833 research outputs found

    Tick saliva is a potent inhibitor of endothelial cell proliferation and angiogenesis

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    We report for the first time that saliva of the hard tick and Lyme disease vector,Ixodes scapularis,is a potent inhibitor of angiogenesis. Saliva (≤ 1:500 dilutions) or salivary gland (0.1–0.5 pairs/assay) dose-dependently inhibits microvascular endothelial cell (MVEC) proliferation. Inhibition was also detected with the saliva of the cattle tick Boophilus microplus but not with the salivary gland of Anopheles gambiae, An. stephensi, Lutzomyia longipalpis, Phlebotomus papatasi, Aedes aegypti, Culex quinquefasciatus, and Cimex lectularius. Inhibition of MVEC proliferation by I. scapularis saliva was accompanied by a change in cell shape (shrinkage of the cytoplasm with loss of cell-cell interactions) and apoptosis which was estimated by expression of phosphatidylserine using the Apopercentage dye, and by a typical pattern of chromatin margination, condensation, and fragmentation as revealed by nuclear staining with Hoechst 33258.The effect of saliva appears to be mediated by endothelial cell α5β1 integrin, because monoclonal antibodies against this but not αvβ3, αvβ5, α9β1, or α2β1 integrins remarkably block its effect. In addition, SDS/PAGE shows that saliva specifically degrades purified α5β1 but not αvβ5 or αvβ3 integrins. Incubation of saliva with EDTA and 1,10-phenanthroline, but not phenylmethylsulfonyl fluoride (PMSF), inhibits saliva-dependent degradation of purified α5β1 integrin, suggesting that a metalloprotease is responsible for the activity. Finally, saliva at ≤ 1:1,000 dilutions blocks sprouting formation from chick embryo aorta implanted in Matrigel, an in vitro model of angiogenesis. These findings introduce the concept that tick saliva is a negative modulator of angiogenesis-dependent wound healing and tissue repair, therefore allowing ticks to feed for days. Inhibition of angiogenesis was hitherto an unidentified biologic property of the saliva of any blood-sucking arthropod studied so far. Its presence in tick saliva may be regarded as an additional source of angiogenesis inhibitors with potential applications for the study of both vector and vascular biology

    Cloning of a salivary gland metalloprotease and characterization of gelatinase and fibrin(ogen)lytic activities in the saliva of the Lyme disease tick vector Ixodes scapularis

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    The full-length sequence of tick salivary gland cDNA coding for a protein similar to metalloproteases (MP) of the reprolysin family is reported. The Ixodes scapularis MP is a 488 amino acid (aa) protein containing pre- and pro-enzyme domains, the zinc-binding motif HExxHxxGxxH common to metalloproteases, and a cysteine-rich region. In addition, the predicted amino-terminal sequences of I. scapularis MPs were found by Edman degradation of PVDF-transferred SDS/PAGE-separated tick saliva proteins, indicating that these putative enzymes are secreted. Furthermore, saliva has a metal-dependent proteolytic activity towards gelatin, fibrin(ogen), and fibronectin, but not collagen or laminin. Accordingly, I. scapularis saliva has a rather specific metalloprotease similar to the hemorrhagic proteases of snake venoms. This is the first description of such activity in tick saliva and its role in tick feeding and Borrelia transmission is discussed

    Obesity increases eosinophil activity in asthmatic children and adolescents

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    A clear relationship between asthma and obesity has been reported, but the mechanisms remain unclear. The aim of this study was to evaluate the influence of obesity on eosinophil activity (chemotaxis and adhesion) in asthmatic children and adolescents compared with cells from healthy volunteers. Methods: Asthmatic obese (AO), asthmatic non-obese (ANO), non-asthmatic obese (NAO) and non-asthmatic non-obese (NANO) individuals were included in the present study. The chemotaxis of eosinophils after stimulation with eotaxin (300 ng/ml), platelet-activating factor (10 mu M; PAF) and RANTES (100 ng/ml) was performed using a microchemotaxis chamber. The eosinophil peroxidase activity was measured to determine the adhesion activity of eosinophils cultivated on fibronectin-coated plates. The serum leptin, adiponectin, TNF-alpha and IgE levels were quantified using ELISA assays. Results: The serum IgE levels and eosinophil counts were significantly higher in asthmatic (obese and non-obese) individuals compared with non-asthmatic individuals (obese and non-obese). Spontaneous eosinophil chemotaxis was greater in the AO group compared with either the ANO or NANO groups. The activation of eosinophils using eotaxin and PAF increased eosinophil chemotaxis in the AO group. RANTES treatment increased eosinophil chemotaxis in the NAO group compared with the NANO or ANO groups. The activation of eosinophils using eotaxin significantly increased eosinophil adhesion in the AO group compared with other groups. The serum leptin and TNF-alpha levels were higher in obese subjects (asthmatic and non-asthmatic), whereas the levels of adiponectin did not significantly differ among these groups. Conclusion: This study is the first to show increased eosinophilic activity (chemotaxis and adhesion) associated with high serum leptin and TNF-alpha levels in atopic asthmatic obese children and adolescents compared with non-obese healthy volunteers133

