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Biomedical subjects

M Badea

Publications and source records attributed to M Badea.

13 recordsLinked to original sources
PubMed2005

An electrochemical immunosensor for aflatoxin M1 determination in milk using screen-printed electrodes.

The production and assembling of disposable electrochemical AFM1 immunosensors, which can combine the high selectivity of immunoanalysis with the ease of the electrochemical probes, has been carried out. Firstly immunoassay parameters such as amounts of antibody and labelled antigen, buffer and pH, length of time and temperature of each steps (precoating, coating, binding and competition steps) were evaluated and optimised in order to set up a spectrophotometric enzyme-linked immunosorbent assay (ELISA) procedure. This assay exhibited a working range between 30 and 160 ppt in a direct competitive format. Then electrochemical immunosensors were fabricated by immobilising the antibodies directly on the surface of screen-printed electrodes (SPEs), and allowing the competition to occur between free AFM1 and that conjugated with peroxidase (HRP) enzyme. The electrochemical technique chosen was the chronoamperometry, performed at -100 mV. Furthermore, studies of interference and matrix effects have been performed to evaluate the suitability of the developed immunosensors for the analysis of aflatoxin M1 directly in milk. Results have shown that using screen-printed electrodes aflatoxin M1 can be measured with a detection limit of 25 ppt and with a working range between 30 and 160 ppt. A comparison between the spectrophotometric and electrochemical procedure showed that a better detection limit and shorter analysis time could be achieved using electrochemical detection.

Aflatoxin M1↗
PubMed2001

Antibody-based methods for surfactant screening.

This brief overview summarises the immunoassay-based results obtained in the course of two years of the European INCO-Copernicus project BIOTOOLS. The project is aimed at simplifying the procedures for detection of surface active compounds (SAC) using, among others, antibody-based methods, i.e., microtiter plate-based enzyme-linked immunosorbent assays (ELISA), polarisation fluoro immunoassays (PFIA), and enzyme flow injection immunoassays (FIIA). Thirty-three rabbits were immunised with five different sulphophenyl moieties and three p-hydroxyphenyl moieties conjugated to protein immunogens to produce analytical antibodies against linear alkylbenzene sulphonates (LAS) and nonylphenol (NP). Although most of the antibodies exhibited binding reaction in indirect ELISA, only a few showed the required assay sensitivity. The best antibodies for LAS exhibited a 50% binding inhibition at IC50 19.8 microg L(-1) in indirect ELISA. Similar inhibition was observed for direct ELISA using peroxidase tracers. Antibodies against NP allowed the establishment of an indirect assay operating in the mg L(-1) range. A rapid and simple protocol for the screening of NP and LAS using homogeneous PFIA is described. The assay time for 10 samples was 7 minutes, thus allowing fast detection of the selected SAC at the mg L(-1) level. A generic competitive FIIA system, using a protein G column for separation of free and antibody-bound beta-galactosidase (beta-Gal) tracer, was developed for the screening of LAS, NP, and nonylphenol decaethoxylate (NPEO10). The FIIA had a sample throughput (STP) of 5-10 samples per hour, with limits of detection (LOD) for LAS, NP, and NPEO10 of 19.5, 52, and 2.4 microg L(-1), respectively. The developed FIIAs were applied to spiked rain and surface water.

Animals↗
PubMed2000

Flow analysis for determination of paraoxon with use of immobilized acetylcholinesterase reactor and new type of chemiluminescent reaction.

A highly sensitive flow analysis method for determination of acetylcholinesterase (AChE) inhibitors like organophosphorous pesticides using a new chemiluminescent reaction was developed and optimized. This method is fast, sensitive, and cheap, because it requires only one enzyme and its substrate. The system incorporates a reactor with immobilized AChE on controlled pore glass (CPG) and a chemiluminometric detector. Variations in enzyme activity due to inhibition are measured from the changes of concentrations of thiocholine produced when the substrate (acetylthiocholine chloride) is pumped before and after the passage of the solution containing the pesticide through the immobilized AChE reactor. Thiocholine is determined by a new chemiluminescent reaction with luminol in the presence of potassium ferricyanide. The percentage inhibition of enzyme activity is correlated to the pesticide concentration. The inhibited enzyme is reactivated by 10 mM pyridine-2-aldoxime methiodide (2-PAM). The experimental conditions were first optimized for activity determination of the effect of pH, flow rates, and Tris concentrations. For the measurement of AChE inhibition, the appropriate concentration of the substrate is selected such that the rate of noninhibited reaction can be considered unchanged and could be used as a reference. For optimization of experimental conditions for inhibition, several parameters of the system are studied and discussed: flow rate, enzyme-pesticide contact time, luminol concentration, ferricyanide concentration, 2-PAM concentration, and configuration of the FIA manifold. Paraoxon, an organophosphorous pesticide was tested. For an inhibition time of 10 min the calibration graph is linear from 0.1 to 1 ppm paraoxon with a relative standard deviation (n = 5) of 4.6% at 0.5 ppm. For an inhibition time of 30 min the calibration graph is linear from 25 to 250 ppb paraoxon.

Acetylcholinesterase↗
PubMed1998

Cervical intraepithelial neoplasia and HPV infection.

