Evaluation of the expert system for respiratory therapy of newborns on archival data

The aim of this study was to evaluate the artificial ventilation expert system for neonates (AVES-N) using archival data. The recommendations of the system were compared to the decisions made by the expert-physician in the same clinical situation (patient condition, respirator settings). In our retrospective study we used data of 320 newborns which were ventilated in the Neonatal Intensive Care Unit of the Vanderbilt University Hospital in Nashville (USA). Best agreement between the recommendations of the system and the decisions of the experts was found for positive end expiratory pressure (PEEP), inspired oxygen fraction (FiO2) and peak inspiratory pressure (PIP)--about 70%. Worse agreement was found for time related parameters: respiratory frequency (f) - 54%, time of inspiration (ti) - 46%, time of next blood gas analysis - 15%. The expert system advised lower FiO2 PEEP and f. The differences were smaller in a group of patients who survived than in a group of patients who died. The overall agreement of the AVES-N advice and real therapeutic actions leads to the clinical evaluation of the expert system. The differences can be attributed to a) different therapeutic strategies at 2 NICU's, b) missing data regarding complications in the data base which were not taken into account by the expert system.

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.

Relapse prevention treatment for cocaine dependence: group vs. individual format

To investigate the role of treatment modality in relapse prevention treatment, 32 cocaine-dependent subjects were randomly assigned by cohorts to group-based relapse prevention (G-RP) or individually based RP (I-RP). The two RP formats were identical in content, consisting of 12 outpatient treatment sessions over a 2-month period immediately following hospitalization. The proportion of subjects providing cocaine-free urines at the end of RP treatment did not differ between formats; however, G-RP subjects reported using cocaine on significantly fewer days during treatment, and experiencing fewer cocaine-related problems than did I-RP subjects. Follow-up data collected at 12 and 24 weeks' posttreatment revealed no significant differences between RP formats on any cocaine-use outcome measures. Regardless of therapy format. RP treatment was related to statistically significant and sustained improvements in other areas of psychosocial functioning, including addiction severity, coping, and craving for cocaine. The overall findings suggest that the efficacy of relapse prevention training is not limited by therapy format.

Fluorogenic compound hydrolysis as a measure of toxicity-induced cytoplasmic viscosity and pH changes

If a fluorogenic compound, such as fluorescein diacetate, is added to a water solution containing living cells it becomes hydrolyzed by intracellular esterases into a fluorochrome whose fluorescence can be used to monitor the cytoplasmic pH and the cytoplasmic viscosity of the cells. In this paper we have used this technique to measure the effects of different concentrations of Co2+ and Cd2+ ions on the cytoplasmic pH and the cytoplasmic viscosity of a single cell culture. Our results indicate that the observed decrease in the efficiency of the intracellular hydrolyzation of fluorogenic substances in the presence of different concentrations of heavy metals could be caused by both a decrease in the cytoplasmic pH and an increase in the cytoplasmic viscosity. A decrease in cytoplasmic pH would decrease the effectiveness of the intracellular enzymes, whereas an increase in cytoplasmic viscosity would decrease diffusion which would also reduce the effectiveness of the reaction. The dependence of the reciprocal of the cytoplasmic viscosity on the concentration of these metals correlates well with published results on their toxicity.

A method for determination of the anisotropic properties of biomembranes

A methodology was developed for potential determination of the anisotropic properties of biomembranes. This method is based on the theoretical discretization of a continuous membrane used for finite element analysis and the simultaneous measurement of the displacement of nodes on the surface of a membrane. From the given loads and measured nodal displacements, one can assemble the resulting stiffness matrix and approximate the material properties associated with the membrane. Mathematical estimations and computer simulations were performed to determine the perturbation of load and displacement errors on the resulting material properties. The results indicated that the material properties are particularly sensitive to displacement errors. The displacement measurements may require an accuracy of 20 microns for a 4 x 4 cm2 specimen. Significant inaccuracies occur close to the points of load application.

Human methadone self-administration: effects of dose and ratio requirement

The effects of response requirement and small doses of methadone on human oral self-administration of methadone were examined. Three methadone maintenance patients stabilized at a dose of 80mg methadone per day were recruited as subjects. Completing a response requirement, fixed ratio (FR) of 32, 64 or 128 responses (FR32, FR64, FR128) on one button dispensed 10ml of drug solution. Completing the equivalent response requirement on a second concurrently available response button dispensed 10ml of vehicle. The opportunity to respond was unavailable until the drug or vehicle had been consumed. Each 10ml of drug solution contained methadone doses of 0.027, 0.054 or 0.108mg/ml. The frequency of deliveries was limited so that subjects could not ingest more than 54mg of methadone; the difference between the 80mg daily methadone dose and the methadone consumed in session was administered 30min post-session. At FR64 and FR128 the frequency of deliveries decreased, at the 0.054 and 0.027mg/ml doses, relative to the frequency of deliveries at FR32. The amount of methadone consumed increased with increases in methadone dose and decreased with increases in FR size. These results demonstrate the reinforcing effects of small unit doses of methadone. This procedure provides a sensitive baseline for examining effects of other pharmacological interventions on methadone ingestion in humans.

