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Biomedical subjects

C D Bluestone

Publications and source records attributed to C D Bluestone.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Eustachian tube function in cleft palate children.

The cleft palate population has a high prevalence of chronic otitis media with effusion (OME). The present study attempts to relate this pathology to a functional obstruction of the eustachian tube (ET). Employing two methods, the forced-response test and the inflation-deflation test, various parameters of ET function were evaluated in 41 children and adolescents with cleft palates. The results indicated that cleft palate children have a limited ability to open the ET actively by swallowing, as evidenced by an inability to equilibrate applied positive or negative pressures. These children demonstrated little ability to alter pressure in the middle ear (ME) by either the Valsalva or Toynbee maneuver. Passive ET airflow resistance in these children is not different from that of a traumatic perforation group. However, in the majority of cases (73%), the resistance of the tube increased with swallowing, suggesting a constriction of the ET rather than a dilation. Further, for those individuals capable of tubal dilation, the efficiency of dilation as measured by the resistance ratio was significantly less than that reported for the traumatic perforation group. Eustachian tube function in this population was not demonstrably dependent on age, sex, or type of cleft. The cleft palate children of the present study had severe functional obstruction of the ET. This obstruction was primarily related to the inability of the tensor veli palatini (TVP) muscle to dilate the ET actively during swallowing and appears to be the major factor responsible for the pathogenesis of OME in this population.

Adolescent↗
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Nonhuman primate model of cleft palate and its implications for middle ear pathology.

The present study is a preliminary report on the development of a nonhuman primate model of cleft palate and middle ear (ME) disease. The causal relationship between a surgical cleft of the soft palate only or a cleft of the hard and soft palate and otitis media with effusion (OME) was investigated in rhesus monkeys. Prior to clefting, ME status was documented by pneumatic otoscopy or otomicroscopic examination and tympanometry over a period of at least five months. A minimum of four preoperative eustachian tube (ET) function evaluations were performed employing the inflation-deflation and the forced-response tests. These procedures were repeated following surgery and during a long-term follow-up. Seventeen of the 18 ears developed a recurrent OME. Postoperative ME pressures were initially high negative values. After the first two postoperative months, high positive ME pressures were recorded. The forced-response test showed little to no long-term changes in passive and active tubal resistances or in the efficiency of tubal dilation as a result of surgery. The inflation-deflation test showed higher opening and closing pressures and a limited and more variable ability to equilibrate applied positive and negative ME pressures following surgery. Both ME status and ET function appeared to improve with time. These findings indicated that the pathogenesis of recurrent OME in this animal model may have been due to changes in ET function associated with an abnormal nasopharynx rather than aberrant tensor veli palatini (TVP) muscle function.

Animals↗
PubMedDate not supplied

Effect of surgical alterations of the tensor veli palatini muscle on eustachian tube function.

Previous studies in humans have indicated that functional obstruction of the eustachian tube (ET) is an important factor in the pathogenesis of otitis media with effusion (OME). This type of obstruction appears to be related to the structural properties of the tube, or to an inefficient active tubal opening mechanism, or both. In this study, functional ET obstruction was created in 22 rhesus monkeys (Macaca mulatta) by surgically altering the tensor veli palatini (TVP) muscle using three different procedures: 1) complete excision of the muscle; 2) transection of the superficial muscle bundle; or 3) transposition of the muscle tendon medial to the hamular process. Prior to surgery, weekly tympanometry, pneumatic otoscopy, and otomicroscpic examinations were performed for a period of at least six months to document middle ear (ME) status. A minimum of four ET function tests were performed on each animal using the inflation-deflation and forced-response tests. Following surgery, these tests and examinations were continued for periods of up to one year. Postoperatively, the animals in which the TVP had been excised developed a sterile ME effusion which proved to be a chronic condition which persisted throughout the follow-up period. Eustachian tube function tests showed a complete absence of any active tubal dilation by swallowing. Animals that had the muscle transected developed abnormal ME pressures , or effusions, or both, which returned to normal in some ears, but which were recurrent or chronic in others. Eustachian tube function tests in these animals showed an initial loss of active tubal function which gradually improved, but not to normal levels, presumably as a result of healing of the muscle. In cases in which the muscle was transposed the ME pathology and ET dysfunction were similar after the surgery, but improved within a short period of time. These data suggest that alteration of the TVP muscle can create functional obstruction of the ET. The severity of ET obstruction depends upon the surgical procedure undertaken. The results of postoperative ET function tests were similar to those recorded from children with recurrent and chronic OME.

