Developing an Instrumented Measure of Upper Limb Function in Friedreich Ataxia.

Upper limb function for people with Friedreich ataxia determines capacity to participate in daily activities. Current upper limb measures available do not fully capture impairments related to Friedreich ataxia. We have developed an objective measure, the Ataxia Instrumented Measure-Spoon (AIM-S), which consists of a spoon equipped with a BioKin wireless motion capture device, and algorithms that analyse these signals, to measure ataxia of the upper limb during the pre-oral phase of eating. The aim of this study was to evaluate the AIM-S as a sensitive and functionally relevant clinical outcome for use in clinical trials. A prospective longitudinal study evaluated the capacity of the AIM-S to detect change in upper limb function over 48 weeks. Friedreich ataxia clinical severity, performance on the Nine-Hole Peg Test and Box and Block Test and responses to a purpose-designed questionnaire regarding acceptability of AIM-S were recorded. Forty individuals with Friedreich ataxia and 20 control participants completed the baseline assessment. Thirty individuals with Friedreich ataxia completed the second assessment. The sensitivity of the AIM-S to detect deterioration in upper limb function was greater than other measures. Patient-reported outcomes indicated the AIM-S reflected a daily activity and was more enjoyable to complete than other assessments. The AIM-S is a more accurate, less variable measure of upper limb function in Friedreich ataxia than existing measures. The AIM-S is perceived by individuals with Friedreich ataxia to be related to everyday life and will permit individuals who are non-ambulant to be included in future clinical trials.

A comprehensive scheme for the objective upper body assessments of subjects with cerebellar ataxia.

BACKGROUND: Cerebellar ataxia refers to the disturbance in movement resulting from cerebellar dysfunction. It manifests as inaccurate movements with delayed onset and overshoot, especially when movements are repetitive or rhythmic. Identification of ataxia is integral to the diagnosis and assessment of severity, and is important in monitoring progression and improvement. Ataxia is identified and assessed by clinicians observing subjects perform standardised movement tasks that emphasise ataxic movements. Our aim in this paper was to use data recorded from motion sensors worn while subjects performed these tasks, in order to make an objective assessment of ataxia that accurately modelled the clinical assessment. METHODS: Inertial measurement units and a Kinect© system were used to record motion data while control and ataxic subjects performed four instrumented version of upper extremities tests, i.e. finger chase test (FCT), finger tapping test (FTT), finger to nose test (FNT) and dysdiadochokinesia test (DDKT). Kinematic features were extracted from this data and correlated with clinical ratings of severity of ataxia using the Scale for the Assessment and Rating of Ataxia (SARA). These features were refined using Feed Backward feature Elimination (the best performing method of four). Using several different learning models, including Linear Discrimination, Quadratic Discrimination Analysis, Support Vector Machine and K-Nearest Neighbour these extracted features were used to accurately discriminate between ataxics and control subjects. Leave-One-Out cross validation estimated the generalised performance of the diagnostic model as well as the severity predicting regression model. RESULTS: The selected model accurately ([Formula: see text]) predicted the clinical scores for ataxia and correlated well with clinical scores of the severity of ataxia ([Formula: see text], [Formula: see text]). The severity estimation was also considered in a 4-level scale to provide a rating that is familiar to the current clinically-used rating of upper limb impairments. The combination of FCT and FTT performed as well as all four test combined in predicting the presence and severity of ataxia. CONCLUSION: Individual bedside tests can be emulated using features derived from sensors worn while bedside tests of cerebellar ataxia were being performed. Each test emphasises different aspects of stability, timing, accuracy and rhythmicity of movements. Using the current models it is possible to model the clinician in identifying ataxia and assessing severity but also to identify those test which provide the optimum set of data. Trial registration Human Research and Ethics Committee, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia (HREC Reference Number: 11/994H/16).

Enhancing survival motor neuron expression extends lifespan and attenuates neurodegeneration in mutant TDP-43 mice.

