[Feasibility study of dynamic contrast enhanced magnetic resonance imaging qualitative diagnosis of musculoskeletal tumors].

OBJECTIVE: To investigate the feasibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters in differentiating musculoskeletal tumors with different behaviours of pathological findings before therapy. METHODS: A total of 34 subjects of musculoskeletal tumors were involved in this retrospective analysis. DCE-MRI was performed using a fat-saturated 3D VIBE (volumetric interpolated breath-hold exam) imaging sequence with following parameters: FA, 10 degree; TR/TE, 5.6/2.4 ms; slice thickness, 4.0 mm with no intersection gap; field of view, 310 mm×213 mm; matrix, 256×178; voxel size, 1.2 mm×1.2 mm×4.0 mm; parallel imaging acceleration factor. The actuation time for the DCE-MRI sequence was 255 s with a temporal resolution of 5 s and 40 image volumes. Using pathological results as a gold standard, tumors were divided into benign, borderline and malignant tumors. Toft's model was used for calculation of K(trans) (volume transfer constant), Ve (extravascular extracellular space distribute volume per unit tissue volume) and Kep (microvascular permeability reflux constant). Those parameters were compared between the lesions and the control tissues using paired t tests. The one-way analysis of variance was used to assess the difference among benign, borderline and malignant tumors. P values <0.05 difference was statistically significant. RESULTS: Based on the WHO Classification of Tumours of Soft Tissue and Bone(2012) criteria, 34 patients were divided into three groups: 11 for benign tumors, 12 for borderline tumors, and 11 for malignancies. Compared with control tissues, K(trans) and Kep showed no difference, but Ve was increased in benign tumors, Kep showed no difference, but K(trans) and Ve were increased in borderline tumors,K(trans), Kep and Ve were increased in malignant tumors. K(trans) (P<0.001) and Kep (P<0.01) were significantly higher in malignant tumors than in benign and borderline tumors, but did not show any difference between benign tumors and borderline tumors. Ve was significantly higher in malignant tumors than in benign (P<0.05), but did not show any difference between malignant and borderline tumors, benign tumors and borderline tumors (P>0.05). CONCLUSION: DCE-MRI technique is useful to evaluate the pathological behaviour of musculoskeletal tumors. The quantitative analysis of DCE parameters in conjunction with conventional MR images can improve the accuracy of musculoskeletal tumor qualitative analysis.

Disease severity prediction for nursing home-acquired pneumonia in the emergency department.

BACKGROUND: Prediction rules exist for the assessment of community-acquired pneumonia but their use in nursing home-acquired pneumonia (NHAP) remains undefined. The objectives of this study were to compare the prognostic ability for severe NHAP of five prediction rules (PSI, CURB-65, M-ATS, R-ATS, España rule), and to evaluate their usefulness to identify patients with less severe disease in the emergency department for outpatient care. METHODS: A prospective observational study of consecutive NHAP patients was conducted at a university teaching hospital emergency department in Hong Kong between January 2004 and June 2005. The primary outcome was severe pneumonia (defined as combined 30-day mortality and/or intensive care unit (ICU) admission). RESULTS: 767 consecutive NHAP patients were included. Mean (SD) age was 83.4 (9.0) years; 350 (45.6%) were male and 644 (84.0%) had coexisting illness. 95 patients died within 30 days (12.4%), five patients were admitted to the ICU (0.7%) and 98 patients had severe pneumonia (12.8%). Sensitivity and specificity of each decision rule ranged from 37.8% to 95.9% and 15.1% to 87.6% respectively. The overall predictive performance of each rule was between 0.627 and 0.712. The negative likelihood ratios of PSI (0.27) and CURB-65 (0.23) were lower than M-ATS (0.71), R-ATS (0.45) and España (0.39). After excluding 204 patients with either poor functional status or those >90 years of age, sensitivities of M-ATS (96.0%) and R-ATS (100%) improved greatly with negative likelihood ratios of <0.1. CONCLUSION: PSI and CURB-65 are useful for identification of patients with less severe NHAP.

[Determination of ciprofloxacin in urine using terbium ion as fluorescent probe].

Factors effecting the fluorescence characteristics of the reaction CPFX-Tb were studied thoroughly. The effect of the experimental conditions on the fluorescence intensity was defined. In the pH 6.0 media, CPFX-Tb complex fluorescence system can emit intrinsic fluorescence of Tb. The excitation and emission wavelengths are 328 nm and 545 nm. The linear range is 1.0 x 10(-8)-1.0 x 10(-6) mol.L-1. The regression equation is F = 1.57 + 4.87 x 10(8) c, r = 0.9999 with the detection limit of 5.0 x 10(-9) mol.L-1. It has been satisfactory for the determination of trace ciprofloxacin in urine by using terbium ion as fluorescent probe.

Evaluation of cellulase recycling strategies for the hydrolysis of lignocellulosic substrates.

Recycling of cellulases should lower the overall cost of lignocellulosiic bioconversion processes. In this study, three recycling strategies were evaluated to determine their efficiencies over five successive rounds of hydrolysis. The effect of lignin on recycling was examined by comparing water-washed, steam-exploded birch (WB; 32% lignin) and WB which had been further extracted with alkali and peroxide (PB; 4% lignin). When the cellulases were recovered from the residual substrates after partial hydrolysis of both substrates, the recovered cellulase activity toward the mixture of fresh and residual substrates decreased after each recycling step. When the cellulases in the supernatants were also recycled, up to 20% more activity could be recovered. In both of these cases, the recovered activities did not correspond to the activities expected from the amount of cellulase protein recovered during recycling. The best recovery was obtained when the cellulases were recovered from both the residue and the supernatant after complete hydrolysis of the PB substrate. In this case, all of the originally added cellulase activity could be recovered for four consecutive hydrolysis rounds. However, when the same recycling strategy was carried out using the WB substrate, the recovered cellulase activity declined quickly with each recycling round. In all three of the recycling strategies, lower cellulase activities were recovered from the substrates with higher lignin contents. (c) 1995 John Wiley & Sons, Inc.

Differential modulation of fos and jun gene expression by 1,25-dihydroxyvitamin D3.

1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) modulates the mitogenic response to alpha-thrombin either positively or negatively in vascular smooth muscle (VSM) cells depending upon the time at which cells are exposed to 1,25-(OH)2D3. We now examine the impact of 1,25-(OH)2D3 on the induction by alpha-thrombin of c-jun and c-fos mRNA. When 1,25-(OH)2D3 and alpha-thrombin were added simultaneously to rat VSM cells, c-jun expression was enhanced by five-fold compared to cells exposed to thrombin alone. However, when cells were exposed to 1,25-(OH)2D3 for 48h prior to thrombin, c-jun expression after alpha-thrombin was reduced to less than 25% of the level in cells exposed to thrombin alone. c-fos expression after alpha-thrombin was unaffected by 1,25-(OH)2D3. Thus 1,25-(OH)2D3 dramatically alters the ratio of jun/fos mRNA produced during the mitogenic response and may thus modulate the response to mitogens.

Automatic selection of molecular images from dark field electron micrographs.

A method is described which can be used objectively to select putative molecular images from dark field electron micrographs of unstained molecules. The only characteristic of the molecule required for automatic selection is an estimate of molecular weight. Structures are selected from micrographs by a series of steps including: low pass filtering, edge detection and mass determination. The procedure is shown to be reliable for images with signal-to-noise ratios of at least 4.0. Moreover, the method is insensitive to both the shape and the number of molecules in the image. Five different molecules with molecular weights between MW 330,000 and MW 4000 are successfully selected from low dose STEM and high dose tilt beam dark field electron micrographs.