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Biomedical subjects

D Mathieu

Publications and source records attributed to D Mathieu.

At least 55 records · Page 3Linked to original sources
PubMed1999

Benign and malignant hepatocellular tumors: evaluation of tumoral enhancement after mangafodipir trisodium injection on MR imaging.

The aim of this work was to study the ability of mangafodipir trisodium (Mn-DPDP)-enhanced MR imaging in differentiating malignant from benign hepatocellular tumors. Eleven patients with pathologically proved hepatocellular carcinomas, six with focal nodular hyperplasias, and one with a single hepatocellular adenoma were examined by spin-echo and gradient-echo T1-weighted sequences before, 1 h after, and 24 h after intravenous injection of Mn-DPDP (5 micromol/kg). Quantitative analysis including enhancement and lesion-to-liver contrast-to-noise ratio, and qualitative analysis including the presence of a central area and a capsule were done on pre- and post-Mn-DPDP-enhanced images. Enhancement was observed in all the tumors with significant improvement (p < 0.05) in contrast-to-noise ratio 1 h after, and 24 h after intravenous injection of Mn-DPDP. There were no significant differences in the mean enhancement and the mean contrast-to-noise ratio (CNR) between benign and malignant tumors. No enhancement was seen within internal areas observed in 7 hepatocellular carcinomas, and in 5 focal nodular hyperplasias, and within capsules which were observed in 9 hepatocellular carcinomas. In our study, Mn-DPDP increased CNR of both benign and malignant tumors but did not enable differentiation between benign and malignant tumors of hepatocellular nature.

Adenoma, Liver Cell↗
PubMed1999

A new prognostic classification for predicting survival in patients with hepatocellular carcinoma. Groupe d'Etude et de Traitement du Carcinome Hépatocellulaire.

BACKGROUND/AIMS: In patients with hepatocellular carcinoma, prediction of survival is difficult. The aim of this prospective study was to provide a simple classification for predicting survival of patients with hepatocellular carcinoma, based on a multivariable Cox model. METHODS: Seven hundred and sixty-one patients who presented with hepatocellular carcinoma from 24 Western medical centers were enrolled over a 30-month period. Patients were randomly assigned to either a training sample (n=506, with 418 deaths) from which a classification system was established, or a test sample (n=255, with 200 deaths) for validating its prognostic significance. RESULTS: Five prognostic factors were selected at the 0.0001 level: Karnofsky index <80% (relative risk of death=2.2, 95% confidence interval: 1.7-2.7), serum bilirubin >50 micromol/l (relative risk=2.1, 95% confidence interval: 1.7-2.6), serum alkaline phosphatase at least twice the upper limit of normal range (relative risk=1.6, 95% confidence interval: 1.3-2.0), serum alpha-fetoprotein >35 microg/l (relative risk=1.7, 95% confidence interval: 1.4-2.1), and ultrasonographic portal obstruction (relative risk=1.3, 95% confidence interval: 1.1-1.7). Three risk groups with different 1-year survival rates (72%, 34%, 7%) were derived, and independently validated in the test sample (79%, 31%, 4%). CONCLUSION: This classification could be useful in the assessment of prognosis from homogeneous groups of patients with respect to their expected outcome.

Adult↗
PubMed1999

Acute swelling of the limbs: magnetic resonance pictorial review of fascial and muscle signal changes.

OBJECTIVE: This pictorial review analyzes the magnetic resonance (MR) fascial/muscular changes in 69 patients referred as emergencies with acute swelling of the limbs (ASL) from various causes. METHODS AND MATERIAL: A prospective MR imaging (MRI) study of 69 patients referred as emergencies for ASL was performed. Our population consisted of 45 patients with skin and soft-tissue infections (cellulitis and necrotizing fasciitis, and pyomyositis), six patients with soft-tissue inflammatory diseases (dermatomyositis, graft-versus-host disease), 11 patients with acute deep venous thrombosis, three patients with rhabdomyolysis, one patient with acute denervation and three other patients with rare diseases. Hematomas, tumorous or infectious bone involvement and soft-tissue tumors were excluded. All studies included spin echo T1-weighted images and spin echo T2-weighted images. Gadolinium-enhanced spin echo T1-weighted images were obtained when an abscess was suspected on T2-weighted images. Selective fat-saturated T1- and T2-weighted sequences were also used. MRI analysis was performed to obtain a compartmentalized anatomical approach according to the location of signal abnormalities in subcutaneous fat, superficial and deep fascia and muscle. RESULTS: In all patients with ASL, MRI demonstrated soft-tissue abnormalities involving subcutaneous fat, superficial fascia, deep fascia, or muscle. Although MR findings were non-specific, MRI appears sensitive for detecting subtle fascial and muscle signal changes. CONCLUSIONS: In skin and soft-tissue infections, MRI can be helpful for therapeutic management by determining the depth of soft-tissue involvement, particularly within fasciae and muscles, which is partly related to the severity of cellulitis with severe systemic manifestations. MRI can also aid the surgeon in diagnosing abscesses. In inflammatory diseases, MRI can determine the best site for biopsy and also monitor therapeutic response.

