Histidine In Solution Research Articles

How Does the Concentration of Technetium-99m Radiolabeled Gold Nanoparticles Affect Their In Vivo Biodistribution?

Gold nanoparticles (AuNPs) radiolabeled with therapeutic and diagnostic radioisotopes have been broadly studied as a promising platform for early diagnosis and treatment of many diseases including cancer. Our main goal for this study was the comparison of the biodistribution profiles of four different concentrations of gold nanoconjugates radiolabeled with Technetium-99m (99mTc). More specifically, AuNPs with an average diameter of 2 nm were functionalized with a tridentate thiol ligand. Four different concentrations were radiolabeled with 99mTc-tricarbonyls with high radiolabeling yields (>85%) and were further purified, leading to radiochemical purity of >95%. In vitro stability of the radiolabeled nanoconstructs was examined in cysteine and histidine solutions as well as in human serum, exhibiting robust radiolabeling up to 24 h post-preparation. Moreover, in vitro cytotoxicity studies were carried out in 4T1 murine mammary cancer cells. In vivo tracking of the radiolabeled nanoconjugates at both concentrations was examined in normal mice in order to examine the effect of AuNPs’ concentration on their in vivo kinetics. Our work demonstrates that varying concentrations of radiolabeled AuNPs lead to notably different biodistribution profiles.

Preparation, Characterization, and Radiolabeling of Anti-HER2 scFv With Technetium Tricarbonyl and Stability Studies.

Breast cancer is the most common diagnosed cancer, and the second cause of cancer death among women, worldwide. HER2 overexpression occurred in approximately 15% to 20% of breast cancers. Invasive biopsy method has been used for detection of HER2 overexpression. HER2-targeted imaging via an appropriate radionuclide is a promising method for sensitive and accurate identification of HER2+ primary and metastatic lesions. 99mTc-anti-HER2 scFv can specifically target malignancies and be used for diagnosis of the cancer type and metastasis as well as treatment of breast cancer. We radiolabeled anti-HER2 scFv that was expressed in Escherichia coli and purified through Ni-NTA resin under native condition with 99mTc-tricarbonyl formed from boranocarbonate. HER2-based ELISA, BCA, TLC, and HPLC were used in this study. In the current study, anti-HER2 scFv was lyophilized before radiolabeling. It was found that freeze-drying did not change the binding activity of anti-HER2 scFv to HER2. Results demonstrated direct anti-HER2 scFv radiolabeling by 99mTc-tricarbonyl to hexahistidine sequence (His-tag) without any changes in biological activity and radiochemical purity of around 98%. Stability analysis revealed that 99mTc-anti-HER2 scFv is stable for at least 24 h in PBS buffer, normal saline, human plasma proteins, and histidine solution.

Effect of selected green corrosion inhibitors on SO2 removal during carbon steel corrosion in aqueous solutions of ammonia and histidine

To understand the feasibility of using carbon steel in the flue gas desulfurization process, the corrosion protection of carbon steel was investigated by adding four green corrosion inhibitors (12-aminolauric acid; 4-carboxyphenylboronic acid; 1,2,3-benzotriazole; and L-methionine) to an ammonia solution containing histidine as the SO2 absorbent. The effects of the corrosion inhibitors on the corrosion rates of carbon steel and SO2 absorption performance were investigated. We observed that 1,2,3-benzotriazole was the most effective corrosion inhibitor, reducing the corrosion rate by 73 % and increasing the SO2 absorption loading by 8.3 % compared to other corrosion inhibitors. Scanning electron microscopy/energy dispersive X-ray spectroscopy and X-ray diffraction studies were conducted to understand the corrosion inhibition behavior of 1,2,3-benzotriazole. The formation of the Fen-(SO2-BTA)m complex and its subsequent adsorption on the carbon steel surface blocked active sites and inhibited corrosion. This study demonstrated the feasibility of effectively using carbon steel under harsh environmental conditions such as in desulfurization.

Histidine-Triggered GO Hybrid Hydrogels for Microfluidic 3D Printing.

