75 research outputs found
Vortex Fluctuations in High-Tc Films: Flux Noise Spectrum and Complex Impedance
The flux noise spectrum and complex impedance for a 500 {\AA} thick YBCO film
are measured and compared with predictions for two dimensional vortex
fluctuations. It is verified that the complex impedance and the flux noise
spectra are proportional to each other, that the logarithm of the flux noise
spectra for different temperatures has a common tangent with slope , and that the amplitude of the noise decreases as , where is
the height above the film at which the magnetic flux is measured. A crossover
from normal to anomalous vortex diffusion is indicated by the measurements and
is discussed in terms of a two-dimensional decoupling.Comment: 5 pages including 4 figures in two columns, to appear in Phys. Rev.
Let
Assessing ecological risks and benefits of genetically modified crops 99
Abstract: Genetically modified (GM) crops and biotechnology are providing new opportunities for increasing crop productivity and tackling agriculture problems, such as diseases, pests and weeds, abiotic stress and nutritional limitations of staple food crops. As GM crops are being adopted in various locations with different ecosystems, a scientifically based understanding of the environmental effects of cultivations of GM crops would assist decision makers worldwide in ensuring environmental safety and sustainability. In this paper are discussed some of the most important problems related to the GM crops into the environment such as: plant protection, hybridisation, ecological effects of HRCs, gene flow, biodiversity, stress, ecological risks (ERA), effects on the soil ecosystem etc
Search for α3β2/3γ2 subtype selective ligands that are stable on human liver microsomes
Selective modulation of specific benzodiazepine receptor (BzR) gamma amino butyric acid-A (GABAA) receptor ion channels has been identified as an important method for separating out the variety of pharmacological effects elicited by BzR-related drugs. Importantly, it has been demonstrated that both α2β(2/3)γ2 (α2BzR) and α3BzR (and/or α2/α3) BzR subtype selective ligands exhibit anxiolytic effects with little or no sedation. Previously we have identified several such ligands; however, three of our parent ligands exhibited significant metabolic liability in rodents in the form of a labile ester group. Here eight analogs are reported which were designed to circumvent this liability by utilizing a rational replacement of the ester moiety based on medicinal chemistry precedents. In a metabolic stability study using human liver microsomes, four compounds were found to undergo slower metabolic transformation, as compared to their corresponding ester analogs. These compounds were also evaluated in in vitro binding as well as efficacy assays. Additionally, bioisostere 11 was evaluated in a rodent model of anxiety. It exhibited anxiolytic activity at doses of 10 and 100 mg/kg and was devoid of sedative properties
Role of Cajal Bodies and Nucleolus in the Maturation of the U1 snRNP in Arabidopsis
Background: The biogenesis of spliceosomal snRNPs takes place in both the cytoplasm where Sm core proteins are added and snRNAs are modified at the 59 and 39 termini and in the nucleus where snRNP-specific proteins associate. U1 snRNP consists of U1 snRNA, seven Sm proteins and three snRNP-specific proteins, U1-70K, U1A, and U1C. It has been shown previously that after import to the nucleus U2 and U4/U6 snRNP-specific proteins first appear in Cajal bodies (CB) and then in splicing speckles. In addition, in cells grown under normal conditions U2, U4, U5, and U6 snRNAs/snRNPs are abundant in CBs. Therefore, it has been proposed that the final assembly of these spliceosomal snRNPs takes place in this nuclear compartment. In contrast, U1 snRNA in both animal and plant cells has rarely been found in this nuclear compartment. Methodology/Principal Findings: Here, we analysed the subnuclear distribution of Arabidopsis U1 snRNP-specific proteins fused to GFP or mRFP in transiently transformed Arabidopsis protoplasts. Irrespective of the tag used, U1-70K was exclusively found in the nucleus, whereas U1A and U1C were equally distributed between the nucleus and the cytoplasm. In the nucleus all three proteins localised to CBs and nucleoli although to different extent. Interestingly, we also found that the appearance of the three proteins in nuclear speckles differ significantly. U1-70K was mostly found in speckles whereas U1A and U1C in,90 % of cells showed diffuse nucleoplasmic in combination with CBs and nucleolar localisation. Conclusions/Significance: Our data indicate that CBs and nucleolus are involved in the maturation of U1 snRNP. Difference
The importance of myo-inositol and D-chiro-inositol to support fertility and reproduction
