790 research outputs found
Alternate cyclin D1 mRNA splicing modulates P27\u3csup\u3eKlP1\u3c/sup\u3e binding and cell migration
Cyclin D1 is an important cell cycle regulator but in cancer its overexpression also increases cellular migration mediated by p27KlP1 stabilization and RhoA inhibition. Recently, a common polymorphism at the exon 4-intron 4 boundary of the human cyclin D1 gene within a splice donor region was associated with an altered risk of developing cancer. Altered RNA splicing caused by this polymorphism gives rise to a variant cyclin D1 isoform termed cyclin D1b, which has the same N-terminus as the canonical cyclin D1a isoform but a distinct C-terminus. In this study we show that these different isoforms have unique properties with regard to the cellular migration function of cyclin D1. Whereas they displayed little difference in transcriptional co-repression assays on idealized reporter genes, microarray cDNA expression analysis revealed differential regulation of genes including those that influence cellular migration. Additionally, while cyclin D1a stabilized p27KIP1 and inhibited RhoA-induced ROCK kinase activity, promoting cellular migration, cyclin D1b failed to stabilize p27KIP1 or inhibit ROCK kinase activity and had no effect on migration. Our findings argue that alternate splicing is an important determinant of the function of cyclin D1 in cellular migration
Anthelmintic Efficacy of Soluble Formulation of A Benzimidazole Carbamate A Broad Spectrum Anthelmintic
Methyl-[5-{(4-(2-pyridinyl)-1-piperazinyl)-carbonyl}-1H-benzimidazol-2-yl]-carbamate (CDRI Compound 81/470) has consistently exhibited broad-spectrum anthelmintic efficacy both against adult and larval stages of various helminth parasites of experimental and domestic animals, by oral and parenteral routes. The compound incorporated in transdermal tapes has also yielded anthelmintic action. With a view to enhance absorption and consequently the efficacy, a soluble formulation of the compound has been developed and its efficacy was evaluated against various experimental helminth parasites of rodents (Ancylostoma ceylanicum (adult), Nippostrongylus brasiliensis (adult and L_4), Syphacia obvelata (adult)) and poultry (Ascaridia galli). This appears to be the only benzimidazole which could be solubilized. While the soluble formulation has been found to have comparable efficacy to the powder form against intestinal worms, the efficacy was substantially increased against systemic parasites (N. brasiliensis L_4 stage). The enhanced efficacy by oral route is very well correlated with high absorption of drug from soluble formulation which has been demonstrated by the pharmacokinetic studies reported by Nagaraja et al. (1995). The results of the present study suggest that the soluble formulation may find wider application in respect to easy administration through drinking water in large herds, flocks and also against tissue dwelling parasites specially filarids
Quantum Correlations in NMR systems
In conventional NMR experiments, the Zeeman energy gaps of the nuclear spin
ensembles are much lower than their thermal energies, and accordingly exhibit
tiny polarizations. Generally such low-purity quantum states are devoid of
quantum entanglement. However, there exist certain nonclassical correlations
which can be observed even in such systems. In this chapter, we discuss three
such quantum correlations, namely, quantum contextuality, Leggett-Garg temporal
correlations, and quantum discord. In each case, we provide a brief theoretical
background and then describe some results from NMR experiments.Comment: 21 pages, 7 figure
A Novel Liquid Multi-Phytonutrient Supplement Demonstrates DNA-Protective Effects
This study explored the DNA protective (anti-mutagenic) effects of an oral, liquid, multi-phytonutrient dietary supplement containing a proprietary blend of fruits, vegetables and aloe vera concentrated components in addition to a proprietary catechin complex from green tea (VIBE Cardiac & Life, Eniva Nutraceuticals, Anoka, MN; herein described as āVIBEā). This study tested the hypothesis that VIBE would reduce DNA damage in skin cells exposed to UVR. Human epidermal cells, from the cell line A431NS, were treated with 0% (control), 0.125%, 0.5%, 1% and 2% VIBE, and then exposed to 240Ā J/m2 UVR. The amount of DNA damage was assessed using the COMET assay. At each concentration tested, a significantly smaller amount of DNA damage was measured by the COMET assay for the VIBE treated cells compared to the control cells exposed to UVR without VIBE. The dose response curves showed a maximal response at 0.5% VIBE with a threefold reduction in COMET tail density compared to the control samples without VIBE (pā<ā0.001). Additional research is warranted in human clinical trials to further explore the results of this study which demonstrated the DNA protective and anti-mutagenic effects of VIBE for human skin cells exposed to UVR-induced DNA damage
Substituted Methyl Benzimidazole Carbamate (CDRI Compound 81-470) in the Mass Treatment of Poultry Round Worms
