40 research outputs found
The monoclonal antibody nBT062 conjugated to maytansinoids has potent and selective cytotoxicity against CD138 positive multiple myeloma cells _in vitro_ and _in vivo_
CD138 (Syndecan1) is highly expressed on multiple myeloma (MM) cells. In this study, we examined the anti-MM effect of murine/human chimeric CD138-specific monoclonal antibody (mAb) nBT062 conjugated with highly cytotoxic maytansinoid derivatives _in vitro_ and _in vivo_. These agents significantly inhibited growth of CD138-positive MM cell lines and primary tumor cells from MM patients, without cytotoxicity against peripheral blood mononuclear cells from healthy volunteers. In MM cells, they induced G2/M cell cycle arrest followed by apoptosis associated with cleavage of PARP and caspase-3, -8 and -9. Non-conjugated nBT062 completely blocked cytotoxicity induced by nBT062-maytansinoid conjugate, confirming that binding is required for inducing cytotoxicity. Moreover, nBT062-maytansinoid conjugates blocked adhesion of MM cells to bone marrow stromal cells (BMSCs). Co-culture of MM cells with BMSCs, which protects against dexamethasone-induced death, had no impact on the cytotoxicity of the immunoconjugates. Importantly, nBT062-SPDB-DM4 and nBT062-SPP-DM1 significantly inhibited MM tumor growth _in vivo_ in both human multiple myeloma xenograft mouse models and in SCID-human bone grafts (SCID-hu mouse model). These studies provide the preclinical framework supporting evaluation of nBT062-maytansinoid derivatives in clinical trials to improve patient outcome in MM
Optimizing Taq Polymerase Concentration for Improved Signal-to-Noise in the Broad Range Detection of Low Abundance Bacteria
BACKGROUND:PCR in principle can detect a single target molecule in a reaction mixture. Contaminating bacterial DNA in reagents creates a practical limit on the use of PCR to detect dilute bacterial DNA in environmental or public health samples. The most pernicious source of contamination is microbial DNA in DNA polymerase preparations. Importantly, all commercial Taq polymerase preparations inevitably contain contaminating microbial DNA. Removal of DNA from an enzyme preparation is problematical. METHODOLOGY/PRINCIPAL FINDINGS:This report demonstrates that the background of contaminating DNA detected by quantitative PCR with broad host range primers can be decreased greater than 10-fold through the simple expedient of Taq enzyme dilution, without altering detection of target microbes in samples. The general method is: For any thermostable polymerase used for high-sensitivity detection, do a dilution series of the polymerase crossed with a dilution series of DNA or bacteria that work well with the test primers. For further work use the concentration of polymerase that gave the least signal in its negative control (H(2)O) while also not changing the threshold cycle for dilutions of spiked DNA or bacteria compared to higher concentrations of Taq polymerase. CONCLUSIONS/SIGNIFICANCE:It is clear from the studies shown in this report that a straightforward procedure of optimizing the Taq polymerase concentration achieved "treatment-free" attenuation of interference by contaminating bacterial DNA in Taq polymerase preparations. This procedure should facilitate detection and quantification with broad host range primers of a small number of bona fide bacteria (as few as one) in a sample
An Efficient Strategy for Broad-Range Detection of Low Abundance Bacteria without DNA Decontamination of PCR Reagents
