Serum levels of leptin and adiponectin in patients with autoimmune Hashimoto's thyroiditis.

INTRODUCTION: Adipose tissue is immunologically and hormonally active, and these effects are mediated largely by adipocytokines. Thyroid hormones regulate metabolism and organ function, and Hashimoto's thyroiditis (HT) is the most common autoimmune disease affecting thyroid function. AIM: To evaluate the levels of the adipocytokines leptin and adiponectin in patients with autoimmune HT, and to perform a comparative intragroup analysis in patients with different stages of gland functional activity, and in a control group. MATERIALS AND METHODS: Ninety-five patients with HT and 21 healthy controls were enrolled in the study. Venous blood was taken without anticoagulants after at least 12 hours of fasting, and serum samples were frozen at -70°C until analysis. Serum levels of leptin and adiponectin were determined by an enzyme-linked immunosorbent assay (ELISA). RESULTS: Serum levels of leptin in HT patients were higher than those in the control group (4.5±5.2 ng/mL vs. 1.9±1.3 ng/mL). The hypothyroid patient's group showed significantly higher levels of leptin than those of the healthy controls (5.1±5.2 ng/mL vs. 1.9±1.3 ng/mL), (p=0.031). Leptin levels correlated positively with body mass index (r=0.533, p.

Use of a Hydrophobic Azo Dye for the Centrifuge-Less Cloud Point Extraction-Spectrophotometric Determination of Cobalt.

The hydrophobic azo dye 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR, H2L) was studied as part of a system for the centrifuge-less cloud point extraction (CL-CPE) and spectrophotometric determination of traces of cobalt. The extracted 1:2 (Co:HTAR) complex, [CoIII(HL-)(L2-)]0, shows an absorption maximum at 553 nm and contains HTAR in two different acid-base forms. Optimum conditions for its formation and CL-CPE were found as follows: 1 × 10-5 mol L-1 of HTAR, 1.64% of Triton X-114, pH of 7.8, incubation time of 20 min at ca. 50 °C, and cooling time of 30 min at ca. -20 °C. The linear range, limit of detection, and apparent molar absorptivity coefficient were 5.4-189 ng mL-1, 1.64 ng mL-1, and 2.63 × 105 L mol-1 cm-1, respectively. The developed procedure does not use any organic solvents and can be described as simple, cheap, sensitive, convenient, and environmentally friendly. It was successfully applied to the analysis of artificial mixtures and real samples, such as steel, dental alloy, rainwater, ampoules of vitamin B12, and saline solution for intravenous infusion.

Spectrophotometric Determination of Molybdenum(VI) as a Ternary Complex with 4-Nitrocatechol and Benzalkonium Chloride.

A new liquid-liquid extraction system for molybdenum(VI) was studied. It contains 4-nitrocatechol (4NC) as a complexing chromogenic reagent and benzalkonium chloride (BZC) as a source of heavy cations (BZ+), which are prone to form chloroform-extractable ion-association complexes. The optimum conditions for the determination of trace molybdenum(VI) were found: concentrations of 4NC and BZC (7.5 × 10-4 mol dm-3 and 1.9 × 10-4 mol dm-3, respectively), acidity (3.75 × 10-2 mol dm-3 H2SO4), extraction time (3 min), and wavelength (439 nm). The molar absorptivity, limit of detection, and linear working range were 5.5 × 104 dm3 mol-1 cm-1, 5.6 ng cm-3, and 18.6-3100 µg cm-3, respectively. The effect of foreign ions was examined, and the developed procedure was applied to the analysis of synthetic mixtures and real samples (potable waters and steels). The composition of the extracted complex was 1:1:2 (Mo:4NC:BZ). Three possible structures of its anionic part [MoVI(4NC)O2(OH)2]2- were discussed based on optimizations at the B3LYP/3-21G level of theory, and simulated UV/Vis absorption spectra were obtained with the TD Hamiltonian.

Phase separation liquid-liquid extraction for the quantification of 8-iso-Prostaglandin F2 Alpha in human plasma by LC-MS/MS.

BACKGROUND: Reactive oxygen species (ROS) are produced in the body during normal metabolism by means of enzymes and non-enzymatic chemical reduction of molecular oxygen. In case of the prevalence of ROS formation over their elimination, highly reactive free radicals can be accumulated and can cause multiple damages to the biomolecules and cells. Determination of isoprostanes in biological matrices is most often used to register free radical damage and requires selective, sensitive and specific techniques. METHODS: This study presents the development and validation of the LC-MS/MS method for the determination of 8-iso-Prostaglandin F2α in human plasma utilising a modified liquid-liquid extraction procedure with phase separation. RESULTS: Modified sample preparation procedure assured higher extraction yield, clear separation of organic layer from the plasma water phase and protein precipitates, and better-purified product for instrumental analysis. Linearity was validated in the range 0.1-5.0 µg/L with R2 > 0.996; normalised matrix varied between 86.0% and 108.3%, accuracy ranged from 90.4 % to 113.9% and precision both within runs and between runs was less than 7%. With a run time of 10 min, a throughput of over 50 samples per working day could be performed. CONCLUSIONS: The method meets all the current industrial validation criteria and allows the accurate and precise determination of 8-iso-PGF2α in human plasma at diagnostically significant concentration range.

Study on the Complex Formation and the Ion-Association of Anionic Chelate of Molybdenum(VI) with Bidentate Ligand and the Cation of 2,3,5-Triphenyl-2?-tetrazolium Chloride.

