Biomedical subjects
Publications and source records attributed to S K Shankar.
We report a patient with glioblastoma multiforme who was subsequently diagnosed to have Wilson's disease. Immunohistochemical studies of the tumor revealed high (> 60%) labeling index for p53 and Rb retinoblastoma protein. Whether this association is like the co-occurrence of retinoblastoma and Wilson's disease due to possible somatic mutation in chromosome 13 needs to be explored.
Rabies caused by fox bite is uncommon, most cases being caused by bite of rabid dogs (95%). We report a 45-year-old lady with rabies encephalomyelitis caused by bite of a rabid wild fox (Vulpes vulpes), a species prevalent in the Deccan plateaus of Central India. Though foxes are known to be susceptible to rabies, literature on the pathological changes caused by fox bite rabies in humans is scarce. Unlike the mild histological alterations described in canine rabies, a florid encephalitic process evolved in fox bite rabies, in our case, with intense microglial reaction, neuronophagia and perivascular inflammatory infiltrates despite clinical manifestation as a paralytic rabies. Immunostaining using polyclonal antibodies to the rabies viral nucleocapsid antigen and to the whole virion demonstrated high viral load within neurons with extensive spread along dendritic arborization and axonal tracts. Genomic sequence analysis demonstrated close homology with canine virus strain with only minor variations.
Cryptococcosis is increasing because of an ever rising population of immunocompromised individuals especially those with acquired immune deficiency syndrome (AIDS). Cryptococcal infection of the central nervous system (CNS) were diagnosed in 149 cases over a period of 19.5 years (January 1978-June 1998). Culture was positive in all cases except three who were already on antifungal therapy. India ink mounts of cerebrospinal fluid (CSF) revealed encapsulated cryptococci in 134, and cryptococcal antigen was detected in 111 of 114 patients tested. A comparison of laboratory and certain clinical parameters in patients with and without associated HIV infection showed that a poor CSF cell response and culture of cryptococci from extra-neural sites was more often associated with HIV infection and was statistically significant. Further, presence of concomitant infection especially tuberculosis, and mortality were higher in the HIV positive group.
BACKGROUND AND AIM: In view of paucity of comprehensive evaluation about dengue infection producing quadriplegia, we report the clinical, laboratory and neurophysiological studies in these patients. SUBJECTS AND METHODS: Seven out of 16 patients with dengue infection presented with quadriplegia and they were subjected to a detailed clinical history and examination. Diagnosis of dengue was based on characteristic clinical and positive serum IgM ELISA. Blood counts, serum chemistry, CSF analysis and nerve conduction and electromyographic (EMG) studies were performed in all. Outcome was defined at the end of 1 month into complete, partial and poor on the basis of activities of daily living RESULTS: The age of the patients ranged between 9 and 42 years and 2 were females. Fever was present in all and myalgia in 5 patients. Weakness developed within 3-5 days of illness, which was severe in 4 and moderate in 3 patients. Hypotonia and hyporeflexia were present in 5 patients. Nerve conduction and EMG studies were normal in all except one whose EMG was myopathic. Serum CPK and SGPT were raised in all and serum bilirubin in 3 patients. All the patients had coagulopathy and 6 had thrombocytopenia. Muscle biopsy in 1 patient was suggestive of myositis. Six patients improved completely and one had poor recovery who needed ventilatory support. CONCLUSION: Dengue virus infection may result in acute pure motor quadriplegia due to myositis. In an endemic area it should be considered in the differential diagnosis of acute flaccid paralysis.
In developing countries hydatidosis is both a medical and economic problem related to environmental hygiene and healthy veterinary practice. This cestode parasitic infestation, uncommonly involving the nervous system, presents with varied clinical manifestation, at times causing diagnostic dilemmas. Multiple intracranial and spinal hydatidosis is rare. A series of 29 histologically confirmed cases of hydatidosis of neuraxis (21 intracranial and 8 spinal) from South India are presented. Among the 21 cases of intracranial hydatidosis, 12 cases were in pediatric age, while only 1 spinal lesion was noted in a 5-year-old child. The clinical presentation of intracranial lesions was predominantly that of raised intracranial pressure and visual symptoms, while spinal hydatidosis manifested with severe back pain, weakness and sphincter disturbances. The cranial cysts were usually single and uniloculated (12 cases), multiple in 7 and single but multiloculated in 2. In spinal hydatidosis, the cysts are usually multiple and extradural, rare ones being intramedullary and intradural. Based on clinical features and imaging, the differential diagnosis for intracranial lesions were cystic tumors and arachnoid cyst while metastasis and tuberculosis were considered in cases of spinal hydatidosis because of vertebral bony involvement. The majority of the cysts could be surgically resected totally and some were aspirated under control suction and resected. None of the cases had anaphylactic reaction, with no significant post-operative morbidity and no mortality. One intracranial and 2 spinal lesions caused by fertile cysts recurred to undergo repeated surgery.
