Mechanically activated mesenchymal-derived bone cells drive vessel formation via an extracellular vesicle mediated mechanism.

Blood vessel formation is an important initial step for bone formation during development as well as during remodelling and repair in the adult skeleton. This results in a heavily vascularized tissue where endothelial cells and skeletal cells are constantly in crosstalk to facilitate homeostasis, a process that is mediated by numerous environmental signals, including mechanical loading. Breakdown in this communication can lead to disease and/or poor fracture repair. Therefore, this study aimed to determine the role of mature bone cells in regulating angiogenesis, how this is influenced by a dynamic mechanical environment, and understand the mechanism by which this could occur. Herein, we demonstrate that both osteoblasts and osteocytes coordinate endothelial cell proliferation, migration, and blood vessel formation via a mechanically dependent paracrine mechanism. Moreover, we identified that this process is mediated via the secretion of extracellular vesicles (EVs), as isolated EVs from mechanically stimulated bone cells elicited the same response as seen with the full secretome, while the EV-depleted secretome did not elicit any effect. Despite mechanically activated bone cell-derived EVs (MA-EVs) driving a similar response to VEGF treatment, MA-EVs contain minimal quantities of this angiogenic factor. Lastly, a miRNA screen identified mechanoresponsive miRNAs packaged within MA-EVs which are linked with angiogenesis. Taken together, this study has highlighted an important mechanism in osteogenic-angiogenic coupling in bone and has identified the mechanically activated bone cell-derived EVs as a therapeutic to promote angiogenesis and potentially bone repair.

Design of a multi-detector, single line-of-sight, time-of-flight system to measure time-resolved neutron energy spectra.

In the dynamic environment of burning, thermonuclear deuterium-tritium plasmas, diagnosing the time-resolved neutron energy spectrum is of critical importance. Strategies exist for this diagnosis in magnetic confinement fusion plasmas, which presently have a lifetime of ∼1012 longer than inertial confinement fusion (ICF) plasmas. Here, we present a novel concept for a simple, precise, and scale-able diagnostic to measure time-resolved neutron spectra in ICF plasmas. The concept leverages general tomographic reconstruction techniques adapted to time-of-flight parameter space, and then employs an updated Monte Carlo algorithm and National Ignition Facility-relevant constraints to reconstruct the time-evolving neutron energy spectrum. Reconstructed spectra of the primary 14.028 MeV nDT peak are in good agreement with the exact synthetic spectra. The technique is also used to reconstruct the time-evolving downscattered spectrum, although the present implementation shows significantly more error.

Beam-Target Helicity Asymmetry for γ[over →]n[over →]→π

We report the first beam-target double-polarization asymmetries in the γ+n(p)→π^{-}+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN^{*} resonance photocouplings.

X-ray bang-time and fusion reaction history at picosecond resolution using RadOptic detection.

We report recent progress in the development of RadOptic detectors, radiation to optical converters, that rely upon x-ray absorption induced modulation of the optical refractive index of a semiconductor sensor medium to amplitude modulate an optical probe beam. The sensor temporal response is determined by the dynamics of the electron-hole pair creation and subsequent relaxation in the sensor medium. Response times of a few ps have been demonstrated in a series of experiments conducted at the LLNL Jupiter Laser Facility (JLF). This technology will enable x-ray bang-time and fusion burn-history measurements with ∼ ps resolution.

Molecular phylogeny and character evolution in terete-stemmed Andean opuntias (Cactaceae-Opuntioideae).

The cacti of tribe Tephrocacteae (Cactaceae-Opuntioideae) are adapted to diverse climatic conditions over a wide area of the southern Andes and adjacent lowlands. They exhibit a range of life forms from geophytes and cushion-plants to dwarf shrubs, shrubs or small trees. To confirm or challenge previous morphology-based classifications and molecular phylogenies, we sampled DNA sequences from the chloroplast trnK/matK region and the nuclear low copy gene phyC and compared the resulting phylogenies with previous data gathered from nuclear ribosomal DNA sequences. The here presented chloroplast and nuclear low copy gene phylogenies were mutually congruent and broadly coincident with the classification based on gross morphology and seed micro-morphology and anatomy. Reconstruction of hypothetical ancestral character states suggested that geophytes and cushion-forming species probably evolved several times from dwarf shrubby precursors. We also traced an increase of embryo size at the expense of the nucellus-derived storage tissue during the evolution of the Tephrocacteae, which is thought to be an evolutionary advantage because nutrients are then more rapidly accessible for the germinating embryo. In contrast to these highly concordant phylogenies, nuclear ribosomal DNA data sampled by a previous study yielded conflicting phylogenetic signals. Secondary structure predictions of ribosomal transcribed spacers suggested that this phylogeny is strongly influenced by the inclusion of paralogous sequence probably arisen by genome duplication during the evolution of this plant group.

