Toxic effects of orally ingested oil from the Deepwater Horizon spill on laughing gulls.

The explosion of the Deepwater Horizon oil rig released, millions of gallons of oil into the environment, subsequently exposing wildlife, including numerous bird species. To determine the effects of MC252 oil to species relevant to the Gulf of Mexico, studies were done examining multiple exposure scenarios and doses. In this study, laughing gulls (Leucophaeus atricilla, LAGU) were offered fish injected with MC252 oil at target doses of 5 or 10mL/kg bw per day. Dosing continued for 27 days. Of the adult, mixed-sex LAGUs used in the present study, ten of 20 oil exposed LAGUs survived to the end of the study; a total of 10 of the oil exposed LAGUs died or were euthanized within 20 days of initiation of the study. Endpoints associated with oxidative stress, hepatic total glutathione (tGSH), oxidized glutathione (GSSG) and reduced glutathione (rGSH) significantly increased as mean dose of oil increased, while the rGSH:GSSG ratio showed a non-significant negative trend with oil dose. A significant increase in 3-methyl histidine was found in oil exposed birds when compared to controls indicative of muscle wastage and may have been associated with the gross observation of diminished structural integrity in cardiac tissue. Consistent with previous oil dosing studies in birds, significant changes in liver, spleen, and kidney weight when normalized to body weight were observed. These studies indicate that mortality in response to oil dosing is relatively common and the mortality exhibited by the gulls is consistent with previous studies examining oil toxicity. Whether survival effects in the gull study were associated with weight loss, physiologic effects of oil toxicity, or a behavioral response that led the birds to reject the dosed fish is unknown.

Reprint of: Overview of avian toxicity studies for the Deepwater Horizon Natural Resource Damage Assessment.

The Oil Pollution Act of 1990 establishes liability for injuries to natural resources because of the release or threat of release of oil. Assessment of injury to natural resources resulting from an oil spill and development and implementation of a plan for the restoration, rehabilitation, replacement or acquisition of natural resources to compensate for those injuries is accomplished through the Natural Resource Damage Assessment (NRDA) process. The NRDA process began within a week of the Deepwater Horizon oil spill, which occurred on April 20, 2010. During the spill, more than 8500 dead and impaired birds representing at least 93 avian species were collected. In addition, there were more than 3500 birds observed to be visibly oiled. While information in the literature at the time helped to identify some of the effects of oil on birds, it was not sufficient to fully characterize the nature and extent of the injuries to the thousands of live oiled birds, or to quantify those injuries in terms of effects on bird viability. As a result, the US Fish and Wildlife Service proposed various assessment activities to inform NRDA injury determination and quantification analyses associated with the Deepwater Horizon oil spill, including avian toxicity studies. The goal of these studies was to evaluate the effects of oral exposure to 1-20ml of artificially weathered Mississippi Canyon 252 oil kg bw-1 day-1 from one to 28 days or one to five applications of oil to 20% of the bird's surface area. It was thought that these exposure levels would not result in immediate or short-term mortality but might result in physiological effects that ultimately could affect avian survival, reproduction and health. These studies included oral dosing studies, an external dosing study, metabolic and flight performance studies and field-based flight studies. Results of these studies indicated changes in hematologic endpoints including formation of Heinz bodies and changes in cell counts. There were also effects on multiple organ systems, cardiac function and oxidative status. External oiling affected flight patterns and time spent during flight tasks indicating that migration may be affected by short-term repeated exposure to oil. Feather damage also resulted in increased heat loss and energetic demands. The papers in this special issue indicate that the combined effects of oil toxicity and feather effects in avian species, even in the case of relatively light oiling, can significantly affect the overall health of birds.

Overview of avian toxicity studies for the Deepwater Horizon Natural Resource Damage Assessment.