This review details the physiologic roles of two insulin sensitizers, myo-inositol (MI) and D-chiro-inositol (DCI). In the human ovary, MI is a second messenger of follicle stimulating hormone (FSH) and DCI is an aromatase inhibitor. These activities allow a treatment for polycystic ovary syndrome (PCOS) to be defined based on the combined administration of MI and DCI, where the best MI:DCI ratio is 40:1. In addition, MI plays a pivotal role in the physiology of reproduction, and has beneficial effects on the development of oocytes, spermatozoa, and embryos. By contrast, DCI has little effect on spermatozoa, but high concentrations in the ovary can negatively affect the quality of oocytes and the blastocyst. Overall, the evidence in the literature supports the beneficial effects of MI in both female and male reproduction, warranting clinical use of MI in assisted reproductive treatment (ART).Cette revue détaille les rôles physiologiques de deux sensibilisateurs à l'insuline, le myo-inositol (MI) et le D-chiro-inositol (DCI). Dans l'ovaire humain, le MI est un second messager de l'hormone folliculostimulante (FSH) et le DCI est un inhibiteur de l'aromatase. Ces activités permettent de définir un traitement du syndrome des ovaires polykystiques (SOPK) basé sur l'administration combinée de MI et de DCI, où le meilleur rapport MI:DCI est de 40:1. En outre, le MI joue un rôle essentiel dans la physiologie de la reproduction et a des effets bénéfiques sur le développement des ovocytes, des spermatozoïdes et des embryons. En revanche, le DCI a peu d'effet sur les spermatozoïdes, mais des concentrations élevées dans l'ovaire peuvent avoir un effet négatif sur la qualité des ovocytes et du blastocyste. Dans l'ensemble, les données de la littérature confirment les effets bénéfiques du MI dans la reproduction féminine et masculine, ce qui justifie l'utilisation clinique du MI dans l'assistance médicale à la procréation
Presence of activating KRAS mutations correlates significantly with expression of tumour suppressor genes DCN and TPM1 in colorectal cancer
<p>Abstract</p> <p>Background</p> <p>Despite identification of the major genes and pathways involved in the development of colorectal cancer (CRC), it has become obvious that several steps in these pathways might be bypassed by other as yet unknown genetic events that lead towards CRC. Therefore we wanted to improve our understanding of the genetic mechanisms of CRC development.</p> <p>Methods</p> <p>We used microarrays to identify novel genes involved in the development of CRC. Real time PCR was used for mRNA expression as well as to search for chromosomal abnormalities within candidate genes. The correlation between the expression obtained by real time PCR and the presence of the <it>KRAS </it>mutation was investigated.</p> <p>Results</p> <p>We detected significant previously undescribed underexpression in CRC for genes <it>SLC26A3</it>, <it>TPM1 </it>and <it>DCN</it>, with a suggested tumour suppressor role. We also describe the correlation between <it>TPM1 </it>and <it>DCN </it>expression and the presence of <it>KRAS </it>mutations in CRC. When searching for chromosomal abnormalities, we found deletion of the <it>TPM1 </it>gene in one case of CRC, but no deletions of <it>DCN </it>and <it>SLC26A3 </it>were found.</p> <p>Conclusion</p> <p>Our study provides further evidence of decreased mRNA expression of three important tumour suppressor genes in cases of CRC, thus implicating them in the development of this type of cancer. Moreover, we found underexpression of the <it>TPM1 </it>gene in a case of CRCs without <it>KRAS </it>mutations, showing that <it>TPM1 </it>might serve as an alternative path of development of CRC. This downregulation could in some cases be mediated by deletion of the <it>TPM1 </it>gene. On the other hand, the correlation of <it>DCN </it>underexpression with the presence of <it>KRAS </it>mutations suggests that <it>DCN </it>expression is affected by the presence of activating <it>KRAS </it>mutations, lowering the amount of the important tumour suppressor protein decorin.</p
Central Action of Peripherally Applied Botulinum Toxin Type A on Pain and Dural Protein Extravasation in Rat Model of Trigeminal Neuropathy
BACKGROUND:
Infraorbital nerve constriction (IoNC) is an experimental model of trigeminal neuropathy. We investigated if IoNC is accompanied by dural extravasation and if botulinum toxin type A (BoNT/A) can reduce pain and dural extravasation in this model. ----- METHODOLOGY/PRINCIPAL FINDINGS:
Rats which developed mechanical allodynia 14 days after the IoNC were injected with BoNT/A (3.5 U/kg) into vibrissal pad. Allodynia was tested by von Frey filaments and dural extravasation was measured as colorimetric absorbance of Evans blue - plasma protein complexes. Presence of dural extravasation was also examined in orofacial formalin-induced pain. Unilateral IoNC, as well as formalin injection, produced bilateral dural extravasation. Single unilateral BoNT/A injection bilaterally reduced IoNC induced dural extravasation, as well as allodynia (lasting more than 2 weeks). Similarly, BoNT/A reduced formalin-induced pain and dural extravasation. Effects of BoNT/A on pain and dural extravasation in IoNC model were dependent on axonal transport through sensory neurons, as evidenced by colchicine injections (5 mM, 2 µl) into the trigeminal ganglion completely preventing BoNT/A effects. ----- CONCLUSIONS/SIGNIFICANCE:
Two different types of pain, IoNC and formalin, are accompanied by dural extravasation. The lasting effect of a unilateral injection of BoNT/A in experimental animals suggests that BoNT/A might have a long-term beneficial effect in craniofacial pain associated with dural neurogenic inflammation. Bilateral effects of BoNT/A and dependence on retrograde axonal transport suggest a central site of its action
Canagliflozin and renal outcomes in type 2 diabetes and nephropathy
BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years
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