RESUMO
An increasing body of experience is defining the value of the impedance bridge for the detection and diagnosis of otologic disorders. In this study the audiometric status of 1,133 ears is correlated with the tympanometric configuration and middle ear pressure. It is noted that the air-bone gap systematically increases as the middle ear pressure decreases from 0 to -400 mm Ho. Mildly negative middle ear pressure (Jerger's Type A Tympanogram) produces air-bone gaps statistically greater than at atmospheric pressure. These data demonstrate the magnitude of the adverse effect of negative middle ear pressure upon middle ear auditory function.
Assuntos
Orelha Média/fisiopatologia , Transtornos da Audição/fisiopatologia , Pressão , Audiometria , Orelha Média/patologia , Transtornos da Audição/diagnóstico , Humanos , Métodos , Estudos RetrospectivosRESUMO
The stria vascularis of young albino guinea pigs was examined by scanning electron microscopy at intervals of 30, 60, and 240 minutes after the intracardiac administration of ethacrynic acid (70 mg/kg). Results from this study showed that the appearance of large intercellular spaces in the intermediate region of the stria vascularis was due to acute separation of these cells rather than atrophy, as described by previous investigators. It was probable that these spaces were due to an accumulation of extracellular fluid. In some marginal cells, extrusions of cytoplasm into the endolymphatic space were noted in the 240-minute group of animals. The importance of these extrusions is not apparent at this time.
Assuntos
Cóclea/efeitos dos fármacos , Ácido Etacrínico/farmacologia , Animais , Cóclea/ultraestrutura , Citoplasma/efeitos dos fármacos , Citoplasma/ultraestrutura , Endolinfa/efeitos dos fármacos , Espaço Extracelular/efeitos dos fármacos , Cobaias , Microscopia Eletrônica de Varredura , Fatores de TempoRESUMO
We have investigated the histochemical changes in the succinodehydrogenase (SDH) and adenosine triphosphatase (ATPase) enzyme systems of the guinea pig cochlea at 30, 60, and 240 minutes following the intracardiac injection of ethacrynic acid. In control animals, there is intense SDH activity in the stria vascularis, spiral prominence, and hair cells. At all periods after ethacrynic acid injection, there was decreased activity of SDH in the outer hair cells in the basal turn. The activity of SDH in the stria vascularis and spiral prominence was equally as intense as in control animals at all periods, however. Strong ATPase activity in control animals was demonstrated by dark-brown precipitations in the external sulcus cells, stria vascularis, and hair cells. The ATPase activity was decreased at 60 minutes after ethacrynic acid injection only in the stria vascularis. The importance of these results is discussed.
Assuntos
Adenosina Trifosfatases/metabolismo , Cóclea/efeitos dos fármacos , Ácido Etacrínico/farmacologia , Succinato Desidrogenase/metabolismo , Animais , Cóclea/enzimologia , Cóclea/patologia , Metabolismo Energético , Cobaias , Histocitoquímica , Órgão Espiral/efeitos dos fármacos , Órgão Espiral/enzimologia , Fatores de TempoRESUMO
In the eleven years since the introduction of the first commercially available scanning electron microscope, a number of otologic studies have made use of this new technique. However, the literature contains only one report of scanning ultrastructure of the endolymphatic surface of the stria vascularis. We have studied the stria vascularis with a technique allowing examination of the mid-modiolar cut surface as well as the endolymphatic surface.