Animals↗
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Gas absorption in the middle ear.

The middle ear (ME) pressure of alert and anesthetized rhesus monkeys was monitored by serial tympanograms in order to determine the gas absorption process in the ME cavity. During the four-hour observation period the ME pressure showed small, random fluctuations around zero pressure in the alert animals, whereas in the anesthetized animals, following an initial positive pressure phase, the ME pressure reached a plateau at an average pressure of -60 mm H2O. The ME gas composition was changed by air or oxygen gas politzerization in anesthetized animals to determine the effect of different initial gas compositions on the rate of absorption of the gas and on the magnitude of ME pressure. Politzerization with air and with oxygen gas resulted in average maximum ME pressures of -400 and -730 mm H2O, respectively. The experimental evidence suggested that the physiological composition of ME gases is nearly that of the surrounding environment and that the rate of gas absorption is low. When the gas composition of the ME is changed, the ME pressure decreases considerably. Based on these findings, a possible mechanism for the development of negative ME pressure is proposed.

Absorption↗
PubMedDate not supplied

Sonometric evaluation of eustachian tube function using broadband stimuli.

New measurements of acoustical transmission through the eustachian tube (ET) have been obtained in a series of experiments directed toward the development of a clinical instrument to assess ET function behind an intact tympanic membrane (TM). Using a sound conduction method, a sound source was placed in one nostril, and the acoustical energy that was transmitted through the ET was measured by a microphone placed in the ear canal. The present study used a broadband noise as the acoustical stimulus, in contrast to the tonal stimuli employed in previous investigations. This stimulus was chosen because it is believed to reduce the variability in the data due to intersubject differences in the acoustics of the nasopharynx and ET, and to avoid any a priori assumptions concerning the specific frequencies that would be of greatest diagnostic significance. Averaged spectra of the sound transmitted to the ear canal were obtained for three experimental conditions: acoustical source present during subject swallowing, source present with no swallowing, and subject swallowing with source absent. A Bayesian classification scheme based on the statistics of these spectra was used in classifying subjects into one of two possible categories, normal and abnormal ET function. A comparison was made between sonometric classification and classification based on a tympanometric ET function test. Correlation between the two methods was 87.1%.

Acoustic Impedance Tests↗
PubMedDate not supplied

Identification of otitis media with effusion in children.

In an effort to establish the diagnostic value of otoscopy, tympanometry, and the middle ear (ME) muscle reflex in the identification of otitis media with effusion (OME), the diagnostic findings by these three methods were compared with the findings at myringotomy in 333 children (500 ears). The study showed that even experienced clinicians had some difficulty in identifying those ears with effusion (sensitivity) and had even greater difficulty in making a diagnosis of those ears without an effusion (specificity). However, tympanometry, employing patterns that have been validated with myringotomy findings, was found to be more accurate. On the other hand, assessment of the ME muscle reflex as a diagnostic method was unacceptable due to an extremely low specificity (52%). An algorithm derived from the combination of the three methods had highest sensitivity (97%) and specificity (90%).

Acoustic Impedance Tests↗
PubMedDate not supplied

Effect of decongestant with or without antihistamine on eustachian tube function.

