Preparation and properties of hybrid monodispersed magnetic α-Fe2O3 based chitosan nanocomposite film for industrial and biomedical applications

In this study, hydrothermally prepared magnetic α-Fe2O3 nanoparticles were dispersed in chitosan (CH) solution to fabricate nanocomposite film. X-ray diffraction (XRD) patterns indicated that the α-Fe2O3 nanoparticles were pure α-Fe2O3 with rhombohedral structures, and the fabrication of CH did not result in a phase change. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) results showed that the hexagonal and spherical monodispersed α-Fe2O3 nanoparticles were encapsulated into the spherical dumb shaped CH-α-Fe2O3 nanocomposite film with a mean diameter of ～87 and ～110 nm respectively. The α-Fe2O3 nanoparticles and CH-α-Fe2O3 nanocomposite film were also characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM). Magnetic measurements revealed that the saturated magnetization (Ms) and remanent magnetization (Mr) of the pure α-Fe2O3 nanoparticles reached 0.573 emu/g and 0.100 emu/g respectively and the nanoparticles showed the characteristics of weak ferromagnetic before and after coating with CH.     

An eco-friendly route of γ-Fe2O3 nanoparticles formation and investigation of the mechanical properties of the HPMC-γ-Fe2O3 nanocomposites

Bioprocess and Biosystems Engineering - In recent times, biosynthetic approaches toward the synthesis of nanoparticles have been shown to have several advantages over physical and chemical methods....     

Determination of insulin-like growth factor-I in the monitoring of growth hormone treatment with respect to efficacy of treatment and side effects: should potential risks of cardiovascular disease and cancer be considered?

Insulin-like growth factor (IGF)-I has proven to be important in the diagnosis of childhood-onset growth hormone (GH) deficiency (GHD). However, the variability of IGF-I should be taken into account before it can be used in a clinical setting. GH replacement therapy in GHD patients increases IGF-I into the normal range, although there is a large variation. Excessively high (supranormal) GH-induced IGF-I levels are associated with increased prevalence of side effects in adults with GHD. Consequently, at most centres, GH doses are titrated according to IGF-I levels in GHD adults. Whether or not this should also be done in children has not been established. Due to the known variability of IGF-I, individual changes in IGF-I must exceed approximately 35% to be sufficiently significant to warrant a dose adjustment. Novel epidemiological studies have suggested that higher IGF-I levels are associated with an increased risk of prostate, breast and colorectal cancer compared with lower IGF-I levels in otherwise healthy subjects. Consequently, life-time exposure to IGF-I should be considered in all patients treated with GH, and IGF-I should preferably be kept within normal age-related ranges in children as well as in adults.     

A comparison of two subarachnoid α2-agonists,xylazine and clonidine,with respect to duration of antinociception,and hemodynamic effects in goats

Subarachnoid administration of clonidine and xylazine produces antinociception in several species and in humans. The present study compares these two drugs administered by the subarachnoid route to goats. Goats (n=6) were randomly assigned to three treatment groups. All animals of each group received 0.06 mg kg⁻¹ clonidine (CLO), 0.1 mg kg⁻¹ xylazine (XIL) and 0.9% saline solution (SS), with a minimum interval of 1 week between treatments. All injections were made into the subarachnoid space between the last lumbar vertebra and the first sacral vertebra. Analgesia, ataxia, sedation, cardiovascular and respiratory effects, and rectal temperature were evaluated at predefined regular time intervals before drug administration (baseline) and after administration. The onset of analgesia by clonidine and xylazine was observed in 6.8±1.8 and 9.5±2.6 min (mean±S.D.), respectively. Both α₂-agonists produced analgesia of dorsocaudal rib areas, flanks, hind limbs, perineum and tail, sedation and ataxia. The duration of antinociception after clonidine administration was 118.8±24 min and after xylazine 88.3±15 min (mean±S.D.). Clonidine and xylazine subarachnoidally administered induced a significant (P<0.05) decrease in heart and respiratory rates and hypothermia in relation to the basal value. Neither drug significantly altered blood pressure. Both α₂-agonist drugs induced frequent diuresis and an increase in salivation. We conclude that subarachnoid clonidine produces longer antinociception with less ataxia than xylazine in goats. However, the drug induced bradycardia, a decrease in the respiratory rate and hypothermia, with a small compromise in the blood pressures at the doses studied. Further studies should be done to determine whether this analgesia is sufficient for surgical procedures.     

