Lubricin Protects the Temporomandibular Joint Surfaces from Degeneration

The temporomandibular joint (TMJ) is a specialized synovial joint essential for the mobility and function of the mammalian jaw. The TMJ is composed of the mandibular condyle, the glenoid fossa of the temporal bone, and a fibrocartilagenous disc interposed between these bones. A fibrous capsule, lined on the luminal surface by the synovial membrane, links these bones and retains synovial fluid within the cavity. The major component of synovial fluid is lubricin, a glycoprotein encoded by the gene proteoglycan 4 (Prg4), which is synthesized by chondrocytes at the surface of the articular cartilage and by synovial lining cells. We previously showed that in the knee joint, Prg4 is crucial for maintenance of cartilage surfaces and for regulating proliferation of the intimal cells in the synovium. Consequently, the objective of this study was to determine the role of lubricin in the maintenance of the TMJ. We found that mice lacking lubricin have a normal TMJ at birth, but develop degeneration resembling TMJ osteoarthritis by 2 months, increasing in severity over time. Disease progression in Prg4−/− mice results in synovial hyperplasia, deterioration of cartilage in the condyle, disc and fossa with an increase in chondrocyte number and their redistribution in clusters with loss of superficial zone chondrocytes. All articular surfaces of the joint had a prominent layer of protein deposition. Compared to the knee joint, the osteoarthritis-like phenotype was more severe and manifested earlier in the TMJ. Taken together, the lack of lubricin in the TMJ causes osteoarthritis-like degeneration that affects the articular cartilage as well as the integrity of multiple joint tissues. Our results provide the first molecular evidence of the role of lubricin in the TMJ and suggest that Prg4−/− mice might provide a valuable new animal model for the study of the early events of TMJ osteoarthritis

Look at Mummy: challenges in training parents to deliver a home treatment program for childhood apraxia of speech in a rural Canadian community

Introduction: Children requiring speech pathology services in rural and remote locations face many barriers in accessing adequate services. This has particular consequences for children who need intensive treatment for therapy to be effective, such those with childhood apraxia of speech (CAS). Parent training has been used to overcome speech pathology service delivery barriers for a range of other communication disorders. However, the effectiveness of training parents to deliver a motor-based treatment for CAS within rural and remote contexts has not been evaluated. This study examined the effectiveness and feasibility of training parents in a rural community to use the treatment approach of dynamic temporal and tactile cueing (DTTC) in order to provide more intensive treatment sessions at home. Methods: The study used an experimental single case across behaviours design and parent interviews to evaluate outcomes both quantitatively and qualitatively. The study included four parent- child dyads from a mixed socioeconomic rural community in Canada. Child participants ranged in age from 3 years to 8 years. Child treatment outcomes were measured using an improvement rate difference (IRD) calculation based on percentage of phonemes correct. Fidelity to the treatment protocol was measured using a fidelity score. Results: All parents reported challenges in carrying out the program due to social and behavioural challenges. Parents also reported benefits such as being able to spend more time with their child and learning some useful cueing techniques. Only one of the four participants had a moderate effect size for his target words (RD=57%). Conclusion: While training parents to deliver DTTC may be effective for some parent-child dyads, clinicians are advised that parent training may not be suitable for all families, and parents in rural and remote communities may face particular social circumstances that make following through with an intensive treatment program difficult

Interaction between Foxc1 and Fgf8 during Mammalian Jaw Patterning and in the Pathogenesis of Syngnathia

Syngnathia (bony fusion of the upper and lower jaw) is a rare human congenital condition, with fewer than sixty cases reported in the literature. Syngnathia typically presents as part of a complex syndrome comprising widespread oral and maxillofacial anomalies, but it can also occur in isolation. Most cartilage, bone, and connective tissue of the head and face is derived from neural crest cells. Hence, congenital craniofacial anomalies are often attributed to defects in neural crest cell formation, survival, migration, or differentiation. The etiology and pathogenesis of syngnathia however remains unknown. Here, we report that Foxc1 null embryos display bony syngnathia together with defects in maxillary and mandibular structures, and agenesis of the temporomandibular joint (TMJ). In the absence of Foxc1, neural crest cell derived osteogenic patterning is affected, as osteoblasts develop ectopically in the maxillary prominence and fuse with the dentary bone. Furthermore, we observed that the craniofacial musculature is also perturbed in Foxc1 null mice, which highlights the complex tissue interactions required for proper jaw development. We present evidence that Foxc1 and Fgf8 genetically interact and that Fgf8 dosage is associated with variation in the syngnathic phenotype. Together our data demonstrates that Foxc1 – Fgf8 signaling regulates mammalian jaw patterning and provides a mechanistic basis for the pathogenesis of syngnathia. Furthermore, our work provides a framework for understanding jaw patterning and the etiology of other congenital craniofacial anomalies, including temporomandibular joint agenesis

