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1.
Ear Nose Throat J ; : 1455613241254643, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38752551

RESUMO

Preauricular sinuses are relatively common congenital anomalies of the soft tissues of the ear. By strict definition, when they connect 2 separate spaces, they are referred to as a preauricular fistula. This clinical entity was first described by Heusinger in 1864. Most preauricular sinuses have a small opening located anterior to the root of the helix. In rare cases, they are found posterior to the tragus, near the crus of the helix, and the ear lobule. The latter is the variant type preauricular sinus, also referred to as the "postauricular sinus," as the sinus tract opens posterior to the auricle. Recurrent infections or persistent discharge may require surgical excision which is ideally performed at a time when there is no inflammation. There are a variety of techniques for excision. Regardless of the surgical approach taken, it is of critical importance to remove the subcutaneous sac completely. We present a very rare case involving the co-occurrence of a preauricular sinus and postauricular sinus in a 33-year-old woman. We report this case with a review of the literature.

2.
J Audiol Otol ; 28(2): 79-87, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38695052

RESUMO

Cochlear implants (CIs) have demonstrated a clear functional benefit in children with severe-to-profound sensorineural hearing loss (SNHL) and thus have gained wide acceptance for treating deafness in the pediatric population. When evaluating young children for cochlear implantation, there are unique considerations beyond the standard issues addressed during surgery in adults. Because of advances in genetic testing, imaging resolution, CI technology, post-implant rehabilitation, and other factors, issues related to CI surgery in children continue to evolve. Such factors have led to changes in candidacy guidelines, vaccine requirements, and lowering of age requirement for surgery. In addition, differences in the anatomy and physiology of infants require special attention to ensure safety when operating on young children. This review summarizes these issues and provides guidance for surgeons treating children with SNHL.

3.
Laryngoscope ; 133(1): 73-78, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35470868

RESUMO

OBJECTIVES: (1) Identify the time required for completion, submission, and acceptance of a Triological Thesis and trends for thesis acceptance. (2) Determine the current Triological Society demographics and identify variances based on separated age groups of the current membership. STUDY DESIGN: Retrospective review of The Triological Society database and survey of candidates and fellows. METHODS: Data from the records of all candidates and fellows of the Triological Society were reviewed to determine the number of years from candidate to active fellow status for all members inducted into the Triological Society from 1990 to 2018. In addition, all current candidates, active and senior fellows were surveyed online to capture demographic data and opinions regarding the Triological Society. RESULTS: Since 1990, there has been a steady increase in the number of candidates and theses accepted. Of candidates successfully completing theses, 73% did so within 3 years and 90% within 5 years. Based on the 514 of 809 (64%) active and senior fellows responding to the survey, 83% reported being male and 15% female. Also, 73% reported as Caucasian, 12% Asian, 2% Hispanic, 2% Black, 0% Native American, and 2% Mixed Race. Of the 93 of 178 (52%) active candidates (those authorized to prepare a thesis) responding to the survey, 70% reported as male, 28% female, 58% Caucasian, 17% Asian, 6% Hispanic, 5% Black, 0% Native American, and 3% Mixed Race. CONCLUSIONS: The Triological Society continues to grow, and its membership is becoming more diverse, including more women and wider ethnic diversity. Candidates should plan for submitting their thesis as early as possible as data demonstrates the greatest likelihood of success if done within 3 years. LEVEL OF EVIDENCE: NA Laryngoscope, 133:73-78, 2023.


Assuntos
Hispânico ou Latino , População Branca , Feminino , Masculino , Humanos , Sociedades Médicas , Asiático , Estudos Retrospectivos
4.
Otolaryngol Clin North Am ; 55(6): 1139-1149, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36371131

RESUMO

The purpose of this article is to outline the current state of evaluating children with unilateral hearing loss, with significant focus on cochlear implantation, in terms of reviewing the key points of the history, including the duration of deafness, outlining the recommended audiometric testing battery, and discussing issues related to imaging of the auditory system and related anatomy. In addition, a comprehensive and up-to-date summary of outcomes in terms of speech perception, sound localization, and quality of life for both the child with unilateral hearing loss as well as their parent(s) is reported.


