Nine cases of granular cell tumors in B6C3F1 mice.

The histological characteristics of 9 cases of granular cell tumors (GCTs) observed in B6C3F1 mice were examined to determine their cellular origin. Seven of the 9 cases were found in the uterus and other 2 cases were in the subcutaneous tissue. Tumor cells had abundant granules in the cytoplasm which were stained with PAS and were resistant to diastase treatment. Ultrastructurally, the granules were identified as lysosomes. The cell surface had cytoplasmic processus showing interdigitation with adjacent cells. A character feature of the tumor cells was the presence of a desmosome-like structure on their cell surface but no basal lamina was demonstrated. Although GCTs have been considered to be derived from Schwann cells on the basis of their ultrastructural features and S-100 protein-immunopositive findings, the absence of basal lamina in the present cases may raise a controversy as to their origin.

Morphogenesis of craniopharyngeal derivatives in the neurohypophysis of Fisher 344 rats: abnormally developed epithelial tissues including parotid glands derived from the stomatodeum.

Morphogenesis of craniopharyngeal derivatives of the neurohypophysis found in 14 Fischer 344 (F344) rats was studied. The incidence of the craniopharyngeal derivatives was 0.17% in male (7 out of 4,200) and 0.16% in female (7 out of 4,450) F344 rats. Neither a sex-related difference in their incidence nor a strain-related difference in their morphological features was observed. Craniopharyngeal derivatives were composed of aberrant epithelial structures consisting of serous acinar and tubular and fusiform cell structures, and most of these derivatives were associated with Rathke's cleft cysts, which are suggestive of a congenital background. The acinar structures were positive for periodic acid-Schiff reaction and negative for Alcian blue stain. Immunohistochemically, cells forming these structures were positive for cytokeratin, and basal cells of the acinar or tubular structures and some of the fusiform cells showed positive staining for alpha-smooth muscle actin. Electron microscopically, these spindle-shaped basal cells had intracytoplasmic myofilaments with focal density in their cytoplasm, and they were regarded to be myoepithelial cells. These findings strongly indicate that the craniopharyngeal derivatives are not a neoplastic lesion but rather are a developmental aberration derived from the stomatodeum, which is known to be the origin of both nasal and oral epithelial tissues, including the parotid glands, other than Rathke's pouch.

A congenital ciliated epithelial cyst on the stomach of a B6C3F1 mouse.

Congenital anomalies of the alimentary tract are rare lesions in laboratory animals. We describe a congenital cyst attached to the greater curvature of the forestomach in a B6C3F1 mouse. The inner surface of the cyst was mostly covered with cuboidal or pseudostratified ciliated epithelium and was focally covered with the flat cuboidal epithelium. The base of the cyst appeared to be inserted between the layers of the outer longitudinal muscle layer of the forestomach, although no smooth muscle layer was evident in the free surface of the cyst wall. The cyst resembled duplication of the alimentary tract, as it was lined with ciliated epithelium and had developed at the greater curvature of the forestomach. Since the smooth muscle layer did not completely cover the whole wall and the cyst did not communicate with the gastric lumen, the cyst was not thought to be a standard duplication but rather a simple congenital cyst.

Eosinophilic granulated cells comprising a tumor in a Fischer rat.

A systemic tumor developed in multiple organs, including spleen, bone marrow, lymph nodes, liver, ovaries, and thoracic and lumbar vertebrae, of a female F344Du/Crj rat. The tumor was composed of round to indented mononuclear cells containing abundant large eosinophilic granules in the cytoplasm. The peripheral blood smear revealed that the large granules in the cytoplasm of the tumor cells were stained basophilic with Giemsa, suggesting a basophil or mast cell origin. However, these granules did not show metachromasia with toluidine blue and were stained blue to dark blue with phosphotungstic acid hematoxylin. Cellular morphology and characteristics in the specific stains of tumor cells suggested the development of a tumor of globule leukocytes in a F344Du/Crj rat.

Flavor characteristics of glutathione in raw and cooked foodstuffs.

The flavor of glutathione (gamma-L-glutamyl-L-cysteinylglycine, GSH) was examined by several sensory evaluations. The measurement of a point of subjective equality (PSE) showed that the peptide increases the flavor characteristics but did not affect the intensity of basic tastes, such as sweetness, saltiness, sourness, and umami. However, the threshold value of GSH decreased significantly in an umami solution containing 0.05% each of monosodium glutamate (MSG) and disodium inosinate (IMP). This suggests that GSH interacts with the umami substance and has a certain effect on the flavor. GSH had a characteristic kokumi flavor, such as continuity, mouthfulness, and thickness in the umami solution as well as in a model beef extract constructed from analyzed components at a concentration of 0.02% w/v. Some foodstuffs, including meat, were found to contain GSH above its threshold value, which implicates the contribution of GSH to the flavor. The thermal degradation study suggested that a part of GSH have changed into its disulfide, pyroglutamic acid (PCA), and cyclocysteinylglycine in cooked foodstuffs.

Composition of Sulfur-Containing Components in Onion and Their Flavor Characters.

Sulfur-containing components in an ethanol extract and boiled water extract of onion (Allium cepa L.) were analyzed by HPLC. Trans-(+)-S-propenyl-l-cysteine sulfoxide (PeCSO) and its γ-glutamyl peptide (γ-Glu-PeCSO) were the major constituents in the ethanol extract, whereas cycloalliin was the most abundant one in the boiled water extract. The large amount of cycloalliin found in the boiled water extract was mostly derived from PeCSO by heating. PeCSO and γ-Glu-PeCSO showed a characteristic kokumi flavor (continuity, thickness, and mouthfulness) by a sensory test in an umami solution containing 0.05% (w/v) each of monosodium glutamate and disodium inosinate.