1,581 research outputs found

    Snapshots for intra- and inter-ocular differences at retinal proteins levels

    Get PDF
    We attempted to study the intra- and inter-animal variations of protein expressions in chick retina using two-dimensional electrophoresis (2-DE). The posterior retinas of 10 day-old chicks were harvested. The proteins were extracted and 2-DE protein profiles between two eyes of the same individual and among different animals were compared and analysed using Melanie gel analysis software. Computerised Melanie gel analysis showed a high similarity of 83.1 ± 2.1% (mean ± SEM, n=3) between the protein profiles of right and left retinas from the same animal. However, this percentage dropped to 64.1 ± 3.1% (Mean ± SEM, n=3) when comparing between different animal samples. We have shown that there were good similarities in intra-animal comparison but poor in inter-animal comparison. We have documented the caveat in comparing the protein profiles between different animals where apparent differentially display protein could actually be a false positive signal. The finding highlighted the potential usefulness of the proteomic approach in basic eye research where comparison between control and experimental tissues could be carried out in the same animal, rather than using different animals

    Activation of Insulin-Like Growth Factor II Receptor Induces Mitochondrial-Dependent Apoptosis through G alpha q and Downstream Calcineurin Signaling in Myocardial Cells

    Get PDF
    [[abstract]]In previous studies, we have found that IGF-II and IGF-II receptor (IGF-IIR) dose dependently correlated with the progression of pathological hypertrophy after complete abdominal aorta ligation, which may play a critical role in angiotensin II-induced cardiomyocyte apoptosis. However, the detail mechanisms of IGF-IIR in the regulation of cell apoptosis in response to IGF-II remain unclear. By using IGF-IR short hairpin RNA to inhibit IGF-IR expression and using Leu27 IGF-II analog to activate specifically the IGF-IIR, we investigated the role of IGF-II/IGF-IIR activation and its downstream signaling. Our results revealed that IGF-II synergistically increased the cell apoptosis induced by suppressing of IGF-IR in neonatal rat ventricular myocytes. After binding of Leu27IGF-II, IGF-IIR became associated with alpha-q polypeptide, acted like a protein-coupled receptor to activate calcineurin, led to the translocation of Bad into mitochondria and release of cytochrome c into cytoplasm, and contributed to mitochondrial-dependent apoptosis in neonatal rat ventricular myocytes. Furthermore, inhibition of IGF-IIR, alpha-q polypeptide, or calcineurin by RNA interference could block the Leu27IGF-II-induced cell apoptosis. Together, this study provides a new insight into the effects of the IGF-IIR and its downstream signaling in myocardial apoptosis. Suppression of IGF-IIR signaling pathways may be a good strategy for both the protection against myocardial cell apoptosis and the prevention of heart failure progression. (Endocrinology 150: 2723-2731, 2009

    IGF-II/mannose-6-phosphate receptor signaling induced cell hypertrophy and atrial natriuretic peptide/BNP expression via G alpha q interaction and protein kinase C-alpha/CaMKII activation in H9c2 cardiomyoblast cells

    Get PDF
    [[abstract]]The role played by IGF-II in signal transduction through the IGF-II/mannose-6-phosphate receptor (IGF2R) in heart tissue has been poorly understood. In our previous studies, we detected an increased expression of IGF-II and IGF2K in cardiomyocytes that had undergone pathological hypertrophy. We hypothesized that after binding with IGF-II, IGF2K may trigger intracellular signaling cascades involved in the progression of pathologically cardiac hypertrophy. In this study, we used immunohistochemical analysis of the human cardiovascular tissue array to detect expression of IGF2K. In Our study of H9c2 cardiomyoblast cell cultures, we used the rhodamine phalloidin staining, to measure the cell hypertrophy and western blot to measure the expression of cardiac hypertrophy markets atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in cells treated with IGF-II. We found that a significant association between IMP, overexpression and myocardial infarction. The treatment of H9c2 cardiomyoblast cells with IGF-II not only induced cell hypertrophy but also increased the protein level of ANP and BNP. Using Leu27IGF-II, an analog of IGF-II which interacts selectively with the IGF2R to specifically activate IGF2R signaling cascades, we found that binding of Leu271GF-II to IGF2R), led to all increase in the phosphorylation of protein Kinase C (PKC)-alpha and calcium/calmodulin-dependent protein kinase II (CaMKII) in a G alpha q-dependent manner. By the inhibition of PKC-alpha/CaMKII activity, we found that IGF-II and Leu271GF-II-induced cell hypertrophy and upregulation of ANP and BNP were significantly suppressed. Taken together, this study provides a new insight into the effects of the IGF2R and its downstream signaling in cardiac hypertrophy. The suppression of IGF2R signaling pathways may be a good strategy to prevent the progression of pathological hypertrophy

