[Evaluation of practices in liberal medicine, the medical audit: a current topic].
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France↗
Biomedical subjects
M Amiel
Publications and source records attributed to M Amiel.
The long-term effects of hyaluronan during development of osteoarthritis following partial meniscectomy in a rabbit model.
OBJECTIVE: The long-term effect of hyaluronan (HA) on meniscus remodeling and articular cartilage preservation was assessed during the development of osteoarthritis following partial meniscectomy in a rabbit model. DESIGN: Approximately 60% of the region of each medial meniscus of 20 rabbit knees was excised bilaterally. The left knee joint was treated with five weekly intraarticular injections of 0.3 ml of HA, beginning 1 week after surgery. The right control knee was injected with PBS on the same schedule. Six months after surgery, animals were killed and the medial menisci and tibial articular cartilage were evaluated morphologically, histologically and biochemically. RESULTS: Meniscal regeneration was observed as newly synthesized translucent tissue, and image analysis revealed that the amount of this tissue was significantly greater in the HA-treated menisci than in the vehicle-treated menisci. Safranin-O staining and image analysis revealed the increased presence of glycosaminoglycans in the HA-treated menisci relative to vehicle-treated menisci while vascularity and biochemical parameters (hydration, total GAGs and reducible collagen crosslinks) were statistically similar in HA- and vehicle-treated menisci. Gross morphologic grading with India ink revealed a trend for less deterioration of tibial articular cartilage in the HA group (P=0.09) while Mankin's score of the HA-treated tibial articular cartilage was marginally lower than that of the vehicle group (P=0.06). Biochemical assessments showed a trend for higher total GAGs concentration in the HA-treated articular cartilage when compared to the vehicle treatment group (P=0.06). CONCLUSION: The present study has demonstrated that following partial meniscectomy, treatment with hyaluronan can enhance meniscal regeneration and may inhibit articular cartilage degeneration as long as six months post surgery.
Animals↗
[The new listing of medicals acts...is becoming!].
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European Union↗
Transforming growth factor beta one (TGF-beta 1) enhancement of the chondrocytic phenotype in aged perichondrial cells: an in vitro study.
BACKGROUND: Perichondrium is recognized as a tissue with chondrogenic potential yielding cells which can be used for osteochondral repair. Factors which influence the proliferative ability and chondrocytic phenotype of such cells include age and presence of specific growth factors, i.e. TGF-beta 1. The present in vitro study assessed proliferation and markers of chondrocytic phenotype in cells extracted from the rib perichondrium of four- to five-year-old aged rabbits, and assessed the effects of exogenously added TGF-beta 1 on those cells. METHODS: Assays included 3H-thymidine incorporation (cell proliferation), 35S-sulfate incorporation (proteoglycan synthesis) and quantitative RT-PCR for determination of type II collagen gene expression. RESULTS: The results demonstrated that addition of TGF-beta 1 to the culture media stimulated thymidine incorporation and proteoglycan synthesis up to four- and five-fold, respectively, in aged perichondrium-derived cells. Moreover, the exogenous addition of TGF-beta 1 to the culture media resulted in an upregulation of transcriptional expression of the type II collagen gene. CONCLUSIONS: In summary, the present study has demonstrated that exogenously added TGF-beta 1 can stimulate proliferation and chondrocytic phenotype in aged perichondrium-derived cells in vitro.
Age Factors↗
Prospective comparison of MR lung perfusion and lung scintigraphy.
