A mouse IgG1 monoclonal antibody (MAb), 19A211, defining a tumor-associated cell-surface antigen of superficial papillary bladder tumors, was generated by immunizing with fresh bladder tumor cells mice neonatally injected with normal human urothelial cells. The reactivity of the antibody with cell lines was examined by indirect immunofluorescence staining and was restricted to 3/14 bladder cancer lines and 3/31 cancer cell lines of non-bladder origin, including HeLa cervical cancer. No normal fibroblast, kidney cells, EBV-lymphocytes, erythrocytes or leukocytes expressed the antigen. Reactivity of MAb 19A211 was well preserved on tissue paraffin sections. Immunoperoxidase staining of normal adult or fetal tissues showed no reactivity except for a patchy or uniform staining of umbrella cells in 6/23 adult and 1/4 fetal urothelium samples. Positive and often heterogeneous staining was observed on 24/38 papillary superficial tumors (Ta) and 4/5 carcinoma in situ bladder lesions but on only 4/20 infiltrating tumors. It was also observed on 5/6 cervical condylomas and one bladder condyloma, but none of 6 penile or vulvar condylomas. All other tumors tested were negative. The antigenic determinant is present on a heterogeneous group of proteins with molecular weights ranging from 90 to 200 kDa. It is sensitive to periodate treatment and to neuraminidase but only partially sensitive to proteases. MAb 19A211 is different from other reported MAbs with similar reactivity to superficial bladder tumors and umbrella cells of normal urothelium. When tested in competition assays, several of these MAbs, but not 19A211, were found to react with Lewis X blood group determinant. Our results suggest that 19A211 may be useful for detection and stratification of bladder tumors.
another study of NDP-kinase isolated from calf thymus, Nakamura and Sugino (1966) separated two peaks of NDPkinase activity by chromatography on DEAE-cellulose at pH 7.5. These fractions could not be distinguished from each other with respect to their specificity toward nucleoside triphosphates, optimal pH, and metal requirements, but sucrose density gradient centrifugation suggested the presence of at least two forms of enzyme with different sedimentation rates. The recent studies of Edlund et ai. suggest the possible occurrence of isozymes of NDP-kinase in baker's yeast since phosphocellulose chromatography separated one main activity peak preceded by a small one. In some preparations the two activity peaks were of nearly the same size. However, to our knowledge there has not been a clear-cut demonstration of isozymes of NDP-kinase prior to the present report. Acknowledgment ABSTRACT: In the course of this work, two lines of evidence were obtained consistent with the view that a histidine residue participates in the active site of porcine pancreatic lipase. (1) The maximal rate of lipase-catalyzed hydrolysis of tributyrin emulsions is under the control of an ionizable group of pK = 5.8 which must be unprotonated. The parallel variation cf K,,, and V , in this pH range has been interpreted as showing
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