Orally delivered methadone as a reinforcer in rhesus monkeys

Methadone usually is taken orally for drug abuse treatment in humans but oral methadone self-administration by laboratory animals has not been investigated extensively. The present study examines acquisition and maintenance of oral methadone maintained responding in four adult male rhesus monkeys. Drug solution was available from one liquid delivery system and water from a second system during daily 3-h sessions. Locations of liquids were reversed each session, and liquid (0.65 ml per delivery) was delivered according to a fixed-ratio reinforcement schedule. Initially a test for the reinforcing effects of 0.00625-0.4 mg/ml methadone solutions was carried out but a consistent preference for drug over water was not seen. To establish methadone as a reinforcer, a fading procedure was used in which responding was first maintained by solutions of methadone (0.00625-0.4 mg/ml) combined with ethanol (0.0325-2.0% w/v). Subsequently, the concentration of the ethanol in the combination was gradually reduced to zero. Methadone-maintained responding (0.4 mg/ml) persisted when ethanol was no longer present. To confirm that the drug was serving as a reinforcer, the dose was varied: (a) by changing the volume delivered while the concentration was held constant and (b) by changing the concentration of the methadone while the volume per delivery was held constant. Over a wide range of doses, deliveries of methadone solution usually exceeded deliveries of concurrently available water. Orderly relationships were observed among methadone dose, response rate, and drug intake. The study of oral self-administration of opioid drugs by nonhuman primates may be a useful strategy for the development and evaluation of new drug substitution or replacement therapies.

Behavioral treatment of cocaine-dependent pregnant women and TB-exposed patients

Health-compromised drug-dependent patients require specialized treatment that addresses both drug use and health risks. This preliminary study examines the efficacy of a contingency management procedure (shaping) on decreasing cocaine use and increasing compliance with the prescribed treatment regimens in two health-compromised cocaine-dependent populations: (i) tuberculin (TB) exposed patients (n = 5) and (ii) pregnant women (n = 7). A multiple-baseline across-subjects design was used. There were no contingencies on cocaine use during baseline. During the contingent phase, patients received a monetary reinforcer for (a) successive decreases in the quantity of cocaine and (b) cocaine-free samples. They received a weekly reinforcer if all samples per week met criteria for (a) or (b). During the contingent phase, there was a significant decrease in cocaine metabolite levels and an increase in cocaine-free samples in both populations, with a more robust effect in the TB-exposed group. There was an increase in compliance with prenatal visits among the pregnant women during the contingent phase. Implications for health care are discussed.

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.

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.

[Control processes in speech production: flexibility and determination of event related speech planning]

The issue of our study is the flexibility of high level adjustments for the process of relating events. Our assumptions are based on the Mannheim Regulation Theory of Speech Production, in which three modes of central control are distinguished: stimulus control, schema control, and ad hoc control. Our first experiment shows that verbal accounts of an event (due to selection and construction processes) as well as the interindividual variability of this accounts (due to the control mode being less or more restricted) are strongly determined by the situational characteristics in which they are produced. In our second experiment, pressure of time is introduced into the speech production task as a disturbance factor to put some load on the attentional resources thus uncovering the flexibility vs. automaticity of the speech production process. A comparison of the results favors the assumption of verbal accounts of an event being produced by strong schematic control in a highly institutionalized situation, whereas verbal accounts of the same event in an unofficial, private situation are produced by more ad hoc planning. The results permit to psychologically reconstruct the narrating of events and the reporting of events as speech production processes which are guided by different control modes with respect to their flexibility and to their attentional demands.

Cessation of cocaine use during pregnancy: a preliminary comparison

This preliminary study examined differences between cocaine-dependent pregnant women who received "baseline" drug treatment (N = 13) and those requiring additional "intensive" treatment (N = 9). Baseline drug treatment consisted of weekly individual counseling sessions. Intensive treatment, in the form of contingency management procedures, was added for patients who showed no reduction in cocaine use during the first 4 weeks of treatment. There were no differences between the two groups in terms of demographic and pregnancy characteristics or history of cocaine use. Significantly more patients in the baseline treatment group were cocaine-free at intake and had a higher rate of compliance with scheduled prenatal clinical visits. These findings may indicate a decision to cease cocaine use prior to entering treatment, and a high degree of motivation to remain drug-free. Despite the small sample size, the finding that a substantial proportion of cocaine-dependent pregnant women remain cocaine-free during treatment is encouraging.

