Reversing the course of the competitive adsorption between a phospholipid and albumin at an air-water interface

When bovine serum albumin (BSA) and dipalmitoylphosphatidylcholine (DPPC) compete for occupation of an air–water interface, the protein rapidly colonizes the interface, effectively hindering the access of the phospholipid, a situation encountered in certain pulmonary conditions. We found that DPPC can totally and irreversibly displace BSA from the surface of a gas bubble when submitted to sustained sinusoidal oscillations at frequencies in the range of those encountered in respiration, and this without recourse to any additive

Vietnamese trials with a thermostable Newcastle disease vaccine (strain I2) in experimental and village chickens

The Australian I strain of Newcastle disease virus was tested as a vaccine in the laboratory and in Vietnamese villages. The infectivity titre of lyophilised vaccine fell less than 1 log unit on storage for 6 days at 26-32°C. Vaccine stored at similar temperatures induced high levels of immunity in laboratory chickens after storage for 17 days and in village chickens after storage for 21 days. I vaccine protected for at least 24 weeks after vaccination, and for 16 weeks after application in drinking water. Under laboratory conditions, I vaccine given by eye drop spread by contact to unvaccinated chickens, inducing in them both an antibody response and protective immunity. In villages, chickens vaccinated by eye drop, chickens receiving vaccine on food and chickens in contact with vaccinated chickens all resisted artificial challenge 6 weeks after vaccination. There were no adverse reactions to vaccination. Strain I was judged to be thermostable, avirulent and immunogenic, and suitable for use as a vaccine under village conditions

A Nonpolar, Nonamphiphilic Molecule Can Accelerate Adsorption of Phospholipids and Lower Their Surface Tension at the Air/Water Interface

The adsorption dynamics of a series of phospholipids (PLs) at the interface between an aqueous solution or dispersion of the PL and a gas phase containing the nonpolar, nonamphiphilic linear perfluorocarbon perfluorohexane (PFH) was studied by bubble profile analysis tensiometry. The PLs investigated were dioctanoylphosphatidylcholine (DiC8‐PC), dilaurylphosphatidylcholine, dimyristoylphosphatidylcholine, and dipalmitoylphosphatidylcholine. The gas phase consisted of air or air saturated with PFH. The perfluorocarbon gas was found to have an unexpected, strong effect on both the adsorption rate and the equilibrium interfacial tension (γeq) of the PLs. First, for all of the PLs, and at all concentrations investigated, the γeq values were significantly lower (by up to 10 mN m−1) when PFH was present in the gas phase. The efficacy of PFH in decreasing γeq depends on the ability of PLs to form micelles or vesicles in water. For vesicles, it also depends on the gel or fluid state of the membranes. Second, the adsorption rates of all the PLs at the interface (as assessed by the time required for the initial interfacial tension to be reduced by 30 %) are significantly accelerated (by up to fivefold) by the presence of PFH for the lower PL concentrations. Both the surface‐tension reducing effect and the adsorption rate increasing effect establish that PFH has a strong interaction with the PL monolayer and acts as a cosurfactant at the interface, despite the absence of any amphiphilic character. Fitting the adsorption profiles of DiC8‐PC at the PFH‐saturated air/aqueous solution interface with the modified Frumkin model indicated that the PFH molecule lay horizontally at the interface

Counteracting the inhibitory effect of proteins towards lung surfactant substitutes: a fluorocarbon gas helps displace albumin at the air/water interface:

Perfluorohexane gas lowers the kinetic barrier that opposes the displacement of albumin by dipalmitoylphosphatidylcholine at the air/water interface submitted to sinusoidal oscillations at frequencies in the range of those encountered in respiration

Transforming medical education to strengthen the health professional training in Viet Nam: A case study

The competency-based undergraduate curriculum reform at the University of Medicine and Pharmacy at Ho Chi Minh City, Faculty of Medicine (UMP-FM) is detailed and reviewed in reference to the instructional and institutional reforms, and enabling actions recommended by the Lancet 2010 Commission for Health Professional Education. Key objectives are to: revise the overall 6-year curriculum to be more integrated and competency-based; reinforce students’ knowledge application, problem-solving, clinical competence, self-directed learning and soft skills; develop a comprehensive and performance-based student assessment programme; and establish a comprehensive quality monitoring programme to facilitate changes and improvements. New features include early introduction to the practice of medicine, family- and community-based medicine, professionalism, interprofessional education, electives experiences, and a scholarly project. Institutional reform introduces a faculty development programme, joint planning mechanism, a “culture of critical inquiry”, and a transparent faculty reward system. Lessons learnt from the curriculum reform at UMP-FM could be helpful to medical schools from low- and middle-income countries considering transitioning from a traditional to a competency-based curriculum

