Preparation of gelatin nanogel modified with fluoride anion and its ultrasonic triggered release characteristics / 药学学报

<p><b>AIM</b>To investigate the preparation, shape and ultrasound triggered release characteristics of gelatin nanogel modified with fluoride anion.</p><p><b>METHODS</b>Adriamycin gelatin nanogel modified with fluoride anion (ADM-FMNG) was prepared by co-precipitation with fluoride anion. The content and encapsulation rate of adriamycin were measured by HPLC method. The size and shape of ADM-FMNG were determined by electron microscope. The size and distribution of ADM-FDNG before and after sonication were measured by laser size analysis device.</p><p><b>RESULTS</b>The average diameter of ADM-FMNG was (46 +/- 12) nm. Adriamycin encapsulated rate and loading were 87.2% and 0.091 g x L(-1), respectively. 48.5% of adriamycin was released within 50 h while in vitro at 37 degrees C. Under the action of ultrasound that has the frequency of 20 kHz, 0.4 W x cm(-2) of power density and 7-8 min duration, 51. 5% of adriamycin in ADM-FMNG was released that was significantly higher than control group, the size of ADM-FMNG was changed from (46 +/- 12) nm to (1,212 +/- 35) nm and restored after ultrasound stopped for 3-4 min.</p><p><b>CONCLUSION</b>ADM-FDNG system has the sensitive ultrasound triggered release characteristics.</p>

Pulmonary functional MRI: an animal model study of oxygen-enhanced ventilation combined with Gd-DTPA-enhanced perfusion / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The assessment of regional pulmonary ventilation and perfusion is essential for the evaluation of a variety of lung disorders. Pulmonary ventilation MRI using inhaled oxygen as a contrast medium can be obtained with a clinical MR scanner, without additional equipment, and has been demonstrated to be a feasible means of assessing ventilation in animal models and some clinical patients. However, few studies have reported on MR ventilation-perfusion imaging. In this study, we evaluated the usefulness of oxygen-enhanced ventilation in combination with first-pass Gd-DTPA-enhanced perfusion MRI in a canine model of pulmonary embolism and airway obstruction.</p><p><b>METHODS</b>Peripheral pulmonary embolisms were produced in eight dogs by intravenous injection of gelfoam strips at the pulmonary segmental arterial level, and airway obstructions were created in five of the dogs by inserting a self-designed balloon catheter into a secondary bronchus. Oxygen-enhanced MR ventilation images were produced by subtracting images from before and after inhalation of pure oxygen. Pulmonary perfusion MR images were acquired with a dynamic three-dimensional fast gradient-echo sequence. MR ventilation and perfusion images were read and contrasted with results from general examinations of pathological anatomy, ventilation-perfusion scintigraphy, and pulmonary angiography.</p><p><b>RESULTS</b>Regions identified as having airway obstructions matched using both MR ventilation and perfusion imaging, but regions of pulmonary embolisms were mismatched. The area of airway obstruction defects was smaller using MR ventilation imagery than that using ventilation scintigraphy. Abnormal perfusion regions due to pulmonary embolisms were divided into defective regions and reduced regions based on the time course of signal intensity changes. In the diagnosis of pulmonary embolisms with the technique of ventilation and perfusion MRI, sensitivity and specificity were 75.0% and 98.1%, respectively, and the diagnostic results of this MRI technique were in agreement with the results of ventilation-perfusion scintigraphy and pulmonary angiography (K: 0.899, 0.743).</p><p><b>CONCLUSIONS</b>Oxygen-enhanced ventilation in combination with pulmonary perfusion MRI can be used to diagnose abnormalities of airways and blood vessels in the lungs, and can provide regional functional information with high spatial and temporal resolution. This method possesses great potential value for clinical applications.</p>