130 research outputs found

    Impact of Short-Term Training Camp on Aortic Blood Pressure in Collegiate Endurance Runners

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    To investigate the influence of short-term vigorous endurance training on aortic blood pressure (BP), pulse wave analysis was performed in 36 highly trained elite collegiate endurance runners before and after a 7-day intense training camp. Subjects participated three training sessions per day, which mainly consisted of long distance running and sprint training to reach the daily target distance of 26 km. After the camp, they were divided into two groups based on whether the target training was achieved. Aortic systolic BP, pulse pressure, and tension-time index (TTI, a surrogate index of the myocardial oxygen demand) were significantly elevated after the camp in the accomplished group but not in the unaccomplished group, whereas the brachial BP remained unchanged in both groups. The average daily training distance was significantly correlated with the changes in aortic systolic BP (r = 0.608, p = 0.0002), pulse pressure (r = 0.415, p = 0.016), and TTI (r = 0.438, p = 0.011). These results suggest that aortic BP is affected by a short-term vigorous training camp even in highly trained elite endurance athletes presumably due to a greater training volume compared to usual

    Esophageal granular cell tumor successfully resected by endoscopic submucosal dissection

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    Granular cell tumors of the esophagus are rare neoplasms and their diagnosis is mainly based on histopathologic examination of endoscopic biopsies. With the development of endoscopic techniques, there has been a marked increase in local treatment modalities for early esophageal neoplasms. In this case report, we describe the removal of a granular cell tumor by the endoscopic submucosal dissection technique, and briefly discuss the literature on clinicopathologic aspects and management of granular cell tumors

    Role of Organic Cation Transporter 1, OCT1 in the Pharmacokinetics and Toxicity of cis-Diammine(pyridine)chloroplatinum(II) and Oxaliplatin in Mice

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    PurposeThe goal of this study was to test the hypothesis that by controlling intracellular uptake, organic cation transporter 1, Oct1 is a key determinant of the disposition and toxicity of cis-diammine(pyridine)chloroplatinum(II)(CDPCP) and oxaliplatin.MethodsPharmacokinetics, tissue accumulation and toxicity of CDPCP and oxaliplatin were compared between Oct1-/- and wild-type mice.ResultsAfter intravenous administration, hepatic and intestinal accumulation of CDPCP was 2.7-fold and 3.9-fold greater in Oct1 wild-type mice (p < 0.001). Deletion of Oct1 resulted in a significantly decreased clearance (0.444 ± 0.0391 ml/min*kg versus 0.649 ± 0.0807 ml/min*kg in wild-type mice, p < 0.05) and volume distribution (1.90 ± 0.161 L/kg versus 3.37 ± 0.196 L/kg in wild-type mice, p < 0.001). Moreover, Oct1 deletion resulted in more severe off-target toxicities in CDPCP-treated mice. Histologic examination of the liver and measurements of liver function indicated that the level of hepatic toxicity was mild and reversible, but was more apparent in the wild-type mice. In contrast, the effect of Oct1 on the pharmacokinetics and toxicity of oxaliplatin in the mice was minimal.ConclusionsOur study suggests that Oct1 plays an important role in the pharmacokinetics, tissue distribution and toxicity of CDPCP, but not oxaliplatin

    Chromosome 7 and 19 Trisomy in Cultured Human Neural Progenitor Cells

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    BACKGROUND:Stem cell expansion and differentiation is the foundation of emerging cell therapy technologies. The potential applications of human neural progenitor cells (hNPCs) are wide ranging, but a normal cytogenetic profile is important to avoid the risk of tumor formation in clinical trials. FDA approved clinical trials are being planned and conducted for hNPC transplantation into the brain or spinal cord for various neurodegenerative disorders. Although human embryonic stem cells (hESCs) are known to show recurrent chromosomal abnormalities involving 12 and 17, no studies have revealed chromosomal abnormalities in cultured hNPCs. Therefore, we investigated frequently occurring chromosomal abnormalities in 21 independent fetal-derived hNPC lines and the possible mechanisms triggering such aberrations. METHODS AND FINDINGS:While most hNPC lines were karyotypically normal, G-band karyotyping and fluorescent in situ hybridization (FISH) analyses revealed the emergence of trisomy 7 (hNPC(+7)) and trisomy 19 (hNPC(+19)), in 24% and 5% of the lines, respectively. Once detected, subsequent passaging revealed emerging dominance of trisomy hNPCs. DNA microarray and immunoblotting analyses demonstrate epidermal growth factor receptor (EGFR) overexpression in hNPC(+7) and hNPC(+19) cells. We observed greater levels of telomerase (hTERT), increased proliferation (Ki67), survival (TUNEL), and neurogenesis (beta(III)-tubulin) in hNPC(+7) and hNPC(+19), using respective immunocytochemical markers. However, the trisomy lines underwent replicative senescence after 50-60 population doublings and never showed neoplastic changes. Although hNPC(+7) and hNPC(+19) survived better after xenotransplantation into the rat striatum, they did not form malignant tumors. Finally, EGF deprivation triggered a selection of trisomy 7 cells in a diploid hNPC line. CONCLUSIONS:We report that hNPCs are susceptible to accumulation of chromosome 7 and 19 trisomy in long-term cell culture. These results suggest that micro-environmental cues are powerful factors in the selection of specific hNPC aneuploidies, with trisomy of chromosome 7 being the most common. Given that a number of stem cell based clinical trials are being conducted or planned in USA and a recent report in PLoS Medicine showing the dangers of grafting an inordinate number of cells, these data substantiate the need for careful cytogenetic evaluation of hNPCs (fetal or hESC-derived) before their use in clinical or basic science applications

