75 research outputs found
Clinical metabolomics identifies blood serum branched chain amino acids as potential predictive biomarkers for chronic graft vs. host disease
The allogeneic hematopoietic stem cell transplantation procedure-the only curative therapy for many types of hematological cancers-is increasing, and graft vs. host disease (GVHD) is the main cause of morbidity and mortality after transplantation. Currently, GVHD diagnosis is clinically performed. Whereas, biomarker panels have been developed for acute GVHD (aGVHD), there is a lack of information about the chronic form (cGVHD). Using nuclear magnetic resonance (NMR) and gas chromatography coupled to time-of-flight (GC-TOF) mass spectrometry, this study prospectively evaluated the serum metabolome of 18 Brazilian patients who had undergone allogeneic hematopoietic stem cell transplantation (HSCT). We identified and quantified 63 metabolites and performed the metabolomic profile on day -10, day 0, day +10 and day +100, in reference to day of transplantation. Patients did not present aGVHD or cGVHD clinical symptoms at sampling times. From 18 patients analyzed, 6 developed cGVHD. The branched-chain amino acids (BCAAs) leucine and isoleucine were reduced and the sulfur-containing metabolite (cystine) was increased at day +10 and day +100. The area under receiver operating characteristics (ROC) curves was higher than 0.79. BCAA findings were validated by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in 49 North American patients at day +100; however, cystine findings were not statistically significant in this patient set. Our results highlight the importance of multi-temporal and multivariate biomarker panels for predicting and understanding cGVHD9FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2011/06441-
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Ultrafiltration based purification strategies for surfactin produced by bacillus subtilis lb5a using cassava wastewater as substrate
BACKGROUND: Bacillus subtilis synthesizes surfactin, a powerful surface-active agent. It has interesting potential applications. However, due to its high cost of production, commercial use is impracticable. The downstream processing represents ≈60% of production costs and the culture medium ≈30%. Many reports focused, separately, on production of surfactin using by-products (reduced cost) or the purification using synthetic medium. Therefore, the aim of this work was to evaluate, for the first time, the impact of using a by-product as fermentation medium on the downstream processing based on membrane filtration.
RESULTS: Membranes of PES-100-kDa efficiently retained surfactin micelles - the first step of ultrafiltration, whereas, the second step required membranes of 50-kDa to separate surfactin monomers from proteins. Ultrafiltration of crude biosurfactant was associated with fouling and/or concentration polarization resulting in lower purity than when synthetic medium was used. Further improvement in purity was achieved by partial removal of proteins prior to ultrafiltration by precipitation and extraction. The RMN and MALDI-TOFMS analyses identified 11 potential surfactin homologous composed by two amino acid sequences.
CONCLUSION: Production of surfactin using cassava wastewater as a low-cost culture medium and its purification by the 2-step ultrafiltration process is feasible, nevertheless, the higher protein content of this medium as compared to the synthetic one leads to a lower purity product; further increase in purity can be achieved by applying additional purification steps prior to ultrafiltration with the subsequent increased in process cost
Synthesis and Characterization of Hybrid Materials Consisting of n-octadecyltriethoxysilane by Using n-Hexadecylamine as Surfactant and Q0 and T0 Cross-Linkers
Novel hybrid xerogel materials were synthesized by a sol-gel procedure. n-octadecyltriethoxysilane was co-condensed with and without different cross-linkers using Q0 and T0 mono-functionalized organosilanes in the presence of n-hexadecylamine with different hydroxyl silica functional groups at the surface. These polymer networks have shown new properties, for example, a high degree of cross-linking and hydrolysis. Two different synthesis steps were carried out: simple self-assembly followed by sol-gel transition and precipitation of homogenous sols. Due to the lack of solubility of these materials, the compositions of the new materials were determined by infrared spectroscopy, 13C and 29Si CP/MAS NMR spectroscopy and scanning electron microscopy
Immunological properties of Oxygen-Transport Proteins: Hemoglobin, Hemocyanin and Hemerythrin
