Mutations in a novel cochlear gene cause DFNA9, a human nonsyndromic deafness with vestibular dysfunction.

DFNA9 is an autosomal dominant, nonsyndromic, progressive sensorineural hearing loss with vestibular pathology. Here we report three missense mutations in human COCH (previously described as Coch5b2), a novel cochlear gene, in three unrelated kindreds with DFNA9. All three residues mutated in DFNA9 are conserved in mouse and chicken Coch, and are found in a region containing four conserved cysteines with homology to a domain in factor C, a lipopolysaccharide-binding coagulation factor in Limulus polyphemus. COCH message, found at high levels in human cochlear and vestibular organs, occurs in the chicken inner ear in the regions of the auditory and vestibular nerve fibres, the neural and abneural limbs adjacent to the cochlear sensory epithelium and the stroma of the crista ampullaris of the vestibular labyrinth. These areas correspond to human inner ear structures which show histopathological findings of acidophilic ground substance in DFNA9 patients.

Tissue engineered cartilage: utilization of autologous serum and serum-free media for chondrocyte culture.

BACKGROUND: Standard culture medium contains bovine serum. If standard culture methodology is used for future human tissue-engineering, unknown risks of infection from bovine disease or immune reaction to foreign proteins theoretically might occur. In this study we wished to evaluate the potential of chondrocyte expansion using autologous and serum free media. METHODS: Autologous auricular cartilage was harvested in a swine model. An initial concentration of 100x10(3) cells per group were expanded in three groups. Group A, F-12 with 10% fetal calf serum; Group B, F-12 supplemented with 10% autologous serum; Group C, F-12 supplemented with growth factors. Cell numbers were counted at days 3, 6, 9 and 12. RESULTS: The cells in all the three groups exhibited normal chondrocyte morphology. At early time points there was a statistically significant difference in the number of cells between Group A and the two other groups (p<0.05). By day 12, both Groups A and C demonstrated greater cell number as compared to Group B (p<0.05). CONCLUSION: The results suggest that both autologous serum as well as serum free media might be substituted for the expansion of the number of chondrocytes, thus avoiding the potential need for a bovine serum supplement.

Familial vocal cord dysfunction.

Vocal cord paralysis is a common cause of neonatal stridor. Familial vocal cord dysfunction, however, is unusual. All three siblings in one family had neonatal stridor. Vocal cord dysfunction was confirmed after endoscopic examination in two of the children; a temporary tracheotomy was required by one child. Results of evaluation, including pulmonary function tests, suggest discrete dysfunction localized to the neuromuscular pathway responsible for vocal cord abduction. Endoscopy is of prime importance in the diagnosis of vocal cord dysfunction. In considering therapy, the physician must weigh both the potentially life-threatening nature of vocal cord paralysis, as well as the likelihood of eventual spontaneous resolution of many familial and idiopathic cases.

A new device for diagnosis and treatment of neonatal pneumothorax.

A new closed-system device for the diagnosis and treatment of pneumothorax was evaluated in ten New Zealand white rabbits and compared with and open-system needle. The closed-system device proved to be safe for diagnostic thoracentesis. There were no pneumothoraces as a result of the procedure with the closed-system device as confirmed by chest roentgenograms and pleural pressure measurements. In contrast, 70% of the diagnostic thoracenteses with the open-system needle were associated with pneumothorax documented by x-ray films and a significant increase in mean pleural pressure. The new apparatus was more efficacious for evacuation of pneumothoraces because complete air removal occurred in 90% of the rabbits as compared with 60% of trials with the open-system needle. If the efficacy of the new closed-system device proves to be good in human infants, the pediatrician encountering a tension pneumothorax in the newborn can use a completely assembled system that is safe for diagnosing and treating this acute life-threatening condition.

Production of male pseudohermaphroditism in rats by two new inhibitors of steroid 17alpha-hydroxylase and C 17-20 lyase.

Two new synthetic steroid analogues, (I) 16beta-bromo-3beta,17alpha-dihydroxy-5alpha-pregnane-11,20-dione and (II) 17beta-ureido-1,4-androstadien-3-one have been shown to give kinetic patterns consistent with active-site-directed irreversible inhibition of adult rat testicular microsomal steroid 17alpha-hydroxylase and C17-20 lyase in vitro. Administration of both analogues to adult male rats for 24 h produced potent inhibition of these testicular enzymes in vivo. Given to pregnant rats during the critical period of male organogenesis they produced hypospadias: a characteristic of the syndrome in man in which these enzymes are defective genetically. Given to male rat pups during the first 9 days of life, inhibitor II produced significantly smaller prostates and seminal vesicles in adulthood, indicating the usefulness of this inhibitor in studies on the role of testosterone in neonatal programming of target organ size in adulthood. Thus, two new enzyme inhibitors have been shown to block testosterone production in the foetal and neonatal rat selectively at the site of the hydroxylase without other apparent hormonal effects or influence on adrenal size.