The Oil Pollution Act of 1990 establishes liability for injuries to natural resources because of the release or threat of release of oil. Assessment of injury to natural resources resulting from an oil spill and development and implementation of a plan for the restoration, rehabilitation, replacement or acquisition of natural resources to compensate for those injuries is accomplished through the Natural Resource Damage Assessment (NRDA) process. The NRDA process began within a week of the Deepwater Horizon oil spill, which occurred on April 20, 2010. During the spill, more than 8500 dead and impaired birds representing at least 93 avian species were collected. In addition, there were more than 3500 birds observed to be visibly oiled. While information in the literature at the time helped to identify some of the effects of oil on birds, it was not sufficient to fully characterize the nature and extent of the injuries to the thousands of live oiled birds, or to quantify those injuries in terms of effects on bird viability. As a result, the US Fish and Wildlife Service proposed various assessment activities to inform NRDA injury determination and quantification analyses associated with the Deepwater Horizon oil spill, including avian toxicity studies. The goal of these studies was to evaluate the effects of oral exposure to 1-20ml of artificially weathered Mississippi Canyon 252 oil kg bw-1 day-1 from one to 28 days or one to five applications of oil to 20% of the bird's surface area. It was thought that these exposure levels would not result in immediate or short-term mortality but might result in physiological effects that ultimately could affect avian survival, reproduction and health. These studies included oral dosing studies, an external dosing study, metabolic and flight performance studies and field-based flight studies. Results of these studies indicated changes in hematologic endpoints including formation of Heinz bodies and changes in cell counts. There were also effects on multiple organ systems, cardiac function and oxidative status. External oiling affected flight patterns and time spent during flight tasks indicating that migration may be affected by short-term repeated exposure to oil. Feather damage also resulted in increased heat loss and energetic demands. The papers in this special issue indicate that the combined effects of oil toxicity and feather effects in avian species, even in the case of relatively light oiling, can significantly affect the overall health of birds.

Determination of cadmium in sewage sludge by differential pulse anodic stripping voltammetry.

A procedure was developed for the determination of cadmium in sewage sludge by differential pulse anodic stripping voltammetry. A sodium peroxide fusion carried out in zirconium crucibles was found to give satisfactory results, based on analysis of standard reference materials. Samples collected from the municipal sludge lagoon in Fort Wayne, Indiana were found to have cadmium abundances ranging from 120 to 250 ppm, with most samples falling in the 120 to 170 ppm range. Interference from zinc is easily eliminated by carrying out the deposition step at -0.95 V vs. Ag/AgCl. Lead-to-cadmium ratios as high as 50:1 (ppm basis) have no effect on the height of the cadmium peak.

GC/MS analysis of prostaglandins in ventricular cerebrospinal fluid from head injured humans.

The purpose of this study was to determine the levels of prostaglandins in ventricular cerebrospinal fluid (CSF) from severely head injured humans on successive days following injury. Sixteen samples from three patients were purified using XAD-2 and high pressure liquid chromatography and PGE2, PGF2alpha, and 6-keto-PGF1alpha were quantitated utilizing deuterated internal standards and gas chromatography-mass spectrometry. Generally, the levels of PGs in ventricular CSF were found to be higher than has previously been reported for PGs in CSF from spinal taps. PG levels ranged from reported for PGs in CSF from spinal taps. PG levels ranged from nondetectable to 11.8, 3.3 and 27.3 ng per ml for PGE2, PGF2alpha, and 6-keto-PGF2alpha, respectively. However, in one sample, PG levels were much higher than this range and approached the levels found in human cortical tissue. Analysis of red and white blood cell numbers in the CSF showed no relationship between cell numbers and prostaglandin levels. This study confirms a previous report that 6-keto-PGF2alpha is the major prostaglandin in CSF and demonstrates that PG levels in ventricular CSF from head traumatized humans can be greatly elevated.

Prostaglandin levels in isolated brain microvessels and in normal and norepinephrine-stimulated cat brain homogenates.

