Atomic-beam alignment of inorganic materials for liquid-crystal displays

The technique used to align liquid crystals-rubbing the surface of a substrate on which a liquid crystal is subsequently deposited-has been perfected by the multibillion-dollar liquid-crystal display industry. However, it is widely recognized that a non-contact alignment technique would be highly desirable for future generations of large, high-resolution liquid-crystal displays. A number of alternative alignment techniques have been reported, but none of these have so far been implemented in large-scale manufacturing. Here, we report a non-contact alignment process, which uses low-energy ion beams impinging at a glancing angle on amorphous inorganic films, such as diamond-like carbon. Using this approach, we have produced both laptop and desktop displays in pilot-line manufacturing, and found that displays of higher quality and reliability could be made at a lower cost than the rubbing technique. The mechanism of alignment is explained by adopting a random network model of atomic arrangement in the inorganic films. Order is induced by exposure to an ion beam because unfavourably oriented rings of atoms are selectively destroyed. The planes of the remaining rings are predominantly parallel to the direction of the ion beam.

Androgen receptor functions in castration-resistant prostate cancer and mechanisms of resistance to new agents targeting the androgen axis

The metabolic functions of androgen receptor (AR) in normal prostate are circumvented in prostate cancer (PCa) to drive tumor growth, and the AR also can acquire new growth-promoting functions during PCa development and progression through genetic and epigenetic mechanisms. Androgen deprivation therapy (ADT, surgical or medical castration) is the standard treatment for metastatic PCa, but patients invariably relapse despite castrate androgen levels (castration-resistant PCa, CRPC). Early studies from many groups had shown that AR was highly expressed and transcriptionally active in CRPC, and indicated that steroids from the adrenal glands were contributing to this AR activity. More recent studies showed that CRPC cells had increased expression of enzymes mediating androgen synthesis from adrenal steroids, and could synthesize androgens de novo from cholesterol. Phase III clinical trials showing a survival advantage in CRPC for treatment with abiraterone (inhibitor of the enzyme CYP17A1 required for androgen synthesis that markedly reduces androgens and precursor steroids) and for enzalutamide (new AR antagonist) have now confirmed that AR activity driven by residual androgens makes a major contribution to CRPC, and led to the recent Food and Drug Administration approval of both agents. Unfortunately, patients treated with these agents for advanced CRPC generally relapse within a year and AR appears to be active in the relapsed tumors, but the molecular mechanisms mediating intrinsic or acquired resistance to these AR-targeted therapies remain to be defined. This review outlines AR functions that contribute to PCa development and progression, the roles of intratumoral androgen synthesis and AR structural alterations in driving AR activity in CRPC, mechanisms of action for abiraterone and enzalutamide, and possible mechanisms of resistance to these agents.

Expression patterns of FHL/SLIM family members suggest important functional roles in skeletal muscle and cardiovascular system

LIM domain containing proteins play critical roles in animal development and cellular differentiation. Here, we describe the cloning and expression patterns of three members of the four and a half LIM domain-only protein family, FHL1, 2, and 3, from mouse. A comparison of embryonic expression patterns of these three highly-related genes indicates that they are expressed in an overlapping pattern in the developing cardiovascular system, and skeletal muscle. In adult tissues, the three genes are expressed in a predominant and overlapping manner in cardiac and skeletal muscle. Of the three genes, FHL2 appears to have the most restricted expression pattern during development, in heart, blood vessels, and skeletal muscle. Expression in heart is highest in cardiac septa and in the region adjacent to the atrio-ventricular ring, suggesting a potential role in septation or conduction system development. In the heart, FHL1expression was observed strongly in developing outflow tract, and to a lesser extent in myocardium. FHL3 displays low and ubiquitous expression during mouse development. Cardiac ventricular expression of FHL1, but not FHL2 or FHL3, was upregulated in two mouse models of cardiac hypertrophic and dilated cardiomyopathy. Taken together, these data indicate the potential importance of this FHL family in the development and maintenance of the cardiovascular system and striated muscle, and suggest that FHL1 may play a role in the development of heart disease.