BACKGROUND: Bacterial DNA contamination in PCR reagents has been a long standing problem that hampers the adoption of broad-range PCR in clinical and applied microbiology, particularly in detection of low abundance bacteria. Although several DNA decontamination protocols have been reported, they all suffer from compromised PCR efficiency or detection limits. To date, no satisfactory solution has been found. METHODOLOGY/PRINCIPAL FINDINGS: We herein describe a method that solves this long standing problem by employing a broad-range primer extension-PCR (PE-PCR) strategy that obviates the need for DNA decontamination. In this method, we first devise a fusion probe having a 3'-end complementary to the template bacterial sequence and a 5'-end non-bacterial tag sequence. We then hybridize the probes to template DNA, carry out primer extension and remove the excess probes using an optimized enzyme mix of Klenow DNA polymerase and exonuclease I. This strategy allows the templates to be distinguished from the PCR reagent contaminants and selectively amplified by PCR. To prove the concept, we spiked the PCR reagents with Staphylococcus aureus genomic DNA and applied PE-PCR to amplify template bacterial DNA. The spiking DNA neither interfered with template DNA amplification nor caused false positive of the reaction. Broad-range PE-PCR amplification of the 16S rRNA gene was also validated and minute quantities of template DNA (10-100 fg) were detectable without false positives. When adapting to real-time and high-resolution melting (HRM) analytical platforms, the unique melting profiles for the PE-PCR product can be used as the molecular fingerprints to further identify individual bacterial species. CONCLUSIONS/SIGNIFICANCE: Broad-range PE-PCR is simple, efficient, and completely obviates the need to decontaminate PCR reagents. When coupling with real-time and HRM analyses, it offers a new avenue for bacterial species identification with a limited source of bacterial DNA, making it suitable for use in clinical and applied microbiology laboratories
Factores asociados a riesgo cardiometabólico en trabajadores de la Universidad Nacional Autónoma de Nicaragua (UNAN-Managua) del Recinto Universitario "Rubén DarÃo" en el perÃodo de Septiembre a Diciembre del año 2008
Se realizo unestudio descriptivo de corte tranversal sobre factores de riesgo cardiometabólico en trabajadores de la Universidad Nacional Autónoma de Niccaragua en el Recinto Universitario Rubén DarÃo durante el perÃodo de Septiembre a Diciembre de 2008, con el objetivo de conocer los factores asociados a riesgo cardiometabólico en los mismos y dar a conocer la scociación entre el tipo de riesgo coronario y los factores predictivos para desarrollar riesgo cardiovascular y poder intervenir de alguna manera en los mismo
Alfabetización digital que poseen los docentes de matemática en el ámbito de las tecnologÃas de información y comunicación-Caso: Docentes de educación media general del Municipio Escolar No 14 San José de Valencia, Estado Carabobo
La presente investigación consistió en describir la alfabetización digital que poseen los docentes de matemática de educación media general en el ámbito de TIC, adscritos a las instituciones educativas del Municipio Escolar No 14 San José de Valencia, estado Carabobo. El mismo se fundamentó en la teorÃa de Pere Marqués (2012), quien plantea tres dimensiones, las cuales son: Conocimiento Básico, Dominio Técnico Instrumental y Actitud hacia las TIC. Metodológicamente, se enmarcó en la modalidad de estudio descriptivo, con un diseño de campo no experimental y transeccional. Se contó con una población de (25) docentes y con una muestra de (20) docentes, a los cuales se les aplicó un instrumento tipo encuesta bajo los parámetros de la escala de Likert con una confiabilidad del 0,98 centésimas, considerada muy alta. De esta forma, los resultados arrojaron que la mayorÃa de los docentes poseen un conocimiento básico del computador Muy Alto. Asimismo, que en el dominio técnico instrumental los docentes son Altamente competentes y finalmente en cuanto a la Actitud en el uso de las TIC que los
docentes no poseen la actitud necesaria para aplicarlas. Por
ello se sugiere motivar a los docentes para que la actitud sea
favorable en referencia la alfabetización digital y asà lograr
complementar las estrategias para enriquecer el proceso de
enseñanza aprendizaje.
Palabras Clave: Alfabetización digital, TecnologÃa de Informa-
ción y Comunicación
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Prevalence and Genotypes of Cryptosporidium in Wildlife Populations Co-Located in a Protected Watershed in the Pacific Northwest, 2013 to 2016.
