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Background: Recruitment of peripheral proteins to the inner membrane complex (IMC) of the malaria parasite can be mediated by N-terminal acylation. Results: Characterization of substrate determinants and identification of an IMC-localized palmitoyl acyltransferase PfDHHC1. Conclusion: Residues close to palmitoylation sites interfere with specific IMC recruitment. PfDHHC1 represents an apicomplexan-specific PAT. Significance: Dissection of palmitoylation for protein recruitment to the inner membrane complex in P. falciparum.

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Image quality and safety of magnetic resonance (MR) imaging were evaluated in vitro and in eight patients with the most commonly employed metallic biliary endoprosthesis. In vitro, the stent produced no tip deflection at 0.6 or 1.5 T. Trace magnetic susceptibility artifact, similar to artifact from a column of air, paralleled the stent. In patients, image degradation was minimal with conventional pulse sequences. Middle-field-strength spin-echo images revealed minimal artifacts indistinguishable from those produced by pneumobilia.

Objective: To compare the degree of small bowel distension achieved by 3% sorbitol, a high osmolarity solution, and a psyllium-based bulk fibre as oral contrast agents (OCAs) in MR enterography (MRE). Methods: This retrospective study was approved by our institutional review board. A total of 45 consecutive normal MRE examinations (sorbitol, n 5 20; psyllium, n 5 25) were reviewed. The patients received either 1.5 l of 3% sorbitol or 2 l of 1.6 g kg 21 psyllium prior to imaging.Quantitative small bowel distension measurements were taken in five segments: proximal jejunum, distal jejunum, proximal ileum, distal ileum and terminal ileum by two independent radiologists. Distension in these five segments was also qualitatively graded from 0 (very poor) to 4 (excellent) by two additional independent radiologists. Statistical analysis comparing the groups and assessing agreement included intraclass coefficients, Student's t-test and Mann-Whitney U-test.Results: Small bowel distension was not significantly different in any of the five small bowel segments between the use of sorbitol and psyllium as OCAs in both the qualitative (p 5 0.338-0.908) and quantitative assessments (p 5 0.083-0.856). The mean bowel distension achieved was 20.1 6 2.2 mm for sorbitol and 19.8 6 2.5 mm for psyllium (p 5 0.722). Visualization of the ileum was good or excellent in 65% of the examinations in both groups. Conclusion: Sorbitol and psyllium are not significantly different at distending the small bowel and both may be used as OCAs for MRE studies. Advances in knowledge: This is the first study to directly compare the degree of distension in MRE between these two common, readily available and inexpensive OCAs.MR enterography (MRE) is an imaging technique used to evaluate the small bowel for diagnoses that include inflammatory bowel disease and neoplasms. Sufficiently distending the small bowel with an oral contrast agent (OCA) is critical, as collapsed loops may hide or mimic abnormalities.The OCAs employed in MRE can be classified as positive, negative or biphasic contrast agents according to their signal properties on T 1 and T 2 weighted imaging. Biphasic contrast agents typically provide low signal intensity on T 1 weighted imaging and high signal intensity on T 2 weighted imaging (T2W), and are most commonly used today because of their favourable signal characteristics for detecting bowel pathology. Water is a biphasic contrast agent, but its rapid physiological absorption from the small bowel necessitates the use of additives. These additives are often highly osmolar agents or non-osmotic agents that form hydrogels that trap water molecules in the bowel lumen. Combinations of highly osmolar agents and non-osmotic agents are also frequently used, as in the case of sorbitol and locust bean gum. 1,2Ideally, the chosen contrast agent should (i) provide adequate distension of the entire small bowel, (ii) provide uniform and homogenous opacification of the lumen, (iii) provide good delineation of the bowel wall, (iv) be below cost and eas...