Quantitative measurement of cartilage volume is possible using two-dimensional magnetic resonance imaging data sets.

PURPOSE: 3D Magnetic resonance imaging (MRI) scans are generally used for quantitative cartilage measurements in knee osteoarthritis. However, a great deal of MRI data is from 2D scans, often thought to be unsuitable for quantitative cartilage assessment. The goal of our study was to demonstrate that mLACS, a modified version of the Local Area Cartilage Segmentation (LACS) method, could be used to measure cartilage volume on 2D MRI images. METHODS: We studied 301 randomly selected subjects from the OA Biomarkers Consortium FNIH Study, a nested case-control study within the Osteoarthritis Initiative (OAI). The study comprised four subgroups based on radiographic and pain progression. We compared mLACS applied to 2D TSE scans to LACS on 3D DESS data. The Pearson's correlation coefficient was used to establish agreement between LACS and mLACS, standardized response means (SRMs) for responsiveness, and intra-class correlation coefficients (ICCs) to measure reader precision. Logistic regression in a case/control analysis was used to compare the clinical validity between the two methods. RESULTS: We found R2 = 0.76 for the correlation between LACS and mLACs. For LACS, the responsiveness was SRM = 0.49 compared to 0.39 for mLACS. The odds ratios (OR) for the primary case/control analyses were 1.62 for LACS and 1.78 for mLACS. The intra and inter reader reproducibility values for mLACS were ICC = 0.90 and 0.86, respectively. CONCLUSION: This study has demonstrated that a reproducible, responsive, and clinically valid quantitative measurement of cartilage volume can be made using 2D TSE scans with a modest loss of responsiveness compared to 3D scans.

Incident hand OA is strongly associated with reduced peripheral blood leukocyte telomere length.

OBJECTIVE: To evaluate the relationship of telomere length to the prevalence and incidence of hand osteoarthritis in a longitudinal cohort. DESIGN: We conducted a cross-sectional and longitudinal analysis of data from a subset of participants in the Osteoarthritis Initiative (OAI) recruited between February 2004 and May 2006. 274 individuals were eligible for the study based on availability of both baseline and 48-month hand radiographs and peripheral blood leucocyte telomere length data. Mean telomere length of peripheral blood leukocytes (PBL)s from the DNA samples was determined using a validated quantitative polymerase chain reaction (PCR)-based assay, and hand radiographs were analyzed and graded using the Kellgren-Lawrence scale. RESULTS: In joint -level analyses, prevalent Interphalangeal Joint Osteoarthritis (IPJOA) was significantly associated with PBL telomere length in the baseline sample in unadjusted analyses (RR = 2.84; 95% CI:0.87-9.29) or in models adjusted for age, sex, and body mass index (aRR = 1.10; 95% CI: 0.96-1.27). The association in crude and adjusted analyses appeared slightly stronger with incident IPJOA, especially in the subset with normal hands at baseline (aRR = 1.62; 95% CI: 1.02-2.57). PBL telomere length was also associated with prevalent HOA at baseline (significant in unadjusted analysis: RR = 1.22; 95% CI 1.06-1.42), but not after adjusting for covariates: aRR = 1.12; 95% CI: 0.96-1.30). The magnitude of association was stronger for incident HOA, especially incident symptomatic HOA (aRR = 1.53; 95% CI: 1.09-2.15). CONCLUSIONS: In summary, the results of this exploratory analysis are confirmatory of previous work showing a cross-sectional relationship between telomere length and HOA and add to the field by demonstrating an even stronger association with incident IPJOA, both radiographic and symptomatic.

Quantitative measurement of medial femoral knee cartilage volume - analysis of the OA Biomarkers Consortium FNIH Study cohort.

