Missing link between the Hayward and Rodgers Creek faults.

The next major earthquake to strike the ~7 million residents of the San Francisco Bay Area will most likely result from rupture of the Hayward or Rodgers Creek faults. Until now, the relationship between these two faults beneath San Pablo Bay has been a mystery. Detailed subsurface imaging provides definitive evidence of active faulting along the Hayward fault as it traverses San Pablo Bay and bends ~10° to the right toward the Rodgers Creek fault.

Safety assessment of inhaled xylitol in subjects with cystic fibrosis.

Background: Xylitol is a 5-carbon sugar that can lower the airway surface salt concentration, thus enhancing innate immunity. We tested the safety and tolerability of aerosolized iso-osmotic xylitol in subjects with cystic fibrosis.

Methods: In this pilot study, 6 subjects with cystic fibrosis and an FEV1>60% predicted underwent a baseline spirometry followed by exposures to aerosolized saline (10 ml) and 5% xylitol (10 ml).

Safety of incremental inhaled lipopolysaccharide challenge in humans.

Background: Inhalation of environmental endotoxin is important in the pathogenesis of asthma and other environmental airway diseases. Inhaled airway challenge using lipopolysaccharide in humans has been performed for over 20 years to assess the airway response to endotoxin. However, there are no published data on the short-term safety of endotoxin inhalation protocols.

Bronchoscopic assessment of airway retention time of aerosolized xylitol.

Background: Human airway surface liquid (ASL) has abundant antimicrobial peptides whose potency increases as the salt concentration decreases. Xylitol is a 5-carbon sugar that has the ability to lower ASL salt concentration, potentially enhancing innate immunity. Xylitol was detected for 8 hours in the ASL after application in airway epithelium in vitro.

Safety assessment of inhaled xylitol in mice and healthy volunteers.

Background: Xylitol is a 5-carbon sugar that can lower the airway surface salt concentration, thus enhancing innate immunity. We tested the safety and tolerability of aerosolized iso-osmotic xylitol in mice and human volunteers.

Methods: This was a prospective cohort study of C57Bl/6 mice in an animal laboratory and healthy human volunteers at the clinical research center of a university hospital.

Experimental human exposure to inhaled grain dust and ammonia: towards a model of concentrated animal feeding operations.

Background: Ammonia and endotoxin-rich dust are present in high concentrations in swine confinement facilities; exposure to this environment is linked to workers' respiratory problems. We hypothesized that experimental exposure to ammonia and dust would impair pulmonary function, and that these exposures would be synergistic.

Methods: We exposed six normal subjects and eight subjects with mild asthma to ammonia (16-25 ppm) and/or endotoxin-rich grain dust (4 mg/m3).

Characterization of a hooded human exposure apparatus for inhalation of gases and aerosols.

A human exposure apparatus was designed to administer a gas and/or aerosol directly to the subject's face. This apparatus utilized a hood associated with a powered air-purifying respirator. The design criteria included the need to maximize subject comfort, maintain consistent atmospheres of a gas or dust within the hood, and the accurate use of direct-reading instruments to monitor exposure levels.