Utility of CD4 count measurement in the era of universal antiretroviral therapy: an analysis of routine laboratory data in Botswana.

OBJECTIVES: National guidelines in Botswana recommend baseline CD4 count measurement and both CD4 and HIV viral load (VL) monitoring post-antiretroviral therapy (ART) initiation. We evaluated the utility of CD4 count measurement in Botswana in the era of universal ART. METHODS: CD4 and VL data were analysed for HIV-infected adults undergoing CD4 count measurement in 2015-2017 at the Botswana Harvard HIV-Reference Laboratory. We determined (1) the proportion of individuals with advanced HIV disease (CD4 count < 200 cells/µL) at initial CD4 assessment, (2) the proportion with an initial CD4 count ≥ 200 cells/µL experiencing a subsequent decline in CD4 count to < 200 cells/µL, and (3) the proportion of these immunologically failing individuals who had virological failure. Logistic regression modelling examined factors associated with advanced HIV disease. CD4 count trajectories were assessed using locally weighted scatterplot smoothing (LOWESS) regression. RESULTS: Twenty-five per cent (3571/14 423) of individuals with an initial CD4 assessment during the study period had advanced HIV disease at baseline. Older age [≥ 35 years; adjusted odds ratio (aOR) 1.9; 95% confidence interval (CI) 1.8-2.1] and male sex were associated with advanced HIV disease. Fifty per cent (7163/14 423) of individuals had at least two CD4 counts during the study period. Of those with an initial CD4 count ≥ 200 cells/µL, 4% (180/5061) experienced a decline in CD4 count to < 200 cells/µL; the majority of CD4 count declines were in virologically suppressed individuals and transient. CONCLUSIONS: One-quarter of HIV-positive individuals in Botswana still present with advanced HIV disease, highlighting the importance of baseline CD4 count measurement to identify this at-risk population. Few with a baseline CD4 count ≥ 200 cells/µL experienced a drop below 200 cells/µL, suggesting limited utility for ongoing CD4 monitoring.

The temporal unraveling of autobiographical memory narratives in patients with temporal lobe epilepsy or excisions.

Medial temporal lobe epilepsy (TLE), a condition known to affect the integrity and function of medial temporal lobe structures such as the hippocampus, has been shown to disrupt memory for real-life episodes. Here, patients with unilateral TLE, patients who received a unilateral temporal lobe resection to cure TLE, and healthy controls produced free narratives of autobiographical memories (AMs). To assess temporal resolution, narratives were segmented into bits of information, or details, which were classified according to how precisely they could be located within the time course of the AM. Categories included details corresponding to the entire AM, to parts or subevents within the AM, and to actions taking place within seconds to minutes. The number of details per category was tallied and compared between patients and controls. Temporal order was assessed by determining the correct (internally consistent) chronological order of the sequence of events within the narrative. Results indicate that while patients' memory for the parts or subevents of personal episodes was intact, as was their temporal order, their memory for the minute-by-minute unraveling of the episode was impaired. We believe this loss of temporally specific details may contribute to the reduced vividness of AM recollection in TLE patients. Our findings provide further evidence that patients with hippocampal damage retrieve skeletal AMs for which the gist of the memory is maintained, but the specific details are lost.

Evaluation of the impeller shroud performance of an axial flow ventricular assist device using computational fluid dynamics.

Generally, there are two types of impeller design used in the axial flow blood pumps. For the first type, which can be found in most of the axial flow blood pumps, the magnet is embedded inside the impeller hub or blades. For the second type, the magnet is embedded inside the cylindrical impeller shroud, and this design has not only increased the rotating stability of the impeller but has also avoided the flow interaction between the impeller blade tip and the pump casing. Although the axial flow blood pumps with either impeller design have been studied individually, the comparisons between these two designs have not been conducted in the literature. Therefore, in this study, two axial flow blood pumps with and without impeller shrouds were numerically simulated with computational fluid dynamics and compared with each other in terms of hydraulic and hematologic performances. For the ease of comparison, these two models have the same inner components, which include a three-blade straightener, a two-blade impeller, and a three-blade diffuser. The simulation results showed that the model with impeller shroud had a lower static pressure head with a lower hydraulic efficiency than its counterpart. It was also found that the blood had a high possibility to deposit on the impeller shroud inner surface, which greatly enhanced the possibility of thrombus formation. The blood damage indices in both models were around 1%, which was much lower than the 13.1% of the axial flow blood pump of Yano et al. with the corresponding experimental hemolysis of 0.033 g/100 L.

Nonuniversal routes to universality: critical phenomena in colloidal dispersions.

We investigate critical phenomena in colloids by means of the renormalization-group based hierarchical reference theory of fluids. We focus on three experimentally relevant model systems: namely, the Asakura-Oosawa model of a colloidal dispersion under the influence of polymer-induced attractive depletion forces; fluids with competing short-range attractive and longer-range repulsive interactions; solutions of star polymers whose pair potential presents both an attractive well and an ultrasoft repulsion at shorter distance. Our results show that the ability to tune the effective interactions between colloidal particles allows one to generate a variety of crossovers to the asymptotic critical behavior, which are not observed in atomic fluids.

Phase diagram of symmetric binary mixtures at equimolar and nonequimolar concentrations: a systematic investigation.

We consider symmetric binary mixtures consisting of spherical particles with equal diameters interacting via a hard-core plus attractive tail potential with strengths epsilon(ij), i,j=1,2, such that epsilon(11)=epsilon(22)>epsilon(12). The phase diagram of the system at all densities and concentrations is investigated as a function of the unlike-to-like interaction ratio delta=epsilon(12)/epsilon(11) by means of the hierarchical reference theory. The results are related to those of previous investigations performed at equimolar concentration, as well as to the topology of the mean-field critical lines. As delta is increased in the interval 0

Many-body interaction effects on the low-k structure of liquid Kr.

Neutron diffraction measurements and theoretical calculations of the structure factor S(k) of liquid Kr are extended to small k values (k<4 nm(-1)). The results show that many-body interaction contributions have an increasing effect on S(k) as k-->0, reaching at least 40% of the measured intensity. Both the phase diagram and the low-k structural data of dense Kr turn out to be closely reproduced by the hierarchical reference theory if additional many-body forces are taken into account by an augmented strength of the Axilrod-Teller triple-dipole potential. The experimental density derivative of S(k) is also used for a very sensitive test of the theories and interaction models considered here.