OBJECTIVE: Large studies of knee osteoarthritis (KOA) require well-characterized efficient methods to assess progression. We previously developed the local-area cartilage segmentation (LACS) software method, to measure cartilage volume on magnetic resonance imaging (MRI) scans. The present study further validates this method in a larger patient cohort and assesses predictive validity in a case-control study. METHOD: The OA Biomarkers Consortium FNIH Project, a case-control study of KOA progression nested within the Osteoarthritis Initiative (OAI), includes 600 subjects in four subgroups based on radiographic and pain progression. Our software tool measured change in medial femoral cartilage volume in a central weight-bearing region. Different sized regions of cartilage were assessed to explore their sensitivity to change. The readings were performed on MRI scans at the baseline and 24-month visits. We used standardized response means (SRMs) for responsiveness and logistic regression for predictive validity. RESULTS: Cartilage volume change was associated strongly with radiographic progression (odds ratios (OR) = 4.66; 95% confidence intervals (CI) = 2.85-7.62). OR were significant but of lesser magnitude for the combined radiographic and pain progression outcome (OR = 1.70; 95% CI = 1.40-2.07). For the full 600 subjects, theSRM was -0.51 for the largest segmented area. Smaller areas of cartilage segmentation were also able to predict the case-control status. The average reader time for the largest area was less than 20 min per scan. Smaller areas could be assessed with less reader time. CONCLUSION: We demonstrated that the LACS method is fast, responsive, and associated with radiographic and pain progression, and is appropriate for existing and future large studies of KOA.

Integration of accelerated MRI and post-processing software: a promising method for studies of knee osteoarthritis.

OBJECTIVE: Magnetic resonance imaging (MRI) is a widely used imaging modality for studies of knee osteoarthritis (OA). Compared to radiography, MRI offers exceptional soft tissue imaging and true three-dimensional (3D) visualization. However, MRI is expensive both due to the cost of acquisition and evaluation of the images. The goal of our study is to develop a new method to address the cost of MRI by combining innovative acquisition methods and automated post-processing software. METHODS: Ten healthy volunteers were scanned with three different MRI protocols: A standard 3D dual-echo steady state (DESS) pulse sequence, an accelerated DESS (DESSAcc), acquired at approximately half the time compared to DESS, and a multi-echo time DESS (DESSMTE), which is capable of producing measurements of T2 relaxation time. A software tool was used to measure cartilage volume. Accuracy was quantified by comparing DESS to DESSAcc and DESSMTE and precision was measured using repeat readings and acquisitions. T2 precision was determined using duplicate DESSMTE acquisitions. Intra-class correlation coefficients (ICCs), root-mean square standard deviation (RMSSD), and the coefficient of variation (CoV) were used to quantify accuracy and precision. RESULTS: The accuracies of DESSAcc and DESSMTE were CoV = 3.7% and CoV = 6.6% respectively, while precision was 3.8%, 3.0%, and 3.1% for DESS, DESSAcc and DESSMTE. T2 repositioning precision was 5.8%. CONCLUSION: The results demonstrate that accurate and precise quantification of cartilage volume is possible using a combination of substantially faster MRI acquisition and post-processing software. Precise measurements of cartilage T2 and volume can be made using the same acquisition.

Biological regeneration of ferric (Fe3+) solution during desulphurisation of gaseous streams: effect of nutrients and support material.

This paper evaluates the biological regeneration of ferric Fe3+ solution during desulphurisation of gaseous streams. Hydrogen sulphide (H2S) is absorbed into aqueous ferric sulphate solution and oxidised to elemental sulphur, while ferric ions Fe3+ are reduced to ferrous ions Fe2+. During the industrial regeneration of Fe3+, nutrients and trace minerals usually provided in a laboratory setup are not present and this depletion of nutrients may have a negative impact on the bacteria responsible for ferrous iron oxidation and may probably affect the oxidation rate. In this study, the effect of nutrients and trace minerals on ferrous iron oxidation have been investigated and the results showed that the presence of nutrients and trace minerals affects the efficiency of bacterial Fe2+oxidation. The scanning electron microscopy analysis of the geotextile support material was also conducted and the results showed that the iron precipitate deposits appear to play a direct role on the bacterial biofilm formation.

Fate of Salmonella Typhimurium in laboratory-scale drinking water biofilms.

Investigations were carried out to evaluate and quantify colonization of laboratory-scale drinking water biofilms by a chromosomally green fluorescent protein (gfp)-tagged strain of Salmonella Typhimurium. Gfp encodes the green fluorescent protein and thus allows in situ detection of undisturbed cells and is ideally suited for monitoring Salmonella in biofilms. The fate and persistence of non-typhoidal Salmonella in simulated drinking water biofilms was investigated. The ability of Salmonella to form biofilms in monoculture and the fate and persistence of Salmonella in a mixed aquatic biofilm was examined. In monoculture S. Typhimurium formed loosely structured biofilms. Salmonella colonized established multi-species drinking water biofilms within 24 hours, forming micro-colonies within the biofilm. S. Typhimurium was also released at high levels from the drinking water-associated biofilm into the water passing through the system. This indicated that Salmonella could enter into, survive and grow within, and be released from a drinking water biofilm. The ability of Salmonella to survive and persist in a drinking water biofilm, and be released at high levels into the flow for recolonization elsewhere, indicates the potential for a persistent health risk to consumers once a network becomes contaminated with this bacterium.

