Opposite clozapine and ziprasidone effects on the reactivity of plasma albumin SH-group are the consequence of their different binding properties dependent on protein fatty acids content.

Antipsychotic drugs interfere with the antioxidant defense system provoking complex and often toxicological effects. Here we examined differences in plasma albumin reduced free thiol (SH) group content and its reactivity as a consequence of clozapine (CLZ) and ziprasidone (ZIP) binding. Chronic administration of CLZ reduced, whereas treatment with ZIP increased albumin-SH content in rats.

The interplay between copper(II), human serum albumin, fatty acids, and carbonylating agent interferes with Cys 34 thiol reactivity and copper binding.

Cys34 thiol group of human serum albumin (HSA) represents major plasma antioxidant. Its reactivity is influenced by multiple factors. The influence of fatty acids (FA; saturated, mono, and poly unsaturated acids from fish oil) binding to HSA, on copper(II) binding affinity and Cys34 thiol group accessibility/reactivity, in the presence of carbonylation agent (methylglyoxal, MG) was examined.

Quantification of total content of non-esterified fatty acids bound to human serum albumin.

Non-esterified fatty acids bound to the human serum albumin (HSA) contribute to several HSAs properties of special concern in pathologies, for instance to the reactivity of the free HSA-Cys34 thiol group (important antioxidative thiol pool in plasma), and to the affinity for binding of molecules and ions (for example cobalt as a prominent biomarker in heart ischemia). Therefore, the method for determination of FAs bound to HSA was developed. FAs were released from HSA (previously isolated from serum by ammonium sulfate precipitation) using acidic copper(II) sulfate in phosphoric acid, extracted by n-heptane-chloroform (4:1, v/v) mixture, spotted on TL silica-gel and then developed with n-heptane-chloroform-acetic acid (5:3:0.

Vitamin D status in mothers with pre-eclampsia and their infants: a case-control study from Serbia, a country without a vitamin D fortification policy.

Objective: The objective of the present study was to determine if vitamin D intake and status are associated with pre-eclampsia in a country without a vitamin D fortification policy.

Design: A case-control study of pregnancies with (case) and without (control) pre-eclampsia was conducted from January to April when UVB is minimal. Maternal and cord blood obtained at delivery were measured for plasma 25-hydroxycholecalciferol (25-OH-D3), 3-epimer of 25-OH-D3 (3-epi-25-OH-D3) and 24,25-dihydroxycholecalciferol (24,25-(OH)2D3) by LC-MS/MS and maternal 1,25-dihydroxyvitamin D (1,25-(OH)2D).

Binding of enterolactone and enterodiol to human serum albumin: increase of cysteine-34 thiol group reactivity.

The interaction of polyphenolic molecules with human serum albumin (HSA) could lead to changes in the reactivity of the HSA Cys34 thiol group (HSA-SH). The influences of enterolactone (EL) and enterodiol (ED) binding on HSA-SH reactivity in fatty acid (FA)-free HSA, and in HSA with bound stearic acid (S) in S/HSA molar ratios of 1:1 and 4:1, were investigated by the determination of the pseudo first order rate constants (k') for the thiol reaction with 5,5'-dithiobis-(2-nitrobenzoic acid). The binding affinities and binding sites of EL and ED were also determined, using fluorescence measurements of the intrinsic fluorescence of Trp214 and diazepam (binding site marker).

HSA carbonylation with methylglyoxal and the binding/release of copper(II) ions.

The potential of carbonylation with methylglyoxal to alter HSA's binding affinity for copper(II) ions and its influence on the release of copper(II) ions from copper-HSA complexes were studied. The affinity of HSA to coordinate copper(II) decreased upon carbonylation of the Cys34-SH group. Carbonylation of copper-HSA complexes caused a decrease in Cys34-SH content, conformational changes and the release of copper(II) ions.

Validity of an FFQ assessing the vitamin D intake of young Serbian women living in a region without food fortification: the method of triads model.

Objective: The objective of the present study was to examine the external validity of an FFQ designed to estimate dietary vitamin D intake compared with a plasma biomarker and three repeated 24 h dietary recalls in women of reproductive age in Serbia, where there is no exposure to food fortified with vitamin D. The method of triads was applied.

Design: In a cross-sectional study, 422 women completed the Women and Reproductive Health FFQ (WRH-FFQ) during the winter months.

Fatty acids binding to human serum albumin: Changes of reactivity and glycation level of Cysteine-34 free thiol group with methylglyoxal.

