Arylalkylamine N-acyltransferase-like 22 (AANATL2) from Drosophila melanogaster was expressed and shown to catalyze the formation of long-chain N-acylserotonins and N-acydopamines. Subsequent identification of endogenous amounts of N-acylserotonins and colocalization of these fatty acid amides and AANATL2 transcripts gives supporting evidence that AANATL2 has a role in the biosynthetic formation of these important cell signalling lipids.
Long-chain fatty acid amides are cell-signaling lipids identified in mammals and, recently, in invertebrates, as well. Many details regarding fatty acid amide metabolism remain unclear. Herein, we demonstrate that Drosophila melanogaster is an excellent model system for the study long-chain fatty acid amide metabolism as we have quantified the endogenous levels of N-acylglycines, N-acyldopamines, N-acylethanolamines, and primary fatty acid amides by LC/QTOF-MS. Growth of Drosophila melanogaster on media supplemented with [1-13C]-palmitate lead to a family of 13C-palmitate-labeled fatty acid amides in the fly heads. The [1-13C]-palmitate feeding studies provide insight into the biosynthesis of the fatty acid amides.
The long-chain fatty acid amides are an emerging family of bioactive lipids with members that include N-acyl amino acids, primary fatty acid amides (PFAMs), N-acylarylalkylamides, N-acylethanolamines, and N-monoacylpolyamines. Fatty acid amides were first identified from biological sources over 50 years ago with the isolation and identification of N-palmitoylethanolamine from egg yolk in 1957 (1) and, in 1965, N-palmitoylethanolamine and N-stearoylethanolamine in several tissues from rat and guinea pig (2). The discovery of N-arachidonoylethanolamine (anandamide) as the endogenous ligand for the mammalian brain cannabinoid receptor CB 1 sparked a dramatic interest in the fatty acid amides (3). Since these early discoveries, a diversity of long-chain fatty acid amides have been identified in mammals and, more recently, in invertebrates as well (4)(5)(6)(7)(8).The N-fatty acylglycines, a subclass of the N-fatty acyl amino acids, are an important class of cell signaling lipids that are distributed throughout the central nervous system and the rest of the body (6, 7, 9). Identification of glycine conjugates dates back to the 1820s with the identification of N-benzoylglycine (hippurate) as a mammalian metabolite (10). N-arachidonoylglycine was the first longchain N-acylglycine identified from a mammalian source and was determined to have anti-nociceptive and antiinflammatory effects in rat models of pain (11). Since
Background:
Early detection of posterior shoulder dislocation in infants with brachial plexus birth palsy (BPBP) is essential, but it may be difficult to accomplish with physical examination alone. The aim of this study was to determine the prevalence of shoulder dislocation in patients with BPBP using ultrasound and to identify which physical examination measurements correlated most with dislocation in these patients.
Methods:
This study was a retrospective review of data obtained in an ultrasound screening program of infants with BPBP born from January 2011 to April 2014. Physical examination included the use of the Active Movement Scale (AMS) and measurement of passive external rotation of the shoulder. Ultrasound measurements included PHHD (percentage of the humeral head displaced posterior to the axis of the scapula) and the alpha angle (intersection of the posterior scapular margin with a line tangential to the humeral head through the glenoid). Shoulder dislocation was defined as both a PHHD of >0.5 and an alpha angle of >30°.
Results:
Of sixty-six infants who had undergone a total of 118 ultrasound examinations (mean, 1.8; range, 1 to 5), 19 (29%) demonstrated shoulder dislocation with the shoulder positioned in internal rotation; the dislocation was first detected between 2.1 and 10.5 months of age. Infants with a dislocated shoulder demonstrated significantly less mean passive external rotation in adduction (mean, 45.8° versus 71.4°, p < 0.001) and a greater difference between internal rotation and external rotation AMS scores (mean, 5.5-point versus 3.3-point difference, p < 0.001) than those without shoulder dislocation. Passive external rotation in adduction was a better measure for discriminating between dislocation and no dislocation (area under receiver operating characteristic curve [AUC] = 0.89) than was the difference between internal and external rotation AMS scores (AUC = 0.73). A cutoff of 60° of passive external rotation in adduction (≤60° versus° >60) yielded a sensitivity of 94% and a specificity of 69%.
Conclusions:
Shoulder dislocation is common in infants with BPBP; 29% of the infants presenting to our tertiary care center had a dislocation during their first year of life. Ultrasound shoulder screening is appropriate for infants with BPBP. If passive external rotation in adduction is used to determine which infants should undergo ultrasound, ≤60° should be utilized as the criterion to achieve appropriate sensitivity.
Level of Evidence:
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.