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Search Results: 1 - 10 of 151768 matches for " F. Gonzalez-Salazar "
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Detection of Helicobacter pylori in dental plaque of mexican children by real-time PCR  [PDF]
J. A. Valdez-Gonzalez, P. C. Mares-Moreno, M. J. Kowolik, J. Vargas-Villlarreal, F. Gonzalez-Salazar, M. A. De la Garza-Ramos
Health (Health) , 2014, DOI: 10.4236/health.2014.64034
Abstract:

Dental plaque in adult patients is well identified as a reservoir for Helicobacter pylori. This question still remains unclear in children. The aim of this study is to identify the presence of this bacterium in dental plaque of Mexican pediatric patients, using Real Time Polymerase Chain Reaction (qPCR). Forty patients from 2 to 11 years without dyspeptic symptoms were enrolled. Samples were collected from the subgingival space of the lingual side of the lower molars and cultured in selective medium. Therefore, qPCR analysis was conducted. According to the results obtained in this study, it was found that 35% of the pediatric population who participated tested qPCR positive for the presence of H. pylori in dental plaque samples. No significant associations were detected among isolation rate by gender or age. We found that dental plaque may be a reservoir for H. pylori. However, more research is needed to establish the way of the infection of pediatric population.

Postnatally-transmitted HIV-1 Envelope variants have similar neutralization-sensitivity and function to that of nontransmitted breast milk variants
Fouda Genevieve G,Mahlokozera Tatenda,Salazar-Gonzalez Jesus F,Salazar Maria G
Retrovirology , 2013, DOI: 10.1186/1742-4690-10-3
Abstract: Background Breastfeeding is a leading cause of infant HIV-1 infection in the developing world, yet only a minority of infants exposed to HIV-1 via breastfeeding become infected. As a genetic bottleneck severely restricts the number of postnatally-transmitted variants, genetic or phenotypic properties of the virus Envelope (Env) could be important for the establishment of infant infection. We examined the efficiency of virologic functions required for initiation of infection in the gastrointestinal tract and the neutralization sensitivity of HIV-1 Env variants isolated from milk of three postnatally-transmitting mothers (n=13 viruses), five clinically-matched nontransmitting mothers (n=16 viruses), and seven postnatally-infected infants (n = 7 postnatally-transmitted/founder (T/F) viruses). Results There was no difference in the efficiency of epithelial cell interactions between Env virus variants from the breast milk of transmitting and nontransmitting mothers. Moreover, there was similar efficiency of DC-mediated trans-infection, CCR5-usage, target cell fusion, and infectivity between HIV-1 Env-pseudoviruses from nontransmitting mothers and postnatal T/F viruses. Milk Env-pseudoviruses were generally sensitive to neutralization by autologous maternal plasma and resistant to breast milk neutralization. Infant T/F Env-pseudoviruses were equally sensitive to neutralization by broadly-neutralizing monoclonal and polyclonal antibodies as compared to nontransmitted breast milk Env variants. Conclusion Postnatally-T/F Env variants do not appear to possess a superior ability to interact with and cross a mucosal barrier or an exceptional resistance to neutralization that define their capability to initiate infection across the infant gastrointestinal tract in the setting of preexisting maternal antibodies.
Multiplicacion in vitro de agave cocui trelease a traves de yemas axilares
Salazar,Efrain; Gonzalez,Pablo; Hernandez,Carlos;
Agronomía Tropical , 2009,
Abstract: the cocuy, agave cocui trelease is an important crop for the semiarid zones of the central-west part of venezuela. it is involved in a traditional production systems for liquor, soap, preserves, among others. it is the economical support of many families in lara state, venezuela. normally, the production was based in naturally occurring plants, so supply of plants is limited. in order to increase plant supply and improve the economical activity of these rural communities, asexual propagation systems have been implemented with slow growth rate and plant production not enough to satisfy the demand. a mass propagation system using axillary buds have been established. buds were placed on murashige and skoog (ms) medium supplemented with thyamine (1mg l-1), nicotinic acid (1mg l-1), pyridoxine hcl (1mg l-1), inositol (100mg l-1), ba (1mg l-1), ana (1mg l-1) sucrose (30 g l-1) and agar (5g l-1). forty explants were cultured in 10ml of culture medium, and were placed in the dark for 7 days. buds were placed under fluorescent light (16.95 w.m-2), at 28 ± 2 oc and a 16 hr photoperiod. shoots were observed 1 months after culture, an average of 6 shoots were observed for each cultured axillary bud. sprouting ratio was increased when temperatures was increased to 40 oc. complete plants were obtained by transferring shoots to medium with no hormones. transplant to soil (1:1:1 soil:sand:coconut sawdust) allowed plants to be acclimatized in 1 week. all plants have normal morphology. as a conclusion axillary bud in vitro culture can be referred as an efficient method to propagate a. cocui trelease
