226 resultados para Tityustoxin-k-alpha


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Ozone is a major air pollutant with adverse health effects which exhibit marked inter-individual variability. In mice, regions of genetic linkage with ozone-induced lung injury include the tumor necrosis factor-alpha (TNF), lymphotoxin-alpha (LTA), Toll-like receptor 4 (TLR4), superoxide dismutase (SOD2), and glutathione peroxidase (GPX1) genes. We genotyped polymorphisms in these genes in 51 individuals who had undergone ozone challenge. Mean change in FEV1 with ozone challenge, as a percentage of baseline, was -3% in TNF -308G/A or A/A individuals, compared with -9% in G/G individuals (p = 0.024). When considering TNF haplotypes, the smallest change in FEV1 with ozone exposure was associated with the TNF haplotype comprising LTA +252G/TNF -1031T/TNF -308A/TNF -238G. This association remained statistically significant after correction for age, sex, disease, and ozone concentration (p = 0.047). SOD2 or GPX1 genotypes were not associated with lung function, and the TLR4 polymorphism was too infrequent to analyze. The results of this study support TNF as a genetic factor for susceptibility to ozone-induced changes in lung function in humans, and has potential implications for stratifying health risks of air pollution.

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The aims of this study were to examine the plasma concentrations of inflammatory mediators including cytokines induced by a single bout of eccentric exercise and again 4 weeks later by a second bout of eccentric exercise of the same muscle group. Ten untrained male subjects performed two bouts of the eccentric exercise involving the elbow flexors (6 sets of 5 repetitions) separated by four weeks. Changes in muscle soreness, swelling, and function following exercise were compared between the bouts. Blood was sampled before, immediately after, 1 h, 3 h, 6 h, 24 h (1 d), 48 h (2 d), 72 h (3 d), 96 h (4 d) following exercise bout to measure plasma creatine kinase (CK) activity, plasma concentrations of myoglobin (Mb), interleukin (IL)-1 beta, IL-1 receptor antagonist (IL-1ra), IL-4, IL-6, IL-8, IL-10, IL-12p40, tumor necrosis factor (TNF)-alpha, granulocyte colony-stimulating factor (G-CSF), myeloperoxidase (MPO), prostaglandin E-2 (PGE(2)), heat shock protein (HSP) 60 and 70. After the first bout, muscle soreness increased significantly, and there was also significant increase in upper arm circumference; muscle function decreased and plasma CK activity and Mb concentration increased significantly. These changes were significantly smaller after the second bout compared to the first bout, indicating muscle adaptation to the repeated bouts of the eccentric exercise. Despite the evidence of greater muscle damage after the first bout, the changes in cytokines and other inflammatory mediators were quite minor, and considerably smaller than that following endurance exercise. These results suggest that eccentric exercise-induced muscle damage is not associated with the significant release of cytokines into the systemic circulation. After the first bout, plasma G-CSF concentration showed a small but significant increase, whereas TNF-alpha and IL-8 showed significant decreases compared to the pre-exercise values. After the second bout, there was a significant increase in IL-10, and a significant decrease in IL-8. In conclusion, although there was evidence of severe muscle damage after the eccentric exercise, this muscle damage was not accompanied by any large changes in plasma cytokine concentrations. The minor changes in systemic cytokine concentration found in this study might reflect more rapid clearance from the circulation, or a lack of any significant metabolic or oxidative demands during this particular mode of exercise. In relation to the adaptation to the muscle damage, the anti-inflammatory cytokine IL-10 might work as one of the underlying mechanisms of action.

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The chi-conopeptides MrIA and MrIB are 13-residue peptides with two disulfide bonds that inhibit human and rat norepinephrine transporter systems and are of significant interest for the design of novel drugs involved in pain treatment. In the current study we have determined the solution structure of MrIA using NMR spectroscopy. The major element of secondary structure is a hairpin with the two strands connected by an inverse gamma-turn. The residues primarily involved in activity have previously been shown to be located in the turn region (Sharpe, I. A.; Palant, E.: Schroder, C. L; Kaye, D. M.; Adams, D. I.; Alewood, P. F.; Lewis, R. J. J Biol Client 2003, 278, 40317-40323), which appears to be more flexible than the beta-strands based on disorder in the ensemble of calculated structures. Analogues of MrIA with N-terminal truncations indicate that the N-terminal residues play a role in defining a stable conformation and the native disulfide connectivity. In particular, noncovalent interactions between Val3 and Hypl2 are likely to be involved in maintaining a stable conformation. The N-terminus also affects activity, as a single N-terminal deletion introduced additional pharmacology at rat vas deferens, while deleting the first two amino acids reduced chi-conopeptide potency. This article was originally published online as an accepted preprint. The Published Online date corresponds to the preprint version. You can request a copy of the preprint by entailing the Biopolymers editorial office at biopolymers@wiley.com (c) 2005 Wiley Periodicals, Inc.