Graphene oxide (GO) hydrogels have provided tremendous opportunities in designing and fabricating complex constructs for diverse applications, while their 3D printing without photocuring is still a challenging task due to their low viscosity, uncontrollable gelation, and low interfacial tension. Here, we report a histidine-assisted printing strategy to prepare GO hybrid hydrogels through the microfluidic 3D printing technique. We found that the GO additive could significantly hamper the Knoevenagel condensation (KC) reaction between benzaldehyde and cyanoacetate group-functionalized polymers to form a hydrogel, while these GO mixed solutions were rapidly solidified into a hydrogel when histidine was added. This fascinating phenomenon enabled us to prepare low-viscosity GO mixed polymer solutions as printable inks and generate hydrogel microfibers in histidine solutions. The hydrogel fibers could support cell survival and be further constructed into complex 3D structures through microfluidic 3D printing techniques. Moreover, due to the addition of GO, the microfibers exhibited excellent electrical conductivity and could sense the motion changes and convert these stimuli as electrical resistance signals. This strategy adds an option for the design and application of 3D printable aqueous GO inks in many fields.

Treatment of anemia with amino acids. (Sas sard. (Pr. Med. 1933, 12)

The injection of a solution of trypoflavin and histidine in healthy people caused an increase in the number of erythrocytes, an increase in% Hb, mild leukocytosis, a decrease in blood pressure (followed by a slight increase ;, an increase in blood clotting.

Binding of histidine and human serum albumin to dirhodium(II) tetraacetate

Reactions of the anticancer active dirhodium tetraacetate (1), Rh2(AcO)4 (AcO− = CH3COO−), with the amino acid histidine (HHis) and human serum albumin (HSA) were monitored over time and different metal: ligand ratios using UV-vis spectroscopy and/or electro-spray ionization mass spectrometry. Initially, histidine formed 1:1 and 1:2 adducts in aqueous solutions. The crystal structure of Rh2(AcO)4(L-HHis)2·2H2O (2) confirmed the axial coordination of histidine imidazole groups (average Rh-Naxial 2.23 Å). These adducts, however, were found to be unstable in solution over time (24 h). Heating Rh2(AcO)4 –histidine solutions to 40 °C (near body temperature) or 95 °C accelerated the formation of RhII2(AcO)2(His)2 and RhIII(His)2(AcO) complexes. The corresponding pH change from neutral to mildly acid (pH 4–5) indicates deprotonation of histidine NH3+ groups due to coordination to Rh ions, which simultaneously bind to histidine COO− groups, as evidenced by 13C NMR spectroscopy. In the case of HSA with 16 histidine and one cysteine residues, UV-vis spectroscopy indicates that mono- and di-histidine HSA adducts with Rh2(AcO)4 are formed. X-ray absorption spectroscopy showed almost the same Rh-Rh distance (2.41 ± 0.01 Å) for the Rh2(AcO)4 units as in 2, and a contribution from an axial thiol coordination (Rh-Saxial 2.62 ± 0.05 Å). The Rh2(AcO)4 – HSA complex was found to decompose partially (~15%) over 24 h at ambient temperature. The partial decomposition of Rh2(AcO)4 both through coordination to histidine or to human serum albumin, the most abundant protein in blood plasma, is a factor to consider for its efficacy as a potential anticancer agent.

Characteristics and corrosion behavior of Ti–30Nb–5Sn alloys in histidine solution with various NaCl concentrations

Characteristics and corrosion behavior of Ti–30Nb–5Sn alloys in histidine solution with various NaCl concentrations

Effect of the triphenylphosphonium cation on the biological properties of new rhenium and technetium-99m fac-[M(CO)3(NSN)]±-type complexes: Synthesis, structural characterization, in vitro and in vivo studies

Triphenylphosphonium (TPP) cations have been used for the development of tumor or myocardial diagnostic radiopharmaceuticals. In this work, the development of new [99mTc][Tc(CO)3(N,S,N)]+ complexes of the (N,S,N) tridentate chelator benzimidazol-2-yl-methylthioethylamine (L), and its triphenylphosphonium (TPP) cation derivative L-TPP is described. The TPP-moiety was conjugated at the Nτ-benzimidazol position of L. The reaction of the chelators L and L-TPP with a suitable precursor [Re(sol)3(CO)3]+ yielded single products of ReL+ and ReL-TPP2+. The complexes were characterized by spectroscopic methods and furthermore the structure of ReL was elucidated by X-ray crystallography. The respective 99mTc-radiotracers were synthesized in high yield, their lipophilicity was measured and both exhibited high stability in cysteine, histidine solutions as well as in rat plasma. The in vitro cell studies in human erythroleukemia K-562 and glioblastoma U-87MG tumor cells showed that the tracer 99mTcL+ exhibited significantly higher cellular uptake, while 99mTcL-TPP2+ exhibited significantly higher mitochondrial accumulation. The tracers 99mTcL+ and 99mTcL-TPP2+ exhibited fast blood elimination and excretion via the hepatobiliary and the renal routes after intravenous administration in healthy mice. Tracer 99mTcL+ exhibited higher myocardial uptake and renal excretion, while 99mTcL-TPP2+ exhibited primarily hepatobiliary excretion. These data confirm the high mitochondrial accumulation of 99mTcL-TPP2+ in vitro and show its potential as a candidate for tumor imaging.

