790 resultados para Aggregation agent


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Objectives. To compare the efficacy of three different standard chemotherapy regimens for low-risk gestational trophoblastic disease according to the FIGO staging system in a single-institute setting. Methods. From 1980 until 2002, we retrospectively reviewed 108 cases with low-risk persistent gestational trophoblastic disease who were treated with first-line chemotherapy. Patients were divided in three groups according to chemotherapy regimen: patients treated with methotrexate (MTX group; n=42), patients treated with dactinomycin (ACT group; n=42) and patients treated with methotrexate and dactinomycin in combination (MACT group; n=24). We compared the number of chemotherapy courses for achieving remission, the duration of treatment, the adverse side effects, the efficacy of the treatment and the need for performing a hysterectomy among the groups Results. The complete remission rates were 69%, 61.4% and 79.1% for methotrexate (MTX), dactinomycin (ACT) and the combination regimen (MACT) treated groups, respectively (p=0.7). The duration of the treatment and the number of chemotherapy courses were similar among the groups (p = 0.2 and p = 0.4, respectively). Adverse side effects rate was reported to be 62.5% in the MACT group, 28.6% in the MTX group and 19.1% in the ACT group (p=0.0003). Second-line chemotherapy was indicated for 30 patients. Hysterectomy was performed in 21 patients overall, and there was no difference among the groups (P=0.6). Conclusion. Our analysis indicates that single-agent chemotherapy regimens are as effective as combination chemotherapy for low-risk gestational trophoblastic disease. Dactinomycin is a less toxic drug and might offer the best cost-effective treatment option. Methotrexate must be considered as the regimen of choice for low resource areas because of the feasibility of its administration. (c) 2007 Elsevier Inc. All rights reserved.

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Platelet aggregation and acute inflammation are key processes in vertebrate defense to a skin injury. Recent studies uncovered the mediation of 2 serine proteases, cathepsin G and chymase, in both mechanisms. Working with a mouse model of acute inflammation, we revealed that an exogenous salivary protein of Ixodes ricinus, the vector of Lyme disease pathogens in Europe, extensively inhibits edema formation and influx of neutrophils in the inflamed tissue. We named this tick salivary gland secreted effector as I ricinus serpin-2 (IRS-2), and we show that it primarily inhibits cathepsin G and chymase, while in higher molar excess, it affects thrombin activity as well. The inhibitory specificity was explained using the crystal structure, determined at a resolution of 1.8 angstrom. Moreover, we disclosed the ability of IRS-2 to inhibit cathepsin G-induced and thrombin-induced platelet aggregation. For the first time, an ectoparasite protein is shown to exhibit such pharmacological effects and target specificity. The stringent specificity and biological activities of IRS-2 combined with the knowledge of its structure can be the basis for the development of future pharmaceutical applications. (Blood. 2011;117(2):736-744)

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Objectives. To evaluate the influence of different tertiary amines on degree of conversion (DC), shrinkage-strain, shrinkage-strain rate, Knoop microhardness, and color and transmittance stabilities of experimental resins containing BisGMA/TEGDMA (3: 1 wt), 0.25wt% camphorquinone, 1wt% amine (DMAEMA, CEMA, DMPT, DEPT or DABE). Different light-curing protocols were also evaluated. Methods. DC was evaluated with FTIR-ATR and shrinkage-strain with the bonded-disk method. Shrinkage-strain-rate data were obtained from numerical differentiation of shrinkage-strain data with respect to time. Color stability and transmittance were evaluated after different periods of artificial aging, according to ISO 7491: 2000. Results were evaluated with ANOVA, Tukey, and Dunnett`s T3 tests (alpha = 0.05). Results. Studied properties were influenced by amines. DC and shrinkage-strain were maximum at the sequence: CQ < DEPT < DMPT <= CEMA approximate to DABE < DMAEMA. Both DC and shrinkage were also influenced by the curing protocol, with positive correlations between DC and shrinkage-strain and DC and shrinkage-strain rate. Materials generally decreased in L* and increased in b*. The strong exception was the resin containing DMAEMA that did not show dark and yellow shifts. Color varied in the sequence: DMAEMA < DEPT < DMPT < CEMA < DABE. Transmittance varied in the sequence: DEPT approximate to DABE < DABE approximate to DMPT approximate to CEMA < DMPT approximate to CEMA approximate to DMAEMA, being more evident at the wavelength of 400 nm. No correlations between DC and optical properties were observed. Significance. The resin containing DMAEMA showed higher DC, shrinkage-strain, shrinkage-strain rate, and microhardness, in addition to better optical properties. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

