Narayanappa Gayathri

Mitochondrial alterations and oxidative stress in an acute transient mouse model of muscle degeneration: Implications for muscular dystrophy and related muscle pathologies

Background: Human muscular dystrophies and inflammatory myopathies share common pathological events. Results: The cardiotoxin (CTX) model displayed acute and transient muscle degeneration and all the cellular events usually implicated in human muscle pathology. Conclusion: Mitochondrial alterations and oxidative stress significantly contribute to muscle pathogenesis. Significance: The CTX model is valuable in understanding the mechanistic and therapeutic paradigms of muscle pathology. Muscular dystrophies (MDs) and inflammatory myopathies (IMs) are debilitating skeletal muscle disorders characterized by common pathological events including myodegeneration and inflammation. However, an experimental model representing both muscle pathologies and displaying most of the distinctive markers has not been characterized. We investigated the cardiotoxin (CTX)-mediated transient acute mouse model of muscle degeneration and compared the cardinal features with human MDs and IMs. The CTX model displayed degeneration, apoptosis, inflammation, loss of sarcolemmal complexes, sarcolemmal disruption, and ultrastructural changes characteristic of human MDs and IMs. Cell death caused by CTX involved calcium influx and mitochondrial damage both in murine C2C12 muscle cells and in mice. Mitochondrial proteomic analysis at the initial phase of degeneration in the model detected lowered expression of 80 mitochondrial proteins including subunits of respiratory complexes, ATP machinery, fatty acid metabolism, and Krebs cycle, which further decreased in expression during the peak degenerative phase. The mass spectrometry (MS) data were supported by enzyme assays, Western blot, and histochemistry. The CTX model also displayed markers of oxidative stress and a lowered glutathione reduced/oxidized ratio (GSH/GSSG) similar to MDs, human myopathies, and neurogenic atrophies. MS analysis identified 6 unique oxidized proteins from Duchenne muscular dystrophy samples (n = 6) (versus controls; n = 6), including two mitochondrial proteins. Interestingly, these mitochondrial proteins were down-regulated in the CTX model thereby linking oxidative stress and mitochondrial dysfunction. We conclude that mitochondrial alterations and oxidative damage significantly contribute to CTX-mediated muscle pathology with implications for human muscle diseases.

Neurocytoma/rhabdomyoma (myoneurocytoma) of the cerebellum

Abstract An unusual case of cerebellar neurocytoma with rhabdomyomatous differentiation in a 6-year-old boy is reported. Immunocytochemical and ultrastructural features of the tumour were studied. Abortive synapse formation, the presence of clear vesicles and synaptophysin immunoreactivity of the tumour cells indicated its intermediate neuronal differentiation, while the presence of myoblasts and myotubes and immunolabelling by desmin confirmed the rhabdomyomatous differentiation. In addition, the mesenchymal cells variably expressed neurofilament protein and glial fibrillary acidic protein, suggesting inductive interaction between the neuroectodermal and ectomesenchymal elements and persistence of the pleuripotential nature of the cells along the rhombic area of the brain stem.

Disabilities in children with Duchenne muscular dystrophy: a profile.

Proper assessment of disabilities is essential for rehabilitation of patients with Duchenne muscular dystrophy. The aim of this study was to identify and quantify the disabilities in children with Duchenne muscular dystrophy and correlate them with impairment. Thirty-one patients with Duchenne muscular dystrophy of age four years and above were studied. The motor functions were evaluated using total motor score, upper and lower extremity function grades and timed function tests. Disability was quantified with Barthel index. The mean scores of motor scales were: total motor score -52 +/- 7.8, total functional grade -4.4 +/- 1.9 and timed function score -12.5 +/- 5.8. Barthel index scores ranged from 45-95 with a mean of 70.8 +/- 12.7. Motor scales correlated with each other and with Barthel index. Thirty children had disabilities in multiple spheres of life, which were significantly influenced by the motor power. Barthel index was useful in identifying and quantifying specific areas of disabilities in these children. Evaluation of disabilities using specific measures may be crucial for planning comprehensive management.

