Hypothermia inhibits osteoblast differentiation and bone formation but stimulates osteoclastogenesis.

It has long been known that core body temperature declines with age, with temperatures of 35.5°C or below common in the elderly. However, the effects of temperature reduction on bone cell function and skeletal homeostasis have been little studied.

Comparison of k-t SENSE/k-t BLAST with conventional SENSE applied to BOLD fMRI.

Purpose: To compare k-t BLAST (broad-use linear-acquisition speedup technique)/k-t SENSE (sensitivity encoding) with conventional SENSE applied to a simple fMRI paradigm.

Materials And Methods: Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was performed at 3 T using a displaced ultra-fast low-angle refocused echo (UFLARE) pulse sequence with a visual stimulus in a block paradigm. Conventional SENSE and k-t BLAST/k-t SENSE data were acquired.

Hypoxia stimulates osteoclast formation from human peripheral blood.

Active pathological bone destruction in humans often occurs in locations where oxygen tension (pO(2)) is likely to be low, for example, at the sites of tumours, inflammation, infections and fractures, or the poorly vascularized yellow fatty marrow of the elderly. We examined the effect of pO(2) on formation of osteoclasts, the cells responsible for bone resorption, in 14-day cultures of normal human peripheral blood mononuclear cells (hPBMCs) on ivory discs. Hypoxia (1-2% O(2)) caused threefold increases in the number of osteoclasts formed, compared with 20% O(2).

Comparison of left ventricular function assessment using phonocardiogram- and electrocardiogram-triggered 2D SSFP CINE MR imaging at 1.5 T and 3.0 T.

Objective: As high-field cardiac MRI (CMR) becomes more widespread the propensity of ECG to interference from electromagnetic fields (EMF) and to magneto-hydrodynamic (MHD) effects increases and with it the motivation for a CMR triggering alternative. This study explores the suitability of acoustic cardiac triggering (ACT) for left ventricular (LV) function assessment in healthy subjects (n = 14).

Methods: Quantitative analysis of 2D CINE steady-state free precession (SSFP) images was conducted to compare ACT's performance with vector ECG (VCG).

Feasibility of cardiac gating free of interference with electro-magnetic fields at 1.5 Tesla, 3.0 Tesla and 7.0 Tesla using an MR-stethoscope.

Objectives: To circumvent the challenges of conventional electrocardiographic (ECG)-gating by examining the efficacy of an MR stethoscope, which offers (i) no risk of high voltage induction or patient burns, (ii) immunity to electromagnetic interference, (iii) suitability for all magnetic field strengths, and (iv) patient comfort together with ease of use for the pursuit of reliable and safe (ultra)high field cardiac gated magnetic resonance imaging (MRI).

Materials And Methods: The acoustic gating device consists of 3 main components: an acoustic sensor, a signal processing unit, and a coupler unit to the MRI system. Signal conditioning and conversion are conducted outside the 0.

Feasibility of k-t BLAST for BOLD fMRI with a spin-echo based acquisition at 3 T and 7 T.

Objectives: This study tested the feasibility of applying k-t BLAST to blood oxygen level dependent functional MRI of the brain at 3 Tesla (T) and at 7 T. Shorter echo train lengths, achieved through the application of k-t BLAST, are expected to counteract increased sensitivity to inhomogeneities in B0 at higher magnetic field strengths, especially in echo planar images, and reduce the relatively long acquisition times and high RF power deposition in spin-echo based methods.

Materials And Methods: k-t BLAST was combined with displaced UFLARE at 3 T and 7 T.

Myocardial T2* mapping free of distortion using susceptibility-weighted fast spin-echo imaging: a feasibility study at 1.5 T and 3.0 T.

This study demonstrates the feasibility of applying free-breathing, cardiac-gated, susceptibility-weighted fast spin-echo imaging together with black blood preparation and navigator-gated respiratory motion compensation for anatomically accurate T2* mapping of the heart. First, T2* maps are presented for oil phantoms without and with respiratory motion emulation T2* = (22.1 +/- 1.

Hypoxia stimulates vesicular ATP release from rat osteoblasts.

Many neuronal and non-neuronal cell types release ATP in a controlled manner. After release, extracellular ATP (or, following hydrolysis, ADP) acts on cells in a paracrine manner via P2 receptors. Extracellular nucleotides are now thought to play an important role in the regulation of bone cell function.

Extracellular nucleotides block bone mineralization in vitro: evidence for dual inhibitory mechanisms involving both P2Y2 receptors and pyrophosphate.

