Biomedical subjects

J A Mennella

Publications and source records attributed to J A Mennella.

8 recordsLinked to original sources

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

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↗

PubMed1989

Pheromonal emission by pregnant rats protects against infanticide by nulliparous conspecifics.

The present studies of experiments focuses on infanticide in the nulliparous rat and asks two questions. First, what do infanticidal nulliparae gain from killing unrelated young? And second, does the recently parturient female have an effective strategy to counter female infanticide? With regard to the first question, we show two benefits from killing unrelated young, namely, that the killer utilizes the young as a food resource and that she occupies the nest site of the mother whose young she has destroyed. With regard to the second question, we show that an extended period of cohabitation with a pregnant female reduces the incidence of infanticidal behavior in nulliparae. Additionally, we demonstrate that the mother emits a pheromone during pregnancy which in itself reduces the incidence of infanticide and, in fact, often makes potentially infanticidal females maternal. The possible endocrine basis of this induced maternal behavior is discussed.

Animals↗

PubMed1988

Infanticide in the male rat: the role of the vomeronasal organ.

The present study constitutes the first demonstration that vomeronasal chemoreception plays a role in the response of the virgin male rat to conspecific newborn. Specifically, it shows that virgin males, after removal of the vomeronasal organ, exhibit a decrease in the incidence of infanticidal behavior. This finding is discussed in terms of how responsiveness to young can be affected by changes in the accessory olfactory system.

Aggression↗

PubMed1988

Infanticide in rats: male strategy and female counter-strategy.

The present series of experiments addresses the question of whether mating governs infanticide in the male rat and, in addition, asks whether the female rat has available an effective counter-strategy to male infanticide. With regard to the first question, we found that mating provides a safeguard against the killing of own young. That is, mating induces a general inhibition of infanticide coincident with the birth of the male's young and a recrudescence of infanticide synchronized with their weaning. The particular gain realized in killing alien young depends on the age of young and consequently on whether the mother had reached postpartum estrus. We also found that the pregnant female has an effective strategy to counter male infanticide which she employs before the young are born. The data show that this counter-strategy involves the synthesis of a chemosignal of low volatility emitted during pregnancy. The possible role of the male's vomeronasal system in the reception of this chemosignal is discussed.

Aggression↗

PubMed1987

Hypothalamic temperature and deep body temperature during copulation in the male rat.

The medial preoptic area (MPOA) of the hypothalamus is involved in both the expression of male sexual behavior and the regulation of physiological temperature. This duality of function led us to ask whether arousal, intromission, and ejaculation are accompanied by a distinctive temperature profile. Using telemetric thermosensors, we monitored MPOA temperature and deep body temperature during copulation in the male rat. Changes in MPOA temperature were highly uniform, more so than changes in body temperature. The MPOA heated prior to ejaculation, cooled rapidly following ejaculation and then began to heat again coincident with the termination of the post-ejaculatory refractory period. These changes could not be related to variations in general activity. The most striking change in MPOA temperature, rapid cooling following ejaculation, was explained in terms of certain behaviorally-induced hemodynamic events.

Animals↗

PubMed1986

A simple operation method on removal of the vomeronasal organ of the rat.

The vomeronasal organ (VNO) of the rat was removed completely using the following operation procedure. The mouth of the anesthetized rat was opened. A midline incision was made in the plate of the upper jaw, the tissue was retracted and a hole was drilled at both the anterior and posterior points of attachment of the VNO. The location of these holes allowed removal of the bone to which the VNO is attached together with the VNO itself.

Animals↗