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Biomedical subjects

P Satishchandra

Publications and source records attributed to P Satishchandra.

At least 19 recordsLinked to original sources
PubMed2003

Primary auditory neuropathy - an enigma.

OBJECTIVES: To report audiological and neuroradiological findings in patients with primary auditory neuropathy (PAN) from a tertiary institution in south India. MATERIAL AND METHODS: The auditory profiles in 24 patients were analyzed along with neurological and radiological findings. RESULTS: Puretone audiometry showed varied hearing acuity and configuration. The syllable recognition score (n=15) was above 80% except in three. The dichotic digit test (n=11) showed bilateral suppression except in two who showed unilateral suppression. The auditory brainstem responses and the acoustic stapedius reflex were absent with distortion product otoacoustic emission (DPOAE) present in all. The neurological and radiological studies were normal. CONCLUSION: The audiological profile is consistent with the presence of DPOAE and absence of acoustic stapedius reflex and auditory brainstem responses. In patients with adequately preserved syllable recognition in quiet conditions, there was a significantly poor performance on dichotic digit test. As these patients had no neurological deficits and absence of specific etiological factors, we propose to use the term PAN for this entity.

Acoustic Stimulation↗
PubMed2003

Epilepsy control program in India: a district model.

Based on data originating from neuroepidemiologic studies in India, epilepsy has been identified as a public health problem. The treatment gap varies from 50 to 70% among persons with epilepsy and is compounded further by limited availability of neurologists, often working in urban metropolises, thus restricting the availability of services in a predominantly rural agrarian country. Cost-effective, sustainable epilepsy care programs are urgently required in India. To bridge this wide gap, a district model was developed with the central focus on training the district medical officers in providing epilepsy care with sensitization of state health administrators and nodal neurologists to support and sustain the program. Workshops were conducted for all three groups during the period 1999-2001, with the involvement of 21 state health administrators, 148 district medical officers, and 28 neurologists. Preliminary evaluation indicates a growing interest, enthusiastic commitment, and willingness among health professionals to expand epilepsy care to the periphery. The program revealed that it is possible to reach people with epilepsy on the premise of early diagnosis and management, need-based referral network, and a rational planning for uninterrupted availability of antiepileptic drugs along with education of families. Policy-level initiatives are required further to transform this on a wider scale and to evaluate the efficacy and effectiveness of this approach.

Delivery of Health Care↗
PubMed2003

Hot-water epilepsy.

Geographically specific epilepsy syndromes are of epidemiologic interest and may assist in understanding the pathogenic mechanism of epilepsy in general. Some may have a genetic basis with added environmental influence. Among these epilepsy syndromes in India is an interesting type of reflex seizure known as hot-water epilepsy (HWE) and single small computed tomography (CT)-enhancing lesions (SSCTLs).

Baths↗
PubMed2003

Research in epilepsy: development priorities for developing nations.

PURPOSE: To identify research priorities in epilepsy for developing nations. METHODS: A panel discussion with audience participation at the Indo-U.K. Workshop on Epilepsy. This included short presentations by panelists, the presentation of a research proposal, and debate on research priorities. RESULTS: The need to focus on primary-care populations; to use a multi-centre random block design; to incorporate rural areas and a service component; to study incidence, natural history, and aetiology; to focus on problems, such as cysticercosis, and to adopt a comprehensive public health-centred approach in doing so; to study disorders of local interest, such as hot water epilepsy; to pilot both pharmacological and nonpharmacological interventions; to incorporate comprehensive measures of cognition, behaviour, and psychosocial outcome in all studies; and to examine the role of novel diagnostic tools (imaging for example) and therapy (surgery for example) on cost were all outlined as priority areas. DISCUSSION: There is a felt need for greater and better-quality research output from the developing world. The development of uniform research protocols, the twinning of developed and developing nations for research, and training of developing nations' personnel are likely to increase research output in the years that come.

Developing Countries↗
PubMed2003

Low prevalence of progressive multifocal leukoencephalopathy in India and Africa: is there a biological explanation?

Infection with human immunodeficiency virus (HIV) clade C virus is the most common form of HIV infection in the world. It largely infects populations in Africa and Asia and not much is known about the neurological complications associated with the virus. Cases of progressive multifocal leukoencephalopathy (PML) have been rarely reported in the literature in the acquired immunodeficiency syndrome (AIDS) or non-AIDS populations from these regions. In this article, the authors present three recently diagnosed patients with AIDS and PML from one neurological center in India, review the diagnostic challenges faced, and speculate on the possible biological reasons, including viral strain differences as well as HIV and JC virus interactions, that may account for the low incidence.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Brain biopsy in Creutzfeldt-Jakob disease: evolution of pathological changes by prion protein immunohistochemistry.