Orange luminescence of α-Al2O3 related to clusters consisting of F centers and divalent cations

The orange luminescence of α-Al₂O₃ under UV excitation is characterized by a 2.07-eV orange broadband emission that has not yet been elucidated. This emission is present in natural and synthetic crystals and powders, as well as in Be-treated samples. All orange-luminescent materials have low Fe concentration (mostly <1000 ppm) with traces of divalent cations, mostly Mg, or Be in Be-diffused material (dozens of ppm). Mg²⁺, Mn²⁺, and Be²⁺ cations substitute for trivalent Al. To accommodate the charge deficit, several defects are created, including oxygen vacancies also called F centers. Indeed, our excitation spectra revealed the presence of several different F centers (F, F⁺, and clustered F₂, F₂⁺, F₂²⁺) in those samples. However, the thermal stability and the measured luminescence lifetimes do not match with previously reported characteristics of isolated F centers. Based on our experiments, we suggest that a complex aggregate of two F centers (F₂²⁺) trapped at divalent cations is a major cause of this uncommon microsecond lifetime emission, even if a variety of other defects, including Cr³⁺, V³⁺, or interstitial Al³⁺, are present.     

Role of α5β1 and αvβ3 integrins in relation to adhesion and spreading dynamics of prostate cancer cells interacting with fibronectin under in vitro conditions

Interaction of cell integrins with the ECM (extracellular matrix) proteins is commonly assumed to be associated with cell dissemination and tumour metastases. Since these processes depend on the mechanism of cell-protein interaction, we have attempted to show the contribution of α5β1 and αvβ3 integrins of the prostate cancer PC-3 cells in in vitro interaction with FN (fibronectin) adsorbed on defined polystyrene surfaces. Cell adhesion, spreading and cytoskeleton organization were studied using antibodies against integrins or a GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro) peptide. The results show that blocking the α5β1 integrin causes: (i) a decrease in the number of the adherent cells in the early phase of adhesion and (ii) a decrease in the dynamics of cell spreading and cell shape changes, and weaker reorganization of cytoskeletal proteins than in the control cells. Conversely, the blocking of the αvβ3 integrin: (i) causes no observable effect on the number of the adhered cells; however, (ii) causes an increase in the dynamics of cell spreading and cell shape changes, and stronger reorganization of cytoskeletal proteins than in the control cells. Interestingly, the blocking of integrins with a GRGDSP peptide strongly decreases the number of the adhered cells, and a complete inhibition of cell spreading. Our results strongly suggest that the α5β1 integrin plays the main role in the adhesion and spreading of PC-3 cells interacting with FN, whereas the αvβ3 integrin seems to regulate other receptors in the spreading process. Moreover, integrin-FN interaction through the RGD sequence evidently curbed the cell adhesion and spreading.     

Reduction of oxidative stress and ornithine decarboxylase expression in a human prostate cancer cell line PC-3 by a combined treatment with α-tocopherol and naringenin

Amino Acids - Differentiation of a human aggressive PC-3 cancer cell line was obtained, in a previous investigation, by the synergic effect of α-tocopherol (α-TOC) and naringenin (NG)....     

Multiorgan metastasis of human HER-2⁺ breast cancer in Rag2⁻/⁻;Il2rg⁻/⁻ mice and treatment with PI3K inhibitor

