Influence of crystallization habit of minerals on in vitro cytotoxicity

Our plain-English summary of Influence of crystallization habit of minerals on in vitro cytotoxicity, by L.D. Palekar, C.M. Spooner, D.L. Coffin (Annals of the New York Academy of Sciences, 1979).

The study

• Authors: L.D. Palekar, C.M. Spooner, D.L. Coffin
• Journal: Annals of the New York Academy of Sciences
• Published: 1979;330:673-86
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy.

Abstract

Four samples of cummingtonite-grunerite series in various crystallization habits were tested in vitro. The cytotoxicity to Chinese hamster ovary cells and hemolysis to sheep erythrocytes were inversely proportional to the structural faults and surface defects of the minerals. At a comparable surface area, asbestiform grunerite (UICC amosite), semi-asbestiform cummingtonite, acicular cummingtonite, and acicular grunerite were found to be cytotoxic and hemolytic in a decreasing order. The influence of particle size on hemolysis and cytotoxicity was observed with acicular grunerite. Although samples of relatively large particle size were found to be inert, samples of smaller particle size were cytotoxic as well as hemolytic. No apparent relationship between surface charge and hemolysis as well as cytotoxicity was observed.

In plain English

This laboratory study compared four cummingtonite-grunerite minerals that differ in crystal form. They were asbestiform grunerite (the UICC amosite standard from South Africa), semiasbestiform cummingtonite and acicular (needle-like) cummingtonite from the Homestake Mine in South Dakota, and acicular grunerite from Labrador, Canada. The authors measured how much each sample broke open sheep red blood cells (hemolysis) and how much it cut the number of Chinese hamster ovary cell colonies versus untreated cultures. Tested at 20 mg/ml and comparable surface areas, amosite caused 53.3 percent hemolysis and acicular grunerite caused none. The two cummingtonites caused 32.48 and 29.57 percent, which the authors described as no difference. At 0.05 mg/ml, amosite left under 25 percent of colonies surviving. The coarsest acicular grunerite sample was nontoxic even at 0.50 mg/ml. Ground finer, acicular grunerite became hemolytic and cytotoxic. No link with surface charge was seen. The authors concluded that crystallization habit "plays an important role" in these effects. They also wrote that nonasbestiform minerals could possibly be hazardous at higher doses and surface areas. They noted that surface areas of the finer samples were not measured.

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) experiment comparing mineral samples on red blood cells and cultured cells
• Who was studied: No people or animals were studied. The authors tested sheep red blood cells and Chinese hamster ovary (CHO) cells exposed to four mineral samples: UICC amosite (South Africa), acicular grunerite (Smallwood Mine, Wabush, Labrador, Canada), and semiasbestiform and acicular cummingtonite (Homestake Mine, South Dakota). The work was done under contract for the U.S. Environmental Protection Agency.
• Exposure: Four cummingtonite-grunerite minerals in different crystal habits: asbestiform grunerite (UICC amosite), semiasbestiform cummingtonite, acicular cummingtonite and acicular grunerite. Samples were ground to various particle sizes, with surface areas from 0.82 to 4.13 m2/g where measured. Hemolysis results in Table 2 were obtained at 20 mg/ml. Cytotoxicity doses ranged from 0.05 to 0.50 mg/ml.
• Main results:
  • Table 2 gives hemolysis results at a test concentration of 20 mg/ml.
  • Hemolysis: asbestiform grunerite (UICC amosite) with a surface area of 4.13 m2/g caused 53.3 percent hemolysis.
  • Hemolysis: acicular grunerite with a surface area of 2.82 m2/g caused no hemolysis.
  • Hemolysis: semiasbestiform cummingtonite (3.88 m2/g) caused 32.48 percent and acicular cummingtonite (3.76 m2/g) caused 29.57 percent. The authors reported no difference between these two samples.
  • Hemolysis at lower surface area: semiasbestiform cummingtonite (1.21 m2/g) caused 32.2 percent, while acicular cummingtonite (0.82 m2/g) caused 18.94 percent.
  • Hemolysis by particle size: acicular grunerite ground further caused 10 percent hemolysis, and increasingly finer samples caused 15.83, 32.48 and 40 percent. Surface areas were not measured for these finer samples.
  • CHO cells: colony survival was measured as a percent of untreated controls.
  • CHO cells: with amosite (4.13 m2/g), less than 25 percent of clones survived at 0.05 mg/ml. Survival was 5 percent at 0.1 mg/ml and 1 percent at 0.2 mg/ml.
  • CHO cells: acicular grunerite of 2.82 m2/g (Sample A, the least ground) was nontoxic even at 0.50 mg/ml. The further-ground Sample B was also nontoxic at 0.50 mg/ml.
  • CHO cells: with the finer acicular grunerite Sample C, survival was 75 percent at 0.40 mg/ml and 45 percent at 0.50 mg/ml.
  • CHO cells: with the finest acicular grunerite (Sample D), clone survival was 75 percent at 0.20 mg/ml, 55 percent at 0.30, 40 percent at 0.40 and 35 percent at 0.50 mg/ml.
  • CHO cells: with semiasbestiform cummingtonite (3.88 m2/g), 85 and 70 percent of clones survived at 0.05 and 0.10 mg/ml. Acicular cummingtonite (3.76 m2/g) showed no toxicity at these doses. At higher doses the authors saw no significant difference between the two.
  • CHO cells: acicular cummingtonite of 0.82 m2/g was nontoxic even at 0.5 mg/ml.
  • No relationship was seen between surface charge and either hemolysis or cytotoxicity. Amosite and acicular grunerite had similar surface charges (-26.9 and -26.2 mV) but very different toxicity.
• The authors' conclusion: The authors concluded that crystallization habit plays an important role in hemolysis and cytotoxicity. They added that semiasbestiform and acicular minerals should not be ignored. They also wrote that nonasbestiform minerals could possibly be hazardous to human health at higher doses and surface areas.
• Limitations the authors state:
  • Surface areas of the finer acicular grunerite samples were not available. The authors stated that no conclusive correlation could therefore be made between surface area and biological activity.
  • The particles' surface charge after contact with the red blood cells and CHO cells was not calculated. The authors said more work is needed on the role of surface charge.
  • Flexible, more asbestos-like crystals were removed from the acicular cummingtonite sample by eye, and some were probably missed.
  • There is no quantitative way to express the degree of asbestiform development, so the 'semiasbestiform' label is descriptive.

Topics

Medical terms in this study, explained in our Lexicon: Habit, Cummingtonite-Grunerite, Asbestiform, Grunerite, UICC, Amosite, Acicular.

Related studies

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• Effect of mineral dusts on metabolic cooperation between Chinese hamster V79 cells in vitro — M. Chamberlain (1983)
• Cytotoxicity of respirable dusts from industrial minerals: comparison of two naturally occurring and two man-made silicates — D. Nadeau, L. Fouquette-Couture, et al. (1987)
• Some observations on the in vitro cytotoxicity of chrysotile prepared by the wet dispersion process — I.P. Gormley, R.E. Bolton, et al. (1983)
• Binding of environmental carcinogens to asbestos and mineral fibres — G. Harvey, M. Pagé, et al. (1984)

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