Combined activation of Ras and Akt in neural progenitors induces glioblastoma formation in mice.

Gliomas are the most common primary malignant brain tumours and are classified into four clinical grades, with the most aggressive tumours being grade 4 astrocytomas (also known as glioblastoma multiforme; GBM). Frequent genetic alterations in GBMs (refs 2-5) result in stimulation of common signal transduction pathways involving Ras, Akt and other proteins. It is not known which of these pathways, if any, are sufficient to induce GBM formation. Here we transfer, in a tissue-specific manner, genes encoding activated forms of Ras and Akt to astrocytes and neural progenitors in mice. We found that although neither activated Ras nor Akt alone is sufficient to induce GBM formation, the combination of activated Ras and Akt induces high-grade gliomas with the histological features of human GBMs. These tumours appear to arise after gene transfer to neural progenitors, but not after transfer to differentiated astrocytes. Increased activity of RAS is found in many human GBMs (ref. 11), and we show here that Akt activity is increased in most of these tumours, implying that combined activation of these two pathways accurately models the biology of this disease.

A high resolution deletion map of human chromosome Xp22.

We have developed a 32-interval deletion panel for human chromosome Xp22 spanning about 30 megabases of genomic DNA. DNA samples from 50 patients with chromosomal rearrangements involving Xp22 were tested with 60 markers using a polymerase chain reaction strategy. The ensuing deletion map allowed us to confirm and refine the order of previously isolated and newly developed markers. Our mapping panel will provide the framework for mapping new sequences, for orienting chromosome walks in the region and for projects aimed at isolating genes responsible for diseases mapping to Xp22.

New look at renal vasculature: 7 tesla nonenhanced T1-weighted FLASH imaging.

PURPOSE: To investigate the feasibility of 7 Tesla (T) nonenhanced high field MR imaging of the renal vasculature and to evaluate the diagnostic potential of various nonenhanced T1-weighted (T1w) sequences. MATERIALS AND METHODS: Twelve healthy volunteers were examined on a 7T whole-body MR system (Magnetom 7T, Siemens Healthcare Sector) using a custom-built eight-channel radiofrequency (RF) transmit/receive body coil. Subsequent to RF shimming, the following sequences were acquired (i) fat-saturated two-dimensional (2D) FLASH, (ii) fat-saturated 3D FLASH, and a (iii) fat-saturated 2D time-of-flight MR angiography (TOF MRA). SNR and CNR were measured in the aorta and both renal arteries. Qualitative analysis was performed with regard to vessel delineation (5-point scale: 5 = excellent to 1 = nondiagnostic) and presence of artifacts (5-point scale: 5 = no artifact present to 1 = strong impairment). RESULTS: The inherently high signal intensity of the renal arterial vasculature in T1w imaging enabled moderate to excellent vessel delineation in all sequences. Qualitative (mean, 4.7) and quantitative analysis (SNR(mean) : 53.9; CNR(mean) : 28.0) demonstrated the superiority of TOF MRA, whereas 2D FLASH imaging provided poorest vessel delineation and was most strongly impaired by artifacts (overall impairment 3.7). The 3D FLASH MRI demonstrated its potential for fast high quality imaging of the nonenhanced arterial vasculature, providing homogeneous hyperintense vessel signal. CONCLUSION: Nonenhanced T1w imaging in general and, TOF MRA in particular, appear to be promising techniques for good quality nonenhanced renal artery assessment at 7 Tesla.

Observations, Meteorites, and Models: A Preflight Assessment of the Composition and Formation of (16) Psyche.

