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Biomedical subjects

Patrick J Antonelli

Publications and source records attributed to Patrick J Antonelli.

At least 19 recordsLinked to original sources
PubMed2006

Opening plugged tympanostomy tubes: effect of biofilm formation.

OBJECTIVE: To determine if the presence of a bacterial biofilm impacts the rate of clearing of mucoid plugs from tympanostomy tubes (TTs). STUDY DESIGN AND SETTING: Ex vivo model. Stainless steel Reuter Bobbin TTs (n = 18) were placed in growth medium with Pseudomonas aeruginosa and Streptococcus pneumoniae for 12 days to promote biofilm formation. Tympanostomy tubes (n = 18) placed in growth medium, without bacteria, for 12 days served as controls. Biofilm formation was assessed by scanning electron microscopy. All TTs were filled with middle ear mucus and allowed to dry, thereby forming a plug. TTs were placed in a model ear chamber, covered with ofloxacin otic solution, and the time to clear each plug was recorded. RESULTS: Biofilm formation was consistently encountered on TTs exposed to bacteria but in no TTs in the control group. There was a significant effect of the biofilm on plug clearance, favoring TTs without a biofilm (P = 0.0333). Although there was no significant difference in the proportion of unplugged TTs (P = 0.264), TTs with a biofilm did not clear plugs as rapidly as TTs without a biofilm (P = 0.0416). CONCLUSIONS: The presence of a biofilm may slow the time to clear mucoid TT plugs, but it does not seem to affect the overall proportion of TTs that are unplugged.

Anti-Bacterial Agents↗
PubMed2006

Hearing loss with stapedotomy and treated otitis media.

OBJECTIVE: To determine if treated Pseudomonas aeruginosa otitis media (PA OM) increases the risk of sensorineural hearing loss (SNHL) with stapedotomy. STUDY DESIGN AND SETTING: PA OM was induced in 28 guinea pigs. Half of the animals underwent unilateral stapedotomy before antibiotic therapy (untreated), and half underwent stapedotomy after treatment (treated). Control animals underwent saline injections followed by stapedotomy. Electrocochleographic thresholds were measured before and after stapedotomy. Temporal bones were analyzed histomorphologically. RESULTS: Less SNHL was seen after stapedotomy in treated ears than in untreated ears (P = 0.0268). SNHL after stapedotomy in treated ears was similar to controls (P = 0.9370). Severe damage to cochlear outer hair cells was found in untreated ears. CONCLUSIONS: Ears with PA OM treated previously are not at increased risk of SNHL with stapedotomy. SIGNIFICANCE: Stapedotomy may be carried out with caution in the setting of inactive, chronic OM.

Animals↗
PubMed2006

Alpha1-antitrypsin single dose adjuvant therapy for acute otitis media.

OBJECTIVES: Proteases have been shown to play a role in the pathogenesis of otitis media. Inhibition of these proteases can improve treatment outcomes in certain conditions. The goal of this study was to determine if intratympanic administration of a single dose of the protease inhibitor, recombinant alpha 1-antitrypsin (rAAT), can facilitate resolution of acute otitis media (AOM) in the chinchilla. METHODS AND MEASURES: Pneumococcus was injected into both middle ears of 12 chinchillas. After 3 to 4 days, middle ears were cultured, systemic antibiotics were initiated, and rAAT or its vehicle was administered into the middle ears of all animals. Serial tympanic membrane (TM) scoring, tympanometry, and auditory-evoked brain stem response testing were performed. Animals were sacrificed at varying timepoints and temporal bones studied for objective measures of OM. RESULTS: Although not reaching statistical significance, there was a trend to more rapid resolution of AOM in rAAT-treated ears. Tympanometry, auditory thresholds, and quantitative histologic parameters did not differ between rAAT and vehicle treated ears. CONCLUSIONS: A single dose of intratympanic rAAT likely does not facilitate the resolution of antibiotic-treated pneumococcal AOM in the chinchilla model. Serial administration of this protease inhibitor may be necessary to see a significant treatment effect.

Acute Disease↗
PubMed2006

Mitigation of hearing loss from semi-circular canal transection in pseudomonas otitis media with ciprofloxacin-dexamethasone irrigation.

