A study of Light's criteria and possible modifications for distinguishing exudative from transudative pleural effusions

STUDY OBJECTIVE: To determine the usefulness of modifying Light's criteria for the separation of pleural transudates from exudates. DESIGN: Retrospective review of patients who underwent a diagnostic thoracentesis during a 2-year period. SETTING: Community teaching hospital in Lleida, Spain. PATIENTS AND METHODS: Clinical records and pleural fluid characteristics of 230 consecutive patients with pleural effusion underwent a detailed review. Thirty-five of these patients were excluded from the analysis. As suggested recently by Romero et al, different cutoff levels for the criteria of Light et al were applied and their accuracies were calculated. RESULTS: Thirty-nine (20%) pleural effusions were transudates and 156 (80%) were exudates. The accuracy of the criteria of Light et al for identifying exudates was 94.7% (confidence interval, 91.6 to 97.9) in comparison to our own modified criteria (93.1%; confidence interval, 89.5 to 96.7) and the criteria suggested by Romero et al (92.6%; confidence interval, 88.9 to 96.3). These differences were not statistically significant. CONCLUSION: Changing the classic Light's criteria with different cutoff points offers no advantages for discriminating between transudative and exudative pleural effusions.     

Rectal hemorrhage as a first sign of renal cell adenocarcinoma

We present a 3-year-old patient with stenotic kinking of the left internal carotid artery (ICA) who developed an ischaemic infarction of the left brain hemisphere followed by severe neurological sequelae after a prolonged generalized seizure. At time of the seizure the boy was in biological remission of a nephrotic syndrome and received prednisolone and cyclosporin A (CsA) treatment. The haemodynamic consequences of inborn kinking of the ICA is discussed controversely in the literature. The presented case shows that stenotic kinking of the ICA may significantly impair the blood flow towards the homolateral hemisphere and therefore may result in an ischaemic infarction. The influence of CsA on seizure activity is discussed. CONCLUSION: This case provides clinical and radiological evidence supporting an association between stenotic kinking of the carotid artery and homolateral hemispheric brain infarction.     

Transient heat conduction problems using B.I.E.M.

A method, using boundary elements, is presented as a solution to plane transient heat conduction. The proposed method considers the governing equation to be a Helmholtz's equation and solves the problem of time variation using step by step integration. A numerical procedure is developed and its effectiveness verified. Several examples are provided and their results compared with the theoretical ones.     

Polycyclic aromatic hydrocarbon content in commercial Spanish fatty foods

The levels of polycyclic aromatic hydrocarbons (PAHs) were determined by reversed-phase high-performance liquid chromatography with fluorescence detection in different fatty foods from a Spanish market. The average concentration of the sum of total PAHs in edible vegetable oils was below 25 ng/g, whereas the sum of heavy PAHs did not surpass 5 ng/g. Olive pomace oils obtained before the summer of 2001 were an exception because they were highly contaminated. The effects of different technological processes, such as bleaching, deodorization, and hydrogenation, on PAH concentration in edible oils have been studied. The PAH profiles, as well as the influence of cooking procedures, of other fatty foods (margarine, mayonnaise, and oils from canned fishes) have been examined.     

Determination of linear alkylbenzenesulfonates and their degradation products in soils by liquid chromatography-electrospray-ion trap multiple-stage mass spectrometry

Linear alkylbenzenesulfonates (LAS) (C(10)-C(13)) and their degradation products, sulfophenyl carboxylate compounds (SPCs) (C(2)-C(6), C(8), C(11)), have been extracted from soil samples with methanol, isolated, concentrated by solid-phase extraction, and determined by liquid chromatography/negative ion electrospray quadrupole ion-trap tandem mass spectrometry (MS(n)). The ion fragmentation processes and pathways were studied in detail by MS, MS(2), and MS(3). Upon collision-induced dissociation, the deprotonated molecules of LASs render the ethylene-substituted benzenesulfonate ion (m/z 183), the fragmentation of which gave the intense signal at m/z 119, corresponding to the ethylene-substituted phenoxide ion formed by the loss of sulfur dioxide. The fragmentation pattern of SPCs shows that, for the analytes of large carbon atom chains (>5C), the neutral loss of water is favored whereas for those of short carbon atoms chain, the loss of carbon dioxide is more frequent. Multiple reaction monitoring using isolation only for MS and using isolation and fragmentation for MS(2) and MS(3) were used to identify and quantify each compound. The three MS modes have been validated in terms of sensitivity, selectivity, and precision, showing that each MS stage used reduces sensitivity 10 times. Recoveries from soil were higher than 65% at LOQ level for all the analytes tested, except for C(2)-C(4) SPCs by any MS mode, with relative standard deviation lower than 19%. The utility of the method is demonstrated by successfully quantifying real samples treated with these products. Quantification limits for the methodology developed in this work ranged from 0.5 to 50 microg kg(-1) by MS, from 2 to 400 microg kg(-1) by MS(2), and from 20 to 4000 microg kg(-1) by MS(3). Concentration levels of LASs and SPCs-ranging from 0.1 to 15 mg kg(-1)-were found in soil samples amended with sludges, thus indicating their input and persistence in the soil compartment.     

Multivariate curve resolution applied to the analysis and resolution of two-dimensional [1H,15N] NMR reaction spectra

Multivariate curve resolution is proposed for the study of complex chemical reactions monitored by two-dimensional (2D) NMR spectroscopy. In particular, in this work, multivariate curve resolution is applied to the study of the reaction between (15)N-labeled cisplatin and the amino acid-nucleotide hybrid (Phac-Met-linker-p(5')dG). At several stages of the reaction, 2D [(1)H,(15)N] HSQC NMR spectra were acquired and stored in data matrices. In a first step, multivariate curve resolution was applied to analyze individually each one of these 2D spectra, allowing the resolution of the corresponding (1)H and (15)N one-dimensional correlation spectra. In a second step, the whole set of 2D spectra recorded along the reaction were simultaneously analyzed by multivariate curve resolution, allowing the resolution of the kinetic concentration profiles and of the pure 2D NMR spectra of each of the species detected along the reaction. Results finally obtained confirmed previously postulated reaction mechanisms involving the existence of two monofunctional adducts and of two bifunctional adducts, with the structure of one of them not completely resolved.     

Segmentation for robust tracking in the presence of severe occlusion

Tracking an object in a sequence of images can fail due to partial occlusion or clutter. Robustness to occlusion can be increased by tracking the object as a set of "parts" such that not all of these are occluded at the same time. However, successful implementation of this idea hinges upon finding a suitable set of parts. In this paper we propose a novel segmentation, specifically designed to improve robustness against occlusion in the context of tracking. The main result shows that tracking the parts resulting from this segmentation outperforms both tracking parts obtained through traditional segmentations, and tracking the entire target. Additional results include a statistical analysis of the correlation between features of a part and tracking error, and identifying a cost function that exhibits a high degree of correlation with the tracking error.     

Simple and stereoselective synthesis of sex pheromone of processionary mothThaumetopoea pityocampa (Denis and Schiff.)

A simple and stereoselective synthesis of (Z)-13-hexadecen-11-yn-1-yl acetate, the major component of the sex pheromone ofThaumetopoea pityocampa (Denis and Schiff.) is described. The procedure essentially involves formylation of a terminal acetylene to the corresponding aldehyde followed by a stereochemically controlled Wittig reaction, which has been studied under a variety of conditions.