Repair, regenerative and supportive therapies of the annulus fibrosus: achievements and challenges

Lumbar discectomy is a very effective therapy for neurological decompression in patients suffering from sciatica due to hernia nuclei pulposus. However, high recurrence rates and persisting post-operative low back pain in these patients require serious attention. In the past decade, tissue engineering strategies have been developed mainly targeted to the regeneration of the nucleus pulposus (NP) of the intervertebral disc. Accompanying techniques that deal with the damaged annulus fibrous are now increasingly recognised as mandatory in order to prevent re-herniation to increase the potential of NP repair and to confine NP replacement therapies. In the current review, the requirements, achievements and challenges in this quickly emerging field of research are discussed

Lipid Composition of the Human Eye: Are Red Blood Cells a Good Mirror of Retinal and Optic Nerve Fatty Acids?

International audienceBACKGROUND: The assessment of blood lipids is very frequent in clinical research as it is assumed to reflect the lipid composition of peripheral tissues. Even well accepted such relationships have never been clearly established. This is particularly true in ophthalmology where the use of blood lipids has become very common following recent data linking lipid intake to ocular health and disease. In the present study, we wanted to determine in humans whether a lipidomic approach based on red blood cells could reveal associations between circulating and tissue lipid profiles. To check if the analytical sensitivity may be of importance in such analyses, we have used a double approach for lipidomics. METHODOLOGY AND PRINCIPAL FINDINGS: Red blood cells, retinas and optic nerves were collected from 9 human donors. The lipidomic analyses on tissues consisted in gas chromatography and liquid chromatography coupled to an electrospray ionization source-mass spectrometer (LC-ESI-MS). Gas chromatography did not reveal any relevant association between circulating and ocular fatty acids except for arachidonic acid whose circulating amounts were positively associated with its levels in the retina and in the optic nerve. In contrast, several significant associations emerged from LC-ESI-MS analyses. Particularly, lipid entities in red blood cells were positively or negatively associated with representative pools of retinal docosahexaenoic acid (DHA), retinal very-long chain polyunsaturated fatty acids (VLC-PUFA) or optic nerve plasmalogens. CONCLUSIONS AND SIGNIFICANCE: LC-ESI-MS is more appropriate than gas chromatography for lipidomics on red blood cells, and further extrapolation to ocular lipids. The several individual lipid species we have identified are good candidates to represent circulating biomarkers of ocular lipids. However, further investigation is needed before considering them as indexes of disease risk and before using them in clinical studies on optic nerve neuropathies or retinal diseases displaying photoreceptors degeneration

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

Chemical leaching of Pt–Cu/C catalysts for electrochemical oxygen reduction:activity, particle structure, and relation to electrochemical leaching

\u3cp\u3eCarbon-supported Pt–Cu alloy nanoparticles (Cu/Pt=2.6 on average) were obtained by a liquid precursor impregnation–reduction technique, with alloying in dilute hydrogen at 800 °C. They were subjected to leaching (chemical—CL: 1 m H\u3csub\u3e2\u3c/sub\u3eSO\u3csub\u3e4\u3c/sub\u3e, 80 °C for 36 h, electrochemical—EL: 200 times potential cycling between 0.05 and 1.2 V in 0.1 m HClO\u3csub\u3e4\u3c/sub\u3e) to study the influence of leaching on their activity in the oxygen reduction reaction (ORR) and on particle structure, in particular, for the chemical route that provided sufficient material for the characterization techniques employed (X-ray diffraction, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, low-energy ion scattering). CL resulted in core–shell-structured nanoparticles, in which an external monolayer of pure Pt covered an alloy core significantly depleted in Cu. Cu/Pt ratios in the cores were distributed around Cu/Pt=0.4–1, which differs from particle architectures described in the literature as a result of EL. The alloy superstructure initially present was destroyed. A minority of pure Pt particles, probably very small in size, coexisted with the alloy particles. The specific ORR activity of these leached nanoparticles was twice that of the original Pt–Cu alloy particles (264 vs. 140 μA cm\u3csup\u3e−2\u3c/sup\u3e Pt). Electrochemical leaching applied to the initial particles or to the chemically dealloyed ones also resulted in activation (direct EL −175 μA cm\u3csup\u3e−2\u3c/sup\u3e Pt, EL after CL −315 μA cm\u3csup\u3e−2\u3c/sup\u3e Pt). Particles with a Cu-depleted alloy core (EL after CL) provided higher activity after EL.\u3c/p\u3