Double-blind methylphenidate trials: practical, useful, and highly endorsed by families.

OBJECTIVE: To evaluate a 3-week, randomized, double-blind, methylphenidate placebo-controlled trial (MPT) in routine practice for children with attention-deficit disorder. PATIENTS AND METHODS: School-aged children with attention-deficit/hyperactivity disorder (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria) who enrolled an "N of 1" trial at a pediatric tertiary care center were eligible. Families (n = 50) with a child eligible for the MPT were given 3 bottles of identical capsules. The capsules contained, in random order: placebo of the prescribed dose of methylphenidate (Ritalin) hydrochloride (0.3 mg/kg or 0.6 mg/kg). Families gave the child 1 capsule at 8 AM and 1 capsule at noon. The family, teacher, and physician were blinded for the order of medication. Conners questionnaires (Conners Parent Questionnaire and Conners Teacher Questionnaire) and written comments were completed by parents and teachers at baseline and at the end of each week. Once MPT results were known and following discussion with the physician, families decided whether to continue methylphenidate therapy. Families were interviewed by telephone 14 to 21 months after the MPT. RESULTS: Forty-three (86%) of the 50 eligible children (mean age, 129 months) were contacted. No family found the MPT difficult, but 6 trials were incomplete, usually because of side effects. All families used the MPT to decide if methylphenidate was the correct treatment choice for their child and 68% (34 of 50 families) used the results exclusively. The remaining 16 families believed the MPT was helpful. Overall, 31 (72%) of the 43 children had a good response to methylphenidate treatment--20 (47%) continued to use it for longer than 12 months and 8 (26%) for 2 to 12 months; 3 responders chose not to use it after the MPT. Nine of the 43 families chose not to use methylphenidate treatment; however, all indicated that participating in the MPT helped them to make that decision. In follow-up interviews, the same proportion of methylphenidate users and nonusers reported improvement in many areas of function including significantly less time spent doing homework. Users reported reduced aggression (P<.001) and fewer discipline problems (P<.01) compared with nonusers. CONCLUSIONS: An "N of 1" MPT was easily performed and permitted families to decide whether to use methylphenidate for long-term treatment of attention-deficit disorder or attention-deficit/hyperactivity disorder. Regardless of methylphenidate use or lack of use, the condition of all of these children was improved at follow-up.

The ethical arguments concerning the artificial ventilation of patients with motor neurone disease.

This paper focuses on the ethical dilemmas created by advanced technology that would allow patients with motor neurone disease to be sustained by artificial ventilation. The author attempts to support the patient's right to informed choice, arguing from the perspective of autonomy as a first order principle. The counter arguments of caregiver burden and financial restraints are analysed. In the UK, where active euthanasia is not legalized, the dilemma of commencing ventilation is seen to be outweighed by the problems of withdrawing this treatment. The lack of accurate data and protocols that would clarify the current situation is emphasized and the conclusion takes the form of a recommendation for further research.

Caffeine treatment and withdrawal in mice: relationships between dosage, concentrations, locomotor activity and A1 adenosine receptor binding.

Relationships between caffeine dose, methylxanthine tissue concentrations, adenosine receptor binding and locomotor activity were examined in CD-1 mice. A method of caffeine infusion via s.c. pumps provided constant steady-state methylxanthine concentrations. Mice receiving caffeine doses of 97 mg/kg/day (with mean plasma concentration of 2.7 micrograms/ml) demonstrated motor activity depression for 6 days after pump implantation (vs. vehicle-treated controls). Mice receiving caffeine doses of 194 mg/kg/day (mean plasma concentration of 7.1 micrograms/ml) demonstrated motor stimulation 4 and 24 hr after implantation. Mice receiving this dose for 6 days developed motor depression. A reduction in the stimulant effects of acute caffeine (20 mg/kg i.p.) was found in mice receiving caffeine infusions (194 mg/kg/day for 6 days) as compared to those receiving vehicle infusions, suggestive of drug tolerance. These dose- and time-dependent behavioral effects during caffeine-infusion were associated with decreases between 20 and 69% in specific binding of A1 adenosine radioligand 1,3-[3H]dipropyl-8-cyclopentylxanthine in vivo. Behavioral alterations during caffeine infusion appear to be mediated by A1 adenosine receptor occupancy. Increasing motor depression developed on days 1 and 2 after pump removal with values returning to control levels by days 4 and 6. Behavioral alterations were associated with in vivo binding increases of 98 and 324%, respectively, and a return to control values on days 4 and 6. In vivo binding alterations were not associated with ex vivo A1 receptor binding changes. Caffeine tolerance and withdrawal effects in this animal model appear to be mediated by chronic occupancy of A1 adenosine receptors. The behavioral and in vivo receptor binding alterations observed after caffeine discontinuation follow a time course similar to caffeine withdrawal in humans.

Caffeine-induced behavioral stimulation is dose-dependent and associated with A1 adenosine receptor occupancy.

Caffeine's psychomotor stimulant effects may relate to its blockade of central adenosine receptors. We examined acute caffeine effects on motor activity, adenosine receptor occupancy in vivo, and receptor affinity and density ex vivo. Acute doses of caffeine-sodium benzoate (0, 20, 40, and 60 mg/kg, intraperitoneally [0, 0.10, 0.21, 0.31 mu mol/kg]) were given to CD-1 mice and their activity was measured in an animal activity monitor over a 1-hour period. Adenosine receptor occupancy in vivo was quantified in mice 1 hour postdosage, using the high-affinity, A1 receptor selective adenosine antagonist [3H]-8-cyclopentyl-1,3-dipropylxanthine. Adenosine receptor binding affinities and densities were determined from analyses of binding studies in cortical, hippocampal, and brainstem membranes from treated mice (0 and 40 mg/kg caffeine). Caffeine doses of 20 and 40 mg/kg, corresponding to mean brain concentrations of 5 and 17 micrograms/g, increased all horizontal and vertical motor activity measures and stereotypy counts, as compared to doses of 0 and 60 mg/kg. Additionally, all acute caffeine doses significantly altered specific A1 binding in vivo (decreasing binding between 55% and 73% versus vehicle), presumably as it occupied A1 receptors. Therefore, at doses of 20 and 40 mg/kg, caffeine stimulated motor activity as it occupied A1 receptors; at a dose of 60 mg/kg (mean brain concentration of 26 micrograms/g) caffeine had no stimulant effect even though it appeared to occupy A1 receptors. Acute caffeine dosage did not alter ex vivo adenosine receptor binding affinity or density in any brain regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Learned taste aversion induced by cortical spreading depression.

Male albino rats were cannulated and placed on a 24 hr water deprivation schedule. The animals were allowed 10 min access to water in a large animal cage for 5 days. On the sixth day of deprivation the animals were randomly divided into 6 groups and given either 12 percent KCl, 25 percent KCl, or Ringers solution applied unilaterally or bilaterally to the cortex immediately after access to 8 percent sucrose. On the seventh day of deprivation, each rat was placed in a two-choice situation with the sucrose solution and water. Only the unilateral and bilateral 12 percent KCl groups developed an aversion to the sucrose. These results indicate that CSD has aversive as well as amnesic properties, there exists a gradient of amnesia, dependent on concentration, and that the cortex is not necessary for learning a taste aversion.