Widespread mRNA association with cytoskeletal motor proteins and identification and dynamics of myosin-associated mRNAs in S. cerevisiae.

Programmed mRNA localization to specific subcellular compartments for localized translation is a fundamental mechanism of post-transcriptional regulation that affects many, and possibly all, mRNAs in eukaryotes. We describe here a systematic approach to identify the RNA cargoes associated with the cytoskeletal motor proteins of Saccharomyces cerevisiae in combination with live-cell 3D super-localization microscopy of endogenously tagged mRNAs. Our analysis identified widespread association of mRNAs with cytoskeletal motor proteins, including association of Myo3 with mRNAs encoding key regulators of actin branching and endocytosis such as WASP and WIP. Using conventional fluorescence microscopy and expression of MS2-tagged mRNAs from endogenous loci, we observed a strong bias for actin patch nucleator mRNAs to localize to the cell cortex and the actin patch in a Myo3- and F-actin dependent manner. Use of a double-helix point spread function (DH-PSF) microscope allowed super-localization measurements of single mRNPs at a spatial precision of 25 nm in x and y and 50 nm in z in live cells with 50 ms exposure times, allowing quantitative profiling of mRNP dynamics. The actin patch mRNA exhibited distinct and characteristic diffusion coefficients when compared to a control mRNA. In addition, disruption of F-actin significantly expanded the 3D confinement radius of an actin patch nucleator mRNA, providing a quantitative assessment of the contribution of the actin cytoskeleton to mRNP dynamic localization. Our results provide evidence for specific association of mRNAs with cytoskeletal motor proteins in yeast, suggest that different mRNPs have distinct and characteristic dynamics, and lend insight into the mechanism of actin patch nucleator mRNA localization to actin patches.

Measurements of H-->D-->(gamma-->,pi) and implications for the convergence of the Gerasimov-Drell-Hern integral.

We report new measurements of inclusive pi production from frozen-spin HD for polarized photon beams covering the Delta(1232) resonance. These provide data simultaneously on both H and D with nearly complete angular distributions of the spin-difference cross sections entering the Gerasimov-Drell-Hearn (GDH) sum rule. Recent results from Mainz and Bonn exceed the GDH prediction for the proton by 22 microb, suggesting as yet unmeasured high-energy components. Our pi0 data reveal a different angular dependence than assumed in Mainz analyses and integrate to a value that is 18 microb lower, suggesting a more rapid convergence. Our results for deuterium are somewhat lower than published data, considerably more precise, and generally lower than available calculations.

Measurement of turnout in dance research: a critical review.

Turnout measurement procedures, results, and reporting formats vary in dance medicine and science research, making comparisons difficult. It is agreed that turnout results from summative contributions of the hip, knee, lower-leg, and the foot-ankle complex. However, the most frequently reported measurement is hip external rotation, and even this is measured in incompatible ways. No normative data exist for component and summative measures or for different categories of dancers, making screening, clinical assessment, and research problematic. Thus, there is a need to standardize component measurements, develop an inclusive measurement procedure for total turnout, and establish normative data for each measurement and for different categories of dancers. This review evaluates the 24 published articles that have reported original data for turnout assessment in dancers. Results are summarized and displayed for each article. In conclusion, recommendations are made for: use of selected hip external range of motion and tibial version measurements as the most important components of turnout; a procedure for assessing total turnout; adoption of conventions for reporting data in compatible forms; and the development of normative data sets for different categories of dancers.

A simple solution for reducing artefacts due to conductive and dielectric effects in clinical magnetic resonance imaging at 3T.

The quality of imaging obtained at high magnetic field strengths can be degraded by various artefacts due to conductive and dielectric effects, which leads to loss of signal. Various methods have been described and used to improve the quality of the image affected by such artefacts. In this article, we describe the construction and use of a simple solution that can be used to diminish artefacts due to conductive and dielectric effects in clinical imaging at 3T field strength and thereby improve the diagnostic quality of the images obtained.

