Interferometric probes of ultrarelativistic nuclear collisions

We suggest that pion and kaon interlerometry are complementary probes that help differentiate hadronic resonance gas from plasma dynamical models. We also discuss how interferometry could be used to test the presence of resonances at AGS energies. Finally, we study the A dependence of interferometry in the resonance model at 200 A GeV. © 1991.

Fluorescence in situ hybridization with rDNA probes on chromosomes of two nucleolus organizer region phenotypes of a species of Eigenmannia (Pisces, Gymnotoidei, Sternopygidae)

Nucleolus organizer regions (NORs) were analysed in two related and geographically close populations of Eigenmannia sp.1 (Pisces, Gymnotoidei, Sternopygidae) using silver staining and fluorescence in situ hybridization (FISH). The two populations differed in their AS-NOR phenotypes, displaying fixed differences in the NOR-bearing chromosome pairs. FISH with rDNA probes showed that these differences were due to the location of rDNA cistrons. This finding, showing fixed NOR differences between two populations belonging to the same species in a connected river system, is highly significant in terms of evolutionary change, possibly indicating an initial step of genetic differentiation. This result also has important implications from the cytosystematic point of view, as NORs usually have a very constant karyotypic location in fish species and have been used as species-specific chromosome markers.

Two short peptides including segments of subunit A of Escherichia coli DNA gyrase as potential probes to evaluate the antibacterial activity of quinolones

Quinolones constitute a family of compounds with a potent antibiotic activity. The enzyme DNA gyrase, responsible for the replication and transcription processes in DNA of bacteria, is involved in the mechanism of action of these drugs. In this sense, it is believed that quinolones stabilize the so-called 'cleavable complex' formed by DNA and gyrase, but the whole process is still far from being understood at the molecular level. This information is crucial in order to design new biological active products. As an approach to the problem, we have designed and synthesized low molecular weight peptide mimics of DNA gyrase. These peptides correspond to sequences of the subunit A of the enzyme from Escherichia coli, that include the quinolone resistance-determining region (positions 75-92) and a segment containing the catalytic Tyr-122 (positions 116-130). The peptide mimic of the non-mutated enzyme binds to ciprofloxin (CFX) only when DNA and Mg2+ were present (Kd = 1.6 × 10 -6 m), a result previously found with DNA gyrase. On the other hand, binding was reduced when mutations of Ser-83 to Leu-83 and Asp-87 to Asn-87 were introduced, a double change previously found in the subunit A of DNA gyrase from several CFX-resistant clinical isolates of E. coli. These results suggest that synthetic peptides designed in a similar way to that described here can be used as mimics of gyrases (topoisomerases) in order to study the binding of the quinolone to the enzyme-DNA complex as well as the mechanism of action of these antibiotics. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.

The devious maze of the international order: the importation of reforms

Includes bibliography

Are NORs Always Located on Homeologous Chromosomes? A FISH Investigation with rDNA and Whole Chromosome Probes in Gymnotus Fishes (Gymnotiformes)

Gymnotus (Gymnotiformes, Gymnotidae) is the most diverse known Neotropical electric knife fish genus. Cytogenetic studies in Gymnotus demonstrate a huge karyotypic diversity for this genus, with diploid numbers ranging from 34 to 54. The NOR are also variable in this genus, with both single and multiple NORs described. A common interpretation is that the single NOR pair is a primitive trait while multiple NORs are derivative. However this hypothesis has never been fully tested. In this report we checked if the NOR-bearing chromosome and the rDNA site are homeologous in different species of the genus Gymnotus: G. carapo (2n = 40, 42, 54), G. mamiraua (2n = 54), G. arapaima (2n = 44), G. sylvius (2n = 40), G. inaequilabiatus (2n = 54) and G. capanema (2n = 34), from the monophyletic group G. carapo (Gymnotidae-Gymnotiformes), as well as G. jonasi (2n = 52), belonging to the G1 group. They were analyzed with Fluorescence in situ hybridization (FISH) using 18S rDNA and whole chromosome probes of the NOR-bearing chromosome 20 (GCA20) of G. carapo (cytotype 2n = 42), obtained by Fluorescence Activated Cell Sorting. All species of the monophyletic G. carapo group show the NOR in the same single pair, confirmed by hybridization with CGA20 whole chromosome probe. In G. jonasi the NORs are multiple, and located on pairs 9, 10 and 11. In G. jonasi the GCA20 chromosome probe paints the distal half of the long arm of pair 7, which is not a NOR-bearing chromosome. Thus these rDNA sequences are not always in the homeologous chromosomes in different species thus giving no support to the hypothesis that single NOR pairs are primitive traits while multiple NORs are derived. The separation of groups of species in the genus Gymnotus proposed by phylogenies with morphologic and molecular data is supported by our cytogenetic data. © 2013 Milhomem et al.