Adult bone-marrow-derived mesenchymal stem cells contribute to wound healing of skin appendages

Adult bone-marrow-derived mesenchymal stem cells (MSCs) are well-established as having the capacity to differentiate into cells with mesodermal, ectodermal, and endodermal characteristics and can leave their niche to home toward and engraft within foreign tissues. To investigate whether adult MSCs contribute to the repair of skin appendages after injury, BrdU-labeled MSCs were co-cultured with heat-shocked confluent sweat gland cells (SGCs) in vitro and later intravenously injected into full-thickness skin wounds in rats. When adult MSCs were co-cultured with heat-shocked SGCs, a subset of adult MSCs differentiated into SGCs, the percentage of differentiation being enhanced by epidermal growth factor and the injured microenviroment, but weakened by PD98059. The ERK (extracellular signal-regulated kinase) pathway, especially pERK, was involved in the phenotype conversion of human MSCs into human SGC. Labeled MSCs were noted in hair follicles, sebaceous glands, blood vessels, and dermis in full-thickness wounds, and the incorporated cells in hair follicles and sebaceous glands were also positive for pan-cytokeratin. After wound healing, some labeled MSCs returned to the bone marrow, whereas other were retained in the dermis. We conclude that adult MSCs have the capacity to dock at specific sites, to contribute to wound healing of skin appendages, and to home toward marrow, and that engraftment of bone-marrow-derived cells is a functional event.

Mesoscopic correlation of supramolecular chirality in one-dimensional hydrogen-bonded assemblies

The ordering of 4-[trans-2-(pyrid-4-yl-vinyl)] benzoic acid, a two-dimensional chiral species, was studied by scanning tunneling microscopy at noble metal surfaces. Homochiral molecules self-assemble in supramolecular chiral hydrogen-bonded twin chains, which order in nanogratings where the supramolecular chirality is strictly correlated over the entire microm domains without intimate molecular contact. Model simulations indicate that the underlying mesoscopic chiral resolution is associated with twin chains acting as chiroselective templates for transient molecular attachment, which process mediates the gratings' evolution.

The use of phenome-wide association studies (PheWAS) for exploration of novel genotype-phenotype relationships and pleiotropy discovery

The field of phenomics has been investigating network structure among large arrays of phenotypes, and genome-wide association studies (GWAS) have been used to investigate the relationship between genetic variation and single diseases/outcomes. A novel approach has emerged combining both the exploration of phenotypic structure and genotypic variation, known as the phenome-wide association study (PheWAS). The Population Architecture using Genomics and Epidemiology (PAGE) network is a National Human Genome Research Institute (NHGRI)-supported collaboration of four groups accessing eight extensively characterized epidemiologic studies. The primary focus of PAGE is deep characterization of well-replicated GWAS variants and their relationships to various phenotypes and traits in diverse epidemiologic studies that include European Americans, African Americans, Mexican Americans/Hispanics, Asians/Pacific Islanders, and Native Americans. The rich phenotypic resources of PAGE studies provide a unique opportunity for PheWAS as each genotyped variant can be tested for an association with the wide array of phenotypic measurements available within the studies of PAGE, including prevalent and incident status for multiple common clinical conditions and risk factors, as well as clinical parameters and intermediate biomarkers. The results of PheWAS can be used to discover novel relationships between SNPs, phenotypes, and networks of interrelated phenotypes; identify pleiotropy; provide novel mechanistic insights; and foster hypothesis generation. The PAGE network has developed infrastructure to support and perform PheWAS in a high-throughput manner. As implementing the PheWAS approach has presented several challenges, the infrastructure and methodology, as well as insights gained in this project, are presented herein to benefit the larger scientific community.

BMP signaling is required for heart formation in vertebrates

In these studies, we have taken advantage of a transient transgenic strategy in Xenopus embryos to demonstrate that BMP signaling is required in vivo for heart formation in vertebrates. Ectopic expression of dominant negative Type I (tALK3) or Type II (tBMPRII) BMP receptors in developing Xenopus embryos results in reduction or absence of heart formation. Additionally, blocking BMP signaling in this manner downregulates expression of XNkx2-5, a homeobox gene required for cardiac specification, prior to differentiation. Notably, however, initial expression of XNkx2-5 is not affected. Mutant phenotypes can be rescued by co-injection of mutant with wild-type receptors or co-injection of mutant receptors with XSmad1, a downstream mediator of BMP signaling. Whole-mount in situ analyses indicate that ALK3 and XSmad1 are coexpressed in cardiogenic regions. Together, our results demonstrate that BMP signaling is required for maintenance of XNkx2-5 expression and heart formation and suggest that ALK3, BMPRII, and XSmad1 may mediate this signaling.

