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.     

Incidence of acute otitis media and mastoiditis in cochlear implanted children

Objectives: To examine the incidence of acute otitis media (AOM)and mastoiditis in children after cochlear implantation (CI) and to evaluate the role of mastoidectomy on the natural history of AOM in implanted children by comparing surgical approaches.Methods: Retrospective case review. The study cohort included children up to age 8 years at the time of CI between 1993–2001 and followed-up at least 28 months. One hundred forty-five children were divided into 2 groups. One group (97 children) underwent the classic mastoidectomy posterior tympanotomy approach (MPTA) and the other group (48 children) underwent cochlear implantation using the suprameatal approach (SMA) without mastoidectomy. The incidence of AOM and mastoiditis before and after the implantation was compared between the 2 groups.Results: Fifty-five of the 145 children had a history of one or more episodes of AOM prior to implantation. The incidence of pre- and postimplantation AOM was similar for the 2 groups (P = 0.6607 and P = 0.5104, respectively). Mastoiditis developed in 8 children, all but 1 older than 2 years of age and all in the MPTA group.Conclusions: AOM and mastoiditis represents common complications of CI surgery and are successfully treated by antibiotics. The incidence of post-CI AOM was lower than that of pre-CI AOM, a finding unrelated to the surgical approach. Mastoiditis occurred only in the MPTA group.     

Effect of vitamin E on adriamycin- induced nephrotoxicity at the ultrastructural level in guinea pigs.

It is known that Adriamycin, which is widely used in the treatment of various neoplastic conditions, exerts toxic effects in several organs. In this study, we have established that vitamin E has some beneficial effects on the kidney by protecting it from some of the toxicity induced by Adriamycin. A study was carried out which comprised one control group and two experimental groups of guinea pigs. In the experiment Adriamycin was administered either alone (group II) or together with vitamin E (group III). The results of groups II and III were compared with controls (group I). The kidneys were subsequently removed and examined by routine electron microscopic techniques. We found that vitamin E administered together with Adriamycin could reverse some of the degenerative changes caused by Adriamycin.     

Wound healing in vitamin C-deficient and nondeficient guinea pigs: a pilot study

Wound contraction and scar contracture were studied in guinea pigs deficient (stage I) and nondeficient in vitamin C (stage II). Some vitamin C-deficient and some nondeficient animals were subjected to excision of an ellipse of skin measuring 40 X 20 mm in an area not containing panniculus carnosus. The wounds were approximated without undermining. In other animals, the same type of excision was carried out; however, the wounds were left unapproximated. Wound contraction was studied in the unapproximated group and scar contracture was studied in both groups for six months postoperatively. Scar contracture was found to be more significant in animals with unapproximated wounds who were on regular diets, implying a role for vitamin C in this process. Wound contraction was noted to take place in scorbutic and non-scorbutic groups at the same rate. These findings are in line with previous studies done in areas containing panniculus carnosus, implying that the role of this cutaneous muscle in contraction and contracture is not essential in either deficient or nondeficient states. Two animals also developed a remarkably thicker scar than their counterparts while in a deficient state. The relationship between vitamin C deficiency and the formation of hypertrophic scar in guinea pigs is postulated.     

Reading performance in children with otitis media.

OBJECTIVE: To examine whether middle ear diseases and the associated hearing loss in early childhood affect reading performance later at school. STUDY DESIGN AND SETTING: One hundred and sixty children, 6.5 to 8 years of age, were enrolled in this study: 80 children with a history of recurrent infections and/or prolonged periods of effusions of the middle ear before the age of 5 years, and 80 healthy children without any history of middle ear disease. Data were collected from the medical records of the children. Every child underwent a complete otological and audiological evaluation, followed by special reading tests. RESULTS: The study group performed more poorly, in all reading tests, as compared to the controls ( P < 0.001). CONCLUSION: Children with recurrent or prolonged middle ear diseases during the first five years of life tend to be at greater risk for delayed reading than aged-matched controls with no previous middle ear diseases.     

