New adjuvant design using layered double hydroxide for production of polyclonal antibodies in radioimmunoassay techniques

Various adjuvants have been used to enhance the immune response against specific antigens. So the objective of this work describes the immune stimulating activity of layered double hydroxide (LDH) particles incorporate with mineral oil as a new formulation of adjuvant as compared to known Freund’s adjuvant for production of alpha-fetoprotein polyclonal antibody (anti-AFP) for estimation of alpha fetoprotein (AFP) in human serum by radioimmunoassay technique. In this concern, the study comprised two groups of white New Zealand rabbits, 2?2.5 kg body weight and each group comprised three rabbits. The first group vaccinated with AFP antigen emulsified with Freund’s adjuvant and the second group vaccinated with AFP antigen emulsified with LDH formulation. The obtained data show that the highest displacement using LDH adjuvant reached (74.2, 61.7 and 66.5 %) while the corresponding values with Freund’s adjuvant recorded (64.8, 60.3 and 54.6 %) which indicates that the use of LDH adjuvant as a cellular vehicle is a more suitable choice. Also, the preparation of AFP tracer using lactoperoxidase oxidation method and its purification using gel chromatography on PD-10 column were carried out. Different factors affecting the optimization of the assay process were studied. Validation testes of the assay were carried out. The reproducibility as measured by the intra- and inter- assay variations is satisfactory. The recovery and dilution testes indicated accurate calibration and appropriate matrix. The present technique agreed well with the currently used commercial kit (Siemens, IRMA kit). In conclusion, the liquid phase double antibody RIA technique proved to be sensitive, specific, precis and accurate for routine laboratory use.     

Ultratrace analysis and isotope ratio measurements of long-lived radioisotopes by resonance ionization mass spectrometry (RIMS)

Resonance Ionization Mass Spectrometry (RIMS) is a sensitive and selective method for ultratrace analysis of long-lived radioisotopes and isotope ratio measurements. It provides extremely high isobaric suppression and good overall efficiency. The experimental limits of detection are as low as 10⁶ atoms per sample and isotopic selectivities of 5×10¹² have been obtained. The widespread potential of RIMS, using different experimental arrangements, is demonstrated for the determination of the radiotoxic isotopes Pu-238 to Pu-244 and Sr-89/Sr-90 in various environmental samples as well as for Ca-41 in nuclear reactor components and biomedical samples.     

Development of a Flow Immunoassay System for the Detection of Salmonella Typhimurium

Abstract

A flow immunoassay system has been developed for the detection of Salmonella typhimurium by immobilization of antibody to Salmonella onto tygon tubing by adsorption and onto polyethylene tubing, by covalent binding. After liquid containing Salmonella cells or Salmonella antigen was allowed to interact with the immobilized. antibody, glucose oxidase labeled antibody to Salmonella was injected to the system. The bound antigen was quantified by electrochemical detection of H₂O₂ produced from the enzymic oxidation of glucose to gluconic acid. In view of the low non-specific binding, sensitivity and reusability, the polyethylene immunoreactor provided a better performance. The system was capable of detecting as low as 10⁵ ? 10⁶ Salmonella cells/ml in less than 10 minutes. The immunoreactor could be regenerated for at least 50 times during one month of the experiment. The detection limit of the tygon immunoreactor was somewhat higher (10⁶ ? 10⁹ cells/ml). Even though the anti-Salmonella antibody was easily immobilized on the tygon tubing, the system was not reusabl and exhibited a very high non-specific binding.     

