Developmental Biology Commons^™

The Effects Of Nesting Environment On Neonatal Hypoxic-Ischemic Injury, Laura Grace Rollins

Graduate Masters Theses

Term neonates with hypoxic-ischemic (HI) injury are at risk for devastating neurological sequelae. The objective of this study is to determine if altering the early environment for maternal care-taking impacts the immediate and long-term sequelae of HI offspring. The Rice-Vannucci model was used to induce HI in postnatal day (PND) 7 Long-Evans pups. Litters were assigned to a closed nest (CN) or normal standard housing (SH) condition. Neurobehavioral development, cognitive ability, and stress response were assessed to establish any benefits of the CN condition. Finally, postmortem brain tissue was analyzed for morphometric markers of injury.

Prenatal Development: Annotated Bibliography, Victoria J. Molfese, Amanda Prokasky, Kathleen Moritz Rudasill, Ibrahim H. Acar, Xiaoqing Tu, Kate Sirota, Brian Keiser

Department of Child, Youth, and Family Studies: Faculty Publications

For decades, researchers have investigated how events in the prenatal period impact women and their infants. These studies, particularly by researchers in the medical, neuroscience, and behavioral science fields, led to discoveries of important information regarding the prenatal events that were strongly associated with mortality (or death) and morbidity (or incidences of injury, pathology and abnormalities/anomalies, and neurobehavioral sequelae) in the neonatal and infancy periods. Among the many common findings from early research studies, two are particularly noteworthy. First, maternal and fetal risk conditions arising in the prenatal period do not do so in isolation. Sameroff and Chandler characterized this …

Ontogeny Of Venom Use And Venom Composition In The Western Widow Spider Latrodectus Hesperus, David Roger Nelsen

Loma Linda University Electronic Theses, Dissertations & Projects

I investigated the behavioral ecology of venom and venom use by the western widow spider (Latrodectus hesperus), emphasizing the role of ontogeny. In an introductory paper, I reviewed existing definitions of venom and poison, and refined these by adding a third category of toxic biological secretions: toxungen. These three can be distinguished by mode of toxin delivery and presence of a wound. In the first of four empirical studies, I investigated venom use by adult females in the context of threat assessment. A single brief poke at the lowest threat level elicited primarily avoidance responses ("move" and "retract"), repeated prodding …

Rapid Range Expansion In The Great Plains Narrow-Mouthed Toad (Gastrophryne Olivacea) And A Revised Taxonomy For North American Microhylids, Jeffrey W. Streicher, Christian L. Cox, Jonathan A. Campbell, Eric N. Smith, Rafael O. De Sá

Biology Faculty Publications

We investigated genetic variation within the Great Plains narrow-mouthed toad, Gastrophryne olivacea, across its geographic range in the United States and Mexico. An analysis of mitochondrial DNA (mtDNA) from 105 frogs revealed remarkably low levels of genetic diversity in individuals inhabiting the central United States and northern Mexico. We found that this widespread matrilineal lineage is divergent (ca. 2% in mtDNA) from haplotypes that originate from the western United States and western coast of Mexico. Using a dataset that included all five species of Gastrophryne and both species of the closely related genus Hypopachus, we investigated the phylogenetic …

Physician Perceptions Of Risk Regarding Mood Disorders And Pharmacological Management During Pregnancy: What Is Current Practice?, Laura G. Hendon

Dissertations and Theses (Open Access)

Mood disorders are the most common form of mental illness and one of the leading causes of morbidity worldwide.  Major depressive disorder and bipolar disorder have a lifetime prevalence of 16.2% and 4.4%, respectively.  Women comprise a substantial proportion of this population, and an estimated 500,000 pregnancies each year involve women with a psychiatric condition.  Management with psychotropic medications is considered standard of care for most patients with mood disorders.  However, many of these medications are known human teratogens.  Because pregnant women with mood disorders face a high risk of relapse if unmanaged, the obstetrician faces a unique challenge in …

Individuals And Populations: How Biology's Theory And Data Have Interfered With The Integration Of Development And Evolution, David S. Moore

Pitzer Faculty Publications and Research

Research programs in quantitative behavior genetics and evolutionary psychology have contributed to the widespread belief that some psychological characteristics can be “inherited” via genetic mechanisms. In fact, molecular and developmental biologists have concluded that while genetic factors contribute to the development of all of our traits, non-genetic factors always do too, and in ways that make them no less important than genetic factors. This insight demands a reworking of the Modern Evolutionary Synthesis, a theory that defined evolution as a process involving changes in the frequencies of genes in populations, and that envisioned no role for experiential factors now known …

Sexually Dimorphic Effects Of Prenatal Stress On Cognition, Hormonal Responses, And Central Neurotransmitters, Rachel E. Bowman, Neil J. Maclusky, Yessenia Sarmiento, Maya Frankfurt, Marisa Gordon, Victoria N. Luine

Psychology Faculty Publications

Exposure to stress during gestation results in physiological and behavioral alterations that persist into adulthood. This study examined the effects of prenatal stress on the postnatal expression of sexually differentiated cognitive, hormonal, and neurochemical profiles in male and female rats. Pregnant dams were subjected to restraint stress three times daily for 45 min during d 14-21 of pregnancy. The offspring of control and prenatally stressed dams were tested for anxiety-related and cognitive behaviors, stress and gonadal steroid hormone levels, as well as monoamines and metabolite levels in selected brain regions. Postnatal testosterone levels (measured at 1 and 5 d) did …

