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Organic solvent nanofiltration (OSN) has been widely applied to separate and recycle homogeneous catalysts, but the influence of ligand and solvent selection on the performance of OSN is not fully understood. Here we prepared four palladium (Pd) catalysts by combining palladium acetate with four ligands of different molecular weights. Morphological and functional properties of the Pd catalysts were characterized by TEM, FTIR, and NMR. OSN experiments were conducted in a lab-scale dead-end filtration rig. Two commercial OSN membranes, PuraMem S600 (PS600) and DuraMem 500 (D500), were used to separate the Pd catalysts from different organic solvents (toluene, isopropanol, butanol/water, and methanol) that are specified to be compatible with, respectively. For both membranes, the pure solvent permeance was positively related to the degree of membrane swelling induced by the solvent. The solvent permeance decreased significantly after the addition of a solute, as a result of membrane fouling and concentration polarization. For the PS600 membrane, the Pd rejection in any solvent was closely correlated to the molecular weight of the ligand, which agrees with the pore-flow model. For the D500 membrane, on the other hand, there was no conclusive link between the Pd rejection and the type of ligand. The one-way analysis of variance (ANOVA) confirmed that the separation processes in PS600 and D500 membranes were controlled by different transport models. The findings shed light on the selection of ligand and solvent in OSN in order to enhance the separation of homogeneous catalysts.

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An improved, simple, effective and superior protocol has been developed to immobilize amano lipase from Pseudomonas fluorescens on woolen cloth using polyethyleneimine (PEI) with glutaraldehyde (GA) cross-linking. The success of immobilization was confirmed by FTIR and confocal laser scanning microscope (CLSM), the latter proving that enzyme is well distributed across the wool fiber surfaces throughout the cloth. Woolen cloth therefore provides a large outer and inner fiber surface area for immobilization with minimal mass transfer resistances during immobilization. The optimal protocol (GA at 0.5% and pH 6, lipase solution pH 6) gave an enzyme load of 46.6 mg g(-1)dry cloth with expressed activity of 178.3 U, 46.8% immobilization yield and 30.2% retained activity. Zeta potential measurements showed that PEI significantly enhanced the positive charge on woolen cloth and shifted the isoelectric point to approximately 7. Therefore at a lipase solution pH of around 6, the wool-PEI and lipase are oppositely charged, leading to a maximal adsorption of lipase to the wool surface. The immobilized lipase also had a good stability and 81% of its original activity was maintained after 10 runs in tributyrin emulsion hydrolysis. This protocol provides a significant improvement in terms of retained activity and lipase stability compared to previous immobilizations on wool and opens up the possibility of using wool as a cheap and effective lipase support material for continuous lipase reactions/reactors and possibly enzyme enhanced woolen fabrics.

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Myelodysplastic syndromes (MDSs) are a group of hematopoietic stem cell disorders characterized by ineffective hematopoiesis and peripheral blood cytopenias. Lenalidomide has dramatic therapeutic effects in patients with low-risk MDS and a chromosome 5q31 deletion, resulting in complete cytogenetic remission in >60% of patients. The molecular basis of this remarkable drug response is unknown. To gain insight into the molecular targets of lenalidomide we investigated its in vitro effects on growth, maturation, and global gene expression in isolated erythroblast cultures from MDS patients with del(5)(q31). Lenalidomide inhibited growth of differentiating del(5q) erythroblasts but did not affect cytogenetically normal cells. Moreover, lenalidomide significantly influenced the pattern of gene expression in del(5q) intermediate erythroblasts, with the VSIG4, PPIC, TPBG, activin A, and SPARC genes up-regulated by >2-fold in all samples and many genes involved in erythropoiesis, including HBA2, GYPA, and KLF1, down-regulated in most samples. Activin A, one of the most significant differentially expressed genes between lenalidomide-treated cells from MDS patients and healthy controls, has pleiotropic functions, including apoptosis of hematopoietic cells. Up-regulation and increased protein expression of the tumor suppressor gene SPARC is of particular interest because it is antiproliferative, antiadhesive, and antiangiogenic and is located at 5q31-q32, within the commonly deleted region in MDS 5q- syndrome. We conclude that lenalidomide inhibits growth of del(5q) erythroid progenitors and that the up-regulation of SPARC and activin A may underlie the potent effects of lenalidomide in MDS with del(5)(q31). SPARC may play a role in the pathogenesis of the 5q- syndrome.

