Influence Of Human Serum Albumin Research Articles

Influence of HSA on micellization of NLSS and BC: An experimental-theoretical approach of its binding characteristics

Blood albumins play a very significant role in several biological operations and act as carriers for the transportation and circulation of various endogenous as well as exogenous materials. Experimental as well as computational studies have been carried out in understanding the major binding properties of the system. This investigation explains the interactions of Human serum albumin (HSA) with N-Lauroyl sarcosine sodium salt (NLSS) and benzethonium chloride (BC), which has been explored by means of conductometric, spectroscopic as well as computational studies. Phenomenon of micellization is hindered in several concentrations of protein (HSA) as well as by temperature. Binding ability of HSA with NLSS and BC has been obtained through UV–visible and fluorescence studies. Computational study revealed the presence of seven binding pockets in HSA, out of which the most stable binding pockets for NLSS and BC includes pocket1 and pocket2.

Reactions of radicals with PERK kinase inhibitor and its analogue under oxidative and reductive stress conditions. Pulse radiolysis study

The scavenging of primary free radicals generated during radiolysis of water (eaq−,•OH, •H) and CO2•‒ (reducing radical) or N3• (oxidizing radical) by PERK inhibitor, AMD (3-acetyl-6-methylheptane-2,4-dione) and APD (3-acetyl-2,4-pentanedione) has been studied with details. AMD is a low molecular weight inhibitor of the PERK-dependent antiproliferative signaling pathway and constitutes the foundation of an innovative therapeutic strategy in the treatment of cancer diseases. The applied compounds exist in the three different forms depending on pH of aqueous solution: ketone, enol and enolate form. The effect of pH on the absorption spectra of AMD and APD has been studied and the value of pKa for the keto – enol equilibrium (conversion of the ketone to enol) and pKa for the enol – enolate form were calculated. Redox processes studied by pulse radiolysis method were more effective at neutral or alkaline pH than in an acidic solution. The influence of human serum albumin (HSA) on the oxidation and reduction process of examined compounds was studied. The kinetics of radicals reaction with tested compounds has been compared for neat buffer solution and systems containing HSA. The results indicate competitive electron scavenging by studied scavengers and protein.

Competitive Binding of Tolmetin to β-Cyclodextrin and Human Serum Albumin: 1H NMR and Fluorescence Spectroscopy Studies

The host–guest interaction of tolmetin (TOL) with β-cyclodextrin (β-CD) and the influence of human serum albumin (HSA) on the formation of the inclusion complex were studied by 1D and 2D NMR spectroscopy. The TOL/β-CD inclusion complex formed at a molar ratio of 1:1 with a binding constant value of 2164.5 L·mol−1. Data analysis showed that the addition of 10 μmol·L−1 of HSA weakened the strength of TOL binding to β-CD (Ka = 1493 L·mol−1). The interaction of TOL with HSA in the absence and presence of β-CD was studied by analyzing the fluorescence quenching data. The Stern–Volmer quenching constants and the binding constants are found to be smaller in the presence of β-CD, suggesting that β-CD hinders the strong interaction of TOL with HSA by complex formation. Additionally, the presence of β-CD does not induce conformational and microenvironmental changes on HSA.

Influence of human serum albumin on the bile acid-mediated inhibition of liver microsomal type 1 11β-hydroxysteroid dehydrogenase.

