810 research outputs found

    New synchronization method for <i>Plasmodium falciparum</i>

    Get PDF
    &lt;b&gt;Background&lt;/b&gt;: Plasmodium falciparum is usually asynchronous during in vitro culture. Although various synchronization methods are available, they are not able to narrow the range of ages of parasites. A newly developed method is described that allows synchronization of parasites to produce cultures with an age range as low as 30 minutes. &lt;b&gt;Methods&lt;/b&gt;: Trophozoites and schizonts are enriched using Plasmion. The enriched late stage parasites are immobilized as a monolayer onto plastic Petri dishes using concanavalin A. Uninfected erythrocytes are placed onto the monolayer for a limited time period, during which time schizonts on the monolayer rupture and the released merozoites invade the fresh erythrocytes. The overlay is then taken off into a culture flask, resulting in a highly synchronized population of parasites. &lt;b&gt;Results&lt;/b&gt;: Plasmion treatment results in a 10- to 13-fold enrichment of late stage parasites. The monolayer method results in highly synchronized cultures of parasites where invasion has occurred within a very limited time window, which can be as low as 30 minutes. The method is simple, requiring no specialized equipment and relatively cheap reagents. &lt;b&gt;Conclusions&lt;/b&gt;: The new method for parasite synchronization results in highly synchronized populations of parasites, which will be useful for studies of the parasite asexual cell cycle

    Evolution of protease inhibitor resistance in HIV-1-infected patients failing protease inhibitor monotherapy as second-line therapy in low-income countries: an observational analysis within the EARNEST randomised trial

    Get PDF
    BACKGROUND: Limited viral load (VL) testing in HIV-infected individuals on treatment in low-income countries often results in late detection of treatment failure. The impact of remaining on failing second-line, protease inhibitor (PI) containing regimens is unclear. METHODS: We retrospectively tested VL from 2,164 stored plasma samples from 386 patients randomised to receive PI-monotherapy (ritonavir-boosted lopinavir, after initial PI+raltegravir induction) in the EARNEST trial. Protease genotypic resistance testing was performed in samples with VL>1000 copies/ml. We assessed evolution of drug resistance mutations from virological failure (confirmed VL>1000 copies/ml) until discontinuation of PI-monotherapy and examined associations using Poisson and linear mixed-effects models. RESULTS: 118 patients had a median 68(IQR 48-88) weeks on PI-monotherapy post-failure. At failure, 21/107(20%) had intermediate/high resistance to lopinavir. 40-48 weeks post-failure, 49/72(68%) and 36/71(51%) had intermediate/high-level resistance to lopinavir and atazanavir. Most remained susceptible to darunavir (12/72[17%] intermediate, no high resistance). Common PI mutations were M46I, I54V, and V82A. On average, 1.7(95% CI 1.5,2.0) PI mutations developed per year; this increased after the first mutation developed, but decreased with subsequent mutations (p<0.0001). Modest VL changes were mainly driven by non-adherence (p=0.006) and PI mutation development. I47A was associated with a larger increase in log₁₀ VL(+0.53[+0.18,+0.87], p=0.003) than other PI mutations (+0.15[+0.07,+0.23] p<0.001; heterogeneity p=0.05). CONCLUSION: Most develop intermediate/high-level lopinavir resistance within one year when lopinavir/ritonavir is exposed to sustained VL replication without protection from other drugs. Even in this extreme situation, annual VL testing (current WHO recommendation) would identify failure when most would still benefit from switching to darunavir

    Transplantation for renal failure secondary to enteric hyperoxaluria: a case report

    Get PDF
    Enteric hyperoxaluria can lead to renal failure. There have only been a few reports of renal transplantation as treatment of endstage renal disease secondary to enteric hyperoxaluria and results have been mixed. This report describes a patient with Crohn's disease who developed chronic renal failure from enteric hyperoxaluria. He subsequently had a successful renal transplant without any post-operative oxalate related complications and has satisfactory renal function almost three years later. Aggressive pre-transplant hemodialysis was not done. The literature associated with renal transplantation for enteric hyperoxaluria is reviewed

    Normative data on the Bonn Risk Index for calcium oxalate crystallization in healthy children

    Get PDF
    Bonn Risk Index (BRI) is being used for the assessment of urinary calcium oxalate (CaOx) crystallization. There are no published data regarding BRI during growth. The objective of this study was to establish age- and sex-dependent BRI values in healthy children and adolescents. A total of 1,050 Caucasian subjects aged 3–18 years (525 males, 525 females) without a history of kidney stone disease were enrolled in the cross-sectional study. The study group was divided into 15 ranges according to age, each comprising 70 subjects. Urinary ionized calcium [Ca(2+)] was measured using a selective electrode while the onset of spontaneous crystallization was determined using a photometer and titrating with 40 mmol/L ammonium oxalate (Ox(2−)). The calculation of BRI value was based on the ratio of [Ca(2+)] to the required amount of ammonium oxalate added to 200 ml of urine to induce crystallization. The median BRI was 0.26 1/L and the values of the 5th and 95th percentiles were 0.06 1/L and 1.93 1/L, respectively. BRI correlated positively with body-area-related BRI (1/L × 1.73 m(2)) (R = 0.18; P < 0.05), whereas a negative correlation was found between BRI and body weight (1/L × kg) (R = −0.85; P < 0.05). Neither sex nor age differences were detected in BRI across studied children and adolescents. The values of Bonn Risk Index were constant during growth and there was a limited influence of age and sex on BRI in children over 3 years of age. The BRI may be valuable in the evaluation of pediatric patients at risk for kidney stones, particularly if the BRI from stone formers is demonstrated to be higher than in normal children

