High-performance transparent solvent-free silicone resins with stable storage and low viscosity based on new hyperbranched polysiloxanes

Five new hyperbranched polysiloxanes, for example, methylhydrogen siloxanes (MHSis), with varying concentrations of silicon–methyl (Si-Me) groups were synthesized and characterized, and then a series of MHSi/poly(methylphenylvinylsilicone) (PSi) resins were prepared to investigate the influence of the structures and concentrations of MHSi on the integrated properties of both uncured and cured MHSi/PSi resins. The results show that the compatibility between MHSi and PSi is closely related to the concentration of Si-Me groups in the MHSi as well as the molar ratio of MHSi and PSi. If MHSi has a suitable concentration of Si-Me groups, and the molar ratios of MHSi to PSi are appropriate, transparent MHSi/PSi resins with stable compatibility can be obtained. In addition, these compatible resins show good thermal stability with dynamic mechanical and dielectric properties. They exhibit a great potential for use as high-performance solvent-free silicone resins in either vacuum pressure impregnating process or liquid-molding techniques.

Nucleosome occupancy and gene regulation during tumorigenesis

Nucleosomes are the basic structural units of eukaryotic chromatin. In recent years, it has become evident that nucleosomes and their position, in concert with other epigenetic mechanisms (such as DNA methylation, histone modifications, changes in histone variants, as well as small noncoding regulatory RNAs) play essential roles in the control of gene expression. Here, we discuss the mechanisms and factors that regulate nucleosome position and gene expression in normal and cancer cells.

miR-30d, miR-181a and miR-199a-5p cooperatively suppress the endoplasmic reticulum chaperone and signaling regulator GRP78 in cancer

GRP78, a major endoplasmic reticulum chaperone and signaling regulator, is commonly overexpressed in cancer. Moreover, induction of GRP78 by a variety of anti-cancer drugs, including histone deacetylase inhibitors, confers chemoresistance to cancer, thereby contributing to tumorigenesis. Thus, therapies aimed at decreasing GRP78 levels, which results in the inhibition of tumor cell proliferation and resensitization of tumor cells to chemotherapeutic drugs may hold promise for cancer treatment. Despite advances in our understanding of GRP78 actions, little is known about endogenous inhibitors controlling its expression. As endogenous regulators, microRNAs (miRNAs) play important roles in modulating gene expression; therefore, we sought to identify miRNA(s) that target GRP78, under the hypothesis that these miRNAs may serve as therapeutic agents. Here, we report that three miRNAs (miR-30d, miR-181a, miR-199a-5p) predicted to target GRP78 are down-regulated in prostate, colon and bladder tumors, and human cancer cell lines. We show that in C42B prostate cancer cells, these miRNAs down-regulate GRP78 and induce apoptosis by directly targeting its 3' untranslated region. Importantly, we demonstrate that the three miRNAs act cooperatively to decrease GRP78 levels, suggesting that multiple miRNAs may be required to efficiently control the expression of some genes. In addition, delivery of multiple miRNAs by either transient transfection or lentivirus transduction increased the sensitivity of cancer cells to the histone deacetylase inhibitor, trichostatin A, in C42B, HCT116 and HL-60 cells. Together, our results indicate that the delivery of co-transcribed miRNAs can efficiently suppress GRP78 levels and GRP78-mediated chemoresistance, and suggest that this strategy holds therapeutic potential.

High dose compressive loads attenuate bone mineral loss in humans with spinal cord injury

People with spinal cord injury (SCI) lose bone and muscle integrity after their injury. Early doses of stress, applied through electrically induced muscle contractions, preserved bone density at high-risk sites. Appropriately prescribed stress early after the injury may be an important consideration to prevent bone loss after SCI.

INTRODUCTION

Skeletal muscle force can deliver high compressive loads to bones of people with spinal cord injury (SCI). The effective osteogenic dose of load for the distal femur, a chief site of fracture, is unknown. The purpose of this study is to compare three doses of bone compressive loads at the distal femur in individuals with complete SCI who receive a novel stand training intervention.

