Childhood Rigid Behaviours: The Development of a New Measure and Its Associations With Child and Parental Factors.

Currently there is no suitable measure to assess the frequency of childhood rigid behaviours. Furthermore, there is a paucity of research surrounding factors that may affect the frequency of these behaviours. The first aim of this study was therefore to create a psychometrically-sound, parent-defined measure of common childhood rigid behaviour and also to find out parental responses to these behaviours. A parent-defined measure was created and distributed to 110 parents of children aged between four and six years. This led to the development of a final 20-item measure of child rigid behaviour which was shown to have good psychometrics. The second aim of the study was to correlate frequency of rigid behaviour with other measures relating to child anxiety, parental magical ideation, parental obsessive compulsiveness and parental style. The results indicated that frequency of child rigid behaviours significantly correlated with child anxiety as well as parental obsessive compulsiveness and an Authoritarian parental style. No correlation was found between rigid behaviour and parental magical ideation. In conclusion, the study produced a new tool that assesses the frequency of child rigid behaviours in a non clinical sample. The study found that child anxiety is associated with a child’s frequency of rigid behaviour and external parental factors are also additionally associated with child rigidity

Correlation of Sex, Age, and Body Mass with Hoof Size in White-Tailed Deer from the Piedmont Wildlife Refuge, Georgia

The distal forelimbs and mandibles of 157 white-tailed deer (Odo­coileus virginianus) harvested during the 2001 fall hunting season on the Piedmont National Wildlife Refuge, Georgia, were used to explore the osteometric correlation of sex, age, and body mass with hoof size. The width of the right front, medial unguis and the linear distance from the tip of the dew-claw to the tip of the medial unguis were used as measures of hoof size. Linear regressions were calcu­lated for each osteometric parameter for each sex individually and for the sexes combined. Regression R2-values suggest that hoof width may be useful in estimating body mass, but not age. However, due to nearly complete range overlap, male white-tailed deer cannot be distinguished from females on the basis of hoof width or length

Mesenchymal stem cell therapy for traumatic and degenerative eye disease

Aims The aim of this PhD research project was to investigate the application of dental pulp stem cells (DPSC) as a treatment for traumatic and degenerative eye diseases. The accuracy and reliability of counting retinal ganglion cells (RGC) in radial retinal section was also assessed. Methods Numbers of RGC in radial retinal sections were compared to numbers in retinal wholemounts. DPSC were cultured with RGC and survival and neuritogenesis were quantified. DPSC were also transplanted intravitreally into rat models of optic neuropathy (optic nerve crush) and glaucoma and surviving RGC and regenerated axons were quantified in radial retinal sections. Results Quantifying RGC in radial retinal sections was as reliable and accurate as the current gold standard Thus, retinal wholemounts with Brn3a proved to be the most reliable marker for RGC. DPSC protected RGC from optic nerve crush-/glaucoma-induced death, promoting significant regeneration of RGC axons in the former and preserving visual function (as measured by electroretinography) in the latter. The mechanism of action, as determined in vitro, appeared to be through the secretion of multiple neurotrophic factors (NTF). Conclusions In conclusion, DPSC is a potent cell therapy in the treatment of traumatic and degenerative eye disease

Intravitreally transplanted dental pulp stem cells promote neuroprotection and axon regeneration of retinal ganglion cells after optic nerve injury

Purpose. To investigate the potential therapeutic benefit of intravitreally implanted dental pulp stem cells (DPSCs) on axotomized adult rat retinal ganglion cells (RGCs) using in vitro and in vivo neural injury models. Methods. Conditioned media collected from cultured rat DPSCs and bone marrow-derived mesenchymal stem cells (BMSCs) were assayed for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) secretion using ELISA. DPSCs or BMSCs were cocultured with retinal cells, with or without Fc-TrK inhibitors, in a Transwell system, and the number of surviving βIII-tubulin+ retinal cells and length/number of βIII-tubulin+ neurites were quantified. For the in vivo study, DPSCs or BMSCs were transplanted into the vitreous body of the eye after a surgically induced optic nerve crush injury. At 7, 14, and 21 days postlesion (dpl), optical coherence tomography (OCT) was used to measure the retinal nerve fiber layer thickness as a measure of axonal atrophy. At 21 dpl, numbers of Brn-3a+ RGCs in parasagittal retinal sections and growth-associated protein-43+ axons in longitudinal optic nerve sections were quantified as measures of RGC survival and axon regeneration, respectively. Results. Both DPSCs and BMSCs secreted NGF, BDNF, and NT-3, with DPSCs secreting significantly higher titers of NGF and BDNF than BMSCs. DPSCs, and to a lesser extent BMSCs, promoted statistically significant survival and neuritogenesis/axogenesis of βIII-tubulin+ retinal cells in vitro and in vivo where the effects were abolished after TrK receptor blockade. Conclusions. Intravitreal transplants of DPSCs promoted significant neurotrophin-mediated RGC survival and axon regeneration after optic nerve injury