The formation of protease-resistant prion protein (PrPsc) is considered to be an early event in the pathogenesis of Creutzfeldt-Jakob disease (CJD) and hence its demonstration in brain biopsies by immunohistochemistry is considered diagnostic. We analysed eight brain biopsies from the frontal cortex collected from different parts of India from cases diagnosed as CJD on clinical and pathological grounds for the expression of prion protein (PrP). The duration of illness in these cases varied from 2 months to 1 year. Immunohistochemistry was carried out on paraffin sections using two different clones (KG9 and 3F4) of monoclonal antibodies to PrP. Although all eight cases showed classical features of spongiform encephalopathy of varying severity, only five of the eight cases revealed PrP(sc) in the brain tissue. The immunolabelling was focal and all areas with spongiform change were not labelled. A temporal evolution in the staining pattern was evident - particulate diffuse labelling (synaptic type) in early stages (2 months), perivacuolar deposits in intermediate stages (5-6 months), and dense plaques in late stages (12 months).

Adult↗
PubMed2002

Cryptococcal choroid plexitis as a mass lesion: MR imaging and histopathologic correlation.

Cryptococcosis is a relatively common mycotic infection of the CNS caused by a ubiquitous saprophytic fungus. We present an unusual case of CNS cryptococcosis in an immunocompetent patient. Florid choroid plexitis resulted in the formation of intraventricular enhancing mass lesions that filled the ventricles and were hyperintense to associated periventricular edema on T2-weighted MR images. We also noted lesions corresponding to microcystic, dilated Virchow-Robin spaces in the basal ganglia that were characteristic of cryptococcal infection.

Basal Ganglia↗
PubMed2000

Visual pathway abnormalities Wilson's disease: an electrophysiological study using electroretinography and visual evoked potentials.

The pathogenesis of the pattern reversal visual evoked potential (PRVEP) abnormalities in patients with Wilson's disease (WD) has not been investigated earlier. Since electroretinography (ERG) assesses the functional integrity of the retina, it was used along with PRVEP to localize the abnormalities in PRVEP in Wilson's patients. Ten newly diagnosed Wilson's disease patients underwent PRVEP and flash ERG soon after the diagnosis was established. The PRVEP latencies were prolonged in comparison with the controls (P<0.001). Photopic and scotopic A waves and oscillatory potentials were prolonged (P<0. 02) with reduction in amplitudes of photopic A and B waves (P<0.001). Six of these patients were subjected to repeat PRVEP and flash ERG after the clinical improvement with specific therapy. Comparison of the pre and post-treatment visual electrophysiological studies revealed significant reduction in latencies of PRVEP and flash ERG A wave (P<0.05) with increase in amplitudes of P100 of PRVEP (P<0.05), A and B waves of flash ERG (P<0.01). These findings confirm the reported PRVEP changes in WD and in addition demonstrate the reversibility of the retinal dysfunction which partially contributes to the PRVEP abnormalities. To the best of our knowledge this is the first study of ERG in patients with Wilson's disease in the literature. Further, there have been no earlier reports in the literature evaluating the effect of specific treatment on the PRVEP and ERG in Wilson's disease.

Adolescent↗
PubMed2000

HIV antibody profiles in serum and CSF of patients with neurological disease can serve as predictors of outcome.

The serum and CSF antibody profiles were investigated in 100 patients with HIV in relation to the type and severity of neurological disease. Among them, 87 were positive for anti-HIV antibodies in the CSF. In 30 of 87 patients detailed analysis by western blot could be performed. In 20 of 30 the profiles were dissimilar, with more of bands being found in the serum than in the CSF. The correlation of western blot profiles to the clinical outcome indicated that the number of anti-HIV antibody bands as well as the index in the CSF of fatal cases were significantly less compared with non-fatal cases (p=0.019 and p=0.039 respectively).

Adolescent↗
PubMed2000

Profile of neurologic disorders associated with HIV/AIDS from Bangalore, south India (1989-96).

One hundred patients (95 males, 5 females, mean age at presentation 31.6 +/- 9.4 yr) with various neurological disorders associated with HIV infection during 1989-1996 were evaluated at NIMHANS, Bangalore. Eighty patients belonged to group I associated with opportunistic neuroinfections and 20 to group II--non infectious neurological disorders. Cryptococcal meningitis either alone (n = 31) or associated with tuberculous meningitis (n = 6) was the most common (46.3%) followed by neurotuberculosis either alone (n = 24) or with cerebral toxoplasmosis (n = 4) accounting for 35 per cent. Other opportunistic neuroinfections included cerebral toxoplasmosis, herpes zoster, fulminant pyogenic meningitis and neurosyphilis. Clinical characteristics, diagnostic clues, their laboratory and radiological profiles and problems encountered in diagnosis and management of these opportunistic infections are highlighted. In group II (19 males and one female; mean age of 32.6 +/- 9.4 yr), two patients had cortical dementia, three acute brain stem involvement, two epilepsy and one had features suggestive of progressive multifocal leukoencephalopathy. Two patients of group I during follow up developed cortical dementia. Six had peripheral nervous system involvement similar to Guillain-Barre syndrome. Sixty six patients (63 of group I and 3 of group II) progressed to AIDS, 33 patients from group I and one patient from group II succumbed to the disease. With the rapid increase in the incidence of HIV/AIDS and an increase in the neurological manifestations of HIV/AIDS it is important to recognise the magnitude of the problem for health planning in India.