This study attempted to assess the accuracy and potential of lung magnetic resonance (MR) perfusion imaging compared with perfusion scintigraphy in the evaluation of patients with suspected lung perfusion defects. The technique, which uses an inversion recovery turbo-FLASH sequence with ultra-short TE (1.4 msec), was tested in 24 patients suspected clinically of having acute pulmonary embolism (n = 19) and in patients with severe pulmonary emphysema (n = 5). Perfusion lung scintigraphy was performed within 48 hours prior to the MRI examination in both groups of patients. The dynamic study was acquired in the coronal plane and consisted of 10 images of 6 slices (a total of 60 images per series). Gadopentetate dimeglumine (0.1 mmol/kg) was manually injected as a compact bolus during the acquisition of the first image. Three senior radiologists reviewed all unprocessed two-dimensional coronal sections. They were blinded to clinical data and other imaging modalities. For the three observers, the average sensitivity and specificity of MR were 69% and 91%, respectively. The overall agreement between MR and scintigraphy appears to be good, with a good correlation between the two modalities (kappa = 0.63). However, the data showed variability depending on the location of the perfusion defect, with higher accuracy in the upper lobes. The agreement between MR perfusion and scintigraphy appears to be moderate in the left inferior lobe (kappa = 0.48). The data showed an overall good interobserver agreement (kappa = 0.66). MR perfusion of the lung is a promising technique in detecting lung perfusion defects.
Adult↗
[Comparison of iodixanol (Visipaque) and ioxaglate (Hexabrix) in coronary angiography and ventriculography: a double-blind randomized study].
OBJECTIVE: To evaluate and compare in a double-blinded and prospective study the incidence of adverse reactions between two contrast agents used for coronary angiography and ventriculography. The first agent was the non-ionic, dimeric, isotonic contrast medium iodixanol (Visipaque), the other was the ionic dimeric contrast medium ioxaglate (Hexabrix). METHODS: A total of 110 consecutive patients were randomized and received either iodixanol 320 mgl/ml or ioxaglate 320 mgl/ml. The efficacy, safety, tolerability and specific cardiovascular effects were evaluated. Adverse reactions were recorded during the procedure and during the first 24 hours after the examination. Hemodynamic and electrophysiological parameters were recorded before and after the ventricular injection and the first injections into the left and right coronary artery, respectively. RESULTS: The incidence of clinical adverse reactions was significantly different between iodixanol and ioxaglate (3% vs 28%, p = 0.0004). 24 patients (16 iodixanol; 8 ioxaglate) experienced no discomfort (sensation of warmth, coldness or pain), and the intensity of discomfort experienced by the remainder was similar for the two groups. No patient reported pain. During the 3 minutes after injection of contrast medium, the LV end-diastolic pressure increased but, apart from one reading, the increases with iodixanol were always significantly different (p < 0.05), and less than those for ioxaglate. During the same time period, heart rate was increased to a greater extent by ioxaglate (p < 0.05). QT interval was significantly (p < 0.05) prolonged with both ioxaglate and iodixanol, but the changes were less marked after iodixanol. The angiographic studies were of diagnostic quality for all patients and optimal diagnostic information was achieved in 92% of both groups. CONCLUSION: This randomized study shows that iodixanol and ioxaglate are of comparable diagnostic efficacy in coronary angiography and ventriculography, but that iodixanol is better tolerated by patients and results in less marked hemodynamic and eletrophysiological changes than does ioxaglate.
Adolescent↗
[Characterization of arterial stenosis using 3D imaging. Comparison of 3 imaging techniques (MRI, spiral CT and 3D DSA) and 4 display methods (MIP, SR, MPVR, VA) by using physical phantoms)].
INTRODUCTION: Accurate assessment of arterial stenosis is a major public health issue for the diagnosis and treatment of cardiovascular diseases. The number of imaging techniques and types of software for display of imaging data is increasing. Few studies that compare these different techniques are available in the literature. MATERIALS AND METHODS: Using phantoms to reproduce the main types of arterial stenosis, the authors compared three 3D acquisition techniques (MRA, CTA, and 3D DSA) and four types of display methods (MIP, SR, MPVR, and VA). The degree, the shape, and the location of different types of stenoses were analyzed by three experienced observers during two successive readings. Intra- and inter-observer reproducibility were assessed. The results of the various acquisition techniques and display methods also were compared to the digital reference data (CFAO) of the physical phantoms. RESULTS: The degree of intra- and inter-observer reproducibility for the assessment of shape and location of the stenoses was good. Visual assessment of the degree of stenosis showed significant differences between two observers as well as in two readings by one observer. The 3D DSA was the most accurate technique for assessing the degree of stenosis. CTA provided better results than MRA. MPVR provided an accurate assessment of the degree of the stenosis. 3D DSA and CTA assessed stenosis form and localization adequately, with no significant difference; both methods appeared to be more accurate than MRA. SR provided the best information on the eccentric nature of the stenosis. The shape was very well assessed by VA and MPVR. CONCLUSIONS: Even though 3D DSA is the most accurate acquisition technique for visualization, the combined use of SR and MPVR appears to be the best compromise to describe the morphology and degree of stenosis. Further improvements in automatic 3D image processing could offer a better understanding and increased possibilities for assessing arterial stenosis.
