Changes in creatine kinase and its isoenzymes in human fetal muscle during development.

The total creatine kinase activity and its isoenzyme patterns were investigated in the skeletal muscle of 87 fetuses, of which 80 were presumed normal, 5 were anencephalic and 2 were "at risk" for Duchenne muscular dystrophy (DMD). No differences, either in total enzyme activity or in the isoenzyme distributions, were found between the anencephalic fetuses or those at risk for DMD, when compared to normal fetuses of similar gestation. Creatine kinase activity was found to rise steadily throughout embryonic life. During fetal development, the isoenzyme pattern in skeletal muscle was observed to change from the initial prevalence of the brain (BB) type, to the predominance of the muscle (MM) form. The most pronounced change occurred between the 6th and the 16th week of gestation, a period characterized by the rapid fusion of myoblasts to form myotubes and the concomitant production of myofibrils. It is proposed that there is a close association between the creatine kinase isoenzymes spectrum and the stage of muscle development.

Validation of a congener specific method for ortho and non-ortho substituted polychlorinated biphenyls in fruit and vegetable samples.

An on-line procedure has been developed and validated for the clean-up and fractionation of ortho and non-ortho-PCBs in fruit and vegetable samples. The procedure combines silica/acid and carbon/glass fibre columns with gas chromatography-mass spectrometry. Chromatography on carbon/glass fibre allowed collection of mono-ortho/di-ortho and non-ortho-PCB fractions, which were determined separately by GC-MS. The method was validated by replicate analyses and by inter-laboratory comparison of data for PCB congeners determined in fruit and vegetable samples collected in South Wales. The concurrent determination of ortho and non-ortho substituted PCBs is reported with recoveries ranging from 55-95% and a mean intra-laboratory precision (%COV) of 9.5% for apple extracts.

PCB and PCDD/DF concentrations in egg and poultry meat samples from known urban and rural locations in Wales and England.

A survey was undertaken of PCB and PCDD/DF congeners in eggs and poultry meat from a smallholding close to a chemical waste incinerator, other sites in the surrounding district, and three rural locations. The concentrations from the site close to the incinerator were appreciably greater than those found elsewhere, although the contrast was less marked for poultry meat than eggs. All types of poultry produce displayed noticeable variations in congener composition when the samples were grouped according to geographical origin. These results support the view that the environment in which poultry live does influence the PCB and PCDD/DF characteristics of their products. Exposure calculations indicated that consumption of eggs from the site close to the incinerator would constitute a substantial proportion of recommended daily intakes for such contaminants and at the present time these products are not being eaten.

PCB and PCDD/DF congeners in locally grown fruit and vegetable samples in Wales and England.

A survey was undertaken of PCB and PCDD/DF congeners in fruit and vegetables grown in an urban areas close to a chemical waste incinerator and three rural locations. All of the concentrations detected were low and there was considerable overlap between those found in urban and rural samples. Some similarities with the congener composition of air samples were identified and concentrations in apple skin were noticeably higher than those in the flesh of the fruit. These results suggest that atmospheric deposition was an important contamination pathway. Assessments using the highest concentrations found indicated that consumption of such fruit and vegetables would represent an additional 3% of the normal dietary intake for PCBs and 8% for PCDD/DFs.