Within-Litter Birth Weight Variation In The Domestic Pig And Its Relation To Pre-Weaning Survival, Weight Gain, And Variation In Weaning Weights, Barry N. Milligan, David Fraser, Donald L. Kramer

Ontogeny Collection

To determine the relationship between within-litter birth weight variation and pre-weaning survival and weight gain, and to provide practical guidance on fostering low-birth-weight piglets, we analyzed piglet survival and weight gain in litters of piglets from 52 sows followed through eight consecutive parities. Litters with high variation in birth weight had more deaths, especially if the litter’s mean birth weight was low. High variation in birth weight was also associated with high variation in weaning weight, but was not significantly related to mean weaning weight. Piglets with birth weights well below the range of most of the litter (‘low-birth-weight piglets’) …

The Effect Of Littermate Weight On Survival, Weight Gain, And Suckling Behavior Of Low-Birth-Weight Piglets In Cross-Fostered Litters, Barry N. Milligan, David Fraser, Donald L. Kramer

Ontogeny Collection

Objective: To determine whether low-birth-weight piglets show better survival, weight gain, and suckling behavior when grouped with other small piglets by cross-fostering.

Methods: We manipulated the number and size of foster littermates for low-birth-weight piglets in 31 small (eight or nine piglets) and 22 large (11 or 12 piglets) litters. Experimental litters were composed of four to six piglets of lowest birth weight and either four to six slightly heavier or four to six much heavier piglets from two combined litters.

Results: Low-birth-weight piglets raised with much heavier littermates had somewhat lower survival rates, but showed no tendency towards lower …

Vocal Response Of Piglets To Weaning: Effect Of Piglet Age, Daniel M. Weary, David Fraser

Ontogeny Collection

Piglets vocalize a great deal during the first few days after weaning. The aim of this experiment was to determine if the calls given by piglets vary in response to one factor thought to influence post-weaning adaptation: weaning age. In 22 litters, each containing a minimum of 9 piglets, 3 piglets were weaned under identical conditions at 3, 4 and 5 weeks of age. Vocalizations and weight gain were monitored for the week after weaning. The number of calls produced by piglets of all three ages declined from an average of 8.2 calls/min per piglet on the day of weaning …

Variation In Piglet Weights: Weight Gains In The First Days After Birth And Their Relationship With Later Performance, B. K. Thompson, D. Fraser

Ontogeny Collection

Piglets from 42 litters of Yorkshire sows were weighed 0, 1, 2, 3, 4, 5, 7, 10, and 14 d after farrowing in order to explore the highly variable weight gains during the first 2 wk after birth. All litters were adjusted to 10-12 piglets by fostering. Litters differed greatly in average gain per piglet during the first 3 d after farrowing, with litter means ranging from 5 to 227 g d‒1 per piglet for the 3-d period. Gains during days 0-3 tended to be somewhat lower if the sow had a high body temperature during these days, but the …

Use Of Water By Piglets In The First Days After Birth, David Fraser, P. A. Phillips, B. K. Thompson, W. B. Peeters

Ontogeny Collection

Use of drinking water was determined for 51 litters of piglets by weighing and refilling a water dispenser each day for the first 4 d after farrowing. Measures of spillage, evaporation, and piglet drinking behavior indicated that most disappearance of water represented actual drinking by the piglets. Water use varied greatly among litters with an average of 46 g d^‒1 per piglet over the 4 d, and a range of negligible use to about 200 g d^‒1. Water use, especially on day 2, was correlated negatively with the average weight gain of the litter during the first …

Variation In Piglet Weights: Development Of Within-Litter Variation Over A 5-Week Lactation And Effect Of Farrowing Crate Design, B. K. Thompson, D. Fraser

Ontogeny Collection

Piglets from 51 litters were weighed weekly over a 5-wk lactation in an experiment that studied the effects of farrowing crate design and other factors on variation in piglet weight. Of two farrowing crates used, one had low horizontal bars that tended to impede access to the upper row of teats, while the other had angled vertical bars which permitted freer access. Fourteen-day weights were more uniform in the vertical-bar crates than in the horizontal-bar crates (P < 0.025), but the difference waned by day 35 (P > 0.05). There were no significant differences in mean body weight owing to crate type (P < 0.05) for any of the weekly measurements but, by day 14, there was a significant linear trend (P < 0.05) at decreasing main body weight with increasing litter size. The interaction between crate type and litter size was significant at the later ages (P < 0.01 at day 35) because the linear trend was more pronounced for horizontal-bar crates than for vertical. Litters differed greatly in the uniformity of their body weights. Much of the variation became established in the first and, to a lesser extent, the second week after birth. In those weeks, weight gains were highly variable and were not closely related to weight at the beginning of the week. Thereafter, the established differences tended to be perpetuated to 35 d, because weight gains were largely proportional to body weight. Within-litter competition appeared to influence weight gain considerably.

Variation In Piglet Weights: Relationship To Suckling Behavior, Parity Number And Farrowing Crate Design, David Fraser, B. K. Thompson

Ontogeny Collection

Suckling behavior and weight change of piglets were studied during the first 2 wk after birth. Thirty-six litters comprised a balanced comparison of parity number (first or second), litter size (8, 10 or 12), and two farrowing crate designs, one of which had a low horizontal bar that tended to impede the piglets' access to the udder. Piglets showed the expected preference for the anterior teats although the preference was more apparent in the second parity than in the first. Teat fidelity was most pronounced at the two ends of the udder; piglets occupying the middle positions did more fighting …