Biomedical subjects

K L Preston

Publications and source records attributed to K L Preston.

115 records · Page 7Linked to original sources

PubMed1981

The aversive stimulus properties of repeated infusions of cocaine.

When the presentation of a novel food to a rat is followed by the administration of certain compounds, including psychomotor stimulants, the animal consumes less of the food on subsequent presentations relative to an animal administered saline. This phenomenon has been termed gustatory avoidance conditioning. Conflicting results have been obtained when cocaine is used in this procedure. Therefore, the possibility that the weak efficacy of cocaine in this paradigm is due to its relatively short duration of action was investigated. Fluid intake was limited to a single 15 min presentation, seven days a week. Following the determination of baseline water in take sweetened milk was given during the session followed by a series of infusions of cocaine through chronic indwelling peritoneal catheters. Four infusions, spaced 15 min apart, of 9.0 mg/kg cocaine induced an avoidance response, while one infusion of 36 mg/kg cocaine followed by three saline infusions did not. This supports the hypothesis that the low efficacy of cocaine in this paradigm is due, at least in part, to its short duration of action.

Animals↗

PubMed1978

Phencyclidine-induced stereotyped behavior in monkeys: antagonism by pimozide.

The psychotomimetic substance, phencyclidine (PCP), was administered chronically to selected members of a primate social colony. PCP induced stereotyped behavior in all treated monkeys at each of three test doses. Furthermore, there was a significant increase in the amount of stereotypy seen during the second and third weeks of treatment compared to the first week. The dopamine receptor blocking agent pimozide antagonized PCP stereotypy. The results are discussed in terms of dopamine mediation of these responses.

Animals↗

PubMedDate not supplied

A model for pharmacological research-treatment of cocaine dependence.

Major problems for research on pharmacological treatments for cocaine dependence are lack of comparability of results from different treatment research programs and poor validity and/or reliability of results. Double-blind, placebo-controlled, random assignment, experimental designs, using standard intake and assessment procedures help to reduce these problems. Cessation or reduction of drug use and/or craving, retention in treatment, and medical and psychosocial improvement are some of the outcome variables collected in treatment research programs. A model to be followed across different outpatient clinical trials for pharmacological treatment of cocaine dependence is presented here. This model represents an effort to standardize data collection to make results more valid and comparable.

Cocaine↗

PubMedDate not supplied

Optimal bowel preparation for flexible sigmoidoscopy--are two enemas better than one?

Recommendations regarding optimal bowel preparation for fiberoptic flexible sigmoidoscopy remain anecdotal and inconclusive. We prospectively evaluated three commonly recommended regimens for administering hypertonic phosphate enemas to subjects undergoing 60-cm fiberoptic flexible sigmoidoscopy for routine indications. Patients were randomly assigned to one of three hypertonic phosphate enema regimens. Group A received one enema 1 hour before fiberoptic flexible sigmoidoscopy, group B received two enemas 1 hour before, and group C received one enema 3 hours before and a second enema 1 hour before fiberoptic flexible sigmoidoscopy. Adequacy of bowel preparation was graded as excellent, adequate, or poor. Results revealed no statistically significant difference in the adequacy of bowel preparation between the three regimens, all resulting in adequate or excellent preparation in approximately 80% of patients. We recommend the use of one hypertonic phosphate enema 1 hour before routine fiberoptic flexible sigmoidoscopy. Implementation of this recommendation is efficacious, convenient for patients, and cost-effective.

Double-Blind Method↗

PubMedDate not supplied

Occurrence of cocaine in urine of substance-abuse treatment patients.

As part of ongoing research efforts to improve methods of monitoring drug use in treatment patients, the presence of cocaine in urine specimens was evaluated as a possible marker for recent illicit cocaine use. A total of 2327 urine specimens collected during a 17-week clinical trial of a cocaine-abuse treatment study were tested. Cocaine was measured by gas chromatography-mass spectrometry, and benzoylecgonine (BZE) equivalents were determined by fluorescence polarization immunoassay (FPIA). More than one-third of the specimens were positive (> 25 ng/mL) for cocaine (36.8%), and nearly two-thirds were positive (> 300 ng/mL) for cocaine metabolite by FPIA (62.7%). Median concentrations of cocaine and BZE equivalents were 235 and 14,900 ng/mL, respectively, and maximum concentrations were 112,025 and 1,101,190 ng/mL in cocaine- and BZE-positive specimens, respectively. There were 52 specimens that contained cocaine in equal or higher concentrations than BZE equivalents. No significant differences in cocaine or BZE concentrations between Caucasian and African-American or between male and female patients were found. Cocaine was present less frequently and at lower concentrations than BZE but more frequently than expected based on an average half-life of approximately 1 h, which suggests that cocaine may exhibit a longer terminal half-life and/or that accumulation of cocaine can occur in chronic, heavy users.

Adolescent↗

PubMedDate not supplied

Pharmacological advances in addiction treatment.

In the past 20 years significant advances in the pharmacological treatment of opioid dependence have been made, and research in this area is continuing. Therapeutic applications and current research in the use of pharmacological agents in maintenance therapy, treatment with narcotic antagonists, and narcotic detoxification are discussed. In addition, an overview is presented of recent developments in opioid pharmacology and of recently developed novel pharmacological agents which may prove useful in the future treatment and/or prevention of opioid dependence.

Benzodiazepines↗

PubMedDate not supplied

Side effects of triazolam in children.

PURPOSE: This study examined the incidence of side effects occurring with three doses of orally administered triazolam in children undergoing restorative dental procedures. METHODS: Thirty children, aged 39-81 months, participated in the study. The children were pretested for gait ataxia, amnesia, visual acuity, stereoscopic depth perception, and diplopia during a screening session. In a subsequent appointment, children received one of three triazolam dosages (0.005, 0.015, and 0.030 mg/kg) prior to dental treatment. Dosage assignment was random and double blind. Each child received a single triazolam dosage. Tests for gait ataxia, amnesia, and visual disturbances were repeated following drug administration. RESULTS: The proportion of children experiencing ataxia, amnesia, and diplopia increased with increasing triazolam dosages. The 0.030-mg/kg triazolam dosage impaired visual acuity and stereoscopic depth perception. CONCLUSION: Triazolam produces ataxia, amnesia, and diplopia in a dose-dependent manner in children.

Administration, Oral↗