Oral aspiration, type 1 laryngeal cleft, and respiratory tract infections in canadian inuit children.

Canadian Inuit infants suffer the highest rate of lower respiratory tract infections (LRTI's) in the world. The causes of this are incompletely understood. The primary objective of this study was to determine whether there exists an association between respiratory morbidity and oral aspiration in Inuit children. A retrospective chart review was conducted including children from Nunavut who underwent Video Fluoroscopic Swallowing Study between the years of 2001 to 2015. The primary outcome was hospitalization for LRTI. We hypothesized that infants found to have aspiration would experience a higher rate of admissions for LRTI than those with normal swallowing studies. One-hundred and twenty-seven patients were identified, of whom 94 were included. Fifty-six percent of patients had an abnormal swallowing study. Compared with patients with normal swallowing, the incidence rate of LRTI was higher in patients with aspiration (incidence rate ratio [IRR] = 1.51; 95% confidence interval [CI] = 1.23-1.87) and in patients with penetration (IRR = 1.40; 95% CI = 1.11-1.76). Fourteen percent of patients had confirmed laryngeal cleft; patients with confirmed presence of this also had a higher incidence rate of LRTI (IRR = 1.66; 95% CI = 1.32-2.07). The incidence of abnormal swallowing study showed an 11-fold variation across the five regions in Nunavut, with the highest prevalence in west Qikiqtani Region (Baffin Island). We conclude that swallowing dysfunction is not only prevalent amongst Canadian Inuit but clinically significant. This is the first study to demonstrate an association between swallowing dysfunction and respiratory morbidity in this population. Geographic distribution patterns and high rates of laryngeal cleft may point to a potential genetic etiology for what remains at this point, idiopathic swallowing dysfunction.

Characterization of a novel molluskan tyrosine kinase receptor that inhibits neurite regeneration.

Receptor tyrosine kinases play many important roles in neuronal signaling including regulating neurite outgrowth. We have identified a novel receptor tyrosine kinase, neurite outgrowth regulating kinase (nork) from Aplysia californica. A fragment of this kinase was also identified in another mollusk, Lymnaea. The kinase domain is equally homologous to the Ret (rearranged during transformation) and fibroblast growth factor receptor families, but the extracellular domain is entirely novel, suggesting that it binds a nonconserved ligand. Overexpression of neurite outgrowth regulating kinase, but not a kinase dead form, causes a reduction in neurite outgrowth of Aplysia sensory neurons. Thus, we have identified a novel receptor tyrosine kinase implicated in regulating neurite outgrowth.