Ischemic Colitis in Sickle Cell Disease: A Case Report of a Diagnostic Challenge.

Microvascular occlusion serves as the underlying mechanism for the multitude of clinical manifestations of sickle cell disease, one of the most prevalent hemoglobinopathies worldwide. Recurrent painful episodes are the hallmark of this condition. Abdominal pain attributed to an acute painful episode can be indistinguishable from a separate and/or more serious intra-abdominal disease process, representing a significant diagnostic dilemma for clinicians. Here we present a rare case of ischemic colitis due to vascular occlusion in a 28-year-old man with sickle cell disease.

IgG4-Related Cholangiopathy and Its Mimickers: A Case Report and Review Highlighting the Importance of Early Diagnosis.

Immunoglobulin (Ig) G4 (IgG4)-related disease is a recently described clinical entity that can involve multiple organs. It is an autoimmune disorder characterized by a dense lymphoplasmacytic infiltrate, storiform fibrosis, and obliterative phlebitis. A key distinguishing factor is its dramatic response to steroid therapy. Although best described in cases of autoimmune pancreatitis, IgG4-related disease has also been implicated in patients with cholangitis and is now commonly referred to as IgG4-related cholangiopathy. It is characterized by elevated serum IgG4 levels, an IgG4-positive plasma cell infiltration with storiform fibrosis/obliterative phlebitis of the bile duct wall, and a response to steroids. It is crucial to differentiate IgG4-related cholangiopathy from its mimickers, such as primary biliary cholangitis, secondary biliary cholangitis, primary sclerosing cholangitis, secondary sclerosing cholangitis, and cholangiocarcinoma, because treatment modalities and outcomes of IgG4-related cholangiopathy differ significantly from these disorders. Here, we present an interesting case of IgG4-related cholangiopathy, discuss clinical and pathological features crucial to its early diagnosis, and compare and contrast this condition with its potentially confounding mimickers.

Apparent alkyl transfer and phenazine formation via an aryne intermediate.

Treatment of chlorotriaryl derivatives 3a and 3d or fluorotriaryl derivatives 3b and 3e with potassium diisopropylamide afforded alkyl-shifted phenazine derivatives 5a/5b, rather than the expected 9-membered triazaorthocyclophane 2a. The phenazine derivatives were isolated in 78-98% yield depending on the halogen and alkyl group present. In the absence of the halogen (chloro or fluoro), the apparent alkyl shift proceeds more slowly and cannot proceed via the intermediacy of the aryne intermediate. Mechanistic possibilities include intramolecular nucleophilic attack on an aryne intermediate leading to a zwitterionic intermediate and alkyl transfer via a 5-endo-tet process, or via a Smiles rearrangement.