Between October 2013 and May 2016, 506 scat samples were collected from 22 species of wildlife located in a protected watershed of a major municipal water supply in the Pacific Northwest, USA. Overall prevalence of Cryptosporidium in the wildlife scat was 13.8% (70/506), with 15 species of wildlife found positive for Cryptosporidium. Prevalence of Cryptosporidium varied among species of wildlife, with higher prevalences observed in cougars (50.0%), mountain beavers (40.0%), and bobcats (33.3%), but none of these species are riparian-dependent. Genotyping of Cryptosporidium by sequencing PCR amplicons from the 18S rRNA gene were successful for seven species of wildlife, including bobcat, unknown predator, black-tailed deer, deer mouse, snowshoe hare, mountain beaver, and western spotted skunk. BLAST and phylogenetic analyses indicated that multiple species and genotypes of Cryptosporidium were present, with some isolates possibly co-circulating within and between wildlife populations in this protected watershed. Evidence of oocyst exchange between infected prey and their predators was also found. During the study period, several zoonotic Cryptosporidium species and genotypes that are uncommon in humans were detected in bobcat (99.58% identical to Cryptosporidium felis), unknown predator (100% identical to Cryptosporidium canis), snowshoe hare (100% identical to Cryptosporidium sp. skunk genotype), and mountain beaver (100% identical to Cryptosporidium ubiquitum). Novel sequences were also found in mountain beaver. To our knowledge, this is the first published report of a unique genotype or species of Cryptosporidium in mountain beaver (Aplodontia rufa)
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Prevalence and Genotypes of Cryptosporidium in Wildlife Populations Co-Located in a Protected Watershed in the Pacific Northwest, 2013 to 2016.
Between October 2013 and May 2016, 506 scat samples were collected from 22 species of wildlife located in a protected watershed of a major municipal water supply in the Pacific Northwest, USA. Overall prevalence of Cryptosporidium in the wildlife scat was 13.8% (70/506), with 15 species of wildlife found positive for Cryptosporidium. Prevalence of Cryptosporidium varied among species of wildlife, with higher prevalences observed in cougars (50.0%), mountain beavers (40.0%), and bobcats (33.3%), but none of these species are riparian-dependent. Genotyping of Cryptosporidium by sequencing PCR amplicons from the 18S rRNA gene were successful for seven species of wildlife, including bobcat, unknown predator, black-tailed deer, deer mouse, snowshoe hare, mountain beaver, and western spotted skunk. BLAST and phylogenetic analyses indicated that multiple species and genotypes of Cryptosporidium were present, with some isolates possibly co-circulating within and between wildlife populations in this protected watershed. Evidence of oocyst exchange between infected prey and their predators was also found. During the study period, several zoonotic Cryptosporidium species and genotypes that are uncommon in humans were detected in bobcat (99.58% identical to Cryptosporidium felis), unknown predator (100% identical to Cryptosporidium canis), snowshoe hare (100% identical to Cryptosporidium sp. skunk genotype), and mountain beaver (100% identical to Cryptosporidium ubiquitum). Novel sequences were also found in mountain beaver. To our knowledge, this is the first published report of a unique genotype or species of Cryptosporidium in mountain beaver (Aplodontia rufa)
A multiple evidence-based approach to Métis community-based monitoring: a case study from the South Athabasca Oil Sands Area, Alberta, Canada
This original research article provides a case study that describes how Métis indigenous knowledge was incorporated into the design of a community-based monitoring (CBM) program in the South Athabasca Oil Sands Area of Alberta, Canada. Athabasca Landing Métis Community (ALMC) members have traditional knowledge of local wildlife and climatic conditions in a region that has seen intense oil and gas-related industrial activity over the last 50 years. Informed by a multiple evidence-based approach to CBM, ALMC’s program design combined traditional hunting, fishing, trapping, and plant gathering activities with photomapping methods. By taking geo-referenced photos of their environmental observations, which they shared with other project participants during regular monitoring meetings, Métis knowledge holders connected changes in local conditions such as resource scarcity or species abundance to broader ecological processes including climate change. Further, the monitoring program had an innovative cultural camp component that brought elders, heads of family, and youth together to deliberately interact and pass on Indigenous and local knowledge. The information drawn from photomapping, cultural camps, and traditional knowledge shared during meetings was gathered into a database. The database serves as a repository of traditional knowledge and land use data that will support ALMC’s ongoing efforts to identify territory to promote self-governance and assert rights to lands and resources. We discuss how the ALMC’s adoption of a multiple evidence-based approach to monitoring asserts control over data collection methods, storage, and dissemination, supports local capacity for self-determination, and amplifies the voices of Métis harvesters in the resource management sector