Characterisation of the pathogenic effects of the in vivo expression of an ALS-linked mutation in D-amino acid oxidase: Phenotype and loss of spinal cord motor neurons

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset neuromuscular disorder characterised by selective loss of motor neurons leading to fatal paralysis. Current therapeutic approaches are limited in their effectiveness. Substantial advances in understanding ALS disease mechanisms has come from the identification of pathogenic mutations in dominantly inherited familial ALS (FALS). We previously reported a coding mutation in D-amino acid oxidase (DAOR199W) associated with FALS. DAO metabolises D-serine, an essential co-agonist at the N-Methyl-D-aspartic acid glutamate receptor subtype (NMDAR). Using primary motor neuron cultures or motor neuron cell lines we demonstrated that expression of DAOR199W, promoted the formation of ubiquitinated protein aggregates, activated autophagy and increased apoptosis. The aim of this study was to characterise the effects of DAOR199W in vivo, using transgenic mice overexpressing DAOR199W. Marked abnormal motor features, e.g. kyphosis, were evident in mice expressing DAOR199W, which were associated with a significant loss (19%) of lumbar spinal cord motor neurons, analysed at 14 months. When separated by gender, this effect was greater in females (26%; p< 0.0132). In addition, we crossed the DAOR199W transgenic mouse line with the SOD1G93A mouse model of ALS to determine whether the effects of SOD1G93A were potentiated in the double transgenic line (DAOR199W/SOD1G93A). Although overall survival was not affected, onset of neurological signs was significantly earlier in female double transgenic animals than their female SOD1G93A littermates (125 days vs 131 days, P = 0.0239). In summary, some significant in vivo effects of DAOR199W on motor neuron function (i.e. kyphosis and loss of motor neurons) were detected which were most marked in females and could contribute to the earlier onset of neurological signs in double transgenic females compared to SOD1G93A littermates, highlighting the importance of recognizing gender effects present in animal models of ALS

The legal and ethical framework governing Body Donation in Europe-1st update on current practice

Previously, we have reported on the legal and ethical aspects and current practice of body donation in several European countries, reflecting cultural and religious variations as well as different legal and constitutional frameworks. We have also established good practice in body donation. Here we shall further extend the legal and ethical frameworks in place and also focus on novelties in the law and different directives. Of particular interest are points that address the commercialization of human bodies and body parts and weaknesses in the legal directives. Therefore, it is important to define what is ethical and what needs to be considered unethical in body donation and the subsequent utilisation of human bodies for teaching and research.peer-reviewe

The Anatomical Society’s Core Anatomy Syllabus for Dental Undergraduates

The Anatomical Society has developed a series of learning outcomes in consultation with dentists, dental educators and anatomists delivering anatomical content to undergraduate dental students. A modified Delphi methodology was adopted to select experts within the field that would recommend core anatomical content in undergraduate dental programmes throughout the UK. Utilising the extensive learning outcomes from two UK Dental Schools, and neuroanatomy learning outcomes that remained outside the Anatomical Society's Core Gross Anatomy Syllabus for Medical Students, a modified Delphi technique was utilised to develop dental anatomical learning outcomes relevant to dental graduates. The Delphi panel consisted of 62 individuals (n = 62) from a wide pool of educators associated with the majority of undergraduate dental schools in the UK, representing a broad spectrum of UK Higher Education Institutions. The output from this study was 147 anatomical learning outcomes deemed to be applicable to all dental undergraduate programmes in the UK. The new recommended core anatomy syllabus for dental undergraduates, grouped into body regions, offers a comprehensive anatomical framework with which to scaffold clinical practice. The syllabus, presented as a set of learning outcomes, may be used in a variety of pedagogic situations, including where anatomy teaching exists within an integrated dental curriculum (both horizontally in the basic sciences part of the curriculum and vertically within the clinical years)

Musculotopic organization of the motor neurons supplying the mouse hindlimb muscles: a quantitative study using Fluoro-Gold retrograde tracing

