[Show abstract][Hide abstract] ABSTRACT: The protective effect of dexamethasone (DEX) against noise-induced trauma, as reflected in hair cell destruction and elevation in auditory brainstem response (ABR) sensitivity, was assessed in guinea pigs. The animals were administered DEX (1, 10, 100, and 1000 ng/ml) or artificial perilymph (AP) via a mini-osmotic pump directly into scala tympani and, on the fourth day after pump implantation, exposed to 120 dB SPL octave band noise, centered at 4 kHz, for 24 h. Animals receiving DEX demonstrated a dose-dependent reduction in noise-induced outer hair cell loss (significant at 1, 10 and 100 ng/ml DEX animals compared to AP control animals) and a similar attenuation of the noise-induced ABR threshold shifts, observed 7 days following exposure (significant at 100 ng/ml DEX animals compared to AP control animals). These physiological and morphological results indicate that direct infusion of DEX into the perilymphatic space has protective effects against noise-induced trauma in the guinea pig cochlea.
No preview · Article · Nov 2004 · Hearing Research
[Show abstract][Hide abstract] ABSTRACT: This study demonstrates the attenuation of aminoglycoside ototoxicity by cochlear infusion of dexamethasone (Dex) using a microcannulation-osmotic pump delivery system. The results indicate that treating the cochlea with Dex both before and after kanamycin administration was more effective in preventing ototoxicity than Dex treatment only after kanamycin administration. A concentration of 1 ng/ml Dex showed the greatest protective effect on both kanamycin-induced threshold shift of the auditory brainstem response and outer hair cell survival. These results show that the Dex treatment attenuates both functional and structural damage of the inner ear from aminoglycoside toxicity.
No preview · Article · Jun 2002 · Hearing Research
[Show abstract][Hide abstract] ABSTRACT: We describe twenty patients with secondary hyperparathyroidism (SHP) treated with surgery. The causes of SHP were chronic renal failure with hemodialysis in all the patients. Twelve patients were male and eight were female, ranging in age from 35 to 63 years. The most frequent complaint before surgery was severe joint pain in the knees, feet, shoulders, back and ankles. Of these complaints, bone pain and pruritus such as irritability, diminished rapidly after surgery. Preoperative examinations with an echogram and scintigram were useful for indicating the number and location of parathyroid glands. Patients were treated with a combination of total parathyroidectomy and autotransplantation of autologous parathyroid tissue to the forearm. There were no complications, such as recurrent nerve palsy and bleeding. We conclude that the combination of total parathyroidectomy and retransplantation of parathyroid tissue is one of the best surgical approaches.