Ethopharmacological analysis of the open elevated plus-maze in mice

Exposure of rodents to an open elevated plus-maze (oEPM) elicits antinociception and increases plasma corticosterone levels. However, no studies have yet assessed the defensive behaviour repertoire of animals in this modified test. In Experiment 1, factor analysis was employed to characterise the behavioural profile of mice exposed to the oEPM. Experiments 2 and 3 assessed the effects of acute alprazolam (0.5-1.5. mg/kg; diazepam 0.5-1.5. mg/kg), pentylenetetrazole (10.0-30.0. mg/kg), yohimbine (2.0-6.0. mg/kg), mCPP (0.3-3.0. mg/kg), and acute and chronic fluoxetine (10.0-30.0. mg/kg) and imipramine (1.0-15.0. mg/kg) on behaviours identified in Experiment 1. The factor analyses revealed that behaviour in the oEPM can largely (77% total variance) be accounted for in terms of 3 factors: factor 1 ('. depth exploration'; e.g. head-dipping on the arms), factor 2 ('. cautious exploration of arms'; e.g. flatback approach), and factor 3 ('. risk assessment'; stretched attend postures - SAP). Experiments 2 and 3 showed that, over the dose range used, alprazolam selectively attenuated all measures of defensiveness. Similar, though more modest, effects were seen with diazepam. Confirming the intensity of the emotional response to the oEPM (nociceptive, endocrine and behavioural), relatively few significant behavioural changes were seen in response to the anxiogenic compounds tested. Although acute fluoxetine or imipramine treatment failed to modify behaviour in the oEPM, chronic fluoxetine (but not chronic imipramine) attenuated total flat back approach and increased head dipping outside the central square. Together, the results indicate that the oEPM induces behavioural defensive responses that are sensitive to alprazolam and chronic fluoxetine. © 2013 Elsevier B.V.

Effect of the bone marrow cell transplantation on elevated plus-maze performance in hippocampal-injured mice

Several reports have shown that the hippocampus plays an important role in different aspects of the emotional control. There is evidence that lesions in this structure cause behavioral disinhibition, with reduction of reactions expressing fear and anxiety. Thus, to portray the aptitude of cell therapy to abrogate injuries of hippocampal tissue, we examined the behavioral effects of bone marrow mononuclear cells (BMMCs) transplantation on C57BL/6 mice that had the hippocampus damaged by electrolytic lesion. For this purpose, mice received, seven days after bilateral electrolytic lesion in the dorsal hippocampus, culture medium or BMMCs expressing the enhanced green fluorescent protein (EGFP) transgene. One week after transplantation, animals were tested in the elevated plus-maze (EPM). On the whole, three assessment sessions in the EPM were carried out, with seven days separating each trial. Thirty-five days after the induction of injury, mice were sacrificed and their brains removed for immunohistochemistry. The behavioral evaluation showed that the hippocampal lesion caused disinhibition, an effect which was slightly lessened, from the second EPM test, in transplanted subjects. On the other hand, immunohistochemical data revealed an insignificant presence of EGFP+ cells inside the brains of injured mice. In view of such scenario, we hypothesized that the subtle rehabilitation of the altered behavior might be a result from a paracrine effect from the transplanted cells. This might have been caused by the release of bioactive factors capable of boosting endogenous recuperative mechanisms for a partial regaining of the hippocampal functions. © 2013 Elsevier B.V.

