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Biomedical subjects

S S Chandrasekhar

Publications and source records attributed to S S Chandrasekhar.

13 recordsLinked to original sources
PubMed2001

Dosage regimens of intranasal aerosolized surfactant on otitis media with effusion in an animal model.

OBJECTIVE: To determine optimal dosage regimens of intranasal metered dose aerosolized surfactant with and without other medications in the treatment of otitis media with effusion (OME). STUDY DESIGN: Resolution of experimental OME in gerbils was determined based on otomicroscopy and tympanometry. Experimental intranasal drugs were: surfactant, surfactant with betamethasone, surfactant with phenylephrine, and a normal saline solution placebo. Medications were administered once or twice daily via a metered dose inhaler. RESULTS: For twice-daily dosing, mean days to OME resolution were 8.5 for the aerosolized surfactant, 6.3 for the surfactant with betamethasone, 18.7 for the surfactant with phenylephrine, and 16 each for control and placebo. Resolution with the once-daily dosage was longer for all conditions. Results were comparable using tympanometry. CONCLUSION: OME resolved faster than the natural course when treated with intranasal surfactant with and without steroids. Twice-daily dosing was statistically superior. SIGNIFICANCE: This study reiterates the effectiveness of OME treatment with an aerosolized synthetic surfactant with and without steroids and establishes a superior twice-daily dosage schedule.

Acoustic Impedance Tests↗
PubMed2001

Intratympanic dexamethasone for sudden sensorineural hearing loss: clinical and laboratory evaluation.

OBJECTIVE: To discuss the value of intratympanic dexamethasone (IT-DEX) perfusion for sudden sensorineural hearing loss (SSNHL), clinically and in an animal model. STUDY DESIGN: Retrospective case review of 10 patients with SSNHL treated with IT-DEX. The findings are correlated with this institution's previous findings from a study of IT-DEX in guinea pigs. SETTING: Ambulatory tertiary otologic referral center. PATIENTS: Sequential patients with SSNHL who chose IT-DEX treatment. INTERVENTIONS: Dexamethasone 0.5 mg was injected transtympanically and bathed the round window for 20 minutes. Animal study: 79 ears were randomized into five groups: control, IT-DEX versus intravenous (IV)-DEX, IT-DEX with histamine, IT-DEX with hyaluronic acid, and IT-DEX with dimethylsulfoxide. MAIN OUTCOME MEASURES: Clinical study: postprocedure audiometry. Animal study: perilymph steroid concentration. RESULTS: IT-DEX results in significant hearing improvement and in significantly higher perilymph concentration of steroid than IV-DEX. CONCLUSIONS: IT-DEX is an appropriate treatment option for the treatment of SSNHL. Further study of dosages and frequency of administration is warranted.

Administration, Topical↗
PubMed2001

Recurrent glomus tumor of the pinna: report of a case.

We describe a rare case of a glomus tumor of the pinna. The lesion produced a brief but sharp pain that occurred spontaneously, intermittently, and upon tactile stimulation. Surgical excision with wide margins was successful. We believe this to be only the third case of a glomus tumor of the auricle that has been reported in the literature.

Adult↗
PubMed2000

Dexamethasone pharmacokinetics in the inner ear: comparison of route of administration and use of facilitating agents.

There is growing otologic interest in treating inner ear disorders, such as sudden sensorineural hearing loss and acute or unremitting Meniere's disease, with intratympanic dexamethasone (IT-DEX). Although anecdotally reported, there are no scientific clinical papers and few prior laboratory research publications on the subject. This study compares perilymph dexamethasone concentrations after systemic and intratympanic administration and assesses the role of 3 potential transport facilitators of IT-DEX into perilymph. Forty guinea pigs (79 ears) were randomly separated into 5 groups. Dexamethasone levels were measured by radioimmunoassay. IT-DEX resulted in higher perilymph steroid levels than intravenous dexamethasone (P < 0.05). Histamine facilitator resulted in significantly higher perilymph steroid levels than IT-DEX alone (P < 0.05). Neither hyaluronic acid nor dimethylsulfoxide was a potent facilitator. This study demonstrates that IT-DEX administration results in superior perilymph levels within 1 hour of administration and does not result in systemic absorption. Histamine is a potent facilitating agent. The clinical implications are considerable.

Administration, Topical↗
PubMed2000

Intranasal surfactant aerosol therapy for otitis media with effusion.

