Exposure to trihalomethanes and adverse pregnancy outcomes.

Exposure during pregnancy to disinfection by-products in drinking water has been hypothesized to lead to several adverse reproductive outcomes. We performed a retrospective cohort study to examine the relation of trihalomethane exposure during the third trimester of pregnancy to low birthweight, term low birthweight, and preterm delivery. We matched Colorado birth certificates from January 1, 1990, through December 31, 1993, to historical water sample data with respect to time and location of maternal residence based on census block groups. After excluding births from all census block groups with no trihalomethane sample data and restricting to singleton white births with 28-42 weeks of completed gestation (>400 gm), we studied 1,893 livebirths within 28 census block groups. We found a weak association of trihalomethane exposure during the third trimester with low birthweight (odds ratio = 2.1 for the highest exposure level; 95% confidence interval = 1.0-4.8); a large increase in risk for term low birthweight at the highest level of exposure (odds ratio = 5.9; 95% confidence interval = 2.0-17.0); and no association between exposure and preterm delivery (odds ratio = 1.0 for the highest exposure level; 95% confidence interval = 0.3-2.8). The small number of adverse outcomes reduced the precision of risk estimates, but these data indicate a potentially important relation between third trimester exposure to trihalomethanes and retarded fetal growth.

An evaluation of an ambulatory manometry system in assessment of antroduodenal motor activity.

While abnormalities in antroduodenal motor function have been documented in both organic and "functional" disorders, controversy surrounds the ideal manometric technique. We sought, therefore, to evaluate a digital solid-state ambulatory system. Sixteen normal volunteers underwent 24-hr recordings of antroduodenal motility. Following catheter placement, a standardized meal was ingested in the laboratory; thereafter, subjects were ambulatory and assumed normal diet and activities. The system was well tolerated; subjects reported that it did not affect their usual activities. Migrating motor complex (MMC) activity was identified in each subject (mean frequency: 4.1 MMCs/24 hr, range 1-8); on average 1.9 (range 0-4, frequency 0.1/hr) occurred while awake and 2.1 (range 0-5, 0.3/hr, P < 0.05 vs awake) during sleep. The fed response was evaluated by calculating a motility index (MI) at 30-min intervals from 30 min before to 120 min following meal ingestion. Postprandially, MI was maximal during the first 30 min following meal ingestion: MI (mean +/- SD) 30 min before vs 30 min after meal in the antrum: 4.16 +/- 1.42 vs 5.33 +/- 0.72 (P < 0.05), duodenum: 4.04 +/- 0.80 vs 4.57 +/- 0.47 (P < 0.05), respectively. None of the other postprandial intervals were significantly different from baseline. There was no significant difference in MI between the standard and ad libitum meals. Retrograde catheter migration (mean 5.6, range 1-10 cm) occurred in relation to all meals: as a consequence, antral recordings were lost following 60% of all meals, thereby limiting meaningful analysis of the antral fed response. We conclude, firstly, that while an ambulatory antroduodenal manometry system is well tolerated and reliably records duodenal motility, postprandial catheter migration limits antral recordings, and, secondly, that a motility index calculated during the first 30 min following an ad libitum meal accurately reflects the fed motor response.

Blisters, pruritus, and fever after bites by the Arabian tick Ornithodoros (Alectorobius) muesebecki.

A biologist was bitten by Ornithodoros (Alectorobius) muesebecki Hoogstraal, an endemic tick parasite of nesting and resting marine birds on islands in eastern Arabia. Irritating bullae developed and for four months he experienced intermittent inflammation and irritation. Two years earlier, after being bitten by the same tick species on a different island, he had experienced only irritation lasting no more than a fortnight. Petroleum-industry labourers on another island were admitted to hospital for about two weeks with bullae at numerous bite sites, intense pruritus, headache, and fever. Zirqu virus (Bunyaviridae, Nairovirus) has been isolated from O. (A.) muesebecki samples from Abu Dhabi. The role of Zirqa virus and/or of salivary toxins in producing irritation and illness, as well as individual sensitivity to the tick and the seasonal dynamics of toxicity or infectivity, should be investigated.