VEMPs and Dysautonomia Assessment in Definite Cerebellar Ataxia, Neuropathy, Vestibular Areflexia Syndrome (CANVAS): a Case Series Study.

Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a recently described slowly progressive ataxia with severe imbalance due to the compromise of three of the four sensory inputs for balance, leaving only vision unaffected. Bilateral vestibulopathy is present but saccular and utricular function, measured by vestibular evoked myogenic potentials (VEMPs), has not been widely studied in these patients. Dysautonomia has been reported but is not among the diagnostic criteria. We performed a database analysis to identify patients evaluated between 2003 and 2019 with probable diagnosis of CANVAS by using key words "bilateral vestibulopathy and/or cerebellar ataxia and/or sensory polyneuropathy." Five out of 842 met all conditions. Patients underwent neurological/neurootological exam, brain MRI, visually enhanced vestibulo-ocular reflex (VVOR) exam by high-speed video-oculography using video-Head Impulse Test (vHIT), VEMPs, neurophysiological studies, and genetic tests to exclude other causes of ataxia. Dysautonomia was addressed by the standardized survey of autonomic symptoms. All patients had clinically definite CANVAS as brain MRI showed vermal cerebellar atrophy, neurophysiological studies showed a sensory neuronopathy pattern (absent sensory action potentials), VVOR was abnormal bilaterally, and genetic tests ruled out other causes of ataxia including SCA 3 and Friedreich ataxia. Patients had at least 3 dysautonomic symptoms, including xerostomia/xerophthalmia (5/5). VEMP results varied among patients, ranging from normal to completely abnormal. We found inconsistent results with VEMPs. The utilization of VEMPs in more CANVAS cases will determine its utility in this syndrome. Dysautonomia may be included in the diagnostic criteria.

Continuous intraocular pressure monitoring in patients with obstructive sleep apnea syndrome using a contact lens sensor.

PURPOSE: To analyse nocturnal intraocular pressure (IOP) fluctuations in patients with obstructive sleep apnea syndrome (OSAS) using a contact lens sensor (CLS) and to identify associations between the OSAS parameters determined by polysomnographic study (PSG) and IOP changes. METHOD: Prospective, observational study. Twenty participants suspected of having OSAS were recruited. During PSG study, IOP was monitored using a CLS placed in the eye of the patient. The patients were classified according to the apnea-hypopnea index (AHI) in two categories, severe (>30) or mild/moderate (<30) OSAS. We evaluated several parameters determined by the IOP curves, including nocturnal elevations (acrophase) and plateau times in acrophase (PTs) defined by mathematical and visual methods. RESULTS: The IOP curves exhibited a nocturnal acrophase followed by PTs of varying extents at which the IOP remained higher than daytime measurement with small variations. We found significant differences in the length of the PTs in patients with severe OSAS compared to those with mild/moderate disease (P = 0.032/P = 0.028). We found a positive correlation between PTs and OSAS severity measured by the total number of apneic events (r = 0.681/0.751 P = 0.004/0.001) and AHI (r = 0.674/0.710, P = 0.004/0.002). Respiratory-related arousal and oxygen saturation also were associated significantly with the IOP PT length. CONCLUSIONS: Periods of nocturnal IOP elevation lasted longer in severe OSAS patients than those with mild/moderate OSAS and correlate with the severity of the disease. The length of the nocturnal PT is also associated to respiratory parameters altered in patients with OSAS.

The role of enamelysin (MMP-20) in tooth development: systematic review / El papel de la enamelisina (MMP-20) en el desarrollo dentario: revisión sistemática

ABSTRACT. Introduction: ameloblasts are cells responsible for the production and mineralization of the organic matrix of enamel through several stages: pre-secretory, secretory, transition, and maturation. The organic matrix components are produced in the secretory phase. In the maturation phase, the organic component is removed and the mineralization process starts. This process requires the involvement of matrix metalloproteinase 20 (MMP-20), also called enamelysin. Several studies have shown the presence of MMP-20 in tooth development and its relationship to alterations in enamel formation. The objective was: to classify the different studies and laboratory techniques used to demonstrate the involvement of enamelysin in tooth development and its relation to pathologies during enamel formation. Methods: a systematic review was conducted with the following bibliographic databases: PubMed, Science-Direct, Hinari, and SciELO, in order to classify the different studies related to the involvement of MMP-20 in tooth development and the methods to detect its expression, between the years of 2009 and 2014. Results and conclusions: 11 in vitro models show that MMP-20 has specific cleavage sites for enamel matrix proteins. This process is altered by chemical composition, ions, and the presence of hydroxyapatite. Enamel morphology is altered in the knockout models. In human studies, MMP-20 has been associated with increased susceptibility to dental caries, enamel thickness, and dental agenesis.

RESUMEN. Introducción: el ameloblasto es la célula encargada de la producción y mineralización de la matriz orgánica del esmalte. Atraviesa varias etapas: la fase pre-secretora, secretora, de transición y maduración. En la fase secretora se producen los componentes de la matriz orgánica. En la fase de maduración se elimina el componente orgánico y se inicia el proceso de mineralización. Este proceso requiere de la participación de la metaloproteinasa de matriz 20 (MMP-20) o también llamada enamelisina. Diversos estudios demuestran la presencia de MMP-20 en el desarrollo dentario y su relación con alteraciones en la formación del esmalte. El objeto fue clasificar los diferentes estudios y técnicas de laboratorio empleadas que demuestren la participación de enamelisina en el desarrollo dentario y su relación con patologías en la formación del esmalte. Métodos: se realizó una revisión sistemática de la literatura con las siguientes bases bibliográficas: PubMed, Science-Direct, Hinari y SciELO, con el fin de clasificar los diferentes estudios relacionados con la participación de MMP-20 en el desarrollo dental y los métodos utilizados para detectar su expresión, entre los años de 2009 a 2014. Resultados y conclusiones: los modelos in vitro evidencian que MMP-20 tiene sitios específicos de escisión para las proteínas de matriz de esmalte. Este proceso se ve alterado por la composición química, iones, y la presencia de hidroxiapatita. En los modelos knockout la morfología del esmalte está alterada. En los estudios en humanos, se ha relacionado la MMP-20 con una mayor susceptibilidad de caries dental, el grosor completo de esmalte y agenesias dentales.