1,124 research outputs found
Comparison of molecular typing methods for Candida albicans.
This is the published version. Copyright 1992 American Society for Microbiology.Four molecular approaches to determining the types of Candida albicans strains were compared. The strains used were those whose repeated DNA (ribosomal and mitochondrial) EcoRI restriction fragment length polymorphisms (RFLP) were determined by Stevens et al. (D. A. Stevens, F. C. Odds, and S. Scherer, Rev. Infect. Dis. 12:258-266, 1990). Scherer and Stevens (S. Scherer and D. A. Stevens, Proc. Natl. Acad. Sci. USA 85:1452-1456, 1988) used the same strains to examine the Southern blots of genomic EcoRI digests probed with the repeated sequence 27A. The results of these investigators were compared with determinations of RFLPs generated from repeated DNA by the enzyme HinfI and examination of the karyotypes of strains under two sets of conditions, one for the smaller chromosomes and one for the larger ones. Analysis of RFLPs of repeated DNA is most convenient but shows the lowest degree of resolution. Use of the repeated sequence and use of karyotype have very high resolution, but the former method is more convenient than the latter. HinfI digestion is more sensitive than EcoRI digestion but equally convenient. By using all four methods, separate types were identified for 18 of the 20 strains examined
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Influence of Controlled Epoxidation of an Asymmetric Styrene/Butadiene Star Block Copolymer on Structural and Mechanical Properties
The chemical modification (namely the epoxidation) of a star shaped block copolymer (BCP) based on polystyrene (PS) and polybutadiene (PB) and its effect on structural and mechanical properties of the polymer were investigated. Epoxidation degrees of 37 mol%, 58 mol%, and 82 mol% were achieved by the reaction of the copolymer with meta-chloroperoxy benzoic acid (m-CPBA) under controlled conditions. The BCP structure was found to change from lamellae-like to mixed-type morphologies for intermediate epoxidation level while leading to quite ordered cylindrical structures for the higher level of chemical modification. As a consequence, the glass transition temperature (Tg) of the soft PB component of the BCP shifted towards significantly higher temperature. A clear increase in tensile modulus and tensile strength with a moderate decrease in elongation at break was observed. The epoxidized BCPs are suitable as reactive templates for the fabrication of nanostructured thermosetting resins
Morphology and Tensile Properties of Multigraft Copolymers with Regularly Spaced Tri-, Tetra-, and Hexafunctional Junction Points
The effect of chain architecture on the morphological and tensile properties of series of multigraft copolymers, with regularly spaced tri-, tetra-, and hexafunctional junction points, was investigated using transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and tensile testing. The materials were synthesized by coupling difunctional polyisoprene (PI) spacers and living polystyrene (PS) branches, made by anionic polymerization, with chlorosilanes of different functionalities. Since the coupling process is a step-growth polymerization, yielding polydisperse products, fractionation was utilized to separate each material into three fractions (high, middle, and low molecular weight), each of low polydispersity. All three fractions have the same chain architecture on a per junction point basis but differ in the number of junction point units per molecule. By applying the constituting block copolymer concept, the physical behavior of these molecules was compared with current theories. It was found that morphological behavior of these graft copolymers can be predicted using theoretical approaches and is independent on the number of junction points. The number of the junction points, however, greatly influences the long-range order of microphase separation. Additionally, two new parameters for adjusting mechanical properties of multigraft copolymers were found in this investigation: (1) functionality of the graft copolymerstri-, tetra-, or hexafunctionals and (2) number of junction points per molecule. An increase in functionality causes a change in morphology, resulting in a high level of tensile strength for tetrafunctional (cylindrical) and hexafunctional (lamellae) multigraft copolymers, leading to about the twice the strength of the spherical trifunctional multigrafts of similar overall composition. Tetrafunctional multigraft copolymers show a surprisingly high strain at break, far exceeding that of commercial block copolymer thermoplastic elastomers (TPEs). Strain at break and tensile strength increase linearly with the number of junction points per molecule. Hysteresis experiments at about 300-900% deformation demonstrate that multifunctional multigraft copolymers have improved high elasticity as compared to commercial TPEs like Kraton or Styroflex
Effects of mometasone furoate/formoterol fumarate fixed-dose combination formulation on chronic obstructive pulmonary disease (COPD): results from a 52-week Phase III trial in subjects with moderate-to-very severe COPD
RATIONALE: The purpose of this study was to investigate the clinical efficacy and safety of a fixed-dose combination of mometasone furoate/formoterol fumarate (MF/F) administered via a metered-dose inhaler in subjects with moderate-to-very severe chronic obstructive pulmonary disease (COPD).
METHODS: This multicenter, double-blind, placebo-controlled trial had a 26-week treatment period and a 26-week safety extension. Subjects (n = 1196), at least 40 years old, were current or ex-smokers randomized to twice-daily inhaled MF/F 400/10 μg, MF/F 200/10 μg, MF 400 μg, F 10 μg, or placebo. The trial\u27s co-primary endpoints were mean changes from baseline, as area under the curve (AUC), in forced expiratory volume (FEV1) over 0-12 hours (AUC0-12 h FEV1) with MF/F versus MF, and in morning (AM) pre-dose (trough) FEV1 with MF/F versus F after 13 weeks of treatment. Key secondary endpoints were the effects of MF/F on respiratory health status using the Saint George\u27s Respiratory Questionnaire (SGRQ), symptom-free nights, partly stable COPD at 26 weeks, and time to first COPD exacerbation.
