The Influence of Fiberglas Plastic Dust on Tuberculosis

Our plain-English summary of The Influence of Fiberglas Plastic Dust on Tuberculosis, by G.W.H. Schepers (1958).

The study

• Author: G.W.H. Schepers
• Published: American Review of Tuberculosis and Pulmonary Diseases, Volume 78 No4. October 1958. Received March 10th 1958
• 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 was an animal experiment on dust from Fiberglas-plastic. It did not study asbestos. The author infected female guinea pigs by inhalation with the R1Rv strain of human tuberculosis bacteria. The animals then breathed dust from one of two products: glass fibers in polyester resin with either a calcium sulfate filler or a calcium carbonate filler. In all, 113 guinea pigs were used. Some animals entered the dust chamber right after infection and others months later. Infected animals that breathed no dust served as controls. Average dust levels were 390 million particles per cubic foot for the calcium sulfate dust and 338 million for the calcium carbonate dust. The calcium sulfate dust worsened the infection only slightly, and healing began early. With the calcium carbonate dust, lung tubercles were more numerous and larger than in controls during the first year, but spreading lesions later healed despite continued exposure. The author concluded that both dusts caused limited, transient worsening of the infection, more so with the calcium carbonate filler. The author noted that weaker bacteria during the calcium sulfate experiment temper this comparison.

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: Animal experiment (inhalation study in guinea pigs infected with tuberculosis, with microscopic examination of the lungs and other organs)
• Who was studied: 113 female guinea pigs of the Saranac Laboratory albino strain, studied at the Saranac Laboratory, Saranac Lake, New York. In each experiment, 25 animals were exposed to dust immediately after infection and 26 were exposed after a delay. Infected animals not exposed to dust served as controls.
• Exposure: Inhaled Fiberglas-plastic dust: glass fibers (about 15 per cent), polyester resin (about 35 to 60 per cent), and either calcium sulfate or calcium carbonate filler (about 25 to 45 per cent). Calcium sulfate dust (Experiment 1245): average 390 million particles per cubic foot over ten months. Calcium carbonate dust: average 338 million particles per cubic foot, range 52 to 792 million, over twenty-four months.
• Main results:
  • Guinea pigs exposed to calcium sulfate dust immediately after infection: the infection was worsened only slightly, and healing began early despite continued dust exposure.
  • Guinea pigs exposed to calcium carbonate dust immediately after infection: during the first year of exposure, lung tubercles were more numerous and larger than in the control guinea pigs.
  • In the calcium carbonate group, the increased tuberculosis was limited to the lung tissue, and the lymph nodes showed virtually no increase.
  • The worsened tuberculosis did not worsen the dust-related lung reaction at the same time. Clusters of dust-filled cells were less extensive than in uninfected control animals.
  • Guinea pigs exposed to calcium sulfate dust after a delay: exposure starting within two months of infection mildly and briefly reactivated the infection. Exposure starting after four and six months speeded the healing.
  • Guinea pigs exposed to calcium carbonate dust after a delay: the tuberculous response was enhanced for a time, and the tubercles then healed relatively rapidly.
  • The tuberculous response did not rise in step with the amount or length of dust exposure.
  • Previously spreading tubercles healed even though dust exposure continued.
• The authors' conclusion: The author concluded that both inhaled Fiberglas-plastic dusts caused limited, transient worsening of the tuberculous infection. The infection was more vigorous and lasted longer in animals exposed to the dust with the calcium carbonate filler than in those exposed to the dust with the calcium sulfate filler.
• Limitations the authors state:
  • The tuberculosis culture was going through a phase of reduced virulence during the calcium sulfate experiment and had returned to normal for the calcium carbonate experiment. The author stated that this tempers the inferences drawn from the contrasting results.
  • The two experiments were started ten months apart, and the virulence of the bacterial culture fluctuated for unknown reasons.

Topics

Medical terms in this study, explained in our Lexicon: Million Particles per Cubic Foot (mppcf).

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