AIDS-Related Opportunistic Infections↗
PubMed1998

Mutations in a gene encoding a novel protein tyrosine phosphatase cause progressive myoclonus epilepsy.

Lafora's disease (LD; OMIM 254780) is an autosomal recessive form of progressive myoclonus epilepsy characterized by seizures and cumulative neurological deterioration. Onset occurs during late childhood and usually results in death within ten years of the first symptoms. With few exceptions, patients follow a homogeneous clinical course despite the existence of genetic heterogeneity. Biopsy of various tissues, including brain, revealed characteristic polyglucosan inclusions called Lafora bodies, which suggested LD might be a generalized storage disease. Using a positional cloning approach, we have identified at chromosome 6q24 a novel gene, EPM2A, that encodes a protein with consensus amino acid sequence indicative of a protein tyrosine phosphatase (PTP). mRNA transcripts representing alternatively spliced forms of EPM2A were found in every tissue examined, including brain. Six distinct DNA sequence variations in EPM2A in nine families, and one homozygous microdeletion in another family, have been found to cosegregate with LD. These mutations are predicted to cause deleterious effects in the putative protein product, named laforin, resulting in LD.

Alternative Splicing↗
PubMed1998

Relationship of rectal & hippocampal temperature profiles to seizure activity in rats prone & resistant to hot water induced epilepsy.

The present study evaluates the relationship of seizure proneness, to core body and brain temperature following hot water stimulation with water of 55 degrees C in freely ambulant rats. The rectal and hippocampal temperatures were recorded in 40 rats with bathing that included the head, while 10 other rats had similar thermal stimulation, but of the body alone. Bipolar stainless steel electrodes were stereotactically implanted into the dorsal hippocampal regions which served the dual purpose of recording the seizure discharges as well as regional brain temperature. It was observed that in the seizure prone (SP) rats, the mean rate of rise in rectal temperature was 1.5 degrees C/min, whereas in the seizure resistant (SR) animals it was 0.78 degree C/ min. However, there was no noticeable difference in the rate of rise in brain temperatures between the SP and SR groups, the rate of rise being 0.3 degree C/min. In the rats subjected to hot water bath over the body (excluding the head), there was no seizure activity. Further, there was no change in the brain temperature recorded in these rats, despite the rate of rise in rectal temperature being similar to that in the SP rats. These observations indicate that two thermoregulatory factors operate in seizure proneness-viz., a rapid rise in core body temperature; and a rise in local brain temperature. Both should coexist in order to elicit a hyperthermic seizure in rats.

Animals↗
PubMed1996

Hyperthermic seizures: an animal model for hot-water epilepsy.

Freely ambulant wistar adult rats of both sexes when exposed to a hot water jet on the head (50 degrees C - 55 degrees C) for a period of 8-10 minutes, manifested seizure activity similar to the ones noted in 'hot-water epilepsy' (HWE) in humans. Depth electrode recording from the hippocampus revealed seizure discharges during the ictus lasting from 34 seconds to three minutes, followed by low voltage indeterminate activity and a quiescent resting phase. Seizure initiation was noted to be critically dependent on the rectal temperature of 41.5 degrees C and regional hippocampal temperature of 37 degrees C. There appeared to be no clear evidence for kindling phenomenon. Intervention of hyperthermia by cooling the body after the ictus prevented subsequent occurrence of spontaneous seizures. Pathological study of the brain revealed ischaemic changes in specific topographic areas like Sommer's sector in hippocampus, layer 4 and 5 neurons of the cerebral cortex and reticular neurons in the brain stem- a pathological feature reminiscent of the human epileptic brain. Seizure initiation by hyperthermic stimulation with hot water poured over the head, the progression and the EEG recording the seizure activity in these rats appears to resemble the HWE in human subjects and could thus serve as the first animal model for this form of "reflex' epilepsy. This has given new insight into the understanding of human HWE. Our preliminary observations in humans has suggested that HWE is a type of hyperthermic seizure similar to febrile convulsion but differs from it with respect to stimulus and rate of rise in temperature in a susceptible individual.

Adult↗