Despite a rich fossil record and much attention from paleontologists, the phylogeny of mammalian order Perissodactyla (including extant horses, rhinoceroses, and tapirs) is poorly understood. There are at present no well-supported phylogenetic hypotheses of the interrelationships of perissodactyls, nor has the position of this order among other eutherian orders been established. The main hindrance to this understanding is a lack of thorough and rigorous analysis of characters and taxa. This study attempts to overcome this problem by analyzing characters from all aspects of the skeleton in a broad diversity of taxa for one major perissodactyl lineage, the Tapiromorpha. Studies of interordinal and intraordinal relationships of the Perissodactyla have previously been effectively incompatible, because these two types of studies utilized different types of characters. Interordinal studies focused on cranial and postcranial characters, whereas intraordinal studies relied heavily on tooth morphology. This study focuses on cranial and postcranial osteology. The cranial and postcranial skeleton of a broad range of tapiromorphs is described. These descriptions have two purposes: (1) to identify potentially useful characters for use in a phylogenetic analysis of tapiromorphs; and (2) to provide a reference on tapiromorph osteology that will facilitate the inference of primitive tapiromorph character states for higher-level analyses. Putative tapiromorphs include "tapiroids," rhinocerotoids, and chalicotherioids. Numerous representatives of these groups are compared with other perissodactyls (equoids and brontotheres) and eutherians thought to be closely related to perissodactyls. Cranial and postcranial characters drawn from the afore-mentioned descriptions are combined with selected dental characters in a phylogenetic analysis of tapiromorph genera. For the sake of clarity, higher-level taxonomic groups are defined a priori. The results of the phylogenetic analysis demonstrate that there is no unequivocal evidence for including chalicotherioids or the traditional primitive "tapiroid" Homogala in the Tapiromorpha (as defined here). The analysis supports the close relationship between tapirs and rhinoceroses relative to horses, as well as clades that fulfill the definitions of Tapiroidea and Rhinocerotoidea. The results of the phylogenetic analysis provide the basis for a revised classification of the Tapiromorpha.

Nutrition greatly affects the reproductive success in many insects. Also, previous studies have shown this nutrition-reproduction connection is mediated via endocrine control. In Phormia regina, a proteinaceous meal is essential for egg maturation. Recent discovery of a midgut hormone, from liver-fed P. regina, established a link between feeding and endocrine function which leads to oogenesis. This midgut hormone is the first such insect gut hormone governing oogenesis. Whether or not this hormone is released into the hemolymph, however, is not determined. To demonstrate the existence of the midgut hormone in the hemolymph, hemolymph was partially purified and its oogenesis-stimulating effect tested. A gonadotropic effect was observed in the hemolymph extracts prepared from 5 and 6h post-liver-fed females. The midgut hormone appears to circulate in the hemolymph to reach its target, presumably the brain neurosecretory cells. Injection of partially purified midgut hormone caused a significant volume increase and changes in the distribution of stainable materials of the type-A brain median neurosecretory cells (MNCs). It is conceivable that these cellular changes reflect the synthesis/release of neurohormones by the type-A MNCs. Thus, results suggested that midgut hormone is hemolymph-borne and has a cerebrotropic function. The possible role of the brain after being stimulated by midgut hormone was investigated. In vitro studies showed that the brain releases, at 8h after a protein meal, a factor(s) with a strong allatotropic effect (i.e., causing the corpus allatum (CA) to produce 6.9 times more juvenile hormones (JHs) than the control CA). The characteristics of this allatotropic factor(s) were estimated with different experiments. First, Manduca sexta allatotropin (Mas-AT)-immunopositive substances were observed in the lateral neurosecretory cells (LNCs) and the neurosecretory cells located between the pars intercerebralis and oesophagus foramen. Second, synthetic Mas-AT stimulated JH biosynthesis by the fly's CA (2.64-fold activation when stimulated with 20 pmol per test). Third, when brain-released factor(s) was neutralized with anti-Mas-AT antiserum both in vivo and in vitro, the CA still synthesized a considerable quantity of JH. This result suggested that there may be additional non-Mas-AT allatotropic agent in P. regina.