Assuntos
Implante Coclear , Implantes Cocleares , Surdez , Perda Auditiva Unilateral , Percepção da Fala , Criança , Humanos , Perda Auditiva Unilateral/diagnóstico , Perda Auditiva Unilateral/cirurgia , Qualidade de Vida , Resultado do Tratamento , Implante Coclear/métodos , Surdez/diagnóstico , Surdez/cirurgia
5.
Cochlear Implants Int ; 22(5): 265-269, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33784936

RESUMO

BACKGROUND: Percutaneous bone anchored hearing systems have been used effectively for over forty years with low rates of complications. Minimally Invasive Ponto Surgery (MIPS) is a surgical technique performed through a puncture hole that has been reported to minimize soft tissue trauma and decrease operative time. Due to it being a relatively new procedure there remains a paucity of pediatric outcomes data. METHODS: Pediatric patients from two tertiary pediatric otolaryngology centers between 2016 and 2019 who underwent MIPS were included in this study. Charts were retrospectively reviewed for indications for surgery, implant and abutment type, overlying skin thickness, skin-to-skin time, Holgers score at three, six and twelve months, revision surgery and time to abutment fitting. RESULTS: Fourteen patients, two with bilateral procedures met inclusion criteria (mean age = 8.07 ± 2.87years). The mean overlying skin thickness was 5.13 ± 3.18mm. 9.44% of visits had an adverse skin reactionOne patient required surgery forskin overgrowth. One implant loss (6.3%) was reported, following trauma to the abutment. Mean MIPS skin to skin times were 12.4 ± 2.6 min, markedly different that the Baha® Attract and Connect which were 56 and 53 min, respectively. CONCLUSION: This study represents the largest pediatric MIPS cohort to date, and our results are similar to published adult studies.


Assuntos
Prótese Ancorada no Osso , Implante Coclear , Auxiliares de Audição , Adulto , Criança , Pré-Escolar , Humanos , Procedimentos Cirúrgicos Minimamente Invasivos , Estudos Retrospectivos
6.
Cochlear Implants Int ; 21(6): 353-357, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32657236

RESUMO

Objective: To identify the rate of cochlear implantation (CI) re-implantation and assess audiologic outcomes. Methods: Demographic, audiometric, radiographic, and clinical data were collected from the medical records of the first 834 pediatric patients (age < 18) who underwent CI at a tertiary-care center. Results: Reviewing the first 834 pediatric patients who underwent CI between 1986 and 2013, 33 (4%) children have required re-implantation. Seven (0.8%) of these required a second re-implantation, for a total of 40 total revision surgeries (4.8%) and 21.1% of patients who underwent revision required multiple re-implantations. The mean age at initial CI was 3.5 years old, with identification of the failure an average of 2.7 years later (range, 0.1-10.1 years). The most common indications for re-implantation CI were unknown etiology (58%), vendor recall (18%), and trauma (9%). Twenty-three (88.5%) of the 26 patients who underwent only one re-implantation surgery achieved a complete insertion with both procedures. Eleven (91.7%) of 12 patients who had open set speech after their initial procedure maintained this after re-implantation surgery. Eight (38.1%) of 21 patients who did not have open-set speech after their initial implantation achieved open set speech with CI re-implantation. Conclusion: CI re-implantation is not common in the pediatric population. However, given the time-sensitive nature of speech/language development in children, with the right indications, CI re-implantation can be performed safely without compromising audiologic outcomes. However, re-implanted patients have an increased risk they will require re-implantation again in the future.


Assuntos
Implante Coclear/efeitos adversos , Implantes Cocleares/estatística & dados numéricos , Surdez/cirurgia , Falha de Prótese/efeitos adversos , Reoperação/estatística & dados numéricos , Audiometria , Criança , Linguagem Infantil , Pré-Escolar , Surdez/fisiopatologia , Feminino , Humanos , Masculino , Estudos Retrospectivos , Percepção da Fala , Centros de Atenção Terciária
8.
ACS Med Chem Lett ; 9(4): 354-358, 2018 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-29670700

RESUMO

The identification and optimization of the first activators of fast skeletal muscle are reported. Compound 1 was identified from high-throughput screening (HTS) and subsequently found to improve muscle function via interaction with the troponin complex. Optimization of 1 for potency, metabolic stability, and physical properties led to the discovery of tirasemtiv (25), which has been extensively characterized in clinical trials for the treatment of amyotrophic lateral sclerosis.

