title: Persistence of the otoprotective effect: how long does otoprotection against amikacin lasts?
abstract: There is evidence that a "resistance phenomenon" occurs when a none-damaging dose of amikacin protects the hair cells from ototoxicity. Our goal is to prove that this resistance is persistent.
  
  
  METHODS
  Experimental study - 14 albino guinea pigs (Cavia porcellus) divided into three groups. The auditory function was assessed by distortion product otoacoustic emissions (DPOAE): before exposure to amikacin, on the 15th day after the non-damaging dose was injected, at the end of the damage dose injection and prior to decapitation.
  
  
  RESULTS
  Group A (control) presented normal hearing and histological pattern. Group B (amikacin 20mg/kg/day (IM) for 30 days and affecting dose (400 mg / kg / day) for 12 days and Group C (same protocol of Group B, but kept for 60 days and slaughtered), the DPOAE confirmed normal auditory function in the pre-exposure and maintenance of the standard-dose; however, significant loss of auditory function after the end of the damaging dose injection.
  
  
  CONCLUSIONS
  The protection phenomenon did not extended for a period of 30 to 60 days after the application of damaging doses of amykacin.
authors.affiliation: Departamento de Oftalmologia, Otorrinolaringologia e CIrurgia de Cabeça e Pescoço Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes no. 3900, Ribeirão Preto - SP, Brazil. andreiaoliveira@hcrp.fmrp.usp.br
authors.forename: Andreia Ardevino de
authors.initials: AA
authors.lastname: Oliveira
authors.forename: Matheus de Souza
authors.initials: Mde S
authors.lastname: Campos
authors.forename: Adriana de Andrade Batista
authors.initials: Ade A
authors.lastname: Murashima
authors.forename: Maria
authors.initials: M
authors.lastname: Rossato
authors.forename: Miguel Angelo
authors.initials: MA
authors.lastname: Hyppolito
authors.forename: José Antônio Apparecido de
authors.initials: JA
authors.lastname: Oliveira
mesh_terms: D000583:Amikacin / Q000008:administration & dosage / Q000633:toxicity*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects* / Q000648:ultrastructure; D034381:Hearing Loss / Q000139:chemically induced*; D008855:Microscopy, Electron, Scanning; D017084:Otoacoustic Emissions, Spontaneous / Q000187:drug effects*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D000583:Amikacin