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Biomedical subjects

L S Lester

Publications and source records attributed to L S Lester.

6 recordsLinked to original sources
PubMed1995

Validation of daily self-reported alcohol consumption using interactive voice response (IVR) technology.

OBJECTIVE: This study assesses the validity of daily self-reported drinking data obtained using an automated touch-tone interactive voice response (IVR) system. METHOD: Subjects (N = 30) reported alcohol consumption daily for 28 days using the IVR system. Concurrently, breath and saliva samples were obtained each night for objective determination of blood alcohol concentrations (BACs). Partners living with the subjects provided collateral reports daily. Retrospective drinking records were obtained from both partners at the outset of the study and from the target subjects at the end of the study, using timeline follow-back procedures referencing the target subjects' drinking over the previous 28-day period. RESULTS: Subjects reported drinking on 55.2% of the 840 possible subject days, and positive BAC readings were obtained on 25.9% of these days. The overall correlation between self-report and measured BAC was .72. Within-subject correlations between daily IVR reports and measured BACs ranged from -.07 to .92, with a mean of .57. The correlations between self-reported drinking and the collateral reports ranged from .18 to 1.0, with a mean of .89. Correlations between the daily self-reports and the timeline follow-back records obtained at the end of the study ranged from -.22 to .96, with a mean of .51. CONCLUSIONS: IVR technology provides an innovative, user-friendly methodology for obtaining valid measures of daily alcohol consumption. The validity of these measures may be differentially highest for frequent, heavy drinkers, a group for whom traditional assessment methods often produce the most biased underestimates.

Adult↗
PubMed1992

Age-related differences in recovery from simulated jet lag.

Six healthy young men and eight early middle-aged men were isolated from environmental time cues for 15 days. For the first 6-7 days (one or two nights adaptation, four nights baseline), their sleep and meals were scheduled to approximate their habitual patterns. Their daily routines were then shifted 6 hours earlier by terminating the sixth or seventh sleep episode 6 hours early. The new schedules were followed for the next 8 or 9 days. Important age-related differences in adjustment to this single 6-hour schedule shift were found. For the first 4-day interval after the shift, middle-aged subjects had larger increases of waking time during the sleep period and earlier termination of sleep than young subjects. They also reported larger decreases in alertness and well-being and larger increases in sleepiness, weariness and effort required to perform daily functions. The rate of adjustment of the circadian core temperature rhythm to the new schedule did not differ between groups. These results suggest that the symptoms reported by the middle-aged subjects may be due mainly to difficulty maintaining sleep at early times of the circadian day. The compensatory response to sleep deprivation may also be less robust in middle-aged individuals traveling eastbound.

Adolescent↗
PubMed1991

Acceptability and effect of carbohydrate-electrolyte solutions on electrolyte homeostasis during field training.

Two lemon-lime flavored 2.5% carbohydrate-electrolyte solutions (CE1 supplemented with Na+, K+, and Mg+; and CE2 supplemented with NA+) were compared to plain water (water) and lemon-lime flavored water placebo (placebo) to evaluate their acceptability and consumption during 8 days of field training in hot weather. Acceptability ratings and consumption of CE2 and the flavored water placebo were similar and greater, respectively, than those for CE1. Average Na+ and K+ intakes, and serum electrolytes levels, were not affected during the 8-day trial. If food intake is adequate, consumption of carbohydrate-electrolyte solutions is apparently unnecessary to maintain electrolyte homeostasis.

Carbohydrates↗
PubMed1988

Changes in feeding and foraging patterns as an antipredator defensive strategy: a laboratory simulation using aversive stimulation in a closed economy.

The effects of the risk of electric shock on the meal patterns of rats living in an operant chamber were investigated. Rats could obtain food by working on a response lever that provided reinforcement according to chained fixed-ratio continuous reinforcement schedules that allowed the animals control over meal size. Using a two-compartment operant chamber with a safe nesting area and manipulanda area with a grid floor, shock could be correlated with responding on the schedule. Shocks (less than or equal to 1.25 per hour) were scheduled to occur randomly throughout the day, independent of the rat's behavior. Shock caused a reorganization of meal patterns such that the animals took less frequent but larger meals. This pattern reduced the time the animals spent at risk without compromising caloric balance. Similar changes in feeding pattern were obtained in both hooded and albino rats. Exposure to shock in a separate chamber did not produce these behavioral modifications. The magnitude of shock-induced alterations of meal patterns was greater with chained fixed-ratio 90 continuous reinforcement than with chained fixed-ratio 10 continuous reinforcement. Additionally, the rats seemed to be able to reduce food intake but increase caloric efficiency, such that the reduced food intake did not have deleterious effects on maintenance of body weight. These behavioral modifications reduced the number of shocks received from that which would have been expected if meal pattern changes had not occurred. We suggest that this technique may provide a useful laboratory simulation of the impact that the risk of predation has on foraging behavior.

Animals↗
PubMed1985

Exposure to a cat produces opioid analgesia in rats.

Two experiments were conducted to test the prediction that rats should react with reduced sensitivity/reactivity to nociceptive stimulation in the presence of a cat. In Experiment 1, naloxone or saline was administered, and rats were exposed to no stimulus, a novel stimulus, or a cat. In Experiment 2, rats were exposed to either no stimulus or a cat, and naltrexone was administered. In both experiments, rats tested in the presence of the cat showed a significant reduction in sensitivity/reactivity to a skin-irritating formalin injection. Naltrexone reversed this analgesia.

Animals↗