Auditory function recovery following acoustic overstimulation.

OBJECTIVE: To examine electrophysiological data from auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs) in chickens following acoustic overstimulation. MATERIAL AND METHODS: A total of 15 white 15-day-old Leghorn chickens were used. The animals were anesthetized with Equithensin, and placed with their heads in a special holder. Click stimuli were generated by a Nicolet CA1000 device and ABRs were recorded subcutaneously using three stainless-steel electrodes. An ILO 92/DP analyzer was used to determine DPOAEs. The noise was generated by a Promax GB 212 device. The acoustic exposure was provoked with a 2-kHz pure tone at 120 dB SPL for 24 h. ABRs and DPOAEs were determined before and immediately post-exposure and 5, 15, 21 and 30 days after the traumatic exposure. RESULTS: In our control DPgram response, the maximum amplitudes (dB SPL) occurred at 1, 1.5, 2, 3 and 4 kHz and the minimum amplitudes at 0.7, 5 and 6 kHz. Immediately following acoustic overstimulation an amplitude loss in all frequencies was detected (p < 0.001). Five days after noise exposure only the amplitude loss at 3 kHz remained. Three waves with positive and negative peaks appeared in our control ABR recordings. An important threshold shift was detected in the ABR response immediately after acoustic overstimulation. Its complete recovery occurred 15 days after the acoustic trauma. CONCLUSION: Recovery of the DPgram response was detected 5 days after acoustic overstimulation, whereas the normal ABR threshold appeared on the 15th day.

Distortion-product otoacoustic emissions study of the noise-induced toughening effect in rats.

OBJECTIVE: To compare the toughening effects in rats induced by pure tones and a broadband noise (BBN). MATERIAL AND METHODS: Sprague-Dawley female albino rats (n = 148; 8-10 weeks old) were used. Three experimental groups were established as follows. Toughening only: 38 rats, divided into 3 subgroups, were exposed to different conditioning sounds (2 and 4 kHz and a BBN of 0.25-6 kHz, respectively) at 75-85 dB sound pressure limit (SPL) for 8 h/day for 10 days. Acoustic trauma only: 54 rats, divided into 3 subgroups, were exposed to different conditioning sounds as above for 24 h at 100-110 dB SPL. Toughening plus acoustic trauma: 56 rats, divided into 3 subgroups, were exposed to different conditioning sounds as above, followed 8 h later by traumatic exposure to the conditioning sound at 110 dB SPL for 24 h. 2f1-f2 distortion-product (DP) otoacoustic emission measurements were obtained from the right ear of each animal pre-exposure, immediately post-exposure and after 8 h of the traumatic or conditioning exposure. RESULTS: In our control DPgram response, the maximum amplitude occurred at the highest frequencies (2, 3, 4, 5 and 6 kHz). No statistical differences between the control DPgram and the DP toughening (2 and 4 kHz and BBN)responses were found. Only 2 and 4 kHz frequencies induced a protective effect against traumatic sound exposures to the same frequencies, and this finding was statistically significant. CONCLUSION: The toughening phenomenon induced using 2 and 4 kHz pure tones and BBN in rats does not modify the DPgram response. Nevertheless, only 2 and 4 kHz frequencies induce a protective effect against traumatic sound exposures to the same frequencies.

Morphometric study of the paranasal sinuses in normal and pathological conditions.

Prospective and retrospective morphometric CT (axial and coronal) research was performed with 100 healthy persons and 163 patients (145 males, 118 females, mean age 50 years, range 1-88 years). The patients were classified into the following groups: chronic sinusitis (n = 85), polyposis (n = 25), mucoceles (n = 13), benign tumors (n = 20) and malignant tumors (n = 20). After initial calibration with the scale (in cm) displayed on the CT image, each paranasal sinus was outlined following its bone inner surface. The data were processed with a high-resolution analysis system, and volumes were calculated using an integration areas rule. The ethmoid, maxillary and sphenoid sinuses exhibited an increase in volume for a period of up to 15 years, afterwards maintaining similar values. The frontal sinus grows in a monomodal pattern (peak at 30 years). The volumetric results (mean and standard deviation) in the normal adult group were as follows: maxillary sinus 13.07 cm3 (6.8), ethmoid 5.5 cm3 (2.0), sphenoid 3.5 cm3 (2.6) and frontal 3.7 cm3 (3.6). Primary frontal and maxillary sinus hypoplasia appeared in 3.9% and 1.3% of cases, respectively. The anatomic variations were as follows: concha bullosa 8.3%, Haller cells 3.2% and Onodi cells 8.3%. The sinusitis values (adults) were greater than those in the normal group: 14.4 cm3 (7.3), 6.8 cm3 (2.9), 2.9 cm3 (1.9) and 4.2 cm3 (5.2), with the exception of the sphenoid, but the difference was not statistically significant. Finally, we propose a new classification for paranasal sinus tumors (benign and malignant), volumetric T (vT), taking into account the morphometric tumoral volume and the mean volumetric value of normal sinuses.

