Measurement of blood flow and vascular permeability changes in response to 12-O-tetradecanoyl-phorbol-13-acetate and to asbestos fibers

Our plain-English summary of Measurement of blood flow and vascular permeability changes in response to 12-O-tetradecanoyl-phorbol-13-acetate and to asbestos fibers, by J.A. Hamilton, P. Vadas, J.B. Hay (Journal of Toxicology and Environmental Health, 1981).

The study

• Authors: J.A. Hamilton, P. Vadas, J.B. Hay
• Journal: Journal of Toxicology and Environmental Health
• Published: 1981;8(1-2):205-14
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The hyperemia (increased blood flow) and vascular permeability changes induced in rabbit skin by the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate and by asbestos fibers have been quantitated. The resultant hyperemia, measured with radiolabeled microspheres, was inhibited in both cases by steroidal and nonsteroidal anti-inflammatory drugs. Since the inflammatory responses resulting from exposure to these agents might be important for the subsequent development of neoplasms, it is proposed that such a specific and quantitative technique be used to analyze the components of these inflammatory responses in more detail.

In plain English

This was a laboratory experiment in rabbits, not a study of people. The authors measured increased blood flow (hyperemia) and blood-vessel leakiness (vascular permeability) in rabbit skin. They either applied the tumor promoter TPA to the skin or injected asbestos fibers into it. TPA increased blood flow, in some experiments up to 10 times that of control skin, and the drugs indomethacin, ETYA and dexamethasone inhibited this increase. Two chrysotile samples (IARC chrysotile A and Calidria chrysotile) also increased blood flow. In unpublished observations, two further chrysotile samples, IARC amosite, IARC crocidolite and a quartz sample produced blood flow generally 2-4 times that of a saline control. Vessel leakiness was generally not significantly different from controls, though the authors noted that such changes can last only minutes. In preliminary experiments, indomethacin and dexamethasone partially inhibited the response to chrysotile A. The authors concluded that TPA and asbestos fibers caused similar acute inflammatory responses in rabbit skin.

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 measuring skin blood flow (with radiolabeled microspheres) and vascular permeability (with radiolabeled albumin)
• Who was studied: Shaven, randomly bred albino rabbits weighing 2.5-3 kg. Three rabbits were used per experiment, and the figures show data for one rabbit.
• Exposure: TPA (a tumor promoter) applied to the skin at several doses. Intradermal injections (0.2 ml) of 1 mg IARC chrysotile A or Calidria chrysotile. In unpublished observations, IARC chrysotile B, Canadian chrysotile, IARC amosite, IARC crocidolite and a quartz sample were injected at 500-1000 micrograms.
• Main results:
  • TPA on rabbit skin increased blood flow. In some experiments the increase was as much as 10 times that in acetone-treated or untreated skin.
  • After TPA, vascular permeability values were not significantly different from control values.
  • Both steroidal (dexamethasone) and nonsteroidal (indomethacin and ETYA) drugs inhibited the TPA-induced increase in blood flow.
  • Both chrysotile samples (IARC chrysotile A and Calidria chrysotile) increased blood flow. Vascular permeability values were again not significantly different from controls.
  • In unpublished observations, IARC chrysotile B, Canadian chrysotile, IARC amosite, IARC crocidolite and a quartz sample produced blood flow generally 2-4 times that of a normal saline control.
  • With all samples, increased blood flow was present at 1-2 hours and peaked at 6-24 hours after injection.
  • Increased blood flow could still be seen in 2-month-old (chronic) lesions.
  • In preliminary experiments, indomethacin and dexamethasone partially inhibited the increased blood flow produced by chrysotile A.
• The authors' conclusion: The authors concluded that TPA and asbestos fibers caused similar acute inflammatory responses in rabbit skin, and that the same anti-inflammatory drugs inhibited the increased blood flow in each case. They suggested similar approaches be used in organs such as the lung.
• Limitations the authors state:
  • Vascular permeability changes may last only a few minutes, so the measurement times used may have missed them. The authors said shorter time points were being examined.
  • Vascular permeability changes can vary widely between animal species.
  • The increased blood flow in chronic lesions could be due to growth of new blood vessels.

Mines named here

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

• Santa Rita mine, Joaquin Ridge near Coalinga, California

All asbestos mines

Topics

Medical terms in this study, explained in our Lexicon: Neoplasm.

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