RESULTS: The largest improvements in AUC0-12 h FEV1 were observed with MF/F 400/10 μg and MF/F 200/10 μg. Serial spirometry results demonstrated that bronchodilator effects with MF/F occurred rapidly (within 5 minutes), persisted for 12 hours after dosing, and were sustained over the 26-week treatment period. Similar findings were observed for AM pre-dose FEV1, for which effects were further investigated, excluding subjects whose AM FEV1 data were incorrectly collected after 2 days from the last dose of study treatment. Improvements in SGRQ scores surpassed the minimum clinically important difference of more than four units with both MF/F treatments. At 26 weeks, no notable between-treatment differences in the occurrence and nature of adverse events (AEs) were reported. No unexpected AEs were observed. Overall, 90 subjects reported AEs considered to be treatment-related, the most common of which were lenticular opacities, dysphonia, and oral candidiasis.
DISCUSSION: In conclusion, MF/F treatments improved lung function and respiratory health status, reduced exacerbations, and were well tolerated in subjects with moderate-to-very severe COPD
Protein Targets of Thioacetamide Metabolites in Rat Hepatocytes
This document is the Accepted Manuscript version of a Published Work that appeared in final form in
Chemical Research in Toxicology, copyright © American Chemical Society after peer review and technical editing by the publisher.
To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/tx400001xThioacetamide (TA) has long been known as a hepatotoxicant whose bioactivation requires S-oxidation to thioacetamide S-oxide (TASO) and then to the very reactive S,S-dioxide (TASO2). The latter can tautomerize to form acylating species capable of covalently modifying cellular nucleophiles including phosphatidylethanolamine (PE) lipids and protein lysine side chains. Isolated hepatocytes efficiently oxidize TA to TASO but experience little covalent binding or cytotoxicity because TA is a very potent inhibitor of the oxidation of TASO to TASO2. On the other hand hepatocytes treated with TASO show extensive covalent binding to both lipids and proteins accompanied by extensive cytotoxicity. In this work, we treated rat hepatocytes with [14C]-TASO and submitted the mitochondrial, microsomal and cytosolic fractions to 2DGE which revealed a total of 321 radioactive protein spots. To facilitate the identification of target proteins and adducted peptides we also treated cells with a mixture of TASO/[13C2D3]-TASO. Using a combination of 1DGE- and 2DGE-based proteomic approaches, we identified 187 modified peptides (174 acetylated, 50 acetimidoylated and 37 in both forms) from a total of 88 non-redundant target proteins. Among the latter, 57 are also known targets of at least one other hepatotoxin. The formation of both amide- and amidine-type adducts to protein lysine side chains is in contrast to the exclusive formation of amidine-type adducts with PE phospholipids. Thiobenzamide (TB) undergoes the same two-step oxidative bioactivation as TA, and it also gives rise to both amide and amidine adducts on protein lysine side chains but only amidine adducts to PE lipids. Despite their similarity in functional group chemical reactivity, only 38 of 62 known TB target proteins are found among the 88 known targets of TASO. The potential roles of protein modification by TASO in triggering cytotoxicity are discussed in terms of enzyme inhibition, protein folding and chaperone function, and the emerging role of protein acetylation in intracellular signaling and the regulation of biochemical pathways
Efficacy and safety characteristics of mometasone furoate/formoterol fumarate fixed-dose combination in subjects with moderate to very severe COPD: findings from pooled analysis of two randomized, 52-week placebo-controlled trials
Background:
The clinical efficacy and safety of a mometasone furoate/formoterol fumarate (MF/F) fixed-dose combination formulation administered via a metered-dose inhaler was investigated in patients with moderate to very severe chronic obstructive pulmonary disease (COPD).
Methods:
Two 52-week, multicenter, double-blind, placebo-controlled trials with identical study designs were conducted in current or ex-smokers (aged =40 years), and pooled study results are presented herein. Subjects (n = 2251) were randomized to 26 weeks of twice-daily treatment with MF/F 400/10 µg, MF/F 200/10 µg, MF 400 µg, F 10 µg, or placebo. After the 26-week treatment period, placebo subjects completed the trial and 75% of subjects on active treatment entered a 26-week safety extension. Coprimary efficacy variables were mean changes in forced expiratory volume in one second (FEV1), area under the curve from 0 to 12 hours postdose (AUC0–12 h), and morning predose/trough FEV1 from baseline to the week 13 endpoint. Key secondary efficacy variables were St George’s Respiratory Questionnaire scores, symptom-free nights, time-to-first exacerbation, and partly stable COPD at the week 26 endpoint.
Results:
In the 26-week treatment period, significantly greater increases in FEV1 AUC0–12 h occurred with MF/F 400/10 versus MF 400 and placebo at the week 13 and week 26 endpoints (P = 0.032). These increases were over three-fold greater with MF/F 400/10 than with MF 400. Also, significantly greater increases in morning predose/trough FEV1 occurred with MF/F 400/10 versus F 10 and placebo at the week 13 endpoint (P \u3c 0.05). The increase was four-fold greater with MF/F 400/10 than with F 10. All active treatment groups achieved minimum clinically important differences from baseline (\u3e4 units) in St George’s Respiratory Questionnaire scores at week 26. Symptom-free nights increased by =14% in the MF/F 400/10, MF 400, and F 10 groups (P= 0.033 versus placebo). The incidence of exacerbations was lower in the MF/F groups (=33.3%) than it was in the MF, formoterol, and placebo groups (=33.8%) over the 26-week treatment period. The incidence of adverse events was similar in the active-treated and placebo-treated subjects across 26 weeks of treatment. Over the 1-year study period, there were no notable differences in the incidence or types of adverse events between the MF/F 400/10 and MF/F 200/10 groups compared with the MF or formoterol groups. Differences in rates of individual treatment-emergent adverse events were
Conclusion:
Patients treated with MF/F demonstrated significant improvements in lung function, health status, and exacerbation rates. Although significant improvements were seen with both doses, a trend showing a dose-response effect was observed in the lung function measurements
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