A finite element model of the dog lung, heart and abdomen, consisting of three solid linearly elastic bodies, was developed to study the effects of gravity on the vertical stress distribution and ...lung volume in different body positions at functional residual capacity (FRC). The geometry of the lung was obtained from an isolated dried dog lung after inflation to total lung capacity (TLC). The compliance of the rib cage, diaphragm and the abdomen was simulated by spring elements located on their surfaces. In the prone position, gravitational forces acting only on the lung contributed to the vertical gradient (0.19 cmH
2O/cm) in transpulmonary pressure (Ptp). This result was independent of chest wall compliance. In the supine position, the addition of the heart and abdomen with a compliant diaphragm and abdominal walls increased the vertical Ptp gradient to 0.53 cmH
2O/cm. In the head-up (upright) position, both heart and abdominal weight contributed to the vertical gradient (0.47 cmH
2O/cm). Diaphragmatic compliance was of less importance to the vertical gradient in the head-up and head-down positions in the absence of the abdomen. The smallest vertical gradient (0.11 cmH
2O/cm) was obtained in the head-down position with abdominal weight reducing the gradient caused by lung weight. Lung volume at FRC was virtually unaffected by gravity in the prone body position, was reduced by gravity in the supine and head-down positions but increased in the head-up position. The effects of a compliant diaphragm and abdominal weight are important contributors to the distribution of stress and volume in the intact lung.
Messenger RNA isolated from chicken pituitaries was used to construct a chicken pituitary cDNA library. A chicken growth hormone cDNA clone was isolated using 32P-labeled mammalian growth hormone ...cDNA probes. The amino acid sequence (derived from the DNA sequence) of the mature form of chicken growth hormone shows 77% homology with that of bovine growth hormone. The chicken growth hormone cDNA clone was used to generate a vector capable of producing chicken growth hormone in Escherichia coli. The recombinant E. coli-derived chicken growth hormone was similar to pituitary chicken growth hormone in several biochemical and immunological properties. The recombinant-derived hormone has been used to establish a sensitive radioimmunoassay for growth hormone determinations made from chicken sera. The chicken growth hormone gene has also been introduced into a retroviral vector capable of establishing productive infections of chicken cells both in in vitro and in vivo. The resulting infections are accompanied by the production of radioimmunoassay-detectable growth hormone. The concentrations of growth hormone in sera of Leghorn chickens infected with the recombinant retrovirus are three- to tenfold higher than in control animals.
Sugar cane cropping for biofuel production reduces water discharge from a northern Indian basin and threatens downstream communities. Regulators want to partition blame between climate change—induced ...declines in mountain snowpack and excessive evaporation from poorly managed fields. In the same basin, a tiger is found shot. Is it the nuisance animal that has been tormenting local communities, or is it a different animal poached from the upland forests?