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Biomedical subjects

P A Schachern

Publications and source records attributed to P A Schachern.

At least 19 recordsLinked to original sources
PubMed2001

Pattern changes of mucin gene expression with pneumococcal otitis media.

OBJECTIVE: mucins, known to be important components of the mucociliary transport system in the middle ear and Eustachian tube, are subject to changes under inflammatory conditions. Which mucin genes are up-regulated or activated during an inflammatory reaction of the middle ear and Eustachian tube, however, is poorly understood. The purpose of this study was to characterize mucin gene expression in middle ears and Eustachian tubes with pneumococcal ear infection. METHODS: sixteen rats received intrabullar inoculation of Streptococcus pneumoniae type 6A at 2.5x10(6) colony forming units (CFU). Four animals were sacrificed on days 1, 3, 7, and 14, respectively. The profile of mucin gene expression in the middle ear and Eustachian tube was examined by reverse transcription polymerase chain reaction (RT-PCR) at the above time points. Sixteen rats that received intrabullar inoculation of phosphate-buffered saline (PBS) served as controls. RESULTS: the Muc2 mucin gene was expressed in middle ear mucosa of the control rats. Following pneumococcal inoculation, Muc1-Muc5 mucin genes were expressed in the middle ear mucosa in a time-dependent manner. In the Eustachian tube, the Muc2, Muc4 and Muc5 mucin genes were expressed in both control and pneumococcal inoculation groups. CONCLUSION: Muc1, Muc3, Muc4, and Muc5 mucin genes were activated in the middle ear mucosa by pneumococci, which may contribute to hyper-production of mucin in acute pneumococcal otitis media.

Animals↗
PubMed2001

The development of the middle ear in neonatal chinchillas II. Two weeks to adulthood.

Studies of auditory function in the human neonate indicate adult-like hearing sensitivity, mature cochlear function and well-developed responses in the auditory pathway. Paradoxically, measurements of middle ear function are characterized by responses that would be interpreted as abnormal in older subjects. Consequently, there is not an accepted clinical test for middle ear disease in the newborn population. Like human neonates, chinchillas have normal hearing sensitivity at birth, but middle ear function tested by multifrequency tympanometry is abnormal compared to the adult. A previous study from our laboratory indicated that the newborn chinchilla middle ear is free of mesenchyme and other debris. Over the first 2 weeks of life there were no significant changes in tympanic membrane thickness and diameter, tympanic membrane to promontory distance and stapes footplate length. There were small changes in mastoid bulla area and perimeter and in mastoid bulla bone thickness. The most striking difference between the newborn and adult temporal bone was in bone composition, the newborn bone having a less dense, spongy appearance. Impedance characteristics of the newborn chinchilla ear, measured by multifrequency tympanometry, were abnormal relative to adult animals and did not change over the first 2 weeks of life. This investigation is an extension of the previous study, designed to better understand the relationship between middle ear function, hearing sensitivity and the structural changes of the newborn chinchilla middle ear. Twenty animals, aged 2-8 weeks, were studied. Additional adult animals were used as controls. Middle ear function was assessed by a wideband reflectance impedance system. Hearing sensitivity was measured by auditory brainstem response in 2- and 8-week-old animals. Structural characteristics of the temporal bone were analyzed using histopathologic preparations. There was an orderly progression in middle ear impedance and reflectance characteristics as the chinchilla ear matured from 2 to 8 weeks of age. At 8 weeks of age, impedance and reflectance patterns approached, but did not match, those of the adult animal. Hearing sensitivity was unchanged throughout this maturational period. Finally, histological analysis demonstrated no age-related changes in distance from the tympanic membrane (TM) to the promontory and in stapes footplate length. There was a small significant decrease in the TM thickness from 2 weeks to adulthood. The most significant developmental changes were a reduction in mastoid bone thickness and concomitant increases in the perimeters and areas of the middle ear and posterior bulla.

Acoustic Impedance Tests↗
PubMed2001

Wideband reflectance tympanometry in chinchillas and human.