9.
Artigo em Inglês | MEDLINE | ID: mdl-28109477

RESUMO

OBJECTIVE: A significant proportion of children with congenital hearing loss who are candidates for cochlear implants (CIs) may have inner ear malformations (IEMs). Surgical and speech outcomes following CI in these children have not been widely reported. METHODS: The charts of children who were evaluated for a CI between 1/1/1986 and 12/31/2014 at a university-based tertiary level pediatric cochlear implant center were reviewed. Principal inclusion criteria included (i) age 1-18 years, (ii) history of bilateral severe to profound sensorineural hearing loss, and (iii) limited benefit from binaural amplification. Exclusion criteria included (i) underlying diagnosis of neurodevelopmental disorder and (ii) lack of follow up for speech assessment if a CI was performed. The following outcome measures were reviewed: (i) imaging findings with magnetic resonance imaging or high resolution computed tomography, (ii) intraoperative complications, and (iii) speech perception categorized as the ability to perceive closed set, open set, or none. RESULTS: The prevalence of IEMs was 27% (102 of 381), of which 79% were bilateral. Cochlear dysplasia accounted for 30% (40 of 136) of the anomalies. Seventy-eight of the 102 patients received a CI (78%). Surgery was noted to be challenging in 24% (19 of 78), with a perilymphatic gusher being the most common intraoperative finding. Cochlear dysplasia, vestibular dysplasia and cochlear nerve hypoplasia were associated with poor speech perception (open OR closed set speech recognition scores, 0-23%), although the outcomes in children with enlarged vestibular aqueduct were similar to those of children with normal inner ear anatomy (65%). CONCLUSIONS: Cochlear implantation is safe in children with IEMs. However, the speech perception outcomes are notably below those of patients with normal anatomy, with the exception of when an enlarged vestibular aqueduct is present.


Assuntos
Implante Coclear/métodos , Implantes Cocleares , Orelha Interna/anormalidades , Perda Auditiva Neurossensorial/cirurgia , Doenças do Labirinto/cirurgia , Adolescente , Criança , Pré-Escolar , Implante Coclear/efeitos adversos , Feminino , Perda Auditiva Neurossensorial/congênito , Humanos , Lactente , Complicações Intraoperatórias , Doenças do Labirinto/congênito , Imageamento por Ressonância Magnética , Masculino , Prevalência , Percepção da Fala/fisiologia , Tomografia Computadorizada por Raios X , Resultado do Tratamento
10.
Otol Neurotol ; 37(8): 1071-6, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27525620

RESUMO

OBJECTIVES: 1) To describe the technique for transcanal endoscopic management of congenital ossicular chain fixation. 2) To highlight the utility and outcomes of the endoscopic approach for management of congenital ossicular fixation. STUDY DESIGN: Retrospective patient series. SETTING: Academic tertiary pediatric hospital. PATIENTS: Pediatric patients (age 6-12) undergoing transcanal endoscopic management of congenital ossicular fixation from May 2014 to December 2014. INTERVENTIONS: A transcanal endoscopic approach was used in eight procedures. Ossicular chain pathology was managed with either mobilization, ossiculoplasty with a stapes prosthesis, or incus interposition. MAIN OUTCOME MEASURES: Pure-tone averages, speech reception thresholds, and speech discrimination scores were recorded pre- and postoperatively for each subject. Preoperative computed tomography evaluations were compared to intraoperative findings for each subject. RESULTS: An improvement in the pure-tone average, as well as air-bone gap, was noted after six of eight procedures. No patients experienced a complication or a reduction in their bone conduction hearing. The chorda tympani nerve was preserved in all eight patients. Conversion to open approach was not necessary for any of the eight procedures performed. CONCLUSION: The transcanal endoscopic approach was successful in improving hearing in pediatric patients with congenital ossicular fixation that involves any of the three ossicles. An endoscopic transcanal approach provides an alternative method to manage congenital ossicular pathology with the advantage of providing excellent visualization and the avoidance of a postauricular incision.