The complex formation between the anionic chelate of molybdenum(VI) with the bidentate ligand of 3,5-dinitrocatechol (3,5-DNC) and its ion-association with the cation of 2,3,5-triphenyl-2?-tetrazolium chloride (TTC) in the liquid-liquid extraction system Mo(VI)?3,5-DNC?TTC?H2O?CHCl3 were studied by spectrophotometry. The validity of Beer's law was checked and some analytical characteristics of the system were calculated under the optimum conditions for the chelate formation and extraction. The effect of various co-existing ions and reagents on the process of chelate formation and ion-association was investigated. The molar ratio of the components in the ion-associated complex Mo(VI)-3,5-DNC-TTC was determined by independent methods. The association process in aqueous phase and the extraction equilibria were investigated and quantitatively characterized by the following equilibrium constants: association constant, distribution constant, extraction constant and recovery factor. Based on this, a reaction scheme, a general formula and a structural formula of the complex were suggested.

Study on the Chelate Formation and the Ion-association of Anionic Chelate of Molybdenum(VI) with 3,5-Dinitrocatechol and Monotetrazolium Cation.

The equilibria of the chelate formation and ion-association in the liquid-liquid extraction system Mo(VI)‒3,5-DNC‒INT‒H2O‒CHCl3 were studied by spectrophotometry. The optimum conditions for the chelate formation and extraction of the ion-associated complex formed between the anionic chelate of Mo(VI)‒3,5-dinitrocatechol (3,5-DNC) and the cation of 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) were established. The validity of Beer's law was checked and some analytical characteristics were calculated. The effect of various co-existing ions and reagents on the process of complex formation was investigated. The molar ratio of the components in the ternary ion-associated complex Mo(VI)-3,5-DNC-INT was determined by independent methods. The association process in aqueous phase and the extraction equilibria were investigated and quantitatively characterized. The following key constants of the processes were calculated: association constant, distribution constant, extraction constant and recovery factor. Based on this, a reaction scheme, a general formula and a structure of the complex were suggested.

Study on the Equilibria of the Complex Formation of the Ion-pair of Germanium(IV) with 4-Nitrocatechol and 1,4-Diphenyl-3-(phenylamino)-1H-1,2,4-triazole.

The complex formation of the ion-pair formed between the anionic chelate of Ge(IV)-4-nitrocatechol (4-NC) and the cation of 1,4-diphenyl-3-(phenylamino)-1H-1,2,4-triazole (Nitron, Nt) in the liquid-liquid extraction system Ge(IV)-4-NC-Nt-H2O-CHCl3 was studied by spectrophotometry. The optimum extraction-spectrophotometric conditions for the complex formation were established. The validity of Beer's law was checked and some analytical characteristics of the system were calculated. The effect of co-existing ions and reagents on the process of complex formation was investigated. The association process in aqueous phase and the extraction equilibria were studied and quantitatively characterized. The following key constants of the processes were calculated: association constant, distribution constant, extraction constant and recovery factor. The molar ratio of the reagents was determined by independent methods. A reaction scheme and a general formula of the complex were suggested.

Study on the Complex Equilibria of Molybdenum(VI) with 3,5-Dinitrocatechol and Ditetrazolium Salt.

The complex formed between an anionic chelate of Mo(VI)-3,5-dinitrocatechol (3,5-DNC) with the cation of 3,3'-(3,3'-dimethoxy-4,4'-biphenylene)bis(2,5-diphenyl-2H-tetrazolium chloride) (Blue Tetrazolium Chloride, BTC) in the liquid-liquid extraction system Mo(VI)-3,5-DNC-BTC-H2O-CHCl3 was studied. The optimum conditions for the complex formation and extraction of the ion-associated complex were established by spectrophotometry. The molar ratio of the reagents was determined by independent methods. The validity of Beer's law was checked and some analytical characteristics were calculated. The association process in aqueous phase and the extraction equilibria were investigated and quantitatively characterized. The following key constants of the processes were calculated: association constant, distribution constant, extraction constant and recovery factor. Based on this, a reaction scheme, a general formula and a structure of the complex were suggested.

Complex Formation in a Liquid-Liquid Extraction System Containing Co(II), 4-(2-Thiazolylazo)resorcinol and Monotetrazolium Salt.

The ion-associated complex formed between anionic chelate of Co(II)-4-(2-Thiazolylazo)resorcinol (TAR) with the monotetrazolium cation of 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) in the liquid-liquid extraction system Co(II)-TAR-INT-H(2)O-CHCl(3) was studied by the spectrophotometric method. The optimum extraction conditions of Co(II) were found. The extraction equilibria were studied. The equilibrium constants, the recovery factor and some analytical characteristics were calculated. The validity of Beer's law was checked. The molar ratio of the components in the ternary ion-associated complex Co(II)-TAR-INT was determined. The general formula of the complex was suggested. The effect of various foreign ions and reagents on the process of complex formation in the liquid-liquid extraction system was studied.

Ternary ion-association complexes of cobalt with 4-(2-pyridylazo)resorcinol and tetrazolium salts.

The formation of ternary ion-association complexes of Co(II) with 4-(2-pyridylazo)resorcinol (PAR) and tetrazolium salts (TS) - (3-(4,5-dimethylThiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and 3-(2-naphtyl)-2,5-diphenyl-2H-tetrazolium chloride (TV) - were investigated with the aid of the extraction-spectrophotometric method. The optimum conditions for the extraction of Co(II) were found. On the basis of the experimental data and their mathematical treatment the association process in aqueous phase and extraction process was investigated quantitatively. The molar ratios of the components in the associates were determined. The results show that the extracted species could be represented with the general formula (TS)[CoH(PAR)(2)]. The following key constants were calculated: association constant, distribution constant, extraction constant and recovery factor. The validity of Beer's law was checked and some analytical characteristics were calculated.