The fact that physical performance deteriorates concomitantly with the process of senescence is well-documented. However, little is actually known regarding the control mechanisms which induce the physiological dysfunction associated with age. The purpose of this investigation was to evaluate the effect of age on neuromotor coordination mechanisms and fractionated reaction time parameters during the execution of ballistic forearm flexion and extension, maximum voluntary isometric forearm flexion and extension strength and limb volume. A total of 48 male subjects in three age groups were studied (16 in each group): (1) 30-40 years old, (2) 50-60 years old and (3) 61-70 years old. On each of four test days each of the following criterion measures were recorded: (1) two slow and two fast maximum voluntary isometric contractions of the flexors of one arm and the extensors of the other arm, (2) twenty simple reaction time trials of the flexors of one arm and the extensors of the other arm, (3) twenty simple resisted reaction time trials of the flexors of one arm and the extensors of the other and (4) twenty trials of speed of movement at two inertial loads for the flexors of one arm and the extensors of the other arm. A repeated measures analysis of variance was employed to determine which data was the most stable. The analysis that there were few significant differences between the trials recorded on day 1 and day 2, indicating that performance had stabilized. Intraclass correlation analysis showed that the criterion measures were reliable. Age group comparison revealed significant differences between the groups for: (1) maximum voluntary isometric strength, (2) maximum displacement, (3) agonist silent period, (4) accuracy, (5) resisted motor time and (6) resisted total reaction time. A non-significant age-related trend for the following parameters to be adversely affected with age was noted: (1) movement time, (2) agonist first burst motor time, (3) antagonist first burst motor time, (4) antagonist second burst duration, (5) agonist first burst integrated electromyographic slope, (6) antagonist second burst time to peak activity, (7) time to maximum acceleration, (8) agonist first burst peak amplitude, (9) antagonist second burst peak amplitude, and (10) acceleration as a percentage of movement time.

Exercise-induced muscle damage may alter the availability of glutamine for cells of the immune system following strenuous exercise. However, little is known about the effects of exercise-induced muscle damage on the immune system. Elevated serum CK activity, an indirect marker of muscle damage, was used as a post-exercise criterion to place subjects who performed the same exercise into High and Low CK groups. The purpose of this investigation was to determine whether (1) the response of plasma glutamine concentration; and (2) cellular components of the peripheral blood, particularly leukocyte numbers and subset proportions, responded similarly to high force eccentric in High and Low CK groups. Twelve female subjects performed high-force eccentric exercise using one arm and one leg, respectively. Blood samples were collected 1 d and 0 h pre-exercise, 0 and 2 h, 1, 2, 3, 5, 7, and 9 d post-exercise and analyzed for serum CK activity, whole blood glutamine concentration, complete blood count, and lymphocyte subsets consisting of T, CD4+, CD8+, B, NK, and IL-2 receptor positive (IL-2R+) lymphocytes. Seven subjects were placed in the High CK group and 5 in the Low CK group. Differences between High and Low CK groups, identified by comparing the positive and negative integrated areas of deviation from baseline, respectively, were not apparent. For all subjects combined into a single group, there was a 13% increase in granulocytes 0 and 2 h post-exercise, 24 and 29% increases in NK cell concentration and proportion of lymphocytes immediately post-exercise, a delayed increase in NK cells 3 and 9 d post-exercise, and 17 to 22% decreases in CD8+ lymphocytes 2, 5, and 9 d post-exercise (p $<$ 0.05 for all). A significant decrease in blood glutamine concentration (p $<$ 0.05) was measured 3 d post-exercise. These changes were either the result of changes at the level of the muscle induced by the exercise, but independent of factors contributing to CK efflux, or the result of as yet unidentified systemic signals initiated by the performance of the exercise.

