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Biomedical subjects

V R Hunt

Publications and source records attributed to V R Hunt.

17 recordsLinked to original sources
PubMed1994

Effects of concurrent saccharin availability and buprenorphine pretreatment on demand for smoked cocaine base in rhesus monkeys.

The effects of saccharin and the opioid partial agonist buprenorphine on cocaine base smoking were evaluated in five male rhesus monkeys. Monkeys completed a sequence of responding consisting of lever-press responses maintained under a fixed-ratio (FR) schedule followed by inhalation responses (FR5) on a smoking spout to gain access to a single delivery of volatilized cocaine base (1.0 mg/kg per delivery). Monkeys could receive a maximum of ten smoke deliveries per session. In the first experiment, either saccharin (0.03% wt/vol) or water was concurrently available under an FR1 schedule through a lip-operated drinking device. As lever FR values increased from 128 to 256, 512, 1024 and 2048, the number of cocaine smoke deliveries decreased. Cocaine intake was not statistically different when water versus saccharin was concurrently available. However, as cocaine consumption decreased, saccharin intake increased demonstrating that under these conditions, saccharin was substituting for cocaine as a reinforcer. On the first day that lidocaine replaced cocaine, all of the monkeys received the maximum number of smoke deliveries (ten) and saccharin intake increased. Lever-press responding gradually extinguished over days when lidocaine (1.0 mg/kg per delivery) was available with concurrent saccharin. In the second experiment, water was concurrently available with cocaine and buprenorphine (0.01 or 0.1 mg/kg) was administered intramuscularly (IM) 30 min before the start of the session. Although pretreatment with the lower dose of buprenorphine (0.01 mg/kg) had little effect on cocaine intake overall, individual differences in cocaine intake occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1981

Epidemiological studies for regulatory agencies.

In regulation of exposures to hazardous environmental agents, epidemiologic evidence is especially important in defining human risk estimates. The process of developing appropriate regulations is complex, however, and depends on many considerations beyond those established to a high degree of scientific certainty. Thus the needs of regulatory agencies are involved in the way epidemiologic data are developed and presented. To coordinate and review common problems associated with preventive and regulatory activities among the federal agencies concerned with regulation, an Interagency Regulatory Liaison Group (IRLG) was established in 1977. Because of difficulties encountered by these agencies or Congressional committees in evaluating epidemiologic evidence, a subcommittee of the IRLG has developed in draft form guidelines for human population studies to be used in public health decision-making. Although these guidelines have attracted much controversy, their aim is to present criteria for design and documentation of epidemiologic studies, without interfering with the initiative of investigators. Some aspects of the IRLG guidelines are discussed. The need for epidemiologic research in providing evidence for regulatory purposes is increasing, but such studies must be well done if they are to be useful.

Epidemiologic Methods↗
PubMed1969

Maximum expiratory flow rates in induced bronchoconstriction in man.

We evaluated changes of maximum expiratory flow-volume (MEFV) curves and of partial expiratory flow-volume (PEFV) curves caused by bronchoconstrictor drugs and dust, and compared these to the reverse changes induced by a bronchodilator drug in previously bronchoconstricted subjects. Measurements of maximum flow at constant lung inflation (i.e. liters thoracic gas volume) showed larger changes, both after constriction and after dilation, than measurements of peak expiratory flow rate, 1 sec forced expiratory volume and the slope of the effort-independent portion of MEFV curves. Changes of flow rates on PEFV curves (made after inspiration to mid-vital capacity) were usually larger than those of flow rates on MEFV curves (made after inspiration to total lung capacity). The decreased maximum flow rates after constrictor agents are not caused by changes in lung static recoil force and are attributed to narrowing of small airways, i.e., airways which are uncompressed during forced expirations. Changes of maximum expiratory flow rates at constant lung inflation (e.g. 60% of the control total lung capacity) provide an objective and sensitive measurement of changes in airway caliber which remains valid if total lung capacity is altered during treatment.

Acetylcholine↗