Hitoshi Kawasaki

Determination of the reducing terminal sugars of glycosaminoglycans using 2-aminopyridine.

The fluorescence labeling method (Takemoto, H. et al. (1985) Anal. Biochem. 145, 245-250) has been shown to have high sensitivity for measuring the sugar composition of glycoproteins. In the present study, its applicability for analysis of the reducing terminal sugars of glycosaminoglycans was investigated. The procedure involved coupling of glycosaminoglycans with 2-aminopyridine, followed by hydrolysis and N-acetylation, and then analysis by high-performance liquid chromatography on a reverse-phase column. The method was found to be useful for simultaneous determination of acidic, neutral and amino sugars at the reducing termini of glycosaminoglycan moieties.

Carcinosarcoma of the esophagus producing granulocyte-colony stimulating factor: report of a case

A 51-year-old man was admitted to the hospital for dysphagia, pyrexia, and leukocytosis. The serum level of granulocyte-colony stimulating factor (G-CSF) was elevated. Barium esophagography and endoscopy revealed a polypoid tumor in the middle portion of the esophagus. After an esophagectomy, the leukocyte count and serum G-CSF level normalized. The pathological diagnosis was carcinosarcoma of the esophagus with two components: namely, squamous cell carcinoma and sarcoma. Moreover, cancer cells were positive for G-CSF antibody. These findings confirmed that the esophageal carcinosarcoma in this case was a G-CSF-producing tumor. Although a G-CSF-producing esophageal carcinosarcoma is very rare, this disease should be considered when a patient has symptoms such as leukocytosis and pyrexia without an associated infection.

Preparation and application of a fluorogenic substrate for endo-β-xylosidase

The present paper describes a fluorometric assay for galactosaminoglycan-degrading endo-beta-xylosidase, utilizing glycosaminoglycan chains bearing a 4-methylumbelliferyl group at the reducing terminus as a substrate. This fluorogenic substrate is synthesized by human skin fibroblasts cultured in the presence of a fluorogenic xyloside, 4-methylumbelliferyl-beta-D-xyloside. The assay is based on measurement of the fluorescence of 4-methylumbelliferone, enzymatically liberated from the synthetic substrate by endo-beta-xylosidase. We examined the applicability of the assay for analysis of endo-beta-xylosidase activity.

Presence of an endo-β-galactosidase degrading the linkage region between the chondroitin sulfate chain and core peptide of proteoglycan

Pyridylamino chondroitin sulfate, of which the reducing terminal xylose was coupled with a fluorescent 2-aminopyridine, was incubated at pH 4.0 with an extract from the mid-gut gland of Patnopecten. The high- and low-molecular-weight products were separated by ethanol precipitation, and identified by high-performance liquid chromatography analysis. The enzyme was found to expose a galactose residue at the reducing terminus of chondroitin sulfate, and also released the pyridylamino disaccharide, galactosylxylose, from the reducing terminal site of pyridylamino chondroitin sulfate. These results suggest that endo-beta-galactosidase activity, which hydrolyzes the galactosylgalactose linkage of peptidochondroitin sulfate, is present in the mid-gut gland of Patnopecten.

Enzymic determination of acidic glycoconjugates in human pancreatic juice

SummaryAcidic glycoconjugates (glycosaminoglycans, sulfated glycopeptide, and sialoglycopeptide) were isolated by precipitation with cetylpyridinium chloride from human pancreatic juice after digestion with pronase. The acidic glycoconjugates were found exclusively in the proteinaceous precipitate that occurred during dialysis against a buffer of low ionic strength. The concentration of the acidic glycoconjugates in normal pancreatic juice was about 2.4 mg/L. The acidic glycoconjugates were characterized by electrophoresis on cellulose acetate membrane and chemical analysis before and after digestion withStreptomyces hyaluronidase, chondroitinase AC, chondroitinase ABC, and heparitinase. It was found that the major acidic glycoconjugates were heparan sulfate (39.3%), sulfated glycopeptide (34.4%), chondroitin sulfate (14.2%), and the minor ones hyaluronic acid (6.4%) and sialoglycopeptide (5.7%).