Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although clinical trials of stimulation of angiogenesis by transfection of angiogenic growth factors using naked plasmid DNA or adenoviral vector have been successful, there are still unresolved problems for human gene therapy such as low transfection efficiency and safety. From this viewpoint, it is necessary to develop safe and efficient novel nonviral gene transfer methods. As therapeutic ultrasound induces cell membrane permeabilization, ultrasound irradiation might increase the transfection efficiency of naked plasmid DNA into skeletal muscle. Thus, we examined the transfection efficiency of naked plasmid DNA using ultrasound irradiation with echo contrast microbubble (Optison) in vitro and in vivo experiments. First, we examined the feasibility of ultrasound-mediated transfection of naked plasmid DNA into skeletal muscle cells. Luciferase plasmid mixed with or without Optison was transfected into cultured human skeletal muscle cells using ultrasound (1 MHz; 0.4 W(2)) for 30 s. Interestingly, luciferase activity was markedly increased in cells treated with Optison, while little luciferase activity could be detected without Optison (P < 0.01). Electron microscopy demonstrated the transient formation of holes (less than 5 microM) in the cell surface, which could possibly explain the rapid migration of the transgene into the cells. Next, we studied the in vivo transfection efficiency of naked plasmid DNA using ultrasound with Optison into skeletal muscle. Two days after transfection, luciferase activity in skeletal muscle transfected with Optison using ultrasound was significantly increased about 10-fold as compared with plasmid alone. Successful transfection was also confirmed by beta-galactosidase staining. Finally, we examined the feasibility of therapeutic angiogenesis using naked hepatocyte growth factor (HGF) plasmid in a rabbit ischemia model using the ultrasound-Optison method. Five weeks after transfection, the angiographic score and the number of capillary density in rabbits transfected with Optison using ultrasound was significantly increased as compared with HGF plasmid alone (P < 0.01), accompanied by a significant increase in blood flow and blood pressure ratio (P < 0.01). Overall, the ultrasound transfection method with Optison enhanced the transfection efficiency of naked plasmid DNA in vivo as well as in vitro. Transfection of HGF plasmid by the ultrasound-Optison method could be useful for safe clinical gene therapy to treat peripheral arterial disease without a viral vector system.
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PMID:Development of safe and efficient novel nonviral gene transfer using ultrasound: enhancement of transfection efficiency of naked plasmid DNA in skeletal muscle. 1196 Mar 13

This study was aimed at determining if physiotherapy ultrasound (US) affected the fragile and leaky angiogenic blood vessels in a tumor. In 22 C3HV/HeN mice, a subcutaneous melanoma (K1735(22)) was insonated (1, 2 or 3 min) with continuous 1-MHz low-intensity (spatial-average temporal-average = 2.28 W cm(-2)), physiotherapy US. Contrast-enhanced (0.1 mL Optison) power Doppler US observations were made and histogram analyses of the images were performed. Before insonation, all but 7% of the tumor was perfused. The avascular area in tumors receiving 3-min treatment increased to 82% (p < 0.001). A linear regression analysis showed that each min of insonation led to a 25% reduction in tumor vascularity; the antivascular activity persisted for 24 h. Histology demonstrated disruption of vascular walls and tumor cell death in areas of vascular congestion and thrombosis. Physiotherapy US particularly targeted the vascular structures, and the effects on tumor cells appeared to be secondary to the resultant ischemia.
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PMID:The antivascular action of physiotherapy ultrasound on murine tumors. 1622 44

Focused ultrasound offers a method to disrupt the blood-brain barrier (BBB) noninvasively and reversibly at targeted locations. The purpose of this study was to test the safety of this method by searching for ischemia and apoptosis in areas with BBB disruption induced by pulsed ultrasound in the presence of preformed gas bubbles and by looking for delayed effects up to one month after sonication. Pulsed ultrasound exposures (sonications) were performed in the brains of 24 rabbits under monitoring by magnetic resonance imaging (MRI) (ultrasound: frequency = 1.63 MHz, burst length = 100 ms, PRF = 1 Hz, duration = 20 s, pressure amplitude 0.7 to 1.0 MPa). Before sonication, an ultrasound contrast agent (Optison, GE Healthcare, Milwaukee, WI, USA) was injected IV. BBB disruption was confirmed with contrast-enhanced MR images. Whole brain histologic examination was performed using haematoxylin and eosin staining for general histology, vanadium acid fuchsin-toluidine blue staining for ischemic neurons and TUNEL staining for apoptosis. The main effects observed were tiny regions of extravasated red blood cells scattered around the sonicated locations, indicating affected capillaries. Despite these vasculature effects, only a few cells in some of the sonicated areas showed evidence for apoptosis or ischemia. No ischemic or apoptotic regions were detected that would indicate a compromised blood supply was induced by the sonications. No delayed effects were observed either by MRI or histology up to 4 wk after sonication. Ultrasound-induced BBB disruption is possible without inducing substantial vascular damage that would result in ischemic or apoptotic death to neurons. These findings indicate that this method is safe for targeted drug delivery, at least when compared with the currently available invasive methods.
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PMID:MRI-guided targeted blood-brain barrier disruption with focused ultrasound: histological findings in rabbits. 1628 30

Histologic effects of focused ultrasound (FUS) exposures combined with an ultrasound contrast agent (Optison) were investigated to examine whether the lesions were dominated by apoptosis or necrosis. The rabbit brains (n = 17) were sonicated (1.5 MHz, peak rarefactional pressure amplitude: 1.4 to 8.8 MPa) after Optison was injected intravenously (IV). MRI and light microscopy were used to examine tissue effects. To detect apoptosis, TUNEL staining based on labeling of DNA strand breaks was used. The average number of apoptotic and necrotic cells in 300 x 220 microm microscopic fields were counted in 18 representative lesions. Lesions in the rabbit brains were created at lowered acoustic power levels when FUS was combined with Optison. In histology, the lesions exhibited red blood cell extravasations and destruction of blood vessels. At 4 h after sonication, the lesions lost many cells, and the remaining cells exhibited both necrotic and apoptotic features. Overall, apoptosis dominated; there were, on average, 32.3 +/- 13.2 apoptotic cells per microscopic field compared with only 5.1 +/- 3.4 necrotic cells per field. In conclusion, FUS combined with Optison could produce lesions that are dominated by apoptosis, presumably induced primarily via ischemia after cavitation-produced damage to the brain vasculature.
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PMID:Induction of apoptosis in vivo in the rabbit brain with focused ultrasound and Optison. 1716 4