title: Platelet aggregation responses in clinically healthy adult llamas.
abstract: BACKGROUND
  Limited information exists regarding hemostasis in camelids despite the importance of platelet function testing in the accurate identification of platelet disorders. As further importation of llamas to North America is restricted, variability in breeding stock will continue to decrease, potentially leading to an increase in heritable bleeding disorders.
  
  
  OBJECTIVE
  The objective of this study was to measure platelet aggregation responses in clinically healthy llamas and provide baseline data to which abnormal platelet function may be compared in the future.
  
  
  METHODS
  Blood samples were collected from 39 healthy adult llamas, citrated, and centrifuged to produce platelet-rich plasma (PRP). Within 4 hours of the blood draw, 20 microL of each agonist reagent were added to 180 microL of PRP. Final concentrations of agonists were 2 x 10(-5) M ADP, 0.19 mg collagen/mL PRP, 1 x 10(-4) M epinephrine, and 500 microg arachidonic acid/mL PRP.
  
  
  RESULTS
  Llama platelets were most responsive to ADP and collagen, with a maximum percent aggregation (mean+/-SD) of 71.3+/-18.6% and 55.8+/-19% and aggregation rates of 9.5+/-3.9 and 6.7+/-3.7 cm/min, respectively. Llama platelet aggregation in response to epinephrine and arachidonic acid was minimal to absent.
  
  
  CONCLUSIONS
  This study is the first of its kind to establish baseline values for platelet aggregation in healthy adult llamas.
authors.affiliation: College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Rosanne M
authors.initials: RM
authors.lastname: Gilbert
authors.forename: Karyn E
authors.initials: KE
authors.lastname: Bird
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Kutzler
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000502:physiology*; D002161:Camelids, New World / Q000097:blood* / Q000502:physiology; D005260:Female; D008297:Male; D010974:Platelet Aggregation / Q000502:physiology*