The output of the hippocampus is inhibited during social behavior in the male rat

We tested the role of C5 segment inspiratory interneurons in transcribing central respiratory drive to phrenic motoneurons and mediating intersegmental reflexes by cross-correlating the spontaneous activity of 26 interneurons with that of the ipsi -and contralateral C5 phrenic nerves in decerebrate cats. There were 10 interneurons that discharged only during inspiration (phrenic burst) and 16 that discharged tonically with increased firing during inspiration. Of the cross-correlograms for 26 of the interneurons with the ipsilateral phrenic, 20 were flat and 2 had peaks centred about time zero, interpreted as a common activation of the interneurons and motoneurons. The cross-correlograms for 4 other interneurons had troughs centred about time zero, interpreted as a synchronous excitation of the interneurons and inhibition of the motoneurons. Of the cross-correlograms for 23 interneurons with the contralateral phrenic, 22 were flat and 1 had a peak centred about time zero, interpreted as a common activation of the interneuron and motoneurons. Nine of ten cross-correlograms between pairs of interneurons were flat; one had a peak centred about time zero. We conclude that, despite their inspiratory modulated discharge patterns, there is no evidence from this study that the C5 segment inspiratory interneurons convey central respiratory drive to C5 phrenic motoneurons.     

人体呼吸道的二级及三级支气管内吸气流动的数值研究

呼吸系统的主要生理机能是在大气和血液之间交换氧气和二氧化碳，其生理过程与呼吸道内的气体流动和输送有密切关系。本文利用数值模拟方法对呼吸道内二级及三级支气管模型内的吸气过程进行数值研究，研究表明：二级支气管的计算结果与现有的实验值吻合很好；在三级支气管内。当人体处于正常吸气流量下，支气管内未发生任何分离现象。但流道几何形状的弯曲和分岔使支气管内出现强烈的二次流现象，主流速度出现倾斜分布及m-型分布特征。从而加大了分岔管内侧壁面及前后侧壁面上的切应力；在三级支气管的末级管内，流量分流不均匀。在计算条件下，中部支气管内的流量与侧部支气管内的流量之比为1．2。     

Effect of Inspiratory Flow on Methacholine Challenge in Children

Regulation of inspiratory flow alters the outcomes of the methacholine (MHC) challenge in adults and cough receptor sensitivity in children. The effect of inspiratory flow on the reproducibility of the MHC challenge in children is unknown. The aim of this study was to evaluate the effect of inspiratory flow alteration on the repeatabilty of the MHC challenge in children with and without asthma. Twenty‐five children undertook the MHC challenge on three different days by using a dosimeter connected to a setup that allowed regulation of inspiratory flow and pattern. Children were randomized to commence the challenges at 20 or 60 L/min, and the last challenge was performed at 20 L/min. The within‐subject standard deviation, 95% range for change, and doubling dose for the differing inspiratory flow (20 vs. 60 L/min) was more than twice that of when inspiratory flow was maintained at 20 L/min for both occasions. The range of the “limits of agreement” of the Bland and Altman plot was smaller when inspiratory flow was constant. For short‐term comparative individual studies in children, inspiratory flow should be regulated. Laboratories and research measuring change in airway hyperrepsonsiveness to MHC should determine and report reproducibility indices of the challenge so airway hyperresponsiveness changes can be interpreted meaningfully.     

Diaphragmatic Ultrasound Correlates with Inspiratory Muscle Strength and Pulmonary Function in Healthy Subjects

Diaphragm ultrasound (DUS) has been used to identify diaphragm dysfunction. However, its correlations with respiratory strength and lung function are unclear, even in healthy patients. A total of 64 healthy patients (30 males) had lung function and inspiratory strength (maximal inspiratory pressure and sniff nasal inspiratory pressure) measured. Gastric and oesophageal pressures were measured in a subgroup (n?=?40). DUS was characterized by mobility (quiet breathing [QB] and deep breathing [DB]) and thickness (at functional residual capacity [Th_FRC] and total lung capacity [Th_TLC]). We calculated the thickening fraction (TF). During QB, DUS was similar between sexes. However, during DB, females had lower mobility, thickness and TF than males. Mobility at DB, Th_TLC and TF significantly correlated with lung function and inspiratory strength. These correlations were affected by sex. DUS correlated with inspiratory gastric pressure. In healthy patients, DUS correlated with lung function and inspiratory strength during DB. Significant differences between genders were noticeable when DUS was performed during DB.     

