Some factors affecting performance of rats in the traveling salesman problem.

The traveling salesman problem (TSP) is used to measure the efficiency of spatial route selection. Among researchers in cognitive psychology and neuroscience, it has been utilized to examine the mechanisms of decision making, planning, and spatial navigation. While both human and non-human animals produce good solutions to the TSP, the solution strategies engaged by non-human species are not well understood. We conducted two experiments on the TSP using Long-Evans laboratory rats as subjects. The first experiment examined the role of arena walls in route selection. Rats tend to display thigmotaxis in testing conditions comparable to the TSP, which could produce results similar to a convex hull type strategy suggested for humans. The second experiment examined the role of turn angle between targets along the optimal route, to determine whether rats exhibit a preferential turning bias. Our results indicated that both thigmotaxis and preferential turn angles do affect performance in the TSP, but neither is sufficient as a predictor of route choice in this task.

Fibrosis assessment in patients with nonalcoholic fatty liver disease: Adherence to proposed algorithms and barriers to complying with them.

INTRODUCTION AND AIMS: Fibrosis staging in patients with nonalcoholic fatty liver disease (NAFLD) is carried out through the application of stepwise algorithms but there is little real-world data on their use. Our aim was to calculate the number of patients with NAFLD and indeterminate or high risk for fibrosis, assessed through noninvasive scores, that consequently underwent further staging evaluation. MATERIALS AND METHODS: A cross-sectional multicenter cohort study was conducted on patients with NAFLD evaluated by hepatologists within the time frame of June 1 and July 31, 2018. The FIB-4 and NAFLD fibrosis scores were calculated in all the patients, and if at least one of the scores suggested indeterminate or high risk for fibrosis, we believed the patient should have undergone additional fibrosis staging assessment. RESULTS: The study included 238 patients. The median time interval from NAFLD diagnosis and inclusion in the analysis was 12.2 months (IQR 3.0-36.5). A total of 128 (54%) patients had at least one noninvasive score that suggested indeterminate or high risk for fibrosis but studies to confirm the fibrosis grade (elastography, biopsy, etc.) were performed on only 72 (56%). The main barriers encountered by the physicians for applying the staging algorithms were related to health insurance coverage and imaging study costs. CONCLUSIONS: A high percentage of patients with NAFLD were at indeterminate or high risk for fibrosis, according to noninvasive scores, but additional studies were carried out on only half of them, showing low adherence to current recommendations.

Fibrosis assessment in patients with nonalcoholic fatty liver disease: Adherence to proposed algorithms and barriers to complying with them. / Evaluación de fibrosis en pacientes con enfermedad por hígado graso no alcohólico: adherencia a los algoritmos propuestos y barreras para cumplir con ellos.

INTRODUCTION AND AIMS: Fibrosis staging in patients with nonalcoholic fatty liver disease (NAFLD) is carried out through the application of stepwise algorithms but there is little real-world data on their use. Our aim was to calculate the number of patients with NAFLD and indeterminate or high risk for fibrosis, assessed through noninvasive scores, that consequently underwent further staging evaluation. MATERIALS AND METHODS: A cross-sectional multicenter cohort study was conducted on patients with NAFLD evaluated by hepatologists within the time frame of June 1 and July 31, 2018. The FIB-4 and NAFLD fibrosis scores were calculated in all the patients, and if at least one of the scores suggested indeterminate or high risk for fibrosis, we believed the patient should have undergone additional fibrosis staging assessment. RESULTS: The study included 238 patients. The median time interval from NAFLD diagnosis and inclusion in the analysis was 12.2months (IQR 3.0-36.5). A total of 128 (54%) patients had at least one noninvasive score that suggested indeterminate or high risk for fibrosis but studies to confirm the fibrosis grade (elastography, biopsy, etc.) were performed on only 72 (56%). The main barriers encountered by the physicians for applying the staging algorithms were related to health insurance coverage and imaging study costs. CONCLUSIONS: A high percentage of patients with NAFLD were at indeterminate or high risk for fibrosis, according to noninvasive scores, but additional studies were carried out on only half of them, showing low adherence to current recommendations.

Caspase-1 inhibitors abolish deleterious enhancement of COX-2 expression induced by HIV-1 gp120 in human neuroblastoma cells.

The human CHP100 neuroblastoma cell line has been shown to provide an useful in vitro model to elucidate the mechanisms underlying HIV-1 gp120 neurotoxicity. Here we report western blotting evidence demonstrating that exposure to a cytotoxic concentration of the viral coat protein up-regulates expression of the inducible isoform of cyclooxygenase (COX-2) in neuroblastoma cells and this seems to be due to the previously observed increase in secreted IL-1beta. In fact, here we show that acetyl-Tyr-Val-Ala-Asp-chloromethylketone (Ac-YVAD-CMK) and t-butoxycarbonyl-L-aspartic acid benzyl ester-chloromethylketone (Boc-Asp-(OBzl)-CMK), two inhibitors of Interleukin-1 Converting Enzyme (ICE; also referred to as caspase-1), abolish COX-2 expression enhanced by gp120 and consequent cell death. In addition, NS-398, a selective inhibitor of COX-2 activity, affords neuroprotection strengthening the role of COX-2 in the mechanisms of death. In conclusion, the present data support the notion that IL-1beta is the signal through which gp120 elevates COX-2 expression and the latter is strongly implicated in the mechanisms underlying cytotoxicity.