Measurement of microdosimetric spectra produced from a 290 MeV/n Spread Out Bragg Peak carbon beam

Radiation and Environmental Biophysics - This study describes measurements on secondary particles produced by a 290 MeV/n Spread Out Bragg Peak (SOBP) carbon beam. Microdosimetric...     

The role of cytochrome b5 in adrenal microsomal steroidogenesis.

The role of cytochrome b5 in adrenal microsomal steroidogenesis was studied in guinea pig adrenal microsomes and also in the liposomal system containing purified cytochrome P-450s and NADPH-cytochrome P-450 reductase. Preincubation of the microsomes with anti-cytochrome b5 immunoglobulin decreased both 17 alpha- and 21-hydroxylase activity in the microsomes. In liposomes containing NADPH-cytochrome P-450 reductase and P-450C21 or P-450(17) alpha,lyase, addition of a small amount of cytochrome b5 stimulated the hydroxylase activity while a large amount of cytochrome b5 suppressed the hydroxylase activity. The effect of cytochrome b5 on the rates of the first electron transfer to P-450C21 in liposome membranes was determined from stopped flow measurements and that of the second electron transfer was estimated from the oxygenated difference spectra in the steady state. It was indicated that a small amount of cytochrome b5 activated the hydroxylase activity by supplying additional second electrons to oxygenated P-450C21 in the liposomes while a large amount of cytochrome b5 might suppress the activity through the interferences in the interaction between the reductase and P-450C21.     

Molecular and immunochemical characteristics of monoclonal and recombinant antibodies specific to bisphenol A

Four anti-bisphenol A monoclonal antibodies (mabs) were obtained and each characterized by an enzyme-linked immunosorbent assay (ELISA). Among these mabs, BBA-2187 was the most reactive towards bisphenol A. The quantitation limit of the ELISA assay for bisphenol A was 0.13 ng/ml, which is more sensitive than the other immunoassays reported. Then, the cDNA clones encoding variable heavy and variable light chains of these four mabs were isolated, and used for construction of four single-chain Fv (scFv) antibody genes, which were expressed in Escherichia coli cells. The reactivity of four scFv antibodies towards bisphenol A in ELISA was comparable to those of the parent mabs. The most sensitive assay was achieved with BBA-2187scFv. Its cross-reactivity to the related compounds was similar to that of the parent mab. Based on the reactivity of heterologous combinations of VH and VL fragments, it was found that the unique structure of the framework region 2 in the VL of BBA-2187 appeared to be important for specific assembly together with the VH.