    The Gompertz-Pareto Income Distribution

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    This work analyzes the Gompertz-Pareto distribution (GPD) of personal income, formed by the combination of the Gompertz curve, representing the overwhelming majority of the economically less favorable part of the population of a country, and the Pareto power law, which describes its tiny richest part. Equations for the Lorenz curve, Gini coefficient and the percentage share of the Gompertzian part relative to the total income are all written in this distribution. We show that only three parameters, determined by linear data fitting, are required for its complete characterization. Consistency checks are carried out using income data of Brazil from 1981 to 2007 and they lead to the conclusion that the GPD is consistent and provides a coherent and simple analytical tool to describe personal income distribution data.Comment: 13 pages, 5 figures, LaTeX. Accepted for publication in "Physica A

    Purification of a serine protease and evidence for a protein C activator from the saliva of the tick, \u3cem\u3eIxodes scapularis\u3c/em\u3e

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    The saliva of ticks is critical to their survival as parasites and hematophagous animals. In this study, we have purified an enzyme with trypsin-like activity from the saliva of the tick vector of Lyme Disease, Ixodes scapularis. This enzyme, named as IXOSP (I. scapularis salivary serine protease), is a 29.9 kDa molecule with N-terminus FPxMVxLRIKxR. A BLAST search identified IXOSP as a secreted serine protease (AAY66740) with a conserved catalytic triad His, Asp, and Ser. In vitro studies demonstrated that IXOSP cleaves chromogenic substrates with arginine in the P1 position, by a mechanism inhibited by PMSF or aprotinin. Gene expression studies revealed that IXOSP is expressed at different tick developmental stages, including eggs, and unfed or fed adult tick salivary glands, but not in nymphs or in the midgut. While the physiological substrate for IXOSP remains to be identified, we demonstrated that I. scapularis saliva activate protein C (PC) resulting in the production of activated PC, a potent anticoagulant that also regulates a myriad of inflammatory responses through protease activated receptors. In contrast, the salivary glands of Anopheles gambiae, Anopheles stephensi, Anopheles albimanus, Aedes aegypti, Lutzomyia longipalpis, and Phlebotomus ariasi did not activate protein C. These discoveries are discussed in the context of blood coagulation, inflammation and vector–host interactions

    Impacts of the SARS-CoV-2 pandemic on the global demand for exotic pets: An expert elicitation approach

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    The SARS-CoV-2 pandemic has caused immense social and economic costs worldwide. Most experts endorse the view that the virus has a zoonotic origin with the final spillover being associated with wildlife trade. Besides human consumption, wild animals are also extensively traded as pets. Information on zoonotic diseases has been reported to reduce consumer demand for exotic pets. We conducted a global survey and collected 162 responses from international experts on exotic pet trade (traders, academics, NGOs, enforcement entities) to understand how the legal and illegal trade of exotic pets is expected to be affected by the ongoing coronavirus pandemic. Our results suggest that legal purchase of exotic pets is perceived as decreasing during the first pandemic wave due to: lower availability of animals for trade, suppliers’ inability to reach consumers and social distancing measures. The general perception is that in the future (i.e., next five years), both demand and supply of legally traded exotic pets are expected to either remain unchanged or decrease only temporarily. The consumer demand for illegal exotic pets is also expected to remain unchanged following the outbreak. The top two challenges reported by respondents, when considering the consequences of the pandemic for the exotic pet trade, are inadequate enforcement of national regulations and increased illegal trade. Our results suggest that the negative consequences of a zoonotic outbreak may not dissuade consumers of exotic pets. Worldwide, the transit/storing conditions and lack of health screenings of traded live animals are conducive to spreading diseases. Consumer demand is a key driver of trade, and enforcement of trade regulations will remain challenging, unless factors driving consumer demand are adequately incorporated in problem-solving frameworks. We emphasize the complexity of trade dynamics and the need to go beyond bans on wildlife trade. Stronger law enforcement, implemented along with initiatives dissuading consumption of wild exotic pets, are essential to sustainably satisfy the market demandinfo:eu-repo/semantics/publishedVersio

    Anti rickettsia-antibody for spotted fever group in horses and dogs in the North of Paraná Stated, Brazil

