Biomedical subjects

W C Hardwick

Publications and source records attributed to W C Hardwick.

22 records · Page 2Linked to original sources

PubMed1984

Digital intubation.

Digital tracheal intubation provides a safe and efficient method of intubation when the conventional methods of endotracheal intubation are impractical or impossible. Because of difficulties encountered in the field with oral or nasal intubation, a more efficient method was sought. After paramedics were taught tactile intubation on mongrel dogs and human cadavers, the procedure was used on 66 patients in the field over a period of 20 months. Fifty-eight patients were intubated successfully using this method. In 27 of these patients, delay in airway control would have resulted if not for the institution of digital intubation. In seven cases digital intubation was unsuccessful and the patients had to be intubated by other methods. Digital tracheal intubation is a safe, rapid method of intubation and should be considered when other methods prove difficult or impossible.

Emergencies↗

PubMed1983

Effects of barbiturates in rats tolerant to delta 9-tetrahydrocannabinol.

Rats, whose behavior was maintained under a multiple fixed-ratio fixed-interval schedule of food presentation, were given delta 9-tetrahydrocannabinol (delta 9-THC), pentobarbital, barbital, and d-amphetamine before, during and after chronic delta 9-THC administration. Low doses of the barbiturates and d-amphetamine increased rates of responding, especially under the fixed-interval component. Higher doses of all four drugs decreased rates of responding under both schedule components. Tolerance developed to the rate-decreasing effects of delta 9-THC and there was cross tolerance to the rate-decreasing effects of pentobarbital and to a lesser extent barbital, but not to the rate-decreasing effects of d-amphetamine. During chronic delta 9-THC administration, rate-increasing effects of pentobarbital and barbital continued to occur, but the rate-increasing effects of d-amphetamine were attenuated. A second group of rats whose behavior was maintained under a variable-interval schedule of food presentation were given delta 9-THC and barbital before and during chronic barbital administration. Low doses of barbital increased rates of responding and higher doses of both drugs decreased rates. Tolerance developed to the rate-decreasing effects of barbital and there was cross tolerance to delta 9-THC. No tolerance developed to the rate-increasing effects of barbital. Thus, there is cross tolerance between barbiturates and delta 9-THC for rate-decreasing effects on schedule-controlled behavior, but neither tolerance nor cross tolerance occurs for rate-increasing effects.

Animals↗

PubMed1982

Phencyclidine discrimination in the pigeon using color tracking under second-order schedule.

Pigeons were trained to track different key colors, depending on whether they had been injected with phencyclidine or saline prior to the session. A second-order schedule was used to generate large numbers of responses prior to the initial food delivery. The procedure offers several advantages over traditional procedures for studying drug discrimination.

Animals↗

PubMed1980

Effects of drugs on behavior in rats maintained on morphine, methadone or pentobarbital.

Dose-effect curves were determined for the effects of drugs on responding under a multiple fixed-ratio 10-response fixed-interval 90-sec schedule of food presentation before and during chronic exposure to drugs in the drinking water. In rats consuming 70 to 90 mg/kg of morphine per day, the dose-effect curves for the rate-decreasing effects of morphine on responding under both schedule components shifted 1/2 log unit to the right, but the dose-effect curves for methadone, pentobarbital and d-amphetamine showed little change. In rats consuming 30 to 55 mg/kg of methadone per day there was little change in the dose-effect curves for the rate-decreasing effects of methadone and d-amphetamine on responding, but the dose-effect curve for morphine shifted 1/2 log unit to the right and the dose-effect curve for pentobarbital shifted upward and to the right. In rats consuming 40 to 50 mg/kg of pentobarbital per day, the dose-effect curve for the rate-decreasing effects of pentobarbital shifted to the right by about 1/4 log unit, and there was a similar but less marked shift to the methadone dose-effect curve to the right. In rats consuming pentobarbital, the morphine dose-effect curve was little changed. These experiments suggest that chronic methadone consumption confers greater tolerance to the effects of morphine on schedule-controlled behavior than it confers upon itself, while chronic morphine consumption confers greater tolerance to its own behavioral effects than it does to those of methadone. There appears to be some reciprocal cross-tolerance between methadone and pentobarbital for schedule-controlled behavior, but not between morphine and pentobarbital.

Animals↗