[Emergency ultrasound on the chest].
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Chest Pain↗
Biomedical subjects
G Mathis
Publications and source records attributed to G Mathis.
[Ultrasound in pulmonary embolism: killing three birds with one stone].
Pulmonary embolism remains a great diagnostic challenge. The value of different ultrasound methods is presented in this review. Regarding the accuracy of echocardiography, it shows a sensitivity of 41 - 50 % and a specifity of 90 % for unselected patients with suspicion of PE as a result. On the other hand, the sensitivity of echocardiography in cases of hemodynamic instable patients is very high. In a recent multicenter trial of thoracic ultrasound in diagnosis of pulmonary embolism on 352 patients the sensitivity amounts to 74 %, the specifity to 95 %, the positive predictive value to 95 %, negative predictive value to 75 % and accuracy to 84 %. Colour Doppler sonography with compression is a save modality ensuring the source of embolism in deep vein thrombosis. With suspicion of deep vein thrombosis the median sensitivity made up 95 % (38 - 100 %) and median specifity was 97 % (81 - 100 %). The combination of chest sonography, echocardiography and compression sonography of leg vein thrombosis enhances the sensitivity of sonography to 92 %, while this accuracy can not be reached with any other method.
Diagnosis, Differential↗
[Ultrasound diagnosis in blunt thoracic trauma].
AIM: Aim of the study was to determine the rate of injuries detectable by ultrasonography in patients suffering from blunt thoracic trauma. PATIENTS AND METHODS: Ultrasonography of the thorax was prospectively performed in patients with blunt chest trauma additionally to the routine radiological diagnostic procedures. A comparison between ultrasonography and chest x-ray findings referring to the rate of detection of fractures and pleural effusions was performed. RESULTS: 100 patients were enrolled in the study. 23 of them were examined within 24 hours after the trauma, the remaining 77 were examined with a delay of more than 24 hours. The findings detectable by ultrasonography were the following: fractured rib 65%, fracture of sternum 7%, fracture of clavicle 1%, rib fracture with callus 3%, haematoma of the chest wall 11%, pleural effusion 37%, pneumothorax 1%, atelectasis 8%, pneumonia 1%, lung contusion 18%, splenic rupture 3%. Rib fractures were detected in 36% of the patients and pleural effusions were detected in 11%, respectively, by chest x-ray. CONCLUSION: Rib fractures and pleural effusions are commonly diagnosed by ultrasonography in patients with blunt thoracic trauma. Concerning the diagnosis of rib fractures (65% versus 36%) and pleural effusions (37% versus 11%), ultrasonography is superior to chest-x-ray. A new and remarkable result is that subpleural infiltrates which are supposed to be lung contusions are also detectable by ultrasonography.
Clavicle↗
[Thoraxsonography--part 2--Subpleural lung lesions].
In many cases of pulmonary diseases extending up to the pleura, ultrasound helps to identify the etiology of the lesion. There are several sonomorphological criteria to differentiate peripheral pulmonary consolidations. The sonomorphology of pneumonic lung infiltration reveals typical changes: bronchoaerogram, fluidobronchogram, parapneumonic effusion, abscess formation. The extent of infiltration is sometimes underestimated due to artefacts. In sonography lung cancers are echopoor, rounded and polypoid, show sharp and serrated margins. The accuracy of ultrasound-guided transcutane biopsy in carcinomas is higher than 90%. The rate of pneumothorax is 2.6%, those requiring drainage are about 1%. Haemoptyses occur 1-2% of the punctures, most commonly in cases of chronic pneumonia. When a pulmonary embolism develops, thoracic sonography in 70-90% reveals subpleural sound-permeable lesions: embolism-related alveolar edemas and hemorrhages--early reperfusionable infarcts and triangular late infarcts. In compression atelectasis there usually is a homogeneous, hyperechoic transformation, shaped like a pointed cap or a wedge.
Biopsy↗
[Thoraxsonography--Part 1: Chest wall and pleura].