    Using Chinese Version of MYMOP in Chinese Medicine Evaluation: Validity, Responsiveness and Minimally Important Change

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Measure Yourself Medical Outcome Profile (MYMOP) is a patient generated outcome instrument applicable in the evaluation of both allopathic and complementary medicine treatment. This study aims to adapt MYMOP into Chinese, and to assess its validity, responsiveness and minimally important change values in a sample of patients using Chinese medicine (CM) services.</p> <p>Methods</p> <p>A Chinese version of MYMOP (CMYMOP) is developed by forward-backward-forward translation strategy, expert panel assessment and pilot testing amongst patients. 272 patients aged 18 or above with subjective symptoms in the past 2 weeks were recruited at a CM clinic, and were invited to complete a set of questionnaire containing CMYMOP and SF-36. Follow ups were performed at 2<sup>nd </sup>and 4<sup>th </sup>week after consultation, using the same set of questionnaire plus a global rating of change question. Criterion validity of CMYMOP was assessed by its correlation with SF-36 at baseline, and responsiveness was evaluated by calculating the Cohen effect size (ES) of change at two follow ups. Minimally important difference (MID) values were estimated via anchor based method, while minimally detectable difference (MDC) figures were calculated by distribution based method.</p> <p>Results</p> <p>Criterion validity of CMYMOP was demonstrated by negative correlation between CMYMOP Profile scores and all SF-36 domain and summary scores at baseline. For responsiveness between baseline and 4<sup>th </sup>week follow up, ES of CMYMOP Symptom 1, Activity and Profile reached the moderate change threshold (ES>0.5), while Symptom 2 and Wellbeing reached the weak change threshold (ES>0.2). None of the SF-36 scores reached the moderate change threshold, implying CMYMOP's stronger responsiveness in CM setting. At 2<sup>nd </sup>week follow up, MID values for Symptom 1, Symptom 2, Wellbeing and Profile items were 0.894, 0.580, 0.263 and 0.516 respectively. For Activity item, MDC figure of 0.808 was adopted to estimate MID.</p> <p>Conclusions</p> <p>The findings support the validity and responsiveness of CMYMOP for capturing patient centred clinical changes within 2 weeks in a CM clinical setting. Further researches are warranted (1) to estimate Activity item MID, (2) to assess the test-retest reliability of CMYMOP, and (3) to perform further MID evaluation using multiple, item specific anchor questions.</p

    Negative group delay for Dirac particles traveling through a potential well

    Full text link
    The properties of group delay for Dirac particles traveling through a potential well are investigated. A necessary condition is put forward for the group delay to be negative. It is shown that this negative group delay is closely related to its anomalous dependence on the width of the potential well. In order to demonstrate the validity of stationary-phase approach, numerical simulations are made for Gaussian-shaped temporal wave packets. A restriction to the potential-well's width is obtained that is necessary for the wave packet to remain distortionless in the travelling. Numerical comparison shows that the relativistic group delay is larger than its corresponding non-relativistic one.Comment: 10 pages, 5 figure

