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Abstract  

The importance of angiogenesis in tumor growth and metastasis has led to develop new imaging tracers to understand angiogenic vasculature. Based on the previous study, we further focused on the tumor molecular imaging application of the novel peptide Arginine-Arginine-Leucine (Tyr-Cys-Gly-Gly-Arg-Arg-Leu-Gly-Gly-Cys, tRRL) in this study. The cytotoxicity of raioiodinated tRRL (131I-tRRL) in HepG2 cells was assessed by tested cell viability using kit. tRRL was conjugated with fluorescein FITC to observe its binding with tumor cells and human aortic endothelial cells (HAEC) in vitro. Whole body SPECT imaging of varied tumors xenograftes was performed after intravenous injection of 131I-tRRL for 24 h in BALB/c nude mice. Compared with negative control PBS, small peptide tRRL was of non-cytotoxicity. 131I-tRRL could lead to significant cytotoxicity on HepG2 cells when the radioactivity was greater than 370 kBq. In vitro binding experiment and cellular uptake results revealed that tRRL could adhere to tumor cells besides tumor derived endothelial cells. In vivo SPECT imaging, 131I-tRRL mainly accumulated in various tumor tissues, including melanoma, liver cancer and lung cancer bearing mice. In breast cancer xenografte imaging, the tumor has no significant radionuclide accumulation at 24 h after injected of 131I-tRRL. Radioiodinated tRRL offers a noninvasive nuclear imaging method for functional molecular imaging of tumors, and may be a promising candidate carrier for tumor targeted therapy.

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Abstract  

This work reports the synthesis, radiolabeling and preliminary biodistribution results in tumor-bearing mice of [99mTc(CO)3(IDA–PEG3–CB)]. The novel chlorambucil derivative was successfully synthesized by conjugation of iminodiacetic acid (IDA) to chlorambucil via a pegylated linker. The ligand could be labeled by [99mTc(CO)3]+ core in high yield to get [99mTc(CO)3(IDA–PEG3–CB)], which was very hydrophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that [99mTc(CO)3(IDA–PEG3–CB)] accumulated in the tumor with favorable uptake and retention. The good accumulation in tumor tissue with high tumor/muscle ratios warrants further research to improve tumor targeting efficacy and pharmacokinetic profile of radiolabeled chlorambucil derivative by structural modification.

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Application of microcalorimetry and principal component analysis

Antibacterial evaluation of Benzoinum and Styrax on Staphylococcus aureus growth

Journal of Thermal Analysis and Calorimetry
Authors:
Jian Wang
,
Danhong Cheng
,
Nan Zeng
,
Houlin Xia
,
Yong Fu
,
Dan Yan
,
Yanling Zhao
, and
Xiaohe Xiao

Abstract  

A useful microcalorimetric technique based on the bacterial heat production was applied to evaluate the antibacterial effects of Benzoinum and Styrax on the growth of Staphylococcus aureus (S. aureus). The thermogenic power-time curves of S. aureus growth in the presence of the two drugs were determined by a thermal activity monitor (TAM) air isothermal microcalorimeter, ampoule mode, at 310 K. Some quantitative metabolic parameters, such as growth rate constant k, the heat-flow power P, the appearance time for the heat power t, and the heat production Q were obtained from these curves. By analyzing these curves and some quantitative parameters using principal component analysis (PCA), the antibacterial effects of Benzoinum and Styrax on S. aureus growth were accurately evaluated from the change of the two main parameters, the heat-flow power for the second peaks P 2nd and total heat production Q t: the antibacterial effects of the two drugs at concentrations of 0–125 mg mL−1 were both enhanced with increasing the concentration, and Benzoinum with IC50 of 132.2 mg mL−1 had stronger antibacterial effect than Styrax with IC50 of 179.8 mg mL−1. This study provides some useful references for the application of Benzoinum and Styra as potential antibacterial agents. Microcalorimetry is a powerful analytical tool for the characterization of the microbial growth progress and the evaluation of the drugs’ efficiency.

