Search PubMed⌕ Search

Biomedical subjects

C P O'Brien

Publications and source records attributed to C P O'Brien.

At least 181 records · Page 10Linked to original sources
PubMed1983

Cynomolgus monkeys do not develop tolerance to opioids.

In order to examine the development of tolerance to opioids, eight cynomolgus and two rhesus monkeys were trained to press a lever for food reinforcement and then were catheterized so that drugs could be infused. Three doses of hydromorphone and six different interdose intervals were studied. Hydromorphone infusions initially suppressed lever pressing for food in both species. The rhesus monkeys acquired tolerance to these sedative effects after 14 exposures to the opioid. However, the cynomolgus monkeys failed to acquire tolerance after more than 100 exposures. Naloxone challenge elicited withdrawal symptoms from the rhesus monkeys but not from the cynomolgus monkeys. This differential response to sustained opioid administration in these closely related species suggests that a genetic mechanism may underlie tolerance to and physical dependence on opioids.

Animals↗
PubMed1983

Increased effectiveness of substance abuse treatment. A prospective study of patient-treatment "matching".

An earlier study retrospectively evaluated the effectiveness of six separate substance abuse treatment programs and generated a set of hypotheses for matching patients to the most appropriate programs. In the present study, these predictors and the matching strategy were tested in a prospective design, using the same treatment programs and a new sample of 130 alcohol- and 256 drug-dependent patients. The new group of patients who were treated in their predicted program (matched patients) were compared with those patients from the same sample who were not treated in their predicted program (mismatched patients). Treatment staff were not apprised of the matching criteria or which patients were matched, thus permitting an experimental test of the predictions. Results indicated superior performance during treatment and an average of 19 per cent better 6-month outcomes for the matched patients than for their mismatched counterparts. The matching effect was seen in both the alcohol- and drug-dependent samples and in all treatment programs. The authors discuss the application of these findings to other types of patients and treatments in substance abuse and other fields of psychiatry.

Alcoholism↗
PubMed1983

Psychotherapy for opiate addicts.

An opportunity to receive a six-month course of professional psychotherapy in addition to paraprofessional counseling was offered to opiate addicts who were beginning a new treatment episode on a methadone maintenance program. The treatments offered were drug counseling alone (DC), counseling plus supportive-expressive psychotherapy (SE), or counseling plus cognitive-behavioral psychotherapy (CB). Sixty percent of patients meeting the study criteria expressed an interest in the psychotherapy program and 60% of these actually became engaged. One hundred and ten subjects completed the study intake procedure, were randomly assigned to one of the three treatment conditions and kept three or more appointments within the first six weeks of the project. A variety of outcome measures showed that patients in all three treatment groups improved. Patients receiving the additional psychotherapies improved in more areas and to a greater degree than those who received counseling alone. The specific improvements seen appear to be related to the focus of the therapy used. Patients with antisocial personality disorder, as defined by Research Diagnostic Criteria, did not benefit significantly from therapy, but those with depression did. Patients with high levels of psychiatric symptoms made many significant gains if they received additional therapy, but improved only in drug use if they received counseling alone. Patients in all three treatment groups having low levels of psychiatric symptoms improved significantly in many areas. We conclude that more than a third of opiate addicts in our treatment program are interested in psychotherapy and many of these can benefit from it. Certain administrative procedures appear necessary to maximize the chances that psychotherapy can be used effectively with drug addicted patients.

Adult↗
PubMed1982

Is treatment for substance abuse effective?