Some years ago, the consensus was that asteroid (16) Psyche was almost entirely metal. New data on density, radar properties, and spectral signatures indicate that the asteroid is something perhaps even more enigmatic: a mixed metal and silicate world. Here we combine observations of Psyche with data from meteorites and models for planetesimal formation to produce the best current hypotheses for Psyche's properties and provenance. Psyche's bulk density appears to be between 3,400 and 4,100 kg m-3. Psyche is thus predicted to have between ~30 and ~60 vol% metal, with the remainder likely low-iron silicate rock and not more than ~20% porosity. Though their density is similar, mesosiderites are an unlikely analog to bulk Psyche because mesosiderites have far more iron-rich silicates than Psyche appears to have. CB chondrites match both Psyche's density and spectral properties, as can some pallasites, although typical pallasitic olivine contains too much iron to be consistent with the reflectance spectra. Final answers, as well as resolution of contradictions in the data set of Psyche physical properties, for example, the thermal inertia measurements, may not be resolved until the NASA Psyche mission arrives in orbit at the asteroid. Despite the range of compositions and formation processes for Psyche allowed by the current data, the science payload of the Psyche mission (magnetometers, multispectral imagers, neutron spectrometer, and a gamma-ray spectrometer) will produce data sets that distinguish among the models.

Biglycan is required for adaptive remodeling after myocardial infarction.

BACKGROUND: After myocardial infarction (MI), extensive remodeling of extracellular matrix contributes to scar formation and preservation of hemodynamic function. On the other hand, adverse and excessive extracellular matrix remodeling leads to fibrosis and impaired function. The present study investigates the role of the small leucine-rich proteoglycan biglycan during cardiac extracellular matrix remodeling and cardiac hemodynamics after MI. METHODS AND RESULTS: Experimental MI was induced in wild-type (WT) and bgn(-/0) mice by permanent ligation of the left anterior descending coronary artery. Biglycan expression was strongly increased at 3, 7, and 14 days after MI in WT mice. bgn(-/0) mice showed increased mortality rates after MI as a result of frequent left ventricular (LV) ruptures. Furthermore, tensile strength of the LV derived from bgn(-/0) mice 21 days after MI was reduced as measured ex vivo. Collagen matrix organization was severely impaired in bgn(-/0) mice, as shown by birefringence analysis of Sirius red staining and electron microscopy of collagen fibrils. At 21 days after MI, LV hemodynamic parameters were assessed by pressure-volume measurements in vivo to obtain LV end-diastolic pressure, end-diastolic volume, and end-systolic volume. bgn(-/0) mice were characterized by aggravated LV dilation evidenced by increased LV end-diastolic volume (bgn(-/0), 111+/-4.2 microL versus WT, 96+/-4.4 microL; P<0.05) and LV end-diastolic pressure (bgn(-/0), 24+/-2.7 versus WT, 18+/-1.8 mm Hg; P<0.05) and severely impaired LV function (EF, bgn(-/0), 12+/-2% versus WT, 21+/-4%; P<0.05) 21 days after MI. CONCLUSIONS: Biglycan is required for stable collagen matrix formation of infarct scars and for preservation of cardiac hemodynamic function.

Phosphorylation-dependent ubiquitination of cyclin E by the SCFFbw7 ubiquitin ligase.

Cyclin E binds and activates the cyclin-dependent kinase Cdk2 and catalyzes the transition from the G1 phase to the S phase of the cell cycle. The amount of cyclin E protein present in the cell is tightly controlled by ubiquitin-mediated proteolysis. Here we identify the ubiquitin ligase responsible for cyclin E ubiquitination as SCFFbw7 and demonstrate that it is functionally conserved in yeast, flies, and mammals. Fbw7 associates specifically with phosphorylated cyclin E, and SCFFbw7 catalyzes cyclin E ubiquitination in vitro. Depletion of Fbw7 leads to accumulation and stabilization of cyclin E in vivo in human and Drosophila melanogaster cells. Multiple F-box proteins contribute to cyclin E stability in yeast, suggesting an overlap in SCF E3 ligase specificity that allows combinatorial control of cyclin E degradation.

Laboratory analogue investigation of defusion and reappraisal strategies in the context of symbolically generalized avoidance.