In vivo studies of the metastatic process are severely hampered by the fact that most human tumor cell lines derived from highly metastatic tumors fail to consistently metastasize in immunodeficient mice like nude mice. We describe a model system based on a highly immunodeficient double knockout mouse, Rag2?/?;Il2rg?/?, which lacks T, B and NK cell activity. In this model human metastatic HER-2? breast cancer cells displayed their full multiorgan metastatic potential, without the need for selections or additional manipulations of the system. Human HER-2? breast cancer cell lines MDA-MB-453 and BT-474 injected into Rag2?/?;Il2rg?/? mice faithfully reproduced human cancer dissemination, with multiple metastatic sites that included lungs, bones, brain, liver, ovaries, and others. Multiorgan metastatic spread was obtained both from local tumors, growing orthotopically or subcutaneously, and from cells injected intravenously. The problem of brain recurrencies is acutely felt in HER-2? breast cancer, because monoclonal antibodies against HER-2 penetrate poorly the blood-brain barrier. We studied whether a novel oral small molecule inhibitor of downstream PI3K, selected for its penetration of the blood-brain barrier, could affect multiorgan metastatic spread in Rag2?/?; Il2rg?/? mice. NVP-BKM120 effectively controlled metastatic growth in multiple organs, and resulted in a significant proportion of mice free from brain and bone metastases. Human HER-2? human breast cancer cells in Rag2?/?;Il2rg?/? mice faithfully reproduced the multiorgan metastatic pattern observed in patients, thus allowing the investigation of metastatic mechanisms and the preclinical study of novel antimetastatic agents.     

Phallus impudicus loaded with γ-Fe2O3 as solid phase bioextractor for the preconcentrations of Zn(II) and Cr(III) from water and food samples

We investigated the application of fungus Phallus impudicus loaded γ-Fe₂O₃ nanoparticles as a biosorbent for magnetic solid phase extractions of trace levels of Zn(II) and Cr(III) ions from natural samples before their measurements by inductively coupled plasma optical emission spectrometry. The characterization of magnetized P. impudicus was performed using the scanning electron microscope, the energy dispersive X-ray and Fourier transform infrared spectroscopy. Important experimental factors were investigated. The experimental results fitted well to the Langmuir adsorption model and pseudo-second order kinetic model. Limit of detections of targeted ions by magnetic solid phase extraction method based on use of P. impudicus were found as 10.5 ngL⁻¹ and 12.6 ngL⁻¹ respectively for Cr(III) and Zn(II). The sorption capacities of the biosorbent were 22.8 mgg⁻¹ for Cr(III) and 25.6 mgg⁻¹ for Zn(II). The preconcentration factors were achieved as 100 for both of ions. RSDs for inter- and intraday precisions were found as lower than 2.0% and 2.1% respectively for both of targeted ions. The accuracy of the recommended process was tested by recovery measurements on the certificated reference materials and successfully applied for quantification recoveries of Cr(III) and Zn(II) ions from water and food samples.     

Pilot trial of interleukin-2 and zoledronic acid to augment γδ T cells as treatment for patients with refractory renal cell carcinoma

Prior to the advent of VEGF-targeted therapies, renal cell carcinoma (RCC) was among the few solid tumors shown to respond to cytokine-based therapies such as interleukin-2 (IL-2) and interferon alpha. Previous work has shown that aminobisphosphonates, including zoledronic acid (ZA), are capable of activating human Vγ9 Vδ2 T cells in vitro, and these cells can be further expanded with IL-2. Moreover, these Vγ9 Vδ2 T cells have cytolytic activity in vitro to multiple human tumor cell lines. In the current report, we have conducted a pilot trial in patients with metastatic RCC, evaluating different doses of ZA in combination with low-dose IL-2 to determine whether combining these agents can promote in vivo proliferation of Vγ9 Vδ2 T cells and elicit an antitumor response. In 12 patients evaluated, no objective clinical responses were observed by RECIST criteria; however, two patients experienced prolonged stable disease. A modest increase in Vγ9 Vδ2 T-cell frequency could be detected by Day 8 of therapy in four of the nine patients who received at least one cycle of therapy, but not to the magnitude anticipated from preclinical models. Repeated administration of IL-2 and ZA resulted in both a diminished in vivo percentage of Vγ9 Vδ2 T cells as well as impaired expansion in vitro after the first cycle of therapy. These results suggest that repeated administration of IL-2 and ZA, at the doses and schedules used in this trial, may actually inhibit the proliferative capacity of Vγ9 Vδ2 T cell in patients with metastatic RCC.     

Proteomic identification of predictive biomarkers of resistance to neoadjuvant chemotherapy in luminal breast cancer: a possible role for 14-3-3 theta/tau and tBID?

Introduction

Chemotherapy resistance is a major obstacle in effective neoadjuvant treatment for estrogen receptor-positive breast cancer. The ability to predict tumour response would allow chemotherapy administration to be directed towards only those patients who would benefit, thus maximising treatment efficiency. We aimed to identify putative protein biomarkers associated with chemotherapy resistance, using fresh tumour samples with antibody microarray analysis and then to perform pilot clinical validation experiments.