Estimation of the impact of genital warts on health-related quality of life

OBJECTIVES

One of the two new human papillomavirus (HPV) vaccines protects against HPV types 6 and 11, which cause over 95% of genital warts, in addition to protecting against HPV types 16 and 18. In anticipation of HPV vaccine implementation, the impact of genital warts on health-related quality of life (HRQoL) was measured to assess the potential benefits of the quadrivalent over the bivalent vaccine.

METHODS

Genitourinary medicine clinic patients aged 18 years and older with a current diagnosis of genital warts were eligible; 81 consented and were interviewed by a member of the research team. A generic HRQoL questionnaire, the EQ-5D (comprising EQ-5D index and EQ visual analogue scale (VAS) scores) and a disease-specific HRQoL instrument, the CECA10, were administered. Previously established UK population norms were used as a control group for EQ-5D comparisons.

RESULTS

Cases (with genital warts) had lower EQ VAS and EQ-5D index scores than controls. After adjusting for age a mean difference between cases and controls 30 years of age and under (n = 70) of 13.9 points (95% CI 9.9 to 17.6, p<0.001) for the EQ VAS and 0.039 points (95% CI 0.005 to 0.068, p = 0.02) on the EQ-5D index (also adjusted for sex) was observed. The difference between cases and controls for the EQ VAS was especially notable in young women.

CONCLUSIONS

Genital warts are associated with a significant detriment to HRQoL. The potential added benefit of preventing most cases of genital warts by HPV vaccination should be considered in decisions about which HPV vaccine to implement in the United Kingdom.

(S)- or (R)-3-(E-enoyl)-4-phenyl-1,3-oxazolidin-2-ones: ideal Michael acceptors to afford a virtually complete control of simple and face diastereoselectivity in addition reactions with glycine derivatives

[formula: see text] Enantiomerically pure (S)- or (R)-3-(E-enoyl)-4-phenyl-1,3-oxazolidin-2-ones were found to serve as ideal Michael acceptors in addition reactions with achiral Ni(II) complexes of glycine Schiff bases. Virtually complete control of simple and face diastereoselectivity, observed in these reactions, combined with quantitative chemical yields renders this methodology synthetically superior to the previous methods.

Rational design of highly diastereoselective, organic base-catalyzed, room-temperature Michael addition reactions

Via the rational design of a single-preferred transition state, stabilized by electron donor-acceptor-type attractive interactions, structural and geometric requirements for the corresponding starting compounds have been determined. The Ni(II) complex of the Schiff base of glycine with o-[N-alpha-picolylamino]acetophenone, as a nucleophilic glycine equivalent, and N-(trans-enoyl)oxazolidin-2-ones, as derivatives of an alpha,beta-unsaturated carboxylic acid, were found to be the substrates of choice featuring geometric/conformational homogeneity and high reactivity. The corresponding Michael addition reactions were found to proceed at room temperature in the presence of catalytic amounts of DBU to afford quantitatively the addition products with virtually complete diastereoselectivity. Acidic decomposition of the products followed by treatment of the reaction mixture with NH4OH gave rise to the diastereomerically pure 3-substituted pyroglutamic acids.

Biological and conformational study of beta-substituted prolines in MT-II template: steric effects leading to human MC5 receptor selectivity

To investigate the molecular basis for the interaction of the chi-constrained conformation of melanotropin peptide with the human melanocortin receptors, a series of beta-substituted proline analogs were synthesized and incorporated into the Ac-Nle-C[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 (MT-II) template at the His6 and D-Phe7 positions. It was found that the binding affinities generally diminished as the steric bulk of the p-substituents of the 3-phenylproline residues increased. From (2S, 3R)-3-phenyl-Pro6 to (2S, 3R)-3-(p-methoxyphenyl)-Pro6 analogs the binding affinity decreased 23-fold at the human melanocortin-3 receptor (hMC3R), 17-fold at the hMC4R, and eight-fold at the hMC5R, but selectivity for the hMC5R increased. In addition, the substitution of the D-Phe7 residue with a (2R, 3S)-3-phenyl-Pro resulted in greatly reduced binding affinity (10(3)-10(5)) at these melanocortin receptors. Macromodel's Large Scale Low Mode (LLMOD) with OPLS-AA force field simulations revealed that both MT-II and SHU-9119 share a similar backbone conformation and topography with the exception of the orientation of the side chains of D-Phe7/D-Nal (2')7 in chi space. Introduction of the dihedrally constrained phenylproline analogs into the His6 position (analogs 2-6) caused topographical changes that might be responsible for the lower binding affinities. Our findings indicate that hMC3 and hMC4 receptors are more sensitive to steric effects and conformational constraints than the hMC5 receptor. This is the first example for melanocortin receptor selectivity where the propensity of steric interactions in chi space of beta-modified Pro6 analogs of MT-II has been shown to play a critical role for binding as well as bioefficacy of melanotropins at hMC3 and hMC4 receptors, but not at the hMC5 receptor.

