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Biomedical subjects

H Rhoades

Publications and source records attributed to H Rhoades.

At least 19 recordsLinked to original sources
PubMed2001

Dextroamphetamine for cocaine-dependence treatment: a double-blind randomized clinical trial.

A properly implemented agonist treatment regimen should improve retention and reduce illicit drug use. Cocaine-dependent subjects (N = 128) were enrolled in a 12-week randomized, double-blind, placebo-controlled trial. In the multistage dosing design, subjects initially received placebo (PBO) or 15 to 30 mg of dextroamphetamine sulfate, sustained-release capsules. At week 5, the dose doubled to 30 mg or 60 mg for active groups. Subjects attended the clinic twice a week, provided urine samples, obtained medication, and had one behavioral therapy session a week. Retention was best for the 15- to 30-mg group, whereas the proportion of benzoylecgonine-positive urine screens was, from lowest to highest, 30 to 60 mg, 15 to 30 mg, and PBO at study end. Dosing must be refined. The results provide support for additional examination of the agonist model in psychostimulant-dependence treatment.

Adult↗
PubMed2000

Risperidone for the treatment of cocaine dependence: randomized, double-blind trial.

A partial blockade of the multiple actions of cocaine is one strategy by which cocaine dependence may be treated. Risperidone, a 5-hydroxytryptamine and dopamine D2 antagonist, is an atypical antipsychotic and was a candidate medication for the treatment of cocaine dependence. One hundred ninety-three cocaine-dependent subjects were enrolled in a 12-week, randomized, double-blind, placebo-controlled trial. Subjects initially received either placebo or 4 or 8 mg of risperidone, with a subsequent change to active doses of 2 mg and 4 mg. Subjects attended the clinic twice each week, provided urine samples, obtained medication, and underwent one behavioral therapy session per week. The study was terminated at the interim analysis. Retention was worse for the 4- and 8-mg active medication groups. Side effects were primarily associated with the 8-mg dose, although neither 2 mg nor 4 mg was well accepted by subjects. There was no reduction in cocaine use associated with risperidone. The results suggest that although antagonists might be a useful treatment approach, such as in the treatment of opiate dependence, risperidone is unlikely to find broad acceptance with the treatment-seeking population.

Adult↗
PubMed1999

Use of monetary reinforcers by cocaine-dependent outpatients.

Monetary reinforcers have not been widely used as contingent reinforcers in the treatment of drug abuse, despite their demonstrated effectiveness. This is primarily due to concern that drug abusers will use monetary reinforcers to procure drugs. The present study addressed this concern by examining 48 cocaine-dependent outpatients' biweekly self-reports of how they used their earned reinforcers. For each subject, their reinforcement usage was classified into 12 higher-order categories and 34 subcategories. Usage proportions were calculated for each. Results indicated that monetary reinforcers were used very infrequently to acquire drugs or alcohol (2%). Reinforcers were used primarily for daily life activities (25%) (e.g., food and gas), money-related uses (18%) (e.g., savings and repaying debts), personal use (15%) (e.g., cosmetics and clothes), and household items (11%) (e.g., rent and bills). These findings challenge the concern that drug abusers use monetary reinforcers to purchase drugs and have important implications for the use of contingent monetary reinforcers in treatment settings.

Adult↗
PubMed1997

Studies of violent and nonviolent male parolees: II. Laboratory and psychometric measurements of impulsivity.

Males parolees were recruited into a laboratory study to determine the relationship between their previous criminal history (violent versus nonviolent), and behavioral and psychometric measures of impulsivity. During sessions, subjects were given two response options defined as: 1) an impulsive choice--small monetary reward after a short fixed delay; and 2) a self-control choice--a larger monetary reward after a variable longer delay. Based upon an extensive experimental literature in animals and humans related to delay of gratification, the degree of impulsivity was defined as the proportion of trials on which the subject selected the impulsive option. Our results indicated that the violent subjects selected the impulsive option significantly more often than the nonviolent parolees. The number of impulsive responses parolees emitted was significantly correlated with the number of aggressive responses reported in an earlier paper. This study provides support for the relationship between impulsivity and aggression among male parolees.

Adult↗
PubMed1997

Desipramine versus phenelzine in recurrent unipolar depression: clinical characteristics and treatment response.

