scholarly journals Development of an NT-ProBNP Assay Reagent Based on High Specific Activity Alkaline Phosphatase CmAP and an Improved Coupling Method

2020 ◽  
Vol 10 (23) ◽  
pp. 8682
Author(s):  
Hai-Chao Li ◽  
Xin He ◽  
Shan-Peng Qiao ◽  
Zhen-Ni Liu ◽  
Yu-Zhou Gao
Keyword(s):  
Alkaline Phosphatase ◽  
Magnetic Beads ◽  
Specific Activity ◽  
High Specific Activity ◽  
High Sensitivity ◽  
Coupling Method ◽  
Purification Method ◽  
In Vitro Diagnostic ◽  
Diagnostic Reagent

(1) Background: Chemiluminescent enzyme immunoassay (CLEIA) is an efficient analytical method. Alkaline phosphatase (ALP) with high specific activity is the basis for CLEIA to achieve high sensitivity. In this study, a high specific activity Cobetia marina ALP (CmAP) and an improved coupling method were used to develop an N-terminal pro-B-type natriuretic peptide (NT-proBNP) diagnostic reagent. (2) Methods: The purification method of CmAP was improved and the related enzyme activities were assessed. The enzyme and magnetic beads were coupled only to the Fc region of the detection antibody and the capture antibody, respectively, by using a specially improved method. The NT-proBNP in human serum was assessed. (3) Results: The specific activity of the purified CmAP was found to be 13,133 U/mg. No loss in the enzyme activity was observed after its storage at room temperature for 4 months. The sensitivity of the in vitro diagnostic reagents was found to be 0.58 ng/L. (4) Conclusions: CmAP can be applied as a substitute for the commercial ALP. Analytical parameters indicated that the chemiluminescence diagnostic reagent for NT-proBNP is adequately sensitive and reliable for detecting the serum NT-proBNP, which suggests that both the enzyme and coupling method are suitable for the CLEIA.

Effects of Heparin Oligosaccharides with High Affinity for Antithrombin III in Experimental Venous Thrombosis

1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
High Specific Activity ◽  
Factor Xa ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
Very High

SummaryThe in vitro and in vivo characteristics of two oligosaccharide heparin fragments have been compared to those of unfractionated mucosal heparin. A decasaccharide fragment had essentially no activity by APTT or calcium thrombin time assays in vitro, but possessed very high specific activity by anti-Factor Xa assays. When injected into rabbits at doses of up to 80 ¼g/kg, this fragment was relatively ineffective in impairing stasis thrombosis despite producing high blood levels by anti-Xa assays. A 16-18 monosaccharide fragment had even higher specific activity (almost 2000 iu/mg) by chromogenic substrate anti-Xa assay, with minimal activity by APTT. When injected in vivo, this fragment gave low blood levels by APTT, very high anti-Xa levels, and was more effective in preventing thrombosis than the decasaccharide fragment. However, in comparison with unfractionated heparin, the 16-18 monosaccharide fragment was only partially effective in preventing thrombosis, despite producing much higher blood levels by anti-Xa assays.It is concluded that the high-affinity binding of a heparin fragment to antithrombin III does not by itself impair venous thrombogenesis, and that the anti-Factor Xa activity of heparin is only a partial expression of its therapeutic potential.

scholarly journals Selective cytotoxicity of 125I-labeled monoclonal antibody T101 in human malignant T cell lines

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 429-435
Author(s):  
E Boven ◽  
T Lindmo ◽  
JB Mitchell ◽  
PA Jr Bunn
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Specific Activity ◽  
Specific Radioactivity ◽  
High Specific Activity ◽  
Tumor Localization ◽  
Cytotoxic Effects ◽  
High Specific Radioactivity ◽  
T Cell Lines