    Involvement of PPAR-γ in the neuroprotective and anti-inflammatory effects of angiotensin type 1 receptor inhibition: effects of the receptor antagonist telmisartan and receptor deletion in a mouse MPTP model of Parkinson's disease

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    <p>Abstract</p> <p>Background</p> <p>Several recent studies have shown that angiotensin type 1 receptor (AT1) antagonists such as candesartan inhibit the microglial inflammatory response and dopaminergic cell loss in animal models of Parkinson's disease. However, the mechanisms involved in the neuroprotective and anti-inflammatory effects of AT1 blockers in the brain have not been clarified. A number of studies have reported that AT1 blockers activate peroxisome proliferator-activated receptor gamma (PPAR γ). PPAR-γ activation inhibits inflammation, and may be responsible for neuroprotective effects, independently of AT1 blocking actions.</p> <p>Methods</p> <p>We have investigated whether oral treatment with telmisartan (the most potent PPAR-γ activator among AT1 blockers) provides neuroprotection against dopaminergic cell death and neuroinflammation, and the possible role of PPAR-γ activation in any such neuroprotection. We used a mouse model of parkinsonism induced by the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and co-administration of the PPAR-γ antagonist GW9662 to study the role of PPAR-γ activation. In addition, we used AT1a-null mice lesioned with MPTP to study whether deletion of AT1 in the absence of any pharmacological effect of AT1 blockers provides neuroprotection, and investigated whether PPAR-γ activation may also be involved in any such effect of AT1 deletion by co-administration of the PPAR-γ antagonist GW9662.</p> <p>Results</p> <p>We observed that telmisartan protects mouse dopaminergic neurons and inhibits the microglial response induced by administration of MPTP. The protective effects of telmisartan on dopaminergic cell death and microglial activation were inhibited by co-administration of GW9662. Dopaminergic cell death and microglial activation were significantly lower in AT1a-null mice treated with MPTP than in mice not subjected to AT1a deletion. Interestingly, the protective effects of AT1 deletion were also inhibited by co-administration of GW9662.</p> <p>Conclusion</p> <p>The results suggest that telmisartan provides effective neuroprotection against dopaminergic cell death and that the neuroprotective effect is mediated by PPAR-γ activation. However, the results in AT1-deficient mice show that blockage of AT1, unrelated to the pharmacological properties of AT1 blockers, also protects against dopaminergic cell death and neuroinflammation. Furthermore, the results show that PPAR-γ activation is involved in the anti-inflammatory and neuroprotective effects of AT1 deletion.</p

    MicroRNA Dysregulation in the Spinal Cord following Traumatic Injury

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    Spinal cord injury (SCI) triggers a multitude of pathophysiological events that are tightly regulated by the expression levels of specific genes. Recent studies suggest that changes in gene expression following neural injury can result from the dysregulation of microRNAs, short non-coding RNA molecules that repress the translation of target mRNA. To understand the mechanisms underlying gene alterations following SCI, we analyzed the microRNA expression patterns at different time points following rat spinal cord injury

    Crystal structure and biochemical analyses reveal Beclin 1 as a novel membrane binding protein

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    The Beclin 1 gene is a haplo-insufficient tumor suppressor and plays an essential role in autophagy. However, the molecular mechanism by which Beclin 1 functions remains largely unknown. Here we report the crystal structure of the evolutionarily conserved domain (ECD) of Beclin 1 at 1.6 Å resolution. Beclin 1 ECD exhibits a previously unreported fold, with three structural repeats arranged symmetrically around a central axis. Beclin 1 ECD defines a novel class of membrane-binding domain, with a strong preference for lipid membrane enriched with cardiolipin. The tip of a surface loop in Beclin 1 ECD, comprising three aromatic amino acids, acts as a hydrophobic finger to associate with lipid membrane, consequently resulting in the deformation of membrane and liposomes. Mutation of these aromatic residues rendered Beclin 1 unable to stably associate with lipid membrane in vitro and unable to fully rescue autophagy in Beclin 1-knockdown cells in vivo. These observations form an important framework for deciphering the biological functions of Beclin 1

    Basement membrane components are key players in specialized extracellular matrices

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    More than three decades ago, basement membranes (BMs) were described as membrane-like structures capable of isolating a cell from and connecting a cell to its environment. Since this time, it has been revealed that BMs are specialized extracellular matrices (sECMs) with unique components that support important functions including differentiation, proliferation, migration, and chemotaxis of cells during development. The composition of these sECM is as unique as the tissues to which they are localized, opening the possibility that such matrices can fulfill distinct functions. Changes in BM composition play significant roles in facilitating the development of various diseases. Furthermore, tissues have to provide sECM for their stem cells during development and for their adult life. Here, we briefly review the latest research on these unique sECM and their components with a special emphasis on embryonic and adult stem cells and their niches
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