The newly resurgent field of evolutionary developmental biology integrates the study of evolutionarily important anatomical changes and developmental biology to describe the genetic and developmental changes that have led to anatomical changes. In this dissertation I describe candidate developmental mechanisms in the context of axial elongation and pectoral fin musculature evolution in fishes. Both axial elongation and increase in pectoral fin muscle subdivisions have important ecological correlates. Elongate fishes tend to be found in highly structured environments and fishes with an increased number of fin muscles tend to use fin-based locomotion to swim. Both of these morphologies have evolved multiple times within the ray-finned fish radiation. In Chapter 1 I focus on a specific predator avoidance behavior that is only seen in elongate fishes. Deeper-bodied fish tend to perform a unilateral bend of the body and swim away whereas elongate fish, when startled, bend bilaterally and hide. Although all elongate fishes perform head retraction, their specific anatomy indicates multiple explanations for how elongation occurs. In Chapter 2, I describe changes in the vertebral column in lineages of actinopterygian fishes that have elongate members. Elongation occurs through three different mechanisms: addition of abdominal vertebrae, addition of caudal vertebrae, and lengthening of all the vertebral cents. This study suggests that the number of abdominal vertebrae, number of caudal vertebrae, and length of the vertebral cents are controlled by separate developmental modules. Fin-based locomotion has evolved multiple times independently within actinopterygian fishes and is correlated with a modification of the pectoral fin musculature. In order to increase the understanding of fin muscle development, in Chapter 3 I describe the wildtype anatomy and embryology of the pectoral fin musculature in the zebrafish, Danio rerio. Zebrafish have six muscles in the pectoral fin. Early in development, the fin musculature consists of two muscle masses, one on each side of the fin. The arrector ventralis is the first muscle to individuate from the initial abductor muscle mass, and the adult musculature is present by 3 weeks postfertilization. This study provides a basic understanding of the embryology of the fin muscles and will provide a baseline for examining mutant fin muscle morphologies in zebrafish and diverse fin muscle morphologies in other species.

The studies included in this dissertation address the role of blood flow and cellular oxygenation in skeletal muscle fatigue, with an underlying interest in age-related differences in muscle fatigue. In the first study, I found that blood flow immediately post-contraction was tightly coupled to contraction intensity throughout an incremental isometric dorsiflexor contraction protocol in healthy young men. This relationship was independent of fatigue, and the onset of fatigue occurred before any reduction or plateau in blood flow. These data suggest that fatigue during intermittent incremental contractions does not result from a blood flow limitation. The second study used magnetic resonance spectroscopy of deoxymyoglobin to examine the role of intracellular oxygenation in muscle fatigue during slow and rapid incremental contractions in healthy young men and women. Data from this study showed that the rate of deoxygenation relative to force during contractions was predictive of fatigue, and this was true for slow and rapid contractions. Further, intracellular oxygenation was lower, and fatigue greater, during more metabolically demanding rapid contractions. These data support a role for intracellular oxygenation in the development of fatigue. The final study investigated whether differences in intracellular oxygenation could explain age-related differences in muscle fatigue. During slow contractions, intracellular oxygenation was higher, but fatigue lower, in older compared to young subjects. After matching a subset of subjects by muscle strength, age-group differences in oxygenation were eliminated, but fatigue was still less in older subjects, suggesting that while differences in oxygenation exist between young and older subjects, they cannot explain the age-group differences in fatigue. This conclusion was supported by a similar oxygenation, but greater fatigue, in young compared to older subjects during rapid contractions. Based on these findings, intracellular oxygenation does not appear to play a role in the age-related differences in fatigue observed in this and other studies. Together, data from this dissertation suggest that intracellular oxygenation plays a role in the development of muscle fatigue, despite the ability of blood flow to match contraction intensity. Differences in oxygenation, however, cannot explain age-related differences in muscle fatigue.

