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Biomedical subjects

J Cleary

Publications and source records attributed to J Cleary.

At least 91 records · Page 5Linked to original sources
PubMed1984

Interval and ratio reinforcement contingencies as determinants of methadone's effects.

The effects of methadone hydrochloride on lever pressing rats maintained under multiple fixed-interval and fixed-ratio, or multiple variable-interval and variable-ratio reinforcement schedules equated for reinforcement density were examined. Under a multiple fixed-interval, fixed-ratio schedule overall response rate was decreased during both components but was most affected under the ratio schedule. Response rate decreases were due primarily to changes in running rate rather than pause time. Under a multiple variable-interval, variable-ratio schedule, overall response rate was also decreased by methadone, with the greatest decrease again occurring during the ratio schedule. These schedule-specific methadone effects are not due to differences in reinforcement frequency. Evidence for rate-dependency with methadone is not consistent across subjects.

Animals↗
PubMed1983

Discriminative stimulus properties of phenytoin in the pigeon.

Pigeons trained under a two-key drug discrimination procedure eventually learned to discriminate 5 mg/kg phenytoin from saline injections. When 1.25-20 mg/kg doses of phenytoin were substituted for the training dose, the percentage of responses directed to the phenytoin-appropriate key varied directly with dose. Chlorpromazine, d-amphetamine, diazepam, and phenobarbital failed to produce phenytoin-like patterns of responding.

Animals↗
PubMed1983

Lethality of pentazocine and tripelennamine combinations in mice housed individually and in groups.

Lethality of 80 mg/kg pentazocine alone; 40 mg/kg tripelennamine alone; 20 mg/kg tripelennamine in combination with 40, 60, and 80 mg/kg pentazocine; and 40 mg/kg tripelennamine in combination with 10, 20, and 40 mg/kg pentazocine was determined in mice housed individually and in groups. Results indicate that the lethality of pentazocine and tripelennamine combinations in mice is (1) dose-dependent, (2) potentiated relative to either drug alone, and (3) greater in group-housed than in individually-housed animals.

Animals↗
PubMed1983

Effects of pentazocine and tripelennamine on analgesia.

The analgesic effects of pentazocine and tripelennamine, alone and in combination, were assessed in rats with a hot plate apparatus. In Experiment 1, the combination of tripelennamine with chronic pentazocine produced analgesia at doses which were not analgesic when the drugs were given alone. This combination also reestablished analgesia in subjects made tolerant to pentazocine's effects. In Experiment 2, development of tolerance to the analgesic effects of pentazocine was delayed by addition of tripelennamine. These data may contribute to a rationale for the current popularity of combined pentazocine and tripelennamine abuse.

Animals↗
PubMed1981

Effects of phencyclidine on shock-induced aggression in rats.

The effects of phencyclidine were assessed under two distinctive paradigms. In a traditional laboratory assay where pairs of rats received intermittent foot shocks, phencyclidine at doses of 0.5 to 2.0 mg/kg decreased the number of shock-elicited fighting bouts in dose-dependent fashion. Similar dose-dependent decreases in biting were also observed under a procedure where single restrained rats received intermittent tail shocks, which evoked biting of an inanimate target.

Aggression↗
PubMed1981

d-Amphetamine and phencyclidine alone and in combination: effects on fixed-ratio and interresponse-time-greater-than-t responding of rats.

The effects of three doses of d-amphetamine (0.5, 1.0, and 2.0 mg/kg) and phencyclidine (0.5, 1.0, and 2.0 mg/kg), alone and in combination, were assessed in rats performing under fixed-ratio 30 and interresponse-time-greater-than-15-sec food reinforcement schedules. When given alone, phencyclidine and d-amphetamine produced similar increases in responding under the interresponse-time-greater-than-t schedule, and decreases in responding under the fixed-ratio 30 schedule. Each drug decreased the number of reinforcers (food pellets) earned relative to control values under both schedules. The effects of the two drugs in combination were nearly always less than additive. That is, the effects of a given dose of phencyclidine and d-amphetamine together were less than an arithmetic summation of the effects of the drugs given alone.

Animals↗
PubMed1981

Chlorpromazine effects on behavior under escape and fixed-time delivery of shock.

Chlorpromazine has typically been found to reduce responding maintained by negative reinforcement. In squirrel monkeys, however, it has been shown to increase manipulative responses that occur just prior to shock presented under a fixed-time schedule. The present study compared chlorpromazine effects on behavior of rats under a fixed-time schedule of shock delivery and a schedule involving escape from shock. In all conditions, shock was delivered to the tail of rats held in partial restraint, and the response measured was displacement of a panel positioned directly in front of the rat's nose. The escape and fixed-time schedules generated similar temporal patterns and rates of responding under both schedules, and had no differential effect on the temporal distribution of responses within the shock interval.