The detection of lymph nodes and a careful interpretation of dignity is one of the main indications for chest wall sonography. Palpable unclear masses of the chest wall can undergo US guided puctures very easily. Either rib and sternum fractures are detectable very sensitively. In addition to the more sensitive detection than in normal X-ray also accompanying soft parts processes, pleural effusions and haematomas can be visualised. Despite the physical laws of ultrasound, approximately 70% of the pleural surface can be accessed by sonography. The normal parietal pleural can be visualized and delineated from circumscribed as well as diffuse pathological thickening. The normal visceral pleura is hidden by the total reflection at the surface of the aerated lung. Sonographic evidence of a pleural effusion can be obtained from 5 ml onwards and is much more sensitive than a chest X-ray, especially in supine position; false positive findings are not encountered. A more accurate estimation of the quantity of effusion can be made. Exudates are echogenic in one third of cases. Pleural thickening, nodular changes in the pleura, septa, and the formation of the quality of effusion can be made. Exual exudates, whereas transudates are always anechoic. Pleural metastases are characteristically hypoechoic and nodular-polypoid. Pleural mesotheliomas can be delineated nearly equally well on sonograms and on computed tomography. Morphological and, in particular, functional diagnosis of the diaphragm by means of sonography is both reliable and convincing.
Diagnosis, Differential↗
Differential diagnosis of focal liver lesions in signal-enhanced ultrasound using BR 1, a second-generation ultrasound signal enhancer.
AIM: The aim was to evaluate the diagnostic value of contrast-enhanced ultrasound in the differential diagnosis of focal liver lesions, in a blinded experiment. In clinical routine the examiner can generally be influenced by the patient's history. METHOD: 62 patients with focal liver lesions, which could not be clearly differentiated and diagnosed by conventional ultrasound, were examined with contrast-enhanced (BR1, SonoVue, Bracco) ultrasound and included in a blinded prospective and randomized study. The examinations performed on a Sequoia 512 (Acuson) in a coherent contrast imaging method were recorded by an S-VHS recorder and afterwards analyzed by an examiner who did not know the patient's history. The basis of the diagnosis was the dynamic appearance and enhancement of the ultrasound contrast enhancer in different phases of liver perfusion. The conformation of the diagnoses was made by corresponding reference methods, as computer tomography, magnetic resonance imaging, biopsy and clinical follow-up. RESULTS: The following diagnoses were confirmed by reference methods: 18 patients with metastases, 4 hepatocellular carcinomas, 19 haemangiomas, 6 focal nodular hyperplasias, 13 patients with focal fatty infiltration and 2 patients with focal fatty sparing. 59 out of 62 patients with one or more liver lesions were correctly diagnosed by contrast-enhanced ultrasound. CONCLUSION: Second-generation ultrasound contrast enhancers improve the differential diagnosis of benign and malignant liver lesions considerably, especially in a blinded study.
Adult↗
[Choledochal cyst--what to do?].
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Adult↗
Time resolved amplification of cryptate emission: a versatile technology to trace biomolecular interactions.
Fluorescence resonance energy transfer (FRET) in association with a time-resolved fluorescence mode of detection was used to design a new homogeneous technology suitable to monitor biomolecular interactions. A lanthanide cryptate characterised by a long lived fluorescence emission was used as donor and a cross-linked allophycocyanine was used as acceptor. This new donor/acceptor pair displayed an exceptionally large Forster radius of 9 nm. This allowed to build up a set of labelling strategies to probe the interactions between biomolecules with an emphasis on fully indirect cassette formats particularly suitable for high throughput screening applications. Herein we describe the basics of the technology, review the latest applications to the study of molecular interactions involved in cells and new oligonucleotides based assays.
Antigens, CD↗
A homogeneous caspase-3 activity assay using HTRF technology.
Caspases are cysteine proteases presenting a conserved active site that cleaves protein substrates at a highly specific position. They are involved in different aspects of the active cell death pathway. Most of them act through proteolytic degradations of cellular components. This paper describes the assay development, assay validation, and screening for inhibitors of this enzyme, which could be potential drug candidates. The assay uses homogeneous time-resolved fluorescence based on energy transfer from europium cryptate as donor to cross-linked allophycocyanin as acceptor (XL665). A double-tagged substrate, biotinyl-epsilon-aminocaproyl-L-aspartyl-L-glutamyl-L-valyl-Laspartyl-L-alanyl-L-propyl-N(epsilon)-(2,4-dinitrophenyl)-L-lysine-amide (biotin-X-DEVDAPK(dnp)-NH(2)), is conjugated with streptavidin cryptate and anti-dnp-XL665 monoclonal antibody. The close proximity between donor and acceptor induces a specific time-resolved fluorescence signal. In the presence of enzyme activity, the substrate cleavage induces an unlinking of the two fluorescent probes and, subsequently, the disappearance of the specific signal as a result of loss of proximity. Experiments to optimize the reagent concentration, incubation times, precision, reproducibility, and robustness are discussed in comparison with a fluorometric method.
