Biophysical Activity of Animal-Derived Exogenous Surfactants Mixed with Rifampicin

2014 ◽  
pp. 31-39 ◽  
Author(s):  
M. Kolomaznik ◽  
A. Calkovska ◽  
E. Herting ◽  
G. Stichtenoth
Keyword(s):  
Biophysical Activity

Hydrophobic homopolymeric peptides enhance the biophysical activity of synthetic lung phospholipids

1990 ◽  
Vol 53 (2-3) ◽  
pp. 157-164 ◽  
Author(s):  
A.R. Venkitaraman ◽  
S.B. Hall ◽  
R.H. Notter
Keyword(s):  
Biophysical Activity

scholarly journals Secondary structure and biophysical activity of synthetic analogues of the pulmonary surfactant polypeptide SP-C

1995 ◽  
Vol 307 (2) ◽  
pp. 535-541 ◽  
Author(s):  
J Johansson ◽  
G Nilsson ◽  
R Strömberg ◽  
B Robertson ◽  
H Jörnvall ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Pulmonary Surfactant ◽  
Transmembrane Helix ◽  
Helical Structure ◽  
Helical Conformation ◽  
Synthetic Analogues ◽  
Charged Amino Acids ◽  
Phospholipid Micelles ◽  
Helical Content ◽  
Biophysical Activity

Native pulmonary-surfactant-associated lipopolypeptide SP-C, its chemically depalmitoylated form and several synthetic analogues lacking the palmitoylcysteine residues were analysed for secondary structure in phospholipid micelles and for biophysical activity in 1,2-dipalmitoyl-sn-glycero-3- phosphocholine/phosphatidylglycerol/palmitic acid (68:22:9, by wt.). Compared with the native molecule, with the entire poly-valyl part in a known alpha-helical conformation, depalmitoylated SP-C was found to be still mainly alpha-helical, but with an approx. 20% decrease in the helical content. A synthetic hybrid polypeptide where the entire poly-valyl alpha-helical part of native SP-C had been replaced with the amino acid sequence of a transmembrane helix of bacteriorhodopsin is also predominantly alpha-helical. In contrast, synthetic SP-C analogues lacking only the palmitoyl groups, by replacement of the palmitoylcysteine residues with cysteine, phenylalanine or serine, or lacking the positively charged amino acids by replacement with alanine, are considerably less alpha-helical than both native and depalmitoylated SP-C. The data indicate that the SP-C palmitoyl groups are important for maintenance of the alpha-helical conformation in parts of the polypeptide, and that the poly-valyl alpha-helical conformation is not fully formed in synthetic SP-C polypeptides. Furthermore, the helical structure of both native and depalmitoylated SP-C in dodecylphosphocholine micelles is very resistant to thermal denaturation, exhibiting ordered structure at 90 degrees C. The alpha-helical content grossly parallels the peptide-induced acceleration of the spreading of phospholipids at an air/water interface and the increase of surface pressure. The data suggest that the alpha-helical conformation itself, rather than just the covalent structure, is of prime importance for the biological function of synthetic pulmonary-surfactant peptides.

scholarly journals Molecular and biophysical mechanisms behind the enhancement of lung surfactant function during controlled therapeutic hypothermia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Autilio ◽  
M. Echaide ◽  
A. Cruz ◽  
C. Mouton ◽  
A. Hidalgo ◽  
...  
Keyword(s):  
Therapeutic Hypothermia ◽  
Molecular Mechanisms ◽  
Lung Surfactant ◽  
Interfacial Structure ◽  
Surfactant Activity ◽  
Improved Performance ◽  
Biophysical Activity ◽  
Respiratory Outcomes

AbstractTherapeutic hypothermia (TH) enhances pulmonary surfactant performance in vivo by molecular mechanisms still unknown. Here, the interfacial structure and the composition of lung surfactant films have been analysed in vitro under TH as well as the molecular basis of its improved performance both under physiological and inhibitory conditions. The biophysical activity of a purified porcine surfactant was tested under slow and breathing-like dynamics by constrained drop surfactometry (CDS) and in the captive bubble surfactometer (CBS) at both 33 and 37 °C. Additionally, the temperature-dependent surfactant activity was also analysed upon inhibition by plasma and subsequent restoration by further surfactant supplementation. Interfacial performance was correlated with lateral structure and lipid composition of films made of native surfactant. Lipid/protein mixtures designed as models to mimic different surfactant contexts were also studied. The capability of surfactant to drastically reduce surface tension was enhanced at 33 °C. Larger DPPC-enriched domains and lower percentages of less active lipids were detected in surfactant films exposed to TH-like conditions. Surfactant resistance to plasma inhibition was boosted and restoration therapies were more effective at 33 °C. This may explain the improved respiratory outcomes observed in cooled patients with acute respiratory distress syndrome and opens new opportunities in the treatment of acute lung injury.

