Self-Assembled Polymeric Micellar Nanoparticles as Nanocarriers for Poorly Soluble Anticancer Drug Ethaselen

A series of monomethoxy poly(ethylene glycol)-poly(lactide) (mPEG-PLA) diblock copolymers were synthesized, and mPEG-PLA micelle was fabricated and used as a nanocarrier for solubilization and delivery of a promising anticancer drug ethaselen. Ethaselen was efficiently encapsulated into the micelles by the dialysis method, and the solubility of ethaselen in water was remarkably increased up to 82 μg/mL before freeze-drying. The mean diameter of ethaselen-loaded micelles ranged from 51 to 98 nm with a narrow size distribution and depended on the length of PLA block. In vitro hemolysis study indicated that mPEG-PLA copolymers and ethaselen-loaded polymeric micelles had no hemolytic effect on the erythrocyte. The enhanced antitumor efficacy and reduced toxic effect of ethaselen-loaded polymeric micelle when compared with ethaselen-HP-β-CD inclusion were observed at the same dose in H22human liver cancer cell bearing mouse models. These suggested that mPEG-PLA polymeric micelle nanoparticles had great potential as nanocarriers for effective solubilization of poorly soluble ethaselen and further reducing side effects and toxicities of the drug

Enhancement of Cell Membrane Invaginations, Vesiculation and Uptake of Macromolecules by Protonation of the Cell Surface

The different pathways of endocytosis share an initial step involving local inward curvature of the cell’s lipid bilayer. It has been shown that to generate membrane curvature, proteins or lipids enforce transversal asymmetry of the plasma membrane. Thus it emerges as a general phenomenon that transversal membrane asymmetry is the common required element for the formation of membrane curvature. The present study demonstrates that elevating proton concentration at the cell surface stimulates the formation of membrane invaginations and vesiculation accompanied by efficient uptake of macromolecules (Dextran-FITC, 70 kD), relative to the constitutive one. The insensitivity of proton induced uptake to inhibiting treatments and agents of the known endocytic pathways suggests the entry of macromolecules to proceeds via a yet undefined route. This is in line with the fact that neither ATP depletion, nor the lowering of temperature, abolishes the uptake process. In addition, fusion mechanism such as associated with low pH uptake of toxins and viral proteins can be disregarded by employing the polysaccharide dextran as the uptake molecule. The proton induced uptake increases linearly in the extracellular pH range of 6.5 to 4.5, and possesses a steep increase at the range of 4> pH>3, reaching a plateau at pH≤3. The kinetics of the uptake implies that the induced vesicles release their content to the cytosol and undergo rapid recycling to the plasma membrane. We suggest that protonation of the cell’s surface induces local charge asymmetries across the cell membrane bilayer, inducing inward curvature of the cell membrane and consequent vesiculation and uptake

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A

On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance is $5.0\times {10}^{-8}$. We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of $(+1.74\pm 0.05)\,{\rm{s}}$ between GRB 170817A and GW170817 to: (i) constrain the difference between the speed of gravity and the speed of light to be between $-3\times {10}^{-15}$ and $+7\times {10}^{-16}$ times the speed of light, (ii) place new bounds on the violation of Lorentz invariance, (iii) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1-1.4 per year during the 2018-2019 observing run and 0.3-1.7 per year at design sensitivity

First Measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary-Black-hole Merger GW170814

We present a multi-messenger measurement of the Hubble constant H 0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in ${H}_{0}={75}_{-32}^{+40}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$, which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s−1 Mpc−1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s−1 Mpc−1, we find {H}_{0 {78}_{-24}^{+96}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1} (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0

The in vitro effects of low molecular weight serum fractions on embryonic Wistar rat (Rattus norvegicus) development