We have mapped the motor neurons (MNs) supplying the major hindlimb muscles of transgenic (C57/BL6J-ChAT-EGFP) and wild-type (C57/BL6J) mice. The fluorescent retrograde tracer Fluoro-Gold was injected into 19 hindlimb muscles. Consecutive transverse spinal cord sections were harvested, the MNs counted, and the MN columns reconstructed in 3D. Three longitudinal MN columns were identified. The dorsolateral column extends from L4 to L6 and consists of MNs innervating the crural muscles and the foot. The ventrolateral column extends from L1 to L6 and accommodates MNs supplying the iliopsoas, gluteal, and quadriceps femoris muscles. The middle part of the ventral horn hosts the central MN column, which extends between L2–L6 and consists of MNs for the thigh adductor, hamstring, and quadratus femoris muscles. Within these longitudinal columns, the arrangement of the different MN groups reflects their somatotopic organization. MNs innervating muscles developing from the dorsal (e.g., quadriceps) and ventral muscle mass (e.g., hamstring) are situated in the lateral and medial part of the ventral gray, respectively.MN pools belonging to proximal muscles (e.g., quadratus femoris and iliopsoas) are situatedventral to those supplying more distal ones (e.g., plantar muscles). Finally, MNs innervatingflexors (e.g., posterior crural muscles) are more medial than those belonging to extensors ofthe same joint (e.g., anterior crural muscles). These data extend and modify the MN maps in the recently published atlas of the mouse spinal cord and may help when assessing neuronal loss associated with MN diseases

Online Assessment of Applied Anatomy Knowledge: The Effect of Images on Medical Students' Performance

Anatomical examinations have been designed to assess topographical and/or applied knowledge of anatomy with or without the inclusion of visual resources such as cadaveric specimens or images, radiological images, and/or clinical photographs. Multimedia learning theories have advanced the understanding of how words and images are processed during learning. However, the evidence of the impact of including anatomical and radiological images within written assessments is sparse. This study investigates the impact of including images within clinically oriented single-best-answer questions on students' scores in a tailored online tool. Second-year medical students (n = 174) from six schools in the United Kingdom participated voluntarily in the examination, and 55 students provided free-text comments which were thematically analyzed. All questions were categorized as to whether their stimulus format was purely textual or included an associated image. The type (anatomical and radiological image) and deep structure of images (question referring to a bone or soft tissue on the image) were taken into consideration. Students scored significantly better on questions with images compared to questions without images (P

Conduction in ulnar nerve bundles that innervate the proximal and distal muscles: a clinical trial

<p>Abstract</p> <p>Background</p> <p>This study aims to investigate and compare the conduction parameters of nerve bundles in the ulnar nerve that innervates the forearm muscles and hand muscles; routine electromyography study merely evaluates the nerve segment of distal (hand) muscles.</p> <p>Methods</p> <p>An electrophysiological evaluation, consisting of velocities, amplitudes, and durations of ulnar nerve bundles to 2 forearm muscles and the hypothenar muscles was performed on the same humeral segment.</p> <p>Results</p> <p>The velocities and durations of the compound muscle action potential (CMAP) of the ulnar nerve bundle to the proximal muscles were greater than to distal muscles, but the amplitudes were smaller.</p> <p>Conclusions</p> <p>Bundles in the ulnar nerve of proximal muscles have larger neuronal bodies and thicker nerve fibers than those in the same nerve in distal muscles, and their conduction velocities are higher. The CMAPs of proximal muscles also have smaller amplitudes and greater durations. These findings can be attributed to the desynchronization that is caused by a wider range of distribution in nerve fiber diameters.</p> <p>Conduction parameters of nerve fibers with different diameters in the same peripheral nerve can be estimated.</p

The Anatomical Society core regional anatomy syllabus for undergraduate medicine

The Anatomical Society's core syllabus for anatomy (2003 and later refined in 2007) set out a series of learning outcomes that an individual medical student should achieve on graduation. The core syllabus, with 182 learning outcomes grouped in body regions, referenced in the General Medical Council's Teaching Tomorrow's Doctors, was open to criticism on the grounds that the learning outcomes were generated by a relatively small group of anatomists, albeit some of whom were clinically qualified. We have therefore used a modified Delphi technique to seek a wider consensus. A Delphi panel was constructed involving 'experts' (n = 39). The revised core syllabus of 156 learning outcomes presented here is applicable to all medical programmes and may be used by curriculum planners, teachers and students alike in addressing the perennial question: 'What do I need to know ?

