Biomarkers on patient T cells diagnose active tuberculosis and monitor treatment response

BACKGROUND. The identification and treatment of individuals with tuberculosis (TB) is a global public health priority. Accurate diagnosis of pulmonary active TB (ATB) disease remains challenging and relies on extensive medical evaluation and detection of Mycobacterium tuberculosis (Mtb) in the patient’s sputum. Further, the response to treatment is monitored by sputum culture conversion, which takes several weeks for results. Here, we sought to identify blood-based host biomarkers associated with ATB and hypothesized that immune activation markers on Mtb-specific CD4⁺ T cells would be associated with Mtb load in vivo and could thus provide a gauge of Mtb infection.METHODS. Using polychromatic flow cytometry, we evaluated the expression of immune activation markers on Mtb-specific CD4⁺ T cells from individuals with asymptomatic latent Mtb infection (LTBI) and ATB as well as from ATB patients undergoing anti-TB treatment.RESULTS. Frequencies of Mtb-specific IFN-γ⁺CD4⁺ T cells that expressed immune activation markers CD38 and HLA-DR as well as intracellular proliferation marker Ki-67 were substantially higher in subjects with ATB compared with those with LTBI. These markers accurately classified ATB and LTBI status, with cutoff values of 18%, 60%, and 5% for CD38⁺IFN-γ⁺, HLA-DR⁺IFN-γ⁺, and Ki-67⁺IFN-γ⁺, respectively, with 100% specificity and greater than 96% sensitivity. These markers also distinguished individuals with untreated ATB from those who had successfully completed anti-TB treatment and correlated with decreasing mycobacterial loads during treatment.CONCLUSION. We have identified host blood-based biomarkers on Mtb-specific CD4⁺ T cells that discriminate between ATB and LTBI and provide a set of tools for monitoring treatment response and cure.TRIAL REGISTRATION. Registration is not required for observational studies.FUNDING. This study was funded by Emory University, the NIH, and the Yerkes National Primate Center.     

Alcohol consumption patterns and predictors of use following liver transplantation for alcoholic liver disease.

For patients who receive a liver transplant (LTX) for alcoholic liver disease (ALD), investigators are focusing beyond survival to determine specific alcohol use outcomes. Studies suggest the use of alcohol ranges from 8 to 22% for the first post-transplant year with cumulative rates reaching 30 to 40% by 5 years following transplantation. Yet while investigators are interested in determining specific rates of alcohol use and predictors of use, only three studies since 1990 have been prospective. In 1998, we began a prospective study of post-LTX alcohol consumption in ALD recipients using multiple repeated measures of alcohol use. After 5 years of follow-up, we found that 22% had used any alcohol by the first year and 42% had a drink by 5 years. By 5 years, 26% drank at a heavier use (binge) pattern and 20% drank in a frequent pattern. In a univariate model, predictors of alcohol use included pre-transplant length of sobriety, a diagnosis of alcohol dependence, a history of other substance use, and prior alcohol rehabilitation.     

Shape changes produced in detergent extracted bovine retinal pigment epithelium when exposed to ATP. A comparison with fibroblasts and smooth muscle cells

The response of single detergent treated bovine retinal pigment epithelial cells in culture to ATP was measured with an image analyser. The most pronounced contraction was produced by 1.0 mM ATP with most change taking place in the first 10 min. At 1 h the area had decreased by about 33%, perimeter 22% and maximum length 25%. By way of comparison rabbit skin fibroblasts had a decreased area of approximately 40%, perimeter 25% and maximum length 22%. Bovine aortic smooth muscle cells on the other hand decreased in area by 55%, perimeter 40% and maximum length 36%. It is hoped that this assay may be used to evaluate drugs which could counteract contractile events in proliferative vitreoretinopathy.     

Lack of tolerance to nicotine-induced dopamine release in the nucleus accumbens

The extent to which repeated administration produces tolerance to nicotine-induced increases in dopamine transmission in the nucleus accumbens was investigated in rats. In vivo microdialysis was used to sample extracellular dopamine and metabolites after a nicotine challenge (0.35 mg/kg) in (1) naive rats, (2) acutely pretreated rats (1 prior nicotine injection), and (3) chronically pretreated rats (12-15 prior daily nicotine injections, 0.35 mg/kg per injection). Nicotine increased extracellular DA and its metabolites, and these increases were not significantly altered by either acute or chronic prior exposure to the drug. The failure to find evidence of tolerance is compatible with the hypothesis that the mesolimbic dopaminergic system is a substrate for the reinforcing properties of chronically administered nicotine.     

Evidence that drug flux across synthetic membranes is described by normally distributed permeability coefficients.

Over recent decades, the use of in vitro diffusion cell studies to assess skin permeability has evolved into a major research tool, providing key insights into the relationships between skin, drug and formulation. Sometimes, such studies involve synthetic membranes as this approach can yield useful inferences with respect to drug-skin partitioning and diffusion phenomena. Yet despite the popularity of such studies, it is still not at all known whether typical solute transport across synthetic barriers results in a normal distribution of permeability coefficients or alternatively some type of skewed distribution. The present study aims to shed light on this issue. To this end, five compounds (testosterone, oestradiol, corticosterone, aldosterone and adenosine) exhibiting a broad range of octanol-water partition coefficient values were selected as test penetrants. The protocol involved taking multiple replicate measurements of each drug's passive steady state flux through poly(dimethylsiloxane) membrane. Each penetrant's resultant permeability coefficient database was subjected to a Kolmogorov-Smirnov (KS) test for normality. It was found that the permeability coefficients of all five drugs were distributed in a Gaussian-normal fashion. The theoretical significance and practical impact of these findings are discussed.