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A Buret

Publications and source records attributed to A Buret.

39 records · Page 3Linked to original sources
PubMed1988

Mast cell protease release and mucosal ultrastructure during intestinal anaphylaxis in the rat.

Intestinal anaphylaxis is associated with disturbances in gut function that are antigen-specific and dependent on mast cell degranulation. Using an animal model of intestinal anaphylaxis, we have correlated alterations in water and electrolyte transport, associated with intraluminal challenge, with specific intestinal mucosal mast cell degranulation by following systemic as well as local release of rat mast cell protease II. This protease is specific for intestinal mucosal mast cells and is known to selectively attack type IV collagen, which is found in basement membranes. Intraluminal antigen challenge in sensitized animals dramatically increased serum and intraluminal levels of rat mast cell protease II. Serum levels continued to rise throughout the duration of antigen challenge. Although light microscopy of challenged intestine demonstrated little distortion of mucosal architecture, ultrastructural examination revealed significant disruption to the basement membrane and underlying collagenous matrix of the intestinal mucosa. Our findings indicate that during mucosal immunoglobulin E-mediated reactions, rat mast cell protease II is released and is associated with ultrastructural changes in the intestinal mucosa. The systemic appearance of this specific protease provides a serum marker of intestinal anaphylaxis.

Anaphylaxis↗
PubMed1988

Intestinal anaphylaxis: in vivo and in vitro studies of the rat proximal colon.

The response of the rat proximal colon to an immunoglobulin E (IgE)-mediated hypersensitivity reaction was examined. Rats were sensitized to egg albumin (EA) by intraperitoneal injection, and serum titers of specific anti-EA IgE were measured at 14 days. Sensitized animals had titers of greater than or equal to 1:64, whereas no anti-EA IgE antibodies were detected in controls. Water and electrolyte absorption in the proximal colon, before and during antigen challenge, was measured by in vivo marker perfusion. Antigen challenge resulted in significant inhibition of water, Na+, Cl-, and K+ absorption in vivo. Proximal colonic tissue from sensitized and control animals was studied in Ussing chambers under short-circuited conditions. Antigen challenge of sensitized tissue resulted in significant increases in short-circuit current due to the induction of active Cl- secretion. No such changes were seen in control tissue. The abnormalities induced by antigen challenge in tissue from sensitized animals was blocked by doxantrazole (10(-3) M), a mast cell stabilizer. The findings indicate that IgE-mediated reactions in rat proximal colon to a food protein cause pertubations in water and electrolyte transport secondary to active Cl- secretion and these abnormalities appear to be due to mast cell degranulation.

Anaphylaxis↗