2,445 research outputs found
3,4,6-Tri-O-acetyl-2-(N-acetylacetamido )-1,2-dideoxy-o-Iyxohex- 1-enopyranose, an Acetamido-n-galactal Derivative, and the Mechanism of its Formation from 2-Acetamido-2-deoxy-D-galactose
The structure of an unsaturated amino sugar derivative, formed
in low yield when 2-acetamido-2-deoxy-o-galactose _is treated with
boiling isopropenyl acetate containing a trace of p-toluenesulfonic
acid, and formulated as 1,4,6-tri-0-acetyl-2-(N-acetylacetamido)-
2,3-dideoxy-o-threo-hex-2-enopyranose(II) in an earlier publication,
has been re-examined. Through a series of steps, including
catalytic hydrogenation, the substance has been converted into a
compound with an NMR spectrum which shows it to be 3,4,6-tri-
0-acetyl-2-(N -acetylbenzamido )-1,5-anhydro-2-deoxy-o-tali tol (X).
This fact, together with a re-examination of its NMR spectrum,
show the unsaturated compound to be 3,4,6-tri-0-acetyl-2-(N··
-acetylacetamido)-1,2-dideoxy-o-lyxo-hex-l-enopyranose (III), a
derivative of 2-acetamido-o-galactal (VI). The yield of III from
2-acetamido-2-deoxy-o-galactose has been substantially improved
through isolation of . 2-acetamido-1,3,4 , 6-tetra-0-acetyl-2-deoxy-~-
o-galactopyranose (XIII) as an intermediate and III has been
obtained in crystalline form. Evidence for the mechanism of its
formation is presented
The Behavior of 2-Acetamido-2-deoxy-o-galactose with Isopropenyl Acetate in the Presence of p-Toluenesulfonic Acid. Formation of an Unsaturated Aminosugar Derivative
Treatment of 2-acetamido-2-deoxy-n-galactose (III) with isopropenyl
acetate and p-toluenesulfonic acid gives 2-(n-glycero-1,2-
-diacetoxyethyl)-4-(N-acetylacetamido) furan (II), the anomeric 1,3,
4,6-te tra-O-acety 1- 2-(N -acetylacetamido )-2-d eoxy-o-gala ctopyranoses (IV and V), a mixture of the anomeric 1,3,5,6-te tra-0-acetyl-2- -(N-acetylacetamido) -2- deoxy-o-galactofuranoses (VII) and 1,4,6 - -tri -O-acetyl-2-(N-acetylacetamido)-2 ,3-dideoxy-o-threo-hex-2-enopyranose (X) . The anomeric 2-acetamido-1,3,4,6 -tetra-O-acetyl-2- -deo xy-n-galactopyranoses (VI) were also d etected ; they may be
primary products or artifacts arising from IV and V by spontaneous
de-N-acetylation in the course of the chromatography w hich was
used
3,4,6-Tri-O-acetyl-2-(N-acetylacetamido )-1,2-dideoxy-o-Iyxohex- 1-enopyranose, an Acetamido-n-galactal Derivative, and the Mechanism of its Formation from 2-Acetamido-2-deoxy-D-galactose
The structure of an unsaturated amino sugar derivative, formed
in low yield when 2-acetamido-2-deoxy-o-galactose _is treated with
boiling isopropenyl acetate containing a trace of p-toluenesulfonic
acid, and formulated as 1,4,6-tri-0-acetyl-2-(N-acetylacetamido)-
2,3-dideoxy-o-threo-hex-2-enopyranose(II) in an earlier publication,
has been re-examined. Through a series of steps, including
catalytic hydrogenation, the substance has been converted into a
compound with an NMR spectrum which shows it to be 3,4,6-tri-
0-acetyl-2-(N -acetylbenzamido )-1,5-anhydro-2-deoxy-o-tali tol (X).
