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We study theoretically the entropic elasticity of a semi-flexible polymer, such as DNA, confined to two dimensions. Using the worm-like-chain model we obtain an exact analytical expression for the partition function of the polymer pulled at one end with a constant force. The force-extension relation for the polymer is computed in the long chain limit in terms of Mathieu characteristic functions. We also present applications to the interaction between a semi-flexible polymer and a nematic field, and derive the nematic order parameter and average extension of the polymer in a strong field.

Acotiamide hydrochloride (acotiamide; N-[2-[bis(1-methylethyl) amino]ethyl]-2-[(2-hydroxy-4,5-dimethoxybenzoyl) amino] thiazole-4-carboxamide monohydrochloride trihydrate, Z-338) has been reported to improve meal-related symptoms of functional dyspepsia in clinical studies. Here, we examined the gastroprokinetic effects of acotiamide and its antiacetylcholinesterase activity as a possible mechanism of action in conscious dogs. Acotiamide increased postprandial gastric motor activity in conscious dogs with chronically implanted force transducers and, like itopride, mosapride, and cisapride, exhibited gastroprokinetic activity in these dogs. Furthermore, acotiamide improved clonidine-induced hypomotility and delayed gastric emptying. Acotiamide-enhanced postprandial gastroduodenal motility was suppressed completely by pretreatment with atropine, a muscarinic receptor antagonist. In in vitro studies, acotiamide enhanced acetylcholine-but not carbachol-induced contractile responses of guinea pig gastric antrum strips. Moreover, like itopride and neostigmine, acotiamide inhibited recombinant human and canine stomach-derived acetylcholinesterase (AChE) activity in vitro. The mode of the AChE inhibitory action of acotiamide was selective and reversible. Unlike itopride or mosapride, acotiamide showed no affinity for dopamine D 2 or serotonin 5-HT 4 receptors. With regard to cardiovascular side effects, unlike cisapride, acotiamide did not affect myocardial monophasic action potential duration, QT interval, or corrected QT interval in anesthetized dogs. These results suggest that acotiamide stimulates gastric motility in vivo by inhibiting AChE activity without affecting QT interval. Acotiamide thus represents a beneficial new drug for the treatment of functional dyspepsia involving gastric motility dysfunction, with differences from other prokinetic agents.

Our results indicate that time attenuation curves obtained from triple-phase helical CT in protocol B provide useful information in differentiating chronic pancreatitis from pancreatic adenocarcinoma.

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