Michael addition reactions between chiral Ni(II) complex of glycine and 3-(trans-enoyl)oxazolidin-2-ones. A case of electron donor-acceptor attractive interaction-controlled face diastereoselectivity

This study has demonstrated that the readily available and inexpensive 3-(trans-3'-alkyl/arylpropenoyl)oxazolidin-2-ones, featuring high electrophilicity and conformational homogeneity, are synthetically superior Michael acceptors over the conventionally used alkyl enoylates, allowing for a remarkable improvement in reactivity and, in most cases, diastereoselectivity of the addition reactions with a Ni(II) complex of the chiral Schiff base of glycine with (S)-o-[N-(N-benzylprolyl)amino]benzophenone. Kinetically controlled diastereoselectivity in the corresponding Michael addition reactions between the Ni(II) complex of glycine and the oxazolidin-2-ones was systematically studied as a function of steric, electronic, and position effects of the substituents on the starting Michael acceptor. In both aliphatic and aromatic series the simple diastereoselectivity was found to be virtually complete, affording the products via the corresponding TSs with the approach geometry like. The face diastereoselectivity of the reactions between the Ni(II) complex of glycine and the 3-(trans-3'-alkylpropenoyl)oxazolidin-2-ones was found to depend exclusively on the steric bulk of the alkyl group on the starting Michael acceptor. In contrast, the face diastereoselectivity in the reactions of aromatic oxazolidin-2-ones with the Ni(II) complex of glycine was shown to be controlled predominantly by the electronic properties of the aryl ring. In particular, the additions of the Ni(II) complex of glycine with 3-(trans-3'-arylpropenoyl)oxazolidin-2-ones, bearing electron-withdrawing substituents on the phenyl ring, afforded the (2S,3R)-configured products with synthetically useful diastereoselectivity and in quantitative chemical yields, thus allowing for an efficient access to the sterically constrained beta-aryl-substituted pyroglutamic and glutamic acids.

Facilitatory and inhibitory effects of Kinesio tape: Fact or fad?

OBJECTIVES

Kinesio tape (KT) is a commonly used intervention in sports. It claims to be able to alter the muscle activity, in terms of both facilitation and inhibition, by certain application methods. This study compared the neuromuscular activity of the wrist extensor muscles and maximal grip strength with facilitatory, inhibitory KT, and tapeless condition in healthy adults who were ignorant about KT. Potential placebo effects were eliminated by deception.

DESIGN

Randomized deceptive trial.

METHODS

33 participants performed maximal grip assessment in a randomly assigned order of three taping conditions: true facilitatory KT, inhibitory KT, and no tape. The participants were blindfolded during the evaluation. Under the pretense of applying a series of adhesive muscle sensors, KT was applied to their wrist extensor muscles of the dominant forearm in the first two conditions. Within-subject comparisons of normalized root mean square of the wrist extensors electromyographic activity and maximal grip strength were conducted across three taping conditions.

RESULTS

31 out of 33 enlisted participants were confirmed to be ignorant about KT. No significant differences were found in the maximum grip strength (p=0.394), electromyographic activity (p=0.276), and self-perceived performance (p=0.825) between facilitatory KT, inhibitory KT, and tapeless conditions.

