Super paramagnetic iron oxide contrast-enhanced magnetic resonance imaging was useful in differentiating an insulinoma from an accessory spleen: a case report with review of literature.

When a neuroendocrine tumor with abundant blood flow is located in the pancreatic tail, it is difficult to distinguish it from accessory spleen. The patient was a 71-year-old woman who was admitted with impaired consciousness and hypoglycemia, raising suspicion of insulinoma. The selective arterial calcium injection test suggested a lesion in the pancreatic tail. Contrast-enhanced computed tomography and magnetic resonance imaging (MRI) showed a mass in the splenic hilum; however, its continuity with the pancreas was unclear. Contrast-enhanced MRI using super paramagnetic iron oxide (SPIO) showed no SPIO uptake in the splenic hilar mass. SPIO contrast-enhanced MRI is considered useful for differentiating pancreatic endocrine tumors from paraspleen tumors.

Characteristics of the nuclear form of the Arabidopsis transcription factor AtbZIP60 during the endoplasmic reticulum stress response.

Accumulation of unfolded proteins in the endoplasmic reticulum (ER) of eukaryotic cells triggers the transcriptional induction of ER-resident molecular chaperones to maintain cellular homeostasis, termed the ER stress response. Previously we isolated AtbZIP60, a membrane-bound transcription factor involved in the Arabidopsis ER stress response whose activity is controlled by proteolytic cleavage. In this study we characterized the active form of AtbZIP60 localized in the nucleus during the ER stress response. Transient assay using Arabidopsis protoplasts revealed that activation of BiP promoters by AtbZIP60 is dependent on the cis-elements plant-unfolded protein response element (P-UPRE) and ER stress response element (ERSE). Transcriptional activation activity of AtbZIP60 was mainly located in the region for amino acids 41-80 of AtbZIP60. Size exclusion chromatography analysis showed that the nuclear form of AtbZIP60 exists as a protein complex of approximately 260 kDa. On the basis of the present study combined with observations described in the literature, possible mechanisms of AtbZIP60's action in the nucleus are discussed.