Identifying GSK-3β kinase inhibitors of Alzheimer's disease: Virtual screening, enzyme, and cell assays

Glycogen synthase kinase 3β (GSK-3β) is widely known as a critical target protein for treating Alzheimer's disease (AD). We utilized virtual screening to search databases for compounds with the potential to be used in drugs targeting GSK-3β kinase, and kinase as well as cell assays to investigate top-scored, selected compounds. Virtual screening of >1.1 million compounds in the ZINC and in-house databases was conducted using an optimized computational protocol in the docking program GOLD. Of the top-ranked compounds, 16 underwent a luminescent kinase assay and a cell assay using HEK293 cells expressing DsRed-tagged ΔK280 in the repeat domain of tau (tauRD). The compounds VB-003 (a potent GSK-3β inhibitor) and VB-008 (AM404, an anandamide transport inhibitor), with determined IC50 values of 0.25 and 5.4μM, respectively, were identified as reducing tau aggregation. Both compounds increased expression of phospho-GSK-3β (Ser9) and reduced endogenous tau phosphorylation at the sites of Ser202, Thr231, and Ser396. In the ∆K280 tauRD-DsRed SH-SY5Y cells, VB-008, but not VB-003, enhanced HSPB1 and GRP78 expression, increased ∆K280 tauRD-DsRed solubility, and promoted neurite outgrowth. Thus VB-008 performed best to the end of the present study. The identified compound VB-008 may guide the identification and synthesis of potential inhibitors analogous to this compound.

Compact high-power microwave divider and combiner

A novel, compact, TM01-TE10 mode power divider and a novel, compact, four-way TE10-TM01 mode power combiner were theoretically designed and experimentally tested as a proof of principle. The theoretical and experimental S parameters are consistent with each other. High-power experiments show that their power capacities are no less than 1.5 GW and 3 GW, respectively. The devices have the merits of high power capacities and low insertion losses.

Association between IL2/IL21 and SH2B3 polymorphisms and risk of celiac disease: a meta-analysis

Celiac disease (CD) is a common autoimmune disorder characterized by heightened immunological response to ingested gluten. Certain gene polymorphisms of IL2/IL21 (rs6822844 and rs6840978) and SH2B3 (rs3184504) may influence susceptibility to CD, although the effects remain unclear. We performed a meta-analysis of the associations between rs6822844, rs6840978, and rs3184504 polymorphisms and CD risk. PubMed, EMBASE, and the China National Knowledge Infrastructure were searched. ORs and 95%CIs of each single nucleotide polymorphism (SNP) were estimated using the fixed-effect model if I(2) < 50% in the test of heterogeneity; otherwise, the random-effect model was used. Our meta-analysis included 12,986 CD cases and 28,733 controls from 16 independent samples, and the analysis of each SNP contained a subset of the total. We found that the minor allele T of both rs6822844 (T vs G, OR = 0.72, 95%CI = 0.67-0.78, P < 0.001) and rs6840978 (T vs C, OR = 0.76, 95%CI = 0.71-0.83, P < 0.001) in IL2/IL21 significantly decreased the risk of CD. However, the minor allele A of rs3184504 (A vs G, OR = 1.18, 95%CI = 1.12-1.24, P < 0.001) in SH2B3 significantly increased CD susceptibility. The estimated lambda values were 0.49, 0.50, and 0.53 for rs6822844, rs6840978, and rs3184504, respectively, suggesting that a co-dominant model of genotype effect was most appropriate for the three SNPs. Our results support associations between the three SNPs and CD and provide a strong argument for further research.

Association of TLR2 and TLR4 non-missense single nucleotide polymorphisms with type 2 diabetes risk in a southern Chinese population: a case-control study

