Preparation and Characterization of Polyvinylalcohol/Polysulfone Composite Membranes for Enhanced CO2/N2 Separation.

The unique properties of polyvinyl alcohol (PVA) and polysulfone (PSf), such as good membrane-forming ability and adjustable structure, provide a great opportunity for CO2-separation membrane development. This work focuses on the fabrication of PVA/PSf composite membranes for CO2/N2 separations. The membranes prepared by coating a 7.5 wt% PVA on top of PSf substrate showed a relatively thin selective layer of 1.7 µm with an enhanced CO2/N2 selectivity of 78, which is a ca. 200% increase compared to the pure PSf membranes. The CO2/N2 selectivity decreases at a rapid rate with the increase of feed pressure from 1.8 to 5 bar, while the CO2 permeance shows a slight reduction, which is caused by the weakening of coupling transportation between water and CO2 molecules, as well as membrane compaction at higher pressures. Increasing operating temperature from 22 °C to 50 °C leads to a slight decrease in CO2 permeance, but a significant reduction in the CO2/N2 selectivity from 78 to 27.1. Moreover, the mass transfer coefficient of gas molecules is expected to increase at a higher velocity, which leads to the increase of CO2 permeance at higher feed flow rates. It was concluded that the CO2 separation performance of the prepared membranes was significantly dependent on the membrane operating parameters, and process design and optimization are crucial to bringing CO2-separation membranes for industrial applications in post-combustion carbon capture.

Development of a scalable suspension culture for cardiac differentiation from human pluripotent stem cells.

To meet the need of a large quantity of hPSC-derived cardiomyocytes (CM) for pre-clinical and clinical studies, a robust and scalable differentiation system for CM production is essential. With a human pluripotent stem cells (hPSC) aggregate suspension culture system we established previously, we developed a matrix-free, scalable, and GMP-compliant process for directing hPSC differentiation to CM in suspension culture by modulating Wnt pathways with small molecules. By optimizing critical process parameters including: cell aggregate size, small molecule concentrations, induction timing, and agitation rate, we were able to consistently differentiate hPSCs to >90% CM purity with an average yield of 1.5 to 2×10(9) CM/L at scales up to 1L spinner flasks. CM generated from the suspension culture displayed typical genetic, morphological, and electrophysiological cardiac cell characteristics. This suspension culture system allows seamless transition from hPSC expansion to CM differentiation in a continuous suspension culture. It not only provides a cost and labor effective scalable process for large scale CM production, but also provides a bioreactor prototype for automation of cell manufacturing, which will accelerate the advance of hPSC research towards therapeutic applications.

[Japanese encephalitis virus with genotype I is predominant in Sichuan Province].

OBJECTIVE: To understand molecular characteristics of Japanese encephalitis virus (JEV) isolated from the major Japanese encephalitis epidemic areas in Sichuan Province, and to provide the foundation for JEV prevention. METHODS: 13 JEV strains were isolated from mosquitoes in Sichuan during 2007-2010, E genes and preM genes were sequenced and phylogenetic analyses were performed using MEGA5 molecular software. RESULTS: Phylogenetic analysis indicated that all 13 JEV strains from Sichuan belonged to genotype I, homologies at nucleotide level and deduced amino acid level in PreM gene were 97%-100% and 98.7%-100%, and 97.8%-99.9% and 99.6%-100% in E gene, respectively. Homologies at nucleotide level and deduced amino acid level in PreM gene between 13 JEV strains and JEV isolated in 2004 in Sichuan were 96.2%-99.1% and 97.5%-98.7%, and were 97.7%-99.6% and 98. 6%-100% in E gene, respectively. By comparison with vaacine strains P3 and SA14-14-2, homologies at nucleotide level and deduced amino acid level were 84.1%-85.8% and 93.7%-96.2% in PreM gene, and were 87.6%-88.3% and 97%-97.8% in E gene, respectively. The neurovirulence-related 8 amino acid sites encode by E gene remained unchanged in 13 JEV strains. CONCLUSION: JEV with genotype I predominated in Sichuan, nucleotide sequences and deduced amino acid sequences in PreM gene and E gene were highly conserved, key neurovirulence-rerlated sites remained unchanged. It suggested currently used vaccine is still capable of preventing JEV infection.

Effects of palifermin on antitumor activity of chemotherapeutic and biological agents in human head and neck and colorectal carcinoma xenograft models.

Damage to the gastrointestinal mucosa is a common dose-limiting toxicity of several anticancer therapies. Until recently, adequate control of oral mucositis was considered a significant unmet medical need, with most available treatments providing only palliative benefits without protecting the gastrointestinal epithelium from the damaging effects of cancer therapy. In 2005, palifermin [recombinant human keratinocyte growth factor (KGF)] was approved to decrease the incidence and duration of severe oral mucositis in patients with hematologic malignancies receiving myelotoxic therapy requiring hematopoietic stem cell support. Current trials are investigating the use of palifermin in solid tumor settings. The objective of this study was to determine whether combining palifermin with different chemotherapeutic or biological agents affected the antitumor activity of these agents in human head and neck (FaDu) and colorectal (HT29) carcinoma xenograft models. Nude CD1 mice were injected with 1 x 10(7) of either FaDu or HT29 cells, which express both KGF and epithelial growth factor receptors. Animals were treated with palifermin in various combinations with chemotherapeutic (5-fluorouracil and cisplatin) and/or biological (bevacizumab, cetuximab, and panitumumab) agents. Palifermin alone had no effect on either FaDu or HT29 tumor growth. Palifermin did not affect the therapeutic efficacy of 5-fluorouracil, cisplatin, cetuximab, bevacizumab, or panitumumab in any of the two- or three-way drug combinations tested in either model. The results of this study showed that palifermin did not promote the growth of two carcinoma cell lines that express functional KGF receptors and did not protect these tumor cells from the antitumor effects of several chemotherapeutic and biological agents.