Synthesis and antimicrobial evaluation of Histidine Cinnamaldehyde Schiff base containing structural feature of 1, 3, 4-thiadiazole heterocyclic moiety

Reaction of aqueous solution of amino acid Histidine with ethanolic solution Cinnamaldehyde to synthesize the desired Schiff base. Then, the derivative of 1, 3, 4-thiadiazole ring have been synthesized by reaction of the imine derivative with Thiosemicarbazide in presence of POCL3.
 The entire intermediate and final compound characterized and identified by elemental microanalysis as melting point, FT-IR spectra, 1H-NMR spectroscopy. Agar Well Diffusion method evaluated the antimicrobial activity on gram positive bacteria such as Staphylococcus aureus and Streptococcus pneumonia and gram-negative bacteria such as E coli & Acinetobacter species and also antifungal activity had been studied on one type of fungi (candida albicans).

Synthesis and antimicrobial evaluation of Histidine Cinnamaldehyde Schiff base containing structural feature of 1, 3, 4-thiadiazole heterocyclic moiety

Reaction of aqueous solution of amino acid Histidine with ethanolic solution Cinnamaldehyde to synthesize the desired Schiff base. Then, the derivative of 1, 3, 4-thiadiazole ring have been synthesized by reaction of the imine derivative with Thiosemicarbazide in presence of POCL3. The entire intermediate and final compound characterized and identified by elemental microanalysis as melting point, FT-IR spectra, 1H-NMR spectroscopy. Agar Well Diffusion method evaluated the antimicrobial activity on gram positive bacteria such as Staphylococcus aureus and Streptococcus pneumonia and gram-negative bacteria such as E coli & Acinetobacter species and also antifungal activity had been studied on one type of fungi (candida albicans).

Thermodynamics of Mixed Ligand Complex Formation of Copper(II) and Nickel Ions with Glycine and Histidine in Solution

Mixed ligand complexes of copper(II) and nickel(II) with glycine (Gly) and histidine (His) have been studied in aqueous solution using calorimetric, potentiometric and spectrophotometric data at 298.15 K and the ionic strength of I = 0.5 mol·L–1 (KNO3). The thermodynamic parameters of formation of various mixed complexes have been determined. The probable coordination modes of amino acid residues in mixed ligand complexes is discussed.

Effects of in ovo injection of L-histidine on hatch performance and post-hatch development in domestic pigeons (Columba livia)

The objective of this study was to evaluate the effects of in ovo injection of histidine on hatch performance and post-hatch development by determining hatchability, hatching time, BW gain, carcass traits, and intestinal morphology in domestic pigeons (Columba livia). A completely randomized design (n = 3) with a L-histidine injection treatment (His group, 0.55mg histidine dissolved in 200 μL 0.75% saline as 1% Conc compared to total histidine in the egg), a 0.75% saline injection treatment (SC group), and non-injection treatment (NC group) was used. Six squabs from each treatment were randomly sampled at day of hatch (DOH), day 7 (D7), and day 14 (D14) post hatch, respectively. Results showed that in ovo injection of histidine solution increased (P < 0.01) the hatchability in comparison with that of other groups. The hatching time of His group was earlier (P = 0.05) than that of the NC group. In ovo injection of histidine had no influence (P > 0.05) on BW gain and carcass traits, but had a significant effect on the organ index of pigeons. The index of pancreas on DOH, the indices of leg, gizzard, proventriculus, small intestine, and pancreas on D7, and the index of head on D14 were significantly increased (P < 0.05) by injection of histidine. Moreover, in ovo injection of histidine had significant effects on the weight indices of different intestinal segments and jejunal morphology in squabs. Ileum weight index on D7 from His group was significantly higher (P < 0.05) than that of other groups. Compared with the NC group, the jejunal crypt depth on DOH and D7 of His group decreased (P < 0.05), while jejunal villus area and villus crypt ratio on D7 of His group increased (P < 0.05). The results of this study indicate that in ovo injection of histidine may have beneficial effects on squabs' hatchability, intestinal development but have negligible effects on their growth performance during early post-hatch period.

