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Biomedical subjects

M Washburn

Publications and source records attributed to M Washburn.

29 records · Page 2Linked to original sources
PubMed1990

Examination of the relationships among drug use, emotional/psychological problems, and crime among youths entering a juvenile detention center.

Urine testing and confidential interviews of youths entering a juvenile detention center in a southeastern city produced some striking results in regard to their drug use, delinquent behavior, and emotional/psychological problems. Recent users of marijuana/hashish and cocaine had higher rates of referral to juvenile court for property and drug offenses than nonusers. The results suggest that interviewing and urine testing of youthful detainees for drug use at the point of entry into secure detention is a promising method for screening youngsters with histories of delinquent behavior. Implications of these findings are drawn.

Adolescent↗
PubMed1989

Physical abuse, sexual victimization, and illicit drug use: replication of a structural analysis among a new sample of high-risk youths.

Mounting evidence of serious adverse consequences of childhood physical and sexual abuse has important implications for public health officials and care providers. Given the potential impact on social policy of this area of inquiry, programmatic research is needed for the validation of theoretical models across populations and over time. This study, based on a sample of high-risk youths, replicates a structural model that specified the influence of child physical and sexual abuse on self-derogation and drug use. Results suggest that for male and female youths, physical abuse and sexual victimization had a direct effect on self-derogation and illicit drug use, and an indirect effect on drug use that was mediated by self-derogation. Moreover, structural coefficients for the model were found to be identical across gender. Subsequent analyses demonstrated the equivalence of the structural model of child physical and sexual abuse on drug use across two study cohorts. Implications for the identification and treatment of youths in high-risk groups are discussed.

Adolescent↗
PubMed1989

Electrophysiological correlates of presynaptic alpha 2-receptor-mediated inhibition of norepinephrine release at locus coeruleus synapses in dentate gyrus.

Despite an abundance of evidence that presynaptic alpha 2-adrenergic receptors mediate inhibitory control of the release of norepinephrine (NE) from the terminals of locus coeruleus (LC) neurons, few studies have demonstrated the physiological significance of this "autoreceptor"-mediated inhibition on NE-mediated synaptic activity within the mammalian brain. This question was addressed by examining the effects of systemic administration of alpha 2-adrenergic agonists and antagonists on the ability of LC stimulation to augment the population spike recorded in the dentate gyrus in response to activation of the perforant path (PP). Extracellular field potentials were recorded in the cell body and dendritic layer of dentate gyrus following single shocks of the entorhinal cortex in halothane-anesthetized rats. Stimulation of the ipsilateral LC 35 msec prior to PP activation produced a short-term enhancement of the population spike amplitude recorded in the cell layer but did not significantly alter dendritic potentials. The effects of LC stimulation were blocked by administration of the beta-adrenergic antagonist propranolol but not the alpha 2-antagonist idazoxan and were abolished by pretreatment of animals with the catecholamine neurotoxin 6-hydroxydopamine. Administration of clonidine reversibly abolished the enhancement produced by LC conditioning. The effect of clonidine was dose dependent and was blocked by administration of idazoxan, which restored the LC potentiative effect. Conditioning stimulation of LC noradrenergic axons in the dorsal bundle also potentiated the PP-evoked population spike, and this effect was equally sensitive to the depressant action of clonidine. In comparison, clonidine, in the range of dosages tested, did not significantly affect the potentials evoked in the dendritic or cell layer by presentations of unconditioned PP test stimuli. We interpret these data to provide evidence for a functional impairment of LC-mediated physiological action on postsynaptic target cells as a result of presynaptic alpha 2-autoreceptor-mediated feedback inhibition of NE release.

Action Potentials↗
PubMed1988

The relationship between physical and sexual abuse and tobacco, alcohol, and illicit drug use among youths in a juvenile detention center.

The relationships between child physical and sexual abuse and tobacco, alcohol, and illicit drug use are little understood and underinvestigated. Data gathered from a study of youths in a regional detention center permitted an examination of this issue. The results indicate that the youths' physical and sexual abuse experiences are significantly and positively related to their use of illicit drugs. The implications of these findings for further research are drawn.

Adolescent↗
PubMed1988

The relationship between physical and sexual abuse and illicit drug use: a replication among a new sample of youths entering a juvenile detention center.

The relationship between child physical and sexual abuse and illicit drug use are little understood and underinvestigated. Our previous study of this association found that a sample of detained youths' physical and sexual abuse experiences were related significantly and positively to their use of illicit drugs. Data gathered from a new sample of detained juveniles, interviewed 3 years after our first study, relating to this issue were examined and our previous findings were replicated.

Adolescent↗
PubMed1987

Physical abuse, sexual victimization and illicit drug use: a structural analysis among high risk adolescents.

The relationships between child physical and sexual abuse and illicit drug use are relatively unexplored and obscure. Data gathered from a sample of youths in a juvenile detention center permitted an examination of this important issue. A structural model, specifying the influence of child physical and sexual abuse variables on the youths' illicit drug use, directly and as mediated by self-derogation, was estimated among male and female detainees. Results suggest that for both gender groups, sexual victimization had a primarily direct effect on drug use, whereas physical abuse had both a direct and an indirect effect on drug use. The indirect effect of physical abuse on drug use was mediated by self-derogation. Further analysis indicated race did not affect the results. The implications of these results for theory and research on the etiology of drug use and the identification of youths in high risk groups who are likely to become seriously involved in drug use are discussed.

Adolescent↗
PubMedDate not supplied

Effects of pyrethroid insecticides on operant responding maintained by food.

The pyrethroids are potent insecticides with low concomitant mammalian lethality when compared with other major insecticides. While high doses can lead to hyperactivity, tremors, convulsion and death, low doses have not been as well studied. Since operant behavior can be a sensitive measure of CNS function, male Holtzman rats were trained on a VR25 schedule maintained by 45 mg food pellets. Rats were injected IP with one of four different technical grade pyrethroids: permethrin, allethrin, deltamethrin and fenvalerate. All agents were effective in reducing operant responding and did so in a dose-dependent manner at levels 10 to 100 times below their LD50 values. Time course studies indicated a relatively short duration of action for the Type I agents of less than 60 min for permethrin and 15 min for allethrin. Type II agents were generally effective for greater than 60 min. Results of these studies indicate that operant responding maintained by food is a sensitive measure of the behaviorally disruptive effects of subconvulsive doses of pyrethroids.

Allethrins↗