The influence of human serum albumin (HSA) on the bile acid-mediated inhibition of liver microsomal type 1 11β-hydroxysteroid dehydrogenase (11β-HSD1) was studied in vitro. A rat liver microsomal fraction was prepared, and the 11β-HSD1 enzyme activity in the presence of various concentrations of bile acids and HSA was determined using hydrocortisone as the substrate. The products of the reaction were extracted and analyzed using high-performance liquid chromatography. The magnitude of the inhibition decreased with the addition of HSA in a dose-dependent manner. Four percent human albumin decreased the inhibitory effects of 100 μM chenodeoxycholic acid and lithocholic acid from 89.9 ± 5.6 to 54.5 ± 6.1% and from 83.8 ± 4.8 to 20.8 ± 4.2%, respectively. In contrast, ursodeoxycholic acid and deoxycholic acid showed no inhibitory effect on the enzyme activity in the presence of 4% human serum albumin, and the addition of 1% γ-globulin to the assay mixture in the presence of bile acids did not affect the enzyme activity. Our in vitro study showed that the addition of HSA ameliorated the inhibition of 11β-HSD1 and that the magnitude of the change is dependent on the species of bile acid, presumably based on the numbers of hydroxyl groups. These results suggest that HSA seems to protect the bile acid-mediated inhibition of 11β-HSD1 in the healthy subject. On the other hand, in the patients with obstructive biliary diseases, not only elevated serum bile acid but also the accompanying hypoalbuminemia is important to evaluate the pathophysiology of the bile acid-mediated inhibition of 11β-HSD1 of the disease.

A study on human serum albumin influence on glycation of fibrinogen

Although in vivo glycation proceeds in complex mixture of proteins, previous studies did not take in consideration the influence of protein–protein interaction on Maillard reaction. The aim of our study was to test the influence of human serum albumin (HSA) on glycation of fibrinogen. The isotopic labeling using [13C6] glucose combined with LC-MS were applied as tool for identification possible glycation sites in fibrinogen and for evaluation the effect of HSA on the glycation level of selected amino acids in fibrinogen.The obtained data indicate that the addition of HSA protects the fibrinogen from glycation. The level of glycation in presence of HSA is reduced by 30–60% and depends on the location of glycated residue in sequence of protein.

Chimmitecan, a Novel 9-Substituted Camptothecin, with Improved Anticancer Pharmacologic Profiles In vitro and In vivo

This study aimed to evaluate antitumor activities and pharmacologic profiles of chimmitecan, a novel 9-small-alkyl-substituted lipophilic camptothecin, in comparison with irinotecan (CPT-11) and topotecan. The in vitro cytotoxities of chimmitecan in human tumor cell lines and multidrug resistance (MDR) cells were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and sulforhodamin B assays. DNA relaxation, cleavage assays, and cellular band depletion assay were combined to delineate its effects on topoisomerase I. DNA damage, cell cycle arrest, and apoptosis were assessed using comet assay, flow cytometry, and DNA ladder analysis, respectively. The in vivo antitumor activities were measured in nude mice bearing human tumor xenografts. Chimmitecan displayed more potent cytotoxicity than SN38 and topotecan. Neither a cross-resistance to chimmitecan in MDR cells nor an influence of human serum albumin in its cytotoxity was observed. Chimmitecan exhibited comparable effects on topoisomerase I compared with the reference drugs, including inhibiting topoisomerase I catalytic activity and trapping and stabilizing covalent topoisomerase I-DNA complexes. Furthermore, nanomolar levels of chimmitecan caused impressive DNA damage, G(2)-M phase arrest, and apoptosis in human leukemia HL60 cells. I.v. administration of chimmitecan inhibited the growth of HCT-116, MDA-MB-435, BEL-7402, and A549 human carcinoma xenografts in nude mice, with greater potency than CPT-11 against the latter two tumors models. Chimmitecan presented potent efficacy in A549 tumor model when given orally. Chimmitecan is a potent inhibitor of topoisomerase I and displays outstanding activity in vitro and in vivo. The substitution at the 9-position benefits chimmitecan a salient anti-MDR activity, stability in human serum albumin, improved solubility, and oral availability, which might favorably promise its therapeutic potential in clinical settings.

