Estimates of the effects of physical activity on osteoporosis using multivariable Mendelian randomization analysis.

This study estimates causality of physical activity (PA) on bone mineral density (BMD) by conducting multivariable Mendelian randomization (MR). The findings suggest that habitual vigorous PA increases lumbar spine BMD, and higher overall acceleration average would improve forearm BMD. The results could promote PA intervention targeting individuals with optimized type. INTRODUCTION: Evidence from epidemiologic studies showed type, frequency, and duration of PA influenced BMD. However, these observational studies may be confounded by many factors, resulting in spurious associations. We aimed to conduct multivariable MR to estimate the causal effect of self-reported and device-measured PA on osteoporosis. METHODS: Three self-reported and two device-measured PA-related traits were selected as exposures. Outcomes were BMD at different skeletal sites: femoral neck BMD (FN BMD), lumbar spine BMD (LS BMD), and forearm BMD (FA BMD). Exposure datasets were obtained from UK Biobank with total 377,234 subjects. Outcome datasets were obtained from GEFOS consortium with 53,236 subjects. Standard MR analysis and multivariable MR were conducted to assess the total and direct causal effect of PA on BMD. RESULTS: For self-reported PA, inverse-normalized moderate-to-vigorous had a direct causal effect on FN BMD independently (ß = - 1.116 (95% confidence interval, 95%CI: - 2.210, - 0.023), P = 0.045); vigorous PA showed a direct effect (ß = 3.592 (95%CI: 0.310, 6.874), P = 0.032) on LS BMD independently. While overall acceleration average and fraction of accelerations both had a direct causal effect on FA BMD independently. CONCLUSIONS: Habitual vigorous PA could increase LS BMD. Individuals with higher overall acceleration average would have a higher FA BMD.

Detecting causal relationship between metabolic traits and osteoporosis using multivariable Mendelian randomization.

By adopting the extension approaches of Mendelian randomization, we successfully detected and prioritized the potential causal risk factors for BMD traits, which might provide us novel insights for treatment and intervention into bone-related complex traits and diseases. INTRODUCTION: Osteoporosis (OP) is a common metabolic skeletal disease characterized by reduced bone mineral density (BMD). The identified SNPs for BMD can only explain approximately 10% of the variability, and very few causal factors have been identified so far. METHODS: The Mendelian randomization (MR) approach enables us to assess the potential causal effect of a risk factor on the outcome by using genetic IVs. By using extension methods of MR-multivariable MR (mvMR) and MR based on Bayesian model averaging (MR-BMA)-we intend to estimate the causal relationship between fifteen metabolic risk factors for BMD and try to prioritize the most potential causal risk factors for BMD. RESULTS: Our analysis identified three risk factors T2D, FG, and HCadjBMI for FN BMD; four risk factors FI, T2D, HCadjBMI, and WCadjBMI for FA BMD; and three risk factors FI, T2D, and HDL cholesterol for LS BMD, and all risk factors were causally associated with heel BMD except for triglycerides and WCadjBMI. Consistent with the mvMR results, MR-BMA confirmed those risk factors as top risk factors for each BMD trait individually. CONCLUSIONS: By combining MR approaches, we identified the potential causal risk factors for FN, FA, LS, and heel BMD individually and we also prioritized and ranked the potential causal risk factors for BMD, which might provide us novel insights for treatment and intervention into bone-related complex traits and diseases.

[Research advances in the mammalian target of rapamycin signaling pathway and its inhibitors in treatment of hepatocellular carcinoma].

Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase in the downstream of the phosphatidylinositol 3-kinases (PI3K) family. This kinase plays an important role in the development and progression of hepatocellular carcinoma (HCC). Preclinical data demonstrate that 40%-50% of HCC patients have dysregulated expression of the effectors of the mTOR signaling pathway, and the activation of the mTOR pathway is associated with poorly differentiated tumors, early tumor recurrence, and poor survival/prognosis. This article reviews the research advances in the potential role of the mTOR signaling pathway and its inhibitors in the treatment of HCC.

Characterizing and marker-assisting a novel chili pepper (Capsicum annuum L.) yellow bud mutant with cytoplasmic male sterility.