The in vitro embryo culture technique has been used in many research areas as well as for teratologic and toxicologic tests. Usually, homologous serum is used as a culture medium in these techniques. In this study, the effects of low molecular weight serum fractions on embryonic rat development were tested. Using 30 and 50 kDa Macrosep centrifugal concentrators, the homologous serum was centrifuged for 8 h to separate the low molecular weight serum fractions. The embryos were cultured in the sera which included > 30 kDa, > 50 kDa and 50 kDa serum fractions. Whole rat serum (WRS) was also used for control. After a 48-h culture period, embryonic growth and development were assessed using a morphologic scoring system and the protein content of embryos and yolk sacs. The results showed that the embryonic growth and development during organogenesis significantly decreased in > 30 kDa and > 50 kDa serum fractions when compared to WRS. Addition of a 50 kDa serum fraction improved the embryonic growth, but not to the level seen in embryos grown in WRS. While morphological scores for the embryos grown in WRS, > 30 kDa, > 50 kDa and 50 kDa serum fractions were 57.5 +/- 0.83, 44.53 +/- 1.06, 37.81 +/- 1.9 and 45.14 +/- 1.56, respectively, somite numbers were 26.4 +/- 0.28, 20.47 +/- 0.46, 19.15 +/- 0.58 and 21.78 +/- 0.5, yolk sac diameters were 3.35 +/- 0.06, 2.89 +/- 0.05, 2.61 +/- 0.03 and 2.71 +/- 0.04 mm, crown-rump lengths were 3.03 +/- 0.06, 2.72 +/- 0.04, 2.36 +/- 0.04 and 2.52 +/- 0.04 mm, embryo protein contents were 160.93 +/- 6.88, 119.07 +/- 5.15, 67.23 +/- 3.87 and 98.72 +/- 4.87 mu g and yolk sac protein contents were 114.87 +/- 5.18, 86.33 +/- 1.92, 62.38 +/- 2.7 and 75.88 +/- 2.87 mu g, respectively. These results suggest that low molecular weight serum fractions could be very important for normal embryonic development

Labelling of rat endothelial cells with antibodies to vWF, RECA-1, PECAM-1, ICAM-1, OX-43 and ZO-1

Labelling with endothelium specific monoclonal antibodies, von Willebrand Factor (vWF), rat endothelial cell antigen-1 (RECA-1), platelet-endothelial cell adhesion molecule-1 (PECAM-1), intercellular adhesion molecule-1 (ICAM-1). OX-43 and zonula occludentes-1 (ZO-1), was investigated in cryostat sections of vessels From rats of different ages using a confocal microscope. The results showed that labelling of the vWF was positive in endothelial cells from adult, fetal and different ages of embryonic rat. Labelling with RECA-1 was weakly positive in adult rat aorta and lung endothelial cells but not in embryonic yolk sac endothelial cells. Labelling using PECAM-1. ICAM-I and OX-43 as negative in both adult and embryonic endothelial cells. ZO-1 showed positive but very weak reactivity in embryonic yolk sac endothelial cells. The expression of vWF on vessels from adult and 19.5-day Fetal tissues was strongly positive, However, the expression of vWF in embryonic endothelial cells was dependent on the gestational age, While the 11.5-day yolk sac vessels stained weakly, staining gradually increased in 13.5-. 15.5- and 17.5-day-old yolk sac vessels. The results Suggest that vWF is a reliable endothelial cell marker in rat vascular endothelial cells, including both fetal and embryonic stages

Protection by free oxygen radical scavenging enzymes against salicylate-induced embryonic malformations in vitro

Salicylates are among the oldest and most widely used drugs and are known to lead to foetal death, growth retardation and congenital abnormalities in experimental animals. In this study, the effects of acetyl salicylic acid (ASA), salicylic acid (SAL) and sodium salicylate (NaSAL) on early organogenesis and the interaction of these molecules with free radicals has been investigated. Postimplantation rat embryos were cultured in vitro from day 9.5 of gestation for 48 hr. ASA, SAL and NaSAL were added to whole rat serum at concentrations between 0.1 and 0.6 mg/ml. Also, the lowest effective concentration of ASA for all parameters (0.3 mg/ml) and the same concentration of NaSAL and SAL was added to the culture media in the presence of superoxide dismutase (SOD) (30 U/ml) or glutathione (0.5 mu mol/ml). The growth and development of embryos was compared and each embryo was evaluated for the presence of any malformations. When compared to growth of control embryos, the salicylates decreased all growth and developmental parameters in a concentration-responsive manner. There was also a concentration-related increase in overall dysmorphology, including the incidence of haematoma in the yolk sac and neural system, open neural tube, abnormal tail torsion and the absence of fore limb bud. When SOD was added in the presence of ASA, growth and developmental parameters were improved and there was a significant decrease in the incidence of malformations. Addition of SOD also decreased the incidence of malformations in the presence of SAL, but did not effect the growth and developmental parameters of SAL and NaSAL. There was no significant difference between the embryos grown in the presence of these three molecules on the addition of glutathione. The effects of salicylates might involve free oxygen radicals by the non-enzymatic production of the highly teratogenic metabolites 2,3- and 2,5-dihydroxybenzoic acid. An enhanced production of these metabolites in embryonic tissues may be directly related to the increased risk of congenital malformations. (C) 2000 Published by Elsevier Science Ltd