The effects of diazepam on the elevated T-maze are dependent on the estrous cycle of rats

In order to determine the modulation of anxiolytic and panicolytic-like effects of diazepam by the hormonal cycle of female rats, male and female rats – the latter divided per estrous cycle phase (estrus, diestrus, metaestrus and proestrus) – were tested in the elevated T-maze, a behavioral model of panic and anxiety. Diazepam (0.5, 1.0 and 2.0 mg/kg) or saline solution was injected in individual animals that were submitted to one session in the elevated T-maze 25 min after drug/saline administration. The test consisted of three avoidance trials and one escape trial, separated by a 30 s interval, during which the animals were isolated in individual cages. The avoidance trials began with the animal being placed at the end of the maze's enclosed arm. The time necessary for the animal to leave the central square was considered as the response's latency. The trials that exceeded 300 s were considered as failures. Results demonstrate a decrease in the effects of diazepam in inhibitory avoidance (anxiety) trials in females in diestrus and proestrus, but no relation of gender or estrous cycle on diazepam effects on escape trials (fear). The results support the hypothesis that down-regulation of GABAA receptors by activation of nuclear estrogen receptors and induction of PKC-mediated GABAA receptor phosphorylation by activation of surface estrogen receptors in raphe neurons underlie the modulation of diazepam sensitivity by estrogen.

Role of TRPV1 channels of the dorsal periaqueductal gray in the modulation of nociception and open elevated plus maze-induced antinociception in mice

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hydroxythiazole-Based Fluorescent Probes for Fluoride Ion Detection

This work describes the synthesis of five O-silyloxy-1,3-thiazoles and their use as fast-response turn-on probes for fluoride ion detection in polar aprotic solvents and in aqueous cetyltrimethylammonium bromide micellar medium. The fluoride-triggered deprotection of these silyl ethers results in ca. 180-nm shifts in the fluorescence emission wavelengths. All compounds are suitable for the detection of fluoride ions with a detection limit in DMSO of 107 mol?L1; derivatives containing a 2-pyridyl moiety in the thiazole system are more efficient than those with a 3- or 4-pyridyl moiety. Typical anionic interferents, such as acetate or chloride, are not detected by O-silyloxy-1,3-thiazoles, making these compounds very specific for fluoride.

Activation of 5-HT2C receptors in the dorsal periaqueductal gray increases antinociception in mice exposed to the elevated plus-maze

Several findings have pointed to the role of the dorsal periaqueductal gray (dPAG) serotonin 5-HT1A and 5-HT2(A-C) receptor subtypes in the modulation of defensive behavior in animals exposed to the elevated plus-maze (EPM). Besides displaying anxiety-like behavior, rodents also exhibit antinociception in the EPM. This study investigated the effects of intra-dPAG injections of 5-HT1A and 5-HT2B/2C receptor ligands on EPM-induced antinociception in mice. Male Swiss mice received 0.1 mu l intra-dPAG injections of vehicle, 5.6 and 10 nmol of 8-OHDPAT, a 5-HT1A receptor agonist (Experiment 1), or 0.01, 0.03 and 0.1 nmol of mCPP, a 5-HT2B/2C receptor agonist (Experiment 2). Five minutes later, each mouse received an intraperitoneal injection of 0.6% acetic acid (0.1 ml/10 g body weight; nociceptive stimulus) and was individually confined in the open (OA) or enclosed (EA) arms of the EPM for 5 min, during which the number of abdominal writhes induced by the acetic acid was recorded. While intra-dPAG injection of 8-OHDPAT did not change open-arm antinociception (OAR). mCPP (0.01 nmol) enhanced it. Combined injections of ketanserin (10 nmol/0.1 mu l), a 5-HT2A/2C receptor antagonist, and 0.01 nmol of mCPP (Experiment 3), selectively and completely blocked the OAR enhancement induced by mCPP. Although intra-dPAG injection of mCPP (0.01 nmol) also produced antinociception in EA-confined mice (Experiment 2), this effect was not confirmed in Experiment 3. Moreover, no other compound changed the nociceptive response in EA-confined animals. These results suggest that the 5-HT2C receptors located within the PAG play a role in this type of environmentally induced pain inhibition in mice. (c) 2012 Elsevier B.V. All rights reserved.