Defects in the RNA-binding proteins survival motor neuron (SMN) and TAR DNA-binding protein 43 (TDP-43) cause progressive motor neuron degeneration in spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS), respectively. While low levels of SMN protein in motor neurons result in SMA, recent studies implicate abnormal SMN levels and function in ALS pathogenesis. Here, we determine that SMN protein is upregulated early and progressively in spinal and cortical motor neurons of male transgenic mutant TDP-43A315T mice. Cytoplasmic SMN aggregates that contain TDP-43 and HuR were identified in motor neurons of TDP-43A315T mice, consistent with the incorporation of SMN into stress granules. To test the impact of augmenting SMN levels in TDP-43 proteinopathy, we demonstrate that neuronal overexpression of human SMN in TDP-43A315T mice delayed symptom onset and prolonged survival. SMN upregulation also countered motor neuron degeneration, attenuated activation of astrocytes and microglia and restored AMP kinase activation in spinal cords of TDP-43A315T mice. We also reveal that expression of another factor conferring motor neuron vulnerability, androgen receptor (AR), is reduced in spinal cords of male TDP-43A315T mice. These results establish that SMN overexpression in motor neurons slows disease onset and outcome by ameliorating pathological signs in this model of mutant TDP-43-mediated ALS. Further approaches to augment SMN levels using pharmacological or gene therapy agents may therefore be warranted in ALS. Our data also reinforce a novel potential link between ALS and spinal bulbar muscular atrophy (SBMA), another motor neurodegenerative disease mediated by reduced AR function in motor neurons.

Can Valproic Acid Regulate Neurogenesis from Nestin+ Cells in the Adult Midbrain?

Degeneration of dopamine (DA) neurons in the substantia nigra pars compacta (SNc) causes the motor symptoms (e.g. tremor, muscle rigidity, bradykinesia, postural instability) of Parkinson's disease (PD). It is generally agreed that replacing these neurons will provide better motor symptom relief and fewer side effects than current pharmacotherapies. One potential approach to this is up-regulating endogenous DA neurogenesis in SNc. In the present study, we conducted bioinformatics analyses to identify signalling pathways that control expression of Pax6 and Msx1 genes, which have been identified as potentially important neurogenic regulators in the adult midbrain. From this Valproic acid (VPA) was identified as a regulator of these pathways, and we tested VPA for its ability to regulate midbrain neurogenesis in adult mice. VPA was infused directly into the midbrain of adult NesCreERT2/R26eYFP mice using osmotic pumps attached to implanted cannula. These mice enable permanent eYFP+ labelling of adult Nestin-expressing neural precursor cells and their progeny/ontogeny. VPA did not affect the number of eYFP+ midbrain cells, but significantly reduced the number of Pax6+, Pax6+/NeuN+, eYFP+/NeuN+ and eYFP-/NeuN+ cells. However, this reduction in NeuN expression was probably via VPA's Histone de-acetylase inhibitory properties rather than reduced neuronal differentiation by eYFP + cells. We conclude that Pax6 and Msx1 are not viable targets for regulating neurogenesis in the adult midbrain.

Mutant SOD1 inhibits ER-Golgi transport in amyotrophic lateral sclerosis.

Cu/Zn-superoxide dismutase is misfolded in familial and sporadic amyotrophic lateral sclerosis, but it is not clear how this triggers endoplasmic reticulum (ER) stress or other pathogenic processes. Here, we demonstrate that mutant SOD1 (mSOD1) is predominantly found in the cytoplasm in neuronal cells. Furthermore, we show that mSOD1 inhibits secretory protein transport from the ER to Golgi apparatus. ER-Golgi transport is linked to ER stress, Golgi fragmentation and axonal transport and we also show that inhibition of ER-Golgi trafficking preceded ER stress, Golgi fragmentation, protein aggregation and apoptosis in cells expressing mSOD1. Restoration of ER-Golgi transport by over-expression of coatomer coat protein II subunit Sar1 protected against inclusion formation and apoptosis, thus linking dysfunction in ER-Golgi transport to cellular pathology. These findings thus link several cellular events in amyotrophic lateral sclerosis into a single mechanism occurring early in mSOD1 expressing cells.

3D Electrospun scaffolds promote a cytotrophic phenotype of cultured primary astrocytes.

