1,721,034 research outputs found
Cisplatin ototoxicity and role of antioxidant on its prevention
No full textObjective: Highlight the novelties of cisplatin ototoxicity and its prevention, focussing on the role of oxidative stress. Methods: We screened various electronic databases and selected the reports concerning clinical data and animal and in vitro models investigations related to cisplatin-induced ototoxicity and or its prevention by antioxidants. Results: Clinical evidence showed that great advances have been made in the chemotherapy outcomes; nevertheless, the ototoxicity, mainly in paediatric patients, is a crucial issue that must be solved. In vitro and in vivo models were pivotal to deeply describe the toxic effect of the cisplatin and which are the mechanisms of action. These knowledges will help the researcher to improve the chemotherapy protocols in order to avoid the adverse effects without compromise the antitumoral action. Conclusion: Antioxidants seem to be the most promising drugs among the large number of substances tested against cisplatin ototoxicity, however, the inflammatory pathway must be taken into consideration
Giant deep lobe parotid gland pleomorphic adenoma involving the parapharyngeal space. Report of three cases and review of the diagnostic and therapeutic approaches
No full textAim of the present report is to discuss and underline the diagnostic algorithm and the surgical approach to giant parotid pleomorphic adenomas arising in the deep lobe and growing in the parapharyngeal space. Three cases are described and a review is made of the international literature concerning giant deep lobe parotid gland pleomorphic adenoma. Diagnosis was based on imaging, computed tomography scan and magnetic resonance imaging and upon cytology, by means of fine needle aspiration biopsy. The surgical approach varied according to the location of the tumour. All patients were discharged without complications and no cases of permanent facial nerve palsy were observed. An exhaustive pre-operative diagnostic algorithm is required before approaching this lesion. Fine needle aspiration biopsy is, in our opinion, mandatory to avoid histological surprises. The surgical approach should provide excellent visibility with wide surgical exposure to secure local neurovascular structures
Protective effects of alpha-tocopherol and tiopronin against cisplatin-induced ototoxicity
No full textOBJECTIVE:
To investigate the possible protective effects of alpha-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 alpha-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+alpha-tocopherol acetate, (III) cisplatin+tiopronin, (IV) cisplatin+alpha-tocopherol acetate+tiopronin, (V) alpha-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. Alpha-tocopherol and tiopronin co-therapy significantly slowed the progression of hearing loss. Treatment with alpha-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 alpha-tocopherol and tiopronin reduced cochlear outer hair cell loss more than treatment with a single drug. Beneficial effects of alpha-tocopherol and tiopronin on cisplatin-induced nephrotoxicity were observed.
CONCLUSION:
This study supports the hypothesis that alpha-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
Cisplatin ototoxicity in the guinea pig: vestibular and cochlear damage
No full textThe 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
Erbium: yttrium-aluminum-garnet laser stapedotomy--a safe technique
No full textOBJECTIVE:
To standardize the technical parameters of the erbium: yttrium-aluminum-garnet (Er:YAG) laser stapedotomy.
STUDY DESIGN:
Retrospective study of all patients with otosclerosis who underwent stapedotomy from January 2002 to January 2006.
SUBJECTS AND METHODS:
The charts of 152 consecutive patients who underwent stapedotomy were reviewed. The patients were stratified into two groups, according to the instrument used. Stapedotomies were performed in group A, with the OPMI TwinEr:YAG laser; and in group B with manual microperforators.
RESULTS:
No statistically significant differences were found over all measured frequencies, between pre- and postoperative bone conduction thresholds, in each group. At the last postoperative follow-up, vertigo and nystagmus were not detected; two patients in group A and one patient in group B showed persistent tinnitus.
CONCLUSION:
Er:YAG laser stapedotomy is a safe and effective procedure, with no damage of the inner ear when strict adherence to the safety parameters is observed. The Er:YAG laser is definitively suitable for stapes surgery, and represents a useful and safe tool in the armamentarium of otological microsurgery
alpha-Tocopherol protective effects on gentamicin ototoxicity: an experimental study
No full textGentamicin, 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 alpha-tocopherol, are able to suppress MLP, thus attenuating tissue damage. The present study was designed to investigate the possible protective effects of alpha-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 alpha-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. alpha-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 alpha-tocopherol. This study supports the hypothesis that alpha-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
Auditory brainstem and cochlear implants: functional results obtained after one year of rehabilitation
No full textVery little information has been published on the clinical outcome of auditory brainstem implants (ABI). The present paper evaluates results obtained in a patient affected by a bilateral acoustic neuroma in type II neurofibromatosis who received an implant during removal of the residual tumor. One year later surgical revision of the ABI was necessary because no auditory sensation was obtained after ABI activation. Twelve months after the surgical revision, 12 electrodes out of 15 evoked auditory sensation. The results of rehabilitation were compared with those obtained in a group of eight postlingually deaf patients with cochlear implants (CI). Twelve months postoperatively the CI patients identified 97.7 +/- 5.1% of bisyllabic words in a closed set while the ABI patient identified 86%. CI patients recognized 87.1 +/- 11.3% of sentences and 81.3 +/- 14.8% of words with contextual cues while the ABI patient recognized 75% and 65% respectively. Speech recognition improved more slowly in the ABI patient than in the CI patients and his scores for open-set words and sentences without lip reading and contextual cues were poorer. Although the results obtained in the ABI patient were not as good as those obtained in the CI patients, the ABI patient said his quality of life was improved
An unusual complication of cochlear implant: benign paroxysmal positional vertigo
No full textThree days after the initial fitting of the cochlear device a 40-year-old woman complained of severe rotational vertigo following head movements associated with neurovegetative symptoms. Otoneurological evaluation revealed a horizontal paroxysmal positional nystagmus beating towards the lowermost ear, induced by rolling the patient's head from supine both to the right or to the left lateral position suggesting the diagnosis of benign paroxysmal positional vertigo of the left horizontal semicircular canal. The nystagmus characteristics were the same whether the cochlear device was switched on or off. The hypothesis of an otolith dislodging due to the electrical stimulation during the initial fitting is discussed
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