Yun-Chao Chen

Tongji Hospital, Wu-han-shih, Hubei, China

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Publications (7)11.83 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: It is a globally challenging problem to differentially diagnose biliary atresia (BA) from other disease processes causing infantile cholestatic jaundice. The high-frequency ultrasonography (HUS) yields much improved spatial resolution and therefore, might show better image in BA diagnostic examination. The present study was to evaluate the HUS on the diagnosis of BA in infants with jaundice. Fifty-one infants with neonatal jaundice were scanned with ultrasonography. Images included gallbladder, bile duct, right hepatic artery (RHA), portal vein (PV) and triangular cord (TC) sign, magnetic resonance imaging and additionally, laboratory tests and histopathology reports were assessed. Twenty-three BA and 28 non-BA cases were confirmed. The sensitivity, specificity, and accuracy of HUS were 91.3%, 92.9%, and 92.2%, respectively. All of these indices were significantly higher than those of conventional ultrasonography (P<0.01) and MR cholangiopancreatography (P<0.05). The HUS features, included a positive TC sign, an increased RHA diameter and RHA-diameter to portal-vein-diameter ratio (RHA/PV) and abnormal gallbladder, were important in the diagnosis of BA. HUS provided better imaging of BA and should be considered as a primary modality in the differential diagnosis of infantile jaundice.
    Hepatobiliary & pancreatic diseases international: HBPD INT 08/2013; 12(4):415-22. · 1.26 Impact Factor
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    ABSTRACT: PURPOSE To investigate whether ultrasound and PEI can enhance plasmid DNA transfection in HepG2 cell synergistically or not. METHOD AND MATERIALS Two kinds of PEI, which one used specifically in gene delivery(sPEI)and the other used just as general industrial materials(iPEI), were used. The toxicity of PEI was determined by trypan blue dye exclusion. The PEIs were incubated with the plasmid DNA to prepare cationic compounds (PEI/DNA), which were added into HepG2 cell with or without ultrasound irradiation. After 24 hours, the transfection efficiency was assessed by fluorescence microscope and FACS. Ultrasound parameters: 1 MHz, 1W/cm2, 20s, 20% duty cycle. RESULTS Ultrasound could induce gene delivery in HepG2 cell. PEI displayed high toxic to cell and the concentration of 0.001% was used in gene delivery, which induced about 70% cell survival rate. The two PEI compounds significantly enhanced the plasmid DNA gene delivery in HepG2 cell(P<0.01) and the transfection rates of the iPEI and sPEI were 15.42±4.71 and 12.27±3.58 respectively. Even though the difference of the two PEI was not significant(P>0.05), their transfection rates were higher than that of the ultrasound group(P<0.01). On the other hand, PEI with ultrasonic irradiation group showed a lower transfection rate compared with the PEI groups(P<0.01) CONCLUSION PEI and ultrasound irradiation all can promote plasmid DNA transfection in vitro respectively but they do not show synergistically. CLINICAL RELEVANCE/APPLICATION PEI and ultrasound irradiation all can promote plasmid DNA transfection in vitro respectively but they do not show synergistically.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 11/2011
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    ABSTRACT: Pluronic block copolymers, a kind of non-ionic surfactant, also known as poloxamers, and ultrasound-targeted microbubble destruction have been respectively investigated as vectors for gene delivery in vitro and in vivo. However, they are limited for clinical application due to the relatively low transfer efficiency of each individual vector. In the present study, we explored if the combination of P85, a pluronic block copolymer, Optison, a microbubble contrast agent and ultrasound enhances the transfection of plasmid DNA in vivo using mouse skeletal muscle models. Plasmid encoding green fluorescent protein (GFP) was respectively conjugated with 0.05%P85, 10%Optison, or 0.05%P85 plus 10%Optison, and injected into mouse tibialis anterior (TA) muscles with or without ultrasound irradiation (1 MHz, 1 W/cm(2), 2 min and 20% duty cycle). Mice were sacrificed 1 week after injection. The TA muscles were collected and cryo-sectioned into a series of 7 μm slices. To assess the efficiency of plasmid DNA transfection, tissue sections were counterstained with DAPI and scored by counting the number of GFP-positive fibers. Meanwhile the area of damaged muscles was measured based on the tissues stained with hematoxylin and eosin. Both P85 and Optison significantly enhanced the delivery of plasmid DNA in mouse TA skeletal muscles (P<0.01 and P<0.05 respectively, compared to saline control). In combination with Ultrasound irradiation, P85 (P<0.01, compared to P85 alone) but not Optison (P>0.05, compared to Optison alone) exerted a more pronounced effect on the transfection efficiency. Furthermore P85-induced gene delivery was higher than that by Optison regardless of the presence of ultrasound (P<0.01). The highest transfection efficiency was observed when P85, Optison and ultrasound irradiation were administrated together (P<0.01, compared to any other treatment in this study). The area of damaged muscles was enlarged by ultrasound irradiation in the presence of Optison microbubbles (P<0.01, compared to those groups without ultrasound irradiation). These results suggest that P85, microbubbles and ultrasound irradiation synergistically enhance plasmid DNA delivery in mouse skeletal muscles in vivo.
    Ultrasonics Sonochemistry 03/2011; 18(2):513-9. · 3.52 Impact Factor