Astrocytes are a target for regenerative neurobiology because in brain injury their phenotype arbitrates brain integrity, neuronal death and subsequent repair and reconstruction. We explored the ability of 3D scaffolds to direct astrocytes into phenotypes with the potential to support neuronal survival. Poly-ε-caprolactone scaffolds were electrospun with random and aligned fibre orientations on which murine astrocytes were sub-cultured and analysed at 4 and 12 DIV. Astrocytes survived, proliferated and migrated into scaffolds adopting 3D morphologies, mimicking in vivo stellated phenotypes. Cells on random poly-ε-caprolactone scaffolds grew as circular colonies extending processes deep within sub-micron fibres, whereas astrocytes on aligned scaffolds exhibited rectangular colonies with processes following not only the direction of fibre alignment but also penetrating the scaffold. Cell viability was maintained over 12 DIV, and cytochemistry for F-/G-actin showed fewer stress fibres on bioscaffolds relative to 2D astrocytes. Reduced cytoskeletal stress was confirmed by the decreased expression of glial fibrillary acidic protein. PCR demonstrated up-regulation of genes (excitatory amino acid transporter 2, brain-derived neurotrophic factor and anti-oxidant) reflecting healthy biologies of mature astrocytes in our extended culture protocol. This study illustrates the therapeutic potential of bioengineering strategies using 3D electrospun scaffolds which direct astrocytes into phenotypes supporting brain repair. Astrocytes exist in phenotypes with pro-survival and destructive components, and their biology can be modulated by changing phenotype. Our findings demonstrate murine astrocytes adopt a healthy phenotype when cultured in 3D. Astrocytes proliferate and extend into poly-ε-caprolactone scaffolds displaying 3D stellated morphologies with reduced GFAP expression and actin stress fibres, plus a cytotrophic gene profile. Bioengineered 3D scaffolds have potential to direct inflammation to aid regenerative neurobiology.

Antibodies to surface dopamine-2 receptor in autoimmune movement and psychiatric disorders.

Recent reports of autoantibodies that bind to neuronal surface receptors or synaptic proteins have defined treatable forms of autoimmune encephalitis. Despite these developments, many cases of encephalitis remain unexplained. We have previously described a basal ganglia encephalitis with dominant movement and psychiatric disease, and proposed an autoimmune aetiology. Given the role of dopamine and dopamine receptors in the control of movement and behaviour, we hypothesized that patients with basal ganglia encephalitis and other putative autoimmune basal ganglia disorders harboured serum autoantibodies against important dopamine surface proteins. Basal ganglia encephalitis sera immunolabelled live surface cultured neurons that have high expression of dopamine surface proteins. To detect autoantibodies, we performed flow cytometry cell-based assays using human embryonic kidney cells to express surface antigens. Twelve of 17 children (aged 0.4-15 years, nine males) with basal ganglia encephalitis had elevated immunoglobulin G to extracellular dopamine-2 receptor, compared with 0/67 controls. Immunofluorescence on wild-type mouse brain showed that basal ganglia encephalitis sera immunolabelled microtubule-associated protein 2-positive neurons in striatum and also in cultured striatal neurons, whereas the immunolabelling was significantly decreased in dopamine-2 receptor knock-out brains. Immunocytochemistry confirmed that immunoreactivity localized to the surface of dopamine-2 receptor-transfected cells. Immunoabsorption of basal ganglia encephalitis sera on dopamine-2 receptor-transfected human embryonic kidney cells decreased immunolabelling of dopamine-2 receptor-transfected human embryonic kidney cells, neurons and wild-type mouse brain. Using a similar flow cytometry cell-based assay, we found no elevated immunoglobulin G binding to dopamine 1, 3 or 5 receptor, dopamine transporter or N-methyl-d-aspartate receptor. The 12 dopamine-2 receptor antibody-positive patients with encephalitis had movement disorders characterized by parkinsonism, dystonia and chorea. In addition, the patients had psychiatric disturbance with emotional lability, attention deficit and psychosis. Brain magnetic resonance imaging showed lesions localized to the basal ganglia in 50% of the patients. Elevated dopamine-2 receptor immunoglobulin G was also found in 10/30 patients with Sydenham's chorea, 0/22 patients with paediatric autoimmune neuropsychiatric disorders associated with streptococcal infection and 4/44 patients with Tourette's syndrome. No dopamine-1 receptor immunoglobulin G was detected in any disease or control groups. We conclude that assessment of dopamine-2 receptor antibodies can help define autoimmune movement and psychiatric disorders.