    Ripple Texturing of Suspended Graphene Atomic Membranes

    Full text link
    Graphene is the nature's thinnest elastic membrane, with exceptional mechanical and electrical properties. We report the direct observation and creation of one-dimensional (1D) and 2D periodic ripples in suspended graphene sheets, using spontaneously and thermally induced longitudinal strains on patterned substrates, with control over their orientations and wavelengths. We also provide the first measurement of graphene's thermal expansion coefficient, which is anomalously large and negative, ~ -7x10^-6 K^-1 at 300K. Our work enables novel strain-based engineering of graphene devices.Comment: 15 pages, 4 figure

    Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating

    Get PDF
    Our study employed large-eddy simulation (LES) based on a one-equation subgrid-scale model to investigate the flow field and pollutant dispersion characteristics inside urban street canyons. Unstable thermal stratification was produced by heating the ground of the street canyon. Using the Boussinesq approximation, thermal buoyancy forces were taken into account in both the Navier–Stokes equations and the transport equation for subgrid-scale turbulent kinetic energy (TKE). The LESs were validated against experimental data obtained in wind-tunnel studies before the model was applied to study the detailed turbulence, temperature, and pollutant dispersion characteristics in the street canyon of aspect ratio 1. The effects of different Richardson numbers (Ri) were investigated. The ground heating significantly enhanced mean flow, turbulence, and pollutant flux inside the street canyon, but weakened the shear at the roof level. The mean flow was observed to be no longer isolated from the free stream and fresh air could be entrained into the street canyon at the roof-level leeward corner. Weighed against higher temperature, the ground heating facilitated pollutant removal from the street canyon.Singapore-MIT Alliance for Research and Technology. Center for Environmental Sensing and Monitorin

    Phenomenological Consequences of sub-leading Terms in See-Saw Formulas

    Full text link
    Several aspects of next-to-leading (NLO) order corrections to see-saw formulas are discussed and phenomenologically relevant situations are identified. We generalize the formalism to calculate the NLO terms developed for the type I see-saw to variants like the inverse, double or linear see-saw, i.e., to cases in which more than two mass scales are present. In the standard type I case with very heavy fermion singlets the sub-leading terms are negligible. However, effects in the percent regime are possible when sub-matrices of the complete neutral fermion mass matrix obey a moderate hierarchy, e.g. weak scale and TeV scale. Examples are cancellations of large terms leading to small neutrino masses, or inverse see-saw scenarios. We furthermore identify situations in which no NLO corrections to certain observables arise, namely for mu-tau symmetry and cases with a vanishing neutrino mass. Finally, we emphasize that the unavoidable unitarity violation in see-saw scenarios with extra fermions can be calculated with the formalism in a straightforward manner.Comment: 22 pages, matches published versio

    Valoración de la función contráctil del ventrículo derecho por deformación en escala de grises bidimensional en una población con hipertensión pulmonar

    Get PDF
    Quantification of right ventricular function continues to evolve, even though his assessment is difficult due to the complex geometry of this cardiac chamber.Objectiveto characterize right ventricular function by calculating the strain, the longitudinal strain rate of the right ventricular free wall and the ejection fraction and volumes of the ventricle through assessment of the strain by two-dimensional speckle tracking, and to compare it with tricuspid annulus peak systolic excursion (TAPSE) in patients with pulmonary hypertension and in healthy population.Methodobservational descriptive studyResultsWe included 120 patients, of whom 80 suffered from pulmonary hypertension and 40 were healthy. The overall strain of the right ventricular free wall was significantly lower in the group with pulmonary hypertension compared to healthy subjects (-20.5 ± 6 vs. -25 ± 4.5; p <0.001); regional strain showed similar behavior. The overall longitudinal strain rate showed no significant differences between groups. We found a significant correlation between TAPSE and ejection fraction of the right ventricle (r = 0.49; p <0.001) and an inverse correlation between TAPSE and global longitudinal strain of the right ventricle free wall (r = -0.41; p <0.001).Conclusionsthe assessment of regional right ventricular function by two dimensional speckle tracking can be a useful tool for assessing right ventricular systolic function in patients with pulmonary arterial hypertension
    corecore