707 research outputs found
Perihelion Precession and Deflection of Light in the General Spherically Symmetric Spacetime
The perihelion precession and deflection of light have been investigated
in the 4-dimensional general spherically symmetric spacetime, and the master
equation is obtained. As the application of this master equation, the Reissner-Nordstorm-AdS solution and Clifton-Barrow solution in f(R) gravity have been taken as examples. We find that both the electric charge and f(R) gravity
can affect the perihelion precession and deflection of light, while the cosmological
constant can only effect the perihelion precession. Moreover, we clarify a subtlety
in the deflection of light in the solar system that the possible sun’s electric charge
is usually used to interpret the gap between the experiment data and theoretical
result. However, after also considering the effect from the sun’s same electric charge
on the perihelion precession of Mercury, we can find that it is not the truth
Astragalus polysaccharide relieves reproductive toxicity in phenobarbital-treated epileptic rats
Purpose: To investigate the underlying mechanisms by which Astragalus polysaccharide (APS) relieves the reproductive toxicity induced by phenobarbital (PB) treatment in epileptic rats.Methods: Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay kits were used to quantify cell apoptosis in an epileptic rat model. The weight of sex organs and levels of three reproductive hormones, viz, follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone, were measured in order to evaluate the effect of APS administration on reproductive ability. Concentration, motility, morphology as well as fertilization rate of sperms were analyzed as well.Results: Increase in sex organ weight and decrease in apoptosis were both associated with oral APS treatment. In APS-treated group, FSH, LH, and testosterone levels were raised while concentration, motility and normal morphology of sperm also increased. This was consistent with the observed increase in fertilization rate. In addition, hematoxylin and eosin (HE) staining of the testis was performed in the epileptic rat model showed that the size of cell lumen increased in APS-treated group. All APSassociated phenotypes occurred in a concentration-dependent manner.Conclusion: These data suggest that APS lowers reproductive toxicity in PB-treated epileptic rats by regulating the reproductive hormones, FSH, LH and testosterone, and also by altering the concentration, motility, and morphology of sperm. Thus, APS has a potential treatment for minimizing the side effects of antiepileptic drugs.Keywords: Astragalus polysaccharide, Reproductive toxicity, Phenobarbital, Epileptic rat
Dimension Increase via Hierarchical Hydrogen Bonding from Simple Pincer-like Mononuclear complexes
A tetradentate symmetric ligand bearing both coordination and hydrogen bonding sites, N1,N3-bis(1-(1H-benzimidazol-2-yl)-ethylidene)propane-1,3-diamine (H2bbepd) was utilized to synthesize a series of transition metal complexes, namely [Co(H2bbepd)(H2O)2]·2ClO4
(1), [Cu(H2bbepd)(OTs-)]·OTs- (2),[Cu(bbepd)(CH3OH)] (3), [Cd(H2bbepd)(NO3)2]·CH3OH (4), [Cd(H2bbepd)(CH3OH)Cl]·Cl (5), and
[Cd(bbepd)(CH3OH)2] (6). These complexes show similar discrete pincer-like coordination units, possessing different arrangements of hydrogen bonding donor and acceptor sites. With or without the aid of uncoordinated anions and solvent molecules, such mononuclear
units have been effectively involved in the construction of hierarchical hydrogen bonding assemblies (successively via level I and level II), leading to discrete binuclear ring (complex 2), one-dimensional chain or ribbon (complexes 3, 4 and 6) and
two-dimensional layer (complexes 1 and 5) aggregates
Region- or state-related differences in expression and activation of extracellular signal-regulated kinases (ERKs) in naïve and pain-experiencing rats
<p>Abstract</p> <p>Background</p> <p>Extracellular signal-regulated kinase (ERK), one member of the mitogen-activated protein kinase (MAPK) family, has been suggested to regulate a diverse array of cellular functions, including cell growth, differentiation, survival, as well as neuronal plasticity. Recent evidence indicates a role for ERKs in nociceptive processing in both dorsal root ganglion and spinal cord. However, little literature has been reported to examine the differential distribution and activation of ERK isoforms, ERK1 and ERK2, at different levels of pain-related pathways under both normal and pain states. In the present study, quantitative blot immunolabeling technique was used to determine the spatial and temporal expression of ERK1 and ERK2, as well as their activated forms, in the spinal cord, primary somatosensory cortex (SI area of cortex), and hippocampus under normal, transient pain and persistent pain states.