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This study investigated whether sodium bicarbonate solution, applied on enamel previously exposed to a simulated intrinsic acid, can control dental erosion. Volunteers wore palatal devices containing enamel slabs, which were exposed twice daily extra-orally to hydrochloric acid (0.01 M, pH 2) for 2 min. Immediately afterwards, the palatal devices were re-inserted in the mouth and volunteers rinsed their oral cavity with a sodium bicarbonate solution or deionized water for 60 s. After the washout period, the palatal devices were refilled with a new set of specimens and participants were crossed over to receive the alternate rinse solution. The surface loss and surface microhardness (SMH) of specimens were assessed. The surface loss of eroded enamel rinsed with a sodium bicarbonate solution was significantly lower than the surface loss of eroded enamel rinsed with deionized water. There were no differences between treatments with sodium bicarbonate and deionized water for SMH measurements. Regardless of the solution used as an oral rinse, eroded enamel showed lower SMH than uneroded specimens. Rinsing with a sodium bicarbonate solution after simulated endogenous erosive challenge controlled enamel surface loss but did not alter the microhardness.

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Purpose: To evaluate the effect of a 10% carbamide peroxide-containing bleaching agent on brushing abrasion of esthetic restorative materials. Methods: Using a randomized complete block design, 150 specimens (n = 15) measuring 3 x 3 x 2 mm were fabricated into acrylic resin cylinders, using one of the restorative materials: a microfilled resin composite (At), a hybrid resin composite (Ch), a flowable resin composite (Wa), a resin-modified glass-ionomer cement (Fj) and a polyacid-modified resin composite (Dy). The bleaching agent or artificial saliva (control) was applied for 2 hours/day. After that, 120 brushing strokes were simulated automatically and the samples were kept in artificial saliva. Such bleaching/brushing cycle was performed daily for 21 days. Wear depth was assessed using profilometry. Results: Bleaching did not show significant effect on wear depth. There was a significant difference among the restorative materials. Tukey`s test showed that (Al=Ch) < (Wa) < (Fj) and that Dy was only different from Fj. (Am J Dent 2009;22:171-174).

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Resources can be aggregated both within and between patches. In this article, we examine how aggregation at these different scales influences the behavior and performance of foragers. We developed an optimal foraging model of the foraging behavior of the parasitoid wasp Cotesia rubecula parasitizing the larvae of the cabbage butterfly Pieris rapae. The optimal behavior was found using stochastic dynamic programming. The most interesting and novel result is that the effect of resource aggregation within and between patches depends on the degree of aggregation both within and between patches as well as on the local host density in the occupied patch, but lifetime reproductive success depends only on aggregation within patches. Our findings have profound implications for the way in which we measure heterogeneity at different scales and model the response of organisms to spatial heterogeneity.

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Marked elevation of dioxin associated with the herbicide Agent Orange was recently found in 19 of 20 blood samples from persons living in Bien Hoa, a large city in southern Vietnam. This city is located near an air base that was used for Agent Orange spray missions between 1962 and 1970. A spill of Agent Orange occurred at this air base more than 30 years before blood samples were collected in 1999. Samples were collected, frozen, and sent to a World Health Organization-certified dioxin laboratory fm congener-specific analysis as part of a Vietnam Red Cross project. Previous analyses of more than 2200 pooled blood samples collected in the 1990s identified Bien Hoa as one of several southern Vietnam areas with persons having elevated blood dioxin levels from exposure to Agent Orange. In sharp contrast to this study, our previous research showed decreasing tissue dioxin levels over time since 1970. Only the dioxin that contaminated Agent Orange, 2,3, 7, 8-tetrachlmodibenzo-p-dioxin (TCDD), was elevated in the blood of 19 of 20 persons sampled from Bien Hoa. A comparison pooled sample from 100 residents of Hanoi, where Agent Orange was not used, measured blood TCDD levels of 2 parts per trillion (ppt). TCDD levels of up to 271 ppt, a 135-fold increase, were found in Bien Hoa residents. TCDD contamination was also found in some nearby soil and sediment samples. Persons new to this region and children born after Agent Orange spraying ended also had elevated TCDD levels. This TCDD uptake was recent and occurred decades after spraying ended. We hypothesize that a major route of current and past exposures is from the movement of dioxin from soil into river sediment, then into fish, and from fish consumption into people.