Assuntos
Ossículos da Orelha/anormalidades , Ossículos da Orelha/cirurgia , Cirurgia Endoscópica por Orifício Natural/métodos , Procedimentos Cirúrgicos Otológicos/métodos , Condução Óssea/fisiologia , Criança , Otopatias/congênito , Otopatias/cirurgia , Feminino , Audição , Humanos , Masculino , Prótese Ossicular , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Resultado do Tratamento
11.
Otol Neurotol ; 36(10): 1633-7, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26536413

RESUMO

OBJECTIVE: 1) To characterize pediatric cochlear implant performance in patients with hearing loss secondary to bacterial meningitis. 2) To evaluate performance differences in patients with and without labyrinthitis ossificans (LO). STUDY DESIGN: Retrospective case review. SETTING: A large university-based multidisciplinary cochlear implant program. PATIENTS: Forty-nine patients with hearing loss from bacterial meningitis who received cochlear implants from 1991 to 2011. Thirty-nine patients had adequate data for analysis. INTERVENTION: Cochlear implantation with postoperative performance evaluation. MAIN OUTCOME MEASURE(S): Speech perception category (SPC). RESULTS: Nineteen (48.7%) patients had intraoperative evidence of LO. Fourteen patients (70.0%) without LO compared with seven (36.8%) with LO developed open-set speech after implantation. There was a trend toward better postimplant SPC outcomes in patients without LO that did not reach statistical significance (p = 0.17). The presence of LO negatively correlated with classroom placement (p < 0.05). Analysis of each group individually demonstrated statistically significant improvement in pre- versus postimplant SPC outcomes (p < 0.001). CONCLUSION: The presence of LO may negatively affect performance in pediatric patients receiving a cochlear implant for hearing loss secondary to bacterial meningitis.


Assuntos
Implante Coclear , Perda Auditiva/cirurgia , Labirintite/epidemiologia , Meningites Bacterianas/complicações , Percepção da Fala , Adolescente , Criança , Implantes Cocleares , Feminino , Perda Auditiva/microbiologia , Perda Auditiva/patologia , Humanos , Lactente , Labirintite/microbiologia , Masculino , Estudos Retrospectivos , Fala , Resultado do Tratamento
12.
Laryngoscope ; 125(5): 1189-97, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25533791

RESUMO

OBJECTIVES/HYPOTHESIS: Determine if the neuronal pathfinding cues resulting from Eph/ephrin interaction in the inner ear play a role in establishing the tonotopic innervation of the cochlea. STUDY DESIGN: Protein expression of Ephs and ephrins was evaluated in the inner ear of mice and chicks. Subsequently, in vitro, in vivo, and functional electrophysiologic studies were performed to indicate that Ephs and ephrins play a role regulating the normal innervation patterns in the mouse inner ear. METHODS: Eph and ephrin protein expression was identified in the inner ear by western blotting and localized by fluorescence immunohistochemistry and X-gal staining. Eph/ephrin effects on neurite outgrowth was assessed via co-culture with EphB2 expressing COS-1 cells. Anatomic effects of disrupting Eph/ephrin signaling on cochlear innervation were determined with lipophilic dye tracing and functional effects with auditory brainstem response (ABR). RESULTS: Expression of several different Ephs and ephrins were found in the inner ear of chicks and mice. The changes in ephrin-A2 immunoreactivity after gentamicin ototoxicity coincide with the spatio-temporal pattern of hair cell loss and regeneration in the chick cochlea. EphB2 inhibited outgrowth of spiral ganglion cell neurites. Knockout mice with null function of EphB1, EphB2, and EphB3 demonstrated abnormal inner ear innervation and elevated ABR thresholds, indicating hearing loss. CONCLUSIONS: Ephrin-A2 may be involved in the guidance of ganglion cells to hair cells in the chick. Disruption of Eph/ephrin signaling results in abnormal innervation and hearing loss, suggesting that these proteins play a role in establishing normal innervation patterns in the mouse cochlea. LEVEL OF EVIDENCE: NA


Assuntos
Implantes Cocleares , Surdez/cirurgia , Efrinas/biossíntese , Células Ciliadas Auditivas/metabolismo , Receptores da Família Eph/biossíntese , Gânglio Espiral da Cóclea/metabolismo , Animais , Animais Recém-Nascidos , Galinhas , Técnicas de Cocultura , Surdez/metabolismo , Surdez/fisiopatologia , Modelos Animais de Doenças , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Camundongos Transgênicos
13.
Laryngoscope ; 124(7): E278-82, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24353053

