The control animals were instilled with 50 μL of sterile pyrogen-free water. Correct insertion of the tube into the trachea was assured by using a modified pneumotachometer (National Research Centre for the Working Environment, Copenhagen, Denmark)

[12]. To establish a time-response relationship (experiment 4), 10 mice per dose were exposed Selleckchem eFT508 by i.t instillations to either 3.4 × 106 CFU Vectobac® or 3.5 × 105 CFU Dipel®. BAL fluids were collected 4 hours, 24 hours or 4 days post GS1101 exposure and cells were counted and differentiated as described below. Subsequently, in order to establish a dose-response relationship (experiment 3), 10 mice per dose was exposed by i.t instillations to a Vectobac® dose of 1.25 × 104, 2 × 105, 4.2 × 105 or 1.2 × 106 CFU, respectively. BAL fluids were collected 24 hours post exposure and cells were counted and differentiated as described below. For the sub-chronic study (experiment 5) the instilled doses were 3.4 × 106 CFU for Vectobac® and 3.5 × 105 for Dipel®. Repeated aerosol inhalations (experiment 6) Mice (n = 9 per group) were inserted into body plethysmographs that were connected to the exposure chamber. The respiratory parameters were obtained

for each mouse from a Fleisch pneumotachograph connected to each plethysmograph that allows continuously monitoring of the parameters [13, 14]. The exposures were preceded by a period that allowed the mice to adapt to the plethysmographs. Then, a 15 min. period was used to establish baseline (control) values of the respiratory parameters. LY333531 datasheet This period was followed by a 60 min. exposure period and a 15 min recovery period. Mice were exposed 60 min/day for 5 days per week for two weeks with a two-day break in-between. The dose of 5 × 104 CFU per mouse per exposure was chosen to mimic occupational exposure [15]. Suspensions of bacteria were delivered from a glass syringe, administered by an infusion pump (New England

Medical Instruments Inc., Medway, MA, USA) and via a polyethylene tube connected to a Pitt. No. 1 aerosol generator [16]. The aerosol was mixed through a Vigreaux-column and led to a glass/stainless steel exposure chamber as described Sodium butyrate [17]. Total flow rate through the chamber was 20 L/min and the air input through the aerosol generator was 14 L/min. The aerosol generator and all related equipments were thoroughly cleaned between exposure sessions. During the aerosol exposures, air samples were collected from the breathing zone of the mice for determination of particle size distribution, real-time particle counts and aerosol CFU concentration. This was done by APS at a flow of 5 L/min, LHPC at 2 L/min and by a filter method GSP at 3.5 L/min. The APS monitored the size distribution of particles in the range from 0.542 to 19.81 μm (aerodynamic diameter) in the exposure chamber. Real time particle counts in the exposure chamber was counted by LHPC in the ranges 0.7-2.