OBJECTIVE: To explore the underlying mechanism of mensenchymal stem cells (MSCs) transfer induced cardiac function improvement in failing hearts. METHODS: Congestive heart failure (CHF) was induced in rats by cauterization of the heart wall. MSCs were cultured from autologous bone marrow and injected into the border zone and the remote myocardium 5 days after cauterization. RESULTS: Ten weeks later, cardiomyocyte nucleus mitotic index, capillary density and expression of insulin-like growth factor 1 (IGF-1), hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) were significantly increased in the border zone and significantly reduced in the remote myocardium in CHF rats (all P<0.05 vs. sham). Besides cardiac function improvement and left ventricular remodeling attenuation evidenced by hemodynamic and echocardiographic examinations, expressions of IGF-1, HGF and VEGF in the remote myocardium and in the border zone were also significantly upregulated (P<0.05 or P<0.01 vs. CHF), and cardiomyocyte nucleus mitotic index as well as capillary density were significantly increased in CHF rats with MSCs (P<0.05 or P<0.01 vs. CHF). Moreover, collagen area was significantly reduced and myocardial area was significantly increased in the border zone in these rats too. CONCLUSION: Autologous MSC implantation upregulated expressions of growth factors enhanced cardioangiogenesis which might be the underlying mechanisms for improved cardiac function and attenuated left ventricular remodeling induced by MSCs transplantation in failing rat myocardium.

Gas-phase methane activation by tungsten (W) atoms was studied at the density functional level of theory using the hybrid exchange correlation functional B3LYP. Four reaction profiles corresponding to the septet, quintet, triplet, and singlet multiplicities were investigated in order to ascertain the presence of some spin inversion during the methane activation. Methane activation mediated by W atoms was found to be a spin-forbidden process resulting from the crossing among the multistate energetic profiles. On the basis of the Hammond postulate, this is a typical two-state reactivity (TSR) reaction. The minimum energy crossing points lead to decrease in the barrier heights of TS01, TS12, TS23, and TS24 that correspond to the first, second, and third hydrogen transfer and the reductive elimination step of H(2), respectively. The spin-orbit coupling is calculated between electronic states of different multiplicities at the crossing points (MECPs) to estimate the intersystem crossing probabilities, and the probability of hopping from one surface to the other in the vicinity of the crossing region is calculated by the Landau-Zener type model.

Chain graphs present a broad class of graphical models for description of conditional independence structures, including both Markov networks and Bayesian networks as special cases. In this paper, we propose a computationally feasible method for the structural learning of chain graphs based on the idea of decomposing the learning problem into a set of smaller scale problems on its decomposed subgraphs. The decomposition requires conditional independencies but does not require the separators to be complete subgraphs. Algorithms for both skeleton recovery and complex arrow orientation are presented. Simulations under a variety of settings demonstrate the competitive performance of our method, especially when the underlying graph is sparse.

Single-crystalline EuF(3) hexagonal microdisks with hollow interior were fabricated to serve as a background-free matrix for analysis of small molecules and polyethylene glycols (PEGs) by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The long-lived excited state of europium ions can transfer energy to high-energy vibrations of organic molecules, which provides the potential technological application in MALDI-TOF-MS analysis of small molecules and PEGs. The efficiency of the hollow microdisks as a novel matrix of low molecular weight compounds was verified by analysis of small peptide, amino acid, organic compounds, and hydroxypropyl beta-cyclodextrin (HP-beta-CD). The advantage of this matrix in comparison with alpha-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB) was demonstrated by MALDI-TOF-MS analysis of an amino acid mixture and a peptide mixture. This matrix is successfully used for analysis of PEGs (PEG 2000, PEG 4000, PEG 8000, PEG 15000, and PEG 30000), suggesting a potential for monitoring reactions and for synthetic polymer quality control. The upper limit of detectable mass range was approximately 35,000 Da (PEG 30000). It is believed that this work will not only offer a new technique for high-speed analysis of small molecules and PEGs but also open a new field for applications of rare earth fluorides.