Human papillomavirus (HPV) infection has been recognized as the major cause of cervical cancer [1]. The transformation zone of the cervix is the most frequent target of the high risk HPV types. In our study infection with HPV16 and 18 was investigated in the cervical scrapes of 28 subjects with cervical intraepithelial neoplasia. The DNAs isolated from the samples were amplified by dot-blot hybridization with fragmented digoxygenin labelled probes. Eighteen of 28 patients (64.3%) were found positive for HPV-16, eleven (39.3%) were found positive for HPV-18 and six patients (21%) were infected with both HPV types. This method is practical and sensitive for determining patients with a higher risk of developing HPV-related cancer.

Adolescent↗
PubMed1992

Commentary: the public health consequences of restricted induced abortion--lessons from Romania.

The question of whether abortion should be legal is currently being decided in many countries. Although much of the discussion has focused on ethical issues, the public health consequences should not be overlooked and should be addressed realistically and responsibly. Nowhere are the public health manifestations of restricted abortion more apparent than in Romania. The pronatalist policies of the Ceaucescu regime resulted in the highest maternal mortality rate in Europe (approximately 150 maternal deaths per 100,000 live births) and in thousands of unwanted children in institutions.

Abortion, Illegal↗
PubMed1991

[IgA changes in chronic alcoholic hepatopathy].

Chronic alcoholic hepatitis (CAH) has been included, in the last 10 years, among the disease accompanied by particular changes of IgA (primary glomerulonephritis with mesangial deposits of IgA, Berger; Henoch-Schonlein's purpura with IgA deposits in dermatic capillaries and herpetiform dermatitis, with deposits of IgA in dermatic papillae). The characteristics of IgA involvement in CAH are: The whole IgA system is changed, at its 3 levels: circulatory, tissular, formative. at the circulatory level, the IgA2 monomeric fraction increases characteristically; in hepatic parenchyma, perisinusoidal linear deposits of IgA are formed; they have a great significance for the alcoholic etiology, the length of time and seriousness of alcoholism.

Chronic Disease↗
PubMedDate not supplied

Flow injection system with chemiluminometric detection for enzymatic determination of ascorbic acid.

A simple, selective and rapid method for determination of ascorbic acid from fruit juices was developed by combining a flow injection analysis (FIA) system with a chemiluminometric detector and a reactor with L-ascorbate oxidase immobilized on controlled pore glass. It was found that some reducing agents (eg ascorbic acid and mercaptoacetic acid) give chemiluminescence with luminol in the presence of hexacyanoferrate (III) in an alkaline solution. We used this new type of chemiluminescent reaction for the enzymatic determination of ascorbic acid. The background substraction method was used in order to avoid interference during ascorbic acid determination. Accordingly, two chemiluminometric signals were registered for each determination, one signal corresponding to the sample that passed through the enzymatic reactor that decomposed the ascorbic acid completely, and the second signal corresponding to the sample that does not pass through the reactor. The difference between the two signals corresponds to ascorbic acid from the sample. The linear range of the method was 10-1000 micromol/L of ascorbic acid and the detection limit was 5 micromol/L The throughput was four samples/h and RSD 3.13% (n = 10). This method was applied for determination of ascorbic in fruit juices. The results were compared with those found by the reference method, based on titrimetric determination with 2,6-dichlorophenolindophenol, and the concordance was excellent.

Ascorbate Oxidase↗
PubMedDate not supplied

Experimental modulation of the plasmalemmal microfluidity. Studies on endothelial and aortic smooth muscle cells.

The microfluidity of cell membranes has been modified experimentally in endothelial cells and smooth muscle cells of bovine or monkey aorta cultured in vitro. Microfluidity was estimated by fluorescence depolarization measurements of diphenyl-hexatriene (DPH)-labelled cells. In both types of cells investigated, the arachidonic acid at concentration of 90 microM induced an increase in the microfluidity by 26-53% whereas the cholesterol at the same concentration produced a decrease in the microfluidity by 16-25%. The oleic acid in the range of 30 to 90 microM increased the monkey smooth muscle cell membranes microfluidity by 21-33% but did not change the microfluidity of endothelial and bovine aortic smooth muscle cells. The stearic acid did not influence the microfluidity of either type of cells under investigation. Cortisol at 90 microM changed the microfluidity of the bovine aortic endothelial cells plasmalemma depending on the incubation time. Possible factors of error in the physical measurements due to the extracellular localization of DPH have been identified.

Animals↗
PubMedDate not supplied

Drug allergy: incidence in terms of age and some drug allergens.

The authors studied the incidence of drug allergy in 3 groups of subjects. In the first group the incidence was established in terms of the subjects' age: 1.8% in children up to 14 years old (323 subjects), 5.8% in middle-aged subjects (389 subjects) and 2.9% in the elderly (243 subjects). In the second partly selected group, drug allergy was studied in patients admitted to the 3rd Medical Clinic--Craiova between 2 Jan. 1981 and 31 Dec. 1982; 103 of the 8,760 patients admitted presented allergic reactions, a relatively high incidence rate (1.01%) as compared to other published reports. The third group of previously selected cases consisted of 197 patients who had come to the allergology service with complaints of present or past sensitivity to drugs. The total number of patients was 336 selected or preselected from about 10,000 subjects, to which 17 patients with a diagnosis of "asthmatic triad" must be added. Drug allergy in terms of the drug used was dominated by penicillin, pyramidon-algocalmin, aspirin, iodine preparations, etc.; foremost among the clinical syndrome were the dermatologic syndromes types I, III and IV; syndromes of the "anaphylactic shock" type, "serum sickeness" bronchial asthma, angioneurotic oedema.

Adolescent↗