Cytoplasmic male sterility (CMS) in pepper is a better way to produce hybrid seeds compared to manual production. We used the two sequence characterized amplified region (SCAR) markers (CRF-SCAR and CMS-SCAR130) in CMS pepper, to identify the genotype. We assembled two CMS yellow bud mutants (YBM; YBM12-A and YBM12-B). This mutation in leaf color is controlled by a single dominant nuclear gene. The aim was to create a new hybrid seed production method that reduces the costs and increases F1 hybrid seed purity. The results suggest that the CRF-SCAR and CMS-SCAR130 markers can be used together in multiple generations to screen for restorer or maintainer genes. We found the marker linked to the restorer gene (Rf) in the C-line and F1 hybrids, as well as partially in the F2 generation, whereas it was not found in the sterile YBM12-A or the maintainer line YBM12-B. In the F2 population, sterility and fertility segregated at a 3:1 ratio based on the CRF-SCAR marker. A 130 bp fragment was produced in the YBM12-A, F1, and F2 populations, suggesting that these lines contained sterile cytoplasm. A 140 bp fragment present in the YBM12-B and C-line indicated that these lines contained normal cytoplasm. In addition, we identified some morphological characters distinguishing sterile and fertile buds and flowers that may be linked to the sterility gene. If more restorer lines are identified, CMS expressing the YBM trait can be used in hybrid seed production.

Two Dimensional Antiferromagnetic Chern Insulator: NiRuCl6.

Density functional theory (DFT) and Berry curvature calculations show that quantum anomalous Hall effect (QAHE) can be realized in two-dimensional(2D) antiferromagnetic (AFM) NiRuCl6. The results indicate that NiRuCl6 behaves as an AFM Chern insulator and its spin-polarized electronic structure and strong spin-orbit coupling (SOC) are responsible for the QAHE. By tuning SOC, we found that the topological property of NiRuCl6 arises from its energy band inversion. Considering the compatibility between the AFM and insulators, AFM Chern insulator provides a new way to archive high temperature QAHE in experiments due to its different magnetic coupling mechanism from that of ferromagnetic (FM) Chern insulator.

Band gap engineering of early transition-metal-doped anatase TiO2: first principles calculations.

The thermal stability and electronic structures of anatase TiO2 doped with early transition metals (TM) (group III-B = Sc, Y and La; group IV-B = Zr and Hf; group V-B = V, Nb and Ta) have been studied using first principles calculations. It was found that all doped systems are thermodynamically stable, and their band gaps were reduced by 1-1.3 eV compared to pure TiO2. Doping with transition metals affects the strength of the hybrid orbital of TM-O bonding, and the band gap increases approximately linearly with the MP value of TM-O bonding.

Porcine bocaviruses: genetic analysis and prevalence in Chinese swine population.

In members of the Bocavirus genus, that contain three open reading frames (ORFs) of the Parvovirinae subfamily, porcine bocaviruses (PoBoVs) exhibit the most genetic diversity. Based on the ORF2-encoded viral protein (VP1) classification, the six reported porcine bocaviruses were grouped into four species: PoBoV1 (porcine boca-like virus or PBoLV), PoBoV2 (porcine parvovirus 4 or PPV4), PoBoV3 (PBoV1/PBoV2) and PoBoV4 (6V/7V), with PoBoV3 and PoBoV4 each having two genotype viruses. All four PoBoV species were detected in the 166 samples collected in 2010 from swine herds located in ten provinces of China. The detection rates for PoBoV1-4 were 28·9%, 6·6%, 19·3% and 39·7%, respectively. The co-infection combinations involving these six porcine bocaviruses in the collected samples were very complex. Furthermore, mixed infections with viruses from other families (porcine reproductive and respiratory syndrome virus, classic swine fever virus and porcine circovirus type 2) were also detected.

Atomistic origin of lattice strain on stiffness of nanoparticles.

