Laboratory-based ROTEM(®) analysis: implementing pneumatic tube transport and real-time graphic transmission

ROTEM(®) is considered a helpful point-of-care device to monitor blood coagulation. Centrally performed analysis is desirable but rapid transport of blood samples and real-time transmission of graphic results are an important prerequisite. The effect of sample transport through a pneumatic tube system on ROTEM(®) results is unknown. The aims of the present work were (i) to determine the influence of blood sample transport through a pneumatic tube system on ROTEM(®) parameters compared to manual transportation, and (ii) to verify whether graphic results can be transmitted on line via virtual network computing using local area network to the physician in charge of the patient.

Virologic failure and second-line antiretroviral therapy in children in South Africa--the IeDEA Southern Africa collaboration

Background: With expanding pediatric antiretroviral therapy (ART) access, children will begin to experience treatment failure and require second-line therapy. We evaluated the probability and determinants of virologic failure and switching in children in South Africa. Methods: Pooled analysis of routine individual data from children who initiated ART in 7 South African treatment programs with 6-monthly viral load and CD4 monitoring produced Kaplan-Meier estimates of probability of virologic failure (2 consecutive unsuppressed viral loads with the second being >1000 copies/mL, after ≥24 weeks of therapy) and switch to second-line. Cox-proportional hazards models stratified by program were used to determine predictors of these outcomes. Results: The 3-year probability of virologic failure among 5485 children was 19.3% (95% confidence interval: 17.6 to 21.1). Use of nevirapine or ritonavir alone in the initial regimen (compared with efavirenz) and exposure to prevention of mother to child transmission regimens were independently associated with failure [adjusted hazard ratios (95% confidence interval): 1.77 (1.11 to 2.83), 2.39 (1.57 to 3.64) and 1.40 (1.02 to 1.92), respectively]. Among 252 children with ≥1 year follow-up after failure, 38% were switched to second-line. Median (interquartile range) months between failure and switch was 5.7 (2.9-11.0). Conclusions: Triple ART based on nevirapine or ritonavir as a single protease inhibitor seems to be associated with a higher risk of virologic failure. A low proportion of virologically failing children were switched.

Negative impact of the noseclip on high-frequency respiratory impedance measurements

The noseclip is conventionally used in lung function testing to prevent leakage via the nasal compartments. However, some subjects exhibit a velum-opening reflex which may affect results. We performed forced oscillation measurements at frequencies (8-256 Hz) that include the first antiresonance, comparing the noseclip with a cotton wool nose plug to eliminate upper airway contribution. Three sets of measurements were made in 18 adults: with and without noseclip, and with cotton wool. Velum opening during noseclip measurements was monitored using a nasal pressure transducer. A significantly greater proportion of subjects produced a characteristic distortion to the first antiresonance with the noseclip than with either no noseclip or with cotton wool. Distortion of the spectrum coincided with the transmission of oscillations into the nasal cavity. Thus, the noseclip cannot be used in high-frequency forced oscillation measurements because of the velum reflex. The cotton wool plug offers a simple alternative. This effect has unknown impact in other lung function tests.

On-chip non-invasive and label-free cell discrimination by impedance spectroscopy

OBJECTIVES: Many flow-cytometric cell characterization methods require costly markers and colour reagents. We present here a novel device for cell discrimination based on impedance measurement of electrical cell properties in a microfluidic chip, without the need of extensive sample preparation steps and the requirement of labelling dyes. MATERIALS AND METHODS, RESULTS: We demonstrate that in-flow single cell measurements in our microchip allow for discrimination of various cell line types, such as undifferentiated mouse fibroblasts 3T3-L1 and adipocytes on the one hand, or human monocytes and in vitro differentiated dendritic cells and macrophages on the other hand. In addition, viability and apoptosis analyses were carried out successfully for Jurkat cell models. Studies on several species, including bacteria or fungi, demonstrate not only the capability to enumerate these cells, but also show that even other microbiological life cycle phases can be visualized. CONCLUSIONS: These results underline the potential of impedance spectroscopy flow cytometry as a valuable complement to other known cytometers and cell detection systems.

Particles induce apical plasma membrane enlargement in epithelial lung cell line depending on particle surface area dose

Background Airborne particles entering the respiratory tract may interact with the apical plasma membrane (APM) of epithelial cells and enter them. Differences in the entering mechanisms of fine (between 0.1 μm and 2.5 μm) and ultrafine ( ≤ 0.1 μm) particles may be associated with different effects on the APM. Therefore, we studied particle-induced changes in APM surface area in relation to applied and intracellular particle size, surface and number. Methods Human pulmonary epithelial cells (A549 cell line) were incubated with various concentrations of different sized fluorescent polystyrene spheres without surface charge (∅ fine – 1.062 μm, ultrafine – 0.041 μm) by submersed exposure for 24 h. APM surface area of A549 cells was estimated by design-based stereology and transmission electron microscopy. Intracellular particles were visualized and quantified by confocal laser scanning microscopy. Results Particle exposure induced an increase in APM surface area compared to negative control (p < 0.01) at the same surface area concentration of fine and ultrafine particles a finding not observed at low particle concentrations. Ultrafine particle entering was less pronounced than fine particle entering into epithelial cells, however, at the same particle surface area dose, the number of intracellular ultrafine particles was higher than that of fine particles. The number of intracellular particles showed a stronger increase for fine than for ultrafine particles at rising particle concentrations. Conclusion This study demonstrates a particle-induced enlargement of the APM surface area of a pulmonary epithelial cell line, depending on particle surface area dose. Particle uptake by epithelial cells does not seem to be responsible for this effect. We propose that direct interactions between particle surface area and cell membrane cause the enlargement of the APM.

