941 resultados para bis-insertion
Resumo:
Reprogramming of somatic cells to pluripotency promises to boost cellular therapy. Most instances of direct reprogramming have been achieved by forced expression of defined exogenous factors using multiple viral vectors. The most used 4 transcription factors, octamer-binding transcription factor 4 (OCT4), (sex determining region Y)-box 2 (SOX2), Kruppel-like factor 4 (KLF4), and v-myc myelocytomatosis viral oncogene homolog (C-MYC), can induce pluripotency in mouse and human fibroblasts. Here, we report that forced expression of a new combination of transcription factors (T-cell leukemia/lymphoma protein 1A [TCL-1A], C-MYC, and SOX2) is sufficient to promote the reprogramming of human fibroblasts into pluripotent cells. These 3-factor pluripotent cells are similar to human embryonic stem cells in morphology, in the ability to differentiate into cells of the 3 embryonic layers, and at the level of global gene expression. Induced pluripotent human cells generated by a combination of other factors will be of great help for the understanding of reprogramming pathways. This, in turn, will allow us to better control cell-fate and apply this knowledge to cell therapy.
Resumo:
A series of photosensitizers (PS), which are meso-substituted tetra-cationic porphyrins, was synthesized in order to study the role of amphiphilicity and zinc insertion in photodynamic therapy (PDT) efficacy. Several properties of the PS were evaluated and compared within the series including photophysical properties (absorption spectra, fluorescence quantum yield Phi(f), and singlet oxygen quantum yield Phi(Delta)), uptake by vesicles, mitochondria and HeLa cells, dark and phototoxicity in HeLa cells. The photophysical properties of all compounds are quite similar (Phi(f) <= 0.02; Phi(Delta) similar to 0.8). An increase in lipophilicity and the presence of zinc in the porphyrin ring result in higher vesicle and cell uptake. Binding in mitochondria is dependent on the PS lipophilicity and on the electrochemical membrane potential, i.e., in uncoupled mitochondria PS binding decreases by up to 53%. The porphyrin substituted with octyl groups (TC8PyP) is the compound that is most enriched in mitochondria, and its zinc derivative (ZnTC8PyP) has the highest global uptake. The stronger membrane interaction of the zinc-substituted porphyrins is attributed to a complexing effect with phosphate groups of the phospholipids. Zinc insertion was also shown to decrease the interaction with isolated mitochondria and with the mitochondria of HeLa cells, an effect that has been explained by the particular characteristics of the mitochondrial internal membrane. Phototoxicity was shown to increase proportionally with membrane binding efficiency, which is attributed to favorable membrane interactions which allow more efficient membrane photooxidation. For this series of compounds, photodynamic efficiency is directly proportional to the membrane binding and cell uptake, but it is not totally related to mitochondrial targeting.
Resumo:
About 95% of HTLV-1 infected patients remain asymptomatic throughout life, and the risk factors associated with the development of related diseases, such as HAM/TSP and ATL, are not fully understood. The human leukocyte antigen-G molecule (HLA-G), a nonclassical HLA class I molecule encoded by MHC, is expressed in several pathological conditions, including viral infection, and is related to immunosuppressive effects that allow the virus-infected cells to escape the antiviral defense of the host. The 14-bp insertion/deletion polymorphism of exon 8 HLA-G gene influences the stability of the transcripts and could be related to HTLV-1-infected cell protection and to the increase of proviral load. The present study analyzed by conventional PCR the 14-bp insertion/deletion polymorphism of exon 8 HLA-G gene in 150 unrelated healthy subjects, 82 HTLV-1 infected patients with symptoms (33 ATL and 49 HAM), and 56 asymptomatic HTLV-1 infected patients (HAC). In addition, the proviral load was determined by quantitative real-time PCR in all infected groups and correlated with 14-bp insertion/deletion genotypes. The heterozygote genotype frequencies were significantly higher in HAM, in the symptomatic group, and in infected patients compared to control (p < 0.05). The proviral load was higher in the symptomatic group than the HAC group (p < 0.0005). The comparison of proviral load and genotypes showed that -14-bp/-14-bp genotype had a higher proviral load than +14-bp/-14-bp and +14-bp/+14-bp genotypes. Although HLA-G 14-bp polymorphism does not appear to be associated
Resumo:
In the title compound, [Ni(C(20)H(17)N(2)O(2)S)(2)], the NiII atom is coordinated by the S and O atoms of two 1,1-dibenzyl-3-[(furan-2-yl)carbonyl]thioureate ligands in a distorted square-planar geometry. The two O and two S atoms are mutually cis to each other. The Ni-S and Ni-O bond lengths lie within the range of those found in related structures. The dihedral angle between the planes of the two chelating rings is 20.33 (6)degrees.
