An evaluation of tympanometric estimates of ear canal volume

The accuracy of tympanometric estimates of ear canal volume was evaluated by testing the following two assumptions on which the procedure is based: (a) ear canal volume does not change when ear canal pressure is varied, and (b) an ear canal pressure of 200 daPa drives the impedance of the middle ear transmission system to infinity so the immittance measured at 200 daPa can be attributed to the ear canal volume alone. The first assumption was tested by measuring the changes in ear canal volume in eight normal subjects for ear canal pressures between +/- 400 daPa using a manometric procedure based on Boyle's gas law. The data did not support the first assumption. Ear canal volume changed by a mean of .113 ml over the +/- 400 daPa pressure range with slightly larger volume changes occurring for negative ear canal pressures than for positive ear canal pressures. Most of the volume change was attributed to movement of the probe and to movement of the cartilaginous walls of the ear canal. The second assumption was tested by comparing estimates of ear canal volume from susceptance tympanograms with a direct measurement of ear canal volume adjusted for changes in volume due to changes in ear canal pressure between +/- 400 daPa. These data failed to support the second assumption. All tympanometric estimates of ear canal volume were larger than the measured volumes. The largest error (39%) occurred for an ear canal pressure of 200 daPa at 220 Hz, whereas the smallest error (10%) occurred for an ear canal pressure of -400 daPa at 660 Hz. This latter susceptance value (-400 daPa at 660 Hz) divided by three is suggested to correct the 220-Hz tympanogram to the plane of the tympanic membrane. Finally, the effects of errors in estimating ear canal volume on static immittance and on tympanometry are discussed.     

Impression-material foreign bodies of the middle ear and external auditory canal

Twenty-nine evaluable patients with endometrial cancer were treated with amonafide 300 mg/m2 for 5 consecutive days every 3 weeks. Two partial responses (8%) were seen. Hematologic toxicity was severe or life-threatening in 13 patients occurring as follows: leukopenia in 13 patients (45%); thrombocytopenia in 10 patients (34%); granulocytopenia in 13 patients (45%); and anemia in four patients (14%). In view of the low response rate and high toxicity, this dose schedule of amonafide does not warrant further investigation in endometrial cancer.     

The effects of increasing exchange volume and frequency on peritoneal dialysis adequacy

We investigated serum level of interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) using an enzyme-linked immunosorbent assay (ELISA) in 59 patients with systemic lupus erythematosus (SLE) and 16 healthy controls. We examined a possible association between serum levels of these cytokines and SLE activity, as well as correlation between IFN-gamma concentration and the level of TNF-alpha and IL-6 and also IL-6 and TNF-alpha. TNF-alpha and IL-6 were detectable in all 59 patients and normal individuals and their level was significantly higher in SLE patients than in the control group (p < 0.001 and p < 0.02, respectively). In contrast IFN-gamma was detectable in 23 (39%) patients and in only 3 (20%) healthy individuals. We found positive correlation between serum concentration of TNF-alpha and IL-6 with SLE activity and no such correlation with IFN-gamma. We also observed positive correlation between serum levels of IFN-gamma and TNF-alpha, IFN-gamma and IL-6 as well as TNF-alpha and IL-6. In conclusion, an increase in the serum levels of TNF-alpha and IL-6 may be useful markers for SLE activity.     

Feedback control of the auditory periphery: anti-masking effects of middle ear muscles vs. olivocochlear efferents

Both MEM and MOC systems are sound-evoked reflexes to the auditory periphery which can be elicited by sound in either ear. Both MEM and MOC systems can increase thresholds in the auditory periphery: the MEM system acts by stiffening the ossicular chain, the MOC system by decreasing outer hair cell amplification of sound-induced motion in the inner ear. MEM-induced attenuations are largest for low frequency stimuli, MOC-induced attenuations are largest for mid- to high-frequency sounds. Both MEM and MOC systems can have anti-masking effects. The MEM reflex can decrease the masking of high-frequency signals by low-frequency noise (i.e., the upward spread of masking). The MOC reflex is complementary in that it minimizes masking of high-frequency transient signals by high-frequency continuous noise. MEM anti-masking arises by reducing suppressive masking and can improve masked thresholds at high frequencies. MOC anti-masking arises by counteracting excitatory masking. It does not improve masked thresholds, but can improve the detectability of small suprathreshold intensity increments. Anti-masking effects of both MEM and MOC systems should be reduced in cases of sensorineural hearing loss.     

