Finding new genes causing motor neuron diseases

Abstract Neurodegenerative disorders are a diverse group of disorders that affect specific subsets of neurons. Motor neuron diseases, neurodegenerative disorders of motor neurons, are seen commonly as sporadic cases and less frequently as familial disease forms. The familial forms show genetic and phenotypic heterogeneity. Clinically motor neuron diseases may be seen as rapidly progressive disorders like amyotrophic lateral sclerosis, ALS or slowly progressive disorders like hereditary motor neuropathies, HMN. The only proven causes for motor neuron diseases are gene mutations that lead to motor neuron degeneration in familial disease forms. Only some of these genes have been identified and have contributed greatly to our understanding of the neurobiology of familial and sporadic disease forms. Identification of additional disease causing genes would help enhance our knowledge of the pathophysiological mechanisms underlying all forms of motor neuron disorders, which would lead to early diagnoses, effective prophylaxis and efficient therapies for these disorders. This study aimed to find gene mutations that cause rapid and slowly progressive familial motor neuron disorders in Australian families and to determine their relevance to sporadic forms of motor neuron disease. The familial forms of ALS show reduced disease penetrance, that is, not all gene mutation carriers manifest the disease. This study examines ALS penetrance in a group of Australian families. The most frequently observed mutations in ALS families are cytosolic superoxide dismutase/SOD1 gene mutations. In a collection of ALS families in our centre, families without the common SOD1 gene mutations were genotyped for other ALS genes and loci and studied using genetic linkage and haplotype analyses. Studies in a large Australian ALS family further confirmed genetic heterogeneity in non-SOD familial ALS, all known autosomal dominant ALS genes and chromosomal loci were excluded as cause of disease in this family. Such families can be studied further to identify additional disease genes and loci mapped in other ALS families. These families represent powerful resources for identification of additional ALS genes. Identifying the pathogenic genes in families with reduced disease penetrance may be more relevant to sporadic forms of disease. dHMN is a chronic neurodegenerative disorder predominantly affecting motor neurons. In a large Australian dHMN family, all the known dHMN genes and chromosomal loci were excluded as cause of disease. A genome wide microsatellite screen was performed in this family and genetic linkage was established to a novel 12.98 Mb locus on chromosome 7q34.2-q36. Candidate genes in this large interval will be screened based on their function and expression profile. Identification of a new dHMN locus provides the basis for future identification of a novel gene involved in motor neuron degeneration. Genes in dHMN have been shown to be pathogenic in ALS and Charcot Marie Tooth syndromes. The new locus for dHMN mapped in this project would lead to identification of a novel dHMN gene, which may elucidate the pathogenesis underlying a wide range of neurodegenerative disorders

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

A Novel locus for distal motor neuron degeneration maps to chromosome 7q34-q36

The motor neuron diseases (MND) are a group of related neurodegenerative diseases that cause the relative selective progressive death of motor neurons. These diseases range from slowly progressive forms including hereditary motor neuropathy (HMN), to the rapidly progressive disorder amyotrophic lateral sclerosis (ALS). There is clinical and genetic overlap among these MNDs, implicating shared pathogenic mechanisms. We recruited a large family with a MND that was previously described as juvenile ALS and distal HMN. We identified a novel MND/HMN locus on chromosome 7q34-q36 following a genome-wide scan for linkage in this family. The disease causing mutation maps to a 26.2 cM (12.3 Mb) interval flanked by D7S2513 and D7S637 on chromosome 7q34-q36. Recombinant haplotype analysis including unaffected individuals suggests that the refined candidate interval spans 14.3 cM (6.3 Mb) flanked by D7S2511 and D7S798. One gene in the candidate interval, CDK5, was selected for immediate mutation analysis based upon its known association with an ALS-like phenotype in mice however, no mutations were identified. Identification of genes causing familial MND will lead to a greater understanding of the biological basis of both familial and sporadic motor neuron degeneration including ALS.6 page(s

An initial top-down proteomic analysis of the standard cuprizone mouse model of multiple sclerosis

An initial proteomic analysis of the cuprizone mouse model to characterise the breadth of toxicity by assessing cortex, skeletal muscle, spleen and peripheral blood mononuclear cells. Cuprizone treated vs. control mice for an initial characterisation. Select tissues from each group were pooled, analysed in triplicate using two-dimensional gel electrophoresis (2DE) and deep imaging and altered protein species identified using liquid chromatography tandem mass spectrometry (LC/MS/MS). Forty-three proteins were found to be uniquely detectable or undetectable in the cuprizone treatment group across the tissues analysed. Protein species identified in the cortex may potentially be linked to axonal damage in this model, and those in the spleen and peripheral blood mononuclear cells to the minimal peripheral immune cell infiltration into the central nervous system during cuprizone mediated demyelination. Primary oligodendrocytosis has been observed in type III lesions in multiple sclerosis. However, the underlying mechanisms are poorly understood. Cuprizone treatment results in oligodendrocyte apoptosis and secondary demyelination. This initial analysis identified proteins likely related to axonal damage; these may link primary oligodendrocytosis and secondary axonal damage. Furthermore, this appears to be the first study of the cuprizone model to also identify alterations in the proteomes of skeletal muscle, spleen and peripheral blood mononuclear cells. Notably, protein disulphide isomerase was not detected in the cuprizone cohort; its absence has been linked to reduced major histocompatibility class I assembly and reduced antigen presentation. Overall, the results suggest that, like experimental autoimmune encephalomyelitis, results from the standard cuprizone model should be carefully considered relative to clinical multiple sclerosis