OBJECTIVE: To determine the effect of surfactant alone and with other medications delivered intranasally as a metered dose inhaler (MDI) aerosol on the resolution of experimentally induced otitis media with effusion (OME). BACKGROUND: Eustachian tube dysfunction is a primary factor in the pathogenesis of OME. Intranasal surfactant via MDI has been shown in this laboratory to reduce passive opening pressure of the eustachian tube in normal gerbils and mice. STUDY DESIGN: OME was developed in 35 gerbils by transtympanic injection of 10 microg lipopolysaccharide from Klebsiella pneumoniae. Pretreatment otomicroscopy and tympanometry were performed to exclude pre-existing middle ear disease, and postinfection evaluations were performed on alternate days for a period of 30 days. Five animals received no treatment (control group); four were treated with propellant only (placebo); seven received surfactant alone; eight received surfactant and betamethasone; and six received surfactant with phenylephrine. All medications were sprayed intranasally as an aerosolized MDI and administered daily from postinfection day 2 onward. RESULTS: OME resolved after 16.0 +/- 0.44 days (mean + SD) in controls. There was no difference seen in the placebo or the surfactant with phenylephrine groups. Treatment with surfactant yielded resolution in 10.57 +/- 0.37 days; this was reduced to 8.57 +/- 0.37 days with surfactant plus betamethasone. These differences are statistically significant. There was no recurrence of OME in any group. CONCLUSION: This study demonstrates that using an aerosolized MDI surfactant with and without betamethasone decreases the duration of OME in this in vivo gerbil model.

Administration, Intranasal↗
PubMed1996

Endoscopic closure of the eustachian tube for repair of cerebrospinal fluid leak.

Techniques to repair cerebrospinal fluid (CSF) leak through the eustachian tube (ET) include temporary or permanent CSF diversion; middle fossa craniotomy and packing of the ET from above; and packing of the ET from behind, through the middle ear. We report a case of endoscopic closure of the ET in the nasopharynx (the front). A 26-year-old woman underwent a translabyrinthine removal of a 4.5-cm vestibular schwannoma. One year later, she developed CSF rhinorrhea and meningitis. Attempts at control of this leak included traditional approaches mentioned previously (shunting, middle fossa, middle ear packing). The leak recurred 2-3 months after each procedure. An endoscope was used transnasally to expose the ET orifice, which was incised, inverted, and cauterized. She has remained free of leak for 1 year. Our success in this difficult case suggests that this is a useful procedure for treatment of CSF rhinorrhea originating in the posterior fossa. Greater experience is needed to verify its long-term effectiveness and utility as a primary procedure for the treatment of CSF rhinorrhea.

Adult↗
PubMed1995

Pediatric tympanoplasty. A 10-year experience.

OBJECTIVES: To determine if the age of the child is a factor in healing after tympanoplasty and to find other factors that affect the outcome in these patients. DESIGN: Case series by retrospective otological chart review. SETTING: A group private practice otology and neuro-otology referral center. PATIENTS AND OTHER PARTICIPANTS: A consecutive sample of all patients younger than 20 years who had tympanoplasty performed at the House Ear Clinic between January 1, 1983, and January 1, 1993. The 318 patients, who had had 381 ears operated on, were separated into four age groups: younger than 7 years, 7 to 8 years, 9 to 12 years, and 13 to 19 years. The 268 patients who had follow-up examinations for 6 months or longer after tympanoplasty are grouped in the same age categories for outcomes analysis. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Preoperative and postoperative audiometric data and otologic examination at the final follow-up examination. Results are reported for hearing, healing, and "success," which combines hearing and healing and is defined as an intact graft with a postoperative air-bone gap of less than 25 dB. RESULTS: The operation resulted in an intact graft in 92.5% of ears and a postoperative air-bone gap less than 25 dB in 84% of ears. Success was achieved in 81% of ears. No difference in outcome was observed among the four age groups. Success was negatively affected by mastoidectomy, previous tympanoplasty, and use of total ossicular replacement prosthesis ossiculoplasty; perhaps by the number of previous myringotomy and tubes; but not by age, status of the contralateral ear, middle ear discharge, or fellow as primary surgeon. CONCLUSION: Tympanoplasty can be safely and effectively performed in children.

Adolescent↗
PubMed1995

Surgery of congenital aural atresia.

The treatment of congenital aural atresia has changed in recent years. Better imaging capabilities, the development of tympanoplasty techniques, modification of mastoid dissection, and facial nerve monitoring have resulted in greater patient benefit with less patient risk. Success rates continue to be high, and the incidence of complications has decreased. A series of cases was reported in 1985, and now the authors review 92 congenital aural atresiaplasties performed over the following 9 years. Closure of the air-bone gap to less than 30 dB was achieved in 60% of primary surgeries and 54% of revisions. The most common complications were external auditory canal stenosis and lateralization of the tympanic membrane. External auditory canal stenosis due to bony regrowth was seen in 12% of primary cases and 11.5% of revisions; soft tissue stenosis was seen in 10% of primaries and 4% of revisions. Tympanic membrane lateralization was seen in 9% of primary surgeries and in 15% of revisions. Carbon dioxide and argon lasers (HGM Medical Laboratories, Salt Lake City, Utah) and Merocel stenting wicks with split-thickness skin grafting were used to try to improve long-term hearing outcome and decrease postoperative external auditory canal stenosis. With meticulous surgical technique by an experienced otologic surgeon and appropriately selected patients, this problem can be managed effectively.

