  
The Mean ◽  
Physiological Values ◽  
Hyperthyroid Patients ◽  
Solvent Blank

ABSTRACT An improved method for the determination of serum triiodothyronine (T3) has been developed. After addition of a tracer amount of the hormone, T3 was extracted from 1 ml serum under conditions of pH and ionic strength which favoured T3 extraction (89%) over thyroxine (T4) extraction (58%). Chromatography of the extracted material on Sephadex LH-20 separated T3 completely from residual T4. The T3 eluate was dried, then re-dissolved in 0.5 ml NaOH 0.04 n. To 0.2 ml duplicate aliquots, a standard amount of TBG was added for the competitive protein analysis. After one hour incubation at 4°C, separation of bound from free T3 was achieved on small Sephadex G-25 columns. Overall recovery was 67 ± 10.8% and correction for the loss was made. The solvent blank was 37 ± 27 (sd) ng/100 ml. Accuracy of measurement of known quantities of T3 added to serum was 98.4%. The coefficient of variation within the assay was 6.2% and between the assays it was 11.4%. The limit of detection (0.1 ng) corresponded to a concentration of 25 ng/100 ml. T4 added to serum did not interfere with T3 determination until high non-physiological values were reached. The mean ± sd serum T3 in 54 euthyroid subjects was 153 ± 58 ng/100 ml and in 24 hyperthyroid patients it was 428 ±186 ng/100 ml; 4 out of the 24 hyperthyroid values were within 2 sd of the mean euthyroid group. All the values found in the euthyroid group were well above the limit of detection of the method.

Determination of the Probability Distribution of the Mean Sound Level

2010 ◽  
Vol 35 (4) ◽  
pp. 543-550 ◽  
Author(s):  
Wojciech Batko ◽  
Bartosz Przysucha
Keyword(s):  
Probability Distribution ◽  
Probability Distribution Function ◽  
Mean Value ◽  
Sound Level ◽  
Function Form ◽  
Noise Levels ◽  
Logarithmic Mean ◽  
The Mean ◽  
Estimation Of Uncertainty

AbstractAssessment of several noise indicators are determined by the logarithmic mean <img src="/fulltext-image.asp?format=htmlnonpaginated&src=P42524002G141TV8_html\05_paper.gif" alt=""/>, from the sum of independent random resultsL1;L2; : : : ;Lnof the sound level, being under testing. The estimation of uncertainty of such averaging requires knowledge of probability distribution of the function form of their calculations. The developed solution, leading to the recurrent determination of the probability distribution function for the estimation of the mean value of noise levels and its variance, is shown in this paper.

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