Constraining H-0 in general dark energy models from Sunyaev-Zeldovich/X-ray technique and complementary probes

In accelerating dark energy models, the estimates of the Hubble constant, Ho, from Sunyaev-Zerdovich effect (SZE) and X-ray surface brightness of galaxy clusters may depend on the matter content (Omega(M)), the curvature (Omega(K)) and the equation of state parameter GO. In this article, by using a sample of 25 angular diameter distances of galaxy clusters described by the elliptical beta model obtained through the SZE/X-ray technique, we constrain Ho in the framework of a general ACDM model (arbitrary curvature) and a flat XCDM model with a constant equation of state parameter omega = p(x)/rho(x). In order to avoid the use of priors in the cosmological parameters, we apply a joint analysis involving the baryon acoustic oscillations (BA()) and the (MB Shift Parameter signature. By taking into account the statistical and systematic errors of the SZE/X-ray technique we obtain for nonflat ACDM model H-0 = 74(-4.0)(+5.0) km s(-1) Mpc(-1) (1 sigma) whereas for a fiat universe with constant equation of state parameter we find H-0 = 72(-4.0)(+5.5) km s(-1) Mpc(-1)(1 sigma). By assuming that galaxy clusters are described by a spherical beta model these results change to H-0 = 6(-7.0)(+8.0) and H-0 = 59(-6.0)(+9.0) km s(-1) Mpc(-1)(1 sigma), respectively. The results from elliptical description are in good agreement with independent studies from the Hubble Space Telescope key project and recent estimates based on the Wilkinson Microwave Anisotropy Probe, thereby suggesting that the combination of these three independent phenomena provides an interesting method to constrain the Bubble constant. As an extra bonus, the adoption of the elliptical description is revealed to be a quite realistic assumption. Finally, by comparing these results with a recent determination for a, flat ACDM model using only the SZE/X-ray technique and BAO, we see that the geometry has a very weak influence on H-0 estimates for this combination of data.

Solvation in aqueous binary mixtures: consequences of the hydrophobic character of the ionic liquids and the solvatochromic probes

Information on the solvation in mixtures of water, W, and the ionic liquids, ILs, 1-allyl-3-R-imidazolium chlorides; R = methyl, 1-butyl, and 1-hexyl, has been obtained from the responses of the following solvatochromic probes: 2,6-dibromo-4-[(E)-2-(1-R-pyridinium-4-yl)ethenyl] phenolate, R = methyl, MePMBr2; 1-octyl, OcPMBr(2), and the corresponding quinolinium derivative, MeQMBr(2). A model developed for solvation in binary mixtures of W and molecular solvents has been extended to the present mixtures. Our objective is to assess the relevance to solvation of hydrogen-bonding and the hydrophobic character of the IL and the solvatochromic probe. Plots of the medium empirical polarity, E-T(probe) versus its composition revealed non-ideal behavior, attributed to preferential solvation by the IL and, more efficiently, by the IL-W hydrogen-bonded complex. The deviation from linearity increases as a function of increasing number of carbon atoms in the alkyl group of the IL, and is larger than that observed for solvation by W plus molecular solvents (1-propanol and 2-(1-butoxy)ethanol) that are more hydrophobic than the ILs investigated. This enhanced deviation is attributed to the more organized structure of the ILs proper, which persists in their aqueous solutions. MeQMBr(2) is more susceptible to solvent lipophilicity than OcPMBr(2), although the former probe is less lipophilic. This enhanced susceptibility agrees with the important effect of annelation on the contributions of the quinonoid and zwitterionic limiting structures to the ground and excited states of the probe, hence on its response to both medium composition and lipophilicity of the IL.

EVALUATION OF MICROBIAL GROWTH ON SINGLE-USE VITRECTOMY PROBES REPROCESSED IN HEALTHCARE PRACTICE

The aim of this study was to evaluate the microbial growth on single-use vitrectomy probes reprocessed in healthcare practice. We investigated nine vitrectomy probes that had been reused and reprocessed using different methods. The samples were sectioned, individually, in portions of 3.5 cm, totaling 979 sampling units (extensions, connectors and vitrectomy cutters), which were inoculated in culture medium and incubated at 37 C for 14 days. The results showed microbial growth on 57 (5.8%) sample units, 25 of which had been sterilized using ethylene oxide, 16 by hydrogen peroxide plasma, and 16 by low-temperature steam and formaldehyde. Seventeen microbial species were identified. The most prevalent were: Micrococcus spp., coagulase-negative Staphylococcus, Pseudomonas spp., and Bacillus subtilis. The reuse of single-use vitrectomy probes was shown to be unsafe, therefore this practice is not recommended.