The changes in lactate dehydrogenase isoenzyme fractions in various tissues from human foetuses were studied at different stages of development. The isoenzyme pattern changes with the gestation period. The adult pattern is attained at birth in heart, liver, muscle and kidney. Brain shows predominance of cathodic fractions even at birth, but becomes aerobic after 6-12 months. LDH1/LDH5 ratio shows a similar trend. It appears that the adult pattern of LDH isoenzymes consists of predominantly either the faster (aerobic tissues) or slower (anaerobic tissue moving isoenzymes resulting from a gradual shift during foetal and neonatal life.
With a view to identify the relevant antigens of Cysticercus cellulosae, recognized within human central nervous system, immunocytochemical localization of antigens on the cestode larva has been carried out using cerebrospinal fluid of patients as the source of primary antibody. CSF from nine proven cases of neurocysticercosis, two cases of culture proven tuberculous meningitis and two cases of spinal disc prolapse with no other infective or neurological disorder were used in this study. The CSF from all the cases of neurocysticercosis intensely reacted with the glycocalyx over the integument of the cyst bladder wall. The other structures recognised by the CSF antibodies were cytoplasm of the tegumentary cytons, stroma and the ductular system of the bladder wall. The cells, stroma and calcareous corpuscles of the scolex reacted variably with the CSF. Tegument of the spiral canal and sucker muscles in the scolex were not immunoreactive. We strongly suggest that the glycocalyx is the most antigenic anatomical structure of the Cysticercus cellulosae and the patients develop antibodies to it.
Hemimegalencephaly (HME), a rare congenital abnormality characterized by unilateral enlargement of the cerebral hemisphere, is one of the less common causes of intractable seizures. We report a 6-month-old infant with uncontrolled seizures who was diagnosed to have a large mass lesion based on a CT scan. Postmortem examination revealed left-sided HME with pachygyria, widened cortex, indistinct grey-white junction, and distorted deep nuclear masses. Histological features included loss of cortical lamination, large atypical neurons with argyrophilic accumulations, ballooned cells, neuronal heterotopia, and astrocytosis with dystrophic calcification. The heterotopic neurons in the white matter were present in a radial pattern suggestive of aberrant neuronal migration. Several large neurons were dystrophic with cytoskeletal abnormalities like phosphorylated high molecular weight neurofilament and ubiquitin in the cytoplasm. However, typical neurofibrillary tangles with Congo red and tau positivity were not observed. Synaptophysin labelling was found to be decreased in the cortex, but some of the abnormal neurons had dense perisomatic label. The majority of the balloon cells were astrocytic in origin, being positive for glial fibrillary acidic protein and negative for the neuronal markers. Although the etiology of HME is not known, it provides an opportunity to study anomalous development of the brain and neuronal developmental abnormalities.
A patient with SSPE who had prominent diffuse white matter hypodensities on CT scan indicating central white matter demyelination and nerve conduction abnormalities suggestive of peripheral neuropathy is reported. Diagnosis was established by demonstration of elevated CSF measles antibody titers and presence of virus antigen and nucleocapsid in peripheral nerve. To our knowledge, this is the first report of demonstration of measles virus nucleocapsides and antigen in the peripheral nerve in SSPE.
Dysembryoplastic neuroepithelial tumor (DNT), a benign neoplasm, is now a well recognized clinicopathological entity. We report the second case of DNT in the cerebellum occurring in a 20-year-old male presenting with ataxia. He also had Arnold-Chiari malformation of the adult type. Histologically the tumor was a "simple" DNT having the specific "glioneuronal" element, namely oligodendrocyte-like cells (OLCs), mucoid change and floating neurons (Purkinje cells). A striking feature was the perpendicular arrangement of the neuropil columns extending from the pial surface to white matter similar to those seen in supratentorial examples. On immunstaining some of the OLCs were positive for synaptophysin and negative for glial fibrillary acidic protein (GFAP), glucocerebroside, tau and MAP-2. The neuropil was synaptophysin-positive and focally positive for MAP-2 and GFAP as well. The Purkinje cells were morphologically normal but malaligned and were positive for phosphorylated neurofilament suggesting secondary dysplastic changes. A transition of the lesion into relatively normal cerebellum preserving the folial architecture was observed. The histological and immunochemical features of the DNT in cerebellum suggests its possible origin from the pluripotential external granular layer.