The peripubertal period is a period during which significant brain re-organization occurs, and during which changes in the neuroendocrine milieu normally lead to the onset of fertility. Shipping female mice during the peripubertal period causes a long-lasting behavioral defeminization of feminine sexual behavior. Because shipping is a stressor, it was suggested that peripubertal stress exposure might interfere with the regulation of feminine sexual behaviors in adult female mice. As a result, the goal of this research was to examine the effects of peripubertal stress exposure on neuroendocrine regulation of the hypothalamo-pituitary-gonadal (HPG) and the hypothalamo-pituitary-adrenal (HPA) axis. However, although peripubertally exposing female mice to shipment stress caused a significant decrease in sexual receptivity, peripubertal exposure to restraint stress, food deprivation, social stress and instability, or multiple stressors (heat, light, and restraint) did not decrease sexual receptivity during adulthood. Only exposure to a high dose of bacterial endotoxin during the peripubertal period duplicated the defeminizing effect of shipping during the peripubertal period on adult mouse feminine sexual behavior. Interestingly, significant long-term effects of peripubertal stress exposure were also observed in the regulation of the HPA axis, where exposure to peripubertal shipping and LPS led to blunted stress-induced corticosterone responses in adult female mice. Peripubertal exposure to shipping and LPS had long-lasting effects on steroid receptor expression in brain areas relevant to female reproduction. Nevertheless, peripubertal exposure to LPS did not interfere with the ability of estradiol to induce the release of LH. Moreover, although peripubertal exposure to shipping decreased masculine sexual behavior in male, but not female, mice, peripubertal exposure to LPS was without effect on masculine sexual behavior. These results suggest that exposure to some, but not all, peripubertal stressors can induce long-lasting changes in reproductive behaviors, as well as changes in the expression of sex steroid receptors known to regulate these behaviors.

As an excellent organism for genetic study and with the many useful genetic manipulation tools developed in the past two decades, Drosophila melanogaster is an important model organism that has been utilized to understand the genetic regulation of various developmental processes. Here, we focus on the development of the Drosophila CNS midline cells to pursue a long term goal to understand (1) the regulation of programmed cell death during nervous system development and (2) the interaction between nervous system and the mesoderm structures during early embryonic development. Programmed cell death is an essential part of the development of the nervous system for vertebrate and invertebrate animals (reviewed by Oppenheim 1991). In the Drosophila CNS midline, about 70% of the glia cells die during a critical period. We found that the elimination of unwanted midline cells during embryonic nervous system development is a very well coordinated process, which ensures that specific number of midline glia survive. The others are relocated and executed by proteolytic cascade, followed by engulfment and further degradation by macrophages. We observed that three cell death regulatory genes (rpr, hid and grim) in the 75C1,2 region of the 3rd chromosome are all expressed in midline cells that are chosen to be executed. Using several mutants and genetic deficiencies, we found that in order for the appropriate number of midline cells to be eliminated, the functions of multiple genes in the 75C1,2 region are required. To further understand this cell death process, we targeted the expression of rpr and/or hid to midline cells. We found that the two genes show synergism in inducing ectopic cell death, further suggesting that they may functionally interact to regulate the proper cell death pattern. Inside the embryo, the development of the nervous system is not a isolated process. The developing nerve cells interact with the mesoderm during early embryonic development. We found that the CNS midline cells are required for the differentiation of a specific group of mesoderm cells, the dorsal median cell. The well conserved epidermal growth factor (EGF) signaling pathway is at least partially responsible for this CNS midline regulation of mesoderm cell development. In addition, we found that the proper anterior/posterior location of the dorsal median cells depends on the function of wingless or patched segmental polarity gene, and that these two genes might act through regulating the spatial differentiation of the CNS midline cells.