This fact, together with a re-examination of its NMR spectrum,
show the unsaturated compound to be 3,4,6-tri-0-acetyl-2-(N··
-acetylacetamido)-1,2-dideoxy-o-lyxo-hex-l-enopyranose (III), a
derivative of 2-acetamido-o-galactal (VI). The yield of III from
2-acetamido-2-deoxy-o-galactose has been substantially improved
through isolation of . 2-acetamido-1,3,4 , 6-tetra-0-acetyl-2-deoxy-~-
o-galactopyranose (XIII) as an intermediate and III has been
obtained in crystalline form. Evidence for the mechanism of its
formation is presented
Use of low-dose oral theophylline as an adjunct to inhaled corticosteroids in preventing exacerbations of chronic obstructive pulmonary disease: study protocol for a randomised controlled trial.
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is associated with high morbidity, mortality, and health-care costs. An incomplete response to the anti-inflammatory effects of inhaled corticosteroids is present in COPD. Preclinical work indicates that 'low dose' theophylline improves steroid responsiveness. The Theophylline With Inhaled Corticosteroids (TWICS) trial investigates whether the addition of 'low dose' theophylline to inhaled corticosteroids has clinical and cost-effective benefits in COPD. METHOD/DESIGN: TWICS is a randomised double-blind placebo-controlled trial conducted in primary and secondary care sites in the UK. The inclusion criteria are the following: an established predominant respiratory diagnosis of COPD (post-bronchodilator forced expiratory volume in first second/forced vital capacity [FEV1/FVC] of less than 0.7), age of at least 40 years, smoking history of at least 10 pack-years, current inhaled corticosteroid use, and history of at least two exacerbations requiring treatment with antibiotics or oral corticosteroids in the previous year. A computerised randomisation system will stratify 1424 participants by region and recruitment setting (primary and secondary) and then randomly assign with equal probability to intervention or control arms. Participants will receive either 'low dose' theophylline (Uniphyllin MR 200 mg tablets) or placebo for 52 weeks. Dosing is based on pharmacokinetic modelling to achieve a steady-state serum theophylline of 1-5 mg/l. A dose of theophylline MR 200 mg once daily (or placebo once daily) will be taken by participants who do not smoke or participants who smoke but have an ideal body weight (IBW) of not more than 60 kg. A dose of theophylline MR 200 mg twice daily (or placebo twice daily) will be taken by participants who smoke and have an IBW of more than 60 kg. Participants will be reviewed at recruitment and after 6 and 12 months. The primary outcome is the total number of participant-reported COPD exacerbations requiring oral corticosteroids or antibiotics during the 52-week treatment period. DISCUSSION: The demonstration that 'low dose' theophylline increases the efficacy of inhaled corticosteroids in COPD by reducing the incidence of exacerbations is relevant not only to patients and clinicians but also to health-care providers, both in the UK and globally. TRIAL REGISTRATION: Current Controlled Trials ISRCTN27066620 was registered on Sept. 19, 2013, and the first subject was randomly assigned on Feb. 6, 2014
Span of control in supervision of rail track work
The supervision of engineering work on the railways has received relatively little examination despite being both safety-critical in its own right and having wider implications for the successful running of the railways. The present paper is concerned with understanding the factors that make different engineering works perceived as easier or harder to manage. We describe an approach building on notions of ‘span of control’, through which we developed the TOECAP inventory (Team, Organisation, Environment, Communication, Activity and Personal). This tool was validated through both interviews and questionnaires. As well as identifying the physical factors involved, the work also emphasised the importance of collaborative and attitudinal factors. We conclude by discussing limitations of the present work and future directions for development
Corticosterone Potentiation of Cocaine-Induced Reinstatement of Conditioned Place Preference in Mice is Mediated by Blockade of the Organic Cation Transporter 3
