Partial characterization and anticoagulant activity of a heterofucan from the brown seaweed Padina gymnospora

The brown algae Padina gymnospora contain different fucans. Powdered algae were submitted to proteolysis with the proteolytic enzyme maxataze. The first extract of the algae was constituted of polysaccharides contaminated with lipids, phenols, etc. Fractionation of the fucans with increasing concentrations of acetone produced fractions with different proportions of fucose, xylose, uronic acid, galactose, and sulfate. One of the fractions, precipitated with 50% acetone (v/v), contained an 18-kDa heterofucan (PF1), which was further purified by gel-permeation chromatography on Sephadex G-75 using 0.2 M acetic acid as eluent and characterized by agarose gel electrophoresis in 0.05 M 1,3 diaminopropane/acetate buffer at pH 9.0, methylation and nuclear magnetic resonance spectroscopy. Structural analysis indicates that this fucan has a central core consisting mainly of 3-ß-D-glucuronic acid 1-> or 4-ß-D-glucuronic acid 1 ->, substituted at C-2 with alpha-L-fucose or ß-D-xylose. Sulfate groups were only detected at C-3 of 4-alpha-L-fucose 1-> units. The anticoagulant activity of the PF1 (only 2.5-fold lesser than low molecular weight heparin) estimated by activated partial thromboplastin time was completely abolished upon desulfation by solvolysis in dimethyl sulfoxide, indicating that 3-O-sulfation at C-3 of 4-alpha-L-fucose 1-> units is responsible for the anticoagulant activity of the polymer.Universidade Federal do Rio Grande do Norte Departamento de Bioquímica Laboratório de GlicobiologiaUniversidade Federal do Rio Grande do Norte Departamento de Bioquímica Laboratório de Biotecnologia de Polímeros NaturaisUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de BioquímicaUNIFESP, EPM, Depto. de BioquímicaSciEL

The association of AGTR2 polymorphisms with preeclampsia and uterine artery bilateral notching is modulated by maternal BMI

On behalf of the SCOPE consortiumIntroductionThis study aimed to determine the association of AGTR1 and AGTR2 polymorphisms with preeclampsia and whether these are affected by environmental factors and fetal sex.MethodsOverall 3234 healthy nulliparous women, their partners and babies were recruited prospectively to the SCOPE study in Adelaide and Auckland. Data analyses were confined to 2121 Caucasian parent-infant trios, among whom 123 had preeclamptic pregnancies. 1185 uncomplicated pregnancies served as controls. DNA was extracted from buffy coats and genotyped by utilizing the Sequenom MassARRAY system. Doppler sonography on the uterine arteries was performed at 20 weeks' gestation.ResultsFour polymorphisms in AGTR1 and AGTR2 genes, including AGTR1 A1166C, AGTR2 C4599A, AGTR2 A1675G and AGTR2 T1134C, were selected and significant associations were predominately observed for AGTR2 C4599A. When the cohort was stratified by maternal BMI, in women with BMI ≥ 25 kg/m(2), the AGTR2 C4599A AA genotype in mothers and neonates was associated with an increased risk for preeclampsia compared with the CC genotype [adjusted OR 2.1 (95% CI 1.0-4.2) and adjusted OR 3.0 (95% CI 1.4-6.4), respectively]. In the same subset of women, paternal AGTR2 C4599A A allele was associated with an increased risk for preeclampsia and uterine artery bilateral notching at 20 weeks' gestation compared with the C allele [adjusted OR 1.9 (95% CI 1.1-3.3) and adjusted OR 2.1 (95% CI 1.3-3.4), respectively].ConclusionAGTR2 C4599A in mothers, fathers and babies was associated with preeclampsia and this association was only apparent in pregnancies in which the women had a BMI ≥ 25 kg/m(2), suggesting a gene-environment interaction.A. Zhou, G.A. Dekker, E.R. Lumbers, S.Y. Lee, S.D. Thompson, L.M.E. McCowan, C.T. Robert

Effects of flavomycin on ruminal fermentation, In situ degradability and In vivo digestibility in bovine fed sugarcane diets

Problem statement: The aim of the present study was to characterize and differentiate the effects of addition of flavomycin or monensin on ruminal fermentation and degradability as well as on total digestibility in bovine. Approach: Twelve non-pregnant and non-lactating cows (736 kg of BW) were randomly assigned to three treatments: control, flavomycin (20 mg animal-1 day-1) and monensin (300 mg animal-1 day-1). The trial lasted 21 days. The last 10 days were used for external marker administration (15 g of chromic oxide animal-1 day-1). The last 5 days of the trial were used for feces collection and evaluation of corn grain, soybean meal or sugarcane ruminal degradability and the 21st day was used for ruminal fluid sampling. Results: Monensin increased 27.2%, on average, propionate molar proportion at 0, 4, 6, 8, 10 and 12 h after feeding, compared to control and flavomycin groups. When compared to control, flavomycin reduced the degradation rate of soybean meal CP in 31.0%, decreasing the effective degradability when passage rates of 5 and 8% h-1 were used. Dry matter intake, pH, total Short Chain Fatty Acids (tSCFA) or ammoniacal Nitrogen (NH3-N) concentration were not influenced by the addition of either antibiotics. Effective degradability of sugarcane NDF was not influenced by the use of either antibiotic; neither were the TDN nor the digestibility of DM, CP, EE, NFE, ADF, NDF, GE or starch of the diet. Conclusion/Recommendations: In the present study, it was possible to show the beneficial effects of monensin but not of flavomycin, on rumen fermentationFundação de Amparo à Pesquisa do Estado de São Paul

