Polymorphism in 3'-untranslated region of toll-like receptor 4 gene is associated with protection from hepatitis B virus recurrence after liver transplantation

BACKGROUND

Hepatitis B virus (HBV) recurrence is one of the more severe complications following liver transplantation. Toll-like receptors (TLRs) play a key role in human immunity by recognizing various bacteria, viruses, fungi, and parasites. Single nucleotide polymorphisms (SNPs) in the TLRs are thought to have an impact on the susceptibility to some pathogens. This study focused on the association between polymorphisms in the TLRs and HBV recurrence after liver transplantation in Han Chinese patients.

METHODS

A total of 41 tag SNPs in TLRs were detected by the snapshot technique in 125 patients with primary HBV-related diseases receiving liver transplantation in our center from 2004 to 2008.

RESULTS

By comparing the genetic variations and clinical data between the HBV recurrence patients and nonrecurrence patients, we found that the variant genotype of rs11536889 (TLR4) was significantly associated with HBV recurrence after liver transplantation (P = 0.040, odds ratio was 0.390, 95% confidence interval 0.159-0.957).

CONCLUSION

Our findings indicate that polymorphism in 3'-untranslated regions of the TLR4 gene may be related to protection from HBV recurrence after liver transplantation in Han Chinese patients.

Parametrically excited sectorial oscillation of liquid drops floating in ultrasound

We report experiments in which the nonaxisymmetric sectorial oscillations of water drops have been excited using acoustic levitation and an active modulation method. The observed stable sectorial oscillations are up to the seventh mode. These oscillations are excited by parametric resonance. The oblate initial shape of the water drops is essential to this kind of excitations. The oscillation frequency increases with mode number but decreases with equatorial radius for each mode number. The data can be well described by a modified Rayleigh equation, without the use of additional parameters.

The epidemiology of adolescent acne in North East China

BACKGROUND

Adolescent acne impacts self-esteem and quality of life in adolescents and its aetiology is not fully clarified.

OBJECTIVE

The aim of this study was to describe the epidemiological features of adolescent acne in North East China and determine the impact of genetic and environmental factors on the pathogenesis of acne.

METHODS

Data were collected from 5696 undergraduates (2920 patients and 2776 controls) using questionnaire. The survey data were analysed using spss version 13.0 and heritability of adolescent acne was calculated using Falconer's method.

RESULTS

Total prevalence of adolescent acne was 51.30% (52.74% in males, 49.65% in females). The difference between genders was statistically significant (P < 0.05). Adolescents with a family history of acne had earlier age of onset (P < 0.001). The prevalence of acne in first- and second-degree relatives of acne patients was 22.5% and 7.19%, respectively, significantly higher than in controls (P < 0.001). Heritability of adolescent acne was 78.47 +/- 2.05% in first-degree relatives and 75.05 +/- 3.18% in second-degree relatives. Risk factors to the acne suffers include (in descending order of occurrence), acne family history, mental stress, menstrual disorder, frequent insomnia, high fat diet, being male, dysmenorrhoea, anxiety, sleeping < 8 h per day, depression, fried food, study pressure, spicy food, oily skin and mixed type skin. Protective factors include (presented in descending order of occurrence) dry skin, neutral skin, frequent fruit consumption and computer access time < 2 h daily.

CONCLUSION

Adolescent acne includes a familial genetic predisposition. Additional environmental factors of psychological stress, skin oiliness and high caloric diets may also contribute to the onset of acne in Chinese adolescents.

Viscoelastic properties of silica nanoparticle monolayers at the air-water interface

We have investigated the rheological behaviour of silica nanoparticle layers at the air-water interface. Both compressed and deposited layers have been studied in Langmuir troughs and with a bicone rheometer. The compressed layers are more homogeneous and rigid, and the elastic response to continuous, step and oscillatory compression are similar, provided the compression is fast enough and relaxation is prevented. The deposited layers are less rigid and more viscoelastic. Their shear moduli deduced from the oscillatory uniaxial compression are much smaller than those deduced from pure shear deformation suggesting that the effective shear rate is smaller than expected in the compression measurements.