CONCLUSIONS

Neither facilitatory nor inhibitory effects were observed between different application techniques of KT in healthy participants. Clinically, alternative method should be used for muscle activity modulation.

c-Jun enhancement of androgen receptor transactivation is associated with prostate cancer cell proliferation

Androgens and the androgen receptor (AR) are involved in the growth and progression of prostate cancer. Our previous studies suggest that the proto-oncoprotein c-Jun is an AR coactivator that stimulates AR transactivation by mediating receptor dimerization and subsequent DNA binding. To study the physiological relevance of this c-Jun activity on AR, we have generated stable LNCaP cell lines expressing different levels of c-Jun. These cell lines exhibit a direct correlation between endogenous c-Jun levels and AR transcriptional activity and expression of endogenous androgen-regulated genes. Disruption by antisense RNA of endogenous c-Jun expression in LNCaP cells strongly compromises the androgen-dependent proliferation of these cells. In contrast, expression of a c-Jun mutant, which is fully active in coactivation of AR but deficient in AP-1 transactivation, significantly enhances androgen-dependent proliferation. This finding indicates that the coactivation function of c-Jun is sufficient for regulating androgen-induced growth of LNCaP cells. c-Jun also enhances AR transactivtion in androgen-independent LNCaP cells, which closely mimic hormone-refractory prostate cancer cells in gene expression and growth behavior. Importantly, siRNA-mediated repression of endogenous c-Jun expression results in markedly reduced growth of these cells, strongly suggesting an important biological role for c-Jun in hormone-refractory prostate cancer.

Band insulator to Mott insulator transition in 1T-TaS2

1T-TaS₂ undergoes successive phase transitions upon cooling and eventually enters an insulating state of mysterious origin. Some consider this state to be a band insulator with interlayer stacking order, yet others attribute it to Mott physics that support a quantum spin liquid state. Here, we determine the electronic and structural properties of 1T-TaS₂ using angle-resolved photoemission spectroscopy and X-Ray diffraction. At low temperatures, the 2π/2c-periodic band dispersion, along with half-integer-indexed diffraction peaks along the c axis, unambiguously indicates that the ground state of 1T-TaS₂ is a band insulator with interlayer dimerization. Upon heating, however, the system undergoes a transition into a Mott insulating state, which only exists in a narrow temperature window. Our results refute the idea of searching for quantum magnetism in 1T-TaS₂ only at low temperatures, and highlight the competition between on-site Coulomb repulsion and interlayer hopping as a crucial aspect for understanding the material’s electronic properties.

1T-TaS2 possesses complex electronic phase behaviors in transition-metal di-chalcogenides, undergoing several charge-ordered phases before finally into an insulating state of unknown origin. Here, the authors determine its electronic and structural properties experimentally, revealing its origin.

Regulation of the tinman homologues in Xenopus embryos

Vertebrate homologues of the Drosophila tinman transcription factor have been implicated in the processes of specification and differentiation of cardiac mesoderm. In Xenopus three members of this family have been isolated to date. Here we show that the XNkx2-3, Xnkx2-5, and XNkx2-10 genes are expressed in increasingly distinctive patterns in endodermal and mesodermal germ layers through early development, suggesting that their protein products (either individually or in different combinations) perform distinct functions. Using amphibian transgenesis, we find that the expression pattern of one of these genes, XNkx2-5, can be reproduced using transgenes containing only 4.3 kb of promoter sequence. Sequence analysis reveals remarkable conservation between the distalmost 300 bp of the Xenopus promoter and a portion of the AR2 element upstream of the mouse and human Nkx2-5 genes. Interestingly, only the 3' half of this evolutionarily conserved sequence element is required for correct transgene expression in frog embryos. Mutation of conserved GATA sites or a motif resembling the dpp-response element in the Drosophila tinman tinD enhancer dramatically reduces the levels of transgene expression. Finally we show that, despite its activity in Xenopus embryos, in transgenic mice the Xenopus Nkx2-5 promoter is able to drive reporter gene expression only in a limited subset of cells expressing the endogenous gene. This intriguing result suggests that despite evolutionary conservation of some cis-regulatory sequences, the regulatory controls on Nkx2-5 expression have diverged between mammals and amphibians.