Lattice strain plays a crucial role on the properties of nanoparticles. Although the effect of lattice strain on nanoparticles has been widely studied in experimental measurements and calculations, its physical mechanism from the perfective of bond identities is still poorly understood. Herein we put forward an analytical solution of the size effect and external stimuli such as pressure and temperature dependence of lattice strain and bulk modulus of a nanoparticle from the perspective of atomistic origin. A shell-core configuration has been considered for the nanoparticle structure. It has been found that the lattice strain as well as quantum trapping and energy storage exerted by the compressive stress and thermal stress would be responsible for the mechanical behavior of nanoparticles. The theoretical predictions were well consistent with the experimental data and ab initio calculations, implying that the model could be expected to be a general approach to understand mechanical behavior in nanomaterials.

Systematic review: exosomal microRNAs associated with pancreatic cancer for early detection and prognosis.

OBJECTIVE: Pancreatic cancer (PC) is one of the most common malignant tumors of the digestive system with a high degree of malignancy. Currently, there have been many studies on exosomal microRNAs (miRNAs) discovery in pancreatic cancer. This systematic review aimed to give an overview about known exosomal miRNAs and discuss their diagnostic performance, as well as prognostic value in PC. MATERIALS AND METHODS: PubMed and Web of Science were used for systematic literature research for this review. This literature research was mainly to identify studies that performed plasmatic and serological testing for exosomal miRNAs in pancreatic cancer patients and controls. Two independent reviewers separately extracted data on study characteristics and results. RESULTS: In total, nine prior studies were included in this review. Of which, eleven different single exosomal miRNAs and three exosomal miRNA panels were reported. CONCLUSIONS: When single exosomal miRNA was used as a diagnostic tool, the specificity is generally high, but the sensitivity is commonly low. When multiple of exosomal miRNAs were used simultaneously, higher sensitivities can be obtained at relatively reasonable specificity levels with certain miRNA combinations. Developing a combination of miRNA markers may be a promising approach for early detection of pancreatic cancer.

Energy shifts of Si oxidation states in the system of Si nanocrystals embedded in SiO2 matrix.

Energy shifts in the Si 2p levels of the five Si oxidation states Sin+ (n = 0, 1, 2, 3, 4) in the system of Si nanocrystals embedded in SiO2 matrix have been determined. The thermal annealing effect on the energy shifts has been studied. The result suggests that the Si nanocrystals and the SiO2 are thermally stable but the annealing can cause some structural deformations such as changes in the bond lengths and bond angles for the suboxides Si2O and SiO. The energy shifts generally show a linear dependence on the oxidation state n, suggesting that the energy shifts could be mainly determined by the nearest-neighbor oxygen atoms. It is shown that the chemical structures of the system are similar to those of the conventional SiO2/Si system in terms of the energy shifts.

The role of Notch1 genes in lung cancer A594 cells and the impact on chemosensitivity.

OBJECTIVE: Expression of Notch1 gene in lung cancer A549 cells was reduced using small interfering RNA (small interfering RNA, siRNA) and the effect of Notch1 gene on proliferation and chemo sensitivity of lung cancer A549 cells was studied. MATERIALS AND METHODS: The Notch1 siRNA was transfected into A549 cells by liposome to inhibit the expressions of Notch1 gene in A549 cells. Real-time polymerase chain reaction (RT-PCR) and Western blot were used to detect the expression of Notch1 gene and protein. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method was used to detect the proliferation of A549 cells. After transfection of Notch1-siRNA, cisplatin was added to each group at a concentration of 4 µg/ml, and cultured for 48 h. MTT assay and 4',6-diamidino-2-phenylindole (DAPI) staining was used to evaluate the change of apoptosis and sensitivity to chemotherapy. RESULTS: Notch1 gene expression of A594 cells, detected by RT-PCR and Western blot was significantly reduced in transfected cells when compared with the control group (p<0.05). Inhibition of A594 cell proliferation was significantly decreased as detected by MTT (p<0.05), and the MTT assay and DAPI staining showed that Notch1 gene silencing can significantly improve the sensitivity of A549 cells to chemotherapeutic drugs. CONCLUSIONS: The Notch1 siRNA can effectively inhibit the expression of Notch1 gene, inhibit the proliferation of lung cancer A549 cells and increase the sensitivity to chemotherapeutic drugs.

Modulation of electronic properties from stacking orders and spin-orbit coupling for 3R-type MoS2.

