Biomedical subjects
Publications and source records attributed to J Sousa.
Paraganglioma of the filum terminale is rare. The authors report a case of paraganglioma of the filum terminale presenting with paraparesis on a background of spastic quadriparesis. The clinical presentation, radiological findings and current literature are presented.
Spontaneous intracerebral haematoma (ICH) is an extremely unusual complication following the evacuation of a chronic subdural haematoma (CSDH). Good outcome is expected after the drainage of the CSDH and neurological deterioration is a cause for serious concern. Authors report three cases of spontaneous ICH away from the site of surgery following evacuation of a CSDH with a review of literature. Changes in cortical blood flow following decompression of a long standing CSDH may be responsible for the ICH.
Sigmoid sinus thrombosis in children following a closed head injury is rare. The authors report such a case with the clinical presentation, radiological findings and current literature.
Pellets comprising chitosan, cellulose microcrystalline, povidone, filler excipient and diclofenac sodium as model drug were prepared by extrusion-spheronisation. The effects of chitosan load (zero, 0%, low, 4% and high, 16% levels), type of filler (lactose, tribasic calcium phosphate and beta-cyclodextrin) and composition of the binding liquid (ethanol/water mixtures 20 and 50%) on physical characteristics of pellets were evaluated. A three-factor factorial design was employed in the study. Analysis of variance (ANOVA) indicated that single factors had significant effect on the physical characteristics of the pellets. The type of filler followed by polymer load markedly affected the density. The type of binding liquid had negligible effect on the shape and surface roughness of the pellets. Increase in the chitosan load resulted in pellets of lower porosity values. This could be attributed to the binding capacity of chitosan and povidone leading to more compacted structures. Chitosan load and type of filler had significant influence on the surface roughness. The surface of pellets became rougher as the chitosan load increased, however, there was no significant difference between zero and low contents of chitosan. Pellets prepared using tribasic calcium phosphate showed a smoother surface when compared with formulations including lactose or beta-cyclodextrin. Chitosan was useful to provide pellets of acceptable physical characteristics when employing an alcohol/water mixture 50% (v/v) as binding liquid for the extrusion-spheronisation process.
We report two cases of patients with bilateral 'mirror image' or 'kissing' aneurysms at the distal anterior cerebral arteries who presented with subarachnoid haemorrhage and frontal intracerebral haematoma.
Patients with severe head injury with bilateral dilated unreactive pupils are considered to have a grave prognosis. Hence proper planning and aggressive management becomes mandatory for achieving good results. We present the outcome of consecutive 166 patients with severe head injury, admitted between January 1996 and December 2000 and analysed retrospectively. All the patients had an initial GCS of 8 or less and post resuscitation bilateral dilated unreactive pupils. Our aim was to analyze the long term outcome in these patients and identify the other significant prognostic factors. Of the 166 patients, 42 (25.30%) had a functional outcome (good recovery in 10.24%, moderate disability in 15.06%), and 124 (74.69%) had a poor outcome (death in 58.43% and severe disability in 16.26% of cases). There were 45 patients with polytrauma and 24 of these patients (53.33%) succumbed to the injuries. Obliteration of the basal cisterns and contusion were the common CT scan findings. Factors adversely affecting the survival included age of the patient, polytrauma with shock, initial GCS of 3 or 4, and compression of the basal cisterns on the initial CT scans. At follow up, most of the patients with a functional outcome showed a significant improvement in their motor function but continued to have neuro-behavioral and cognitive deficits.