Toll-like receptors (TLRs), the triggers of the innate and adaptive immune responses, are involved in the pathogenesis of type 2 diabetes mellitus (T2DM). Several studies have investigated the effects of genetic polymorphisms in TLR4 and TLR2, but they have yielded limited results. We investigated whether non-missense genetic polymorphisms in the regulatory regions of TLR4 and TLR2 were related to T2DM in a southern Chinese population. Single nucleotide polymorphisms (SNPs) in TLR4 (rs1927911, rs11536889, rs1927907, rs1927906, rs1927914, rs7873784, and rs2149356) and TLR2 (rs1898830, rs3804099, rs4696480, and rs3804100) were genotyped in 552 T2DM and 552 unrelated age- and gender-matched controls by SNaPShot Multiplex assay. Genotypes GG (OR = 0.09, 95%CI = 0.01- 0.83, P = 0.03) and CG (OR = 0.08, 95%CI = 0.01-0.74, P = 0.03) of the 3'-untranslated region (UTR) SNP rs7873784 in TLR4, and genotype AG (OR = 0.67, 95%CI = 0.46-0.97, P = 0.04) and allele G (OR = 0.88, 95%CI = 0.79-0.97, P = 0.01) of the intron SNP rs1898830 in TLR2 were identified as protective against the development of T2DM in southern Chinese people. In contrast, a meta-analysis of rs1927911 and rs1927914 showed no association. Haplotypes AGTT (OR = 0.34, 95%CI = 0.15-0.77, P = 0.01) and AATT (OR = 1.20, 95%CI = 1.01- 1.44, P = 0.05) in TLR2 were significantly associated with susceptibility to T2DM. Our results suggest that the effects of non-missense polymorphisms located in the regulatory regions of TLR4 and TLR2 should not be neglected in T2DM association analysis.

Environmental and DNA repair risk factors for breast cancer in South China

PURPOSE

The incidence of breast cancer (BC) in China has been rapidly increasing. We hypothesize that China-specific risk factors, both life-style and inherent ones, contribute to the problem.

METHOD

We have conducted an epidemiology and functional DNA repair investigation to identify risk factors for the development of BC in Shantou, China.

RESULTS

Our survey of 372 patients and 419 matched normal controls confirmed the significant risk from many universal factors: high BMI, low education level, low fruit intake and sedate lifestyle. Significant risk factors can be organized into endogenous ones (low education and cooking with lard instead of vegetable oil) and externally-introduced ones (sedate life-style and cigarette smoking). We also found highly significant risk from passive exposure to cigarette smoke. Using the Challenge-Comet assay and blood samples from 57 patients who did not inherit the tumor suppressor BRCA gene mutations and 62 matched normal controls; we showed that reduced functional DNA repair capacity was a significant risk factor. In addition, the reduced repair capacity was associated with lymph node metastasis, and with tumors that had negative ER receptor and over-expression of Her-2.

CONCLUSION

Our study indicates that combined externally-introduced and endogenous life-style factors were involved with the increased incidence of BC in China. We also showed, for the first time, that inherent deficiency in DNA repair function was a significant risk factor for BC. The inherent deficiency can interact with other risk factors to significantly increase risk for BC. In addition, the reduced repair capacity was associated with certain clinical features that are indicative of poor prognosis. In this context, it is possible to integrate DNA repair capacity knowledge in promoting prevention of BC and in enhancing personalized therapeutic protocols.

High finesse pulsed optical cavity locking by tilt-locking technique

We report the Tilt-Locking (TL) technique applied to lock a laser in pulsed regime to a 28,000 high finesse Fabry-Perot cavity. Preliminary experimental results show that TL technique is comparable with the well-known Pound-Drever-Hall technique. This study is the first to implement the TL technique to lock a pulsed laser to a high-finesse optical cavity. Very high and stable coupling is obtained. The coupling rate is ~80%, and locking can last for more than 1 h. Furthermore, while previously published papers have focused on near field case, in this study we will give the error signal shape simulation for the far field case. We will show that for different types of error sources, the split photodiode transverse position can be carefully adjusted to obtain a symmetrical error signal. Our experimental results are consistent with the simulations.

A simple scheme for injection and extraction in compact rings

There has been great interest in building compact synchrotrons for various applications, for example, inverse Compton scattering X-ray sources. However, the beam injection and extraction in compact rings require careful design for the lack of space. In this paper, we propose a simple combined injection-extraction scheme exploiting the fringe field of existing dipole magnets instead of additional septum magnets. This scheme is illustrated by using the 4.8 m ring proposed for Tsinghua Thomson scattering X-ray source as an example. Particle tracking is applied to demonstrate the validity of this scheme.

