RESUMO
This study was designed to aid experimental otologic studies of the rat middle ear. The topographic anatomy of the albino rat middle ear is described. A set of microphotographs with matching illustrations presents the structural details at several surgical exposures. Anatomic differences between the rat, guinea pig, and cat are noted.
Assuntos
Orelha Média/anatomia & histologia , Anatomia Comparada , Animais , Artéria Carótida Interna/anatomia & histologia , Artéria Carótida Interna/cirurgia , Gatos , Cóclea/anatomia & histologia , Cóclea/cirurgia , Modelos Animais de Doenças , Meato Acústico Externo/anatomia & histologia , Meato Acústico Externo/inervação , Meato Acústico Externo/cirurgia , Ossículos da Orelha/anatomia & histologia , Ossículos da Orelha/cirurgia , Orelha Média/irrigação sanguínea , Orelha Média/inervação , Orelha Média/cirurgia , Nervo Facial/anatomia & histologia , Nervo Facial/cirurgia , Feminino , Cobaias , Humanos , Bigorna/anatomia & histologia , Bigorna/cirurgia , Masculino , Martelo/anatomia & histologia , Martelo/cirurgia , Ilustração Médica , Microcirurgia , Fotomicrografia , Ratos , Ratos Sprague-Dawley , Estribo/anatomia & histologia , Estribo/irrigação sanguínea , Cirurgia do Estribo , Tensor de Tímpano/anatomia & histologia , Tensor de Tímpano/cirurgia , Membrana Timpânica/anatomia & histologia , Membrana Timpânica/cirurgiaRESUMO
Acute sudden sensorineural hearing loss has been extensively described in the literature and is a well recognized clinical entity. The exact etiology for this entity has been difficult to ascertain. Multiple etiologies have been promoted including infectious agents, vascular abnormalities, acoustic trauma, metabolic disorders, and autoimmune syndromes. In some cases, neoplasms such as acoustic neurinoma can be identified. On occasion, ototoxic medications are present in the history. Moulonguet and Gougelot have associated mitral valve prolapse, microemboli, transient hemiparesis and sudden hearing loss. This report describes a patient who had sudden sensorineural hearing loss in conjunction with unstable angina pectoris, in whom coronary bypass surgery appeared to have resulted in acute and significant hearing improvement and stabilization.
Assuntos
Angina Instável/complicações , Perda Auditiva Súbita/etiologia , Idoso , Angina Instável/cirurgia , Ponte de Artéria Coronária , Humanos , MasculinoRESUMO
Activities of the enzymes choline acetyltransferase (ChAT) and acetylcholinesterase (AChE), which metabolize the neuromuscular transmitter acetylcholine, and malate and lactate dehydrogenase (MDH and LDH), enzymes of oxidative and glycolytic energy metabolism, respectively, were measured in the middle ear muscles of the cat. For comparison, the same enzyme activities were measured in extraocular muscle tissue and in three hindlimb muscles rich in either slow oxidative (soleus), fast glycolytic (white part of vastus lateralis), or fast oxidative glycolytic (plantaris) muscle fibers. ChAT and AChE activities were much higher in middle ear muscles than in hindlimb muscles, consistent with a denser neuromuscular innervation, as in extraocular muscles. By contrast, MDH and LDH activities were remarkably low in the middle ear muscles, lower than in any of the hindlimb muscles or the extraocular muscles. Denervation of the stapedius muscle by peripheral transection of the facial nerve resulted in decreases in all four enzyme activities without associated changes in the tensor tympani. Surgical ablation of the peripheral facial nerve supply to the stapedius muscle appears to be a feasible option for producing its denervation. The results suggest some rather specialized chemical characteristics for the middle ear muscles.