Progressive myoclonic epilepsy: A clinical, electrophysiological and pathological study from South India

Progressive myoclonic epilepsy (PME) is a syndrome complex encompassing different diagnostic entities and often cause problems in diagnosis. We describe the clinical, electrophysiological and pathological features of 97 patients with the diagnosis of PME evaluated over 25 years. Case records of confirmed patients of Neuronal ceroid lipofuscinosis (NCL = 40), Lafora body disease (LBD = 38), Myoclonic epilepsy with ragged red fibers (MERRF = 10), and probable Unverricht-Lundberg disease (ULD = 9) were reviewed. The mean age at onset in patients with NCL (n = 40) was 5.9+/-9.1 years (M:F:: 28:12). Subtypes of NCL were: late infantile (n = 19), infantile (n = 8), juvenile (n = 11) and adult (n = 2) NCL. EEG (n = 37) showed varying degree of diffuse slowing of background activity in 94.6% and epileptiform discharges in 81.1% of patients. Slow frequency photic stimulation evoked photo-convulsive response in 5 patients only. Giant SSEP was demonstrated in 7 and VEP study revealed a prolonged P100 (2) and absent waveform (7). Electrophysiological features of neuropathy were present in 3 patients. Presence of PAS and Luxol Fast Blue (LFB) positive, auto fluorescent (AF) ceroid material in brain tissue (n = 12) and electron microscopy of brain (n = 5), skin (n = 28) and muscle (n = 1) samples showing curvilinear and lamellar bodies established the diagnosis. Patients of LBD (mean age of onset at 14.4+/-3.9 years, M:F:: 24:14) with triad of PME symptoms were evaluated. EEG (n = 37) showed variable slowing of background activity in 94.6% and epileptiform discharges in 97.4%. Photosensitivity with fast frequency was observed only in 5 patients. CT (n = 32) and MRI (n = 4) revealed diffuse cortical atrophy. Giant SSEP was demonstrated in 24 patients of LBD while VEP study revealed a prolonged P100 (4) and absent waveform (8). Electrophysiological features of neuropathy were present in one patient. Diagnosis was established by the presence of PAS positive diastase resistant, Lugols Iodine labeled inclusions in sweat glands of axillary skin (n = 35), brain (n = 2) and liver (n = 1). Ten patients with MERRF (mean age at onset: 14.6+/-5.8 years; M: F:: 3:2) had triad of PME symptoms. Muscle biopsy revealed oxidative reaction product and classical ragged red fibers. In nine patients of PME without cognitive decline, probable diagnosis of ULD (mean age at onset: 13.8+/-9.5 years) was considered after biopsy of skin and/or muscle excluded other forms of PMEs. Neuronal ceroid lipofuscinosis and Lafora body diseases were the common causes of PME in the series from south India. This is one of the largest series from the Indian subcontinent to the best of our knowledge. Photosensitivity is notably less common in LBD/NCL in this series distinctly different from those reported in the literature. Further exploration is required to determine whether different genotype is responsible. Morphological changes were helpful in diagnosis and could be confirmed by biopsy of peripheral tissues like skin and muscle in majority (60%). Electron microscopy was helpful in the diagnosis NCL and MERRF.

Clinical, Electrophysiological, Imaging, and Ultrastructural Description in 68 Patients With Neuronal Ceroid Lipofuscinoses and Its Subtypes

PURPOSE We evaluated the clinical, electrophysiological, imaging, and ultrastructural features of neuronal ceroid lipofuscinoses and its subtypes. METHODS The clinical, electrophysiological, imaging, histopathological, and ultrastructural features of 68 (age at onset: 4.3 ± 5.4 years) neuronal ceroid lipofuscinoses and its subtypes (infantile neuronal ceroid lipofuscinoses [9], late infantile neuronal ceroid lipofuscinoses [34], juvenile neuronal ceroid lipofuscinoses [23], and adult neuronal ceroid lipofuscinoses [2] were evaluated. Skin (n = 56), brain (n = 12), muscle (n = 4) and nerve (n = 1) biopsies confirmed the diagnosis. RESULTS Clinical manifestations were milestone regression (93%), involuntary movements (92%), seizures (89%), myoclonus (79%), and visual impairment (68%). Response to anticonvulsants was unsatisfactory. Electroencephalography (n = 59) was abnormal in 90%: background slowing (90%); epileptiform discharges (71%), and photoparoxysmal response (4/21). Visual-evoked (n = 33) and somatosensory evoked (n = 40) potentials were abnormal in 62% and 63% of patients. Cranial computed tomography (n = 33) showed diffuse cerebral (61%) and cerebellar (27%) atrophy. Magnetic resonance imaging was abnormal in all 43 patients who were scanned: diffuse atrophy (100%), cerebellar atrophy (40%), leukoencephalopathy (65%), and thalamic T2 W hypointensity (33%). Dermal inclusions such as curvilinear inclusions were the most common abnormality: late infantile neuronal ceroid lipofuscinoses (97%), juvenile neuronal ceroid lipofuscinoses (100%), and infantile neuronal ceroid lipofuscinoses (88%). Additional fingerprint inclusions were noted: juvenile neuronal ceroid lipofuscinoses (43%), late infantile neuronal ceroid lipofuscinoses (15%), and infantile neuronal ceroid lipofuscinoses (13%). Granular osmiophilic deposits were noted in 50% of infantile neuronal ceroid lipofuscinoses. In 75% of patients, there was good correlation between the clinical subtype and ultrastructural inclusion pattern. In 27% of neuronal ceroid lipofuscinoses, multiple inclusions were noted. CONCLUSIONS The diagnosis of neuronal ceroid lipofuscinoses should be considered in individuals with characteristic clinical presentations and characteristic ultrastructural dermal inclusions. Three fourths showed morphological correlation of the inclusions with neuronal ceroid lipofuscinoses subtype.

