Reliability of 3D dental and skeletal landmarks on CBCT images.

OBJECTIVES: To quantify reliability of three-dimensional skeletal landmarks and a comprehensive set of dental landmarks in cone-beam computed tomography (CBCT) and to determine the shapes of envelope of error. MATERIALS AND METHODS: Three judges located 31 skeletal landmarks and 60 dental landmarks on the pre- and posttreatment CBCT images of 22 patients. Landmark error was determined by calculating the distance of deviation of landmark locations around their average. Standard deviation and mean radial spherical error were calculated. Scatterplots were constructed to characterize envelope of error. RESULTS: The midline landmarks of the cranial base were highly reliable. Bilateral skeletal landmarks tended to have larger error than midline landmarks. Among the nonconventional landmarks, fronto-zygomatic suture, condyle, and mental foramen showed relatively high reliability. However, foramen spinosum and temporal fossa showed larger errors. Gonion was the least reliable landmark. Most dental landmarks were located more reliably than skeletal landmarks. The highest reliability was found at incisal edges. Mesiobuccal cusp of first molars also showed high reliability. CONCLUSIONS: There were differences in the size and shape of the distributions of errors of different landmarks. Most landmarks showed elongated envelopes. Bilateral structures tended to show greater errors than midline structures. Most dental landmarks were more reliable than skeletal landmarks.

A HIF-LIMD1 negative feedback mechanism mitigates the pro-tumorigenic effects of hypoxia.

The adaptive cellular response to low oxygen tensions is mediated by the hypoxia-inducible factors (HIFs), a family of heterodimeric transcription factors composed of HIF-α and HIF-ß subunits. Prolonged HIF expression is a key contributor to cellular transformation, tumorigenesis and metastasis. As such, HIF degradation under hypoxic conditions is an essential homeostatic and tumour-suppressive mechanism. LIMD1 complexes with PHD2 and VHL in physiological oxygen levels (normoxia) to facilitate proteasomal degradation of the HIF-α subunit. Here, we identify LIMD1 as a HIF-1 target gene, which mediates a previously uncharacterised, negative regulatory feedback mechanism for hypoxic HIF-α degradation by modulating PHD2-LIMD1-VHL complex formation. Hypoxic induction of LIMD1 expression results in increased HIF-α protein degradation, inhibiting HIF-1 target gene expression, tumour growth and vascularisation. Furthermore, we report that copy number variation at the LIMD1 locus occurs in 47.1% of lung adenocarcinoma patients, correlates with enhanced expression of a HIF target gene signature and is a negative prognostic indicator. Taken together, our data open a new field of research into the aetiology, diagnosis and prognosis of LIMD1-negative lung cancers.

Institution of Military Working Dog Physical Profile Record to Clarify Medical Readiness Category Status.

The current medical readiness category (CAT) status system used for military working dogs (MWDs) simply outlines the deployability of an MWD. This system, however, does not detail any other restrictions or the reason for assigning the current CAT status. The question is often raised as to whether the MWD can continue to work and perform everyday duties despite not being a CAT I. Using the Physical Profile Record system established for human providers, a system was adapted for MWDs. This system will allow Veterinary Corps Officers to give specific instructions to the handler and owning unit about the nature, progression, and details of injury or dysfunction beyond the CAT status. Furthermore, the ability to track chronic conditions and duration of illness will increase overall readiness of a kennel.

American Association of Orthodontists Foundation Craniofacial Growth Legacy Collection: Overview of a powerful tool for orthodontic research and teaching.

This article reports on the current status of the American Association of Orthodontists Foundation (AAOF) Craniofacial Growth Legacy Collection--an AAOF-supported multi-institutional project that uses the Internet and cloud computing to collect and share craniofacial images and data for orthodontic research and education. The project gives investigators and clinicians all over the world online access to longitudinal information on craniofacial development in untreated children with malocclusions of various types. It also is a unique source of control samples for testing the validity of consensually accepted beliefs about the effects of orthodontic treatment or of failure to treat.