METHODS

Seven participants performed unilateral quadriceps stimulation in supported stance [150% body weight (BW) compressive load-"High Dose" while opposite leg received 40% BW-"Low Dose"]. Five participants stood passively without applying quadriceps electrical stimulation to either leg (40% BW load-"Low Dose"). Fifteen participants performed no standing (0% BW load-"Untrained") and 14 individuals without SCI provided normative data. Participants underwent bone mineral density (BMD) assessment between one and six times over a 3-year training protocol.

RESULTS

BMD for the High Dose group significantly exceeded BMD for both the Low Dose and the Untrained groups (p < 0.05). No significant difference existed between the Low Dose and Untrained groups (p > 0.05), indicating that BMD for participants performing passive stance did not differ from individuals who performed no standing. High-resolution CT imaging of one High Dose participant revealed 86% higher BMD and 67% higher trabecular width in the High Dose limb.

CONCLUSION

Over 3 years of training, 150% BW compressive load in upright stance significantly attenuated BMD decline when compared to passive standing or to no standing. High-resolution CT indicated that trabecular architecture was preserved by the 150% BW dose of load.

CD40L demethylation in CD4(+) T cells from women with rheumatoid arthritis

We have previously demonstrated that DNA demethylation of CD40L on the X chromosome is responsible for female susceptibility to systemic lupus erythematosus (SLE). It is unknown whether aberrant methylation of the CD40L gene also contributes to the higher incidence of rheumatoid arthritis (RA) in females. In this study, we used real-time RT-PCR and flow cytometry to compare CD40L expression levels, and bisulfite sequencing to assess the methylation status of the CD40L promoter region. The results show that CD40L is upregrulated in CD4(+) T cells of female patients with RA. In addition, the CD40L promoter region in CD4(+) T cells from female RA patients was found to be demethylated, which corresponded with increased CD40L mRNA expression. These findings suggest that DNA demethylation contributes to CD40L expression in RA CD4(+) T cells and may in part explain the female preponderance of this disease.

Demethylation of the FCER1G promoter leads to FcεRI overexpression on monocytes of patients with atopic dermatitis

BACKGROUND

Overexpression of the high-affinity receptor for immunoglobulin E on atopic monocytes and dendritic cells is known to contribute to the pathogenesis of atopic dermatitis (AD). However, it remains unclear what is the underlying mechanism of FcεRI deregulation. It has been speculated that epigenetic deregulation may play a role.

METHODS

Global DNA methylation levels of monocytes from 10 AD patients and 10 healthy controls were measured using a global DNA methylation kit. Bisulfite sequencing was performed to determine the methylation status of the FCER1G promoter region. FcεRIγ mRNA and FcεRI protein levels were detected by real-time RT-PCR, Western blotting, and flow cytometry, respectively. Patch methylation and the demethylating agent, 5-azacytidine, were used to determine the functional significance of methylation changes on FcεRI expression.

RESULTS

Monocytes from AD patients show a global hypomethylation, as well as a locus-specific hypomethylation at FCER1G promoter, as compared to healthy controls. Furthermore, this hypomethylation of FCER1G is inversely correlated with its expression. Patch methylation in combination with luciferase reporter assay confirmed the direct relationship between methylation and expression. Moreover, treating healthy monocytes with 5-azacytidine caused a reduction in methylation levels and an induction in FcεRIγ transcription and surface expression of FcεRI.

CONCLUSION

Demethylation of specific regulatory elements within the FCER1G locus contributes to FcεRI overexpression on monocytes from patients with AD.

Abnormal epigenetic modifications in peripheral blood mononuclear cells from patients with alopecia areata

BACKGROUND

Alopecia areata (AA) is a hair loss disease caused by T-cell-mediated autoimmune reactions against anagen-stage hair follicles. Although the exact aetiology is poorly understood, there is evidence to suggest that both genetic and environmental factors are involved in AA pathogenesis.

OBJECTIVES

To analyse DNA methylation and histone modification patterns in peripheral blood mononuclear cells (PBMCs) of patients with AA.

METHODS

PBMC samples were obtained from 25 patients with AA and 20 healthy controls. Global DNA methylcytosine levels, as well as histone acetylation and methylation levels, were measured by enzyme-linked immunosorbent assay. mRNA expression levels were determined using real-time quantitative reverse transcription-polymerase chain reaction.

