Rectal cancer DFP dedicated issue: abdominal radiology

Abdominal Radiology -     

Review of thoracic duct anatomical variations and clinical implications

The thoracic duct (TD) transports ingested fat, drains lymph from the gastrointestinal vascular bed, and delivers the lymph to central veins in the neck. Preliminary evidence suggests that diversion of TD lymph may mitigate the severity of end‐organ dysfunction in critical illness. Variations in the anatomy of the TD may determine whether reliable and safe cannulation of the duct, a necessary step for diversion, is possible. A systematic review was undertaken using the Google Scholar, MEDLINE, PubMed, and Scopus databases until 31st March, 2013. Both English and non‐English articles were searched for, and surgical, cadaveric, and radiologic studies were included. Fifty‐seven articles from the past 102 years were retrieved. There are significant variations in the anatomy of the TD in terms of its formation at the cisterna chyli, its course through the thorax, and its termination in the venous system. The most common site of termination is at the internal jugular vein (46%), followed by the jugulosubclavian angle (32%), and the subclavian vein (18%). An improved understanding of the anatomy of the TD would help surgeons to avoid inadvertent injury and potentially afford new opportunities for diagnosis and intervention in patients with critical illness. Clin. Anat. 637–644, 2014. © 2013 Wiley Periodicals, Inc.     

Pyrroline-5-carboxylate synthase activity in mammalian cells.

Although glutamic acid is known to be a precursor for proline biosynthesis, the enzymatic conversion of glutamic acid to pyrroline-5-carboxylic acid, the immediate precursor of proline, has not been demonstrated in cell-free systems. By providing appropriate concentrations of ATP and NADPH and blocking further metabolism of pyrroline-5-carboxylic acid, we have developed a method for measuring the formation of pyrroline-5-carboxylic acid from glutamic acid in homogenates of mammalian cells. We have designated this activity pyrroline-5-carboxylate synthase. To confirm that our assay is a valid measure of the initial step in proline biosynthesis from glutamic acid, we have compared two mutant lines of Chinese hamster ovary cell. Proline prototrophic cells, which can synthesize proline from glutamic acid, have easily measurable pyrroline-5-carboxylate synthase activity (5.97 nmol of pyrroline-5-carboxylic acid per hr per mg of homogenate protein). In contrast, proline auxotrophic cells, which are unable to synthesize proline from glutamic acid, have no detectable pyrroline-5-carboxylate synthase activity.