The adult perceptual limen of syllable segregation in typically developing paediatric speech

Inappropriate gaps between syllables are one of the core diagnostic features of both childhood apraxia of speech and acquired apraxia of speech. However, little is known about how listeners perceive and identify inappropriate pauses between syllables (gap detection). Only one previous study has investigated the perception of inappropriate pauses between syllables in typical adult speakers and no investigations of gap detection in children's speech have been undertaken. The purpose of this research was to explore the boundaries of listener gap detection to determine at which gap length (duration) a listener can perceive that an inappropriate pause is present in child speech. Listener perception of between-syllable gaps was explored in an experimental design study using the online survey platform Qualtrics. Speech samples were collected from two typically developing children and digitally manipulated to insert gaps between syllables. Adult listeners (n = 84) were recruited and could accurately detect segregation on 80% of presentations at a duration between 100 and 125 ms and could accurately detect segregation on 90% of presentations at a duration between 125 and 150 ms. Listener musical training, gender and age were not correlated with accuracy of detection, but speech pathology training was, albeit weakly. Male speaker gender, and strong onset syllable stress were correlated with increased accuracy compared to female speaker gender and weak onset syllable stress in some gap conditions. The results contribute to our understanding of speech acceptability in CAS and other prosodic disorders and moves towards developing standardised criteria for rating syllable segregation. There may also be implications for computer and artificial intelligence understanding of child speech and automatic detection of disordered speech based on between syllable segregation

Endoscopic Posterior Cricoid Split with Costal Cartilage Graft: A Fifteen‐Year Experience

Objective To evaluate outcomes of the endoscopic posterior cricoid split with rib graft (EPCS/RG) procedure in the treatment of subglottic stenosis (SGS), posterior glottic stenosis (PGS), and bilateral vocal fold immobility (BVFI). Study Design Retrospective chart review. Methods Chart review of all patients who underwent EPCS/RG at a single tertiary-care facility between 1999 and 2014. Patients were grouped based on the primary indication for the procedure. Decannulation was the primary endpoint. Secondary endpoints were the number of subsequent airway procedures and length of hospitalization. Results Thirty-three patients were identified; 32 had tracheotomy. Overall decannulation rate was 65.6%. Subgroup analysis demonstrated the following decannulation rates: 53.8% for SGS, 100% for PGS, and 28.6% for BVFI. Fisher exact test found a significant difference in overall decannulation rates between groups (P = 0.002). Operation-specific decannulation rates for patients who never required an open procedure were 23% for SGS, 91.6% for PGS, and 28.6% for BVFI. This difference was also statistically significant (P = 0.001). Multivariate logistic regression analysis found prematurity had a positive correlation with decannulation that approached statistical significance (P < 0.051; odds ratio 6.1; 95% confidence interval 0.99, 37.6). The percentage of patients who underwent repeat airway procedures for the groups was 61.5% for SGS, 16.6 % for PGS, and 14.3% for BVFI. The median length of hospitalization after EPCS/RG was 3 days. Conclusion This represents the largest series of patients who have undergone EPCS/RG and demonstrates that the majority of patients can be decannulated after this procedure. Patients with PGS had the highest operation-specific decannulation rates

Assessing Tracheostomy as a Risk Factor for Hearing Loss in Neonates with Bronchopulmonary Dysplasia

Objectives: This study compares the risk of hearing loss in children with bronchopulmonary dysplasia (BPD) based upon whether the child required tracheostomy. Method: A retrospective chart review was conducted that included all children diagnosed with BPD from 2013–2020 at a single tertiary medical institution. Primary outcome was presence of hearing loss. Children without follow-up audiogram were excluded from analysis. Risk comparison was made using hazard analysis; Cox regression model controlled for exposure to ototoxic medications. Results: There were 177 infants diagnosed with BPD who had sufficient follow-up for inclusion. Thirty-two children (18%) underwent tracheostomy placement. Children with tracheostomy were at significantly higher risk of developing hearing loss, with 13/32 (41%) demonstrating hearing loss during follow-up, compared with 16/145 (11%) of children without tracheostomy, p value \u3c 0.001. Cox regression model found that children with tracheostomy were 5.9 times more likely to develop later onset hearing loss than children without tracheostomy, p value 0.011. Most patients diagnosed with hearing loss were shown to have mild conductive hearing loss. Conclusion: Among children with BPD, those who required tracheostomy were at significantly higher risk of developing hearing loss, including later onset hearing loss. In this study, the hearing loss observed was typically mild and conductive in nature. Families of children with tracheostomy should be counseled regarding this risk and recommendations for otologic and hearing surveillance

Identification of oral clefts as a risk factor for hearing loss during newborn hearing screening

