Search results for "IMMUNOASSAY"
showing 10 items of 266 documents
Secretion and antigenicity of hepatitis B virus small envelope proteins lacking cysteines in the major antigenic region.
1995
Abstract Disulfide bonds are of crucial importance for the structure and antigenic properties of the hepatitis B virus (HBV) envelope. We have evaluated the role of the eight highly conserved cysteines of the major antigenic region for assembly, secretion, and antigenicity of the envelope proteins. Mutants carrying single or multiple substitutions of alanine for cysteine were analyzed using epitope tagging and transient expression in COS-7 cells. The only single cysteines found to be indispensable for efficient secretion were Cys-107 and Cys-138, but double mutation of Cys-137 and Cys-139 also created a block to secretion. Poorly secreted mutants formed aberrant oligomeric structures. The a…
Detection of the synthetic drug 4-fluoroamphetamine (4-FA) in serum and urine.
2010
Abstract 4-Fluoroamphetamine (4-FA) was detected in the blood and urine of two individuals suspected for driving under the influence (DUI). The test for amphetamines in urine subjected to immunoassay screening using the CEDIA DAU assay proved positive. Further investigations revealed a 4-FA cross-reactivity of about 6% in the CEDIA amphetamine assay. 4-FA was qualitatively detected in a general unknown screening for drugs using GC/MS in full scan mode. No other drugs or fluorinated phenethylamines were detected. A validated GC/MS method was established in SIM mode for serum analysis of 4-FA with a limit of detection (LOD) of 1 ng/mL and a lower limit of quantification (LLOQ) of 5 ng/mL. Int…
Novel M. tuberculosis specific IL-2 ELISpot assay discriminates adult patients with active or latent tuberculosis
2018
Background Tuberculosis (TB) still is a major worldwide health problem, with 10.4 million new cases in 2016. Only 5–15% of people infected with M. tuberculosis develop TB disease while others remain latently infected (LTBI) during their lifetime. Thus, the absence of tests able to distinguish between latent infection and active tuberculosis is one of the major limits of currently available diagnostic tools. Methods A total of 215 patients were included in the study as active TB cases (n = 73), LTBI subjects (n = 88) and healthy persons (n = 54). Peripheral blood mononuclear cells (PBMCs) were isolated from each patient and the LIOSpot® TB anti-human IL-2 ELISpot assay was performed to test …
A class-selective immunoassay for simultaneous analysis of anilinopyrimidine fungicides using a rationally designed hapten
2017
he development of multianalyte immunoassays constitutes a main research issue in the field of bioanalytical techniques. In the present study, class-specific antibodies against the three members of the anilinopyrimidine family of fungicides (pyrimethanil, cyprodinil and mepanipyrim) were raised by using a bioconjugate of a rationally designed hapten [5-(6-methyl-2-(phenylamino)pyrimidin-4-yl)pentanoic acid]. Highly sensitive immunoassays were developed for the generic determination of these compounds, using the competitive enzyme-linked immunosorbent assay (ELISA). Particularly, a direct antibody-coated competitive ELISA afforded identical sensitivity for the three anilinopyrimidines, with I…
Enzyme and lateral flow monoclonal antibody-based immunoassays to simultaneously determine spirotetramat and spirotetramat-enol in foodstuffs.
2021
Spirotetramat is employed worldwide to fight insect pests due to its high efficiency. This chemical is quickly metabolized by plants into spirotetramat-enol, so current regulations establish that both compounds must be determined in foodstuffs for monitoring purposes. Nowadays, immunochemical methods constitute rapid and cost-effective strategies for chemical contaminant analysis at trace levels. However, high-affinity binders and suitable bioconjugates are required. In this study, haptens with opposite functionalisation sites were synthesized in order to generate high-affinity monoclonal antibodies. A direct competitive enzyme-linked immunosorbent assay with an IC50 value for the sum of sp…
Combined heterologies for monoclonal antibody-based immunoanalysis of fluxapyroxad
2018
Nowadays, instrumental methodologies and rapid bioanalytical techniques complement each other for the analysis of toxic chemical compounds. Fluxapyroxad was commercialized a few years ago as a fungicide and today it is being used worldwide to control a variety of pests. In the present study, the development of monoclonal antibody-based immunochemical methods for the analysis of this chemical in food samples was evaluated for the first time. Novel haptens were synthesized and protein bioconjugates were prepared. High-affinity and specific monoclonal antibodies to fluxapyroxad were generated from two haptens with alternative linker tethering sites. Haptens with linker site heterology and a st…
Hepatic steatosis and insulin resistance are associated with severe fibrosis in patients with chronic hepatitis caused by HBV or HCV infection.
2011
BACKGROUND AND AIMS: Steatosis and insulin resistance (IR) are the major disease modifying in patients with chronic hepatitis C (CHC). Only few studies evaluated these features in patients with chronic hepatitis B (CHB). We aimed to assess the prevalence and the factors related to steatosis and IR in CHB patients, compared with CHC subjects, and to evaluate the potential association between these features and fibrosis severity. MATERIAL AND METHODS: One hundred and seventy consecutive patients with CHB (28 HBeAg positive, 142 HBeAg negative), were evaluated using liver biopsy and metabolic measurements and matched for sex, age and body mass index with 170 genotype 1 CHC patients. IR was def…
Implication of corticotropic hormone axis in eating behaviour pattern in obese and type 2 diabetic participants.
2015
In Algeria, eating behaviour has been increasingly deviated from its traditional Mediterranean diet to modern fast food style. The present study examines the interactions between eating behaviour pattern (EBP), corticotropic hormone axis and the metabolic syndrome. Our Algerian population cohort comprised of 410 participants (130 obese, 170 type 2 diabetics and 110 healthy participants). The EBP was evaluated by the Three-Factor Eating Questionnaire test. The anthropometric and metabolic parameters (glucose, TAG, HDL, LDL and cholesterol) and the concentrations of hormones (insulin, adrenocorticotropin hormone (ACTH), cortisol and growth hormone) were determined by biometrics, spectrophotom…
Differences in non-MHC restricted cytotoxic activities of human peripheral blood lymphocytes after transfusion with allogeneic leukocytes or platelet…
1990
Abstract MHC-unrestricted cytotoxic activity of peripheral blood lymphocytes (PBL) from 4–6 healthy donors was investigated before and after transfusion with allogeneic leukocytes or platelets. Natural killer and lectin-dependent cellular cytotoxicity (LDCC) of PBL was tested against K562 and Raji target cells in a 4-h and 16-h 51 Cr-release assay, respectively. After allotransfusion with leukocytes, we found increased cytotoxic activity of each donor's PBL against all the three targets on day 3 or 7. The highest non-specific cytotoxic activity was detected against the relatively NK resistant Raji target cells. The increase of cytotoxic activity was lowest against the LDCC target (PHA-treat…
Cyclooxygenase-1/2 (COX-1/COX-2) and 5-lipoxygenase (5-LOX) inhibitors of the 6,7-diaryl-2,3-1H-dihydropyrrolizine type
2003
A series of 6,7-diaryl-2,3-1H-dihydropyrrolizines was prepared as COX-1/COX-2 and 5-LOX inhibitors. The inhibition of COX-1 was evaluated using intact bovine platelets as the enzyme source, whereas LPS-stimulated human monocytes served as the enzyme source for inducible COX-2. The determination of arachidonic metabolites was performed by HPLC for COX-1 and RIA for COX-2. The balance between COX-1/COX-2 and 5-LOX inhibition can be shifted by modifying the substitution pattern of the phenyl moiety at the 6- and 7-position of the pyrrolizine nucleus. Structure-activity relationships are discussed.