We compared desipramine with phenelzine in a double-blind, parallel-groups study of 43 outpatients with recurrent unipolar depression. Response to the two drugs was similar, with an overall average reduction in scores on the Hamilton Rating Scale for Depression of about 50% over 6 weeks. Improvement was negatively correlated with initial severity of depression, especially in patients treated with desipramine. Response to desipramine was better in patients with moderate to severe stressors and no previous hospitalizations. Response to either treatment was better in patients whose course consisted of recurrent depressions with a stable baseline, even if the baseline was dysthymic.

Adolescent↗
PubMed1997

Replacement medication for cocaine dependence: methylphenidate.

Agonists, or "replacement medications," are useful adjuncts in treatment of opiate and nicotine dependence. They have not been systematically examined in cocaine dependence. Results of early open trials with methylphenidate for treatment of cocaine dependence were equivocal. Twenty-four cocaine-dependent subjects were enrolled in an 11-week double-blind, placebo-controlled study of methylphenidate. Assignment was random. Intake included a 2-day human laboratory procedure in which subjects received initial doses of methylphenidate or placebo. Subjects attended the clinic Monday through Friday and received oral doses of methylphenidate (5 mg plus 20-mg sustained release) or placebo at 8:00 a.m., with afternoon and weekend take-home doses (20 mg sustained-release or placebo) provided in Medication Events Monitoring System bottles to monitor compliance. Clinic visits included therapy sessions, electrocardiograms, self-report measures, and twice-weekly urine screens. The two groups were equivalent in terms of retention (methylphenidate 48% and placebo 42%) and had similar cocaine use outcomes (40% benzoylecgonine-positive urine screens). There were no significant adverse effects. The doses were sufficient to permit detection of psychoactive effects ("stimulant," "more energy") and side effects ("jitteriness," "eating less") without increased "craving." Additional medications with different effects profiles are being studied to further evaluate the replacement model in cocaine dependence.

Adult↗
PubMed1995

Fluoxetine is ineffective for treatment of cocaine dependence or concurrent opiate and cocaine dependence: two placebo-controlled double-blind trials.

Cocaine dependence has proved difficult to treat, whether occurring alone or in combination with opiate dependence. No medication has been demonstrated to be uniquely effective. Fluoxetine was examined as a candidate in two randomized, double-blind, placebo-controlled trials, one with cocaine-dependent patients (study 1) and the other with patients both cocaine and opiate dependent (study 2). It was selected for known specific action, antidepressant effects, minimum side effects, and data showing reduced cocaine effect and self-administration. Clinic visit frequency requirement, a variable with implications for treatment and cost, was also examined in study 1. A total of 228 patients in study 1 and 21 patients in study 2 completed consent and intake procedures. Patients with serious medical or DSM-III-R diagnoses other than cocaine dependence (study 1) or opiate and cocaine dependence (study 2) were excluded. Study 1 patients were assigned to one of two visit frequency schedules (2 or 5 days/week) and one of three medication doses (0, 20, or 40 mg of fluoxetine/day). Study 2 patients received placebo or 20 mg of fluoxetine and 65 to 80 mg of methadone and attended the clinic 5 days/week. All patients participated in individual therapy sessions. Urine screens were conducted twice weekly. A fluoxetine dose response relationship emerged in study 1 for retention with groups from best to worst being placebo, 20 mg, and 40 mg. Dose effect order was the same for both visit conditions. Cocaine use persisted in all groups. The two visits/week condition was correlated with better retention than the five visits/week condition. A significant interaction emerged between intake urine and visit frequency; patients with benzoylecognine screens at intake used cocaine significantly less in the 5 days/week condition, while exhibiting no reduction in the 2 days/week condition. Patients cocaine positive at intake were better retained with infrequent visits. In study 2, a transient reduction in benzoylecognine-positive drug screens emerged for the fluoxetine group. These complementary studies demonstrate that fluoxetine is ineffective in reducing cocaine use or craving. Study 1 also points to setting conditions modulating treatment outcome.

Adult↗
PubMed1994

The effects of high and low doses of methadone on cigarette smoking.