The radiolabeled anti-T cell antibody T101 can be used for specific tumor localization, but unlabeled T101 produces limited cytotoxicity in patients. We thus studied the in vitro cytotoxic effects of T101 labeled with 125I, a radionuclide known for its short-range, high- linear-energy electrons. We showed that 125I-T101 could be readily prepared at high specific activity with high immunoreactivity. Human malignant T cell lines HUT 102, MOLT-4, and HUT 78 were found to differ in the number of T65 determinants (the antigen recognized by T101) and the sensitivity to external x-ray radiation, which were of significance for the cytotoxicity of 125I-T101 in vitro. The cytotoxic effects of 125I-T101 were also found to be dose dependent and increased with exposure time under frozen conditions. As controls, unlabeled T101 had no cytotoxic effect, while free Na 125I or the 125I-labeled irrelevant antibody 9.2.27 exerted minor cytotoxicity. In HUT 102 and MOLT-4, more than 3 logs' cell killing was achieved within four weeks. Because considerable cytotoxicity was demonstrated in vitro by 125I-T101 on T65- positive malignant cells, and because low-dose 111In-T101 can be used successfully for tumor localization, future trials using 125I-T101 at high specific radioactivity may improve therapeutic results in patients with T65-positive malignancies.

scholarly journals STUDIES OF PHOSPHORUS METABOLISM IN MAN: II. A STUDY OF THE PERMEABILITY OF THE HUMAN ERYTHROCYTE TO INORGANIC PHOSPHATE IN VITRO BY THE USE OF RADIOACTIVE PHOSPHATE (P32)

Blood ◽  
1948 ◽  
Vol 3 (12) ◽  
pp. 1472-1477 ◽  
Author(s):  
F. H. L. TAYLOR ◽  
S. M. LEVENSON ◽  
M. A. ADAMS ◽  
MARY KENDRICK
Keyword(s):  
Human Erythrocyte ◽  
Inorganic Phosphate ◽  
Sodium Phosphate ◽  
Specific Activity ◽  
Soluble Fraction ◽  
High Specific Activity ◽  
Phosphorus Metabolism ◽  
Phosphate Exchange ◽  
Inorganic Fraction

Abstract 1. Phosphate exchange in red cells and plasma was studied in vitro using P32 in the form of sodium phosphate as a tracer. 2. No phosphate was added other than the isotopic preparation which was of high specific activity. 3. Inorganic phosphate exchanged freely between the plasma and the erythrocytes at 37.5 C. in a period of four hours. Minimal transfer occurred at 7 C. 4. Most of the added P32 which passed into the erythrocytes during this time remained in the inorganic fraction, less than 15 per cent being found in the organic acid soluble fraction. 5. The specific activity of the inorganic phosphate of the erythrocytes was equal to or greater than that obtaining for the inorganic phosphate of the plasma at the end of the four hour incubation period at 37.5 C.

scholarly journals A New Technic for the Production of an in Vivo Labeled Fibrinogen

Blood ◽  
1967 ◽  
Vol 29 (4) ◽  
pp. 517-525 ◽  
Author(s):  
HENRY GANS ◽  
JAMES MC LEOD ◽  
JAMES T. LOWMAN
Keyword(s):  
Amino Acid ◽  
Specific Activity ◽  
High Specific Activity ◽  
Entire Period ◽  
Turnover Rates ◽  
Prolonged Infusion ◽  
Slow Infusion

Abstract The fact that in vitro labeled proteins, as a rule, exhibit faster turnover rates than in vivo labeled materials led us to explore means of obtaining in vivo labeled fibrinogen of high specific activity. It was found that defibrination of the rat provides a stimulus for the liver to regenerate fibrinogen at an accelerated rate. Administration of seleno75 methionine shortly after thrombin-induced defibrination of the animal resulted in the incorporation of large quantities of the label. The rate of incorporation was further increased if the amino acid was administered as a slow infusion during the entire period of fibrinogen regeneration. In addition, prior nephrectomy of the animal would appear to result in a slight increase in specific activity of the fibrinogen preparation obtained. The results of these studies indicate that defibrination, nephrectomy, and the prolonged infusion of the labeled amino acid selenomethionine provided us with a technic for obtaining a biosynthetically labeled, γ-emitting, fibrinogen preparation of high specific activity.

