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Biomedical subjects

P Satishchandra

Publications and source records attributed to P Satishchandra.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1996

Neuro-epidemiological pilot survey of an urban population in a developing country. A study in Bangalore, south India.

A feasibility study was conducted in an urban population of 3,040 in Bangalore, South India, to understand the baseline characteristics, evaluate screening questionnaires, identify potential problems and determine the magnitude of the problems. The target population was selected by a random method, from four census enumeration blocks of a specific urban area. A two-phase study design was adopted consisting of screening by trained field investigators in the initial stage and clinical examination by a neurologist in the second stage. The information was collected by an interview method on a house-to-house basis. Evaluation of the screening instruments yielded high sensitivity and specificity rates, and it became clear that there is a need to reduce false-positive results in the screening questionnaire for individuals above 7 years of age. The prevalence of neurological disorders was 32.8 per 1,000 population (with a rate of 7.8/1,000 for epilepsy). It appears feasible to detect a wide range of neurological disorders using the methods described.

Adolescent↗
PubMed1996

Effect of antiepileptic drugs and calcium channel blocker on hyperthermic seizures in rats: animal model for hot water epilepsy.

Hyperthermic seizures were elicited in groups of freely ambulant rats with jets of hot water of 55 degrees C on the head for about 10 mins. Bipolar depth EEG from the hippocampus and the behavioural seizures following the stimulation were recorded. The rectal temperature (threshold) for seizure initiation was 41.5 degrees C. The seizures were predominantly clonic jerks accompanied by large spikes and slow waves lasting for 30-60s. After 3 stimulations (once a day), Phenobarbitone (Pb) 0.02 mg/g daily, Diphenylhydantoin (DPH) 0.001 mg/g, 0.005 mg/g and 0.04 mg/g. daily and Nifedipine (Nif) 0.005 mg/g twice daily were administered intraperitoneally in different rats. During the 10-days injection trials, Pb completely suppressed seizures whereas DPH and Nif did not have any effect. One of the rats with DPH showed increased epileptic activity. After a 10 day 'washout' period' Pb and DPH were interchanged and again the rats were tested for seizures on 10 days. On changing over to Pb from DPH there was complete suppression of seizures and electrical seizure discharges. Whereas those rats which earlier had no seizure activity with Pb started showing the same on changing over to DPH.

Animals↗
PubMed1995

Familial progressive myoclonus epilepsy: clinical and electrophysiologic observations.

Progressive myoclonus epilepsy (PME) is a syndrome complex encompassing different diagnostic entities. Among the 30 cases of PME studied during 1982 and 1992 at the National Institute of Mental Health and Neurosciences, Bangalore, South India, the specific diagnoses included Lafora disease (LD), neuronal ceroid lipofuscinosis (NCL). Unverricht-Lundborg disease (ULD), and myoclonus epilepsy and ragged-red fibres (MERRF). We discuss the familial nature of PME and the clinical and electrophysiological abnormalities in asymptomatic siblings. Eight cases of LD were in three different families with 3 affected siblings in two families (L1, L2) and 2 siblings in the third family (L3). Occipital seizures and behavioral changes occurred in all 3 members of L1 but were absent in the other two families. Age of onset was similar in two families (L1, 11 years; L2, 14.5 years), but not in the third. Presymptomatic EEG abnormalities were observed as long as 6 years before onset in L2. ULD occurred in 2 sisters in one family. Both had identical clinical features and normal somatosensory evoked potentials (SSEPs). The asymptomatic sister of the patient MERRF had abnormal EEG and giant SSEPs for the past 2 years. Thus, although all variations are evident in the overall clinical pattern in each of the PME, affected member of individuals families tend to be similar. Once an index case is identified, electrophysiologic tests (EEG and SSEP) may be useful in identifying other affected siblings in the presymptomatic stage.

Adolescent↗
PubMed1995

Pathological lesions in HIV positive patients.

Pathomorphological features of 10 HIV positive individuals studied at autopsy and biopsy are described. Nine patients had evidence of neuro-AIDS and eight of them succumbed to various opportunistic infections. One surviving patient underwent a diagnostic lymph node biopsy which revealed tuberculous lymphadenopathy. Cryptococcal meningitis was the commonest CNS opportunistic infection, seen in five cases, with disseminated systemic cryptococcosis in two. The other opportunistic infections included toxoplasma encephalitis in two, with acanthamoeba infection in one patient. Pulmonary tuberculosis was noted in three patients while other bacterial infections such as meningococcal meningitis, pseudomonas septicaemia were observed in three and pneumocystis carinii pneumonia in one. One seropositive individual was clinically asymptomatic but succumbed to a road traffic accident. The brain in this case showed features of HIV associated early leucoencephalopathy. Bacterial infections caused by organisms other than Mycobacterium tuberculosis associated with AIDS are often underdiagnosed and should be considered, especially in developing countries. In cases of cryptococcal and tuberculous meningitis or multiple parasitic infections, the patients should be screened for associated HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1994

Early onset Parkinson's disease: are juvenile- and young-onset different?

It is controversial if early onset Parkinson's disease (EOPD) (onset at < 41 years of age) is Parkinson's disease (PD) occurring at a younger age or a different disease. This controversy is due to some clinical and pathological differences between EOPD and PD. Within EOPD, there appear to be two groups namely: young onset Parkinson's disease (YOPD), with onset between 21 and 40 years, and juvenile parkinsonism (JP), with onset at < 20 years. The two major clinical differences between these groups are a higher familial occurrence of PD and dystonia in JP. In this study, we determine if the two groups have the classical features of PD, namely rest tremors, rigidity, bradykinesia, and postural instability, and have a meaningful response to levodopa. Furthermore, we compare their other clinical features, autonomic and cognitive functions, and levels of CSF monoamine metabolites to determine differences between these groups. We observe that all YOPD (100%) and JP (85%) patients had rest tremors. Most of these patients also had a meaningful response to levodopa (YOPD: 72%; JP: 100%). The prevalence of family history of PD was similar, whereas dystonia was more frequent in JP (43%) compared to YOPD (9%). Autonomic symptoms were twice as common in JP (42%) compared to YOPD (17%). However, bedside autonomic functions were abnormal in similar proportions and, like in PD, suggest involvement of parasympathetic nervous system. Cognitive dysfunction does occur but with no difference in severity between the two groups. The difference in number of patients between YOPD and JP groups makes statistical comparison of the occurrence of clinical features like dystonia and autonomic dysfunction difficult.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

The role of immunological & virological techniques in the diagnosis of herpes simplex encephalitis.

The efficacy of immunological and virological methods in the diagnosis of herpes simplex encephalitis (HSE) was studied in 22 patients diagnosed as HSE by clinical, radiological EEG parameters. CSF cell counts were elevated in 14 of 18 patients with a lymphocytic predominance in 13. Virus specific IgG antibody detection by ELISA in paired CSF samples was possible in 8 of 17 patients. HSV antigen could be detected by immunohistochemical methods in the cells of the CSF and/or brain tissue in 7 of 9 patients. In four of them antemortem diagnosis was possible facilitating prompt specific antiviral therapy. Virus isolation was possible in 2 of 8 patients, one from brain biopsy tissue and the other from brain tissue obtained at autopsy. Using all the three methods, the diagnosis of HSE could be confirmed in 14 of 22 (63.6%) patients.

Adolescent↗