The effect of methadone dose on the cigarette smoking of five methadone maintenance subjects was studied in a clinical setting. Following a two-week baseline period, daily doses of methadone were either increased (50-80 mg) or decreased (80-50 mg) every two weeks according to an A-B-A-B study design. Continuous self-monitoring was used to collect data on natural smoking behavior, and expired air carbon monoxide (CO) levels were measured at each clinic visit. The predicted methadone dose-related changes in smoking were found in three of the five subjects. Fine-grained analysis of self-monitoring records showed that the proportion of total daily smoking was highest within 4 h after taking methadone for three subjects. CO levels were not significantly associated with smoking rate. The results further support and extend previous reports that methadone may produce dose-related increases in smoking. No reactive effects of self-monitoring were observed, and compliance with this procedure was extremely high, supporting the usefulness of this method for assessing natural smoking behavior in this population.

Adult↗
PubMed1994

Early presentation of hemispheric intracerebral hemorrhage: prediction of outcome and guidelines for treatment allocation.

Criteria for selecting patients for possible surgery in the management of intracerebral hemorrhage (ICH) are needed to plan a prospective therapeutic evaluation of surgical intervention. This study specifically addressed patients seen in the emergency room within a few hours of the ictus, many of whom were still awake, to identify and subsequently exclude from surgical procedure those expected to recover completely and those expected to die regardless of treatment. We retrospectively studied 75 patients evaluated at a mean time of 3 hours and 37 minutes after hemispheric ICH to determine factors that would predict both good and poor outcomes at the time of discharge. Eighty percent of our patients presented within 6 hours of symptom onset. These patients were younger and had more severe lesions than did those presenting later, yet most were still awake (mean admission Glasgow Coma Scale [GCS] score = 11.0). Using multivariate regression, we created two models. The first model predicts independent outcome, ie, Rankin 0 to 2, of all patients with a GCS score greater than 9 on admission who do not undergo surgery. The significant factors in this model were hemorrhage diameter, intraventricular extension, and age. The second model predicts poor outcome, ie, Rankin 5 and death, of all patients. GCS score, hemorrhage volume, age, and gender were the important factors in this model. We conclude that ICH patients presenting early to the emergency room have more severe lesions radiologically, although their initial clinical status may not be different from those seen late. Our models should identify and thus exclude those with very good and very poor prognoses from future randomized surgical trials.

Adult↗
PubMed1993

Value of single-photon emission-computed tomography in acute stroke therapeutic trials.

BACKGROUND AND PURPOSE: New therapeutic interventions for acute ischemic stroke are aimed at improving cerebral blood flow in the first 3 to 6 hours after symptom onset. Single-photon emission-computed tomography (SPECT) performed in the setting of clinical therapeutic trials may give us a better understanding of the physiological response to new forms of treatment and could impact acute management decisions. METHODS: We prospectively studied 15 patients with hemispheric ischemic stroke with SPECT within 6 hours of symptom onset and again at 24 hours. The ischemic defect was assessed in a semiquantitative manner that used computer-generated regions of interest (SPECT graded scale). This measure was correlated with clinical presentation (National Institutes of Health [NIH] Stroke Scale), initial clinical course (change in NIH Stroke Scale), long-term outcome (Barthel Index at 3 months), and complications of cerebral hemorrhage and edema. RESULTS: The severity of the SPECT graded scale on the admission scan correlated with the severity of neurological deficit (admission NIH Stroke Scale) (P < .05) and was positively associated with poor long-term outcome as measured with the Barthel Index (P < .001) and the complications of cerebral hemorrhage and massive cerebral edema (P < .005). In fact, there was a threshold value for the SPECT graded scale above which all patients suffered poor long-term outcome and the complications of cerebral hemorrhage and edema. CONCLUSIONS: The measurement of an ischemic defect using SPECT is a valid assessment of hemispheric stroke severity in the hyperacute setting and may be useful for selecting or stratifying patients in clinical therapeutic trials.

Acute Disease↗
PubMed1990

Baclofen does not protect against cerebral ischemia in rats.

Presynaptic release of glutamate into the extracellular compartment and activation of receptor-operated calcium channels may contribute to ischemic neuronal damage. We evaluated the effect of baclofen, a selective inhibitor of presynaptic glutamate release, on mortality, working memory, and light microscopic hippocampal and cortical damage in the four-vessel occlusion model of cerebral ischemia using 64 male Wistar rats. Baclofen (10 mg/kg i.p.) given 1 hour before and 30-60 minutes after 20 minutes of global ischemia did not lessen mortality, prevent ischemic cellular damage, or significantly improve working memory compared with no treatment. We conclude that preischemic and postischemic administration of baclofen does not protect neurons from ischemic injury.