Electrospun collagen-chitosan nanofiber: a biomimetic extracellular matrix for endothelial cell and smooth muscle cell

Electrospinning of collagen and chitosan blend solutions in a 1,1,1,3,3,3-hexafluoroisopropanol/trifluoroacetic acid (v/v, 90/10) mixture was investigated for the fabrication of a biocompatible and biomimetic nanostructure scaffold in tissue engineering. The morphology of the electrospun collagen-chitosan nanofibers was observed by scanning electron microscopy (SEM) and stabilized by glutaraldehyde (GTA) vapor via crosslinking. Fourier transform infrared spectra analysis showed that the collagen-chitosan nanofibers do not change significantly, except for enhanced stability after crosslinking by GTA vapor. X-ray diffraction analysis implied that both collagen and chitosan molecular chains could not be crystallized in the course of electrospinning and crosslinking, and gave an amorphous structure in the nanofibers. The thermal behavior and mechanical properties of electrospun collagen-chitosan fibers were also studied by differential scanning calorimetry and tensile testing, respectively. To assay the biocompatibility of electrospun fibers, cellular behavior on the nanofibrous scaffolds was also investigated by SEM and methylthiazol tetrazolium testing. The results show that both endothelial cells and smooth muscle cells proliferate well on or within the nanofiber. The results indicate that a collagen-chitosan nanofiber matrix may be a better candidate for tissue engineering in biomedical applications such as scaffolds.

Conduction Properties Of Decellularized Nerve Biomaterials

The purpose of this study is to optimize poly(3,4,-ethylenedioxythiophene) (PEDOT) polymerization into decellular nerve scaffolding for interfacing to peripheral nerves. Our ultimate aim is to permanently implant highly conductive peripheral nerve interfaces between amputee, stump, nerve fascicles and prosthetic electronics. Decellular nerve (DN) scaffolds are an FDA approved biomaterial (Axogen ) with the flexible tensile properties needed for successful permanent coaptation to peripheral nerves. Biocompatible, electroconductive, PEDOT facilitates electrical conduction through PEDOT coated acellular muscle. New electrochemical methods were used to polymerize various PEDOT concentrations into DN scaffolds without the need for a final dehydration step. DN scaffolds were then tested for electrical impedance and charge density. PEDOT coated DN scaffold materials were also implanted as 15-20mm peripheral nerve grafts. Measurement of in-situ nerve conduction immediately followed grafting. DN showed significant improvements in impedance for dehydrated and hydrated, DN, polymerized with moderate and low PEDOT concentrations when they were compared with DN alone (a ≤ 0.05). These measurements were equivalent to those for DN with maximal PEDOT concentrations. In-situ, nerve conduction measurements demonstrated that DN alone is a poor electro-conductor while the addition of PEDOT allows DN scaffold grafts to compare favorably with the "gold standard", autograft (Table 1). Surgical handling characteristics for conductive hydrated PEDOT DN scaffolds were rated 3 (pliable) while the dehydrated models were rated 1 (very stiff) when compared with autograft ratings of 4 (normal). Low concentrations of PEDOT on DN scaffolds provided significant increases in electro active properties which were comparable to the densest PEDOT coatings. DN pliability was closely maintained by continued hydration during PEDOT electrochemical polymerization without compromising electroconductivity.

IFN-gamma triggered STAT1-PKB/AKT signalling pathway influences the function of alloantigen reactive regulatory T cells

CD4+CD25+Foxp3+ regulatory T cells (Tregs) play a key role in the induction and maintenance of peripheral tolerance. Rapid and transient production of IFN-gamma by Tregs from mice tolerized to alloantigen in vivo has been shown to be critical for their regulatory function. This IFN-gamma has the potential to affect the function of cells present in the same local microenvironment as the Tregs, including the Tregs themselves. Here we investigated the mechanism by which IFN-gamma produced by Tregs triggered signaling pathways in alloantigen reactive Tregs themselves thereby influencing their function in vivo. We show that IFN-gamma production and STAT1 activation was increased, while STAT1-dependent PKB/AKT activation was downregulated in alloantigen reactive Tregs. Further, the activation of STAT1 was blocked in IFN-gamma receptor deficient as well as IFN-gamma-deficient Tregs, suggesting that IFN-gamma produced by the alloantigen reactive Tregs might act in an autocrine manner to induce STAT1 activation. Importantly, STAT1-deficient Tregs failed to control allograft rejection in vivo. Overall, these findings suggest that the IFN-gamma-induced STAT1-PKB/AKT signaling pathway plays a key role in upregulating the ability of alloantigen reactive Tregs to control graft rejection in vivo.

