Abstract:
:The length of time that blood remains in the pulmonary capillary is an important variable in gas exchange. We have investigated the distribution of capillary transit times in isolated rabbit lungs perfused with a bicarbonate-free buffer. The time course of gas exchange was monitored by enclosing the lungs in a plethysmograph. A bolus of buffer containing dissolved acetylene was injected into the perfusion system. Exchange of this inert gas occurred as soon as the bolus reached the capillary bed, thereby describing the input function into the bed. A separate bolus injection of bicarbonate solution resulted in production and excretion of CO2 as long as the bolus remained in the capillary bed. The rate of CO2 production was adjusted by partial inhibition of endothelial carbonic anhydrase. The distribution of capillary transit times was computed from a model of CO2 production in the capillary bed and the observed rates and volumes of acetylene and carbon dioxide excretion. The recovered distributions indicate that there is a fairly wide distribution of capillary transit times (relative dispersion, 0.45) around the mean value of 1.71 s (+/- 0.53 [SD]). Only 10% of capillary transit times are less than one half of mean transit time. It is likely that gas exchange reaches equilibrium in the capillary bed except possibly during strenuous exercise or exposure to high altitude or in disease.
journal_name
Am J Respir Crit Care Medauthors
Klocke RA,Schünemann HJ,Grant BJdoi
10.1164/ajrccm.152.6.8520770subject
Has Abstractpub_date
1995-12-01 00:00:00pages
2014-20issue
6 Pt 1eissn
1073-449Xissn
1535-4970journal_volume
152pub_type
杂志文章abstract::Endothelins (ET-1, ET-2, ET-3) are potent bronchoconstrictors and growth-promoting mediators. They are released from various cells such as endothelial and epithelial cells. In the airways, ETs are released under basal and stimulated conditions. In patients with status asthmaticus and other pulmonary disorders, the exp...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.155.6.9196090
更新日期:1997-06-01 00:00:00
abstract:RATIONALE:Pulmonary infection in cystic fibrosis (CF) is polymicrobial and it is possible that anaerobic bacteria, not detected by routine aerobic culture methods, reside within infected anaerobic airway mucus. OBJECTIVES:To determine whether anaerobic bacteria are present in the sputum of patients with CF. METHODS:S...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,多中心研究
doi:10.1164/rccm.200708-1151OC
更新日期:2008-05-01 00:00:00
abstract::We tested the hypothesis that continuous positive airway pressure (CPAP) use and outcomes can be improved by an autotitrating CPAP device in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) who require higher CPAP (10 cm H2O or more). In this multisite randomized single-blind cross-over study, 44 patien...
journal_title:American journal of respiratory and critical care medicine
pub_type: 临床试验,杂志文章,多中心研究,随机对照试验
doi:10.1164/rccm.200201-022OC
更新日期:2003-01-01 00:00:00
abstract:RATIONALE:Recent findings have demonstrated that muscarinic M(3) receptor stimulation enhances airway smooth muscle proliferation to peptide growth factors in vitro. Because both peptide growth factor expression and acetylcholine release are known to be augmented in allergic airway inflammation, it is possible that ant...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200409-1249OC
更新日期:2005-05-15 00:00:00
abstract::The factors that lead to increased production of specific IgG subclasses are still largely unknown. Recent studies suggest that increased IgG4 responses may be related to prolonged antigen exposure. We present data showing that increased IgG4 responses are found under conditions of chronic exposure to Aspergillus fumi...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.153.6.8665060
更新日期:1996-06-01 00:00:00
abstract:RATIONALE:The relationship between clinical phenotype of childhood primary ciliary dyskinesia (PCD) and ultrastructural defects and genotype is poorly defined. OBJECTIVES:To delineate clinical features of childhood PCD and their associations with ultrastructural defects and genotype. METHODS:A total of 118 participan...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,多中心研究
doi:10.1164/rccm.201409-1672OC
更新日期:2015-02-01 00:00:00
abstract::To determine if gastric intramucosal pH changes during weaning from mechanical ventilation are related to gastric mucosal blood flow modifications, we studied 16 ventilator-supported patients with chronic obstructive pulmonary disease (COPD) who tolerated a 2-h trial of spontaneous breathing with pressure support vent...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.160.5.9901018
更新日期:1999-11-01 00:00:00