The Influence of Human Serum Albumin on The Photogeneration of Singlet Oxygen by meso-Tetra(4-Sulfonatophenyl)Porphyrin. An Infrared Phosphorescence Study

meso-Tetra(4-sulfonatophenyl)porphyrin (TPPS4) is a water soluble photosensitizer, which is currently clinically tested as a PDT drug. In our contribution, we present IR spectral- and time-resolved phosphorescence data reflecting the influence of human serum albumin (HSA) on singlet oxygen photogeneration by TPPS4. IR emission of TPPS4 was studied in samples containing various concentrations of HSA in phosphate buffer. The observed changes in spectral and temporal behaviour of TPPS4 and singlet oxygen phosphorescence caused by the addition of HSA are equivalent to the effect of nitrogen purging of HSA-free solutions of TPPS4. The main feature induced by addition of HSA appears to be the occurrence of a long-lived (tens of microseconds) photosensitizer phosphorescence at 900 nm besides ordinary short-lived (approximately 2 micros) one at 820 nm. It is accompanied by presence of a long-lived component of singlet oxygen emission with lifetime roughly corresponding to that of the long photosensitizer phosphorescence component. Moreover, the quantum yield of singlet oxygen phosphorescence decreases with increasing HSA concentration, while total quantum yield of TPPS4 phosphorescence rises. These facts are explained by a shielding effect of HSA on bound molecules of TPPS4 against quenching by oxygen which is analogous to oxygen removal by nitrogen purging.

Influence of HSA on the properties of OA/OAM monolayers and the growth of calcium oxalate

The properties of octadecanoic acid/octadecylamine (OA/OAM) monolayers and crystal growth of calcium oxalate induced by the monolayers on subphases containing supersaturated calcium oxalate (CaC 2O 4) solution and different concentrations of human serum albumin (HSA) (0.00, 0.02, 0.08, and 0.10 wt.%) were studied in this paper. The results demonstrated that HSA could be adsorbed by OA/OAM monolayers, which was confirmed by Fourier transform infrared (FTIR) spectra, UV-Vis absorption spectra, respectively. The adsorption of different concentrations of HSA changed the properties of the monolayers, which resulted in the appearance of different crystal morphologies of CaC 2O 4 such as calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD), calcium oxalate trihydrate (COT). HSA could promote the growth of COT crystals. COM only formed on the CaC 2O 4 supersaturated solution containing 0.08% HSA. The formation process of COM was tracked in kinetic experiments by Scanning electron microscopy (SEM), transformation from COT into COM could be seen, which would take about 480 h. In order to prohibit the transformation, 1,2-bis( O-aminophenoxy)ethane- N, N, N, N-tetracetic acid (BAPTA) was synthesized and added to the above subphase, expected results were obtained.

Induced crystal growth of calcium oxalate monohydrate at hydroxyapatite surfaces. The influence of human serum albumin, citrate, and magnesium

Induced crystal growth of calcium oxalate monohydrate at hydroxyapatite surfaces. The influence of human serum albumin, citrate, and magnesium

Influence of Serum Albumins on Decomposition Rates of Para- Substituted 1-phenyl-3-methyltriazenes and 5-(3-methyl-1-triazeno)imidazole-4-carboxamide in Near Physiological Conditions

The influence of human serum albumin on the decomposition rates of some arylmonomethyltriazenes in buffered aqueous solution was investigated. From the experimental data, a model for the triazene-albumin interaction was derived, and the thermodynamic parameters were systematically calculated by two independent methods. The results show marked dependence of the energetics of binding on the substituent in the triazene aromatic ring. For most of the triazenes studied, the binding with albumin was mainly enthalpy driven. Measurements also were performed using bovine and murine serum albumins.

Influence of sex hormone binding globulin and serum albumin on the conversion of androstenedione to testosterone by human erythrocytes.

The influence of human serum albumin and sex hormone binding globulin (SHBG) on the enzymic conversion of androstenedione to testosterone in human erythrocytes was investigated in vitro. Total plasma and albumin delayed the conversion rate of androstenedione, while SHBG increased it markedly. The effect of SHBG was largely abolished by heating to 60 degrees C for 1 h and by saturating its binding sites by DHT. The effect of both proteins was found to be related to their concentration. It appears that the binding sites of albumin provide a mechanism for retarding androstenedione uptake by the erythrocytes and that the high binding affinity of SHBG for testosterone facilitates the diffusion of this steroid out of the cell and thus, displaces the chemical equilibrium within the cell.