Expansion of the number of human auricular chondrocytes: recycling of culture media containing floating cells.

To grow a complete human size auricle by utilizing the principles of tissue engineering, a large number of chondrocytes is required for initial implantation. The number of chondrocytes can be increased by repeated passaging or by incubation with different growth factors, both of which can promote dedifferentiation. New methods of chondrocyte expansion over a relatively brief time period for potential practical application are required. In this study auricular chondrocytes were obtained from patients and cultured in vitro. Two groups of cells were created. Group A chondrocyte number was increased by repeated passaging. Group B cells were grown from floating culture medium and their number was increased both by passaging and by repeated recycling of the culture medium. Chondrocytes from both groups were implanted in nude mice for 8 weeks to generate tissue-engineered cartilage. Flow cytometry studies performed on both groups confirmed the presence of two distinct populations of structures as the source of chondrocytes from the recycled medium. Repeated recycling of the culture medium demonstrates a promising method to increase the number of chondrocytes in vitro for clinical application.

The effect of fibroblast growth factor and transforming growth factor-beta on porcine chondrocytes and tissue-engineered autologous elastic cartilage.

Elastic cartilage responds mitogenically in vitro to transforming growth factor-beta (TGF-beta) and basic fibroblast growth factor (basic FGF). We studied the effects of these growth factors separately or in a combination on porcine auricular chondrocytes in vitro and on the autologous elastic cartilage produced. Cells were harvested from the elastic auricular cartilage of 16- to 18-kg Yorkshire swine. Viability and quantification of the cells was determined. Cells were plated at equal concentration and studied in vitro in one of four identical media environments except for the growth factors: Group I contained Ham's F-12 with supplements but no growth factors, Group II also contained basic-FGF, Group III also contained TGF-beta, and Group IV also contained a combination of both growth factors. After 3 weeks in vitro, the cells were chemically dissociated with 0.25% trypsin. Cell suspensions composed of 3 x 10(7) cells/cc in 30% Pluronic F-127/Ham's F-12 were injected subcutaneously. Implants were harvested at 6, 8, 10, and 12 weeks of in vivo culture and then were examined with histologic stains. After 3 weeks of in vitro culture the total number of cells was as follows: Group I, 1.8 x 10(8); Group II, 3.5 x 10(8); Group III, 1.3 x 10(8); Group IV, 2.5 x 10(8). After 8 weeks of in vivo autologous implantation, the average weight (g) and volume (cm3) of each group was as follows: Group I, 0.7 g/0.15 cm3; Group II, 1.5 g/0.8 cm3; Group III, 0.6 g/0.1 cm3; Group IV, 1.2 g/0.3 cm3. Histologically, Groups I, II, and IV generated cartilage similar to native elastic cartilage, but Group III specimens demonstrated fibrous tissue ingrowth. Basic FGF produced the most positive enhancement on the quantity and quality of autologous tissue engineered elastic cartilage produced in this porcine model both in vitro and in vivo.

Tissue-engineered human auricular cartilage demonstrates euploidy by flow cytometry.

Transforming growth factor-beta (TGF-beta) and basic fibroblast growth factor (bFGF) are known to stimulate the rate of chondrocyte proliferation. The theoretical risk of malignant transformation associated with growth factor stimulation of chondrocytes should be addressed; aneuploidy has been found to occur in human cartilaginous tumors. In this study, chondrocytes were obtained from six human auricles and cultured in vitro for 6 weeks in the presence or absence of TGF-beta and bFGF. Cells were analyzed for DNA at 3-, 4-, 5-, and 6-week intervals by flow cytometry (FACScan), which demonstrated no evidence of aneuploidy. A persistent increase in S-phase was noted in cells cultured only with TGF-beta. Cells were implanted in athymic mice, and after 8 weeks of implantation, the cartilage constructs formed were examined histologically. The tissue-engineered cartilage cultured originally in bFGF most resembled normal, native cartilage. Specimens cultured in TGF-beta produced suboptimal cartilage morphology. Flow cytometry shows no evidence of aneuploidy, with chondrocytes maintaining their normal diploid state. Further studies incorporating additional methods of analysis need to be done.

Inverted papilloma of the nose and paranasal sinuses in childhood and adolescence.