scholarly journals Separation of the Binding Step from the Collagen Platelet Reaction

1977 ◽  
Author(s):  
P.L. Kronick ◽  
S.A. Jimenez
Keyword(s):  
Type I Collagen ◽  
Specific Activity ◽  
Adenine Nucleotides ◽  
High Specific Activity ◽  
Type Iii Collagen ◽  
Type I ◽  
Type Iii ◽  
Valid Comparison ◽  
Platelet Reaction

Determination of activity of most agents in stimulating platelets to aggregate or release adenine nucleotides is conveniently done by titrating the platelet reaction with the agent. Platelets have previously been titrated with different types of collagen (types I, II, and III) in this way to compare the activities of the collagens. It has been concluded that the order of activity is type III>I>II. Whether this order is due to differences in binding was not obvious from these experiments because the binding was not determined directly. We have developed a method of comparing activities by measuring the targeted dose for each point in the titration - the amount of collagen which actually binds to platelets. The collagens used in these experiments were prepared in vitro from embryonic chick tissue to give labelled products of extremely high specific activity without structural alteration. We find that type I collagen is at least 20 times as active as previously reported, and that the activity of Type III collagen is not significantly higher when the amounts bound are taken into account. The fraction of the labelled tendon collagen which was bound to platelets was identified as type I by its hydroxyproline/proline ratio. Direct measurement of the bound fraction in dose-response studies is required for valid comparison of collagen activities.

Conversion of Flavanone to Flavone, Dihydroflavonol and Flavonol with an Enzyme System from Cell Cultures of Parsley

1981 ◽  
Vol 36 (9-10) ◽  
pp. 742-750 ◽  
Author(s):  
L. Britsch ◽  
W. Heller ◽  
H. Grisebach
Keyword(s):  
Microsomal Fraction ◽  
Specific Activity ◽  
Enzyme System ◽  
High Specific Activity ◽  
Cell Suspension Cultures ◽  
Soluble Enzyme ◽  
Enzyme Preparations ◽  
Malonyl Coa ◽  
In Vitro Biosynthesis

Abstract Soluble enzyme preparations from irradiated cell suspension cultures of parsley (Petroselinum hortense Hoffm.) catalyse the conversion of flavanone to flavone, dihydroflavonol and flavonol. These reactions require 2-oxoglutarate, Fe2+ and ascorbate as cofactors. In the presence of these cofactors conversion of dihydroflavonol to flavonol was also observed. With this system in vitro biosynthesis of radioactive flavone, dihydroflavonol and flavonol from [2-14C]malonyl-CoA and 4-coumaroyl-CoA in good yield and with high specific activity is possible.We postulate that synthesis of flavone and flavonol from flavanone proceeds via 2-hydroxy-and 2,3-dihydroxyflavanone, respectively, with subsequent dehydration.The microsomal fraction of the parsley cells contains an NADPH-dependent flavanone 3'-hydroxylase.

Optimization of Phosphatidylserine-Modified Titanium Surfaces for Enhanced Osteoblast Response

2006 ◽  
Author(s):  
Neera Satsangi ◽  
Arpan Satsangi ◽  
Joo L. Ong ◽  
Rajiv V. Satsangi
Keyword(s):  
Alkaline Phosphatase ◽  
Protein Production ◽  
Specific Activity ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Separate Experiment ◽  
Calcium Deposition ◽  
Fatty Acyl Chain ◽  
Acyl Chain Length

