Neuroprotective effects of bis(7)-tacrine against glutamate-induced retinal ganglion cells damage

<p>Abstract</p> <p>Background</p> <p>Glutamate-mediated excitotoxicity, primarily through N-methyl-D-aspartate (NMDA) receptors, may be an important cause of retinal ganglion cells (RGCs) death in glaucoma and several other retinal diseases. Bis(7)-tacrine is a noncompetitive NMDA receptors antagonist that can prevent glutamate-induced hippocampal neurons damage. We tested the effects of bis(7)-tacrine against glutamate-induced rat RGCs damage in vitro and in vivo.</p> <p>Results</p> <p>In cultured neonatal rats RGCs, the MTT assay showed that glutamate induced a concentration- and time-dependent toxicity. Bis(7)-tacrine and memantine prevented glutamate-induced cell death in a concentration-dependent manner with IC50 values of 0.028 μM and 0.834 μM, respectively. The anti-apoptosis effects of bis(7)-tacrine were confirmed by annexin V-FITC/PI staining. In vivo, TUNEL analysis and retrograde labeling analysis found that pretreatment with bis(7)-tacrine(0.2 mg/kg) induced a significant neuroprotective effect against glutamate-induced RGCs damage.</p> <p>Conclusions</p> <p>Our results showed that bis(7)-tacrine had neuroprotective effects against glutamate-induced RGCs damage in vitro and in vivo, possibly through the drug's anti-NMDA receptor effects. These findings make bis(7)-tacrine potentially useful for treating a variety of ischemic or traumatic retinopathies inclusive of glaucoma.</p

An updated determination of the pion-photon transition form factor

In this paper, we study the properties of the pion-photon transition form factor (TFF), $\gamma\gamma^{\ast} \rightarrow \pi^{0}$, by using the principle of maximum commonality (PMC) to deal with its perturbative QCD contribution up to next-to-next-to-leading order (NNLO) QCD corrections. Applying the PMC, we achieve precise pQCD approximant for the TFF in large $Q^2$-region without conventional renormalization scale ambiguity. We also discuss the power suppressed non-valence quark contribution to the TFF, which is important for a sound prediction in low and intermediate $Q^2$-region, e.g. the non-valence quark components affect the TFF by about $1\%$ to $23\%$ when $Q^{2}$ changes down from $40~{\rm GeV^{2}}$ to $4~{\rm GeV^{2}}$. The resultant pion-photon TFF shows a better agreement with previous Belle data. It is hoped that previous discrepancies between the experimental measurements and theoretical predictions could be clarified by the forth-coming precise data on the Belle II measurements.Comment: 7 pages, 6 figure

Strong decays of the ϕ(2170)\phi(2170) as a fully-strange tetraquark state

We study strong decays of the $\phi(2170)$, along with its possible partner $X(2436)$, as two fully-strange tetraquark states of $J^{PC} = 1^{--}$. We consider seven decay channels: $\phi \eta$, $\phi \eta^\prime$, $\phi f_0(980)$, $\phi f_1(1420)$, $h_1(1415) \eta$, $h_1(1415) \eta^\prime$, and $h_1(1415) f_1(1420)$. Some of these channels are kinematically possible, and we calculate their relative branching ratios through the Fierz rearrangement. Future experimental measurements on these ratios can be useful in determining the nature of the $\phi(2170)$ and $X(2436)$. The $\phi(2170)$ has been observed in the $\phi f_0(980)$, $\phi \eta$, and $\phi \eta^\prime$ channels, and we propose to further examine it in the $h_1(1415) \eta$ channel. Evidences of the $X(2436)$ have been observed in the $\phi f_0(980)$ channel, and we propose to verify whether this structure exists or not in the $\phi \eta$, $\phi \eta^\prime$, $h_1(1415) \eta$, and $h_1(1415) \eta^\prime$ channels.Comment: 10 pages, 3 figures, 1 table, suggestions and comments are welcom