The present study examined and compared the effects of 2 analogues of cognitive treatments-cognitive defusion and cognitive reappraisal-on symbolically generalized avoidance established using a basic behavioral laboratory paradigm. This back-translation design contributes to the development and validation of principle-based definitions of the applied constructs of defusion and reappraisal. Eighty-eight participants first underwent basic laboratory procedures designed to establish symbolically generalized avoidance in response to an arbitrary stimulus (a nonsense word). Participants were then randomized to defusion, reappraisal, or control conditions. The response variables were (a) equivalence responding-indicative of the trained relational network and analogous to the cognitive content responsible for symbolic generalization-and (b) avoidance-the behavioral impact of symbolic generalization. A between-groups analysis revealed that defusion and reappraisal significantly increased the odds of nonavoidance responding. Discrete-time survival mediation analyses provided preliminary support for the classification of defusion as a functional context intervention and reappraisal as a relational context intervention.

Psychometric properties and validation of the Sociocultural Attitudes Towards Appearance Questionnaire-4 (SATAQ-4) with a sample of Japanese adolescent girls.

The Sociocultural Attitudes Towards Appearance Questionnaire-4 (SATAQ-4) is a 22-item five-factor measure that assesses thin- and muscular-ideal internalization as well as appearance-related pressures from peers, family, and media. The scale has been validated in Western cultures, but has not yet been examined in Eastern samples. Two studies were conducted to examine the psychometric properties of the SATAQ-4 among 946 Japanese adolescent girls. In Study 1, exploratory factor analysis of the SATAQ-4 indicated that the five-factor structure was largely replicated with the exception of two cross-loading items. In Study 2, confirmatory factor analysis indicated good fit for the full 22-item and reduced 20-item versions of the measure. SATAQ-4 subscales exhibited good internal consistency and were correlated in the expected direction with experiences of appearance teasing, strategies to lose and/or gain weight, and drive for muscularity. Overall, results support the reliability and validity of the SATAQ-4 among Japanese adolescent girls.

Activation of stat3 and stat1 DNA binding and transcriptional activity in human brain tumour cell lines by gp130 cytokines.

In this study we examine the activation of the latent Stat family of transcription factors by the gp130 family of cytokines in cell lines derived from human brain tumours. Of the cytokines tested, oncostatin M resulted in the most dramatic induction of Stat1 and Stat3 in all cell lines analysed, as assessed by the formation of protein/DNA complexes. Interleukin-6, leukemia inhibitory factor, and ciliary neurotrophic factor also induced Stat complexes more selectively and to a lesser magnitude than oncostatin M. The kinetics of Stat1 and Stat3 activation was rapid and transient; the nuclear accumulation of DNA binding-proficient Stat protein was detected in the nucleus within minutes of cytokine induction. The transcriptional potential of the oncostatin M-activated Stat molecules was demonstrated in two glioma cell lines (U87-MG, SNB-19) by transient transfection experiments using a Stat-responsive reporter plasmid. Oncostatin M-dependent transcription from this reporter plasmid was reduced to uninduced levels by the inclusion of a dominant-negative Stat3 molecule, demonstrating that Stat molecules were responsible for the induction. These studies demonstrate that oncostatin M is the most potent activator of Stat molecules in a variety of brain tumour-derived cell lines, an observation that could have implications affecting the balance between proliferation/apoptosis of these cells.

Synthesis of proteoglycans is augmented in dystrophic mdx mouse skeletal muscle.

Mdx mice uniquely recover from degenerative dystrophic lesions through an intense myoproliferative response. The onset and progression of this process are controlled by a complex set of interactions between myoblasts and their environment. The presence of the extracellular matrix is essential for normal myogenesis. Proteoglycans are abundant components of the extracellular matrix. The synthesis of proteoglycans in mdx mice during skeletal muscle regeneration was evaluated. Incorporation of radioactive sulfate demonstrated a significant increase in the synthesis of several types of proteoglycans in mdx animals compared to age-matched controls. The size and charge of proteoglycans synthesized by the mdx mice remained unchanged. In particular, one of the up-regulated proteoglycans, the small chondroitin/dermatan sulfate proteoglycan decorin which is known to bind and to sequester transforming growth factor-beta, was investigated. Immunocytolocalization and in situ hybridization studies showed that decorin mainly accumulated in the endomysium, i.e. around individual skeletal muscle fibers from M. tibialis anterior and diaphragm.

Characterization of the Alu-rich 5'-flanking region of the human prothrombin-encoding gene: identification of a positive cis-acting element that regulates liver-specific expression.

