Feasible and accurate occipitoatlantal transarticular fixation: an anatomic study.

Background: Defining the anatomic zones for the placement of occiput-C1 transarticular screws is essential for patient safety.

Objective: The feasibility and accuracy of occiput-C1 transarticular screw placement were evaluated in this anatomical study of normal cadaveric specimens.

Material And Methods: Sixteen measurements were determined for screw entry points, trajectories, and lengths for placement of transarticular screws, as applied in the technique described by Grob, on the craniovertebral junction segments (occiput-C2) of 16 fresh human cadaveric cervical spines and 41 computed tomographic reconstructions of the craniovertebral junction.

Biomechanics of a novel minimally invasive lumbar interspinous spacer: effects on kinematics, facet loads, and foramen height.

Objective: To study the alteration to normal biomechanics after insertion of a lumbar interspinous spacer (ISS) in vitro by nondestructive cadaveric flexibility testing.

Methods: Seven human cadaveric specimens were studied before and after ISS placement at L1-L2. Angular range of motion, lax zone, stiff zone, sagittal instantaneous axis of rotation (IAR), foraminal height, and facet loads were compared between conditions.

Dynamic lumbar pedicle screw-rod stabilization: in vitro biomechanical comparison with standard rigid pedicle screw-rod stabilization.

Object: It is unclear how the biomechanics of dynamic posterior lumbar stabilization systems and traditional rigid pedicle screw-rod systems differ. This study examined the biomechanical response of a hinged-dynamic pedicle screw compared with a standard rigid screw used in a 1-level pedicle screw-rod construct.

Methods: Unembalmed human cadaveric L3-S1 segments were tested intact, after L4-5 discectomy, after rigid pedicle screw-rod fixation, and after dynamic pedicle screw-rod fixation.

Nitrate signaling: adaptation to fluctuating environments.

Nitrate (NO(3)(-)) is a key nutrient as well as a signaling molecule that impacts both metabolism and development of plants. Understanding the complexity of the regulatory networks that control nitrate uptake, metabolism, and associated responses has the potential to provide solutions that address the major issues of nitrate pollution and toxicity that threaten agricultural and ecological sustainability and human health. Recently, major advances have been made in cataloguing the nitrate transcriptome and in identifying key components that mediate nitrate signaling.

In vitro biomechanical analysis of a new lumbar low-profile locking screw-plate construct versus a standard top-loading cantilevered pedicle screw-rod construct: technical report.

Objective: A standard top-loading lumbar pedicle screw-rod system is compared with a pedicle screw-plate system with smaller-diameter screws, more medial entry, and lower profile to assess the relative stability, strength, and resistance to fatigue of the 2 systems.

Methods: Seven human cadaveric specimens were studied with each surgical construct. Nondestructive, nonconstraining pure moments were applied to specimens to induce flexion, extension, lateral bending, and axial rotation while recording L5-S1 motion optoelectronically.

The Arabidopsis Prohibitin Gene PHB3 Functions in Nitric Oxide-Mediated Responses and in Hydrogen Peroxide-Induced Nitric Oxide Accumulation.

To discover genes involved in nitric oxide (NO) metabolism, a genetic screen was employed to identify mutants defective in NO accumulation after treatment with the physiological inducer hydrogen peroxide. In wild-type Arabidopsis thaliana plants, NO levels increase eightfold in roots after H(2)O(2) treatment for 30 min. A mutant defective in H(2)O(2)-induced NO accumulation was identified, and the corresponding mutation was mapped to the prohibitin gene PHB3, converting the highly conserved Gly-37 to an Asp in the protein's SPFH domain.

Social disparities in periodontitis among US adults: the effect of allostatic load.

Background: Periodontitis has been shown to be associated with allostatic load, a measure of physiological instability across biological systems from cumulative or repeated adaptation to stressors. Minority racial/ethnic and low socioeconomic groups tend to have higher prevalence of periodontitis and are more likely to be exposed to stress. The association between periodontitis and allostatic load and whether this association differed by race/ethnicity, education, income and age among US adults were examined.

