21 research outputs found

    Determination of Sulfonamides in Chicken Muscle by Pulsed Direct Current Electrospray Ionization Tandem Mass Spectrometry

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    A simple and rapid approach for the simultaneous detection of trace amounts of six sulfonamides in chicken muscle was developed using pulsed direct current electrospray ionization tandem mass spectrometry (pulsed-dc ESI-MS/MS). The pretreatment of chicken muscle samples consisted of two steps: acetonitrile extraction and <i>n</i>-hexane delipidation. Sulfonamides do not need to be derivatized or chromatographed prior to pulsed-dc ESI-MS/MS. The factors affecting the performance of pulsed-dc ESI-MS/MS were studied. Under optimum conditions, the quantitative performance of pulsed-dc ESI-MS/MS was validated according to European Union Decision 2002/657/EC, and the sensitivity of pulsed-dc ESI-MS/MS was 3 times higher than that of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The limits of detection obtained by pulsed-dc ESI-MS/MS were in the range of 0.07–0.11 μg/kg. The proposed method was simple, rapid, and sensitive, and was successfully used for quantitation and rapid screening of sulfonamides in real chicken muscle samples

    Role of differentiated CSCs (DCSCs) in myocardial functional recovery following I/R.

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    <p>A, Expression of Sca-1, CD29 and CD44 in DCSCs was determined by Flow cytometry assay. B, RT Real-time PCR analysis indicated transcription levels of cardiac specific transcription factors and genes in DCSCs. C, Western blot assay demonstrated increased expression of Gata4 and sarcomeric (SM) α-actin in DCSCs compared to un-induced CSCs. D, Expression of SM α-actin (green) and Gata4 (red) was observed in DCSCs by Immunofluoresence assay (Magnification 400X). Nucleus was stained with DAPI (blue). Myocardial functional recovery at end of reperfusion was represented as % of equilibration (Eq) in groups treated with vehicle, CSC and DCSC (E) or media control, CSC CM and DCSC CM (F). Mean ± SEM, n = 5–6/group, *p<0.01, **p<0.001 vs. Vehicle or Media C, #p<0.01, ##p<0.001 vs. CSC or CSC CM. CM: conditioned medium.</p

    The Akt pathway in CSC-induced cardioprotection following I/R.

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    <p>A, Western blot assay revealed myocardial Akt activation in groups of Vehicle, CSCs, media control and CSC CM after I/R. B, The use of AMD3100 in CSC CM or SDF-1 siRNA in CSCs did not change myocardial Akt activation. Shown are representative immunoblots of p-Akt and T-Akt (one lane/group), and densitometry data of p-Akt represented as % of T-Akt. C, Inhibition of the Akt signaling by LY294002 did not affect CSC-improved post-ischemic LVDP, +dP/dt and –dP/dt. Results are mean ± SEM, n = 4-6/group, *p<0.05, **p<0.01 vs. control or LY294002 alone at the corresponding time point.</p

    CSC-derived SDF-1 in the attenuation of cellular injury.

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    <p>A, Remaining LDH levels in cardiac tissue were determined after I/R. B, Western blot analysis indicated cleaved caspase-3 levels after I/R. Shown is representative immunoblots in each groups (one lane/group). Bar graph represents relative levels of Caspase-3 P20 (% of GAPDH). C, Myocardial hydrogen peroxide (H2O2) production was analyzed after I/R. A–C: Mean ± SEM, N = 4–5/group, *p<0.05, **p<0.01 vs. Vehicle. D, Cardiomyocyte (H9c2) viability and LDH levels in supernatant were determined after 24-hr of hypoxia in groups of vehicle and CSC CM with or without AMD3100. Mean ± SEM, N = 3, *p<0.05 vs. vehicle.</p

    Determination of dominant paracrine factor(s) in CSCs.

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    <p>A, Cytokine antibody array was performed in conditioned medium (CM) from CSCs and DCSCs. Each number represented the fold increase of cytokine expression compared to the negative control (medium). B, CSC- and DCSC-secreted SDF-1 was determined in supernatants by ELISA. C, The SDF-1 expression in CSCs and cardiomyocytes was analyzed in cell lysates using ELISA. Mean ± SEM, N = 3–6/groups, ***p<0.001 vs. CSC. UD: Undetectable.</p

    CSC-derived SDF-1 in mediating acute protection following I/R.

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    <p>A, Changes of LVDP and +/− dP/dt following I/R in groups of media control and CSC CM with or without AMD3100, an inhibitor of the SDF-1 receptor. B, Myocardial functional recovery at end of reperfusion was shown as % of Eq (equilibration). Mean ± SEM, n = 5–6/group, *p<0.05, **p<0.01, ***p<0.001. CM: conditioned medium.</p

    Myocardial STAT3 in CSC-mediated acute cardioprotection following I/R.

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    <p>A, Myocardial activation of STAT3 was determined in groups of Vehicle, CSCs, media control and CSC CM after I/R by Western blot assay. B, AMD3100 or SDF-1 siRNA neutralized CSC-induced STAT3 activation compared to their counterparts. Representative immunoblots of p-STAT3 and T-STAT3 were shown (one lane/group) and bar graph represents relative levels of p-STAT3/T-STAT3 ( %) in A and B. C, Stattic abolished CSC-mediated acute protection as demonstrate by unimproved LVDP and +/− dP/dt following I/R. D. Remaining LDH in myocardial tissue after I/R. E. Cardiac caspase-3 levels were determined in hearts treated with vehicle, stattic and CSC+stattic after I/R by Western blot. Shown are representative immunoblots (2 lanes/group). Results are Mean ± SEM, N = 4–5/group, *p<0.05 vs. vehicle or media control.</p

    Identification of cardiac stem cell (CSC) characteristics.

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    <p>A, Flow cytometry assay indicated expression of cell surface markers in CSCs. B, Expression of cell surface markers in mesenchymal stem cells (MSCs). C, RT Real-time PCR data showed mRNA levels of cardiac specific transcription factors in CSCs, MSCs and cardiomyocytes (isolated from adult mouse heart as a positive control). Mean ± SEM, n = 3 individual experiments. UD: Undetectable.</p
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