ABSTRACT: BACKGROUND: All-trans retinoic acid (RA) is one of the most important morphogens with pleiotropic actions. Its embryonic distribution correlates with neural differentiation in the developing central nervous system. To explore the precise effects of RA on neural differentiation of mouse embryonic stem cells (ESCs), we detected expression of RA nuclear receptors and RA-metabolizing enzymes in mouse ESCs and investigated the roles of RA in adherent monolayer culture. RESULTS: Upon addition of RA, cell differentiation was directed rapidly and exclusively into the neural lineage. Conversely, pharmacological interference with RA signaling suppressed this neural differentiation. Inhibition of fibroblast growth factor (FGF) signaling did not suppress significantly neural differentiation in RA-treated cultures. Pharmacological interference with extracellular signal-regulated kinase (ERK) pathway or activation of Wnt pathway effectively blocked the RA-promoted neural specification. ERK phosphorylation was enhanced in RA-treated cultures at the early stage of differentiation. CONCLUSION: RA can promote neural lineage entry by ESCs in adherent monolayer culture systems. This effect depends on RA signaling and its crosstalk with the ERK and Wnt pathways.

Purpose. To investigate the morphology, distribution, and density of inflammatory cells in the corneal epithelium of aqueous tear-deficient dry eye. Methods. Thirty-two patients with non-Sjögren's syndrome dry eye (NSS), 14 patients with Sjögren's syndrome related dry eye (SS), and 33 healthy volunteers were studied. In vivo laser scanning confocal microscopy investigated both Langerhans cell (LCs) and leukocyte, distribution and density in the peripheral and central corneal epithelium. LC morphology was also evaluated. Multi-factor regression analysis assessed if there is a correlation between clinical manifestations and inflammatory cells densities. Results. LCs were present in both central (34.9+/-5.7 cells/mm2) and peripheral (90.7+/-8.2 cells/mm2) parts of the normal corneal epithelium. Moreover, LCs density increased dramatically in the central corneal epithelium in patients with NSS (89.8+/-10.8 cells/mm2 ) and SS (127.9+/-23.7 cells/mm2). The ratio of LCs with obvious processes was much higher in dry eye patients than in healthy volunteers. LCs density also increased in peripheral corneal epithelium in patients with SS, but not NSS. Leukocytes density in normal corneal epithelium was very low, while they increased in the central corneal epithelium (4.6+/-1.0 cells/mm2) in NSS, and in both central (49.0+/-12.9 cells/mm2) and peripheral (84.2+/-36.8 cells/mm2) corneal epithelium in SS. Densities of LCs and leukocytes showed significant correlation with the severity of clinical evaluation. Conclusions: The LCs and leukocyte changes in the corneal epithelium suggest their involvement in aqueous tear-deficient dry eye pathophysiology. In vivo dynamic assessment of central corneal inflammatory cell density might serve as an indicator of dry eye severity and provide new insight for dry eye treatment.

OBJECTIVE: To explore the activation and proliferation of specific T cells induced by artificial antigen-presenting cells (aAPCs) simulated dendritic cells (DCs) and to observed the effect of these T cells on leukemic cell killing. METHODS: aAPCs were developed by coating a human leukocyte antigen-immunoglobulin fusion protein ( HLA-lg), which was connected each one of the four CML28 antigen epitopes (DLMSSTKGL, DLMSSTKGL, ALFCGVACA, VLTFALDSV), and CD28-specific antibody, to magnet-beads CML cell specific peptides (CML28) served as target peptides. Bone marrow (BM) or peripharal blood (PB) mononuclear cells (MNCs) were isolated from HLA-A2 healthy volunteers, and co-cultured with aAPCs. Specific T lymphocyte were detected by flow cytometry. The fresh acute leukemic cells were used as target cells. The specific T cells incubated with leukemic cells for 4 h at ratios of 5:1, 10:1, 20:1, 40:1, 80: 1, respectively. The effect of leukemic cells killing was detected by lactate dehydrogenase release test. RESULTS: The average ratio of CML-28 specific T lymphocyte in control group was (2.2 +/- 0.4)% and in experimental groups (DLMSSTKGL, DLMSSTKGL, ALFCGVACA, VLTFALDSV) were (13.5 +/- 1.6)%,(15.2 +/- 1.5)%,(14.7 +/- 1.8)% and (34.3 +/- 3.5)%, respectively, being significantly higher than that in control group (P < 0.01). Induction efficiencies of acute leukemic cells killing were significantly enhanced by increase of effector cells. The cytotoxic activity of specific T lymphocyte in one experimental group (VLTFALDSV) was much higher than that in other three experimental group (P < 0.05). CONCLUSION: This "prime and expand" regimen should be an alternative method for large scale amplification of rare tumor-specific CTLs and aAPCs might be a useful tool for leukemia immunotherapy.

