Can pulsed ultrasound increase tissue damage during ischemia? A study of the effects of ultrasound on infarcted and non-infarcted myocardium in anesthetized pigs

BACKGROUND: The same mechanisms by which ultrasound enhances thrombolysis are described in connection with non-beneficial effects of ultrasound. The present safety study was therefore designed to explore effects of beneficial ultrasound characteristics on the infarcted and non-infarcted myocardium. METHODS: In an open chest porcine model (n = 17), myocardial infarction was induced by ligating a coronary diagonal branch. Pulsed ultrasound of frequency 1 MHz and intensity 0.1 W/cm(2 )(I(SATA)) was applied during one hour to both infarcted and non-infarcted myocardial tissue. These ultrasound characteristics are similar to those used in studies of ultrasound enhanced thrombolysis. Using blinded assessment technique, myocardial damage was rated according to histopathological criteria. RESULTS: Infarcted myocardium exhibited a significant increase in damage score compared to non-infarcted myocardium: 6.2 ± 2.0 vs. 4.3 ± 1.5 (mean ± standard deviation), (p = 0.004). In the infarcted myocardium, ultrasound exposure yielded a further significant increase of damage scores: 8.1 ± 1.7 vs. 6.2 ± 2.0 (p = 0.027). CONCLUSION: Our results suggest an instantaneous additive effect on the ischemic damage in myocardial tissue when exposed to ultrasound of stated characteristics. The ultimate damage degree remains to be clarified

Pulling and Gouging: The Sadrist Line’s Adaptable and Evolving Repertoire of Contention

The symbolic infiltration of Baghdad’s Green Zone by thousands of protesters in April 2016 was a peak moment in Iraq’s contentious politics and demonstrated the mobilising capacity of the Sadrist Line, the civil society constituency of the Sadrist network. The protesters’ grievances—poor government service delivery, corruption, insecurity, and the ethnosectarian quota system that is criticised for entrenching these problems—had been expressed through contentious action since 2003, yet the events in April 2016 were unprecedented. The Sadrist Line is the largest and most powerful participant in an instrumental coalition that includes diverse civil society groups. This chapter conceptualises the Sadrist Line as a tolerated opposition group, which, in collaboration with its coalition, deploys an adaptable and evolving repertoire of contention to test the boundaries of toleration, make claims on the state, and portray the Sadrist Line as a credible, nonviolent participant in Iraqi civil society