Methyl 5 [4- (2-pyridinyl) -1- piperazinylcarbonyl] -1-H- benzimidazol -2- yl carbamate: (CDRI Comp. 81/470) has consistently exhibited broadspectrum anthelmintic efficacy both against adult and larval stages of various helminth parasites of experimental and domestic animals by oral or parenteral route. The compound incorporated in transdermal tape has also yielded anthelmintic action. In order to increase solubility and to make mass administration easier, two formulations e.g. soluble and dispersible, were prepared and found effective in control testing against various helminth parasites of rodents. Both the preparations were put to trial at 3 dose schedules to ascertain their utility for mass treatment of poultry carrying Ascaridia galli infection. Though the three dose schedule (20mg/kgx1, 10mg/kgx2, 5mg/kgx3 days) were found to have parallel efficacy, 5mg/kgx3 days dose requiring lesser compound than single administration was suggested useful in mass therapy. Thus, either of the preparations could be safely used for the control of poultry round-worms. However, the dispersible formulation having longer shelf-life and convenience of packaging and transportation may be preferred over the soluble preparation
Silymarin Targets Ī²-Catenin Signaling in Blocking Migration/Invasion of Human Melanoma Cells
Metastatic melanoma is a leading cause of death from skin diseases, and is often associated with activation of Wnt/Ī²-catenin signaling pathway. We have examined the inhibitory effect of silymarin, a plant flavanoid from Silybum marianum, on cell migration of metastasis-specific human melanoma cell lines (A375 and Hs294t) and assessed whether Wnt/Ī²-catenin signaling is the target of silymarin. Using an in vitro invasion assay, we found that treatment of human melanoma cell lines with silymarin resulted in concentration-dependent inhibition of cell migration, which was associated with accumulation of cytosolic Ī²-catenin, while reducing the nuclear accumulation of Ī²-catenin (i.e., Ī²-catenin inactivation) and reducing the levels of matrix metalloproteinase (MMP) -2 and MMP-9 which are the down-stream targets of Ī²-catenin. Silymarin enhanced: (i) the levels of casein kinase 1Ī±, glycogen synthase kinase-3Ī² and phosphorylated-Ī²-catenin on critical residues Ser45, Ser33/37 and Thr41, and (ii) the binding of Ī²-transducin repeat-containing proteins (Ī²-TrCP) with phospho forms of Ī²-catenin in melanoma cells. These events play important roles in degradation or inactivation of Ī²-catenin. To verify whether Ī²-catenin is a potent molecular target of silymarin, the effect of silymarin was determined on Ī²-catenin-activated (Mel 1241) and Ī²-catenin-inactivated (Mel 1011) melanoma cells. Treatment of Mel 1241 cells with silymarin or FH535, an inhibitor of Wnt/Ī²-catenin pathway, significantly inhibited cell migration of Mel 1241 cells, which was associated with the elevated levels of casein kinase 1Ī± and glycogen synthase kinase-3Ī², and decreased accumulation of nuclear Ī²-catenin and inhibition of MMP-2 and MMP-9 levels. However, this effect of silymarin and FH535 was not found in Mel 1011 melanoma cells. These results indicate for the first time that silymarin inhibits melanoma cell migration by targeting Ī²-catenin signaling pathway
Sunscreens - Which and what for?
It is well established that sun exposure is the main cause for the development of skin cancer. Chronic continuous UV radiation is believed to induce malignant melanoma, whereas intermittent high-dose UV exposure contributes to the occurrence of actinic keratosis as precursor lesions of squamous cell carcinoma as well as basal cell carcinoma. Not only photocarcinogenesis but also the mechanisms of photoaging have recently become apparent. In this respect the use of sunscreens seemed to prove to be more and more important and popular within the last decades. However, there is still inconsistency about the usefulness of sunscreens. Several studies show that inadequate use and incomplete UV spectrum efficacy may compromise protection more than previously expected. The sunscreen market is crowded by numerous products. Inorganic sunscreens such as zinc oxide and titanium oxide have a wide spectral range of activity compared to most of the organic sunscreen products. It is not uncommon for organic sunscreens to cause photocontact allergy, but their cosmetic acceptability is still superior to the one given by inorganic sunscreens. Recently, modern galenic approaches such as micronization and encapsulation allow the development of high-quality inorganic sunscreens. The potential systemic toxicity of organic sunscreens has lately primarily been discussed controversially in public, and several studies show contradictory results. Although a matter of debate, at present the sun protection factor (SPF) is the most reliable information for the consumer as a measure of sunscreen filter efficacy. In this context additional tests have been introduced for the evaluation of not only the protective effect against erythema but also protection against UV-induced immunological and mutational effects. Recently, combinations of UV filters with agents active in DNA repair have been introduced in order to improve photoprotection. This article reviews the efficacy of sunscreens in the prevention of epithelial and nonepithelial skin cancer, the effect on immunosuppression and the value of the SPF as well as new developments on the sunscreen market. Copyright (C) 2005 S. Karger AG, Basel
Graphene overcoats for ultra-high storage density magnetic media