A Bayesian Network Approach for Friedreich Ataxia Severity Classification using Probability Modelling.

Friedreich ataxia (FRDA) requires an objective measure of severity to overcome the shortcoming of clinical scales when applied to trials for treatments. This is hindered due to the rarity of the disease resulting in small datasets. Further, the published quantitative measures for ataxia do not incorporate or underutilise expert knowledge. Bayesian Networks (BNs) provide a structure to adopt both subjective and objective measures to give a severity value while addressing these issues. The BN presented in this paper uses a hybrid learning approach, which utilises both subjective clinical assessments as well as instrumented measurements of disordered upper body movement of individuals with FRDA. The final model's estimates gave a 0.93 Pearson correlation with low error, 9.42 root mean square error and 7.17 mean absolute error. Predicting the clinical scales gave 94% accuracy for Upright Stability and Lower Limb Coordination and 67% accuracy for Functional Staging, Upper Limb Coordination and Activities of Daily Living.Clinical relevance- Due to the nature of rare diseases conventional machine learning is difficult. Most clinical trials only generate small datasets. This approach allows the combination of expert knowledge with instrumented measures to develop a clinical decision support system for the prediction of severity.

Neuronal activity regulates expression of tyrosine hydroxylase in adult mouse substantia nigra pars compacta neurons.

Striatal delivery of dopamine (DA) by midbrain substantia nigra pars compacta (SNc) neurons is vital for motor control and its depletion causes the motor symptoms of Parkinson's disease. While membrane potential changes or neuronal activity regulates tyrosine hydroxylase (TH, the rate limiting enzyme in catecholamine synthesis) expression in other catecholaminergic cells, it is not known whether the same occurs in adult SNc neurons. We administered drugs known to alter neuronal activity to mouse SNc DAergic neurons in various experimental preparations and measured changes in their TH expression. In cultured midbrain neurons, blockade of action potentials with 1 µM tetrodotoxin decreased TH expression beginning around 20 h later (as measured in real time by green fluorescent protein (GFP) expression driven off TH promoter activity). By contrast, partial blockade of small-conductance, Ca(2+) -activated potassium channels with 300 nM apamin increased TH mRNA and protein between 12 and 24 h later in slices of adult midbrain. Two-week infusions of 300 nM apamin directly to the adult mouse midbrain in vivo also increased TH expression in SNc neurons, measured immunohistochemically. Paradoxically, the number of TH immunoreactive (TH+) SNc neurons decreased in these animals. Similar in vivo infusions of drugs affecting other ion-channels and receptors (L-type voltage-activated Ca(2+) channels, GABA(A) receptors, high K(+) , DA receptors) also increased or decreased cellular TH immunoreactivity but decreased or increased, respectively, the number of TH+ cells in SNc. We conclude that in adult SNc neurons: (i) TH expression is activity-dependent and begins to change ∼20 h following sustained changes in neuronal activity; (ii) ion-channels and receptors mediating cell-autonomous activity or synaptic input are equally potent in altering TH expression; and (iii) activity-dependent changes in TH expression are balanced by opposing changes in the number of TH+ SNc cells.