Phase-space dynamics of ionization injection in plasma-based accelerators

The evolution of beam phase space in ionization injection into plasma wakefields is studied using theory and particle-in-cell simulations. The injection process involves both longitudinal and transverse phase mixing, leading initially to a rapid emittance growth followed by oscillation, decay, and a slow growth to saturation. An analytic theory for this evolution is presented and verified through particle-in-cell simulations. This theory includes the effects of injection distance (time), acceleration distance, wakefield structure, and nonlinear space charge forces, and it also shows how ultralow emittance beams can be produced using ionization injection methods.

Generating high-brightness electron beams via ionization injection by transverse colliding lasers in a plasma-wakefield accelerator

The production of ultrabright electron bunches using ionization injection triggered by two transversely colliding laser pulses inside a beam-driven plasma wake is examined via three-dimensional particle-in-cell simulations. The relatively low intensity lasers are polarized along the wake axis and overlap with the wake for a very short time. The result is that the residual momentum of the ionized electrons in the transverse plane of the wake is reduced, and the injection is localized along the propagation axis of the wake. This minimizes both the initial thermal emittance and the emittance growth due to transverse phase mixing. Simulations show that ultrashort (~8 fs) high-current (0.4 kA) electron bunches with a normalized emittance of 8.5 and 6 nm in the two planes, respectively, and a brightness of 1.7×10(19) A rad(-2) m(-2) can be obtained for realistic parameters.

Generating ultrabroadband terahertz radiation based on the under-compression mode of velocity bunching

We propose and analyze a scheme to generate enhanced ultrabroadband terahertz (THz) radiation through coherent transition radiation emitted by ultrashort electron beams based on a 10.5 m beamline at Tsinghua University. The proposed scheme involves the initial compression of the electron beam with a few hundred pC charges using a velocity bunching scheme (i.e., RF compression) in an under-compression mode instead of the usual critical-compression mode in order to maintain a positive energy chirp at the exit of the traveling wave accelerator. After a long drift segment, the particles in the tail catch up with the bunch head. More than 80% of the particles are distributed in a spike with an rms length less than 20 fs. Such beams correspond to an ultrabroadband coherent transition radiation (CTR) spectrum of 0.1 THz to 25 THz, with the single-pulse THz radiation energy of up to 50 μJ. The principle of CTR and under-compression mode of velocity bunching are introduced in this paper. And the ASTRA simulation parameters and the stability of the system are also discussed.

Antibiotic prophylaxis for dental procedures: is it necessary?

INTRODUCTION

Guidelines regarding the prevention of infective endocarditis have recently been published by the British Society for Antimicrobial Chemotherapy in 2006, the American Heart Association (AHA) in 2007 and the National Institute for Health and Clinical Excellence (NICE), UK, in 2008. These are contradictory, even though all are from developed countries. It is not known whether they are suitable for developing countries such as South Africa, nor is it known whether they are followed by general dental practitioners.

AIMS AND OBJECTIVES

To conduct a survey amongst dental practitioners in South Africa to determine knowledge of the more recent AHA and NICE guidelines and the practices followed in antibiotic prophylaxis.

METHOD

E-mails were sent to dentists registered with SADA requesting their participation in an internet-based survey.

RESULTS

The limited response rate necessitated the pooling of the data, but it was felt they would be valuable if some trends emerged. Most (88%) of the 105 respondents were aware of the AHA guidelines, but only 55% knew of the NICE guidelines. However, few actually followed the recommendations and few correctly prescribed for patients allergic to penicillin. The large number of cases of rheumatic fever in this country implies that the AHA and NICE guidelines may not be appropriate.

CONCLUSION

Despite the low sample size, the trends shown are of real concern. There is clearly a need for local guidelines, and once these are established, there is an urgent need to inform all dental practitioners of the appropriate prescription of prophylaxis for patients.

A multiscale model for bioimpedance dispersion of liver tissue

Radio-frequency ablation (RFA) has been used in liver surgery to minimize blood loss during tissue division. However, the current RFA tissue division method lacks an effective way of determining the stoppage of blood flow. There is limitation on the current state-of-the-art laser Doppler flow sensor due to its small sensing area. A new technique was proposed to use bioimpedance for blood flow sensing. This paper discusses a new geometrical multiscale model of the liver bioimpedance incorporating blood flow impedance. This model establishes correlation between the physical tissue structure and bioimpedance measurement. The basic Debye structure within a multilevel framework is used in the model to account for bioimpedance dispersion. This dispersion is often explained by the Cole-Cole model that includes a constant phase element without physical explanation. Our model is able to account for reduced blood flow in its output with changes in permittivity in gamma dispersion that is mainly due to the polarization of water molecules. This study demonstrates the potential of a multiscale model in determining the stoppage of blood flow during surgery.