Adolescent↗
PubMed1995

Utility of auditory brainstem response audiometry in diagnosis of acoustic neuromas.

Auditory brainstem response (ABR) audiometry is said to be 90% sensitive in the diagnosis of acoustic neuromas. Since gadolinium-DTPA was introduced, magnetic resonance imaging (MRI) is capable of detecting acoustic neuromas as small as 3 mm. Early diagnosis is important, because hearing can frequently be preserved with resection of tumors smaller than 2 cm. At the same time, cost-containment has become a pressing issue in medicine. Auditory brainstem response, although considerably less expensive than MRI, may not be as sensitive as previously thought, particularly for small tumors. Of 753 acoustic neuromas treated at the House Ear Clinic from January 1988 through March 1993, 197 had ABR data available. The 98 males and 99 females ranged in age from 13 to 78 years with a mean of 48 years. The overall sensitivity of ABR was 92.3% using an interaural latency difference for wave V of more than 0.2 ms, and was 81.6% using waveform morphology. There was a statistically significant difference in sensitivity with respect to tumor size. Auditory brainstem response interaural latency difference sensitivity ranged from 100% in tumors larger than 3.0 cm to 83.1% in tumors 1.0 cm or smaller. Waveform morphology was abnormal in 100% of tumors larger than 2.0 cm but in only 76.5% of tumors 1.0 cm or smaller.

Adolescent↗
PubMed1992

Histopathologic and ultrastructural changes in the temporal bones of HIV-infected human adults.

Acquired immunodeficiency syndrome (AIDS) is a devastating disease that is affecting the human population in epidemic numbers. Patients with AIDS are known to have a significant incidence of otologic disease, including hearing loss, vertigo, tinnitus, otalgia, and infection with unusual pathogens. There has been no previous work on the histopathology of this disease. Ten temporal bones from five patients who were seropositive for the human immunodeficiency virus (HIV), the causative retrovirus of AIDS, were obtained. Seven specimens were analyzed using light microscopic techniques. Electron microscopy was performed on selected areas of pathology. A myriad of pathologic findings was seen, including severe petrositis with marrow replacement, mastoiditis, otitis media, ossicular destruction, precipitations in the perilymphatic and endolymphatic spaces of the vestibule and of the semicircular canals, and subepithelial elevation of the neurosensory epithelium of the saccule and utricle. The organ of Corti was relatively free of pathologic change. Many of the otologic symptoms encountered in these patients can be explained by the findings in this study. Further investigation using light and electron microscopy, and immunohistochemical techniques, is urged.

AIDS-Related Complex↗
PubMedDate not supplied

Otologic and audiologic evaluation of human immunodeficiency virus-infected patients.

PURPOSE: To quantify the incidence of ear disease in patients infected with human immunodeficiency virus (HIV). MATERIALS AND METHODS: This is a descriptive case series of HIV-positive patients, with data collected using an otologic questionnaire. otologic examination, audiologic evaluation, and chart review. The study was performed at an urban University Hospital's outpatient Infectious Disease and Otolaryngology clinics. A consecutive sample of 50 HIV-infected patients volunteered for this study. Ten subjects refused. Almost all patients received public assistance for medical care. Descriptive results were tabulated. Audiometric data were analyzed for ear, Centers for Disease Control (CDC) group, otologic complaint, and age effects. Data were compared with established norms. RESULTS: Twenty-three men and 27 women with a mean age of 40 years and mean duration of HIV disease of 3.5 years were studied. Eighteen percent of patients were in category CDC-A, 38% in CDC-B, and 44% in CDC-C. Otologic complaints were more prevalent than expected: 34% of patients reported aural fullness, 32% dizziness, 29% hearing loss, 26% tinnitus, 23% otalgia, and 5% otorrhea. Results of the neuro-otologic examination were abnormal in 33%. Tympanometric examination was abnormal in 21%. A significant degree of high-frequency sensorineural hearing loss was observed. CDC-B and CDC-C patients had worse hearing than CDC-A patients at 3 frequencies. Patients who complained of hearing loss had significantly worse otoacoustic emission results and hearing results than patients who did not, at all frequencies except 1,000 Hz. Patients in their 30s had better hearing in the speech frequencies than did all other patients. CONCLUSIONS: Ear disease affects up to 33% of HIV-infected patients. Otitis media is a frequent finding. Sensorineural hearing loss is more severe in patients with more severe HIV infection. Patients with ear complaints have demonstrable otopathology. Continuation of this preliminary descriptive work is necessary.

Adult↗