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    The Brazilian Spotted Fever (BSF) is a zoonosis that can be fatal if not trteated. As there are few studies of the BSF in the Paraná State, the occurrence of BSF was serologically investigated in dogs and horses by indirect immunofluorescence assay (IFA), in the North of that State, in animals that are regarded as sentinels for BSF. A total of 241 samples of sera of equine, four of asinine, and 29 of dogs were collected in nine farms of three municipalities in the North of Paraná: Arapongas, Douradina, and Umuarama. From fifteen samples of equine serum with positive titres for RIFI, eight (53.3 %) had titre of 64 against R. rickettsii, two (13.3 %) 128 against R. rickettsii, and five (33.3 %) were reactants for R. parkeri and R. rickettsii, with titres ranging from 64 to 2048, and 128 to 1024, respectively. The results showed that domestic animals, sentinels for BSF, are under low exposition to ticks infected with spotted fever group Rickettsia, indicating low risk of human infection by these agents in the studied area

    The Role of Exercise on L-Arginine Nitric Oxide Pathway in Chronic Heart Failure

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    Chronic heart failure (CHF) is a pathological state with high morbidity and mortality and the full understanding of its genesis remain to be elucidated. In this syndrome, a cascade of neurohormonal and hemodynamic mechanisms, as well as inflammatory mediators, are activated to improve the impaired cardiac function. Clinical and experimental observations have shown that CHF is associated with a generalized disturbance in endothelium-dependent vasodilation, which may contribute to the progression of ventricular and vascular remodelling in this syndrome. There is also accumulating evidence that disturbances in nitric oxide (NO) availability is involved in the development of heart failure at the systemic and cardiac levels. NO is a ubiquitous signalling molecule which causes potent vasodilation, inhibits platelet activation and regulates the contractile properties of cardiac myocytes. It is generated from the amino acid L-arginine via constitutive and inducible isoforms of the enzyme NO synthase (NOS). There is evidence that exercise, a nonpharmacological tool, improves symptoms, fitness (VO2peak), quality of life and NO bioavailability in CHF population. This review examines different aspects of the L-arginine-NO pathway and inflammation in the physiopathology of CHF and highlights the important beneficial effects of exercise in this disease

    Acute and Second Meal Effects of Peanuts on Glycemic Response and Appetite in Obese Women with High Type 2 Diabetes Risk: A Randomized Crossover Clinical Trial.

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    Nut consumption is associated with a reduced risk of type 2 diabetes mellitus (T2DM). The aim of the present study was to assess the effects of adding peanuts (whole or peanut butter) on first (0–240 min)- and second (240–490 min)-meal glucose metabolism and selected gut satiety hormone responses, appetite ratings and food intake in obese women with high T2DM risk. A group of fifteen women participated in a randomised cross-over clinical trial in which 42·5 g of whole peanuts without skins (WP), peanut butter (PB) or no peanuts (control) were added to a 75 g available carbohydrate-matched breakfast meal. Postprandial concentrations (0–490 min) of glucose, insulin, NEFA, glucagon-like peptide-1 (GLP-1), peptide YY (PYY), cholecystokinin (CCK), appetitive sensations and food intake were assessed after breakfast treatments and a standard lunch. Postprandial NEFA incremental AUC (IAUC) (0–240 min) and glucose IAUC (240–490 min) responses were lower for the PB breakfast compared with the control breakfast. Insulin concentrations were higher at 120 and 370 min after the PB consumption than after the control consumption. Desire-to-eat ratings were lower, while PYY, GLP-1 and CCK concentrations were higher after the PB intake compared with the control intake. WP led to similar but non-significant effects. The addition of PB to breakfast moderated postprandial glucose and NEFA concentrations, enhanced gut satiety hormone secretion and reduced the desire to eat. The greater bioaccessibility of the lipid component in PB is probably responsible for the observed incremental post-ingestive responses between the nut forms. Inclusion of PB, and probably WP, to breakfast may help to moderate glucose concentrations and appetite in obese women

    New Records Of Bird Species From Ilha Grande, State Of Rio De Janeiro, Southeastern Brazil

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We add 32 new records of species to the existing checklist of birds of the coastal island of Ilha Grande, state of Rio de Janeiro, Brazil. Notably, seven of these species are endemic to the Atlantic Forest. Sporophila falcirostris is globally Vulnerable and Haematopus palliatus is Near Threatened in Brazil. We also report the second record of Agelaioides badius from Rio de Janeiro state. We also compare our species list with lists of birds of Ilhabela and Anchieta islands. While some of the newly recorded species are probably non-resident to Ilha Grande or represent range expansions, most species occur in Rio de Janeiro throughout the year. Thus, our records may be a consequence of the surveying new sites on the island but also recent colonization. Our study increases the number of bird species known to occur on Ilha Grande from 222 to 254, which is one-third of the species reported from Rio de Janeiro state. We recorded 13 species threatened by extinction at regional, national or global levels. © 2016 Check List and Authors.126CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico305798/2014-6, FAPERJ, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de JaneiroE-26/102.837868/2012, FAPERJ, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de JaneiroUERJ, Universidade do Estado do Rio de JaneiroConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
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