Pancreatic neuroendocrine carcinoma with exocrine differentiation in a young cat.

A 35-mo-old spayed female mixed-breed cat with continuous vomiting, emaciation, and abdominal distention for 2 wk was presented to a private veterinary clinic for evaluation. At 71 d after the initial visit, the cat died with anemia, jaundice, and hypoalbuminemia, and was subjected to autopsy. Grossly, numerous firm masses, 0.5-2.5 cm diameter, were randomly located in the left lobe of the pancreas. Histologic examination revealed that the pancreatic mass consisted of 2 tumor cell types: mostly small round cells with a minority of epithelial cells. The small cells were arranged in nests of various sizes, which were separated by thin fibrous stroma, and had small, round, hyperchromatic nuclei, scant cytoplasm containing argyrophilic granules, and often formed rosettes. The epithelial cells formed luminal structures. Metastases were observed in the liver, greater omentum, and pancreatic, gastric, pulmonary, and mediastinal lymph nodes. Immunohistochemical examination revealed that the small cells were positive for vimentin, neuron-specific enolase, chromogranin A, cytokeratin (CK) AE1/AE3, and trypsin, whereas the epithelial cells were positive for AE1/AE3, trypsin, CK19, and nestin. Ultrastructurally, the small cells contained abundant electron-dense granules, ~200 nm diameter, whereas the epithelial cells had apical microvilli and numerous zymogen granules, ~300 nm diameter. These findings indicated that the tumor was a pancreatic neuroendocrine carcinoma with exocrine differentiation and systemic metastases.

Structural analysis of the fundamental polymer of the sheath constructed by Sphaerotilus natans.

The sheath of Sphaerotilus natans is composed of cysteine-rich peptide and polysaccharide moieties. The polysaccharide was prepared by treating the sheath with hydrazine, and was determined to be a mucopolysaccharide containing beta-D-GlcA, beta-D-Glc, alpha-D-GalN, and beta-D-GalN. To elucidate the structure of the peptide, the sheath was labeled with a thiol-selective fluorogenic reagent, 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole. Enantiomeric determination of the S-derivatized Cys in the fluorescent sheath suggested that it contained L-Cys mainly. Fluorescent cysteinylglycine was detected in the partial acid hydrolysate of the fluorescent sheath. The sheath-degrading enzyme secreted by Paenibacillus koleovorans produced a fluorescent disaccharide-dipeptide composed of GalN, Gly, and N-acetylated Cys from the fluorescent sheath. The disaccharide and dipeptide moieties were found to be connected by an amide bond. Based on these results, the sheath was deduced to be formed by association of a mucopolysaccharide modified with N-acetyl-L-cysteinylglycine.