19 resultados para partition in micellar phase
Resumo:
Centrifugal countercurrent distribution (CCCD) in an aqueous two-phase system (TPS) is a resolute technique revealing sperm heterogeneity and for the estimation of the fertilizing potential of a given semen sample. However, separated sperm subpopulations have never been tested for their fertilizing ability yet. Here, we have compared sperm quality parameters and the fertilizing ability of sperm subpopulations separated by the CCCD process from ram semen samples maintained at 20 degrees C or cooled down to 5 degrees C. Total and progressive sperm motility was evaluated by computer-assisted analysis using a CASA system and membrane integrity was evaluated by flow cytometry by staining with CFDA/Pl. The capacitation state, staining with chlortetracycline, and apoptosis-related markers, such as phosphatidylserine (PS) translocation detected with Annexin V. and DNA damage detected by the TUNEL assay, were determined by fluorescence microscopy. Additionally, the fertilizing ability of the fractionated subpopulations was comparative assessed by zona binding assay (ZBA). CCCD analysis revealed that the number of spermatozoa displaying membrane and DNA alterations was higher in samples chilled at 5 degrees C than at 20 degrees C. which can be reflected in the displacement to the left of the CCCD profiles. The spermatozoa located in the central and right chambers (more hydrophobic) presented higher values (P<0.01) of membrane integrity, lower PS translocation (P<0.05) and DNA damage (P<0.001) than those in the left part of the profile, where apoptotic markers were significantly increased and the proportion of viable non-capacitated sperm was reduced. We have developed a new protocol to recover spermatozoa from the CCCD fractions and we proved that these differences were related with the fertilizing ability determined by ZBA, because we found that the number of spermatozoa attached per oocyte was significantly higher for spermatozoa recovered from the central and right chambers, in both types of samples. This is the first time, to our knowledge that sperm recovered from a two-phase partition procedure are used for fertilization assays. These results open up new possibilities for using specific subpopulations of sperm for artificial insemination or in vitro fertilization, not only regarding better sperm quality but also certain characteristics such as subpopulations enriched in spermatozoa bearing X or Y chromosome that we have already isolated or any other feature. (C) 2011 Elsevier B.V. All rights reserved.
Resumo:
In this retrospective study we evaluated the pretherapeutic mRNA expression of the hOCT1 (human organic cation transporter 1) gene in patients with chronic-phase (CP) chronic myeloid leukemia (CML) who varied in terms of their response to imatinib (IM). hOCT1 mRNA was quantified by real-time PCR. Patients were classified as expressing either high (n = 44) or low hOCT1 mRNA (n = 44). The complete cytogenetic response rates observed at 6, 12 and 18 months were 47.7, 84.1 and 91%, respectively, in patients with high hOCT1 mRNA and 47.5, 81.8 and 86.3%, respectively, in patients with low hOCT1 transcripts. The major molecular response rates were not significantly different between patients with high and low hOCT1 mRNA after 6 months of therapy (22.7 vs. 9.1%; p = 0.07), but they were significantly different after 12 months (54.5 vs. 31.8%; p = 0.026) and 18 months (77.2 vs. 56.8%; p = 0.034). Complete molecular responses were observed in 5 patients with low and 17 patients with high hOCT1 mRNA (p = 0.003). The 5-year event-free and overall survival analyses revealed no significant differences between the groups. These data imply that knowledge of the pretherapeutic level of hOCT1 could be a useful marker to predict IM therapy outcome in treatment-naive CP CML patients. Copyright (C) 2012 S. Karger AG, Basel
Resumo:
In this paper, we perform a thorough analysis of a spectral phase-encoded time spreading optical code division multiple access (SPECTS-OCDMA) system based on Walsh-Hadamard (W-H) codes aiming not only at finding optimal code-set selections but also at assessing its loss of security due to crosstalk. We prove that an inadequate choice of codes can make the crosstalk between active users to become large enough so as to cause the data from the user of interest to be detected by other user. The proposed algorithm for code optimization targets code sets that produce minimum bit error rate (BER) among all codes for a specific number of simultaneous users. This methodology allows us to find optimal code sets for any OCDMA system, regardless the code family used and the number of active users. This procedure is crucial for circumventing the unexpected lack of security due to crosstalk. We also show that a SPECTS-OCDMA system based on W-H 32(64) fundamentally limits the number of simultaneous users to 4(8) with no security violation due to crosstalk. More importantly, we prove that only a small fraction of the available code sets is actually immune to crosstalk with acceptable BER (<10(-9)) i.e., approximately 0.5% for W-H 32 with four simultaneous users, and about 1 x 10(-4)% for W-H 64 with eight simultaneous users.