Inverted papilloma of the nose and paranasal sinuses is a tumor not usually associated with childhood. These five cases from the Massachusetts Eye and Ear Infirmary provide the only series in the literature. The patients ranged in age from 6 to 20 years. One case involved the septum exclusively; the patient experienced a recurrence. The other four cases were of sinus origin. One of these patients also experienced recurrences before definitive surgery. Another presented with a simultaneous squamous cell carcinoma. Evaluation of these cases demonstrates that the same successful, comprehensive surgical management advised for adults is justifiable in this younger age group.

Airway interruption in encephalopathic children: a clinical and histological analysis.

Severe, incessant aspiration can be a most troublesome sequel to the already tragic problem of a vegetative mental state in a previously normal child. Three patients, aged 2 to 4 years, underwent surgery to treat their aspiration. A different type of procedure was used for each patient: cord closure combined with an epiglottic flap, cord closure alone, and a laryngeal stent. Laryngeal histopathology of a case is presented for the first time; findings suggest that the theoretical reversibility of that particular type of procedure could prove formidable. Clinically, the immediate cessation of aspiration has provided all parents and health care personnel with a surprising sense of gratification and has enabled each child to be transferred to a less-costly care facility or to home.

Abnormalities of the neonatal ear: otoscopic observations, histologic observations, and a model for contamination of the middle ear by cellular contents of amniotic fluid.

It is unknown whether childhood ear disease could be present long before symptoms provoke an initial otoscopic examination. A newborn middle ear might or might not start in a pristine, privileged state. The clinician evaluating later infant and childhood ear disease is often unaware of the status of a patient's ear from the neonatal period, the earliest time at which the tympanic membrane can be evaluated. Adding to the physician's handicap, normative otoscopic and histologic data on the neonatal ear are incomplete. In order to test the hypothesis that disease in the neonatal middle ear may be more common than is generally appreciated, the population of critically ill neonates was selected for study since this group can provide both clinical as well as histologic data. This manuscript is divided into three parts. Clinically, otoscopic observations were analyzed on infants in an intensive care unit. Histologically, neonatal temporal bones were studied for normal anatomy and pathology of the middle ear and antrum. Experimentally, an animal study was performed to evaluate the potential effect of amniotic fluid cellular contents aspirated into the middle ear. I. Clinical Otoscopic Observations. Daily otoscopic examination was conducted on 44 neonates in an intensive care unit. Specific parameters of the otoscopic examination were evaluated to compare with the normal, translucent tympanic membrane of the older child. The otoscopic appearance was found to be abnormal in 97.7% of neonatal ears. Of the otoscopic parameters evaluated, right ears averaged 2.6 abnormalities and left ears averaged 2.5 otoscopic abnormalities. The otoscopic appearance of the neonate in the neonatal intensive care unit is nearly universally abnormal. II. Temporal Bone Histologic Observations. One hundred eleven temporal bones from 56 neonates were collected for histologic study by light microscopy. Mesenchyme filling more than 60% of the middle ear space was found in 13 bones. Amniotic fluid cellular content was detected in 90 bones. Purulent otitis media was detected in 24 bones. Varying amounts of blood were found in the middle ear space of 34 bones. Only 7 of the bones had no significant middle ear abnormality. It is concluded that in the critically ill neonate, the middle ear and antrum usually contain cellular or fluid material, often in significant volume, that would not be considered normal in the older patient. III. An Animal Model Simulating Contamination of the Middle Ear by Cellular Contents of Amniotic Fluid.(ABSTRACT TRUNCATED AT 400 WORDS)

Inlay tympanoplasty: cartilage butterfly technique.

For closure of a nonmarginal tympanic membrane perforation, currently popular techniques utilize either an underlay or an onlay approach. However, both procedures require incising canal skin. A transcanal inlay procedure could provide theoretical advantages of ease, speed, and comfort. Specifically designed cartilage that could facilitate the transcanal approach similar to placement of a solid tube was employed and evaluated. A transcanal cartilage butterfly inlay technique was found to be efficient and effective to close a subgroup of small-to-medium-sized tympanic membrane perforations including cases in which the condition of the tympanic membrane was somewhat hostile. Postoperative patient comfort was an additional benefit.

Embryonic middle ear mesenchyme disappears by redistribution.