Resumo:
In the title complex, (C(24)H(20)P)(2)[Sn(C(2)H(3)NO(2)S(3))(3)], the Sn(IV) atom is coordinated by three N-(methylsulfonyl) dithiocarbimate bidentate ligands through the anionic S atoms in a slightly distorted octahedral coordination geometry. There is one half-molecule in the asymmetric unit; the complex is located on a crystallographic twofold rotation axis passing through the cation and bisecting one of the (non-symmetric) ligands, which appears thus disordered over two sites of equal occupancy. In the crystal structure, weak intermolecular C-H center dot center dot center dot O and C-H center dot center dot center dot S interactions contribute to the packing stabilization.
Resumo:
In the title compound, [Cu(C(20)H(17)N(2)O(2)S)(2)], the Cu(II) atom is coordinated by the S and O atoms of two 1,1-dibenzyl-3-(furan-2-ylcarbonyl)thioureate ligands in a distorted square-planar geometry. The two O and two S atoms are mutually cis to each other. The Cu-S and Cu-O bond lengths lie within the ranges of those found in related structures. The dihedral angle between the planes of the two chelating rings is 26.15 (6)degrees.
Resumo:
In the title compound, [Ni(C(18)H(13)N(2)O(2)S)(2)], the Ni(II) atom is coordinated by the S and O atoms of two N-furoyl-N ',N '-diphenylthioureate ligands in a slightly distorted squareplanar coordination geometry. The two O and two S atoms are cis to each other.
Resumo:
In the title compound, [Ni(C22H19N2OS)(2)], the Ni-II atom is coordinated by the S and O atoms of two N-benzoyl-N',N'-dibenzylthioureate ligands in a slightly distorted square-planar geometry. The two O atoms are cis, as are the two S atoms.
Resumo:
The piperidone ring in the title compound, C(18)H(17)Cl(2)NOS(2), has a distorted half-chair conformation. The S-bound benzene rings are approximately perpendicular to and splayed out of the mean plane through the piperidone ring [dihedral angles = 71.86 (13) and 46.94 (11)degrees]. In the crystal, C-H center dot center dot center dot O interactions link the molecules into [010] supramolecular chains with a helical topology. C-H center dot center dot center dot Cl and C-H center dot center dot center dot pi interactions are also present.
Resumo:
The structure analysis of the title compound, C(14)H(16)O(2)S(2), shows the SMe and H atoms of the bond linking the six-membered rings to be syn and also to be syn to the bridgehead -CH(2)- group. Each of the five-membered rings adopts an envelope conformation at the bridgehead -CH(2)- group. The dione-substituted ring adopts a folded conformation about the 1,4-C center dot center dot center dot C vector, with the ketone groups lying to one side. The cyclohexene ring adopts a boat conformation.