[Middle ear physiology]. / Physiologie de l'oreille moyenne.

The middle ear forms part of the sound transformer mechanism, together with the outer ear and the conducting system of the inner ear. An intermediate sensory organ, sensitive to acoustic vibration, and linked to the inner ear, the middle ear made its appearance during the period of adaptation of marine creatures to a terrestrial habitat; its presence is therefore a phylogenetic requirement. It is classical to ascribe three functions to the middle ear: the transmission of acoustic vibrations from the tympanic membrane to the cochlea, impedance matching between the air in the external auditary meatus and the labyrinthine fluids, and protection of the inner ear by means of the acoustic reflex. If the classical mechanical explanation has been able to explain its function, the conceptualization of its physiology in terms of energy allows an even better understanding, as well as providing and explanation for the paradoxes which arise in clinical practice when the classical model is used.

[The study of ototoxicity in Gallus domesticus by recording distortion products]. / Estudio de la toxicidad auditiva en el Gallus domesticus mediante el registro de los productos de distorsión.

Distortion products (DP) were recorded and a morphological cochlear study was made of a sample of 60 ears from chickens (Gallus domesticus. Leghorn breed) and the ages of 15, 23, 29 and 60 days, after intoxication by intramuscular gentamicin injection (40 mg per kg weight and day for 8 days). Spontaneous or transitory otoacoustic emissions were not obtained in any case. DP recordings showed a 2F1-F2 response in every frequency band ranging from 0.7 to 6 KHz. The DP incidence shifted with the age of the chickens and differed significantly (p < 0.001) in the groups of 29 and 60 day-old chickens (m = 100%) and in the 29-day-old (m = 64%) and 60-day-old (m = 62%) intoxicated chickens. We found no significant differences in DP amplitude in subpopulations. In the intoxicated groups, the proximal segment of the ototic membrane disappeared in the macula lagenae and a loss of contact with the hair cells appeared. Degenerative vacuolar phenomena were observed in the support cells and cellular loss in the spiral ganglion.

A contribution to the structural pattern differences between the apical and basal spiral ganglions in mammals.

The purpose of this paper was to establish a mammalian comparative study between the neuronal spaces of the upper versus the basal cochlear turns. We studied with light microscopy i) Webster albino rat embryos at various gestational days (GD), and a postnatal (PN) series; ii) kittens 3 weeks old; iii) pigmented guinea pig embryos and also PN specimens; iv) diverse human fetuses. As from the 16th GD, the apical spiral ganglion primordium of the rat appears as a spherical cluster of cells immersed in the mesenchymal modular tissue whereas the basal spiral primordium displays a pyramidal shape with its apex towards the auditory receptor. Both ganglions keep this shape until the rat becomes adult. This structural pattern also appears in the cat, guinea pig and in human material. This morphological model enables a radial stratification of the peripheral and central auditory nerve projections. A thin uni- or bicellular connective layer covers the tympanic scala side of the apical spiral ganglion as from 8 hours after birth in the rat. No gap is detected in this layer which is: mesenchymal in the embryonic and fetal stages (rat, guinea pig, human), connective in PN rat and kitten, and osseous in PN guinea pig and in the human neonate.

[Genetic deafness and Pendred syndrome]. / Surdité génétique et syndrome de Pendred.

The authors present two cases of genetic deafness in a brother and his sister. The girl has shown to suffer from a deafness belonging to Pendred's syndrome; in this case, the development of hearing symptomatology since her puberty is presented as an aggravated crisis of deafness and tinnitus coinciding with her menstruation, what suggests a possible endolymphatic hydrops depending of hormonal factors; the lack of knowledge about the ethyopatogenic mechanisms in this field generates therapeutic difficulties hard to solve.

Morphologic and morphometric study of human spiral ganglion development.

A light microscopic study of the spiral ganglion was done in human embryos and fetuses measuring 45, 50, 60, 74, 90, 134, 270 mm crown-rump length (crl), and in a one-day-old neonate. Morphometric evaluations of i) cell and nuclear area, ii) nuclear area/cell area ratio, iii) ganglion area, iv) cell concentration/surface unit, and v) distance between the first neuron and the receptor were made, and the results statistically evaluated. In earlier stages of development, spiral ganglion primordia appeared as a cluster of neuroblasts and some schwannoblasts immersed in the mesenchymal tissue, close to the ductus cochlearis. A honeycomb pattern in the spiral ganglion neurons was observed in the basal turn of a 74 mm crl fetus. In later stages, the basal turn of a 90 mm crl fetus showed a spatial organization. Peripheral and central fibers of the acoustic nerve appeared stratified in early periods of development (45 mm crl embryo). From this stage on, both phenomena progress apicalwards until the neonatal period. A significant decrease in the nuclear area/cell area ratio was observed from the 134 mm crl fetus (17 weeks) to the neonatal stage in all turns. This led to a significant increase in cellular area from the 270 mm crl fetus (32 weeks) to the neonate, with no significant variation in nuclear area. The distance from the primordium of the organ of Corti to the spiral ganglion in the interval between 45 and 74 mm crl showed a significant increase in all turns.(ABSTRACT TRUNCATED AT 250 WORDS)

Histochemical and morphometrical ageing changes in human vocal cord muscles.

