Clinical Motor Neuron Disease, Nerve Electrophysiology And Basic Research

Part1. A study on the clinical features, diagnosis, treatment and prognosis of motor neuron diseasesBackground:Motor neuron diseases (MND) are neurodegenerative diseases that result in progressive loss of bulbar and limb function. The clinical features of MND are those of progressive neurological deterioration involving the corticospinal tract, brainstem and anterior horn cells of the spinal cord. There are four recognized variations in phenotype of MND:amyotrophic lateral sclerosis (ALS), progressive muscular atrophy (PMA), progressive bulbar palsy (PBP) and primary lateral sclerosis (PLS) phenotype. The pathogenesis of MND remains unclear. They are generally progressive in nature, and can cause progressive disability and death. As riluzole remains the only evidence-based disease-modifying drug for this devastating disease, management of MND is otherwise focused on symptom control and preservation of quality of life. In this study, we provide an overview of clinical features, diagnosis and management of these devastating diseases.Objectives:In this study, we provided an overview of clinical features, diagnosis and management of motor neuron disease, and also analyzed the prognosis of different phenotypes of MND.Methods:There was a survey to collect the information about MND patients. The clinical characteristics include gender, onset, occupation, disease duration, family history, past history of disease, injury, current diagnosis, misdiagnosis, status of consent, medication and other treatment of MND patients in our outpatient department from September2009to February2012were recorded and analyzed retrospectively using statistical methods. A follow-up study was proceeded each6months to calculate the mortality and survival in four subtypes of the disease.Results:A total of224patients were recruited in our study, including187ALS (83.5%),20PBP (8.9%),13PMA (5.8%) and4PLS (1.8%). The ratio of male:female in patients was 1.80:1. The mean age of onset was49.1±10.7years. The time duration between onset and diagnosis was12.1±10.2months on average.189cases (83.6%) were diagnosed in3times of consultation. The onset sites of disease were cervical myotomes (53.6%), lumbosacral myotomes (23.2%), bulbar (17.4%) and thoracic myotomes (1.3%). MND was familial in6.7%of cases. The top3occupation of MND patients were farming, forestry, animal husbandry and fishery (21.4%), transport production (13.4%) and professionals (13.0%).65cases (29.0%) had a history of smoking and60cases(26.8%) had alcoholic.24.6%of patients had a history of physical contact with poisonous substances. The consent rate was46.9%in patients and94.2%in relatives of patients.24.6%of patients had the medication of riluzole,73.7%of patients had medications of vitamins. The rate in patients that could accept percutaneous endoscopic gastrostomy, nasal feeding, noninvasive positive pressure ventilation and tracheotomy was24.1%,31.7%,29.9%and19.2%respectively. The mortalities of ALS, PBP and PMA were26.4%,43.8%and8.3%respectively.Conclusion:MND is more common in men than in women. The risk of developing MND peaks between the ages of50years and60years. The most common occupation is the farming, forestry, animal husbandry and fishery. Most of the patients are sporadic. A few cases have a history of toxic substance contact. The onset sites are most seen in cervical myotomes. ALS is the most common type of MND. The consent rate is low in patients than in relatives of patients. A low rate of patients has the medication of riluzole and the rate of accept the supportive treatment of disease is also low. The prognosis of MND is poor. Part2. A study of autonomic dysfunction and sympathetic skin response in motor neuron diseaseBackground:Motor neuron disease (MND) is a neurodegenerative disorder characterized by progressive loss of motor neurons, but it is increasingly recognized to be a more disseminated disease. It has been proved by several previous studies that the autonomic nervous system may also be involved. The autonomic dysfunction of MND may occur in multiple systems including cardiovascular system, gastrointestinal tract and gland secretion. Sympathetic skin response (SSR) is a noninvasive neurophysiology method to examine the autonomic function of patients and has been widely used in clinical studies.Objectives:The aim of our study was to investigate the symptoms of autonomic dysfunction and SSR abnormality in MND patients.Methods:Collect the clinical features of autonomic dysfunction among the patients as dullness or pruritus of the skin, parahidrosis, xerostomia, salivation, abnormal skin temperature, orthostatic hypotension, posture-related cardiac arrhythmia, mydriasis, ptosis or abnormal pupillary light reflex, diarrhea, constipation, voiding dysfunction and sexual dysfunction. SSR was performed in all the patients. The result of SSR was judged according to the normal range of our laboratory. Abnormality rate in MND patients was calculated. The relationship between clinical symptoms and SSR parameters were analyzed by statistical methods.Results:In a total of142MND patients, the incidences of symptoms of autonomic dysfunction were as follows:dullness (53.5%), pruritus of the skin (15.5%), parahidrosis (10.6%), xerostomia (9.1%), salivation (2.1%), abnormal skin temperature (14.8%), orthostatic hypotension (2.1%), posture-related cardiac arrhythmia (0.7%), diarrhea (4.2%), constipation (16.2%), voiding dysfunction (9.9%) and sexual dysfunction (1.4%).Abnormal SSR was found in51(35.9%) of the142cases,12(8.5%) in palmar and47(33.1%) in plantar. The features of abnormal SSR included delayed latency of palmar (P<0.05) and decreased amplitudes of both palmar and plantar compared with normal ranges (P<0.01respectively). The group of patients with lumbosacral onset had higher abnormal rate of SSR than those of other onset sites. There was no significant correlation between clinical symptoms and abnommal SSR parameters.Conclusion:Patients of MND can demonstrate autonomic dysfunction of skin, gland secretion, cardiovascular system and sphincters. Some patients show abnormal SSR with prolonged latency and decreased amplitude. The abnormalities of SSR are not related to clinical features of autonomic dysfunction. Patients with onset of lower limbs have a higher rate of abnormal SSR. Part3. Oxidative modification of Cu, Zn-superoxide dismutase in amyotrophic lateral sclerosisBackground:Amyotrophic lateral sclerosis (ALS) is characterized by degeneration and loss of upper and lower motor neurons, leading to paralysis and death by3-5years after diagnosis. The majority of ALS cases are sporadic (sALS), with no apparent hereditary contribution; only5%of cases are familial (fALS), with genetic mutations dominantly inherited. Disease-causing mutations in various genes have been identified; abundant among these are mutations in the gene encoding for Cu, Zn-superoxide dismutase (SOD1). It is now established that abnormally expressed SOD1acquires toxic functions. Despite multiple epidemiologic studies investigating possible correlations between environmental or genetic triggers and ALS, the etiology of the disease remains unknown. It is imperative that we at least find markers of disease for patients with ALS. Oxidative modification is an important procedure in posttranslational modifications of a protein. In previous study of our group, we observed that the mutant SOD1was not correlated with the clinical phenotypes. Thus, we hypothesize a mechanism that the abnormal expression of SOD1protein caused by oxidative modification is a factor in a series of pathogenesis process which is related to ALS.Objectives:To explore the relationship between the toxicity of SOD1and the process of oxidative modification, and to analyze whether the wild type SOD1shared a same pathway with mutant SOD1to the pathogenesis of ALS. Western Blotting was used to examine the effect of oxidative modification on the protein aggregation. We planned to compare the level of oxidative modification in fALS, sALS and normal control. If the effect of oxidative modification in mechanism of ALS could be proved, an opportunity was raised to develop biomarkers to subclassify ALS and devise SOD1-based therapies.Methods:Collect the blood samples of members of fALS families, sALS patients and gender, age matched normal healthy controls. SOD1gene mutation was screened in each member of fALS families, sALS patient and control subject. The total SOD activity of erythrocyte was examined by a reaction with xanthine oxidase. Western Blotting was used in the observation of SOD1expression and aggregation in peripheral blood mononuclear cell (PBMC) and serum, and also the analysis of redox SOD1after the treatment of iodoacetic acid (IAA) and β-mercaptoethanol. Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) combined with matrix assisted laser desorption ionization-time off light mass spectrometer (MALDI-TOF-MS) and differential proteomics were designed to search for a difference in peptide structure of SOD1between ALS patients and normal controls.Results:185sALS patients and7fALS families were recruited in this study. According to gene sequence, no SOD1gene mutation was found in these patients. The total SOD activity showed no significance between ALS patients and age-matched controls (0.158U/ml vs0.150U/ml, P>0.05).In patients without SOD1mutation, the expression of SOD1was not significantly increase or decreased compared with normal subjects (P>0.05). Redox Western Blotting demonstrated no significant differences between sALS patients without SOD1mutation and normal subjects. The study of mass spectrometry also found no evidence of abnormal oxidation of SOD1in ALS patients group.Conclusion:The total SOD activity in ALS patients without SOD1mutation is normal. The molecular weight and expression of protein are not changed in "wild type" SOD1, indicating that there might not be an aggregation. Redox Western Blotting shows no abnormal oxidation or deoxidization in this type of SOD1protein. The structure of peptides does not change without the stimulation of oxidative stress. Therefore, it can be inferred that the basic properties are not alternated in "wild type" SOD1of ALS patients. The oxidative modification may not be an initial mechanism in the pathophysiology of the disease. Further studies should focus on the susceptibility of oxidative stress and possible toxicity of this "wild type" SOD1.