A polymorphism of the GTP-cyclohydrolase I feedback regulator gene alters transcriptional activity and may affect response to SSRI antidepressants

Tetrahydrobiopterin (BH(4)) is an essential cofactor for synthesis of many neurotransmitters including serotonin. In serotonergic neurons, BH(4) is tightly regulated by GTP-cyclohydrolase I feedback regulator (GFRP). Given the pivotal role of the serotonergic system in mood disorders and selective serotonin reuptake inhibitors (SSRIs) antidepressant function, we tested the hypothesis that GFRP gene (GCHFR) variants would modify response to antidepressants in subjects with major depression. Two single nucleotide polymorphisms (rs7164342 and rs7163862) in the GCHFR promoter were identified and occurred as two haplotypes (GA or TT). A multiple regression analysis revealed that homozygous individuals for the TT haplotype were less likely to respond to the SSRI fluoxetine than to the tricyclic antidepressant nortriptyline (P = 0.037). Moreover, the TT haplotype showed a reduced transcription rate in luciferase reporter gene assays, which may impact on BH(4)-mediated neurotransmitter production, thus suggesting a biological process through which GCHFR promoter variants might influence antidepressant response.

Influence of proline-rich inositol polyphosphate 5-phosphatase, on early development of fertilized mouse eggs, via inhibition of phosphorylation of Akt

OBJECTIVES

Proline-rich inositol polyphosphate 5-phosphatase (PIPP) is one of the signal-modifying enzymes that play pivotal regulatory roles in PI3K signalling pathway. The aim of this study was to determine the role of PIPP in early development of fertilized mouse eggs, via inhibition of Akt activity and subsequent downstream signalling events.

MATERIALS AND METHODS

The mRNA transcript levels of endogenous PIPP and Akt1, Akt2, Akt3 were detected in G(1) , S, G(2) and M phases of fertilized mouse eggs by RT-PCR. Levels of exogenous PIPP, phosphorylated Akt at Ser473, dephosphorylated cdc2 at Tyr15 and levels of CCNB1, were detected respectively by immunoblotting. Changes in Akt localization were observed by fluoroimmunoassay; meanwhile, changes in activity of Akt and its downstream MPF were detected. Percentages of cells undergoing division were determined by counting, using a dissecting microscope.

RESULTS

PIPP and Akt1 transcripts were detectable in G(1), S, G(2) and M phases of fertilized mouse eggs, but Akt2 and Akt3 were not. We also observed that overexpression of PIPP in fertilized eggs decreased expression of phosphorylated Akt at Ser473 and altered membrane localization of phosphorylated Akt at Ser473 specifically. Furthermore, overexpression of PIPP resulted in decreases in mitosis-phase promoting factor activity, level of dephosphorylated cdc2 at Tyr15 and cleavage rate of fertilized mouse eggs.

CONCLUSIONS

Our data suggest, for the first time, that PIPP may affect development of fertilized mouse eggs by inhibition of level of phosphorylated Akt at Ser473 and subsequent inhibition of downstream signal cascades.

FZD7 has a critical role in cell proliferation in triple negative breast cancer

Breast cancer is genetically and clinically heterogeneous. Triple negative breast cancer (TNBC) is a subtype of breast cancer that is usually associated with poor outcome and lack of benefit from targeted therapy. We used microarray analysis to perform a pathway analysis of TNBC compared with non-triple negative breast cancer (non-TNBC). Overexpression of several Wnt pathway genes, such as frizzled homolog 7 (FZD7), low density lipoprotein receptor-related protein 6 and transcription factor 7 (TCF7) was observed in TNBC, and we directed our focus to the Wnt pathway receptor, FZD7. To validate the function of FZD7, FZD7shRNA was used to knock down FZD7 expression. Notably, reduced cell proliferation and suppressed invasiveness and colony formation were observed in TNBC MDA-MB-231 and BT-20 cells. Study of the possible mechanism indicated that these effects occurred through silencing of the canonical Wnt signaling pathway, as evidenced by loss of nuclear accumulation of β-catenin and decreased transcriptional activity of TCF7. In vivo studies revealed that FZD7shRNA significantly suppressed tumor formation, through reduced cell proliferation, in mice bearing xenografts without FZD7 expression. Our findings suggest that FZD7-involved canonical Wnt signaling pathway is essential for tumorigenesis of TNBC, and thus, FZD7 shows promise as a biomarker and a potential therapeutic target for TNBC.

