Abstract:
:The aim of the study was to determine whether closing pressures or vascular distensibility can be used to describe liver venous hemodynamics when right atrial pressure is raised. The study was performed using a vascularly isolated pig liver preparation that allowed the independent control of portal vein and hepatic artery inflows and of outflow pressure (Pout). Pressure-flow (P-Q) relationships of both liver vessels were generated at multiple levels of Pout. At Pout of 0 mm Hg, the portal vein P-Q relationship was linear, with a convexity toward the pressure axis at low flows (5 to 10 ml/min/kg). The zero flow pressure was 1.5 +/- 0.2 mm Hg, greater than Pout (p < 0.05). On raising Pout from 0 to 15 mm Hg, the shape of the portal vein P-Q relationships became progressively more linear, with a decrease in slope; no difference between zero flow pressure and Pout was observed. At Pout of 0 mm Hg, the hepatic artery presented a zero flow pressure > Pout. Raising Pout from 0 to 15 and 30 mm Hg resulted in a zero flow pressure always > Pout (p < 0.05). The behavior of the liver vein system is characterized by a zero flow pressure mimicking a classic vascular waterfall and by distensibility, once the waterfall is exceeded. Both factors act to minimize the reduction in venous return with an increased central venous pressure. Flow through the hepatic artery is affected by an increase in backpressure occurring upstream from the sinusoids, reducing arterial inflow for a constant perfusion pressure.
journal_name
Am J Respir Crit Care Medauthors
Brienza N,Ayuse T,O'Donnell CP,Permutt S,Robotham JLdoi
10.1164/ajrccm.152.2.7633700subject
Has Abstractpub_date
1995-08-01 00:00:00pages
511-8issue
2eissn
1073-449Xissn
1535-4970journal_volume
152pub_type
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200412-1620OC
更新日期:2005-09-15 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.150.2.8049840
更新日期:1994-08-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
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doi:10.1164/ajrccm.162.4.2003064
更新日期:2000-10-01 00:00:00
abstract::A higher exposure to endotoxin was hypothesized to contribute to lower prevalence of allergic sensitization and hay fever in children growing up on a farm. We studied the association between house dust endotoxin and allergic sensitization. We randomly selected 740 children, aged between 5 and 10 years, from a group of...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
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更新日期:2002-10-01 00:00:00
abstract::Methodologies used to assess airway responsiveness (AR) in children administer the same dosage schedule to all children despite the great range in the size of subjects. The aim of this study was to examine the hypothesis that the level of AR is size dependent within same-age cohorts and between different ages. Among a...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.152.2.7633710
更新日期:1995-08-01 00:00:00
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doi:10.1164/ajrccm.165.4.2004005
更新日期:2002-02-15 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.161.2.9810091
更新日期:2000-02-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.164.1.2007010
更新日期:2001-07-01 00:00:00
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更新日期:2019-06-15 00:00:00
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更新日期:2013-10-15 00:00:00
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pub_type: 杂志文章
doi:10.1164/rccm.201507-1491OC
更新日期:2016-08-15 00:00:00
abstract:RATIONALE:MicroRNAs (miRNAs) destabilize mRNA transcripts and inhibit protein translation. miR-145 is of particular interest in cystic fibrosis (CF) as it has a direct binding site in the 3'-untranslated region of CFTR (cystic fibrosis transmembrane conductance regulator) and is upregulated by the CF genetic modifier T...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.201704-0732OC
更新日期:2018-03-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,实务指引
doi:10.1164/rccm.201908-1581ST
更新日期:2019-10-01 00:00:00
abstract::Previous studies suggest that lung function tests using monodisperse aerosols can help to identify early stages of lung diseases. We investigated intrapulmonary particle loss and aerosol bolus dispersion-a marker of convective gas transport-in 32 women with asymptomatic nonspecific bronchial hyperresponsiveness (BHR) ...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.159.3.9805036
更新日期:1999-03-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.200909-1398OC
更新日期:2010-05-15 00:00:00
abstract::Bradykinin (BK) induces bronchoconstriction in asthmatic but not in normal individuals. Studies in vivo in the human suggest that BK causes cholinergic nerve activation, release of prostanoids, and local axon reflexes with release of tachykinins in the airways. To determine the mechanisms of BK-induced airway narrowin...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.150.4.7921430
更新日期:1994-10-01 00:00:00
abstract::Rationale: Sleep-disordered breathing (SDB) is associated with increased vascular resistance in children and adults. Persistent increased vascular resistance damages vascular endothelial cells-a marker of which is increased platelet activation.Objectives: This study compared whole-blood impedance platelet aggregation ...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/rccm.201911-2229OC
更新日期:2020-12-01 00:00:00
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journal_title:American journal of respiratory and critical care medicine
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doi:10.1164/rccm.2111028
更新日期:2002-10-01 00:00:00
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pub_type: 杂志文章,随机对照试验
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更新日期:2015-10-01 00:00:00
abstract::To better understand strategies for recruiting and maintaining lung volume in acute lung injury, we examined relationships between steady-state lung volume and cumulative cyclic recruitment/derecruitment volume history and the quasi-static pressure-volume curve, in an animal saline lavage lung injury model. Small-volu...
