Wataru Oshima

Quantitative Analysis of Kanamycin Ototoxicosis

The morphological changes after kanamycin intoxication of the inner ear, including both the cochlea and the vestibule, were quantitatively analysed by the surface preparation technique after succinic dehydrogenase staining. 75 guinea pigs were used. The outer hair cells in the basal coil and the inner hair cells in the upper coils of the cochlea were the most severely damaged, but many unusual modes of damage were also revealed. For example, the initial hair cell damage in the cochlea appeared in the upper hair cells. The clearly observed vestibular damage contradicts the general belief that kanamycin is not so toxic to the vestibular hair cells. The utricular macula and the lateral crista were most severely damaged. The delayed ototoxicity of kanamycin was observed for the first time in the vestibular hair cells.

Fibrolipoma of the parotid in a child

Fibrolipoma is a rare benign tumor found predominantly in middle and later life; it is very uncommon in children1 There are many reports in literature of resected fibrolipomas of the oral cavity.2,3 However, there are only a few reports of fibrolipoma in the parotid. This report describes a case of a S-year-old girl with fibrolipoma of the parotid gland. This is the youngest such patient to be found in the literature. lobules of yellow adipose tissue separated by white fibrous septa. No hemorrhage, necrosis, or calcification was noted. Microscopic examination of sections stained by hematoxylin and eosin showed lobules of mature adipose tissue mixed with a network of fibrous connective tissue (Fig 4). The fibrous elements contained numerous fibrocytes, suggesting the presence of mature collagen. The adipose component consisted of mature adipocytes. The histopathological features were consistent with a fibrolipoma.

A case of angiosarcoma of the nasal cavity successfully treated with recombinant interleukin-2.

Angiosarcomas very rarely arise in the nose and paranasal sinuses, with an incidence of about 4%. To our knowledge, there have been only 4 reported cases in the literature. This paper reports a case of angiosarcoma arising in the nasal cavity that decreased in size after the administration of recombinant interleukin-2 (rIL-2), with a brief review of the literature. A 55-year-old male with a chief complaint of frequent epistaxis on the left side was referred to our department for close examination on January 21, 2000. His past and family histories were unremarkable. No abnormal findings were noted in the ear, pharynx, larynx, or neck. Examination of blood coagulation was normal. Enhanced CT showed a mass lesion with an enhancement effect in the left nasal cavity. T1-weighted images of MRI also demonstrated an enhanced tumor in the left nasal cavity (Fig 1a). After septal correction surgery on April 20, 2000, a dark red tumor was found in the left nasal cavity. A biopsy specimen was taken during surgery. Pathological examination of HE-stained sections showed proliferation and irregular arrangement of vascular endothelial cells (Fig 1b and c). Immunohistochemical analyses using CD34 showed a specifically positive staining corresponding to vascular endothelial cells. We concluded that the nasal tumor was angiosarcoma. Angiography of the left carotid artery was performed on May 8, 2000. The tumor was supplied by both the anterior ethmoid artery, a branch of the internal carotid artery, and the greater palatine artery, a branch of the external carotid

Localization of triphosphoinositide in the cochlea

SummaryTriphosphoinositide (TPI) has been demonstrated to be a receptor for aminoglycosides in the cochlea and may regulate ionic permeability by its binding with Ca++. This phospholipid was localized by a protein A-gold technique in the cochlea at the electronmicroscopic level. TPI was prepared by a neomycin column and antibodies to it were raised in rabbits. The antibody used in this study reacted virtually only to TPI among the tested lipids. TPI was localized mainly at stereocilia, cuticular plates, head plates of Deiters cells, plasma membrane, and mitochondria of various cells in the organ of Corti. In the vascular stria, TPI was found mainly at the plasma membrane of basal infoldings of the marginal cells. Possible physiological and pathophysiological roles of TPI in the cochlea are briefly discussed.

Interaction of polyanion against kanamycin ototoxicity.

We studied whether interference of the electron bindings between kanamycin (KM) and the outer plasma membranes of the hair cells with polyanion such as heparin can reduce ototoxicity. In a short course experiment, KM 200 mg/kg/day was injected intramuscularly 23 times with or without 1 U or 0.5 U of heparin/g/day differently to 22 guinea pigs. The reducing effect of heparin against KM ototoxicity was significant from a comparison of the N1 threshold obtained by the cochleogram. The number of surviving outer hair cells in the heparin groups was significantly greater in the third turn than in the group given KM alone. A long course experiment in which 50 injections of KM with or without 0.5 U of heparin were given intramuscularly to 16 guinea pigs revealed from the pinna reflex, cochlear microphonics and cell counting that heparin could reduce ototoxicity slightly at an early stage or before reaching crucial accumulation.