Integrated MRI assessment of regional function and perfusion in canine myocardial infarction

A single integrated examination using regional measurements of perfusion from contrast-enhanced MRI and three-dimensional (3D) strain from tissue-tagged MRI was developed to differentiate infarcted myocardium from adjacent tissue with functional abnormalities. Ten dogs were studied at baseline and 10 days after a 2-hour occlusion of the left anterior descending coronary artery (LAD). Strain was determined using a 3D finite element model. Two-dimensional measurements of hypoenhancing regions were highly correlated with myocardial viability (r = 0.96). Signal intensity versus time curves obtained from contrast-enhanced MRI were used for quantitative perfusion analysis. The remote and adjacent noninfarcted tissue of the dogs with LAD occlusion, as well as the infarcted tissue, exhibited abnormal deformation patterns as compared to normal dogs (positive predictive value (PPV) of strain determination of infarction = 66%). Integration of contrast-enhanced MRI results with 3D strain analysis enabled the delineation of the myocardial infarction (PPV = 100%) from functionally compromised myocardium. This integrated cardiac examination shows promise for noninvasive serial assessment of potentially jeopardized noninfarcted myocardium to study the process of infarct remodeling and expansion.     

Postsurgical bile leaks: endoscopic obliteration of the transpapillary pressure gradient is enough

OBJECTIVES: Bile leaks are a well documented complication of biliary surgery, occurring more frequently with laparoscopic procedures. Endoscopic therapy with a long biliary endoprosthesis traversing the site of the leak is effective. We have evaluated the hypothesis that equalizing biliary and duodenal pressures with a short transpapillary stent is an equally effective therapy for bile leaks. METHODS: Thirty one consecutive patients presenting over a 52-month period with postsurgical bile leaks were evaluated. Patients had been treated with long endoprostheses (stents or nasobiliary tubes), sphincterotomy, or short transpapillary stents. The success, complication rate, need for additional therapy, and hospitalization time of each therapeutic approach were determined. RESULTS: Endoscopic therapy was successful in all 25 patients in whom a bile leak could be documented. The clinical success, need for radiological drainage, length of hospitalization, and incidence of pancreatitis were similar for all methods of treatment. CONCLUSIONS: These results confirm that endoscopic therapy is highly successful in the treatment of postoperative bile leaks and suggest that the mechanism of healing is the equalization of bile duct and duodenal pressures, allowing flow of bile into the duodenum. The endoscopic placement of short transpapillary stents without sphincterotomy is a temporary, effective, and technically simple method of pressure equalization. This should be considered as the primary therapy for most postoperative bile leaks.     

Changes in sugar,organic acid,flavonol and carotenoid composition during ripening of berries of three seabuckthorn (<Emphasis Type="Italic">Hippophae rhamnoides</Emphasis> L.) cultivars

Soluble solid, sugar, organic acid, flavonol and carotenoid content were determined in seabuckthorn berries of the three German cultivars Askola, Hergo and Leikora, collected at different harvesting times, to provide a more thorough knowledge of quality changes occurring during ripening of the berries. The main organic acids were malic (1940–4660 mg/100 g), quinic (810–2820 mg/100 g), ascorbic (180–370 mg/100 g) and citric acid (90–160 mg/100 g). In all three cultivars a marked decline in total organic acid concentration was observed during ripening. The pattern of variation of sugars, glucose (0.26–2.10 g/100 g) and fructose (0.14–0.54 g/100 g), was somewhat different among the three cultivars. In all three cultivars ascorbic acid concentration decreased during ripening. The main flavonols were isorhamnetin (350–660 mg/kg), quercetin (30–100 mg/kg) and kaempferol (2–5 mg/kg). The trends of flavonol content during ripening were quite different among the three cultivars. The main carotenoids were zeaxanthin (30–150 mg/kg), -carotene (3–50 mg/kg) and -criptoxanthin (5–19 mg/kg). The genotype seemed to affect both the extent of carotenoid accumulation and the carotenoid profile but in all three cultivars ripening was accompanied by an increase in total carotenoid concentration. The various classes of antioxidants showed quite different patterns of variation during ripening, achieving their maximum level at different harvesting dates.     