journal_title:American journal of respiratory and critical care medicine
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doi:10.1164/rccm.200305-614OC
更新日期:2004-04-15 00:00:00
abstract::Large pleural effusions are typically associated with dyspnea and potential respiratory compromise. Experimental evidence suggests that with large effusions, increased intrapleural pressure may be transmitted to the pericardial space, resulting in impaired cardiac filling and reduced stroke volume. We report two cases...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm/151.3_Pt_1.904
更新日期:1995-03-01 00:00:00
abstract::Disordered breathing during sleep is associated with acute, unfavorable effects on cardiovascular physiology, but few studies have examined its postulated association with cardiovascular disease (CVD). We examined the cross-sectional association between sleep- disordered breathing and self-reported CVD in 6,424 free-l...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,多中心研究
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更新日期:2001-01-01 00:00:00
abstract::Ventilation style influences lung injury and the amount of large-aggregate biophysically active surfactant in adult lungs. We asked how positive end-expiratory pressures (PEEP) would influence clinical responses and surfactant pools in surfactant-treated preterm lambs ventilated for 7 h with tidal volumes (VT) of 10 m...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
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更新日期:1999-08-01 00:00:00
abstract::Viral respiratory tract infections are associated with an acute increase in airway responsiveness in normal subjects and patients with asthma. Airway responsiveness is also increased at least transiently in animals during acute viral infections. In this article, we discuss possible mechanisms whereby viral infections ...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,评审
doi:10.1164/ajrccm.151.5.7735630
更新日期:1995-05-01 00:00:00
abstract::Many patients who develop incapacitating illness have not expressed clear treatment preferences. Therefore, surrogate decision makers are asked to make judgments about what treatment pathway is most consistent with the patient's values. Surrogates often struggle with such decisions. The difficulty arises because answe...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,评审
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更新日期:2012-09-15 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
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doi:10.1164/rccm.200606-735OC
更新日期:2007-04-01 00:00:00
abstract::We examined the influence of gender on the polysomnographic features of obstructive sleep apnea (OSA) in a retrospective study of 830 patients with OSA diagnosed by overnight polysomnography (PSG). The severity of OSA was determined from the apnea- hypopnea index (AHI) for total sleep time (AHI(TST)), and was classifi...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.161.5.9904121
更新日期:2000-05-01 00:00:00
abstract::Wheezing in childhood is not a single disorder and different wheezing-associated respiratory illnesses have been recently described. We investigated the association between wheezing conditions and familial, pre-, peri-, and postnatal risk factors. We studied 16,333 children, 6 to 7 yr old, enrolled in a population-bas...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章,多中心研究
doi:10.1164/ajrccm.160.5.9811002
更新日期:1999-11-01 00:00:00
abstract::Studies have shown evidence of significant parent-offspring and sibling correlation in FEV1, but familial aggregation of decline of FEV1 over time has not been reported. Our study population comprised 392 families enrolled in the Tucson Epidemiological Study of Airway Obstructive Diseases. Subjects were older than 18 ...
journal_title:American journal of respiratory and critical care medicine
pub_type: 杂志文章
doi:10.1164/ajrccm.164.7.2010051
更新日期:2001-10-01 00:00:00
abstract:RATIONALE:Defective efferocytosis (phagocytic clearance of apoptotic cells) in the airway may perpetuate inflammation via secondary necrosis in chronic obstructive pulmonary disease (COPD). We have previously reported that low-dose azithromycin improved alveolar macrophage (AM) phagocytic function in vitro. OBJECTIVES...
journal_title:American journal of respiratory and critical care medicine
pub_type: 临床试验,杂志文章
doi:10.1164/rccm.200711-1666OC
更新日期:2008-07-15 00:00:00