Inflammatory Genital Infections Mitigate a Severe Genetic Bottleneck in Heterosexual Transmission of Subtype A and C HIV-1
Richard E. Haaland,Paulina A. Hawkins,Jesus Salazar-Gonzalez,Amber Johnson,Amanda Tichacek,Etienne Karita,Olivier Manigart,Joseph Mulenga,Brandon F. Keele,George M. Shaw,Beatrice H. Hahn,Susan A. Allen,Cynthia A. Derdeyn,Eric Hunter
PLOS Pathogens , 2009, DOI: 10.1371/journal.ppat.1000274
Abstract: The HIV-1 epidemic in sub-Saharan Africa is driven largely by heterosexual transmission of non-subtype B viruses, of which subtypes C and A are predominant. Previous studies of subtype B and subtype C transmission pairs have suggested that a single variant from the chronically infected partner can establish infection in their newly infected partner. However, in subtype A infected individuals from a sex worker cohort and subtype B individuals from STD clinics, infection was frequently established by multiple variants. This study examined over 1750 single-genome amplified viral sequences derived from epidemiologically linked subtype C and subtype A transmission pairs very early after infection. In 90% (18/20) of the pairs, HIV-1 infection is initiated by a single viral variant that is derived from the quasispecies of the transmitting partner. In addition, the virus initiating infection in individuals who were infected by someone other than their spouse was characterized to determine if genital infections mitigated the severe genetic bottleneck observed in a majority of epidemiologically linked heterosexual HIV-1 transmission events. In nearly 50% (3/7) of individuals infected by someone other than their spouse, multiple genetic variants from a single individual established infection. A statistically significant association was observed between infection by multiple genetic variants and an inflammatory genital infection in the newly infected individual. Thus, in the vast majority of HIV-1 transmission events in cohabiting heterosexual couples, a single genetic variant establishes infection. Nevertheless, this severe genetic bottleneck can be mitigated by the presence of inflammatory genital infections in the at risk partner, suggesting that this restriction on genetic diversity is imposed in large part by the mucosal barrier.
A new approach to the Child-Langmuir law
Gabriel Gonzalez,F. J. Gonzalez
Physics , 2015,
Abstract: We analyze the motion of charged particles in a vacuum tube diode using a new set of variables. We obtain the space charge limited current for a charged particle moving non-relativistically in one dimension for the case of zero and non zero initial velocity. Our approach gives a new physical insight into the Child-Langmuir law and avoids the need of solving a nonlinear differential equation.
Analysis of Benzene Exposure Levels on Commuters Traveling within the Metropolitan Area of Costa Rica  [PDF]
Wendy Villalobos-Gonzalez, Germain Esquivel-Hernandez, Ricardo Sanchez-Murillo, José Leonardo Corrales-Salazar, Juan Valdes-Gonzalez
Open Journal of Air Pollution (OJAP) , 2015, DOI: 10.4236/ojap.2015.41005
Abstract: This study reports the benzene exposure levels of commuters traveling within the metropolitan area of Costa Rica using personal cars, buses, and urban trains. 47 in-vehicle samples were collected in the 2014 wet season under three different driving conditions: rush hour traffic, normal traffic and weekends. Samples were collected in Tedlar bags and analyzed using 75 μm carboxenpolydimethylsiloxane (CAR/PDMS) and gas chromatography with flame ionization detection (GC-FID). Additionally, duplicate samples were collected on adsorption tubes filled with Tenax TA and analyzed by thermal desorption (TD) and GC-FID. Results indicate that travelling in cars and buses under rush hour conditions exposes commuters to statistically equal average benzene concentration of 48.7 and 51.6 μg/m3, respectively. Average benzene levels in urban trains (33.0 μg/m3) were measured only during morning rush hours. Greater benzene levels in buses than personal cars concentrations may be attributable to the immersion of traffic-related emission within the bus cabins. Factors, such as the driving pattern, the number of vehicles on the route, the road infrastructure, and the prevalence of gasoline-fueled vehicles in Costa Rica, may increase ambient benzene concentrations. Benzene levels inside car cabins reported in this study are in the range of those reported in other urban areas; however, the corresponding concentrations inside buses and urban trains (rush hour only) are higher than previously published exposure levels.