Interaction of human serum albumin with anticancer agents in vitro

The influence of human serum albumin (HA) on the biological effects of 13 chemotherapeutic agents was studied in vitro in the human leukaemia cell line MOLT-3. On the basis of changes in biological activity influenced by HA, these drugs may be divided into three types. Type I agents include cis-diamminedichloroplatinum (II), 4'-(9-acridinylamino)methanesulphon-m-anisidide, neocarzinostatin, nitrogen mustard, adriamycin, daunorubicin and mitomycin C--drugs whose biological activities are reduced in the presence of HA. The biological activities of Type II drugs (cytosine arabinoside, fluorouracil and actinomycin D) are not influenced by HA. The biological activities of Type III drugs (bleomycin, vincristine and vinblastine) are increased in the presence of HA. These results indicate that serum HA interferes in vitro with certain anticancer agents in terms of biological activity and, probably, clinical effectiveness. HA-drug interaction may be a major factor governing the pharmacology of Type I anticancer agents in man.

Studies concerning the function of the complex subcommissural organ-liquor fibre: The binding ability of the liquor fibre to pyrocatechin derivatives and its functional aspects

(1) The subcommissural organ (SCO) and its secretion, condensed in the cerebrospinal fluid (CSF) to the Liquor fibre (LF, = Reissner's fibre), form a complex with still doubtful function. Recent results favour the concept of a detoxicating function of the SCO secretion in the CSF (binding hypothesis) 17,26,27,52. This study amplifies these results on the binding properties of LF to norepinephrine (NE) and epinephrine (E). The physiological significance of these properties is discussed. (2) After incubation of isolated bovine LF in solutions containing [ 3H]alanine or [ 3H]tyrosine and subsequent repeated washing, no radioactivity was detected by liquid scintillation counting in LF specimens. Hence, these substances cannot be firmly bound by bovine LF at the concentrations used. (3) When LF was incubated in solutions containing [ 14C]NE and/or [ 131I]-human serum albumin (HSA) in different concentration ratios and measured as above, no influence of HSA on the amount of amine bound to LF, nor of NE on the HSA amount was observed. The amount of HSA remaining bound to LF after washing was always very small, whereas that of NE exceeded its concentration in the surrounding medium. (4) Protein fractions of bovine CSF, incubated in solutions of [ 14C]NE, and separated by disc electrophoresis, contained no radioactivity. Hence we suggest that, in comparison with these proteins (and with HSA, see above), the binding properties described are also LF specific. (5) Catecholamines, capable of disturbing the activity of the nervous system, were found in the CSF in variable amounts ( e.g. see refs. 11, 13, 14, 44). Whether the binding properties of the Liquor fibre have some physiological significance is therefore discussed. The most favourable conditions for such an assumption seem to exist, for various reasons, in the central canal of the spinal cord.

Adsorption of insulin to infusion bottles and tubing.

The adsorption of clinically used quantities of insulin to infusion systems was studied. Isotonic saline solutions containing tracer quantities of beef insulin-I-131, with or without varying amounts of nonradioiodinated (carrier) regular beef insulin, were added to bottles of 500 ml. infusion sets. The solutions were then allowed to flow out into collection beakers. Adsorption was assessed by measuring the decrease of radioactivity in the solutions and/or recovery from the bottles by 30 per cent potassium hydroxide (KOH). The influence of human serum albumin (HSA) on adsorption was evaluated by repeating the experiments after HSA was added to the infusion fluid. Adsorption of insulin-I-131 to both bottles and tubing was considerable, especially at low concentrations of carrier insulin. HSA effectively reduced the adsorption to clinically insignificant amounts.