Functional Crosstalk between Type I and II Interferon through the Regulated Expression of STAT1

Small "priming" quantities of type I interferon enhance cellular responses to type II interferon by maintaining basal levels of STAT1, explaining the observed crosstalk between these two cytokines

The Effects of Oral Consumption of Selenium Nanoparticles on Chemotactic and Respiratory Burst Activities of Neutrophils in Comparison with Sodium Selenite in Sheep

The present study was designed to compare the effects of nano-selenium and of sodium selenite on the chemotactic and respiratory burst activities of neutrophils in sheep. Fifteen sheep were randomly divided into three groups. Groups 1 and 2 received selenium nanoparticles (1 mg/kg) or sodium selenite (1 mg/kg) orally, respectively, for ten consecutive days, and the third group was considered as the control. To determine the chemotactic and respiratory burst activities of the neutrophils, the leading front assay and the NBT test were used on heparinized blood samples that were collected at different intervals (days 0, 10th, 20th, and 30th). The results obtained showed that the chemotactic activities in groups 1 and 2 increased significantly on the 10th, 20th, and 30th day, compared to day 0, and on the 20th day in comparison with the 10th day, while in group 2, there was a significant decrease on the 30th day compared to the 20th day. The chemotactic activities in group 1 were significantly higher than in group 2 on the 10th day and in the control group on the 10th, 20th, and 30th day, but the chemotactic activities in group 2 were significantly higher than those in the control group only on the 20th day. On the 30th day into the experiment, the respiratory bursts in groups 1 and 2 were significantly stronger in comparison with those at day 0. Overall, nano-selenium increased the chemotactic and respiratory burst activities more significantly than sodium selenite, which is suggestive of a stronger stimulatory effect of the Se nanoparticles on intracellular activities

Speed/Accuracy Trade-Off between the Habitual and the Goal-Directed Processes

Instrumental responses are hypothesized to be of two kinds: habitual and goal-directed, mediated by the sensorimotor and the associative cortico-basal ganglia circuits, respectively. The existence of the two heterogeneous associative learning mechanisms can be hypothesized to arise from the comparative advantages that they have at different stages of learning. In this paper, we assume that the goal-directed system is behaviourally flexible, but slow in choice selection. The habitual system, in contrast, is fast in responding, but inflexible in adapting its behavioural strategy to new conditions. Based on these assumptions and using the computational theory of reinforcement learning, we propose a normative model for arbitration between the two processes that makes an approximately optimal balance between search-time and accuracy in decision making. Behaviourally, the model can explain experimental evidence on behavioural sensitivity to outcome at the early stages of learning, but insensitivity at the later stages. It also explains that when two choices with equal incentive values are available concurrently, the behaviour remains outcome-sensitive, even after extensive training. Moreover, the model can explain choice reaction time variations during the course of learning, as well as the experimental observation that as the number of choices increases, the reaction time also increases. Neurobiologically, by assuming that phasic and tonic activities of midbrain dopamine neurons carry the reward prediction error and the average reward signals used by the model, respectively, the model predicts that whereas phasic dopamine indirectly affects behaviour through reinforcing stimulus-response associations, tonic dopamine can directly affect behaviour through manipulating the competition between the habitual and the goal-directed systems and thus, affect reaction time

Protective Role of Bone Marrow Derived Mesenchymal Stem Cells-Conditioned Medium in the Infarcted Myocardium: The Potential Role of Selected Cytokines

This study examines the protective effects of mesenchymal stem cell-conditioned (CM) medium on heart tissue after induced myocardial infarction (MI). New Zealand White Rabbits were divided: MI, mesenchymal stem cells (MSC) (300 µl), CM(300 µl) and Control. Echocardiography was applied, and the levels ofIL-6, TGF-β and TNF-α were analyzed using ELISA. All tests were done 1, 4 and 8 weeks after the surgery. Histological studies were done 8 weeks after surgery. CM group showed a significant improvement in cardiac function. The level of IL-6 increased significantly in all weeks after surgery in CM. While the level of TNF-α increased remarkebly in CM group in 4th week. TGF-β decreased significantly in CM group at all the times. Histological findings confirmed the tissue protection effect of CM. In conclusion, our results support the protective role of CM through its paracrine effects on the MI-induced heart