Molecular beam epitaxy as a growth technique for achieving free-standing zinc-blende GaN and wurtzite AlxGa1-xN

Currently there is a high level of interest in the development of ultraviolet (UV) light sources for solid state lighting, optical sensors, surface decontamination and water purification. III-V semiconductor UV LEDs are now successfully manufactured using the AlGaN material system; however, their efficiency is still low. The majority of UV LEDs require AlxGa1-xN layers with compositions in the mid-range between AlN and GaN. Because there is a significant difference in the lattice parameters of GaN and AlN, AlxGa1-xN substrates would be preferable to those of either GaN or AlN for many ultraviolet device applications. However, the growth of AlxGa1-xN bulk crystals by any standard bulk growth techniques has not been developed so far. There are very strong electric polarization fields inside the wurtzite (hexagonal) group III-nitride structures. The charge separation within quantum wells leads to a significant reduction in the efficiency of optoelectronic device structures. Therefore, the growth of non-polar and semi-polar group III-nitride structures has been the subject of considerable interest recently. A direct way to eliminate polarization effects is to use non-polar (001) zinc-blende (cubic) III-nitride layers. However, attempts to grow zinc-blende GaN bulk crystals by anystandard bulk growth techniques were not successful. Molecular beam epitaxy (MBE) is normally regarded as an epitaxial technique for the growth of very thin layers with monolayer control of their thickness. In this study we have used plasma-assisted molecular beam epitaxy (PA MBE) and have produced for the first time free-standing layers of zinc-blende GaN up to 100 μm in thickness and up to 3-inch in diameter. We have shown that our newly developed PA-MBE process for the growth of zinc-blende GaN layers can also be used to achieve free-standing wurtzite AlxGa1-xN wafers. Zinc-blende and wurtzite AlxGa1-xN polytypes can be grown on different orientations of GaAs substrates - (001) and (111)B respectively. We have subsequently removed the GaAs using a chemical etch in order to produce free-standing GaN and AlxGa1-xN wafers. At a thickness of ∼30 μm, free-standing GaN and AlxGa1-xN wafers can easily be handled without cracking. Therefore, free-standing GaN and AlxGa1-xN wafers with thicknesses in the 30–100 μm range may be used as substrates for further growth of GaN and AlxGa1 xN-based structures and devices. We have compared different RF nitrogen plasma sources for the growth of thick nitride AlxGa1-xN films including a standard HD25 source from Oxford Applied Research and a novel high efficiency source from Riber. We have investigated a wide range of the growth rates from 0.2 to 3 μm/h. The use of highly efficient nitrogen RF plasma sources makes PA-MBE a potentially viable commercial process, since free-standing films can be achieved in a single day. Our results have demonstrated that MBE may be competitive with the other group III-nitrides bulk growth techniques in several important areas including production of free-standing zinc-blende (cubic) (Al)GaN and of free-standing wurtzite (hexagonal) AlGaN

Characteristics of specialists treating hypothyroid patients:the “THESIS” collaborative

Introduction: Thyroid specialists influence how hypothyroid patients are treated, including patients managed in primary care. Given that physician characteristics influence patient care, this study aimed to explore thyroid specialist profiles and associations with geo-economic factors. Methods: Thyroid specialists from 28 countries were invited to respond to a questionnaire, Treatment of Hypothyroidism in Europe by Specialists: an International Survey (THESIS). Geographic regions were defined according to the United Nations Statistics Division. The national economic status was estimated using World Bank data on the gross national income per capita (GNI per capita). Results: 5,695 valid responses were received (response rate 33·0%). The mean age was 49 years, and 65·0% were female. The proportion of female respondents was lowest in Northern (45·6%) and highest in Eastern Europe (77·2%) (p &lt;0·001). Respondent work volume, university affiliation and private practice differed significantly between countries (p&lt;0·001). Age and GNI per capita were correlated inversely with the proportion of female respondents (p&lt;0·01). GNI per capita was inversely related to the proportion of respondents working exclusively in private practice (p&lt;0·011) and the proportion of respondents who treated &gt;100 patients annually (p&lt;0·01). Discussion: THESIS has demonstrated differences in characteristics of thyroid specialists at national and regional levels, strongly associated with GNI per capita. Hypothyroid patients in middle-income countries are more likely to encounter female thyroid specialists working in private practice, with a high workload, compared to high-income countries. Whether these differences influence the quality of care and patient satisfaction is unknown, but merits further study.</p

7th Drug hypersensitivity meeting: part two

No abstract availabl