Pressure chamber tests of eustachian tube function document lower efficiency in adults with colds when compared to without colds.

Conclusions: Fractional gradient equilibrated (FGE) for ears with applied positive but not negative middle ear (ME)-ambient pressure gradients is highly sensitive to a cold-like illness (CLI).

Objective: The sequential development of eustachian tube (ET) dysfunction, ME under-pressure, and otitis media (OM) characterizes many children during a CLI. If linked, OM burden would be lessened by interventions that promote/preserve good ET function during a CLI.

Eustachian tube function in young children without a history of otitis media evaluated using a pressure chamber protocol.

Conclusions: Protocol limitations were identified and accounted for in the analysis. Percent gradient equilibrated (PGE) was affected by driving gradient direction in a similar manner to other efficiency measures. A finer resolution of possible age-related changes in eustachian tube opening efficiency is expected with the application of more sophisticated statistical models to the complete dataset at study end.

A method to assess the accuracy of sonotubometry for detecting Eustachian tube openings.

Sonotubometry is a simple test for Eustachian tube (ET) opening during a maneuver. Different sonotubometry configurations were suggested to maximize test accuracy, but no method has been described for comparing sonotubometry test results with those for a definitive measure of ET opening. Here, we present such a method and exemplify is use by an accuracy assessment of a simple sonotubometry configuration.

Eustachian tube opening measured by sonotubometry is poorer in adults with a history of past middle ear disease.

Objective: Test the hypothesis that active Eustachian tube opening efficiency as measured by sonotubometry is higher in adults with no extant middle-ear disease and no history of previous otitis media (Group-1) when compared to adults with no middle-ear disease but a positive history for otitis media (Group-2).

Methods: Eustachian tube function for 1 ear of 33 otherwise healthy adult subjects, 16 assigned to Group-1 and 17 to Group-2, was tested by sonotubometry using a standard protocol. For each test, the sound envelopes for 3 swallows were abstracted independently by 2 observers from the data stream and 7 descriptive parameters related to sound envelope "shape" were calculated.

Transmucosal O2 and CO2 exchange rates for the human middle ear.

Objective: Estimate the transmucosal CO(2) and O(2) rate-constants for adult middle ears (MEs).

Methods: Ten adults with healthy MEs had a unilateral myringotomy. A custom-fitted acrylic mold with a valved line to a mass spectrometer (MS) and central tube coupled to a 3-way valve and connected to a pressure transducer (the probe) was sealed with adhesive glue within the ipsilateral ear-canal.

CO(2) gas exchange across the human tympanic membrane is not appreciably affected by pathology.

Past in vivo studies in humans showed that the tympanic membrane (TM) is permeable to physiological gases. Animal studies show that transTM CO(2) conductance is increased by TM pathology. The objective of the study was to determine if transTM CO(2) exchange in humans is affected by atrophic and sclerotic pathologies.

Interaction of pneumococcal phase variation, host and pressure/gas composition: virulence expression of NanA, HylA, PspA and CbpA in simulated otitis media.

Streptococcus pneumoniae, a leading cause of otitis media (OM), adapts to the host environment and undergoes spontaneous intra-strain phase variations in colony morphology. Transparent (T) phase variants are more efficient in colonizing the nasopharynx while the opaque (O) phase variants exhibit greater virulence during systemic infections. We recently demonstrated that T phase variants exhibited a higher growth rate and greater epithelial adherence and destruction than did O phase variants during interactions with human middle ear (ME) epithelial cells.

Interaction of phase variation, host and pressure/gas composition: pneumococcal gene expression of PsaA, SpxB, Ply and LytA in simulated middle ear environments.

Objective: Streptococcus pneumoniae, a leading cause of otitis media (OM), undergoes spontaneous intra-strain variations in colony morphology. Transparent (T) variants are more efficient in colonizing the nasopharynx while opaque (O) variants exhibit greater virulence during systemic infections. This study was intended to delineate the underlying molecular mechanisms by which the predominant S.

Repair of the tympanic membrane with urinary bladder matrix.

Objectives/hypothesis: To test urinary bladder matrix (UBM) as a potential treatment for tympanic membrane (TM) healing and regeneration.

Study Design: This prospective pilot study was designed to provide both qualitative and semiquantitative assessment of temporal and spatial healing events in the chinchilla model of chronic TM perforations with and without UBM patching.

Methods: Bilateral myringotomies were performed and repeated as necessary to create subtotal perforations over an 8-week period.

Interaction of pneumococcal phase variation and middle ear pressure/gas composition: an in vitro model of simulated otitis media.

Streptococcus pneumoniae, a leading cause of otitis media (OM), undergoes spontaneous intra-strain variations in colony morphology. Transparent (T) variant is more efficient in colonizing the nasopharynx while the opaque (O) variant exhibits greater virulence during systemic infections. We hypothesized that changes in middle ear (ME) gas pressure/composition during Eustachian tube (ET) dysfunction and the treatment of that dysfunction, e.

Directional asymmetry in the measured nitrous oxide time constant for middle ear transmucosal gas exchange.

Objectives: Simple, 2-compartment mathematical models of middle ear (ME) transmucosal gas exchange reproduce observed ME pressure behavior. These models require input of an experimentally determined, lumped-parameter exchange constant for each represented gas species. Previous model applications assumed directional asymmetry for those parameters, which has not been experimentally validated.

Nasal prostaglandin challenge increases N2O exchange from blood to middle ear.

Nasal inflammation (NI) resulting from allergy or virus infection is causally associated with otitis media. Impaired Eustachian tube (ET) function consequent to NI may mediate this relationship. Moreover, the functional demand placed upon the ET for gas supply may be increased by NI, a hypothesis tested here.

Gas diffusion across the tympanic membrane in chinchillas: effect of repeated perforations.

Objective: Earlier studies documented a slow diffusion of gas across the tympanic membrane (TM) in humans and animals. However, structural changes caused by repeated TM perforations could affect gas diffusion rates. This possibility was evaluated using a chinchilla model.

Tympanometry accurately measures middle ear underpressures in monkeys.

Tympanometry is useful for evaluating middle ear (ME) status, but its accuracy in estimating true ME pressure has been questioned. We evaluated the accuracy of tympanometry in 6 monkeys. Direct application and measurement of ME pressure were achieved with a probe introduced into the mastoid antrum, and tympanometry was done over a large range of applied ME pressures.

Middle ear gas exchange in the air phase.

Objective: The rate of gas exchange between the tympanum and mastoid is important for middle ear pressure regulation. The best-studied model of middle ear pressure regulation is the cynomolgus monkey. The aim of this study was to determine the time required for the equilibration of tympanum and mastoid partial pressures for two inert gases, argon and helium, in cadaveric cynomolgus monkey middle ears.

Rate of nitrous oxide exchange across the middle ear mucosa in monkeys before and after blockage of the mastoid antrum.

Objectives: We tested the hypothesis that mastoid volume buffers the rate of change in middle ear pressure caused by transmucosal, inert gas exchange.

Study Design: Twelve monkeys were randomly assigned to group 1 or group 2. Right ears of group 1 had sham surgery and of group 2 had obstruction of the mastoid antrum.

Middle ear pressure change during controlled breathing with gas mixtures containing nitrous oxide.

The change in middle ear pressure while breathing gas mixtures containing N(2)O was studied in four monkeys. At each of three experimental sessions, monkeys were anesthetized, acclimated for 60 min, breathed with room air for 60 min, and then breathed with 5, 10, or 20% N(2)O for 60 min. Middle ear pressure, rectal temperature, and vital signs were recorded throughout.