Comparative Study of a Series of 99mTc(CO)3 Mannosylated Dextran Derivatives for Sentinel Lymph Node Detection

Sentinel lymph node detection (SLND) is rapidly entering common practice in the management of patients with tumors. The introduction of mannose molecules to ^99mTc-labeled dextrans, so far, showed that the sentinel node could trap these agents due to their recognition by the mannose receptors of lymph node macrophages. The current study aimed to synthesize, characterize, and biologically evaluate a series of mannosylated dextran derivatives labeled with ^99mTc for potential use in SLND. The compounds were designed to have a dextran with a molecular weight of 10–500 kDa as a backbone, S-derivatized cysteines, efficient SNO chelators, and mannose moieties for binding to mannose receptors. They were successfully synthesized, thoroughly characterized using NMR techniques, and labeled with the fac-[^99mTc(CO)₃]⁺ synthon. Labeling with high yields and radiochemical purities was achieved with all derivatives. In vivo biodistribution and imaging studies demonstrated high uptake in the first lymph node and low uptakes in the following node and confirmed the ability to visualize the SLN. Among the compounds studied, ^99mTc-D75CM demonstrated the most attractive biological features, and in combination with the high radiochemical yield and stability of the compound, its further evaluation as a new radiopharmaceutical for sentinel lymph node detection was justified.     

Natural and Nature-Derived Products Targeting Human Coronaviruses

The ongoing pandemic of severe acute respiratory syndrome (SARS), caused by the SARS-CoV-2 human coronavirus (HCoV), has brought the international scientific community before a state of emergency that needs to be addressed with intensive research for the discovery of pharmacological agents with antiviral activity. Potential antiviral natural products (NPs) have been discovered from plants of the global biodiversity, including extracts, compounds and categories of compounds with activity against several viruses of the respiratory tract such as HCoVs. However, the scarcity of natural products (NPs) and small-molecules (SMs) used as antiviral agents, especially for HCoVs, is notable. This is a review of 203 publications, which were selected using PubMed/MEDLINE, Web of Science, Scopus, and Google Scholar, evaluates the available literature since the discovery of the first human coronavirus in the 1960s; it summarizes important aspects of structure, function, and therapeutic targeting of HCoVs as well as NPs (19 total plant extracts and 204 isolated or semi-synthesized pure compounds) with anti-HCoV activity targeting viral and non-viral proteins, while focusing on the advances on the discovery of NPs with anti-SARS-CoV-2 activity, and providing a critical perspective.     

Photochemical Internalization of Tamoxifens Transported by a “Trojan‐Horse” Nanoconjugate into Breast‐Cancer Cell Lines

Photochemical internalization (PCI) has shown great promise as a therapeutic alternative for targeted drug delivery by light‐harnessed activation. However, it has only been applicable to therapeutic macromolecules or medium‐sized molecules. Herein we describe the use of an amphiphilic, water‐soluble porphyrin–β‐cyclodextrin conjugate (mTHPP‐βCD) as a “Trojan horse” to facilitate the endocytosis of CD‐guest tamoxifens into breast‐cancer cells. Upon irradiation, the porphyrin core of mTHPP‐βCD expedited endosomal membrane rupture and tamoxifen release into the cytosol, as documented by confocal microscopy. The sustained complexation of mTHPP‐βCD with tamoxifen was corroborated by 2D NMR spectroscopy and FRET studies. Following the application of PCI protocols with 4‐hydroxytamoxifen (4‐OHT), estrogen‐receptor β‐positive (Erβ+, but not ERβ?) cell groups exhibited extensive cytotoxicity and/or growth suspension even at 72 h after irradiation.     

Disequilibrium of dissolved <Superscript>234</Superscript>U/<Superscript>238</Superscript>U and <Superscript>210</Superscript>Po/<Superscript>210</Superscript>Pb in Greek rivers

For the first time, a radiological study for the dissolved ²³⁸U, ²³⁴U, ²¹⁰Pb and ²¹⁰Po was held in major Greek rivers across the country. ²³⁴U/²³⁸U activity ratios are above one in all samples and ²¹⁰Po/²¹⁰Pb activity ratios are respectively below the unit indicating the disequilibrium in the samples. Quite satisfactory correlations were observed among ²³⁴U and ²³⁸U as well as among ²¹⁰Po and ²¹⁰Pb values. Uranium isotopes were separated by ion exchange and electroplated on stainless steel plates. ²¹⁰Po was spontaneously deposited on nickel plates, while ²¹⁰Pb was indirectly determined through the ingrowth of ²¹⁰Po. The sources were measured by a-spectrometry.     