In an attempt to determine the effect of a decongestant with or without an antihistamine on the ventilatory function of the eustachian tube (ET), two separate studies were conducted in 50 children who had had chronic or recurrent otitis media with effusion (OME) and in whom tympanostomy tubes had been inserted previously. The first was a double-blind study that compared the effect of an oral decongestant, pseudoephedrine hydrochloride, with that of a placebo in 22 children who developed an upper respiratory infection (URI) during an observation period. Certain measures of ET function were significantly elevated above baseline values during the URI, which was attributed to intrinsic mechanical obstruction of the ET. It was found that the oral decongestants tended to alter these parameters of ET function in the direction of the baseline (preURI) values. Even though the effect was statistically significant, the favorable changes in measurements of tubal function were only partial and were more prominent on the second day of the trial after the subjects had received four doses of the decongestant. However, the administration of nasal spray of 1% ephedrine appeared to have no apparent effect on ET function in these children. The second study was a double-blind crossover design. In this study of 28 children who did not have a URI, the effect of a decongestant-antihistamine combination (pseudoephedrine hydrochloride and chlorpheniramine maleate) was compared with that of a placebo. When the subjects were given the decongestant-antihistamine medication, there were favorable changes in certain ET function measures which were not observed when they received the placebo. Again, the response differences between the two groups were statistically significant. Even though these two studies indicated that an oral decongestant appeared to affect favorably the ET function of children who had a URI, and that the combination of an oral decongestant and antihistamine had a similar effect on tubal function in children without a URI, an evaluation of the efficacy of these commonly employed medications must await the results of controlled clinical trials in children with OME.

Adolescent↗
PubMedDate not supplied

Efficacy of adenoidectomy in recurrent otitis media. Historical overview and preliminary results from a randomized, controlled trial.

Adenoidectomy is well established as a procedure for treating children with recurrent or persistent otitis media. Many physicians also believe that when adenoidectomy is undertaken for otitis media, tonsillectomy also should be done routinely. Thus otitis media serves as the justification for a substantial proportion of the tonsil and adenoid operations carried out on children. Nonetheless, evidence supporting the efficacy of adenoidectomy, or tonsillectomy and adenoidectomy (T&A), for otitis media is scant and inconclusive. Only six prospective studies have been reported, and in all but two of them, the combination of adenoidectomy with tonsillectomy, rather than adenoidectomy alone, was tested. The results were contradictory, perhaps because of all the studies contained flaws in design or methodology or both. Whether adenoidectomy or T&A are efficacious remains entirely uncertain. We are attempting to address the question currently in a prospective study in which children considered at high risk for otitis media are entered into a randomized, controlled clinical trial of adenoidectomy. The trial is complicated by the need to take adequate account of subject variables such as age, sex, adenoid size, and the presence or absence of allergy, and of the important treatment variables of concomitant myringotomy with tympanostomy tube insertion. Outcome measurements employed in the trial include the number of episodes per year of acute otitis media, the persistence of middle ear effusion, and the frequency of subsequent myringotomy. Data thus far collected in the study are not sufficient to reach a conclusion for or against the efficacy of adenoidectomy for otitis media, but it is apparent that adenoidectomy by no means eliminates the problem.

Adenoidectomy↗
PubMedDate not supplied

Lysosomal hydrolases in middle ear effusions.

Biochemical studies of middle ear effusions have demonstrated generally higher levels of certain hydrolytic and oxidative enzymes in mucoid fluids when compared to serous. We have extended these studies by analyzing middle ear effusions for the content of a large number of lysosomal hydrolases. The mean specific activity for alpha-glucosidase in mucoid fluids was found to be ten times that for serous fluids while alpha-mannosidase, beta-glucuronidase, hexosaminidase, acid phosphatase, beta-galactosidase, alkaline phosphatase, and lactate dehydrogenase were found to be three to five times greater in mucoid than serous effusions. In this study the specific enzyme activities for lysosomal hydrolases from purulent effusions were found to be intermediate between the activities in serous and mucoid effusions. No significant correlation was found between the specific activities of lysosomal hydrolases and the presence or absence of bacteria in mucoid or serous middle ear effusions. The hexosaminidase isozyme distribution was found to be identical for serous and mucoid fluids and similar to that found in human serum. However, the isozyme pattern of beta-glucuronidase in mucoid effusions was significantly different than that in normal human serum as mucoid fluids contain a large amount of an anionic isoenzyme of beta-glucuronidase that is barely detectable in human serum.