Resumo:
Objective: To assess the risk factors for delayed diagnosis of uterine cervical lesions. Materials and Methods: This is a case-control study that recruited 178 women at 2 Brazilian hospitals. The cases (n = 74) were composed of women with a late diagnosis of a lesion in the uterine cervix (invasive carcinoma in any stage). The controls (n = 104) were composed of women with cervical lesions diagnosed early on (low-or high-grade intraepithelial lesions). The analysis was performed by means of logistic regression model using a hierarchical model. The socioeconomic and demographic variables were included at level I (distal). Level II (intermediate) included the personal and family antecedents and knowledge about the Papanicolaou test and human papillomavirus. Level III (proximal) encompassed the variables relating to individuals' care for their own health, gynecologic symptoms, and variables relating to access to the health care system. Results: The risk factors for late diagnosis of uterine cervical lesions were age older than 40 years (odds ratio [OR] = 10.4; 95% confidence interval [CI], 2.3-48.4), not knowing the difference between the Papanicolaou test and gynecological pelvic examinations (OR, = 2.5; 95% CI, 1.3-4.9), not thinking that the Papanicolaou test was important (odds ratio [OR], 4.2; 95% CI, 1.3-13.4), and abnormal vaginal bleeding (OR, 15.0; 95% CI, 6.5-35.0). Previous treatment for sexually transmissible disease was a protective factor (OR, 0.3; 95% CI, 0.1-0.8) for delayed diagnosis. Conclusions: Deficiencies in cervical cancer prevention programs in developing countries are not simply a matter of better provision and coverage of Papanicolaou tests. The misconception about the Papanicolaou test is a serious educational problem, as demonstrated by the present study.
Resumo:
The bioactive naphtoquinone lapachol was studied in vitro by a biomimetic model with Jacobsen catalyst (manganese(III) salen) and iodosylbenzene as oxidizing agent. Eleven oxidation derivatives were thus identified and two competitive oxidation pathways postulated. Similar to Mn(III) porphyrins, Jacobsen catalyst mainly induced the formation of para-naphtoquinone derivatives of lapachol, but also of two ortho-derivatives. The oxidation products were used to develop a GC MS (SIM mode) method for the identification of potential phase I metabolites in vivo. Plasma analysis of Wistar rats orally administered with lapachol revealed two metabolites, alpha-lapachone and dehydro-alpha-lapachone. Hence, the biomimetic model with a manganese salen complex has evidenced its use as a valuable tool to predict and elucidate the in vivo phase I metabolism of lapachol and possibly also of other bioactive natural compounds. (C) 2012 Elsevier Masson SAS. All rights reserved.
