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Search Results: 1 - 10 of 439387 matches for " Juárez M Patricia "
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Epicuticular lipids induce aggregation in Chagas disease vectors
Alicia Figueiras, Juan R Girotti, Sergio J Mijailovsky, M Patricia Juárez
Parasites & Vectors , 2009, DOI: 10.1186/1756-3305-2-8
Abstract: We analyzed the response of T. infestans fifth instar nymphs after exposure to different amounts either of total epicuticular lipid extracts or individual lipid fractions. Assays were performed in a circular arena, employing a binary choice test with filter papers acting as aggregation attractive sites; papers were either impregnated with a hexane-extract of the total lipids, or lipid fraction; or with the solvent. Insects were significantly aggregated around papers impregnated with the epicuticular lipid extracts. Among the lipid fractions separately tested, only the free fatty acid fraction promoted significant bug aggregation. We also investigated the response to different amounts of selected fatty acid components of this fraction; receptiveness varied with the fatty acid chain length. No response was elicited by hexadecanoic acid (C16:0), the major fatty acid component. Octadecanoic acid (C18:0) showed a significant assembling effect in the concentration range tested (0.1 to 2 insect equivalents). The very long chain hexacosanoic acid (C26:0) was significantly attractant at low doses (≤ 1 equivalent), although a repellent effect was observed at higher doses.The detection of contact aggregation pheromones has practical application in Chagas disease vector control. These data may be used to help design new tools against triatomine bugs.The lipid layer on the insect cuticle comprises a complex mixture of hydrocarbons, free and esterified fatty acids and fatty alcohols, and smaller amounts of other oxygenated components [1,2]. Their role protecting insects from water loss and hence preventing lethal desiccation is widely recognized [3-5]. They are also the first barrier against chemical or biological contact insecticides [6,7]. Growing evidence has been gathered for more than 30 years on the role of hydrocarbons in chemical communication in many insect species [8]. However, relatively few reports are available on the participation of oxygenated cuticular lipid compo
Cuticular hydrocarbons of Chagas disease vectors in Mexico
Juárez, M Patricia;Carlson, David A;Salazar Schettino, Paz María;Mijailovsky, Sergio;Rojas, Gloria;
Memórias do Instituto Oswaldo Cruz , 2002, DOI: 10.1590/S0074-02762002000600012
Abstract: capillary gas-liquid chromatography was used to analyse the cuticular hydrocarbons of three triatomine species, triatoma dimidiata, t. barberi and dipetalogaster maxima, domestic vectors of chagas disease in mexico. mixtures of saturated hydrocarbons of straight and methyl-branched chains were characteristic of the three species, but quantitatively different. major methylbranched components mostly corresponded to different saturated isomers of monomethyl, dimethyl and trimethyl branched hydrocarbons ranging from 29 to 39 carbon backbones. sex-dependant, quantitative differences in certain hydrocarbons were apparent in t. dimidiata.
Cuticular hydrocarbons of Chagas disease vectors in Mexico
Juárez M Patricia,Carlson David A,Salazar Schettino Paz María,Mijailovsky Sergio
Memórias do Instituto Oswaldo Cruz , 2002,
Abstract: Capillary gas-liquid chromatography was used to analyse the cuticular hydrocarbons of three triatomine species, Triatoma dimidiata, T. barberi and Dipetalogaster maxima, domestic vectors of Chagas disease in Mexico. Mixtures of saturated hydrocarbons of straight and methyl-branched chains were characteristic of the three species, but quantitatively different. Major methylbranched components mostly corresponded to different saturated isomers of monomethyl, dimethyl and trimethyl branched hydrocarbons ranging from 29 to 39 carbon backbones. Sex-dependant, quantitative differences in certain hydrocarbons were apparent in T. dimidiata.