Protein disulphide isomerase protects against protein aggregation and is S-nitrosylated in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis is a rapidly progressing fatal neurodegenerative disease characterized by the presence of protein inclusions within affected motor neurons. Endoplasmic reticulum stress leading to apoptosis was recently recognized to be an important process in the pathogenesis of sporadic human amyotrophic lateral sclerosis as well as in transgenic models of mutant superoxide dismutase 1-linked familial amyotrophic lateral sclerosis. Endoplasmic reticulum stress occurs early in disease, indicating a critical role in pathogenesis, and involves upregulation of an important endoplasmic reticulum chaperone, protein disulphide isomerase. We aimed to investigate the involvement of protein disulphide isomerase in endoplasmic reticulum stress induction, protein aggregation, inclusion formation and toxicity in amyotrophic lateral sclerosis. Motor neuron-like NSC-34 cell lines were transfected with superoxide dismutase 1 and protein disulphide isomerase encoding vectors and small interfering RNA, and examined by immunocytochemistry and immunoblotting. Expression of mutant superoxide dismutase 1 induced endoplasmic reticulum stress, predominantly in cells bearing mutant superoxide dismutase 1 inclusions but also in a proportion of cells expressing mutant superoxide dismutase 1 without visible inclusions. Over-expression of protein disulphide isomerase decreased mutant superoxide dismutase 1 aggregation, inclusion formation, endoplasmic reticulum stress induction and toxicity, whereas small interfering RNA targeting protein disulphide isomerase increased mutant superoxide dismutase 1 inclusion formation, indicating a protective role for protein disulphide isomerase against superoxide dismutase 1 misfolding. Aberrant modification of protein disulphide isomerase by S-nitrosylation of active site cysteine residues has previously been shown as an important process in neurodegeneration in Parkinson's and Alzheimer's disease brain tissue, but has not been described in amyotrophic lateral sclerosis. Using a biotin switch assay, we detected increased levels of S-nitrosylated protein disulphide isomerase in transgenic mutant superoxide dismutase 1 mouse and human sporadic amyotrophic lateral sclerosis spinal cord tissues. Hence, despite upregulation, protein disulphide isomerase is also functionally inactivated in amyotrophic lateral sclerosis, which may prevent its normal protective function and contribute to disease. We also found that a small molecule mimic of the protein disulphide isomerase active site, (+/-)-trans-1,2-bis(mercaptoacetamido)cyclohexane, protected against mutant superoxide dismutase 1 inclusion formation. These studies reveal that endoplasmic reticulum stress is important in the formation of mutant superoxide dismutase 1 inclusions, and protein disulphide isomerase has an important function in ameliorating mutant superoxide dismutase 1 aggregation and toxicity. Functional inhibition of protein disulphide isomerase by S-nitrosylation may contribute to pathophysiology in both mutant superoxide dismutase 1-linked disease and sporadic amyotrophic lateral sclerosis. Protein disulphide isomerase is therefore a novel potential therapeutic target in amyotrophic lateral sclerosis and (+/-)-trans-1,2-bis(mercaptoacetamido)cyclohexane and other molecular mimics of protein disulphide isomerase could be of benefit in amyotrophic lateral sclerosis and other neurodegenerative diseases related to protein misfolding.

Objective Assessment of Progression and Disease Characterization of Friedreich Ataxia via an Instrumented Drinking Cup: Preliminary Results.

The monitoring of disease progression in certain neurodegenerative conditions can significantly be quantified with the help of objective assessments. The severity assessment of diseases like Friedreich ataxia (FRDA) are usually based on different subjective measures. The ability of a participant with FRDA to perform standard neurological tests is the most common way of assessing disease progression. In this feasibility study, an Ataxia Instrumented Measurement-Cup (AIM-C) is proposed to quantify the disease progression of 10 participants (mean age 39 years, onset of disease 16.3 years) in longitudinal timepoints. The device consists of a sensing system with the provision of extracting both kinetic and kinematic information while engaging in an activity closely associated with activities of daily living (ADL). A common functional task of simulated drinking was used to capture features that possesses disease progression information as well as certain other features which intrinsically correlate with commonly used clinical scales such as the modified Friedreich Ataxia Rating Scale (mFARS), the Functional Staging of Ataxia score and the ADL scale. Frequency and time-frequency domain features allowed the longitudinal assessment of participants with FRDA. Furthermore, both kinetic and kinematic measures captured clinically relevant features and correlated 85% with clinical assessments.

Quantitative Assessment of Friedreich Ataxia via Self-Drinking Activity.

Effective monitoring of the progression of neurodegenerative conditions can be significantly improved by objective assessments. Clinical assessments of conditions such as Friedreich's Ataxia (FA), currently rely on subjective measures commonly practiced in clinics as well as the ability of the affected individual to perform conventional tests of the neurological examination. In this study, we propose an ataxia measuring device, in the form of a pressure canister capable of sensing certain kinetic and kinematic parameters of interest to quantify the impairment levels of participants particularly when engaged in an activity that is closely associated with daily living. In particular, the functional task of simulated drinking was utilised to capture characteristic features of disability manifestation in terms of diagnosis (separation of individuals with FA and controls) and severity assessment of individuals diagnosed with the debilitating condition of FA. Time and frequency domain analysis of these biomarkers enabled the classification of individuals with FA and control subjects to reach an accuracy of 98% and a correlation level reaching 96% with the clinical scores.

