Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027947 (neutropenia)
 17,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neonatal and young animals fail to develop antigen-induced, lethal, systemic anaphylactic reactions. Recent evidence has documented that, in the adult rabbit, an unusual phospholipid autacoid, platelet-activating factor, induces almost all of the physiologic events associated with IgE-induced anaphylaxis. Thus, in the present study, the intravascular alterations after intravenous infusion of synthetic platelet-activating factor (1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine; AGEPC) into young rabbits were examined. In comparison to 13-week-old, adult rabbits, the intravascular infusion of greater than 1.0 micrograms/kg AGEPC was not lethal in rabbits of 8 weeks of age or less. In dose-response studies, the amount of AGEPC required to induce a lethal response in 50% of the animals tested (LD50) was found to inversely correlate with age. In contrast, AGEPC-induced platelet aggregation in vitro was not affected by the age of the donor animal. Consistent with age-independent platelet responsiveness in vitro, AGEPC-induced thrombocytopenia and intravascular accumulation of platelet factor 4 and thromboxane B2 were also unaffected by animal age. Neutropenia and basopenia, as well as platelet and neutrophil sequestration in the pulmonary microvasculature after intravenous AGEPC infusion also were similarly unaffected by animal age. Although the mechanisms which modulate the profound and lethal physiologic responses following AGEPC infusion in the adult rabbit remain to be established, the current study clearly documents an age-dependent acquisition of systemic physiologic sensitivity to AGEPC and/or other mediators released as a result of intravascular AGEPC administration.
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PMID:Ontogeny of the responsiveness to intravenous platelet-activating factor. 362 21

Intravenous infusion of acetyl glyceryl ether phosphorylcholine (AGEPC) into rabbits resulted in an AGEPC dose-dependent elevation of plasma thromboxane B2 (TxB2) levels within 30 seconds. In contrast to AGEPC, the deacetylated derivative, lyso-GEPC (36.8 micrograms), did not increase intravascular TxB2 levels when similarly infused into rabbits. Intravascular TxB2 levels were maximal at 60 seconds after the infusion of 0.61 micrograms AGEPC whereas at higher doses of AGEPC (1.21-2.4 micrograms), plasma TxB2 levels were maximally elevated within 30 seconds after initiation of AGEPC infusion. These acute increases in the intravascular levels of TxB2 were accompanied by the development of thrombocytopenia, neutropenia, and basopenia which occurred concomitantly with AGEPC dose-dependent elevations in the plasma levels of platelet factor 4. Elevations in the plasma TxB2 levels returned to pre-infusion levels within 10-20 minutes after the initiation of AGEPC infusion. Thus, in vivo, one potent phospholipid, AGEPC, stimulates the production of another class of potent lipid mediators, the thromboxanes.
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PMID:Thromboxane B2 (TxB2) release following acetyl glyceryl ether phosphorylcholine (AGEPC) infusion in the rabbit. 683 60

The intravenous infusion of 1-O-hexadecyl/octadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (AGEPC) in baboons (28 micrograms per kg.) induced acute, but reversible, thrombocytopenia and neutropenia and the intravascular release of platelet factor 4 and thromboxane B2. Maximal depression of circulating platelets and neutrophils occurred within 30 seconds after AGEPC infusion and was accompanied by significant elevations in plasma platelet factor 4 and thromboxane B2 levels (p less than 0.02). Hematocrit values increased after AGEPC infusion, but this increase was delayed relative to the other intravascular alterations, i.e., maximal hematocrit values occurred at 10 to 20 minutes after AGEPC infusion.. The thrombocytopenia induced by AGEPC was reversed within 2 to 3 minutes; in contrast, circulating neutrophils did not return to preinfusion levels until 30 minutes after AGEPC infusion. Plasma platelet factor 4 and thromboxane B2 elevations gradually decreased and returned to preinfusion levels within 30 to 60 minutes. The deacetylated derivative of AGEPC, lyso-glyceryl ether phosphorylcholine, had no effect when similarly infused into baboons. These studies demonstrate that the intravenous administration of AGEPC into baboons initiated significant but reversible intravascular alterations; thus, this unusual acetylated alkyl phosphoglyceride may be an important mediator of inflammation in primates, including man.
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PMID:Acetyl glyceryl ether phosphorylcholine. Intravascular alterations following intravenous infusion into the baboon. 730 Feb 44