Isothermal Amplification Using a Chemical Heating Device for Point-of-Care Detection of HIV-1

Background: To date, the use of traditional nucleic acid amplification tests (NAAT) for detection of HIV-1 DNA or RNA has been restricted to laboratory settings due to time, equipment, and technical expertise requirements. The availability of a rapid NAAT with applicability for resource-limited or point-of-care (POC) settings would fill a great need in HIV diagnostics, allowing for timely diagnosis or confirmation of infection status, as well as facilitating the diagnosis of acute infection, screening and evaluation of infants born to HIV-infected mothers. Isothermal amplification methods, such as reversetranscription, loop-mediated isothermal amplification (RT-LAMP), exhibit characteristics that are ideal for POC settings, since they are typically quicker, easier to perform, and allow for integration into low-tech, portable heating devices. Methodology/Significant Findings: In this study, we evaluated the HIV-1 RT-LAMP assay using portable, non-instrumented nucleic acid amplification (NINA) heating devices that generate heat from the exothermic reaction of calcium oxide and water. The NINA heating devices exhibited stable temperatures throughout the amplification reaction and consistent amplification results between three separate devices and a thermalcycler. The performance of the NINA heaters was validated using whole blood specimens from HIV-1 infected patients. Conclusion: The RT-LAMP isothermal amplification method used in conjunction with a chemical heating device provides

El uso de la tecnología en el aula de matemáticas: diferencias de género desde la perspectiva de los docentes

Desde 1997 la Secretaría de Educación Pública en México ha promovido el proyecto nacional EMAT (Enseñanza de las Matemáticas con Tecnología) usando computadoras y calculadoras TI-92 para apoyar la enseñanza de las matemáticas en la escuela secundaria (alumnos entre 12 y 15 años de edad). En el marco de este proyecto hemos investigado como se ve afectado, según los profesores, el comportamiento de los estudiantes cuando se usa la tecnología para apoyar la enseñanza de las matemáticas. En particular se analiza si las respuestas de los profesores ponen en evidencia posibles diferencias de género. Veinticuatro docentes expresaron sus puntos de vista acerca de los cambios apreciados en 1.113 estudiantes en relación a: participación; capacidad para analizar un problema e interpretar las hojas de trabajo; iniciativa; solicitud de ayuda; dedicación; defensa de sus ideas; creatividad; preferencia por trabajo en equipo o individual. Los resultados muestran que, desde la perspectiva de los docentes, el uso de la tecnología en la clase de matemáticas modifica la mayoría de estos aspectos y estos cambios son distintos en varones y en mujeres. Además, los datos sugieren que los cambios de conducta conllevan una mayor equidad de género.</jats:p

HIV-1 subtypes and recombinants in Northern Tanzania: distribution of viral quasispecies.

This study analyzed the distribution and prevalence of HIV-1 subtypes, multiplicity of HIV-1 infection, and frequency of inter-subtype recombination among HIV-1-infected female bar and hotel workers in Moshi, Kilimanjaro Region, Tanzania, from 2004 to 2007. The HIV-1 viral sequences spanning the V1-C5 region of HIV-1 env gp120 were analyzed from 50 subjects by single genome amplification and sequencing (SGA/S) technique. A total of 1740 sequences were amplified and sequenced from the HIV-1 proviral DNA template. The median env sequences analyzed per subject per two time points was 38 (IQR 28-50) over one year of HIV infection. In a subset of 14 subjects, a total of 239 sequences were obtained from HIV-1 RNA template at the baseline visit. The most prevalent HIV-1 subtypes were A1 (56%) and C (30%), while HIV-1 subtype D and inter-subtype recombinant viruses were found in 6% and 8% of subjects respectively. Transmission of multiple HIV-1 variants was evident in 27% of the subjects infected with pure HIV-1 subtypes A1, C, or D. The HIV-1 inter-subtype recombinants were found in 8% including HIV-1 C/A, D/A, and complex mosaic recombinants. Multiple viral variants were found in two subjects infected with inter-subtype recombinants. One subject harbored quasispecies of both pure HIV-1 A1 and C/A recombinant. The other subject was infected with two complex mosaic inter-subtype recombinant variants belonging to subtype D. HIV-1 multiple infections and ongoing recombination contribute significantly to the genetic diversity of circulating HIV-1 in Tanzania and have important implications for vaccine design and the development of therapeutic strategies

Candidate HIV-1 Tat vaccine development: from basic science to clinical trials.

Abstract not availabl

Genetic and phylogenetic analyses of HIV-1 corroborate the transmission link hypothesis

Background: Phylogenetic and genetic analyses have proven a valuable tool to infer epidemiological links between human immunodeficiency virus type-1 (HIV-1) isolates. These methods were applied in the present report for studying the genetic relatedness of the viral strains involved in two episodes of suspected HIV-1 transmission. Objectives: Provide any evidence that may help establish or refute the transmission link. Study design: In the first case, a leukemic patient became HIV-1 positive following the transfusion of platelets from a donor who was subsequently found to have tested false HIV-seronegative and to be sexual partner to an infected woman. In the second, a wife claimed to have acquired the infection from her husband who had concealed his infected status. Results and conclusions: The viral pairs detected in each of the suspected transmission cases exhibited common amino acid signatures and low genetic distances and segregated together in phylogenetic trees, thus showing a level of genetic relatedness similar to reference pairs known with certainty to be epidemiologically linked. These findings corroborated the existence of a direct transmission link in both the episodes with a high level of confidence. (C) 2003 Elsevier B.V. All rights reserved