The negative surface charge of many cellular membranes concentrates protons and rarefies superoxide in their vicinity. It was speculated that the low pH near membranes should facilitate superoxide protonation, thereby concentrating hydroperoxyl radical in this region. This process would exacerbate both lipid peroxidation and the transfer of oxidative damage between cellular compartments, as hydroperoxyl is a good initiator of lipid peroxidation and permeates lipid bilayers. Surface-charge-enhancement of hydroperoxyl production in mitochondria--which are main intracellular sources of superoxide--should be particularly relevant. Using a simple model of superoxide metabolism in the mitochondrial matrix, we calculated the gradients of pH, superoxide, and hydroperoxyl, and assessed the previous hypothesis in the light of available experimental data. The following predictions ensued: (i) Near the mitochondrial inner membrane, gradients of superoxide concentration with amplitude up to 36% of the maximal concentration, and pH gradients of up to 0.19 units between membrane and bulk. (ii) These electrostatically induced gradients die out within approximately 4 nm of the membrane. (iii) At high (hundreds of nanometres) inter-cristae separations, owing to enzyme-catalyzed dismutation of superoxide, both superoxide and hydroperoxyl become rarefied towards the midpoint between cristae. (iv) Surface charge should neither enhance superoxide protonation nor concentrate hydroperoxyl near biological membranes.
Adenoid cystic carcinoma is a rare neoplasm arising from the exocrine glands such as salivary glands, lachrymal glands, upper respiratory tract, breast or uterine cervix. Intracranial involvement is commonly from direct skull base involvement, although metastasis may rarely be seen. The predisposition of the adenoid cystic carcinoma for perineural and perivascular invasion is the prime reason for the locally invasive character of the tumour, often extending into the cranium via foramina at the skull base. The authors report a case of primary orbito-cranial extradural adenoid cystic carcinoma and cranial metastasis away from the primary site. This patient initially had a local excision, and later an exenteration of the right eye followed by with radiotherapy. Within months she presented with an extradural cranial recurrence, distant torcular metastasis without any neurological deficit. Craniotomy and radical excision was undertaken as these tumours have slow growth rates, and long term survival of the se patients even in the presence of local recurrence and metastasis has been well documented.
Enterogenous cysts are rare congenital lesions resulting from dysgenesis during the third embryonic week at the time of notochord development and the transitory existence of the neurenteric canal. Enterogenous cysts are usually lined by mucus secreting epithelium resembling that of the gastrointestinal tract. The inclusion of the endodermal elements in the spinal canal may produce extradural, intradural extramedullary or intradural intramedullary cystic lesions. The endodermal inclusions producing cysts in the intracranial compartment are extremely rare, especially in the supratentorial region. Plain X-rays may show concomitant cranio-spinal anomalies. However, CT and MRI scans show better definition and characterisation. Total excision is the procedure of choice in these benign cysts with favourable long term prognosis. Approximately 100 histologically proven cases have been described, with a few exceptions, as isolated case reports the authors report a detailed analysis of the clinico-radiological aspects of a series of ten patients with cranio-spinal enterogenous cysts with a review of the literature.
Diffuse idiopathic skeletal hyperostosis (DISH) has long been regarded as a benign asymptomatic clinical entity with an innocuous clinical course. Precise information is lacking in the world literature. Authors report the results of a retrospective analysis of 74 cases of DISH. Eleven patients presented with progressive spinal cord or cauda equina compression. In nine cases ossified posterior longitudinal ligament (OPLL) and in two cases ossified ligamentum flavum (OLF) were primarily responsible. Surgically treated patients (eight) had far better outcome as compared to the patients managed conservatively, as they had refused surgery. 'DISH' is neither a benign condition, nor it always runs a innocuous clinical course. In fact, in about 15% of the cases, serious neurological manifestations occur, which may require a major neurosurgical intervention.
Metastatic parotid tumours in the skull are very rare. An interesting case of a mucoepidermoid parotid tumour metastasizing to the skull vault is described in a patient who had previously been operated for a pituitary adenoma 20 years back with no post operative radiotherapy; however, she required hormonal supplementation therapy. She underwent an operation for a parotid tumour 7 years ago and received postoperative radiotherapy for the parotid tumour away from the site of the skull metastases. No local recurrence of the parotid tumour was noted. The initial diagnosis was that of a solitary intradiploic meningioma. Interesting clinico-radiological findings are presented.