The role of miRNA in retinal ganglion cell health and disease

miRNA are short non-coding RNA responsible for the knockdown of proteins through their targeting and silencing of complimentary mRNA sequences. The miRNA landscape of a cell thus affects the levels of its proteins and has significant consequences to its health. Deviations in this miRNA landscape have been implicated in a variety of neurodegenerative diseases and have also garnered interest as targets for treatment. Retinal ganglion cells are the sole projection neuron of the retina with their axons making up the optic nerve. They are a focus of study not only for their importance in vision and the myriad of blinding diseases characterized by their dysfunction and loss, but also as a model of other central nervous system diseases such as spinal cord injury and traumatic brain injury. This review summarizes current knowledge on the role of miRNA in retinal ganglion cell function, highlighting how perturbations can result in disease, and how modulating their abundance may provide a novel avenue of therapeutic research

TNFα-mediated priming of mesenchymal stem cells enhances their neuroprotective effect on retinal ganglion cells

Purpose: To determine whether priming of bone marrow mesenchymal stem cells (MSCs) by signals from injured retina, particularly tumor necrosis factor α (TNFα), increase their exosomes’ neuroprotective efficacy on retinal ganglion cells (RGCs). Methods: MSCs were primed with retinal cell culture conditioned medium, with or without the TNFα blocker etanercept or TNFα prior to isolation of exosomes. MSC conditioned medium or exosomes were added to rat retinal cultures or human stem cell–derived retinal ganglion cell (hRGC) cultures, and RGC neuroprotective effects were quantified. Luminex assays were used to compare primed versus unprimed exosomes. Results: MSC conditioned medium and exosomes exerted a significant neuroprotective effect on injured rat and hRGC. This effect was significantly increased after MSCs were primed with retinal conditioned medium or TNFα. Blocking of TNFα signaling with etanercept prevented priming-induced RGC neuroprotective efficacy. Priming increased PEDF and VEGF-AA exosomal abundance. Conclusions: MSC exosomes promote RGC survival not just in rodent retinal cultures but also with hRGC. Their efficacy can be further enhanced through TNFα priming with the mechanism of action potentially mediated, at least in part, through increased levels of PEDF and VEGF-AA

Extracellular vesicle therapy for retinal diseases

Extracellular vesicles (EV), which include exosomes and microvesicles, are secreted from virtually every cell. EV contain mRNA, miRNA, lipids and proteins and can deliver this expansive cargo into nearby cells as well as over long distances via the blood stream. Great interest has been given to them for their role in cell to cell communication, disease progression, or as biomarkers, and more recent studies have interrogated their potential as a therapeutic that may replace paracrine-acting cell therapies. The retina is a conveniently accessible component of the central nervous system and the proposed paradigm for the testing of many cell therapies. Recently, several studies have been published demonstrating that the delivery of EV/exosomes into the eye can elicit significant therapeutic effects in several models of retinal disease. We summarize results from currently available studies, demonstrating their efficacy in multiple eye disease models as well as highlighting where future research efforts should be directed

Bone marrow-derived mesenchymal stem cells-derived exosomes promote survival of retinal ganglion cells through miRNA-dependent mechanisms

The loss of retinal ganglion cells (RGC) and their axons is one of the leading causes of blindness and includes traumatic (optic neuropathy) and degenerative (glaucoma) eye diseases. Although no clinical therapies are in use, mesenchymal stem cells (MSC) have demonstrated significant neuroprotective and axogenic effects on RGC in both of the aforementioned models. Recent evidence has shown that MSC secrete exosomes, membrane enclosed vesicles (30–100 nm) containing proteins, mRNA and miRNA which can be delivered to nearby cells. The present study aimed to isolate exosomes from bone marrow‐derived MSC (BMSC) and test them in a rat optic nerve crush (ONC) model. Treatment of primary retinal cultures with BMSC‐exosomes demonstrated significant neuroprotective and neuritogenic effects. Twenty‐one days after ONC and weekly intravitreal exosome injections; optical coherence tomography, electroretinography, and immunohistochemistry was performed. BMSC‐derived exosomes promoted statistically significant survival of RGC and regeneration of their axons while partially preventing RGC axonal loss and RGC dysfunction. Exosomes successfully delivered their cargo into inner retinal layers and the effects were reliant on miRNA, demonstrated by the diminished therapeutic effects of exosomes derived from BMSC after knockdown of Argonaute‐2, a key miRNA effector molecule. This study supports the use of BMSC‐derived exosomes as a cell‐free therapy for traumatic and degenerative ocular disease

Retinal ganglion cell neuroprotection by growth factors and exosomes: Lessons from mesenchymal stem cells

Retinal ganglions cells (RGCs) are responsible for propagating electrochemical information from the eye to the brain along their axons which make up the optic nerve. The loss of RGCs is characteristic in several conditions such as glaucoma and traumatic optic neuropathy and leads to visual loss and blindness. While no therapy exists to directly treat RGCs, the use of bone marrow-derived mesenchymal stem cells (BMSCs) has shown promise in eliciting significant RGC neuroprotection