Although 24R,25(OH)2D3 has been implicated in bone development, its biological role and mechanism of action remain controversial. In search for evidence of a receptor, nuclear and cytosol extracts were isolated from mandibles and calvaria of E17.5 mice. Competition and saturation analysis identified a saturable, specific and high affinity (Kd=1.1nM) 24R,25(OH) 2D3 binding-protein. The results of these and sucrose sedimentation studies indicate that this protein is not vitamin D receptor (VDR) or vitamin D binding protein (DBP). Tissue specificity experiments suggest that this putative receptor is also present in liver but not brain. / pBDGal4-hRXRalpha bait was used to screen neonate and embryonal mandible/calvaria cDNA libraries using the yeast two-hybrid system. PCR screening was also performed using primers from the zinc-finger region of the VDR. To date no positive clones have been identified. Isolation of this putative receptor will provide valuable insight into the mechanism of this metabolite's role in bone development.

Controversy exists regarding the integrity of the nervous system in the young infant with a congenital heart defect who must undergo corrective or palliative open heart surgery. Neurodevelopmental sequelae have been largely attributed to surgical events and procedures without careful evaluation of preoperative neurologic status. Very few studies have explored whether pre-existing neurologic abnormalities are evident prior to surgery. / The objective of this study was to determine if newborns with congenital heart defects demonstrate abnormalities in neurobehavioral status prior to surgery, as measured by neurologic and neurobehavioral performance as well as somatosensory evoked potentials. The results indicated that neurobehavioral abnormalities were common and included muscle tone abnormalities, seizures, microcephaly, poor state regulation, poor orienting responses, and abnormal feeding patterns. The overall likelihood of neurobehavioral abnormalities was not influenced by clinical indicators of cardiorespiratory compromise. Findings suggest that the prevalence of neurobehavioral abnormalities in this population has been underappreciated and may warrant routine developmental screening.

Ultrasound is a non-invasive diagnostic tool that could provide important information about pulmonary maturity. Quantitative ultrasound techniques that relate lung tissue acoustic properties, i.e. acoustic velocity, attenuation, and scattering, to its physical properties, such as, elastic and structural properties, have been reviewed. B-mode techniques were equipment dependent and produced conflicting results. A-mode techniques are less dependent on the measuring equipment and could provide more accurate information about lung development. A-node techniques were applied to the study of regional differences within the fetal lung. The accuracy of these techniques could be instrumental to the eventual determination of lung maturation. To pursue this possibility, the alveolar regions across the upper, middle, and lower lobes of physiologically mature normal preterm lamb lungs were scanned to determine their acoustic properties within the frequency range of 1-15 MHz. Average speed of sound, attenuation and size of backscatterers were found to be independent of lung regions. Comparison between the lung mean size of backscatterers and mean alveolar sac diameter, histologically measured from the whole lung, showed that these data were not statistically different. This suggested that the collagen rich alveolar sac septal walls were the principal sources of scattering. Histological measurements on the size of alveolar sacs across different regions of the lung were also independent of the lung regions. The results of this study on the fetal lamb lungs suggested that A-mode ultrasound is sensitive to lung developmental changes. The ability of A-mode ultrasound to determine lung maturity appears promising. Further experiments on regional lung development and lung maturation at the pre and post-surfactant synthesis stages of the gestational life may establish the basis for an accurate and risk-free ultrasound assessment of lung maturation that is reliable in a clinical setting

This study investigated the conditions under which communicative interactions were facilitated in hearing-impaired children and their caregivers as compared to normally hearing children and their caregivers. Participants were six normally hearing children and five hearing-impaired children, and their caregivers. Each interactant's communicative behaviors were coded for the intentions conveyed, discourse turn types, and verbal or nonverbal modalities of expression. Patterns emerged regarding caregiver communicative behaviors that facilitated children's participation in ongoing conversations. Caregiver behaviors most likely to be followed by on-topic responses from normally hearing and hearing-impaired children included caregiver requests, messages expressed through simultaneous verbal and nonverbal means, and turns that extended topics of conversations. Hearing-impaired children tended to produce more partially inadequate on-topic responses to their caregivers' turns than did the normally hearing children. Results are discussed with regard to clinical implications for the improvement or intervention with hearing-impaired children.

This doctoral thesis reports a series of studies aimed at exploring the control of body equilibrium during perturbations of the bipedal stance in healthy humans, and its modifications by aging and Parkinson's disease (PD). With the use of two unique experimental paradigms, we investigated reflex interactions during forward whole head-and-body tilts (WHBT) in healthy young and elderly subjects, and PD patients. We discovered that the excitability of extensor muscle responses to the stimulation of flexion reflex (FR) afferents was enhanced during WHBTs in young normal subjects. Such a functional output suggested that the specific needs of balance maintenance could have governed the reflex interaction during WHBTs rather than limb withdrawal. / A significantly smaller proportion of elderly than young subjects showed an increase or a decrease of the FR in their ipsilateral tibialis anterior muscle (iTA) during WHBT. This indicated a lack of FR modifiability during dynamic perturbations of standing balance with aging. Such a change in reflex interaction could originate from a defect in the sensorimotor integration needed for the proper control of forward WHBT. / PD patients were first characterized by a large increase in the excitability of their muscle responses to forward WHBT, which was accompanied by a much smaller increase in soleus H-reflex excitability during similar WHBTs. Second, they manifested a reduced FR modifiability during WHBT in comparison with age-matched normal subjects. Our findings suggest that PD might involve a specific difficulty to generate appropriate output from the interaction between flexor and extensor muscle responses. We hypothesise that an abnormal control of spinal interneurons in PD could be responsible for the tilting disorder and altered reflex interactions observed in these patients.