RESUMO

OBJECTIVES/HYPOTHESIS: Determine if differences in right and left semicircular size account for phenotypic behavior, indicating vestibulopathy in EphB deficient mice. STUDY DESIGN: The diameters of the superior semicircular canals (SCC) were measured. The differences in the right and left superior SCC diameters were analyzed in homozygous EphB2 and EphB3 double knockout mice known to have head bobbing and circling behavior. Results were compared to similar analysis in wild type controls that displayed no signs of vestibulopathy. METHODS: Axial frozen sections through the superior (SCC) were analyzed by light microscopy; and the diameters of the left and right canals were measured in µm for both EphB2 and EphB3 double knockout mice, as well as in wild type control mice. The differences in diameter between the left and right superior SCC was determined for each animal. RESULTS: Overall, the EphB2 and EphB3 double knockout mice had smaller superior SCC diameters compared to wild type (109.0±21.4 µm vs. 185.0±5.2 µm (P<0.0001). The mean difference in left and right diameter of the superior SCC of EphB2/EphB3 double knockout mice was 29.0±8.7 µm; in wild-type controls this difference was 6.0±5.1 µm (P=0.002). In addition, the direction of circling appeared to be independent of the laterality of the smaller (or larger) superior SCC. CONCLUSION: Mice deficient in EphB2/EphB3 signaling have smaller superior SCC and asymmetry in lumen sizes between the left and right sides. The laterality of the larger versus smaller is not correlated with the direction of circling behavior. LEVEL OF EVIDENCE: N/A.


Assuntos
Comportamento Animal , Receptor EphB2/deficiência , Canais Semicirculares/patologia , Doenças Vestibulares/psicologia , Animais , Modelos Animais de Doenças , Camundongos , Camundongos Knockout , Fenótipo , Receptor EphB2/genética , Canais Semicirculares/fisiopatologia , Transdução de Sinais , Doenças Vestibulares/metabolismo , Doenças Vestibulares/patologia
14.
Expert Opin Pharmacother ; 14(17): 2399-405, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24093464

RESUMO

INTRODUCTION: Ciprofloxacin 0.3% with dexamethasone 0.1% (ciprofloxacin/dexamethasone) is an ototopical preparation for acute otitis externa, otorrhea with tympanostomy tubes, and is frequently used to treat chronic suppurative otitis media (CSOM). The advantage of topical therapy is the ability to deliver higher concentration of antibiotics to the treatment site when compared with oral or parenteral antibiotics. The delivery of a high concentration of antibiotics significantly decreases treatment failure and makes the development of resistant organisms unlikely. Previous ototopical preparations contained antibiotics such as aminoglycosides that are known to be ototoxic making treatment of otic infections without an intact tympanic membrane difficulty. AREAS COVERED: A literature search of PubMed was performed as the basis for a literature-based discussion on the clinical efficacy of ciprofloxacin/dexamethasone compared to oral antibiotics and ototopical therapy without a steroid component. The potential ototoxicity of ototopical therapies is discussed, including evidence demonstrating the lack of ototoxicity of fluoroquinolone and dexamethasone containing drops. EXPERT OPINION: Because multiple studies have demonstrated that fluoroquinolones are not ototoxic, fluoroquinolone ototopical drops should be a first-line treatment for otorrhea without an intact membrane. The addition of dexamethasone 0.1% to ciprofloxacin 0.3% has been shown to decrease granulation tissue, improve clinical cure and achieve greater rates of bacterial eradication when compared to ciprofloxacin 0.3% alone.


