Use Of Immunochemical Methods Research Articles

Analysis of total aflatoxins in commercially available cereal products in the Republic of North Macedonia

Aflatoxins, as naturally occurring toxins, can accumulate in maturing crops or in grain during transportation and represent serious threat for contamination of cereal processed products. Consumption of aflatoxin contaminated foodstuffs can cause acute or chronic toxicity in humans. With an aim to protect public health, maximum residue levels (MRLs) for these toxins are defined by the regulation authorities. To control the compliance of aflatoxin residues in cereal-based products to legislation, a convenient analytical technique that will provide rapid, specific, accurate and costly effective analysis such as ELISA method is required. In this study, concentration of total aflatoxins in twelve cereal processed products supplied under random selection from several retail outlets in Republic of North Macedonia was determined using commercially available RIDASCREEN Aflatoxin total kit. Analyses have shown that none of the examined samples contained aflatoxins above the MRLs (4 μg/kg). According to the obtained results, the ELISA method can be used for routine detection and quantification of total aflatoxins in cereal products due to simplicity, specificity and sensitivity. In addition, this study may initiate the use of immunochemical methods for analysis of potential aflatoxin contamination in order to establish data collection for the presence of these concerning toxins in cereal-based products available on the national market. Keywords: aflatoxins, ELISA, immunochemical, cereals

ABH blood group antigens in N-glycan of human glycophorin A

We previously showed that a small proportion of the O-linked oligosaccharide chains of human glycophorin A (GPA) contains blood group A, B or H antigens, relevant to the ABO phenotype of the donor. The structures of these minor O-glycans have been established (Podbielska et al. (2004) [20]). By the use of immunochemical methods we obtained results indicating that ABH blood group epitopes are also present in N-glycan of human GPA (Podbielska and Krotkiewski (2000) [22]). In the present paper we report a detailed analysis of GPA N-glycans using nanoflow electrospray ionization tandem mass spectrometry. N-glycans containing A-, B- and H-related sequences were identified in GPA preparations obtained from erythrocytes of blood group A, B and O donors, respectively. The ABH blood group epitopes are present on one antenna of the N-glycan, whereas a known sialylated sequence NeuAcα2-6Galβ1-4GlcNAc- occurs on the other antenna and other details are in agreement with the known major structure of the GPA N-glycan. In the bulk of the biantennary sialylated N-glycans released from GPA preparations, the blood group ABH epitopes-containing N-glycans, similarly O-glycans, constituted only a minor part. The amount relative to other N-glycans was estimated to 2–6% of blood group H epitope-containing glycans released from GPA-O preparations and 1–2% of blood group A and B epitope-containing glycans, released from GPA-A and GPA-B, respectively.

The analytical environmental immunochemical consortium

The Analytical Environmental Immunochemical Consortium (AEIC) is a relatively new organization, established with the aim of promoting the use of immunochemical methods as recognized analytical tools for food and environmental testing. The members of AEIC include immunoassay kit manufacturers, agricultural and basic chemical manufacturers, immunoassay equipment manufacturers and commercial, government and academic laboratories involved in the research and development of non‐clinical immunochemical technology.

Application of immunological methods for the determination of environmental pollutants in human biomonitoring. A review

Human biomonitoring (HBM) is gaining increasing popularity in occupational and environmental health in order to assess individual chemical exposure. It involves the determination of an exposure marker such as a parent chemical and/or its metabolite(s) in selected tissues, expired breath, body fluids such as blood, or excreta. HBM can provide accurate information on absorption resulting from all routes of exposure. Because of the complexity of biological samples, in many cases tedious extraction and clean-up procedures are necessary to isolate analytes for classical wet chemical and instrumental analysis. In the clinical laboratory practice a modern approach is the use of immunochemical methods (immunoassays). These methods proved to be sensitive, fairly simple, and cost-effective alternatives or supplementations to existing highly sophisticated analytical methods. An increasing supply of commercialized immunoassay kits for environmental contaminants such as pesticides and industrial chemicals can be obtained. This paper reviews the application of immunochemical methods for the determination of environmental chemicals as exposure markers of internal dose in biological samples of human origin only. Applications have been reported for pesticides and trace contaminants. Both radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) formats have been applied, making use of polyclonal and monoclonal antibodies. Most of the reviewed methods are adequately sensitive for HBM. Validation of immunoassay performance is frequently made by intercomparison tests or fortification of samples. Usually, more polar analytes could be measured with reduced or no sample preparation. Especially with hydrophobic chemicals such as dioxins and PCBs extraction and sample clean-up were necessary to reduce interferences by matrix constituents. Only few assays have been applied to the measurement of pollutants in samples of occupationally or accidentally exposed human beings.

Variations in embryospecific globulins of human blood sera in foetuses and the newborn.

THE use of immunochemical methods for studying the composition of foetal human blood serum proteins led to the discovery of, in addition to the known alpha foetoprotein1–8, other embryospecific globulins with electrophoretic mobility of beta1 (refs. 5, 6, 9) and beta2 globulins9. Alpha foetoprotein is a relatively constant component of foetal blood serum. Embryospecific beta1 globulin was discovered in about 75 per cent9,10 and embryospecific beta2 globulin in 50 per cent of the cases9.

The use of immunochemical methods in embryology, particularly in the study of lens development in the chick

The formation of lens proteins during chick embryo development was studied by the immunoelectrophoretic and Ouchterlony techniques. 1. With antiserum against adult chicken lens, no lens antigen was demonstrable in 24-hr and 36-hr embryo extracts, nor in 48-hr embryo head and trunk extracts. 2. With antiserum against 5-day embryo lens, it was equally impossible to demonstrate lens antigen in 24-hr and 36-hr embryo extracts and 48-hr embryo head and trunk extracts. 3. With antiserum against adult chicken lens, the earliest lens antigen demonstrated was in a 60-hr embryo head extract; it was lacking in the trunk extract. 4. With antiserum against 5-day embryo lens, the carliest lens antigen demonstrated was also in a 60-hr embryo head extract; it was not present in the trunk extract. 5. With antiserum against 5-day embryo lens, a serum antigen was demonstrated in 24-hr and 36-hr embryo extracts, in 48-, 60- and 72-hr embryo head and trunk extracts, and in 5-day embryo lens extracts. 6. With antiserum against 24-hr embryo extract, at least 3 serum components and 2 egg-yolk components were demonstrated in 24-hr embryo extract. 7. In egg yolk, several serum proteins and at least one typical vitelline component were demonstrated.

The use of Immunochemical Methods in Studies on Proteins

Publisher Summary The chapter discusses the use of immunochemical methods in studies on proteins. The main value of immunochemical methods is that they are specific and sensitive. It is also known that the specificity of the antigen–antibody reaction is because of the spatial configuration of some chemical groupings in the antigen molecule. The chapter explores the main advantages of the immunoelectrophoretic analysis:(1) its simplicity, (2) the possibility of analyzing very complex mixtures, (3) each of the components can be defined or identified by its electrophoretic mobility. The advantages as well as the limitations of immunochemical methods are because of the use of a specific reagent, the antibody. The chapter deals with the aspects of this problem, which have a direct connection with the use of antibodies as reagents in the precipitin reactions. Because these reagents are formed in animals receiving injections of antigens, the main problem is the way to provoke the formation of precipitating antibodies in a conveniently chosen animal at a maximal concentration. A very large spectrum of biochemical research problems can be approached by the use of immunochemical methods. For simplification, the problems are classified arbitrarily into three groups: static or descriptive biochemistry, alterations or modifications of proteins, and structural problems.