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D C Logan

Publications and source records attributed to D C Logan.

7 recordsLinked to original sources
PubMed1995

Effect of algal food concentration on toxicity of two agricultural pesticides to Daphnia carinata.

The effects of algal concentration (Selanastrum capricornatum) on the toxicity of the organochlorine pesticide endosulfan and the synthetic pyrethroid esfenvalerate to Daphnia carinata was investigated. The study progressed through four stages: (1) A dose-response experiment on the effects of endosulfan and esfenvalerate on the survival, growth, and reproduction of D. carinata at a single nonlimiting food level. (2) An experiment to investigate the effects of five different food concentrations on survival, growth, and reproduction of D. carinata at sublethal concentrations of endosulfan and esfenvalerate compared with nonexposed controls. (3) An experiment to investigate the effects of route of exposure (water, food-borne, or water+food-borne exposure) on the toxicity of endosulfan to D. carinata. (4) An experiment to investigate the effects of algal concentration on persistence of endosulfan in the water column and on the relative toxicity of the alpha and beta isomers and of endosulfan sulfate to D. carinata. In the first experiment all daphnids exposed to 500 ng/liter esfenvalerate died within 3 days. There was a significant effect of esfenvalerate on reproduction at 50 ng/liter by the second brood. Endosulfan did not cause significant mortality to daphnids but brood size was reduced at 320 micrograms/liter. In the second experiment the toxicity of esfenvalerate increased significantly with decreasing food concentration. In contrast, the toxicity of endosulfan to D. carinata was greatest at the higher food concentrations. Direct water-borne exposure to endosulfan was the most toxic route of exposure and the presence of algae decreased toxicity of this pesticide. The total amount of endosulfan (alpha + beta + endosulfan sulfate) persisting in the water column after 24 hr was greater at high food levels, suggesting that this may be one mechanism for increased toxicity at high food concentrations. The 48-hr LC50s of technical endosulfan, endosulfan sulfate, alpha-endosulfan, beta-endosulfan, and a 50:50 mixture of alpha, and beta endosulfan were 478, 756, 249, 205, and 234 micrograms/liter, respectively.

Analysis of Variance↗
PubMed1983

Pentachlorophenol poisoning.

Pentachlorophenol (PCP) is a pesticide commonly used as a wood preservative. Although exposure has been well controlled in large chemical manufacturing plants, over-exposures have recently becomes a concern at smaller facilities. Five cases of PCP poisoning, including two fatalities, occurred in two small wood preservative plants. All cases presented with fever, including severe hyperpyrexia in two; an increased anion gap and renal insufficiency were noted in two others. PCP may uncouple oxidative phosphorylation, resulting in a poisoning syndrome characterized by hyperpyrexia, diaphoresis, tachycardia, tachypnea, abdominal pain, nausea, and even death.

Adult↗
PubMed1976

Uric acid catabolism in the woolly monkey.

The degradation and excretion of 2-14C-uric acid were examined in three adult woolly monkeys (Lagothrix lagothrichia) to determine the basis for the relatively high serum and urinary uric acid concentrations previously reported in this species. Like man and the great apes which lack uricase, but in distinction to most other mammals, these animals converted very little urate to allantoin. Uric acid turnover, as has been reported for other New World monkeys, was several times that of normal man. Renal urate excretion as well as disposition by extrarenal mechanisms may protect Lagothrix vrom hyperuricemia. The capacity to convert urate to allantoin appears to have been lost late in the evolution of New World monkeys. The woolly monkey deserves further study as a primate model for investigations of enzyme replacement strategies.

Animals↗
PubMedDate not supplied

Reproduction and the workplace: an industry perspective.

The main issue confronting industry in addressing reproductive health and the workplace is how to obtain needed data. The advantages and limitations of four methods of data collection--literature reviews, toxicology, epidemiology, and medical surveillance--are described, and recommendations made for improving reproductive health monitoring by industry.

Animals↗