Organic-inorganic membranes prepared from polyether diamine and epoxy silane
Organic-inorganic polymer membranes were prepared by reacting 3-glycidoxypropyl trimethoxysilane with diamines containing polyether segments, followed by hydrolysis and condensation with acid catalysis. The films were characterized by nuclear magnetic resonance and by dynamic mechanical analysis. The rigidity of the films increased with increasing epoxy content and also with addition of tetraethoxy silane (TEOS) to the reacting medium. Water absorption experiments showed that the diffusivity is decreased with increasing TEOS content. Membranes were evaluated for nanofiltration giving cut offs down to 860 g/mol (with a water flux of 2.5 l/h m(2) bar). For gas separation, CO2/N-2 selectivity values up to 89 were obtained with CO2 permeability of 125 Barrer. (C) 1999 Elsevier Science B.V. All rights reserved.1594167119720
DENSE HYDROPHILIC COMPOSITE MEMBRANES FOR ULTRAFILTRATION
Dense hydrophilic composite membranes for ultrafiltration were prepared from an asymmetric porous PVDF support coated with a thin (< 1 mu m) layer of polyether-block-polyamide copolymer. Membranes with a molecular weight cut-off between 800 and 4500 g/mol and water permeability between 2.3 and 9.4 1 h(-1) m(-2) bar(-1) were obtained. The dry membrane surface was characterized as a dense non-porous layer when observed by scanning electron microscopy. When compared to other commercial membranes and to the non-coated porous PVDF support in the ultrafiltration of oil-water waste, the performance of the composite membranes was comparable to the Amicon YM30 cellulose membrane with lower susceptibility to fouling.10641671495
Development of a chlorine-resistant polyamide nanofiltration membrane and its field-test results
Poly(dimethylsiloxane) networks modified with poly (phenylsilsesquioxane)s: Synthesis, structural characterisation and evaluation of the thermal stability and gas permeability
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Self-supported translucent films constituted of semi-inorganic polymeric materials were prepared by sol-gel process from poly(phenylsilsesquioxane) (PPSQ) and poly(dimethylsiloxane) (PDMS), modified by diphenylsilanediol (DPS), phenyltriethoxysilane (PTES) and/or tetraethoxysilane (TEOS). These materials were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA). Permeability to N-2, O-2, CH4 and CO2 and selectivity for a specific gas pair were investigated using the time-lag method. In the gas separation process high permeability and selectivity coefficients were observed, particularly for the membrane containing DPS and PTES as additives, which presented potential applications in the separation of CO2/CH4 and CO2/N-2. The materials also showed good thermal stability, which could be correlated to the relative amounts between di-functional (D), tri-functional (T) and tetra-functional (Q) silicon units. (c) 2008 Elsevier Ltd. All rights reserved.441030803086Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [03/09962-1]CNPq [305916/2006-8
Breast reconstruction: Correlation between different procedures, reconstruction timing and complications
Introduction. Improved psychophysical condition after breast reconstruction in women has been well documented Objective. To determine the most optimal technique with minimal morbidity, the authors examined their results and complications based on reconstruction timing (immediate and delayed reconstruction) and three reconstruction methods: TRAM flap, latissimus dorsi flap and reconstruction with tissue expanders and implants. Methods. Reconstruction was performed in 60 women of mean age 51.1 years. We analyzed risk factors: age, body mass index (BMI), smoking history and radiation therapy in correlation with timing and method of reconstruction. Complications of all three methods of reconstruction were under 1.5-2-year follow-up after the reconstruction. All data were statistically analyzed. Results. Only radiation had significant influence on the occurrence of complications both before and after the reconstruction, while age, smoking and BMI had no considerable influence of the development of complications. There were no statistically significant correlation between the incidence of complications, time and method of reconstruction. Conclusion. Any of the aforementioned breast reconstruction techniques can yield good results and a low rate of re-operations. To choose the best method, the patient needs to be as well informed as possible about the options including the risks and benefits of each method
Breast reconstruction: Correlation between different procedures, reconstruction timing and complications
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