Simultaneous pulmonary embolectomy and aortic root replacement

Massive pulmonary embolism (PE) is characterized by hypotension and cardiogenic shock due to right ventricular failure, and is associated with a high mortality rate. In this case study, we report a simultaneous pulmonary embolectomy and aortic root replacement in a 71-year-old woman with a known ascending aortic aneurysm who sustained a massive PE following a VATS left upper lobectomy for non-small cell lung cancer.

Molecular dynamics calculation of thermophysical properties for a highly reactive liquid

In order to further understand the physical characteristics of liquid silicon, the thermophysical properties are required over a broad temperature range. However, its high reactivity brings about great difficulties in the experimental measurement. Here we report the thermophysical properties by molecular dynamics calculation, including density, specific heat, diffusion coefficient, and surface tension. The calculation is performed with a system consisting of 64,000 atoms, and employing the Stillinger-Weber (SW) potential model and the modified embedded atom method (MEAM) potential model. The results show that the density increases as a quadratic function of undercooling, and the value calculated by SW potential model is only 2-4 % smaller than the reported experimental data. The specific heat is obtained to be 30.95 J mol;{-1}K;{-1} by SW potential model and 32.50 J mol;{-1}K;{-1} by MEAM potential model, both of which are constants in the corresponding ranges of temperature. The self-diffusion coefficient is exponentially dependent on the temperature and consistent with the Arrhenius equation. The surface tension increases linearly with the rise of undercooling and agrees well with the reported experimental results. This work provides reasonable data in much wider temperature range, especially for the undercooled metastable state.

Surface tension of liquid ternary Fe-Cu-Mo alloys measured by electromagnetic levitation oscillating drop method

For the liquid Fe-Cu-Mo ternary system, the surface tensions of three selected alloys, i.e., three typical monotectic alloys, were measured by the electromagnetic levitation oscillating drop method over a broad temperature range, including both superheated and undercooled states. The maximum undercooling attained is up to 173 K. The experimental results show a good linear correlation between the surface tension and the temperature. By applying on the Butler equation, the surface tensions were also calculated and they are in good agreement with the measured ones, except that in the undercooled state, the calculated value is slightly larger than the measured results. Interestingly, both the measured and calculated results indicate that the enriched element on the droplet surface is much more conspicuous than other elements in influencing the surface tension. Besides, the viscosity and the density of the liquid Fe-Cu-Mo ternary alloys are also derived on the grounds of the experimentally measured surface tensions.

Combination of short CAG and GGN repeats in the androgen receptor gene is associated with acne risk in North East China

BACKGROUND

Acne vulgaris is one of the most common skin disorders, and androgen is known to play a key role in the development of acne. However, the exact genetic mechanism by which androgen receptor (AR) gene affects acne development is still unclear.

OBJECTIVE

Our study aimed to investigate whether CAG and GGN polymorphism of the AR gene are associated with acne risk.

PATIENTS AND METHODS

Two hundred thirty-eight patients and 207 controls were included in the study. The repeat lengths of the AR gene were determined by GeneScan analysis.

RESULTS

Men with CAG < 23 and women with CAG < 24 had significant risk compared to those men with CAG > or = 23 [odds ratio (OR), 2.07; 95% confidence interval (95% CI), 1.21-3.54] and women with CAG > or = 24 (OR, 2.05; 95% CI, 1.18-3.56). In males, GGN repeats, considered independently of the CAG repeat, have no significant effect on the acne risk; however, when combined with CAG repeats, the acne patients exhibited significantly higher frequency of the haplotypes CAG < 23/GGN < or = 23 (OR, 3.33; 95% CI, 1.10-10.07; P < 0.05) compared with the controls.

