Development of an ex vivo model for the study of cerebrovascular function utilizing isolated mouse olfactory artery

OBJECTIVE: Cerebral vessels, such as intracerebral perforating arterioles isolated from rat brain, have been widely used as an ex vivo model to study the cerebrovascular function associated with cerebrovascular disorders and the therapeutic effects of various pharmacological agents. These perforating arterioles, however, have demonstrated differences in the vascular architecture and reactivity compared with a larger leptomeningeal artery which has been commonly implicated in cerebrovascular disease. In this study, therefore, we developed the method for studying cerebrovascular function utilizing the olfactory artery isolated from the mouse brain. METHODS: The olfactory artery (OA) was isolated from the C57/BL6 wild-type mouse brain. After removing connective tissues, one side of the isolated vessel segment (approximately -500 µm in length) was cannulated and the opposite end of the vessel was completely sealed while being viewed with an inverted microscope. After verifying the absence of pressure leakage, we examined the vascular reactivity to various vasoactive agents under the fixed intravascular pressure (60 mm Hg). RESULTS: We found that the isolated mouse OAs were able to constrict in response to vasoconstrictors, including KCl, phenylephrine, endothelin-1, and prostaglandin PGH(2). Moreover, this isolated vessel demonstrated vasodilation in a dose-dependent manner when vasodilatory agents, acetylcholine and bradykinin, were applied. CONCLUSION: Our findings suggest that the isolated olfactory artery would provide as a useful ex vivo model to study the molecular and cellular mechanisms of vascular function underlying cerebrovascular disorders and the direct effects of such disease-modifying pathways on cerebrovascular function utilizing pharmacological agents and genetically modified mouse models

Joint Link Scheduling and Routing for Load Balancing in STDMA Wireless Mesh Networks

In wireless mesh networks, it is known to be effective to use a TDMA based MAC than a contention-based CSMA. In addition, if spatial TDMA is used, network performance can be improved further because of its spatial reuse effect. However this scheme still has a disadvantage in the system performance aspect without a load-balanced routing because the resource of links that are not used is wasted and frequently used links are out of resources. That is, the number of available flows in network is limited because load balancing is not performed. In this paper, we propose joint link scheduling and routing through a cross-layer scheme. For this, we propose a load balancing routing method to maximize available resources under the given traffic pattern and scheduling method for maximizing link utilization on the given route. These two methods are iterated until an optimized solution can be obtained. The proposed algorithm can be formulated using a mathematical LP problem and we show that it is very effective for load balancing compared to simple adoption of IEEE 802.11s which is a standard TDMA protocol in wireless mesh network. If the proposed algorithm is applied to initial design solution such as Smart Grid, the number of available flows can be increased and the load on each link can be balanced

An Exploratory Study of the Effects of Price Decreases on Online Product Reviews: Focusing on Amazon’s Kindle 2

As online shopping proliferates, online product reviews (OPRs) play a crucial role in online consumers’ purchasing decisions. Although prior research on the effects of price changes on consumer reactions has provided insightful implications, little is known about the impact of price changes on the characteristics of OPRs. With the growing importance of OPRs as a key social recommendation system for potential consumers’ decision-making, it is important to understand the dynamics of OPRs around price changes. We select the Kindle 2 from Amazon.com as our focal product and conduct an exploratory case study. By analyzing 6,714 reviews on the Kindle 2, we examine how consumers respond to price decreases using OPRs. The results show that all four characteristics of OPRs (star-rating, review depth, positive emotion, and negative emotion) are significantly influenced by price decreases. Moreover, we found that the impacts of price decreases on OPRs’ characteristics are different between the first and the second attempts at price reduction. Interestingly, the number of reviews per day significantly soars immediately after the first price decrease, while there is no significant change in the number of reviews after the second price cut. We conclude the paper with a discussion of our findings

Clinical implications of correlation between peripheral eosinophil count and serum levels of IL-5 and tryptase in acute eosinophilic pneumonia

SummaryBackgroundThe peripheral eosinophil count (PEC) tends to increase during the course of acute eosinophilic pneumonia (AEP), and an initially elevated PEC is associated with milder disease. However, there is a lack of data regarding these phenomena and inflammatory process of AEP.MethodsWe prospectively evaluated serial changes in serum interleukin (IL)-5 levels and the correlation between the initial level of IL-5 and the PEC to investigate whether the initial PEC indicates a resolving state of inflammation. We also evaluated serum tryptase levels to investigate the possibility of involvement of mast cell activity in AEP.ResultsTwenty-one AEP patients were included, and all patients improved within 10 days after corticosteroid treatment. The median initial serum IL-5 level among all patients was 561.0 pg/mL, which decreased to zero at 10 days of follow-up (n = 15, P < 0.001). The median initial serum tryptase level (detectable in 20 of 21 patients) was 3.7 ng/mL and decreased to a median of 1.1 ng/mL at 10 days of follow-up (n = 15, P < 0.001). The initial serum IL-5 and C-reactive protein levels were positively correlated (P = 0.009, r = 0.556), and the initial serum IL-5 level was inversely correlated with the initial PEC (P = 0.004, r = −0.603).ConclusionsOur data suggest that IL-5 is an important cytokine involved in the recruitment of eosinophils from peripheral blood into the lungs, that an initially elevated PEC is associated with a resolving state of inflammation, and that mast cells are potentially involved in the inflammatory process of AEP