Search results for "Assay"
showing 10 items of 2241 documents
Cost-Effectiveness Analysis of Different Testing Strategies that Use Antibody Levels to Detect Chronic Hepatitis C in Blood Donors.
2016
Aim. We conducted a cost-effectiveness analysis of seven hepatitis C virus (HCV) testing strategies in blood donors. Methods. Three of the seven strategies were based on HCV diagnosis and reporting guidelines in Mexico and four were from previous and current recommendations outlined by the CDC. The strategies that were evaluated determine antibody levels according to the signal-to-cut-off (S/CO) ratio and use reflex Immunoblot (IMB) or HCV RNA tests to confirm true positive (TP) cases of chronic HCV infection. Costs were calculated from the perspective of the Mexican Institute of Social Security (IMSS). A decision tree model was developed to estimate the expected number of true positive cas…
Home-based HIV testing: Using different strategies among transgender women in Argentina.
2019
Background In Argentina, HIV prevalence among transgender women (TGW) has been reported at 34%. The stigma is one of the most important factors limiting their access to healthcare services. The aims of this study were to compare different HIV testing methodologies, to determine the factors associated with HIV diagnosis and to determine the feasibility of a home-based HIV testing service for TGW. Methods A multidisciplinary team performed home-based HIV testing interventions in four cities of Argentina. Participants self-identified as TGW, older than 14 years and with a negative or unknown HIV status. Blood samples were screened by two rapid tests (RT), one based on antibodies (Determine™ HI…
Anti-prothrombin autoantibodies enriched after infection with SARS-CoV-2 and influenced by strength of antibody response against SARS-CoV-2 proteins
2021
Antiphospholipid antibodies (aPL), assumed to cause antiphospholipid syndrome (APS), are notorious for their heterogeneity in targeting phospholipids and phospholipid-binding proteins. The persistent presence of Lupus anticoagulant and/or aPL against cardiolipin and/or β2-glycoprotein I have been shown to be independent risk factors for vascular thrombosis and pregnancy morbidity in APS. aPL production is thought to be triggered by–among other factors–viral infections, though infection-associated aPL have mostly been considered non-pathogenic. Recently, the potential pathogenicity of infection-associated aPL has gained momentum since an increasing number of patients infected with Severe Acu…
Recombinant human erythropoietin increases the radiosensitivity of xenografted human tumours in anaemic nude mice
2001
Purpose: The effect of recombinant human erythropoietin (Epo) on the radiosensitivity of human tumour xenografts growing in anaemic nude mice was studied. Methods and materials: Anaemia was induced by total body irradiation (TBI) of mice prior to tumour transplantation. The development of anaemia was prevented by Epo (1000 U/kg s.c.) given 3 times weekly starting 2 weeks prior to TBI (5 Gy). Epo treatment did not influence the growth rate of the tumours, which were transplanted into the subcutis of the hind leg of mice. Thirteen days after TBI (tumour volume of approx. 40 mm3), a single-dose irradiation (12 Gy) of the tumour was performed resulting in a growth delay with subsequent regrowth…
The radiosensitization effect of titanate nanotubes as a new tool in radiation therapy for glioblastoma: A proof-of-concept
2013
Abstract Background and purpose One of the new challenges to improve radiotherapy is to increase the ionizing effect by using nanoparticles. The interest of titanate nanotubes (TiONts) associated with radiotherapy was evaluated in two human glioblastoma cell lines (SNB-19 and U87MG). Materials and methods Titanate nanotubes were synthetized by the hydrothermal treatment of titanium dioxide powder in a strongly basic NaOH solution. The cytotoxicity of TiONts was evaluated on SNB-19 and U87MG cell lines by cell proliferation assay. The internalization of TiONts was studied using Transmission Electron Microscopy (TEM). Finally, the effect of TiONts on cell radiosensitivity was evaluated using …
A radiosensitizing effect of artesunate in glioblastoma cells is associated with a diminished expression of the inhibitor of apoptosis protein surviv…
2011
Abstract Background and purpose Novel strategies to overcome an irradiation resistant phenotype may help to increase therapeutic efficacy in glioblastoma multiforme. The present study aimed to elucidate radiation sensitizing properties of artesunate, a semi synthetic derivate of artemisinin and to assess factors involved in this effect. Materials and methods LN229 and U87MG cells were treated with various concentrations of artesunate and radiation response was determined by a colony forming assay. Cell numbers, apoptosis induction, cell cycle distribution, and DNA repair following combined modality treatment were monitored by MTT-, caspase 3/7 assay, cytofluorometry, and γ-H2AX foci formati…
Mechanisms of interference of p-diphenols with the Trinder reaction
2020
p-Diphenols, such as homogentisic acid, gentisic acid, etamsylate, and calcium dobesilate, interfere with diagnostic tests utilizing the Trinder reaction but the mechanisms of these effects are not fully understood. We observed substantial differences both in oxidation of p-diphenols by horseradish peroxidase and their influence on oxidation of 4-aminoantipyrine and various phenolic substrates. Homogentisic acid was rapidly oxidized by the enzyme and completely blocked chromophore formation. Enzymatic oxidation of the remaining p-diphenols was slow and they only moderately inhibited chromophore formation. However, in the presence of standard substrates all tested p-diphenols were rapidly co…
Cytotoxicity, antibacterial and physicochemical properties of a new epoxy resin-based endodontic sealer containing calcium hydroxide
2019
Background This study evaluated the cytotoxicity, antibacterial and physicochemical properties of a new epoxy resin-based endodontic sealer containing calcium-hydroxide Sealer Plus. AH Plus was used as a reference for comparison. Material and Methods Cytotoxicity evaluation was performed according to ISO-10993-5 specifications using MTT assay to check the 3T3 cells viability at 1- to 4-week periods. Antibacterial activity was evaluated using a direct contact test against Enterococcus faecalis. Radiopacity, solubility and flow evaluations were performed according to ISO-6876/2012 specifications. Setting time was assessed following the ANSI/ADA-standard-n.57. The pH level was measured at 3,24…
Probing human beta1- and beta2 -adrenoceptors with domain-specific fusion protein antibodies.
1997
In order to generate antibodies suitable for immunological studies on beta-adrenoceptors constitutively expressed at low levels in cells or tissues we have produced fusion proteins of the amino- and carboxy-terminus, and the second extracellular loop of the human beta 1- or beta 2-adrenoceptors with bacterial glutathione-S-transferase in E. coli. Rabbit antibodies raised against these fusion proteins strongly reacted with intact human beta 1- or beta 2-adrenoceptors in a subtype- and domain-specific manner. Antibodies directed against the second extracellular loop of the beta 1-adrenoceptor reacted stronger with non-denatured receptors and decreased the affinity of the 3H-labelled antagonis…
Pre- and Post-translational Regulation of Lysyl Oxidase by Transforming Growth Factor-β1 in Osteoblastic MC3T3-E1 Cells
1995
The final enzymatic step required for collagen cross-linking is the extracellular oxidative deamination of peptidyl-lysine and -hydroxylysine residues by lysyl oxidase. A cross-linked collagenous extracellular matrix is required for bone formation. The goals of this study were to compare the transforming growth factor (TGF)-beta 1 regulation of lysyl oxidase enzyme activity and steady state mRNA levels to changes in COL1A1 mRNA levels in MC3T3-E1 osteoblastic cells. TGF-beta 1 increased steady state lysyl oxidase and COL1A1 mRNA levels in a dose- and time-dependent manner. The increase in lysyl oxidase mRNA levels was transient, peaking at 12 h and 8.8 times controls in cells treated with 4…