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D Paschal

Publications and source records attributed to D Paschal.

9 recordsLinked to original sources
PubMed1998

Profiles of Great Lakes critical pollutants: a sentinel analysis of human blood and urine. The Great Lakes Consortium.

To determine the contaminants that should be studied further in the subsequent population-based study, a profile of Great Lakes (GL) sport fish contaminant residues were studied in human blood and urine specimens from 32 sport fish consumers from three Great Lakes: Lake Michigan (n = 10), Lake Huron (n = 11), and Lake Erie (n = 11). Serum was analyzed for 8 polychlorinated dioxin congeners, 10 polychlorinated furan congeners, 4 coplanar and 32 other polychlorinated biphenyl (PCB) congeners, and 11 persistent chlorinated pesticides. Whole blood was analyzed for mercury and lead. Urine samples were analyzed for 10 nonpersistent pesticides (or their metabolites) and 5 metals. One individual was excluded from statistical analysis because of an unusual exposure to selected analytes. Overall, the sample (n = 31) consumed, on average, 49 GL sport fish meals per year for a mean of 33 years. On average, the general population in the GL basin consume 6 meals of GL sport fish per year. The mean tissue levels of most persistent, bioaccumulative compounds also found in GL sport fish ranged from less than a twofold increase to that of PCB 126, which was eight times the selected background levels found in the general population. The overall mean total toxic equivalent for dioxins, furans, and coplanar PCBs were greater than selected background levels in the general population (dioxins, 1.8 times; furans, 2.4 times; and coplanar PCBs, 9.6 times). The nonpersistent pesticides and most metals were not identified in unusual concentrations. A contaminant pattern among lake subgroups was evident. Lake Erie sport fish consumers had consistently lower contaminant concentrations than consumers of sport fish from Lake Michigan and Huron. These interlake differences are consistent with contaminant patterns seen in sport fish tissue from the respective lakes; GL sport fish consumption was the most likely explanation for observed contaminant levels among this sample. Frequent consumers of sport fish proved to be effective sentinels for identifying sport fish contaminants of concern. In the larger study to follow, serum samples will be tested for PCBs (congener specific and coplanar), DDE, dioxin, and furans.

Animals↗
PubMed1997

Lead Exposure among Adult Temporary Residents in Eastern Europe: Should Blood Lead Levels Be Monitored?

Background: The risk of lead exposure among temporary residents in Eastern Europe is unknown. We monitored blood lead levels (BLLs) of Peace Corps Volunteers serving in Albania, Bulgaria, the Czech Republic, Hungary, Poland, Romania, and Slovakia from June 1991 through June 1994. Methods: BLLs were analyzed before the Volunteers left the United States (Sample 1), at mid-service (median of 15 months in-country, Sample 2), and at end-of-service (median of 22 months in-country, Sample 3). Results: Among 425 study participants who provided at least one follow-up blood sample, BLLs were significantly higher at Samples 2 and 3 compared to the U.S. baseline (paired t-test, p<.0001); however, the mean increase in BLL was only 1.0 ug/dL (range = -9.6 to 10.7). Overall, 74% of Volunteers experienced an increase in BLLs, 24% a decrease in BLLs, and 2% no change in BLLs at Sample 3 compared to their U.S. baseline. The highest increases in BLLs were among Volunteers in Albania, Bulgaria, and Romania (analysis of variance, p<.0001). In addition, men had higher mean increases in BLLs at Samples 2 and 3 compared to women (t-test, p=.017 and.029). Conclusions: The risk of significant lead exposure among our study population was low, and monitoring of BLLs among adult short-term residents in Eastern Europe does not seem to be indicated.

Journal Article↗
PubMed1982

Swift increase in alcohol metabolism (SIAM) in the mouse: comparison of the effect of short-term ethanol treatment on ethanol elimination in four inbred strains.

Ethanol metabolism increases 2 to 3 hr after the administration of ethanol. This phenomenon, called the swift increase in alcohol metabolism, has been compared in four inbred strains of mice (DBA/2J, C3H/HeJ, AKR/J and C57BL/6J). Basal rates of ethanol elimination were determined in individual mice after an i.p. injection of ethanol (2 g/kg). Little variability in this basal rate of ethanol elimination was observed within each strain. Mice were then exposed to ethanol vapor (20--22 mg/l) and rates of ethanol elimination were determined every 2 hr for 8 hr. By 2 to 3 hr, the rates of ethanol elimination initially increased 2- to 3-fold and then declined toward basal rates over the 8-hr interval in all strains studied. In another experiment, the dose of ethanol was varied to produce blood ethanol levels ranging from 50 to 250 mg/100 ml in both basal- and ethanol vapor-treated mice. Ethanol elimination increased greater than 1.5-fold in all four strains studied when basal rates were compared to rates observed after 4 hr of vapor treatment at the same blood ethanol level; however, the dose at which the maximal increase occurred differed among the strains. DBA/2J mice exhibited a maximal increase in the rate of ethanol elimination when ethanol concentrations were in the range of 30 to 50 mg/100 ml; the increase was smaller as the dose was increased. In contrast, AKR/J and C57BL/6J mice required 100 to 150 mg/100 ml of ethanol to activate the swift increase in alcohol metabolism effect. These data indicate clearly that the swift increase in alcohol metabolism effect is a common phenomenon and that dose and time relations differ in various inbred strains of mice.

Animals↗
PubMed1979

Determination of paraquat in marijuana by reversed-phase paired-ion high performance liquid chromatography.

A sensitive and selective method is described for the quantitative determination of paraquat in marijuana. Paraquat is extracted from finely ground plant material with hydrochloric acid with sonification, and the resulting acidic solution is extracted with chloroform:isopropanol (9:1) and evaporated to dryness. The residue is reconstituted with aqueous phosphate buffer pH 7.0; the solution is passed through a C-18 SEP-PAK TM and is analyzed with high performance liquid chromatography, using a reversed-phase column and an "ion pairing" reagent in the mobile phase. The recovery of paraquat in laboratory-spiked material varied from 90-97%. Results obtained with confiscated, field-sprayed marijuana by the procedure described were in excellent agreement with those obtained with a well-established ultraviolet procedure. The calculated limit of detection with this method is 2 ng of paraquat.

Cannabis↗
PubMed1978

Determination of atrazine in runoff water by high performance liquid chromatography.

A procedure is described for the determination of atrazine in runoff water from agricultural areas. Extraction and preconcentration are accomplished with a column of macroreticular resin. Separation and quantification are performed with high performance liquid chromatography with a microparticle reverse phase column. No interference is observed from either organics already present in the runoff water or from some 34 selected organic compounds. Excellent linearity is obtained for concentrations of atrazine from 0--120 PPB. Relative standard deviations of the overall procedure are 1--5%.

Atrazine↗