Objective:To explore the feasibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing the microcirculatory perfusion of skeletal muscle in rabbit limbs in the early stage after high-voltage electric burns.Methods:This study was an experimental study. Thirty-two male big ear white rabbits aged 6-8 months were assigned into electric burn group of 20 rabbits with high-voltage electric burns in the right lower limb and control group of 12 rabbits with sham injury in the right lower limb using the random number table method. At 0.5, 24.0, 48.0, and 72.0 h post injury, the lower limbs of rabbits in the two groups underwent axial fast spin echo T1-weighted imaging, fast spin echo T2-weighted imaging, and DCE-MRI examination. A reference region-based hemodynamic model was applied to obtain the blood perfusion parameters of skeletal muscle in the injured limbs, including the volume transfer constant K trans value and rate constant K ep value. The skeletal muscle tissue from the electric burn group of rabbits at 0.5, 24.0, 48.0, and 72.0 h post injury and the control group of rabbits at 0.5 h post injury was harvested for immunohistochemical staining to observe the microvascular changes and calculate the microvascular density (MVD). The correlation between the K trans and K ep values and the MVD of skeletal muscle tissue in electric burn group of rabbits at 0.5-72.0 h post injury was analyzed. The number of samples was 5 in the electric burn group, and the number of samples was 3 in the control burn group. Results:From 0.5-72.0 h post injury, the K trans and K ep values in skeletal muscle tissue of electric burn group of rabbits exhibited the trends of increase first and decrease then, both of which reached peak values at 24.0 h post injury. The K trans values at 0.5, 24.0, 48.0, and 72.0 h post injury (with t values of -15.77, -14.91, -40.35, and -40.25, respectively, P<0.05) and the K ep values at 0.5, 24.0, and 48.0 h post injury (with t values of -5.39, -6.82, and -6.83, respectively, P<0.05) in skeletal muscle tissue in electric burn group of rabbits were significantly higher than those in control group. The MVD in skeletal muscle tissue in control group of rabbits at 0.5 h post injury and in electric burn group of rabbits at 0.5, 24.0, 48.0, and 72.0 h post injury was (24.7±3.5), (21.8±2.2), (40.8±9.1), (16.4±2.4), and (9.8±0.8) per mm2, respectively. The MVD in skeletal muscle tissue in electric burn group of rabbits at 24.0 h post injury was significantly higher than that in control group at 0.5 h post injury ( t=2.89, P<0.05), and the MVD in skeletal muscle tissue at 48.0 and 72.0 h post injury was significantly lower than that in control group at 0.5 h post injury (with t values of 4.01 and 9.52, respectively, P<0.05). The K trans and K ep values of skeletal muscle tissue in rabbits in electric burn group were significantly positively correlated with microvascular density at 0.5 to 72.0 h post injury (with both r values of 0.95, P<0.05). Conclusions:The quantitative perfusion parameters K trans and K ep values of DCE-MRI can effectively reflect the microcirculatory perfusion changes of skeletal muscle in rabbit limbs in the early stage after high-voltage electric burns.

Objective:To explore the feasibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing the microcirculatory perfusion of skeletal muscle in rabbit limbs in the early stage after high-voltage electric burns.Methods:This study was an experimental study. Thirty-two male big ear white rabbits aged 6-8 months were assigned into electric burn group of 20 rabbits with high-voltage electric burns in the right lower limb and control group of 12 rabbits with sham injury in the right lower limb using the random number table method. At 0.5, 24.0, 48.0, and 72.0 h post injury, the lower limbs of rabbits in the two groups underwent axial fast spin echo T1-weighted imaging, fast spin echo T2-weighted imaging, and DCE-MRI examination. A reference region-based hemodynamic model was applied to obtain the blood perfusion parameters of skeletal muscle in the injured limbs, including the volume transfer constant K trans value and rate constant K ep value. The skeletal muscle tissue from the electric burn group of rabbits at 0.5, 24.0, 48.0, and 72.0 h post injury and the control group of rabbits at 0.5 h post injury was harvested for immunohistochemical staining to observe the microvascular changes and calculate the microvascular density (MVD). The correlation between the K trans and K ep values and the MVD of skeletal muscle tissue in electric burn group of rabbits at 0.5-72.0 h post injury was analyzed. The number of samples was 5 in the electric burn group, and the number of samples was 3 in the control burn group. Results:From 0.5-72.0 h post injury, the K trans and K ep values in skeletal muscle tissue of electric burn group of rabbits exhibited the trends of increase first and decrease then, both of which reached peak values at 24.0 h post injury. The K trans values at 0.5, 24.0, 48.0, and 72.0 h post injury (with t values of -15.77, -14.91, -40.35, and -40.25, respectively, P<0.05) and the K ep values at 0.5, 24.0, and 48.0 h post injury (with t values of -5.39, -6.82, and -6.83, respectively, P<0.05) in skeletal muscle tissue in electric burn group of rabbits were significantly higher than those in control group. The MVD in skeletal muscle tissue in control group of rabbits at 0.5 h post injury and in electric burn group of rabbits at 0.5, 24.0, 48.0, and 72.0 h post injury was (24.7±3.5), (21.8±2.2), (40.8±9.1), (16.4±2.4), and (9.8±0.8) per mm2, respectively. The MVD in skeletal muscle tissue in electric burn group of rabbits at 24.0 h post injury was significantly higher than that in control group at 0.5 h post injury ( t=2.89, P<0.05), and the MVD in skeletal muscle tissue at 48.0 and 72.0 h post injury was significantly lower than that in control group at 0.5 h post injury (with t values of 4.01 and 9.52, respectively, P<0.05). The K trans and K ep values of skeletal muscle tissue in rabbits in electric burn group were significantly positively correlated with microvascular density at 0.5 to 72.0 h post injury (with both r values of 0.95, P<0.05). Conclusions:The quantitative perfusion parameters K trans and K ep values of DCE-MRI can effectively reflect the microcirculatory perfusion changes of skeletal muscle in rabbit limbs in the early stage after high-voltage electric burns.

OBJECTIVEClone of sucrose synthase of Dendribium officinale and expression analysis, to provide the theory basis for research the relationship between polysaccharide synthesis of D. officinale and sucrose synthase activity.

METHODAccording to homologous sequence of sucrose synthase gene on GenBank, application the technology of RT-PCR and RACE, clone the full length of D. officinale. Target gene amplified with T vector was transformed into competent E. coli. BL21, IPTG induced expression, SDS-PAGE analysis.

RESULTA full length cDNA encoding sucrose synthase was isolated from the D. officinale, named DOSS1, the GenBank accession number is HQ856835, the cDNA is 2781 bp in length containing an open reading frame of 2424 bp encoding 807 amino acids with a predicted molecular mass of 92.3 x 10(3), the deduced amino acid sequence of D. officinale sucrose synthase shares 95% identity with Mokara yellow (AF530568); shares 90% identity with Oncidium goldiana (AF530567); shares more than 80% with other monocotyledonous plants.

CONCLUSIONCloned the sucrose synthase gene and induced an obvious band successfully.

3' Untranslated Regions ; genetics ; 5' Untranslated Regions ; genetics ; Cloning, Molecular ; Dendrobium ; enzymology ; genetics ; metabolism ; Escherichia coli ; genetics ; Gene Expression Regulation, Plant ; Glucosyltransferases ; genetics ; metabolism ; Phylogeny ; Polysaccharides ; biosynthesis