Detection of novel SNPs and mapping of the fatness QTL on pig chromosome 7q1.1-1.4 region

Many QTLs for fatness traits have been mapped on pig chromosome 7q1.1-1.4 in various pig resource populations. Eight novel markers, including seven SNPs and one insertion or deletion within BTNL1, COL21A1, PPARD, GLP1R, MDFI, GNMT, ABCC10, and PLA2G7 genes, as well as two previously reported SNPs in SLC39A7 and HMGA1 genes, were genotyped in Large White and Meishan pig breeds. Except for two SNPs in HMGA1 and ABCC10 genes, allele frequencies of the other eight markers are highly significant different between Chinese indigenous Meishan breeds and Large White pig breeds. Eight polymorphic sites were then used for linkage and QTL mapping to refine the fatness QTL in a Large White × Meishan F(2) resource population. Five chromosome-wise significant QTLs were detected, of which the QTLs for leaf fat weight, backfat thickness at 6-7th rib and rump, and mean backfat thickness were narrowed to the interval between PPARD and GLP1R genes and the QTL for backfat thickness at thorax-waist between GNMT and PLA2G7 genes on SSC7p1.1-q1.4.

Clinical implication of intra-amniotic sludge on ultrasound in patients with cervical cerclage

OBJECTIVE

The aim of this study was to determine whether intra-amniotic (IA) sludge, a sonographic finding of hyperechoic matter in the amniotic fluid close to the internal cervical os, is associated with preterm delivery in patients with cervical cerclage.

METHODS

A retrospective cohort study of patients who had undergone McDonald cerclage between January 1997 and December 2004 was conducted. Transvaginal ultrasound examinations had been performed at 14-28 weeks of gestation, and the ultrasound images were assessed by three reviewers (blinded to patient outcome) to determine the presence or absence of IA sludge. The primary outcome studied was the gestational age at delivery.

RESULTS

A total of 177 patients who had undergone cervical cerclage, and for whom adequate records were available, were identified. Sixty had sonographic evidence of IA sludge (Group 1) and 117 had absence of IA sludge (Group 2). There was no significant difference in the mean gestational age at delivery between the two groups (36.4 ± 4.0 vs. 36.8 ± 2.9 weeks, P = 0.53), and no statistical difference in the rate of preterm delivery at < 28 (6.7% vs. 1.7%, P = 0.18), < 30 (6.7% vs. 3.4%, P = 0.45), < 32 (8.3% vs. 6.8%, P = 0.77) or < 36 (16.7% vs. 19.7%, P = 0.69) weeks of gestation.

CONCLUSION

Intra-amniotic sludge on ultrasound is not associated with an increased risk of preterm delivery in patients with cervical cerclage.

Postischemia myocardial injury in coronary artery bypass patients (PP6)

PURPOSE

To investigate the reperfusion injury of the myocardium in patients undergoing elective coronary artery bypass surgery (CABG) with cardiopulmonary bypass (CPB), we monitored the blood levels of troponin I (TNI), white blood cells, oxygen radicals, malondialdehyde, and myeloperoxidase seeking to define the relationship between the CABG-induced systemic inflammation and myocardial injury.

MATERIALS AND METHODS

We selected 10 patients undergoing primary CABG with CPB at moderate hypothermia and cardioplegic arrest concomitant with intermittent warm blood cardioplegia. We compared all data with their own baseline values to study the reperfusion injury. After release of the aortic clamp, blood was drawn from the coronary sinus, via a catheter placed through the right atrium. We measured plasma levels of inflammatory mediators, such as malondialdehyde, myeloperoxidase, oxygen radicals, and the myocardium injury parameter of TNI.

