Real-time breath analysis towards a healthy human breath profile.

The direct analysis of molecules contained within human breath has had significant implications for clinical and diagnostic applications in recent decades. However, attempts to compare one study to another or to reproduce previous work are hampered by: variability between sampling methodologies, human phenotypic variability, complex interactions between compounds within breath, and confounding signals from comorbidities. Towards this end, we have endeavored to create an averaged healthy human 'profile' against which follow-on studies might be compared. Through the use of direct secondary electrospray ionization combined with a high-resolution mass spectrometry and in-house bioinformatics pipeline, we seek to curate an average healthy human profile for breath and use this model to distinguish differences inter- and intra-day for human volunteers. Breath samples were significantly different in PERMANOVA analysis and ANOSIM analysis based on Time of Day, Participant ID, Date of Sample, Sex of Participant, and Age of Participant (p< 0.001). Optimal binning analysis identify strong associations between specific features and variables. These include 227 breath features identified as unique identifiers for 28 of the 31 participants. Four signals were identified to be strongly associated with female participants and one with male participants. A total of 37 signals were identified to be strongly associated with the time-of-day samples were taken. Threshold indicator taxa analysis indicated a shift in significant breath features across the age gradient of participants with peak disruption of breath metabolites occurring at around age 32. Forty-eight features were identified after filtering from which a healthy human breath profile for all participants was created.

Learning and memory performance following acute intranasal insulin administration in abstinent smokers.

The highest incidence of relapse to smoking occurs within the first 2 weeks of a cessation attempt. In addition to enhanced nicotine craving, this phase of smoking cessation is also marked by learning and memory dysfunction. Many smokers are not able to overcome these symptoms, and they relapse to smoking shortly after trying to quit. In two clinical studies, we evaluated intranasal insulin for efficacy in improving learning and memory function during nicotine withdrawal. Our first study was a crossover evaluation (N = 19) following 20 hr of smoking abstinence. Study 2 was a parallel design study (N = 50) following 16 hr of abstinence. Intranasal insulin (60 IU) dose was administered in both studies and cognitive function was measured using California Verbal Learning Test-II. Intranasal insulin did not improve learning over the 5 verbal learning trials. In addition, intranasal insulin did not improve either short- or long-delay recall in either study. In summary, the one-time administration of intranasal insulin does not improve verbal learning and memory in smokers. Whether longer administration schedules may be of benefit should be evaluated in future studies.

Biomechanical analysis of mandibular angle fractures.

BACKGROUND: Clinical evidence has suggested that minimal fixation can reduce complications of mandibular angle fractures, though no detailed biomechanical model has yet explored this unique and somewhat unexpected finding. METHODS: The current study uses finite element analysis to biomechanically evaluate different fixation schemes used to fixate mandibular angle fractures. Three fixation scenarios were considered: a single tension band at the superior mandibular border, a single bicortical angle compression plate at the inferior border and the tension band and bicortical plate used together. RESULTS: The dual plate model incurred the lowest von Mises stresses in the plates and the lowest principal strain in the callus. The tension band model observed the highest plate and screw von Mises stresses, but had fracture-site callus strain near to that of the dual plate model. The bicortical angle compression plate model observed the highest fracture-site callus strain. CONCLUSION: The results from this study support the use of the single tension band configuration as a less invasive fixation approach to fractures of the mandibular angle. This is the first known study to explore and confirm clinical observations of angle fracture fixation outcomes with a detailed biomechanical modeling methodology.