RESULTS

Genomic DNA methylation in PBMCs of patients with AA was increased relative to controls. DNMT1, MBD1 and MBD4 expression levels were significantly higher in AA PBMCs than in controls, and DNMT1 transcription levels positively correlated with global DNA methylation levels in patient samples. Histone H3 acetylation was significantly increased and histone H3 lysine 4 methylation was significantly decreased in patient PBMCs compared with healthy controls. Histone H3 acetylation levels were positively correlated with AA disease severity, and with RANTES (CCL5) mRNA expression in PBMCs of patients with AA. These changes were accompanied by increased p300 (EP300), histone deacetylase 1 (HDAC1), myeloid/lymphoid or mixed lineage leukemia (MLL), SET7/9 (SETD7), G9A (EHMT2), JMJD2C (KDM4C) and JARID1A (KDM5A) expression, as well as reduced HDAC2, HDAC7, LSD1 (KDM1A), JMJD2A (KDM4A) and JMJD2B (KDM4B) expression.

CONCLUSIONS

DNA methylation and histone modification status are altered in PBMCs of patients with AA, possibly due to the deregulation of epigenetic regulatory genes. These changes may contribute to the activation of pathological immune responses in AA.

Surviving starvation: essential role of the ghrelin-growth hormone axis

After brief starvation, vertebrates maintain blood glucose by releasing fatty acids from adipose tissue. The fatty acids provide energy for gluconeogenesis in liver and are taken up by muscle, sparing glucose. After prolonged starvation, fat stores are depleted, yet blood glucose can be maintained at levels sufficient to preserve life. Using a new mouse model, we demonstrate that survival after prolonged starvation requires ghrelin, an octanoylated peptide hormone that stimulates growth hormone (GH) secretion. We studied wild-type mice and mice lacking ghrelin as a result of knockout of GOAT, the enzyme that attaches octanoate to ghrelin. Mice were fed 40% of their normal intake for 7 d. Fat stores in both lines of mice became depleted after 4 d. On day 7, mice were fasted for 23 h. In wild-type mice, ghrelin and GH rose massively, and blood sugar was maintained at ~60 mg/dL. In Goat(-/-) mice, ghrelin was undetectable and GH failed to rise appropriately. Blood sugar declined to ~20 mg/dL, and the animals were moribund. Infusion of ghrelin or GH prevented hypoglycemia. Our results support the following sequence: (1) Starvation lowers blood glucose; (2) glucose-sensing neurons respond by activating sympathetic neurons; (3) norepinephrine, released in the stomach, stimulates ghrelin secretion; (4) ghrelin releases GH, which maintains blood glucose. Thus, ghrelin lies at the center of a hormonal response that permits mice to survive an acute fast superimposed on chronic starvation.

Health risk assessment of organochlorine contaminants in fish from a major lake (Baiyangdian Lake) in North China

Organochlorine contaminants (OCs) in fish were determined to evaluate the potential risk to humans consuming fish originating in Baiyangdian Lake, North China. Relatively low levels of PCBs, HCHs and DDTs were observed, with mean concentrations ranging from 0.28 to 3.28 ng/g, wet weight. Among various fish species tested, the highest burden of OCs was recorded in northern snakehead (7.39 ng/g, wet weight) and the lowest was in grass carp (2.04 ng/g, wet weight). The hazard ratios (HRs), based on noncancer risk were all less than 1.0, while the HRs based on cancer risk exceeded 1.0 only for PCBs based on the 90th percentile concentration.

A new osteophyte segmentation algorithm using partial shape model and its applications to rabbit femur anterior cruciate ligament transection via micro-CT imaging