Physical properties of conventional and Super Slick elastomeric ligatures after intraoral use.

Objective: To investigate the change in the physical properties of conventional and Super Slick elastomeric ligatures after they have been in the mouth.

Materials And Methods: Nine healthy volunteers took part. One orthodontic bracket was bonded to a premolar tooth in each of the four quadrants of the mouth.

Survivors of childhood cancer: an Australian audit of vaccination status after treatment.

Background: Survivors of childhood and adolescent cancer are at risk of vaccine preventable diseases and are recommended to receive booster vaccinations post-chemotherapy. The aim of this study was to describe the compliance of post-chemotherapy revaccination of childhood cancer survivors relative to current Australian guidelines.

Procedures: A multi-faceted retrospective review of childhood cancer survivors at the Royal Children's Hospital, Melbourne, Australia was undertaken.

Biomechanical effects of laminoplasty versus laminectomy: stenosis and stability.

Study Design: In vitro human cadaveric study simultaneously quantifying sagittal plane flexibility and spinal canal stenosis.

Objective: To compare biomechanical stability and the change in cross-sectional area during flexion and extension after laminectomy and open-door laminoplasty.

Summary Of Background Data: Spinal canal stenosis has been quantified in vitro but has not been quantified in studies of laminectomy or laminoplasty.

Biomechanics of C-7 transfacet screw fixation.

Object: The small diameter of the pedicle can make C-7 pedicle screw insertion dangerous. Although transfacet screws have been studied biomechanically when used in pinning joints, they have not been well studied when used as part of a C7-T1 screw/rod construct. The authors therefore compared C7-T1 fixation using a C-7 transfacet screw/T-1 pedicle screw construct with a construct composed of pedicle screws at both levels.

Self-reported diabetes in Hispanic subgroup, non-Hispanic black, and non-Hispanic white populations: National Health Interview Survey, 1997-2005.

Objectives: We estimated the prevalence of self-reported diabetes in Hispanic subgroup (Puerto Rican, Mexican, Mexican American, Cuban, Dominican, Central and South American, and other Hispanic), non-Hispanic black, and non-Hispanic white populations aged 20 years and older.

Methods: Using the National Health Interview Survey 1997-2005, we limited these analyses to 272,041 records of adults aged 20 years and older, including 46,749 records for Hispanic respondents. We used logistic regression to assess the strength of the association between race/ethnicity and self-reported diabetes before and after adjusting for selected characteristics.

Immunisation practices in infants born prematurely: neonatologists' survey and clinical audit.

Aim: To determine Australian neonatologists' recommendations for the immunisation of ex-preterm infants and compare their actual immunisation status with recommended Australian guidelines.

Methods: A self-administered nine-part questionnaire of current immunisation practices was sent to all Neonatologists in Australia (2006). A complementary retrospective immunisation audit was conducted in two tertiary neonatal units in Melbourne.

History of cervical disc arthroplasty.

Enthusiasm for cervical disc arthroplasty is based on the premise that motion-preserving devices attenuate the progression of adjacent-segment disease (ASD) in the cervical spine. Arthrodesis, on the other hand, results in abnormal load transfer on adjacent segments, leading to the acceleration of ASD. It has taken several decades of pioneering work to produce clinically relevant devices that mimic the kinematics of the intervertebral disc.

A genetic screen for nitrate regulatory mutants captures the nitrate transporter gene NRT1.1.

Nitrate regulatory mutants (nrg) of Arabidopsis (Arabidopsis thaliana) were sought using a genetic screen that employed a nitrate-inducible promoter fused to the yellow fluorescent protein marker gene YFP. A mutation was identified that impaired nitrate induction, and it was localized to the nitrate regulatory gene NLP7, demonstrating the validity of this screen. A second, independent mutation (nrg1) mapped to a region containing the NRT1.

Racial/ethnic disparities in obesity among US-born and foreign-born adults by sex and education.

