The content of mast cells in the pleural membranes, pericardium and liver capsule of cattle and horse; a comparison with earlier observations and assays of heparin and of histamine in these tissues.

This research focused on counting the number of mast cells found in certain body tissues of cattle and horses, specifically the pleura, pericardium, and capsula hepatis. Notably, the researchers found the cattle’s liver capsule contained a significantly higher amount of mast cells than other tissues. This study also debates the source of the high histamine content in these tissues.

Counting Mast Cells in Various Tissues

• The researchers examined the amount of mast cells, which are part of the immune system, in the pleura, pericardium, and capsula hepatis of cattle and horses.
• These specific tissues were chosen for analysis as their mast cell contents have not been thoroughly studied before.

Findings from the Study

• The results of the study found the cattle’s capsula hepatis, or liver capsule, contained 5-10 times the number of mast cells compared to the other tissues studied.
• The pleura pulmonalis, or the lung’s pleural membrane, had a notably lower mast cell count than the liver capsule.

Potential Source of Histamines

• The researchers considered the results of a previous study by Riley and coworkers that found a high histamine content in the ox’s pleura.
• Given the low mast cell count in the lung’s pleural membrane, the researchers proposed that histamines, a compound involved in local immune responses, might be produced not just by mast cells, but also by other elements in these tissues.