Acute thyrotoxic neuropathy--Basedow's paraplegia revisited.

A forty seven year old woman with previously undetected goitre, developed thyroid storm in the immediate postoperative period. Forty eight hours after undergoing nephrolithotomy for renal calculus, she was noted to have flaccid areflexic quadriparesis, most marked in the lower limbs. Electrophysiologic studies revealed evidence of an asymmetric, mixed axonal and demyelinating, motor-sensory peripheral neuropathy. Ultrastructure of the sural nerve showed predominant abnormalities in the mitochondria and cytoskeletal elements compatible with thyrotoxicosis. Treatment of thyrotoxicosis coincided with recovery of symptoms. We believe that thyrotoxicosis precipitated an acute polyneuropathy the ultrastructure of which is being described for the first time.

Dysferlinopathy: A clinical and histopathological study of 28 patients from India

BACKGROUND Miyoshi myopathy (MM) and limb girdle muscular dystrophy (LGMD2B) are distinct clinical entities because different muscle groups are involved at the onset. We describe the clinical features in 28 patients with dysferlin deficiency confirmed by muscle immunohistochemistry (IHC). SETTINGS AND DESIGN A case series from a tertiary national referral center for neurological disorders. MATERIALS AND METHODS Patients with classical phenotype of MM and LGMD2B underwent a thorough phenotypic characterization followed by muscle histopathological study including IHC for dysferlin deficiency. RESULTS There were 28 patients (20 men and eight women) presenting with manifestations of distal myopathy or LGMD2B and had absence of dysferlin staining on IHC. Patients presented predominantly with distal myopathy of Miyoshi type (MM) or proximal LGMD type and were diagnosed to have dysferlinopathy on IHC. Two patients had the proximodistal form and two had onset as tibial muscular dystrophy. The main clinical features in these patients were onset in late adolescence or early adulthood (mean age of onset for MM was 22.0 +/- 6.7 years and for LGMD2B 19.4 +/- 5.1 years). There was early and predominant involvement of the posterior compartment muscles of the leg or proximal pelvic girdle muscles, dystrophic features with necrotic regeneration pattern without vacuoles on muscle biopsy and markedly elevated serum creatine kinase values with mean of 10033.8 +/- 9283 IU/l (range 402-27460). Consanguinity was reported in 46.4%. The mean duration of illness was 6.4 +/- 4.2 years. Dysferlinopathies formed nearly one-fourth of our patients with LGMD. CONCLUSION In our experience dysferlinopathies was not an uncommon form of LGMD.

Magnetic resonance imaging correlates of genetically characterized patients with mitochondrial disorders: A study from south India