Elevated HDL Levels Linked to Poorer Cognitive Ability in Females With Parkinson's Disease.

INTRODUCTION: Cholesterol levels have been associated with age-related cognitive decline, however, such an association has not been comprehensively explored in people with Parkinson's disease (PD). To address this uncertainty, the current cross-sectional study examined the cholesterol profile and cognitive performance in a cohort of PD patients. METHODS: Cognitive function was evaluated using two validated assessments (ACE-R and SCOPA-COG) in 182 people with PD from the Australian Parkinson's Disease Registry. Total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and Triglyceride (TRG) levels were examined within this cohort. The influence of individual lipid subfractions on domain-specific cognitive performance was investigated using covariate-adjusted generalised linear models. RESULTS: Females with PD exhibited significantly higher lipid subfraction levels (TC, HDL, and LDL) when compared to male counterparts. While accounting for covariates, HDL levels were strongly associated with poorer performance across multiple cognitive domains in females but not males. Conversely, TC and LDL levels were not associated with cognitive status in people with PD. CONCLUSION: Higher serum HDL associates with poorer cognitive function in females with PD and presents a sex-specific biomarker for cognitive impairment in PD.

Balance Deficits due to Cerebellar Ataxia: A Machine Learning and Cloud-Based Approach.

Cerebellar ataxia (CA) refers to the disordered movement that occurs when the cerebellum is injured or affected by disease. It manifests as uncoordinated movement of the limbs, speech, and balance. This study is aimed at the formation of a simple, objective framework for the quantitative assessment of CA based on motion data. We adopted the Recurrence Quantification Analysis concept in identifying features of significance for the diagnosis. Eighty-six subjects were observed undertaking three standard neurological tests (Romberg's, Heel-shin and Truncal ataxia) to capture 213 time series inertial measurements each. The feature selection was based on engaging six different common techniques to distinguish feature subset for diagnosis and severity assessment separately. The Gaussian Naive Bayes classifier performed best in diagnosing CA with an average double cross-validation accuracy, sensitivity, and specificity of 88.24%, 85.89%, and 92.31%, respectively. Regarding severity assessment, the voting regression model exhibited a significant correlation (0.72 Pearson) with the clinical scores in the case of the Romberg's test. The Heel-shin and Truncal tests were considered for diagnosis and assessment of severity concerning subjects who were unable to stand. The underlying approach proposes a reliable, comprehensive framework for the assessment of postural stability due to cerebellar dysfunction using a single inertial measurement unit.

Differential effects of sex on longitudinal patterns of cognitive decline in Parkinson's disease.

BACKGROUND: Cognitive impairment is an important and diverse symptom of Parkinson's disease (PD). Sex is a purported risk variable for cognitive decline in PD, but has not been comprehensively investigated. OBJECTIVES: This cross-sectional and longitudinal study examined sex differences in global and domain-specific cognitive performance in a large PD cohort. METHODS: Cognitive function was evaluated using the Addenbrooke's Cognitive Examination in 392 people with PD (PwP) from the Australian Parkinson's Disease Registry. The influence of sex on domain-specific cognitive performance was investigated using covariate-corrected generalised linear models. In a repeated measures longitudinal subset of 127 PwP, linear mixed models were used to assess the impact of sex on cognition over time, while accounting for covariates. RESULTS: Cross-sectional-corrected modelling revealed that sex was significantly predictive of cognitive performance, with males performing worse than females on global cognition, and memory and fluency domains. Longitudinally, sex was significantly predictive of cognitive decline, with males exhibiting a greater reduction in global cognition and language, whereas females showed a greater decline in attention/orientation, memory and visuospatial domains, despite starting with higher baseline scores. At follow-up, a significantly higher proportion of males than females fulfilled criteria for mild cognitive impairment or PD dementia. CONCLUSIONS: Sex was revealed as a significant determinant of overall cognitive performance as well as specific cognitive domains, with a differential pattern of decline in male and female participants. Such sex-specific findings appear to explain some of the heterogeneity observed in PD, warranting further investigation of mechanisms underlying this sexual dimorphism.

