Catheter-based delivery of cells to the heart

Clinical trials have begun to assess the feasibility, safety, and efficacy of administering progenitor cells to the heart in order to repair or perhaps reverse the effects of myocardial ischemia and injury. In contrast to surgical-based injections, which are often coupled with coronary bypass surgery, catheter-based injections are less invasive and make it possible to evaluate cell products used as sole interventions. The two methods that have been tested in humans are injecting cells directly into the ventricular wall with catheter systems dedicated to that purpose and infusing cells into coronary arteries with standard balloon angioplasty catheters. The catheters described in this article have been shown in both animal and clinical studies to be effective in cell delivery and to be safe. They are well-designed and user-friendly devices, but require further investigation to identify means for optimizing cell retention and to address other limitations. Randomized, placebo-controlled trials utilizing catheters for cell implantation are under way, and others are soon to follow. The results of these studies will help to shape the direction of future investigations, both clinical and basic. The spectrum of cardiac diseases, the variety of catheters for cell delivery, and the wide array of progenitor cell types open up this young field to creative discoveries

From comparative to international genocide studies: the international production of genocide in 20th-century Europe

Genocide is widely seen as a phenomenon of domestic politics, which becomes of international significance because it offends against international law. Hence there are as yet inadequate International Relations analyses of the production of genocide. This article challenges the idea of the domestic genesis of genocide, and critiques the corresponding approach of ‘comparative genocide studies’ which is dominant in the field. It analyses the emergence of more fruitful ‘relational’ and ‘international’ approaches in critical genocide studies, while identifying the limitations of their accounts of the ‘international system’. As first steps towards an adequate international account, the article then explores questions of the international meaning and construction of genocidal relations, and of international relations as the context of genocide. It argues for a historical and sociological approach to the international relations of genocide, and examines 20th-century European genocide in this light. Arguing for a broader conception of this historical experience than is suggested by an exclusive focus on the Holocaust, the article offers an interpretation of genocide as increasingly endemic and systemic in international relations in the first half of the century. It concludes by arguing that this account offers a starting point, but not a model, for analyses of genocide in global international relations in the 21st centur

Inverse poroelasticity as a fundamental mechanism in biomechanics and mechanobiology

How soft tissues respond to mechanical load is essential to their biological function. Here, the authors discover that – contrary to predictions of poroelasticity – fluid mobility in collagenous tissues induces drastic volume decrease with tensile loading and pronounced chemo-mechanical coupling