Improvement of Mechanical Stability for Single Unit Recording Based on Skull Cap in Living Chinchilla

Three-point head fixation was constructed to provide mechanical stability for single unit recording(SUR)on vestibular sensory system in living chinchilla previously.However,it is no more qualified to this work when the stimulation intensity becomes large because of frequent unit losing and neuron damage,which strongly implies that the mechanical stability has been broken during the stimulation.Here,we constructed a novel hea0 fixation(skull cap assistant head fixation)provided by skull cap on the basis of three-point head fixation in order to improve the mechanical stability for SUR under the stimulation with large magnitude.The large area bone connection is the feature and advantage of this improved method,which directly fixes the tested local nervous tissue and microelectrode in an intact stable system through skull cap except two ear bars and a tube face mask.Our data exhibited that skull cap assistant head fixation could significantly improve the success rate of neural response activity recording in the population of semicircular canal neurons under the stimulation with large intensity(amplitudd 00 deg/s).Based on the analysis of neural response activity and noise base-line during stimulation,our data further indicated that this method could significantly improve the mechanical stability for SUR during high-speed motion stimulation on vestibular system in living chinchilla.Skull cap assistant head fixation extends the application of SUR on vestibular neuron in linear response range and provides a solid foundation for electrophysiological research on vestibular sensory system in fhrther studies.

Inpatient use of racemic epinephrine for children admitted with croup

Background Pediatric patients with croup are frequently admitted if they require two doses of racemic epinephrine(RE)in the emergency department(ED).We aimed to identify factors associated with the need for additional therapy(>2 RE doses)among pediatric patients with croup.Methods We performed a single-center retrospective study of consecutive patients admitted from the ED with a diagnosis of croup between January 1,2011 and December 31,2015.Primary outcome was need for>2 doses of RE.Secondary out-comes included time to third RE and 72-hour return visits.We performed logistic regression to identify factors associated with use of>2 RE doses during hospitalization,and survival analysis to identify time to dosing of 3rd RE from 2nd RE.Results Of 353 included admissions[250(70.8%)males,median age 1.48,interquartile range 0.97-2.51 years],106/353(30.0%)required>2 RE.In univariate logistic regression,only recent use of steroids within 1 day prior to presentation(4.18,1.48-11.83;P=0.007)was associated with need for>2 RE.Survival from third RE was 0.74(95%CI 0.69-0.78),which was similar to the survival at 12 hours(0.70,95%CI 0.65-0.75).Return visits occurred in 19(5.4%)patients,of whom 12/19(63.2%)were given RE.Conclusions Patients hospitalized for croup with recent use of steroids prior to ED presentation have a greater need for>2 RE during hospitalization.The majority who require inpatient RE will do so within 8-12 hours.These data provide informa-tion for risk stratification and duration of monitoring for patients hospitalized with croup.