Intracranial epidermoid--a 10-year study.

Twenty-eight cases of intracranial epidermoids were operated over a period of 10 years at the Bangur Institute of Neurology, Kolkata; 17 of them were male and 11 were female with an age range of 11 to 55 (mean 28.21) years. Their locations include--cerebellopontine angle region (n = 15), fourth ventricle (n = 6), lateral ventricle (n = 3), corpus callosum (n = 2), pineal region (n = 1) and basal cistern near temporal lobe (n = l). Hearing loss and vertigo were commonest features of cerebellopontine angle epidermoids. Fourth ventricular tumours presented with gait disturbances and cerebellar signs. Symptomatology of other lesions were varied. CT scan was diagnostic in 23 cases. Sixteen patients had ventriculomegaly and 10 of them required ventriculoperitoneal shunt. Total removal was achieved in 6, near total in 14 and partial in 8 cases. Five patients died. Postoperative complications included chemical meningitis in 7, worsening of cerebellar functions in 3 and aggravation of cranial nerve deficits in 2 patients. All of them except one case of cranial nerve deficit resolved with time. Nineteen patients were followed up over a mean duration of 5 years and 10 months. Reoperation was required in one. Rest had satisfactory outcome.

Novel putative protective antigens of Plasmodium falciparum.

In an attempt to identify putative host-protective antigens of the human malarial parasite P. falciparum, a differential immunoscreen of a cDNA expression library of the parasite was performed using malaria immune and patient sera. Eight expression clones were identified which showed no reactivity with acute patient sera but reacted extensively with malaria immune sera. Southern Blot analysis of five of these genes showed that these were coded by unique single genes, and sequence of the cDNA inserts showed that these were as yet unidentified genes of P. falciparum. The clone which was reactive to the largest number of immune sera, has been shown to be the ribosomal phosphoprotein, P0, of P. falciparum. The presence of multiple transcripts and a differential expression of the transcripts of P0 in different erythrocytic substages of the parasite was observed. An extensive characterisation using antibodies to the P0 protein has been performed. The results show that in addition to its role in the ribosomal assembly, the P0 protein is also localized on the parasite surface, and plays an important role in the red blood cell invasion. Most of the other differential cDNA clones were found to be rare transcripts, and the expression domains were not very immunogenic. PCR analysis of three of these genes demonstrated that these are conserved throughout the Plasmodium species. These protein domains, therefore, constitute potential protective target epitopes of the malarial parasite.

Percutaneous retrogasserian radiofrequency thermal rhizotomy for trigeminal neuralgia.

Forty patients suffering from intractable unilateral trigeminal neuralgia involving more than one division of the trigeminal nerve were treated by percutaneous radiofrequency thermocoagulation of the trigeminal sensory root. The aim of the operation was to relieve the pain without producing dense sensory deficit in the face. This goal was achieved by making selective lesions in the sensory root with gradually increasing temperature 60 degrees C to 90 degrees C. Three to four consecutive lesions each for 60 seconds have been found to produce excellent pain relief in 77.7% with good and fair results in the rest. The recurrence rate has been found to be 15% during 2 years of follow-up. Considerable dysaesthesia was observed in 5% of cases. Corneal anaesthesia was found in 5% cases while one patient developed neuroparalytic keratitis. Transient trigeminal motor weakness was observed in 10% of patients.