Orchiectomized (ORX) rats were used to examine the extent to which their increased bone resorption and decreased bone density might relate to increases in RANKL, an essential cytokine for bone resorption. Serum testosterone declined by >95% in ORX rats 1 and 2 weeks after surgery (p<0.05 versus sham controls), with no observed changes in serum RANKL. In contrast, RANKL in bone marrow plasma and bone marrow cell extracts was significantly increased (by ~100%) 1 and 2 weeks after ORX. Regression analyses of ORX and sham controls revealed a significant inverse correlation between testosterone and RANKL levels measured in marrow cell extracts (R=-0.58), while marrow plasma RANKL correlated positively with marrow plasma TRACP-5b, an osteoclast marker (R=0.63). The effects of RANKL inhibition were then studied by treating ORX rats for 6 weeks with OPG-Fc (10 mg/kg, twice/week SC) or with PBS, beginning immediately after surgery. Sham controls were treated with PBS. Vehicle-treated ORX rats showed significant deficits in BMD of the femur/tibia and lower trabecular bone volume in the distal femur (p<0.05 versus sham). OPG-Fc treatment of ORX rats increased femur/tibia BMD and trabecular bone volume to levels that significantly exceeded values for ORX or sham controls. OPG-Fc reduced trabecular osteoclast surfaces in ORX rats by 99%, and OPG-Fc also prevented ORX-related increases in endocortical eroded surface and ORX-related reductions in periosteal bone formation rate. Micro-CT of lumbar vertebrae from OPG-Fc-treated ORX rats demonstrated significantly greater cortical and trabecular bone volume and density versus ORX-vehicle controls. In summary, ORX rats exhibited increased RANKL protein in bone marrow plasma and in bone marrow cells, with no changes in serum RANKL. Data from regression analyses were consistent with a potential role for testosterone in suppressing RANKL production in bone marrow, and also suggested that soluble RANKL in bone marrow might promote bone resorption. RANKL inhibition prevented ORX-related deficits in trabecular BMD, trabecular architecture, and periosteal bone formation while increasing cortical and trabecular bone volume and density. These results support the investigation of RANKL inhibition as a strategy for preventing bone loss associated with androgen ablation or deficiency.

Core-shell structural molecularly imprinted polymer (Cs-MIP) has been successfully prepared by polymerization of MIP on the silica nanospheres surface. The vinyl groups modified on the surface of silica nanospheres have directed the copolymerization of functional monomers and cross linkers in the presence of template molecule, hydroquinone, onto the silica nanospheres surface. The prepared Cs-MIP exhibited fast binding kinetics because the rebinding sites situated at the surface and approximately to the surface of the outer MIP layer. And the Cs-MIP showed higher recognition capacity to hydroquinone than to analogous compounds, such as catechol and resorcinol. An electrochemical sensor fabricated by modifying Cs-MIP on the glassy carbon electrode surface was employed to detect the concentration of hydroquinone with a linear range from 2.0 x 10(-6) to 1.0 x 10(-4) mol/L.

Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe(3)O(4) nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.