Angiography, Digital Subtraction↗
[Summary of the SFR seminar "Teleradiography"].
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Computer Communication Networks↗
Architectural remodeling in deep frozen meniscal allografts after total meniscectomy.
This study assesses the biological characteristics of cell repopulation and matrix remodeling in deep frozen meniscal allografts after total meniscectomy and allograft transplantation. Thirty-two mature New Zealand White rabbits were operated on, and the allografts were assessed at 12 and 26 weeks postsurgery. Before transplantation, fresh medial menisci were placed into liquid nitrogen to kill all intrinsic cells. Frozen meniscal allografts showed collagen remodeling coincident with revascularization and cellular repopulation. Biochemical characterization showed active collagen remodeling of the allografts at 12 and 26 weeks. In situ hybridization showed that expression of types I and III procollagen mRNAs were increased at 12 weeks, especially near the region of the synovial capsule. At 26 weeks after transplantation, the pattern of collagen-type expression progressed toward normal; that is, type I procollagen mRNA expression was prominent, whereas only a small amount of type III procollagen mRNA was observed. These data indicate the adaptation of the repopulating cells from the host to the frozen allograft at 26 weeks after transplantation.
Animals↗
[Diagnostic imaging of acute pulmonary embolism: critical analysis of the 1997 literature].
With variable symptoms and a nonspecific radiographic appearance, acute pulmonary embolism (APE) is a frequent and often undiagnosed cause of mortality and morbidity; thus, availability of an accurate, noninvasive screening examination is highly desirable. Until recently, various noninvasive imaging procedures have been used to detect APE, including ventilation-perfusion scanning, MR imaging and phlebography (or sonography). The low specificity of scintigraphy explains why pulmonary angiography remains the usual "gold standard" modality for detection of APE. However, with this procedure morbidity and mortality not zero-Helical computed tomography (HCT) seems to be an accurate technique for diagnosis of pulmonary embolism except for distal thrombi. Nevertheless the exact position of HCT in the classic algorithms remains to be defined, particularly in terms or cost-benefit results.
Cost-Benefit Analysis↗
[Study of the pharmacodynamic activity of daflon 500 mg].
Daflon 500 mg, micronized purified flavonoid fraction, composed of 90% diosmin and 10% hesperidin, possesses venotonic and vasculoprotective pharmacological properties, it reinforces venous tone by prolonging the activity of parietal norepinephrine. The pharmacodynamic properties of Daflon 500 mg were demonstrated by mercury stress gauge venous occlusion plethysmography during a double-blind placebo-controlled trial in 10 women not presenting any venous disease. Venous tone was significantly reinforced by the 1st hour after a single dose of 2 tablets of Daflon 500 mg. This effect persisted for 4 to 24 hours according to the mode of administration. The rapid action of Daflon 500 mg is due to micronization of its active ingredient into particles less than 2 microns, thereby considerably increasing its absorption.
Adult↗
The melting pot of "interventional" radiology.
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Medicine↗
Depth separation in ten observers with a new stereoscopic X-ray acquisition system.
