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Modulation Of The Cardiomyocyte Hypertrophic Responses To Endothelin-1 By Adipocytes, Suresh Chandra Bairwa

Electronic Thesis and Dissertation Repository

Leptin and adiponectin are the adipokines that are shown to exert pro-hypertrophic and anti-hypertrophic effects respectively, in cardiomyocytes. We sought to determine the direct interaction between the adipocytes and cardiomyocytes during endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy and determine the role of leptin and adiponectin.

The adipose tissue conditioned medium (ACM) inhibited the ET-1-induced hypertrophy in a concentration-dependent manner and this anti-hypertrophic effect was more potent or reversed in the presence of leptin receptor antagonist (LRA; 0.1 nM) or adiponectin receptor-1 antibody (ARA; 100 ng/mL), respectively. ACM from heart failure rats induced by coronary artery ligation or obese rats did not mitigate …

Vitamin D And White Matter Abnormalities In Older Adults: A Cross-Sectional Neuroimaging Study., C Annweiler, T Annweiler, R Bartha, F R Herrmann, R Camicioli, O Beauchet

Medical Biophysics Publications

BACKGROUND AND PURPOSE: Morphological brain changes related to hypovitaminosis D have been poorly studied. In particular, the age-related decrease in vitamin D concentrations may explain the onset of white matter abnormalities (WMA) in older adults. Our objectives were (i) to investigate whether there was an association between serum 25-hydroxyvitamin D (25OHD) concentration and the grade of WMA in older adults and (ii) to determine whether the location of WMA was associated with 25OHD concentration.

METHODS: One hundred and thirty-three Caucasian older community-dwellers with no clinical hydrocephalus (mean 71.6 ± 5.6 years; 43.6% female) received a blood test and a magnetic …

Quantitative Mri Correlates Of Hippocampal And Neocortical Pathology In Intractable Temporal Lobe Epilepsy, Maged Goubran

Electronic Thesis and Dissertation Repository

Intractable or drug-resistant epilepsy occurs in over 30% of epilepsy patients, with many of these patients undergoing surgical excision of the affected brain region to achieve seizure control. Advances in MRI have the potential to improve surgical treatment of epilepsy through improved identification and delineation of lesions. However, validation is currently needed to investigate histopathological correlates of these new imaging techniques. The purpose of this work is to investigate histopathological correlates of quantitative relaxometry and DTI from hippocampal and neocortical specimens of intractable TLE patients. To achieve this goal I developed and evaluated a pipeline for histology to in-vivo MRI …

Mirror Reversal And Visual Rotation Are Learned And Consolidated Via Separate Mechanisms: Recalibrating Or Learning De Novo?, Sebastian Telgen, Darius Parvin, Jörn Diedrichsen

Brain and Mind Institute Researchers' Publications

Motor learning tasks are often classified into adaptation tasks, which involve the recalibration of an existing control policy (the mapping that determines both feedforward and feedback commands), and skill-learning tasks, requiring the acquisition of new control policies. We show here that this distinction also applies to two different visuomotor transformations during reaching in humans: Mirror-reversal (left-right reversal over a mid-sagittal axis) of visual feedback versus rotation of visual feedback around the movement origin. During mirror-reversal learning, correct movement initiation (feedforward commands) and online corrections (feedback responses) were only generated at longer latencies. The earliest responses were directed into a nonmirrored …

Roles Of P2x7 Receptors In Adipose And Skeletal Tissues Of Mice, Kim L. Beaucage

Electronic Thesis and Dissertation Repository

P2X7 is an ATP-gated ion channel in the plasma membrane of a number of cell types. Previous in vitro studies show that P2X7 plays a role in regulating the differentiation of osteoblasts and adipocytes from mesenchymal precursors, as well as cellular metabolism and energy homeostasis. Furthermore, P2X7 has been implicated in mediating the effects of mechanical stimuli in bone. Our objective was to investigate the roles of P2X7, mechanical vibration, and their possible interaction in regulating body composition in vivo. We developed a novel method to monitor body composition during growth and aging in mice using micro-computed tomography (Chapter …

Reciprocity In Microbiome And Immune System Interactions And Its Implications In Disease And Health., Enayat Nikoopour, Bhagirath Singh

Microbiology & Immunology Publications

Adaptation of the whole microbial normal flora residing in a host to its natural habitat over an evolutionary period has resulted in peaceful coexistence with mutual benefits for both microbiota and host in steady state. This symbiotic relationship between host and microbiota has a significant impact on shaping the immune response in the host to achieve an immune tolerance to microbiota but retaining the ability to respond to invading pathogens. Perturbation of this balance by manipulation of microbial communities in the host can lead to immune dysregulation and susceptibility to diseases. By studying the host in the absence of microbiota …