Few studies have assessed adequately the effectiveness of alcohol and drug abuse treatments using an appropriate range of reliable outcome measures, a representative sample of alcohol and drug abuse treatment modalities, or more than one perspective on treatment effectiveness. This article evaluates substance abuse treatment using a sample of 742 patients treated in six programs and evaluated at six-month follow-up. The following three major questions were addressed: (1) do patients improve following treatment; (2) are improvements confined to alcohol or drug use, or are they more pervasive; and (3) are these improvements a result of treatment? The results indicated significant and pervasive improvements in virtually all areas for both alcoholics and drug addicts. Major changes were seen in alcohol and drug use, employment, criminal behavior, and psychological function. Patients undergoing long-term treatment showed greater improvement and better six-month outcomes than those undergoing short-term therapy on 12 of 18 criteria. The data provide evidence for the therapeutic benefit of substance abuse treatments.

Alcoholism↗
PubMed1982

Propoxyphene and norpropoxyphene kinetics after single and repeated doses of propoxyphene.

Plasma concentrations of propoxyphene (P) and its pharmacologically active metabolite norpropoxyphene (NP) were determined in normal subjects after single 130-mg oral doses and during and after 13 consecutive oral doses of 130 mg P, and in former heroin addicts who were maintained on 900 to 1200 mg of P per day. The data were analyzed using a first-pass elimination pharmacokinetic model. Both P and NP cumulated during repeated dosing to levels 5 to 7 times those after the first dose. In contrast, "maintenance" patients exhibited steady-state trough plasma NP cumulation that exceeded that of P by a factor of 13. Several changes in P and NP kinetics occurred during repeated dosing with P to the normal subjects: P clearance decreased from 994 to 508 ml/min, NP clearance decreased from 454 to 2210 ml/min, P half-life (t 1/2) increased from 3.3 to 11.8 hr, NP t 1/2 increased from 6.1 to 39.2 hr, and area under the concentration time curves for P and NP were doubled. These changes in kinetics during repeated dosing resulted in more extensive cumulation of P and NP than would be predicted from the single-dose kinetic profile. Changes in the extent of first-pass elimination of P result in variability in plasma P and NP that may contribute to P-induced toxicity.

Adult↗
PubMed1982

Absence of naloxone sensitivity in obese humans.

Studies in rodents suggest the possibility of an association between elevated endogenous opiate activity and overeating and obesity. One measure of elevated opiate activity is sensitivity to the opiate antagonist naloxone. Seven massively obese human subjects showed no subjective or physiological sensitivity to large intravenous doses of naloxone. This finding fails to support a relationship between elevated endorphin activity and human obesity.

Arousal↗
PubMed1982

The relation of plasma androgen levels to sexual behaviors and attitudes of women.

Four androgens: dehydroepiandrosterone (DHEA), androstenedione (A), testosterone (T), and dihydrotestosterone (DHT), a variety of sexual behaviors and attitudes, and several moods were determined regularly in two groups of healthy, married women who differed by three decades in age. The younger women exhibited significantly higher levels of each androgen, the differences being almost entirely attributable to ovarian failure in the older group. Although the older women reported the same levels of sexual desire and sexual arousal as the younger women, their intercourse frequencies and self-rated sexual gratification scores were significantly lower than the values obtained for the younger wives. One or more of the androgen levels related significantly and in the expected direction to each stage of the four-stage sexual response process. Global measures of so-called "sexual adjustment" and estimates of anxiety, depression, and hostility feelings experienced by these women did not relate significantly to any of the four androgen levels.

Adult↗
PubMed1982

Endorphin levels in opioid-dependent human subjects: a longitudinal study.

Endorphin levels were measured in 51 cerebrospinal fluid samples from 27 opioid-dependent or postdependent subjects. Radioreceptor assay showed the endorphin levels to be higher than those found in normal subjects. These high levels were found even while subjects were on methadone maintenance. The duration of opioid dependence was positively correlated with fraction I values. Both fractions tended to be lower during early withdrawal than late withdrawal. In naltrexone-maintained patients, radioreceptor assay showed FII to be greatly elevated, but electrophoresis and HPLC indicated that the elevations were not due to a peptide. Thus, the possibility of unextracted naltrexone metabolites remains at least a partial explanation for this apparent FII elevation.

Adult↗