Esophageal squamous cell carcinoma characterized by extensive chondroid differentiation.

A rare case of carcinoma characterized by extensive chondroid elements at a site of primary esophageal and metastatic lesion is reported. The patient was a 67-year-old man complaining of dysphagia due to an ulcerative lesion at the lower middle esophagus. He underwent irradiation treatment prior to surgery. Histologically, the tumor consisted of both carcinomatous and chondroid elements and had invaded deeply into the esophageal wall. The carcinomatous cells had gradually become chondroid cells embedded within an extensive extracellular matrix. In addition, the metastatic lesion showed findings similar to those of the primary lesion. Immunohistochemistry revealed that both carcinomatous and chondroid elements were immunostained with cytokeratin and epithelial membrane antigen, suggesting an epithelial nature to the chondroid cells. Conversely, only chondroid cells were positively stained for S-100 protein. Furthermore, bone morphogenetic proteins (BMP) were positive for chondroid cells and their surrounding carcinomatous cells. Given the apparent transition between carcinomatous and chondroid cells based on microscopy and immunohistochemical findings in the present case, we concluded that the chondroid cells were derived from carcinomatous cells. In addition, our findings suggest that BMP produced by carcinomatous cells lead to chondroid differentiation of the carcinoma cells.

Identification of a novel amino acid, o-bromo-L-phenylalanine, in egg-associated peptides that activate spermatozoa.

Eight sperm-activating peptides containing a novel amino acid were isolated from the egg jelly of the sea urchin Tripneustes gratilla. Accurate mass measurement of the peptide in FAB mass spectrometry showed that the mass of the novel amino acid residue was 224.978. On the basis of the isotopic ion distribution and the degree of unsaturation, the mass value indicated that the elemental composition of the amino acid residue was C9H8O1N1Br1, suggesting that the novel amino acid was bromophenylalanine. Proton NMR spectroscopy, amino acid analysis, and RP-HPLC with three synthetic isomers of bromophenylalanine demonstrated that o-bromophenylalanine was the novel amino acid. Derivatization of the amino acid with Marfey's reagent, (1-fluoro-2,4-dinitrophen-5-yl)-L-alanine amide (FDAA), further indicated that the amino acid was the L-isomer. In other sperm-activating peptides isolated from the egg jelly of the sea urchin, both m- and p-bromophenylalanines were discovered. The presence of m-bromophenylalanine has not been previously reported in natural products, while p-bromophenylalanine is found in theonellamide F, an antifungal bicyclic peptide from a marine sponge.

Haemichrome formation from haemoglobin subunits by hydrogen peroxide.

The effect of H2O2 on ferrous human haemoglobin subunits (alphash-, betash-, alphapmb- and betapmb-chains) was studied. These chains were easily transformed to haemichrome by the addition of H2O2 or H2O2-generating systems, including glucose oxidase (EC 1.1.3.4) AND XANTHINE OXIDASE (EC 1.2.3.2), and this was ascertained by e.p.r. measurements and by absorption spectra. The changes in these haemoglobin subunits were not inhibited by superoxide dismutase (EC 1.15.1.1), but were decreased by catalase (EC 1.11.1.6). The rate of oxidation of alphapmb-chains was higher than that of alphash-chains, and the rate of oxidation of betapmb-chains was higher than that of betash-chains. Haemichrome was demonstrated to be formed directly from these ferrous chains by the attack by H2O2, and this process did not involve formation of methaemoglobin. On the basis of these findings the kinetics of the reaction between the haemoglobin subunits and H2O2 was studied, and the pathological significance of H2O2 in disorders of erythrocytes such as thalassaemia was discussed.