The levels of PGD2, PGE2, PGF2 alpha and 6-keto-PGF1 alpha (6KF1 alpha) produced from endogenous arachidonic acid (AA) were quantitated in cat cerebral cortical homogenates and microvessels isolated from cat cerebral cortex using gas chromatography/mass spectrometry (GC/MS). There was a six-fold enrichment of 6KF1 alpha levels in isolated microvessels, compared to homogenates, suggesting that 6KF1 alpha is of vascular, rather than neuronal origin. In order to further understand any possible role that norepinephrine (NE) might have on modulation of PG synthesis, we studied the effects of 0.5 mM NE on PG synthesis from endogenous AA and from 3H-PGG2, the endoperoxide precursor of PGs. In cat cortical homogenates NE induced a 74% increase in PGD2 and PGF2 alpha, a 62% increase in PGE2, and a 36% increase in 6KF1 alpha, as measured by GC/MS. NE caused a twofold increase in the conversion of 3H-PGG2 to 3H-PGF2 alpha, with a concomitant decrease in 3H-PGE2 and 3H-6KF1 alpha formation, and no change in 3H-PGD2 synthesis. NE had no effect on the total conversion of 3H-PGG2 to 3H-PGs, nor on the breakdown of 3H-PGG2 in the absence of brain tissue. We conclude that NE stimulates extravascular synthesis of PGD2, PGE2 and PGF2 alpha by stimulation of the prostaglandin synthetase complex, in addition to NE's stimulatory effect on the conversion of PGG2 to PGF2 alpha, and that the lack of effect on NE on 6KF1 alpha synthesis reflects either a failure to achieve an adequate concentration at the vascular tissue, or an absence of the mechanism whereby NE stimulates PG synthetase.

Effect of oral aspirin dose on platelet aggregation and vascular prostacyclin (PGI2) synthesis in humans and rabbits.

Large doses of oral aspirin inhibit platelet aggregation and vascular synthesis of the antiaggregatory vasodilator prostaglandin I2 (PGI2) by irreversibly acetylating the cyclooxygenase enzyme. In order to determine if one can achieve selective inactivation of platelet cyclooxygenase using oral doses of aspirin, we studied human and rabbit platelet aggregation and rabbit aortic synthesis of PGI2 before and 3 hr after various doses of aspirin. In rabbits, lower doses of aspirin produced a major inhibition of platelet aggregation and a minor inhibition of PGI2 synthesis, while higher doses of aspirin inhibited both platelet aggregation and vascular PGI2 synthesis. In humans, we found that a dose equivalent to approximately 1/4 of one 300 mg aspirin tablet consistently produced a major inhibition of cyclooxygenase-dependent platelet aggregation in a pattern similar to the inhibition of rabbit platelet aggregation where the majority of rabbit PGI2 synthetic capacity was not inhibited. In another rabbit study, we found that it takes the vasculature over 24 hr to return to control PGI2 synthetic capacity following a single, high dose of oral aspirin. In conclusion, we speculate that approximately 1/4 of an aspirin tablet, which inhibits a major portion of cyclooxygenase-dependent human platelet aggregation, may not inhibit a major portion of vascular cyclooxygenase-dependent PGI2 synthesis and may be more efficacious as an antithrombotic agent in man than are higher doses of aspirin.

Metabolism of prostaglandin D2 in the monkey.

[3H7]Prostaglandin D2 was biosynthesized and infused into an unanesthetized monkey. The urinary metabolites were isolated and subsequently identified by gas chromatography-mass spectrometry. Two pathways of prostaglandin D2 metabolism were identified and resulted in metabolites with prostaglandin D (3-hydroxycyclopentanone) and prostaglandin F (cyclopentane-1,3-diol) ring structures. The major prostaglandin D ring metabolite was identified as 9,20-dihydroxy-11,15-dioxo-2,3-dinorprost-5-en-1-oic acid. Nine other prostaglandin D ring metabolites were identified reflecting various combinations of metabolism by beta and omega oxidation, 15 dehydrogenation, and 13-14 reduction. In greater abundance were those prostaglandin D2 metabolites which had the prostaglandin F ring structure. The major prostaglandin D2 metabolite which had the prostaglandin F ring structure was identified as 9,11,15-trihydroxy-2,3-dinorprosta-5,13-dien-1-oic acid (dinor prostaglandin F2 alpha). Nine other metabolites with the prostaglandin F ring structure were identified, including prostaglandin F2 alpha itself. These, for the most part, were the structural counterparts of the metabolites with the prostaglandin D ring. Since many prostaglandin D2 metabolites were found to be identical with the metabolites of prostaglandin F2 alpha, quantitative determinations of prostaglandin F ring metabolites may not be a specific indicator of prostaglandin F2 alpha biosynthesis. Likewise, data involving the measurement of a biological effect of prostaglandin D2 must be re-examined to account for the possible contribution of prostaglandin F2 alpha, a metabolite of prostaglandin D2, to the biological response.