Cell and Developmental Biology Commons^™

Viewing The Extracellular Matrix: An Imaging Method For Tissue Engineering, Michael Drakopoulos, Sarah Calve

The Summer Undergraduate Research Fellowship (SURF) Symposium

The field of regenerative medicine seeks to create replacement tissues and organs, both to repair deficiencies in biological function and to treat structural damage caused by injury. Scaffoldings mimicking extracellular matrix (ECM), the structure to which cells attach to form tissues, have been developed from synthetic polymers and also been prepared by decellularizing adult tissue. However, the structure of ECM undergoes significant remodeling during natural tissue repair, suggesting that ECM-replacement constructs that mirror developing tissues may promote better regeneration than those modeled on adult tissues. This work investigated the effectiveness of a method of viewing the extracellular matrix of developing …

Beclin-1 Expression Is Retained In High-Grade Serous Ovarian Cancer Yet Is Not Essential For Autophagy Induction In Vitro, Rohann J.M. Correa, Yudith R. Valdes, Trevor G. Shepherd, Gabriel E. Dimattia

Anatomy and Cell Biology Publications

Background: Autophagy is a conserved cellular self-digestion mechanism that can either suppress or promote cancer in a context-dependent manner. In ovarian cancer, prevalent mono-allelic deletion of BECN1 (a canonical autophagy-inducer) suggests that autophagy is impaired to promote carcinogenesis and that Beclin-1 is a haploinsufficient tumor suppressor. Nonetheless, autophagy is known to be readily inducible in ovarian cancer cells. We sought to clarify whether Beclin-1 expression is in fact disrupted in ovarian cancer and whether this impacts autophagy regulation.

Methods: BECN1 expression levels were assessed using The Cancer Genome Atlas (TCGA) datasets from 398 ovarian high-grade serous cystadenocarcinomas (HGSC) and protein …

Hippocalcin Response To Calcium: Do Conserved Tryptophans – W30 Or W103 – Matter?, Sunkesula K. Sagar

Graduate School of Biomedical Sciences Theses and Dissertations

Changes in intracellular calcium levels play a very important role in cell signaling, in turn, affecting neuronal functions such as memory, learning and cell death. A class of proteins called Neuronal Calcium Sensor (NCS) proteins serves to modulate the functioning of the neuronal cells in response to changes in calcium levels, and prevent neuronal apoptosis. Structurally, all NCS proteins have 4 calcium-binding EF hand motifs, although EF1 does not bind to calcium in many members. All NCS proteins have an acyl modification at the N- terminus – where a myristoyl group is added post-translationally. Hippocalcin (HPCA) is an NCS protein, …

Investigating The Role Of Cholesterol Metabolism And Synthesis In Metastasis And Radiation Response In Aggressive Subtypes Of Breast Cancer, Adam Wolfe

Dissertations and Theses (Open Access)

Aggressive breast cancers, triple-negative breast cancer (TNBC) and inflammatory breast cancer (IBC), metastasize at a high rate and are notoriously resistant to standard treatments. Research has shown diets high in cholesterol increase the incidence of aggressive breast cancers and pre-clinical research has shown cholesterol can fuel the growth of breast cancer in vivo. Studies at MD Anderson have shown that IBC patients taking cholesterol lowering drugs, statins, have improved survival outcomes, and also statins can improve the response to radiation in vitro. Furthermore, statins have been shown to target the cells with stem like-properties called cancer stem cells (CSCs) which …

Merlin Mediated Regulation Of Hair Follicle Morphogenesis, Megan K. Fentress

Dissertations and Theses (Open Access)

Epidermal homeostasis is paramount for the ongoing function of the skin as the primary barrier between a mammalian organism and the external environment. Homeostasis is achieved through a complex and delicate balance of cell death, cell proliferation and cell differentiation. Critical for regeneration and maintenance of the skin are epidermal stem cells. Within the epidermis two distinct stem cell compartments exist, the bulge and interfollicular/basal stem cell niches, which play a central role in the regeneration of the epidermis through self-renewal and contribution to the differentiated cells of the epidermis. The bulge stem cell niche is established early in epidermal …

Whole-Retina Reduced Electrophysiological Activity In Mice Bearing Retina-Specific Deletion Of Vesicular Acetylcholine Transporter, Jake Bedore, Amanda C. Martyn, Anson K. C. Li, Eric A. Dolinar, Ian S. Mcdonald, Stuart G. Coupland, Vania F. Prado, Marco A. Prado, Kathleen A. Hill