HYPOTHESIS: Irrigation of the mastoid with a quinolone antibiotic-steroid solution may mitigate hearing loss caused by iatrogenic semicircular canal injury in the presence of Pseudomonas aeruginosa (PA) otitis media (OM). BACKGROUND: Studies have shown the cochlea to be more vulnerable to semicircular canal transection (SCT)-related hearing loss in the presence of PA OM. Prophylactic systemic antibiotics and steroids may decrease this hearing loss, but SCT is usually not planned. The aim of this study was to determine if irrigation with ciprofloxacin-dexamethasone (cipro-dex) could improve hearing outcomes following SCT in PA OM. METHODS: PA OM was induced in 28 animals. After three to five days, unilateral SCT was performed in each animal, with sham SCT on the contralateral ear. At surgery, half of the animals (n = 14) underwent irrigation of the both mastoid bullae with cipro-dex; the second group of animals (n = 14) underwent irrigation of the bullae with sterile saline. Auditory thresholds were obtained immediately prior to SCT and 7-10 days after SCT. RESULTS: SCT ears treated with cipro-dex showed a mean click threshold improvement of 4.6 dB from pre-transection to 7-10 days post-transection, whereas thresholds in the SCT ears treated with saline worsened by 7.5 dB (p = 0.15). CONCLUSION: Irrigation of the guinea pig bulla with cipro-dex following SCT in the setting of PA OM appears safe and may yield beneficial effects on hearing.

Animals↗
PubMed2005

Opening plugged tympanostomy tubes: effect of inner diameter and shaft length.

OBJECTIVE: To determine whether tympanostomy tube (TT) inner diameter or shaft length impacts the rate of mucoid plug clearance. STUDY DESIGN AND SETTING: Ex vivo model. Silicone TTs with different inner-diameters (ID) and shaft-length (SL) pairings (1.14 mm ID x 12 mm SL versus 1.14 mm ID x 1 mm SL; 1.14 mm ID x 4.8 mm SL versus 1.32 mm ID x 4.8 mm SL) were plugged with middle-ear mucus (n = 15 per group) and placed in a model ear chamber. Ofloxacin otic solution was instilled into the chamber to cover the plugged TT, and the time to clearance of each plug was recorded. RESULTS: TTs with larger IDs ( P = 0.019) and greater SLs ( P = 0.033) cleared plugs more rapidly. However, the difference in the percentage of tubes that unplugged was not significant ( P = 0.151). CONCLUSIONS: Rate of ex vivo TT plug clearance may be altered by changing TT ID and SL.

Anti-Bacterial Agents↗
PubMed2005

Gastric reflux is uncommon in acute post-tympanostomy otorrhea.

OBJECTIVE: Acute post-tympanostomy otorrhea (APTO) is a common complication of tympanostomy tube placement. APTO has been related primarily to viral upper respiratory infections and external ear contamination. Elevated levels of gastric enzymes have been found in a large proportion of chronic middle ear effusions, implicating gastric reflux (GR) in its pathogenesis. Thus, our objective was to determine whether GR may be a contributing factor in the development of APTO. STUDY DESIGN AND SETTING: Prospective, nonrandomized design. Otorrhea samples were collected from children with APTO. Total pepsinogen concentrations were measured with a commercial ELISA, using a pepsinogen I-specific capture antibody and horseradish peroxidase detection antibody. RESULTS: Twenty-six samples from 24 patients were collected and analyzed. Eight samples demonstrated measurable pepsinogen I, but the measured concentrations, 2-17 mg/L, were below the normal serum reference ranges. CONCLUSIONS: GR does not play a major role in the development of APTO in children.

Adolescent↗
PubMed2005

Cochlear implant magnet displacement with minor head trauma.

OBJECTIVES: Manufacturers have introduced cochlear implants (CIs) with removable magnets to allow for magnetic resonance imaging after placement. The purpose of this study was to describe magnet displacement as a new CI complication and to suggest a possible treatment option to prevent its recurrence. STUDY DESIGN: Retrospective case series. METHODS: The records of 3 young males who experienced CI magnet dislodgement were reviewed and compared against records from the institutional implant database. RESULTS: Magnet displacement was observed only in young males (14% of male children) who received CI with removable magnets. This occurred 13-14 months after CI placement. Magnets were replaced under general anesthesia, and the scalp was bolstered with a dermal allograft. Recurrent magnet dislodgement was encountered in 1 patient, 6 months later. CONCLUSIONS: Magnet displacement may be a relatively common complication after minor head trauma in pediatric patients with certain CIs that have removable magnets.

Child, Preschool↗
PubMed2005

Preoperative antibiotic and steroid therapy and hearing loss caused by semicircular canal transection in pseudomonas otitis media.