How Frequently are "Classic" Drug-Seeking Behaviors Used by Drug-Seeking Patients in the Emergency Department?

INTRODUCTION: Drug-seeking behavior (DSB) in the emergency department (ED) is a very common problem, yet there has been little quantitative study to date of such behavior. The goal of this study was to assess the frequency with which drug seeking patients in the ED use classic drug seeking behaviors to obtain prescription medication. METHODS: We performed a retrospective chart review on patients in an ED case management program for DSB. We reviewed all visits by patients in the program that occurred during a 1-year period, and recorded the frequency of the following behaviors: complaining of headache, complaining of back pain, complaining of dental pain, requesting medication by name, requesting a refill of medication, reporting medications as having been lost or stolen, reporting 10/10 pain, reporting greater than 10/10 pain, reporting being out of medication, and requesting medication parenterally. These behaviors were chosen because they are described as "classic" for DSB in the existing literature. RESULTS: We studied 178 patients from the case management program, who made 2,486 visits in 1 year. The frequency of each behavior was: headache 21.7%, back pain 20.8%, dental pain 1.8%, medication by name 15.2%, requesting refill 7.0%, lost or stolen medication 0.6%, pain 10/10 29.1%, pain greater than 10/10 1.8%, out of medication 9.5%, and requesting parenteral medication 4.3%. Patients averaged 1.1 behaviors per visit. CONCLUSION: Drug-seeking patients appear to exhibit "classically" described drug-seeking behaviors with only low to moderate frequency. Reliance on historical features may be inadequate when trying to assess whether or not a patient is drug-seeking.

Effect of cephalometer misalignment on calculations of facial asymmetry.

INTRODUCTION: In this study, we evaluated errors introduced into the interpretation of facial asymmetry on posteroanterior (PA) cephalograms due to malpositioning of the x-ray emitter focal spot. We tested the hypothesis that horizontal displacements of the emitter from its ideal position would produce systematic displacements of skull landmarks that could be fully accounted for by the rules of projective geometry alone. METHODS: A representative dry skull with 22 metal markers was used to generate a series of PA images from different emitter positions by using a fully calibrated stereo cephalometer. Empirical measurements of the resulting cephalograms were compared with mathematical predictions based solely on geometric rules. The empirical measurements matched the mathematical predictions within the limits of measurement error (x= 0.23 mm), thus supporting the hypothesis. Based upon this finding, we generated a completely symmetrical mathematical skull and calculated the expected errors for focal spots of several different magnitudes. Quantitative data were computed for focal spot displacements of different magnitudes. RESULTS AND CONCLUSIONS: Misalignment of the x-ray emitter focal spot introduces systematic errors into the interpretation of facial asymmetry on PA cephalograms. For misalignments of less than 20 mm, the effect is small in individual cases. However, misalignments as small as 10 mm can introduce spurious statistical findings of significant asymmetry when mean values for large groups of PA images are evaluated.

Centromedullary pinning of radial neck fractures: length matters!

Centromedullary pinning provides an excellent alternative to open reduction in severely displaced radial neck fractures. It has a low complication rate because it is an extra-articular and minimally invasive technique. The functional results have been shown to be good or excellent in most cases. The technique is described clearly in the literature but has posed us with certain difficulties. We present a useful technical tip on performing centromedullary pinning based on our experience of treating radial neck fractures by this method.

Joint arthroplasty, dental treatment, and antibiotics: a review.

Many patients with artificial joints seek guidance from their dental and orthopaedic surgeons on whether they should take prophylactic antibiotics for routine dental treatment. Advice on this has been conflicting in the past, and other than a joint statement from the American Academy of Orthopaedic Surgeons and the American Dental Association, there has been little official guidance. In view of the lack of consensus, we have reviewed the relevant literature and have concluded that antibiotic prophylaxis should not be routinely given to all patients undergoing dental treatment but should be reserved for those patients deemed at high risk.