Blood vessels in the epiphyseal cartilage of vitamin A-deficient rats

A deficiency of vitamin A in the diet of weanling rats resulted in a vascular penetration of the proximal tibial epiphyseal cartilage. This response might be due to either impaired diffusion in an altered cartilage matrix or as a result of microfractures in the growth disc.

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Zusammenfassung Ein Vitamin A-Mangel in der Nahrung von entwöhnten Ratten erzeught ein Eindringen von Gefäßen in den Epiphysenknorpel des proximalen Tibiaendes. Diese Wirkung könnte entweder durch eine gestörte Diffusion in der veränderten Knorpelmatrix oder infolge von Mikrofrakturen in der Wachstumsfuge entstehen.

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Résumé Une deficience alimentaire en vitamine A provoque chez le rat sevré une pénétration vasculaire dans le cartilage épiphysaire proximal du tibia. Ce fait peut être lié soit à un trouble de diffusion dans la matrice cartilagineuse altérée soit à des microfractures dans la métaphyse.

     

The role of rhinitis in chronic otitis media.

OBJECTIVE: We investigated the role of allergic rhinitis in chronic otitis media (otitis media with effusion [OME] and chronic perforation of the tympanic membrane) in S?o Paulo, Brazil and whether there is any association between these diseases. STUDY DESIGN AND SETTING: We studied 51 patients followed in the otologic group of the Otorhinolaryngology Division of the University of S?o Paulo Hospital. The patients were divided into 3 groups: allergic rhinitis, nonallergic rhinitis with eosinophils syndrome (NARES), and patients with types of rhinitis or without rhinitis. We analyzed the age, gender, intensity of the nasal disease, surgical procedure, and surgical results in each group. RESULTS: We found about 50% of patients presenting with nasal disease and nasal eosinophilia (33.33% of allergic and 15.69% of NARES). CONCLUSION: Nasal disease has an impact on otologic middle ear disease, considering that the normal nasal mucosa do not have eosinophils.     

Association of reflux with otitis media in children.

OBJECTIVES: To confirm the finding of pepsin/pepsinogen in middle ear fluid of children with chronic or recurrent otitis media (OME or ROM), and to ask parents about symptoms associated with gastroesophageal reflux (GER). METHODS: Middle ear fluid was collected from children undergoing tympanostomy tube placement. We tested this fluid for pepsin/pepsinogen using a proteolytic enzyme assay and an ELISA. Parents completed questionnaires about symptoms of GER in their children. RESULTS: We collected 36 samples from 22 children; 16 of 22 children (73%) were positive with the proteolytic assay; 17 (77%) were positive with ELISA. Questionnaires did not show increased GER symptoms. CONCLUSIONS: We replicated the finding of pepsin/pepsinogen in middle ear fluid of children with OME or ROM, but did not find any increase in GER symptoms. Further research is needed to establish a causative link between GER and OM.     

Self-protection against aminoglycoside ototoxicity in guinea pigs.

BACKGROUND: Amikacin is a semisynthetic aminoglycoside. It acts against most of the microbial species. Amikacin limitation of the therapeutic application is the ototoxicity which promotes permanent lesions in the cochlear system. Aminoglycoside antibiotics have ototoxic potential. The target cells are preferentially the outer hair cells in the cochlear basal turns. Amynoglicoside antibiotics can quelate iron forming a complex with oxidate properties and promotes the formation of free radicals. Responsible for production of lesions in the hair cells. OBJECTIVE: The objective of the present investigation was to determine whether the use of the aminoglycoside amikacin at small doses may lead to the occurrence of some types of resistance to or protection against ototoxicity of the drug by analyzing lesions to the organ of Corti by scanning electron microscopy. METHODS: The study was conducted on 31 guinea pigs that were divided into 4 groups, amikacin was administered intramuscularly. The groups consisted of: group A = control group: 5 animals (10 cochleae); group B = 5 animals (10 cochleae), amikacin 20 mg/kg/day for 30 days; group C = 7 animals (13 cochleae), amikacin 400 mg/kg/day for 12 days; group d = 14 animals (26 cochleae) amikacin 20 mg/kg/day for 30 days, followed by 400 mg/kg/day for 12 days. Histological studies were performed by scanning electron microscopy. Three cochleae were excluded. RESULTS: In groups A and B, the cells were normal in all cochleae, in group C there were extensive lesions of the 2 more basal turns, and in group D there was a significant reduction of lesions in the 2 more basal turns compared with group C, which had received the ototoxic dose of amikacin alone. CONCLUSION: We conclude that the non-ototoxic dose of amikacin administered before the ototoxic dose of the same antibiotic had a statistically significant protective effect on the 2 more basal turns of the guinea pig cochlea.     