New ternary complexes of zinc ions with glycine and histidine in solution

Mixed-ligand complexes of zinc with glycine (Gly) and histidine (His) have been studied in an aqueous solution at 298.15 K and I = 0.5 (KNO3) using calorimetric and pH-metric data. The thermodynamic parameters of formation of various mixed complexes have been determined. The probable coordination modes of amino acid residues in mixed-ligand complexes have been discussed.

Selective turn-off sensing of picric acid and p-nitrophenol using fluorescent histidine

In this communication, a bluish-green fluorescent histidine was synthesized by direct heating of an aqueous solution of histidine at 70°C for 48 h and characterized by various techniques like FT-IR, UV–Vis,fluorescence, FESEM and DLS. Then, the sensing ability of the fluorescent histidine was applied towards nitroaromatic compounds in pure aqueous medium. The fluorescence of fluorescent histidine at 450 nm was selectively quenched upon addition of picric acid (PA) and para-nitrophenol (PNP) through energy transfer mechanism among the other tested nitroaromatic compounds. With the proposed sensor, the PA and PNP can be estimated down to 27.16 × 10−7 M and 35.26 × 10−7M, respectively without any interference from other tested nitroaromatic compounds. Finally, the practical utility of the developed sensor was applied for the detection of PA and PNP in real environmental samples.

Ligands representing important functional groups of natural organic matter facilitate Fe redox transformations and resulting binding environments

Abstract Functional groups in natural organic matter have the potential to interact with and stabilize iron (Fe) redox species (ferric, ferrous) through complexation reactions. In this study, iron complexes with cysteine, arginine and histidine are used to investigate the extent to which specific functional groups present in these amino acids might hinder the oxidation of Fe2+ or promote the reduction of Fe3+. Iron complexes are synthesized by addition of ferrous or ferric salts to cysteine, arginine and histidine solutions at pH 7. The Fe-amino acid complexes are analysed using X-ray Absorption Spectroscopy (XAS), theoretical CTM4XAS (Charge Transfer Multiplet for XAS) calculations, and vibrational spectroscopy (FTIR and Raman). In addition, oxidation of the amino acids is determined by linear sweep voltammetry and chemical equilibrium modeling is used to predict the speciation of Fe in complexes with the amino acids. It is observed the extent of Fe redox transformation is affected by the electron donating capability of the ligand with which Fe reacts. In particular, the extent of Fe3+ reduction is related to the oxidation of the ligand with 80, 14 and 0% Fe3+ reduction by cysteine, arginine and histidine, respectively. Conversely, Fe2+ is preserved by cysteine (80%) > arginine (77%) > histidine (62%). The chemical forms of Fe in these mixed Fe oxidation-state systems include Fe-organic complexes and Fe precipitates. XAS and vibrational spectroscopy indicate thiol-S and amino-N bind Fe in complexes with cysteine. While amino-N and guanidyl-N functional groups of arginine bind Fe, carboxylate-O binding and the formation of Fe precipitates are only observed when Fe3+ is the predominant redox species. Whereas Fe precipitates seem to prevail in Fe(III)-histidine, distinct organic (Fe O/N C) and mineral (Fe O Fe) or mixed organic-mineral (Fe(O/N C)x(O Fe)y) coordination environments occur in Fe(II)-histidine with ∼60% Fe2+; in either case, Fe N(imidazole) binding is not evident. The ligand atoms to which Fe binds and the inherent reduction capacity of the ligand appear to mediate Fe redox transformations. The proportion of ferric iron (Fe3+) seems to determine whether a precipitate forms. Consistent with spectroscopic data, chemical equilibrium modeling using experimental solution conditions and fractional Fe2+ and Fe3+ concentrations obtained from CTM4XAS predict the formation of Fe(II)- and Fe(III)-amino acid complexes and hydrolyzed Fe species; these calculations however also predict the formation of Fe oxide precipitates in all Fe complexes. The results presented in this study help to explain the co-occurrence of Fe2+ and Fe3+ in natural environments where organic matter is present. They also highlight the role specific organic functional groups play on the formation and stabilization of Fe(II, III)-organic complexes and precipitates, and thus on the Fe redox cycle which affects Fe bioavailability and mobility in terrestrial and subsurface environments.