abstract::A protective role for dietary antioxidants in asthma has been proposed. However, epidemiological evidence to implicate antioxidant vitamins is weak, and data on the role of flavonoid-rich foods and antioxidant trace elements are lacking. We carried out a population-based case-control study in South London, UK, to inve...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.164.10.2104061
更新日期:2001-11-15 00:00:00
abstract::Although sleep-disordered breathing (SDB) has been shown to be very prevalent in the elderly, little has been done to examine differences between the elderly of different racial groups. It has been well documented that SDB often results in hypertension and that hypertension is more common in African-Americans than in ...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.152.6.8520760
更新日期:1995-12-01 00:00:00
abstract:RATIONALE:Daily azithromycin decreases acute exacerbations of chronic obstructive pulmonary disease (AECOPD), but long-term side effects are unknown. OBJECTIVES:To identify the types of exacerbations most likely to be reduced and clinical subgroups most likely to benefit from azithromycin, 250 mg daily, added to usual...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,随机对照试验
doi:10.1164/rccm.201402-0207OC
更新日期:2014-06-15 00:00:00
abstract::Rationale: Interstitial macrophages (IMs) and airspace macrophages (AMs) play critical roles in lung homeostasis and host defense, and are central to the pathogenesis of a number of lung diseases. However, the absolute numbers of macrophages and the precise anatomic locations they occupy in the healthy human lung have...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.201911-2105OC
更新日期:2020-05-15 00:00:00
abstract::To investigate interactions between the endothelium and leukocytes in patients with sepsis, we measured soluble adhesion molecules (sE-selectin and sICAM-1), von Willebrand factor antigen (vWf:Ag), myeloperoxidase (MPO), and lactoferrin (Lacto-f) as plasma markers of endothelial and neutrophil activation. We tested wh...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.157.3.9705034
更新日期:1998-03-01 00:00:00
abstract::The inheritance of asthma, evident from its high family concordance, is not well understood. To investigate whether asthma may be inherited through a major gene with two alleles, segregation analyses were conducted in 3,369 individuals from 906 nuclear families enrolled, without selection, in a longitudinal study of r...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.154.1.8680670
更新日期:1996-07-01 00:00:00
abstract:RATIONALE:Increasing epithelial repair and regeneration may hasten resolution of lung injury in patients with the acute respiratory distress syndrome (ARDS). In animal models of ARDS, keratinocyte growth factor (KGF) reduces injury and increases epithelial proliferation and repair. The effect of KGF in the human alveol...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,随机对照试验
doi:10.1164/rccm.201310-1892OC
更新日期:2014-06-15 00:00:00
abstract::Snoring and sleeping apnea are reportedly associated with morbidity. We used home monitoring (MESAM IV) to measure snoring and sleep apnea in 294 men aged 40 to 65 yr from the volunteer register of the Busselton (Australia) Health Survey. In this group, 81% snored for more than 10% of the night and 22% for more than h...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.151.5.7735600
更新日期:1995-05-01 00:00:00
abstract:RATIONALE:Endobronchial ultrasound (EBUS) and electromagnetic navigation bronchoscopy (ENB) have increased the diagnostic yield of bronchoscopic diagnosis of peripheral lung lesions. However, the role of combining these modalities to overcome each individual technique's limitations and, consequently, to further increas...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,随机对照试验
doi:10.1164/rccm.200612-1866OC
更新日期:2007-07-01 00:00:00
abstract:RATIONALE:Lung allografts are prone to reperfusion injury and acute rejection, which, in addition to infiltrating lymphocytes, are accompanied by neutrophil infiltration and neutrophil-associated oxidative stress. Indoleamine 2,3-dioxygenase (IDO) is a unique cytosolic enzyme that possesses T-cell-suppressive and antio...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200509-1413OC
更新日期:2006-03-01 00:00:00
abstract:RATIONALE:Mechanical ventilation is known to induce ventilator-induced diaphragm dysfunction. Patients submitted to mechanical ventilation often receive massive doses of corticosteroids that may cause further deterioration of diaphragm function. OBJECTIVES:To examine whether the combination of 24 hours of controlled m...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200702-296OC
更新日期:2008-12-15 00:00:00