</p> <p>Results</p> <p>In naïve rats, we detected regional differences in total expression of ERK1 and ERK2 across different areas. In the spinal cord, ERK1 was expressed more abundantly than ERK2, while in the SI area of cortex and hippocampus, there was a larger amount of ERK2 than ERK1. Moreover, phosphorylated ERK2 (pERK2), not phosphorylated ERK1 (pERK1), was normally expressed with a high level in the SI area and hippocampus, but both pERK1 and pERK2 were barely detectable in normal spinal cord. Intraplantar saline or bee venom injection, mimicking transient or persistent pain respectively, can equally initiate an intense and long-lasting activation of ERKs in all three areas examined. However, isoform-dependent differences existed among these areas, that is, pERK2 exhibited stronger response than pERK1 in the spinal cord, whereas ERK1 was more remarkably activated than ERK2 in the S1 area and hippocampus.</p> <p>Conclusion</p> <p>Taken these results together, we conclude that: (1) under normal state, while ERK immunoreactivity is broadly distributed in the rat central nervous system in general, the relative abundance of ERK1 and ERK2 differs greatly among specific regions; (2) under pain state, either ERK1 or ERK2 can be effectively phosphorylated with a long-term duration by both transient and persistent pain, but their response patterns differ from each other across distinct regions; (3) The long-lasting ERKs activation induced by bee venom injection is highly correlated with our previous behavioral, electrophysiological, morphological and pharmacological observations, lending further support to the functional importance of ERKs-mediated signaling pathways in the processing of negative consequences of pain associated with sensory, emotional and cognitive dimensions.</p
The G Protein Coupled Receptor 3 Is Involved in cAMP and cGMP Signaling and Maintenance of Meiotic Arrest in Porcine Oocytes
The arrest of meiotic prophase in mammalian oocytes within fully grown follicles is dependent on cyclic adenosine monophosphate (cAMP) regulation. A large part of cAMP is produced by the Gs-linked G-protein-coupled receptor (GPR) pathway. In the present study, we examined whether GPR3 is involved in the maintenance of meiotic arrest in porcine oocytes. Expression and distribution of GPR3 were examined by western blot and immunofluorescence microscopy, respectively. The results showed that GPR3 was expressed at various stages during porcine oocyte maturation. At the germinal vesicle (GV) stage, GPR3 displayed a maximal expression level, and its expression remained stable from pro-metaphase I (MI) to metaphase II (MII). Immunofluorescence staining showed that GPR3 was mainly distributed at the nuclear envelope during the GV stage and localized to the plasma membrane at pro-MI, MI and MII stages. RNA interference (RNAi) was used to knock down the GPR3 expression within oocytes. Injection of small interfering double-stranded RNA (siRNA) targeting GPR3 stimulated meiotic resumption of oocytes. On the other hand, overexpression of GPR3 inhibited meiotic maturation of porcine oocytes, which was caused by increase of cGMP and cAMP levels and inhibition of cyclin B accumulation. Furthermore, incubation of porcine oocytes with the GPR3 ligand sphingosylphosphorylcholine (SPC) inhibited oocyte maturation. We propose that GPR3 is required for maintenance of meiotic arrest in porcine oocytes through pathways involved in the regulation of cAMP and cGMP
The density of macrophages in the invasive front is inversely correlated to liver metastasis in colon cancer
<p>Abstract</p> <p>Background</p> <p>Although an abundance of evidence has indicated that tumor-associated macrophages (TAMs) are associated with a favorable prognosis in patients with colon cancer, it is still unknown how TAMs exert a protective effect. This study examined whether TAMs are involved in hepatic metastasis of colon cancer.</p> <p>Materials and methods</p> <p>One hundred and sixty cases of pathologically-confirmed specimens were obtained from colon carcinoma patients with TNM stage IIIB and IV between January 1997 and July 2004 at the Cancer Center of Sun Yat-Sen University. The density of macrophages in the invasive front (CD68TF<sub>Hotspot</sub>) was scored with an immunohistochemical assay. The relationship between the CD68TF<sub>Hotspot </sub>and the clinicopathologic parameters, the potential of hepatic metastasis, and the 5-year survival rate were analyzed.</p> <p>Results</p> <p>TAMs were associated with the incidence of hepatic metastasis and the 5-year survival rate in patients with colon cancers. Both univariate and multivariate analyses revealed that the CD68TF<sub>Hotspot </sub>was independently prognostic of survival. A higher 5-year survival rate among patients with stage IIIB after radical resection occurred in patients with a higher macrophage infiltration in the invasive front (81.0%) than in those with a lower macrophage infiltration (48.6%). Most importantly, the CD68TF<sub>Hotspot </sub>was associated with both the potential of hepatic metastasis and the interval between colon resection and the occurrence of hepatic metastasis.</p> <p>Conclusion</p> <p>This study showed evidence that TAMs infiltrated in the invasive front are associated with improvement in both hepatic metastasis and overall survival in colon cancer, implying that TAMs have protective potential in colon cancers and might serve as a novel therapeutic target.</p
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