Photo-Fenton approach for the determination of organic nitrogen in rainwater

The importance of taking the organic forms of nitrogen (ON) into account when estimating atmospheric nitrogen deposition has been known for a long time. However, there is still only a modest amount of data on organic nitrogen in rainwater worldwide, largely due to the difficulties and uncertainties imposed by the available analytical methods. This work offers a simple, low cost, and reliable method for the determination of ON in rainwater, based on the photo-Fenton process under UV irradiation. The recovery of ON was determined using individual solutions of urea, serine, glycine, and histidine, as well as a mixture of all these compounds plus arginine. Close to 100% organic nitrogen recoveries were obtained for solutions containing 50 μmol N L−1, using addition of 50 μmol L−1 Fe2+ and 2.0 mmol L−1 H2O2, with adjustment of the pH to ∼2.5 and irradiation for 90 min. The average reagent blank was <2.0 μmol N L−1. The homemade reactor employed a 400 W high pressure mercury lamp, from which the external bulb had been manually removed. The reactor ventilation was controlled in order to maintain the temperature at ∼85 °C. The precision of the method ranged from 1.3 to 5.7%, based on ON recovery. Rainwater collected on an event basis in Ribeirão Preto (São Paulo State, Brazil) presented ON concentrations from 4.1 to 34.3 μmol L−1 (n = 18), corresponding to 13–45% of the total nitrogen, with an average contribution of 33%. Precision of ≤7.0% was obtained for the analysis of ON in rainwater.

A Comparison of Pancreatic Islet Purification using Iodixanol with University of Wisconsin Solution and with Na-Lactobionate and Histidine Solution.

Purification of pancreatic islets is an important step in islet isolation for islet transplantation. In this study, to investigate how a solution composed mainly of Na-lactobionate and histidine (HL) influences the purification of islets, iodixanol was added to a purified solution for porcine islet isolation. A solution (IU) made by adding iodixanol to University of Wisconsin solution and a solution (IHL) made by adding iodixanol to HL solution were used to evaluate the islet isolation performance. We noted no significant differences between the two purification methods with regard to the islet yield, survival rate or purity, score, or stimulation index. These results show that IHL solution is as useful as IU solution for islet purification.

Donnan-Potential Sensors Based on Zirconia-Modified Nafion Membranes Treated under Different Conditions for the Determination of Amino Acids with Several Nitrogen-Containing Groups

The effect of heat treatment at varying relative humidity and mechanical deformation on the properties of Nafion perfluorosulfonic cation-exchange membranes and Nafion-based hybrid materials containing hydrated zirconia nanoparticles has been studied. It has been shown that the treatment of the materials makes it possible to change their water uptake, ionic conductivity, and diffusion permeability over wide ranges. Variations in the water uptake and intrapore space volume of the membranes provided by their treatment and modification have led to a decrease in the sensitivity of DP-sensors (the analytical signal is the Donnan potential) to interfering hydroxonium cations in arginine and histidine solutions in 1.5−5 times. The material samples providing a high accuracy of determination of amino acid ions in a concentration range from 1.0 × 10–4 to 1.0 × 10–1 mol/L at pH < 7 have been selected.

Thermodynamics of Ternary Complex Formation of Copper(II) and Nickel Iminodiacetates with Histidine in Solution

Calorimetric, potentiometric and spectrophotometric studies on the mixed–ligand complexes of copper(II) with nickel iminodiacetates (Ida) and histidine (His) have been carried out in aqueous solution at 298.15 K and ionic strength I = 0.5 mol·dm−3 (KNO3). The thermodynamic parameters of formation of various mixed complexes have been determined. The probable coordination modes of the complexone and histidine residues in the mixed ligand complexes are discussed.

Gasification characteristics of histidine and 4-methylimidazole under supercritical water conditions

In this study, gasification characteristics of histidine and 4-methylimidazole were investigated for the first time. A tubular flow reactor was employed, and experiments were conducted in the temperature range of 500–650 °C, at a fixed pressure of 25 MPa, with residence times of 86–119 s, and with 1.0 wt% aqueous solutions of histidine and 4-methylimidazole. The gaseous products were identified and quantified by gas chromatography (GC), and the aqueous phase was analyzed for total organic carbon (TOC). The gasification characteristics were compared with those of glycine and alanine, which represented the standard amino acid structure. The result showed that the carbon gasification efficiencies of both histidine and 4-methylimidazole increased with increasing reaction temperature. The gasification rate of 4-methylimidazole followed first-order kinetics and was explained well by the Arrhenius equation. The gasification rate for histidine could be predicted by the weighted summation of the adjusted gasification rates of glycine and 4-methylimidazole.