RESULTS

Patients showed no difference concerning aortic clamp time. TNI increased significantly at 1, 15, and 30 minutes after the onset of reperfusion. Blood levels of white blood cells, oxygen radicals, malondialdehyde, and myeloperoxidase also increased significantly with reperfusion time.

CONCLUSIONS

Reperfusion of ischemic myocardium induced increased TNI, which may be related to the systemic inflammatory responses induced by ischemia and reperfusion of the myocardium among patients undergoing elective coronary bypass surgery.

Strontium borate glass: potential biomaterial for bone regeneration

Boron plays important roles in many life processes including embryogenesis, bone growth and maintenance, immune function and psychomotor skills. Thus, the delivery of boron by the degradation of borate glass is of special interest in biomedical applications. However, the cytotoxicity of borate glass which arises with the rapid release of boron has to be carefully considered. In this study, it was found that the incorporation of strontium into borate glass can not only moderate the rapid release of boron, but also induce the adhesion of osteoblast-like cells, SaOS-2, thus significantly increasing the cyto-compatibility of borate glass. The formation of multilayers of apatite with porous structure indicates that complete degradation is optimistic, and the spread of SaOS-2 covered by apatite to form a sandwich structure may induce bone-like tissue formation at earlier stages. Therefore, such novel strontium-incorporated borosilicate may act as a new generation of biomaterial for bone regeneration, which not only renders boron as a nutritious element for bone health, but also delivers strontium to stimulate formation of new bones.

Two Taiwanese siblings with dyschromatosis universalis hereditaria

Two Taiwanese siblings presented with clinical and histological findings of dyschromatosis universalis hereditaria, which is an uncommon hereditary skin disease. A 26-year-old Taiwanese man had developed diffuse hyperpigmentation with hypopigmented spots over his whole body from the age of 4 years. His 34-year-old brother had also developed a similar skin pigmentary defect from about the same age. Histological examination of the hyperpigmented lesions found an increase in melanin in the basal layer, pigmentary incontinence, and some melanophages in the upper dermis but no increase in the number of melanocytes. The unique clinical, histological, and genetic features of this condition are outlined.

Silver structure environments in ion-exchanged silicate glasses studied by X-ray absorption fine structure

X-ray absorption fine structure (XAFS) technique was used to analyze structural geometry of Ag atoms introduced into soda-lime silicate glass and soda aluminosilicate glass by ion-exchange method. The results show that Ag+ ion in soda aluminosilicate glass takes a coordination number of 1.6 with a Ag-O distance of 2.20 A when the ion-exchange ratio x is smaller than 0.47 and of 2.28 A when x is larger than 0.47. The introduced Ag+ ions are stabilized at the non-bridge oxygen (NBO) sites when x is lower than 0.47. The Na+ ions in AlO4 (O4 represents the bridging oxygen) sites are exchanged by Ag+ ions after all Na+ in NBO sites are replaced. The disorder of Ag-O coordination increases gradually with increasing x from 0.24 to 0.47 in soda aluminosilicate glass and increases dramatically when x is larger than 0.47. Ag+ ions takes a coordination number of 1.6 in the ion-exchanged soda-lime silicate glass and of 1.3 after subsequently thermal treatment with the same Ag-O distance of 2.14 A. Debye-Waller factor (DWF) of Ag-O coordination in soda aluminosilicate glass is higher than that in soda-lime silicate glass. Small Ag cluster has a reduced interatomic distance and a larger DWF. Ag nanoparticle in sample Ag-7 is in a state of tensile stress.

Post-translational modification of delta antigen of hepatitis D virus

The hepatitis delta virus (HDV) genome has only one open reading frame, which encodes the viral small delta antigen. After RNA editing, the same open reading frame is extended 19 amino acids at the carboxyl terminus and encodes the large delta antigen. These two viral proteins escort the HDV genome through different cellular compartments for the complicated phases of replication, transcription and, eventually, the formation of progeny virions. To orchestrate these events, the delta antigens have to take distinct cues to traffic to the right compartments and make correct molecular contacts. In eukaryotes, post-translational modification (PTM) is a major mechanism of dictating the multiple functions of a single protein. Multiple PTMs, including phosphorylation, isoprenylation, acetylation, and methylation, have been identified on hepatitis delta antigens. In this chapter we review these PTMs and discuss their functions in regulating and coordinating the life cycle of HDV.