Wideband reflectance tympanometry was performed on twelve chinchillas ears. The complex input impedance of the middle ear, multifrequency admittance tympanograms, reflectance patterns (reflectance versus frequency), and reflectance tympanograms (reflectance versus ear-canal air pressure) were analyzed and compared to human data. The complex impedance of the chinchilla ear has a lower stiffness reactance at low frequencies, a higher mass reactance at high frequencies, and a lower resistance compared to the human. Multifrequency admittance tympanograms from chinchillas follow the same sequence of patterns as humans for low frequencies (<2 kHz). At higher frequencies tympanograms from both species are poorly organized and do not follow a consistent sequence of patterns. Reflectance patterns of chinchillas and humans are different. However, both species show high reflectance at low frequencies, regions of lower reflectance in mid-frequencies (2-6 kHz), and high reflectance at high frequencies (>8 kHz). Reflectance tympanograms for the two species show a single, centrally located minimum at low frequencies (<2 kHz) and are substantially different at higher frequencies. Results are shown for two animals that underwent eustachian tube obstruction. Reflectance patterns obtained with different ear-canal air pressures are substantially different. Reflectance results at any single ear-canal pressure (including ambient pressure) do not completely characterize the effects of middle-ear pathology.

Acoustic Impedance Tests↗
PubMed2001

Stapes mobilization in otosclerosis.

We performed a retrospective chart study (including surgeon's notes and audiometric results) and an analysis of the archival temporal bones from a patient who had undergone surgery for stapes mobilization in both ears. The stapes footplate was submerged into the vestibule on the right (as a complication of surgery) and absent on the left. One interesting finding was that the patient's hearing had improved on the right despite the presence of the depressed footplate and that the air-bone gap had widened on the left despite the absence of complications on that side.

Aged↗
PubMed2000

Histopathologic features of the temporal bone in patients with cystic fibrosis.

OBJECTIVES: To investigate the lower than expected incidence of otitis media in patients with cystic fibrosis (CF) through histopathologic evaluation of temporal bones and to document pathologic findings in the inner ears of patients with CF who received long-term administration of antibacterial and diuretic agents. DESIGN: Clinical records of patients who died of CF were reviewed. Their temporal bones were sectioned, stained with hematoxylin-eosin, and examined histologically. Additional sections were stained with Alcian blue and periodic acid-Schiff for comparison of goblet cell densities from middle ears and auditory tubes of patients with CF with those of control temporal bones. Results were analyzed using the t test. SUBJECTS: Twenty-one temporal bones from 11 patients with CF and 13 bones from 8 age-matched patients without CF were selected. RESULTS: All temporal bones with CF had well-pneumatized mastoids. Temporal bones from 2 patients (3 ears) revealed histological findings of chronic otitis media with effusion. There was a statistically significant reduction in the density of goblet cells in the medial (P = .002) and lateral (P = .05) walls in patients with CF who had no otitis media histologically compared with control temporal bones. Two patients with CF who had otitis media had increased densities of goblet cells. Inner ear damage, due to ototoxic drugs, was seen in most of the temporal bones from patients with CF. CONCLUSION: Low densities of goblet cells in temporal bones with CF may contribute reduced amounts of viscous mucus, which can lead to a low incidence of otitis media.

Adolescent↗
PubMed2000

Metastases to temporal bones from primary nonsystemic malignant neoplasms.

OBJECTIVES: To compare histopathological and clinical findings of metastasis to the temporal bone with previous reports and to determine the prevalence of these metastases in patients with nonsystemic cancer. STUDY DESIGN: Retrospective. METHODS: Autopsy records of 864 patients were screened to select those with primary nondisseminated malignant neoplasms. These were evaluated histopathologically for metastasis to and site of involvement within the temporal bone, and histological characteristics of the tumor. Clinical records and autopsy reports were reviewed for demographic data, clinical course, otologic and vestibular manifestations, site of primary and its histological features, extent of metastasis, and mode of spread. RESULTS: Of 212 patients with primary nondisseminated malignant neoplasms, 47 had metastases to the temporal bone (76 temporal bones). Twenty different primary tumors had metastasized, most commonly breast cancer. Hearing loss was the most common otologic symptom (seen in 19 patients [40%]), while 17 (36%) had no otologic or vestibular symptoms. Temporal bone involvement was bilateral in 29 patients (62%). Most metastases to the temporal bone demonstrated hematogenous spread in 58 temporal bones (76.7%), and petrous apex was the most common site of metastases in 63 temporal bones (82.9%). Temporal bone metastases were not observed in cases where the primary tumor was adequately treated. CONCLUSIONS: In the largest series to date, we found temporal bone metastases more frequently than previously reported. Absence of temporal bone involvement in cases in which the primary tumor was adequately treated stresses the need for early management of cancer. Metastatic disease must be considered as a cause of hearing loss in patients with a history of malignant neoplasm.

Adolescent↗
PubMed2000

Facial neuroma in the internal auditory canal.