High Multiplicity Infection by HIV-1 in Men Who Have Sex with Men
Hui Li equal contributor,Katharine J. Bar equal contributor,Shuyi Wang,Julie M. Decker,Yalu Chen,Chuanxi Sun,Jesus F. Salazar-Gonzalez,Maria G. Salazar,Gerald H. Learn,Charity J. Morgan,Joseph E. Schumacher,Peter Hraber,Elena E. Giorgi,Tanmoy Bhattacharya,Bette T. Korber,Alan S. Perelson,Joseph J. Eron,Myron S. Cohen,Charles B. Hicks,Barton F. Haynes,Martin Markowitz,Brandon F. Keele,Beatrice H. Hahn,George M. Shaw
PLOS Pathogens , 2010, DOI: 10.1371/journal.ppat.1000890
Abstract: Elucidating virus-host interactions responsible for HIV-1 transmission is important for advancing HIV-1 prevention strategies. To this end, single genome amplification (SGA) and sequencing of HIV-1 within the context of a model of random virus evolution has made possible for the first time an unambiguous identification of transmitted/founder viruses and a precise estimation of their numbers. Here, we applied this approach to HIV-1 env analyses in a cohort of acutely infected men who have sex with men (MSM) and found that a high proportion (10 of 28; 36%) had been productively infected by more than one virus. In subjects with multivariant transmission, the minimum number of transmitted viruses ranged from 2 to 10 with viral recombination leading to rapid and extensive genetic shuffling among virus lineages. A combined analysis of these results, together with recently published findings based on identical SGA methods in largely heterosexual (HSX) cohorts, revealed a significantly higher frequency of multivariant transmission in MSM than in HSX [19 of 50 subjects (38%) versus 34 of 175 subjects (19%); Fisher's exact p = 0.008]. To further evaluate the SGA strategy for identifying transmitted/founder viruses, we analyzed 239 overlapping 5′ and 3′ half genome or env-only sequences from plasma viral RNA (vRNA) and blood mononuclear cell DNA in an MSM subject who had a particularly well-documented virus exposure history 3–6 days before symptom onset and 14–17 days before peak plasma viremia (47,600,000 vRNA molecules/ml). All 239 sequences coalesced to a single transmitted/founder virus genome in a time frame consistent with the clinical history, and a molecular clone of this genome encoded replication competent virus in accord with model predictions. Higher multiplicity of HIV-1 infection in MSM compared with HSX is consistent with the demonstrably higher epidemiological risk of virus acquisition in MSM and could indicate a greater challenge for HIV-1 vaccines than previously recognized.
Susceptibilidad de genotipos de Solanum spp. al nematodo causante del nudo radical Meloidogyne spp. (chitwood)
Gelpud Chaves,Cristian; Mora Marcillo,Edwin; Salazar Gonzalez,Claudia;
Acta Agronómica , 2011,
Abstract: the green orange (solanum quitoense l.) crop has decreased in its productivity due to the pathogens attack such as the root knot nematode meloidogyne spp. in the nari?o department of colombia, pest incidences near to 79% and losses of 50% have been reported. in this study, 45 genotypes of solanum quitoense were collected in nari?o and putumayo departments. four wild genotypes (s. mammosum, s. hirtum, s. marginatum and s. umbellatum) were collected to look for nematode resistance sources. nine plants of each genotype two month old were inoculated with 10000 eggs of meloidogyne spp., leaving three plants as control by each material. the evaluated variables were: plant height, pest severity, pest incidence, fresh weight (stem and root) and meloidogyne spp. prevalent species. a genotype classification was made through a pest resistance scale and regression among severity and the rest of variables to determine the effect of meloidogyne spp. over the plant genotypes. the results showed 100% nematode incidence in all genotypes, resistant genotypes 2.04%, 34.7% moderately resistant, 42.8% moderately susceptible, 18.3% were susceptible, and 2.04% highly susceptible. the sqbr05 resistant genotype, was not affected by severity. on the other hand, the pest susceptible genotype sqbc04 showed significant reductions in stem and root fresh weight (r2 = 0.71 and 0.98), the wild genotype (s. mammosum) was highly susceptible, meloidogyne incognita showed 55.31% of presence. the sqbr05 genotype is promising to be evaluated in field.
LITOESTRATIGRAFíA Y PEDOESTRATIGRAFíA DE LOS DEPóSITOS RECIENTES EN EL ALTIPLANO DE SANTA ROSA DE OSOS (ASRO)
SALAZAR,SUSANA; GONZALEZ,LUIS HERNAN; ARIAS,LUIS ALBERTO;
Boletín de Ciencias de la Tierra , 2008,
Abstract: different deposits separated by two regional erosive discontinuities, as well as different kind of pedogenesis that superimposes these deposits, have been identified in the santa rosa de osos altiplano. in relation with the discontinuities, the deposits are from bottom to top: early deposits, middle age deposits and recent deposits. several largescale pedogenetic patterns allow the correlation and the elucidation of environmental conditions from which these patterns might have originated. these largescale pedogenetic patterns developed in the recent deposits, are part of the the paleoenvironmental record and can be used as guide horizons defined as pedostratigraphic mantles. such patterns were identified thorugh litostratigraphic and pedostratigraphic characterization of the material overlaying the discontinuity, which is a regional marker, associated with the "stone line" on other sectors of the antioquia department. thus, the litostratigraphy was carried out by means of field descriptions and mineralogical and granulometrical analysis. the pedostratigrahy was based on morphological profile description and physical and chemical analyses, allowing the identification of the profile genesis. this stratigraphic record allows elucidate environmental changes from cooler and dry phases to more humid and fresher with respect to recent climate.
Adenocarcinoma con diferenciacion apocrina de la glandula lagrimal
Lozano,M.; Gonzalez,F.;
Archivos de la Sociedad Espa?ola de Oftalmología , 2007, DOI: 10.4321/S0365-66912007000400008
Abstract: case report: a 74-year-old male presented with an orbital tumor located in the left lacrimal fossa. ocular examination showed hypotropia, exophthalmos and palpebral ptosis. discussion: removal of the tumor was performed by a lateral orbitotomy. the histopathologic study showed a tumor consistent with an adenocarcinoma of the lacrimal gland with apocrine differentiation.
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