Magnetic resonance imaging and audiologic assessment of middle ear effusions in patients with nasopharyngeal carcinoma before radiation therapy

Recently, stent implantation has become the treatment of choice for patients with tracheobronchial stenosis due to malignant tumours, tuberculosis and recurrent stenosis following lung transplant. However, reports on this procedure in infants with congenital bronchial stenosis are extremely rare. We report successful stent implantation in an infant with congenital left bronchial stenosis followed by rapid improvement in his respiratory condition. CONCLUSION: The use of a stent in infants is still controversial because size mismatch will take place with growth. However, we believe that implantation of a metallic stent can be the preferred treatment of congenital bronchial stenosis even in small infants.     

Test-enhanced learning in a middle school science classroom: The effects of quiz frequency and placement.

Typically, teachers use tests to evaluate students' knowledge acquisition. In a novel experimental study, we examined whether low-stakes testing (quizzing) can be used to foster students' learning of course content in 8th grade science classes. Students received multiple-choice quizzes (with feedback); in the quizzes, some target content that would be included on the class summative assessments was tested, and some of the target content was not tested. In Experiment 1, three quizzes on the content were spaced across the coverage of a unit. Quizzing produced significant learning benefits, with between 13% and 25% gains in performance on summative unit examinations. In Experiments 2a and 2b, we manipulated the placement of the quizzing, with students being quizzed on some content prior to the lecture, quizzed on some immediately after the lecture, and quizzed on some as a review prior to the unit exam. Review quizzing produced the greatest increases in exam performance, and these increases were only slightly augmented when the items had appeared on previous quizzes. The benefits of quizzing (relative to not quizzing) persisted on cumulative semester and end-of-year exams. We suggest that the present effects reflect benefits accruing to retrieval practice, benefits that are well established in the basic literature. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Petrous bone tumors: primary non-Hodgkin lymphoma of the inner ear canal and cerebellopontile angle

BACKGROUND: We report about a primary Non-Hodgkin Lymphoma (NHL) of the internal auditory canal. The only previously known manifestations of a NHL in the temporal bone have been infiltrations or hemorrhagic complications due to a late manifestation or advanced systemic disease. Involvement of both temporal bones is typical. CLINICAL CASE: The 60-year-old female patient complained of an acute one-sided deafness, accompanied by a high-pitched tinnitus, rotating vertigo, and paralysis of the left half of the face. RESULTS: We found a deafness in the left ear, spontaneous nystaxis, which was interpreted as a deficiency in excitement of the vestibular organ, and a complete peripheral facial paralysis. Diagnostic imaging studies revealed a large, intrameatal solid mass in the temporal bone, measuring 1.2 x 0.8 cm. Histologic examination after translabyrinthine tumor removal demonstrated a centroblastic Non-Hodgkin Lymphoma. The following extensive interdisciplinary staging examination showed no other tumor manifestations; the CSF analysis was negative. CONCLUSIONS: The uniqueness of this case lies in the detection of a primary nongeneralized centroblastic lymphoma of the internal auditory canal. In contrast to infiltrations of systemic NHL in the same location, in which the advanced disease is responsible for the bad prognosis, this isolated lymphoma of the internal auditory canal seems analogous to extranodal MALT Lymphomas with a better prognosis. The primary extranodal NHL of the temporal bone, not reported in previous studies, is discussed with regard to clinical symptoms, differential diagnoses, and therapeutic strategies.     

浅谈大中型工程概算调整

根据工程实践，对工程概算调整的编制方法和工作重点进行了探讨。     

Anomalous vessel in the middle ear: the role of CT and MR angiography

The pyrazolo[3,4-b]pyridine derivatives 3 could be prepared by condensing compounds 1 with the 3-aminopyrazolone derivative 2. The pyrazolo[5,2-b]-1,3-oxazine derivative 11 and polyfunctionally substituted 1,4-dihydropyridines 15, 18 were also synthesized. Some of the obtained compounds were tested for their antimicrobial activity.     

Pretransformation effects of localized soft modes on neutron scattering,acoustic attenuation,and Mössbauer resonance measurements

The localized soft mode model of martensitic nucleation is used to predict pretransformation effects of such regions on inelastic neutron scattering, ultrasonic acoustic attenuation and Mössbauer resonance absorption. The theoretical predictions are compared with the available experimental data.     

