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Biomedical subjects

G K Beauchamp

Publications and source records attributed to G K Beauchamp.

At least 73 records · Page 4Linked to original sources
PubMed1992

Cocaine-exposed newborns show an exaggerated sucking response to sucrose.

The sucking responses of 16 newborn infants exposed to cocaine just prior to birth and 16 control newborns were recorded when offered a fluidless sucrose-flavored nipple and a comparable nonsweet nipple. Cocaine-exposed infants showed a significantly greater preference for sweet taste: Compared with control infants, the cocaine group sucked more frequently when offered the sweet nipple and less frequently when presented with the nonsweet nipple. This heightened response to sweet stimulation might reflect (i) a coping mechanism for the perinatal distress of intrauterine cocaine-exposure since sweet taste appears to alleviate distress via an opioid mechanism; and/or (ii) altered dopaminergic activity in a common neuronal pathway that mediates the rewarding aspects of both cocaine and sweet taste.

Cocaine↗
PubMed1992

Assessing odor generalization in the rat: a sensitive technique.

In investigating the ability of the rat to discriminate among urine odors from mice of different genetic strains, we developed a technique for determining the extent of odor generalization. Trained rats performed a discrete trial, go/no-go procedure, touching a bar in the presence of an S+ odor for water reward. Rats easily learned this task and restricted their responding to trials with the S+ stimulus, even though there was no penalty for responding to S-. However, when presented with test stimuli that might be more similar to S+ or S-, some rats responded only to the S+, and not at all to S- or any generalization stimuli. We then created series of stimuli composed of different levels of adulteration of the S+ stimulus with generalization stimuli. With these stimuli, rats produced graded levels of responding, allowing comparisons of similarity among odorant stimuli. This technique can be applied to other types of odorant stimuli, particularly biological compounds of unknown concentration or purity, and should be of use in an operant laboratory studying odorant perception, or odorant characteristics.

Animals↗
PubMed1992

Short-term effects of diet on salt taste preference.

The purpose of this experiment was to determine whether optimal salt levels in soup were influenced by consumption of a meal either high or low in salt. Following a lunch high in salt, optimal salt levels were reduced; no change in optimal levels followed a lunch low in salt. No changes in optimal sweet preference were observed for either condition. It is suggested that changes in optimal salt levels are due to factors associated with exposure to salt during the meal.

Adult↗
PubMed1992

Developmental changes in nasal airflow patterns.

Airflow through each nasal passage was measured every 10 min throughout a 5-h period in 48 subjects whose ages ranged from 3 to 17 years. The data were subjected to statistical techniques that characterize and quantify periodicities in a time series. Such analyses revealed that for the majority of children younger than 7 years of age, the airflow through the two nostrils changed either randomly (50%) or in parallel (31%). Between the ages of 7 and 10 years, however, the distribution of airflow patterns characteristic of adults emerged, such that the incidence of reciprocity increased to 63%, and the incidence of random and parallel patterns decreased to 31% and 6%, respectively. A similar distribution was evidenced in the 11- to 17-year-old subjects (56% reciprocal, 38% random, 6% parallel). Although the total airflow through the nose also increased with age, the increased inspiratory flow rates could not account for the developmental changes evidenced in airflow patterns.

Adolescent↗
PubMed1991

The transfer of alcohol to human milk. Effects on flavor and the infant's behavior.

