Thin Polymer Brush Decouples Biomaterial's Micro-/Nano-Topology and Stem Cell Adhesion

Surface morphology and chemistry of polymers used as biomaterials, such as tissue engineering scaffolds, have a strong influence on the adhesion and behavior of human mesenchymal stem cells. Here we studied semicrystalline poly(ε-caprolactone) (PCL) substrate scaffolds, which exhibited a variation of surface morphologies and roughness originating from different spherulitic superstructures. Different substrates were obtained by varying the parameters of the thermal processing, i.e. crystallization conditions. The cells attached to these polymer substrates adopted different morphologies responding to variations in spherulite density and size. In order to decouple substrate topology effects on the cells, sub-100 nm bio-adhesive polymer brush coatings of oligo(ethylene glycol) methacrylates were grafted from PCL and functionalized with fibronectin. On surfaces featuring different surface textures, dense and sub-100 nm thick brush coatings determined the response of cells, irrespective to the underlying topology. Thus, polymer brushes decouple substrate micro-/nano-topology and the adhesion of stem cells

Implementation and outcomes of a patient tracing programme for HIV in Trinidad and Tobago

A patient tracing programme was implemented at an HIV clinic in Trinidad and Tobago to address the problem of defaulters from HIV care and non-adherence to antiretroviral treatment (ART). The study objective was to evaluate the implementation and outcomes of this programme conducted between April and September 2017. Using patient tracing contact methods, trained social workers attempted to contact 1058 patients lost to follow up (LTFU) between July 2016 and March 2017. Of the 1058 LTFU, 192 were ineligible: 27 (2.5%) were transferred to another clinic, 64 (6%) deceased, 35 (3.3%) hospitalised, 50 (4.7%) migrated and 16 (1.5%) incarcerated. Of the 866 eligible patients for patient tracing, 277 (32%) remained permanently LTFU and 589 (68%) were successfully contacted, re-engaged in care and received adherence counselling. Of the 589 who returned to care, 507 (86%) restarted ART. The three most common barriers reported among the 589 who were reengaged were ‘forgetting their appointments’ (20%), ‘being too busy/work’ (16%), and ‘not wanting to be seen attending the HIV clinic’ (12%). The study findings demonstrated the tracing programme as feasible for re-engaging those who are LTFU and highlighted barriers that can be addressed to further improve retention in HIV care among people living with HIV

The incidence of histoplasmosis and cryptococcal antigenemia among patients attending a large HIV clinic in Trinidad

Our aim was to determine the incidence disseminated histoplasmosis and cryptococcal antigenemia among 280 patients with a CD4&lt;350 cells/mm3 attending a large HIV clinic in Trinidad over the period November 2021-June 2022. Sera were screened for cryptococcal antigen (CrAg) using the Immy CrAg Immunoassay (EIA) and the Immy CrAg lateral flow assay (LFA). Urine was screened for Histoplasma antigen using the Immy EIA and the Optimum Imaging Diagnostics (OIDx) LFA. For the purposes of analysis, it was assumed, that all patients with positive urine Histoplasma antigen tests by both EIA and LFA and those with a single positive urine Histoplasma antigen test and clinical features of disseminated histoplasmosis were true positives. The incidence of probable disseminated histoplasmosis and cryptococcal antigenemia were 6.4% (18/280) and 2.5% (7/280) respectively. The sensitivity and specificity of the Immy Histoplasma EIA were 100% (95% CI, 81.5%-100%) and 98.5% (95% CI, 96.1% - 99.6%) respectively as compared to the OIDx Histoplasma LFA of 88.9% (95% CI, 65.3% - 98.6%) and 93.9% (95% CI, 90.3% - 96.5%) respectively, with substantial agreement between the 2 test kits (Kappa value = 0.763; 95% CI 0.685, 0.841). Testing for disseminated histoplasmosis in HIV patients is important in endemic areas.</p