Extracellular nucleotides, signaling through P2 receptors, may act as local regulators of bone cell function. We investigated the effects of nucleotide agonists [ATP, ADP, uridine triphosphate (UTP), and uridine diphosphate] and pyrophosphate (PPi, a key physiological inhibitor of mineralization) on the deposition and mineralization of collagenous matrix by primary osteoblasts derived from rat calvariae. Our results show that extracellular ATP, UTP, and PPi strongly and selectively blocked the mineralization of matrix nodules; ADP and uridine diphosphate were without effect.

A simple, reproducible method for monitoring the treatment of tumours using dynamic contrast-enhanced MR imaging.

Dynamic contrast-enhanced MR imaging (DCE-MRI) may act as a biomarker for successful cancer therapy. Simple, reproducible techniques may widen this application. This paper demonstrates a single slice imaging technique.

Hypoxia inhibits the growth, differentiation and bone-forming capacity of rat osteoblasts.

We investigated the effect of hypoxia on rat osteoblast function in long-term primary cultures. Reduction of pO2 from 20% to 5% and 2% decreased formation of mineralized bone nodules 1.7-fold and 11-fold, respectively.

Wnt signalling in osteoblasts regulates expression of the receptor activator of NFkappaB ligand and inhibits osteoclastogenesis in vitro.

Reports implicating Wnt signalling in the regulation of bone mass have prompted widespread interest in the use of Wnt mimetics for the treatment of skeletal disorders. To date much of this work has focused on their anabolic effects acting on cells of the osteoblast lineage. In this study we provide evidence that Wnts also regulate osteoclast formation and bone resorption, through a mechanism involving transcriptional repression of the gene encoding the osteoclastogenic cytokine receptor activator of NFkappaB ligand (RANKL or TNFSF11) expressed by osteoblasts.

Understanding and optimizing the amplitude modulated control for multiple-slice continuous arterial spin labeling.

Multiple-slice perfusion imaging by continuous arterial spin labeling (CASL) is made possible by amplitude modulation (AM) of the labeling RF pulse, but perfusion sensitivity is reduced relative to the single-slice technique. A computer model of the Bloch equations for velocity driven adiabatic fast passage was developed to elucidate the compromised sensitivity to perfusion of the AM control technique for CASL. Calculations were performed over ranges of RF pulse amplitude, B1; magnetic field gradient, G; phase, phi, and frequency, f, of the modulation function; velocity, v, and relaxation times, T1 and T2, of blood.

Acidosis inhibits bone formation by osteoblasts in vitro by preventing mineralization.

The negative effect of acidosis on the skeleton has been known for almost a century. Bone mineral serves an important pathophysiologic role as a reserve of hydroxyl ions to buffer systemic protons if the kidneys and lungs are unable to maintain acid-base balance within narrow physiologic limits. Extracellular hydrogen ions are now thought to be the primary activation signal for osteoclastic bone resorption, and osteoclasts are very sensitive to small changes in pH within the pathophysiologic range.

Hypoxia is a major stimulator of osteoclast formation and bone resorption.

Hypoxia is known to act as a general stimulator of cells derived from marrow precursors. We investigated the effect of oxygen tension on the formation and function of osteoclasts, the cells responsible for bore resorption, which are of promonocytic origin. Using 7- and 13-day cultures of mouse marrow cells on ivory discs, we found that reducing oxygen tension from the ambient atmospheric level of 20% by increasing the proportion of nitrogen caused progressive increases in the formation of multinucleated osteoclasts and resorption pits.

Velocity-driven adiabatic fast passage for arterial spin labeling: results from a computer model.

Velocity-driven adiabatic fast passage (AFP) is commonly employed for perfusion imaging by continuous arterial spin labeling (CASL). The degree of inversion of protons in blood determines the sensitivity of CASL to perfusion. For this study, a computer model of the modified Bloch equations was developed to establish the optimum conditions for velocity-driven AFP.

Manual handling and nursing children.

The aim of this article is to highlight some of the unique challenges relating to handling children, such as: their stage of physical and cognitive development, their position in relation to the carer's centre of gravity, their level of comprehension and their ability to communicate.

A filter for breast imaging on a radiotherapy X-ray simulator.

Simulator radiographs taken as a record of breast radiotherapy planning often show ill defined breast tissue margins because exposure parameters are set to optimize visualization of the chest wall rather than the bulk of the breast. This creates difficulties when using simulator images as reference images in verification by comparing with either portal film or images from an electronic portal imaging device. Our aim was to improve breast images taken at simulation without changing exposure parameters that have been optimized for visualization of the chest wall.

Measurement of cardiac output in standing horses by Doppler echocardiography and thermodilution.

Measurement of cardiac output by Doppler echocardiography were compared to simultaneous measurements by thermodilution in 9 conscious horses. In the Doppler technique, mean blood flow velocities for estimation of cardiac output were recorded from the aorta and pulmonary artery. The flow area of each vessel was calculated from the vessel diameter, measured from a 2-dimensional ultrasound image.