Motor Unit Abnormalities in Dystonia musculorum Mice

Dystonia musculorum (dt) is a mouse inherited sensory neuropathy caused by mutations in the dystonin gene. While the primary pathology lies in the sensory neurons of dt mice, the overt movement disorder suggests motor neurons may also be affected. Here, we report on the contribution of motor neurons to the pathology in dt27J mice. Phenotypic dt27J mice display reduced alpha motor neuron cell number and eccentric alpha motor nuclei in the ventral horn of the lumbar L1 spinal cord region. A dramatic reduction in the total number of motor axons in the ventral root of postnatal day 15 dt27J mice was also evident. Moreover, analysis of the trigeminal nerve of the brainstem showed a 2.4 fold increase in number of degenerating neurons coupled with a decrease in motor neuron number relative to wild type. Aberrant phosphorylation of neurofilaments in the perikaryon region and axonal swellings within the pre-synaptic terminal region of motor neurons were observed. Furthermore, neuromuscular junction staining of dt27J mouse extensor digitorum longus and tibialis anterior muscle fibers showed immature endplates and a significant decrease in axon branching compared to wild type littermates. Muscle atrophy was also observed in dt27J muscle. Ultrastructure analysis revealed amyelinated motor axons in the ventral root of the spinal nerve, suggesting a possible defect in Schwann cells. Finally, behavioral analysis identified defective motor function in dt27J mice. This study reveals neuromuscular defects that likely contribute to the dt27J pathology and identifies a critical role for dystonin outside of sensory neurons

Striking Denervation of Neuromuscular Junctions without Lumbar Motoneuron Loss in Geriatric Mouse Muscle

Reasons for the progressive age-related loss of skeletal muscle mass and function, namely sarcopenia, are complex. Few studies describe sarcopenia in mice, although this species is the mammalian model of choice for genetic intervention and development of pharmaceutical interventions for muscle degeneration. One factor, important to sarcopenia-associated neuromuscular change, is myofibre denervation. Here we describe the morphology of the neuromuscular compartment in young (3 month) compared to geriatric (29 month) old female C57Bl/6J mice. There was no significant difference in the size or number of motoneuron cell bodies at the lumbar level (L1–L5) of the spinal cord at 3 and 29 months. However, in geriatric mice, there was a striking increase (by ∼2.5 fold) in the percentage of fully denervated neuromuscular junctions (NMJs) and associated deterioration of Schwann cells in fast extensor digitorum longus (EDL), but not in slow soleus muscles. There were also distinct changes in myofibre composition of lower limb muscles (tibialis anterior (TA) and soleus) with a shift at 29 months to a faster phenotype in fast TA muscle and to a slower phenotype in slow soleus muscle. Overall, we demonstrate complex changes at the NMJ and muscle levels in geriatric mice that occur despite the maintenance of motoneuron cell bodies in the spinal cord. The challenge is to identify which components of the neuromuscular system are primarily responsible for the marked changes within the NMJ and muscle, in order to selectively target future interventions to reduce sarcopenia

Plasma Neurofilament Heavy Chain Levels Correlate to Markers of Late Stage Disease Progression and Treatment Response in SOD1(G93A) Mice that Model ALS

Background: Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disorder characterised by progressive degeneration of motor neurons leading to death, typically within 3–5 years of symptom onset. The diagnosis of ALS is largely reliant on clinical assessment and electrophysiological findings. Neither specific investigative tools nor reliable biomarkers are currently available to enable an early diagnosis or monitoring of disease progression, hindering the design of treatment trials. Methodology/Principal Findings: In this study, using the well-established SOD1G93A mouse model of ALS and a new in-house ELISA method, we have validated that plasma neurofilament heavy chain protein (NfH) levels correlate with both functional markers of late stage disease progression and treatment response. We detected a significant increase in plasma levels of phosphorylated NfH during disease progression in SOD1G93A mice from 105 days onwards. Moreover, increased plasma NfH levels correlated with the decline in muscle force, motor unit survival and, more significantly, with the loss of spinal motor neurons in SOD1 mice during this critical period of decline. Importantly, mice treated with the disease modifying compound arimoclomol had lower plasma NfH levels, suggesting plasma NfH levels could be validated as an outcome measure for treatment trials. Conclusions/Significance: These results show that plasma NfH levels closely reflect later stages of disease progression and therapeutic response in the SOD1G93A mouse model of ALS and may potentially be a valuable biomarker of later disease progression in ALS