abstract:RATIONALE:T-bet (TBX21 or T-box 21) is a critical regulator of T-helper 1 lineage commitment and IFN-gamma production. Knockout mice lacking T-bet develop airway hyperresponsiveness (AHR) to methacholine, peribronchial eosinophilic and lymphocytic inflammation, and increased type III collagen deposition below the bronc...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200503-505OC
更新日期:2006-01-01 00:00:00
abstract:RATIONALE:Secondhand smoke exposure (SHSe) is a significant modifiable risk for respiratory health in children. Although SHSe is declining overall, it has increased for low-income and minority populations. Implementation of effective SHSe interventions within community organizations has the potential for significant pu...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,随机对照试验
doi:10.1164/rccm.201404-0618OC
更新日期:2014-06-15 00:00:00
abstract::The influx of neutrophils into the lung is a sentinel event in LPS-induced acute lung inflammation. Previous studies have shown that systemic inhibition of p38 decreases LPS-induced neutrophil influx into the alveolar space but has no effect on pulmonary parenchymal neutrophil accumulation or on microvascular leak, in...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200406-712OC
更新日期:2005-05-01 00:00:00
abstract::Eotaxin, a selective chemoattractant for eosinophils, induces lung eosinophilia and bronchial hyperresponsiveness (BHR) when administered intratracheally to interleukin-5 (IL-5) transgenic mice. We determined whether these effects of eotaxin were mediated through the production of cysteinyl-leukotrienes. IL-5 transgen...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.160.2.9810101
更新日期:1999-08-01 00:00:00
abstract:RATIONALE:Encephalitis caused by anti-N-methyl-d-aspartate receptor (NMDAR) antibodies is the leading cause of immune-mediated encephalitis. There are limited data on intensive care unit (ICU) management of these patients. OBJECTIVES:To identify prognostic factors of good neurologic outcome in patients admitted to an ...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,多中心研究
doi:10.1164/rccm.201603-0507OC
更新日期:2017-02-15 00:00:00
abstract::Qualitatively the mechanical, structural, and biochemical properties of airway smooth muscles resemble those of all other smooth muscle. However, one important distinguishing feature of airway smooth muscle is that the major portion of isotonic shortening is completed within the first 3 s in a muscle whose contraction...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,评审
doi:10.1164/ajrccm.158.supplement_2.13tac300
更新日期:1998-11-01 00:00:00
abstract::Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension in which the vascular changes originate in the small pulmonary veins and venules. The pathogenesis is unknown and any link with primary pulmonary hypertension (PPH) has been speculative. Mutations in the bone morphogenetic protein recepto...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200208-861OC
更新日期:2003-03-15 00:00:00
abstract:RATIONALE:Acute respiratory distress syndrome is refractory to pharmacological intervention. Inappropriate activation of alveolar neutrophils is believed to underpin this disease's complex pathophysiology, yet these cells have been little studied. OBJECTIVES:To examine the functional and transcriptional profiles of pa...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.201509-1818OC
更新日期:2016-10-15 00:00:00
abstract:BACKGROUND:Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecula...
journal_title:American journal of respiratory and critical care medicine
pub_type: 指南,杂志文章
doi:10.1164/rccm.201806-1160ST
更新日期:2018-08-15 00:00:00
abstract::Asthma in adults may be associated with chronic airflow obstruction, possibly resulting from airway disease in early life and/or a greater rate of decline in lung function in adult life compared with those with asthma. Treatment and cigarette smoking may also influence the rate of decline of lung function. The aim of ...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200402-230OC
更新日期:2005-01-15 00:00:00
abstract::Preventing, treating, and promoting recovery from critical illness due to pulmonary disease are foundational goals of the critical care community and the National Heart, Lung, and Blood Institute. Decades of clinical research in acute respiratory distress syndrome, acute respiratory failure, pneumonia, and sepsis have...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.201908-1595WS
更新日期:2020-03-09 00:00:00
abstract:RATIONALE:Intensive care unit (ICU) nurses work in a demanding environment where they are repetitively exposed to traumatic situations and stressful events. The psychological effects on nurses as a result of working in the ICU are relatively unknown. OBJECTIVE:To determine whether there is an increased prevalence of p...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200606-735OC
更新日期:2007-04-01 00:00:00