High Resolution Transmission Spectroscopy as a Diagnostic for Jovian Exoplanet Atmospheres: Constraints from Theoretical Models

We present high resolution transmission spectra of giant planet atmospheres from a coupled 3-D atmospheric dynamics and transmission spectrum model that includes Doppler shifts which arise from winds and planetary motion. We model jovian planets covering more than two orders of magnitude in incident flux, corresponding to planets with 0.9 to 55 day orbital periods around solar-type stars. The results of our 3-D dynamical models reveal certain aspects of high resolution transmission spectra that are not present in simple 1-D models. We find that the hottest planets experience strong substellar to anti-stellar (SSAS) winds, resulting in transmission spectra with net blue shifts of up to 3 km s−1, whereas less irradiated planets show almost no net Doppler shifts. Compared to 1-D models, peak line strengths are significantly reduced for the hottest atmospheres owing to Doppler broadening from a combination of rotation (which is faster for close-in planets under the assumption of tidal locking) and atmospheric winds. Finally, high resolution transmission spectra may be useful in studying the atmospheres of exoplanets with optically thick clouds since line cores for very strong transitions should remain optically thick to very high altitude. High resolution transmission spectra are an excellent observational test for the validity of 3-D atmospheric dynamics models, because they provide a direct probe of wind structures and heat circulation. Ground-based exoplanet spectroscopy is currently on the verge of being able to verify some of our modeling predictions, most notably the dependence of SSAS winds on insolation. We caution that interpretation of high resolution transmission spectra based on 1-D atmospheric models may be inadequate, as 3-D atmospheric motions can produce a noticeable effect on the absorption signatures.

The need for second-line antiretroviral therapy in adults in sub-Saharan Africa up to 2030: a mathematical modelling study.

BACKGROUND The number of patients in need of second-line antiretroviral drugs is increasing in sub-Saharan Africa. We aimed to project the need of second-line antiretroviral therapy in adults in sub-Saharan Africa up to 2030. METHODS We developed a simulation model for HIV and applied it to each sub-Saharan African country. We used the WHO country intelligence database to estimate the number of adult patients receiving antiretroviral therapy from 2005 to 2014. We fitted the number of adult patients receiving antiretroviral therapy to observed estimates, and predicted first-line and second-line needs between 2015 and 2030. We present results for sub-Saharan Africa, and eight selected countries. We present 18 scenarios, combining the availability of viral load monitoring, speed of antiretroviral scale-up, and rates of retention and switching to second-line. HIV transmission was not included. FINDINGS Depending on the scenario, 8·7-25·6 million people are expected to receive antiretroviral therapy in 2020, of whom 0·5-3·0 million will be receiving second-line antiretroviral therapy. The proportion of patients on treatment receiving second-line therapy was highest (15·6%) in the scenario with perfect retention and immediate switching, no further scale-up, and universal routine viral load monitoring. In 2030, the estimated range of patients receiving antiretroviral therapy will remain constant, but the number of patients receiving second-line antiretroviral therapy will increase to 0·8-4·6 million (6·6-19·6%). The need for second-line antiretroviral therapy was two to three times higher if routine viral load monitoring was implemented throughout the region, compared with a scenario of no further viral load monitoring scale-up. For each monitoring strategy, the future proportion of patients receiving second-line antiretroviral therapy differed only minimally between countries. INTERPRETATION Donors and countries in sub-Saharan Africa should prepare for a substantial increase in the need for second-line drugs during the next few years as access to viral load monitoring improves. An urgent need exists to decrease the costs of second-line drugs. FUNDING World Health Organization, Swiss National Science Foundation, National Institutes of Health.

Decreasing Proportion of Recent Infections among Newly Diagnosed HIV-1 Cases in Switzerland, 2008 to 2013 Based on Line-Immunoassay-Based Algorithms.

BACKGROUND: HIV surveillance requires monitoring of new HIV diagnoses and differentiation of incident and older infections. In 2008, Switzerland implemented a system for monitoring incident HIV infections based on the results of a line immunoassay (Inno-Lia) mandatorily conducted for HIV confirmation and type differentiation (HIV-1, HIV-2) of all newly diagnosed patients. Based on this system, we assessed the proportion of incident HIV infection among newly diagnosed cases in Switzerland during 2008-2013. METHODS AND RESULTS: Inno-Lia antibody reaction patterns recorded in anonymous HIV notifications to the federal health authority were classified by 10 published algorithms into incident (up to 12 months) or older infections. Utilizing these data, annual incident infection estimates were obtained in two ways, (i) based on the diagnostic performance of the algorithms and utilizing the relationship 'incident = true incident + false incident', (ii) based on the window-periods of the algorithms and utilizing the relationship 'Prevalence = Incidence x Duration'. From 2008-2013, 3'851 HIV notifications were received. Adult HIV-1 infections amounted to 3'809 cases, and 3'636 of them (95.5%) contained Inno-Lia data. Incident infection totals calculated were similar for the performance- and window-based methods, amounting on average to 1'755 (95% confidence interval, 1588-1923) and 1'790 cases (95% CI, 1679-1900), respectively. More than half of these were among men who had sex with men. Both methods showed a continuous decline of annual incident infections 2008-2013, totaling -59.5% and -50.2%, respectively. The decline of incident infections continued even in 2012, when a 15% increase in HIV notifications had been observed. This increase was entirely due to older infections. Overall declines 2008-2013 were of similar extent among the major transmission groups. CONCLUSIONS: Inno-Lia based incident HIV-1 infection surveillance proved useful and reliable. It represents a free, additional public health benefit of the use of this relatively costly test for HIV confirmation and type differentiation.