Yanling Cai

Exosomes have been implicated in numerous biological processes, and they may serve as important disease markers. Surface proteins on exosomes carry information about their tissues of origin. Because of the heterogeneity of exosomes it is desirable to investigate them individually, but this has so far remained impractical. Here, we demonstrate a proximity-dependent barcoding assay to profile surface proteins of individual exosomes using antibody-DNA conjugates and next-generation sequencing. We first validate the method using artificial streptavidin-oligonucleotide complexes, followed by analysis of the variable composition of surface proteins on individual exosomes, derived from human body fluids or cell culture media. Exosomes from different sources are characterized by the presence of specific combinations of surface proteins and their abundance, allowing exosomes to be separately quantified in mixed samples to serve as markers for tissue-specific engagement in disease.

Emerging telemedicine programs offer potential low-cost solutions to the management of chronic disease. We sought to evaluate the clinical effectiveness and cost effectiveness of telemedicine approaches on glycemic control in patients with type 2 diabetes mellitus. Using terms related to type 2 diabetes and telemedicine, MEDLINE, Cochrane, EMBASE, and CINAHL Plus were searched to identify relevant studies published through February 28, 2014. Data from identified clinical trials were pooled according to telemedicine approach, and evaluated using conventional meta-analytical methods. We identified 47 articles, from 35 randomized controlled trials, reporting quantitative outcomes for hemoglobin A1c (HbA1c). Twelve of the 35 studies provided intervention via telephone, either in the form of a call or a text message; 19 studies tested internet-based programs, employing video-conferencing and/or informational websites; and four studies used interventions involving electronically transmitted recommendations made by clinicians in response to internet-based reporting by patients. Overall, pooled results from these studies revealed a small, but statistically significant, decrease in HbA1c following intervention, compared to conventional treatment (pooled difference in means=-0.37, 95% CI=-0.49 to -0.25, Z=-6.08, P<0.001). Only two of the 35 studies included assessment of cost-effectiveness. These studies were disparate, both in terms of overall expense and relative cost-effectiveness. Optimization of telemedicine approaches could potentially allow for more effective self-management of disease in type 2 diabetes patients, though evidence to-date is unconvincing. Furthermore, significant publication bias was detected, suggesting that the literature should be interpreted cautiously.

In this study we present a scheme for quantitative determination of biofilm viability offering significant improvement over existing methods with metabolic assays. Existing metabolic assays for quantifying viable bacteria in biofilms usually utilize calibration curves derived from planktonic bacteria, which can introduce large errors due to significant differences in the metabolic and/or growth rates of biofilm bacteria in the assay media compared to their planktonic counterparts. In the presented method we derive the specific growth rate of Streptococcus mutans bacteria biofilm from a series of metabolic assays using the pH indicator phenol red, and show that this information could be used to more accurately quantify the relative number of viable bacteria in a biofilm. We found that the specific growth rate of S. mutans in biofilm mode of growth was 0.70 h-1, compared to 1.09 h-1 in planktonic growth. This method should be applicable to other bacteria types, as well as other metabolic assays, and, for example, to quantify the effect of antibacterial treatments or the performance of bactericidal implant surfaces.