Yolk sac tumours are rare conditions among the germ cell tumours. Intracerebral germ cell tumours are exceedingly rare. A 15 year old girl presenting with a one week history of raised intracranial pressure is described. She had bilateral papilloedema and a right 6th nerve palsy. CT scan showed an intra-parenchymatous right frontal ring enhancing lesion of 2 cms diameter. The patient underwent microsurgical total excision of the tumour, followed by chemotherapy. She was asymptomatic at three years following surgery.
Salivary gland tumors are rare entities among the patients with head and neck neoplastic lesions. Between January 1987 to August 1997, 62 patients with salivary gland tumors presented to the surgical department of Goa Medical College, which is a tertiary referral center for the region. These patients were analyzed with an aim to study the clinical and histopathological correlation. While no age predisposition for the malignancy was found, the parotid gland was the most common site for both malignant & benign tumors (69.35%), and the minor glands (4.8%) the least common. Apart from the presence of facial nerve involvement, pain and rapid growth were also the indicators of malignancy. Fine needle aspiration cytology (FNAC) proved to be a reliable method for management of these tumors. All the patients underwent surgery with minimal morbidity and no mortality. There was no identifiable association between smoking, alcohol intake and the occurrence of the salivary glands tumors.
Despite the increasing knowledge on the pathways involved in TCR signal transduction and T cell activation, the molecular mechanism of TCR triggering by ligand, MHC-peptide complexes, is still elusive and controversial. The present paper addresses the controversy on the early events of TCR engagement and triggering. Mathematical modelling techniques are applied to experimental data to infer plausible molecular mechanisms of TCR triggering and down-regulation. A similar approach has been followed by Bachmann et al. (Eur. J. Immunol. 1998, 28: 2571 - 2579), who concluded that the TCR triggering requires the formation of MHC-TCR dimers or trimers. We report here the failure to generalize this conclusion to the data reported by Valitutti et al. (Nature 1995, 375: 148 - 151). We show that there are several kinetic features in these experimental curves of TCR down-regulation that cannot be explained by the simple model proposed by Bachmann et al. unless some phenomenological extensions are considered. These extensions are: (1) a ligand independent turnover of the TCR; (2) a transient accumulation of triggered TCR; (3) a high order of TCR triggering kinetics; and (4) two pools of membrane TCR in dynamic equilibrium.
Two unique cases of chronic calcified subdural hematomas are reported in children as a long-term complication of a ventriculoperitoneal shunt. Both the patients had undergone shunt procedures in infancy for congenital hydrocephalus. In one patient, the cause of the hydrocephalus was aqueduct stenosis, while in the second patient, a lumbar meningomyelocele was associated with hydrocephalus. In both these patients, a ventriculoperitoneal shunt was done in infancy. In one of them, following the shunt surgery, a bilateral subdural collection was noticed which required burr hole evacuation. Both the patients remained asymptomatic for 9 years, when they presented to our center with acute raised intracranial pressure and contralateral hemiparesis. Both the patients had a relatively short history and had altered sensorium at admission. Surprisingly, in both the patients, the CT scan showed significant mass effect producing calcified subdural hematomas. The shunt systems were found to be working well at surgery. Craniotomy and excision of the calcified subdural hematomas was undertaken. Postoperatively, the patients showed satisfactory recovery, and at discharge the patients were doing well. At the follow-up at the outpatient clinic, the patients were asymptomatic.
The Authors report a case of toxic multinodular goiter induced by longstanding administration of Amiodarone, in which the option was near total thyroidectomy for control of toxic symptoms without withdrawal of the antiarhuthmic drug. In this case, the post-operative period was complicated by compressive cervical hematoma, which was managed by performing an emergent tracheostomy.
The Authors report a case of toxic multinodular goiter induced by longstanding administration of Amiodarone, in which the option was near total thyroidectomy for control of toxic symptoms without withdrawal of the antiarhuthmic drug. In this case, the post-operative period was complicated by compressive cervical hematoma, which was managed by performing an emergent tracheostomy.