Materials and methods

Chemotherapy resistant and chemotherapy sensitive tumour samples were collected from breast cancer patients who had received anthracycline based neoadjuvant therapy consisting of epirubicin with cyclophosphamide followed by docetaxel. A total of 5 comparative proteomics experiments were performed using invasive ductal carcinomas which demonstrated estrogen receptor positivity (luminal subtype). Protein expression was compared between chemotherapy resistant and chemotherapy sensitive tumour samples using the Panorama XPRESS Profiler725 antibody microarray containing 725 antibodies from a wide variety of cell signalling and apoptosis pathways. A pilot series of archival samples was used for clinical validation of putative predictive biomarkers.

Results

AbMA analysis revealed 38 differentially expressed proteins which demonstrated at least 1.8 fold difference in expression in chemotherapy resistant tumours and 7 of these proteins (Zyxin, 14-3-3 theta/tau, tBID, Pinin, Bcl-xL, RIP and MyD88) were found in at least 2 experiments. Clinical validation in a pilot series of archival samples revealed 14-3-3 theta/tau and tBID to be significantly associated with chemotherapy resistance.

Conclusions

For the first time, antibody microarrays have been used to identify proteins associated with chemotherapy resistance using fresh breast cancer tissue. We propose a potential role for 14-3-3 theta/tau and tBID as predictive biomarkers of neoadjuvant chemotherapy resistance in breast cancer. Further validation in a larger sample series is now required.     

Correction for Inhibition Leads to an Allosteric Co-Agonist Model for Pentobarbital Modulation and Activation of α1β3γ2L GABAA Receptors

BackgroundPentobarbital, like propofol and etomidate, produces important general anesthetic effects through GABA_A receptors. Photolabeling also indicates that pentobarbital binds to some of the same sites where propofol and etomidate act. Quantitative allosteric co-agonist models for propofol and etomidate account for modulatory and agonist effects in GABA_A receptors and have proven valuable in establishing drug site characteristics and for functional analysis of mutants. We therefore sought to establish an allosteric co-agonist model for pentobarbital activation and modulation of α1β3γ2L receptors, using a novel approach to first correct pentobarbital activation data for inhibitory effects in the same concentration range.MethodsUsing oocyte-expressed α1β3γ2L GABA_A receptors and two-microelectrode voltage-clamp, we quantified modulation of GABA responses by a low pentobarbital concentration and direct effects of high pentobarbital concentrations, the latter displaying mixed agonist and inhibitory effects. We then isolated and quantified pentobarbital inhibition in activated receptors using a novel single-sweep “notch” approach, and used these results to correct steady-state direct activation for inhibition.ResultsCombining results for GABA modulation and corrected direct activation, we estimated receptor open probability and optimized parameters for a Monod-Wyman-Changeux allosteric co-agonist model. Inhibition by pentobarbital was consistent with two sites with IC₅₀s near 1 mM, while co-agonist model parameters suggest two allosteric pentobarbital agonist sites characterized by K_PB ≈ 5 mM and high efficacy. The results also indicate that pentobarbital may be a more efficacious agonist than GABA.ConclusionsOur novel approach to quantifying both inhibitory and co-agonist effects of pentobarbital provides a basis for future structure-function analyses of GABA_A receptor mutations in putative pentobarbital binding sites.     

Synthesis and biological evaluation of both enantiomers of [18F]flubatine,promising radiotracers with fast kinetics for the imaging of α4β2-nicotinic acetylcholine receptors

Both enantiomers of the epibatidine analogue flubatine display high affinity towards the α4β2 nicotinic acetylcholine receptor (nAChR) in vitro, accompanied by negligible interactions with diverse off-target proteins. Extended single dose toxicity studies in rodent indicated a NOEL (No Observed Effect Level) of 6.2 μg/kg for (−)-flubatine and 1.55 μg/kg for (+)-flubatine. We developed syntheses for both flubatine enantiomers and their corresponding precursors for radiolabeling. The newly synthesized trimethylammonium precursors allowed for highly efficient ¹⁸F-radiolabelling in radiochemical yields >60% and specific activities >750 GBq/μmol, thus making the radioligands practical for clinical investigation.     