BACKGROUND: The amount of alcohol ingested by a breast-fed infant is only a small fraction of that consumed by its mother, but even this small amount may have an effect on the infant. We investigated whether the ingestion of alcohol by a lactating woman altered the odor of her milk and whether exposure to a small amount of alcohol in the mother's milk had immediate effects on the behavior of the infant. METHODS: Twelve lactating women and their infants were tested on two days separated by an interval of one week. On each testing day, the mother expressed a small quantity of breast milk and then drank either orange juice or orange juice containing a small quantity of ethanol (0.3 g per kilogram of body weight). Additional milk samples were obtained at fixed intervals after the ingestion of the beverage and analyzed to determine their ethanol content. The samples were also evaluated by a panel of adults to determine whether any difference in the odor of the milk was detectable after alcohol ingestion. The infants were weighed before and after nursing to assess the amount of milk they ingested, and their behavior during breast-feeding was monitored by videotape. RESULTS: Short-term alcohol consumption by lactating women significantly and uniformly increased the perceived intensity of the odor of their milk as assessed by the panel; this increase in the intensity of the odor peaked 30 minutes to 1 hour after the alcohol was consumed and decreased thereafter. The alteration in the odor of the milk closely paralleled the changes in the concentration of ethanol in the milk (mean range, 0 to 6.9 mmol per liter [0 to 32 mg per deciliter]). The infants sucked more frequently during the first minute of feedings after their mothers had consumed alcohol (67.0 +/- 6.5 sucks, as compared with 58.4 +/- 5.9 sucks for feedings after the consumption of the nonalcoholic beverage; P less than 0.05), but they consumed significantly less milk (120.4 +/- 9.5 ml vs. 156.4 +/- 8.2 ml, P less than 0.001) during the testing sessions in which their mothers drank the alcoholic beverage. CONCLUSIONS: Although the mechanisms underlying this reduction in milk intake remain to be elucidated, this study shows that short-term alcohol consumption by nursing mothers has an immediate effect on the sensory characteristics (odor) of their milk and the feeding behavior of their infants.

Adult↗
PubMed1991

Human development and umami taste.

Previously we demonstrated that in very brief, one-bottle intake tests, human infants, both well nourished and protein calorie malnourished, ingested greater amounts of soup with added MSG compared with soup alone. The potentiating effect of MSG in plain aqueous solution was tested in the current experiments. In contrast to data with sucrose and salt solution, where infants preferentially ingest these compounds compared with a water diluent, aqueous MSG solutions were rejected relative to water. The implications of this observation for understanding the mechanisms of MSG perception and pleasantness were discussed.

Child Development↗
PubMed1991

Naltrexone, an opioid blocker, alters taste perception and nutrient intake in humans.

To test the hypothesis that reduced food intake produced by opioid blockade is due to a reduction in the pleasant aspects of tastes, 18 fasted male college students rated the intensity and pleasantness of soup that contained various concentrations of NaCl and of Kool-Aid that contained various concentrations of sucrose at hourly intervals after ingesting either naltrexone (50 mg) or a placebo in a double-blind study. Hunger, fullness, nausea, and current mood state were also assessed. Lunch followed and food intake was recorded. After placebo, the pleasantness of the salted soup increased as lunchtime approached. After naltrexone, however, soup pleasantness remained unchanged across time. Similar changes were obtained for perceived sweetness and pleasantness of Kool-Aid and for the perceived saltiness of soup. Naltrexone also blocked the increases in hunger ratings that occurred across time in the placebo condition. Nausea was higher after naltrexone. After naltrexone, subjects consumed approximately 500 kcal less at lunch than after placebo. Analysis of covariance suggested that decreased hunger (but not nausea or taste pleasantness) accounted for the naltrexone-induced reduction of food intake.

Adult↗
PubMed1991

High salt intake. Sensory and behavioral factors.

Salt (NaCl) is a ubiquitous component of diets in developed countries. A major reason for this is that people judge many salted foods as more palatable than the same foods without salt. Because recent evidence indicates that an acceptable salt substitute is unlikely, an understanding of the behavioral and sensory factors involved in maintaining high salt preference is a prerequisite to successful programs aimed at reducing intake. Although little evidence exists for a genetic determination of individual differences in consumption and preferred level of salt, more research in this area is necessary. Considerable data support the view that the optimal level of salt in the diet is determined in part by the level an individual is currently consuming; increasing or decreasing customary salt intake, as long as the salt is tasted, increases or decreases the preferred level of salt in food. Although these data are consistent with a hypothesis that optimal salt preferences are learned, other data, from both animal models and human developmental studies, suggest that salt preference has an innate component. Furthermore, early experience with low or high salt diets may have a long-term impact on preferred salt levels. Liking for salt, similar to liking for sweets, has an innate basis that can be modified by individual experience.

Behavior↗
PubMed1991

Maternal diet alters the sensory qualities of human milk and the nursling's behavior.