Assuntos
Antibacterianos/administração & dosagem , Ciprofloxacina/administração & dosagem , Dexametasona/administração & dosagem , Glucocorticoides/administração & dosagem , Otite Média/tratamento farmacológico , Animais , Combinação de Medicamentos , Humanos
15.
Int J Pediatr Otorhinolaryngol ; 77(7): 1099-102, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23684567

RESUMO

OBJECTIVE: To compare outcomes of stapedectomy in patients with congenital stapes fixation versus juvenile otosclerosis. METHODS: A retrospective chart review was performed from January 1, 1999 until January 1, 2011 to identify patients under 18 years old who underwent a stapedectomy. Age, gender, pre- and postoperative audiograms, intraoperative findings including etiology of stapes fixation, prosthesis type, and complications were recorded. RESULTS: Twenty-two children were identified who had undergone a stapedectomy (two patients underwent sequential bilateral surgery) resulting in a total of 24 ears. The cause of fixation included juvenile otosclerosis (n=7) and congenital stapes fixation (n=17). The overall mean pre-operative air-bone gap (ABG) was 34.7 dB (SD: 13.5) compared to a postoperative mean ABG of 9.0 (SD: 9.3) (p<0.001). The mean postoperative ABG of 9.6 (SD: 10.5) in the congenital stapes fixation group was similar to the mean postoperative ABG of 7.2dB (SD: 5.4) in children with juvenile otosclerosis (p=0.6). Two patients developed delayed profound sensorineural hearing loss approximately two weeks after surgery. One patient with profound sensorineural hearing loss recovered to a profound mixed hearing loss with a speech discrimination score of 80%. CONCLUSIONS: Pediatric stapedectomy has comparable results to stapedectomy in adults regardless of the cause of stapes fixation; however, delayed sensorineural hearing loss may be higher in the pediatric population.


Assuntos
Otosclerose/cirurgia , Cirurgia do Estribo/métodos , Estribo/anormalidades , Adolescente , Audiometria , Criança , Feminino , Humanos , Masculino , Complicações Pós-Operatórias , Estudos Retrospectivos , Cirurgia do Estribo/efeitos adversos , Resultado do Tratamento
16.
Arch Otolaryngol Head Neck Surg ; 138(10): 969-72, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23069828

RESUMO

OBJECTIVE: To identify and classify laryngeal clefts in a novel mouse model. DESIGN: In vivo animal study. SETTING: Academic research laboratory. SUBJECTS: 129/CD1 mice with the ephrin-B2 gene disrupted by the ß-galactosidase (lacZ) gene were humanely killed at embryonic day 18 (E18) and evaluated for the presence and characterization of a laryngeal cleft. Homozygous and heterozygous lacZ knockout mice as well as wild-type littermates were evaluated. MAIN OUTCOME MEASURES: Microsurgical dissection of the oral cavity and pharynx allowed for a pseudoendoscopic view of the larynx to determine the presence or absence of a cleft. The specimens were also histologically sectioned and examined for characterization and classification of the cleft. RESULTS: A laryngeal cleft was identified in 12 of 27 ephrin-B2 homozygous lacZ knockout mice (44%). Laryngeal clefts were not identified in heterozygous ephrin-B2 knockout mice or in wild-type littermates. CONCLUSIONS: Disruption of ephrin-B2 reverse signaling results in laryngeal clefts in lacZ knockout mice. This presents a novel mouse model in which future investigations into etiology of laryngeal clefts may be examined.


Assuntos
Anormalidades Congênitas/genética , Laringe/anormalidades , Animais , Anormalidades Congênitas/metabolismo , Anormalidades Congênitas/patologia , Modelos Animais de Doenças , Efrina-B2/genética , Efrina-B2/metabolismo , Óperon Lac , Laringe/metabolismo , Laringe/patologia , Camundongos , Camundongos Knockout
17.
Nat Med ; 18(3): 452-5, 2012 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-22344294

RESUMO

Limited neural input results in muscle weakness in neuromuscular disease because of a reduction in the density of muscle innervation, the rate of neuromuscular junction activation or the efficiency of synaptic transmission. We developed a small-molecule fast-skeletal-troponin activator, CK-2017357, as a means to increase muscle strength by amplifying the response of muscle when neural input is otherwise diminished secondary to neuromuscular disease. Binding selectively to the fast-skeletal-troponin complex, CK-2017357 slows the rate of calcium release from troponin C and sensitizes muscle to calcium. As a consequence, the force-calcium relationship of muscle fibers shifts leftwards, as does the force-frequency relationship of a nerve-muscle pair, so that CK-2017357 increases the production of muscle force in situ at sub-maximal nerve stimulation rates. Notably, we show that sensitization of the fast-skeletal-troponin complex to calcium improves muscle force and grip strength immediately after administration of single doses of CK-2017357 in a model of the neuromuscular disease myasthenia gravis. Troponin activation may provide a new therapeutic approach to improve physical activity in diseases where neuromuscular function is compromised.