OBJECTIVE: The fate of embryonic middle ear mesenchyme from a postgestational infant ear has been speculative. Recently a volume analysis of human neonatal temporal bones demonstrated that embryonic mesenchyme disappeared by redistribution and thinning to surface a growing middle ear space. If this model is accurate, interaction with amniotic fluid and the gestational environment should not influence mesenchymal behavior. Therefore an opossum marsupial model was compared with human data. METHODS: The temporal bones of opossum pups (20 to 36 days of age) were sectioned for histologic analysis. Computations were made for the volume of the middle ear air cavity (VAC), volume of the bone cavity (VBC), volume of mesenchyme (VM), and percentage of the middle ear occupied by mesenchyme (%M), which were plotted against height using regression statistics. These data were compared with human neonatal (0 to 30 days of age) temporal bones. RESULTS: In both the opossum and the human the VAC and the VBC increased in parallel with growth of the body. In the opossum the VAC and VBC both grew at 0.148 mm3/mm of body length. In humans, both the VAC and VBC grew 6.1 mm3/cm of body length. The VM in the opossum remained constant at 0.98 mm3, regardless of body length. In humans the VM remained constant at 71.7 mm3, regardless of body length. Therefore the %M proportionately decreased inversely with increasing ear size in both the opossum and the human neonate. CONCLUSION: This study supports a simple and credible explanation for the illusion of mesenchymal disappearance in the neonatal middle ear. The mesenchymal connective tissue redistributes to cover a larger surface area in a persistently enlarging cavity. These findings occur in different species, whether gestation is completed in an intrauterine or an extrauterine environment.

Neonatal mesenchyme temporal bone study: typical receding pattern versus increase in Potter's sequence.

The fate of mesenchyme, which lines the fetal and newborn bony middle ear, is not well understood. The authors wished to test previous observations that a greater amount of mesenchyme was found in Potter's sequence (renal anomalies, pulmonary hypoplasia, and oligohydramnios). Using celloidin-embedded neonatal temporal bones (68 cases, 123 ears), with clinical and autopsy information, middle ear volumes were compared among diagnostic groups using analysis of variance. In 16 ears of Potter's sequence cases the volume of mesenchyme increased in proportion to the size of the middle ear. Conversely, in all other cases the volume of mesenchyme remained constant compared to increasing middle ear size. Both the volume of the bony middle ear and the volume of the air cavity increased at 15 mm3/500 g of body weight (gbw). Mesenchyme percentage decreased by 2%/500 gbw. Middle ear mesenchyme appears to recede rather than reabsorb. However, in Potter's sequence cases the volume of mesenchyme increases, raising issues of a missing renal signal that inhibits mesenchymal growth under normal circumstances.

An assessment of grafts in the posterior cricoid lamina.

Subglottic stenosis is a recognized complication of prolonged intubation. To date, there is no uniformly successful operative procedure for severe subglottic stenosis, fulfilling the criteria of decannulation and a serviceable voice. The surgical ideals for such a procedure should include the use of autogenous grafting material, avoidance of internal stenting, and limited manipulation of the mucosa. This study was intended to assess the fate of isolated hyoid and thyroid alar grafts interposed in the posterior cricoid lamina. Additionally, anterior/posterior splits with and without anterior grafting were evaluated. Seventeen dogs were used in the determinate animal model. Vocal cord mobility was evaluated by direct laryngoscopy prior to sacrifice. Graphic gross anatomical specimens depict the effects of anterior/posterior splitting on the cricoid cartilage. Clinical correlations are suggested.

Management of nasal septal abscess.

Nasal septal abscesses are uncommon. Sixteen cases from the Massachusetts Eye and Ear Infirmary were reviewed retrospectively and are presented. The diagnosis, bacteriology, and pathophysiology are discussed. Immediate therapy is indicated to avoid cosmetic deformity or intracranial infection. Treatment is based on diagnostic needle aspiration, antibiotic coverage and surgical drainage.

Tympanostomy tubes: experience with removal.

Whereas the clinical indications for tympanostomy tube placement are well-established, the indications for operative tympanostomy tube removal remain unspecified. A 1-year retrospective review done at the Massachusetts Eye and Ear Infirmary revealed 131 tympanostomy tubes to have been removed under general anesthesia. Chronic otorrhea, granuloma formation, tube nonfunction due to blockage, and migration of the tube into the middle ear constituted the surgical indications in 75 cases. The remaining 56 tubes were removed on the physicians' judgment that artificial ventilation was no longer required. Selected cases are presented. While the vast majority of tubes spontaneously extrude uneventfully, a comparatively small number of patients do require operative tube removal. Practice guidelines for surgical tube removal are suggested.

Tissue engineering of a human sized and shaped auricle using a mold.

