Bruno Sergi

Value of Fine-Needle Aspiration Cytology of Parotid Gland Masses

Objective To evaluate the usefulness and accuracy of fine‐needle aspiration cytology (FNAC) in the diagnosis of parotid gland masses.

Cisplatin ototoxicity in the guinea pig: vestibular and cochlear damage.

The aim of the present study was to investigate both vestibular and cochlear cisplatin toxicity. Twelve albino guinea pigs were divided into an experimental (n=8) and a control saline group (n=4) and were treated with cisplatin at a daily dose of 2.5 mg/kg for 6 consecutive days. Vestibular dysfunction was evaluated by computing the gain of the vestibular ocular reflex (VOR) evoked by stimulation in the horizontal (HVOR) and vertical (VVOR) planes. Changes in cochlear function were characterised as compound action potential threshold shifts. After the functional testing, tympanic bullae were removed and processed for morphological examination of the sensorineural epithelium. The onset of vestibular functional impairment was observed on the third day, although the VOR gain decrease was not significant. The impairment of the vestibular function progressed until the sixth day becoming statistically significant particularly at VVOR mid frequencies of stimulation. At these frequencies both macula and crista ampullaris functions are involved. Concomitantly a progressive auditory threshold shift was observed at all stimulus frequencies. The decline of the auditory function was statistically significant from the third day of treatment and it was more evident at high frequencies. Morphological observations showed a massive loss of outer hair cells and a degeneration of the organ of Corti in the basal/middle turns and only a slight loss of hair cells of the cristae ampullares and maculae. In conclusion, functional and morphological data provide evidence that the toxic effect of cisplatin is more pronounced in the organ of Corti than in the vestibular epithelium.

Protective effects of α-tocopherol and tiopronin against cisplatin-induced ototoxicity

Objective To investigate the possible protective effects of α-tocopherol and tiopronin against cisplatin-induced cochlear damage. Cisplatin ototoxicity and nephrotoxicity seem to result from the inhibition of cochlear antioxidant defences, causing an increase in the amount of reactive oxygen species. Antioxidants, such as α-tocopherol and tiopronin, are able to suppress lipid peroxidation, thus attenuating tissue damage. Material and Methods Hartley albino guinea pigs were used. The animals were treated for 7 consecutive days with either (I) cisplatin alone, (II) cisplatin+α-tocopherol acetate, (III) cisplatin+tiopronin, (IV) cisplatin+α-tocopherol acetate+tiopronin, (V) α-tocopherol acetate alone or (VI) tiopronin alone. Changes in cochlear function were characterized by means of compound action potential threshold shifts. After the functional testing, tympanic bullae were removed and processed for morphological examination of the sensorineural epithelium. Renal function was evaluated by measuring serum blood urea nitrogen and creatinine levels. Results Cisplatin induced progressive high-frequency hearing loss of 40–50 dB SPL. α-Tocopherol and tiopronin co-therapy significantly slowed the progression of hearing loss. Treatment with α-tocopherol acetate or tiopronin alone was less effective. Morphological observations showed an important loss of outer hair cells and degeneration of the organ of Corti in the basal and middle turns. Injection of both α-tocopherol and tiopronin reduced cochlear outer hair cell loss more than treatment with a single drug. Beneficial effects of α-tocopherol and tiopronin on cisplatin-induced nephrotoxicity were observed. Conclusion This study supports the hypothesis that α-tocopherol and tiopronin interfere with cisplatin-induced damage, and suggests that concurrent treatment with the two drugs can be useful in protecting against hearing loss.

Protective Effects of α-Tocopherol Against Gentamicin-induced Oto-vestibulo Toxicity: An Experimental Study