OBJECTIVE: The purpose of this experiment was to determine whether preoperative administration of antibiotics and corticosteroids can attenuate the severity of hearing loss (HL) with semicircular canal (SC) transection in a guinea pig model of Pseudomonas aeruginosa (PA) otitis media (OM). Study design and setting Prospective and controlled. METHODS: OM was induced in 64 pigmented guinea pigs by bilateral, transtympanic injection of PA. Two to 4 days later, 1 horizontal SC was randomly transected. In the 1st series, antibiotic therapy was initiated either immediately before or after surgery. In the 2nd series, all animals received preoperative antibiotics, and half received dexamethasone before surgery. Hearing was tested before and after surgery. RESULTS: PA was recovered in all ears. SC transection was associated with significant HL. HL was better in animals given antibiotics preoperatively (clicks, 16 versus 32 dB, P = 0.0220). Addition of preoperative steroids did not significantly further reduce HL (7 versus 14 dB for clicks, P = 0.6919). CONCLUSIONS: HL caused by SC transection in PA OM may be attenuated with preoperative antibiotic therapy in the guinea pig.

Animals↗
PubMed2005

Hearing loss and extent of labyrinthine injury in Pseudomonas otitis media.

OBJECTIVES: To determine if the severity of hearing loss due to semicircular canal transection (SCT) in Pseudomonas otitis media (POM) is a function of the extent of the labyrinthine injury. METHODS: POM was induced bilaterally in 45 guinea pigs. After 2 to 4 days, SCT was performed in one 1 on the horizontal canal, the superior canal, or both the horizontal and the superior canals. Auditory-evoked brainstem responses were measured before and after SCT. RESULTS: POM was induced bilaterally in all animals. Elevation of click thresholds was found in almost all SCT ears of all 3 groups; however, there were no significant differences between groups. Comparing the SCT ear to the contralateral, control ear, mean hearing losses in the horizontal, superior, and horizontal + superior SCT groups were 23 dB, 27 dB, and 24 dB, respectively. CONCLUSIONS: Hearing loss does not correlate with extent of labyrinthine injury in POM in the guinea pig. EBM RATING: B-2.

Animals↗
PubMed2005

Inflammatory proteases in chronic otitis externa.

OBJECTIVES: Proteases are known to contribute to the pathogenesis of chronic inflammatory skin conditions such as atopic dermatitis and psoriasis. Inhibition of these proteases has shown promise in the treatment of these skin conditions. The purpose of this study was to measure the matrix metalloproteinases (MMP) and human neutrophil elastase (HNE) activities in chronic otitis externa (COE) and to determine whether administration of protease inhibitors recombinant alpha 1-antitrypsin (rAAT) and ilomastat might reduce these protease activities. STUDY DESIGN: Prospective and ex vivo. METHODS: Twenty-five ear canals with COE and 34 with no pathology (i.e., controls) were debrided and filled with saline. After a tragal pump and 1 to 2 minutes, the washes were collected and analyzed for MMP and HNE activities and the inhibitory activity of rAAT and ilomastat on these proteases, respectively. RESULTS: MMP and HNE levels were significantly higher (P = .0057 and .0112) in ears with COE than normal ears. MMP activity greater than 3 mAU/minute was observed in 30% of COE and 0% of controls (P = .0270). HNE activity greater than 3 mAU/minute was found in 77% of COE versus 7% of controls (P < .0001). Ilomastat and rAAT inhibited 60% of MMP and 98% of HNE activity, respectively, in COE ears. CONCLUSIONS: Elevated levels of proteases found in COE, MMP, and HNE may be inhibited with ilomastat and rAAT. The therapeutic potential of these protease inhibitors warrants investigation.

Chronic Disease↗
PubMed2005

Preoperative computed tomography may fail to detect patients at risk for perilymph gusher.

Perilymph gusher (PG) is a very rare occurrence that can lead to an adverse outcome during inner ear surgery. In the absence of a family history of X-linked mixed deafness syndrome, surgeons may have difficulty determining if a patient is at risk preoperatively. Radiographic imaging is often performed in an attempt to identify such a possibility, but there are few data to support the value of negative studies. We conducted a retrospective study of 3 cases of PG in which findings on preoperative high-resolution computed tomography (CT) of the temporal bone had been interpreted as normal. We reviewed these CTs to discern if they did in fact demonstrate any abnormalities that might have indicated a risk of PG, and we found that the original radiologist had missed a dilated internal auditory canal and a deformity of the cochlear modiolus in the affected ear of 1 of these patients. No abnormality was detected on review of the CTs of the other 2 patients. Therefore, we conclude that negative CT findings do not necessarily rule out a risk of PG.

Adult↗
PubMed2004

A log-normal distribution model of the effect of bacteria and ear fenestration on hearing loss: a Bayesian approach.

