title: Validation of the biogenics research chamber for Juniperus ashei (mountain cedar) pollen.
abstract: BACKGROUND
  Pollen challenge chambers have been used to evaluate medication in allergic rhinoconjunctivitis under controlled conditions.
  
  
  OBJECTIVE
  To validate a facility for the study of subjects' responses to inhalational challenges with Juniperus ashei (mountain cedar) pollen.
  
  
  METHODS
  Two chambers, 307 m(3) and 188 m(3), seating 50 and 25 individuals, respectively, were constructed with clean room materials. The computer-controlled air handler used powered diffusers and exhausts to maintain a laminar flow. Pollen was delivered by a feeder into a vortex created by an eductor through a series of stainless steel tubes. Nonprimed mountain cedar sensitive and healthy control subjects were exposed to a masked sham air run and increasing increments of pollen during a 5-hour period outside the natural season. These individuals were then exposed for 2-hour periods for up to 4 sequential days at fixed pollen counts to demonstrate effects of priming.
  
  
  RESULTS
  Airflow from diffusers and exhausts maintained 12 exchange cycles per hour. Pollen counts ranged from 1,300 to 12,000 grains/m(3). None of the subjects responded during the masked sham run. Healthy controls did not respond. Nonprimed subjects had an inadequate response. Primed subjects responded symptomatically within a period adequate for entry into studies. There were no serious adverse responses.
  
  
  CONCLUSIONS
  The chambers functioned within the parameters for which they were designed. Subjects did not respond to a sham run. Priming runs were required to stimulate symptoms at levels in a timeframe sufficient for pharmacologic studies. Pollen counts 3 to 4 times the average seasonal counts were required to elicit significant symptoms.
authors.affiliation: Biogenics Research Institute, San Antonio, Texas 78229, USA. robert.jacobs7025@sbcglobal.net
authors.forename: Robert L
authors.initials: RL
authors.lastname: Jacobs
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Ramirez
authors.forename: Charles P
authors.initials: CP
authors.lastname: Andrews
mesh_terms: D000485:Allergens / Q000276:immunology*; D001273:Atmosphere Exposure Chambers; D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods; D004780:Environment, Controlled; D005240:Feasibility Studies; D006801:Humans; D007114:Immunization; D018653:Juniperus; D011058:Pollen / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D000485:Allergens