A histochemical and morphometrical study of thyroarytenoid and posterior cricoarytenoid human muscles was done in 43 human adults (38 males, 5 females) with ages ranging from 46 to 87 years. Vocal cord muscles were taken from laryngectomy specimens with carcinoma (25) and from autopsies (18), excluding those with neuromuscular diseases. In all cases the studied vocal cords were clinically and histologically normal in appearance. Only 2 patients received radiotherapy or chemotherapy. Posterior cricoarytenoid muscle was studied in 6 patients with larynx cancer. Mean diameter of thyroarytenoid muscle type I fibers (n = 128) was 38.46 microns and for type II 39.68 microns; fiber percentage values (n = 127) were 44.16% for type I and 55.84% for type II. Mean diameter (n = 6) of posterior cricoarytenoid muscle type I fibers was 42.69 microns and of type II 46.56 microns; type I fibers percentage was 66.15% and type II 33.85%. Statistical regression analysis revealed a progressive decrease in thickness of the mucosa and lamina propria in the right vocal cord along the ageing process. A low increase of endomysial tissue with a low decrease in perimysium in both vocal cords was noticed. In thyroarytenoid muscle, a low increase in type I fiber percentage and a decrease in type II fiber percentage were found. Posterior cricoarytenoid muscle showed a significant decrease in type I fiber percentage and diameter, corresponding to the same increase in variables of type II fibers.

[Benign esophagobronchial fistula in an adult]. / Fístula esofagobronquial benigna en un adulto.

The case of a senile dementia patient 86 year old, and a supposed clinical history of swallowing a foreign body is presented. After a clinical study (esophagogram, flexible and rigid esophagoscopy and bronchoscopy) and finally the autopsy of the patient, we found and idiopathic esophago-bronchial fistula.

[Correlation between audiometric and electronystagmographic results in Menière's disease]. / Correlación entre los resultados audiométricos y electronistagmográficos en la enfermedad de Ménière.

Cochlear and vestibular functions of 30 patients suffering from Méniere's disease have been analyzed through audiometric and electronystagmographic studies. Auditive thresholds in low, medium and high frequencies have been correlated with the results of the caloric and pendular tests. Statistical analysis has demonstrated that there is no significant relationship between caloric and pendular reflectivity and hearing loss in the mentioned frequencies. In conclusion, in Méniere's disease hearing losses and vestibular alterations follow a different pathologic pattern.

A microanalytical study on human auditory ossicles in normal and pathological conditions.

A microanalytical study of human auditory ossicles was performed in 11 normal adults, 13 infants, 13 foetuses, 7 middle ear cholesteatoma, 7 chronic otitis and 1 facial nerve schwannoma. Malleus and incus ossification is initiated in the foetal period, the Ca/P ratio reaching a value of 1.8-1.9 in the 29-gestation-week foetus and continues in the infant period until adult, except for the marginal area of the malleus head which appears mineralized in the infant. The normal Ca/P ratio for malleus is 2.10, and 2.19 for incus. In the stapes, mature Ca/P ratio values (2.11) appear in the footplate of the 23-gestation-weeks foetus. Stapes ossification continues in its head and crura, but never reaches malleus and incus values. We have confirmed that there is a relationship between Ca/P ratio and sulphur values in the ossification process; so when the first increases the second decreases. Finally, in our pathological material we have not found any significant alteration of Ca/P ratio, sulphur or other elements studied.

[Parotid actinomycosis. Apropos of a case]. / Actinomicosis parotidea. A propósito de un caso.

The parotid Actinomycosis is a very uncommon infectious disease. In this article one case is presented discussing several aspects of its diagnosis and treatment.

[Clinical considerations concerning a new case of laryngeal chondroma]. / Consideraciones clínicas acerca de un nuevo caso de condroma laríngo.

A new case of a chondroma of the larynx is reported discussing the diagnosis and its treatment. Also a brief review of the literature is presented. Scattered calcification observed by CT is considered as a pathognomic finding. Finally, biopsy is the only method for establishing the positive diagnosis.

Human otoconial crystal growth. An approach from morphological and morphometric data.