Two-dimensional crystals stacked by van der Waals coupling, such as twisted graphene and coupled graphene-BN layers with unusual phenomena have been a focus of research recently. As a typical representative, with the modulation of structural symmetry, stacking orders and spin-orbit coupling, transitional metal dichalcogenides have shown a lot of fascinating properties. Here we reveal the effect of stacking orders with spin-orbit coupling on the electronic properties of few-layer 3R-type MoS2 by first principles methods. We analyze the splitting of states at the top of valence band and the bottom of conduction band, following the change of stacking order. We find that regardless of stacking orders and layers' number, the spin-up and spin-down channels are evidently separated and can be as a basis for the valley dependent spin polarization. With a model Hamiltonian about the layer's coupling, the band splitting can be effectively analyzed by the coupling parameters. It is found that the stacking sequences, such as abc and abca, have the stronger nearest-neighbor coupling which imply the popular of periodic abc stacking sequence in natural growth of MoS2.

Impedance labelless detection-based polypyrrole protein biosensor.

A simple and sensitive electrochemical immunosensor with impedance labelless detection and novel data processing method was investigated. One-step copolymerization was used to electrochemically deposit an antibody impregnated polypyrrole film on a glassy carbon electrode surface for the immunosensor. Impedance measurements provided a labelless or reporterless method to detect antibody (Ab)-antigen (Ag) interactions. Dimensionless analysis was employed to successfully process the measured impedance data. Since the method derived unit impedance change to eliminate or reduce the variation of the bulk electronic properties of Ab/polypyrrole films, the signal to noise ratio (S/N) was significantly improved for high sensitivity and specificity. Nonspecific binding effect was studied by array electrode chips and was found out that the polypyrrole electrode without antibody attachment had much stronger nonspecific binding effect than the Ab/polypyrrole electrode; incubation followed by thoroughly washing significantly reduced the nonspecific interference. 10 pg/ml detection limit and superior specificity were achieved by the method, demonstrating a highly sensitive labelless immunosensor in comparison with the detection limit of ng -microgram/ml for the reported polypyrrole based immunosensors. The electrochemical immunosensors presented in this paper, due to its simplicity, low cost, high sensitivity and superior specificity, could be an invaluable tool for clinical diagnostics and could have potential applications in drug discovery, environmental and food analysis.

Impedance labelless detection-based polypyrrole DNA biosensor.

Microelectrodes were fabricated to study impedance labelless detection of DNA hybridization. The probe molecule was attached onto the platinum microelectrode surface by electrochemically copolymerizing pyrrole and the probe oligonucleotides. Measured impedance complexes showed that an electrochemical redox-reaction occurred and the electron-transfer resistance increased after DNA hybridization. It was proposed that the hybridization of DNA in the conductive polymer matrix slowed down the anionic doping/undoping process, resulting impedance changes for the target DNA detection. Impedance measurements were conducted at the complementarily hybridized probe oilgomer-attached polypyrrole film electrodes in different anionic solutions to exam the anionic effects. Results showed that higher concentration and smaller size of anions had the lower electron-transfer resistance. The results not only provide further evidence to support the detection mechanism proposed, but also offer a method to improve the signal to noise ratio for the DNA biosensor. The research also tested the specificity of the methods and experimental results, indicating good specificity of the method. A concept array chip was fabricated and used to demonstrate the capability of the labelless detection method. Nano-Molar concentrations were detected and showed fairly linear responses versus the target molecule concentrations. The method is simple and inexpensive. The technique based genosensors could have potential applications in clinical diagnosis, drug discovery, environmental and food analysis.

Synthesis, conformation, and immunosuppressive activity of cyclosporines that contain epsilon-oxygen (4R)-4-[(E)-butenyl]-4,N-dimethyl-L-threonine analogues in the 1-position.

