Symptomatic Cholelithiasis of a Remnant Gallbladder after Open Cholecystectomy.

BACKGROUND: Recurrent abdominal pain, particularly in the right upper quadrant (RUQ) in a patient with a history of cholecystectomy, known as postcholecystectomy syndrome, requires a broad differential diagnosis. Pathology of a retained gallbladder remnant is an exceedingly rare etiology of this pain. CASE REPORT: A 49-year-old woman who had previously undergone an open cholecystectomy presented to the emergency department with several hours of postprandial RUQ pain and emesis. Liver function tests and lipase were not significantly elevated. RUQ ultrasonography revealed a cystic structure containing a stone with mild prominence of the common bile duct at 7 mm, and magnetic resonance cholangiopancreatography confirmed the presence of a remnant gallbladder without common bile duct obstruction. Her pain subsided, she tolerated a diet, and was discharged with a referral for an elective cholecystectomy. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Abdominal pain is the most common chief complaint of patients presenting to the emergency department in the United States, and emergency physicians routinely encounter patients with postcholecystectomy syndrome. Emergency physicians should not exclude the possibility of remnant gallbladder pathology, such as symptomatic cholelithiasis or cholecystitis, in patients presenting with symptoms concerning for biliary colic, even if the patient has undergone previous cholecystectomy.

Mapping the mechanical properties of cholesterol-containing supported lipid bilayers with nanoscale spatial resolution.

It has been demonstrated that many biological processes are influenced by mechanical changes in membranes comprised of a variety of lipid components. As a result, the ability to map physicomechanical properties of surfaces with high temporal and spatial resolution is desirable. Tapping mode atomic force microscopy (AFM) has proven to be a useful technique for imaging biological surfaces due to its ability to operate in solution; however, access to information concerning the mechanical properties of these surfaces can also be obtained by reconstructing the time-resolved tip/sample force interactions during the imaging process. An advantage of such an approach is the direct correlation of topographical features with mechanical properties. Reconstruction of the tip/sample force is achievable by a technique called scanning probe acceleration microscopy (SPAM), which treats the cantilever as an accelerometer. The acceleration, which is directly related to the tip/sample force, of the cantilever is obtained by taking the second derivative of the cantilever deflection signal during a tapping mode AFM experiment in solution with standard cantilevers. Herein, we describe the applicability of SPAM to study mechanical properties of supported lipid bilayers with nanoscale spatial resolution via numerical simulations and experiment. The maximum and minimum tapping forces respond to changes in specific surface mechanical properties. Furthermore, we demonstrate how these changes can be used to map relative changes in the Young's modulus and adhesive properties of supported total brain lipid extract bilayers containing exogenous cholesterol. Finally, the ability of SPAM to distinguish nanoscale lipid raft domains based on changes in local mechanical properties is demonstrated.