Resumo:
In this conference we report cross sections for elastic collisions of low-energy electrons with the HCOOH…(H2O)n complexes, with n = 1, 2 and 3. The scattering cross sections were computed with the Schwinger multichannel method [K. Takatsuka and V. McKoy, Phys. Rev. A 24 , 2473 (1981); Phys. Rev. A 30 , 1734 (1984)] with pseudopotentials [M. H. F. Bettega, L. G. Ferreira, and M. A. P. Lima, Phys. Rev. A 47, 1111 (1993)] in the static-exchange and static-exchange plus polarization approximations, for energies from 0.5 eV to 6 eV. We considered some diÆerent hydrogen-bonded structures for the complexes that were generated with classical Monte Carlo simulations [K. Coutinho and S. Canuto, J. Chem. Phys. 113, 9132, (2000)]. The aim of this work is to investigate the effect of the surrounding water molecules on the π* shape resonance of the solute. Previous theoretical and experimental studies carried out in the gas phase reported a π* state for HCOOH at around 1.9 eV. For the n = 1 case and for all complexes, the stabilization of the resonance was observed (it appears at lower energy compared to the value obtained in the gas phase), as reported previously for the CH2O…H2O complexes [T. C. Freitas, M. A. P. Lima, S. Canuto, and M. H. F. Bettega, Phys. Rev. A 80, 062710 (2009)]. This result indicates that the presence of the solvent may affect the processes related to the π* state, such as the molecular dissociation by electron impact. For the n = 2 case we have observed both stabilization and destabilization of the π* resonance, that is associated with the hydrogen bond donor or acceptor role of the water molecules in the complexes. For the n = 3 case, preliminary static-exchange results show the stabilization of the π* state. We propose an explanation of the stabilization/destabilization of the π* state in terms of the polarization of the solute due to the surrounding water molecules and the net charge in the solute.
Resumo:
Introduction: Denosumab, a fully human anti-RANKL monoclonal antibody, reduces the incidence of skeletal-related events in patients with bone metastases from solid tumors. We present survival data for the subset of patients with lung cancer, participating in the phase 3 trial of denosumab versus zoledronic acid (ZA) in the treatment of bone metastases from solid tumors (except breast or prostate) or multiple myeloma. Methods: Patients were randomized 1:1 to receive monthly subcutaneous denosumab 120 mg or intravenous ZA 4 mg. An exploratory analysis, using Kaplan-Meier estimates and proportional hazards models, was performed for overall survival among patients with non-small-cell lung cancer (NSCLC) and SCLC. Results: Denosumab was associated with improved median overall survival versus ZA in 811 patients with any lung cancer (8.9 versus 7.7 months; hazard ratio [HR] 0.80) and in 702 patients with NSCLC (9.5 versus 8.0 months; HR 0.78) (p = 0.01, each comparison). Further analysis of NSCLC by histological type showed a median survival of 8.6 months for denosumab versus 6.4 months for ZA in patients with squamous cell carcinoma (HR 0.68; p = 0.035). Incidence of overall adverse events was balanced between treatment groups; serious adverse events occurred in 66.0% of denosumab-treated patients and 72.9% of ZA-treated patients. Cumulative incidence of osteonecrosis of the jaw was similar between groups (0.7% denosumab versus 0.8% ZA). Hypocalcemia rates were 8.6% with denosumab and 3.8% with ZA. Conclusion: In this exploratory analysis, denosumab was associated with improved overall survival compared with ZA, in patients with metastatic lung cancer.
Resumo:
Validation of parentage and horse breed registries through DNA typing relies on estimates of random match probabilities with DNA profiles generated from multiple polymorphic loci. Of the twenty-seven microsatellite loci recommended by the International Society for Animal Genetics for parentage testing in Thoroughbred horses, eleven are located on five chromosomes. An important aspect in determining combined exclusion probabilities is the ascertainment of the genetic linkage status of syntenic markers, which may affect reliable use of the product rule in estimating random match probabilities. In principle, linked markers can be in gametic phase disequilibrium (GD). We aimed at determining the extent, by frequency and strength, of GD between the HTG4 and HMS3 multiallelic loci, syntenic on chromosome 9. We typed the qualified offspring (n (1) = 27; n (2) = 14) of two Quarter Bred stallions (registered by the Brazilian Association of Quarter Horse Breeders) and 121 unrelated horses from the same breed. In the 41 informative meioses analyzed, the frequency of recombination between the HTG4 and HMS3 loci was 0.27. Consistent with genetic map distances, this recombination rate does not fit to the theoretical distribution for independently segregated markers. We estimated sign-based D' coefficients as a measure of GD, and showed that the HTG4 and HMS3 loci are in significant, yet partial and weak, disequilibrium, with two allele pairs involved (HTG4*M/HMS3*P, D'(+) = 0.6274; and HTG4*K/HMS3*P, D'(-) = -0.6096). These results warn against the inadequate inclusion of genetically linked markers in the calculation of combined power of discrimination for Thoroughbred parentage validation.
