55 research outputs found

    GROUND REACTION FORCE OF THE FIRST TRANSITION DURING ACCELERATED SPRINTING: A PILOT STUDY

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    This study aimed to show changes in step-to-step ground reaction forces around the first transition during maximal accelerated sprinting with a typical sprinter. One male sprinter performed five 60-m maximal accelerated sprints, during which ground reaction forces through 50 m were recorded with 54 force platforms. There were sudden shifts of values for step frequency, support time, vertical impulse and braking and propulsive mean forces at around the 5th step as the first sprint transition. These sudden shift of variables support the concept of sprint transition during acceleration phase. The findings of this study would be interesting for the future study of locomotor control and practically useful for considering the strategy of accelerated sprinting

    CONTRIBUTION OF FORWARD AND VERTICAL IMPULSES DURING MAXIMAL 5OM SPRINTING TO THE MAXIMUM RUNNING VELOCITY IN SPRINTERS

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    The present study developed a 50 m-forceplate system and examined relationships between the impulse calculated from ground reaction force (GRF) from start to 50m and the maximum running velocity (Vfmax). Thirty five male sprinters performed maximal sprint on the system, using starting block. The forward and vertical components of impulses (IMPf and IMPv. respectively) were computed far each support phase by integrating the GRF. The highest correlation coefficients for both IMPf(~0.736)a nd IMPv(r=-0.729) were found at the distance of 10 m from the start. These results indlcate the ability to keep lMPv low and lMPf high seems to be important for achieving greater Vfmax, notably in the initial stage of acceleration phase

    RELATIONSHIP OF BASE-RUNNING PERFORMANCE WITH RUNNING DIRECTION AND ITS CHANGE

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    The purpose of this study was to clarify whether the running direction and its change affect the base-running performance. Thirty-five male baseball players performed 54.86 m (180 ft.) straight-line sprinting and distance-matched base-running, during which two dimensional positions of players were recorded with B Y Sports Tracking System. The results of this study revealed that the total base-running performance was probably affected by the running performance of the later running phase. In addition, smaller direction change before the first base and larger direction change after the first base maybe responsible for better performance in the entire base-running through better performance in the later section. These results would be useful for players and coaches who attempt to improve base-running performance

    ACCURACY IN DETERMINING KINETIC PARAMETERS WITH FORCE PLATES EMBEDDED UNDER SOIL-FILLED BASEBALL MOUND

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    We developed a force measurement system embedded in a soil-filled mound for measuring ground reaction forces (GRF) acting on baseball pitchers and examined the accuracy of determining the point of force application (PFA) and kinetic parameters computed from GRF. Three 1.0 x 0.9 m2 force platforms were placed on the concrete foundation of an indoor sports facility and three bays were fixed onto the aluminum plates of the force plateorms. In each tray, clay-blocks were laid tightly and a mixture of red sand and volcanic-ash was used to make a smooth surface layer. The mean absolute error was 6.0 f 4.0 mm in determining PFA, less than 15.5 Ns (5% of the true value) in determining linear impulse. These results suggest that the present method is valid for measuring the PFA and GRF acting on the pitcher's legs for analyzing kinetics of pitching performances

    Eosinophil Cationic Protein Shows Survival Effect on H9c2 Cardiac Myoblast Cells with Enhanced Phosphorylation of ERK and Akt/GSK-3β under Oxidative Stress

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    Eosinophil cationic protein (ECP) is well known as a cationic protein contained in the basic granules of activated eosinophils. Recent studies have reported that ECP exhibits novel activities on various types of cells, including rat neonatal cardiomyocytes. Here we evaluated the effects of ECP on rat cardiac myoblast H9c2 cells. Our results showed that ECP enhanced the survival of the cells, in part by promoting the ERK and Akt/GSK-3β signaling pathways. ECP attenuated the cytotoxic effects of H2O2 on H9c2 cells as well as the production of reactive oxygen species, the number of apoptotic cells and caspase 3/7 activity in the cells. In conclusion, ECP activated the ERK and Akt/GSK-3β pathways, resulting in anti-oxidative effects on H9c2 cells that attenuated apoptosis

    Antitumor effects of α-bisabolol against pancreatic cancer.

