Effect of intravascular neutrophil chemotactic factors on blood neutrophil and platelet kinetics
Intravenous infusion of an analogue (f-met-leu-phe (FMLP)) of a bacterial-derived polymorphonuclear leukocyte (PMNL) chemotactic factor, or of the complement-derived chemotactic stimulus, zymosan-activated plasma (ZAP, containing C5ades Arg) into rabbits induces acute PMNL margination in the pulmonary vasculature. The pulmonary PMNL sequestration is accompanied by thrombocytopenia. Because of the role platelets and PMNLs play in hemostasis and defense against infection, we studied the fate of these blood elements following sequestration induced by chemotactic factors. By employing 111In-labelled platelets and external radioisotope scanning, platelets were found to sequester in the pulmonary vasculature during FMLP infusion. Simultaneous 51Cr PMNL and 111In-platelet studies showed that following sequestration, PMNLs returned to the circulation and disappeared with a normal half-life (T1/2) whereas the T1/2 of the platelets was markedly shortened (T1/2 of control = 49 +/- 3.0 hr; FMLP or ZAP infused T1/2 = 27 +/- 2.7 hr). Infusion of platelet-activating factor (PAF) induced PMN and platelet sequestration with similar abnormalities in platelet kinetics. Studies with 51Cr- and 14C-serotonin-labelled platelets showed that platelets did not release serotonin during FMLP, ZAP, or low dose PAF-induced sequestration. In contrast to platelet survival, platelet size, platelet aggregation responses, and platelet glycoproteins were not affected by transient sequestration. These results indicate that during PMNL margination induced by relatively pure PMNL stimuli such as FMLP, platelets may reversibly marginate and subsequently be cleared at an accelerated rate. The reason for accelerated platelet clearance is not a result of circulating platelet aggregates or detectable proteolytic modification of membrane glycoproteins.
- Research Organization:
- Dalhousie Univ., Halifax, Nova Scotia
- OSTI ID:
- 5943663
- Journal Information:
- Am. J. Hematol.; (United States), Journal Name: Am. J. Hematol.; (United States) Vol. 2; ISSN AJHED
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
AZAARENES
AZOLES
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BODY FLUIDS
CARBON 14 COMPOUNDS
CHROMIUM 51
CHROMIUM ISOTOPES
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INDIUM 111
INDIUM ISOTOPES
INDOLES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LEUKOCYTES
MAMMALS
MATERIALS
MINUTES LIVING RADIOISOTOPES
NEUROREGULATORS
NEUTROPHILS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRROLES
RABBITS
RADIOISOTOPE SCANNING
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
SEROTONIN
SURVIVAL TIME
SYMPATHOMIMETICS
TRACER TECHNIQUES
TRYPTAMINES
VERTEBRATES