No abstract

A rare case of a 71 -year-old man with malignant oncocytoma is presented. The tumour was found in the left parotid region with enlarged lymph nodes in the neck. The resected parotid mass consisted of three discrete nodules, each histologically characterized by a uniform proliferation of oncocytic tumour cells. The patient underwent repeated operations for recurrences and metastases, and eventually died of acute pneumonia 18 months after the first admission. Metastases to the lymph nodes, ribs, spine and liver had been clinically pointed out. Immunohistochemically, the tumour cells were positive for a-1-antitrypsin, a-1-antichymotrypsin, lactoferrin, secretory component and carcinoembryonic antigen (CEA), while they were negative for S-100 protein and HHF35 (muscle specific actin). Ultrastructural pictures disclosed numerous mitochondria in the cytoplasm of the tumour cells, revealing neither myofibrils nor secretory granules. These findings therefore support the concept that this tumour is of a glandular epithelial origin.

No abstract

Potassium canrenoate (PC) is a diuretic with antialdosterone action, reducing the reabsorption of sodium in the efferent renal tubules. This drug has been reported to damage only the marginal cells of the stria vascularis in the cochlea. The perilymphatic space of the guinea pig cochlea was perfused with an artificial perilymph containing 5 x 10(-3) M potassium canrenoate. Following the onset of perfusion, the endocochlear dc potential (EP) gradually declined to around 10 mV but did not become negative even when the perfusion was continued. A similar decrease in EP was observed in kanamycin-deafened guinea pigs. When the respirator was turned off and perfusion discontinued, a large negative EP appeared during 5 min of anoxia in normal guinea pigs but not in the kanamycin-deafened guinea pigs. The decreased EP recovered to preanoxic level after resumption of ventilation. The cochlear microphonics (CM) also gradually declined in parallel with the EP. The summating potential (SP) showed only a minor change. The potassium ion activity in the endolymph decreased slightly but the sodium ion activity remained unchanged during perfusion. These findings suggest that the main target of the PC is the cells of the stria vascularis.

No abstract