Automatic identification of the pectoral muscle in mammograms

The pectoral muscle represents a predominant density region in most medio-lateral oblique (MLO) views of mammograms; its inclusion can affect the results of intensity-based image processing methods or bias procedures in the detection of breast cancer. Local analysis of the pectoral muscle may be used to identify the presence of abnormal axillary lymph nodes, which may be the only manifestation of occult breast carcinoma. We propose a new method for the identification of the pectoral muscle in MLO mammograms based upon a multiresolution technique using Gabor wavelets. This new method overcomes the limitation of the straight-line representation considered in our initial investigation using the Hough transform. The method starts by convolving a group of Gabor filters, specially designed for enhancing the pectoral muscle edge, with the region of interest containing the pectoral muscle. After computing the magnitude and phase images using a vector-summation procedure, the magnitude value of each pixel is propagated in the direction of the phase. The resulting image is then used to detect the relevant edges. Finally, a post-processing stage is used to find the true pectoral muscle edge. The method was applied to 84 MLO mammograms from the Mini-MIAS (Mammographic Image Analysis Society, London, U.K.) database. Evaluation of the pectoral muscle edge detected in the mammograms was performed based upon the percentage of false-positive (FP) and false-negative (FN) pixels determined by comparison between the numbers of pixels enclosed in the regions delimited by the edges identified by a radiologist and by the proposed method. The average FP and FN rates were, respectively, 0.58% and 5.77%. Furthermore, the results of the Gabor-filter-based method indicated low Hausdorff distances with respect to the hand-drawn pectoral muscle edges, with the mean and standard deviation being 3.84 +/- 1.73 mm over 84 images.     

Characterization of the mechanism of interaction in ibuprofen-Eudragit RL100 coevaporates

The present study is a preliminary exploration of the affinity between a carboxylic model drug, the nonsteroidal antiinflammatory agent ibuprofen (IBU) and Eudragit RL100 (RL) polymer. Due to the presence of a variable amount of quaternary ammonium groups in this matrix, physical and chemical interaction with the carboxylic drug can occur, which reinforces its scant mechanical dispersion in the polymer network and can ultimately affect its release profile in vitro and in vivo. To study these aspects, IBU was mixed at increasing weight ratios and in different chemical forms (free acid, sodium salt, and n-butyl ester), to investigate further the role of the carboxylic group in the interaction with the RL polymer. Therefore, IBU-RL solid dispersions (coevaporates) were obtained and fully characterized in the solid state through spectroscopic, calorimetric, and x-ray diffractometric analyses. The in vitro release pattern of the drug, in the different chemical states, was studied for the coevaporates, compared with drug-RL physical mixtures, along with drug adsorption profiles from aqueous solutions on the surface of the polymer granules.     

Linear focusing by a plane grating with curved grooves

We study the field diffracted by a plane grating with curved (parabolic) grooves. We will demonstrate that when a monochromatic plane wave is incident on a grating with parabolic grooves the diffracted field has a focal line whose position depends on the curvature radius of the parabolas and the incidence angle of the light onto the grating. The effect described has potential applications in grating-based devices for focusing light without requiring any additional optics.     

Effect of rheology and processing parameters on the EPD coatings of basic sol-gel particulate sol

Homogeneous thick silica coatings were prepared onto metals substrates by Electrophoretic Deposition (EPD) using particulate sol-gel sols. The synthesis of the sols was performed by mixing tetraethoxysilane and methyltriethoxysilane under basic catalysis. The synthesis, storage and processing conditions were optimised, correlating the rheological properties of the sols with EPD performance and reliability. Homogeneous and crack-free coatings are obtained when both, the synthesis and the deposition, are performed under tight conditions avoiding the contact with room humidity. The maximum crack-free thickness of the sintered coatings was 12 m, three times more than those obtained by dipping.