Preparation of Microcrystalline Silicon Based Solar Cells at High i-layer Deposition Rates Using a Gas Jet Technique

A Gas Jet technique has been used to prepare microcrystalline silicon (μc-Si) thin films at deposition rates as high as 20 Å/s. The films have microcrystal sizes between 80 and 120 Å with a heterogeneous microstructure containing regions with columnar growth and other regions with a more randomly oriented microstructure. These materials have been used as i-layers for nip single-junction solar cells. The high deposition rates allow for fabrication of the required thicker μc-Si i-layers in a similar amount of time to those used for high quality a-SiGe:H i-layers (rates of 1-3 Å/s). Using a 610nm cutoff filter which only allows red light to strike the device, pre-light soaked short circuit currents of 8-10 mA/cm2 and 2.7% red-light efficiencies have been obtained while AM1.5 white light efficiencies are above 7%. These efficiencies are higher than those typically obtained for μc-Si cells prepared at the high i-layer growth rates using other deposition techniques. After 1000 h. of light soaking, the efficiencies on average degrade only by 2-5% (stabilized efficiencies of 2.6%) consistent with the expected high stability with the microcrystalline materials. The small amount of degradation compares with the 15-17% degradation in efficiencies for a-SiGe:H cells subjected to similar irradiation treatments (final light-soaked red light efficiencies of 3.2%). Improvements in the cell efficiencies may come through an understanding of the role that columnar microstructure and void structure plays in determining the device performance.

Amorphous Silicon Alloy Photovoltaic Technology - from R&D to Production

The key requirements for photovoltaic modules to be accepted for large-scale terrestrial applications are (i) low material cost, (ii) high efficiency with good stability, (iii) low manufacturing cost with good yield and (iv) environmental safety. Thin films of amorphous silicon alloy are inexpensive; the products are also environmentally benign. The challenge has been to improve the stable efficiency of these modules and transfer the R&D results into production. Using a Multijunction, Multi-bandgap approach to capture the solar spectrum more efficiently, we have developed one-square-foot modules with initial efficiency of 11.8%. After 1000 h of one-sun light soaking, a stable efficiency of 10.2% was obtained. Both the efficiency values were confirmed by National Renewable Energy Laboratory. The technology has been transferred to production using an automated roll-to-roll process in which different layers of the cell structure are deposited in a continuous manner onto stainless steel rolls, 14” wide and half a mile long. The rolls are next processed into modules of different sizes. This inexpensive manufacturing process produces high efficiency modules with subcell yields greater than 99%. The key features of the technology transfer and future scope for improvement are discussed.

The effects of subinhibitory concentrations of costus oil on virulence factor production in Staphylococcus aureus

AIM

To determine the antimicrobial activity of costus (Saussurea lappa) oil against Staphylococcus aureus, and to evaluate the influence of subinhibitory concentrations of costus oil on virulence-related exoprotein production in staph. aureus.

METHODS AND RESULTS

Minimal inhibitory concentrations (MICs) were determined using a broth microdilution method, and the MICs of costus oil against 32 Staph. aureus strains ranged from 0.15 to 0.6 μl ml(-1) . The MIC(50) and MIC(90) were 0.3 and 0.6 μl ml(-1) , respectively. Western blot, haemolytic, tumour necrosis factor (TNF) release and real-time RT-PCR assays were performed to evaluate the effects of subinhibitory concentrations of costus oil on virulence-associated exoprotein production in Staph. aureus. The data presented here show that costus oil dose dependently decreased the production of α-toxin, toxic shock syndrome toxin 1 (TSST-1) and enterotoxins A and B in both methicillin-sensitive Staph. aureus (MSSA) and methicillin-resistant Staph. aureus (MRSA).

CONCLUSION

Costus oil has potent antimicrobial activity against Staph. aureus, and the production of α-toxin, TSST-1 and enterotoxins A and B in Staph. aureus was decreased by costus oil.

SIGNIFICANCE AND IMPACT OF THE STUDY

The data suggest that costus oil may deserve further investigation for its potential therapeutic value in treating Staph. aureus infections. Furthermore, costus oil could be rationally applied in food products as a novel food preservative both to inhibit the growth of Staph. aureus and to repress the production of exotoxins, particularly staphylococcal enterotoxins.

