Endoscopic bilateral drainage using SEMS for malignant hilar biliary obstruction is more effective than unilateral drainage in terms of cumulative stent patency, especially in cases of cholangiocarcinoma.

The incidence of complications is higher for side-by-side than stent-in stent deployment in bilateral metal stenting. In terms of cumulative stent patency, side-by-side deployment tends to be more effective than stent-in-stent deployment.

Diagnostic criteria for IgG4-SC based on cholangiographic classification are useful for distinguishing it from PCa, PSC, and CC.

We report a novel photochromic molecular system, phenoxyl-imidazolyl radical complex (PIC), in which both a phenoxyl radical site and an imidazolyl radical site are reversibly and simultaneously generated upon UV light irradiation. PIC consists of the three parts: an aromatic linker, a diarylimidazole moiety, and a 4H-cyclohexadienone ring. Upon UV light irradiation, the C-N bond between the 4H-cyclohexadienone ring and the imidazole ring in the colorless closed-ring isomer of PIC undergoes a homolytic cleavage, leading to the formation of the transient colored open-ring isomer. Based on the substituents on the imidazoyl/4H-cyclohexadienone rings and the nature of the aromatic linker, the half-life of the colored open-ring isomer can be varied between tens of nanoseconds and seconds. PIC derivatives containing a 1,2-phenylene linker exhibit high fatigue resistance toward repeated photochromic reactions. Analysis using laser flash photolysis reveals that the absorption spectra of the open-ring isomers are not readily rationalized by a straightforward superposition of the spectra of the two component radical fragments and the photogenerated radicals are electronically coupled through the aromatic linker. Furthermore, the open-ring isomer can be treated as a hybrid of the pure open-shell biradical and closed-shell quinoid resonance structures.

Depression is common in Alzheimer's disease (AD). Clinicoanatomic studies in focal brain injuries and functional imaging studies both in primary depression and in depression secondary to neurologic diseases have demonstrated involvement of the frontal lobe. Frontal involvement has not been established in the depression of AD. We studied the correlation between focal brain metabolic abnormalities and depression in AD. In 53 patients with probable AD of minimal to moderate disability, we assessed the severity of depression using the Neuropsychiatric Inventory and correlated the depression score with regional cerebral glucose metabolism determined by 18F-fluorodeoxyglucose and PET. Depression was present in 19 patients (36%). The depression score correlated significantly with normalized glucose metabolic rates in the bilateral superior frontal and left anterior cingulate cortices. These results indicated an association between depression and decreased activity in the frontal lobe in AD and support frontal involvement, especially in the left side, in depression, irrespective of disease etiology.