Two Hydrophobic Protein Fractions of Ovine Pulmonary Surfactant: Isolation, Characterization, and Biophysical Activity

2001 ◽  
Vol 23 (2) ◽  
pp. 319-327 ◽  
Author(s):  
Harald Bünger ◽  
Ralph-Peter Krüger ◽  
Sylvia Pietschmann ◽  
Nadeshda Wüstneck ◽  
Lutz Kaufner ◽  
...  
Keyword(s):  
Pulmonary Surfactant ◽  
Protein Fractions ◽  
Hydrophobic Protein ◽  
Biophysical Activity

Recovery of the ovine fetus from sustained hypoxia: Effects on endocrine, cardiovascular, and biophysical activity

1994 ◽  
Vol 170 (5) ◽  
pp. 1433-1441 ◽  
Author(s):  
Yoshio Matsuda ◽  
John Patrick ◽  
Lesley Carmichael ◽  
Laurence Fraher ◽  
Bryan Richardson
Keyword(s):  
Ovine Fetus ◽  
Biophysical Activity ◽  
Sustained Hypoxia

Inhibition of pulmonary surfactant function by phospholipases

1991 ◽  
Vol 71 (1) ◽  
pp. 317-321 ◽  
Author(s):  
B. A. Holm ◽  
L. Keicher ◽  
M. Y. Liu ◽  
J. Sokolowski ◽  
G. Enhorning
Keyword(s):  
Surface Tension ◽  
Lung Injury ◽  
Pulmonary Surfactant ◽  
Detrimental Effect ◽  
Surface Film ◽  
Intratracheal Administration ◽  
Low Concentrations ◽  
Surfactant Activity ◽  
Inhibitory Agents ◽  
Biophysical Activity

Previous studies have shown that respiratory failure associated with disorders such as acute pancreatitis correlates well with increased levels of phospholipase A2 (PLA2) in lung lavages and that intratracheal administration of PLA2 generates an acute lung injury. In addition, bacteria such as Pseudomonas have been shown to secrete phospholipase C (PLC). We studied the effects of these phospholipases on pulmonary surfactant activity using a pulsating bubble surfactometer. Concentrations greater than or equal to 0.1 unit/ml PLA2 destroyed surfactant biophysical activity, increasing surface tension at minimum bubble size from less than 1 to 15 mN/m. This surfactant inactivation was predominantly related to the effect of lysophosphatidylcholine on the surface film, although the fatty acids released with higher PLA2 concentrations also had a detrimental effect on surfactant function. Similarly, as little as 0.1 unit PLC increased the surface tension at minimal size of an oscillating bubble from less than 1 to 15 mN/m, an effect that could be mimicked by the addition of dipalmitin to surfactant in the absence of PLC. Moreover, lower, noninhibitory concentrations (0.01 unit/ml) of PLA2 and PLC increased the sensitivity of surfactant to other inhibitory agents, such as albumin. Thus, relatively low concentrations of PLC and PLA2 can cause severe breakdown of surfactant function and may contribute significantly to some forms of lung injury.

Two hydrophobic low-molecular-mass protein fractions of pulmonary surfactant. Characterization and biophysical activity

1987 ◽  
Vol 168 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Tore CURSTEDT ◽  
Hans JORNVALL ◽  
Bengt ROBERTSON ◽  
Tomas BERGMAN ◽  
Per BERGGREN
Keyword(s):  
Molecular Mass ◽  
Pulmonary Surfactant ◽  
Protein Fractions ◽  
Biophysical Activity

Alteration of biophysical activity of pulmonary surfactant by aluminosilicate nanoparticles

2013 ◽  
Vol 25 (2) ◽  
pp. 77-83 ◽  
Author(s):  
Dorota Kondej ◽  
Tomasz R. Sosnowski
Keyword(s):  
Pulmonary Surfactant ◽  
Biophysical Activity

Biophysical Activity of Impaired Lung Surfactant upon Exposure to Polymer Nanoparticles

Langmuir ◽  
2016 ◽  
Vol 32 (40) ◽  
pp. 10422-10429 ◽  
Author(s):  
Moritz Beck-Broichsitter
Keyword(s):  
Lung Surfactant ◽  
Polymer Nanoparticles ◽  
Biophysical Activity
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