Expression of Protein Kinase C Isotypes in the Albino Guniea Pig Cochlea / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Protein kinase plays an important role in transmembrane signalling, which is modulated by cellular transduction by second messengers such as inositol-1, 4, 5-triphosphate (IP3), Diacylglycerol (DG), cAMP, to express biological activity by stimulation of hormones, neurotransmitters, antigens, growth factors. Protein kinase Cs participate in signal transduction of cell, secretion of neurotransmitter, regulation of ion conduction, exocytosis, gene expression and cellular proliferation. Also, it raises slow motility by Na+-H+ exchange (NHE) and Ca2+ channel in the outer hair cells. It may also be involved in mechanical transduction, cellular proliferation and reproduction in supporting cells, and in producing endolymphs using the KCNE1 and Na+/K+-ATPase in the lateral wall of cochlea. MATERIALS AND METHOD: We investigated the immunoreactivities of the PKC (alpha, beta, gamma, delta) via paraffin section and surface preparation of the cochlea of albino guinea pigs. RESULTS: PKC alpha immunoreactivities were shown in the outer and inner hair cell cytoplasm and delta was revealed in the type II fibrocytes and suprastrial cells in the basal turn of the spiral ligament. But beta, gamma were not shown. CONCLUSION: We suggest that PKC alpha may induce the slow motility and depolarization to mediate the ion conductance in the hair cells. Also, PKC delta may participate in the production of endolymph. We thus conclude that PKC alpha and delta play an important role in the cochlear signal transduction.

A Case of Optic Nerve Decompression in a Patient with Retrobulbar Neuritis Secondary to Paranasal Sinusitis / 대한이비인후과학회지

Optic neuritis (ON) is an acute or subacute inflammatory or demyelination process affecting the optic nerve. ON can be classified ophthalmologically as retrobulbar neuritis, papillitis, neuroretinitis. Retrobulbar neuritis, in which the optic disc appearance is normal, is the most common type of ON in adults. Multiple sclerosis is the most common cause of ON, but in many cases no apparent etiology is found. Paranasal sinusitis as a cause of ON is rare. Management of retrobulbar neuritis which is combined with paranasal sinusitis is controversial. Recently, we experienced a case of retrobulbar neuritis which was combined with paranasal sinusitis without orbital complication. It was treated by endoscopic sinus surgery and endoscopic optic nerve decompression in addition to intravenous antibiotics and corticosteroids. Visual acuity was improved nearly to a normal state after the treatment. The most possible pathophysiologic mechanism of retrobulbar neuritis may be the direct spread of infection of the sphenoid sinus to the optic nerve.