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Xinjiang rice wheat ( Triticum petropavlovskyi Udacz. et Migush, 2n=6x=42, AABBDD) is one of the endemic Chinese wheats, only distributing in Xinjiang and Xizang (Tibet), China. A novel high-molecular-weight (HMW) glutenin subunit gene 1Dx2.1 was isolated and characterized from Xinjiang rice wheat accession Daomai2. The complete open reading frame (ORF) of 1Dx2.1 is 2508 bp, encoding 836 amino acids. The primary structure of 1Dx2.1 consists of three distinct domains, a non-repetitive N-terminal domain with 89 residues, a non-repetitive C-terminal domain with 42 residues and a large central repetitive domain with 684 residues. In the N-terminal of 1Dx2.1, there is an R (arginine) at position 75, whereas there is a Q (glutamine) in other known x-type subunits. Four cysteine residues are observed in 1Dx2.1 with three in the N-terminal region and one in the C-terminal region. The number and distribution of cysteines in 1Dx2.1 are identical to those in x-type subunits except for 1Dx5, which possesses an extra cysteine residue. Differences between the repetitive domain of 1Dx2.1 and those of known HMW subunits resulted from substitutions, insertions or/and deletions involving single or more amino acid residues. The phylogenetic tree, which was constructed on the basis of amino acid sequences, and indicated that 1Dx2.1 was highly related to 1Dx2.1 t , then to 1Dx2 and 1Dx5.

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10-Methoxycamptothecin (MCPT) and 10-hydroxycamptothecin (HCPT) are the indole alkaloids isolated from a Chinese tree, Camptotheca acuminata, and have a wide spectrum of anticancer activity in vitro and in vivo mainly through inhibitory effects on topoisomerase I. HCPT is a major metabolite of MCPT in rats; the pharmacokinetic analysis and tissue distribution of MCPT and HCPT in rats have also been determined after i.v. injection of MCPT, but the excretion of MCPT and its metabolite HCPT has not been assessed up to now. In the present study, the excretion study of MCPT and its metabolite HCPT in rat bile, feces, and urine after i.v. administration of MCPT (5 mg kg−1) was performed by high-performance liquid chromatography (HPLC) method coupled with a fluorescence detector. The results showed that MCPT mainly biotransformed to HCPT and excreted in the form of HCPT and MCPT in bile, urine, and feces after i.v. administration of MCPT. It was excreted about 1.24 ± 0.07% as MCPT and 5.49 ± 0.40% as HCPT in bile within 6 h after i.v. administration. The cumulative excretions of MCPT and HCPT were mainly within 24 h after i.v. administration, which were 0.41 ± 0.10% and 7.66 ± 1.43% of the dosage in urine and about 0.16 ± 0.04% and 20.30 ± 3.35% of the dosage in feces. The total excretion of MCPT in urine, bile, and feces was 1.81 ± 0.09% in the form of original MCPT and 33.45 ± 1.57% detected as the metabolite HCPT in urine, bile, and feces, suggesting that MCPT might undergo other biotransformation.

Open access

Exploring antibiotic resistant mechanism by microcalorimetry

Determination of thermokinetic parameters of metallo-β-lactamase L1 catalyzing penicillin G hydrolysis

Journal of Thermal Analysis and Calorimetry
Authors:
Hui-Zhou Gao
,
Qi Yang
,
Xiao-Yan Yan
,
Zhu-Jun Wang
,
Ji-Li Feng
,
Xia Yang
,
Sheng-Li Gao
,
Lei Feng
,
Xu Cheng
,
Chao Jia
, and
Ke-Wu Yang

Abstract

In an effort to probe the reaction of antibiotic hydrolysis catalyzed by B3 metallo-β-lactamase (MβL), the thermodynamic parameters of penicillin G hydrolysis catalyzed by MβL L1 from Stenotrophomonas maltophilia were determined by microcalorimetric method. The values of activation free energy ΔG θ are 88.26, 89.44, 90.49, and 91.57 kJ mol−1 at 293.15, 298.15, 303.15, and 308.15 K, respectively, activation enthalpy ΔH θ is 24.02 kJ mol−1, activation entropy ΔS θ is −219.2511 J mol−1 K−1, apparent activation energy E is 26.5183 kJ mol−1, and the reaction order is 1.0. The thermodynamic parameters reveal that the penicillin G hydrolysis catalyzed by MβL L1 is an exothermic and spontaneous reaction.

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Abstract

The antibacterial effect of Curcumin on Staphylococcus aureus growth was evaluated by microcalorimetry. The heat flow power–time curves and nine quantitative parameters of the S. aureus growth were applied to investigate the inhibitory effect with Curcumin. By analyzing these curves and some quantitative parameters using multivariate analytical methods, similarity analysis and principal component analysis, the antibacterial activity of Curcumin on S. aureus could be accurately evaluated from the change of the two main parameters, the second exponential growth rate constant k 2 and the maximum heat flow power P m 2. The main two thermal parameters played more important role in the evaluation: at low concentration (0–10.5 μg mL−1), Curcumin hardly influence the growth of S. aureus, while at high concentration (10.5–43.4 μg mL−1) it could notably inhibit the growth. All these illustrated that the antibacterial activity of Curcumin on S. aureus was enhanced with the increase of the concentration of this compound. This study might provide an useful method and idea accurately evaluate the antibacterial effects of Curcumin, which provides some useful methods for evaluate the nature antibacterial agents.