Anatomy and Cell Biology Publications

Background: Despite rigorous characterization of the role of acetylcholine in retinal development, long-term effects of its absence as a neurotransmitter are unknown. One of the unanswered questions is how acetylcholine contributes to the functional capacity of mature retinal circuits. The current study investigates the effects of disrupting cholinergic signalling in mice, through deletion of vesicular acetylcholine transporter (VAChT) in the developing retina, pigmented epithelium, optic nerve and optic stalk, on electrophysiology and structure of the mature retina. Methods & Results A combination of electroretinography, optical coherence tomography imaging and histological evaluation assessed retinal integrity in mice bearing retina-targeted (embryonic day …

Targeting Neddylation Induces Dna Damage And Checkpoint Activation And Sensitizes Chronic Lymphocytic Leukemia B Cells To Alkylating Agents, C Paiva, J C. Godbersen, A Berger, J R. Brown, A V. Danilov

Dartmouth Scholarship

Microenvironment-mediated upregulation of the B-cell receptor (BCR) and nuclear factor-κB (NF-κB) signaling in CLL cells resident in the lymph node and bone marrow promotes apoptosis evasion and clonal expansion. We recently reported that MLN4924 (pevonedistat), an investigational agent that inhibits the NEDD8-activating enzyme (NAE), abrogates stromal-mediated NF-κB pathway activity and CLL cell survival. However, the NAE pathway also assists degradation of multiple other substrates. MLN4924 has been shown to induce DNA damage and cell cycle arrest, but the importance of this mechanism in primary neoplastic B cells has not been studied. Here we mimicked the lymph node microenvironment using CD40 …

Nitric Oxide-Releasing Aspirin Suppresses Nf-Κb Signaling In Estrogen Receptor Negative Breast Cancer Cells In Vitro And In Vivo, Niharika Nath, Mitali Chattopadhyay, Deborah B. Rodes, Anna Nazarenko, Ravinder Kodela, Khosrow Kashfi

Publications and Research

Estrogen receptor negative (ER(−)) breast cancer is aggressive, responds poorly to current treatments and has a poor prognosis. The NF-κB signaling pathway is implicated in ER(−) tumorigenesis. Aspirin (ASA) is chemopreventive against ER(+) but not for ER(−) breast cancers. Nitric oxide-releasing aspirin (NO-ASA) is a safer ASA where ASA is linked to an NO-releasing moiety through a spacer. In vitro, we investigated anti-proliferation effects of NO-ASA (para- and meta-isomers) against ER(−) breast cancer cells MDA-MB-231 and SK-BR-23, effects on NF-κB signaling, and reactive oxygen species by standard techniques. In vivo, effects of NO-ASA were evaluated in a mouse xenograft model …

Selenoprotein P Influences Colitis-Induced Tumorigenesis By Mediating Stemness And Oxidative Damage., C. W. Barrett, V. K. Reddy, S. P. Short, A. K. Motley, M. K. Lintel, A. M. Bradley, T. Freeman, J. Vallance, W. Ning, B. Parang, Shenika Poindexter Toliver

Faculty and Staff Publications

Patients with inflammatory bowel disease are at increased risk for colon cancer due to augmented oxidative stress. These patients also have compromised antioxidant defenses as the result of nutritional deficiencies. The micronutrient selenium is essential for selenoprotein production and is transported from the liver to target tissues via selenoprotein P (SEPP1). Target tissues also produce SEPP1, which is thought to possess an endogenous antioxidant function. Here, we have shown that mice with Sepp1 haploinsufficiency or mutations that disrupt either the selenium transport or the enzymatic domain of SEPP1 exhibit increased colitis-associated carcinogenesis as the result of increased genomic instability and …

Targeting Il13ralpha2 Activates Stat6-Tp63 Pathway To Suppress Breast Cancer Lung Metastasis, Panagiotis Papageorgis, Sait Ozturk, Arthur W. Lambert, Christiana M. Neophytou, Alexandros Tzatsos, Chen K. Wong, Sam Thiagalingam, Andreas I. Constantinou

Anatomy and Regenerative Biology Faculty Publications

Introduction

Basal-like breast cancer (BLBC) is an aggressive subtype often characterized by distant metastasis, poor patient prognosis, and limited treatment options. Therefore, the discovery of alternative targets to restrain its metastatic potential is urgently needed. In this study, we aimed to identify novel genes that drive metastasis of BLBC and to elucidate the underlying mechanisms of action.

