Sodium fluoride and silver diamine fluoride-coated tooth surfaces inhibit bacterial acid production at the bacteria/tooth interface.

OBJECTIVES: This study aimed to evaluate whether coating tooth surfaces with sodium fluoride (NaF) or silver diamine fluoride (SDF) inhibits bacteria-induced pH reductions at the bacteria/tooth interface. METHODS: Specimens of coronal enamel (CE) or root dentin (RD) were prepared. The surfaces of the specimens were treated with 2% NaF or 38% SDF solution. Some specimens were aged for 1 week after being treated. A tooth specimen was fixed to the bottom of the well of the experimental apparatus. A miniature pH electrode was placed on the specimen and the well was filled with Streptococcus mutans (SM) cells. The pH was monitored after the addition of 0.5% glucose. SM cells were recovered from the wells, and the amounts of lactate, calcium, fluoride, and silver were measured. RESULTS: The fluoride-treated tooth specimens exhibited significantly higher pH values than the untreated controls, irrespective of the tooth substrate at 120 min (CE: NaF 4.62 ± 0.06 vs 4.34 ± 0.10 and SDF 5.23 ± 0.29 vs 4.44 ± 0.16, RD: NaF 5.10 ± 0.11 vs 4.54 ± 0.33 and SDF 6.65 ± 0.47 vs 4.64 ± 0.39). The SDF-coated RD specimens released the greatest amounts of fluoride (103.3 ± 48.1 nmol/well) and silver (70.4 ± 36.9 nmol/well), while they exhibited significantly lower lactate production and decalcification (calcium release) than the control samples (lactate: 4.0 ± 0.7 vs 7.4 ± 0.3 mmol/l, calcium: 2.2 ± 0.4 vs 3.7 ± 0.5 µg/ml). This antimicrobial effect was weakened by 1 week's aging, while the acid resistance of the fluoride-treated surfaces seemed to increase with aging. CONCLUSIONS: Fluoride-treated tooth surfaces inhibit bacterial acid production at the bacteria/tooth interface. The SDF-coated RD had the strongest inhibitory effect. CLINICAL SIGNIFICANCE: Coating RD with SDF could help to prevent root caries.

Tip-cell behavior is regulated by transcription factor FoxO1 under hypoxic conditions in developing mouse retinas.

Forkhead box protein O1 (FoxO1) is a transcription factor and a critical regulator of angiogenesis. Various environmental stimuli, including growth factors, nutrients, shear stress, oxidative stress and hypoxia, affect FoxO1 subcellular localization and strongly influence its transcriptional activity; however, FoxO1-localization patterns in endothelial cells (ECs) during development have not been clarified in vivo. Here, we reported that FoxO1 expression was observed in three layers of angiogenic vessels in developing mouse retinas and that among these layers, the front layer showed high levels of FoxO1 expression in the nuclei of most tip ECs. Because tip ECs migrate toward the avascular hypoxic area, we focused on hypoxia as a major stimulus regulating FoxO1 subcellular localization in tip cells. In cultured ECs, FoxO1 accumulated into the nucleus under hypoxic conditions, with hypoxia also inducing expression of tip-cell-specific genes, including endothelial-specific molecule 1 (ESM1), which was suppressed by FoxO1 knockdown. Additionally, in murine models, EC-specific FoxO1 deletion resulted in reduced ESM1 expression and suppressed tip-cell migration during angiogenesis. These findings indicated roles for FoxO1 in tip-cell migration and that its transcriptional activity is regulated by hypoxia.

World's first magnetic resonance imaging/x-ray/operating room suite: a significant milestone in the improvement of neurosurgical diagnosis and treatment.

OBJECT: In February 2006, the magnetic resonance/x-ray/operating room (MRXO) suite opened at the authors' institution. This is the first hybrid neurosurgical procedure suite to combine magnetic resonance (MR) imaging, computed tomography (CT), and angiography within a neurosurgical operating room (OR). In the present paper the authors describe the concept of the MRXO as well as their first 10 months of experience using this suite, and discuss its advantages and limitations. METHODS: In the MRXO suite, the combined OR and angiography (OR-angiography) station is located in the middle of the suite, and the MR imaging and CT scanning stations are each installed in an adjoining bay connected to the OR-angiography station by shielded sliding doors. The surgical, MR imaging, angiography, and CT tables are positioned in order of use. The patient lies on a fully MR imaging- and radiography-compatible mobile patient tabletop that is used to move the patient quickly and safely among the tables in the imaging and operating components of the MRXO suite. RESULTS: The authors performed all interventional procedures safely. The specially designed operating tabletop of the MRXO suite reduced the limitations on neurosurgeons during standard neurosurgical procedures. This hybrid suite helps to provide high-quality intraoperative imaging, greatly reducing the risk of unexpected events during the procedure. CONCLUSIONS: The MRXO suite, which combines OR and imaging equipment, represents a significant milestone in the improvement of neurosurgical diagnosis and treatment and other interventional procedures. Another advantage of the MRXO suite is its cost-effectiveness, which is partly due to its streamlined imaging procedure.