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Biomedical subjects

H L Johnson

Publications and source records attributed to H L Johnson.

90 records · Page 5Linked to original sources
PubMedDate not supplied

Correlation of calculated electronic parameters of fifteen aniline derivatives with their mutagenic potencies.

Electronic parameters for a series of amino-, chloro-, and nitro-substituted anilines relative to their potential for activation to hydroxylamines, aryl-nitrenium ions, and ring epoxides, and to their potential deactivation to phenols were calculated using semi-empirical molecular orbital methods. The relative mutagenic activities of aminoanilines could be explained by parameters reflecting potential for N-hydroxylation and stability of the arylnitrenium ions. Both chloro and nitro groups deactivate the amine group to N-hydroxylation and the ring to epoxidation, and no active products from cytochrome P-450 would be predicted. This result is consistent with lack of mutagenic activity observed for chloro derivatives, but does not account for activity of the nitro derivatives, which is presumed to be due to transformation of the nitro group itself to an active mutagenic species by other enzyme systems.

Aniline Compounds↗
PubMedDate not supplied

Intrauterine cocaine and crack exposure: neonatal outcome.

OBJECTIVE: Adverse health effects are associated with intrauterine cocaine exposure. The purpose of this study was to investigate the impact of fetal cocaine and crack exposure on neonatal outcome. STUDY DESIGN: We enrolled 386 mother-infant pairs, including 130 matched control pairs, in the study. The course of pregnancy and delivery was followed and neonatal outcome was assessed by physical and neurologic examination, as well as by the Brazelton Neonatal Behavioral Assessment Scale and the Neonatal Stress Scale. RESULTS: The cocaine-exposed neonates had significantly more adverse effects than the matched control infants. Birth weight, length, and head circumference were significantly lower in the cocaine- and crack-exposed infants (p < or = 0.001). There were significantly more premature infants (p < or = 0.007) in this group. They demonstrated significant abnormalities on the neurologic examination (p < or = 0.001), inferior performance on the Brazelton Neonatal Behavioral Assessment Scale (p < or = 0.001), and higher scores on the Neonatal Stress Scale (p < or = 0.001). Predictors of negative neonatal outcome were maternal age (p < or = 0.02), poor paternal relationship with the mother (p < or = 0.002), crack use (p < or = 0.004), cocaine use (p < or = 0.009), and marijuana use (p < or = 0.05). CONCLUSION: The single most important predictor of neonatal outcome is the frequency, quantity, and type of cocaine used.

Adult↗