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    In the present study, we investigated whether α-bisabolol, a sesquiterpene alcohol present in essential oils derived from a variety of plants, has antitumor effects against pancreatic cancer. α-Bisabolol induced a decrease in cell proliferation and viability in pancreatic cancer cell lines (KLM1, KP4, Panc1, MIA Paca2), but not in pancreatic epithelial cells (ACBRI515). α-Bisabolol treatment induced apoptosis and suppressed Akt activation in pancreatic cancer cell lines. Furthermore, α-bisabolol treatment induced the overexpression of early growth response-1 (EGR1), whereas EGR1 siRNA decreased the α-bisabolol-induced cell death of KLM1 cells. Tumor growth in both subcutaneous and peritoneal xenograft nude mouse models was significantly inhibited by intragastric administration of 1000 mg/kg of α-bisabolol, once a week for three weeks. The results indicate that α-bisabolol could be a novel therapeutic option for the treatment of pancreatic cancer

    Analysis of Factors Associated With Radiation-Induced Bronchiolitis Obliterans Organizing Pneumonia Syndrome After Breast-Conserving Therapy

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    Purpose: To evaluate factors associated with radiation-induced bronchiolitis obliterans organizing pneumonia (BOOP) syndrome after breast-conserving therapy. Methods and materials: A total of 702 women with breast cancer who received radiotherapy after breast-conserving surgery at seven institutions between July 1995 and December 2006 were analyzed. In all patients, the whole breast was irradiated with two tangential photon beams. The criteria used for the diagnosis of radiation-induced BOOP syndrome were as follows: (1) radiotherapy to the breast within 12 months, (2) general and/or respiratory symptoms lasting for >or=2 weeks, (3) radiographs showing lung infiltration outside the radiation port, and (4) no evidence of a specific cause. Results: Radiation-induced BOOP syndrome was seen in 16 patients (2.3%). Eleven patients (68.8%) were administered steroids. The duration of steroid administration ranged from 1 week to 3.7 years (median, 1.1 years). Multivariate analysis revealed that age (>or=50 years; odds ratio [OR] 8.88; 95% confidence interval [CI] 1.16-67.76; p = 0.04) and concurrent endocrine therapy (OR 3.05; 95% CI 1.09-8.54; p = 0.03) were significantly associated with BOOP syndrome. Of the 161 patients whose age was >or=50 years and who received concurrent endocrine therapy, 10 (6.2%) developed BOOP syndrome. Conclusions: Age (>or=50 years) and concurrent endocrine therapy can promote the development of radiation-induced BOOP syndrome after breast-conserving therapy. Physicians should carefully follow patients who received breast-conserving therapy, especially those who are older than 50 years and received concurrent endocrine therapy during radiotherapy

    Efficient Drug Delivery of Paclitaxel Glycoside: A Novel Solubility Gradient Encapsulation into Liposomes Coupled with Immunoliposomes Preparation

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    Although the encapsulation of paclitaxel into liposomes has been extensively studied, its significant hydrophobic and uncharged character has generated substantial difficulties concerning its efficient encapsulation into the inner water core of liposomes. We found that a more hydrophilic paclitaxel molecule, 7-glucosyloxyacetylpaclitaxel, retained tubulin polymerization stabilization activity. The hydrophilic nature of 7-glucosyloxyacetylpaclitaxel allowed its efficient encapsulation into the inner water core of liposomes, which was successfully accomplished using a remote loading method with a solubility gradient between 40% ethylene glycol and Cremophor EL/ethanol in PBS. Trastuzumab was then conjugated onto the surface of liposomes as immunoliposomes to selectively target human epidermal growth factor receptor-2 (HER2)-overexpressing cancer cells. In vitro cytotoxicity assays revealed that the immunoliposomes enhanced the toxicity of 7-glucosyloxyacetylpaclitaxel in HER2-overexpressing cancer cells and showed more rapid suppression of cell growth. The immunoliposomes strongly inhibited the tumor growth of HT-29 cells xenografted in nude mice. Notably, mice survived when treated with the immunoliposomes formulation, even when administered at a lethal dose of 7-glucosyloxyacetylpaclitaxel in vivo. This data successfully demonstrates immunoliposomes as a promising candidate for the efficient delivery of paclitaxel glycoside
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