This report is part of a continued effort to evaluate the in vitro osteoblast responses on different phospholipid coatings on Titanium (Ti) implant materials. It has been established that, among analogous phopholipids, the Ti surfaces coated with calcium phosphate (CaP) complex of phosphatidylserine induce the best calcium deposition and osteoblast growth and metabolism. This communication describes an effort to optimize the chemical structure of phosphatidylserine at its position−1 and −2, as Ti surface coating relative to enhancement in osteoblast differentiation and growth in culture. Four synthetic phosphatidylserine analogs with varying fatty acyl chain length and unsaturation were converted to CaP complex, coated on Ti discs, and the osteoblast progenitor cells were cultured on them for up to 14 days to study their differentiation, growth and biochemistry as marked by the expression of alkaline phosphatase specific activity and protein production. In a separate experiment, the topography of the glass surface (glass Petri-dishes) coated the analogous phosphatidylserines, after immersion in simulated body fluid, was examined by scanning electron microscopy (SEM). The presence of calcium and phosphate ions in this deposit was also confirmed. The inclusion of unsaturation in fatty acyl chain in phosphatidylserine enhanced the Total protein production (TPP) as well as the alkaline phosphatase (ALP) specific activity.

Measuring thyroxine and thyrotropin simultaneously in a dried blood sample on filter paper, to screen for neonatal hypothyroidism.

1980 ◽  
Vol 26 (6) ◽  
pp. 750-753
Author(s):  
S Nagataki ◽  
K Ishibashi ◽  
R Ohsawa ◽  
S Suwa ◽  
N Tsukamoto ◽  
...  
Keyword(s):  
Filter Paper ◽  
Specific Activity ◽  
High Specific Activity ◽  
High Sensitivity ◽  
Recall Rate ◽  
Neonatal Hypothyroidism ◽  
High Affinity ◽  
Follow Up Study ◽  
Highly Sensitive

Abstract We have developed a highly sensitive radioimmunoassay of thyroxine and thyrotropin for mass screening for neonatal hypothyroidism. This assay involves a single disc (3 mm diameter) of dried blood on filter paper. The minimum detectable concentrations are 15 pg/tube (10 microgram/L) for thyroxine and 15 nano-int. units/tube (10 milli-int. units/L) for thyrotropin; intra- and interassay CV’s are < 15% in both assays. The high sensitivity of this method is due to use of labeled thyroxine with high specific activity (3 kCi/g) and of an anti-thyrotropin serum with high affinity (Keq = 7.8 × 10(11) L/mol). With this method, 11337 newborns were screened; a follow-up study revealed that only newborns with both high thyrotropin and low thyroxine concentrations had permanent hypothyroidism. We conclude that this method is sensitive, simple, and reliable and that the recall rate with this method is much lower than that of tests for measuring thyroxine or thyrotropin alone.

Copper transport in rats involving a new plasma protein

1985 ◽  
Vol 249 (1) ◽  
pp. E77-E88 ◽  
Author(s):  
K. C. Weiss ◽  
M. C. Linder
Keyword(s):  
Time Course ◽  
Specific Activity ◽  
High Specific Activity ◽  
Apparent Molecular Weight ◽  
Female Rats ◽  
Whole Body ◽  
Peripheral Tissues ◽  
Chelex 100

The time course of distribution of high-specific activity 67CuCl2 to tissues and plasma components was followed in adult, female rats. Immediately after intubation or injection, tracer 67Cu associated with two components of the blood plasma separable on columns of Sephadex G-150: albumin and another (larger) component, which was not ceruloplasmin. The latter, tentatively named transcuprein, had an apparent molecular weight of 270,000 and a high affinity for Cu2+, as judged by processing through Chelex-100, dilution, and exchange with albumin copper, in vitro and in vivo. It was capable of donating copper to tumor cells in serum-free medium. Analysis of "cold" plasma by furnace atomic absorption confirmed the presence of 10-15% of plasma copper in this peak. Plots of percent dose and 67Cu specific activity against time showed that copper followed a very specific pathway after binding to albumin and transcuprein, entering mainly the liver, then reappearing in the plasma on ceruloplasmin, and then achieving peak distribution in peripheral tissues (muscles, brain, etc.). 67Cu disappeared from liver and kidney with an apparent half-life of 4.5 days, the same exponential rate found for whole body turnover. Apparent turnover of ceruloplasmin copper was more rapid. Even after 7-12 days, tracer copper in plasma was still found exclusively with ceruloplasmin. The results indicate that copper follows a carefully prescribed path, on entering the blood and binding to a new transport protein.

Sign in / Sign up

Export Citation Format

Share Document