Fully-strange tetraquark states with the exotic quantum numbers JPC=0+−J^{PC} = 0^{+-} and 2+−2^{+-}

We study the fully-strange tetraquark states with the exotic quantum numbers $J^{PC} = 0^{+-}$ and $2^{+-}$. We construct their corresponding diquark-antidiquark interpolating currents, and apply the QCD sum rule method to calculate both their diagonal and off-diagonal correlation functions. The obtained results are used to construct some mixing currents that are nearly non-correlated, from which we extract the masses of the lowest-lying states to be $M_{0^{+-}} = 2.45^{+0.33}_{-0.44}$ GeV and $M_{2^{+-}} = 3.07^{+0.25}_{-0.33}$ GeV. We apply the Fierz rearrangement to transform the diquark-antidiquark currents to be the combinations of meson-meson currents, and the obtained Fierz identities indicate that these two states may be searched for in the $P$-wave $\phi(1020) f_0(1710)/\phi(1020) f_2^\prime(1525) (\to \phi K \bar K / \phi \pi \pi)$ channels.Comment: 14 pages, 5 figures, 1 tables, revised version to be published in PR

Low temperature induces two growth-arrested stages and change of secondary metabolites in Bursaphelenchus xylophilus

The third-stage dispersal juvenile (JIII) is the stage for survival and dispersal in the winter of the pine wood nematode, Bursaphelenchus xylophilus. Through investigations at different temperatures, we found two kinds of growth-arrested development, including the adult longevity extension and JIII formation induced by low temperature. They showed similar characters: densely packed lipid droplets and extended longevity. We considered that there were four stages in the formation of growth-arrested stages: induction, growth-arrested pathway, growth-arrested development and cold-tolerance duration. Moreover, at 4◦C there were significant changes in secondary metabolites, which may be related to signal communication and metabolism associated with the formation of growth-arrested stages. The results suggested that low temperature was necessary for the dispersal of pine wood nematode and influenced distribution and intensity of pine wilt

Treatment of osteonecrosis of femoral head with BMSCs-seeded bio-derived bone materials combined with rhBMP-2 in rabbits

ObjectiveTo evaluate the effect of autologous bone marrow mesenchymal stem cells (BMSCs) seeded bio-derived bone materials (BBM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) in repairing defect of osteonecrosis of femoral head (ONFH).MethodsEarly-stage osteonecrosis in the left hip was induced in 36 adult New Zealand white rabbits (provided by the Animal Center of Guangxi Medical University, Nanning, China) after core decompression and delivery of liquid nitrogen into the femoral head. Then the animals were divided into three groups according to the type of implants for bone repair: 12 rabbits with nothing (Group I, the blank control group), 12 with BBM combined with rhBMP-2 (Group II), and 12 with BMSCs-seeded BBM combined with rhBMP-2 (Group III). At 4, 8, and 12 weeks after surgery, X-ray of the femoral head of every 4 rabbits in each group was taken, and then they were killed and the femoral heads were collected at each time point, respectively. Gross observation was made on the femoral heads. After hematoxylin and eosin staining, Lane-sandhu scores of X-ray and bone densitometry were calculated and the histomorphometric measurements were made for the new bone trabeculae.ResultsAt 12 weeks after surgery, two femoral heads collapsed in Group I, but none in Group II or Group III. X-ray examination showed that the femoral heads in Group I had defect shadow or collapsed while those in Group II had a low density and those in Group III presented with a normal density. Histologically, the defects of femoral heads were primarily filled with no new bone but fibrous tissues in Group I. In contrast, new bone regeneration and fibrous tissues occurred in Group II and only new bone regeneration occurrd in Group III. Lane-sandhu scores of X-ray, bone mineral density and rate of new bone in trabecular area in Group III were higher significantly than those of the other two groups.ConclusionsOur findings indicate a superior choice of repairing the experimental defect of ONFH with BMSCs-seeded BBM combined with rhBMP-2