CONCLUSION

Our results of this study strongly indicated that a shorter CAG repeat length and specific haplotypes of AR attributed to the risk of acne development and thus could serve as a susceptibility marker.

Study of color-conversion-materials in chromatic-stability white organic light-emitting diodes

We have fabricated high efficiency white organic light-emitting diodes (WOLEDs) with red-dye doped hole injection layer (HIL) and blue emissive layer. We investigated the carrier transport and photoluminescence efficiency in the device of single-layer HIL with different red dye species, bis(4-diphneylamino-phenyl)-perylene-3-yl-amine, 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9enyl)-4Hpyran and a dopant material of fused aromatic ring (P1) provided by Idemitsu Kosan in 4,4',4"-tris[2-naphthyl(phenyl)amino]triphenylamine with a varied concentration. It was found that 25-% wt P1 in HIL has better electro-optical characteristics. Furthermore, we have fabricated three WOLEDs of chromatic-stability with different thickness of HIL layer. High chromatic-stability CCM-WOLEDs have been achieved, which can be applied for lightening and backlight for flat panel display.

A highly color-stability white organic light-emitting diode by color conversion within hole injection layer

We demonstrated a novel-structure white organic light-emitting devices (WOLEDs) composed of a greenish blue fluorescent emitting layer and a red fluorescent dye-doped hole injection layer. The spectra of WOLEDs show no change at a wide range current density operation and long-term continuous operation. We concluded that carriers recombined inside the emitting layer in the WOLEDs to produce a greenish blue electroluminescence (EL), and a part of the EL was absorbed by the red fluorescent guest doped hole injection layer and converted into red photoluminescence (PL); the whole white emission from the device was a mixture of the greenish blue EL and red PL.

Supercooling of aqueous NaCl and KCl solutions under acoustic levitation

The supercooling capability of aqueous NaCl and KCl solutions is investigated at containerless state by using acoustic levitation method. The supercooling of water is obviously enhanced by the alkali metal ions and increases linearly with the augmentation of concentrations. Furthermore, the supercooling depends on the nature of ions and is 2-3 K larger for NaCl solution than that for KCl solution in the present concentration range: Molecular dynamics simulations are performed to reveal the intrinsic correlation between supercoolability and microstructure. The translational and orientational order parameters are applied to quantitatively demonstrate the effect of ionic concentration on the hydrogen-bond network and ice melting point. The disrupted hydrogen-bond structure determines essentially the concentration dependence of supercooling. On the other hand, the introduced acoustic pressure suppresses the increase of supercooling by promoting the growth and coalescence of microbubbles, the effective nucleation catalysts, in water. However, the dissolved ions can weaken this effect, and moreover the degree varies with the ion type. This results in the different supercoolability for NaCl and KCl solutions under the acoustic levitation conditions.

TIMP-2 upregulates RECK expression via dephosphorylation of paxillin tyrosine residues 31 and 118

We previously demonstrated that TIMP-2 increases the association of Crk with C3G and via subsequent activation of Rap1 enhances the expression of RECK, a membrane-anchored MMP inhibitor. In the present study, we investigate the mechanism of how the TIMP-2 signal is transduced from the alpha3beta1 integrin receptor to the Crk-C3G-Rap1 molecular complex. TIMP-2 treatment of human microvascular endothelial cells (hMVECs) increased the phosphorylation levels of Src at Tyr-527, the negative regulatory site, through enhanced association of Src with Csk. This results in the reduction of Src kinase activity and dephosphorylation of paxillin at Tyr-31/118, the target sites for Src kinase phosphorylation and also the binding sites for the downstream effector Crk. Such TIMP-2 effects accompany the disassembly of paxillin-Crk-DOCK180 molecular complex and, in turn, Rac1 inactivation. On the contrary, levels of paxillin-Crk-C3G complex formation are not reduced, rather slightly increased, which is consistent with our previous finding. Therefore, TIMP-2-mediated inhibition of Src kinase activity leads to the signaling switch from Rac1 to Rap1, thereby leading to enhanced RECK expression.