Cross reactivity between human erythropoietin antibody and horse erythropoietin

Erythropoietin (EPO) is the primary hormone of erythropoiesis. Administration of recombinant human erythropoietin (rhuEPO) to improve racing performance in the horse represents a new form of blood doping, which has been associated with increased mortality. While immunoassay kits have become plentiful, very few commercial hormone assays are made specifically for equine research. There is a strong degree of sequence homology reported for EPO among species, which has allowed antibodies designed for human EPO research to be used to determine EPO concentration in other species. The objective of the present study was to use Western blot analysis to determine whether the antibody to rhuEPO, provided in a commercial radioimmunoassay (RIA) kit, recognizes horse EPO. Western blot analysis of purified rhuEPO and horse plasma was conducted, using the polyclonal goat-antihuman EPO antibody supplied in the Incstar EPO Trac RIA as the primary antibody. Immunoblot analysis revealed a major band at approximately 52 kDa for both rhuEPO and the horse plasma. Our results demonstrate that a human EPO antibody recognizes equine EPO. These findings show that the Incstar EPO Trac RIA hormone assay system can be used to measure equine EPO.     

Human proinsulin. C-peptide radioimmunoassay method. 125I labeling of human proinsulin. C-petide

125I-labelled human-C-peptide was prepared by chloramin T method, enzymic method and active ester method, respectively. Using respective 125I-labelled human-C-peptides in human proinsulin-C-peptide RIA, we compared the binding (Bo/T%) to antibody, displacement by standard human-C-peptide, the recovery test and stability. The usable 125I-labelled antigen for human proinsulin-C-peptide RIA could be prepared by chloramin T method and enzymic method wich labelled 125I to tyrosyl human proinsulin connecting peptide, and active ester method which conjugates 125I-labelled active ester to human proinsulin connecting peptide. The differences among those 125I-labelled antigens was not observed in displacement (B/Bo%) by standard human-C-peptide and the recovery test. In the case of constant preparation of 125I-labelled antigen for RIA, the enzymic method was the best from the viewpoint the reaction ratio is stable and stability of Bo/T% is good.     

High-performance liquid chromatographic procedure for specificity testing of radioimmunoassays: rolipram.

A high-performance liquid chromatographic (HPLC) procedure for testing the specificity of radioimmunoassays (RIA) was developed using the same method of extraction as in the RIA, followed by fractionation of the extract by HPLC and subsequent measurement of cross-reactions in all the fractions according to the normal RIA procedure. The RIA of rolipram, an antidepressant drug, was checked in plasma samples obtained from pharmacokinetic studies in rats, rabbits, cynomolgus monkeys and humans. The antibody was shown to be specific in the plasma samples from the laboratory animals, but not in human plasma. This was because in human plasma a metabolite occurred with a structure similar to that used for the hapten in the immunization process. This metabolite was not found in the plasma of the animal species investigated. The test procedure described is generally applicable, making the time-consuming development of an alternative method such as gas chromatography-mass spectrometry unnecessary.     

Syntheses of 2,4,6-tris(di-tetrahydrofurfuroxy)phosphinyl-s-triazine and its derivatives as fire-retardants for cellulose

The synthesis of 2,4,6-tris(di-tetrahydrofurfuroxy)phosphinyl-s-triazine (2) was achieved by the reaction of cyanuric chloride with tris(tetrahydrofurfuryl)-phosphite (1) or with sodium bis(tetrahydrofurfuryl)phosphite (5). 2 on treatment with anhydrous ammonia yielded ammonium salt of 2,4-diamino-6-tetrahydro-furfuroxy-phosphinyl-s-striazine (3), which on methylolation yielded (4). The reaction of 2 and 4 with cellulose powder under different experimental conditions was carried out and they were found to exhibit promising fire-retardant properties.     

Duryne,a new cytotoxic agent from the marine sponge Cribrochalinadura

Duryne, 1, a cytotoxic metabolite which inhibits the growth of both mouse and human tumor cell lines invitro has been isolated from the marine sponge Cribrochalinadura. Its structure has been assigned by spectral methods.     

Comparison Between Two Assays for Plasma Cortisol

Abstract

We have compared the results obtained for plasma cortisol when two methods were used to measure this steroid. The first method, a Competitive protein binding (CPB) assay, used transcortin as binding protein for cortisol. The second method is a radioimmunoassay (RIA) utilizing as binding reagent, a specific antibody against cortisol. Nineteen samples were tested covering a wide range of values. The CPB assay consistently overestimated the levels of plasma cortisol compared to the RIA method.     

