Chlorinated hydrocarbon insecticides in Colorado beef cattle serum--a pilot environmental monitoring system

A pilot project was initiated to test an existing animal disease surveillance system for use in monitoring environmental pollutants. Eleven chlorinated hydrocarbon insecticides were assayed to provide an indication of environmental contamination. A total of 241 bovine serum samples from 53 Colorado beef ranches was tested; 123 samples (51%) were found to contain detectable concentrations of 1 or more of 11 chlorinated hydrocarbons. There were a total of 203 occurrences of a compound being found at a level exceeding the detection limit. Heptachlor, heptachlor epoxide, lindane, and oxychlordane were the insecticides detected most frequently in bovine sera. This pilot study supports the use of domestic food-producing animals as sentinels of environmental contamination with insecticides.

Investigation of solid-phase ozonolysis reactions for use in a personal sampling method for ozone

Three ozonolysis reactions were tested in the solid phase for reproducibility and quantitative yield of an aldehyde reaction product. The three starting olefins were t-stilbene, 4,4'-dimethoxystilbene and 1,2-di-(4-pyridyl) ethylene which, when reacted with ozone, gave benzaldehyde, p-anisaldehyde and pyridine-4-aldehyde, respectively. The starting olefins were coated on a variety of solid substrates, exposed to known ozone concentrations and then analyzed for the corresponding aldehyde with a gas chromatograph equipped with a flame-ionization detector. The best combination found for all three reactions was with the starting olefin coated on 30/60 mesh Florisil. Consistent yield was obtained for the methoxystilbene reaction within one batch of sorbent; very reproducible results were obtained within four replicate samples for the pyridyl ethylene reaction. No consistency was obtained, however, with any of the reactions between batches of sorbents and between different sets of samples. Several problems were identified which led to the inconsistent results. The t-stilbene and pyridyl ethylene sorbents oxidized over time while stored to form high aldehyde blanks. All three aldehydes, once formed on the sorbent, were volatilized off the sorbent bed as a result of airflow through the bed. Several different solid sorbents were tried unsuccessfully as traps for the purged aldehydes. Finally, lower flow rates resulted in the finding that significant amounts of the aldehydes also were being formed by oxygen in the air sample. Since oxygen was a strong positive interferent, these reactions were considered unacceptable as indicators of ozone.

Colonic myoelectric activity in persons with spinal cord injury

Colonic myoelectric activity was recorded from six para- or quadriplegic subjects with spinal cord injury and seven normal controls via bipolar electrodes in contact with the rectal mucosa. Recordings were carried out in the fasting (basal) state and after stimulation by a standard meal and by 1.0 mg neostigmine intramuscularly. The recordings were visually analyzed for spike activity, average slow wave frequency, and percentage occurrence of subsets of slow wave frequency (2-4 and 5-12 cycles/min). The spinal-cord-injured subjects had significantly more spike wave activity in the basal state than did the controls (12.6 spikes per 10 min vs 3.3). However, meal stimulation did not lead to an increase in spike activity in the spinal-cord-injured subjects (13.7 spikes per 10 min vs 12.6) while it did in the controls (6.4 vs 3.3 spikes per 10 min). Neostigmine significantly increased spike activity in both groups. There was no difference in average slow wave frequency nor any slow wave subsets between the two groups studied. Thus persons with spinal cord injuries have higher basal colonic myoelectric activity than normals but lack a demonstrable gastrocolic reflex. We conclude that the central nervous system exerts a tonic inhibitory influence on basal colonic motility and appears to participate in the gastrocolic reflex.