The characteristics of tolerogenic plasmacytoid dendritic cells stimulated with interleukin-3

This study focused on whether bone marrow would differentiate tolerogenic dendritic cells (DCs) by comparing interleukin-3 (IL-3) DCs (induced by IL-3+IL-4) with GM-CSF DCs (induced by GM-CSF+IL-4, generating myeloid DCs). Mouse bone marrow progenitors were induced in vitro to differentiate into DCs by exposure to IL-3. The morphology and yields of IL-3 DCs and GM-CSF DCs were compared by scanning electron microscopy and laser scanning confocal microscopy. Immunohistochemistry and flow cytometer (FCM) were used to identify immune phenotypes. The results showed that IL-3 DCs and GM-CSF DCs both expressed the specific marker DEC-205 with about 80% and 70% purity, respectively. IL-3 DCs had similar morphology as plasma cells, but a different immune phenotype, namely, CD80(-), CD86(-), CD14(-), and MHC class II(+). IL-3 DCs remained in the costimulatory molecule-deficient state when TNF-alpha was supplemented into the culture. We therefore propose that IL-3 induces a high purity and yield of DCs from bone marrow. Since IL-3 DCs possess a tolerogenic phenotype (MHC class II(+), B7(-)), they may induce alloantigen-specific hyporesponsiveness in vitro.

Stable Transformation of CHO Cells and Human NARP Cybrids Confers Oligomycin Resistance (olir) Following Transfer of a Mitochondrial DNA–Encoded olirATPase6 Gene to the Nuclear Genome: A Model System for mtDNA Gene Therapy

Point and deletion mutations and a general depletion of mammalian mitochondrial DNA (mtDNA) give rise to a wide variety of medical syndromes that are refractory to treatment, possibly including aging itself. While gene therapy directed at correcting such deficits in the mitochondrial genome may offer some therapeutic benefits, there are inherent problems associated with a direct approach. These problems are primarily due to the high mitochondrial genome copy number in each cell and the mitochondrial genome being "protected" inside the double-membrane mitochondrial organelle. In an alternative approach there is evidence that genes normally present in the mitochondrial genome can be incorporated into the nuclear genome. To extend such studies, we modified the Chinese Hamster Ovary (CHO) mtDNA-located ATPase6 gene (possessing a mutation which confers oligomycin resistance- oli(r)) by altering the mtDNA code to the universal code (U-code) to permit the correct translation of its mRNA in the cytoplasm. The U-code construct was inserted into the nuclear genome (nucDNA) of a wild type CHO cell. The expressed transgene products enabled the transformed CHO cell lines to grow in up to 1000 ng mL(-1) oligomycin, while untransformed sensitive CHO cells were eliminated in 1 ng mL(-1) oligomycin. This approach, termed allotopic expression, provides a model that may make possible the transfer of all 13 mtDNA mammalian protein-encoding genes to the nucDNA, for treatments of mtDNA disorders. The CHO mtATPase6 protein is 85% identical to both the mouse and human mtATPase6 protein; these proteins are highly conserved in the region of the oligomycin resistance mutation. They are also well conserved in the regions of the oligomycin resistance mutation of the mouse, and in the region of a mutation found in Leigh's syndrome (T8993G), also called NARP (neurogenic weakness, ataxia, retinitis pigmentosum). It is likely that the CHO oli(r) mtATPase6 Ucode construct could impart oligomycin-resistance in human and mouse cells, as well as function in place of the mutant ATPase subunit in a NARP cell line. Preliminary experiments on human cybrids homoplasmic for the NARP mutation (kindly supplied by D.C. Wallace), transformed with our construct, display an increased oligomycin resistance that supports these suppositions.