The aim of this work was to assess the depth separation of a new X-ray digital stereo angiographic system through visualization on a stereoscopic monitor. Before starting the clinical trial of this new stereo-digital angiographic system, it seemed to us mandatory to assess the inherent performance of the system to depict depth information, as well as the ability of the users to work with it. With this idea we designed a global test based on the observation of a physical test object by the potential users of the system, during a session long enough to simulate an angiographic study. The acquisition system consisted of a twin focal-spot X-ray tube and a standard DSA DG 300 (General Electric/CGR). The stereo display was controlled by a liquid crystal modulator placed in front of a black-and-white monitor. Special polarized glasses worn by the observers allowed right- and left-image separation. Depth separation was measured in ten observers by means of a stereoscopic test object. Six of the ten observers were able to locate accurately three-dimensional patterns separated by a 12- to 1.5-mm gap. No learning effect was noticed. This result suggested that stereo display through wireless polarized glasses coupled to up-to-date digital subtraction angiography technology may provide an accurate and ergonomic way to a dimensional enhancement of X-ray angiography.
Angiography, Digital Subtraction↗
[Analysis of the diagnostic value of endovascular ultrasound with roc curves. Practical implications].
Intravascular ultrasound enables detection of the components of atherosclerotic plaques. The diagnostic value was assessed by ROC (receiver operating characteristic) curves on images acquired in vitro and correlated with the histological findings in 61 arteries. Five questions were asked of each operator; the reply was represented by a continuous variable in order to express all nuances of judgement. The area under the ROC curve, Az, was the criterion of performance (0.5 : chance response : 1.0 : all replies were accurate). Detection of plaque was satisfactory (Az = 0.89). The three layer appearance of muscular arteries was well recognised (Az = 0.94). The fibrous composition of a plaque was only just satisfactory (Az = 0.88) with 38.7% interindividual variability. The lipid composition of the plaque was poorly recognised (Az = 0.76) with large interindividual variability (52.8%) : hypoechogenicity was too ambiguous a sign from the acoustic point of view. A hypoechogenic zone must not be synonymous with a lipid plaque but a cellular zone. Calcium can almost always be detected (Az = 0.98) with a very low interindividual variability (10.7%), fibrohyaline progression of some plaques can be confusing. The authors present a more objective description of endovascular ultrasonographic images. They conclude that the diagnostic performance of 30 MHz intravascular ultrasound is satisfactory but several limitations are apparent in the interpretation of images, especially hypoechogenic zone and hyper-reflective zones with high attenuation.
Arteries↗
[MRI of the pulmonary parenchyma. Clinical value and research prospects].
MR imaging of the lung is handicapped by three negative influences. First, the low proton spin density in lung tissue results in a low signal-to-noise ratio relative to the surrounding structures. Second, cardiac and respiratory motion induce artifacts that tend to obscure fine structural detail in the lung. Third, a considerable magnetic susceptibility gradient, arising from the large surface areas of air and tissue interfaces, produces a very low value for T2*. MR imaging can be used to stage the activity of interstitial lung disease and for the diagnosis of lipoid pneumonia and pulmonary infarction. In combination with MR angiography, perfusion MR imaging might eventually become a test for pulmonary embolisms.
Forecasting↗
[Magnetic resonance angiography].
Magnetic resonance angiography (MRA) is a non invasive method for studying the morphology and the hemodynamic of vessels. MRA is becoming well-established for aorta examination and has replaced aortography. MRA is very competitive in screening for renovascular hypertension, intracranial aneurysm, for evaluation of the carotid bifurcation and diagnosis of venous sinus thrombosis. In the future, clinical applications will include pulmonary and coronary arteries.
Humans↗
ROC assessment of compressed wrist radiographs.
The aim of this paper is to validate a compression scheme applied on a medical image database of digitized wrist radiographs. The compression scheme adapts itself to local statistical properties of the images. The diagnostic quality of the reconstructed images is evaluated using a ROC protocol involving five medical experts. The results of this evaluation enable us to validate the compression scheme on this database with a compression ratio of 40 (0.2 bits per pixel).
Humans↗