Evaluation of a series of naphthamides as potent, orally active vascular endothelial growth factor receptor-2 tyrosine kinase inhibitors.

We have previously shown N-arylnaphthamides can be potent inhibitors of vascular endothelial growth factor receptors (VEGFRs). N-Alkyl and N-unsubstituted naphthamides were prepared and found to yield nanomolar inhibitors of VEGFR-2 (KDR) with an improved selectivity profile against a panel of tyrosine and serine/threonine kinases. The inhibitory activity of this series was retained at the cellular level. Naphthamides 3, 20, and 22 exhibited good pharmacokinetics following oral dosing and showed potent inhibition of VEGF-induced angiogenesis in the rat corneal model. Once-daily oral administration of 22 for 14 days led to 85% inhibition of established HT29 colon cancer and Calu-6 lung cancer xenografts at doses of 10 and 20 mg/kg, respectively.

Naphthamides as novel and potent vascular endothelial growth factor receptor tyrosine kinase inhibitors: design, synthesis, and evaluation.

A series of naphthyl-based compounds were synthesized as potential inhibitors of vascular endothelial growth factor (VEGF) receptors. Investigations of structure-activity relationships led to the identification of a series of naphthamides that are potent inhibitors of the VEGF receptor tyrosine kinase family. Numerous analogues demonstrated low nanomolar inhibition of VEGF-dependent human umbilical vein endothelial cell (HUVEC) proliferation, and of these several compounds possessed favorable pharmacokinetic (PK) profiles. In particular, compound 48 demonstrated significant antitumor efficacy against established HT29 human colon adenocarcinoma xenografts implanted in athymic mice. A full account of the preparation, structure-activity relationships, pharmacokinetic properties, and pharmacology of analogues within this series is presented.

Discovery of N-phenyl nicotinamides as potent inhibitors of Kdr.

Inhibition of tumor-induced angiogenesis is a promising strategy in anticancer research. Neovascularization is a process required for both tumor growth and metastasis. Enhanced understanding of the underlying molecular mechanisms has led to the discovery of a variety of pharmaceutically attractive targets. Decades of investigation suggest that vascular endothelial growth factor (VEGF) and its receptors, in particular VEGFR2 or kinase insert-domain-containing receptor (Kdr), play a critical role in the growth and survival of endothelial cells in newly forming vasculature. The clinical utility of inhibitors of this receptor tyrosine kinase is currently under intense investigation. Herein we report our efforts in this arena.

AMG 706, an oral, multikinase inhibitor that selectively targets vascular endothelial growth factor, platelet-derived growth factor, and kit receptors, potently inhibits angiogenesis and induces regression in tumor xenografts.

The growth of solid tumors is dependent on the continued stimulation of endothelial cell proliferation and migration resulting in angiogenesis. The angiogenic process is controlled by a variety of factors of which the vascular endothelial growth factor (VEGF) pathway and its receptors play a pivotal role. Small-molecule inhibitors of VEGF receptors (VEGFR) have been shown to inhibit angiogenesis and tumor growth in preclinical models and in clinical trials. A novel nicotinamide, AMG 706, was identified as a potent, orally bioavailable inhibitor of the VEGFR1/Flt1, VEGFR2/kinase domain receptor/Flk-1, VEGFR3/Flt4, platelet-derived growth factor receptor, and Kit receptors in preclinical models. AMG 706 inhibited human endothelial cell proliferation induced by VEGF, but not by basic fibroblast growth factor in vitro, as well as vascular permeability induced by VEGF in mice. Oral administration of AMG 706 potently inhibited VEGF-induced angiogenesis in the rat corneal model and induced regression of established A431 xenografts. AMG 706 was well tolerated and had no significant effects on body weight or on the general health of the animals. Histologic analysis of tumor xenografts from AMG 706-treated animals revealed an increase in endothelial apoptosis and a reduction in blood vessel area that preceded an increase in tumor cell apoptosis. In summary, AMG 706 is an orally bioavailable, well-tolerated multikinase inhibitor that is presently under clinical investigation for the treatment of human malignancies.

Regression of prostate cancer xenografts by a lentiviral vector specifically expressing diphtheria toxin A.

We have constructed a prostate-specific lentiviral vector based on the promoter of the prostate-specific antigen (PSA). The PSA promoter-based lentiviral vector has been used to deliver the diphtheria toxin A (DTA) gene into prostate cancer cells, and has shown promising tissue-specific eradication of prostate cancer cells in cell culture. To evaluate the efficacy of eradicating human prostate cancer cells in vivo, we used human LNCaP prostate xenografts in nude mice as an animal model and found that with a single injection of the DTA lentiviral vector into LNCaP prostate tumors, approximately 75% of the tumors (from three experiments; conducted 9/11, 11/15 and 3/4) in the animals were completely eradicated. The DTA vector has also shown the ability to cause tumor regression in recurrent prostate tumors. Intravenous injection of the DTA lentiviral vector into nude mice elicited no pathogenic effects, suggesting that this prostate tissue-specific vector is safe for eradicating prostate cancer cells in vivo.