Proteomics of a conundrum : thoughts on addressing the aetiology versus progression of multiple sclerosis

Currently in the field of multiple sclerosis (MS) research there is an ongoing debate concerning the cause of the disease. MS is widely considered to begin with an autoimmune dysregulation. The disease does have a prominent autoimmune component however this may be representative of a secondary effect. There is growing evidence that the disease may be initiated by an underlying degeneration of oligodendrocytes. In our viewpoint, we discuss the potential differences between the aetiology and progression of MS. For the most part, proteomic analysis has focused on the autoimmune component of the disease. We suggest that proteomic analysis should be applied to investigating oligodendrocyte degeneration. We discuss the potential of the cuprizone animal model of demyelination and its usefulness in understanding oligodendrocyte degeneration. Immune suppressive therapies are effective at reducing clinical symptoms and improving quality of life. However, a cure is still lacking and as such the disease does still progress. We suggest that if the initiating cause is poorly understood, then curing MS is unlikely

Structure, superconductivity and XPS studies of the Bi<SUB>2.1</SUB>Sr<SUB>1.93</SUB>Ca<SUB>0.97-x</SUB>Y<SUB>x</SUB>Cu<SUB>2</SUB>O<SUB>8+y</SUB> system

A systematic study of the effect of Y doping at the Ca site in the high-T<SUB>c</SUB> superconductor Bi2212 has been made. Starting with an off-stoichiometric composition Bi<SUB>2.1</SUB>Sr<SUB>1.93</SUB>(Ca<SUB>0.97-x</SUB>Y<SUB>x</SUB>)Cu<SUB>2</SUB> O<SUB>8+y</SUB> (BiY2212) by power X-ray diffraction, resisti vity, AC and DC susceptibility and XPS measurements have shown the single-phase nature for all values of x. The decrease in T<SUB>c</SUB> observed systematically by both resistivity and AC susceptibility measurements with increasing Y concentration, and the subsequent metal-semiconductor cross-over, is explained as due to the decrease in the average valence of the copper brought about by the excess charge introduced by Y. The Cu 2p core level shows that the relative intensity of the satellite, the energy separation between main line and satellite, and the binding energy of the main line vary in a systematic way. A decrease in charge-transfer energy and an increase in the hybridisation strength is predicted for higher x with the configuration interaction model. The presence of internal strain in this superconductor makes the BVS calculation not applicable

An integrated care solution for the electrocardiogram monitoring

Purpose This study has demonstrated how technology may contribute to integrated care solutions by comparing conventional ward telemetry (WT) to a wearable ECG monitor (S-Patch) to detect atrial fibrillation (AF) in patients with stroke. Design/methodology/approach 51 patients admitted for stroke workup were recruited across two major tertiary centres to compare WT monitoring for two days versus S-Patch for four days in the detection of AF. The efficacy to detect AF using both technologies was assessed via data extractions and medical officer review. A matrix was used to measure nursing/patient satisfaction and setup/resource times were assessed. Findings Patients (84-94%) and nursing staff (75-95%) preferred the S-Patch wearable technology. Non-parametric tests indicated significant time saving for removal of S-Patch versus WT [2.2 min vs 5.1 min (p = 0.00)]. Efficacy of S-Patch to detect AF following medical officer review was greater than WT, with seven patients identified with AF by S-Patch versus one using WT. The S-patch had a false positive rate of 78%. Research limitations/implications The S-Patch is sensitive in the detection of AF; however, it showed a high false-positive rate with automated reporting. This study has provided insight into the details of delivery of integrated healthcare using wearable technology. Originality/value The technology and partnership were the first-in-kind in Australia. The S-Patch had a higher detection rate of AF compared to WT which allows patients to be anti-coagulated appropriately for the prevention of further stroke. The results of this study will be ideally placed to inform future policy in integrated healthcare using new technologies

Computed tomography-guided fine needle aspiration cytology of solitary pulmonary nodules suspected to be bronchogenic carcinoma: Experience of a general hospital

<b>Background</b> : Fine needle aspiration cytology (FNAC) may be diagnostic in candidates with indeterminate solitary pulmonary nodules (SPNs) suspicious of bronchogenic carcinoma. <b>Aims</b> : The study was performed to evaluate the usefulness of computed tomography (CT)-guided FNAC in our centre. <b>Materials and Methods</b> : All the cases had a strong clinical suspicion of lung cancer, negative bronchoscopy, negative sputum cytology for malignant cells and acid fast bacilli. A thorough radiological evaluation was made to rule out primary malignancy elsewhere. <b>Results</b> : A total of 94 patients were studied in one year. May-Gr&#972;nwald-Giemsa stain was used for the smears. The cytological diagnosis was correlated with clinical-radiological follow-up and biopsy to arrive at a final diagnosis. The procedure had a high sensitivity and specificity. Chi-square test was used to calculate statistical significance. Tumor of more than three centimeter and immediate cytological assessment significantly increased the yield. Review of slides added two cases of malignancy that were missed initially. There were very few complications. <b>Conclusions</b> : CT-guided FNAC was an accurate and safe procedure for SPNs