A menu of potential reinforcers in a methadone maintenance program

This study demonstrates the use of paired comparisons and interval scaling techniques for measuring the relative priority of program privileges available at a methadone maintenance clinic. Fifteen methadone program privileges were combined in all possible pairs (N = 105) on a reinforcer menu and administered to a group of 12 methadone patients and a second group of counselors (N = 4). Data were converted to interval scales using the law of comparative judgment to form a quantitative continuum from least to most preferable. Free methadone, free dental service, and more take-homes were ranked highest in both groups; however, patients showed less differentiation in their preference for these privileges. Dose decreases were least preferred. Results are discussed in terms of their clinical applicability in identifying privileges for potential use in modifying the behavior of drug abusers. The method of paired comparisons has excellent psychometric properties and may offer some advantages over other response scale formats.

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.

Effects of ethanol on human free-operant cooperative responding

The effects of ethanol (0.5, 0.75 and 1.00 g/kg) on human cooperative behavior were examined. Ethanol or placebo was administered 30 min before the second of five trials. During the first of two alternating schedule components, button presses were maintained by a random interval (RI) 60-s schedule of point additions to a counter marked 'Your Earnings'. During the second, Choice, component a concurrent RI 60-s schedule maintained button presses on two manipulanda. Subjects randomly assigned to the social group were instructed that they were paired with another person and could earn points working with or independently of this person. Working together, the cooperative response, simultaneously produced points on counters marked 'Other's Earnings' and 'Your Earnings'. Working independently, the independent response produced points only on the counter marked 'Your Earnings'. The other person was fictitious. The instructions for the non-social group did not mention another subject and the counter marked 'Other's Earnings' was not visible but schedule contingencies were identical to those for the social instruction group. For the social instructions group, 1.00 g/kg ethanol increased the proportion of cooperative responses and time allocated the cooperative option. For the non-social instruction group, time allocated to the topographically identical but non-social equivalent of the cooperative response decreased at the same dose. No significant between-group effects were observed following acute administration of 0.50 and 0.75 g/kg ethanol. These results suggest that the instructions established a functionally distinct social, cooperative, response which was differentially affected by ethanol.

A substance-abuse research-treatment clinic: effective procedures and systems

Drug abuse treatment clinics vary widely. This article presents a model of a research-treatment clinic in which effective procedures and systems were instituted. These systems produce an environment in which both excellent research can be conducted and effective treatment provided, by a team of researchers and clinicians. Many of the procedures overcome frequently occurring problems at drug treatment clinics. The potential applicability of these procedures and systems to standard drug treatment clinics is discussed.

Compliance with tuberculosis treatment in methadone-maintained patients: behavioral interventions

Tuberculosis has increased dramatically in the United States. Noncompliance with treatment is high. The purpose of this investigation was to achieve compliance with prophylactic TB treatment and simultaneously decrease drug use in a high-risk group of intravenous drug users. Two studies were conducted. Study 1: Subjects were 9 chronic opiate users who tested positive for tuberculosis and were placed on isoniazid (INH) and methadone. Methadone was dispensed contingent upon INH ingestion throughout. A within-subject, A-B design with contingency management interventions on drug use was implemented.

RESULTS

Compliance with INH was 100% in 8 patients. Cocaine use remained high. Study 2: Two patients, meeting same criteria as Study 1, participated in a within-subject A-B multiple baseline design. Methadone was dispensed contingent upon INH ingestion throughout. Successive decreases in cocaine use were reinforced in the contingent phase.

RESULTS

Compliance with INH was high. During contingency, both patients had over 40% cocaine-free urine samples compared with 0% at baseline. This investigation serves as a model for achieving compliance with TB treatment in opiate users.

Factor stationarity and invariance of the POMS in cocaine patients

The Profile of Mood States (POMS) factor scores are commonly used to evaluate the clinical pharmacologic effects of a drug. Two assumptions made when using the POMS in this manner are that its factor structure remains constant across time (factor stationarity) and that the factor structure is identical across experimental groups (factor invariance). If these assumptions are not met, then interpreting change in POMS factor scores becomes problematic. Structural equation modeling programs (e.g., LISREL) may be used to explicity test assumptions of factor stationarity and invariance. As part of a National Institute on Drug Abuse grant-funded, double-blind, placebo-controlled trial to assess effectiveness of treating cocaine-abusing patients with fluoxetine, POMS data were collected at baseline and at 6 weeks (n = 90). Applying a longitudinal factor analysis strategy, factor stationarity and invariance of two POMS factors were assessed in this patient sample.