A rare case of Gerbode defect associated with double orifice mitral valve

Gerbode defect is an unusual cardiac defect; its association with a double orifice mitral valve has not been previously reported. We present a case of a 45-year-old woman who complained of palpitation and dyspnea on exertion. Echocardiography revealed an abnormal communication between the left ventricle and the right atrium, but misinterpreted a double orifice mitral valve as fusion of the anterolateral commissure. The Gerbode defect was closed during cardiopulmonary bypass, while the double orifice mitral valve was left untouched. The patient was discharged 16 days postoperatively.

The synergy of honokiol and fluconazole against clinical isolates of azole-resistant Candida albicans

AIMS

To evaluate the interaction of fluconazole (FLC) and honokiol (HNK) in vitro and vivo against azole-resistant (azole-R) clinical isolates of Candida albicans.

METHODS AND RESULTS

A checkerboard microdilution method was used to study the in vitro interaction of FLC and HNK in 24 azole-R clinical isolates of C. albicans. In vivo antifungal activity was performed to further analyse the interaction between FLC and HNK. In the in vitro study, synergism was observed in all 24 FLC-resistant strains tested as determined by fractional inhibitory concentration index (FICI), and in 22 strains by Delta E models. No antagonistic activity was observed in any of the strains tested. These positive interactions were also confirmed by using the time-killing test for the selected strain C. albicans YL371, which shows strong susceptible to the combination of HNK and FLC. In the in vivo study, the mice with candidiasis were treated successfully by a combination therapy of HNK with FLC, the results showed a decrease of the colony forming unit in infected and treated animals compared to the controls, at the conditions of the treatment used in this study.

CONCLUSIONS

Synergistic activity of HNK and FLC against clinical isolates of FLC-resistant C. albicans was observed in vitro and in vivo.

SIGNIFICANCE AND IMPACT OF THE STUDY

This report might provide a potential therapeutic method to overcome the problem of drug-resistance in C. albicans.

Assessment of Transvaginal Sonography Combined with Endometrial Cytology as a Mass Screening Method for Endometrial Cancer in Beijing

This was a two-phase, large sample-group study assessing the effectiveness of combined transvaginal sonography (TVS) and endometrial cytology in endometrial cancer screening. In phase one, 3308 women without known cancer were enrolled and TVS was performed on those with symptoms or endometrial cancer risk factors. Endometrial cytology was carried out on post-menopausal women with endometrial thickness ≥ 5 mm and on pre-menopausal women with endometrial thickness ≥ 10 mm. Dilation and curettage (D & C) was performed if cytological findings were inconclusive, or indicated cancer or pre-cancer. The mass screening safety interval is at least 2 years and phase two was carried out 2 years after phase one, using the same procedures, on the 3305 women who were originally found to be cancer free. Combined TVS and endometrial cytology resulted in 100% sensitivity and 99.0% specificity, reducing unnecessary D & C by 91.7% and screening costs by 20.1%. Combined TVS examination and endometrial cytology decreased potentially harmful examinations, patient suffering and medical costs, and is worth considering for broad implementation.

Guangdong and Florida populations of 'Candidatus Liberibacter asiaticus' distinguished by a genomic locus with short tandem repeats

Huanglongbing (HLB) (yellow shoot disease) is a highly destructive disease that threatens citrus production worldwide. The disease was first observed in Guangdong, P.R. China, over 100 years ago, and was found in Florida, United States, in 2005. 'Candidatus Liberibacter asiaticus' has been associated with HLB in many citrus-growing regions around the world, including Guangdong and Florida. The global epidemiology of HLB, as well as management of the disease, relies on knowledge of 'Ca. L. asiaticus' populations in different geographical regions around the world. In this study, we identified a genetic marker containing small tandem repeats in the genome of 'Ca. L. asiaticus' and comparatively analyzed the tandem repeat numbers (TRNs) in 'Ca. L. asiaticus' populations from Guangdong and Florida. Analyses of TRNs showed that the bacterial population in Guangdong was different from that in Florida. The Guangdong population consisted predominately of strains with a TRN of 7 (TRN(7)) at a frequency of 47.6%. The Florida population consisted predominately of strains with a TRN of 5 (TRN(5)) at a frequency of 84.4%. TRNs ranged from 3 to 16. The apparent absence of TRNs of 9, 10, 11, and 12 separated the bacterial strains into two groups: TRNs < 10 (TRN(<10)) and TRNs > 10 (TRN(>10)). In Florida, TRN(<10) strains (103/109, or 94.5%) were widely distributed in all HLB-affected counties. TRN(>10) strains (6/109, or 5.5%) were found in central Florida. This is the first report documenting the differentiation of 'Ca. L. asiaticus' populations between Asia and North America and the possible presence of two differentially distributed genotypes of 'Ca. L. asiaticus' in Florida.

