Asymptomatic, Incidental Quadricuspid Aortic Valve: A Case Report and Discussion of Management.

With its exceeding rarity, there is little research on the quadricuspid aortic valve (QAV) inherently to drive guideline-based management. This leaves physicians without evidence-based guidance on the management of such patients should they come across this finding on imaging or should they care for a symptomatic patient. This article describes the case of an incidentally identified QAV in a patient undergoing treatment for tuberculosis, which seemingly had bicuspid-appearing valve hemodynamics. Additionally, current literature is reviewed to describe classification, presentation, complications, and intervention, with additional exploration and commentary on the lack of guideline-based care.

Radiation dose reduction using novel size 1 and size 0 rectangular collimators in pediatric dental imaging.

OBJECTIVES: Commercial intraoral rectangular collimators are available for collimating to size 2 image receptor. The benefits of reducing the x-ray beam to match the area of the image detector in adult intraoral radiography are endorsed internationally. However, in pediatric dentistry the image receptor can be further decreased to size 1 and 0. METHOD AND MATERIALS: For this study size 1 and 0 rectangular collimators were fabricated using 1.65-mm lead sheets (Rotometals). The custom-fabricated collimators were fixed to the plastic body of a Rinn (Dentsply) Universal Collimator attachment. Aperture sizes were extrapolated based on the active imaging area of size 1 and 0 digital image receptors. A dose area product (DAP) measuring device was used to determine the change in radiation absorbed dose as a function of the imaging field of view. RESULTS: DAP measurements were evaluated in the 31.7 cm2 conventional round collimation, Rinn 12.0 cm2 Universal rectangular collimator, and in the manufactured size 1 (8.25 cm2) and size 0 (5.72 cm2) rectangular collimators. The size 1 collimator had a 32% DAP reduction from the size 2, and a 53% reduction for the size 0. CONCLUSION: Size 1 and size 0 rectangular collimators can be independently manufactured and utilized in pediatric dentistry. This study suggests that a considerable radiation dose reduction is possible in pediatric intraoral imaging when using the size 1 and 0 matched collimation. Since the pediatric population is vulnerable to radiation exposure, any measurable reduction has a potential for long-term health benefits and is therefore clinically significant.

Stage-specific global alterations in the transcriptomes of Lyme disease spirochetes during tick feeding and following mammalian host adaptation.

Borrelia burgdorferi, the agent of Lyme disease, is maintained in nature within an enzootic cycle involving a mammalian reservoir and an Ixodes sp. tick vector. The transmission, survival and pathogenic potential of B. burgdorferi depend on the bacterium's ability to modulate its transcriptome as it transits between vector and reservoir host. Herein, we employed an amplification-microarray approach to define the B. burgdorferi transcriptomes in fed larvae, fed nymphs and in mammalian host-adapted organisms cultivated in dialysis membrane chambers. The results show clearly that spirochetes exhibit unique expression profiles during each tick stage and during cultivation within the mammal; importantly, none of these profiles resembles that exhibited by in vitro grown organisms. Profound shifts in transcript levels were observed for genes encoding known or predicted lipoproteins as well as proteins involved in nutrient uptake, carbon utilization and lipid synthesis. Stage-specific expression patterns of chemotaxis-associated genes also were noted, suggesting that the composition and interactivities of the chemotaxis machinery components vary considerably in the feeding tick and mammal. The results as a whole make clear that environmental sensing by B. burgdorferi directly or indirectly drives an extensive and tightly integrated modulation of cell envelope constituents, chemotaxis/motility machinery, intermediary metabolism and cellular physiology. These findings provide the necessary transcriptional framework for delineating B. burgdorferi regulatory pathways throughout the enzootic cycle as well as defining the contribution(s) of individual genes to spirochete survival in nature and virulence in humans.