The tau protein is one of the neurocytoskeletal proteins that participate in the pathogenesis of serious neurological diseases, especially Alzheimer's disease. The tau protein is characterized by ...considerable structural variability, which is reflected in the existence of its numerous proteoforms. This review aims to provide brief information on the structure of tau protein and its proteoforms, which seem promising biomarkers for clinical use. Biological fluids, suitable for laboratory examination in clinical practice, i.e., cerebrospinal fluid and blood (plasma/serum), are discussed. Total tau protein and its phosphorylated forms (mainly the pT181-tau protein, phosphorylated at the threonine residue 181) have already found clinical application in diagnosis of Alzheimer's disease.
Abstract The role of humoral immunity related to neuron- and disease-specific cytoskeletal proteins patients with Alzheimer disease (AD) is unknown. We measured antibodies against tau protein, light ...and heavy (NFH) neurofilaments using ELISA in 80 paired serum and cerebrospinal fluid (CSF) samples from patients with AD, with other dementias (OD), with neuro-inflammatory diseases (IC) and 25 controls (NC). We estimated intrathecal synthesis according to the formula (CSF/serum anti-neurocytoskeletal IgG)/(CSF/serum total IgG). AD patients had significantly higher intrathecal anti-tau and anti-NFH antibodies than the other groups. These innovative findings may hint at specific alterations in humoral anti-neurocytoskeletal immunity and selectivity in AD, which could have diagnostic and immunotherapeutic implications.
Food fraud has been and still is a problem in the food industry. It is detectable by several approaches, such as high performance liquid chromatography (HPLC), chemometric assays, or DNA-based ...techniques, each with its own drawbacks. This work addresses one major drawback of DNA-based methods, in particular their sensitivity to inhibitors contained in particular matrices from which DNA is isolated. We tested five commercial kits and one in-house method characterized by different ways of sample homogenization and DNA capture and purification. Using these methods, DNA was isolated from 10 different fruit species commonly used in plant-based foodstuffs. The quality of the DNA was evaluated by UV-VIS spectrophotometry. Two types of qPCR assays were used for DNA quality testing: (i) Method specific for plant ITS2 region, (ii) methods specific for individual fruit species. Based mainly on the results of real-time PCR assays, we were able to find two column-based kits and one magnetic carrier-based kit, which consistently provided fruit DNA isolates of sufficient quality for PCR-based assays useful for routine analysis and identification of individual fruit species in food products.
Alcohol-induced oxidative stress is linked to the metabolism of ethanol. Three metabolic pathways of ethanol have been described in the human body so far. They involve the following enzymes: alcohol ...dehydrogenase, microsomal ethanol oxidation system (MEOS) and catalase. Each of these pathways could produce free radicals which affect the antioxidant system. Ethanol per se, hyperlactacidemia and elevated NADH increase xanthine oxidase activity, which results in the production of superoxide. Lipid peroxidation and superoxide production correlate with the amount of cytochrome P450 2E1. MEOS aggravates the oxidative stress directly as well as indirectly by impairing the defense systems. Hydroxyethyl radicals are probably involved in the alkylation of hepatic proteins. Nitric oxide (NO) is one of the key factors contributing to the vessel wall homeostasis, an important mediator of the vascular tone and neuronal transduction, and has cytotoxic effects. Stable metabolites – nitrites and nitrates – were increased in alcoholics (34.3 ± 2.6 vs. 22.7 ± 1.2 µmol/l, p < 0.001). High NO concentration could be discussed for its excitotoxicity and may be linked to cytotoxicity in neurons, glia and myelin. Formation of NO has been linked to an increased preference for and tolerance to alcohol in recent studies. Increased NO biosynthesis also via inducible NO synthase (NOS, chronic stimulation) may contribute to platelet and endothelial dysfunctions. Comparison of chronically ethanol-fed rats and controls demonstrates that exposure to ethanol causes a decrease in NADPH diaphorase activity (neuronal NOS) in neurons and fibers of the cerebellar cortex and superior colliculus (stratum griseum superficiale and intermedium) in rats. These changes in the highly organized structure contribute to the motor disturbances, which are associated with alcohol abuse. Antiphospholipid antibodies (APA) in alcoholic patients seem to reflect membrane lesions, impairment of immunological reactivity, liver disease progression, and they correlate significantly with the disease severity. The low-density lipoprotein (LDL) oxidation is supposed to be one of the most important pathogenic mechanisms of atherogenesis, and antibodies against oxidized LDL (oxLDL) are some kind of epiphenomenon of this process. We studied IgG oxLDL and four APA (anticardiolipin, antiphosphatidylserine, antiphosphatidylethanolamine and antiphosphatidylcholine antibodies). The IgG oxLDL (406.4 ± 52.5 vs. 499.9 ± 52.5 mU/ml) was not affected in alcoholic patients, but oxLDL was higher (71.6 ± 4.1 vs. 44.2 ± 2.7 µmol/l, p < 0.001). The prevalence of studied APA in alcoholics with mildly affected liver function was higher than in controls, but not significantly. On the contrary, changes of autoantibodies to IgG oxLDL revealed a wide range of IgG oxLDL titers in a healthy population. These parameters do not appear to be very promising for the evaluation of the risk of atherosclerosis. Free radicals increase the oxidative modification of LDL. This is one of the most important mechanisms, which increases cardiovascular risk in chronic alcoholic patients. Important enzymatic antioxidant systems – superoxide dismutase and glutathione peroxidase – are decreased in alcoholics. We did not find any changes of serum retinol and tocopherol concentrations in alcoholics, and blood and plasma selenium and copper levels were unchanged as well. Only the zinc concentration was decreased in plasma. It could be related to the impairment of the immune system in alcoholics. Measurement of these parameters in blood compartments does not seem to indicate a possible organ, e.g. liver deficiency.
