Binge-like ethanol exposure during the brain growth spurt disrupts the function of retrosplenial cortex-projecting anterior thalamic neurons in adolescent mice.

Ethanol (EtOH) exposure during late pregnancy leads to enduring impairments in learning and memory that may stem from damage to components of the posterior limbic memory system, including the retrosplenial cortex (RSC) and anterior thalamic nuclei (ATN). In rodents, binge-like EtOH exposure during the first week of life (equivalent to the third trimester of human pregnancy) triggers apoptosis in these brain regions. We hypothesized that this effect induces long-lasting alterations in the function of RSC-projecting ATN neurons. To test this hypothesis, vesicular GABA transporter-Venus mice (expressing fluorescently tagged GABAergic interneurons) were subjected to binge-like EtOH vapor exposure on postnatal day (P) 7. This paradigm activated caspase 3 in the anterodorsal (AD), anteroventral (AV), and reticular thalamic nuclei at P7 but did not reduce neuronal density in these areas at P60-70. At P40-60, we injected red retrobeads into the RSC and performed patch-clamp slice electrophysiological recordings from retrogradely labeled neurons in the AD and AV nuclei 3-4 days later. We found significant effects of treatment on instantaneous action potential (AP) frequency and AP overshoot, as well as sex × treatment interactions for AP threshold and overshoot in AD neurons. A sex × treatment interaction was detected for AP number in AV neurons. EtOH exposure also reduced the frequency and amplitude of spontaneous excitatory postsynaptic currents and increased the charge transfer of spontaneous inhibitory postsynaptic currents. These results highlight a novel cellular mechanism that could contribute to the lasting learning and memory deficits associated with developmental EtOH exposure.

Pediatric laryngeal dimensions: an age-based analysis.

BACKGROUND: In children, the cricoid is considered the narrowest portion of the "funnel-shaped" airway. Growth and development lead to a transition to the more cylindrical adult airway. A number of airway decisions in pediatric airway practice are based on this transition from the pediatric to the adult airway. Our primary aim in this study was to measure airway dimensions in children of various ages. The measures of the glottis and cricoid regions were used to determine whether a transition from the funnel-shaped pediatric airway to the cylindrical adult airway could be identified based on images obtained from video bronchoscopy. METHODS: One hundred thirty-five children (ASA physical status 1 or 2) aged 6 mo to 13 yr were enrolled for measurement of laryngeal dimensions, including cross-sectional area (G-CSA), anteroposterior and transverse diameters at the level of the glottis and the cricoid (C-CSA), using the video bronchoscopic technique under general anesthesia. RESULTS: Of the 135 children enrolled in the study, seven patients were excluded from the analysis mainly because of poor image quality. Of the 128 children studied (79 boys and 49 girls), mean values (+/-standard deviation) for the demographic data were age 5.9 (+/-3.3) yr, height 113.5 (+/-22.2) cm and weight 23.5 (+/-13) kg. Overall, the mean C-CSA was larger than the G-CSA (48.9 +/- 15.5 mm(2) vs 30 +/- 16.5 mm(2), respectively). This relationship was maintained throughout the study population starting from 6 mo of age (P < 0.001, r = 0.45, power = 1). The mean ratio for C-CSA: G-CSA was 2.1 +/- 1.2. There was a positive correlation between G- and the C-CSA versus age (r = 0.36, P < 0.001; r = 0.27, P = 0.001, respectively), height (r = 0.34, P < 0.001; r = 0.29, P < 0.001, respectively), and weight (r = 0.35, P < 0.001; r = 0.25, P = 0.003, respectively). No significant gender differences in the mean values of the studied variables were observed. CONCLUSION: In this study of infants and children, the glottis rather than cricoid was the narrowest portion of the pediatric airway. Similar to adults, the pediatric airway is more cylindrical than funnel shaped based on these video bronchoscopic images. Further studies are needed to determine whether these static airway measurements in anesthetized and paralyzed children reflect the dynamic characteristics of the glottis and cricoid in children.

Upper airway dimensions in children using rigid video-bronchoscopy and a computer software: description of a measurement technique.

BACKGROUND: Pediatric airway management decisions are based primarily on results derived from indirect measures of laryngeal and tracheal dimensions. More recent methods could provide more direct information about absolute and relative changes in airway dimensions associated with growth and development. STUDY OBJECTIVES: The aims of this study were (i) to determine whether a 'video-bronchoscopic' measurement method could be used to reliably measure airway dimensions in children and (ii) to provide a preliminary assessment of dimensions of the glottis and cricoid in children of various ages. METHODS: Following approval from the institutional review board, validation experiments were performed to determine whether measurements obtained from the video image from the bronchoscope provided accurate measurements of tubular objects of known dimensions. The reliability of the measurements was determined by using two independent trained observers to measure video-bronchoscopic images of the larynx at the level of the glottis and the cricoid in 11 children. The observers measured the video-bronchoscopic images and airway measurements were obtained in 16 additional children to determine the utility of the measurement method. RESULTS: There was good agreement between the direct and video-bronchoscopic measurement techniques (Bland and Altman plot) for both the cross-sectional area (CSA) and the diameter of objects. The interobserver measures for cricoid and glottis were reproducible as indicated by the concordance correlation coefficient (CCC) for cricoid anteroposterior diameter (CCC = 0.98, r = 0.98, accuracy = 0.99) and transverse diameter (CCC = 0.93, r = 0.8, accuracy = 0.99) as well as for the glottic anteroposterior diameter (r = 0.8, accuracy = 0.8, CCC = 0.6) and the glottic transverse diameter(r = 0.8, accuracy = 0.74, CCC = 0.6). Overall, for the 27 children studied [mean age 73 months (+/-24.7, range 30-140], the mean value of the cricoid CSA [45.3 mm(2) (+/-13.9)] was found to be greater than the glottic CSA [16.2 mm(2) (+/-10.1)]. CONCLUSIONS: The video-bronchoscopic imaging method provided an accurate, reliable measure of pediatric airway dimensions. This technique could be applied to assess absolute and relative airway size associated with growth and development. The relationship between glottic and cricoid dimensions during growth and development in children needs further investigation across various age groups.