Animals↗
PubMed1981

Burying by rats in response to aversive and nonaversive stimuli.

Previous investigations have shown that rats bury a variety of conditioned and unconditioned aversive stimuli. Such burying has been considered as a species-typical defensive reaction. In the present studies, rats buried spouts filled with Tabasco sauce, or condensed milk to which a taste aversion was conditioned, but did not bury water-filled spouts or spouts filled with a palatable novel food (apple juice) to which a taste aversion was not conditioned. However, in other experiments rats consistently and repeatedly buried Purina Rat Chow, Purina Rat Chow coated with quinine, and glass marbles. This indicates that a variety of stimuli, not all aversive or novel, evoke burying by rats. Whereas the behavior may reasonably be considered as a species-typical defensive behavior in some situations, the wide range of conditions that occasion burying suggests that the behavior has no single biological function.

Journal Article↗
PubMed1980

The use of human observers in psychopharmacological research.

During 1974-1978, over 40% of the nonhuman drug studies that appeared in Psychopharmacology, Pharmacology Biochemistry and Behavior, and Journal of Pharmacology and Experimental Therapeutics involved human observers; far fewer studies published in Journal of the Experimental Analysis of Behavior did so. In all of these journals, measures of interobserver agreement seldom were provided. The great majority of studies also failed to utilize one or more "blind" observers, unaware of experimental conditions. These findings are of interest in light of reports that observational data are affected by a wide range of factors and often provide an inaccurate index of behavior. The believability of observational data seemingly is enhanced by careful descriptions of recording procedures coupled with the use of two or more blind observers whose concordance in rating behavior has been determined. These procedures characteristically are followed in some behavioral sciences, such as applied behavior analysis, but not to the same degree in psychopharmacology.

Animals↗
PubMed1979

Low-friction arthroplasty for healed septic and tuberculous arthritis.

Forty hips, which had previously been the site of tuberculous or pyogenic arthritis and which had later developed a degenerative arthritis, were treated by low-friction arthroplasty some forty years after the original infection. The results suggest that, when healing of the primary infection has been followed by a long period of quiescence with acceptable function before the onset of degenerative change, the arthroplasty can be confidently expected to result in greatly improved function and that this improvement is long-lasting.

Adult↗
PubMed1975

The child and the snowmobile.

From November 1970 through March 1975, 41 children in Manitoba required hospitalization for treatment of injuries sustained in snowmobile accidents. The commonest injuries were fractures of a leg. In general, the injuries were severe, and in many instances the fractures were unusualy and uncommonly seen in children. Most often the child had been driving the snowmobile and all injuries were a result of driver error or misadventure; none was due to malfunction of the snowmobile. Recommendations to minimize the number and severity of snowmobiling injuries in children include an education program for both adults and their children, use of lightweight cowling to protect the legs, incorporation of a governor on the throttle to prevent excessive speeds, and use of a restraint for children travelling as passengers on the snowmobile. Children should always wear tight clothing when around snowmobiles.

Accident Prevention↗
PubMedDate not supplied

Retinal development of West Australian dhufish, Glaucosoma hebraicum.

An investigation of retinal specializations was carried out in larval and juvenile dhufish, Glaucosoma hebraicum (Glaucosomidae, Teleostei). The development of photoreceptors and formation of the retinal mosaic was followed by light and electron microscopy. At hatching the eye was undifferentiated. Cone photoreceptors were present by day 3 posthatch (dph), when exogenous feeding began. Single and multiple cones were present in a row arrangement from 3 dph to 20 dph, when the first rod nuclei were observed. Between 20 dph and approximately 3 months posthatch (mph), the row arrangement was replaced by a square mosaic of four double cones surrounding a single cone, and the cones increased in size, with the outer segments reaching up to 30 microm in length. During the period of spatial rearrangement, triple cones were often observed. From their first appearance, rod photoreceptors were added rapidly. Investigation of ganglion cell topography in 3-mph fish that had attained the adult-like square photoreceptor mosaic was carried out using retinal wholemounts. The highest densities of neurones in the ganglion cell layer were in temporal retina but no well-defined area centralis was observed. Microspectrophotometric measurements of the visual pigments within the outer segments of the photoreceptors of 3-mph fish revealed double cones with identical absorption spectra in each member of the outer segment, and the wavelength of maximum absorption (lambda(max)) located at 522 nm. Single cones were found to possess a visual pigment with lambda(max) at 460 nm and rods with a lambda(max) of 498 nm. The results imply that the larvae and juveniles are adapted for survival in coastal waters and may be active in relatively low light levels from early stages of development.

Animals↗