The scientific aim of computational neuroanatomy using magnetic resonance imaging (MRI) is to quantify inter- and intra-subject morphological variabilities. A unified statistical framework for analyzing temporally varying brain morphology is presented. Based on the mathematical framework of differential geometry, the deformation of the brain is modeled and key morphological descriptors such as length, area, volume dilatation and curvature change are computed. To increase the signal-to-noise ratio, Gaussian kernel smoothing is applied to 3D images. For 2D curved cortical surface, diffusion smoothing, which generalizes Gaussian kernel smoothing, has been developed. Afterwards, statistical inference is based on the excursion probability of random fields defined on manifolds. / This method has been applied in localizing the regions of brain tissue growth and loss in a group of 28 normal children and adolescents. It is shown that children's brains change dramatically in localized areas even after age 12.

Introduction: Hirschsprung’s Disease (HD) is the congenital absence of ganglion cells (GCs) within the distal intestine. Our objectives are to determine if apoptosis of myenteric GCs occurs during human development and to determine if myenteric GC apoptosis or injury contributes to HD. Materials and Methods: Apoptosis of myenteric GCs was assessed in archived fetal intestinal tissue (n = 4; 15-41 weeks gestational age) and in HD at the transition zone (TZ) (n = 6) using anti-cleaved caspase-3. Immunohistochemistry for GFAP, CD68, HLA-DR and APP was used to assess the presence of enteric reactive changes. Results: No activated caspase-3 expression was present in the myenteric GCs of the developing human intestine or the TZ of HD. No significant increase in GFAP, CD68, HLA-DR or APP expression was present. Conclusions: Apoptosis does not appear to occur during the development of the human myenteric plexus or, in conjunction with GC injury, in HD.

This study was designed to compare the behavioral pain responses of 2-month-old Canadian-born Chinese babies receiving a routine immunization to those of Caucasian infants in similar situations. Two groups of 26 infants were obtained through convenience from a pediatric clinic held by a Chinese pediatrician at the Chinese Hospital and a suburban pediatric practice of a large Canadian city. Facial expression using the Neonatal Facial Coding System (Grunau & Craig, 1987) and cry using the Fast Fourier Transform were measured during 30 seconds following the insertion of the needle. Acculturation in Chinese mothers, infant temperament, circadian rhythm, were assessed. Multivariate analysis of variance revealed significant differences in pain response between these two groups with the Chinese babies showing greater response. No significant effect of temperament, circadian rhythm, and gender was identified. This supports the presence of differences in pain response in relation to culture/race by at least 2 months of age.

The locomotor behavior of adult rats (n = 48) at different age periods was determined on five inclined plexiglass runways of different widths (24, 18, 12, 6 and 3 mm). Differences in the number (old middle-age $>$ young) were observed between the three age groups. For a subset of animals (n = 17), age-related changes were examined in the organization of the morphological properties of horseradish peroxidase (HRP)-labelled motoneurons in a representative hindlimb motoneuron pool. Data suggests that the loss of large motoneurons and soma atrophy play a role (p $<$ 0.01) in the organization of the medial gastrocnemius (MG) motoneuron pool in aged animals. The relationship between the composite motor performance score and the number of MG alpha motoneurons for individual animals reflected the continuum from young to old.

<p> In the United States, there are 507 amputations each day, a number expected to grow with the increases in obesity and diabetes. This study investigated the lived experience of yoga for amputees. The researcher studied the phenomena of amputees doing yoga&mdash;<i>ampyogis</i>&mdash;for the first time, what the amputees learned about their soma through yoga on the mat, and the significance of transference of their learning from the yoga mat to their lives off the mat. Existing literature defines rehabilitative practices for amputees to take care of daily life necessities, such as learning to walk with a prosthetic, as well as the impact of yoga on multiple populations, such as cancer survivors, those with multiple sclerosis, trauma victims, and children with attention deficit disorders. There is a current body of literature on somatic practices, moving the body with the intention to produce a certain outcome in the soma. This was a qualitative study informed by phenomenology. The researcher designed semistructured interviews to follow the participants' narratives about events that led to amputation, their postamputation felt sense of self, and the impact of yoga on shifts in their felt sense of self. Findings indicate themes of organizing principles for the ampyogis that reflect the embodied motivation to enact change on, through, and with their bodies. Themes observed included demonstrated increased capacity among ampyogis to self-accept, to appreciate their bodies and minds, and to self-generate their choices and decision-making. Findings suggest that participants shifted their somas; and increased capacity for self-accountability regarding somatic choices from, for example, feeling depressed and frustrated, to feeling more alive, balanced, and graceful. Participants reported increased capacity for self-confidence, self-appreciation, and self-accountability. This research adds to literature on yoga as a rehabilitative practice for amputees. It also adds to the body of literature on somatics and shifting the soma through intention and practice. Additionally, this study demonstrates that somatics in action creates change in the soma.</p>