This study examines sex and education variations in obesity among US- and foreign-born whites, blacks, and Hispanics utilizing 1997-2005 data from the National Health Interview Survey on 267,585 adults aged > or =18 years. After adjusting for various demographic, health, and socioeconomic factors via logistic regression, foreign-born black men had the lowest odds for obesity relative to US-born white men. The largest racial/ethnic disparity in obesity was between US-born black and white women.

Polymicrogyria in standard poodles.

Background: Polymicrogyria is a disorder of cerebrocortical migration resulting in increased numbers of small, disorganized gyri. This disorder occurs in Standard Poodles and in cattle.

Objectives: To describe the clinical, electroencephalographic, imaging, and histopathologic features in poodles with polymicrogyria.

Procaspase 8 overexpression in non-small-cell lung cancer promotes apoptosis induced by FLIP silencing.

We found that procaspase 8 was overexpressed in non-small-cell lung cancers (NSCLCs) compared with matched normal tissues. The caspase 8 inhibitor FLICE-inhibitory protein (FLIP) was also overexpressed in the majority of NSCLCs. Silencing FLIP induced caspase 8 activation and apoptosis in NSCLC cell lines, but not in normal lung cell lines.

Evaluation of pulsed high intensity focused ultrasound exposures on metastasis in a murine model.

High intensity focused ultrasound (HIFU) may be employed in two ways: continuous exposures for thermal ablation of tissue (> 60 degrees C), and pulsed-exposures for non-ablative effects, including low temperature hyperthermia (37-45 degrees C), and non thermal effects (e.g. acoustic cavitation and radiation forces).

What is your diagnosis? Shoulder mass in a dog with lameness.

An adult castrated male Golden Retriever of unknown age was presented with a history of weight loss and progressive left thoracic limb lameness. On physical examination, a solid mass was palpated on the left scapula that had areas of lysis on radiographs and an area of cortical bone loss on ultrasound. Hepatomegaly, abdominal distension, and numerous intra-abdominal soft tissue masses were also found.

Trajectory analysis and pullout strength of self-centering lumbar pedicle screws.

Object: An experiment was performed to study the limits of the ability of screws designed to center themselves in the pedicle during insertion, and to study whether straight-ahead versus inward screw insertion trajectories differ in their resistance to pullout.

Methods: Forty-nine human cadaveric lumbar vertebrae were studied. Pedicle screws were inserted in trajectories starting 0 degrees, 10 degrees, 20 degrees, or 30 degrees from the optimal trajectory, either medially or laterally misdirected.

Small tin cluster anions: transition from quasispherical to prolate structures.

The structures and energetics of small tin cluster Sn(n)(-) anions up to n=15 were determined by a combination of density-functional theory and three different experimental methods: Ion mobility spectrometry, trapped ion electron diffraction, and collision induced dissociation. We find compact, quasispherical structures up to n=12. Sn(12)(-) is a slightly distorted hollow icosahedron while Sn(13)(-) to Sn(15)(-) have prolate structures, consisting of merged, hollow, in part incomplete, deltahedral subunits: Sn(13)(-) consists of a face-sharing pentagonal bipyramid and tricapped trigonal bipyramid, Sn(14)(-) comprises a face-sharing dicapped trigonal prism and capped square-antiprism, and Sn(15)(-) consists of two face-sharing tricapped trigonal prisms.

Atlantoaxial rotatory subluxation with ligamentous disruption: a biomechanical comparison of current fusion methods.

Objective: We evaluated the biomechanical effects of 4 instrumented configurations after induced atlantoaxial rotatory subluxation: transarticular screw fixation (T/A) and polyaxial C1 lateral mass and C2 pedicle screw and rod fixation (LC1-PC2) for atlantoaxial arthrodesis with unilateral and bilateral instrumentation.

Methods: Three-dimensional intervertebral motion was tracked stereophotogrammetrically while 14 human cadaveric spine specimens underwent nonconstraining pure moment loading. Nondestructive loads were applied quasi-statistically in 0.