Hard disk drives (HDDs) are used as secondary storage in digital electronic devices owing to low cost and large data storage capacity. Due to the exponentially increasing amount of data, there is a need to increase areal storage densities beyond~1Tb/in^2. This requires the thickness of carbon overcoats (COCs) to be<2 nm. However, friction, wear, corrosion, and thermal stability are critical concerns below 2 nm, limiting current technology, and restricting COC integration with heat assisted magnetic recording technology (HAMR). Here we show that graphene-based overcoats can overcome all these limitations, and achieve two-fold reduction in friction and provide better corrosion and wear resistance than state-of-the-art COCs, while withstanding HAMR conditions. Thus, we expect that graphene overcoats may enable the development of 4-10 Tb/in^2 areal density HDDs when employing suitable recording technologies, such as HAMR and HAMR+bit patterned media
Elastic and anelastic relaxation behaviour of perovskite multiferroics I: PbZr0.53Ti0.47O3(PZT)-PbFe0.5Nb0.5O3(PNF)
Perovskites in the ternary system PbTiO3 (PT)āPbZrO3 (PZ)āPb(Fe0.5Nb0.5)O3 (PFN) have attracted close interest because they can display simultaneous ferroelectric, magnetic and ferroelastic properties. Those with the most sensitive response to external fields are likely to have compositions near the morphotropic phase boundary (MPB) which lies close to the binary join Pb(Zr0.53Ti0.47)O3 (PZT)āPFN. In the present study, the strength and dynamics of strain coupling behaviour which accompanies the development of ferroelectricity and (anti)ferromagnetism in ceramic PZTāPFN samples have been investigated by resonant ultrasound spectroscopy. Elastic softening ahead of the cubicātetragonal transition does not fit with models based on dispersion of the soft mode or relaxor characteristics but is attributed, instead, to coupling between acoustic modes and a central peak mode from correlated relaxations and/or microstructure dynamics. Softening of the shear modulus through the transition by up to ~50 % fits with the expected pattern for linear/quadratic strain/order parameter coupling at an improper ferroelastic transition and close to tricritical evolution for the order parameter. Superattenuation of acoustic resonances in a temperature interval of ~100 K below the transition point is indicative of mobile ferroelastic twin walls. By way of contrast, the first-order tetragonalāmonoclinic transition involves only a small change in the shear modulus and is not accompanied by significant changes in acoustic dissipation. The dominant feature of the elastic and anelastic properties at low temperatures is a concave-up variation of the shear modulus and relatively high loss down to the lowest temperature, which appears to be the signature of materials with substantial local strain heterogeneity and a spectrum of strain relaxation times. No evidence of magnetoelastic coupling has been found, in spite of the samples displaying ferromagnetism below ~550 K and possible spin glass ordering below ~50 K. For the important multiferroic perovskite ceramics with compositions close to the MPB of ternary PT-PZ-PFN, there must be some focus in future on the role of strain heterogeneity
Elastic and anelastic relaxation behaviour of perovskite multiferroics II: PbZr0.53Ti0.47O3 (PZT)āPbFe0.5Ta0.5O3 (PFT)
Elastic and anelastic properties of ceramic samples of multiferroic perovskites with nominal compositions across the binary join PbZr0.53Ti0.47O3āPbFe0.5Ta0.5O3 (PZTāPFT) have been assembled to create a binary phase diagram and to address the role of strain relaxation associated with their phase transitions. Structural relationships are similar to those observed previously for PbZr0.53Ti0.47O3āPbFe0.5Nb0.5O3 (PZTāPFN), but the magnitude of the tetragonal shear strain associated with the ferroelectric order parameter appears to be much smaller. This leads to relaxor character for the development of ferroelectric properties in the end member PbFe0.5Ta0.5O3. As for PZTāPFN, there appear to be two discrete instabilities rather than simply a reorientation of the electric dipole in the transition sequence cubicātetragonalāmonoclinic, and the second transition has characteristics typical of an improper ferroelastic. At intermediate compositions, the ferroelastic microstructure has strain heterogeneities on a mesoscopic length scale and, probably, also on a microscopic scale. This results in a wide anelastic freezing interval for strain-related defects rather than the freezing of discrete twin walls that would occur in a conventional ferroelastic material. In PFT, however, the acoustic loss behaviour more nearly resembles that due to freezing of conventional ferroelastic twin walls. Precursor softening of the shear modulus in both PFT and PFN does not fit with a VogelāFulcher description, but in PFT there is a temperature interval where the softening conforms to a power law suggestive of the role of fluctuations of the order parameter with dispersion along one branch of the Brillouin zone. Magnetic ordering appears to be coupled only weakly with a volume strain and not with shear strain but, as with multiferroic PZTāPFN perovskites, takes place within crystals which have significant strain heterogeneities on different length scales
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