稳定期慢性阻塞性肺疾病患者的气道阻力与运动相关呼吸困难肺功能参数的关系

目的观察稳定期慢性阻塞性肺疾病(COPD)患者的各项气道阻力(Raw)参数与运动相关呼吸困难肺功能参数的相关关系。方法前瞻性纳入上海交通大学附属胸科医院和第一人民医院门诊稳定期COPD患者180例,根据慢性阻塞性肺疾病全球倡议(GOLD 2017版)制订的肺功能诊断标准分为Ⅰ-Ⅳ级4组,受试前8 h内均未应用支气管舒张剂。所有患者在吸入沙丁胺醇400μg后接受常规肺功能和气道阻力测试。同期选择42例成年健康体检者作为对照组。结果Ⅱ级以上COPD患者的第1秒用力呼气容积和呼出50%肺活量时流量均显著低于健康成年人和Ⅰ级COPD患者,总气道阻力、有效气道阻力、吸气阻力和呼气阻力则呈进行性增高。Ⅲ-Ⅳ级COPD患者的深吸气量占预计值百分比(IC%pred)<80%,同时改良英国医学研究委员会呼吸困难量表评分超过2分;7例Ⅲ级(13.2%)和14例Ⅳ级COPD患者(33.3%)的吸气分数(IC/TLC)≤25%,而仅有1例Ⅱ级COPD患者的IC/TLC≤25%(1.9%)。结论稳定期中重度COPD患者呼出气流受限趋于加重,Raw各项参数中呼气阻力增高尤为显著。Ⅲ-Ⅳ级COPD患者更易出现运动相关呼吸困难症状,且IC/TLC≤25%。     

Effect of acute intermittent hypoxia treatment on ventilatory load compensation and magnitude estimation of inspiratory resistive loads in an individual with chronic incomplete cervical spinal cord injury

Context

Spinal cord injury (SCI) causes disruption of the efferent input to and afferent input from respiratory muscles, which impairs respiratory motor and sensory functions, respectively. This disturbs the injured individual''s ability to respond to ventilatory loads and may alter the respiratory perceptual sensitivity of applied loads. Acute intermittent hypoxia with elevated CO₂ (AIH treatment) has been shown to induce ventilatory long-term facilitation in individuals with chronic SCI. This study evaluated the effect of ten days of AIH treatment on ventilatory load compensation and respiratory perceptual sensitivity to inspiratory resistive loads (IRL), in an individual with chronic, incomplete cervical SCI.

Methods

Case report and literature review.

Findings

We report a case of a 55-year-old female with a C4 chronic, incomplete SCI (American Spinal Injury Association Impairment Scale D). The subject underwent evaluation at four time-points: Baseline, Post Sham, AIH Day 1 and AIH Day 10. Significant improvements in airflow generated in response to applied IRL were found after AIH treatment compared to Baseline. There were no significant changes in the respiratory perceptual sensitivity to applied IRL after AIH treatment.

Clinical relevance

Rehabilitative interventions after SCI demand restoration of the respiratory motor function. However, they must also ensure that the respiratory perceptual sensitivity of the injured individual does not hinder their capability to compensate to ventilatory challenges.     

Diastolic function in neonates after the arterial switch operation: effects of positive pressure ventilation and inspiratory time

Received: 27 July 1999/Final revision received: 21 January 2000/Accepted: 26 January 2000     

吸气肌训练对病态肥胖患者减肥术后肺功能、呼吸肌力量及耐力的影响

目的:观察吸气肌训练(IMT)对病态肥胖患者减肥术后肺功能、呼吸肌力量及耐力的影响。方法:采用随机数字表法将36例拟行减肥手术的病态肥胖患者分为观察组及对照组,每组18例。观察组及对照组患者均于术后第2~30天期间进行IMT训练,吸气阻力值分别设定为最大吸气压(MIP)的40%和5%水平,每天训练20 min。于手术前...