Osteophyte is an additional bony growth on a normal bone surface limiting or stopping motion at a deteriorating joint. Detection and quantification of osteophytes from CT images is helpful in assessing disease status as well as treatment and surgery planning. However, it is difficult to distinguish between osteophytes and healthy bones using simple thresholding or edge/texture features due to the similarity of their material composition. In this paper, we present a new method primarily based active shape model (ASM) to solve this problem and evaluate its application to anterior cruciate ligament transection (ACLT) rabbit femur model via CT imaging. The common idea behind most ASM based segmentation methods is to first build a parametric shape model from a training dataset and apply the model to find a shape instance in a target image. A common challenge with such approaches is that a diseased bone shape is significantly altered at regions with osteophyte deposition misguiding an ASM method and eventually leading to suboptimum segmentations. This difficulty is overcome using a new partial ASM method that uses bone shape over healthy regions and extrapolates it over the diseased region according to the underlying shape model. Finally, osteophytes are segmented by subtracting partial-ASM derived shape from the overall diseased shape. Also, a new semi-automatic method is presented in this paper for efficiently building a 3D shape model for an anatomic region using manual reference of a few anatomically defined fiducial landmarks that are highly reproducible on individuals. Accuracy of the method has been examined on simulated phantoms while reproducibility and sensitivity have been evaluated on CT images of 2-, 4- and 8-week post-ACLT and sham-treated rabbit femurs. Experimental results have shown that the method is highly accurate ( R2 = 0.99), reproducible (ICC = 0.97), and sensitive in detecting disease progression (p-values: 0.065,0.001 and < 0.001 for 2- vs. 4, 4- vs. 8- and 2- vs. 8-weeks, respectively).

Stent-assisted coil embolization of wide-necked intracranial aneurysms using a semi-deployment technique: angiographic and clinical outcomes in 31 consecutive patients

We describe a modified stent-assisted coiling technique, named the semi-deployment technique, in the endovascular treatment of wide-neck aneurysms. Thirty-one consecutive patients with 31 wide-necked or fusiform intracranial aneurysms were treated with the semi-deployment technique. The technical feasibility of the procedure, procedure-related complications, angiographic results, clinical outcome and follow-up angiography were evaluated. In every case, the semi-deployment technique was successfully deployed. Immediate angiography demonstrated complete occlusion in 24 cases (77.4%), neck remnant in four cases (12.9%), and incomplete occlusion in three cases (9.7%). Procedural-related morbidity occurred in one patient (3.2%) but no procedural-related mortality. A favorable clinical outcome (Modified Ran-kin Scale score 0-2) was observed in 90.3% of the patients (average follow-up time, 23.1 months). No rehemorrhage of treated aneurysms occurred. Angiography follow-up was obtained in 22 cases (71.0 %). Three aneurysms (13.6 % of the follow-up angiograms) demonstrated recanalization. No delayed coil or stent migration was found. One patient had in-stent stenosis as a delayed complication. We found that the semi-deployment technique was helpful in the treatment of wide-neck aneurysms.

C nuclear magnetic resonance study of five- and six-coordinated carbon in nonclassical organometallic compounds: Dimeric trialkyl-, tricyclopropyl-, and triarylaluminums and some nido and closo carboranes

A (13)C nuclear magnetic resonance spectroscopic study of dimeric trimethyl-, triethyl-, tricyclopropyl-, and triarylaluminums is reported. The five-coordinated bridging carbons are found consistently more shielded than the terminal carbons, in accordance with the increased p-character of the former. The nature of bridging two-electron three-centered Al-C-Al bonds is discussed. (13)C nuclear magnetic resonance shifts of several nido and closo carboranes containing five and six coordinated carbons and their (13)C-(1)H spin-spin coupling constants were also obtained. The relationship between the carbon chemical shifts and coordination number of the carbon atom is discussed. There is approximately a 20- to 40-ppm shielding of the (13)C chemical shifts of five- and six-coordinated carbons, compared with those of four valent carbons, with a simultaneous general increase of J(C-H) coupling constants.

Cloning and sequencing of adhesion protein gene of Trichomonas gallinae from pigeon

The adhesion protein (AP) gene of Trichomonas gallinae from pigeon was cloned and sequenced. The first-strand cDNA of the AP gene of T. gallinae from pigeon was amplified by reverse transcription polymerase chain reaction (RT-PCR) with total RNA extracting kit and cloned in the vector pMD18-T. The recombinant plasmid was identified by PCR and restriction endonuclease, and the positive clone was sequenced and analysed by comparing the sequence similarity with other sequences in the GenBank. The AP gene of T. gallinae had a length of 1032bp, which contained a complete open reading frame (ORF) of 930bp long, coding for 309 amino acids. The sequence analysis revealed that the homology with three AP genes of Trichomonas vaginalis (i.e., TVU87096, TVU87097 and TVU87098) was 94.2%, 92.6% and 92.0%, respectively. It is concluded that the successfully cloned AP gene from T. gallinae will provide the basis for the expression of the AP gene in prokaryotic and eukaryotic cells and the preparation of its recombinant protein.