Adolescent↗
PubMedDate not supplied

Pharmacokinetics of cefaclor in chronic middle ear effusions.

Fifty children aged 1 to 13 years with chronic or recurrent otitis media with effusion received a single dose of cefaclor (15 mg/kg body weight) by the oral route 30 minutes to seven hours before the removal of middle ear effusion and insertion of tympanostomy tubes. Serum and middle ear aspirate concentrations of the antibiotic were determined employing a microbiological assay technique by a disk diffusion method. Middle ear specimens were also cultured for aerobic bacteria. The mean peak serum concentration level (8.49 +/- 7.89 micrograms/ml) was observed after 30 minutes, whereas the middle ear peak level (0.47 +/- 0.78 micrograms/ml) occurred after one hour. Of the 87 middle ear specimens, 37 had cefaclor concentrations which were detectable within the resolution of the bioassay method (greater than 0.16 micrograms/ml). There was no correlation between the type of middle ear effusion (mucoid or serous) and the concentration of cefaclor in the middle ear. Only 18% of the middle ear cultures were positive for aerobic bacteria; Hemophilus influenzae was the most common organism.

Adolescent↗
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Comparison of cefaclor and amoxicillin for acute otitis media with effusion.

A double-blind randomized clinical trial was conducted comparing cefaclor and amoxicillin for the treatment of acute otitis media with effusion in 110 children (150 ears). Each child underwent unilateral or bilateral tympanocentesis and then randomly received a 14-day course of either amoxicillin or cefaclor. Of 57 children in the cefaclor group, only 3 children (5.3%) had persistent or recurrent symptoms during the 14-day course of treatment, as compared to 5 of 53 children (9.4%) in the amoxicillin group, but this difference is not significant. After completion of the 14 days of therapy, 45 of 76 ears (59.2%) of the children in the cefaclor group were effusion-free, as compared to only 28 of 64 ears (43.7%) of the children in the amoxicillin group. When adjusted for age and race, this difference is statistically significant (p = .03). However, the difference between the effect of the two antimicrobials is not statistically significant in children. Cefaclor is a reasonable choice for antimicrobial therapy for acute otitis media with effusion, and from these study findings, it appears that cefaclor may be more effective than amoxicillin in resolving the middle ear effusion at the completion of 14-day therapy.

Acute Disease↗
PubMedDate not supplied

Comparison of normal eustachian tube function in the rhesus monkey and man.

Employing inflation-deflation and forced-response tests, the eustachian tube (ET) function was evaluated in six adult human subjects with traumatic perforation of the tympanic membrane and otherwise negative otologic histories; and 15 juvenile or adult rhesus monkeys with freshly created myringotomy perforations of the tympanic membrane and otherwise documented normal middle ears. The study findings demonstrated that the rhesus monkey ET functions as a scaled down model of the ET of man, exhibiting a shorter tubal dilation duration and a lesser capacity to pass air. When ET function in the two species was compared using a dimensionless measure expressing the tubal dilation efficiency, the operational biomechanics of both systems were found to be almost identical. These observed functional homologies between man and the rhesus monkey ET systems suggest that the rhesus monkey is a suitable animal model in which to study the pathogenesis of otitis media with effusion, stemming from ET dysfunction.

Adult↗
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Liver transplants in children: importance for the otolaryngologist.

Orthotopic liver transplantation (OTLT) for children with end stage liver failure has doubled 1-year survival rates to over 70% with the employment of cyclosporine and prednisone in conjunction with skilled surgical and medical specialists providing supportive care. The otolaryngology service has assisted in the care of 18 of 61 children undergoing OTLT, particularly in managing respiratory problems that required improved pulmonary toilet and prolonged intubation. The prevention of atelectasis of the lung and subsequent sepsis appears to be improved by prompt bronchoscopy.