Endotoxin-mediated nitric oxide synthesis inhibits IL-1beta gene transcription in ANA-1 murine macrophages

On the basis of previous work demonstrating nitric oxide (NO)-mediated inhibition of nuclear factor-kappaB (NF-kappaB) DNA binding, we hypothesized that NO downregulates NF-kappaB-dependent interleukin-1beta (IL-1beta) production in an ANA-1 macrophage model of lipopolysaccharide (LPS) stimulation. In the presence of LPS (100 ng/ml), levels of IL-1beta protein and mRNA were significantly upregulated with NO synthase inhibition. Using nuclear run-on analysis and transient transfection studies, IL-1beta gene transcription and IL-1beta promoter activity were also found to be increased with inhibition of NO production. Parallel transfection studies using an NF-kappaB long terminal repeat-reporter plasmid exhibited similar findings, suggesting an NO-mediated effect on NF-kappaB activity. Gel shift studies showed that LPS-associated NF-kappaB DNA binding was increased, both in the setting of NO synthase inhibition and in a reducing environment. Repletion of NO by addition of an S-nitrosothiol restored IL-1beta protein synthesis, mRNA levels, gene transcription, promoter activity, and NF-kappaB DNA binding to levels noted in the presence of LPS alone. Our studies indicate that NO may regulate LPS-associated inflammation by downregulating IL-1beta gene transcription through S-nitrosation of NF-kappaB.

Recombinant paramyosin (rec-Sj-97) tested for immunogenicity and vaccine efficacy against Schistosoma japonicum in mice and water buffaloes

A primary vaccine candidate antigen against schistosomiasis is paramyosin (pmy), a myofibrillar protein found exclusively in invertebrates. Here we report the results of vaccine trials against the Asian schistosome undertaken on inbred and outbred mice and water buffaloes using a bacterially expressed and purified form of Schistosoma japonicum pmy (rec-Sj-97). Vaccination of the mice resulted in high levels of specific anti-pmy IgG antibodies when compared with adjuvant controls and significant reduction in worm burdens and in liver eggs. Furthermore, a significant reduction in liver eggs was recorded in two of the three water buffalo vaccine trials undertaken and, in all three trials, high levels of specific anti-pmy IgG antibodies were generated. There was no evidence of any toxic effects and the vaccine preparations and Quil A adjuvant were clearly well tolerated. The development of a vaccine intended for livestock animals such as bovines would be beneficial in two ways; directly by blocking transmission of schistosomiasis to humans and economically by contributing to healthier livestock. We are encouraged by the consistent efficacy in the mouse and the buffalo vaccine trials that resulted in a significant decrease in liver eggs. Indeed, predictions from mathematical models indicate that an egg reduction effect of 42-45% in buffaloes would be sufficient when combined with human treatment to control schistosomiasis japonica in the marshes and lakes along the middle and upper reaches of the Yangtze River, the most highly endemic areas for the disease in China.

Androgen induces expression of the multidrug resistance protein gene MRP4 in prostate cancer cells

Multidrug resistance-associated proteins (MRPs) may mediate multidrug resistance in tumor cells. Using a gene array analysis, we have identified MRP4 as an androgen receptor (AR)-regulated gene. Dihydrotestosterone induced MRP4 expression in both androgen-dependent and -independent LNCaP cells, whereas there was little detectable expression in PC-3 or normal prostate epithelial cells. Disruption of MRP4 expression renders LNCaP cells more sensitive to the cytotoxic effects of methotrexate but not etoposide. Analysis of human tissues showed detectable MRP4 expression only in metastatic prostate cancer. These results suggest that AR induction of MRP4 mediates resistance of PC cells to nucleotide-based chemotherapeutic drugs.

A full-spectral Bayesian reconstruction approach based on the material decomposition model applied in dual-energy computed tomography

PURPOSE

Dual-energy computed tomography (DECT) makes it possible to get two fractions of basis materials without segmentation. One is the soft-tissue equivalent water fraction and the other is the hard-matter equivalent bone fraction. Practical DECT measurements are usually obtained with polychromatic x-ray beams. Existing reconstruction approaches based on linear forward models without counting the beam polychromaticity fail to estimate the correct decomposition fractions and result in beam-hardening artifacts (BHA). The existing BHA correction approaches either need to refer to calibration measurements or suffer from the noise amplification caused by the negative-log preprocessing and the ill-conditioned water and bone separation problem. To overcome these problems, statistical DECT reconstruction approaches based on nonlinear forward models counting the beam polychromaticity show great potential for giving accurate fraction images.

