Ultrasound-mediated microbubble destruction increases capillary permeability in rat skeletal muscles / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of ultrasound mediated microbubble destruction on capillary permeability in rat skeletal muscles.</p><p><b>METHODS</b>Eighteen SD rats were randomized into 3 groups, namely the Evans blue (EB) group, EB+ultrasound (E+U) group and EB+microbubble+ultrasound (U+E+M) group with corresponding treatments, using EB injected into the carotid artery as the indicator for capillary permeability. The microbubbles were injected through the carotid artery with fixed ultrasound parameters. The spillover of EB was estimated under fluorescence microscope according to the visual staining scores. The contents of EB in the skeletal muscles were calculated according to the standard curve and spectrophotometry.</p><p><b>RESULTS</b>EB spillover was observed around the capillaries in E+U+M group, which had a significantly higher visual score than EB group and E+U group (0 and 0-1, respectively, P<0.05). The EB content was 51.57-/+3.89 microg/g in E+U+M group, also significantly higher than those in EB group (28.99-/+4.67 microg/g) and E+U group (30.99-/+4.11 microg/g) (P<0.05).</p><p><b>CONCLUSION</b>Exposure to both ultrasound and microbubble contrast agents results in increased capillary permeability of rat skeletal muscles, which might be an important mechanisms for gene delivery enhancement by ultrasound contrast agents.</p>

Therapeutic effect of recombinant human brain natriuretic peptide for treatment of decompensated heart failure: comparison with nitroglycerin / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the therapeutic effect of recombinant human brain natriuretic peptide (rhBNP) and nitroglycerin on acute decompensated heart failure (ADHF).</p><p><b>METHODS</b>Fifty ADHF patients were randomly divided into rhBNP group and nitroglycerin group. In all the patients, dyspnea and global clinical status were assessed before and at 30 min, 6 h and 24 h after drug administration, and the volume of fluid intake and urine along with hemodynamic parameters was recorded 24 h after drug administration. In the nitroglycerin group, the patients received an initial nitroglycerin dose of 5 microg/min, with subsequent dose increment of 5 microg/min every 3 to 5 min; the dose was adjusted individually according to the hemodynamics of the patients. The patients in rhBNP group were given rhBNP at the initial dose of 1.5 microg/kg by with an intravenous bolus injection followed by infusion at the rate of 0.0075 microg.kg(-1).min(-1) for 72 h.</p><p><b>RESULTS</b>At 30 min and 6 h after drug administration, the patients in the rhBNP group showed significant greater improvement of dyspnea (P=0.042 and 0.019) and global clinical status (P=0.018 and 0.044) than those in the nitroglycerin group, but 24 h after drug administration, no significant difference was noted between the two groups (P=0.192 and 0.179). Twenty-four hours after drug administration, the mean urine volume was significantly greater in rhBNP group than in nitroglycerin group (1513.8-/+242.9 vs 1341.2-/+239.7 ml, P=0.015), and the ejection fraction increased and pulmonary arterial pressure and systolic blood pressure decreased at greater amplitude in the former group (P=0.001,0.000 and 0.002, respectively). At 72 h, the numbers of premature ventricular contraction and couplets premature beats and onset of paroxysmal ventricular tachycardia were significantly reduced in rhBNP group as compared with the nitroglycerin group (P=0, 0.001 and 0.002, respectively).</p><p><b>CONCLUSION</b>RhBNP promotes urine excretion, decreases pulmonary arterial pressure and increases left ventricular ejection fraction to improve dyspnea and global clinical status and reduce the onset of ventricular arrhythmia in ADHF patients.</p>