Assuntos
Cálcio/metabolismo , Músculo Esquelético/metabolismo , Doenças Neuromusculares/metabolismo , Troponina C/agonistas , Troponina C/metabolismo , Adenosina Trifosfatases/metabolismo , Animais , Bovinos , Humanos , Imidazóis/química , Imidazóis/uso terapêutico , Terapia de Alvo Molecular , Contração Muscular/efeitos dos fármacos , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/patologia , Miastenia Gravis/tratamento farmacológico , Miastenia Gravis/metabolismo , Miastenia Gravis/patologia , Miosinas/isolamento & purificação , Miosinas/metabolismo , Doenças Neuromusculares/tratamento farmacológico , Doenças Neuromusculares/patologia , Pirazinas/química , Pirazinas/uso terapêutico , Coelhos , Ratos , Troponina/metabolismo , Troponina/fisiologia
18.
Spine (Phila Pa 1976) ; 37(2): E79-85, 2012 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-21629171

RESUMO

STUDY DESIGN: Controlled laboratory study. OBJECTIVE: To evaluate the biomechanical characteristics of a new expandable interbody cage in single-segment posterior lumbar interbody fusion (PLIF) using cadaveric lumbar spines. SUMMARY OF BACKGROUND DATA: One of the popular methods of treating lumbar spine pathologies involves a posterior lumbar interbody fusion using bilateral interbody nonexpandable cages. However, this method can require extensive bony removal and nerve root retraction. Expandable interbody cages may decrease the risk associated with PLIFs. METHODS: Biomechanical testing was performed on 5 fresh frozen L4/L5 mobile functional spinal units using a custom testing system that permits 6 df and a digital video digitizing system. The specimens were tested intact, postdiscectomy, after interbody cage placement, and after cage placement and pedicle screw fixation. Each specimen was tested from 0.5 to 8.0 N·m for extension, flexion, lateral bending, and rotation, and from 5 to 300 N for axial compression. The angular displacement, stiffness, disc height, and sagittal alignment were determined. RESULTS: When the cage was supplemented with pedicle screw fixation, the mean angular displacement for rotation and lateral bending was significantly less than all other conditions (P < 0.05). The percentage range of motion (% ROM) showed a statistically significant decrease in lateral bending (P < 0.05) for cage alone vs. postdiscectomy. For the pedicle screw construct, rotation showed a significantly lower percentage ROM compared with all other constructs (P < 0.05), and lateral bending and extension-flexion showed a significantly lower percentage ROM compared with postdiscectomy (P < 0.05). For all motions, stiffness of the cage and pedicle screw construct was greater than intact, with only rotation showing a statistically significant increase (P < 0.05). Anterior disc height was restored to intact after cage alone (P < 0.05). Sagittal alignment did not show statistically significant differences. CONCLUSION: PLIF using expandable lumbar interbody cage requires pedicle screw fixation.


Assuntos
Fenômenos Biomecânicos/fisiologia , Fixadores Internos/normas , Deslocamento do Disco Intervertebral/cirurgia , Vértebras Lombares/cirurgia , Procedimentos Neurocirúrgicos/instrumentação , Fusão Vertebral/instrumentação , Idoso , Idoso de 80 Anos ou mais , Humanos , Fixadores Internos/efeitos adversos , Deslocamento do Disco Intervertebral/patologia , Deslocamento do Disco Intervertebral/fisiopatologia , Vértebras Lombares/fisiologia , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/efeitos adversos , Procedimentos Neurocirúrgicos/métodos , Fusão Vertebral/efeitos adversos , Fusão Vertebral/métodos
19.
Laryngoscope ; 121(7): 1541-7, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21647913