Aerodynamic damping during rapid flight maneuvers in the fruit fly Drosophila

We systematically investigated the effect of body rotation on the aerodynamic torque generation on flapping wings during fast turning maneuvers (body saccades) in the fruit fly Drosophila. A quasi-steady aerodynamic simulation of turning maneuvers with symmetrically flapping wings showed that body rotation causes a substantial aerodynamic counter-torque, known as flapping counter-torque (FCT), which acts in the opposite direction to turning. Simulation results further indicate that FCTs are linearly dependent on the rotational velocity and the flapping frequency regardless of the kinematics of wing motion. We estimated the damping coefficients for the principal rotation axes - roll, pitch, yaw - in the stroke plane frame. FCT-induced passive damping exists about all the rotation axes examined, suggesting that the effects of body rotation cannot be ignored in the analysis of free-flight dynamics. Force measurements on a dynamically scaled robotic wing undergoing realistic saccade kinematics showed that although passive aerodynamic damping due to FCT can account for a large part of the deceleration during saccades, active yaw torque from asymmetric wing motion is required to terminate body rotation. In addition, we calculated the mean value of the damping coefficient at 21.00 x10(-12) N m s based on free-flight data of saccades, which is somewhat lower than that estimated by the simulation results (26.84 x 10(-12) N m s).

Impaired angiogenesis in aging myocardial microvascular endothelial cells is associated with reduced importin alpha and decreased nuclear transport of HIF1 alpha: mechanistic implications

Aging is associated with increased incidence of myocardial infarctions and impaired angiogenesis - new capillary blood vessel formation from preexisting vessels. The molecular mechanism(s) of aging-related impairment of angiogenesis are unknown. In the present study we focused on the mechanism of activation of the gene for vascular endothelial growth factor (VEGF - the most potent stimulator of angiogenesis) in young and aging myocardial microvascular endothelial cells (MMEC). Activation of VEGF gene in the cell nucleus is mediated in part by the transcription factor hypoxia-inducible factor 1 alpha (HIF1 alpha). In order to activate VEGF gene, HIF1 alpha must first be transported to the nucleus, but the mechanisms of this transport are unknown. We hypothesized that reduced VEGF gene activation and impaired angiogenesis in myocardium during aging can result from downregulation of the nuclear transport receptor - importin alpha that leads to decreased transport of HIF1 alpha to the nucleus. We examined in MMEC isolated from young (3 months of age) and aging (24 months old) Fisher F-344 rats: 1) in vitro angiogenesis; and 2) the expression of VEGF, importin alpha and HIF1 alpha. Aging MMEC exhibited a 3.7-fold reduction in angiogenesis and a corresponding reduction in VEGF (by 3-fold) and importin alpha (by 1.9-fold) levels compared to young MMEC. Aging MMEC also exhibited cytoplasmic accumulation (by 1.8-fold) of HIF1 alpha protein, reduced HIF1 alpha transport to the nucleus and decreased binding of HIF1 alpha protein to the VEGF gene promoter. This study is the first demonstration of the downregulation of importin alpha in aging MMEC and reduced nuclear transport of HIF1 alpha, which likely lead to decreased VEGF gene activation and impaired angiogenesis.

Comparison of three current sources for single-electrode capacitance measurement

The capacitance of a single electrode is usually measured by injecting a current to the electrode and measuring the resultant voltage on the electrode. In this case, a voltage-controlled current source with a high bandwidth is needed because the impedance is inversely proportional to the excitation frequency. In this design note, three different current sources are discussed: (1) the Howland current source, (2) a modified Howland current source, and (3) a dual op-amp current source. The principle and dynamic performances are presented and compared. Simulation and experimental results show that although the Howland current source has the lowest (i.e., worst) output impedance, its output is the most stable among the three current sources when the frequency changes. Therefore, it is suitable for single-electrode capacitance measurement. Initial tests have proven the feasibility of single-electrode capacitance sensor with the Howland current source.