BACKGROUND Large studies analyzing magnetic resonance imaging correlates in different genotypes of mitochondrial disorders are far and few. This study sought to analyze the pattern of magnetic resonance imaging findings in a cohort of genetically characterized patients with mitochondrial disorders. METHODS The study cohort included 33 patients (age range 18 months-50 years, M:F - 0.9:1) with definite mitochondrial disorders seen over a period of 8 yrs. (2006-2013). Their MR imaging findings were analyzed retrospectively. RESULTS The patients were classified into three groups according to the genotype, Mitochondrial point mutations and deletions (n=21), SURF1 mutations (n=7) and POLG1 (n=5). The major findings included cerebellar atrophy (51.4%), cerebral atrophy (24.2%), signal changes in basal ganglia (45.7%), brainstem (34.2%) & white matter (18.1%) and stroke like lesions (25.7%). Spinal cord imaging showed signal changes in 4/6 patients. Analysis of the special sequences revealed, basal ganglia mineralization (7/22), lactate peak on magnetic resonance spectrometry (10/15), and diffusion restriction (6/22). Follow-up images in six patients showed that the findings are dynamic. Comparison of the magnetic resonance imaging findings in the three groups showed that cerebral atrophy and cerebellar atrophy, cortical signal changes and basal ganglia mineralization were seen mostly in patients with mitochondrial mutation. Brainstem signal changes with or without striatal lesions were characteristically noted in SURF1 group. There was no consistent imaging pattern in POLG1 group. CONCLUSION Magnetic resonance imaging findings in mitochondrial disorders are heterogeneous. Definite differences were noted in the frequency of anatomical involvement in the three groups. Familiarity with the imaging findings in different genotypes of mitochondrial disorders along with careful analysis of the family history, clinical presentation, biochemical findings, histochemical and structural analysis will help the physician for targeted metabolic and genetic testing.

Bilateral hypertrophic olivary nucleus degeneration on magnetic resonance imaging in children with Leigh and Leigh-like syndrome

OBJECTIVE Bilateral hypertrophic olivary degeneration on brain MRI has been reported in a few metabolic, genetic and neurodegenerative disorders, including mitochondrial disorders. In this report, we sought to analyse whether bilateral symmetrical inferior olivary nucleus hypertrophy is specifically associated with mitochondrial disorders in children. METHODS This retrospective study included 125 children (mean age, 7.6 ± 5 years; male:female, 2.6:1) diagnosed with various metabolic and genetic disorders during 2005-2012. The routine MRI sequences (T1 weighted, T2 weighted and fluid-attenuated inversion-recovery sequences) were analysed for the presence of bilateral symmetrical olivary hypertrophy and central tegmental tract or dentate nuclei signal changes. The other imaging findings and the final diagnoses were noted. RESULTS The cohort included patients with Leigh and Leigh-like syndrome (n = 25), other mitochondrial diseases (n = 25), Wilson disease (n = 40), Type 1 glutaric aciduria (n = 14), maple syrup urine disease (n = 13), giant axonal neuropathy (n = 5) and L-2 hydroxy glutaric aciduria (n = 3). Bilateral inferior olivary nucleus hypertrophy was noted in 10 patients, all of whom belonged to the Leigh and Leigh-like syndrome group. CONCLUSION Bilateral hypertrophic olivary degeneration on MRI is relatively often, but not routinely, seen in children with Leigh and Leigh-like syndrome. Early detection of this finding by radiologists and physicians may facilitate targeted metabolic testing in these children. ADVANCES IN KNOWLEDGE This article highlights the occurrence of bilateral hypertrophic olivary nucleus degeneration on MRI in children with Leigh and Leigh-like syndrome, compared with other metabolic disorders.

Duchenne muscular dystrophy: A clinical, histopathological and genetic study at a neurology tertiary care center in southern India

BACKGROUND Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy that affects young boys and the dystrophin gene on the X chromosome has been found to be associated with the disorder. MATERIALS AND METHODS In this prospective study, 112 clinically diagnosed DMD patients had muscle biopsy and were tested for exon deletions. Genotyping was also carried out at STR44, STR45, STR49 and STR 50 markers in 15 families. RESULTS Of the 112 clinically suspected DMD patients, the diagnosis of DMD was confirmed by histopathology and/or genetics in 101 patients. The mean age of onset was 3.1+/-1.44 years (1-6 years) and the mean age at presentation was 8.0+/-3.1 years (1.1-18.0 years). Delayed motor milestones were present in 63 (62.3%) patients. The mean creatine kinase value was 11822.64+/-8206.90 U/L (1240-57,700). Eighty-four patients had muscle biopsy and immunohistochemistry was done in 60 muscle samples, all of which demonstrated absence of dystrophin staining. Of the 60 dystrophin-negative cases, 73% showed deletion of at least one exon. Single exon deletion was found in 20.4%. Distal hotspot Exons 45, 47, 49 and 50 were the commonly deleted xenons and the deletion rates were 36%, 35%, 33.7% and 38.5% respectively. CONCLUSIONS In this study population in south India the deletion rate was 73% and were more frequent in the distal end exon. With the availability of genetic analysis, the first investigation of choice in DMD should be genetic studies and muscle biopsy should be considered only if the genetic tests are negative or not available.