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This Perspective highlights how the methodology of reaction progress kinetic analysis can provide a rapid and comprehensive kinetic profile of complex catalytic reaction networks under synthetically relevant conditions in a fraction of the number of experiments required by classical kinetic analysis. This approach relies on graphical manipulation of the extensive data sets available from accurate in situ monitoring of reaction progress under conditions where two concentration variables are changing simultaneously. A series of examples from Pd-catalyzed coupling reactions of aryl halides demonstrates how a wealth of kinetic information may be extracted from just three experiments in each case. Even before proposing a reaction mechanism, we can determine reaction orders in substrates, propose a resting state for the catalyst, and probe catalyst stability. Carrying out this kinetic analysis at the outset of a mechanistic investigation provides a framework for further work aimed at seeking a molecular-level understanding of the nature of the species within the catalytic cycle. To be considered plausible, any independent mechanistic proposal must be shown to be consistent with this global kinetic analysis.

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PURPOSE: Erythroid apoptosis in low-risk myelodysplastic syndrome (MDS) maybe mediated via mitochondrial release of cytochrome c and subsequent caspase activation. In the present study, we compared the in vitro and in vivo effects of proerythroid treatment with erythropoietin + granulocyte colony-stimulating factor (G-CSF) on myelodysplastic erythropoiesis regarding apoptosis and preferential growth of clones with cytogenetic abnormalities. EXPERIMENTAL DESIGN: We enrolled 15 refractory anemia (RA) and 11 refractory anemia with ringed sideroblasts (RARS), including 5q- aberration, monosomy 7, and trisomy 8, before initiation of treatment and followed nine patients after successful treatment. The effects of G-CSF and erythropoietin were assessed. The expression of G-CSF receptor (G-CSFR) was explored during erythroid maturation. The relative growth of erythroid progenitors with cytogenetic aberrations in presence of erythropoietin was investigated. RESULTS: Significant redistribution of cytochrome c was seen before treatment at all stages of erythroid differentiation. This release was blocked by G-CSF during the whole culture period and by erythropoietin during the latter phase. Both freshly isolated glycophorin A+ bone marrow cells and intermediate erythroblasts during cultivation retained their expression of G-CSFR. Cytochrome c release and caspase activation were significantly less pronounced in progenitors obtained from successfully treated nonanemic patients and showed no further response to G-CSF in vitro. Moreover, erythropoietin significantly promoted growth of cytogenetically normal cells from 5q- patients, whereas no such effect was observed on erythroblasts from monosomy 7 or trisomy 8 patients. CONCLUSION: We conclude that growth factors such as erythropoietin and G-CSF can act both via inhibition of apoptosis of myelodysplastic erythroid precursors and via selection of cytogenetically normal progenitors.

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The role of transcript variants of cyclin D1 in cancer biology is unclear. Most tumors with high levels of cyclin D1 express 2 transcripts due to alternative splicing: one full-length transcript of 4.4 kb and one short transcript of approximately 1.7 kb. The short transcript lacks part of the 3'UTR region regulating mRNA stability and has a longer half-life. In our study, the contribution of each of these mRNAs to gene expression and cell proliferation has been investigated in mantle cell lymphoma (MCL), a B cell lymphoma characterized by a specific gene translocation resulting in enhanced expression of cyclin D1. A subset of MCL tumors with low levels of the long cyclin D1 transcript (cyclin D1 3'UTR) was identified by quantitative PCR and by oligonucleotide array hybridization. This tumor-subset had 3.4-fold higher levels of the short form of cyclin D1 mRNA (p < 0.0001) and had higher expression of cyclin D1 protein. Gene expression analysis identified a number of cell-cycle regulatory genes as upregulated. There was a significant difference in frequencies of cyclin B1 (p = 0.0006) and cyclin A2 (p = 0.0006) positive cells that discriminated MCL with low cyclin D1 3'UTR from other highly proliferative MCL. Among differentially expressed genes, there was a highly upregulated gene with homology to the group of cell-cycle promoting E2F transcription partners, E2F_TDP5. Several of the upregulated genes, such as TOP2A, AURORA A and RRM2 may influence a response to therapy. Identification of MCL with low cyclin D1 3'UTR is important because it seems to be associated with shorter overall survival.

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