A series of CsA analogues that contain novel epsilon-oxygen isosteres of (4R)-4-[(E)-butenyl]-4,N-dimethyl-L-threonine (MeBmt) in the 1-position were synthesized. The key steps for the syntheses of enantiomerically pure epsilon-oxygen MeBmt analogues 4-7 were based on the stereoselective epoxidation of cis-allylic alcohol derivative 12 with a peracid, followed by the application of a base-catalyzed intramolecular rearrangement of epoxyurethane 15, which was derived from the reaction of epoxy alcohol 14 and methyl isocyanate. All epsilon-oxygen MeBmt analogues have the same stereochemistry and the same functional groups as those on the alpha,beta,gamma-carbons of MeBmt except for the double bond of MeBmt, which is replaced by the -OCH2-group. The syntheses of the peptide portion of CsA analogues followed the strategy we reported previously. The immunosuppressive activities of CsA analogues 28a-e, determined by inhibition of concanavalin A stimulated thymocytes, showed that 28b, which has the closest structural resemblance to MeBmt, retains about 7-10% of activity of CsA, whereas the analogues 28a, 28c, and 28e retain about 2-5% activity. It is interesting to note that 28d, which has the larger benzyl group on the end of the side chain, is about 20-25% as active as CsA. Extensive conformational analyses by 1D and 2D NMR indicated that the conformation of the 33-membered peptide ring system for all CsA analogues was very similar to that of CsA. However, the NMR analyses revealed that the 1-position side chain of all these CsA analogues adopted a novel conformation in chloroform by forming a different intramolecular hydrogen bond between the beta-OH and the epsilon-oxygen of the same residue. The NMR data also suggest that the chloroform conformation of these CsA analogues is similar to the conformation observed in the crystal structure of CsA in that the 1-position side chain is folded across the cyclic peptide ring system.

Synthesis, conformation, and immunosuppressive activities of three analogues of cyclosporin A modified in the 1-position.

The syntheses of three new cyclosporin A (CsA) analogues that contain novel MeBmt derivatives in the 1-position are described. The MeBmt analogue that contains an additional methyl group on C4, (2S,3R,6E)-4,4-dimethyl-3-hydroxy-2-(N-methylamino)-6-octenoic acid (MeBm2t), was synthesized in four steps beginning with the reaction of Pmz-Sar-OtBu with (4E)-2,2-dimethyl-4-hexenal. The C4 desmethyl analogue of MeBmt, (2S,3R,6E)-3-hydroxy-2-(N-methylamino)-6-octenoic acid (MeBth), was synthesized in nine steps by a route based on the Sharpless chiral epoxidation procedure. The alkynyl derivative of MeBmt, (2S,3R,4R)-4-methyl-3-hydroxy-2-(N-methylamino)-6-octynoic acid (MeByt), was synthesized by a modification of the procedure described by Tung et al. for the synthesis of MeBmt. Each MeBmt analogue was protected as the N,O-acetonide and coupled with the hexapeptide Abu-Sar-MeLeu-Val-MeLeu-Ala-OBzl. The resulting heptapeptide was deprotected and coupled with Fmoc-D-Ala-MeLeu-MeLeu-MeVal-OH. The resulting undecapeptides were deprotected and cyclized to give the corresponding CsA analogues. Conformational analysis by 1D and 2D NMR methods was carried out for each analogue in chloroform, and the results are compared with the corresponding solution conformations of CsA and dihydrocyclosporin. The immunosuppressive activities of each analogue, determined in concanavalin A stimulated thymocytes, are lower than obtained for CsA. The results establish the important effect the methyl group and the double bond in MeBmt have on the solution conformation of the 1-position residue in CsA and on immunosuppressive activity.

Synthesis, biological activity, and conformational analysis of (2S,3R,4S)-MeBmt1-cyclosporin, a novel 1-position epimer of cyclosporin A.

Cyclosporin A (CsA, 1), an immunosuppressive cyclic undecapeptide, contains a unique amino acid, (4R)-4-[(E)-butenyl]-4,N-dimethyl-L-threonine (MeBmt), that appears to be critically involved in the biological activity of CsA. In order to further explore the effect that structural elements in MeBmt have on the conformation and biological activity of CsA, the 4-epimer of MeBmt [(4S)-MeBmt, 2] and the corresponding CsA analogue [(4S)-MeBmt1-CsA, 3] have been synthesized. Biological assay using concanavalin A stimulated thymocytes indicated that (4S)-MeBmt1-CsA (3) has only 2-4% immunosuppressive activity relative to CsA. The NMR analysis by 1D and 2D NMR methods establishes the conformation of 3, of which the 33-membered cyclic peptide ring system in chloroform is very similar to that of CsA. However, the NMR analysis also reveals that the 1-position side chain orientation in (4S)-MeBmt1-CsA (3) is very different from that of CsA. Specifically, the (4S)-MeBmt alpha,beta-torsion angle (chi 1) has been rotated approximately 120 degrees relative to that of CsA, and the orientation of the butenyl side chain relative to the 33-membered peptide backbond is different. The orientation of the (4S)-MeBmt side chain is consistent with the possible conformations calculated for (4S)-MeBmt1-CsA (3) by using molecular mechanics (in vacuo) calculations. The conformational analysis suggests that the loss of biological activity for 3 results from an altered conformation of the 1-position side chain relative to the peptide backbond due to the changed chirality at C4 of MeBmt.