Semi-parallelism of normal Jacobi operator for Hopf hypersurfaces in complex two-plane Grassmannians

It is proved the non-existence of Hopf hypersurfaces in $G_{2}({\mathbb{C }}^{m+2}), m\ge 3$ , whose normal Jacobi operator is semi-parallel, if the principal curvature of the Reeb vector field is non-vanishing and the component of the Reeb vector field in the maximal quaternionic subbundle $\mathfrak{D }$ or its orthogonal complement $\mathfrak{D } ^{\bot }$ is invariant by the shape operator.     

Classification of real hypersurfaces in complex quadric in terms of new tensors

Periodica Mathematica Hungarica - In this paper two new tensor fields on real hypersurfaces in complex quadric are introduced. Real hypersurfaces on which the derivatives of the tensor fields with...     

DNA binding selectivity of oligopyridine-ruthenium(II)-lysine conjugate

The synthesis, characterization and DNA binding properties of the complex [Ru(terpy)(4,4'-(COLysCONH(2))(2)bpy)Cl](3+) (1) have been studied. Complex (1) hydrolyzes to (2) with a calculated rate constant K(h) = 2.35 ± 0.08 × 10(-4) s(-1) and binds coordinatively to ct-DNA, with a saturation r-value at about 0.1. Stabilization of the ct-DNA helix at low electrolyte (NaClO(4)) concentration (10 mM) and destabilization at higher electrolyte concentrations (50-200 mM) was observed. Circular dichroism studies indicate that the hydrolyzed complex binds to DNA, increasing the unwinding of the DNA helix with an unwinding angle calculated as Φ = 12 ± 2°. The positive LD signal observed at 350 nm indicates some kind of specificity in complex orientation towards the global DNA axis. Complex (2) binds specifically to G4 on the central part of the oligonucleotide duplexes d(CGCGCG)(2) and d(GTCGAC)(2), as evidenced by NMR spectroscopy. Both lysine moieties were found to interact most likely electrostatically with the DNA phosphates, assisting the coordinative binding and increasing the DNA affinity of the complex. Photoinduced DNA cleavage by (2), upon UVA irradiation was observed, but despite its relative high DNA affinity, it was incomplete (~12%).     

Vortex-assisted liquid-liquid microextraction of octylphenol, nonylphenol and bisphenol-A

A new and fast equilibrium-based solvent microextraction technique termed vortex-assisted liquid-liquid microextraction (VALLME) has been developed and used for the trace analysis of octylphenol, nonylphenol and bisphenol-A in water and wastewater samples. According to VALLME, dispersion of microvolumes of a low density extractant organic solvent into the aqueous sample is achieved by using for the first time vortex mixing, a mild emulsification procedure. The fine droplets formed could extract target analytes towards equilibrium faster because of the shorter diffusion distance and larger specific surface area. Upon centrifugation the floating extractant acceptor phase restored its initial single microdrop shape and was used for high-performance liquid chromatographic analysis. Different experimental parameters were controlled and the optimum conditions found were: 50 μl of octanol as the extractant phase; 20 ml aqueous donor samples; a 2 min vortex extraction time with the vortex agitator set at a 2500 rpm rotational speed; centrifugation for 2 min at 3500 rpm; no ionic strength or pH adjustment. The calculated calibration curves gave high levels of linearity yielding correlation coefficients (r²) greater than 0.9935. The repeatability and reproducibility of the proposed method were found to be good and the limits of the detection were calculated in the low μg l⁻¹ level ranging between 0.01 and 0.07 μg l⁻¹. Matrix effects were determined by applying the proposed method to spiked tap, river water and treated municipal wastewater samples. The proposed method was finally applied to the determination of target pollutants in real wastewater effluent samples using the standard addition method.     

Dendrons and Dendritic Terpolymers: Synthesis,Characterization and Self-Assembly Comparison

To the best of our knowledge, this is the very first time that a thorough study of the synthetic procedures, molecular and thermal characterization, followed by structure/properties relationship for symmetric and non-symmetric second generation (2-G) dendritic terpolymers is reported. Actually, the synthesis of the non-symmetric materials is reported for the first time in the literature. Anionic polymerization enables the synthesis of well-defined polymers that, despite the architecture complexity, absolute control over the average molecular weight, as well as block composition, is achieved. The dendritic type macromolecular architecture affects the microphase separation, because different morphologies are obtained, which do not exhibit long range order, and various defects or dislocations are evident attributed to the increased number of junction points of the final material despite the satisfactory thermal annealing at temperatures above the highest glass transition temperature of all blocks. For comparison reasons, the initial dendrons (miktoarm star terpolymer precursors) which are connected to each other in order to synthesize the final dendritic terpolymers are characterized in solution and in bulk and their self-assembly is also studied. A major conclusion is that specific structures are adopted which depend on the type of the core connection between the ligand and the active sites of the dendrons.