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Polysaccharides from the red alga Phacelocarpos peperocarpos were extracted with hot water, clarified, and precipitated with 2-propanol. The native preparation was highly sulfated (36.2% w/w). Alkali modification decreased the sulfate content by 2.0% w/w. The alkali-modified polysaccharide is composed mostly of galactose (Gal, 51 mol%) and 3,6-anhydrogalactose (AnGal, 41 mol%), with minor amounts of a mono-O-methylgalactose (MeGal, 1 mol%), xylose (Xyl, 6 mol%), and glucose (Glc, 1 mol%). The FTIR spectrum of the alkali-modified polysaccharide resembled K-carrageenan with absorption at 930 cm(-1) (indicative of AnGal) and 850 cm(-1) (Gal ii-sulfate). However, an additional, major band of absorption occurred at 820 cm(-1) indicating the presence of equatorial sulfate ester substitution at O-6 of Gal residues, A combination of linkage and C-13 NMR spectroscopic analyses showed that the polysaccharide was composed predominantly of a novel repeating-unit, O-beta-D-galactopyranosyl 4,6-disulfate)-(1 --> 4)-3,6-anhydro-alpha-D-galactopyranose. Minor structural variations also occurred, including alternative patterns of sulfation and the presence of terminal Xylp, The location of the terminal Xylp residues was not certain but evidence supported their attachment at O-3 of some 4-linked Galp residues. The cell-wall galactans remain unchanged during the life cycle of the alga. (C) 1996 Elsevier Science Ltd.

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Human follicle stimulating hormone is a pituitary glycoprotein that is essential for the maintenance of ovarian follicle development and testicular spermatogenesis. Like other members of the glycoprotein hormone family, it contains a common a subunit and a hormone specific beta subunit. Each subunit contains two glycosylation sites. The specific structures of the oligosaccharides of human follicle stimulating hormone have been shown to influence both the in vitro and in vivo bioactivity. Since the carbohydrate structure of a protein reflects the glycosylation apparatus of the host cells in which the protein is expressed, we examined the isoform profiles, in vitro bioactivity and metabolic clearance of a preparation of purified recombinant human follicle stimulating hormone derived from a stable, transfected Sp2/0 myeloma cell line, and pituitary human follicle stimulating hormone. Isoelectric focussing and chromatofocussing studies of human follicle stimulating hormone preparations both showed a more basic isoform profile for the recombinant human follicle stimulating hormone compared to that of pituitary human follicle stimulating hormone. The recombinant human follicle stimulating hormone had a significantly higher radioreceptor activity compared to that of pituitary human follicle stimulating hormone, consistent with a greater in vitro potency. Pharmacokinetic studies in rats indicated a similar terminal half life (124 min) to that of the pituitary human follicle stimulating hormone (119 min). Preliminary carbohydrate analysis showed recombinant human follicle stimulating hormone to contain high mannose and/or hybrid type, in addition to complex type carbohydrate chains, terminating with both alpha 2,3 and alpha 2,6 linked sialic acids. These results demonstrate that recombinant human follicle stimulating hormone made in the Sp2/0 myeloma cells is sialylated, has a more basic isoform profile, and has a greater in vitro biological potency compared to those of the pituitary human follicle stimulating hormone.

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The current study aims to ascertain the fate of the melanocyte stimulating hormone (MSH) receptor and its ligand [Nle(4), D-Phe(7)]alpha-MsH (NDP-MSH) following binding to murine B16 melanoma cells. Cells were incubated with [I-125]-NDP-MSH for up to 180 min and binding, internalization and degradation determined. Intracellular trafficking of the radiolabel was assessed !using Percoll density gradient centrifugation of homogenized cells. Receptor down-regulation and receptor mRNA levels were also measured over 96 hr after exposure to 1 mu M ligand. NDP-MSH accumulation increased with time in a temperature-dependent manner and was inhibited by excess peptide. The ligand was rapidly internalized and translocated to the lysosomal compartment where it was degraded. Internalization was accompanied by a loss or down-regulation of cell surface receptors, suggesting internalization of the NDP-MSH-receptor complex. No recycling of the receptors between the plasma membrane and intracellular compartments could be detected in this cell-hue. Approximately 15% of the surface receptors were resistant to down-regulation, possibly indicating receptor heterogeneity. Down-regulation persisted ibr up to 96 hr and was accompanied by a decrease in MSH receptor mRNA levels 48 hr after treatment. However, before this time, transcript levels were the same in treated and control cells. In contrast to what was seen with NDP-MSH, cell surface receptors removed with trypsin wc:re rapidly replaced. These results show that NDP-MSH not only induced MSH receptor :internalization but also inhibited receptor turnover, resulting in a prolonged down-regulation. It is concluded that, in B16 cells, the MSH receptor undergoes ligand-dependent internalization, resulting in a prolonged down-regulation. Copyright (C) 1996 Elsevier Science Ltd

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Determination of the 16S rRNA gene sequence of Caulobacter subvibrioides ATCC 15264(T) (T = type strain) confirmed that this species is a member of the alpha subclass of the Proteobacteria and showed that it is phylogenetically most closely related to the Caulobacter group comprising the species Caulobacter bacteroides, Caulobacter crescentus, and Brevandimonas (Pseudomonas) diminuta, for which 16S rRNA sequences of the type strains are currently available. The closest known relative of strain ATCC 15264(T) among these species is B. diminuta (level of direct pairwise sequence similarity, 95%). On the basis of its previously determined 16S rRNA sequence (accession number M83797), C. subvibrioides is most closely related to Sphingomonas adhaesiva in the alpha-4 subgroup (level of similarity, 97.7%). Analysis of the hydroxy fatty acids of C. subvibrioides ATCC 15264(T) showed that the 2-hydroxymyristic acid which is characteristic of the genus Sphingomonas was absent.

