670 research outputs found

    Molecular and Behavioral Differentiation among Brazilian Populations of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae)

    Get PDF
    Lutzomyia longipalpis is the main vector of visceral leishmaniasis in the Americas. There is strong evidence that L. longipalpis is a species complex, but there is still no consensus regarding the number of species occurring in Brazil. We combined molecular and behavioral analyses of a number of L. longipalpis populations in order to help clarify this question. This approach has allowed us to identify two main groups of populations in Brazil. One group probably represents a single species distributed mainly throughout the coastal regions of North and Northeast Brazil and whose males produce the same type of copulation song and pheromone. The second group is more heterogeneous, probably represented by a number of incipient species with different levels of genetic divergence among the siblings that produce different combinations of copulation songs and pheromones. The high level of complexity observed raises important questions concerning the epidemiological consequences of this incipient speciation process

    Entropy production and coarse graining of the climate fields in a general circulation model

    Get PDF
    We extend the analysis of the thermodynamics of the climate system by investigating the role played by processes taking place at various spatial and temporal scales through a procedure of coarse graining. We show that the coarser is the graining of the climatic fields, the lower is the resulting estimate of the material entropy production. In other terms, all the spatial and temporal scales of variability of the thermodynamic fields provide a positive contribution to the material entropy production. This may be interpreted also as that, at all scales, the temperature fields and the heating fields resulting from the convergence of turbulent fluxes have a negative correlation, while the opposite holds between the temperature fields and the radiative heating fields. Moreover, we obtain that the latter correlations are stronger, which confirms that radiation acts as primary driver for the climatic processes, while the material fluxes dampen the resulting fluctuations through dissipative processes. We also show, using specific coarse-graining procedures, how one can separate the various contributions to the material entropy production coming from the dissipation of kinetic energy, the vertical sensible and latent heat fluxes, and the large scale horizontal fluxes, without resorting to the full three-dimensional time dependent fields. We find that most of the entropy production is associated to irreversible exchanges occurring along the vertical direction, and that neglecting the horizontal and time variability of the fields has a relatively small impact on the estimate of the material entropy production. The approach presented here seems promising for testing climate models, for assessing the impact of changing their parametrizations and their resolution, as well as for investigating the atmosphere of exoplanets, because it allows for evaluating the error in the estimate of their thermodynamical properties due to the lack of high-resolution data. The findings on the impact of coarse graining on the thermodynamic fields on the estimate of the material entropy production deserve to be explored in a more general context, because they provide a way for understanding the relationship between forced fluctuations and dissipative processes in continuum systems

    Mucosal Leishmaniasis Caused by Leishmania (Viannia) braziliensis and Leishmania (Viannia) guyanensis in the Brazilian Amazon

    Get PDF
    Background: Leishmania (Viannia) braziliensis is a parasite recognized as the most important etiologic agent of mucosal leishmaniasis (ML) in the New World. In Amazonia, seven different species of Leishmania, etiologic agents of human Cutaneous Leishmaniasis, have been described. Isolated cases of ML have been described for several different species of Leishmania: L. (V.) panamensis, L. (V.) guyanensis and L. (L.) amazonensis. Methodology: Leishmania species were characterized by polymerase chain reaction (PCR) of tissues taken from mucosal biopsies of Amazonian patients who were diagnosed with ML and treated at the Tropical Medicine Foundation of Amazonas (FMTAM) in Manaus, Amazonas state, Brazil. Samples were obtained retrospectively from the pathology laboratory and prospectively from patients attending the aforementioned tertiary care unit. Results: This study reports 46 cases of ML along with their geographical origin, 30 cases caused by L. (V.) braziliensis and 16 cases by L. (V.) guyanensis. This is the first record of ML cases in 16 different municipalities in the state of Amazonas and of simultaneous detection of both species in 4 municipalities of this state. It is also the first record of ML caused by L. (V.) guyanensis in the states of Para, Acre, and Rondonia and cases of ML caused by L. (V.) braziliensis in the state of Rondonia. Conclusions/Significance: L. (V.) braziliensis is the predominant species that causes ML in the Amazon region. However, contrary to previous studies, L. (V.) guyanensis is also a significant causative agent of ML within the region. The clinical and epidemiological expression of ML in the Manaus region is similar to the rest of the country, although the majority of ML cases are found south of the Amazon River.SUFRAMA[016/2004

    Rivaroxaban for Preventing Venous Thromboembolism in High-Risk Ambulatory Patients with Cancer: Rationale and Design of the CASSINI Trial

    Get PDF
    Venous thromboembolism (VTE) is a frequent complication of cancer associated with morbidity, mortality, increased hospitalizations and higher health care costs. Cancer patients at increased risk for VTE can be identified using a validated risk assessment score, and the incidence of VTE can be reduced in high-risk settings using anticoagulation. Rivaroxaban is a potent, oral, direct, factor Xa inhibitor approved for the prevention and treatment of thromboembolic events, including VTE. CASSINI is a double-blind, randomized, parallel-group, multicentre study comparing rivaroxaban with placebo in adult ambulatory patients with various cancers who are initiating systemic cancer therapy and are at high risk of VTE (Khorana score ≥ 2). Patients with primary brain tumours or those at risk for bleeding are excluded. Approximately 700 patients will be randomized 1:1 to rivaroxaban 10 mg daily or placebo for up to 6 months if there is no evidence of VTE from compression ultrasonography (CU) during screening or from routine care imaging within 30 days prior to randomization. Mandatory CU will also be performed at weeks 8 and 16 (±7 days), and at study end (±3 days). The primary efficacy hypothesis is that anticoagulation with rivaroxaban reduces the composite of objectively confirmed symptomatic or asymptomatic, lower-extremity, proximal deep-vein thrombosis (DVT); symptomatic, upper-extremity DVT; symptomatic or incidental pulmonary embolism; and VTE-related death compared with placebo. The primary safety objective is to assess major bleeding events (Clinical trial information: NCT02555878)