Objective—Free radicals are involved in gentamicin ototoxicity and vestibular dysfunction and it has been demonstrated that free radical scavengers, such as α-tocopherol, are able to inactive free radicals, attenuating tissue damage. This study was designed to investigate the possible protective effects of α-tocopherol against gentamicin-induced oto-vestibulo toxicity.Material and Methods—Adult albino guinea pigs were divided into four groups and were treated for 2 weeks as follows: Group A, controls; Group B, gentamicin plus corn oil; Group C, gentamicin only; and Group D, gentamicin plus α-tocopherol. To evaluate vestibular function, the animals underwent sinusoidal oscillations in the dark about their vertical and longitudinal axes to evoke horizontal and vertical vestibulo-ocular reflexes (VORs), respectively. Electrocochleographic recordings were performed using an implanted round window electrode. The compound action potentials (CAPs) at 2, 4, 8 and 16 kHz were measured every 5 days. Morphological changes were analysed by means of scanning electron microscopy.Results—Gentamicin induced a consistent reduction in VOR responses and a progressive high-frequency hearing loss of 50–60 dB sound pressure level. α-Tocopherol co-therapy slowed the progression of hearing loss and significantly attenuated the final threshold shifts. The impairment of vestibular function was reduced, as evidenced by an increased VOR gain. The massive loss of outer hair cells in the cochlear basal turn and of cristae ampullaris stereocilia in gentamicin-treated animals was not observed in the cochlea of animals protected with α-tocopherol.Conclusion—This study supports the hypothesis that α-tocopherol interferes with gentamicin-induced free radical formation, and suggests that this drug may be useful in preventing aminoglycoside oto-vestibulo toxicity.

α-Tocopherol protective effects on gentamicin ototoxicity: an experimental study

Gentamicin, acting as an iron chelator, activates membrane lipid peroxidation (MPL) and induces free radical formation, as observed in vitro and in vivo. Antioxidants, such as α-tocopherol, are able to suppress MLP, thus attenuating tissue damage. The present study was designed to investigate the possible protective effects of α-tocopherol on gentamicin ototoxicity. The study was carried out on albino guinea pigs (250–350 g). The animals were divided into four groups: group A (n = 4), injected with corn oil daily at a dose of 100 mg/kg body weight intramuscularly (IM); group B (n = 10), treated with corn oil at a dose of 100 mg/kg body weight and gentamicin base at a dose of 100 mg/kg body weight (IM); group C (n = 10), treated with gentamicin alone at a dose of 100 mg/kg body weight (IM); and group D (n 10), treated with gentamicin at the same dose plus α-tocopherol acetate at dose of 100 mg/kg body weight (IM). Electrocochleographic recordings were made from an implanted round-window electrode. All animals were treated for 14 days. The compound action potentials (CAPs) were measured at 2–16 kHz at days 0, 10, 14 and 18 after treatment. Changes in cochlear function were characterized as CAP threshold shifts. Morphological changes were analysed by scanning electron microscopy. Gentamicin induced progressive high-frequency hearing loss of 50–60 dB SPL. α-tocopherol co-therapy slowed the progression of hearing loss. The significant loss of outer hair cells (OHCs) in the cochlear basal turn in gentamicin-treated animals was not observed in the cochleas of animals protected with α-tocopherol. This study supports the hypothesis that α-tocopherol interferes with gentamicin-induced free radical formation, and suggests that this drug may be useful in protecting OHC function from aminoglycoside ototoxicity, thus reducing hearing loss. Sumario La gentamicina como quelante de hierro, activa la peroxidación de la membrana lipídica (MPL) e induce la formación de los radicales libres, como se ha observado in vitro e in vivo. Los antioxidantes como el α tocoferol son capaces de suprimir la MPL, y por lo tanto atenuar el daño tisular. Este estudio fue diseñado para investigar los posibles efectos protectores del α tocoferol en la ototoxicidad de la gentamicina. El estudio se llevó a cabo en cobayos albinos (250–350 g). Los animales fueron divididos en cuatro grupos: grupo A (n = 4), inyectados intramuscularmente (IM) a diario con aceite de maiz a 100 mg/kg de peso; grupo B (n = 10), tratados con aceite de maiz a 100 mg/kg de peso y gentamicina base a 100 ng/kg (IM); grupo C (n = 10), tratados con gentamicina sola a 100 mg/kg (IM); y grupo D (n = 10), tratados con gentamicina a la misma dosis, más acetato de α-tocoferol a 100 mg/kg (IM). Se tomaron registros electrococleográficos a partir de un electrodo colocado en la ventana redonda. Todos los animales fueron tratados durante 14 días. Se midieron los potenciales de acción compuesta (CAPs) a 2–16 kHz los días 0, 10, 14 y 18 después del tratamiento. Los cambios en la función coclear se describieron como cambios del umbral de los CAP. Se analizaron los cambios morfológicos por medio de un barrido de microscopía electrónica. La gentamicina induce una hipoacusia progresiva para frecuencias agudas de 50–60 dB SPL. La terapia combinada con α-tocoferol disminuyó la progresión de la hipoacusia. La pérdida significativa de células ciliadas externas (OHCs) en la vuelta basal de las cócleas de los animales tratados con gentamicina no se observó en las cócleas de los animales protegidos con α-tocoferol. Este estudio apoya la hipótesis de que el α-tocoferol interfiere en la formación de radicales libres inducida por la gentamicina y sugiere que esta sustancia puede ser útil para la protección de la función de las OHC de la ototoxicidad por aminoglucósidos, con lo que se reduce la hipoacusia.

