Polarization memory effect in optical coherence tomography and dental imaging application.

We report the existence of polarization memory effect (PME) in optical coherence tomography and investigate its potential applications in dental imaging. We performed the study in three steps. First, microsphere scattering phantoms of different sizes were imaged in order to validate experimental results with PME theory.

Actinobacillus actinomycetemcomitans leukotoxin requires lipid microdomains for target cell cytotoxicity.

Actinobacillus actinomycetemcomitans produces a leukotoxin (Ltx) that kills leukocyte function-associated antigen-1 (LFA-1)-bearing cells from man, the Great Apes and Old World monkeys. The unique specificity of Ltx for the beta2 integrin, LFA-1, suggests it is capable of providing insight into the pathogenic mechanisms of Ltx and other RTX toxins. Using the Jurkat T cell line and an LFA-1-deficient Jurkat mutant (Jbeta2.

Cholesterol-rich membrane microdomains mediate cell cycle arrest induced by Actinobacillus actinomycetemcomitans cytolethal-distending toxin.

We have previously shown that Actinobacillus actinomycetemcomitans cytolethal-distending toxin (Cdt) is a potent immunosuppressive agent that induces G2/M arrest in human lymphocytes. In this study, we explored the possibility that Cdt-mediated immunotoxicity involves lipid membrane microdomains. We first determined that following treatment of Jurkat cells with Cdt holotoxin all three Cdt subunits localize to these microdomains.

Chondrocytes utilize a cholesterol-dependent lipid translocator to externalize phosphatidylserine.

During endochondral ossification, growth plate chondrocytes release plasma membrane (PM) derived matrix vesicles (MV), which are the site of initial hydroxyapatite crystal formation. MV constituents which facilitate the mineralization process include the integral membrane ectoenzymes alkaline phosphatase (ALPase) and nucleotide pyrophosphatase phosphodiesterase (NPP1/PC-1), along with a phosphatidylserine- (PS-) rich membrane surface that binds annexins and calcium, resulting in enhanced calcium entry into MV. In this study, we determined that chick growth plate MV were highly enriched in membrane raft microdomains containing high levels of cholesterol, glycophosphatidylinositol- (GPI-) anchored ALPase, and phosphatidylserine (PS) localized to the external leaflet of the bilayer.

E2F4 expression patterns in SIV encephalitis.

The E2F1 transcriptional regulator has been shown to exhibit altered expression and localization in HIVE and SIVE. However, other E2F family members are expressed in mature neurons and participate in neuronal differentiation. In an in vitro model of neuronal differentiation, E2F4 protein levels have been shown to increase.

Characterization of dentin, enamel, and carious lesions by a polarization-sensitive optical coherence tomography system.

Enamel and dentin are the primary components of human teeth. Both of them have a strong polarization effect. We designed a polarization-sensitive optical coherence tomography (PSOCT) system to study the spatially resolved scattering and polarization phenomena of teeth.

Assessing the accuracy of caries diagnosis via radiograph. Film versus print.

Background: The authors conducted this study to determine if proximal caries diagnoses made using bitewing radiographic images printed on photographic paper were comparable with diagnoses made using traditional radiographic film images.

Methods: The authors digitized 15 posterior bitewing radiographs that contained 74 carious and 127 sound unrestored proximal surfaces and printed them on photographic paper. Fourteen dentists evaluated the radiographs and two printed image formats (4 x 3 centimeters and 8 x 6 cm) for evidence of caries.

Quantifying enamel luster.

Objective: When the pH of the oral cavity drops below 5.5, the hydroxyapatite crystalline lattice is damaged and the tooth surface becomes rough. Consequently, specular reflection is decreased and results, clinically, in a loss of tooth luster.

Fetal Alz-50 clone 1 interacts with the human orthologue of the Kelch-like Ech-associated protein.

The fetal Alz-50 reactive clone 1 (FAC1) protein exhibits altered expression and subcellular localization during neuronal development and neurodegenerative diseases such as Alzheimer's disease. Using the yeast two-hybrid screen, the human orthologue of Keap1 (hKeap1) was identified as a FAC1 interacting protein. Keap1 is an important regulator of the oxidative stress response pathway through its interaction with the Nrf family of transcription factors.

Bone structure effect on root resorption.

Objectives: To explore if alveolar bone shape and density might promote external apical root resorption.

Setting And Sample Population: Panoramic radiographs of 700 patients who had orthodontic treatment at Temple University were reviewed and 22 patients with radiographic evidence of root resorption on the lower incisors were selected for the study. Exclusion criteria included a history of systemic diseases, craniofacial abnormalities, tooth injury, endodontically treated teeth, and impacted teeth.

Quantifying labial blood flow using optical Doppler tomography.

Objectives: Changes in the oral microvasculature occur in a variety of diseases. Optical Doppler tomography (ODT) combines laser Doppler flowmetry with optical coherence tomography (OCT) to produce high-resolution tomographic images of biological tissues that also detect the velocity and direction of blood flow. The objective of this study was to determine the feasibility of ODT to image labial blood flow.

Doppler angle and flow velocity mapping by combined Doppler shift and Doppler bandwidth measurements in optical Doppler tomography.

Accurate estimation of flow velocity requires measurement of Doppler angle, which is not available in general clinical applications. We describe a novel method of direct Doppler angle and flow velocity mapping that uses a conventional single-beam optical Doppler tomography system. The Doppler angle is estimated by combination of Doppler shift and Doppler bandwidth measurements, and flow velocity is calculated from the Doppler shift and the estimated Doppler angle.

Identification of occlusal sealants using optical coherence tomography.

Objective: Optical coherence tomography (OCT) is a new imaging technique that uses light to image dental structures interferometrically. OCT creates cross-sectional images that have potential diagnostic value for dental applications. When used in epidemiological studies, OCT offers a safe, non-invasive technique to discriminate occlusal sealants and composite restorations.

Quantitative assessment of flow velocity-estimation algorithms for optical Doppler tomography imaging.

We present a quantitative comparison of three categories of velocity estimation algorithms, including centroid techniques (the adaptive centroid technique and the weighted centroid technique), the sliding-window filtering technique, and correlation techniques (autocorrelation and cross correlation). We introduce, among these five algorithms, two new algorithms: weighted centroid and sliding-window filtering. Simulations and in vivo blood flow data are used to assess the velocity estimation accuracies of these algorithms.

Undiagnosed multiple myeloma causing extensive dental bleeding: report of a case and review.

A case of multiple myeloma causing profuse bleeding during a minor dental surgical procedure is presented. The value of dental radiography in detection of bone changes associated with an undiagnosed case of multiple myeloma is highlighted. We show that the extensive bleeding during the dental procedure could have been prevented if the panoramic radiograph had been evaluated carefully before initiation of the treatment.