Carbon in Natural, Cultivated, and Restored Depressional Wetlands in the Mid-Atlantic Coastal Plain.

Aerial extent of wetland ecosystems has decreased dramatically since precolonial times due to the conversion of these areas for human use. Wetlands provide various ecosystem services, and conservation efforts are being made to restore wetlands and their functions, including soil carbon storage. This Mid-Atlantic Regional USDA Wetland Conservation Effects Assessment Project study was conducted to evaluate the effects and effectiveness of wetland conservation practices along the Mid-Atlantic Coastal Plain. This study examined 48 wetland sites in Delaware, Maryland, Virginia, and North Carolina under natural, prior converted cropland, and 5- to 10-yr post wetland restoration states. The North Carolina sites mainly contained soils dominated by organic soil materials and therefore were analyzed separately from the rest of the sites, which primarily contained mineral soils. Soil samples were collected using the bulk density core method by horizon to a depth of 1 m and were analyzed for percent carbon. The natural wetlands were found to have significantly greater carbon stocks (21.5 ± 5.2 kg C m) than prior converted croplands (7.95 ± 1.93 kg C m; < 0.01) and restored wetlands (4.82 ± 1.13 kg C m; < 0.001). The restored and prior converted sites did not differ significantly, possibly the result of the methods used to restore the wetlands, and the relatively young age of the restored sites. Wetlands were either restored by plugging drainage structures, with minimal surface disturbance, or by scraping the surface (i.e., excavation) to increase hydroperiod. Sites restored with the scraping technique had significantly lower carbon stocks (2.70 ± 0.38 kg C m) than those restored by passive techniques (6.06 ± 1.50 kg C m; = 0.09). Therefore, techniques that involve excavation and scraping to restore hydrology appear to negatively affect C storage.

Specific radioimmunoassay of amitriptyline and nortriptyline.

1 Antisera to nortriptyline were prepared by immunizing rabbits with N-succinylnortriptyline--bovine serum albumin conjugate. 2 A sensitive radioimmunoassay has been developed for the tricyclic antidepressants amitriptyline and nortriptyline. 3 amitriptyline and nortriptyline are separated from each other and from interfering metabolites before assay. 4 Using [3H]-imipramine and [3H]-succinylnortriptyline as tracers the radioimmunoassay can measure amitriptyline and nortriptyline levels down to 2--3 ng/ml using 0.05 ml plasma sample. 5 Agreement between the radioimmunoassay and a gas-chromatographic assay was excellent for both amitriptyline and nortriptyline.

Galactose tolerance studies of individuals with reduced galactose pathway activity.

The galactose tolerance of individuals with mutant genotypes affecting the activities of galactokinase (GALK) and galactose-1-phosphate uridylyltransferase (GALT) was examined. Genotypes studied were heterozygotes for the GALK and GALT forms of galactosemia, the Duarte-variant GALT, and Philadelphia-variant GALK alleles. The measurements used were urinary concentration of galactose during pregnancy in adults and in infants from the newborn period through the first 5 months of life; the rate of elimination of an intravenous infusion of galactose; and slit-lamp examination of the lens for evidence of cataracts. No unusual urinary excretions of galactose were noted in any of the age groups studied. Intravenous galactose tolerance tests were normal in all but two women, a mother and daughter heterozygous for the GALK-deficient form of galactosemia (GALKG/GALKA). Six other GALKG/GALKA subjects had normal tolerance studies. The intrafamilial consistency and interfamilial differences in the galactose tolerance of GALKG/GALKA individuals suggest heterogeneity of the genes responsible for the GALK-deficient form of galactosemia. Although subclinical cataracts were observed in several individuals, their significance relative to the mutant genotype cannot be resolved with the available data.