Efficacy of AiiM, an N-Acylhomoserine Lactonase, against Pseudomonas aeruginosa in a Mouse Model of Acute Pneumonia

Quorum sensing (QS) in Pseudomonas aeruginosa regulates the production of many virulence factors and plays an important role in the pathogenesis of P. aeruginosa infection. N-acyl homoserine lactones (AHL) are major QS signal molecules. Recently, a novel AHL-lactonase enzyme, AiiM, has been identified. The aim of this study was to evaluate the effect of AiiM on the virulence of P. aeruginosa in a mouse model of acute pneumonia. We developed a P. aeruginosa PAO1 strain harboring an AiiM-expressing plasmid. The production of several virulence factors by the AiiM-expressing strain was examined. Mice were intratracheally infected with an AiiM-expressing PAO1 strain. Lung histopathology, bacterial burden, and bronchoalveolar lavage (BAL) fluid were assessed at 24 h postinfection. AiiM expression in PAO1 reduced production of AHL-mediated virulence factors and attenuated cytotoxicity against human lung epithelial cells. In a mouse model of acute pneumonia, AiiM expression reduced lung injury and greatly improved the survival rates. The levels of proinflammatory cytokines and myeloperoxidase activity in BAL fluid were significantly lower in mice infected with AiiM-expressing PAO1. Thus, AiiM can strongly attenuate P. aeruginosa virulence in a mammalian model and is a potential candidate for use as a therapeutic agent against P. aeruginosa infection

Short-term strength adaptation in isometric training to volitional failure depends on initial specific tension in elbow flexors

We tested a hypothesis that individuals with low maximal voluntary isometric contraction relative to muscle cross-sectional area (MVC/mCSA) would have greater strength gain compared to those with high MVC/mCSA in an early stage from beginning of isometric training to volitional failure. Male adults (n = 24; 22.4 ± 2.5 years, 174.1 ± 6.5 cm, 75.8 ± 14.1 kg) conducted a 3-week isometric training to volitional failure (60-80% MVC, 2-3 times/week, 3 sets/session) in elbow joint flexion with 90° flexion of each arm. Based on the relationship between MVC and mCSA before the intervention, we assigned 16 arms to the higher group (HIGH), 14 to the lower group (LOW) and 18 to the mean group (MEAN). Before the intervention and at the beginning of every week, we measured MVC (myometer) and muscle thickness of anterior upper arm (ultrasound). The mCSA was derived from muscle thickness. The 3-week isometric training to volitional failure increased MVC in all groups, but the relative change in MVC through the intervention was higher in LOW than in HIGH and MEAN groups. The current findings of this study support the abovementioned hypothesis

Relationship between Carotid Intima-Media Thickness and the Center of Pressure Trajectories in the Randomly Selected Elderly Population

科学研究費補助金研究成果報告書研究種目: 基盤研究(C)研究期間: 2007～2008課題番号: 19500594研究代表者: 宮松 直美（滋賀医科大学・医学部・教授）研究分担者: 盛永 美保（滋賀医科大学・医学部・講師）研究分担者: 秦 朝子（滋賀医科大学・医学部・助教）研究分担者: 岡本 真優（滋賀医科大学・医学部・助教）研究分担者: 三宅 依子（滋賀医科大学・医学部・助教）連携研究者: 盛永 美保（滋賀医科大学・医学部・講師）連携研究者: 荻田 美穂子（滋賀医科大学・医学部・助教）連携研究者: 小河 望（滋賀医科大学・医学部・助手）連携研究者: 加藤 みのり（滋賀医科大学・医学部・助手）連携研究者: 門脇 崇（滋賀医科大学・医学部・助教）連携研究者: 上島 弘嗣（滋賀医科大学・医学部・教授