Resumo:
Angiotensin I-converting enzyme (ACE) is recognized as one of the main effector molecules involved in blood pressure regulation. In the last few years some polymorphisms of ACE such as the insertion/deletion (I/D) polymorphism have been described, but their physiologic relevance is poorly understood. In addition, few studies investigated if the specific activity of ACE domain is related to the I/D polymorphism and if it can affect other systems. The aim of this study was to establish a biochemical and functional characterization of the I/D polymorphism and correlate this with the corresponding ACE activity. For this purpose, 119 male brazilian army recruits were genotyped and their ACE plasma activities evaluated from the C- and N-terminal catalytic domains using fluorescence resonance energy transfer (FRET) peptides, specific for the C-domain (Abz-LFK(Dnp)OH), N-domain (Abz-SDK(Dnp)P-OH) and both C- and N-domains (Abz-FRK(Dnp)P-OH). Plasma kallikrein activity was measured using Z-Phe-Arg-AMC as substrate and inhibited by selective plasma kallikrein inhibitor (PKSI). Some physiological parameters previously described related to the I/D polymorphism such as handgrip strength, blood pressure, heart rate and BMI were also evaluated. The genotype distribution was II n = 27, ID n = 64 and DD n = 28. Total plasma ACE activity of both domains in II individuals was significantly lower in comparison to ID and DD. This pattern was also observed for C- and N-domain activities. Difference between ID and DD subjects was observed only with the N-domain specific substrate. Blood pressure, heart rate, handgrip strength and BMI were similar among the genotypes. This polymorphism also affected the plasma kallikrein activity and DD group presents high activity level. Thus, our data demonstrate that the I/D ACE polymorphism affects differently both ACE domains without effects on handgrip strength. Moreover, this polymorphism influences the kallikrein-kinin system of normotensive individuals. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
In the last few years great efforts have been made in order to find and to develop environmentally friendly substitutes for Cr6+ pre-treatments applied on aluminium alloys used in the aircraft industry. Among the potential substitutes, silane layers have attracted considerable interest from researchers and from the industry. The present work investigates the anti-corrosion behaviour of (bis-1, 2-(triethoxysilyl) ethane (BTSE)) silane layers modified with Ce ions and/or silica nanoparticles applied on Al alloy 2024-T3 substrates. The corrosion behaviour was investigated in 0.1 M NaCl solution via d.c. polarization and electrochemical impedance spectroscopy (EIS). Contact angle measurements and XPS were used to assess information on the chemistry of the silane pre-treated surfaces. The results have shown that the introduction of additives improves the corrosion protection properties of the silane layer. (c) 2008 Elsevier Ltd. All rights reserved.
Resumo:
This paper describes a new method for the preparation of 1,5-bis(4-hydroxy-3-methoxyphenyl)-1,4-pentadien-3-one 1 and its derivatives 2-5. This set of synthetic compounds exhibited high antitumoral activities regarding in vitro screening against several human tumor cell lines as lung carcinoma NCI-460, melanoma UACC-62, breast MCF-7, colon HT-29, renal 786-O, ovarian OVCAR-03 and ovarian expressing the resistance phenotype for adriamycin NCI-ADR/ RES, prostate PC-3, and leukemia K-562. Compounds were also tested against murine tumor cell line B16F10 melanoma and lymphocytic leukemia L1210 as well as to their effect toward normal macrophages. Specific activity against colon cancer cells HT-29 was observed for all tested compounds and suggests further studies with models of colon cancer. Compounds 1, 2, and 4 showed significant cytotoxic activity with IC(50) values <= 2.3 mu M for all human cancer cell lines. Intraperitoneal acute administration of compound 1 and 2 showed very low toxicity rate. (C) 2010 Elsevier Ltd. All rights reserved.
Resumo:
C14H12F2Te2, monoclinic, C12/c1 (no. 15), a = 23.650(2) angstrom, b = 7.792(1) angstrom, c = 7.556(1) angstrom, beta = 106.47(1)degrees, V = 1335.2 angstrom(3), Z = 4, R-gt(F) = 0.041, wR(ref)(F-2) = 0.123, T= 98 K.