B-transferase with a Pro234Ser substitution acquires AB-transferase activity.

A/B-Transferase is a glycosyltransferase that transfers a sugar substrate onto H-antigen, which is responsible for the synthesis of glycoprotein- and glycolipid-conjugates termed A/B-antigens. One polymorphism that causes the Pro234Ser substitution in B-transferase was recently found in a genotyping study, and might be cis-AB. In the present study, we analyzed the phenotypes arising from the enzymatic specificity of B-transferase with the Pro234Ser mutation. To evaluate the effect of the P234S mutation on enzymatic specificity, we generated an expression plasmid for B-transferase with Pro234Ser as well as A-transferase with Leu266Met, which is frequently found in cis-ABs. Transfection of B-transferase/P234S or A-transferase/L266M cDNA into HeLa cells, an O-blood group cell line, resulted in an AB-phenotype by absorption-elution testing and immunostaining, whereas A- and B-transferase-expressing HeLa cells exhibited only their own activity. Molecular simulation indicated that the P234S mutation causes a conformational change in the substrate pocket making it suitable for N-acetylgalactosamine.

Establishment of a simple detection system for blood group ABO-specific transferase activity in DNA-transfected cells.

A/B-transferase is a glycosyltransferase that transfers a sugar substrate onto H-antigen resulting in the synthesis of glycoproteins and glycolipids termed A/B-antigens. The ABO blood group (ABO) gene encoding A/B-transferase possesses numerous polymorphisms affecting the specificity and/or activity of the enzyme. The relationship between genotype and phenotype is very complicated, except for those of some critical polymorphisms. In order to establish a system for evaluating the effect of each polymorphism on the transferase function, an A- or B-transferase cDNA expressing vector was introduced into HeLa cells, a cell line that do not possess endogenous A/B-transferase activity. We successfully detected substrate-specific transferase activity in the cells and in the culture medium. Furthermore, in three different assays, each corresponding A- or B-antigen was detected in the transfectants with high sensitivity. Accordingly, the present study demonstrates a possibility that A/B-transferase variants may be characterized by using this method.

Evaluation of urinary CA19-9 levels in bladder cancer patients classified according to the combinations of Lewis and Secretor blood group genotypes.

OBJECTIVES: This study evaluated the clinical significance of urinary CA19-9 levels in bladder cancer patients classified according to various combinations of Lewis (Le) and Secretor (Se) genotypes. METHODS: Urinary CA19-9 and DU-PAN-2 levels were measured as units per mg creatinine (U/mg Cr) in 121 patients with bladder cancer and in 31 patients with other urologic diseases. Genotyping was carried out using polymerase chain reaction-based methods. RESULTS: Urinary CA19-9-values in patients with both Le and Se alleles (Le/Le, Se/Se; Le/Le, Se/se; Le/le, Se/Se; Le/le, Se/se) were significantly higher (P < 0.0001) in bladder cancer cases compared to the other urologic diseases. The cut-off value determined using receiver operating characteristics analyses was 37.6 U/mg Cr. Approximately 70% (57/87) of bladder cancer patients with both Le and Se alleles demonstrated urinary CA19-9 levels over the cut-off value. In contrast, only 16% (4/24) of patients with other urologic diseases were over the cut-off value. CONCLUSIONS: The urinary CA19-9 level can be a new effective diagnostic tool in bladder cancer patients with both Le and Se alleles.

Embryonal carcinoma producing DU-PAN-2 with burned-out phenomenon in the testis.

A burned-out testicular tumor with lung and lymph node metastases presented high serum levels of DU-PAN-2. However, the serum levels of CA19-9, alpha-fetoprotein, beta-human chorionic gonadotropin, and sialyl Lewis X were normal. A biopsy of the cervical lymph nodes revealed embryonal carcinoma. Four courses of chemotherapy, including cisplatin, etoposide, and bleomycin, normalized the level of DU-PAN-2, and the metastatic lesions disappeared. This is the second reported case of an embryonal carcinoma producing DU-PAN-2. The secretor and Lewis gene typings, which affect the normal serum ranges of CA19-9 and DU-PAN-2, were determined.

A case of intramuscular cysticercosis diagnosed definitively by mitochondrial DNA analysis of extremely calcified cysts.

A case of obsolete intramuscular cysticercosis diagnosed definitively by mitochondrial DNA analysis of extremely calcified cysts was reported. X-ray and computed tomography findings highly suggested cysticercosis due to Taenia solium; however, no direct evidence of cysticercosis was obtained through serological or histopathological examinations. Mitochondrial DNA analysis of a histopathological specimen confirmed the causative agent to be the Asian genotype of T. solium.