Methods

An unbiased approach using gene expression profiling of a BLBC progression model and in silicoleveraging of pre-existing tumor transcriptomes were used to uncover metastasis-promoting genes. Lentiviral-mediated knockdown of interleukin-13 receptor alpha 2 (IL13Ralpha2) coupled with whole-body in vivo bioluminescence imaging was …

Numerical Simulation Of Terahertz Wave Interaction With Breast Cancer Tumor Tissue Sections, Abayomi Omotola Omolewu

Graduate Theses and Dissertations

This thesis presents numerical simulation of terahertz (THz) wave interaction with breast cancer tumor tissue sections. The obtained results are expressed in THz images of heterogeneous material that mimics the excised breast cancer tissue sections. The finite-element software package ANSYS High Frequency Structural Simulator (HFSS) was used in this work. HFSS is a full wave frequency domain three-dimensional (3D) electromagnetic simulation package. In this work, four breast cancer tissue models based on pathology images were simulated and images of the models were obtained at 1 THz. An incident Gaussian beam was raster scanned over tissue model configurations and the reflected …

Effect Of Sirna Pre-Exposure On Subsequent Response To Sirna Therapy, Hamidreza Montazeri Aliabadi, Parvin Mahdipoor, Cezary Kucharski, Nicole Chan, Hasan Uludag

Pharmacy Faculty Articles and Research

PURPOSE. An alternative cancer therapy based on RNA interference (RNAi) has shown considerable promise but the possibility of resistance development is not known. This study explored the possibility of therapeutic resistance against siRNA nanoparticles in human cancer cells. METHODS. Two approaches to siRNA treatment were undertaken using lipid-modified polyethylenimines, a single high concentration (shock) and repeated increasing concentrations (gradual). The targets were Mcl-1, RPS6KA5 and KSP in MDA-MB-435 cells. RESULTS. There was no evidence of resistance development in shock-treated cells, while the decrease in mRNA levels of targeted proteins was not as robust in naïve cells in gradual treatment. However, …

Cationic Cell-Penetrating Peptides Are Potent Furin Inhibitors, Bruno Ramos-Molina, Adam N. Lick, Amir Nasrolahi Shirazi, Donghoon Oh, Rakesh Tiwari, Naglaa Salem El-Sayed, Keykavous Parang, Iris Lindberg

Pharmacy Faculty Articles and Research

Cationic cell-penetrating peptides have been widely used to enhance the intracellular delivery of various types of cargoes, such as drugs and proteins. These reagents are chemically similar to the multi-basic peptides that are known to be potent proprotein convertase inhibitors. Here, we report that both HIV-1 TAT47-57 peptide and the Chariot reagent are micromolar inhibitors of furin activity in vitro. In agreement, HIV-1 TAT47-57 reduced HT1080 cell migration, thought to be mediated by proprotein convertases, by 25%. In addition, cyclic polyarginine peptides containing hydrophobic moieties which have been previously used as transfection reagents also exhibited potent furin inhibition in vitro …

Increased Expression Of Simple Ganglioside Species Gm2 And Gm3 Detected By Maldi Imaging Mass Spectrometry In A Combined Rat Model Of A Beta Toxicity And Stroke, Sarah Caughlin, Jeffrey D. Hepburn, Dae Hee Park, Kristina Jurcic, Ken K. -C. Yeung, David F. Cechetto, Shawn N. Whitehead

Anatomy and Cell Biology Publications

The aging brain is often characterized by the presence of multiple comorbidities resulting in synergistic damaging effects in the brain as demonstrated through the interaction of Alzheimer's disease (AD) and stroke. Gangliosides, a family of membrane lipids enriched in the central nervous system, may have a mechanistic role in mediating the brain's response to injury as their expression is altered in a number of disease and injury states. Matrix-Assisted Laser Desorption Ionization (MALDI) Imaging Mass Spectrometry (IMS) was used to study the expression of A-series ganglioside species GD1a, GM1, GM2, and GM3 to determine alteration of their expression profiles in …