Catheter-related septic thrombophlebitis of the great central veins successfully treated with low-dose streptokinase thrombolysis and antimicrobials
Patricia Volkow, Patricia Cornejo-Juárez, Ana Arizpe-Bravo, Jorge García-Méndez, Enrique Baltazares-Lipp, Rogelio Pérez-Padilla
Thrombosis Journal , 2005, DOI: 10.1186/1477-9560-3-11
Abstract: We describe three patients with cancer and septic thrombophlebitis of central veins caused by Staphylococcus aureus treated with catheter removal, thrombolysis, and intravenous (IV) antibiotics. In our reported cases, an initial bolus of 250,000 international units (IU) of streptokinase administered during the first h followed by an infusion of 20,000–40,000 IU/h for 24–36 h through a proximal peripheral vein was sufficient to dissolve the thrombus. After thrombolyisis and parenteral antibiotic for 4–6 weeks the septic thrombosis due to Staphylococcus aureus solved in all cases. No surgical procedure was needed, and potential placement of a catheter in the same vein was permitted.Thrombolysis with streptokinase solved symptoms, cured infection, prevented embolus, and in all cases achieved complete thrombus lysis, avoiding permanent central-vein occlusion.Septic thrombophlebitis is an iatrogenic life-threatening disease associated with use of central venous devices and intravenous (IV) therapy. [1-3] Sole use of antimicrobials is rarely effective for controlling infection, requiring removal of the device and anticoagulation but in some cases a more aggressive approach such as resection of the affected vein [2,4-7] or trombectomy is needed [8]. Vein resection or surgical thrombectomy is time-consuming in large central venous lines, has a high rate of complications, can delay administration of chemotherapy, and therefore delay or impede tumor control. Experience with thrombolysis has been published for catheter-related thrombosis [9-13] but for septic thrombosis, this experience is scarce. [14,15] Herein, we describe three women with cancer and septic thrombophlebitis due to Staphylococcus aureus methicillin sensitive, who failed to resolve with catheter removal, parenteral antibiotics, and anticoagulation therapy and who were successfully treated with low-dose streptokinase fibrinolysis. All patients were receiving chemotherapy through non-tunneled polyurethane, singl
Control of Pyrethroid-Resistant Chagas Disease Vectors with Entomopathogenic Fungi
Nicolás Pedrini,Sergio J. Mijailovsky,Juan R. Girotti,Raúl Stariolo,Rubén M. Cardozo,Alberto Gentile,M. Patricia Juárez
PLOS Neglected Tropical Diseases , 2009, DOI: 10.1371/journal.pntd.0000434
Abstract: Background Triatoma infestans-mediated transmission of Tripanosoma cruzi, the causative agent of Chagas disease, remains as a major health issue in southern South America. Key factors of T. infestans prevalence in specific areas of the geographic Gran Chaco region—which extends through northern Argentina, Bolivia, and Paraguay—are both recurrent reinfestations after insecticide spraying and emerging pyrethroid-resistance over the past ten years. Among alternative control tools, the pathogenicity of entomopathogenic fungi against triatomines is already known; furthermore, these fungi have the ability to fully degrade hydrocarbons from T. infestans cuticle and to utilize them as fuel and for incorporation into cellular components. Methodology and Findings Here we provide evidence of resistance-related cuticle differences; capillary gas chromatography coupled to mass spectrometry analyses revealed that pyrethroid-resistant bugs have significantly larger amounts of surface hydrocarbons, peaking 56.2±6.4% higher than susceptible specimens. Also, a thicker cuticle was detected by scanning electron microscopy (32.1±5.9 μm and 17.8±5.4 μm for pyrethroid-resistant and pyrethroid-susceptible, respectively). In laboratory bioassays, we showed that the virulence of the entomopathogenic fungi Beauveria bassiana against T. infestans was significantly enhanced after fungal adaptation to grow on a medium containing insect-like hydrocarbons as the carbon source, regardless of bug susceptibility to pyrethroids. We designed an attraction-infection trap based on manipulating T. infestans behavior in order to facilitate close contact with B. bassiana. Field assays performed in rural village houses infested with pyrethroid-resistant insects showed 52.4% bug mortality. Using available mathematical models, we predicted that further fungal applications could eventually halt infection transmission. Conclusions This low cost, low tech, ecologically friendly methodology could help in controlling the spread of pyrethroid-resistant bugs.
Patricia,Landeros; Noa,M; López,Yolanda; González,Delia G; Noa,Elizabeth; Real,M; Juárez,C; Medina,Miriam S;
Revista de Salud Animal , 2012,
Abstract: aflatoxin m1 (afm1) is a milk hygiene quality indicator established in mexico. aflatoxin m1 is a metabolite of aflatoxin b1 (afb1), becoming from contaminated feed. the thermal treatments usually applied to raw milk did not reduce the concentrations on afm1 in milk. the aim of the present work was to conduct a screening of afm1 i raw (n=50) collected from raw milk collecting facilities and 7 pasteurized milk brand (n=84) samples. all the samples tested were both produced in jalisco state and commercialized in guadalajara, mexico. the analyses were performed using the competitive direct elisa kit agraquant? aflatoxin m1 (romer labs). statistical analysis was performed using a one-way anova by sigma stat 3.0 program. afm1 was found in 100% of the tested samples, ranging from < 0.005 to 0.100 μg/l in raw milk, and from < 0.005 to 0.637 μg in pasteurized milk. a total 18.6% (25/134) samples showed levels above maximum residue limit (mrl) established by the european community (0.05 μg/kg), 0.7% (1/134) for raw and 17.9% (24/134) for pasteurized milk. only 0.7% (1/134) of the tested samples exceeded this mrl established in mexico by nom-243-ssa1-2010 which is 0.5 μg/l afm1. statistical differences were found (p<0.05) between sampling months; the highest level was detected in december, while no differences were detected among milk collecting facilities and either among pasteurized milk brands.
