Mirex-induced hepatic changes in chickens, Japanese quail, and rats

Mirex was fed in the diet to chickens at 0 to 160 ppm for 12 and 16 weeks, to Japanese quail at 0 to 80 ppm for 12 weeks, and to rats at 0 to 100 ppm for 2 and 4 weeks. Mirex did not affect the concentration of protein or cytochrome P450 in hepatic microsomes of chickens or Japanese quail, nor did it affect hydroxylation of aniline or demethylation of aminopyrine. However, structural changes were apparent in livers of chickens fed mirex at 10 ppm and above and included regions of necrosis and nonspecific cellular aberrations and alterations of sinusoids and bile canaliculi. Mirex caused liver enlargement in rats and increased microsomal protein and cytochrome P450 but did not affect hydroxylation of aniline or demethylation of aminopyrine. Hepatic structural changes in rats that were associated with mirex included proliferation of smooth endoplasmic reticulum and degeneration of some bile canaliculi.     

Editorial

Soft X-ray (2.05–4.4nm) contact microscopy, using synchrotron radiation, of ultrasections of lead-polluted chloragogenous tissue of the earthworm Dendrobaena rubida has been achieved. The positive resist, after etching to leave areas corresponding to high absorbance in the tissue, is viewed by SEM and the imaging compared with the same section viewed, after irradiation, by TEM. No radiation damage as evident and the lead deposits associated with the chloragosomes and within the debris vesicles imaged clearly. The characteristics of the broad beam have thus produced a lead ‘map’. Resolution is in the order of 70 nm. The results are compared with the markedly different imaging of control tissue containing insignificant lead levels.     

Some ionospheric factors affecting the coverage of an HF/VHF direct broadcasting satellite service

A study has been undertaken to assess the effects of the ionosphere on the performance of a direct broadcasting satellite service operating in the high frequency (HF) band. Results relating to two issues of performance are presented: 1) determining under what conditions a frequency allocated to the broadcasting service can be expected to reach the surface of the earth from a satellite and 2) the loss of signal strength due to passage through the ionosphere, it was found that if high frequency broadcast services are to be provided on a worldwide basis using satellite platforms, the satellites need to be optimally configured for the intended service area. Also, a 3 dB loss of signal strength is expected due to ionospheric absorption.     

The performance of children with auditory perceptual disorders on a time-compressed speech discrimination measure

A time-compressed version of the PB-K 50 speech discrimination measure was administered to 20 children diagnosed as displaying auditory perceptual disorders. Results indicated that these children performed equally well at both 0 and 30% time compression. Performance decreased significantly at 60% time compression. Comparison of the results with normative data indicated that performance of the two groups of children was similar at the 30% time compression condition but that children with auditory perceptual disorders performed poorer at both 0 and 60% time compression. The results were discussed relative to short-term memory abilities.     

Application of a Muscle-Potential Monitor to Electroconvulsive Therapy

A battery-operated IC amplifier converts muscle potentials to audio signals. It has been successfully used clinically to monitor patients undergoing electroconvulsive therapy for evidence of muscle relaxation, duration, and bilaterality of response.