The purpose of this study was to determine if administering two painful stimuli used to assess motor responses in patients with brain injury, nail bed compression (NBC) and supraorbital pressure (SOP), had an effect on intracranial pressure (ICP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP), heart rate (HR), and motor responses, in unconscious patients. Thirteen unconscious adult male and female subjects with brain injury were enrolled in the study. All subjects had normal ICP and CPP, and were hemodynamically stable. After collection of baseline values of the dependent variables, NBC and SOP were delivered on both sides of the body while ICP, MAP, CPP and HR were recorded from the bedside monitor. Subjects were recorded on video tape for motor responses to NBC and SOP and later given a motor score on the Glasgow Coma Scale. Pressures used to administer NBC and SOP were measured in psi by devices constructed for purposes of this study. Data were analyzed using MANOVA statistical procedures to detect differences within subjects on all physiological values from baseline. Findings from this study were that NBC and SOP administered on both sides of the body resulted in statistically significant increases in ICP, MAP, CPP, and HR from baseline for a brief, yet unsustained time period (p = $<$0.05). The ICP had returned to baseline in 30 seconds, the MAP and CPP within four minutes, and HR by the second minute after administration of NBC and SOP. ANOVA statistical procedure was used to detect differences in motor scores when NBC and SOP were given. There were no statistical differences between motor scores on the GCS with NBC or SOP. The mean pressures that were measured on NBC and SOP were 77.11 $\pm$ 30.98 and 86.1 $\pm$ 8.54 psi, respectively. These data suggest that NBC and SOP do have an effect on physiological indices of cerebral perfusion by an increasing ICP, MAP, CPP, and HR for a brief period of time but return to baseline quickly. Therefore, administering painful stimuli to evaluate motor responses in unconscious patients who have normal ICP and CPP is probably safe. Also, the data suggest that NBC and SOP produce similar motor responses and could both be used to assess unconscious patients.

In this study nuclear and ooplasmic maturation of prepuberal calf oocytes was evaluated to determine a possible cause for their low developmental competency. Calf oocytes resumed meiosis and arrested at the metaphase II stage at rates similar to that of adult animals; however, zygotes derived from calf oocytes cleaved and developed at significantly lower rates. Ooplasmic maturation was assessed during oocyte maturation and fertilization. Transmission electron microscopy revealed that a majority of calf oocytes exhibited some delay in organelle migration and redistribution following maturation. Immunofluorescence microscopy showed that following in vitro fertilization, a higher percentage of calf oocytes had abnormal chromatin and microtubule configurations than those of adult cattle. Delayed formation of sperm aster and asynchronous pronuclear formation characterized these anomalies. Microfluorometry was used to characterize the Ca$\sp{2+}$ responses of calf oocytes to the addition of agonists. The addition of thimerosal demonstrated the presence of Ca$\sp{2+}$ stores in calf oocytes. Injection of near threshold concentrations of inositol 1,4,5-trishphosphate (InsP$\sb3),$ used to test the sensitivity of the InsP$\sb3$R, released significantly less Ca$\sp{2+}$ in calf than cow oocytes. Furthermore, injection of a porcine sperm factor elicited Ca$\sp{2+}$ release in calf oocytes, however, these responses did not exhibit the frequency or amplitude known to be characteristic of cow oocytes. These results suggested that the Ca$\sp{2+}$ content of the intracellular stores was similar, but the sensitivity of the Insp$\sb3$R may be different. The activity of histone H1 and MAP kinases, which are required for the initiation and completion of meiosis was evaluated, and the presence and maturation of the InsP$\sb3$R system. Results show that following in vitro maturation, the activity of both histone H1 and MAP kinases, as well as the relative amount of the InsP$\sb3$R protein, were substantially lower in prepuberal calf oocytes when compared to oocytes of adult cattle. Together, these findings suggest that the low developmental competence of calf oocytes can be attributed, at least in part, to incomplete or delayed ooplasmic maturation.