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D Hickman

Publications and source records attributed to D Hickman.

27 records · Page 2Linked to original sources
PubMed1991

N-acetyltransferase polymorphism. Comparison of phenotype and genotype in humans.

N-Acetyltransferase (NAT) isoenzymes are encoded at two loci. One locus encodes an NAT which is expressed widely in tissues, does not vary amongst human individuals and is termed monomorphic NAT (mNAT). The second locus encodes an NAT which is termed polymorphic NAT (pNAT), has a distinct tissue distribution and is responsible for the difference in ability between individuals in acetylating certain arylamine (e.g. sulphamethazine) and hydrazine (e.g. isoniazid) drugs which are polymorphic substrates. We describe a simple DNA based method for genotyping individuals for pNAT. The 'fast' NAT allele (F1) and the three 'slow' alleles (S1, S2 and S3) can be distinguished by using PCR with oligonucleotide primers specific for pNAT followed by restriction enzyme digestion of the amplified product. Heterozygotes are easily identified. The genotype of individual Caucasians compares well with the extent of acetylation of sulphamethazine. The allele distribution of the Caucasian population described here differs from that reported after Southern blot analysis of a Japanese population (Deguchi et al., J Biol Chem 265: 12757-12760, 1990). The most frequent allele at the polymorphic nat locus in Caucasians, S1, is absent in the Japanese population. This difference between the two populations is likely to be the basis of the known interethnic variation in acetylator phenotype frequencies.

Acetylation↗
PubMed1989

The importance of acid digestion of urine prior to spontaneous deposition of 210Po.

Historically, radiochemical analysis of 210Po in urine has used spontaneous deposition of the nuclide directly from raw urine onto a suitable metal disc. Consequently, the urinary excretion fraction for Po in some current metabolic and dosimetric models is based on studies which inherently assume that metabolized (i.e., filtered out of the blood by the kidneys) 210Po is plated with the same efficiency as tracer 210Po which has been added to urine samples. Urine samples collected after intravenous administration of 210Po citrate to two species of nonhuman primates were divided and simultaneously analyzed via two methods: the historical procedure of plating 210Po from raw urine for one sample and a method which includes the addition of 208Po tracer and sample digestion with concentrated HNO3 prior to 210Po deposition for the other sample. A more significant amount of 210Po was consistently recovered when the urine was wet ashed then when it was not wet ashed. A temporal relationship was found to describe the change in the ratio of the deposition recoveries for the two methods. Possible mechanisms for this phenomenon and its dosimetric implications are discussed.

Animals↗
PubMed1987

Computerized versus standard administration of the Jenkins Activity Survey (Form T).

Using 60 male university students as subjects, this investigation compared the psychometric properties of computerized and paper-and-pencil versions of the student version (Form T) of the Jenkins Activity Survey. Data indicated that these different versions of the JAS demonstrated similar norms, reliabilities, and validities. The comparability of the JAS across administration modes suggested that computerizing the test does not significantly alter its characteristics. Implications of these findings and suggestions for future research are discussed.

Computers↗
PubMed1986

Comparative pathway analysis of radiocesium in the Hudson River Estuary: environmental measurements and regulatory dose assessment models.

This work summarizes the measurements and associated environmental dosimetry of reactor-released 137Cs and 134Cs and weapons-produced 137Cs in samples of water, shoreline sediment and fish collected from 1971 to 1980 in the Hudson River Estuary. Trends observed in annual mean concentrations and the resultant dose implications for man from each source are discussed. The human exposure pathways examined are: fish consumption, water consumption, swimming and recreational use of the shoreline. Based on environmental measurements, a maximum, adult, whole-body, 50-y committed effective dose equivalent (CEDE) of 0.79 mu Sv (79 mu rem) is estimated from fish consumption in 1971, the year of maximum reactor discharge of the radiocesiums. For comparison, during the period 1974-79, mean estimates (+/- 1 SD) of the CEDE based on environmental measurements and attributed to other pathways are as follows: consumption of indigenous fish species caught downstream of the reactor outfall, 0.05 +/- 0.02 mu Sv (5 +/- 2 mu rem); consumption of fresh water sampled upstream of the reactors, 0.02 +/- 0.03 mu Sv (2 +/- 3 mu rem); and swimming, 10(-4) +/- 10(-4) mu Sv (0.01 +/- 0.01 mu rem). In addition, external, whole-body exposure resulting from recreational use of the shoreline 1.6 km downstream of the reactors is estimated to be 1.2 X 10(-8) C kg-1 (46 +/- 11 mu R yr-1). The above dose estimates are based on consumption factors of 3.9 and 803 kg y-1 (fish and water, respectively) and on usage factors of 50 and 140 h y-1 (swimming and shoreline recreation, respectively). Differences in dose estimates obtained from these long-term environmental measurements and from assessment models currently recommended for use by the U.S. Nuclear Regulatory Commission (NRC) are discussed.

Adult↗
PubMed1982

Toxicity of hemorrhagic ascitic fluid associated with hemorrhagic pancreatitis.

Hemorrhagic pancreatitis was induced in dogs by a retrograde infusion of the pancreatic duct with a mixture of taurocholate sodium and trypsin. Seven of the 13 dogs were pretreated with antibiotics. The hemorrhagic ascitic fluid (HAF) recovered from the dogs' abdomens was injected intraperitoneally into mice in volumes of 2.5, 5, 10, 15, and 20 mL. The mice were divided into two groups depending on whether the HAF received was from dogs given antibiotics. The mortality among the mice was proportional to the volume of HAF injected. The mortality among mice receiving the sterile HAF was 79.4% at 20 mL, 55.8% at 15 mL, 29.4% at 10 mL, 26% at 5 mL, and 17% at 2.5 mL. There were no deaths among mice receiving 25 mL and saline solution and the mortality was 15% among mice receiving 20 mL of dog plasma.

Animals↗