Hepatocyte nuclear factor 4alpha attenuates hepatic fibrosis in rats

BACKGROUND AND AIMS

Hepatocyte nuclear factor 4alpha (HNF4alpha) is a central transcriptional regulator of hepatocyte differentiation and function. The aim of this study was to evaluate the effect of HNF4alpha on attenuation of hepatic fibrosis.

METHODS

The adenoviruses carrying HNF4alpha gene or containing siRNA targeting HNF4alpha were injected through tail vein on two distinct hepatic fibrosis models either induced by dimethylnitrosamine or by bile duct ligation in rats. Moreover, HNF4alpha, epithelial-mesenchymal transition (EMT)-related and fibrotic markers in hepatocytes, hepatic stellate cells (HSCs) and liver tissues were detected by real time PCR, immunofluorescence or immunohistochemistry.

RESULTS

We demonstrated that decreased expression of HNF4alpha and epithelial markers accompanied by enhanced expression of mesenchymal markers occurred in fibrotic liver. More importantly, forced expression of HNF4alpha remarkably alleviated hepatic fibrosis and improved liver function with suppression of EMT in both fibrosis models. In contrast, downregulation of HNF4alpha by siRNA aggravated hepatic fibrosis and decreased the expression of E-cadherin in association with the enhanced expression of vimentin and fibroblast-specific protein-1. In vitro study revealed that HNF4alpha could suppress the EMT process of hepatocytes induced by transforming growth factor-beta1 and increase the expression of liver-specific genes. A similar phenomenon of the EMT process was observed during the activation of HSCs, which was abrogated by HNF4alpha. Additionally, HNF4alpha deactivated the myofibroblasts through inducing the mesenchymal-to-epithelial transition and inhibited their proliferation.

CONCLUSIONS

Our study suggests that HNF4alpha is critical for hepatic fibrogenesis and upregulation of HNF4alpha might present as an ideal option for the treatment of hepatic fibrosis.

Simulating the ES-SAGD Process With Solvent Mixture in Athabasca Reservoirs

Abstract

The ES-SAGD process was developed to improve the energy and oil drainage efficiency of the SAGD process. The idea of the ES-SAGD process is to co-inject solvent with steam and the co-injected solvent mixes with the bitumen to further reduce the viscosity of the heated bitumen along the boundary of the steam chamber thus enhances the oil recovery. Practically, the co-injected solvent will be a solvent mixture (such as diluent /naphtha) because of its availability and reduced cost than a pure hydrocarbon. This paper reports the results of an ES-SAGD lab test conducted with steam and diluent co-injection using Athabasca bitumen. To simulate the ES-SAGD test, a pseudo-component scheme to represent the complex solvent mixture in the numerical model is derived, based on the diluent composition and measured PVT data. The behaviours and effects of the co-injected solvent in the ES-SAGD process are analyzed through detailed history matching of the ES-SAGD test. Numerical sensitivity analyses are also performed to investigate the effects of some key parameters in the numerical approach.

Introduction

The Steam Assisted Gravity Drainage (SAGD)(1) and the Vapour Extraction (VAPEX)(2), combined with the horizontal well technology, are being developed to recover the enormous heavy oil and bitumen resources in Western Canada. The SAGD process has been successfully field-tested and is in the early stage of commercial-scale application, while the VAPEX process is still at the piloting stage. Both processes have their advantages and disadvantages. The advantage of the SAGD process is its high oil production rate. However, the high production rate of the SAGD process is associated with intensive energy consumption and CO2 emissions from burning natural gas to generate steam, and costly post-production water treatment. The VAPEX process, on the other hand, has the advantage of lower energy consumption and water usage, and therefore less CO2 emission and water treatment cost. However, the major drawbacks of the VAPEX process are its relatively lower oil production rate and the additional cost of solvent.