Resumo:
Using giant unilamellar vesicles (GUVs) made from POPC. DPPC, cholesterol and a small amount of a porphyrin-based photosensitizer that we name PE-porph, we investigated the response of the lipid bilayer under visible light, focusing in the formation of domains during the lipid oxidation induced by singlet oxygen. This reactive species is generated by light excitation of PE-porf in the vicinity of the membrane, and thus promotes formation of hydroperoxides when unsaturated lipids and cholesterol are present. Using optical microscopy we determined the lipid compositions under which GUVs initially in the homogeneous phase displayed Lo-Ld phase separation following irradiation. Such an effect is attributed to the in situ formation of both hydroperoxized POPC and cholesterol. The boundary line separating homogeneous Lo phase and phase coexistence regions in the phase diagram is displaced vertically towards the higher cholesterol content in respect to ternary diagram of POPC:DPPC:cholesterol mixtures in the absence of oxidized species. Phase separated domains emerge from sub-micrometer initial sizes to evolve over hours into large Lo-Ld domains completely separated in the lipid membrane. This study provides not only a new tool to explore the kinetics of domain formation in mixtures of lipid membranes, but may also have implications in biological signaling of redox misbalance. (C) 2011 Elsevier B.V. All rights reserved.
Resumo:
Some phase space transport properties for a conservative bouncer model are studied. The dynamics of the model is described by using a two-dimensional measure preserving mapping for the variables' velocity and time. The system is characterized by a control parameter epsilon and experiences a transition from integrable (epsilon = 0) to nonintegrable (epsilon not equal 0). For small values of epsilon, the phase space shows a mixed structure where periodic islands, chaotic seas, and invariant tori coexist. As the parameter epsilon increases and reaches a critical value epsilon(c), all invariant tori are destroyed and the chaotic sea spreads over the phase space, leading the particle to diffuse in velocity and experience Fermi acceleration (unlimited energy growth). During the dynamics the particle can be temporarily trapped near periodic and stable regions. We use the finite time Lyapunov exponent to visualize this effect. The survival probability was used to obtain some of the transport properties in the phase space. For large epsilon, the survival probability decays exponentially when it turns into a slower decay as the control parameter epsilon is reduced. The slower decay is related to trapping dynamics, slowing the Fermi Acceleration, i.e., unbounded growth of the velocity.
Resumo:
Iron has been suggested to reduce the erosive potential of cola drinks in vitro. Objective: The aim of this study was to evaluate in situ the effect of ferrous sulfate supplementation on the inhibition of the erosion caused by a cola drink. Material and Methods: Ten adult volunteers participated in a crossover protocol conducted in two phases of 5 days, separated by a washout period of 7 days. In each phase, they wore palatal devices containing two human enamel and two human dentin blocks. The volunteers immersed the devices for 5 min in 150 mL of cola drink (Coca-Cola (TM), pH 2.6), containing ferrous sulfate (10 mmol/L) or not (control), 4 times per day. The effect of ferrous sulfate on the inhibition of erosion was evaluated by profilometry (wear). Data were analyzed by paired t tests (p<0.05). Results: The mean wear (+/- se) was significantly reduced in the presence of ferrous sulfate, both for enamel (control: 5.8 +/- 1.0 mu m; ferrous sulfate: 2.8 +/- 0.6 mu m) and dentin (control: 4.8 +/- 0.8 mu m; ferrous sulfate: 1.7 +/- 0.7 mu m). Conclusions: The supplementation of cola drinks with ferrous sulfate can be a good alternative for the reduction of their erosive potential. Additional studies should be done to test if lower ferrous sulfate concentrations can also have a protective effect as well as the combination of ferrous sulfate with other ions.