METHODS

This work proposes a full-spectral Bayesian reconstruction approach which allows the reconstruction of high quality fraction images from ordinary polychromatic measurements. This approach is based on a Gaussian noise model with unknown variance assigned directly to the projections without taking negative-log. Referring to Bayesian inferences, the decomposition fractions and observation variance are estimated by using the joint maximum a posteriori (MAP) estimation method. Subject to an adaptive prior model assigned to the variance, the joint estimation problem is then simplified into a single estimation problem. It transforms the joint MAP estimation problem into a minimization problem with a nonquadratic cost function. To solve it, the use of a monotone conjugate gradient algorithm with suboptimal descent steps is proposed.

RESULTS

The performance of the proposed approach is analyzed with both simulated and experimental data. The results show that the proposed Bayesian approach is robust to noise and materials. It is also necessary to have the accurate spectrum information about the source-detector system. When dealing with experimental data, the spectrum can be predicted by a Monte Carlo simulator. For the materials between water and bone, less than 5% separation errors are observed on the estimated decomposition fractions.

CONCLUSIONS

The proposed approach is a statistical reconstruction approach based on a nonlinear forward model counting the full beam polychromaticity and applied directly to the projections without taking negative-log. Compared to the approaches based on linear forward models and the BHA correction approaches, it has advantages in noise robustness and reconstruction accuracy.

Androgen regulation of soluble guanylyl cyclasealpha1 mediates prostate cancer cell proliferation

The growth and progression of prostate cancer are dependent on androgens and androgen receptor (AR), which act by modulating gene expression. Utilizing a gene microarray approach, we have identified the alpha1-subunit gene of soluble guanylyl cyclase (sGC) as a novel androgen-regulated gene. A heterodimeric cytoplasmic protein composed of one alpha and one beta subunit, sGC mediates the widespread cellular effects of nitric oxide (NO). We report here that, in prostate cancer cells, androgens stimulate the expression of sGCalpha1. A cloned human sGCalpha1 promoter is activated by androgen in an AR-dependent manner, suggesting that sGCalpha1 may be a direct AR target gene. Disruption of sGCalpha1 expression severely compromises the growth of both androgen-dependent and androgen-independent AR-positive prostate cancer cells. Overexpression of sGCalpha1 alone is sufficient for stimulating prostate cancer cell proliferation. Interestingly, the major growth effect of sGCalpha1 is independent of NO and cyclic guanosine monophosphate, a major mediator of the sGC enzyme. These data strongly suggest that sGCalpha1 acts in prostate cancer via a novel pathway that does not depend on sGCbeta1. Tissue studies show that sGCalpha1 expression is significantly elevated in advanced prostate cancer. Thus, sGCalpha1 may be an important mediator of the procarcinogenic effects of androgens.

Hindbrain herniation syndromes: the Chiari malformations (I and II)

Hindbrain hernias with or without hydrosyringomyelia were difficult diagnostic problems before the availability of magnetic resonance imaging. Today, the problem seems not to be in evaluating the anatomical extent of the caudal herniation of the cerebellum, but in determining which patient should be considered for operative intervention and the extent of the surgery. Chiari I patients are presenting at younger ages, occasionally with irritability as their only symptom. Should all of these children be submitted to an operation? Chiari II patients are now operated on with the first detectable symptom or evidence of a syrinx, and yet medullary dysfunction from the Chiari II malformation remains the leading cause of death in treated myelomeningoceles today. Our knowledge of the natural history of the untreated conditions and the increased safety of the operation has made surgical intervention a much more viable option for this group of patients.

Systems Pharmacology-Based Discovery of Natural Products for Precision Oncology Through Targeting Cancer Mutated Genes

Massive cancer genomics data have facilitated the rapid revolution of a novel oncology drug discovery paradigm through targeting clinically relevant driver genes or mutations for the development of precision oncology. Natural products with polypharmacological profiles have been demonstrated as promising agents for the development of novel cancer therapies. In this study, we developed an integrated systems pharmacology framework that facilitated identifying potential natural products that target mutated genes across 15 cancer types or subtypes in the realm of precision medicine. High performance was achieved for our systems pharmacology framework. In case studies, we computationally identified novel anticancer indications for several US Food and Drug Administration-approved or clinically investigational natural products (e.g., resveratrol, quercetin, genistein, and fisetin) through targeting significantly mutated genes in multiple cancer types. In summary, this study provides a powerful tool for the development of molecularly targeted cancer therapies through targeting the clinically actionable alterations by exploiting the systems pharmacology of natural products.