Quantitative Susceptibility Imaging Of Tissue Microstructure Using Ultra-High Field Mri, David A. Rudko

Electronic Thesis and Dissertation Repository

This thesis has used ultra-high field (UHF) magnetic resonance imaging (MRI) to investigate the fundamental relationships between tissue microstructure and such susceptibility-based contrast parameters as the apparent transverse relaxation rate (R₂^*), the local Larmor frequency shift (LFS) and quantitative volume magnetic susceptibility (QS). The interaction of magnetic fields with biological tissues results in shifts in the LFS which can be used to distinguish underlying cellular architecture. The LFS is also linked to the relaxation properties of tissues in a gradient echo MRI sequence. Equally relevant, histological analysis has identified iron and myelin as two major sources of …

Investigating The Relation Between Striatal Volume And Iq., Penny A Macdonald, Hooman Ganjavi, D Louis Collins, Alan C Evans, Sherif Karama

Brain and Mind Institute Researchers' Publications

The volume of the input region of the basal ganglia, the striatum, is reduced with aging and in a number of conditions associated with cognitive impairment. The aim of the current study was to investigate the relation between the volume of striatum and general cognitive ability in a sample of 303 healthy children that were sampled to be representative of the population of the United States. Correlations between the WASI-IQ and the left striatum, composed of the caudate nucleus and putamen, were significant. When these data were analyzed separately for male and female children, positive correlations were significant for the …

The Impact Of Multisensory Integration Deficits On Speech Perception In Children With Autism Spectrum Disorders., Ryan A Stevenson, Magali Segers, Susanne Ferber, Morgan D Barense, Mark T Wallace

Brain and Mind Institute Researchers' Publications

Speech perception is an inherently multisensory process. When having a face-to-face conversation, a listener not only hears what a speaker is saying, but also sees the articulatory gestures that accompany those sounds. Speech signals in visual and auditory modalities provide complementary information to the listener (Kavanagh and Mattingly, 1974), and when both are perceived in unison, behavioral gains in in speech perception are observed (Sumby and Pollack, 1954). Notably, this benefit is accentuated when speech is perceived in a noisy environment (Sumby and Pollack, 1954). To achieve a behavioral gain from multisensory processing of speech, however, the auditory and visual …

Links Between White Matter Microstructure And Cortisol Reactivity To Stress In Early Childhood: Evidence For Moderation By Parenting., Haroon I Sheikh, Marc F Joanisse, Sarah M Mackrell, Katie R Kryski, Heather J Smith, Shiva M Singh, Elizabeth P Hayden

Brain and Mind Institute Researchers' Publications

Activity of the hypothalamic-pituitary-adrenal axis (measured via cortisol reactivity) may be a biological marker of risk for depression and anxiety, possibly even early in development. However, the structural neural correlates of early cortisol reactivity are not well known, although these would potentially inform broader models of mechanisms of risk, especially if the early environment further shapes these relationships. Therefore, we examined links between white matter architecture and young girls' cortisol reactivity and whether early caregiving moderated these links. We recruited 45 6-year-old girls based on whether they had previously shown high or low cortisol reactivity to a stress task at …

Sign Language Ability In Young Deaf Signers Predicts Comprehension Of Written Sentences In English., Kathy N Andrew, Jennifer Hoshooley, Marc F Joanisse

Brain and Mind Institute Researchers' Publications

We investigated the robust correlation between American Sign Language (ASL) and English reading ability in 51 young deaf signers ages 7;3 to 19;0. Signers were divided into 'skilled' and 'less-skilled' signer groups based on their performance on three measures of ASL. We next assessed reading comprehension of four English sentence structures (actives, passives, pronouns, reflexive pronouns) using a sentence-to-picture-matching task. Of interest was the extent to which ASL proficiency provided a foundation for lexical and syntactic processes of English. Skilled signers outperformed less-skilled signers overall. Error analyses further indicated greater single-word recognition difficulties in less-skilled signers marked by a higher …

Sensitivity Of Human Auditory Cortex To Rapid Frequency Modulation Revealed By Multivariate Representational Similarity Analysis., Marc F Joanisse, Diedre D Desouza

Brain and Mind Institute Researchers' Publications

Functional Magnetic Resonance Imaging (fMRI) was used to investigate the extent, magnitude, and pattern of brain activity in response to rapid frequency-modulated sounds. We examined this by manipulating the direction (rise vs. fall) and the rate (fast vs. slow) of the apparent pitch of iterated rippled noise (IRN) bursts. Acoustic parameters were selected to capture features used in phoneme contrasts, however the stimuli themselves were not perceived as speech per se. Participants were scanned as they passively listened to sounds in an event-related paradigm. Univariate analyses revealed a greater level and extent of activation in bilateral auditory cortex in response …