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Jembrana disease virus (JDV) is a newly isolated and characterised bovine lentivirus. It causes an acute disease in Ball cattle (Bos javanicus). which can be readily transmitted to susceptible cattle with 17% mortality. There is as yet no treatment or preventive vaccine. We have developed a gene transfer vector system based on JDV that has three components. The first of the components is a bicistronic transfer vector plasmid that was constructed to contain cis-sequences from the JDV genome, including 5 '- and 3 ' -long terminal repeats (LTRs), 0.4 kb of truncated gag and 1.1 kb of 3 ' -env, a multiple cloning site to accommodate the gene(s) of interest for transfer, and an internal ribosome entry site plus the neomycin phosphotransferase (Neo) gene cassette for antibiotic selection. The second element is a packaging plasmid that contains trans-sequences. including gag, pol. vif, tar and rev: but without the env and packaging signals. The third is a plasmid encoding the G glycoprotein of vesicular stomatitis virus (VSV-G) to supply the vector an envelope for pseudotyping. Cotransfection of 293T cells with these three plasmid components produced VSV-G pseudotyped. disabled, replication defective, bicistronic JDV vectors encoding the green fluorescent protein (EGFP) and the Neo resistance selection maker simultaneously with a titre range of (0.4-1.2) x 10(6) CFU/ml. Transduction of several replicating primary and transformed cells from cattle, primate and human sources and importantly growth-arrested cells with the JDV vectors showed high efficiency of EGFP gene transfer at 35-75%, which was stable and the expression of EGFP was long term. Furthermore, these JDV vectors were designed to suit the inclusion and expression of genes corresponding to JDV specific proteins, such as gag or env, for the development of vaccines for Jembrana disease. This strategy should also be applicable to other bovine diseases as wall. The design and construction of the JDV vector system should facilitate the study of the lentivirology and pathogenesis of the diseases associated with JDV or other bovine virus infections. To our knowledge, this is the first such vector system developed from a cattle virus. (C) 2001 Elsevier Science B.V. All rights reserved.

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Effects of gall damage by the introduced moth Epiblema stremiana on different growth stages of the weed Parathenium hysterophorus was evaluated in a field cage using potted plants with no competition and in naturally regenerated populations with intraspecific competition. Gall damage at early stages of plant growth reduced the plant height, main stem height, flower production, lear production, and shoot and root biomass. All galled, potted plants with no competition produced flowers irrespective of the growth stage at which the plants were affected by galling, but lesser than in ungalled plants. Gall induction during early growth stages in field plants experiencing competition prevented 30% of the plants reaching flowering. However, 6% of the field plants escaped from gall damage, as their main stems were less vigorous to sustain the development of galls. Flower production per unit total plant biomass was lower in galled plants than in ungalled plants, and the reduction was more intense when gall damage was initiated at early stages of plant growth. In potted plants with no competition, the number of galls increased with the plant vigour, as the gall insects preferred more vigorous plants. But in field plants there were no relationship between gall abundance and plant vigour, as intraspecific competition enhanced the negative effects of galling by reducing the vigour of the weed.

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High levels of mortality in the Mediterranean bath sponge industry have raised concerns for the future of sponge farms. Healthy sponges feed predominantly on bacteria, and many harbour a wide diversity of inter- and extra-cellular symbiotic bacteria. Here we describe the first isolation and description of a pathogenic bacterium from an infected marine sponge. Microbiological examination of tissue necrosis in the Great Barrier Reef sponge Rhopaloeides odorabile resulted in isolation of the bacterial strain NW4327. Sponges infected with strain NW4327 exhibited high levels of external tissue necrosis, and the strain was re-isolated from infected sponges. A single morphotype, which had burrowed through the collagenous spongin fibres causing severe necrosis, was observed microscopically. Strain NW4327 was capable of degrading commercial preparations of azo-collagen, providing further evidence of its involvement in spongin fibre necrosis, Strain NW4327 disrupted the microbial community associated with R. odorabile and was able to infect and kill healthy sponge tissue. 16S rRNA sequence analysis revealed that strain NW4327 is a novel member of the alpha-proteobacteria.

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Third-instar nymphs of the Australian assassin bug, Pristhesancus plagipennis (Walker), were released into cotton plots at two release densities and two crop growth stages to test their biological control potential. Release rates of 2 and 5 nymphs per metre row resulted in field populations of 0.51 and 1.38 nymphs per metre row, respectively, indicating that over 70% of nymphs died or emigrated within two weeks of release. Effective release rates of 1.38 nymphs per metre row reduced the number of Helicoverpa spp. larvae in the plots for a 7-week period. Crop yields were significantly greater in the plots to which P. plagipennis nymphs were released, with the effective release rate of 1.38 nymphs per metre row providing equivalent yields as insecticide treated plots. The data suggest that P. plagipennis has the capacity to reduce Helicoverpa spp. larvae densities in cotton crops when augmented through inundative release.