Selective Effects of Glucose, Insulin and Leptin by Molecular Breast Cancer Subtype

Background: Type II diabetes and obesity are important risk factors for post-menopausal luminal A (LA) and triple negative (TN) pre-menopausal breast cancers, particularly in African American (AA) and Hispanic women. Breast cancer patients with these chronic metabolic diseases also have a worse prognosis, independent of other factors. We have published that metformin inhibits cell growth (S phase arrest) and induces apoptosis, only in TN cell lines in vivo and in vitro. It is less active, growth inhibitory (G1 arrest) and does not induce apoptosis in other breast cancer cell subtypes (Cell Cycle, 2009).Methods: We investigated the effects of glucose as a mitogen at physiologic (5mM), metabolic syndrome (7mM) or diabetic levels (10mM), with or without insulin (100 ng/ml) or leptin (100 ng/ml) using cell lines representing all molecular subtypes of breast cancer. Metformin was then used in combination with the above, to determine whether it would block the mitogenic or signaling effects of supraphysiological glucose, insulin or leptin.Results: The LA (MCF-7) and 2 of 5 TN cell lines (derived from AA patients; HCC 1806 and MDA 468) showed the most cell growth in response to glucose &gt;5mM (75% for MCF-7, 30-50% for AA TN lines). Three TN cell lines from Caucasians (MDA231, HCC1937, BT20), the HER2 (SKBR3) and luminal B (BT-474) cells showed less growth induction with glucose &gt;5mM. In TN lines only, glucose associated mitogenesis was associated with increased EGFR, pEGFR, IGF1R, pIGF1R, AKT and pAKT and decreases in AMPK, pAMPK, p38, IRS2, and the cyclins D1, E and A in a dose dependent manner. Metformin abrogated glucose induced cell growth and the aforementioned protein expression/phosphorylation changes involving EGFR, IGF1R, and AKT, increased AMPK and pAMPK and induced a profound reduction in Cyclin D1 across all glucose concentrations in TN cell lines from AA women. It reduced but did not eliminate glucose associated mitogenesis in the TN cell lines from Caucasian patients. Metformin had a more variable effect on cell lines of other molecular subtypes grown under high glucose conditions. The 5 TN breast cancer cell lines were uniformly resistant to both leptin and insulin associated mitogenesis, across a wide range of glucose concentrations. In contrast, both leptin and insulin significantly promoted LA breast cancer cell growth. These effects were resistant to metformin treatment. Leptin and insulin had the least growth promoting effects on HER2 breast cancer cell lines, whereas they induced modest growth induction in LB cell lines.Conclusions: All TN cell lines showed significant mitogenesis in response to glucose &gt;5mM, whereas they were uniformly resistant to both leptin and insulin. The glucose associated mitogenesis was more pronounced in lines derived from AA patients, as were the anti-mitgenic effects of metformin. LA cells showed marked growth induction by glucose, leptin and insulin, whereas HER2 cell lines showed general resistance to all of these factors. These data suggest that metabolic and hormonal shifts with obesity and diabetes, as well as metformin response vary by the molecular subtype of breast cancer cells and ethnicity.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5154.

A role for a cell wall localized glycine-rich protein in dehydration and rehydration of the resurrection plant Boea hygrometrica

The acquisition of desiccation tolerance in dicotyledonous angiosperms requires the induction of a co-ordinated programme of genetic and biochemical processes during drying and the adaptive mechanisms are primarily protoplasmic in nature. Recent studies have shown that changes in cell wall structure and composition are also important for recovery after drying, however, the molecular mechanisms that underpin these adaptive responses are largely unknown. Here, the desiccation-tolerant plant Boea hygrometrica was used as a model system to investigate the changes in gene expression and cell wall adaptation that take place during extreme dehydration. A cDNA macroarry analysis of dehydration-inducible genes led to the identification of a gene encoding a glycine-rich protein (BhGRP1). The corresponding transcript was up-regulated during drying in B. hygrometrica leaves. In silico analysis revealed that BhGRP1 is targeted to the cell wall and this was confirmed in planta. Morphological changes in the cell wall architecture were also observed during the process of drying and re-watering. Concomitant with this observation, cell wall profiling by Fourier transform infrared spectroscopy indicated that protein levels increased upon desiccation and remained broadly similar upon re-watering. These findings suggest that the deposition of BhGRP1 may play a role in cell wall maintenance and repair during dehydration and rehydration in B. hygrometrica.