Authors presented two cases of facial neuromas in the internal auditory canal, one without facial palsy and the other with facial palsy. In both cases neuromas were occult and undiagnosed. Although in the first case neuroma was greater than the other, facial palsy was not developed. The mechanism of the facial palsy due to neuromas could not be clearly clarified.

Aged↗
PubMed2000

Tympanic membrane and middle ear pathologic correlates in mucoid otitis media.

OBJECTIVE: The goal of this study was to correlate tympanic membrane (TM) and middle ear (ME) pathologies in mucoid otitis media (MOM). METHODS AND MATERIAL: Forty ears with MOM and 56 control ears were retrospectively evaluated for TM and ME pathologies. Comparisons of TM thicknesses in MOM versus control ears were correlated with the Student t test; chi(2) analysis was used to correlate pathologic findings of the TM and ME. RESULTS: Thicknesses in all quadrants except the umbo were increased in MOM because of infiltration of inflammatory cells and fibrosis. The most common ME pathologies were granulation tissue and fibrosis. Significant correlations included (1) TM retraction and ME granulation tissue and fibrosis and (2) pars flaccida, posterosuperior, and anteroinferior thickness and ME granulation tissue and fibrosis. CONCLUSION: TM changes are likely to occur in patients with otitis media with effusion (MOM), and their presence is a strong indication of underlying ME pathology.

Adolescent↗
PubMed2000

Development of the middle ear in neonatal chinchillas. I. Birth to 14 days.

Measures of middle-ear function in humans show large differences among neonates, infants, and adults. In contrast, hearing sensitivity is essentially mature at birth. Hypotheses that have been proposed to explain the developmental changes in middle-ear function include: (i) contaminating effects of the immature neonatal ear-canal wall and (ii) persistent fetal tissue in the ear canal, tympanic membrane (TM), and middle-ear space. To better understand the relationships between middle-ear function, hearing sensitivity and the structure of the middle ear, 30 chinchillas, aged 1-14 days, were studied. Middle-ear function was assessed by multifrequency tympanometry with probe tones ranging from 226 to 2,000 Hz. Hearing sensitivity was measured by auditory brainstem response using clicks and 1, 2, 4, and 8 kHz tone bursts. Structural characteristics were analyzed from temporal bone histologic preparations. At all frequencies, the acoustic admittance of the neonatal car is very low and tympanometric patterns are complex and irregular, compared to adult animals. The admittance is essentially constant from 1 to 14 days, indicating that developmental changes occur over a much wider age span than that investigated here. Hearing sensitivity of the chinchilla appears to be mature at birth. Histologic analysis indicated that there were no age-related changes in TM thickness, TM diameter, distance from TM to promontory, and stapes footplate diameter. There were small increases in bone thickness, middle-ear area, mastoid bulla area, and in the perimeters of the middle ear and mastoid bulla. There were no significant amounts of loose mesenchyme or other fetal tissue in the middle-ear space.

Acoustic Impedance Tests↗
PubMed2000

Identification of MUC5B mucin gene in human middle ear with chronic otitis media.

OBJECTIVES: To identify the mucin gene and its expressing cells in the middle ear mucosa with chronic otitis media (COM), and to study the correlation between infiltration of inflammatory cells in the submucosa and expression of the mucin gene in the mucosal epithelium with COM. STUDY DESIGN: Middle ear mucosal specimens removed from the inferior promontory area of 19 patients undergoing middle ear surgery for COM were studied. METHODS: Sections were stained with H&E, Alcian blue-periodic acid Schiff (AB-PAS), polyclonal MUC5B antibody, and specific MUC5B riboprobe for histological, histochemical, immunohistochemical, and mucin mRNA analyses. RESULTS: H&E staining revealed pseudostratified epithelia in 18 of the middle ear specimens with COM and cuboidal secretory epithelia in one. AB-PAS staining of epithelia revealed abundant secretory cells and their products (glycoconjugates). In situ hybridization and immunohistochemistry studies demonstrated that the secretory cells of the middle ear mucosa with COM expressed MUC5B mucin mRNA and its product MUC5B mucin. CONCLUSIONS: The MUC5B mucin gene and its product were identified in the middle ear secretory cells of patients with COM. Its expression was extensive in pseudostratified mucosal epithelia and related to infiltration of inflammatory cells in the submucosa of the middle ear cleft with COM, suggestive that inflammatory cell products are involved in the production of MUC5B.

Adolescent↗
PubMed1999

Tympanic membrane/middle ear pathologic correlates in chronic otitis media.