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Endothelial function plays a key role in the local regulation of vascular tone. Alterations in endothelial function may result in impaired release of endothelium-derived relaxing factors or increased release of endothelium-derived contracting factors. Heart failure may impair endothelial function by means of reduced synthesis and release of nitric oxide (NO) or by increased degradation of NO and increased production of endothelin-1. Endothelial dysfunction may worsen heart function by means of peripheral effects, causing increased afterload and central effects such as myocardial ischemia and inducible nitric oxide synthase (iNOS)-induced detrimental effects. Evidence from clinical studies has suggested that there is a correlation between decreased endothelial function and increasing severity of congestive heart failure (CHF). Treatments that improve heart function may also improve endothelial dysfunction. The relationship between endothelial dysfunction and heart failure may be masked by the stage of endothelial dysfunction, the location of vessels being tested, and the state of endothelial-dependent vasodilatation response.

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Human R183H-GH causes autosomal dominant GH deficiency type II. Because we show here that the mutant hormone is fully bioactive, we have sought to locate an impairment in its progress through the secretory pathway as assessed by pulse chase experiments. Newly synthesized wild-type and R183H-GH were stable when expressed transiently in AtT20 cells, and both formed equivalent amounts of Lubrol-insoluble aggregates within 40 min after synthesis. There was no evidence for intermolecular disulfide bond formation in aggregates of wild-type hormone or the R183H mutant. Both wildtype and R183H-GH were packaged into secretory granules, assessed by the ability of 1 mm BaCl2 to stimulate release and by immunocytochemistry. The mutant differed from wildtype hormone in its retention in the cells after packaging into secretory granules; 50% more R183H-GH than wild-type aggregates were retained in AtT20 cells 120 min after synthesis, and stimulated release of R183H-GH or a mixture of R183H-GH and wild-type that had been retained in the cell was reduced. The longer retention of R183H-GH aggregates indicates that a single point mutation in a protein contained in secretory granules affects the rate of secretory granule release.

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Pulmonary hypertension is associated with various alterations in 5-hydroxytryptamine (5-HT) physiology. In this study in platelets from hypoxic pulmonary hypertensive rats (10% O-2; 1 week) and normoxic rats (room air), (i) initial rates of specific [H-3]5-HT uptake were measured and (ii) potentiation of collagen- and ADP-induced aggregation by 5-HT was quantified. The platelet count was almost halved in hypoxic rats. In uptake experiments, there was a decrease in 5-HT uptake in platelets from hypoxic compared with normoxic rats, due to a 36% reduction in the maximal initial rate of uptake. The aggregation experiments showed that 5-HT (1-100 muM) increased the magnitude of responses to collagen and the duration of responses to ADP, but there was no difference between hypoxic and normoxic rats. Abnormalities in platelet function may conceivably lead to increases in plasma 5-HT levels in hypoxic pulmonary hypertension, but are unlikely to aggravate pulmonary thromboembolism. (C) 2002 Elsevier Science B.V. All rights reserved.

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The platelet inhibitory effects of the nitric oxide (NO) donor drug MAHMA NONOate ((Z-1-{N-methyl-N-[6-(N-methylammoniohexyl)amino] diazen-1-ium-1,2-diolate) were examined in anaesthetised rats and compared with those of S-nitrosoglutathione (GSNO; an S-nitrosothiol). Bolus administration of the aggregating agent ADP dose-dependently reduced the number of circulating free platelets. Intravenous infusions of MAHMA NONOate (3-30 nmol/kg/min) dose-dependently inhibited the effect of 0.3 mumol/kg ADP. MAHMA NONOate was approximately 10-fold more potent than GSNO. MAHMA NONOate (0.3-10 nmol/kg/min) also reduced systemic artery pressure and was again 10-fold more potent than GSNO. Thus MAHMA NONOate has both platelet inhibitory and vasodepressor effects in vivo. The dose ranges for these two effects overlapped, although blood pressure was affected at slightly lower doses. The platelet inhibitory effects compared favourably with those of GSNO, even though NONOates generate free radical NO which, in theory, could have been scavenged by haemoglobin. Therefore platelet inhibition may be a useful therapeutic property of NONOates. (C) 2003 Elsevier B.V. All rights reserved.