Medical treatment of chronic otitis media with effusion (secretory otitis media)

To determine whether antimicrobial therapy is of value in the treatment of chronic otitis media with effusion (secretory otitis media), we treated 1,429 4- to 8-year-old children--2224 affected ears--with a fixed regimen of an antibiotic mixture (Pediazole) for 10 days and a decongestant (Novafed) for 30 days. We observed the children monthly to determine the rate of clearance. Validity of diagnosis was greater than 90% with an algorithm of pneumatic otoscopy and tympanometry. Medication compliance was not measured. At 1 month, 45% of the children (48% of the ears) had cleared and at 2 months, 60% of the children (63% of the ears) had cleared. Factors such as sex and prior treatment in the preceding 3 months were no different in the cured vs. the uncured groups. Age significantly influenced the cure rate (P less than 0.0001); the older the child, the higher the clearance rate. Tympanograms type 5, 8, and 12-14 were significantly more prevalent in the uncleared group (P = 0.0001). The clear rate for unilateral cases was 76% and for bilateral cases, 47% (P less than 0.0001). Children with chronic otitis media with effusion are most likely to be cured by medical therapy/time if they are older, have unilateral disease, or a peaked tympanogram. Surgery should be withheld in these children for 2 or more months to permit the highest rate of spontaneous resolution.     

Hydroxocobalamin therapy of cyanide intoxication in guinea pigs.

The efficacy of hydroxocobalamin (vitamin B12a) as a specific, nontoxic antidote in acute cyanide poisoning was tested. Guinea pigs receiving lethal intravenous NaCN injections were treated with either vitamin B12a or saline solution. There was a statistically significant antidotal effect of the vitamin. No toxic effect was observed with large doses of the vitamin.     

Pseudomonas otitis media after eustachian tube obstruction.

Previous experiments have shown that Pseudomonas aeruginosa may infect the middle ears of chinchillas by way of the eustachian tube and that chinchillas with acute otitis media (AOM) are more susceptible to pseudomonas infection than animals without AOM. The purpose of this experiment was to examine the effects of otitis media with effusion (OME), induced by means of eustachian tube obstruction, on middle ear susceptibility to nasal inoculation of P. aeruginosa. Chinchilla eustachian tubes were obstructed with silicone rubber sponge bilaterally; OME developed in eight animals (11 ears)--three bilaterally and five unilaterally--and persisted for 6 months. Ten chinchillas with normal eustachian tube function served as controls. All animals were nasally inoculated with 5 x 10(6) colony-forming units of P. aeruginosa. Pseudomonas otitis media developed in eight of 11 OME ears with effusion, none of five ears without OME, and four of 20 control ears (chi 2 = 11.782, p = 0.003). Therefore, P. aeruginosa can infect the middle ear by way of the eustachian tube. Tubal dysfunction may lead to the development of chronic suppurative otitis media by increasing tubotympanic susceptibility to opportunistic pathogens.     

Facial palsy associated with acute otitis media.

