Abstract: Background: Prompt diagnosis and treatment of infants born to parents living with HIV is essential to reduce infant mortality. The availability of several high-throughput automated molecular tests is necessary to increase the services of early diagnosis tests in infants, especially in countries with limited resources such as Senegal. Objective: The objective of this study was to compare two automated molecular tests, Roche COBAS®AmpliPrep/COBAS® TaqMan® HIV-1 Qualitative and Abbott RealTime HIV-1 Qualitative in the early diagnosis of HIV-1 infection in children born to HIV-positive mothers in Senegal. Methods: The study was conducted exclusively at the molecular biology laboratory of the armed forces AIDS programme at the Ouakam Military Hospital, Dakar, Senegal, between September 2020 and December 2021. It involved 136 children aged between 1 and 18 months born to HIV-1 infected mothers. The samples were taken from blood obtained from the baby's heel, dried on blotting paper (DBS) and sent to the molecular biology laboratory. They were then stored at room temperature before being tested for the study. After these samples were analysed on both molecular techniques, the Abbott Qualitative results were compared to diagnostic tests performed with Roche COBAS®AmpliPrep/COBAS®TaqMan®HIV-1 Qualitative, which is the reference molecular technique. R Studio software version 099.902, 2016 was used to calculate specificity and sensitivity and Kappa coefficient. For statistical tests, they are considered significant when the P-value is less than 5%. Results: Out of a total of 136 samples tested, the overall positive and negative concordance was 94.84%, 79.41% and 93.58% respectively. The concordance coefficient, Cohen's Kappa coefficient, was also analysed. It gave a value of 0.853 (95% CI: [74.7-95.8]). A discrepancy was found between the two tests. Seven samples, which had previously tested positive on Roche Cobas, tested negative on Abbott Qualitative. Conclusion: The result showed a comparable performance characterized by very good negative, positive and global concordances and also, a very high Cohen's Kappa coefficient κ. The present study showed that the two molecular tests are comparable and that the Abbott Qualitative is a practical alternative for the diagnosis of HIV in infants.Abstract: Background: Prompt diagnosis and treatment of infants born to parents living with HIV is essential to reduce infant mortality. The availability of several high-throughput automated molecular tests is necessary to increase the services of early diagnosis tests in infants, especially in countries with limited resources such as Senegal. Objective: The...Show More
Abstract: Understanding of diffusion of solute particles across the biological partition is very well studied both in vitro and in vivo. Diffusion is the movement of solute molecules by random thermal or Brownian motion across the barriers. Various experimental and mathematical models were employed to study the diffusion characteristics which have also helped to design the experiments and interpretation of data. In the present investigation, we have developed a simple, cost-effective eggshell membrane model for understanding diffusion characteristics. The passive diffusion (in vitro) of sugar molecules through a natural (Chicken egg shell) membrane model was studied. The diffusion coefficient (D), diffusion rate (J), and permeability coefficient (P) in relation to temperature, viscosity of solution, surface area of the membrane, and the molecular size of diffusing molecules have been quantitatively determined. Fick’s first law of diffusion is used for the evaluation of experimental data. All the experiments were carried out at a physiological pH. The diffused solute particles in the donor compartment were measured using UV visible spectroscopy at three different time intervals. Diffusion rate and the permeability coefficient were found to increase with the higher temperature of the solution as well as for the larger surface area of the membrane; however, it decreased with the viscosity and size of the diffusing solute particles. The possible mechanisms and characteristics of the diffusion of the molecules have been elucidated. We conclude that such a model may be useful as a teaching and learning model for diffusion characteristics.
Abstract: Understanding of diffusion of solute particles across the biological partition is very well studied both in vitro and in vivo. Diffusion is the movement of solute molecules by random thermal or Brownian motion across the barriers. Various experimental and mathematical models were employed to study the diffusion characteristics which have also helpe...Show More