Elevated glutathione production by adding precursor amino acids coupled with ATP in high cell density cultivation of Candida utilis

AIMS

Three precursor amino acids and adenosine triphosphate (ATP) are necessary for fermentative production of glutathione. In this study, our aims were to develop a strategy to enhance glutathione production by adding three precursor amino acids coupled with ATP in high cell density (HCD) cultivation of Candida utilis.

METHODS AND RESULTS

A high-glutathione yeast strain, C. utilis WSH 02-08, was used in this study. Whole fermentative process for glutathione production was divided into two phases of cell growth and glutathione synthesis. Cells concentration was increased by HCD cultivation. Meanwhile, intracellular glutathione content was enhanced by the addition of three precursor amino acids. Concentrations of three precursor amino acids added at stationary phase were optimized by response surface methodology. Moreover, the addition of ATP 15 h after the addition of the three amino acids can further enhance glutathione production. Based on aforementioned phenomenon, a strategy of adding three precursor amino acids coupled with ATP was developed to enhance glutathione production.

CONCLUSION

Without the addition of three precursor amino acids and the ATP, a total glutathione of 1123 mg l(-1) was achieved after 60-h cultivation. In comparison, addition of three precursor amino acid counterparts resulted in a total glutathione of 1841 mg l(-1). Moreover, by adding amino acids combined with ATP, a total glutathione of 2043 mg l(-1) was achieved after 72-h cultivation, increased by 81.9% and 11%, respectively, as compared with the control and the one without ATP addition.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report on investigating changes of the intracellular three precursor amino acids and ATP, and gamma-glutamylcysteine synthase activity in HCD cultivation of C. utilis for glutathione production. A strategy of combining addition of three precursor amino acids with ATP was developed to enhance glutathione production in C. utilis.

Using multidimensional patterns of amino acid attributes for QSAR analysis of peptides

On the basis of exploratory factor analysis, six multidimensional patterns of 516 amino acid attributes, namely, factor analysis scales of generalized amino acid information (FASGAI) involving hydrophobicity, alpha and turn propensities, bulky properties, compositional characteristics, local flexibility and electronic properties, are proposed to represent structures of 48 bitter-tasting dipeptides and 58 angiotensin-converting enzyme inhibitors. Characteristic parameters related to bioactivities of the peptides studied are selected by genetic algorithm, and quantitative structure-activity relationship (QSAR) models are constructed by partial least square (PLS). Our results by a leave-one-out cross validation are compared with the previously known structure representation method and are shown to give slightly superior or comparative performance. Further, two data sets are divided into training sets and test sets to validate the characterization repertoire of FASGAI. Performance of the PLS models developed by training samples by a leave-one-out cross validation and external validation for test samples are satisfying. These results demonstrate that FASGAI is an effective representation technique of peptide structures, and that FASGAI vectors have many preponderant characteristics such as straightforward physicochemical information, high characterization competence and easy manipulation. They can be further applied to investigate the relationship between structures and functions of various peptides, even proteins.

Compact soft x-ray spectrometer for plasma diagnostics at the Heidelberg Electron Beam Ion Trap

A compact flat-field soft x-ray grazing-incidence grating spectrometer equipped with a cryogenically cooled back-illuminated charge-coupled device camera was built and implemented at the Heidelberg Electron Beam Ion Trap. The instrument spans the spectral region from 1 to 37 nm using two different gratings. In slitless operation mode, it directly images a radiation source, in this case ions confined in an electron beam ion trap, with high efficiency and reaching hereby a resolving power of lambda/Deltalambda approximately =130 at 2 nm and of lambda/Deltalambda approximately =600 at 28 nm. Capable of automatized operation, its low noise and excellent stability make it an ideal instrument not only for spectroscopic diagnostics requiring wide spectral coverage but also for precision wavelength measurements.