The mechanisms by which stressful life events increase the risk of relapse in recovering cocaine addicts are not well understood. We previously reported that stress, via elevated corticosterone, potentiates cocaine-primed reinstatement of cocaine seeking following self-administration in rats and that this potentiation appears to involve corticosterone-induced blockade of dopamine clearance via the organic cation transporter 3 (OCT3). In the present study, we use a conditioned place preference/reinstatement paradigm in mice to directly test the hypothesis that corticosterone potentiates cocaine-primed reinstatement by blockade of OCT3. Consistent with our findings following self-administration in rats, pretreatment of male C57/BL6 mice with corticosterone (using a dose that reproduced stress-level plasma concentrations) potentiated cocaine-primed reinstatement of extinguished cocaine-induced conditioned place preference. Corticosterone failed to re-establish extinguished preference alone but produced a leftward shift in the dose–response curve for cocaine-primed reinstatement. A similar potentiating effect was observed upon pretreatment of mice with the non-glucocorticoid OCT3 blocker, normetanephrine. To determine the role of OCT3 blockade in these effects, we examined the abilities of corticosterone and normetanephrine to potentiate cocaine-primed reinstatement in OCT3-deficient and wild-type mice. Conditioned place preference, extinction and reinstatement of extinguished preference in response to low-dose cocaine administration did not differ between genotypes. However, corticosterone and normetanephrine failed to potentiate cocaine-primed reinstatement in OCT3-deficient mice. Together, these data provide the first direct evidence that the interaction of corticosterone with OCT3 mediates corticosterone effects on drug-seeking behavior and establish OCT3 function as an important determinant of susceptibility to cocaine use
Exploratory analysis of a phase III trial of pirfenidone identifies a subpopulation of patients with idiopathic pulmonary fibrosis as benefiting from treatment
<p>Abstract</p> <p>Background</p> <p>A phase III trial in Japan showed that pirfenidone is effective for idiopathic pulmonary fibrosis (IPF). To find out which patients specifically benefit from pirfenidone, we analyzed in an exploratory manner the data from the phase III trial.</p> <p>Methods</p> <p>The patients in the phase III trial were stratified by baseline percentage predicted vital capacity (%VC), arterial oxygen partial pressure (PaO<sub>2</sub>), and the lowest oxygen saturation by pulse oximetry (SpO<sub>2</sub>) during the 6-minute steady-state exercise test (6MET). In the subpopulations, changes in VC and subjective symptoms (cough and dyspnea on the Fletcher, Hugh-Jones [F, H-J] Classification scale) were evaluated in patients treated with high-dose (1800 mg/day) pirfenidone, low-dose (1200 mg/day) pirfenidone, and placebo at week 52.</p> <p>Results</p> <p>Significant efficacy of pirfenidone in reducing the decline in VC could be seen in a subpopulation having %VC ≥ 70% and SpO<sub>2 </sub>< 90% at baseline. This favorable effect was accompanied by categorical change in VC and progression-free survival time. In the subpopulation, pirfenidone significantly suppressed cough and dyspnea.</p> <p>Conclusions</p> <p>IPF patients having %VC ≥ 70% and SpO<sub>2 </sub>< 90% at baseline will most likely benefit from pirfenidone when evaluated using changes in VC (and %VC), and cough and dyspnea symptoms. This subpopulation could expect to benefit most from pirfenidone treatment.</p> <p>Trial Registration</p> <p>This clinical trial was registered with the Japan Pharmaceutical Information Center (JAPIC) on September 13th, 2005 (Registration Number: JAPICCTI-050121).</p
Chaste: an open source C++ library for computational physiology and biology
Chaste - Cancer, Heart And Soft Tissue Environment - is an open source C++ library for the computational simulation of mathematical models developed for physiology and biology. Code development has been driven by two initial applications: cardiac electrophysiology and cancer development. A large number of cardiac electrophysiology studies have been enabled and performed, including high performance computational investigations of defibrillation on realistic human cardiac geometries. New models for the initiation and growth of tumours have been developed. In particular, cell-based simulations have provided novel insight into the role of stem cells in the colorectal crypt. Chaste is constantly evolving and is now being applied to a far wider range of