Abstract-Marinobufagenin and telecinobufagin have been identified as digitalis-like factors in mammals. In toads, marinobufagenin-related compounds, such as marinobufotoxin (MBT), have been isolated in some tissues but not in mammals, and its biological action has not been elucidated. Herein, we aimed to explore the possible production and/or secretion of MBT and the biological action in rats. First, the MBT in culture supernatant of the adrenocortical-originated cell line Y-1 was analyzed by high-performance liquid chromatography and sensitive ELISA for marinobufagenin-like immunoreactivity. Moreover, the structural information was obtained by mass spectrometry. To determine the biological action, MBT (9.6 and 0.96 g/kg per day) was intraperitoneally infused via an osmotic minipump for 1 week. Blood pressure and renal excretion of marinobufagenin-like immunoreactivity were measured. Marinobufagenin-like immunoreactivity was found in Y-1 cell culture media, and the concentration increased until 24 hours. The structural analysis suggested that marinobufagenin-like immunoreactivities were marinobufagenin and MBT, and tandem mass spectrum analysis revealed them with the specific daughter ions. The highest sensitive ELISA-positive peak of marinobufageninlike immunoreactivity in the media was MBT. Continuous administration of MBT in rats for 1 week significantly increased systolic blood pressure and renal excretion of marinobufagenin-like immunoreactivity compared with control rats (135Ϯ3.0 versus 126Ϯ2.0 mm Hg and 1.41Ϯ0.286 versus 0.34Ϯ0.064 ng/day, respectively). These data suggest that MBT, arginine-suberoyl ester of marinobufagenin, can be a novel digitalis-like factor with hypertensive action and is secreted from the adrenocortical cells.

SUMMARYFc g RIII (CD16) is found in two alternative forms, a transmembrane Fc g RIIIa expressed on NK cells and macrophages, and a glycosylphosphatidylinositol-linked Fc g RIIIb present on neutrophils. Previously, we measured soluble Fc g RIIIa (sFc g RIIIa) in plasma of NA(1 + , 2-) phenotyped donors with the anti-Fc g RIII monoclonal antibody (MoAb) GRM1, which recognizes NA2-Fc g RIIIb and Fc g RIIIa. The level of sFc g RIIIa, as well as the total sFc g RIII (sFc g RIIIa plus sFc g RIIIb) in patients with rheumatoid arthritis (RA) was significantly higher than that in healthy controls. In this study, we measured sFc g RIIIa M f in plasma with a newly developed anti-Fc g RIII MoAb, MKGR14 (mIgM), which recognizes Fc g RIIIa M f specifically. From the recovery of purified sFc g RIIIa M f , the amount of sFc g RIIIa M f present was about half that of sFc g RIIIa NK , and that of sFc g RIIIa was about 50 times lower than that of sFc g RIIIb in pooled plasma from healthy NA(1 + , 2-) phenotyped donors. The level of sFc g RIIIa M f in RA patients was about four times higher than that in healthy controls. In RA patients, both the sFc g RIIIa M f and sFc g RIIIa levels were increased as proportionally as the Lansbury Index. The sFc g RIIIa, but not sFc g RIIIa M f levels, were increased directly proportional to C-reactive protein. sFc g RIIIa M f may be a novel marker of disease activity in RA.

Enantioface-differentiating hydrogenations of methyl acetoacetate over (S)-alanine-, (S)-2-aminobutyric acid, (S)-valine-, (S)-leucine-, (S) -malic acid-, and (R,R)-tartaric acid-MRNi were carried out under atmospheric pressure of hydrogen and the effects of the modifying reagent on the rates of the formation of enantiomer, vS and vR, were investigated. The rates of hydrogenation, v=vS+vR, were the same for all the amino acid-MRNi and also for all the hydroxy dicarboxylic acid-MRNi. However, the vR⁄vs ratios were different. These results are explained in terms of the independence of the rate-determining and enantioface-differentiating steps in the reaction pathway of hydrogenation. The rate-determining step of hydrogenation was shown to be the hydrogen addition to the adsorbed substrate, while the enantioface-differentiating step was expected to occur prior to the rate-determining step.

Monoclonal antibody 9B2 possesses hemagglutination inhibition activity against all the 2002/2003 influenza B virus Victoria group isolates in Kobe, Japan, as well as representative strains isolated between 1987 and 1997. The 9B2 epitope localizes three-dimensionally in the vicinity of antigenic site A of the hemagglutinin molecule, and amino acid substitutions in this region affected the binding of 9B2.