Neoadjuvant chemotherapy in breast cancer: early response prediction with quantitative MR imaging and spectroscopy.

A prospective study was undertaken in women undergoing neoadjuvant chemotherapy for locally advanced breast cancer in order to determine the ability of quantitative magnetic resonance imaging (MRI) and proton spectroscopy (MRS) to predict ultimate tumour response (percentage decrease in volume) or to detect early response. Magnetic resonance imaging and MRS were carried out before treatment and after the second of six treatment cycles. Pharmacokinetic parameters were derived from T1-weighted dynamic contrast-enhanced MRI, water apparent diffusion coefficient (ADC) was measured, and tissue water:fat peak area ratios and water T2 were measured using unsuppressed one-dimensional proton spectroscopic imaging (30 and 135 ms echo times). Pharmacokinetic parameters and ADC did not detect early response; however, early changes in water:fat ratios and water T2 (after cycle two) demonstrated substantial prognostic efficacy. Larger decreases in water T2 accurately predicted final volume response in 69% of cases (11/16) while maintaining 100% specificity and positive predictive value. Small/absent decreases in water:fat ratios accurately predicted final volume non-response in 50% of cases (3/6) while maintaining 100% sensitivity and negative predictive value. This level of accuracy might permit clinical application where early, accurate prediction of non-response would permit an early change to second-line treatment, thus sparing patients unnecessary toxicity, psychological morbidity and delay of initiation of effective treatment.

Differentiation of benign from malignant breast disease associated with screening detected microcalcifications using dynamic contrast enhanced magnetic resonance imaging.

Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) is an effective diagnostic modality for symptomatic breast disease. However, its role in evaluating clinically occult disease associated with mammographically detected microcalcification remains unclear. Women recalled following screening mammography with microcalcification had DCE-MRI examination of the breast. The data were evaluated subjectively and objectively using both empirical and 2-compartment pharmacokinetic modelling techniques to evaluate signal intensity parameters. Eighty-eight patients aged 50-75 years (median 58) were recruited. Comparing malignant and benign lesions, the mean values in arbitrary units for the enhancement index at 1 min in the most enhancing 9-pixel square +/-1 standard deviation were 0.61+/-0.40 vs. 0.22+/-0.26 p=<0.001 with sensitivity, specificity, PPV, NPV and accuracy of 80.0%, 82.4%, 57.1%, 93.3% and 81.8%, respectively. The corresponding values attained by the radiologist were 75.0%, 89.7%, 68.2%, 92.4% and 86.4%. DCE-MRI is able to differentiate malignant from benign clinically occult lesions associated with microcalcification and may therefore offer an alternative to open surgical biopsy for women with equivocal findings following initial triple assessment for microcalcification in the breast.

Differentiation of benign and malignant sub-1 cm breast lesions using dynamic contrast enhanced MRI.

The purpose of this work is to assess the additional benefit of MRI-based morphology and quantification of contrast enhancement in the differential diagnosis of sub-1cm breast lesions. Forty-three women with suspected breast cancer were examined using X-ray mammography, ultrasound mammography, and MRI. Dynamic contrast imaging was performed and relative enhancement at various time-points was calculated. The dynamic data was also processed using a two-compartment pharmacokinetic model. Radiological interpretation of high-resolution post-contrast images revealed a similar accuracy (69%) compared to X-ray mammography (69%) and ultrasound mammography (67%). The best individual parameter calculated from the dynamic images was found to be the exchange rate constant which revealed a diagnostic accuracy of 0.74 +/- 0.08. When information from the post-contrast images and dynamic data was combined in a logistic regression model a diagnostic accuracy of 0.92 +/- 0.03 was achieved. In conclusion, MR imaging of small breast lesions is feasible and the incorporation of quantitative MR derived parameters is beneficial.

Anal gland carcinoma.

