Acute alterations in anorectal manometry induced by proximal and distal sphincterotomy. Experimental studies on piglets

Anal incontinence causes psychological, social and adaptive troubles prejudicial to the quality of life both in children and adults. Therefore, the detailed knowledge of its causes and the improvement of diagnostic and therapeutic methods increase the possibilities of a more adequate social life to patients with congenital anomalies or sphincteric lesions or degenerations. In this work, a manometric study was developed through an experimental model so as to analyze alterations in behavior of muscle groups responsible for the anorectal sphincteric mechanism, previous to and after proximal and distal lesions. Twenty-two pigs aged between 25 and 30 days, weighing 5-7 kg, were randomly divided into two groups. They were submitted to lesions of different levels in the anorectal muscle. The animals were studied by anorectal manometry (rectoanal inhibitory reflex and vector volume) before and after the lesions. The Student t test and the Wilcoxon test were applied for the statistical analyses, considered p <= 0.05. The proximal lesion preserved sphincter relaxation, retarding its closure [speed of relaxation recovery 4.35 +/- 2.10 vs. 2.70 +/- 1.32 mm/s (p = 0.001)], but it reduced the maximum pressure [62.45 +/- 20.02 vs. 40.36 +/- 12.59 mmHg (p = 0.004)] and vector volume [2,749 +/- 921 vs. 1,591 +/- 1,379 mmHg(2)cm (p = 0.005)]. There was an increment in the high-pressure zone [5.09 +/- 1.04 vs. 6.36 +/- 1.50 mm (p = 0.005)], but the asymmetry percentage and the sphincter length were maintained. The distal lesion did not alter the rectoanal inhibitory reflex, the high-pressure zone length, the asymmetry percentage, or the vector volume. Nevertheless, the sphincter length increased [11.82 +/- 2.82 vs. 14.09 +/- 2.39 mm (p = 0.022)] and the maximum pressure decreased [60.55 +/- 22.05 vs. 40.91 +/- 13.41 mmHg (p = 0.004)]. The alterations observed due to proximal lesion of the anorectal sphincter suggest a direct and more important interference of the levator ani muscle in the function of the sphincteric musculature than that caused by the distal lesion.

Molecular Sieve Silica Membranes

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Hydrogen Storage by Carbon Nanotubes

Encyclopedia of Nanoscience and Nanotechnology® is the World's first encyclopedia ever published in the field of nanotechnology. The 10-volume Encyclopedia is an unprecedented single reference source that provides ideal introduction and overview of most recent advances and emerging new aspects of nanotechnology spanning from science to engineering to medicine. Although there are many books/handbook and journals focused on nanotechnology, no encyclopedic reference work has been published covering all aspects of nanoscale science and technology dealing with materials synthesis, processing, fabrication, probes, spectroscopy, physical properties, electronics, optics, mechanics, biotechnology, devices, etc. The Encyclopedia fills this gap to provide basic information on all fundamental and applied aspects of nanotechnology by drawing on two decades of pioneering research. It is the only scientific work of its kind since the beginning of the field of nanotechnology bringing together core knowledge and the very latest advances. It is written for all levels audience that allows non-scientists to understand the nanotechnology while providing up-to-date latest information to active scientists to experts in the field. This outstanding encyclopedia is an indispensable source for research professionals, technology investors and developers seeking the most up-to-date information on the nanotechnology among a wide range of disciplines from science to engineering to medicine.