Fifteen cows among a herd of 50 suckler cows and calves rapidly lost body condition and became dull and anorexic after grazing pasture containing bog asphodel (Narthecium ossifragum) during the summer of 1989. The affected cows had evidence of kidney damage characterised by elevated plasma urea and creatinine concentrations. Eleven cows died and diffuse renal tubular necrosis was present in three cows which were examined post mortem. Similar renal lesions were reproduced experimentally by feeding bog asphodel to a healthy calf.

Inhibitors of arachidonic acid metabolism were characterized by their ability to modulate slow reacting substance (SRS) and prostaglandin E2 (PGE2) release from stimulated mouse peritoneal macrophages in-vitro. Differential effects of cyclo-oxygenase (CO) and lipoxygenase (LO) enzyme inhibitors and compounds which inhibit both enzymes were demonstrated using several animal models of inflammation. Carrageenan-impregnated sponges implanted subcutaneously in rats and immune-complexes injected intraperitoneally in mice produced inflammatory responses characterized respectively by polymorphonuclear (PMN) cell infiltration and by increased vascular permeability. Dual CO/LO inhibitors (eg. BW 755c and timegadine) were capable of suppressing both parameters and reduced SRS and PGE2 formation in-vivo. In contrast, selective CO inhibitors (e.g. indomethacin, naproxen and R-830) were less active against permeability, and potentiated SRS release. Although selective CO inhibitors reduced PMN migration, this occurred at doses which exceeded those required for inhibition of PGE2. Compounds possessing LO inhibitory activity suppressed the cellular component of an Arthus type reaction in the rat pleural cavity, but were less active than selective CO inhibitors against carrageenan-induced paw oedema in rats.

No abstract

No abstract