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 (1979).

The study

• Authors: L. D. Palekar, C. M. Spooner, D. L. Coffin
• Published: Annals of the New York Academy of Sciences, pp. 673-?; ISSN 0077-8923/79/0330-0673 (1979)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This laboratory study tested whether crystal habit (shape) affects how much minerals damage cells. The authors used four samples from the cummingtonite-grunerite series: asbestiform grunerite (the UICC amosite standard, from South Africa), acicular (needle-like) grunerite from Labrador, Canada, and semiasbestiform and acicular cummingtonite from the Homestake Mine, South Dakota. Ground samples were tested on sheep red blood cells (hemolysis) and on Chinese hamster ovary cells (colony survival). At comparable surface areas, amosite was the most damaging: at 0.05 mg/ml, fewer than 25 percent of hamster cell colonies survived. Acicular grunerite of comparable surface area caused no hemolysis and was nontoxic even at 0.50 mg/ml. The two cummingtonites fell in between. When ground finer, acicular grunerite became hemolytic and cytotoxic. No relationship with surface charge was seen. The authors concluded that crystallization habit plays an important role in these effects. They also concluded that nonasbestiform minerals could possibly be hazardous to human health at higher doses and surface areas. They noted that surface areas of the finer grunerite 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: In vitro laboratory experiment: hemolysis of sheep red blood cells and cytotoxicity (colony survival) in Chinese hamster ovary cells
• Who was studied: Four mineral samples of the cummingtonite-grunerite series: asbestiform grunerite (UICC amosite standard, South African), acicular grunerite (Smallwood Mine, Wabush, Labrador, Canada), semiasbestiform cummingtonite and acicular cummingtonite (both Homestake Mine, South Dakota, USA). They were tested on sheep erythrocytes and on a Chinese hamster ovary (CHO) cell line.
• Exposure: Particles of the four minerals, ground to various particle sizes. Hemolysis was tested at 20 mg/ml. CHO cell cytotoxicity was tested at doses from 0.05 to 0.50 mg/ml over 6 days. Samples were characterized for chemical composition, surface area and surface charge.
• Main results:
  • In the hemolysis test, asbestiform grunerite (UICC amosite) with a surface area of 4.13 m2/g caused hemolysis printed as "53 3" percent (likely 53.3). Acicular grunerite with a surface area of 2.82 m2/g caused no hemolysis.
  • Semiasbestiform cummingtonite (3.88 m2/g) and acicular cummingtonite (3.76 m2/g) caused roughly 32 and 30 percent hemolysis. The authors reported no difference in hemolytic activity between these two samples.
  • Acicular grunerite that caused no hemolysis caused 10 percent hemolysis when ground further. Finer samples caused up to 40 percent hemolysis.
  • In CHO cells, asbestiform grunerite (amosite, 4.13 m2/g) was the most toxic. Fewer than 25 percent of clones survived at 0.05 mg/ml, 5 percent at 0.1 mg/ml and 1 percent at 0.2 mg/ml.
  • Acicular grunerite of comparable surface area (2.82 m2/g, Sample A) was nontoxic to CHO cells even at 0.50 mg/ml.
  • The finest acicular grunerite sample (Sample D) was toxic from 0.20 mg/ml. Clone survival was 75 percent at 0.20, 55 percent at 0.30, 40 percent at 0.40 and 35 percent at 0.50 mg/ml.
  • Semiasbestiform cummingtonite (3.88 m2/g) left 85 percent and 70 percent of CHO clones surviving at 0.05 and 0.10 mg/ml. No toxicity was seen at these doses with acicular cummingtonite (3.76 m2/g). The authors saw no significant difference at higher doses.
  • The authors found no correlation between surface charge and cytotoxicity, and no apparent relationship between surface charge and hemolysis.
• The authors' conclusion: The authors concluded that crystallization habit plays an important role in hemolysis and cytotoxicity. At comparable surface area, the samples ranked in decreasing order of effect: asbestiform grunerite (amosite), semiasbestiform cummingtonite, acicular cummingtonite, acicular grunerite. They concluded it seems possible that nonasbestiform minerals could also be hazardous to human health at higher doses and surface areas, and that more research is required.
• Limitations the authors state:
  • Surface areas of the finer acicular grunerite samples were not available, so the authors could not make a conclusive correlation between surface area and biological activity.
  • The surface charge of particles after exposure to the cells was not calculated, and more work is needed to establish the role of surface charge.
  • No quantitative measure exists for the degree of asbestiform development, so "semiasbestiform" is a descriptive term.
  • Flexible (more asbestiform) crystals were removed from the acicular cummingtonite sample by eye, and some were probably missed.

Topics

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

Browse return to medical research.