Biological Assay↗
Allophycocyanin 1 as a near-infrared fluorescent tracer: isolation, characterization, chemical modification, and use in a homogeneous fluorescence resonance energy transfer system.
Allophycocyanin 1 (APC1), isolated from Mastigocladus laminosus, retains the same (alpha-beta)(3) trimeric structure as allophycocyanin (APC), but incorporates a peptide linker in its core leading to a 28% increase in its fluorescence quantum yield compared to APC. Moreover, APC1 exhibits an unexpectedly good stability at very low concentrations, at extreme pHs, or diluted in a low ionic strength medium whereas, under the same conditions, APC dissociates into an (alpha-beta) monomer, indicating that the peptide linker acts as a stabilizer of its trimeric structure. APC1 crosslinking experiments performed using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide gave a high reaction yield (95%) and showed a similar crosslinking process as previously described for APC. Fluorescence quantum yields of crosslinked APC1 or APC decrease by 20% after labeling on antibody or streptavidin. However, quantum yields of the crosslinked APC1 conjugates remain 25% higher than those of crosslinked APC conjugates. Associated with a europium trisbipyridine cryptate as donor, crosslinked APC1 was compared with crosslinked APC as acceptor in homogeneous time resolved fluorescence technology based on a fluorescence resonance energy transfer process. Using crosslinked APC1, assay performances were increased by 20%, showing that APC1 could be considered as a very promising near infrared fluorescent probe to replace APC in its biological applications.
Chromatography, Gel↗
Homogeneous time resolved fluorescence resonance energy transfer using rare earth cryptates as a tool for probing molecular interactions in biology.
A homogeneous assay technology using time resolved fluorescence and fluorescence resonance energy transfer is described. A new class of fluorescent complexes, the cryptates, have been used as fluorescent donor with cross-linked allophycocyanin as acceptor. This new donor/acceptor shows an exceptionally high Förster distance R0 of 9 nm. This allows to build up a set of strategies to probe the interactions of biomolecules in biology, particularly for high throughput screening applications. In this article, we describe the basics of the technology and review applications developed for studying different key molecular interactions involved in cellular processes.
Cell Membrane↗
A homogeneous europium cryptate-based assay for the diagnosis of mutations by time-resolved fluorescence resonance energy transfer.
Oligonucleotide ligation assay (OLA) is considered to be a very useful methodology for the detection and characterization of mutations, particularly for clinical purposes. The fluorescence resonance energy transfer between a fluorescent donor and a suitable fluorophore as acceptor has been applied in the past to several scientific fields. This technique is well adapted to nucleic acid analysis such as DNA sequencing, DNA hybridization and polymerase chain reaction. We describe here a homogeneous format based on the use of a rare earth cryptate label as donor: tris-bipyridine-Eu(3+). The long-lived fluorescence of this label makes it possible to reach a high sensitivity by using a time-resolved detection mode. A non-radiative energy transfer technology, known as time-resolved amplification of cryptate emission (TRACE((R))) characterized by a temporal and spectral selectivity has been developed. The TRACE((R)) detection of characterized single nucleotide polymorphism using the OLA for allelic discrimination is proposed. We demonstrate the potentialities of this OLA-TRACE((R)) methodology through the analysis of K-ras oncogene point mutations.
DNA, Neoplasm↗
[Lung and pleural ultrasound].
Palpable nodules at the chest wall (e.g. lymph nodes) and rib fractures can be characteristically visualized by ultrasound. The simplest method and most sensitive technique to image and measure pleural fluid is ultrasound. Sonographic evidence of pleural nodules is a specific finding in patients with malignant effusions. Peripheral pulmonary consolidations are visible by ultrasound if they extend up to the pleura. One can image pleuritis, pneumonia, lung cancers, pulmonary infarction, and atelectasis in typical sonomorphology, but limited specificity. Ultrasound guided transthoracic puncture is minimally stressfulfor the patient, is accurate, has a low rate of complications and is also cost effective.
Diagnosis, Differential↗
[Sonographic findings in interstitial lung diseases].