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

    Get PDF
    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    The Transcriptome of Lutzomyia longipalpis (Diptera: Psychodidae) Male Reproductive Organs

    Get PDF
    BACKGROUND: It has been suggested that genes involved in the reproductive biology of insect disease vectors are potential targets for future alternative methods of control. Little is known about the molecular biology of reproduction in phlebotomine sand flies and there is no information available concerning genes that are expressed in male reproductive organs of Lutzomyia longipalpis, the main vector of American visceral leishmaniasis and a species complex. METHODS/PRINCIPAL FINDINGS: We generated 2678 high quality ESTs ("Expressed Sequence Tags") of L. longipalpis male reproductive organs that were grouped in 1391 non-redundant sequences (1136 singlets and 255 clusters). BLAST analysis revealed that only 57% of these sequences share similarity with a L. longipalpis female EST database. Although no more than 36% of the non-redundant sequences showed similarity to protein sequences deposited in databases, more than half of them presented the best-match hits with mosquito genes. Gene ontology analysis identified subsets of genes involved in biological processes such as protein biosynthesis and DNA replication, which are probably associated with spermatogenesis. A number of non-redundant sequences were also identified as putative male reproductive gland proteins (mRGPs), also known as male accessory gland protein genes (Acps). CONCLUSIONS: The transcriptome analysis of L. longipalpis male reproductive organs is one step further in the study of the molecular basis of the reproductive biology of this important species complex. It has allowed the identification of genes potentially involved in spermatogenesis as well as putative mRGPs sequences, which have been studied in many insect species because of their effects on female post-mating behavior and physiology and their potential role in sexual selection and speciation. These data open a number of new avenues for further research in the molecular and evolutionary reproductive biology of sand flies

    Preamplification techniques for real-time RT-PCR analyses of endomyocardial biopsies

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Due to the limited RNA amounts from endomyocardial biopsies (EMBs) and low expression levels of certain genes, gene expression analyses by conventional real-time RT-PCR are restrained in EMBs. We applied two preamplification techniques, the TaqMan<sup>® </sup>PreAmp Master Mix (T-PreAmp) and a multiplex preamplification following a sequence specific reverse transcription (SSRT-PreAmp).</p> <p>Results</p> <p>T-PreAmp encompassing 92 gene assays with 14 cycles resulted in a mean improvement of 7.24 ± 0.33 Ct values. The coefficients for inter- (1.89 ± 0.48%) and intra-assay variation (0.85 ± 0.45%) were low for all gene assays tested (<4%). The PreAmp uniformity values related to the reference gene CDKN1B for 91 of the investigated gene assays (except for CD56) were -0.38 ± 0.33, without significant differences between self-designed and ABI inventoried Taqman<sup>® </sup>gene assays. Only two of the tested Taqman<sup>® </sup>ABI inventoried gene assays (HPRT-ABI and CD56) did not maintain PreAmp uniformity levels between -1.5 and +1.5. In comparison, the SSRT-PreAmp tested on 8 self-designed gene assays yielded higher Ct improvement (9.76 ± 2.45), however was not as robust regarding the maintenance of PreAmp uniformity related to HPRT-CCM (-3.29 ± 2.40; p < 0.0001), and demonstrated comparable intra-assay CVs (1.47 ± 0.74), albeit higher inter-assay CVs (5.38 ± 2.06; p = 0.01). Comparing EMBs from each 10 patients with dilated cardiomyopathy (DCM) and inflammatory cardiomyopathy (DCMi), T-PreAmp real-time RT-PCR analyses revealed differential regulation regarding 27 (30%) of the investigated 90 genes related to both HPRT-CCM and CDKN1B. Ct values of HPRT and CDKN1B did not differ in equal RNA amounts from explanted DCM and donor hearts.</p> <p>Conclusion</p> <p>In comparison to the SSRT-PreAmp, T-PreAmp enables a relatively simple workflow, and results in a robust PreAmp of multiple target genes (at least 92 gene assays as tested here) by a mean Ct improvement around 7 cycles, and in a lower inter-assay variance in RNA derived from EMBs. Preliminary analyses comparing EMBs from DCM and DCMi patients, revealing differential regulation regarding 30% of the investigated genes, confirm that T-PreAmp is a suitable tool to perform gene expression analyses in EMBs, expanding gene expression investigations with the limited RNA/cDNA amounts derived from EMBs. CDKN1B, in addition to its function as a reference gene for the calculation of PreAmp uniformity, might serve as a suitable housekeeping gene for real-time RT-PCR analyses of myocardial tissues.</p
    corecore