Life span and tissue distribution of 111indium-labeled blood platelets in hypomagnesemic lambs
Circulating platelets may be activated by exposed triple-helical collagen in atherosclerotic lesions in Mg-deficient ruminants. Autologous platelets, labeled in vitro with 111In and determined to be active, were injected into 5 hypomagnesemic and 3 control lambs fed semipurified diets with 100 or 2,000 mg of Mg/kg of feed for 3 months. During the first 68 hours, 111In concentrations were 11 times higher in packed cells than in plasma. Packed-cell 111In increased 60% during the first 2 hours, probably due to initial tissue sequestration and later release of labeled platelets. Thereafter, platelet half-life span averaged 60 and 63 hours for hypomagnesemic and control lambs. After 68 hours, lambs were injected with native vascular collagen fibrils at 500 micrograms/kg of body weight to initiate reversible platelet aggregation. Within 1 minute, 83% of packed-cell 111In disappeared from circulation. Thirty minutes later, the lambs were euthanatized and necropsied and in the lungs, liver, and spleen, 111In averaged 24%, 19%, and 9%, respectively, of 111In injected 68 hours earlier. Organ deposits were not affected by Mg intake, but 111In in the lungs was somewhat lower in 2 lambs injected with inactivated collagen. Pathologic changes induced by reversible platelet aggregation were compatible with right ventricular failure complicated by pulmonary edema, similar to changes in hypomagnesemic lambs that died spontaneously. Platelets in blood exposed to vascular lesions in hypomagnesemic ruminants could be a major mortality risk factor in grass tetany disease.
- Research Organization:
- Comparative Animal Research Laboratory, Oak Ridge, TN
- OSTI ID:
- 5502685
- Journal Information:
- Am. J. Vet. Res.; (United States), Vol. 44:5
- Country of Publication:
- United States
- Language:
- English
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MAGNESIUM
NUTRITIONAL DEFICIENCY
SHEEP
ARTERIOSCLEROSIS
BLOOD PLATELETS
INDIUM
LABELLING
LIFE SPAN
LIVER
LUNGS
METABOLIC DISEASES
NUTRITION
SPLEEN
TISSUE DISTRIBUTION
ALKALINE EARTH METALS
ANIMALS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY
BODY FLUIDS
CARDIOVASCULAR DISEASES
DIGESTIVE SYSTEM
DISEASES
DISTRIBUTION
DOMESTIC ANIMALS
ELEMENTS
GLANDS
MAMMALS
MATERIALS
METALS
ORGANS
RESPIRATORY SYSTEM
RUMINANTS
VASCULAR DISEASES
VERTEBRATES
553001* - Agriculture & Food Technology- Tracer Techniques- (-1987)