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Background: Intra-abdominal hypertension is known as a factor affecting cerebral haemodynamics. Sustainably elevated abdominal pressure may disturb the balance of intracranial/blood pressure ratio, eventually developing perfusion pressure to drop.

Tacrine is a medication applied in cases of mild to moderate dementia in Alzheimer's disease. By blocking acetylcholinesterase activity the drug increases the concentration of acetylcholine, whose effects influence the functions of different organs and systems of the body. The effect of tacrine on smooth muscle preparations isolated from rat stomach was studied by isometric registration of muscle contractility. Our investigations found a specific significant systematic decrease in the strength of consecutive tacrine-induced contractions of smooth muscle preparations, a phenomenon known as tachyphylaxis. The tacrineinduced tachyphylaxis was significantly inhibited by SQ22536 (inhibitor of adenylate cyclase activity), by blockers of nitric oxide synthase and KT5823 (inhibitor of protein kinase G). The process was not influenced by cyclopiazonic acid (specific blocker of sarco/endoplasmic reticulum Ca-ATPase,) and atropine (blocker of M-cholinergic receptors). We hypothesize that the overlapping and different time-development of the two opposing processes: smooth muscle contraction caused by acetylcholinesterase inhibition and tacrine-induced relaxation influenced by synthesis of nitric oxide, results in tachyphylaxis. [ABSTRACT FROM AUTHOR]

Hyoscine and drotaverine effectiveness was compared for the purposes of achieving optimum distension following insufflation in CT colonography. The in vitro effects of hyoscine and drotaverine on tone and contractility of SM preparations isolated from different areas of human colon were studied by isometric registration of contractile activity. Both medications have a relaxing effect on SM preparations and inhibit their spontaneous contractions. The drotaverine-induced effects were reliably more marked than the hyoscine-induced ones. CT colonography was performed in 70 patients who were injected with equal doses of either hyoscine (n=32) or drotaverine (n=38). The degree of drug-induced distension in both groups was determined by measuring the lumen of the colon on a 2D reconstruction. In most colon areas the width of the distended lumen was greater in the drotaverine-treated patients. We concluded that drotaverine can be used as a means to facilitate colonic distension. [ABSTRACT FROM AUTHOR]

The patients’ discomfort during CT colonography determines which method is used and its frequency of use. The discomfort is largely associated with the colon’s insufflation with gas. A system for an automatic room-air insufflation has been developed that ensures a continuous and steady air insufflation and an increase in colonic pressure and enables a relatively fast decompression. This system provides constant pressure monitoring and can alert the operator, if necessary. The degree of discomfort was evaluated for 36 patients, who were subjected to manual and automated air insufflation. The degree of the colonic distension achieved by the two methods was compared. The data analysis showed a significantly lower level of discomfort in patients with automated air insufflation. The degree of colonic distension was evaluated by comparing the diameters of similar segments of the colon, as well as by the subjective opinion of the operator. The distension with automated air insufflation was higher than that with manual air insufflation. In some cases there was a significant difference (P<0,05). In conclusion, the results show that the automatic insufflation of air at room temperature can be used to optimize CT colonography. [ABSTRACT FROM AUTHOR]

A The acetylcholinesterase inhibitors galantamine and tacrine are used to treat Alzheimer’s disease. However, these compounds also affect the gastrointestinal (GI) tract. Here, we compared and analyzed both the effects of galantamine-and tacrine on the evacuatory kinetics of the GI tract in rats. Rats were untreated (n=15) or treated with galantamine (one daily dose of 1 mg/kg per os for 21 days; n=17) or tacrine (one daily dose of 0.5 mg/kg per os for 21 days; n=13) and evacuatory kinetics were assessed using radiological methods. Galantamine initially slowed and then accelerated evacuation, which is characteristic of the majority of cholinesterase inhibitors and is a result of the endogenous acetylcholine accumulated in the GI tissues. In the tacrine-treated rats the contrast medium was kept in the stomach and cecum and its evacuation time was reliably increased. These results indicate that when administered for 20 days, galantamine and tacrine have different effects on motor and evacuatory function in the GI tract of rats, because at certain levels of the tract the tacrine-action is dominated by specific non-cholinergic and non-anticholinesterase mechanisms. [ABSTRACT FROM AUTHOR]