Viral load testing to monitor the HIV epidemic among PWID in Vietnam

Objective: To share Vietnam’s experiences piloting the integration of viral load (VL) testing into the national HIV sentinel surveillance (HSS) system to better understand the level of HIV viral transmission among people who inject drugs (PWID).Introduction: Vietnam initiated the HSS system in 1994 in selected provinces with high HIV burden. The surveillance has two components: monitor HIV sero-prevalence and risk behaviors among key population including PWID. However, no VL data were collected among HIV infected people. In 2016, Vietnam piloted an added component of VL testing to the existing HSS system. The purpose was to test the feasibility of adding VL testing to the HSS so that VL data among PWID would be available. The pilot was conducted in two provinces in southern Vietnam-Ho Chi Minh City and Long An. It was expected that adding the VL testing to the existing HSS would also save resources and help monitor HIV viral transmission among PWID in the community regardless if they are currently on anti-retroviral therapy (ART).Methods: Male PWIDs were enrolled into 2016 HSS+ following the standard operating procedure (SOP)[1]. Community-based sampling was based on random selection of wards/communes listed in the sampling frame. In each selected ward/commune, all eligible PWID were invited to voluntarily participate in the survey. Eligibility criteria were males 16 years of age or older, reporting injecting drug in the past month, and residing in the selected area. . The survey included an interview using a standardized questionnaire and 7ml blood drawn for HIV testing. Blood specimens were transferred from districts to provincial labs for plasma separation in the same day. Each plasma specimen was divided into three aliquots of 1ml each. One aliquot was used to test for HIV diagnosis at provincial labs, using the national HIV testing strategy III[2]. The remaining 2 aliquots were stored at provincial labs at 2-80C and within 5 days, were shipped to Pasteur Institute in Ho Chi Minh City (PIHCM) where the plasma specimens were stored at -800C. Processing of samples for VL testing was conducted at the end of the survey where all plasma specimen were transferred to PIHCM lab, which was 2 months since the collection of the first blood specimen. VL was undertaken on COBAS AMPLYPREP/COBAS TAQMAN 48, with identification threshold 20 cps/ml and specificity of 100% using Kit CAP-G/CTM HIV-1 V 2.0. The VL testing results were sent back to relevant Provicial AIDS Centers to return to respective participants, within 3 months.Results: Five hundred male PWID (HCMC: 300; LA: 200) were enrolled into 2016 HSS/HSS+ and agreed to provide blood specimen without any refusal. 84 tested positive for HIV (16.8%. HCMC: 15.0%; LA: 19.5%), 43 (51.2%) specimens had unsuppressed VL (>1000 copies/ml) (HCMC: 66.7%; LA: 33.3%), 35 (41.7%) specimens had undetected level (<50 copies/ml or undetected) (HCMC: 31.1%; LA: 53.9%), and 7.1% had VL that ranged from 50-1000 copies/ml (HCMC: 2.2%; LA: 12.8%). Among those who had VL < 1000 copies/ml, 22 (53.7%) had ever been on ART.Conclusions: The pilot survey has measured VL among male PWID, including those who were aware of their HIV status and those who did not know their status before. Findings indicate that a significant proportion of PWID do not have their VL suppressed leading to high-risk of HIV transmission from PWID to their sexual partners[3] in the community although level of unsuppressed viral load is not a direct measure of HIV viral transmission in itself. This pilot indicated that it was feasible to add VL testing into HSS and Vietnam government can add it as a routine practice in HSS and can be expanded in the coming years

Evaluation of the Luminex xTAG Respiratory Viral Panel FAST v2 assay for detection of multiple respiratory viral pathogens in nasal and throat swabs in Vietnam [version 1; referees: 2 approved]

Background: Acute respiratory infections (ARI) are among the leading causes of hospitalization in children ≤5 years old. Rapid diagnostics of viral pathogens is essential to avoid unnecessary antibiotic treatment, thereby slowing down antibiotic-resistance. We evaluated the diagnostic performance of the Luminex xTAG Respiratory Viral Panel FAST v2 against viral specific PCR as reference assays for ARI in Vietnam. Methods: Four hundred and forty two nose and throat swabs were collected in viral transport medium, and were tested with Luminex xTAG Respiratory Viral Panel FAST v2. Multiplex RT-PCR and single RT-PCR were used as references. Results: Overall, viral pathogens were detected in a total count of 270/294 (91.8%, 95% CI 88.1-94.7) by the Luminex among reference assays, whilst 112/6336 (1.8%, 95% CI, 1.4-2.1) of pathogens were detected by the Luminex, but not by reference assays. Frequency of pathogens detected by Luminex and reference assays was 379 and 292, respectively. The diagnostic yield was 66.7% (295/442, 95%CI 62.1-71.1%) for the Luminex assay and 54.1% (239/442, 95% CI, 49.3-58.8%) for reference assays. The Luminex kit had higher yields for all viruses except influenza B virus, respiratory syncytial virus, and human bocavirus. High agreements between both methods [mean (range): 0.91 (0.83-1.00)] were found for 10/15 viral agents. Conclusions: The Luminex assay is a high throughput multiplex platform for rapid detection of common viral pathogens causing ARI. Although the current high cost may prevent Luminex assays from being widely used, especially in limited resource settings where ARI are felt most, its introduction in clinical diagnostics may help reduce unnecessary use of antibiotic prescription