Biological Control of the Chagas Disease Vector Triatoma infestans with the Entomopathogenic Fungus Beauveria bassiana Combined with an Aggregation Cue: Field, Laboratory and Mathematical Modeling Assessment
Lucas Forlani?,Nicolás Pedrini?,Juan R. Girotti?,Sergio J. Mijailovsky?,Rubén M. Cardozo?,Alberto G. Gentile?,Carlos M. Hernández-Suárez,Jorge E. Rabinovich?,M. Patricia Juárez
PLOS Neglected Tropical Diseases , 2015, DOI: 10.1371/journal.pntd.0003778
Abstract: Background Current Chagas disease vector control strategies, based on chemical insecticide spraying, are growingly threatened by the emergence of pyrethroid-resistant Triatoma infestans populations in the Gran Chaco region of South America. Methodology and findings We have already shown that the entomopathogenic fungus Beauveria bassiana has the ability to breach the insect cuticle and is effective both against pyrethroid-susceptible and pyrethroid-resistant T. infestans, in laboratory as well as field assays. It is also known that T. infestans cuticle lipids play a major role as contact aggregation pheromones. We estimated the effectiveness of pheromone-based infection boxes containing B. bassiana spores to kill indoor bugs, and its effect on the vector population dynamics. Laboratory assays were performed to estimate the effect of fungal infection on female reproductive parameters. The effect of insect exuviae as an aggregation signal in the performance of the infection boxes was estimated both in the laboratory and in the field. We developed a stage-specific matrix model of T. infestans to describe the fungal infection effects on insect population dynamics, and to analyze the performance of the biopesticide device in vector biological control. Conclusions The pheromone-containing infective box is a promising new tool against indoor populations of this Chagas disease vector, with the number of boxes per house being the main driver of the reduction of the total domestic bug population. This ecologically safe approach is the first proven alternative to chemical insecticides in the control of T. infestans. The advantageous reduction in vector population by delayed-action fungal biopesticides in a contained environment is here shown supported by mathematical modeling.
Protective effects of Spirulina maxima on hyperlipidemia and oxidative-stress induced by lead acetate in the liver and kidney
Johny C Ponce-Canchihuamán, Oscar Pérez-Méndez, Rolando Hernández-Mu?oz, Patricia V Torres-Durán, Marco A Juárez-Oropeza
Lipids in Health and Disease , 2010, DOI: 10.1186/1476-511x-9-35
Abstract: The results showed that Spirulina maxima prevented the lead acetate-induced significant changes on plasma and liver lipid levels and on the antioxidant status of the liver and kidney. On the other hand, Spirulina maxima succeeded to improve the biochemical parameters of the liver and kidney towards the normal values of the Control group.It was concluded that Spirulina maxima has protective effects on lead acetate-induced damage, and that the effects are associated with the antioxidant effect of Spirulina.The lead is a xenobiotic, persistent toxic [1,2], as other xenobiotics induces to different health risks since the fetal stage until senescence. On the other hand, although lead is one of the most useful metals, it is also one of the most toxic ones [3]. Also, both occupational and environmental exposures remain a serious problem in many developing and industrializing countries [4].Several reports have indicated that lead can cause neurological, hematological, gastrointestinal, reproductive, circulatory, and immunological pathologies, all of them related to the dose and the amount of time of lead exposure [5-8]. Also, the health risks occasioned by exposure to lead are considered public health problems at a world level.The liver plays a major role in lead's metabolism, and it is in special risk due to the oxidative action of this xenobiotic; given the unquestionable evidence that lead-induced lipid peroxidation of cellular membranes, plays a crucial role in the mechanisms of hepatotoxic action of these xenobiotics [9]. On the other hand, lead is known to also affect the kidney, which is another important target [10]. Lead produces oxidative damage in the kidney as evidenced by enhancing lipid peroxidation (LIP) [11,12].In vivo and in vitro studies suggest that lipid metabolism is altered both in acute and chronic exposure to lead [13]. Lead inhibits antioxidant enzyme activity, such as superoxide dismutase and catalase, and also decreases the level of glutathione, i
Damping-Antidamping Effect on Comets Motion  [PDF]
G. V. López, E. M. Juárez
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.412204

We make an observation about Galilean transformation on a 1-D mass variable system which leads us to the right way to deal with mass variable systems. Then using this observation, we study two-body gravitational problem where the mass of one of the bodies varies and suffers a damping-antidamping effect due to star wind during its motion. For this system, a constant of motion, a Lagrangian and a Hamiltonian are given for the radial motion, and the period of the body is studied using the constant of motion of the system. Our theoretical results are applied to Halley’s Comet.

Relationship between scripts interruptions and consumers affective judgements in users of a university cafeteria
Fernando Juárez,Alba Patricia Roa,ángela María Guerra
International Journal of Psychological Research , 2008,
Abstract: This study analyzes the relationship among various types of script interruptions and affective judgments of satisfaction and quality for users of a university cafeteria. It replicates the study carried out in Spain by Falces, Sierra, Bri ol and Horcajo (2002). A questionnaire on satisfaction and quality service, developed by Falces, et al. (2002), was used. In terms of satisfaction, unsolved or unsuccessfully solved errors and obstacles leaded to morenegative judgments than interruptions with a positive outcome and distractions were located in an intermediate position. Errors and obstacles both with a positive or negative solution differed among them; distractions differed from all other categories. This finding is different from the results obtained in the Spanish sample where nodifference was found between obstacles and errors with a negative outcome and where distractions did not differ from other categories. Concerning quality service, distractions received the lowest score. The most significant differences were found between distractions and obstacles and between obstacles and errors. This finding alsodiffers from the Spanish results where such categories show a similar pattern in terms of satisfaction.
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