Although the majority of human infants are breast-fed for the first few months of life, there is a paucity of information regarding the sensory qualities of human milk and how these qualities are affected by maternal diet. The present study investigated the effects of garlic ingestion by the mother on the odor of her breast milk and the suckling behavior of her infant. Evaluation of the milk samples by a sensory panel revealed garlic ingestion significantly and consistently increased the perceived intensity of the milk odor; this increase in odor intensity was not apparent 1 hour after ingestion, peaked in strength 2 hours after ingestion, and decreased thereafter. That the nursling detected these changes in mother's milk is suggested by the finding that infants were attached to the breast for longer periods of time and sucked more when the milk smelled like garlic. There was a tendency for infants to ingest more milk as well; the lack of a significant effect may be due to the inherent limitations on the total amount of milk available to the infant.

Adult↗
PubMed1990

A new method for delivering a taste without fluids to preterm and term infants.

A new method for administering a taste to preterm and term infants has been developed that does not necessitate the delivery of rapid solutions. Sucrose, a sugar that in solution was shown to potentiate sucking behavior, was embedded in gelatin-based nipples that continuously release sweet taste when mouthed or sucked. The gelatin nipples and comparable latex nipples were adapted to measure sucking behavior and were tested in a within-subject design. The gelatin nipples potentiated sucking in preterm and term infants by increasing the frequency and strength of the responses. Few sucking measures varied significantly for preterm and term infants. Those that did vary might be attributable to differences in physical stamina, rather than to orosensory or hedonic factors. It was concluded that the flavored gelatin nipple provides an effective method for studying taste in infants and offers the possibility of routine chemosensory stimulation for research and clinical applications.

Discrimination Learning↗
PubMed1990

Chemosensory identity and the Y chromosome.

Genes in the extended major histocompatibility complex (MHC) of the mouse (H-2: Qa:T1a) impart to each mouse an odor that reflects its genetic constitution at this region of chromosome 17. Sensory recognition of these differential odors influences reproductive behavior and evokes neuroendocrine responses critical to the maintenance of pregnancy. To determine whether other parts of the mouse genome contribute to individual odor, and so may similarly exert a selective force on loci other than the MHC, mice differing genetically only in their X and/or Y chromosomes were tested for individuality of scent in the Y-maze system previously employed to investigate MHC-related scent distinctions. It was found that the X and Y chromosomes each confer individuality of scent related to genotype, but differences at the H-2 locus are considerably more salient. Nevertheless, chemosensory cues controlled by differences on the Y chromosome could play a role in individual recognition, mate selection, aggressive interactions, and perhaps other aspects of mouse chemosensory behavior.

Animal Communication↗
PubMed1990

Odor types determined by the major histocompatibility complex in germfree mice.

The major histocompatibility complex (MHC) is the prime but not exclusive determinant of genetically specific constitutive body odors, termed odor types, represented strongly in urine of the mouse. Perception of MHC-determined odor types influences reproductive behavior in the contexts of mate choice and maintenance of early pregnancy, tending to favor the propagation of one MHC type over another. How MHC genotype determines MHC odor type is unknown. One possible explanation is that differential odorants are generated by populations of commensal microorganisms whose composition is somehow geared to MHC diversity. This hypothesis was tested in the Y-maze system in which mice are trained to distinguish the urinary odors of MHC-congenic mice. First, it was shown that mice could readily be trained to distinguish the urines of germfree MHC-congenic mice. Second, it was shown that mice trained to distinguish the urines of conventionally maintained MHC-congenic mice could as readily distinguish the urines of germfree MHC-congenic mice. These results imply that MHC-determined odor types do not depend on odorants generated by microorganisms.

Animals↗
PubMed1990

Experimental sodium depletion and salt taste in normal human volunteers.

To examine the sensory effects of extreme sodium depletion in humans, 10 normal volunteers were fed a very-low-sodium diet and were treated with diuretics for 10 d. Urine samples were collected and blood was drawn for hormone analyses. Taste tests included threshold and intensity judgments of salt (NaCl) and sucrose and preferences for salt and sucrose in foods. Subjects also rated the pleasantness of 29 foods listed on a questionnaire. Substantial sodium depletion was induced in all subjects. Salt thresholds decreased in a majority of the subjects whereas preference judgments for salt in foods tended to be greater during the depletion period. The changes in pleasantness of the 29 foods revealed that saltier foods were substantially more attractive during the depletion period than during the pre- and postdepletion periods. These data indicate that experimental sodium depletion in humans is followed by moderate sensory changes and an increased preference for salty foods.