Auditory and vestibular findings in Fabry disease: a study of hemizygous males and heterozygous females.

Aim: This study aimed to evaluate audiological and vestibular involvement in Fabry disease and the early effects of enzyme replacement therapy with human α‐galactosidase A. Methods: Fourteen patients (10 males, 4 females) aged 14–57 years were studied. Each patient underwent a clinical (history of otological and vestibular aspects, otoscopy) and instrumental (pure tone and speech audiometry, impedance, auditory brainstem response and otoacoustic emission recordings, vestibular caloric tests, electronystagmography during acceleratory stimulation, dynamic posturography) evaluation before starting enzyme replacement therapy. Results: Fifty per cent of patients complained of hearing symptoms (hearing loss, tinnitus, ear fullness). Subjective hearing loss was present in six cases and in three cases it was the first reported symptom of Fabry disease. In six of the seven cases the onset and/or progression of hearing symptoms were sudden. Vertigo or dizziness was reported by four patients and in two cases was associated with hearing symptoms. Audiological evaluation showed sensorineural hearing loss in eight patients (5 males, 3 females). Hearing loss was unilateral in six cases and bilateral in the remaining two cases. The hearing loss (HL) ranged from 30 to 80 dB HL (mean, 43 dB HL) and the lesion was always cochlear. Vestibular examination showed abnormalities in four patients (bilateral weak/abolished response in three cases, side prevalence in one case), which were not related to either the audiological results or the history of vertigo/dizziness.

The role of antioxidants in protection from ototoxic drugs

A number of studies have shown that cisplatin and gentamicin ototoxic effects may result from free radical-mediated damage due to the reduction of antioxidant substances and an increased lipid peroxidation. The authors summarize the results obtained evaluating the auditory and vestibular functions and the inner ear hair cell morphology and survival after administration of antioxidant agents against cisplatin and gentamicin. In the first experiment, albino guinea pigs were treated with gentamicin (100 mg/kg per day, i.m.) alone or gentamicin (100 mg/kg per day, i.m.) plus α-tocopherol (100 mg/kg per day, i.m.) for 2 weeks. In a second experiment, albino guinea pigs were injected with cisplatin (2.5 mg/kg per day) or cisplatin (2.5 mg/kg per day) plus tiopronin (300 mg/kg) for 6 days. Electrocochleographic recordings were made from an implanted round window electrode. In all experiments compound action potentials (CAPs) were measured at 2–16 kHz. Changes in cochlear function were characterized as CAP threshold shifts. To evaluate vestibular function, the animals underwent sinusoidal oscillations in the dark about their vertical and longitudinal axes to evoke horizontal and vertical vestibulo-ocular reflexes (VOR). Frequency stimulation parameters ranged from 0.02 to 0.4 Hz and peak-to-peak amplitude was 20°. Morphological changes were analysed by light microscopy and scanning electron microscopy. Both hearing loss and vestibular dysfunction induced by gentamicin were significantly attenuated by α-tocopherol. However, tiopronin co-therapy slowed the progression of hearing loss in cisplatin-treated animals and significantly attenuated the final threshold shifts. Cisplatin had little effect on the hair cells of cristae ampullares and maculae. Vestibular function was completely preserved in tiopronin co-treated animals. In conclusion, antioxidants such as α-tocopherol or tiopronin interfere with gentamicin and cisplatin damage and this suggests that they may be useful in preventing oto-vestibulotoxicity. Therefore, it is important to develop protective strategies that permit the avoidance of the toxic side effects of these drugs without interfering with their therapeutic effects.

Antioxidant protection against acoustic trauma by coadministration of idebenone and vitamin E.