Objective: This study assessed whether children with oral clefts are appropriately classified as at-risk for hearing loss at the time of newborn hearing screening and describes their screening and diagnostic results. Design: Birth certificates were used to identify children with cleft lip and palate or isolated cleft palate born in Washington State from 2008–2013. These were cross-referenced with the state’s Early Hearing Detection, Diagnosis and Intervention (EHDDI) database. Multivariate logistic regression was used to examine associations. Results: Birth records identified 235 children with cleft lip and palate and 116 with isolated cleft palate. Six children were listed as having both diagnoses. Only 138 (39%) of these children were designated as having a craniofacial anomaly in the EHDDI database. Children who were misclassified were less likely to have referred on initial hearing screening, OR 0.3, 95% CI [0.2, 0.5]. Misclassification of risk factor status was also associated with delayed hearing screening past 30 days of age or unknown age at screening, OR 4.4, 95% CI [1.5, 13.3], p = 0.008. Of 50 children with diagnostic results; 25 (50%) had hearing loss: 18 conductive, 2 mixed, and 5 unspecified. Conclusion: A majority of children with oral clefts were misclassified regarding risk factor for hearing loss in the EHDDI database

Molecular cloning and sequence determination of four different cDNA species coding for α-subunits of G proteins from Xenopus laevis oocytes

AbstractA cDNA library preprared from Xenopus laevis oocytes in λgt10 was screened with a mixture of three oligonucleotide probes designed to detect sequences found in different mammalian genes coding for a-subunits of G-proteins. In addition to a clone coding for a Gαo-type subunit previously reported [(1989) FEBS Lett. 244, 188-192] four additional clones have been found coding for different Gα protein subunits. By comparison with mammalian α-subunits, these oocyte cDNAs correspond to two closely related Gas-la, to a Gαi-1 and to a Gαi-3 species. The derived amino acid sequences showed that both Gαs species contain 379 residues, corresponding to the short species without the serine residue and with a calculated Mr of 42720. The Gαi-1 gene encodes a 354 amino acid protein with an Mr, of 39000 and the Gαi-3 encodes an incomplete open reading frame of 345 residues, lacking the first 9 amino acid residues at the NH2, terminus. All these Gα-subunits showed high identity with their respective mammalian counterparts (75–80%), indicating a great degree of conservation through the evolution and the important cellular regulatory function that they play

Acoustic voice characteristics with and without wearing a facemask

Facemasks are essential for healthcare workers but characteristics of the voice whilst wearing this personal protective equipment are not well understood. In the present study, we compared acoustic voice measures in recordings of sixteen adults producing standardised vocal tasks with and without wearing either a surgical mask or a KN95 mask. Data were analysed for mean spectral levels at 0–1 kHz and 1–8 kHz regions, an energy ratio between 0–1 and 1–8 kHz (LH1000), harmonics-to-noise ratio (HNR), smoothed cepstral peak prominence (CPPS), and vocal intensity. In connected speech there was significant attenuation of mean spectral level at 1–8 kHz region and there was no significant change in this measure at 0–1 kHz. Mean spectral levels of vowel did not change significantly in mask-wearing conditions. LH1000 for connected speech significantly increased whilst wearing either a surgical mask or KN95 mask but no significant change in this measure was found for vowel. HNR was higher in the mask-wearing conditions than the no-mask condition. CPPS and vocal intensity did not change in mask-wearing conditions. These findings implied an attenuation effects of wearing these types of masks on the voice spectra with surgical mask showing less impact than the KN95

Clinically small tonsils are typically not obstructive in children during drug-induced sleep endoscopy

OBJECTIVE: To determine whether the degree of lateral pharyngeal wall (LPW) obstruction on pediatric drug-induced sleep endoscopy (DISE) correlates with preprocedure tonsillar hypertrophy score on physical examination, and to determine if clinically small tonsils are obstructive. METHODS: Retrospective review of 154 patients who underwent DISE at a single pediatric tertiary care center over a 4-year period. Inclusion criteria were documentation of Brodsky tonsil score on preoperative physical examination. Exclusion criteria were previous tonsillectomy, adenoidectomy, or adenotonsillectomy. Lateral pharyngeal wall obstruction was graded for each patient from 0 (no obstruction) to 3 (severe obstruction) using a validated pediatric DISE scoring system known as the Chan-Parikh scoring system (C-P). Data were analyzed using multivariate linear regression controlling for age at time of DISE and presence of comorbid conditions. RESULTS: One hundred fifteen patients met criteria for analysis. Median age at DISE was 5.1 years. A moderate positive correlation was calculated between Brodsky score and DISE score, Spearman correlation coefficient 0.55, P = 50% obstruction); and six (9%) had a score of 3 (100% obstruction). CONCLUSION: There is a positive correlation between Brodsky Score and DISE LPW score. The majority of children with sleep-disordered breathing with a Brodsky score of 1 did not demonstrate LPW obstruction. These children may benefit from DISE for identification of alternative sites of upper airway obstructio