Invasive surgical procedures for gastric volume reduction or bypass have been considered the most effective approach to sustainable long-term weight reduction. However, non-invasive techniques for dynamic volume reduction from inside the stomach are lacking. The aim of this study was to propose temporary, permeable, controllable pseudobezoars for non-invasive, long-term sustainable gastric volume reduction and to test them in pilot human studies. Permeable sac-like carriers made from biocompatible and biodegradable material were filled with expandable superabsorbent fiber and polymer granules. The implements were designed to prevent the expulsion of the pseudobezoars through the pylorus for a controlled time period. The pseudobezoars were administered transorally to two human patients (2M, 78.9 kg/174 cm, girth 88.1 cm, and 89.7 kg/175, girth 95.2 cm). Body weight dynamics, girth, level of satiety, stools, bowel regularity and notable side effects were monitored in three distinct 1 month periods: baseline, therapy and washout. Sonographic verification of the presence of pseudobezoars in the stomachs of both subjects was performed at the end of the therapy month and was repeated at the end of the washout period to examine the clearance of the implements. During the therapy month, both individuals exhibited significant weight and girth reduction (p < 0.05), and substantially increased satiety levels. The patients retained their bowel regularity and did not report any notable side effects. The temporary pseudobezoars were clearly noticeable sonographically in both patients at the end of the therapy month and cleared after its discontinuation. Controllable temporary pseudobezoars were designed and tested in pilot studies.

The kinetics and mechanism of ozone reactions with aliphatic ethers in CCl4 solution have been investigated with a set of six symmetrical ethers: ethyl, chloroethyl, iso-propyl, n-butyl, iso-amyl, and n-amyl. The corresponding kinetic constants at ambient temperature are 3.1, 0.035, 5.4, 6.3, 6.8, and 7.8 l/(mol s). Upon ozonation of n-butylether the main products are butylalcohol, butylaldehyde (butyric acid), and butylbutyrate. A common precursor of these products is the a -hydrotrioxybutylether. Experimental values of the preexponential factors are compared with those calculated according to the activation complex theory with linear or cyclic form of the activated complex. The cyclic form of the activated complexes is unfavorable because of the kinetic factor. Abstraction of hydrogen atom or the far less probable hydride ion abstraction from a-position in the ether molecules is the rate-determining step of ozonation. The ratedetermining factors are the electron density and geometry of the reaction center and the energy of the a-C-H bonds. 0 1995 John Wiley & Sons, Inc.

The growing worldwide obesity epidemic has prompted the development of two main treatment streams: 1) conservative approaches and 2) invasive techniques. However, only invasive surgical methods have delivered significant and sustainable benefits. Therefore, contemporary research exploration has focused on the development of gastric volume reduction methods having noninvasive administration and termination, while featuring a safe but reliable and long-term sustainable weight loss effect similar to the one delivered by bariatric surgeries. This antiobesity approach is based on placing external devices in the stomach ranging from intragastric balloons to temporary pseudobezoars for a predetermined amount of time. The present review examines the evolution of these techniques from invasively positionable and removable units to completely noninvasive patient-controllable implements. Comparative discussion over the available pilot and clinical studies related to temporary controllable pseudobezoars outlines this new concept as an alternative gastric volume reduction antiobesity strategy. Available short-term studies reported an average weight loss of 6% for a 1-month period. The beneficial features of this method include patient-specific design, performance flexibility, full controllability, and particularly low level or lack of side effects. More multicenter, placebo-controlled, long-term studies on a significant number of patients and further technological improvements of the design of the pseudobezoars are required before the technique can be considered a reliable alternative to present-day bariatric surgeries.

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