Search results for "Chemiluminescence"
showing 10 items of 86 documents
Mechanism of activated chemiluminescence of cyclic peroxides: 1,2-dioxetanes and 1,2-dioxetanones
2017
Almost all chemiluminescent and bioluminescent reactions involve cyclic peroxides. The structure of the peroxide and reaction conditions determine the quantum efficiency of light emission. Oxidizable fluorophores, the so-called activators, react with 1,2-dioxetanones promoting the former to their first singlet excited state. This transformation is inefficient and does not occur with 1,2-dioxetanes; however, they have been used as models for the efficient firefly bioluminescence. In this work, we use the SA-CASSCF/CASPT2 method to investigate the activated chemiexcitation of the parent 1,2-dioxetane and 1,2-dioxetanone. Our findings suggest that ground state decomposition of the peroxide com…
Diagnostic accuracy of cerebrospinal fluid biomarkers measured by chemiluminescent enzyme immunoassay for Alzheimer disease diagnosis.
2020
In the last decades, an important role of cerebrospinal fluid (CSF) biomarkers for Alzheimer disease (AD) diagnosis has emerged. The evaluation of the triad consisting of 42 aminoacid-long amyloid-beta peptide (Aβ42), total Tau (tTau) and Tau phosphorylated at threonine 181 (pTau) have been recently integrated into the research diagnostic criteria of AD. For a long time, the enzyme-linked immunosorbent assay (ELISA) has represented the most commonly used method for the measurement of CSF biomarkers levels. This study aimed to assess the diagnostic accuracy of CSF biomarkers, namely Aβ42, tTau and pTau and their ratio, measured by fully automated CLEIA assay (Lumipulse). We included 96 patie…
Inference of SARS-CoV-2 spike-binding neutralizing antibody titers in sera from hospitalized COVID-19 patients by using commercial enzyme and chemilu…
2021
medRxiv: https://doi.org/10.1101/2020.09.07.20188151
Evaluation of Anti-SARS-Cov-2 S-RBD IgG Antibodies after COVID-19 mRNA BNT162b2 Vaccine
2021
(1) Background: The evaluation of anti-spike protein receptor-binding domain (S-RBD) antibodies represents a useful tool to estimate the individual protection against Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection
Taking up the cudgels for the traditional reactive oxygen and nitrogen species detection assays and their use in the cardiovascular system
2017
Reactive oxygen and nitrogen species (RONS such as H2O2, nitric oxide) confer redox regulation of essential cellular functions (e.g. differentiation, proliferation, migration, apoptosis), initiate and catalyze adaptive stress responses. In contrast, excessive formation of RONS caused by impaired break-down by cellular antioxidant systems and/or insufficient repair of the resulting oxidative damage of biomolecules may lead to appreciable impairment of cellular function and in the worst case to cell death, organ dysfunction and severe disease phenotypes of the entire organism. Therefore, the knowledge of the severity of oxidative stress and tissue specific localization is of great biological …
Polyoxypregnanes as safe, potent, and specific ABCB1-inhibitory pro-drugs to overcome multidrug resistance in cancer chemotherapy in vitro and in vivo
2021
Multidrug resistance (MDR) mediated by ATP binding cassette subfamily B member 1 (ABCB1) is significantly hindering effective cancer chemotherapy. However, currently, no ABCB1-inhibitory drugs have been approved to treat MDR cancer clinically, mainly due to the inhibitor specificity, toxicity, and drug interactions. Here, we reported that three polyoxypregnanes (POPs) as the most abundant constituents of Marsdenia tenacissima (M. tenacissima) were novel ABCB1-modulatory pro-drugs, which underwent intestinal microbiota-mediated biotransformation in vivo to generate active metabolites. The metabolites at non-toxic concentrations restored chemosensitivity in ABCB1-overexpressing cancer cells v…
Multivariate standardisation for non-linear calibration range in the chemiluminescence determination of chromium.
2006
Multivariate standardisation is proposed for the successful chemiluminescence determination of chromium based on luminol-hydrogen peroxide reaction. In an extended concentration range, non-linear calibration model is needed. The studied instrumental situations were different detection cells, instruments, assemblies, time and their possible combinations. Chemiluminescence kinetic registers have been transferred using piecewise direct standardisation (PDS) method. The optimisation of transfer parameters has been carried out based on the prediction residual error criteria. Non-linear principal component regression (NL-PCR) and non-linear partial least square regression (NL-PLS) were chosen for…
Correlation of the chemiluminescence-activity of peripheral blood monocytes with CSF parameters of inflammation and the clinical course of patients w…
2009
– The chemiluminescence-activity (CL-A) of peripheral blood monocytes (MO) was measured in eight patients with lymphocytic meningitis or meningoencephalitis and compared to CSF parameters and the clinical course. The initial maximum CL-A was around four times above the control and decreased to normal values within approximately 20 days. Poor correlations were found when the CL-A was compared to CSF parameters in the total group of patients. With regard to the CSF parameters in individual patients the CL-A was closely related to the cell count, to a lesser degree to the protein content, but not to the IgG content. Finally, a very good correlation of the CL-A was found with the clinical cours…
The behaviour of OKT3-, OKT4- and OKT8-positive cells during phases of elevated spontaneous chemiluminescence activity (CL-A) in multiple sclerosis p…
1987
The chemiluminescence activity (CL-A; synonym = burst activity, BA) and the percentage of OKT3-, OKT4- and OKT8-positive peripheral blood cells were serially examined in four control persons and in eight patients with multiple sclerosis. When the OKT values obtained in phases of increased CL-A (clinical remission) were compared with those of the control group, the percentage of OKT3-positive cells was reduced (P = 0.014), and that of OKT4-positive cells increased (P = 0.014); there were no significant changes in the percentage of OKT8-positive cells (P = 0.171). After the CL-A had returned to normal values, the OKT4-positive cells remained elevated (P = 0.029), whereas the OKT3- (P = 0.342)…
Determination of nitrite by inhibition of the chemiluminescence of acriflavine in a flow-injection assembly
2001
The indirect determination of nitrite was performed with a flow-injection assembly on the basis of the inhibition of the analytical output obtained in a luminometer by oxidation of acriflavine. The acriflavine solution merged with the nitrite and the resulting mixture was injected into a pure water stream. This solution merged with the oxidant solution (potassium permanganate in sulfuric acid medium) and the resulting chemiluminiscence was affected (inhibited) by the presence of nitrite after reaction with the aminoacridine. The method was applicable over the range 10–800 μg l−1 of nitrite with a correlation coefficient of 0.9960. The relative standard deviation was 1.4% and the throughput …