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The use of radioactive microspheres to quantitate hyperemia in dermal inflammatory sites
Abstract:
A variety of dermal lesions produced by PGE1, tuberculin, and allogeneic lymphocytes were induced in rabbits, guinea pigs, and sheep, respectively. Microspheres labeled with 85Sr were injected into the ascending aorta, and the distribution of radioactivity in the lesions, saline control sites, and various major organs was assessed. It was concluded that the trapping of the microspheres was related to the degree of hyperemia induced, and that this technique enabled a quantitative measure of the blood flow. PGE1 was found to be a potent mediator of hyperemia and to have a significant effect on the blood flow at a dose of 1 ng. The blood flow to cellular hypersensitivity reactions was measured and the capacity of the skin to accomodate a large increase in flow during the inflammatory response was established.
Insights
This study quantifies blood flow in dermal lesions using radiolabeled microspheres. Prostaglandin E1 (PGE1) significantly increases blood flow, demonstrating a new method for measuring inflammatory responses.
Area of Science:
- Vascular Biology
- Immunology
- Pharmacology
Background:
- Dermal lesions can be induced by various agents like Prostaglandin E1 (PGE1), tuberculin, and allogeneic lymphocytes.
- Assessing blood flow changes in these lesions is crucial for understanding inflammatory processes.
Purpose of the Study:
- To develop and validate a method for quantitatively measuring blood flow in induced dermal lesions.
- To investigate the role of PGE1 as a mediator of hyperemia and its effect on blood flow.
- To measure blood flow in cellular hypersensitivity reactions.
Main Methods:
- Induction of dermal lesions in rabbits, guinea pigs, and sheep using PGE1, tuberculin, and allogeneic lymphocytes, respectively.
- Intra-aortic injection of 85Sr-labeled microspheres.
- Assessment of radioactivity distribution in lesions, control sites, and organs.
Main Results:
- Microsphere trapping correlated with the degree of induced hyperemia, enabling quantitative blood flow measurement.
- PGE1 was identified as a potent hyperemia mediator, significantly affecting blood flow at 1 ng.
- The study established the skin's capacity for increased blood flow during inflammatory responses.
Conclusions:
- The microsphere distribution technique provides a quantitative measure of blood flow in dermal inflammatory lesions.
- PGE1 plays a significant role in mediating hyperemia and altering local blood flow.
- The findings highlight the dynamic changes in skin blood flow during inflammatory reactions.