Adult↗
PubMed1989

Changes in sensitivity to the odor of androstenone during adolescence.

While it has been reported that most, if not all, very young children are able to detect the odor of 5 alpha-androst-16-en-3-one (androstenone), approximately 40-50% of human adults cannot detect its odor. The present study focused on changes in sensitivity to androstenone during adolescence, which may account for this discrepancy. Sensitivity to androstenone was determined in 247 subjects aged 6 to 50. There was a significant increase in the number of males anosmic to androstenone between 9-14 and 15-20 years of age, and a significant increase in threshold with age among males able to detect the odor. We infer that a smaller percentage of females than males becomes anosmic to the odor of androstenone during development, and those able to detect it apparently show a decrease in threshold with age. No age-related changes were observed in tests of pyridine or d,l-beta-phenylethylmethylethylcarbinol (PEMEC).

Adolescent↗
PubMed1989

Sex, handedness and side of nose modulate human odor perception.

Multidimensional scaling was used to analyze odor similarity judgments obtained by monorhinic (single nostril) stimulation from normal subjects (N = 52), equally partitioned by sex and handedness. Neither sex nor handedness nor side of nose appeared to alter the position of stimuli on a two-dimensional map of odor similarity. However, women produced significantly more consistent maps than men. This result was not due to differential utilization of axes in the multidimensional perceptual space, nor to differences in verbal labeling. Left versus right nostril asymmetries were significantly greater in dextrals.

Adult↗
PubMed1989

Ability to perceive androstenone can be acquired by ostensibly anosmic people.

Nearly half the adult human population does not perceive an odor when sniffing androstenone (5 alpha-androst-16-en-3-one), a volatile steroid found in human perspiration, boar saliva, some pork products (e.g., bacon), truffles, and celery. This variation in ability to perceive androstenone has a significant heritable component, suggesting that androstenone insensitivity is in part determined genetically. We now report that the ability to perceive androstenone was induced in 10 of 20 initially insensitive subjects who were systematically exposed to androstenone. Since olfactory neurons of the olfactory epithelium undergo periodic replacement from differentiating basal cells, and assuming the induction of sensitivity to be peripheral, we propose that a portion of the apparently anosmic human population does in fact possess olfactory neurons with specific receptors for androstenone. Such neurons may undergo clonal expansion, or selection of lineages with more receptors or receptors of higher affinity, in response to androstenone stimulation, much in the manner of lymphocytes responding to antigenic stimulation, thus raising odor stimulation to the level of conscious perception. As a guide to further study of the genetics and mechanism of variation of androstenone perception, we provisionally envisage three categories of human subjects, the truly anosmic, the inducible, and those subjects who either are constitutionally sensitive or have already experienced incidental induction.

Androstenes↗
PubMed1989

Sex-chromosomal odor types influence the maintenance of early pregnancy in mice.

Genetically specified body odors are termed odor types. We showed previously that both the X chromosome and the Y chromosome of the mouse determine differential odor types demonstrable by the behavior of trained mice in the conventional Y-maze test system extensively used in the definition of odor types specified by the major histocompatibility complex (MHC). In the present studies we aimed to ascertain whether perception of X chromosomal and Y chromosomal odor types, like the perception of MHC odor types, exerts a spontaneous influence on reproduction. By making use of reciprocal F1 hybrid males and males of the congenic B6.YAKR strain, males differing solely in their X chromosomes, their Y chromosomes, or both were tested in the conventional pregnancy-block system in which isolated females in early pregnancy are known to be subject to a heightened incidence of failed pregnancy when confronted with the scent of a male whose MHC type differs from that of the missing stud male. As previously established for MHC disparity, perception of X chromosomal disparity or of Y chromosomal disparity between stud and secondary males caused a highly significant rise in the incidence of terminated pregnancy. Thus perception of differential odor types other than those specified by the MHC may also be concerned in aspects of selective reproduction.

Animals↗