OBJECTIVE: Facial palsy secondary to acute otitis media is rarely encountered today. The aim of the present study was to review the characteristics of the disease and propose the proper management. STUDY DESIGN: File review. Setting University-affiliated tertiary referral center. MAIN OUTCOME MEASURES: Disease course, management and outcome were recorded. RESULTS: Sixty-five children with facial palsy were identified, of whom 13 (20%) had acute otitis media. The otitis media preceded the facial palsy in all cases by 1 to 21 days (average 5 days). House-Brackmann grade ranged from 2 to 5 (average 3.5). The recovery period was varied and unpredictable, ranging in duration from 1 to 180 days (average 68 days). Treatment was conservative, except for insertion of a ventilation tube in 2 cases. CONCLUSIONS: Considering that all the patients recovered, conservative treatment, including myringotomy and intravenous antibiotics, may be the correct approach to facial palsy associated with acute otitis media.     

Tympanomastoidectomy for chronic otitis media without cholesteatoma.

A series of 221 ears with chronic suppurative otitis media without cholesteatoma is presented--84% of the cases were treated using one-stage tympanomastoidectomy and 15% underwent cortical mastoidectomy with planned second-stage tympanoplasty. Mean follow-up period was 6.3 years. Control of infection succeeded in 92% after the primary operation. Failures were most common in ears infected with Pseudomonas aeruginosa. Postoperative cholesteatoma developed in 5 ears (2.2%). Hearing results were unsatisfactory; a postoperative air-bone gap within 20 dB was achieved in only 62%. In revision operations, retained mastoid air cells were found in 64% of ears with recurrent or persistent discharge. Thirty-seven percent of patients with unsuccessful outcome were observed to have a possible underlying or concomitant disease. The importance of intensive preoperative conservative treatment and careful surgical technique is stressed.     

Efficacy of surgical treatment of chronic otitis media.

This article presents our results of surgical treatment of chronic otitis media (COM) and discusses its efficacy regarding the control of disease and hearing results. A retrospective chart review of 84 ears was performed. Forty-one ears with noncholesteatomatous COM underwent tympanomastoidectomy, 43 ears with cholesteatoma were managed according to the extension of the disease, closed mastoidectomy was indicated in 19 cases, and open mastoidectomy was performed in 24 ears. In the group without cholesteatoma, a stable ear with closed tympanic membrane was obtained in 85% of cases after the first procedure. The speech response threshold before and after surgery was 38 and 26 dB. In patients with cholesteatoma, a dry ear was achieved in 79% of cases on both techniques after the first intervention. The recurrence rate of cholesteatoma was 10% for the closed technique and 4% for the open technique. The mean preoperative and postoperative SRTs for the closed technique were 30 and 29 dB and for the open technique were 50 and 54 dB. The surgical treatment for COM can be a rewarding procedure if a correct technique is indicated. The surgery should be tailored regarding the clinical stage and intraoperative findings in each case.     

Halothane hepatotoxicity in guinea pigs

A recently reported animal model of halothane-associated hepatotoxicity in males of a colored strain of guinea pig was further characterized as to possible sex and strain specificity in outbred albino Amana, inbred albino Hartley, inbred colored strain 2, and inbred colored strain 13 guinea pigs. Exposure to 1% halothane for 4 hr in 21% O2 proved to be hepatotoxic in both sexes. Forty-eight hours after halothane exposure fatty vacuolization of hepatocytes was present in all animals. Histologically identifiable hepatic necrosis occurred in 60% of the guinea pigs exposed, along with concomitant increases in SGPT. Approximately one half of these responding animals had extensive centrilobular necrosis, which was still present 96 hr after halothane exposure. Females of the inbred strain 2 and males and females of strain 13 were the most susceptible to halothane-induced hepatic necrosis whereas the inbred Hartley strain was almost totally refractory to necrosis. Outbred Amana and male inbred strain 2 animals exhibited an intermediate hepatotoxic response. Comparison of the halothane-associated hepatic lesion with that induced by anoxic/ischemic mechanisms, (exposure to low (8%) oxygen during 1.7% enflurane anesthesia) showed obvious differences in the morphology of the hepatic necrosis and the apparent time course of lesion development. This guinea pig model of halothane-associated hepatotoxicity appears to be superior to previous animal models in that no pretreatment of the guinea pigs is required, both sexes are affected, and the resulting hepatic lesion is more persistent.