The nt sequence of 6127 bp of sequence upstream of the human prothrombin-encoding gene (F2) has been determined. Since we previously characterized 417 bp of DNA immediately upstream from the transcription start point (tsp), 6544 bp of continuous flanking sequence are known. Eleven Alu repeat sequences present in this region comprise 45% of the sequence; other repetitive sequences were identified by searching GenBank. The tsp was found to be heterogeneous by exon mapping and primer extension analysis. To localize the cis-acting sequences responsible for the liver-specific expression of F2, hybrid cat genes were constructed with various lengths of F2 5'-flanking region cloned upstream from a promoterless cat gene. After transfection into HepG2 and HeLa cells, it was inferred that the region between nt -1101 and -798 was required for synthesis in HepG2 cells; no synthesis was observed using these constructs in HeLa cells. Two sequences for known liver-specific or regulatory cis-acting sequences were identified in this region.

Molecular cloning, functional expression and chromosomal localization of an amiloride-sensitive Na(+) channel from human small intestine.

Amiloride-sensitive Na(+) channels belonging to the recently discovered NaC/DEG family of genes have been found in several human tissues including epithelia and central and peripheral neurons. We describe here the molecular cloning of a cDNA encoding a novel human amiloride-sensitive Na(+) channel subunit that is principally expressed in the small intestine and has been called hINaC (human intestine Na(+) channel). This protein is similar to the recently identified rodent channel BLINaC and is relatively close to the acid sensing ion channels (ASICs) (79 and 29% amino acid identity, respectively). ASICs are activated by extracellular protons and probably participate in sensory neurons to nociception linked to tissue acidosis. hINaC is not activated by lowering the external pH but gain-of-function mutations can be introduced and reveal when expressed in Xenopus oocytes, an important Na(+) channel activity which is blocked by amiloride (IC(50)=0.5 microM). These results suggest the existence of a still unknown physiological activator for hINaC (e.g. an extracellular ligand). The presence of this new amiloride-sensitive Na(+) channel in human small intestine probably has interesting physiological as well as physiopathological implications that remain to be clarified. The large activation of this channel by point mutations may be associated with a degenerin-like behavior as previously observed for channels expressed in nematode mechanosensitive neurons. The hINaC gene has been mapped on the 4q31.3-q32 region of the human genome.

A workingperson's guide to deconvolution in light microscopy.

Thefluorescence microscope is routinely used to study cellular structure in many biomedical research laboratories and is increasingly used as a quantitative assay system for cellular dynamics. One of the major causes of image degradation in the fluorescence microscope is blurring. Deconvolution algorithms use a model of the microscope imaging process to either subtract or reassign out-of-focus blur. A variety of algorithms are now commercially available, each with its own characteristic advantages and disadvantages. In this article, we review the imaging process in the fluorescence microscope and then discuss how the various deconvolution methods work. Finally, we provide a summary of practical tips for using deconvolution and discuss imaging artifacts and how to minimize them.

Effect of beta 2-microglobulin on immunoglobulin production.

Chronic renal failure patients display high serum levels of beta 2-microglobulin (beta 2-M) and a pronounced defect in immunoglobulin production. In this light, the present study was conducted to investigate whether beta 2-M might influence the rate of antibody synthesis. Peripheral blood mononuclear cells (PBMC) from healthy subjects were cultured in the presence of beta 2-M (80 mg/l) for 7 days. Immunoglobulin concentrations were measured by ELISA-techniques in culture supernatants. Basal IgM levels were 390 +/- 10 ng/ml and increased to 940 +/- 216 ng/ml in the presence of beta 2-M. After PWM stimulation, IgM concentrations were 2654 +/- 614 ng/ml without and 3750 +/- 914 ng/ml with beta 2-M. IgG and IgA production by PBMCs was not influenced by beta 2-M in the culture medium. Likewise, the generation of beta 2-M by PBMCs was unchanged in the presence of exogenous beta 2-M in the medium. In terms of clinical relevance, serum beta 2-M levels of 28 uremic patients were correlated with capacity of their PBMCs for immunoglobulin production in vitro. However, there was no apparent correlation between beta 2-M serum levels and immunoglobulin synthesis in vitro. Taken together, beta 2-M seems to have a stimulatory effect on IgM synthesis in vitro. Whether this has some clinical meaning in patients with chronic renal failure remains to be investigated.