Fatty acids (FAs) binding to human serum albumin (HSA) could lead to the changes of Cys-34 thiol group accessibility and reactivity, i.e. its scavenger capacity and antioxidant property.

The efficiency of compounds with α-amino-β-mercapto-ethane group in protection of human serum albumin carbonylation and cross-linking with methylglyoxal.

α-Oxoaldehydes, which are produced in higher quantities in diabetes, uremia, oxidative stress, inflammation and aging, react with the amino, guanidine and thiol groups of proteins and cause the formation of advanced glycated end-products and protein cross-linking. To prevent these reactions, the efficiency of low molecular mass thiols with an α-amino-β-mercapto-ethane group (Cys, penicillamine and N-acetylcysteine (NAcCys, with a blocked amino group)) as scavengers of methylglyoxal, compared with glutathione (GSH) and the biguanidine derivative metformin, was investigated. The time courses of the reactions of the aforementioned compounds with methylglyoxal were assayed.

Structural modifications of 4-aryl-4-oxo-2-aminylbutanamides and their acetyl- and butyrylcholinesterase inhibitory activity. Investigation of AChE-ligand interactions by docking calculations and molecular dynamics simulations.

Congeneric set of thirty-eight 4-aryl-4-oxo-2-(N-aryl/cycloalkyl)butanamides has been designed, synthesized and evaluated for acetyl- and butyrylcholinesterase inhibitory activity. Structural variations included cycloalkylamino group attached to C2 position of butanoyl moiety, and variation of amido moiety of molecules. Twelve compounds, mostly piperidino and imidazolo derivatives, inhibited AChE in low micromolar range, and were inactive toward BChE.

The influence of fatty acids on determination of human serum albumin thiol group.

During investigation of the changes of the Cys34 thiol group of human serum albumin (HSA) (isolated by affinity chromatography with Cibacron Blue (CB)) in diabetes, we found that the HSA-SH content was higher (11-33%) than the total serum thiol content. The influence of fatty acids (FA) binding to HSA on this discrepancy was investigated in vitro (using fluorescence and CD spectroscopy and GC) and with HSA samples from diabetic (n=20) and control groups (n=17). HSA-bound FA determine the selection of HSA molecules by CB and enhance reactivity and/or accessibility of the SH group.

Improving the reliability of human serum albumin-thiol group determination.

The thiol (Cys34) content of human serum albumin (HSA-SH) decreases during oxidative and carbonyl stress and, therefore, could represent a useful parameter in clinical practice. Nevertheless, the reliability of HSA-thiol determination with Ellman's method depends on the purity of isolated HSA. Determination of total serum thiols (mmol/L) and HSA-SH content (mmol -SH/mmol HSA) after HSA isolation from diabetic patient and control sera by a two-step precipitation with ammonium sulfate (AS), as well as HSA-SH contribution (%) to total serum thiols, was assessed.

Monitoring of the human serum albumin carbonylation level through determination of guanidino group content.

Carbonylation of the protein amino, guanidine, and thiol groups with α-oxoaldehydes (which are produced in higher quantities in diabetes, uremia, oxidative stress, aging, and inflammation) is one of the important causes of vascular complications. For monitoring of the human serum albumin (HSA) carbonylation level, a spectrophotometric method based on the formation of colored adduct between guanidine group and thymol-sodium hypobromite reagent in the alkaline medium was investigated. Beer's law is obeyed in the concentration range of Arg and protein guanidine groups from 1 to 40 mM.

Chronic isolation stress compromises JNK/c-Jun signaling in rat brain.

The c-Jun NH2-terminal kinases (JNKs) are important stress-responsive kinases. They regulate cellular activities by sequential phosphorylation and activation through a mitogen-activated protein kinase cascade, whereas JNKs activation is altered in response to various stressors. In the present study, we used immunoblotting to assess the effect of 21 day of social isolation as the chronic stressor, either sole and in combination with 2 h of acute immobilization or cold (4°C) stress on circulating corticosterone level and phosphorylation status of p46 (phospho-p46/total p46) and p54 (phospho-p54/total p54) JNK isoforms in the cytosolic and nuclear fraction of the prefrontal cortex and hippocampus of male Wistar rats.

Method for monitoring of the protein amino group changes during carbonylation.

Objectives: Carbonylation of the protein amino, guanidino and thiol groups is one of the important causes of vascular complications in diabetes. We developed a simple spectrophotometric method for monitoring of the changes in the protein amino group contents during carbonylation.

Design And Methods: The method is based on the reaction of amino group with p-benzoquinone in the slightly alkaline media.