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    ABSTRACT: The pluronic block copolymers are able to enhance the ultrasound-induced gene delivery in vitro. In the present study, the effects of pluronics on the efficiency of gene transfer into skeletal muscle in vivo under sonoporation were investigated. Plasmid DNA encoding green fluorescent protein (GFP) in combination with three different pluronics, F127, L61, and P85, was injected into the tibialis anterior (TA) muscle of mice with and without adjunct ultrasound (1 MHz, 3 W/cm(2) 1 min, 20% duty cycle). Mice were killed 1 week after injection. The TA muscles were removed and snap frozen immediately in isopentane cooled by liquid nitrogen and sections of 7 μm thick were cut. Transfection efficiency was assessed by counting the number of GFP-positive fibers under fluorescence microscopy, and tissue damage by hematoxylin and eosin staining. The results suggested that all three pluronics significantly enhanced transgene expression in skeletal muscle (P < 0.01), especially the P85 showed significantly higher efficiency than the other two pluronics (P < 0.05). Ultrasound synergistically enhanced the gene delivery efficiency with P85 (P < 0.01), but was unable to do so with F127 and L61 groups. In short, P85 displays significantly synergistic effect with ultrasound for enhancing plasmid DNA transduction in skeletal muscle of mice in vivo.
    Cell biochemistry and biophysics 01/2011; 60(3):267-73. · 3.34 Impact Factor
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    ABSTRACT: Pluronics have been investigated as vectors for drug and gene delivery in vitro and in vivo and were demonstrated to have high efficiency for gene transfer in vivo. However, they alone do not enhance gene transfer in vitro. We examined three pluronics, F127, L61 and P85, for their effects on ultrasound (US)-mediated gene transfer in three cell lines, 3T3-MDEI, C2C12 and CHO. The polymers showed differential effects on cell viability and transfection efficiency in a dose-dependent manner. All the polymers were unable to facilitate gene transfer when used alone, but enhanced US-mediated gene transfer significantly at concentrations around the critical micelle concentration in the three cell lines. F127 showed no significant toxicity at any concentration and protected the cells against US-mediated damage at a high concentration. L61 decreased cell viability significantly in a dose-dependent manner, whereas P85 showed mild toxicity when its concentration was at or above 0.05%.
    Ultrasound in Medicine & Biology 02/2006; 32(1):131-7. · 2.46 Impact Factor
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    ABSTRACT: PURPOSE It has been known for over a decade that ultrasound can aid in the delivery of molecules and genes into cells through a process of cell membrane permeabilisation (sonoporation). The underlying mechanisms however remain unclear. Evidence from electron microscopic images has suggested a role for relatively long lasting pores: (Tachibana et al. 1999). We have studied the duration of the permeabilisation using a fluorescent macromolecule tag. METHOD AND MATERIALS Chinese Hamster Ovary cells (CHO) were exposed by ultrasound (2W/cm2 for 10 seconds, 20% duty cycle, 1MHz). We added equivalent quantities of the fluorescent macromolecule FITC Dextran (66k Da) (A) prior to insonification (B) within the first second of insonification (C) at medium time points (2s, 20s, 60s, 10min, 20mins) (D) at 1hour and later after insonification. The level of uptake was assessed using flow cytometry. RESULTS High uptake (85%) was seen when the FITC Dextran was present prior to insonification. Much lower values were seen when it was added after insonification from 2s to 20 mins (all values under 20%). This occurred even when added within the first second that ultrasound was applied (uptake of 10%). A monotonic progression in uptake with the delay from exposure was seen, with declining uptake with longer delays. Cell viability remained moderate at all exposure levels. Interestingly however, after a recovery period of 1 hour or more after insonification, the internalization of the macromolecules was comparable to the positive control. CONCLUSIONS These data suggest that the sonoporation effect is a non-linear process. The difference between conditions (A) and (B) suggests a dramatic alteration of permeabilisation may occur within the first second. The temporal changes over the medium time frame under conditions (C) may relate to slow resealing. The reasons why higher uptake was seen at later time points over an hour (conditions D) is unclear, and is the subject of further investigations. These observations may be useful in planning the use of sonoporation both with and without microbubbles for gene therapy and drug delivery in guiding the timing of ultrasound exposure.
    Radiological Society of North America 2004 Scientific Assembly and Annual Meeting; 12/2004
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    ABSTRACT: To assess the value of color Doppler ultrasonography in monitoring normal orthotopic liver transplantation and postoperative complications. Forty-one patients after orthotopic liver transplantation were examined by using color Doppler flow imaging to observe the hepatic blood flow and change of ultrasonography of the hepatic parenchyma and bile duct. The measured indexes included maximum blood flow velocity, time-average blood flow velocity (TAV), resistance index (RI) and diameter of the bile duct. Among 41 patients, 17 (41.5%) suffered from liver transplant rejection. Of the 17 patients, 13 (76.4%) showed decrease of TAV of the portal vein, 15 (88.25%) low-amplitude single-phase serrated wave or negative biphasic wave of the hepatic vein, 9 (52.9%) increased hepatic arterial RI, and 5 (29.4%) slightly dilated bile duct. Sonography showed disappearance of the hepatic artery blood flow around the portal vein in 5 (12.2%) of the 41 patients with hepatic artery thrombosis in the postoperative period. Slight dilatation of the intrahepatic bile duct was found in 3 (7.3%) of the 41 patients in the early postoperational period and it normalized within 2 weeks. Ultrasonography of 20 patients (48.8%) revealed a visible dilatation of the intrahepatic bile duct, which was worsening gradually. The causes of bile duct dilatation included biliary stricture in 2 patients (10%), stone in 15 patients (75%) and others in 3 patients (15%). Color Doppler ultrasonography is valuable for monitoring normal liver transplantation and postoperative complications.
    Hepatobiliary & pancreatic diseases international: HBPD INT 03/2003; 2(1):54-8. · 1.26 Impact Factor

Publication Stats

20 Citations
11.83 Total Impact Points

Institutions

  • 2003–2013
    • Tongji Hospital
      Wu-han-shih, Hubei, China
  • 2006
    • Imperial College London
      • Department of Imaging Sciences
      London, ENG, United Kingdom