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Biomedical subjects

M A Riddle

Publications and source records attributed to M A Riddle.

80 records · Page 5Linked to original sources
PubMed1986

Brief debrisoquin administration to assess central dopaminergic function in children.

Central dopaminergic (DA) function in children was assessed by monitoring plasma-free homovanillic acid (pHVA) levels after brief (18 hour) administration with debrisoquin sulfate, a peripherally active antihypertensive agent that blocks peripheral, but not central, HVA production. Brief debrisoquin administration resulted in marked reductions in pHVA in each of six patients studied. In five of the six patients, post-debrisoquin pHVA levels remained relatively stable over the six-hour period of observation. No significant cardiovascular or behavioral side effects of debrisoquin were observed. The brief debrisoquin administration method appears to be a safe, simple, and potentially valid peripheral technique for evaluating aspects of central dopaminergic function in children with neuropsychiatric disorders. Additional work is needed to further establish this method's validity and reliability.

Adolescent↗
PubMed1986

Rebound phenomena in Tourette's syndrome after abrupt withdrawal of clonidine. Behavioral, cardiovascular, and neurochemical effects.

Following an open trial of clonidine hydrochloride (3 to 8 micrograms/kg/day for 12 weeks), we studied the behavioral, cardiovascular, and neurochemical effects of abrupt clonidine withdrawal in seven patients with Tourette's syndrome aged 9 to 13 years. Five patients showed marked worsening of tics. After reinitiation of clonidine therapy, the time required for patients to return to prewithdrawal levels of tic symptoms ranged from two weeks to four months. Increases in motor restlessness, blood pressure, and pulse rate were also observed over the 72-hour period following abrupt withdrawal of clonidine. Plasma levels of free 3-methoxy-4-hydroxyphenylglycol, homovanillic acid, and urinary excretion of norepinephrine and epinephrine increased during the withdrawal period. Clonidine's effectiveness in Tourette's syndrome may be dependent on changes in dopaminergic as well as adrenergic mechanisms.

Adolescent↗
PubMed1986

Assessment of central dopaminergic function using plasma-free homovanillic acid after debrisoquin administration.

Central dopaminergic (DA) function in children and adults was assessed by monitoring plasma-free levels of the dopamine metabolite homovanillic acid (pHVA) before and after a single oral dose and chronic oral administration of debrisoquin. Debrisoquin inhibits peripheral metabolism of dopamine to HVA and does not cross the blood-brain barrier. By reducing peripheral formation of HVA through the use of debrisoquin, the remaining HVA in plasma more accurately reflects central DA activity. Debrisoquin administration resulted in marked reductions of pHVA in each of 12 patients studied. Eleven of the 12 subjects tolerated debrisoquin without physical or behavioral side effects. The debrisoquin administration method appears to be a safe and potentially valid technique for evaluating aspects of central dopaminergic function in children and adults.

Adolescent↗
PubMed1986

Cerebrospinal fluid monoamine precursor and metabolite levels in children treated for leukemia: age and sex effects and individual variability.

Lumbar cerebrospinal fluid (CSF) was obtained from children during and following treatment for acute lymphoblastic leukemia (ALL). One hundred ninety-two CSF samples from 50 subjects, which were selected to minimize the effects of the disease and its treatment (i.e., to approach "normality" as closely as possible), were analyzed for the monoamine precursors tyrosine (Tyr) and tryptophan (Trp) and the metabolites homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA). Levels of HVA (p less than 0.0001), 5-HIAA (p less than 0.002), and Tyr (p less than 0.05) decreased with age from 3 to 17 years. Significant correlations were observed between the acid metabolites HVA and 5-HIAA (r = 0.79) and between the amino acid precursors Tyr and Trp (r = 0.71). Within individuals, levels of all four compounds were relatively stable over time, with total mean coefficient of variation ranging from 20% to 25%. No significant sex differences for CSF levels of HVA, 5-HIAA, Tyr, or Trp were found. Assessment of CSF monoamine precursors and metabolites in children treated for ALL may provide a method for understanding the chronic effect of CNS trauma on the ontogeny of monoamine systems.

Adolescent↗
PubMedDate not supplied

MAOI treatment response: multiaxial assessment.

While studying the effectiveness of the MAOI isocarboxazid for the treatment of depression, we noted that many patients experienced a reduction of symptoms without equivalent improvement in other areas of their lives. We evaluated four outcome areas: symptoms, work, family functioning and social functioning. After 6 weeks on medication, symptoms improved the most, significantly more so than the other three areas. For the group of patients who completed 24 weeks on medication, all four outcome areas were further improved compared to the 6-week levels, with the improvement in work functioning reaching statistical significance. We conclude that the assessment of treatment outcome is more complex than the simple measurement of symptom reduction, and that different outcome areas are likely to improve at different rates and to different extents.

Adult↗
PubMedDate not supplied

Fluvoxamine open-label treatment of adolescent inpatients with obsessive-compulsive disorder or depression.

OBJECTIVE: Fluvoxamine, a monocyclic, specific serotonin uptake inhibitor with demonstrated efficacy in obsessive-compulsive disorder (OCD) and depression in adults, is marketed in more than 30 countries worldwide, including Israel. In the United States, where fluvoxamine is available only on an investigational basis, marketing appears imminent. This study evaluates the safety and efficacy of fluvoxamine in adolescents. METHOD: In an 8-week, open-label trial of fluvoxamine, 20 adolescent inpatients, ages 13 to 18 years, were treated for OCD (n = 14) or major depressive disorder (MDD)(n = 6) with daily doses ranging from 100 to 300 mg. Target symptoms were rated at regular intervals with the Yale-Brown Obsessive Compulsive Scale (Y-BOCS); Suicide Potential Scales (SPS); Beck Depression Inventory (BDI); the Overt Aggression Scale (OAS); and the Children's Global Adjustment Scale (CGAS). RESULTS: Fluvoxamine proved relatively safe and was especially effective in the patients with OCD; mean Y-BOCS scores decreased significantly (p < .0001) from 28.0 to 19.8 on medication. Although fluvoxamine also appeared effective in decreasing depression and bulimic symptoms, its impact on impulsive, suicidal, and anorectic symptoms was less clear. The commonest side effects (n > or = 3) were dermatitis, insomnia, hyperactivity, excitement, anxiety, tremor, and nausea. Fluvoxamine was discontinued in four patients because of side effects; the most serious side effect occurred in two debilitated anorexic patients, of whom one became delirious and the other developed hallucinations. CONCLUSION: Preliminary evidence suggests that short-term treatment of adolescents with fluvoxamine is relatively safe and may be effective for OCD and some affective spectrum symptoms.

Adolescent↗
PubMedDate not supplied

Psychiatrically hospitalized children: a critical review.

The high cost of inpatient hospitalization and the rise in the number of private psychiatric beds for children and adolescents prompt several questions about who is using these services. To examine these issues, a review focusing on the use of psychiatric inpatient services by children was undertaken. The history of inpatient care of children is briefly outlined, recent public policies contributing to the rise in the number of psychiatric beds are considered, and findings from available studies are reviewed. We conclude that the data base is inadequate to draw many conclusions about who is using child psychiatric inpatient services. There appear, however, to be important differences in use of inpatient services according to age and perhaps by institutional type and geographic region. Suggestions for future research and some of the social policy implications are discussed as well.

Adolescent↗