Total synthesis of lipoxin B: assignment of stereochemistry

Four isomers of lipoxin B were synthesized using carbohydrate precursors. An authentic sample of lipoxin B (from human leukocytes) was found to be a mixture of all-trans isomers 1a and 1c.     

Factors controlling electron transfer reactions and stabilisation of uncommon oxidation states of chromium

Some experimental approaches to seek semi-quantitative understanding of factors controlling outer sphere electron transfer reactions of some transition metal complexes have been made. The relative importance of nuclear and electronic factors to outer sphere processes has been examined. By the manipulation of Franck-Condon or nuclear factors, it has now been possible to gain access into the chemistry of chromium in unusual oxidation states. An example of a reorganisation controlled electron transfer reaction involving Cr(IV)-Cr(III) system has been demonstrated. The bimolecular rate of reduction of diperoxoaquaethylenediamine chromium(IV) and diperoxodiethylenetriamine chromium(IV) is independent of the nature of th reductant employed viz. Fe²⁺ or VO²⁺ indicating that the generation of6 coordinate Cr(IV) species from7 coordinate of diperoxochromium(IV) reactant may be rate limiting. Similarly by increasing the barrier for the6 coordinate to4 coordinate structures through equatorial coordination of macrocyclic ligands, it has now been possible to detect through cyclic voltommogram the formation of relatively stable Cr(IV) species in the electrochemical oxidation of Cr(Me₄[14] tetraene)(H₂O) ₂ ³⁺ in aqueous sulphuric acid media. The kinetics and mechanism of the cerium(IV) and iodosyl benzene oxidation of Cr(salen)(H₂O) ₂ ⁺ and Cr(salprn)(H₂O) ₂ ⁺ have been investigated and kinetic and spectroscopic evidence for the formation of Cr(IV) transients and stable Cr(V) products has been presented. The relative importance of Franck-Condon factors in the oxidation of Cr(III) to Cr(IV) and Cr(V) states in different macrocyclic and multidentate ligand environments has been discussed.     

A secondary antibody format chemiluminescence immunoassay for the determination of estradiol in human serum

A competitive immunoassay for estradiol (E2) based on secondary antibody format was established. The donkey anti-rabbit IgG was used as the secondary antibody to coat micro-plates, and the horseradish peroxidase (HRP)-luminol-H₂O₂ chemiluminescent system with high sensitivity was chosen as the detection system. The addition of sodium trichloroacetate (CCl₃COONa) in the enzyme buffer as a replaceable packing material can realize directly analysis of E2 in human serum without extraction, which improved reproducibility and resolution of the assay. Additionally, the method showed specific recognition of estrogen, without cross-reaction for the major steroids (estrone (E1), estriol (E3), dihydrotestosterone (DHT), androstenedione, testosterone (T)) commonly found in human serum. The chemiluminescence immunoassay with secondary antibody can be applied to detect E2 with good precision at concentrations as low as 1.48 pg mL⁻¹. The proposed method has been successfully applied to the determination of E2 in 97 human sera and showed a good correlation compared with the commercially radioimmunoassay (RIA) kit with a correlative coefficient of 0.9881. This method has exhibited great potential in the fabrication of diagnostic kit and can be used in the clinical analysis of E2 in human serum.     

A Fluorometric Assay of L-Aspartate: 2-oxoglutarate Aminotransferase in Human Serum with N-(9-Acridinyl) maleimide

Abstract

A new assay of L-aspartate:2-oxoglutarate aminotransferase (EC 2, 6, 1, 1) (glutamic-oxaloacetic transaminase: GOT) is reported. Substrate L-aspartate was replaced with L-cysteine sulfinic acid (CSA) which yields sulfite and pyruvate. The enzyme activity was determined by measuring the sulfite with the aid of a fluorescent reagent, N-(9-acridinyl)maleimide (NAM). The method presents a extremely sensitive GOT assay in the range of 4 to 140 U/l using less than 10 μl of human serum.     