BACKGROUND: Anal gland carcinoma is a rare entity. The authors conducted a joint study of cases coded as definite or possible anal gland carcinoma from the archives of the Armed Forces Institute of Pathology and the Canadian Reference Center for Cancer Pathology. METHODS: Seven cases of potential anal gland carcinoma were identified from the Canadian files and 12 from the Armed Forces Institute of Pathology archives. Of these 19 cases, 14 had adequate material to allow clinical, histologic, and immunohistochemical analysis. RESULTS: Seven of these 14 cases met a modified World Health Organization (WHO) definition of anal gland carcinoma. The mean age of these patients was 66 years (range, 60-72 years), with a male-to-female ratio of 6:1. The tumors were composed of haphazardly dispersed, small glands with scant mucin production that invaded the wall of the anorectal area with no obvious intraluminal component observed clinically or microscopically. Immunohistochemical studies were performed on all seven of these cases, revealing cytokeratin (CK) 7+/CK 20- expression in six cases, and CK 7+/CK 20+ expression in one case. The remaining seven cases showed no intraluminal component but did not meet a modified WHO definition of anal gland carcinoma. This group included three mucinous adenocarcinomas (two clinically arising in anal fistulas), all of which were CK 7+/CK 20+, and a rectal-type adenocarcinoma that was CK 7-/CK 20+. There was also a tumor interpreted as probable rectal-type adenocarcinoma that was CK 7+/CK 20+, and a tumor interpreted as probable squamous cell carcinoma that was CK 7-/CK 20-. The seventh tumor in this group, which could not be classified, was CK 7+/CK 20-. CONCLUSIONS: A useful and discriminating definition of anal gland carcinoma is an anal canal tumor composed of haphazardly dispersed, small glands with scant mucin production invading the wall of the anorectal area without an intraluminal component. The glands are positive for CK 7.

An open-label acceptability study of Norditropin SimpleXx--a new liquid growth hormone formulation.

A new liquid formulation of hGH (Norditropin SimpleXx) has been developed to avoid the need for reconstitution before administration. In addition, the liquid GH formulation has been combined with an advanced pen delivery system, either with or without a needle auto-insertion mechanism. This study was designed to assess the acceptability of the new system compared with the patient's previous system. A total of 103 children with GH deficiency received a daily injection of Norditropin liquid GH for 12 weeks with a choice of a pen/auto-insertion system. Acceptability was determined by nurse-supervised questionnaires administered to the patients and parents. Following treatment, 94% of patients preferred the Norditropin liquid GH system. This preference was irrespective of the previous system in use, patient age or length of GH therapy. More patients found it the less painful system (50% vs 13%), 92% of patients found it more convenient, and the formulation was well tolerated. In conclusion, Norditropin liquid GH was very well accepted and preferred by the majority of patients. It avoided reconstitution which had been a major cause of dissatisfaction with the patients' previous systems, and resulted in greater convenience and reduced levels of pain associated with injection.

Systematic review of proton magnetic resonance spectroscopy of the striatum in parkinsonian syndromes.

It has been suggested that proton magnetic resonance spectroscopy (MRS) of the striatum can differentiate between parkinsonian syndromes. The present study aims to examine this claim by performing a systematic review of the existing literature. A MEDLINE search was performed between 1966 and October 1999, along with searches of conference abstracts and reference lists of papers identified. Eleven groups have used MRS to examine metabolite ratios in the striatum in Parkinsonian syndromes. A number of these have shown reduced N-acetylaspartate/choline (NAA/Cho) and/or N-acetylaspartate/creatine (NAA/Cr) ratios in either idiopathic Parkinson's disease (IPD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP) or corticobasal degeneration. However, the heterogeneity in the results precludes the use of any of these findings in differential diagnosis at the present time. The only group to use absolute metabolite concentrations rather than ratios showed that the decreased NAA/Cho ratio in IPD was because of an increase in choline which is of uncertain biological significance. Further large multicentre trials are required using absolute quantitation of tissue metabolite concentrations and a standardized technique. The patients entering such studies must be rigorously assessed to establish the diagnosis of the type of parkinsonism as accurately as possible. Any discriminatory abnormality must be tested in a large prospective study of newly presenting parkinsonian patients with long-term clinical follow up and ultimate pathological confirmation of the diagnosis as far as possible.

Do adenoids regrow after excision?