Characterization Of The Role That Alternative Ribonucleotide Reductases Play In Restoring Replication In The Presence Of Hydroxyurea In Escherichia Coli, Michael Sadek

PSU McNair Scholars Online Journal

DNA replication is essential for cells to grow and divide. Ribonucleotide reductase is an essential enzyme that is responsible for the formation of deoxyribonucleotides that are used in DNA synthesis during replication. Hydroxyurea is a chemotherapeutic agent that is thought to work by specifically inhibiting the ribonuceotide reductase to prevent replication. However, recent studies in E. coli have shown that following an initial period of inhibition, DNA synthesis then recovers in the presence of hydroxyurea, suggesting that the mode of death and cellular response to hydroxyurea is more complex than originally proposed. The E.coli genome encodes three ribonucleotide reductases that …

Intact Lkb1 Activity Is Required For Survival Of Dormant Ovarian Cancer Spheroids, Teresa M. Peart, Yudith R. Valdes, Rohann J.M. Correa, Elena Fazio, Monique Bertrand, Jacob Mcgee, Michel Prefontaine, Akira Sugimoto, Gabriel E. Dimattia, Trevor G. Shepherd

Anatomy and Cell Biology Publications

Metastatic epithelial ovarian cancer (EOC) cells can form multicellular spheroids while in suspension and disperse directly throughout the peritoneum to seed secondary lesions. There is growing evidence that EOC spheroids are key mediators of metastasis, and they use specific intracellular signalling pathways to control cancer cell growth and metabolism for increased survival. Our laboratory discovered that AKT signalling is reduced during spheroid formation leading to cellular quiescence and autophagy, and these may be defining features of tumour cell dormancy. To further define the phenotype of EOC spheroids, we have initiated studies of the Liver kinase B1 (LKB1)-5′-AMP-activated protein kinase (AMPK) …

Klf4-Sqstm1/P62-Associated Prosurvival Autophagy Contributes To Carfilzomib Resistance In Multiple Myeloma Models., Irene Riz, Teresa S. Hawley, Robert G. Hawley

Anatomy and Regenerative Biology Faculty Publications

Multiple myeloma (MM) is an incurable clonal plasma cell malignancy. Because of a high rate of immunoglobulin synthesis, the endoplasmic reticulum of MM cells is subjected to elevated basal levels of stress. Consequently, proteasome inhibitors, which exacerbate this stress by inhibiting ubiquitin-proteasome-mediated protein degradation, are an important new class of chemotherapeutic agents being used to combat this disease. However, MM cells still develop resistance to proteasome inhibitors such as carfilzomib. Toward this end, we have established carfilzomib-resistant derivatives of MM cell lines. We found that resistance to carfilzomib was associated with elevated levels of prosurvival autophagy, and Kruppel-like factor 4 …

Prostate Field Cancerization – Thinking Outside The Tumor, Dor Shoshan

Student Scholar Symposium Abstracts and Posters

Analysis of tumor adjacent tissue is assumed to reveal a temporal record of molecular pathways that define oncogenesis. The present study determines expression of the key transcription factor and potential marker of field cancerization early growth response 1 (EGR-1) in human prostate tissues derived from prostatectomies and biopsies. Expression was detected using immunofluorescence and quantified using ImageJ software. Accordingly, EGR-1 expression was similar in cancerous and in histologically normal adjacent tissues from prostatectomy and biopsy specimens. EGR-1 could be exploited as pre-surgical disease indicator in false negative biopsies, identify areas of repeat biopsy, and add molecular information to surgical margins.

Analyzation Of Metabolic Reprogramming In Drug-Resistant Mcf-7 Cells, Derick Han, Ho Leung, Andrew Vo

Student Scholar Symposium Abstracts and Posters

The Warburg effect states that cancer cells mainly receive their energy from anaerobic glycolysis. Thus, mitochondria play a different role in the metabolism of cancer cells as opposed to normal, healthy cells. In chemotherapy, there is always a chance of the cancer regressing. Making drug-resistant cancer cells to analyze their metabolism may change how cancer is treated. This study aimed to create drug-resistant MCF-7 cell lines with doxorubicin in order to determine the metabolic changes that have occurred in the process of becoming resistant to drug treatments.