problems. The code provides modules for handling common scientific computing components, such as meshes and solvers for ordinary and partial differential equations (ODEs/PDEs). Re-use of these components avoids the need for researchers to "re-invent the wheel" with each new project, accelerating the rate of progress in new applications. Chaste is developed using industrially-derived techniques, in particular test-driven development, to ensure code quality, re-use and reliability. In this article we provide examples that illustrate the types of problems Chaste can be used to solve, which can be run on a desktop computer. We highlight some scientific studies that have used or are using Chaste, and the insights they have provided. The source code, both for specific releases and the development version, is available to download under an open source Berkeley Software Distribution (BSD) licence at http://www.cs.ox.ac.uk/chaste, together with details of a mailing list and links to documentation and tutorials
Genetic Variants at Chromosomes 2q35, 5p12, 6q25.1, 10q26.13, and 16q12.1 Influence the Risk of Breast Cancer in Men
Male breast cancer accounts for approximately 1% of all breast cancer. To date, risk factors for male breast cancer are poorly defined, but certain risk factors and genetic features appear common to both male and female breast cancer. Genome-wide association studies (GWAS) have recently identified common single nucleotide polymorphisms (SNPs) that influence female breast cancer risk; 12 of these have been independently replicated. To examine if these variants contribute to male breast cancer risk, we genotyped 433 male breast cancer cases and 1,569 controls. Five SNPs showed a statistically significant association with male breast cancer: rs13387042 (2q35) (odds ratio (OR) = 1.30, p = 7.98×10−4), rs10941679 (5p12) (OR = 1.26, p = 0.007), rs9383938 (6q25.1) (OR = 1.39, p = 0.004), rs2981579 (FGFR2) (OR = 1.18, p = 0.03), and rs3803662 (TOX3) (OR = 1.48, p = 4.04×10−6). Comparing the ORs for male breast cancer with the published ORs for female breast cancer, three SNPs—rs13387042 (2q35), rs3803662 (TOX3), and rs6504950 (COX11)—showed significant differences in ORs (p<0.05) between sexes. Breast cancer is a heterogeneous disease; the relative risks associated with loci identified to date show subtype and, based on these data, gender specificity. Additional studies of well-defined patient subgroups could provide further insight into the biological basis of breast cancer development
Threat-sensitive anti-predator defence in precocial wader, the northern lapwing Vanellus vanellus
Birds exhibit various forms of anti-predator behaviours to avoid reproductive failure, with mobbing—observation, approach and usually harassment of a predator—being one of the most commonly observed. Here, we investigate patterns of temporal variation in the mobbing response exhibited by a precocial species, the northern lapwing (Vanellus vanellus). We test whether brood age and self-reliance, or the perceived risk posed by various predators, affect mobbing response of lapwings. We quantified aggressive interactions between lapwings and their natural avian predators and used generalized additive models to test how timing and predator species identity are related to the mobbing response of lapwings. Lapwings diversified mobbing response within the breeding season and depending on predator species. Raven Corvus corax, hooded crow Corvus cornix and harriers evoked the strongest response, while common buzzard Buteo buteo, white stork Ciconia ciconia, black-headed gull Chroicocephalus ridibundus and rook Corvus frugilegus were less frequently attacked. Lapwings increased their mobbing response against raven, common buzzard, white stork and rook throughout the breeding season, while defence against hooded crow, harriers and black-headed gull did not exhibit clear temporal patterns. Mobbing behaviour of lapwings apparently constitutes a flexible anti-predator strategy. The anti-predator response depends on predator species, which may suggest that lapwings distinguish between predator types and match mobbing response to the perceived hazard at different stages of the breeding cycle. We conclude that a single species may exhibit various patterns of temporal variation in anti-predator defence, which may correspond with various hypotheses derived from parental investment theory
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