Influence of dipalmitoylphosphatidylcholine on the dissolution of Brazilian chrysotile

Our plain-English summary of Influence of dipalmitoylphosphatidylcholine on the dissolution of Brazilian chrysotile, by I.B. Valentim, M.H. Martins, I. Joekes (Colloids and Surfaces. B, Biointerfaces, 2008).

The study

• Authors: I.B. Valentim, M.H. Martins, I. Joekes
• Journal: Colloids and Surfaces. B, Biointerfaces
• Published: 2008;66(1):96-102
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

It is known that Brazilian chrysotile is rapidly removed from the lungs, but quantitative studies about the influence of lung surfactants on chrysotile dissolution have not been investigated. In this work, the chemical behavior of chrysotile and its dissolution in the presence of dipalmitoylphosphatidylcholine (DPPC) were investigated in physiological conditions. The dissolution was investigated through quantification of magnesium and silicon released by chrysotile. At 37 degrees C, the magnesium concentration is similar to control (without DPPC), which is about 2.0x10(-4)molL(-1), meaning that the dissolution process is not affected by the presence of this surfactant. The same was observed for silicon. The silicon concentration released by chrysotile is similar in all media tested. It is known that the dissolution mechanisms of brucite and tridymite layers are different. From our results, we propose that under physiological conditions, the mechanism of brucite dissolution is based on its interaction with hydrogen ions and that the mechanism of tridymite dissolution is based on a hydrolysis process.

In plain English

This was a laboratory (test-tube) study; no people or animals were involved. The authors tested whether DPPC, the main fatty substance in the fluid lining the lungs, changes how Brazilian chrysotile asbestos dissolves. Chrysotile from the Cana Brava mine, supplied by the mining company SAMA, was kept for 0.5 to 24 hours in water or in a salt buffer at pH 7.4 meant to resemble lung fluid, with and without DPPC. The authors measured the magnesium and silicon released. DPPC stuck to the fibers, more so in the buffer. In the buffer, DPPC did not change how much magnesium or silicon was released. In plain water, less magnesium was released when DPPC was present. Silicon came out more slowly than magnesium and in similar amounts in all liquids. Applying a mathematical model to the silicon results at 37 degrees C, the authors estimated a lifetime of 2.8 years for this chrysotile, which they called relatively quick. They concluded that DPPC did not affect Brazilian chrysotile dissolution under physiological conditions. They proposed different dissolution mechanisms for the magnesium and silicon layers.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory (in vitro) chemical experiment on chrysotile dissolution and surfactant adsorption
• Who was studied: No human or animal subjects. The material was Brazilian chrysotile type 5RL from the Cana Brava mine, supplied by SAMA Mineração de Amianto Ltda.
• Exposure: Washed and sonicated chrysotile placed in water or in Tris-HCl buffer (pH 7.4, with KCl), with or without DPPC vesicles (4.1 × 10−4 mol/L), for 0.5 to 24 hours. Magnesium and silicon release were measured.
• Main results:
  • DPPC adsorbed onto the chrysotile. In water, the adsorbed amount levelled off at 10, 13 and 18 mg/g at 298, 310 and 328 K. In the buffer, it levelled off at about twice those amounts.
  • The amount of DPPC adsorbed was greater when pH and ionic strength were controlled (buffer).
  • At 37 degrees C, magnesium released with DPPC was similar to the DPPC-free control, about 2.0 × 10−4 mol/L.
  • In plain water (no pH control), magnesium released with DPPC present was lower than in the DPPC-free control.
  • Silicon release was similar in all media tested.
  • Magnesium was released faster than silicon in all media.
  • Using the shrinking core model on the silicon data at 37 degrees C, the estimated lifetime of the Brazilian chrysotile was 2.8 years. The authors described this as relatively quick dissolution under physiological conditions.
• The authors' conclusion: The authors concluded that the presence of DPPC did not affect the dissolution of Brazilian chrysotile under physiological conditions. They proposed that the brucite (magnesium) layer dissolves through interaction with hydrogen ions and the tridymite (silica) layer through hydrolysis.

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Cana Brava mine, Uruaçu, Goiás

All asbestos mines

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Chrysotile, Brucite.

Related studies

• The biopersistence of brazilian chrysotile asbestos following inhalation — D.M. Bernstein, R. Rogers, et al. (2004)
• The toxicological response of Brazilian chrysotile asbestos: a multidose subchronic 90-day inhalation toxicology study with 92-day recovery to assess cellular and pathological response — D.M. Bernstein, R. Rogers, et al. (2006)
• Biodurability and release of metals during the dissolution of chrysotile, crocidolite and fibrous erionite — A.F. Gualtieri, G. Lusvardi, et al. (2019)
• Chrysotile dissolution in the rhizosphere of the nickel hyperaccumulator Leptoplax emarginata — V. Chardot-Jacques, C. Calvaruso, et al. (2013)
• Asbestos health hazard: a spectroscopic study of synthetic geoinspired Fe-doped chrysotile — E. Foresti, E. Fornero, et al. (2009)
• Weathering of chrysotile asbestos by the serpentine rock-inhabiting fungus Verticillium leptobactrum — S. Daghino, F. Turci, et al. (2009)

Browse return to medical research.