Animals↗
PubMed1989

Prediction of carotid stenosis progression by lipid and hematologic measurements.

We followed 19 men and 19 women with asymptomatic carotid stenosis up to 30 months to determine whether hematologic or lipid abnormalities could identify those individuals developing progressing carotid atherosclerosis (defined as an increase in mean percent stenosis greater than or equal to 19% or an increase in a single region of greater than or equal to 23%) on B-mode carotid ultrasonography performed at 2- to 6-month intervals. Our patients demonstrated increased beta-thromboglobulin, platelet factor 4, and fibrinogen compared with age-matched controls. Eight patients developed progression of carotid stenosis, and this group had higher baseline low-density lipoprotein (LDL) and fibrinogen than the 30 nonprogressing patients. Multiple regression analyses of age, sex, smoking, coronary artery disease, peripheral vascular disease, diabetes, hypertension, and baseline high-density lipoprotein (HDL), HDL2, HDL3, LDL, beta-thromboglobulin, platelet factor 4, and fibrinogen identified coronary artery disease and elevated LDL and fibrinogen as the only independent variables significantly associated with the progressing group. We conclude that, in patients with carotid atherosclerosis, a combination of coronary artery disease and elevated LDL and fibrinogen will predict with 88% accuracy whether the patient will have progressing carotid stenosis.

Aged↗
PubMed1988

Efficacy and mechanism of action of a calcium channel blocker after global cerebral ischemia in rats.

Dihydropyridine calcium channel blockers such as nicardipine are under evaluation for treating acute cerebral ischemia because they may increase cerebral blood flow by causing vasodilation and because they may be cytoprotective in part by limiting production of arachidonic acid metabolites. We demonstrated in a previous study that nicardipine improves postischemic neuronal function, as measured by somatosensory evoked potentials, without reducing the extent of light-microscopic CA-1 hippocampal histologic damage. To characterize further the effect of nicardipine on global ischemic injury, we administered the drug beginning 24 hours before 30 minutes of four-vessel ischemia in Wistar rats. We then measured hippocampal ATP, phosphocreatine, and glucose contents immediately and 2 hours after ischemia, and measured learning ability (working and reference errors) on an eight-arm radial maze beginning 30 days after ischemia. To gain insight into the possible mechanism of action, we measured production of arachidonic acid metabolites (eicosanoids: TXB2 and 6-keto-PGF1 alpha) and hemispheric and hippocampal cerebral blood flow by the [14C]butanol indicator fractionation technique immediately and 2 hours after ischemia. Nicardipine was associated with fewer working errors (p less than 0.02) but no difference in reference errors. The drug had no effect on energy metabolites, cerebral blood flow, or eicosanoids immediately after ischemia, but ATP, phosphocreatine, and cerebral blood flow all returned to normal levels significantly more rapidly during reperfusion in treated rats. Nicardipine improves behavioral, electrophysiologic, and mitochondrial function after ischemia without preventing cellular damage and improves postischemic reperfusion. The drug's positive effect appears to occur during reperfusion.

Adenosine Triphosphate↗
PubMedDate not supplied

Contingent reinforcement for reduced carbon monoxide levels in methadone maintenance patients.

Five cigarette smoking methadone maintenance patients (MMP) participated in a within-subjects (A-B-A-B) study involving repeated application of carbon monoxide (CO)-contingent payments for reductions in smoke intake. To replicate and extend findings from an earlier study in non-drug-abusing smokers (Stitzer & Bigelow, 1982), we used the same contingent reinforcement procedure that involved the delivery of a monetary payment ($5) for CO readings which were 50% or less than the average value of readings obtained during the prior noncontingency period. Although four of the five subjects earned the contingent payment on at least three of the eight occasions, the overall effect of the intervention on CO level was nonsignificant. Daily smoking records revealed significantly lower rates during the first contingency intervention for the group as a whole. Significant correlations between CO and the time interval since smoking prior to CO measurement were found. The rather modest intervention effects suggest that important parameters be considered when designing contingency management procedures to reduce cigarette smoking in this difficult population of drug abusers.

Breath Tests↗