Chronic vascular constrictions and measurements of renal function in conscious rats

Although a tremendous amount of physiologic information has been gained from experiments on anesthetized animals, there is often the question to what extent anesthesia itself, as well as the losses and replacement of fluid that accompany surgical preparations, might have influenced the function being studied. This possible pitfall may apply especially to studies on the kidney because the renal circulation is so exquisitely sensitive to anesthetic agents and changes in fluid balance. Chronic preparations in dogs have been [1] and continue to be used [2] successfully. But the far lesser expense of rats, as well as their common use in physiologic experiments, points up the desirability of a successful chronic preparation in this species. Renal clearances have been performed previously on unanesthetized rats [3, 4], but the methods have not been generally adopted.We here describe a method that can measure renal clearances and extraction of PAH accurately and repeatedly in the same conscious rat over a period of weeks. For our own purposes [5] we also needed a method for constricting blood vessels. The design and construction of a suitable cuff for this purpose, likewise usable in unanesthetized rats, also form part of this report

Zur Ästhetik und Poetik des Spinnennetzes

The imagery of spider webs has always been characterized by a fundamental ambivalence. Disgust and admiration, transience and eternal cycle, demonization and attribution to divine genius are combined in this image much like nature and technology or woman and man. After a description of the cultural-historical roots of this dialectic relationship the paper addresses the aesthetic of the cobweb and analyses on that basis the narrative formations of the metaphor. The myth of Arachne in Ovid's "Metamorphoses" serves here as a reference for a reading of three modern texts: Hanns Heinz Ewer’ "Die Spinne", Ken Kesey's "One flew over the cuckoo's nest" and Manuel Puig's "El beso de la mujer araña". I argue that spider webs illustrate asymmetrical and gendered power structures, in which negatively connotated spiders represent femininity. Furthermore, in literary texts spider webs seems to symbolize the eternal provisional arrangement that characterizes the life of modern figures. That may be considered as an updating of the tension between immanence and transcendence which existed since Arachne

Aldosterone Antagonists in Monotherapy Are Protective against Streptozotocin-Induced Diabetic Nephropathy in Rats

Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) are the standard clinical therapy of diabetic nephropathy (DN), while aldosterone antagonists are only used as adjuncts. Previously in experimental DN we showed that Na/K ATPase (NKA) is mislocated and angiotensin II leads to superimposed renal progression. Here we investigated the monotherapeutic effect of aldosterone blockers on the progression of DN and renal NKA alteration in comparison to ACEi and ARBs. Streptozotocin-diabetic rats developing DN were treated with aldosterone antagonists; ACEi and ARB. Renal function, morphology, protein level and tubular localization of NKA were analyzed. To evaluate the effect of high glucose per se; HK-2 proximal tubular cells were cultured in normal or high concentration of glucose and treated with the same agents. Aldosterone antagonists were the most effective in ameliorating functional and structural kidney damage and they normalized diabetes induced bradycardia and weight loss. Aldosterone blockers also prevented hyperglycemia and diabetes induced increase in NKA protein level and enzyme mislocation. A monotherapy with aldosterone antagonists might be as, or more effective than ACEi or ARBs in the prevention of STZ-induced DN. Furthermore the alteration of the NKA could represent a novel pathophysiological feature of DN and might serve as an additional target of aldosterone blockers