Adolescent↗
PubMed1999

New enzyme immunoassays for sensitive detection of circulating Candida albicans mannan and antimannan antibodies: useful combined test for diagnosis of systemic candidiasis.

Two standardized enzyme immunoassays for the serological diagnosis of candidiasis were developed. The first one detects antimannan antibodies, while the second one detects mannan with a sensitivity of 0.1 ng/ml. These tests were applied to 162 serum samples retrospectively selected from 43 patients with mycologically and clinically proven candidiasis caused by Candida albicans. Forty-three serum samples were positive for mannan, and 63 had significant antibody levels. Strikingly, only five serum samples were simultaneously positive by both tests. When the results were analyzed per patient, 36 (84%) presented at least one serum positive by one test. For 30 of them, positivity by one test was always associated with negative results by the other test for any of the tested sera. For six patients whose sera were positive for either an antigen or an antibody response, a balance between positivity by each test was evidenced by kinetic analysis of sera drawn during the time course of the infection. Controls consisted of 98 serum samples from healthy individuals, 93 serum samples from patients hospitalized in intensive care units, and 39 serum samples from patients with deep mycoses. The sensitivities and specificities were 40 and 98% and 53 and 94% for mannanemia or antibody detection, respectively. These values reached 80 and 93%, respectively, when the results of both tests were combined. These observations, which clearly demonstrate a disparity between circulation of a given mannan catabolite and antimannan antibody response, suggest that use of both enzyme immunoassays may be useful for the routine diagnosis of candidiasis.

Adult↗
PubMed1999

Gastric mucosal pH and blood flow during weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease.

To determine if gastric intramucosal pH changes during weaning from mechanical ventilation are related to gastric mucosal blood flow modifications, we studied 16 ventilator-supported patients with chronic obstructive pulmonary disease (COPD) who tolerated a 2-h trial of spontaneous breathing with pressure support ventilation and were successfully extubated and 11 patients with COPD who failed such a trial. Gastric mucosal perfusion was assessed using gastric intramucosal pH (pH(i)) by tonometry and laser-Doppler flowmetry. During the weaning attempt, the failure weaning group developed a rapid, shallow breathing pattern with acute respiratory acidosis. The pH(i) was lower and gastric intramucosal PCO(2) (PCO(2)im) was higher in the failure weaning group than in the successful weaning group (p < 0.05). No change in gastric intramucosal-arterial PCO(2) difference was observed and a linear correlation was found between arterial PCO(2) and PCO(2)im (r(2) = 0.70; p < 0.001). Cardiac index increased in the failure group (p < 0.05) and remained stable in the success group whereas gastric mucosal blood flow decreased in the failure group (H(120) (min): -22 +/- 11% from baseline; p < 0.05) and increased in the success group (H(120) (min): 85 +/- 27% from baseline; p < 0.05). We conclude that gastric intramucosal pH changes during a 2-h weaning trial are mainly due to arterial PCO(2) variations. Nevertheless, gastric mucosal blood flow changes do occur and differ according to the weaning success or failure.

Acid-Base Equilibrium↗
PubMed1999

[Identification and quantitative determination of chlorinated++ solvents after solid phase microextraction. Applications in hospital toxicology].

A simple method for the research and the identification of chlorinated solvents in biological fluids and tissues is described. The solvents are extracted using headspace solidphase microextraction and detected or measured by gas chromatography with electron capture detector. Three accidental poisonings are reported: one with carbon tetrachloride, one with trichlorethylene and the last one is a double intoxication with tetrachloroethylene and trichlorethylene.

Chromatography, Gas↗
PubMed1999

In vivo application of intestinal pH measurement using 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF) fluorescence imaging.

Measurement of gastrointestinal intramucosal pH (pHim) has been recognized as an important factor in the detection of hypoxia-induced dysfunctions. However, current pH measurement techniques are limited in terms of time and spatial resolutions. A major advance in accurate pH measurement was the development of the ratiometric fluorescent indicator dye, 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF). This study aimed to set up and validate a fluorescence imaging technique to measure in vivo the intramucosal pH (pHim) of the intestine. The intestine was inserted into an optical chamber placed under a microscope. Animals were injected intravenously with the pH-sensitive fluorescent dye BCECF. Fluorescence was visualized by illuminating the intestine alternately at 490 and 470 nm. The emitted fluorescence was directed to an intensified camera. The ratio of emitted fluorescence at excitation wavelengths of 490 and 470 nm was measured, corrected and converted to pHim by constructing a calibration curve. The pHim controls were performed with a pH microelectrode and were correlated with venous blood gas sampling. Results show that pHim is determined with an accuracy of +/- 0.07 pH units and a response time of 1 min. In conclusion pHim mapping of rat intestine can be obtained by fluorescence imaging using BCECF. This technology could be easily adapted for endoscopic pH measurements.