Active electronic cochlear implants for middle and inner ear hearing loss--a new era in ear surgery. I: Basic principles and recommendations on nomenclature

Hearing aids have fundamental disadvantages: (1) stigmatization of the patient; (2) the sound is often found to be unsatisfactory due to the limited frequency range and undesired distortion; (3) in many patients, the ear canal fitting device generally necessary leads to an occlusion effect; (4) acoustic feedback when amplification is high. Conventional hearing aids transmit sound into the ear canal via a small microphone. Sound has the disadvantage of requiring high output sound pressure levels for its transmission. This along with the necessary miniaturization of the loudspeaker as well as the resonances and reflections in the closed ear canal contribute to the disadvantages mentioned. In contrast, implantable hearing aids do not make sound signals but micromechanical vibrations. An implantable hearing aid has an electromechanical transducer instead of the loudspeaker of a conventional hearing aid. The hearing signal does not leave the transducer as sound but as a mechanical vibration which is directly coupled to the auditory system bypassing the air. This implantable hearing aid is either coupled to the tympanic membrane, the ossicular chain, the perilymph of the inner ear, or the skull. An implantable hearing aid is expected to have: 1 Better sound fidelity than a hearing aid 2 No ear canal fitting device, free ear canal 3 No feedback 4 Invisibility Requirements on electronic hearing implants designed for patients with conductive hearing loss differ from those on implants for sensorineural hearing loss. Conductive hearing loss requires the implant to replace the impedance transformation, thus being an impedance transformation implant (ITI). In various respects, the demands on an ITI are lower than the demands on an electronic hearing aid for patients with sensorineural hearing loss. The latter are mostly patients with a failure of the cochlea amplifier (CA). A damage to the CA is clinically discernible by a positive recruitment and loss of otoacoustic emissions (OAE). Since these patients form the majority of cases with sensorineural hearing loss, an active hearing implant for such patients should partially replace the function of the CA. Therefore, the suggestion is to refer to a CAI (cochlea amplifier implant). The implant expressions ITI (for patients with conductive hearing loss) and CAI (for patients with sensorineural hearing loss) used in this context allow nomenclatural association with the CI (cochlear implant) for complete inner ear failure as well as with the BSI (brainstem implant) in the case of hearing nerve failure.     

Auditory stream segregation by musical timbre: Effects of static and dynamic acoustic attributes.

Two experiments examined the influence of timbre on auditory stream segregation. In Experiment 1, listeners heard sequences of orchestral tones equated for pitch and loudness, and they rated how strongly the instruments segregated. Multidimensional scaling analyses of these ratings revealed that segregation was based on the static and dynamic acoustic attributes that influenced similarity judgments in a previous experiment (P. Iverson & C. L. Krumhansl, 1993). In Experiment 2, listeners heard interleaved melodies and tried to recognize the melodies played by a target timbre. The results extended the findings of Experiment 1 to tones varying in pitch. Auditory stream segregation appears to be influenced by gross differences in static spectra and by dynamic attributes, including attack duration and spectral flux. These findings support a Gestalt explanation of stream segregation and provide evidence against a peripheral channel model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of hyperoxia on in vitro growth of rabbit middle ear epithelium and auditory meatal epithelium

As stated in the conclusion, "life is a thing of macromolecular cohesion in salty water." This brief historical overview shows that "compensatory" organic osmolytes take an essential place in this cohesion. It reviews the major steps of the study of these compounds over more than 100 years, from the early beginnings of 1885 until now, showing some of its fascinating developments and ending on the idea that the most fascinating is still to come. This study can be taken as an example of the richness of the comparative approach.     

Effects of PEEP on respiratory mechanics are tidal volume and frequency dependent

Later steps of carotenoid biosynthesis catalyzed by cyclase enzymes involve the formation of alpha, beta, and kappa-rings. Examination of the primary structure of lycopene beta-cyclase revealed 55% identity with that of antheraxanthin kappa-cyclase. Recombinant lycopene beta-cyclase afforded only beta-carotene, while recombinant antheraxanthin kappa-cyclase catalyzed the formation of beta-carotene from lycopene as well as the conversion of antheraxanthin into the kappa-carotenoid capsanthin. Since the formation of beta- and kappa-rings involves a transient carotenoid carbocation, this suggests that both cyclases initiate and/or neutralize the incipient carbocation by similar mechanisms. Several amine derivatives protonated at physiological pH were used to examine the molecular basis of this phenomenon. The beta-and kappa-cyclases displayed similar inhibition patterns. Affinity or photoaffinity labeling using p-dimethylamino-benzenediazonium fluoroborate, N,N-dimethyl-2-phenylaziridinium, and nicotine irreversibly inactivated both cyclase enzymes. Photoaffinity labeling using [3H]nicotine followed by radiosequence analysis and site-directed mutagenesis revealed the existence of two cyclase domains characterized by the presence of reactive aromatic and carboxylic amino acid residues. We propose that these residues represent the "negative point charges" involved in the coordination of the incipient carotenoid carbocations.