David E Hartley — Page 2

PubMed2003

Plain radiographic surveillance of abdominal aortic stent-grafts: the Liverpool/Perth protocol.

PURPOSE: To present a protocol for plain radiographic surveillance of abdominal aortic stent-grafts that addresses the main variables in need of standardization: (1) patient position, (2) radiographic centering point, and (3) focus-to-film distance. TECHNIQUE: Our policy is to perform baseline anteroposterior and lateral films following endoluminal grafting and repeat the studies annually. These are the most important films to assess migration and component separation; supplementary right and left posterior oblique radiographs may help identify wireform fractures. It is best to perform radiography before computed tomography if both tests are scheduled for the same day, as excretion of intravenous contrast opacifies the renal collecting systems and interferes with radiographic analysis. CONCLUSIONS: Evaluation of the radiographs depends on the design of the stent-graft, so it is important to understand graft construction and the position of the radiopaque markers to best assess changes on follow-up films.

Aortic Aneurysm, Abdominal↗

PubMed2002

Renal response to arginine vasopressin during the oestrous cycle in the rat: comparison of glucose and saline infusion using physiological doses of vasopressin.

The renal response to arginine vasopressin in the rat has been shown to depend on reproductive status. However there is no consensus as to when the kidney is most responsive. The varying results could depend on the protocol and the dose of hormone used. A study has been performed, with physiological doses of vasopressin, comparing the responses during infusion of hypotonic saline and glucose. After an equilibration period of 150 min, conscious rats were infused on each of the four days of the oestrous cycle with either isotonic saline (0.077 M) or 0.14 M glucose for a control period of 45 min. Vasopressin was then infused at 10-40 fmol min(-1) for 1 h, followed by a recovery period of 90 min. Timed urine samples were collected for determination of volume, sodium concentration and osmolality. During the control period urine flow was greatest at oestrus and dioestrus day 2 and sodium excretion on dioestrus day 2 irrespective of the infusate. Vasopressin concentrations achieved lay within the physiological range and no difference was observed between the different days for a given dose. Infusion of vasopressin in both saline and glucose produced a dose-dependent antidiuresis, the greatest responses being seen of pro-oestrus and dioestrus day 2. It was only with the highest rate of infusion that a significant increase in sodium excretion was seen on each day of the cycle and the greatest responses were seen on pro-oestrus and dioestrus day 1 for both infusates. Thus the kidney shows the greatest response to physiological doses of vasopressin at pro-oestrus and dioestrus day 1 irrespective of the infusate employed.

Animals↗