Jul 1, 1968

Rate of disappearance of labeled carbon dioxide from the lungs of humans during breath holding: a method for studying the dynamics of pulmonary CO2 exchange

The Journal of Clinical Investigation
R W HydeR E Forster


The dynamics of CO(2) exchange in the lungs of man was studied by observing the rate of disappearance of a stable isotope of CO(2) ((13)CO(2)) from the alveolar gas during breath holding. Over 50% of the inspired isotope disappeared within the first 3 sec followed by a moderately rapid logarithmic decline in which one-half of the remaining (13)CO(2) disappeared every 10 sec. The large initial disappearance of (13)CO(2) indicated that alveolar (13)CO(2) equilibrated in less than 3 sec with the CO(2) stored in the pulmonary tissues and capillary blood. The volume of CO(2) in the pulmonary tissues calculated from this initial disappearance was 200 ml or 0.33 ml of CO(2) per milliliter of pulmonary tissue volume. The alveolar to end-capillary gradient for (13)CO(2) was calculated by comparing the simultaneous disappearance rates of (13)CO(2) and acetylene. At rest and during exercise this gradient for (13)CO(2) was either very small or not discernible, and diffusing capacity for CO(2) (D(LCO2)) exceeded 200 ml/(min x mm Hg). After the administration of a carbonic anhydrase inhibitor the rate of disappearance of (13)CO(2) decreased markedly. D(LCO2) fell to 42 ml/(min x mm Hg) and at least 70% of the exchange of (13)CO(2) with the C...Continue Reading

  • References10
  • Citations12


Mentioned in this Paper

Pulmonary Alveolar Structure
Breath Holding
Carbonic Acid Ions
Capillary Blood
Entire Capillary Blood Vessel (Organ)
Bicarbonate Measurement
Capillary Vessel

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Coronavirus Protein Structures

Deciphering and comparing the proteins of different coronaviruses forms a basis for understanding SARS-CoV-2 evolution and virus-receptor interactions. This feed follows studies analyzing the structures of coronavirus proteins, thereby revealing potential drug target sites.

DDX3X Syndrome

DDX3X syndrome is caused by a spontaneous mutation at conception that primarily affects girls due to its location on the X-chromosome. DDX3X syndrome has been linked to intellectual disabilities, seizures, autism, low muscle tone, brain abnormalities, and slower physical developments. Here is the latest research.

ALS: Stress Granules

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by cytoplasmic protein aggregates within motor neurons. TDP-43 is an ALS-linked protein that is known to regulate splicing and storage of specific mRNAs into stress granules, which have been implicated in formation of ALS protein aggregates. Here is the latest research.

Fusion Oncoproteins in Childhood Cancers

This feed explores the function of fusion oncoproteins in specific childhood cancers, including those from racial/ethnic minority and underserved groups, and to provide preclinical assessment of potential therapeutics and how fusion oncoproteins influence gene expression to perturb normal cellular programs to block lineage differentiation and development

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Regulation of Vocal-Motor Plasticity

Dopaminergic projections to the basal ganglia and nucleus accumbens shape the learning and plasticity of motivated behaviors across species including the regulation of vocal-motor plasticity and performance in songbirds. Discover the latest research on the regulation of vocal-motor plasticity here.

Mitotic-exit networks with cytokinesis

Cytokinesis is the highly regulated process that physically separates daughter and mother cells in late mitosis. The mitotic-exit network (MEN), the signalling pathway that drives mitotic exit, directly regulates cytokinesis. Discover the latest research on mitotic-exit networks with cytokinesis here.

DNA Replication Origin

DNA replication is initiated as specific gene sequences, called origins, that function to start DNA replication. Pre-replication complexes are assembled at these origins during the G1 phase of the cell cycle. These sequences allow for targeted activation or deactivation of replication. Discover the latest research on DNA replication origins here.