RESUMO

OBJECTIVE: To determine the expression patterns of B ephrins and Ephs in the cochlea and identify functional consequences of disruption of ephrin B/Eph B interactions in both cultured spiral ganglion neurons and in the cochlea of live animals. STUDY DESIGN: The expression patterns of various B ephrins and Ephs were determined in mice with Lac-Z mutation. Mice with null function of individual B ephrin and Eph proteins and those with multiple knockouts were studied for cochlear innervation patterns. METHODS: Mice with B ephrins and Ephs disrupted with the ß-galactosidase gene were sacrificed at P6, and their cochleae isolated and processed for Lac-Z staining to determine expression of these proteins in cochlear tissue. Spiral ganglion cells from wild-type as well as ephrin B1 knockout mice were isolated and cocultured with Eph B2 expressing Cos1 cells and neurite lengths were determined. Fluorescent lipophillic dyes were used to label spiral ganglion cell nerve fibers to determine cochlear innervation patterns in wild-type and knockout mice. RESULTS: Eph B1, B2, and ephrin B2 but not B3 was expressed in the cochlea. Eph B2 inhibited outgrowth of spiral ganglion cell axons from wild-type mice, but not from ephrin B1 knockout mice in culture. Knockout mice with null function of ephrin B1 alone or Eph B1, Eph B2, Eph B3 in combination demonstrated abnormal innervation patterns in the organ of Corti. CONCLUSIONS: Disruption of B ephrins and Ephs results in functional consequences in spiral ganglion cells, suggesting that these proteins play a role in establishing normal innervation patterns in the cochlea.


Assuntos
Cóclea/inervação , Cóclea/metabolismo , Nervo Coclear/metabolismo , Efrina-B1/metabolismo , Efrina-B2/metabolismo , Receptores da Família Eph/metabolismo , Animais , Animais Recém-Nascidos , Biomarcadores/metabolismo , Nervo Coclear/fisiologia , Efrina-B1/genética , Efrina-B2/genética , Regulação da Expressão Gênica , Camundongos , Camundongos Knockout , Modelos Animais , Distribuição Aleatória , Receptores da Família Eph/genética , Sensibilidade e Especificidade , Transdução de Sinais , Gânglio Espiral da Cóclea/metabolismo , Gânglio Espiral da Cóclea/fisiologia , Osso Temporal/metabolismo
20.
Otol Neurotol ; 32(6): 956-61, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21659925

RESUMO

OBJECTIVE: To evaluate speech perception after cochlear implantation in children with cochlear nerve absence or deficiency. METHODS: A retrospective case review was performed to identify children who underwent cochlear implantation with cochlear nerve absence or deficiency. The cochlear nerve was evaluated by high-resolution three-dimensional T2-weighted fast spin echo MR in the oblique sagittal and axial planes. A deficient cochlear nerve was defined as a cochlear nerve that is smaller in diameter when compared with the adjacent facial nerve in the midportion of the internal auditory canal. The cochlear nerve was considered absent if there was no imaging evidence of a cochlear nerve. Speech awareness threshold and the speech perception category score were used to measure speech perception after cochlear implantation. RESULTS: Seven children who underwent cochlear implantation in an ear without imaging evidence of a cochlear nerve were identified. One child developed early closed-set speech recognition. The other 6 children developed only speech detection or pattern perception. Two children underwent cochlear implantation with a deficient cochlear nerve. One developed consistent closed-set word recognition and the other developed early closed-set word recognition. The mean follow-up time for all patients was 3.8 years (range, 1.1-7.1 yr). CONCLUSION: Cochlear nerve deficiency is not an uncommon cause for profound sensorineural hearing loss and presents a challenge in the decision-making process regarding whether to proceed with a cochlear implant. Children with a deficient but visible cochlear nerve on magnetic resonance image can expect to show some speech understanding after cochlear implantation; however, these children do not develop speech understanding to the level of implanted children with normal cochlear nerves. Children with an absent cochlear nerve determined by magnetic resonance imaging can be expected to have limited postimplantation sound and speech awareness.


Assuntos
Implante Coclear , Nervo Coclear/anormalidades , Perda Auditiva/cirurgia , Percepção da Fala/fisiologia , Criança , Pré-Escolar , Implantes Cocleares , Feminino , Seguimentos , Perda Auditiva/congênito , Perda Auditiva/fisiopatologia , Humanos , Lactente , Masculino , Estudos Retrospectivos , Resultado do Tratamento
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