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Biomedical subjects

J P Boon

Publications and source records attributed to J P Boon.

23 records · Page 2Linked to original sources
PubMed1984

Kinetics of individual polychlorinated biphenyl (PCB) components in juvenile sole (Solea solea) in relation to their concentrations in food and to lipid metabolism.

PCBs were administered to juvenile soles (Solea solea) with food. Homogenates of gut, liver, brain, dark skin, muscle and gills were analysed for their contents of individual PCB components. The relative contributions of individual components to total PCB were virtually identical in the various organs sampled at the same day in a 275-day period. During the experiment concentrations on a (pentane-extractable) lipid basis of most PCB components declined in all organs regardless of lipid metabolism. The results suggest that PCB patterns in organs are determined by equilibrium partitioning. So components remained mobilizable from organs whose lipid contents increased. This is in contrast with the idea that PCBs are taken up and stored in lipids under circumstances of increasing lipid content in organs. The plateau-values of the steady-states of lipid based concentrations of PCB components decreased in all organs. This might have been due to changes in lipid contents or lipid composition in some organs.

Animal Feed↗
PubMed1974

Light-scattering spectrum due to wiggling motions of bacteria.

Simple models are used to calculate the inelastic light scattering spectrum of motile bacteria when wiggling motions are included in addition to translational displacement. Computations of spectra lead to the conclusion that nontranslational motions can be neglected when swimming speeds are deduced from light-scattering data for normal vigorously motile strains. On the other hand, for slowly translating bacteria, or for strains exhibiting noticeable wiggling motion when viewed in a microscope, additional spectral components may be significant. Such components are best distinguished when measurements are made at small and intermediate scattering angles; at large angles the spectra have approximately the same scaling properties (functionals of Qt, Q being the Bragg wave vector) as those associated with simple translational motility.

Bacteria↗
PubMedDate not supplied

The expression of CYP1A, vitellogenin and zona radiata proteins in Atlantic salmon (Salmo salar) after oral dosing with two commercial PBDE flame retardant mixtures: absence of short-term responses.

The short-term effects of the commercial PBDE flame retardant mixtures Penta-BDE and cta-BDE on the expression of cytochrome P450 1A (CYP1A), vitellogenin (Vtg) and zona radiata proteins (Zrp) were investigated in juvenile salmon (Salmo salar). For this purpose, groups of fish were dosed twice (oral intake at days I and 4) with 10 and 50 mg/kg body weight of both commercial mixtures. The fishes were sacrificed at day 7 (n = 5 for each group) and 14 (n = 6 for each group), and blood, liver, fillet, and brain were collected. Blanks and positive controls were also part of the experiment. The expressions of Vtg, Zrp, and CYPIA were measured with several techniques (EROD, ELISA, Western, Northern and Slot Blot). The values in the groups of fish treated with Penta-BDE or Octa-BDE did not significantly differ from the reference group for any of the parameters tested. In contrast, the positive control groups treated with estradiol-17beta for Vtg and Zrp expression, and beta-naphthoflavone for CYP1A expression did show a significant response, indicating the potential sensitivity of the fishes for the parameters measured. Since the results of the chemical analyses showed concentrations of a number of PBDE congeners in liver, fillet, and brain that were about three orders of magnitude above those of fish from the North Sea, it is concluded that the short-term toxicity of both commercial PBDE mixtures for these endpoints was low.

Administration, Oral↗
PubMedDate not supplied

Cytochrome P450 differences in normal and imposex-affected female whelk Buccinum undatum from the open North Sea.

Normal and imposex-affected female Buccinum undatum were sampled from the open North Sea at three locations, one with low, and two with high shipping densities. Cytochrome P450 components and P450 aromatase activity were determined in the microsomal fractions isolated from pooled digestive gland/gonads. Cytochrome P450 aromatase activity was significantly higher (P < 0.05) in normal females collected in the low shipping density area (1,325 +/- 295 fmol/h/mg protein) than levels from imposex animals from a high shipping density area (620 +/- 287 fmol/h/mg protein). A negative correlation was found between aromatase activity and organotin body burden (r = -0.99). Levels of CYP450, cytochrome b5 and NADPH cytochrome c reductase activity did not show differences among groups. This is the first field evidence of depressed aromatase activity in imposex affected females, although additional research under laboratory controlled conditions is required to fully understand the mechanisms underlying the development of imposex in this species.

Animals↗