Clinical Applications Of A Combination Chemotherapy Using 8-Chloro Camp And 8-Chloro Adenosine, Erik Munoz, Andrea Saich, Andrew Cox, Yu-An Peter Chang

Student Scholar Symposium Abstracts and Posters

Dr. Cho-Chung from the NIH first thought to use halogenated cAMP derivatives as competitive inhibitors of cAMP to slow down cancer cell mitosis. While the iodine and bromine substituted versions showed very little therapeutic actions, 8-Chloro cAMP has been shown to have strong anti-cancer effects. This has been shown in the phase II clinical trials this drug has undergone. However, these trials have had issues with solubility and toxicity. The drug is similar to vitamin C and is excreted quickly. Scientists tried to overcome this by using a peristaltic pump to give patients a continuous dosage, but this proved too …

Exploring Egr-1 As A Master Regulator Of Prostate Field Cancerization, Kristin Gabriel, Marco Bisoffi

Student Scholar Symposium Abstracts and Posters

Field cancerization denotes the presence of molecular aberrations (genetic, epigenetic, biochemical) in structurally intact cells residing in histologically normal tissues adjacent to tumors. Markers of field cancerization in prostate tissues have the potential to improve the clinical management of this malignancy through their potential to act as indicators of early disease and to serve as molecular targets for early intervention. However, for this, a detailed understanding of the functional pathways underlying field cancerization is necessary. We have recently identified four protein markers of prostate field cancerization, i.e. the key transcription factor early growth response 1 (EGR-1), the lipogenic enzyme fatty …

Effect Of Curcumin Analog Ca27 On Androgen Receptor Translocation In Prostate Cancer Cells, Lijah Vann Gardner

Student Scholar Symposium Abstracts and Posters

The androgen receptor (AR) plays an essential role in promoting the development and progression of metastatic prostate cancer and represents an important molecular target for therapeutic intervention. We have recently described a series of synthetic analogs of the natural product diferuloylmethane (curcumin), some of which induce the down-regulation of AR expression in prostate cancer cells by an as yet largely unknown mechanism of action. While such analogs may in the long term be lead structures for the development of therapeutic drugs, we hypothesize here that they represent ideal molecular probes to identify the mechanism(s) of action for AR down-regulation. We …

Increased Airway Reactivity And Hyperinsulinemia In Obese Mice Are Linked By Erk Signaling In Brain Stem Cholinergic Neurons, Luiz O. S. Leiria, Fernanda M. Arantes-Costa, Marina C. Calixto, Eduardo C. Alexandre, Rodrigo F. Moura, Franco Folli, Carla M. Prado, Marco Antonio Prado, Vania F. Prado, Licio A. Velloso, Jose Donato Jr., Edson Antunes, Milton A. Martins, Mario J. A. Saad

Anatomy and Cell Biology Publications

Obesity is a major risk factor for asthma, which is characterized by airway hyperreactivity (AHR). In obesity-associated asthma, AHR may be regulated by non-T(H)2 mechanisms. We hypothesized that airway reactivity is regulated by insulin in the CNS, and that the high levels of insulin associated with obesity contribute to AHR. We found that intracerebroventricular (ICV)-injected insulin increases airway reactivity in wild-type, but not in vesicle acetylcholine transporter knockdown (VAChT KDHOM-/-), mice. Either neutralization of central insulin or inhibition of extracellular signal-regulated kinases (ERK) normalized airway reactivity in hyperinsulinemic obese mice. These effects were mediated by insulin in cholinergic nerves located …

Effect Of Cmvil-10 On Exosome Production By Human Breast Cancer Cells, Susanna N. Basappa

Undergraduate Honors Theses

Human cytomegalovirus (HCMV) is a ubiquitous virus that infects 70-90% of the general population, primarily the immunocompromised, but has been implicated in several forms of cancer, including breast cancer. Breast cancer is the second leading cause of cancer related deaths in women in North America, usually from metastasis. Exosomes are 30-100nm vesicles produced by most cells which carry protein and RNA to cells in their microenvironment. The aim of this study is to investigate the impact of HCMV-infection of a secreted viral cytokine, cmvIL-10, on exosome production by highly metastatic breast cancer cells.