Retrograde axonal tracing using manganese enhanced magnetic resonance imaging.

Manganese-enhanced magnetic resonance imaging (MEMRI) was used to investigate retrograde axonal tracing in the rat sciatic nerve model to assess its potential to examine peripheral nerve injury. The right sciatic nerve was exposed and crushed. After each recovery period, the distal part of the right sciatic nerve was injected with manganese (400 mM, 15 microl). After allowing 3 days for manganese transport the animals were subsequently scanned to visualize the sciatic nerve and its corresponding spinal cord and dorsal root ganglia with T1-weighted MRI. Thirty-four animals were randomly divided into 4 experimental groups according to their recovery period post-crush injury: 3 days (n=6), 2 weeks (n=6), 4 weeks (n=6) and 12 weeks (n=6); and two control groups: a non-crushed group (n=6) and a nerve cut group (n=4). In the no-injury group, the right sciatic nerve tract including its corresponding spinal cord and dorsal root ganglia showed significant T1 signal enhancement. In the animals with crush injury, the MR signal intensity was significantly reduced proximal to the injured site but gradually reappeared with increasing recovery period. The signal intensity of the sciatic tract was compared to the results of behavioral functional testing, retrograde axonal tracing with neural tracer fluorogold and histomorphometric analysis of the distal nerve. Significant correlations were observed between the MR signal intensity and the behavioral functional test (r=0.50, p<0.05), and the retrograde axonal tracing (r=0.88; p<0.05). Retrograde neuronal tract tracing with MEMRI can be used for the assessment of peripheral nerve damage and regeneration.

Dopamine D2 receptor knockout mice develop features of Parkinson disease.

OBJECTIVE: This study questions whether increased dopamine (DA) turnover in nigral neurons leads to formation of Lewy bodies (LBs), the characteristic alpha-synuclein-containing cytoplasmic inclusion of Parkinson disease (PD). METHODS: Mice with targeted deletion of the dopamine D(2) receptor gene (D(2)R[-/-]) have higher striatal and nigral dopamine turnover and elevated oxidative stress. These mice were examined for evidence of histological, biochemical, and gene expression changes consistent with a synucleinopathy. RESULTS: LB-like cytoplasmic inclusions containing alpha-synuclein and ubiquitin were present in substantia nigra pars compacta (SNpc) neurons of older D(2)R(-/-) mice, and were also occasionally seen in aged wild-type mice. These inclusions displaced the nucleus of affected cells and were eosinophilic. Diffuse cytosolic alpha-synuclein immunoreactivity in SNpc neurons increased with age in both wild-type and D(2)R(-/-) mice, most likely because of redistribution of alpha-synuclein from striatal terminals to SNpc cell bodies. Gene and protein expression studies indicated endoplasmic reticulum (ER) stress and changes in trafficking and autophagic pathways in D(2)R(-/-) SNpc. These changes were accompanied by a loss of DA terminals in the dorsal striatum, although there was no evidence of progressive cell death in the SNpc. INTERPRETATION: Increased sprouting and DA turnover, as observed in PD and D(2)R(-/-) mice, augments LB-like inclusions and axonal degeneration of dopaminergic neurons. These changes are associated with ER stress and autophagy.

A blinded, controlled trial of objective measurement in Parkinson's disease.

Medical conditions with effective therapies are usually managed with objective measurement and therapeutic targets. Parkinson's disease has effective therapies, but continuous objective measurement has only recently become available. This blinded, controlled study examined whether management of Parkinson's disease was improved when clinical assessment and therapeutic decisions were aided by objective measurement. The primary endpoint was improvement in the Movement Disorder Society-United Parkinson's Disease Rating Scale's (MDS-UPDRS) Total Score. In one arm, objective measurement assisted doctors to alter therapy over successive visits until objective measurement scores were in target. Patients in the other arm were conventionally assessed and therapies were changed until judged optimal. There were 75 subjects in the objective measurement arm and 79 in the arm with conventional assessment and treatment. There were statistically significant improvements in the moderate clinically meaningful range in the MDS-UPDRS Total, III, IV scales in the arm using objective measurement, but not in the conventionally treated arm. These findings show that global motor and non-motor disability is improved when management of Parkinson's disease is assisted by objective measurement.