OBJECTIVES: The creation of a tissue-engineered auricle was initially successful in an immunocompromised nude mouse model. Subsequently, an immunocompetent porcine model successfully generated a helical construct. We wished to evaluate the novel technique of using a mold to create a complete, anatomically refined auricle in a large animal model. METHODS: Mixtures of autogenous chondrocytes and biodegradable polymers were used inside a perforated, auricle shaped hollow gold mold. Three biodegradable polymers (calcium alginate, pluronic F-127, and polyglycolic acid) were used to retain the seeded chondrocytes inside the mold. These molds, along with a control, were implanted subcutaneously in the abdominal area of 10 animals (pigs and sheep). The constructs were removed after 8 to 20 weeks and were assessed by gross morphology and histology. RESULTS: All the gold implants were well tolerated by the animals. The implants using calcium alginate (n = 3) generated constructs of the exact shape and size of a normal human ear; the histology demonstrated mostly normal cartilage with some persistent alginate. The implants with pluronic F-127 (n = 3) resulted in cartilage with essentially normal histology, although leakage outside the molds and external cartilage generation was noted. Polyglycolic acid implants (n = 3) produced no useful cartilage because of an inflammatory reaction with fibrosis. The empty control mold (n = 1) demonstrated only a very small amount of fibrous tissue inside. CONCLUSION: A tissue-engineered human sized auricle of normal anatomic definition can be generated in an immunocompetent large-animal model using a mold technique. Although further refinements will be necessary, the technique appears promising for potential use in patients with microtia.

Engineering autogenous cartilage in the shape of a helix using an injectable hydrogel scaffold.

OBJECTIVE: Previous successful efforts to tissue engineer cartilage for an auricle have used an immunocompromised nude mouse xenograft model. Subsequent efforts in an immunocompetent autogenous animal model have been less successful because of an inflammatory response directed against the foreign scaffold polymer used to provide an auricular shape. We studied an alternative polymer material and surgical technique to engineer autogenous cartilage in the shape of a human ear helix using injectable hydrogel scaffolding, Pluronic F-127 (polyethylene oxide and polypropylene oxide). SUBJECT: Yorkshire swine. MATERIAL AND METHODS: Fresh autogenous chondrocytes were suspended in a biodegradable, biocompatible co-polymer hydrogel, Pluronic F-127, at a concentration of 3 x 10(7) cells/mL. To support the contour of the implant, a skin fold channel in the shape of the helix of a human ear was created in the skin in three sites on the ventral surface of the animal. The cell-hydrogel suspension was injected through the skin fold channel. For controls, injections were made into identical channels using either cells alone or the Pluronic F-127 without cells. After 10 weeks, the specimens were excised and examined both grossly and histologically. RESULTS: Grossly, all implants retained a helical-like shape. Excised specimens possessed flexible characteristics consistent with elastic cartilage. The specimens could be folded and twisted and on release of mechanical pressure would instantly return to the original shape. Histological evaluation of the implants using H&E, Safranin O, trichrome blue, and Verhoeff's stains demonstrated findings consistent with mature elastic cartilage. Control injection of hydrogel alone demonstrated no evidence of cartilage formation and control injection of chondrocytes alone showed evidence only of disassociated elastic cartilage. CONCLUSION: Injection of autologous porcine auricular chondrocytes suspended in a biodegradable, biocompatible hydrogel of Pluronic F-127 resulted in the formation of cartilage tissue in the approximate size and shape of a human ear helix. This preliminary method extends the concept of auricular tissue engineering from an immunocompromised xenograft animal model to an immunocompetent autologous animal model.

Microtia and significant auricular malformation. Ninety-two pediatric patients.

OBJECTIVE: To study congenital auricular malformation, an uncommon but serious condition. The literature about auricular malformation separates the medical, otologic, and auricular reconstructive elements; this study addresses all elements in a single report. DESIGN: A retrospective chart analysis of patients with microtia and severe auricular malformation from initial presentation through surgical reconstruction for those of appropriate age. SETTING: A single author's experience in a practice at a referral institution. PATIENTS: Ninety-two patients (108 ears). RESULTS: Early presentation at less than 1 year of age was noted for 40 patients. Coexisting medical conditions were noted in 16 patients. Seven patients demonstrated facial paralysis. Unexpected sensorineural hearing loss was discovered in six patients. Twenty-four patients had undergone auricular reconstruction at the time of this report. Additional patients had undergone skin tag removal, ventilation tube placement, and atresia repair. CONCLUSIONS: Children with microtia and significant auricular malformation require global attention to early family guidance, to expected and unexpected hearing loss, to language development, to associated medical conditions, and to both auricular and otologic reconstruction issues.