OBJECTIVE: The goal was to determine the incidence of symptomatic adenoidal regrowth after adenoidectomy. STUDY DESIGN: A cross-sectional follow-up study was done in a randomly selected group of 175 children who had undergone adenoidectomy 2 to 5 years earlier. Nasopharyngoscopy was performed in those children who still had symptoms of nasal obstruction. SETTING: All surgery was performed at an academic hospital-based practice in the northeastern United States by a single surgeon using a consistent operative technique. RESULTS: Forty-six (26%) patients had nasal airway obstruction symptoms at follow-up. Of the 35 who agreed to undergo nasopharyngoscopy, not a single one had adenoids occupying more than 40% of the nasopharynx, and most (71%) were found to have either no or only trace amounts of adenoidal tissue (usually in the pharyngeal recess). CONCLUSION: Adenoids rarely, if ever, regrow enough to cause symptoms of nasal obstruction after adenoidectomy that includes visualization and electrocautery of the adenoid bed.

Fcgamma receptor-mediated phagocytosis in macrophages lacking the Src family tyrosine kinases Hck, Fgr, and Lyn.

Macrophage Fcgamma receptors (FcgammaRs) mediate the uptake and destruction of antibody-coated viruses, bacteria, and parasites. We examined FcgammaR signaling and phagocytic function in bone marrow-derived macrophages from mutant mice lacking the major Src family kinases expressed in these cells, Hck, Fgr, and Lyn. Many FcgammaR-induced functional responses and signaling events were diminished or delayed in these macrophages, including immunoglobulin (Ig)G-coated erythrocyte phagocytosis, respiratory burst, actin cup formation, and activation of Syk, phosphatidylinositol 3-kinase, and extracellular signal-regulated kinases 1 and 2. Significant reduction of IgG-dependent phagocytosis was not seen in hck(-)(/)-fgr(-)(/)- or lyn(-)(/)- cells, although the single mutant lyn(-)(/)- macrophages did manifest signaling defects. Thus, Src family kinases clearly have roles in two events leading to FcgammaR-mediated phagocytosis, one involving initiation of actin polymerization and the second involving activation of Syk and subsequent internalization. Since FcgammaR-mediated phagocytosis did occur at modest levels in a delayed fashion in triple mutant macrophages, these Src family kinases are not absolutely required for uptake of IgG-opsonized particles.

Basal ganglia metabolite concentrations in idiopathic Parkinson's disease and multiple system atrophy measured by proton magnetic resonance spectroscopy.

Six patients with idiopathic Parkinson's disease (IPD), six with clinically probable multiple system atrophy and six control subjects underwent quantitative proton magnetic resonance spectroscopy (MRS). The concentrations of the three major metabolites, N-acetylaspartate (NAA), creatine and choline, were quantified in the lentiform nucleus using tissue water content as an internal concentration reference. Glutamate was assessed as the (glutamate + glutamine)/creatine peak area ratio (Glx/Cre). In the control subjects the mean (+/- SD) concentrations of the three metabolites were 15.2 +/- 2.9 micromol/g wet weight for NAA, 12.0 +/- 1.4 for creatine and 2.4 +/- 0.3 for choline. The Glx/Cre ratio was 1.28 +/- 0.32. The only significant difference in any metabolite concentration was in the lentiform nucleus of patients with IPD compared with controls, with an increase in choline which lead to a significant reduction in the NAA/choline ratio. The relevance of this finding is uncertain. The results of the present pilot study, combined with the conflicting findings from previous work, suggest that further, much larger, studies are required to evaluate the diagnostic capability of proton MRS.

Combined proton MR spectroscopy and dynamic contrast enhanced MR imaging of human intracranial tumours in vivo.

A study was undertaken to determine if the vascular characteristics measured by dynamic contrast-enhanced magnetic resonance imaging (primarily permeability surface area product and extracellular-extravascular tissue volume fraction) would be beneficial in explaining the inter-lesion metabolic heterogeneity displayed by human intracranial tumours. Magnetic resonance spectroscopy was carried out using a single-voxel STEAM sequence and dynamic imaging was carried out using a combination of pre-contrast proton density-weighted FSPGR images (to remove the influence of native tissue T1), bolus injection of Gd-DTPA and subsequent T1-weighted FSPGR dynamic imaging. A two-compartment pharmacokinetic model was employed to determine vascular characteristics. Results obtained from 12 meningiomas suggest a possible correlation between the level of lipids/macromolecules and permeability surface area product, although the confounding issue of extra-voxel contamination arising from lipids in the scalp and skull marrow cannot be ruled out in the more superficial lesions. Results obtained from 11 gliomas (four low and seven high grade) demonstrate that permeability surface area product is not specific for the range of vascular characteristics and metabolite profiles observed in gliomas and is therefore unable to explain metabolic heterogeneity in these lesions.