Resumo:
The aim of this study was to evaluate the erosive potential of orange juice modified with food-approved additives: 0.4 g/l of calcium (Ca) from calcium lactate pentahydrate, 0.2 g/l of linear sodium polyphosphate (LPP) or their combination (Ca+LPP) were added to a commercially available orange juice (negative control, C-). A commercially available calcium-modified orange juice (1.6 g/l of calcium) was the positive control (C+). These juices were tested using a short-term erosion in situ model, consisting of a five-phase, single-blind crossover clinical trial involving 10 subjects. In each phase, subjects inserted custom-made palatal appliances containing 8 bovine enamel specimens in the mouth and performed erosive challenges for a total of 0 (control), 10, 20, and 30 min. Two specimens were randomly removed from the appliances after each challenge period. Enamel surface microhardness was measured before and after the clinical phase and the percentage of surface microhardness change (%SMC) was determined. Before the procedures, in each phase, the subjects performed a taste test, where the juice assigned to that phase was blindly compared to C-. Overall, C+ showed the lowest %SMC, being the least erosive solution (p < 0.05), followed by Ca+LPP and Ca, which did not differ from each other (p > 0.05). LPP and C- were the most erosive solutions (p <0.05). Taste differences were higher for C+ (5/10 subjects) and Ca (4/10 subjects), but detectable in all groups, including C- (2/10 subjects). Calcium reduced the erosive potential of the orange juice, while no protection was observed for LPP. Copyright (C) 2012 S. Karger AG, Basel
Resumo:
Polymeric sensors with improved resistance to organic solvents were produced via the layer-by-layer thin film deposition followed by chemical cross-linking. According to UV-vis spectroscopy, the mass loss of polyaniline/poly(vinyl alcohol) and polyaniline/novolac-type resin based films deposited onto glass slides was less than 20% when they were submitted to successive immersions (up to 3,000 immersion cycles) into commercially available ethanol and gasoline fuel samples. Polyallylamine hydrochloride/nickel tetrasulfonated phthalocyanine films presented similar stability. The electrical responses assessed by impedance spectroscopy of films deposited onto Au-interdigitated microelectrodes were relatively unaffected after continuous or cyclic immersions into both fuels. After these studies, an array including these polymeric sensors was employed to detect adulteration in ethanol and gasoline samples. After principal component analysis, it was possible to conclude that the proposed sensor array is capable to discriminate with remarkable reproducibility ethanol samples containing different amounts of water or else gasoline samples containing different amounts of ethanol. In both examples, more than 90% of data variance was retained in the first principal component. For each type of sample, ethanol and gasoline, it was found a linear correlation between one of the principal components and the sample's composition. These findings allow one to conclude that these films present great potential for the development of reliable and low-cost sensors for fuel analysis in liquid phase.
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Using Fluorescence Recovery After Photobleaching, we investigate the Brownian motion of DNA rod-like fragments in two distinct anisotropic phases with a local nematic symmetry. The height of the measurement volume ensures the averaging of the anisotropy of the in-plane diffusive motion parallel or perpendicular to the local nematic director in aligned domains. Still, as shown in using a model specifically designed to handle such a situation and predicting a non-Gaussian shape for the bleached spot as fluorescence recovery proceeds, the two distinct diffusion coefficients of the DNA particles can be retrieved from data analysis. In the first system investigated (a ternary DNA-lipid lamellar complex), the magnitude and anisotropy of the diffusion coefficient of the DNA fragments confined by the lipid bilayers are obtained for the first time. In the second, binary DNA-solvent system, the magnitude of the diffusion coefficient is found to decrease markedly as DNA concentration is increased from isotropic to cholesteric phase. In addition, the diffusion coefficient anisotropy measured within cholesteric domains in the phase coexistence region increases with concentration, and eventually reaches a high value in the cholesteric phase.