170 research outputs found

    Enhanced cardiac expression of two isoforms of matrix metalloproteinase-2 in experimental diabetes mellitus.

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    BackgroundDiabetic cardiomyopathy (DM CMP) is defined as cardiomyocyte damage and ventricular dysfunction directly associated with diabetes independent of concomitant coronary artery disease or hypertension. Matrix metalloproteinases (MMPs), especially MMP-2, have been reported to underlie the pathogenesis of DM CMP by increasing extracellular collagen content.PurposeWe hypothesized that two discrete MMP-2 isoforms (full length MMP-2, FL-MMP-2; N-terminal truncated MMP-2, NTT-MMP-2) are induced by high glucose stimulation in vitro and in an experimental diabetic heart model.MethodsRat cardiomyoblasts (H9C2 cells) were examined to determine whether high glucose can induce the expression of the two isoforms of MMP-2. For the in vivo study, we used the streptozotocin-induced DM mouse heart model and age-matched controls. The changes of each MMP-2 isoform expression in the diabetic mice hearts were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemical stains were conducted to identify the location and patterns of MMP-2 isoform expression. Echocardiography was performed to compare and analyze the changes in cardiac function induced by diabetes.ResultsQuantitative RT-PCR and immunofluorescence staining showed that the two MMP-2 isoforms were strongly induced by high glucose stimulation in H9C2 cells. Although no definite histologic features of diabetic cardiomyopathy were observed in diabetic mice hearts, left ventricular systolic dysfunction was determined by echocardiography. Quantitative RT-PCR and IHC staining showed this abnormal cardiac function was accompanied with the increases in the mRNA levels of the two isoforms of MMP-2 and related to intracellular localization.ConclusionTwo isoforms of MMP-2 were induced by high glucose stimulation in vitro and in a Type 1 DM mouse heart model. Further study is required to examine the role of these isoforms in DM CMP

    Optical Shaping of Plasma Cavity for Controlled Laser Wakefield Acceleration

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    Laser wakefield accelerators rely on relativistically moving micron-sized plasma cavities that provide extremely high electric field >100GV/m. Here, we demonstrate transverse shaping of the plasma cavity to produce controlled sub-GeV electron beams, adopting laser pulses with an axially rotatable ellipse-shaped focal spot. We showed the control capability on electron self-injection, charge, and transverse profile of the electron beam by rotating the focal spot. We observed that the effect of the elliptical focal spot was imprinted in the profiles of the electron beams and the electron energy increased, as compared to the case of a circular focal spot. We performed 3D particle-in-cell (PIC) simulations which reproduced the experimental results and revealed dynamics of a new asymmetric self-injection process. This simple scheme offers a novel control method on laser wakefield acceleration to produce tailored electron beams and x-rays for various applications.Comment: 5 pages, 5 figure

    Recent Trend in the Incidence of Premalignant and Malignant Skin Lesions in Korea between 1991 and 2006

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    We evaluated the recent trend in the incidence of premalignant and malignant skin lesions between 1991 and 2006. Among 571,057 newly registered dermatology out-patients from our 8 affiliated university hospitals, 2,598 were diagnosed with a premalignant (899, 0.16%) or malignant skin lesions (1,699, 0.30%). Of 899 premalignant cases, 71.2% were actinic keratosis (AK), and 24.6% were Bowen's disease. Of 1,699 malignant cases, 46.2% were basal cell carcinoma, followed by squamous cell carcinoma (19.1%) and melanoma (7.1%). This 16-yr survey was divided equally into two time periods to compare the incidence of premalignant and malignant skin lesions at different time settings. Between 1991 and 1998, the incidence of cutaneous premalignancy was 0.10% which doubled during 1999-2006. For cutaneous malignancy, the incidence was 0.25% during 1991-1998 and 0.34% in 1999-2006. Incidence of AK among the new outpatients was 0.07% in 1991-1998 which staggered up to 0.15% in 1999-2006. These findings show an increase of both premalignant and malignant skin lesions, AK in particular in the dermatology outpatient-based incidence

    Detection of sarcocystic infection in a wild rodent (Apodemus agrarius chejuensis) captured on Jeju island

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    Sarcocystis spp is a causative agent of sarcocystosis. They have a characteristic life cycle infecting both prey and predator. Sarcocystis can cause myositis, atrophy of the adjacent cells and abortion in cattle. In mice, sarcocystosis causes mild cellular reactions without clinical disease. Severe haemorrhage and abortion were also reported. For monitoring the disease in wild rodents of the Korean peninsula, we captured Apodemus agrarius chejuensis on Jeju island and examined the specimen histopathologically. Intramuscular cysts were found and diagnosed as Sarcocystis. Sarcocystic infection has been reported in worldwide. There have been many reported infections in cattle and pigs in Korea. To our knowledge, this is the first report of Sarcocystis in Apodemus agrarius chejuensis captured in Korea

    Electron energy increase in a laser wakefield accelerator using up-ramp plasma density profiles

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    The phase velocity of the wakefield of a laser wakefield accelerator can, theoretically, be manipulated by shaping the longitudinal plasma density profile, thus controlling the parameters of the generated electron beam. We present an experimental method where using a series of shaped longitudinal plasma density profiles we increased the mean electron peak energy more than 50%, from 175 +/- 1 MeV to 262 +/- 10 MeV and the maximum peak energy from 182 MeV to 363 MeV. The divergence follows closely the change of mean energy and decreases from 58.9 +/- 0.45 mrad to 12.6 +/- 1.2 mrad along the horizontal axis and from 35 +/- 0.3 mrad to 8.3 +/- 0.69 mrad along the vertical axis. Particle-in-cell simulations show that a ramp in a plasma density profile can affect the evolution of the wakefield, thus qualitatively confirming the experimental results. The presented method can increase the electron energy for a fixed laser power and at the same time offer an energy tunable source of electrons.© The Author(s) 201

    Risk factors for and clinical outcomes of carbapenem non-susceptible gram negative bacilli bacteremia in patients with acute myelogenous leukemia

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    Background Carbapenem is frequently used when gram negative bacilli (GNB) bacteremia is detected especially in neutropenic patients. Consequently, appropriate treatment could be delayed in GNB bacteremia cases involving organisms which are not susceptible to carbapenem (carba-NS), resulting in a poor clinical outcomes. Here, we explored risk factors for carba-NS GNB bacteremia and its clinical outcomes in patients with acute myelogenous leukemia (AML) that underwent chemotherapy. Methods We reviewed all GNB bacteremia cases that occurred during induction or consolidation chemotherapy, over a 15-year period, in a tertiary-care hospital. Results Among 489 GNB bacteremia cases from 324 patients, 45 (9.2%) were carba-NS and 444 (90.8%) were carbapenem susceptible GNB. Independent risk factors for carba-NS GNB bacteremia were: carbapenem use at bacteremia onset (adjusted odds ratio [aOR]: 91.2; 95% confidence interval [95%CI]: 29.3–284.1; P < 0.001); isolation of carbapenem-resistant Acinetobacter baumannii (aOR: 19.4, 95%CI: 3.4–112.5; P = 0.001) in the prior year; and days from chemotherapy to GNB bacteremia (aOR: 1.1 per day, 95%CI: 1.1–1.2; P < 0.001). Carba-NS bacteremia was independently associated with in-hospital mortality (aOR: 6.6, 95%CI: 3.0–14.8; P < 0.001). Conslusion Carba-NS organisms should be considered for antibiotic selection in AML patients having these risk factors
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