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Abstract

A rapid and sensitive High-Performance Liquid Chromatography-tandem Mass Spectrometry (HPLC/MS/MS) method for determining apremilast in beagle dog plasma and urine samples was developed and validated using clopidogrel as the internal standard (IS). Apremilast was extracted from the plasma and urine samples by liquid–liquid extraction using methyl tert-butyl ether. Chromatographic separation was performed using a C8 column with gradient elution and a mobile phase containing methanol and 0.1% formic acid. Quantification was achieved in multiple reaction monitoring (MRM) mode with a transition of m/z 461.3→178.2 for apremilast and m/z 322.2→184.1 for clopidogrel (IS). This method was validated regarding its specificity, linearity, precision, accuracy, and stability. The lower limit of quantification (LLOQ) for this method was 5 ng/mL, and the calibration curve was linear over 5–1,000 ng/mL. The intra- and inter-run coefficients of variance (CV) of aprelimast in plasma samples were less than 12.92% and 10.64%, respectively, while in urine samples, the CV were less than 11.84% and 10.20%, respectively. The samples were stable under the tested conditions. This method was successfully applied to a pharmacokinetic study in beagle dogs following oral administration of 10 mg of apremilast.

Open access
Journal of Radioanalytical and Nuclear Chemistry
Authors:
Yinsong Wang
,
Aiguo Li
,
Yuanxun Zhan
,
Lun Wei
,
Yan Li
,
Guilin Zhang
,
Yaning Xie
,
Jing Zhang
,
Yuanmao Zhang
, and
Zuci Shan

Abstract  

The atmospheric particulate matter samples were collected in Shanghai, China. The X-ray absorption near-edge structure (XANES) spectra of Cr, Mn, Cu and Zn were measured. The XANES spectroscopy was used as a fingerprint to compare with that of reference materials to obtain speciation information. The oxidation state of these elements and main chemical components in the samples were described using the method. The results show that in our samples the oxidation state of Cr is trivalent, Mn mainly exists in the divalent state, Cu also exists in the divalent state, and Zn mainly exists in the zinc sulfate. For the XANES spectra of samples with different particle size and from different sampling site, we did not find their obvious differences. When we compared the XANES spectra of our samples with those of standard reference material SRM 1648, we found that they are similar in regards to the determined elements. The elemental concentrations in the samples were determined by proton induced X-ray emission (PIXE). The difference of elemental concentrations was observed in the different samples.

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Abstract

Splenic lymphocytes play an important role in host acute or chronic diseases. The abnormality of these cells in the spleens of humans might lead to some riskful diseases for human. Hence, in this study, the effects of two ginsenosides Rg1 and Rb1 on splenic lymphocytes growth were studied by microcalorimetry. Some qualitative and quantitative information, such as the metabolic power-time curves, growth rate constant k, maximum heat-output power of the exponential phase P max, total heat output Q t of splenic lymphocytes were obtained to present the effects of Rg1 and Rb1 on these cells. The values of k, P max, and Q t from the thermogenic growth curves of splenic lymphocytes were found to increase in the presence of Rg1, while the change was adverse for Rb1, illustrating that Rg1 had promotion effect and Rb1 had inhibitory effect on splenic lymphocytes growth and these promotion or inhibitory effects were enhanced with increasing the concentration of the two compounds, respectively. The microcalorimetric results were confirmed by MTT assay for determining the MTT optical density (OD) value and [3H] Thymidine incorporation assay ([3H]-TdR) for determining the count per minute (cpm) value: Rg1 could increase the MTT OD value and the cpm value of [3H]-TdR incorporation into splenic lymphocytes, and these values were increased with increasing the concentration of this compound, while Rb1 had the adverse results. The structure–activity relationships showed that the glucopyranoside and hydroxyl groups at the dammarane-type mother nucleus skeleton might play a crucial role for the opposing effects of the two ginsenosides on splenic lymphocytes. Compared with the other two assay methods, the microcalorimetric method provided more useful and reliable information for quickly and objectively evaluating the effects of drugs or compounds on the living cells, which would be a highly promising analytical tool for the characterization of the biological process and the estimation of the drugs’ efficiency.

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