OBJECTIVE: To correlate pathologic findings of the tympanic membrane with pathologic changes in the middle ear cleft in chronic otitis media. STUDY DESIGN: Retrospective. MATERIAL AND METHODS: One hundred-fifty temporal bones from 97 subjects with chronic otitis media (defined as middle ear pathologic changes including granulation tissue, fluid, cholesteatoma, cholesterol granuloma, tympanosclerosis, and ossicular changes) were selected to correlate the presence of these middle ear pathologies with histopathologic changes of the tympanic membrane. The tympanic membrane pathologies included perforation, myringosclerosis, retraction, hemorrhage, fluid-filled cystic spaces, or dilated vessels. Temporal bones were also assessed for atelectasis. Fifty-six normal temporal bones were taken as controls for measurements. RESULTS: Significant correlations between tympanic membrane and middle ear pathology included myringosclerosis and granulation tissue, myringosclerosis and ossicular pathology, retraction and cholesterol granuloma, retraction and cholesteatoma, retraction and ossicular pathology, perforation and ossicular pathology, and hemorrhage and granulation tissue. Additive effects of some pathologies were also observed. Almost half the bones with middle ear pathology had no associated tympanic membrane pathology, whereas multiple pathologic changes in the tympanic membrane generally showed underlying multiple pathologic changes in the middle ear. CONCLUSION: When tympanic membrane pathology is detected otoscopically, its presence, alone or in combination, can be a strong indicator of underlying middle ear pathology. However, a normal-appearing tympanic membrane does not exclude the possibility of middle ear pathology. These findings suggest the need for other diagnostic tools such as multifrequency tympanometry and otoacoustic emissions to complement otoscopy for diagnosis of middle ear pathology, especially in a tympanic membrane that appears "normal."

Adolescent↗
PubMed1999

Study of systemic lupus erythematosus in temporal bones.

Despite some reports of sensorineural hearing loss with systemic lupus erythematosus (SLE), its pathologic correlate has remained unidentified due to the scarcity of human temporal bone studies. We here present findings in 14 temporal bones from 7 patients with SLE, examined histologically and immunohistochemically for pathologic conditions in the cochlea that might relate to their otologic histories. Blue-staining concretions were seen in the stria vascularis of 6 ears. Most of the cases showed a loss of spiral ganglion cells, with various degrees of hair cell loss and atrophy of the stria vascularis. One ear demonstrated formation of fibrous tissue and bone throughout the cochlea, with complete loss of the membranous labyrinth. Cochlear hydrops was found in only 1 ear. These findings in temporal bones from patients with SLE are discussed in relation to autoimmune disease of the inner ear.

Adolescent↗
PubMed1998

Clinical-histopathological correlations of pitfalls in middle ear surgery.

Significant anatomical variations within the middle ear are described as well as atypical histopathological findings in 13 selected human temporal bones. Bones studied included such vascular and bony abnormalities as carotid artery canal dehiscence, a high jugular bulb, persistent stapedial artery and facial nerve canal dehiscences. Bones also included obliterative otosclerosis, malleus head fixation and a variety of chronic inflammatory changes and/or sequelae. Those features considered to render cases prone to complications are detailed.

Ear, Middle↗
PubMed1998

Histopathology of human temporal bone after cis-platinum, radiation, or both.

Preserving organs by use of multiple modalities has become protocol in treating squamous cell carcinomas of the head and neck, but cis-platinum and radiation can impair hearing. To determine the effect of cis-platinum, radiation, or a combination of these treatments on the temporal bone, we studied histopathologic slides of 15 human temporal bones: four after cis-platinum, five after radiation, two after combined treatment, and four from normal controls. Hair cells and cells in spiral ganglia were counted in reconstructed organs of Corti. Lumen-to-diameter indexes in arterioles near facial nerves were quantified for four normal controls and seven irradiated patients. Available audiograms were compared. Decreased spiral ganglion cells, loss of inner and outer hair cells, and atrophy of stria vascularis were demonstrated in groups receiving cis-platinum, radiation, and combinations, compared with age-matched controls. Arterioles around facial nerves demonstrated fibrinous clots within the intima, endothelial proliferation, and hypertrophy and fibrosis of vascular walls in smooth muscle. Fibrosis in connective tissue was clearly progressive after radiation. Cis-platinum and radiation can contribute to otologic sequelae, including sensorineural hearing losses, vascular changes, serous effusion, or fibrosis. Prophylactic treatments and techniques to deliver them should be considered for protection of temporal bones and preservation of hearing after oncologic modalities.

Adult↗