Influence of the microenvironment of thiol groups in low molecular mass thiols and serum albumin on the reaction with methylglyoxal.

Methylglyoxal (MG), a reactive alpha-oxoaldehyde that is produced in higher quantities in diabetes, uremia, oxidative stress, aging and inflammation, reacts with the thiol groups (in addition to the amino and guanidino groups) of proteins. This causes protein modification, formation of advanced glycated end products (AGEs) and cross-linking. Low molecular mass thiols can be used as competitive targets for MG, preventing the reactions mentioned above.

4-Aryl-4-oxo-N-phenyl-2-aminylbutyramides as acetyl- and butyrylcholinesterase inhibitors. Preparation, anticholinesterase activity, docking study, and 3D structure-activity relationship based on molecular interaction fields.

Synthesis and anticholinesterase activity of 4-aryl-4-oxo-N-phenyl-2-aminylbutyramides, novel class of reversible, moderately potent cholinesterase inhibitors, are reported. Simple substituent variation on aroyl moiety changes anti-AChE activity for two orders of magnitude; also substitution and type of hetero(ali)cycle in position 2 of butanoic moiety govern AChE/BChE selectivity. The most potent compounds showed mixed-type inhibition, indicating their binding to free enzyme and enzyme-substrate complex.

Acute and/or chronic stress models modulate CuZnSOD and MnSOD protein expression in rat liver.

Cellular protection against oxidative stress is afforded by the enzyme superoxide dismutase (SOD). In this study, the protein levels of copper-zinc SOD (CuZnSOD) in the cytosolic and nuclear fraction, manganese SOD (MnSOD) in the mitochondrial, and cytosolic fraction and cytochrome c (cyt c) in the liver of male rats exposed to 2 h of acute immobilization (IM) or Cold stress, 21 days chronic isolation or their combinations (chronic/acute stress) were examined. The serum corticosterone (CORT) level was measured, as an indicator of stress stimuli.

Serum N-acetyl-beta-D-glucosaminidase profiles in type 1 diabetes secondary complications: causes of changes and significance of determination.

The connection between changes in the activity of serum N-acetyl-beta-D-glucosaminidase (NAG, E.C.3.

Cholinesterase inhibition based determination of pancuronium bromide in biological samples.

Pancuronium bromide (PCBr) inhibition effect on enzyme cholinesterase from pooled human serum (Che, EC 3.1.1.

Influence of pigments and pH of urine on the determination of N-acetyl-beta-D-glucosaminidase activity with 2-methoxy-4-(2'-nitrovinyl)-phenyl-N-acetyl-beta-D-glucosaminide.

The influence of urinary pigments and urine pH on the spectrophotometric determination of N-acetyl-beta-D-glucosaminidase (NAG; EC 3.2.1.

The possibility of determining N-acetyl-beta-D-glucosaminidase isoenzymes under alkaline conditions.

Objectives: To have a reliable diagnostic test, the influence of urine pH on the determination of the total activity of N-acetyl-beta-D-glucosaminidase (NAG) and NAG isoenzyme activities was studied.

Design And Methods: After ultrafiltration and dialysis of the acidic and alkaline urines, the B, A, and A2 forms of NAG were separated by ion-exchange chromatography on DEAE cellulose.

Results: A significant decrease in the total activity of NAG in alkaline urines (pH around 8 or higher) was found, which makes this determination unreliable.

Change in the iso-enzyme profiles of urinary N-acetyl-beta-D-glucosoaminidase in workers exposed to mercury.

The iso-enzyme profiles of urinary N-acetyl-beta-D-glucosoaminidase (NAG) were studied in the workers from a chloro-alkaline electrolysis plant that had been continuously exposed to elemental mercury. The same workers then had a work break of four months and were later re-exposed to mercury for another five months. The activities of urinary NAG in workers exposed to mercury before and after the work break and in the control group were 2.

Simultaneous LC determination of tiazofurin, its acetyl and benzoyl esters and their active metabolite thiazole-4-carboxamide adenine dinucleotide in biological samples.

A rapid and sensitive HPLC-RP method for simultaneous determination of tiazofurin, its 5'-O acetyl and benzoyl esters and their active metabolite thiazole-4-carboxamide adenine dinucleotide was developed and validated. The method allowed determination and quantification of nanomolar quantities of these substances in cell extracts of treated cells, and was also used in kinetic studies of cellular uptake of tiazofurin and its esters from the cultivation medium. Separation of the analyzed substances from unidentified peaks from both biological materials was achieved by gradient elution, thus reducing the possibility of interference.