Dynamics of acoustically levitated disk samples

The acoustic levitation force on disk samples and the dynamics of large water drops in a planar standing wave are studied by solving the acoustic scattering problem through incorporating the boundary element method. The dependence of levitation force amplitude on the equivalent radius R of disks deviates seriously from the R3 law predicted by King's theory, and a larger force can be obtained for thin disks. When the disk aspect ratio gamma is larger than a critical value gamma(*) ( approximately 1.9 ) and the disk radius a is smaller than the critical value a(*) (gamma) , the levitation force per unit volume of the sample will increase with the enlargement of the disk. The acoustic levitation force on thin-disk samples ( gamma</= gamma(*) ) can be formulated by the shape factor f(gamma,a) when a</= a(*) (gamma) . It is found experimentally that a necessary condition of the acoustic field for stable levitation of a large water drop is to adjust the reflector-emitter interval H slightly above the resonant interval H(n) . The simulation shows that the drop is flattened and the central parts of its top and bottom surface become concave with the increase of sound pressure level, which agrees with the experimental observation. The main frequencies of the shape oscillation under different sound pressures are slightly larger than the Rayleigh frequency because of the large shape deformation. The simulated translational frequencies of the vertical vibration under normal gravity condition agree with the theoretical analysis.

Removal of fluoride from water by carbon nanotube supported alumina

This paper describes a new adsorption material carbon nanotube supported alumina, used for fluoride removal from water. The effects of calcination temperature, alumina loading and pH on fluoride removal capacity were investigated. The optimum calcination temperature for preparing the adsorbents is 450 degrees C and the largest adsorption capacity takes place at alumina loading of 30 wt%. The broad pH range of 6.0-9.0 with high adsorption capability suggests that carbon nanotube supported alumina have great potential applications in practice. The adsorption data at different pH were well fitted to the Freundlich isotherm. The kinetic studies show that the adsorption reaction of fluoride removal by carbon nanotube supported alumina can be described by a second orderrate equation.

Eutectic growth under acoustic levitation conditions

Samples of Pb-Sn eutectic alloy with a high density of 8.5 x 10(3) kg/m(3) are levitated with a single-axis acoustic levitator, and containerlessly melted and then solidified in argon atmosphere. High undercoolings up to 38 K are obtained, which results in a microstructural transition of "lamellas-broken lamellas-dendrites." This transition is further investigated in the light of the coupled zone for eutectic growth and the effects of ultrasound. The breaking of regular eutectic lamellas and suppression of gravity-induced macrosegregation of (Pb) and (Sn) dendrites are explained by the complicated internal flow inside the levitated drop, which is jointly induced by the shape oscillation, bulk vibration and rotation of the levitated drop. The ultrasonic field is also found to drive forced surface vibration, which subsequently excites capillary ripples and catalyzes nucleation on the sample surface.

Levitation of iridium and liquid mercury by ultrasound

Single-axis acoustic levitation of the heaviest solid (iridium, rho=22.6 g cm(-3)) and liquid (mercury, rho=13.6 g cm(-3) on the Earth is achieved by greatly enhancing both the levitation force and stability through optimizing the geometric parameters of the levitator. The acoustically levitated Pb-Sn eutectic alloy melt (rho=8.5 g cm(-3)) is highly undercooled by up to 38 K, which results in a microstructural transition of "lamellae-broken lamellae-dendrites." The drastic enhancement of levitation capability indicates a broader application range of single-axis acoustic levitation.

Dependence of acoustic levitation capabilities on geometric parameters

A two-cylinder model incorporating boundary element method simulations is developed, which builds up the relationship between the levitation capabilities and the geometric parameters of a single-axis acoustic levitator with reference to wavelength. This model proves to be successful in predicting resonant modes of the acoustic field and explaining axial symmetry deviation of the levitated samples near the reflector and emitter. Concave reflecting surfaces of a spherical cap, a paraboloid, and a hyperboloid of revolution are investigated systematically with regard to the dependence of the levitation force on the section radius R(b) and curvature radius R (or depth D) of the reflector. It is found that the levitation force can be remarkably enhanced by choosing an optimum value of R or D, and the possible degree of this enhancement for spherically curved reflectors is the largest. The degree of levitation force enhancement by this means can also be facilitated by enlarging R(b) and employing a lower resonant mode. The deviation of the sample near the reflector is found likely to occur in case of smaller R(b), larger D, and a higher resonant mode. The calculated dependence of levitation force on R, R(b), and the resonant mode is also verified by experiment and finally demonstrated to be in good agreement with experimental results, in which considerably a strong levitation force is achieved to levitate an iridium sphere which has the largest density of 22.6 g/cm(3).