Extent and degree of shoreline oiling: Deepwater Horizon oil spill, Gulf of Mexico, USA.

The oil from the 2010 Deepwater Horizon spill in the Gulf of Mexico was documented by shoreline assessment teams as stranding on 1,773 km of shoreline. Beaches comprised 50.8%, marshes 44.9%, and other shoreline types 4.3% of the oiled shoreline. Shoreline cleanup activities were authorized on 660 km, or 73.3% of oiled beaches and up to 71 km, or 8.9% of oiled marshes and associated habitats. One year after the spill began, oil remained on 847 km; two years later, oil remained on 687 km, though at much lesser degrees of oiling. For example, shorelines characterized as heavily oiled went from a maximum of 360 km, to 22.4 km one year later, and to 6.4 km two years later. Shoreline cleanup has been conducted to meet habitat-specific cleanup endpoints and will continue until all oiled shoreline segments meet endpoints. The entire shoreline cleanup program has been managed under the Shoreline Cleanup Assessment Technique (SCAT) Program, which is a systematic, objective, and inclusive process to collect data on shoreline oiling conditions and support decision making on appropriate cleanup methods and endpoints. It was a particularly valuable and effective process during such a complex spill.

Differential densities of nitric oxide synthesizing nerves in the sphincteric and non-sphincteric smooth muscles of human gut during fetal development

Nitric oxide (NO) is involved in the inhibitory neurotransmission in the sphincter and non-sphincteric smooth muscles. However, the relative contribution of nitric oxid synthesizing innervation to these functionally diverse parts of the gut, particularly during development, is unknown. Gastrointestinal sphincters and adjoining non-sphincteric bowel segments were obtained by nicotinamide adenine deoxinucleotide ages between 12 and 23 weeks. NO synthesizing nerves were examined by nicotinamide adenine deoxinucleotide phosphate (NADPH) diaphorase histochemistry. The densities of NADPH positive nerves in the smooth muscle were quantified using a computerized image analyzing system on randon section. The NO synthesizing nerve density in intestinal smooth muscles decreased during fetal development as a results of increased interspacing between myenteric ganglia and a disproportionately larger increase in smooth muscle area than neuronal area. Similarly, the nerve densities were lower in sphincteric regions than adjoining non-sphincteric regions at the same gestational ages. There is a relative reduction of the density of NO synthesizing nerves in intestinal smooth muscle particularly in sphincteric regions during development. These findings may have relevance to the occurence of congenital dysmotility disordere of the sphincteric regions

Differential densities of nitric oxide synthesizing nerves in the sphincteric and non-sphincteric smooth muscles of human gut during fetal development

Nitric oxide (NO) is involved in the inhibitory neurotransmission in the sphincteric and non-sphincteric smooth muscles. However, the relative contribution of nitric oxide synthesizing innervation to these functionally diverse parts of the gut, particularly during development, is unknown. Gastrointestinal sphincters and adjoining non-sphincteric bowel segments were obtained from 14 human fetuses with gestational ages between 12 and 23 weeks. NO synthesizing nerves were examined by nicotinamide adenine deoxinucleotide phosphate (NADPH) diaphorase histochemistry. The densities of NADPH positive nerves in the smooth muscle were quantified using a computerized image analyzing system on random sections. The NO synthesizing nerve density in intestinal smooth muscles decreased during fetal development as a result of increased interspacing between myenteric ganglia and a disproportionately larger increase in smooth muscle area than neuronal area. Similarly, the nerve densities were lower in sphincteric regions than adjoining non-sphincteric regions at the same gestational ages. There is a relative reduction of the density of NO synthesizing nerves in intestinal smooth muscle particularly in sphincteric regions during development. These findings may have relevance to the occurrence of congenital dysmotility disorders of the sphincteric regions.