Adolescent↗
PubMedDate not supplied

Effect of certain head and neck tumors and their management on the ventilatory function of the eustachian tube.

A prospective study was carried out which tested three hypotheses: 1) certain tumors of the head and neck that originate in sites other than the nasopharynx may cause middle ear effusion; 2) middle ear effusion is a predictable sequela of radical maxillectomy as well as total or partial resection of the soft palate; and 3) middle ear effusions that follow surgery to remove head and neck lesions are due to disturbances in palatal function, specifically to tensor veli palatini muscle dysfunction. Our results indicate that one fourth of all subjects had some evidence of middle ear abnormality prior to entering into treatment although they were asymptomatic. The treatment process influenced the function of the middle ear, as 79% of the subjects experienced middle ear-eustachian tube dysfunction following treatment, and 23% were found to have developed a perforation of the tympanic membrane or required myringotomy and tube insertion to relieve middle ear effusion. The results of these studies indicate that surgery that is adequate to remove cancer of the maxilla, tonsil, or palate in most cases interferes with the function of the tensor veli palatini muscle, resulting in functional eustachian tube obstruction. The need for attention to and the treatment of middle ear effusion in such patients is emphasized in light of other sensory deficits in this patient population.

Adult↗
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Lymphoma invading the anterior eustachian tube. Temporal bone histopathology of functional tubal obstruction.

The temporal bones of a man with poorly differentiated lymphocytic lymphoma, who had had a bilateral conductive hearing loss and incomplete left-sided facial palsy, were obtained. Sections were prepared for histologic study by staining with hematoxylin and eosin and were examined under the light microscope. The left temporal bone showed marked tumor cell involvement, not only of the lateral part of the cartilaginous portion of the eustachian tube (ET) where the tensor veli palatini muscle had been partially destroyed, but also in the anterior part of the temporal bone. A serous middle ear effusion was present, but the lumen of the ET was unaffected by tumor or inflammation. The pathological findings in the right temporal bone were similar to those in the left, although the cartilaginous part of the ET and its surrounding structures were not available for study. The pathogenesis of otitis media with effusion appeared to be secondary to functional ET obstruction, due to the dysfunction of the tensor veli palatini muscle as a result of the tumor destruction. This case is the first to be reported in which functional ET obstruction, secondary to tumor invasion of the active muscle dilator of the ET, has been histologically confirmed.

Adult↗
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Synchronous airway lesions in infancy.

Stridor in the young infant is evaluated by careful laryngoscopy. When a lesion of the larynx is diagnosed, the necessity and risk of bronchoscopy are challenged. To assess the need for careful examination of both the upper and lower respiratory tract, a 2-year retrospective study was performed at the Children's Hospital of Pittsburgh. Of 103 infants who underwent diagnostic laryngoscopy and bronchoscopy for airway obstruction, stridor, or both, 18 (17.5%) had two or more synchronous airway lesions detected. Laryngoscopy alone, without further workup of the entire respiratory tract (ie, bronchoscopy, radiographic studies) may fail to detect concurrent disorders in infants with airway obstruction.

Airway Obstruction↗
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An animal model of acute otitis media consequent to beta-lactamase-producing nontypable Haemophilus influenzae.

A chinchilla model of acute otitis media with effusion consequent to beta-lactamase-producing nontypable Haemophilus influenzae was developed using the method of direct inoculation of 145 colony-forming units (CFU) or 252 CFU of beta-lactamase-producing nontypable H influenzae into the right superior bullae of 40 chinchillas. The course of the disease was documented longitudinally by otomicroscopy, tympanometry, and periodic culturing of the middle ears. Onset of the disease occurred in 100% of the animals between two and six days postinoculation and resolution was complete in all ears by day 36. Results of rechallenge with the same organism support the combined effect of a local and weaker systemic middle ear protective mechanism rendering resistance to reinfection with a homologous organism in the chinchilla.

Acute Disease↗