Renal aplasia in humans is associated with RET mutations.

In animal models, kidney formation is known to be controlled by the proteins RET, GDNF, and GFRA1; however, no human studies to date have shown an association between abnormal kidney development and mutation of these genes. We hypothesized that stillborn fetuses with congenital renal agenesis or severe dysplasia would possess mutations in RET, GDNF, or GFRA1. We assayed for mutations in these genes in 33 stillborn fetuses that had bilateral or unilateral renal agenesis (29 subjects) or severe congenital renal dysplasia (4 subjects). Mutations in RET were found in 7 of 19 fetuses with bilateral renal agenesis (37%) and 2 of 10 fetuses (20%) with unilateral agenesis. In two fetuses, there were two different RET mutations found, and a total of ten different sequence variations were identified. We also investigated whether these mutations affected RET activation; in each case, RET phosphorylation was either absent or constitutively activated. A GNDF mutation was identified in only one fetus with unilateral agenesis; this subject also had two RET mutations. No GFRA1 mutations were seen in any fetuses. These data suggest that in humans, mutations in RET and GDNF may contribute significantly to abnormal kidney development.

Total Aortic Arch Replacement: Advantages of Varied Techniques.

We review the operative techniques of aortic arch replacement. Aortic arch replacement presents several formidable challenges, as it requires arresting the circulation to the body and replacement of the brachiocephalic vessels with special consideration for protecting the central nervous system. Perfusion strategies, selective antegrade cerebral perfusion, and operative graft selection are key elements in aortic arch replacement surgery. Standard approaches include the island technique, the branched graft technique, and the "Spielvogel" trifurcated graft technique-each having its own advantages. In addition, thoracic aortic aneurysms involving the arch and descending aorta pose a substantial surgical challenge and often require hybrid or nonclamp technique with staged operative interventions. Hybrid and endovascular (thoracic endovascular aortic repair) techniques for the descending aorta are evolving and require consideration in operative planning. Areas of controversy include management of the subclavian artery, extent of distal arch replacement, elephant trunk and hybrid frozen elephant trunk techniques, and use and timing of staged approaches. Aortic arch replacement remains a complex, potentially difficult procedure. Better understanding of the potential open approaches to arch replacement will optimize the potential outcomes for patients. Aortic arch pathology is best served by tailoring the procedure to the patient-specific anatomy and pathology.

Aortic Translocation for Repair of Transposition of the Great Arteries (S,D,L) With Ventricular Septal Defect and Pulmonic Stenosis.

Biventricular repair for (S,D,L) transposition with ventricular septal defect, pulmonary stenosis, and superior-inferior ventricular malposition has not been described, to our knowledge. Herein we report biventricular repair of this complex lesion by aortic translocation.

Short-term preoperative diet modification reduces steatosis and blood loss in patients undergoing liver resection.

BACKGROUND: Steatosis and steatohepatitis have been associated with increased morbidity and mortality after liver resection. Our objective was to determine the effect of a preoperative calorie-restricted diet on steatosis and steatohepatitis in patients undergoing liver resection. METHODS: We studied 111 consecutive patients who had major elective hepatic resections. More than 90% of the patients had cancer resections. The mean body mass index was 27.2; 32% had a body mass index ≥30. A week-long calorie- and fat-restricted diet was instituted in the most recent patient group (n = 51). We retrospectively evaluated steatosis and steatohepatitis in the diet and no-diet control groups. Clinical outcomes of the 2 groups, including complications and blood loss, were compared. RESULTS: The preoperative diet patients had less steatosis (15.7% vs 25.5% of hepatocytes containing fat, P = .05) than the nondiet controls. A lower percentage of patients in the diet group had steatohepatitis than in the nondiet group (15% vs 27%, P =.02). Preoperative diet patients had less mean intraoperative blood loss than nondiet patients (600 mL vs 906 mL, P = .002). There was no difference in overall or infectious complications between the groups. CONCLUSION: We have shown for the first time that short-term calorie restriction before liver resection significantly reduces both hepatic steatosis and steatohepatitis. Dietary modification also was associated with decreased intraoperative blood loss. This intervention is easily instituted; therefore, it is clinically feasible.