Perfluorocarbure

Les perfluorocarbures (PFC) ou hydrocarbures perfluorés sont des composés halogénés gazeux de la famille des fluorocarbures (FC). Ces gaz fluorés sont composés exclusivement d'atomes de carbone et de fluor (contrairement aux hydrofluorocarbures (HFC), ils sont totalement substitués). Ces composés synthétiques ont la particularité de dissoudre de grandes quantités de gaz, comme le dioxygène (), le dioxyde de carbone (), le diazote (N2), etc. Ils peuvent dissoudre jusqu'aux deux tiers de leur volume de gaz. Ils ne sont pas réputés dangereux pour la couche d'ozone, mais les PFC sont des gaz à effet de serre (GES). Bien qu'émis en faible quantité dans l’air, ils participent au dérèglement climatique, en raison de leur potentiel élevé en matière de réchauffement planétaire (PRP - 100 ans) correspondant en moyenne à celui du dioxyde de carbone (), allant d'un facteur de () à un facteur de (). Ces grandes valeurs de potentiel de réchauffement planétaire sont notamment dues à leur grand

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Selective in vivo visualization of immune-cell infiltration in a mouse model of autoimmune myocarditis by fluorine-19 cardiac magnetic resonance

Ruud van Heeswijk

Background- The goal of this study was to characterize the performance of fluorine-19 ((19)F) cardiac magnetic resonance (CMR) for the specific detection of inflammatory cells in a mouse model of myocarditis. Intravenously administered perfluorocarbons are taken up by infiltrating inflammatory cells and can be detected by (19)F-CMR. (19)F-labeled cells should, therefore, generate an exclusive signal at the inflamed regions within the myocardium. Methods and Results- Experimental autoimmune myocarditis was induced in BALB/c mice. After intravenous injection of 2×200 µL of a perfluorocarbon on day 19 and 20 (n=9) after immunization, in vivo (19)F-CMR was performed at the peak of myocardial inflammation (day 21). In 5 additional animals, perfluorocarbon combined with FITC (fluorescein isothiocyanate) was administered for postmortem immunofluorescence and flow-cytometry analyses. Control experiments were performed in 9 animals. In vivo (19)F-CMR detected myocardial inflammation in all experimental autoimmune myocarditis-positive animals. Its resolution was sufficient to identify even small inflammatory foci, that is, at the surface of the right ventricle. Postmortem immunohistochemistry and flow cytometry confirmed the presence of perfluorocarbon in macrophages, dendritic cells, and granulocytes, but not in lymphocytes. The myocardial volume of elevated (19)F signal (rs=0.96; P

2013

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Influence of intravenous perfluorocarbon administration on the dynamic behavior of lung surfactant

Melody Swartz

Intravenous administration of perfluorocarbon (PFC) compounds can lead to pulmonary hyperinflation and respiratory distress in some mammals. This study was designed to quantify the effects of two PFC emulsions on the dynamic behavior of lung surfactant and to demonstrate that PFC is retained in the liquid lining the lung. New Zealand White rabbits received isotonic saline (3 ml/kg), Fluosol (15 ml/kg) or Oxygent (90% perfluorooctyl-bromide emulsion, 3 ml/kg). After seven days we euthanized the animals and lavaged the lungs. Surface tension-surface area relationships (sigma-A loops) were measured with the lavage fluid placed in a Wilhelmy plate-oscillating bellows apparatus. Loop hysteresis area after Fluosol administration was 334 +/- 92 dyne-cm, significantly greater than after saline (203 +/- 36 dyne-cm) but not Oxygent (274 +/- 66 dyne-cm). Loop hysteresis slope was higher with Oxygent (0.8 +/- 0.4 dyne/cm3) than after saline (0.6 +/- 0.3 dyne/cm3) or Fluosol (0.5 +/- 0.1 dyne/cm3). 282 MHz 19F NMR spectral analysis demonstrates that both PFCs tested appear only in the extracellular fraction of the lavage fluid. These results show that pulmonary elimination of intravascular PFC leads to PFC presence in the liquid lining the airways where it alters surfactant dynamic mechanical behavior.

1998

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Perfluorocarbon induced alterations in pulmonary mechanics

Melody Swartz

Perfluorocarbon (PFC) compounds induce pulmonary hyperinflation and respiratory distress in some animals following intravenous administration. This study was designed to quantify the effects of two PFC emulsions on lung volumes and compliance and to identify the mechanism of pulmonary hyperinflation. New Zealand White rabbits received isotonic saline (3 ml/kg), Fluosol (15 ml/kg) or Oxygent (90% perfluorooctyl-bromide emulsion, 3 ml/kg). After seven days we measured functional residual capacity, vital capacity, lung compliance and thoracic gas volume. Gross and microscopic histologic examination of the lungs was performed. Functional residual capacity after Fluosol administration was 16.0 +/- 4.0 ml/kg, significantly greater than after saline (3.4 +/- 1.0 ml/kg) or Oxygent (4.0 +/- 1.4 ml/kg). Vital capacity was lower with Fluosol (30 +/- 5.0 ml/kg) than after saline (37 +/- 3.0 ml/kg) or Oxygent (37 +/- 2.0 ml/kg). Thoracic gas volume increased from 9 +/- 1.0 ml/kg (saline) to 16 +/- 13 ml/kg (Oxygent) and 33 +/- 7.0 ml/kg (Fluosol). Lung compliance was the same after saline (1.6 +/- 0.5 ml.cm H2O-1.kg-1) and Oxygent (1.5 +/- 0.3 ml.cm H2O-1.kg-1) but lower after Fluosol (0.9 +/- 0.1 ml.cm H2O-1.kg-1). Gross pathology demonstrated foam exudation from airways of animals receiving PFCs and intra-alveolar foam was identified by light microscopy. These results show intra-airway foam formation causes gas trapping and shifts tidal breathing to a less compliant region of the pressure-volume curve.

1998

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Fluor

vignette|Un tube contenant du fluor dans un bain de liquide cryogénique. Le fluor est l'élément chimique de numéro atomique 9, de symbole F. C'est le premier élément du groupe des halogènes. Le corps

Polytétrafluoroéthylène

Le polytétrafluoroéthylène (sigle PTFE) est un fluoropolymère issu du tétrafluoroéthylène. Ce polymère technique a été découvert par hasard en 1938 par le chimiste Roy J. Plunkett (1910-1994) qui t

Potentiel de réchauffement global

Le potentiel de réchauffement global (PRG) est le pouvoir réchauffant d'un gaz, rapporté au pouvoir réchauffant de la même masse de dioxyde de carbone. C'est un facteur de conversion utilisé pour co

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