Laparoscopic cholecystectomy for melanoma metastatic to the gallbladder: is it an adequate surgical procedure? Report of a case and review of the literature

<p>Abstract</p> <p>Background</p> <p>Only 2% to 4% of patients with melanoma will be diagnosed with gastrointestinal metastasis during the course of their disease. The most common sites of gastrointestinal metastases from melanoma include the small bowel (35%–67%), colon (9%–15%) and stomach (5%–7%), with a median survival of 6–10 months after surgery, and 18% survival at five years. Metastatic melanoma to the gallbladder is extremely rare and it is associated with a very poor prognosis.</p> <p>Case presentation</p> <p>We report a case of a 54-year old man presented to observation with diagnosis of 6.1 mm thick, Clark's level IV, ulcerated melanoma of the trunk, developing in the course of the disease metastatic involvement of the gallbladder as first site of recurrence, treated by laparoscopic cholecystectomy. To date only few cases of patients with metastatic melanoma of the gallbladder treated by this surgical procedure have been reported in literature.</p> <p>Conclusion</p> <p>Gallbladder metastasis represents a rare event as a first site of recurrence. It must be considered a possible expression of systemic disease also despite radiological absence of other metastatic lesions. Laparoscopic approach has a possible therapeutic role, but open surgery has also a concomitant diagnostic purpose because gives the possibility of manual exploration of abdominal cavity, useful particularly to reveal bowel metastatic lesions, not easily identifiable by preoperative imaging examinations.</p

Investigating the dynamics of surface-immobilized DNA nanomachines

Surface-immobilization of molecules can have a profound influence on their structure, function and dynamics. Toehold-mediated strand displacement is often used in solution to drive synthetic nanomachines made from DNA, but the effects of surface-immobilization on the mechanism and kinetics of this reaction have not yet been fully elucidated. Here we show that the kinetics of strand displacement in surface-immobilized nanomachines are significantly different to those of the solution phase reaction, and we attribute this to the effects of intermolecular interactions within the DNA layer. We demonstrate that the dynamics of strand displacement can be manipulated by changing strand length, concentration and G/C content. By inserting mismatched bases it is also possible to tune the rates of the constituent displacement processes (toehold-binding and branch migration) independently, and information can be encoded in the time-dependence of the overall reaction. Our findings will facilitate the rational design of surface-immobilized dynamic DNA nanomachines, including computing devices and track-based motors