The otoconium genesis was evaluated by morphometric procedures using transmission and scanning electron-microscopic techniques for human fetuses of 50, 110, 134, 173, 210, 220 and 232 mm crown-rump length. Different otoconial crystalline habits were found. For the elongated otoconia (hexagonal prism) different parameters were measured: (1) the mean cleavage angle value of the terminal rhombohedron was 102 (SD 0.65), which was independent of the fetal age; (2) large and short axes show a linear growing law in function of the fetal age, and (3) the otoconial volume grows following a quadratic law. A hypothesis about the physicochemical growth conditions is postulated.

Midfacial granuloma syndrome. A clinic and pathological report on four patients.

Four cases of midfacial necrotizing lesions are reported. All patients were males with ages ranging from 25 to 76 years. The relationship between subjective symptoms and laboratory data prior to therapy (leukopenia, elevated ESR, increment of IgA and IgG), as well as between fever crisis with sweats and chills and the progression of the lesions were pathognomonic clinical signs for us. In all cases, paranasal sinus and nasopharynx were involved. Middle ear, eye and kidney involvement was present in 2 cases, and joints lesions only in one. Three patients died (2 of sepsis and one from hemorrhage) despite therapy. A pleomorphic cellular infiltrate with atypical lymphocytes and a tendency to angiocentricity was found in these cases. Such features and PAP positivity to beta and kappa chains led us to consider these lesions as an extranodal B-lymphocyte lymphoma-like. In the fourth case the histological picture was that of a necrotizing granuloma with clustered giant cells. This patient, treated only with prednisone, had a total remission of his symptomatology up to 11 years after the onset of the disease.

Ciliogenesis in human vestibular epithelia. A scanning electron microscopic study.

Ciliogenesis events in human vestibular epithelia develop as an asynchronous process between neighbouring cells, but it is a synchronous one within each sensory cell, presenting the following stages. Initially, the cilia buds appear as stubby cylinders well aligned on the cuticular plate of the presumptive sensory cell. In the next stage, ciliary growth occurs at one pole of the cuticular plate where elongation of the kinocilium and the nearby stereocilia can be observed. Posteriorly, the elongation of the kinocilium and the nearby stereocilia continues, remaining shorter than the other emerging stereocilia buds. Finally, the staircase height pattern of the mature sensory hair bundle is reached by means of a ciliary buds differential elongation.

A scanning electron microscopy study on human otoconia genesis.

The genesis of the otoconia was studied with SEM in several human fetuses. The results of the present paper together with previous reports (1, 2, 13) support the hypothesis that otoconia genesis may develop according the following stages: (1) calcification of some sensory and supporting cells; (2) extrusion of the calcified cellular material and some organic substances in "sponge-like bodies"; (3) deposition of diverse core seeds in these areas giving rise to a random calcium carbonate crystallization and incorporation of matrix organic material; (4) growth of otoconia developing linearly with a gradual change in shape from spherical to ovoid, rhombohedral, and cylindrical forms; (5) inhibition of crystal growth occurring once a critical unsaturated calcium endolymph state and an adequate size of statoconial membranous chambers are reached.

A study of the development of utricular and saccular maculae in man and in rat.

The ultrastructural development of utricular and saccular maculae in man and rat is described. In the human fetus with a crown-rump length (CRL) of 50 mm, the utricular and saccular epithelia consist of a pseudostratified layer of dark and light cells without nerve endings. In human fetuses of 110 and 220 mm CRL, as well as in 17- and 18-day-old rat embryos, it is already possible to identify sensory and supporting cells in various stages of differentiation. Nerve endings can also be found. Ciliogenesis is present in both sensory and supporting cells of the 17- and 18-day-old rat embryos. During epithelial differentiation a heavy calcium deposition occurs on vestibular cells of both man and rat. Otoconial mineralization increases gradually as epithelial maturation advances. Phagocytosis of otoconia by free macrophages occurs in 50-mm CRL human fetuses. Vestibular nerve myelination is asynchronous and is present in 110-mm CRL human fetuses and in 30-minute postpartum rats.

Early aspects of human cochlea development and tectorial membrane histogenesis.

Several human embryos and foetuses cochlea from the first half of pregnancy were studied by light, transmission and scanning electron microscopy. Cochlea development in man is the result of three coexisting processes: First, coiling and maturation of the cartilaginous otic capsule. Second, resorption of the periodic mesenchymal reticulum with the appearance of the labyrinthine fluids. Third, differentiation of the sensory epithelium. Tectorial membrane morphogenesis is closely related to the apocrine secretory activity of the greater and lesser epithelial ridges in the 50 mm c.r.l. specimen. In the 70, 110 and 120 mm c.r.l. specimens the secretory activity rests on the interdental cells of the spiral limbus, the undifferentiated cells of Corti's primordium and in the most external cells of the lesser epithelial ridge.