Rotational behavior as a classically conditioned response to pentobarbital administration

Pentobarbital stimulus control of rotational behavior was investigated in rats with unilateral 6-hydroxydopamine lesions of substantia nigra. In conditioning trials, lesioned rats were injected simultaneously with 10 mg/kg pentobarbital and 0.05 mg/kg apomorphine and their rotational (circling) behavior observed and counted. Subsequent to three consecutive daily conditioning sessions, animals were re-introduced to the rotation environment and tested with saline or pentobarbital. Pentobarbital, but not saline, administration was followed by a brief epoch of rapid contralateral rotation. After additional conditioning trials in which pentobarbital and apomorphine administration were paired, test sessions with 1 g/kg ethanol and with 10 mg/kg chlordiazepoxide were conducted. Most animals did not rotate in response to ethanol administration and most did rotate in response to chlordiazepoxide. Finally, in order to determine the persistence of the conditioned effect, animals were tested with pentobarbital 15 weeks after their last conditioning session and were found to rotate actively in response.

Human aggressive responding during acute tobacco abstinence: effects of nicotine and placebo gum

Aggressive and point maintained operant responding of heavy nicotine dependent male tobacco smokers were measured during five 25-min sessions conducted over an 8-h period. Responding under three tobacco abstinence conditions was compared to responding during a baseline condition of ad libitum smoking of the subject's preferred brand of cigarettes. The three tobacco abstinence conditions were: (1) placebo gum, (2) nicotine gum or (3) no gum. Under placebo and nicotine gum conditions, subjects were given two pieces of placebo or 2 mg nicotine gum to chew for 30 min prior to each session. Expired air carbon monoxide (CO) levels were measured at the end of each session to monitor smoking under baseline conditions and compliance with nonsmoking requirements under abstinence conditions. Aggressive responding was increased in no gum and placebo gum conditions, with the highest frequency of aggressive responding occurring under no-gum conditions. Aggressive responding during nicotine gum conditions did not differ from baseline ad libitum tobacco smoking. Point maintained responding was either not affected or decreased under placebo and no-gum conditions. These results provided objective data consistent with clinical reports of increased irritability among dependent tobacco smokers during acute tobacco abstinence.

[Comparative studies in chronic ocular chalcosis]

Seven eyes containing a copper foreign body for a period from 8 months to 2.5 years were studied histopathologically. Foreign bodies, containing 99% copper, were in all eyes, encapsulated and located in the anterior vitreous. Characteristic features were: formation of foreign body granuloma, especially in later stages, marked fibroblastic proliferation in the vitreous with traction retinal detachment, choroidal effusion with fibrosis and foci of chronic nongranulomatous inflammation in cyclitic membranes, iris, ciliary body and sclera. Copper could be identified by rubeanic acid and rhodanine stainings in the fibrous capsule around foreign body in all eyes, in the lens capsule in one eye and in macrophages in the vitreous and retina in 2 eyes. In eyes with intravitreal haemorrhage macrophages contained also haemosiderin.

Cholinergic REM sleep induction by arecoline in normal subjects: relation to thyroid function

Serum thyroid hormones and the speed of rapid eye movement (REM) sleep induction by the central muscarinic agonist arecoline were measured in 21 normal volunteers. The arecoline-REM induction latencies had a modestly significant negative correlation with free thyroxine index. This finding is discussed in the light of observations in animal studies that thyroid hormones stimulate central cholinergic neuronal function.

Porphyria and psychosis: a case report

This article reports the case of a 41 year old female with a history of acute intermittent porphyria who presented with exacerbation of a chronic psychotic illness. Though the evaluative studies for an acute porphyric episode were negative, psychological testing was consistent with an organic patchy cognitive decline. This finding is discussed in relation to the reported assymetric neuropathic lesions reported in porphyria.

Anti-Bermuda grass RAST binding is minimally inhibited by pollen extracts from ten other grasses

This article addresses the question, Does sensitization with Bermuda grass pollen generate IgE antibodies that cross-react with other grasses? We found that none of ten non-Bermuda grass extracts attained 50% inhibition of RAST binding between sera from patients in Arizona and Bermuda-coupled disks whereas Giant Bermuda grass extract was completely cross-reactive with Common Bermuda grass.