Chronic ear infection is a potentially life-threatening illness that medical doctors typically treat with ear surgery. Despite the success of this treatment, complications can occur due to bacteria infection. Surgeons believe that this infection causes the patient to have clinically significant hearing damage. In order to understand such complications, surgeons must quantify the effect of bacteria, their toxins and ear surgery on hearing loss. To this end, the other two authors of this paper performed two experiments on guinea pigs to measure hearing thresholds following a bacterial infection and surgery of the inner ear. The response variable in these experiments is hearing thresholds measured in decibels (dB). The problem in analysing such experiments is that the hearing threshold observations often suffer from missing data and censoring mechanisms of various types. Additionally, the distribution of hearing thresholds has heavy tails and is peaked. In order to account for the above statistical issues, we present a Bayesian method with a location-shifted log-normal distribution. The method accounts for the uncertainty in the data collection mechanism and the parameters associated with a location-shifted log-normal distribution. We refer to one of the parameters as the "location-shift" parameter. The Bayesian approach provides a posterior distribution of the location-shift parameter that we compare with values estimated in previously published studies. The immediate goal of our proposed method was to quantify the effects of ear surgery and bacteria infection on hearing loss. Thus, we present the merits of the method in the form of a case study, and report posterior distributions of mean hearing loss, probability of clinically significant hearing loss and relative risk. The results show that surgeon 2, using the surgical procedure "oval window", poses a greater than 40 per cent chance of a 15dB hearing loss regardless of injection of bacteria or not. However, surgeon 1, using the surgical procedure "semicircular canal", does not pose a significantly greater than 40 per cent chance of a 15dB hearing loss unless there is a Pseudomonas aeruginosa-induced infection.

Aged↗
PubMed2004

Hearing loss with semicircular canal fistula in exotoxin A-deficient Pseudomonas otitis media.

OBJECTIVE: The study goal was to compare the severity of hearing loss with semicircular canal injury in the presence of otitis media (OM) due to an exotoxin A-producing strain of Pseudomonas aeruginosa (PA+) and an exotoxin A-deficient daughter strain (PA-). METHODS: PA+ or PA- was injected bilaterally into guinea pig ears. Three days later, unilateral lateral semicircular canal transection was performed. Hearing was tested before and after transection. RESULTS: PA OM was induced in all injected ears. Significant elevation of click and 12-kHz thresholds (P < 0.0001) were encountered in PA+-infected ears. No significant threshold elevations were encountered in PA--infected ears. CONCLUSION: Hearing loss resulting from canal injury in the presence of Pseudomonas OM may be mediated by exotoxin A. SIGNIFICANCE: Treatment to neutralize the effects of exotoxin A may minimize the risk of hearing loss with canal fistula in chronic OM.

ADP Ribose Transferases↗
PubMed2004

Hearing loss with semicircular canal transection and Pseudomonas aeruginosa otitis media.

OBJECTIVE: To determine if Pseudomonas aeruginosa (PA) otitis media (OM) increases the risk of sensorineural hearing loss (SNHL) with semicircular canal transection in the guinea pig model. METHODS: PA was injected transtympanically into both middle ears of pigmented guinea pigs. Saline-injected animals served as controls. Two to 4 days after injection, one horizontal semicircular canal was transected and sealed. Hearing was tested using electrocochleography before and after transection. RESULTS: PA-OM was induced in all PA-injected ears. Five days after semicircular canal transection, click-evoked thresholds were significantly elevated in ears with PA-OM (P = 0.00009) but not in saline-injected ears (P = 0.398). CONCLUSION: Violation of the inner ear in the presence of PA-OM is associated with increased risk of SNHL in the guinea pig. SIGNIFICANCE: Factors unique to PA infection may be responsible for SNHL with labyrinthine injury in humans with chronic otitis media.

Animals↗
PubMed2004

Bacterial biofilms may contribute to persistent cochlear implant infection.

OBJECTIVES: To determine if bacterial biofilms are present on the surface of extruding or persistently infected cochlear implants. METHODS: Scanning electron microscopy was performed on cochlear implants removed from two patients because of recalcitrant infection, two implants removed secondary to device failure, and two devices that had never been implanted. Preparations were examined by experienced microbiologists for the presence of bacterial biofilms. RESULTS: Microorganisms and amorphous extracellular debris were found on the surface of the infected cochlear implants and the implants removed because of device failure. Biofilm formation was deemed definite in one infected device and possible in the other explanted devices. The never-implanted controls demonstrated microbial contamination without exopolymeric matrix, inconsistent with biofilms. CONCLUSION: Bacterial biofilm formation may play a role in recalcitrant cochlear implant infections. This may have profound implications for the treatment of cochlear implant infections.

Adolescent↗