    Responses of marine benthic microalgae to elevated CO<inf>2</inf>

    Get PDF
    Increasing anthropogenic CO2 emissions to the atmosphere are causing a rise in pCO2 concentrations in the ocean surface and lowering pH. To predict the effects of these changes, we need to improve our understanding of the responses of marine primary producers since these drive biogeochemical cycles and profoundly affect the structure and function of benthic habitats. The effects of increasing CO2 levels on the colonisation of artificial substrata by microalgal assemblages (periphyton) were examined across a CO2 gradient off the volcanic island of Vulcano (NE Sicily). We show that periphyton communities altered significantly as CO2 concentrations increased. CO2 enrichment caused significant increases in chlorophyll a concentrations and in diatom abundance although we did not detect any changes in cyanobacteria. SEM analysis revealed major shifts in diatom assemblage composition as CO2 levels increased. The responses of benthic microalgae to rising anthropogenic CO2 emissions are likely to have significant ecological ramifications for coastal systems. © 2011 Springer-Verlag

    Promoting regional development through a collaborative project in entrepreneurship education: lessons from a regional experiment to develop entrepreneurial competences in children and youngsters

    Get PDF
    The chapter focuses on the reflection around the relationship between entrepreneurial empowerment and regional development, based on the assumptions, methodology and results of a self-sustained supramunicipal project in entrepreneurship education, promoted by a wide network of partners representing all the municipalities of Baixo Alentejo, Portugal, and coordinated by the Polytechnic Institute of Beja (IPBeja). The project Promoting Entrepreneurship Education at the Schools of Baixo Alentejo (PEEBA) was carried out in collaboration with Elementary Schools (1st to 2nd Ciclos) and kindergartens of Baixo Alentejo with the objective to nurture entrepreneurial competencies in children and youngsters aged 3–12 through practical and experiential entrepreneurship education. It provided them with entrepreneurial skills and attitudes that will increase their opportunities, by helping them face their lives with more initiative and confidence and/or be more proactive at work, or even start their own business in a near future, in the hope that this may eventually contribute to reduce the brain drain in Baixo Alentejo. With the motto the socioeconomic future of our region will be shaped by the students we are educating now, the PEEBA is innovative and unique, since it consists in a platform that brings together all the key stakeholders in the field of entrepreneurship education within all the municipalities of a NUTS, in this particular case Baixo Alentejo, who show an interest in working collaboratively for a common goal: to create a shared ecosystem favourable to entrepreneurship and entrepreneurial capacity

    Imaging Shock Waves in Diamond with Both High Temporal and Spatial Resolution at an XFEL

    Get PDF
    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions

    Coxiella burnetii Phagocytosis Is Regulated by GTPases of the Rho Family and the RhoA Effectors mDia1 and ROCK

    Get PDF
    The GTPases belonging to the Rho family control the actin cytoskeleton rearrangements needed for particle internalization during phagocytosis. ROCK and mDia1 are downstream effectors of RhoA, a GTPase involved in that process. Coxiella burnetii, the etiologic agent of Q fever, is internalized by the host´s cells in an actin-dependent manner. Nevertheless, the molecular mechanism involved in this process has been poorly characterized. This work analyzes the role of different GTPases of the Rho family and some downstream effectors in the internalization of C. burnetii by phagocytic and non-phagocytic cells. The internalization of C. burnetii into HeLa and RAW cells was significantly inhibited when the cells were treated with Clostridium difficile Toxin B which irreversibly inactivates members of the Rho family. In addition, the internalization was reduced in HeLa cells that overexpressed the dominant negative mutants of RhoA, Rac1 or Cdc42 or that were knocked down for the Rho GTPases. The pharmacological inhibition or the knocking down of ROCK diminished bacterium internalization. Moreover, C. burnetii was less efficiently internalized in HeLa cells overexpressing mDia1-N1, a dominant negative mutant of mDia1, while the overexpression of the constitutively active mutant mDia1-ΔN3 increased bacteria uptake. Interestingly, when HeLa and RAW cells were infected, RhoA, Rac1 and mDia1 were recruited to membrane cell fractions. Our results suggest that the GTPases of the Rho family play an important role in C. burnetii phagocytosis in both HeLa and RAW cells. Additionally, we present evidence that ROCK and mDia1, which are downstream effectors of RhoA, are involved in that processFil: Salinas Ojeda, Romina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Ortiz Flores, Rodolfo Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Distel, Jesús Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Aguilera, Milton Osmar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Beron, Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin
    corecore