Risk Stratification in Paragangliomas with PASS (Pheochromocytoma of the Adrenal Gland Scaled Score) and Immunohistochemical Markers.

INTRODUCTION: Paragangliomas (PGLs) are rare tumours that arise in sympathetic and parasympathetic paraganglia and are derived from neural crest cells. Presence of metastasis is the only absolute criterion for malignancy. There is no single histo-morphological feature indicating malignant potential and multiple parameters have been proposed to prognosticate the individual case. This includes studies conducted using Pheochromocytoma of the Adrenal Gland Scaled Score (PASS) and Immunohistochemical (IHC) markers. AIM: We have studied ten cases of paraganglioma and attempted to correlate the prognosis with multiple clinicopathological variables. MATERIALS AND METHODS: This study was done in a tertiary care general hospital over a period of five years. Available clinical records and histopathology slides of all patients were reviewed. Using Pheochromocytoma of the Adrenal Gland Scaled Score (PASS), we divided the cases into two groups-tumours showing high risk behaviour (PASS≥4) and tumours showing benign behaviour (PASS<4). IHC analysis was done using synaptophysin, chromogranin, S100 and Ki67. We correlated S100 immunoreactivity and Ki67 proliferative index with PASS score. Both PASS score and IHC markers were also correlated with clinical outcome. RESULTS: There were six Pheochromocytomas (PHC) and four Paragangliomas (PGL). Two paragangliomas were retroperitoneal and one each was located in ear (HNPGL) and broad ligament. PASS score was ≥4 in five cases and <4 in five cases. Out of five cases in which PASS was ≥4, three cases showed clinical evidence of malignancy and two cases were benign. All the cases in which PASS was <4 were clinically benign. S100 immunoreactivity was grade 1 in two cases, grade 2 in six cases and grade 3 in two cases. The cases in which S100 immunoreactivity was grade 1 were malignant. One case in which S100 was grade 2 was clinically malignant. Ki67 labeling index was raised (>3%) in two cases, which were malignant correlated with malignant PASS score. CONCLUSION: We conclude that the following clinicopathological parameters should be taken into account for risk assessment of malignant behaviour of paragangliomas- location, size, PASS score, S100 immunoreactivity and Ki67 labeling index.

Isolation and characterization of a novel postsynaptic/cytotoxic neurotoxin from Daboia russelli russelli venom.

A postsynaptic neurotoxin was purified from Daboia russelli russelli venom using gel filtration, ion-exchange chromatography and reverse-phase high-performance liquid chromatography. The N-terminal sequence, molecular mass and pharmacological activities of the neurotoxin/cytotoxin indicate that it is a short-chain neurotoxin like that found in Elapid venom. This is the first report on the presence of such a postsynaptic neurotoxin from D. r. russelli venom.

Levels of dopamine and noradrenaline in the developing of retina--effect of light deprivation.

The effect of light deprivation on the levels of dopamine and noradrenaline was studied in the developing rat retina. These transmitters were estimated in three groups of rats: (i) cycling light reared; (ii) dark reared since birth; and (iii) dark reared since birth, but exposed to cycling light for 1 day prior to the estimation of catecholamines. Our results show that (1) there is a progressive decrease in the levels of dopamine and noradrenaline in the cycling light and dark reared rats during postnatal development; (2) dark rearing further reduces the content of dopamine and noradrenaline; and (3) restoration of physiological (light) stimulus in the dark-reared rats during the early postnatal period results in the recovery of noradrenaline to a greater extent than that of dopamine. This study demonstrates a progressive decrease in the plasticity of dopaminergic system during retinal development, while such a decrease is not apparent in the noradrenergic system.