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Papillomaviruses (PVs) bind in a specific and saturable fashion to a range of epithelial and other cell lines. Treatment of cells with trypsin markedly reduces their ability to bind virus particles, suggesting that binding is mediated via a cell membrane protein. We have investigated the interaction bf human PV type 6b L1 virus-like particles (VLPs) with two epithelial cell lines, CV-1 and HaCaT, which bind VLPs, and a B-cell line (DG75) previously shown not to bind VLPs. Immunoprecipitation of a mixture of PV VLPs with [S-35]methionine-labeled cell extracts and with biotin-labeled cell surface proteins identified four proteins from CV-1 and HaCaT cells of 220, 120, 87, and 35 kDa that reacted with VLPs and were not present in DG75 cells. The alpha(6) beta(4) integrin complex has subunits corresponding to the VLP precipitated proteins, and the tissue distribution of this complex suggested that it was a candidate human PV receptor. Monoclonal antibodies (MAbs) to the alpha(6) or beta(4) integrin subunits precipitated VLPs from a mixture of CV-1 cell proteins and VLPs, whereas MAbs to other integrin subunits did not. An alpha(6) integrin-specific MAb (GoH3) inhibited VLP binding to CV-1 and HaCaT cells, whereas an anti-beta(4) integrin MAb and a range of integrin-specific and other MAbs did not. Furthermore, human laminin, the natural ligand for the alpha(6) beta(4) integrin, was able to block VLP binding. By use of sections of monkey esophagus, the distribution of alpha(6), integrin expression in the basal epithelium was shown to coincide with the distribution of bound VLPs. Taken together, these data suggest that VLPs bind specifically to the alpha(6) integrin subunit and that integrin complexes containing alpha(6) integrin complexed with either beta(1) or beta(4) integrins may act as a receptor for PV binding and entry into epithelial cells.

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Necessary conditions on n, m and d are given for the existence of an edge-disjoint decomposition of K-n\K-m into copies of the graph of a d-dimensional cube. Sufficiency is shown when d = 3 and, in some cases, when d = 2(t). We settle the problem of embedding 3-cube decompositions of K-m into 3-cube decompositions of K-n; where n greater than or equal to m.

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The effects of 4 estrus synchronization treatments on intervals to and synchrony of estrus and ovulation, on timing of the preovulatory LH surge and associated changes in plasma progesterone, LH, FSH, and 17 beta-estradiol (E(2)) were investigated in 48 Bos indicus cows. Treatment 1 consisted of 2 injections of PGF(2 alpha) 14 d apart (n = 12); Treatment 2 of a subcutaneous 3-mg norgestomet implant and an intramuscular injection of 3 mg of norgestomet and 5 mg estradiol valerate, with the implant removed 10 d later (n = 12; norgestomet-estradiol); Treatment 3 of norgestomet-estradiol, with a subcutaneous injection of PMSG given at time of implant removal (Day 10; n = 12); and Treatment 4 of norgestomet implant (as for Treatments 2 and 3) inserted for 10 d, with an intramuscular injection of PGF(2 alpha) given at the time of implant removal (n = 12). The experiment was conducted in 2 replicates (24 cows/replicate, 6 cows/group). Estrus, ovulation and timing of the preovulatory surge of LH varied less in cows treated with norgestomet-estradiol and PMSG than in cows in Treatments 1 and 4 (P < 0.008). Treatment with PMSG;educed variation in ovulation times and timing of the LH surge in cows treated with norgestomet-estradiol (P < 0.02). Concentrations of E(2) were higher in cows in Treatments 2 and 3 on the final day of treatment and at about 6 h post ovulation compared with cows in Treatments 1 and 4 (P < 0.05). Different methods for synchronizing estrus did not alter sequential endocrine and behavioral changes in relation to the timing of the LH peak, and the results were consistent with current recommendations for insemination times in Bos taurus cattle. (C) 1997 by Elsevier Science Inc.

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alpha-Aspartyl-containing cyclic pentapeptides were synthesised in high yields using a strategy that maintained fluorenylmethyl protection on the aspartic acid side chain during chain assembly, resin cleavage and cyclisation of the linear precursors. Tetra-n-butylammonium fluoride treatment of the fluorenylmethyl-protected cyclic peptides catalysed imide formation, whereas piperidine-induced deprotection resulted in good yields of the target cyclic peptides.