A new clinical method for the assessment of penile endothelial function using the flow mediated dilation with plethysmography technique

PURPOSE: Penile endothelial function (EnF) is 1 of the major factors involved in the pathophysiology of erectile dysfunction. EnF assessment could offer crucial information on the etiology and degree of severity of cavernosal vascular pathology. In the present study we propose a new technique for the evaluation of penile EnF and test its applicability using strain gauge plethysmography. MATERIALS AND METHODS: A total of 23 healthy subjects (13 younger and 10 older than 40 years) with no history of erectile dysfunction were studied. The flow mediated dilation technique was applied to the arm and penis in both age groups for the assessment of EnF. Baseline blood flow and the sequential flow recordings after rapid cessation of 5 minutes of ischemia were obtained in both organs. RESULTS: Baseline flow in the penis was significantly higher (approximately 3-fold) than that in the forearm and was not affected by age in either organ. Both measures of penile EnF, ie area under the flow-time curve (AUC) and maximal flow obtained after ischemia were significantly lower in the older group compared to the younger group (p <0.01 and p <0.02, respectively). Individual penile AUC and maximal flow were significantly correlated with age (r = 0.55, p <0.01 and r = 0.50, p <0.02, respectively). Finally a positive, significant correlation existed between penile and forearm AUC (p <0.05, r = 0.48). CONCLUSIONS: The implementation of the flow mediated dilation technique using mercury strain gauge plethysmography is simple and applicable for the assessment of penile EnF. Endothelial function parameters in the penis were found to correlate with those in the forearm, thus support for the validity of the technique is given. Further strength for the validity of this procedure in the penis comes from the comparison between the forearm and penis, and the relation to subject age.     

The metabolism of glycosaminoglycans is impaired in prion diseases

It is well established that the conversion of PrP(C) to PrP(Sc) is the key event in prion disease biology. In addition, several lines of evidence suggest that glycosaminoglycans (GAGs) and in particular heparan sulfate (HS) may play a role in the PrP(C) to PrP(Sc) conversion process. It has been proposed that PrP(Sc) accumulation in prion diseases may induce aberrant activation of lysosomal activity, which has been shown to result in neurodegeneration in a number of diseases, especially lysosomal storage disorders. Among such diseases, only the ones resulting from defects in GAGs degradation are accompanied by secretion of large amounts of GAG metabolites in urine. In this work, we show that GAGs are secreted in the urine of prion-infected animals and humans, and surprisingly, also in the urine of mice ablated for the PrP gene. We hypothesize that both the presence of PrP(Sc) or the absence of PrP(C) may alter the metabolism of GAGs.     

Computer-generated three-dimensional animation of the mitral valve

OBJECTIVE: Three-dimensional motion-capture data offer insight into the mechanical differences of mitral valve function in pathologic states. Although this technique is precise, the resulting time-varying data sets can be both difficult to interpret and visualize. We used a new technique to transform these 3-dimensional ovine numeric analyses into an animated human model of the mitral apparatus that can be deformed into various pathologic states. METHODS: In vivo, high-speed, biplane cinefluoroscopic images of tagged ovine mitral apparatus were previously analyzed under normal and pathologic conditions. These studies produced serial 3-dimensional coordinates. By using commercial animation and custom software, animated 3-dimensional models were constructed of the mitral annulus, leaflets, and subvalvular apparatus. The motion data were overlaid onto a detailed model of the human heart, resulting in a dynamic reconstruction. RESULTS: Numeric motion-capture data were successfully converted into animated 3-dimensional models of the mitral valve. Structures of interest can be isolated by eliminating adjacent anatomy. The normal and pathophysiologic dynamics of the mitral valve complex can be viewed from any perspective. CONCLUSION: This technique provides easy and understandable visualization of the complex and time-varying motion of the mitral apparatus. This technology creates a valuable research and teaching tool for the conceptualization of mitral valve dysfunction and the principles of repair.