Prediction of n-octanol/water partition coefficients for polychlorinated dibenzo-p-dioxins using a general regression neural network

A general regression neural network was used for the first time to study quantitative structure and property relationships of organic pollutants to correlate and predict n-octanol/water partition coefficients of polychlorinated dibenzo- p -dioxins from their topological molecular descriptors. In total, 42 polychlorinated dibenzo- p -dioxins and dibenzo- p -dioxins were available for this study-42 polychlorinated dibenzo- p -dioxins and dibenzo- p -dioxins in the training data set and 41 polychlorinated dibenzo- p -dioxins in the test data set. Partial least squares regression, back propagation network and general regression neural network models were trained using the training data set, and the accuracy of the models obtained were examined by the use of leave-one-out cross-validation. For prediction of the n-octanol/water partition coefficient, the best method is the general regression neural network. With the test data set, the correlation coefficient, root mean square error and mean absolute relative error for the general regression neural network model are 0.9276, 0.22 and 2.79%, respectively. For describing the structure of polychlorinated dibenzo- p -dioxins, the topological molecular descriptors outperform the mobile order and disorder thermodynamic method.

The nucleolar phosphoprotein B23 interacts with hepatitis delta antigens and modulates the hepatitis delta virus RNA replication

Hepatitis delta virus (HDV) encodes two isoforms of delta antigens (HDAgs). The small form of HDAg is required for HDV RNA replication, while the large form of HDAg inhibits the viral replication and is required for virion assembly. In this study, we found that the expression of B23, a nucleolar phosphoprotein involved in disparate functions including nuclear transport, cellular proliferation, and ribosome biogenesis, is up-regulated by these two HDAgs. Using in vivo and in vitro experimental approaches, we have demonstrated that both isoforms of HDAg can interact with B23 and their interaction domains were identified as the NH(2)-terminal fragment of each molecule encompassing the nuclear localization signal but not the coiled-coil region of HDAg. Sucrose gradient centrifugation analysis indicated that the majority of small HDAg, but a lesser amount of the large HDAg, co-sedimented with B23 and nucleolin in the large nuclear complex. Transient transfection experiments also indicated that introducing exogenous full-length B23, but not a mutated B23 defective in HDAg binding, enhanced HDV RNA replication. All together, our results reveal that HDAg has two distinct effects on nucleolar B23, up-regulation of its gene expression and the complex formation, which in turn regulates HDV RNA replication. Therefore, this work demonstrates the important role of nucleolar protein in regulating the HDV RNA replication through the complex formation with the key positive regulator being small HDAg.

A method for the fabrication of low-noise carbon fiber nanoelectrodes

A new and facile method has been developed for the fabrication of low-noise carbon fiber microelectrodes (CFMEs) and carbon fiber nanoelectrodes (CFNEs). The carbon fiber was flame-fuse sealed in the tip of the glass capillary. The CFMEs were made by cutting the protruding carbon fiber to the desired length, and the CFNEs were achieved by etching the protruding carbon on the flame to form a nanometer-scale tip. The tip of CFNEs can be controlled within the range from 100 to 300 nm. Thus, no epoxy wax was involved in the CFMEs and CFNEs. The experimental results of inspecting CFMEs and CFNEs by scanning electron microscopy demonstrated that the surface of the electrodes and the glass/fiber interface are very smooth. Therefore, the noise caused by the glass/fiber of these electrodes is much lower than that of the electrodes fabricated conventionlly. The electrodes were characterized by ferricyanide, catecholamine (dopamine,DA), norepinephrine (NE), and epinephrine (E)) and 5-hydroxytryptamine (5-HT) neurotransmitters using CV, LSV, DPV, and FSCV. The results showed that the CFMEs and CFNEs have very excellent electrochemical behavior and high sensitivity. The CV and DPV detection limits of DA, NE, and E are 7.6 x 10(-8), 7.0 x 10(-8), and 5.0 x 10(-8) mol/L, and the DPV detection limits of DA, NE, and E are 4.0 x 10(-8), 1.0 x 10(-7), and 2.2 x 10(-7) mol/L, respectively. This experiment offers a new and facile method for the fabrication of CFMEs and CFNEs of very high sensitivity and low noise.