UNLABELLED: Up to now, sonography of the thorax has not been taken into consideration in cases of interstitial lung disease because of its technical limitations. This study was aimed at examining pleural and subpleural alterations in cases of interstitial lung disease and comparing the sonographic method with the usual imaging procedures such as x-ray and computer tomography. PATIENTS AND METHODS: 24 patients, aged 25 to 70 who were diagnosed as suffering from an interstitial lung disease and underwent sonography of the thorax, were analysed with regard to the following criteria: 1 pleural effusions, 2 pleural fragmentations, 3 subpleural infiltrations > 2 mm, 4 pleural nodules. RESULTS: Six patients were diagnosed to have small pleural effusions which had not been visible on x-ray-scans. 14 patients showed pleural fragmentations, 10 patients had subpleural infiltrations, and in one patient pleural nodules could be detected. Out of the 24 patients suffering interstitial lung disease, sonographic alterations were diagnosed in 17 cases (= 71%). Among the 9 patients definitively suffering from sarcoidosis, five had had a completely inconspicuous ultrasonic result, four of them with sarcoidosis stage I. CONCLUSION: Sonography of the thorax has proved to be an excellent complementing examination method in cases of interstitial lung disease. The advantages lie in the possible detection of small pleural effusions and small subpleural infiltrations, where this method can also be used to monitor therapy.
Adult↗
Synthesis of 8-(omega-Hydroxyalkyl)-, 8-(omega-hydroxyalk-1-enyl)-, and 8-(omega-hydroxyalk-1-ynyl)adenines using the tert-butyldimethylsilyloxymethyl group, a new and versatile protecting group of adenine.
The synthesis of 12 analogues of adenine substituted at C-8 by an omega-hydroxyalkyl, omega-hydroxyalk-1-enyl, or omega-hydroxyalk-1-ynyl chain of various length has been carried out in five or six steps starting from adenine. The analogues were obtained using a new protecting group of adenine, the tert-butyldimethylsilyloxymethyl group. 9-tert-Butyldimethylsilyloxymethyl-adenine is more soluble than adenine in organic solvents. It was prepared regiospecificaly in two steps from adenine and was amenable to C-8 iodination under basic conditions and to subsequent introduction of the various carbon chains at C-8 by palladium-catalyzed cross-coupling reactions (Stille or Sonogashira). The protecting group was removed under acidic conditions, thus demonstrating its versatility.
Adenine↗
Europium cryptate-tethered ribonucleotide for the labeling of RNA and its detection by time-resolved amplification of cryptate emission.
TRACE (time-resolved amplification of cryptate emission), also called HTRF for pharmaceutical applications, is a homogeneous time-resolved fluorescence technique well adapted for the study of molecular interactions. It is based on fluorescence resonance energy transfer (FRET) between europium trisbipyridine cryptate (TBPEu(3+)) as energy donor and cross-linked allophycocyanin, symbolized by XL665, as acceptor, leading to a long-lived FRET signal. TBPEu(3+)-labeled uridine triphosphate (UTP), referred to as K-11-UTP in the text, was obtained by coupling TBPEu(3+) moiety to a C-5 functionalized UTP analog. K-11-UTP can be directly incorporated in RNA strands during enzymatic synthesis. This was demonstrated in an in vitro transcription reaction promoted by T(7) RNA polymerase. The reaction was performed in the presence of K-11-UTP and biotin-labeled cytidine triphosphate (biotin-16-CTP) in admixture with natural ribonucleotides. After the addition of streptavidin-XL665 conjugate (SA-XL665), which binds on biotinylated cytidine residues, a long-lived FRET signal was obtained. This proved that both europium cryptate and biotin were incorporated into the same RNA strand and are close enough to generate a FRET signal. The study of this FRET detection assay format showed that such doubly labeled RNA can be easily detected even when a very low percentage of K-11-UTP is used (less than 1% of total UTP concentration). Europium-cryptate-labeled RNA can also be monitored using a homogeneous hybridization assay format involving a biotinylated probe. After the addition of SA-XL665, the FRET signal generated demonstrates the formation of RNA:DNA hybrids. Europium-cryptate-labeled nucleotide thus gives access to a new type of RNA nonisotopic labeling and homogeneous detection assays.
Biotinylation↗
[Ultrasonographic examination of peripheral lung areas].
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Carcinoma, Bronchogenic↗
Europium cryptate labeled deoxyuridine-triphosphate analog: synthesis and enzymatic incorporation.
The synthesis of an europium tris-bipyridine cryptate labeled 2'-deoxyuridine-5 '-triphosphate analog (K-11-dUTP) is described. This labeled triphosphate was incorporated into DNA through enzymatic reactions with terminal transferase and DNA polymerases. The enzymatic reactions were monitored by TRACE (Time Resolved Amplification of Cryptate Emission), a homogeneous method using Fluorescence Resonance Energy Transfer (FRET) from an europium cryptate as donor to a modified allophycocyanine as acceptor.
DNA↗