What factors are responsible for the greater yield of ATP per carbon atom when fatty acids are completely oxidised to CO2 and water compared with glucose?

Some current textbooks of biochemistry present calculations which indicate that when palmitic or stearic acid is completely oxidised to CO₂ and water, more molecules of ATP are produced per carbon atom than when glucose is similarly oxidised. This greater yield of ATP is not due to ATP produced as a result of the β-oxidative process, but rather due to the increased yield of acetyl-CoA molecules produced from fatty acids (3 acetyl-CoA molecules per 6 carbon atoms) compared with that produced from glucose (2 acetyl-CoA molecules per 6 carbon atoms).     

Resolution of α, β and γ DNA of Saccharomyces cerevisiae with the antitumor drug cis-Pt(NH3)2Cl2. Evidence for preferential drug binding by GpG sequences of DNA

This paper reports further studies on the separation of DNAs with the antitumor drug cis-Pt(NH₃)₂Cl₂. cis-Pt(NH₃)₂Cl₂ permits resolution of the three DNA components from whole Saccharomyces cerevisiae in CsCl gradients, avoids pelleting of mitochondrial (β) DNA and does not require a critical molar ratio of platinum drug to DNA-P. However, the difficulty in removing all of the DNA-bound platinum may limit its preparative use. The linear relationship between the increase in buoyant density of platinized double-stranded DNA and its G + C content is employed to calculate a G + C content of 41.2% and 45.8% for α and γ DNA, respectively, using a value of 20% G + C for β DNA. In parallel experiments, we find that poly(dG)·poly(dC), which contains sequential guanine bases, exhibits an unexpectedly large buoyant density increase with cis-Pt(NH₃)₂ Cl₂, while the buoyant density increase of poly[d(G-C)]is markedly retarded, indicating an effect of nucleotide base sequence on DNA separation. The trans platinum compound, which has no antitumor properties, separates DNAs on the basis of G + C content in a similar fashion, but does not preferentially increase the buoyant density of poly(dG)·poly(dC).     

Essential structure of opioid κ receptor agonist nalfurafine for binding to the κ receptor 3: Synthesis of decahydro(iminoethano)phenanthrene derivatives with an oxygen functionality at the 3-position and their pharmacologies

To clarify the essential structures of an opioid κ receptor selective agonist, nalfurafine, for binding to the κ receptor, we designed and synthesized the decahydro(iminoethano)phenanthrene derivatives with an oxygen functionality at the 3-position. The introduction of a hydroxy group to the derivatives increased the affinity and selectivity to the κ receptor regardless of the configuration at the 3-position. However, their affinities were lower than those of nalfurafine with the phenolic hydroxy group. The results suggested that the acidity of the hydroxy group would play an important role in the interaction with the opioid receptor. The low affinities of the 3-keto derivatives indicated that the 3-hydroxy group may participate in the hydrogen bonding with the receptor site not as a hydrogen acceptor but as a hydrogen donor. This is the first experimental evidence for a role as a hydrogen donor for the 3-hydroxy group in morphinans. Furthermore, the κ selectivities in these derivatives with the 6α-amide side chain were affected by the the 3-hydroxy group. The obtained structure–activity relationship information is expected to be useful for the design of more selective ligands for the κ receptor.     

Synthesis and biological evaluation of novel carbon-11 labeled pyridyl ethers: candidate ligands for in vivo imaging of α4β2 nicotinic acetylcholine receptors (α4β2-nAChRs) in the brain with positron emission tomography

The most abundant subtype of cerebral nicotinic acetylcholine receptors (nAChR), α4β2, plays a critical role in various brain functions and pathological states. Imaging agents suitable for visualization and quantification of α4β2 nAChRs by positron emission tomography (PET) would present unique opportunities to define the function and pharmacology of the nAChRs in the living human brain. In this study, we report the synthesis, nAChR binding affinity, and pharmacological properties of several novel 3-pyridyl ether compounds. Most of these derivatives displayed a high affinity to the nAChR and a high subtype selectivity for α4β2-nAChR. Three of these novel nAChR ligands were radiolabeled with the positron-emitting isotope ¹¹C and evaluated in animal studies as potential PET radiotracers for imaging of cerebral nAChRs with improved brain kinetics.