Idebenone, a synthetic analogue of coenzyme Q, attenuates noise-induced hearing loss by virtue of its antioxidant properties. This study involves a guinea pig model of acoustic trauma where the effectiveness of idebenone is analyzed in comparison with Vitamin E (&agr;-tocopherol) that exhibits a potent antioxidant activity in the inner ear. Idebenone and vitamin E were injected intraperitoneally 1u2009h before noise exposure and once daily for three days; functional and morphological studies were then carried out, respectively, by auditory brainstem responses evaluation, scanning electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay identification of missing and apoptotic cells was also performed. The results showed that the protective effects of idebenone and vitamin E were not additive implying that the two antioxidants may share competitive mechanisms.

Vascular endothelial growth factor (VEGF) expression in noise-induced hearing loss.

Noise-induced hearing loss has been associated with alterations in cochlear blood flow. Our study analyzed the expression of Vascular Endothelial Growth Factor (VEGF) and its functional receptors, Flt-1 and Flk-1, in the cochlear structures of noise-exposed and unexposed guinea pigs. VEGF is a prototypical angiogenic agent, with multiple functions on vascular biology, ranging from vascular permeability to endothelial cell migration, proliferation, differentiation, and survival. Acoustic trauma was induced by a continuous pure tone of 6 kHz, at 120 dB SPL for 30 min. Auditory function was evaluated by electrocochleographic recordings at 2-20 kHz for 7 days. Noise-induced cochlear morphological changes were studied by immunohistochemistry and scanning electron microscopy. The expression of VEGF and its receptors was examined by immunohistochemistry and western blotting analysis. The hearing threshold shift reached a level of 60 dB SPL on day 1 after trauma and underwent a partial recovery over time, reaching a value of about 20 dB SPL on day 7. Outer hair cell loss was more prominent in the area located 14-16 mm from the apex. Increased cochlear VEGF expression was observed in noise-exposed animals, in particular at the level of stria vascularis, spiral ligament, and spiral ganglion cells. No changes were observed in the expression of VEGF-receptors. Our data suggest a role for VEGF in the regulation of the vascular network in the inner ear after acoustic trauma and during auditory recovery, with potentially important clinical and therapeutic implications.

The protective role of tiopronin in cisplatin ototoxicity in Wistar rats

The purpose of this study was to evaluate cisplatininduced ototoxicity and the protective effects of tiopronin. Twenty-four adult Wistar rats served as subjects and were divided into three groups. Eight rats receiving only saline (group A) were used as controls. Eight rats received cisplatin (2 mg/kg) injections (group B) and eight rats received cisplatin and tiopronin (300 mg/kg) (group C) for 8 consecutive days. Both ears of all animals were tested by DPOAE before treatment and on the 4th and 9th days. Seventy-two hours after the final recording session, all animals were killed, and the left cochleas were prepared for electron microscopy and analysed. DPOAE responses were significantly reduced in group B compared to controls ( p_0.05). When tiopronin was added, DPOAE responses were significantly increased compared to those obtained with the administration of cisplatin alone ( p_0.05). The cochleogram showed that tiopronin had a significant protective effect in the basal half and in the lower half of the middle turn. We conclude that tiopronin, a drug effective in protecting against cisplatin nephrotoxicity, is also effective in protecting against cisplatin ototoxicity. Sumario El propósito de este estudio fue evaluar la ototoxicidad inducida por cisplatino y el papel protector de la tiopronina. Se dividieron veinticuatro ratas en tres grupos. Ocho (grupo A), solo recibieron solución salina y se usaron como controles. Ocho (grupo B), recibieron inyecciones de cisplatino (2 mg/kg) y ocho recibieron cisplatino y tiopronina (300 mg/kg) durante ocho días consecutivos. Los dos oídos de todos los animales se examinaron con DPOAE antes del tratamiento y al 4°. y 9°. días. Los animales fueron sacrificados setenta y dos horas después del último registro y las cócleas izquierdas se prepararon y analizaron con microscopio electrónico. Las respuestas con DPOAE fueron significativamente reducidas en el grupo B comparadas con los controles (p_0.05). Cuando se agregó la tiopronina, las respuestas con DPOAE aumentaron significativamente en comparación con las obtenidas con la administración de cisplatino de manera aislada ( p_0.05). El cocleograma mostró que la tiopronina tiene un efecto protector significativo en la mitad del giro basal y en la mitad inferior del giro medio. Concluimos que la tiopronina, droga efectiva en la protección contra la nefrotoxicidad por cisplatino, es también efectiva para proteger en contra de la ototoxicidad por cisplatino.