New hydroxyethylamine HIV protease inhibitors that suppress viral replication.

The synthesis of analogues of AcSerLeuAsn[Phe-HEA-Pro]IleValOMe (1, JG-365; where HEA stands for the hydroxyethylamine unit 2), a tight-binding inhibitor of HIVP, are reported. Systematic modification of the P3 and P3' regions of the inhibitors has led to smaller HIVP inhibitors that inhibit viral replication in HIV-infected and SIV-infected cell cultures. Six aliphatic and/or aromatic derivatives were prepared by replacing residues in the P3 regions of BocLeuAsn[Phe-HEA-Pro]IleValOMe. Aromatic side chains at P3 gave better inhibitors than aliphatic side chains. The better inhibitors in this series contained a beta-naphthylalanine or a biphenyl unit at P3. A second series of HIVP inhibitors were obtained by converting the P3 group into acyl groups. CbzAsn[Phe-HEA-Pro]IlePheOMe and Qua-Asn-[Phe-HEA-Pro]-Ile-Phe-OMe (where Qua = quinolin-2-ylcarbonyl) are potent HIVP inhibitors with Ki values equal to 1.0 and 0.1 nM, respectively. The inhibition constants were determined by using the continuous fluorometric assay developed by Toth and Marshall. The activities of the protease inhibitors for inhibition of SIV replication were determined in vitro using CEM x 174 cells. Inhibition of HIV infection was determined essentially as reported by Pauwels and co-workers. The anti-HIV assay was carried out in culture using CEM cells (a CD4+ lymphocyte line) infected with virus strain HTLV-IIIb with a multiplicity of infection of 0.1. Several analogues inhibited the cytopathic effect at concentrations of 0.1-0.8 microgram/mL. These results establish that good inhibitors of HIV protease that inhibit viral replication in infected lymphocytes in in vitro cell assays can be obtained from JG-365 when the AcSerLeu unit is replaced by aromatic acyl derivatives.

Dual metalloprotease inhibitors: mercaptoacetyl-based fused heterocyclic dipeptide mimetics as inhibitors of angiotensin-converting enzyme and neutral endopeptidase.

A series of 7,6- and 7,5-fused bicyclic thiazepinones and oxazepinones were generated and incorporated as conformationally restricted dipeptide surrogates in mercaptoacyl dipeptides. These compounds are potent inhibitors of angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP) both in vitro and in vivo. Compound 1a, a 7,6-fused bicyclic thiazepinone, demonstrated excellent blood pressure lowering in a variety of animal models characterized by various levels of plasma renin activity and significantly potentiated urinary sodium, ANP, and cGMP excretion in a cynomolgus monkey assay. On the basis of its potency and duration of action, compound 1a (BMS-186716) was advanced into clinical development for the treatment of hypertension and congestive heart failure.

A novel series of highly potent benzimidazole-based microsomal triglyceride transfer protein inhibitors.

A series of benzimidazole-based analogues of the potent MTP inhibitor BMS-201038 were discovered. Incorporation of an unsubstituted benzimidazole moiety in place of a piperidine group afforded potent inhibitors of MTP in vitro which were weakly active in vivo. Appropriate substitution on the benzimidazole ring, especially with small alkyl groups, led to dramatic increases in potency, both in a cellular assay of apoB secretion and especially in animal models of cholesterol lowering. The most potent in this series, 3g (BMS-212122), was significantly more potent than BMS-201038 in reducing plasma lipids (cholesterol, VLDL/LDL, TG) in both hamsters and cynomolgus monkeys.