Abstract A release of light neurofilament subunits (NFL) into cerebrospinal fluid (CSF) and serum in multiple sclerosis (MS) may induce an immune response. We examined CSF and serum NFL levels and ...IgG antibodies against NFL in 19 patients with a clinically isolated syndrome (CIS) early converted into MS, 20 CIS-non-converters, 23 MS patients and 32 controls. CSF NFL levels were significantly higher in all patient groups. The highest CSF or intrathecally (IT) synthesized anti-NFL antibodies and CSF/serum ratios of anti-NFL antibodies were observed in CIS-converters. CSF NFL and CSF or IT anti-NFL antibodies could be surrogate biomarkers of axonal injury in early MS.
Antibodies against tau protein indicate an interaction between the immune system and the neurocytoskeleton and therefore may reflect axonal injury in multiple sclerosis (MS).
The levels and avidities ...of anti-tau IgG antibodies were measured using ELISA in paired cerebrospinal fluid (CSF) and serum samples obtained from 49 MS patients and 47 controls. Anti-tau antibodies were significantly elevated intrathecally (p<0.0001) in the MS group. The CSF anti-tau antibody levels were lower in MS patients receiving therapy than those without treatment (p<0.05). The avidities of anti-tau antibodies were higher in the CSF than in the serum (MS group p<0.0001; controls p<0.005). Anti-tau avidities in the CSF were elevated in MS patients in comparison with controls (p<0.05), but not in serum.
MS patients have higher levels of intrathecal anti-tau antibodies. Anti-tau antibodies have different avidities in different compartments with the highest values in the CSF of MS patients.
Background
Avidity of antiphospholipid antibodies may be clinically useful as a valuable additional characteristic. The aim of this study was to compare several ELISA modifications with different ...chaotropic agents and calculation of avidity indices for the determination of anticardiolipin antibody (aCL) avidity.
Methods
We examined 28 serum samples with positive IgG aCL by adapted ELISA using various concentrations of urea and sodium chloride as chaotropic agents and different dilution of sera. We tested these conditions of ELISA—a single diluted serum sample with fixed concentration of a chaotrope and a serially diluted serum in the constant concentration of a chaotropic agent.
Results
We demonstrated that ELISA method for avidity determination based on a single dilution of serum in the presence of fixed concentration of chaotrope is convenient for determination of IgG aCL antibody avidity. Concentrations 6 and 8 mol/L of urea or 1 and 2 mol/L of NaCl were suitable for sufficient dissociation of immune complexes during ELISA procedure.
Conclusion
This way was in good agreement with more demanding procedures. Both urea and sodium chloride may be used as chaotropic agents. Reference values of avidity indices essential for interpretation of patients’ results must be established individually for distinct assay conditions.
Abstract Heavy neurofilaments (NFH) released from neurons during axonal injury induce a humoral immune response. We measured CSF and serum levels of NFH proteins and anti-NFH IgG antibodies in 19 ...patients with clinically isolated syndrome (CIS) converting to multiple sclerosis, in 20 stable CIS patients, 23 patients with multiple sclerosis (MS) and 32 control subjects using ELISA. CSF and intrathecal levels and CSF/serum ratios of anti-NFH antibodies were increased in the CIS patients early developing MS while NFH protein concentrations were similar among the groups. Changes associated with NFH are more pronounced for antibodies than for protein itself and may aid in prediction of CIS patients.
Antiphosphatidylethanolamine antibodies (aPE) represent one type of antiphospholipid antibody (aPL) directed against the neutral phospholipids - phosphatidylethanolamines. The aim of this study was ...to evaluate levels and avidities of aPE in several groups of patients and compare them with conventional aPLs.
aPE were analysed in a cohort consisting of 68 hospitalized patients. The other cohort comprised 22 patients with immunologically-mediated diseases. The control group consisted of 20 healthy persons. ELISA methods were used for determination of aPL. Avidities of aPE were tested by modified ELISA with urea as a chaotropic agent.
aPE IgG/IgM were significantly higher in the group of patients with venous thromboembolism than those with non-thrombotic internal disorders (P=0.02 for both Ig classes). aPE IgG/IgM elevated above cut-off values were found in 10.8% of patients with venous thromboembolism and as a single aPL in 6.5%. Levels of aPE IgG higher than our limit (>6 U/mL) were detected in 29% of patients with immunologically-mediated diseases with other positive aPL. Low-, intermediate- and high-avidity aPE IgG were found in patients of both cohorts. The avidities of aPE IgG differed from those of anticardiolipin antibodies IgG. Neither aPE IgG levels nor avidity dynamics significantly changed during follow-up.
aPE may be related to venous thromboembolism and may be part of the repertoire of aPL in immunologically-mediated diseases. There are patients with thrombosis negative for conventional aPL but positive for aPE. aPE IgG may have different avidities.
The article deals with a brief description of methods of temperature measurements in a flowing water steam. Attention is paid to the measurement of pseudo static temperature by a single sealed ...thermocouple entering the flowing liquid through the flown-by wall. Then three types of probes for stagnation temperature measurement are shown, whose properties were tested using CFD calculations. The aim was to design a probe of stagnation parameters of described properties which can be used for measuring flow parameters in a real steam turbine. An important factor influencing the construction is not only the safe manipulation of the probe when inserting and removing it from the machine in operation, but also the possibility to traverse the probe along the blade length.
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