Cocaine: an overview of current issues

A period of ascendancy of cocaine use has had implications in matters of science, public health, and national and international politics and has been the subject of numerous reviews. The present paper provides a critical overview concerning use and prevalence, and addresses a range of current issues of interest. Patterns of use, dose, tolerance, sensitization, routes of administration, and hazards of use are considered based on laboratory, epidemiological, and clinical data. Aspects of treatment are discussed. The need for developing a model of drug abuse recognizing pharmacological-neurochemical-behavioral-environmental interactions is noted. Suggestions are made concerning future directions of policy and research. The need to develop scientific goals and public policy vis-à-vis cocaine, and other stimulants, based on a historical perspective as well as current concerns is emphasized.

Exciton interaction in allophycocyanin

The absorption and circular dichroism (CD) spectra of allophycocyanin II in the trimer and monomer (dissociated) forms were resolved into four and two components, respectively. The short-wavelength region of the visible spectra was approximated by a chimera of Lorentzian- and Gaussian-shaped bands having a bandwidth of ca. 65 nm. The rest of the bands have a pure Gaussian form. The characteristic 652-nm band in the absorption spectrum (656 nm in the CD spectrum) is shown to arise from exciton interaction between two fluorescent phycocyanobilin chromophores.

Diazepam use among methadone maintenance patients: patterns and dosages

Methadone maintenance patients who use benzodiazepine drugs were interviewed about the dosage levels, patterns, frequency and motives for their use of these drugs. The sample was drawn from two treatment clinics, one in Baltimore (N = 12) and one in Philadelphia (N = 17). Benzodiazepine use was prevalent at both of these clinics - 65 -70% of maintenance patients had positive urinalysis tests during a single month. Ninety-three per cent of survey participants identified diazepam as the drug which they used most often. The median value of the usual daily dose was 40 - 45 mg; 31% reported usual daily doses between 70 and 300 mg and 62% had experience with doses of 100 mg and higher. The majority of the sample reported taking diazepam in a single daily dose within one hour of the time that they ingested their daily methadone; 72% of the sample indicated that diazepam boosts the effects obtained from the daily methadone dose. Another sample of addicts who reported extensive experience with both benzodiazepines and barbiturates indicated that diazepam increases the effects of methadone while barbiturates produce no change in the effects of methadone. Results of this study suggest that patterns and dosages of diazepam use among methadone maintenance patients are primarily abusive rather than therapeutic.

Naltrexone: a short-term treatment for opiate dependence

The narcotic antagonist, naltrexone, was studied in 242 patients during a 6-year period. Although a large number of subjects discontinued naltrexone abruptly, treatment was related to a significant decrease in opiate and nonopiate drug use. Methods for improving retention during induction and maintenance are discussed and posttreatment outcome results are presented. The authors conclude that naltrexone may be a useful short-term treatment option for opiate dependence.

Phycobilisomes from blue-green and red algae: isolation criteria and dissociation characteristics

A general procedure for the isolation of functionally intact phycobilisomes was devised, based on modifications of previously used procedures. It has been successful with numerous species of red and blue-green algae (Anabaena variabilis, Anacystis nidulans, Agmenellum quadruplicatum, Fremyella diplosiphon, Glaucosphaera vacuolata, Griffithsia pacifica, Nemalion multifidum, Nostoc sp., Phormidium persicinum, Porphyridium cruentum, P. sordidum, P. aerugineum, Rhodosorus marinus). Isolation was carried out in 0.75 molar K-phosphate (pH 6.8 to 7.0) at 20 to 23 C on sucrose step gradients. Lower temperature (4 to 10 C) was usually unfavorable resulting in uncoupling of energy transfer and partial dissociation of the phycobilisomes, sometimes with complete loss of allophycocyanin. Intact phycobilisomes were characterized by fluorescence emission peaks of 670 to 675 nanometers at room temperature, and 678 to 685 nanometers at liquid nitrogen temperature. Uncoupling and subsequent dissociation of phycobilisomes, in lowered ionic conditions, varied with the species and the degree of dissociation but occurred preferentially between phycocyanin and allophycocyanin, or between phycocyanin and phycoerythrin.

Effects of contingent payment on compliance with a naltrexone regimen

The effects of several schedules of payment on duration and patterns of compliance with a naltrexone regimen were examined. Patients were paid under contingencies based on either number of doses ingested or on a fixed time schedule. Reinforcement schedules based on number of doses ingested produced more consistent treatment-oriented behavior than a time-based schedule. Covariation between behavior and alternating contingencies (A-B-A) indicated that the schedules contributed to increased duration of treatment compared to previous noncontingent payment. The issue of using extrinsic reinforcers such as monetary payment to enhance compliance is discussed and additional procedures are suggested.