Combined High-Performance Liquid Chromatography and Radioimmunoassay for A Novel Retinobenzoic Acid Derivative, 4-[(5,6,7,8-Tetrahydro-5,5,8,8-Tetramethyl-2-Naphthyl)-Carbamoyl] Benzoic Acid (AM-80), in Human Plasma

Abstract

4-[(5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)-carbamoyl] benzoic acid (Am-80) is a novel retinobenzoic acid derivative possessing retinoid activity. Plasma concentration of this drug in clinical use is very low, less than 1 ng/ml, and could not be measured with direct immunoassays. A combination of high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA) was developed for this drug in human plasma. Am-80 in 0.5 ml of human plasma was extracted by solid-phase extraction, and the extract was purified by reversed-phase HPLC. The immunoreactivity in the fraction of the eluate was measured by competitive RIA. The within- and between-assay variances were 4.1 to 15.5% and 4.1 to 7.0%, respectively. The limit of quantification was 0.04 ng/ml in human plasma, which was much lower than that of direct RIA, 0.6 ng/ml, previously reported. This assay system could be used to observe the pharmacokinetics of Am-80 in human even after dermal application at very low dose.     

Models of folate cofactors 18. Application in an approach to the synthesis of indoloquinolizine alkaloids

The substituted 5,10-methylenetetrahydrofolate models 5b and 7, prepared by the addition of glutaconate ester anion to 1-acetyl-3,4,4-tri-methyl-2-imidazolinium iodide (2b) and 1-acetyl-3-aethyl-1,4,5,6-tetrahydro-pyrimidinium iodide (3) transfer the C(2)-carbons with the attached functional groups to give an indole derivative which serves as a convenient precursor for the synthesis of nor-deplancheine (21) and nor-epigeissoschizoate (27).     

Raman-spectrum investigation of the conformations of cis-and trans-1,3-dimethylcyclohexanols

Summary When configurations are named with respect to the actually largest substituents, the preferred conformation for the compound (I) in the liquid phase is trans-1e3a, and for compound (II) in the liquid phase cis-1e3e with equatorial hydrogen-bonded hydroxyls; when this nomenclature, based on the actually largest substituents is used, the Auwers-Sktta rule is not reversed for the compounds (I) and (II) in the liquid state.     

Towards a multi-electrode array (MEA) system for patterned neural networks

Here we describe the development of a unique multi-electrode array (MEA) system capable of supporting patterned neural networks in vitro. The significant features of this BioMEMS system are: (1) precise and exclusive positioning of the neural cell bodies to the electrode region, (2) definition of interconnecting pathways among the neurons by using patterned self-assembled monolayers (SAMs), and (3) one-to-one stimulation and recording from precisely positioned neurons. We present for the first time the design and fabrication of an MEA chip supporting patterned neuronal networks, as well as the initial electrical recordings from two types of neurons.     

Interatomic distances in molecules of gaseous alkali metal halides

Summary One of the possible methods of comparative calculation was used for calculating interatomic distancesd in gaseous alkali halides. The average deviation of the calculated values ofd from experimental values was 0.0012 A (for 15 substances).Translated from Zhurnal Strukturnoi Khimii, Vol. 1, No. 4, pp. 399–403, November–December, 1960     

Saturated heterocycles 115: Cycloaddition of nitrilimine and nitrile oxide to norbornane- and norbornene-fused dihydro-1,3-oxazines

By cycloaddition of nitrilimine and nitrile oxide to diexo and diendo norbornane- and norbornene-fused structural isomeric dihydro-1,3-oxazlnes (1-3), tetracyclic 1,3-oxazino-1, 2,4-trlazolines (7-9) and 1,2,4-oxadiazolines (10-12) were obtained. With norbornehe dipolarophiles, which contain a C=N and a C=C bond, the cycloaddition takes place at the olefinic bond and the diexo compound 4 yields 13 regioselectively, whereas the diendo isomer 5 gives an Isomeric mixture of isoxazolines 14 and 15. From the diexo derivative 6, however, a bis-adduct 16 is formed. The stereostructures of the adducts have been elucidated by NMR spectroscopy.