MDA-MB-231 cells were cultured in vitro, …

Structural And Functional Interactions Between Bro1 Domain Of Human Alix Protein And Nucleocapsid Packaging Rna Complex From Hiv, Scott Gross

Graduate School of Biomedical Sciences Theses and Dissertations

A virus is only as powerful as its ability to spread. Enveloped retroviruses, namely HIV-1, use exocytosis pathways that normal host cells use to release particles from the plasma membrane. The main pathways of interest in this study are the Endosomal Sorting Complex Required for Transport (ESCRT) and adjacent ALIX pathways. The ESCRT pathway is especially important for degradation of receptor/cargo complexes that form Multi-Vesicular Bodies (MVBs). Currently, there is no known therapy that targets this endosomal pathway, which would prevent the spread of the virus to other cells. The virus has adapted to jump from pathway to pathway when …

Age-Dependent Breakdown Of The Blood Brain Barrier And Associated Changes In S100b Ko Mice, Eric V. Brown

Graduate School of Biomedical Sciences Theses and Dissertations

Autoantibodies play an important role in many autoimmune diseases. Recent research has shown that breakdown of the blood brain barrier (BBB) occurs concomitant to generation of brain reactive autoantibodies in many neurodegenerative diseases, which serve as biomarkers and drivers of pathology. SI00B, a calcium binding protein found most highly expressed in astrocytes which ensheathe the BBB, has many functions in neural development and signaling. Currently literature indicates that S100B KO mice develop normally, with no phenotypic abnormalities. Here, it is demonstrated that S100B KO mice seem to develop a chronic BBB breakdown similar to that seen in human neurodegenerative diseases. …

Radium-223 For The Treatment Of Castration-Resistant Prostate Cancer, Joelle El-Amm, Jeanny B. Aragon-Ching

Medicine Faculty Publications

The vast majority of patients with metastatic castration-resistant prostate cancer (mCRPC) develop bone metastases. Bone metastases are a source of significant morbidity and affect quality of life in these patients. Several bone-targeting agents are approved for the treatment of bone metastases in prostate cancer, including bisphosphonates, denosumab, and radiopharmaceuticals. Radium-223 is a novel first-in-class alpha-emitting radiopharmaceutical that has been approved for treatment of patients with mCRPC with bone metastases. Radium-223 delivers cytotoxic radiation to the sites of bone metastases and offers the advantage of minimal myelosuppression. The landmark Phase III ALSYMPCA trial demonstrated that, in addition to providing bone-related palliation, …

Efficient In Vitro Development Of Photoreceptors From Human Pluripotent Stem Cells, Joseph C. Reynolds

Dissertations, Masters Theses, Capstones, and Culminating Projects

Degeneration of the rod and cone photoreceptors in the human retina is among the most common causes of blindness. Replacing these damaged photoreceptors may help to restore vision. Repairing the damaged retina relies on the insertion of new, healthy cells. Embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are two possible sources of photoreceptors to restore vision. Previous data shows that human ES cells and iPS cells can be differentiated into photoreceptors and transplanted into the eye to restore some vision. However, this process is inefficient, and costly. Here, we show a new method for inducing photoreceptor production …

Characterization Of Ghrelin O-Acyltransferase Active Site, Leslie Patton

Renée Crown University Honors Thesis Projects - All

Ghrelin, first discovered in 1999, is a 28-amino acid peptide hormone involved in the regulation of appetite, insulin secretion and sensitivity, and many neurological effects such as learning, memory, and depression.^1-6 Ghrelin has been identified to have a unique posttranslational octanoylation carried out by the enzyme ghrelin O-acyltransferase (GOAT). This distinctive modification is a point of interest in studying GOAT whereby blocking the acylation of the ghrelin could potentially halt the activity of the peptide hormone and provide a means of treating obesity, diabetes, and other diseases affected by ghrelin levels. The duration of my project involved working …

The Development Of Skeletal Muscle In Young Horses: An Ultrasonography And Satellite Cell Approach, Emma K. Lavigne

Honors Scholar Theses

Muscle growth in young horses is characterized by an increase in muscle cross-sectional area, which can be accomplished through the activation and differentiation of satellite cells. Satellite cells can be stimulated or inhibited in response to different cytokines and growth factors and are key mediators of muscle hypertrophy and regeneration. The aim of this study was to investigate the growth of the longissimus dorsi (LD) muscle in horses under 5 years of age and to obtain preliminary data on satellite cell behavior in foals. The area, width, height, and subcutaneous fat were measured using ultrasonography at 6-month increments over the …