Animals↗
PubMed1998

Poisoning with methanol and ethylene glycol:1H NMR spectroscopy as an effective clinical tool for diagnosis and quantification.

Analysis of serum and urine samples from three patients in a metabolic acidotic state was performed using biochemical methods and proton nuclear magnetic resonance (1H NMR). Methanol and ethylene glycol were identified by their singlet peaks in the 1H NMR spectra recorded directly from 0.5 ml of the collected samples. Quantification of these compounds was obtained simultaneously with that of their metabolites, formate and glycolate respectively and of lactate and ethanol, the latter being used as an antidote. The NMR results were found to be very similar to the biochemical findings. The results presented here suggest that 1H NMR can be clinically useful since it quickly provides information on the onset of metabolic acidosis and on the biotransformation of xenobiotics.

Acidosis↗
PubMed1998

Lack of a nitric-oxide response during the course of Leishmania infantum infection in the golden hamster (Mesocricetus auratus), with or without treatment with liposomal amphotericin B.

Liver and spleen volumes and serum concentrations of nitrate (the end-product of NO in vivo), albumin, gamma-globulin, protein, creatine and urea were measured during the course of progressive infections with Leishmania infantum MON-1 (MHOM/PR/93/CRE29) in 10 Syrian golden hamsters. Each hamster was infected by intraperitoneal injection with 4 x 10(7) promastigotes. Five of the infected animals were treated, with 6 mg liposomal amphotericin B (L-AmB)/kg given by intracardiac injection, on day 107 post-infection (p.i.). Compared with those in the uninfected hamsters used as controls, the liver volumes in the infected animals became significantly enlarged by day 40 p.i. (38% larger than the controls; P < 0.001) whereas significant enlargement of the spleen was first detected on day 72. Each infected animal had detectable serum levels of antileishmanial antibodies on day 72. There were significant elevations in gamma-globulin concentration as early as day 40 (P < 0.05) but significant falls in albumin concentrations were only detected from day 107 (P < 0.001). Nitrate, creatinine and urea concentrations remained unchanged during the course of infection, even after L-AmB treatment. Serum nitrate levels were not enhanced by L. infantum infection nor by the L-AmB treatment which induced a 98.2% decrease in parasite burden. The lack of NO production in visceral leishmaniasis, with or without L-AmB treatment, points to the unresponsiveness of inducible nitric oxide synthase in this rodent model.

Amphotericin B↗
PubMed1998

Molecular fingerprinting of Mycobacterium tuberculosis and risk factors for tuberculosis transmission in Paris, France, and surrounding area.

Forty-three percent of the tuberculosis cases reported in France are from the Ile de France region. The incidence of tuberculosis in this region is 33 cases per 100,000 inhabitants, twice the national average. A restriction fragment length polymorphism (RFLP) analysis was performed with clinical isolates of Mycobacterium tuberculosis isolated during 1995 in 10 hospitals in Paris and surrounding areas to detect tuberculosis transmission and define the factors associated with clustering in this population. The molecular markers used were the insertion sequence IS6110 and the direct repeat (DR) sequence. Social, demographic, and clinical data were collected from the patients' medical files. Ten patients with isolates with a single copy of IS6110 were excluded from further analysis. Twenty-four patients with false-positive cultures due to laboratory contamination (based on RFLP analysis with IS6110 and examination of patient data) were also excluded. The study was then conducted with 272 strains isolated from 272 patients. Further fingerprinting was performed by using the DR element with strains with patterns by RFLP analysis with IS6110 that differed by one band only and strains with identical patterns by RFLP analysis with IS6110 and with low numbers of copies of IS6110. The combined use of both markers identified unique patterns for 177 strains and clustered 95 (35.7%) strains in 26 groups, each containing isolates from 2 to 12 patients. The clustering was strongly associated with homelessness and the male sex. It was not associated with age, birth in a foreign country, human immunodeficiency virus positivity, or residence in hostels or prison. Isolates from homeless people were often included in large clusters, and homeless people could be the source of tuberculosis transmission for more than 50% of the clustered patients. These results suggest that homeless people play a key role in the spread of M. tuberculosis in the community and that poor socioeconomic conditions are the main risk factors associated with active tuberculosis transmission.

AIDS-Related Opportunistic Infections↗
PubMed1998

[Transluminal treatment of abdominal aortic aneurysms. Might one obstruct the renal arteries?].

During transluminal treatment of an aneurysm of the abdominal aorta, the proximal part of the stent may sometimes lay over the ostia of the renal arteries. Animal studies have shown various scarring patterns depending on the type of stent used and its duration of implantation. The Gianturco and Wallstent appear to be better tolerated than the Palmaz stents. The AA have shown that, with the Strecker stents, a neointima developed between the meshes of the stent over a surface of 43% +/- 30% in 6 weeks. May and Parodi report some occlusions in their clinical series. In the AA's series using Vanguard, no renal artery was thrombosed despite the fact that the stent lay over the artery on 2 occasions in 105 patients. In conclusion, the consequences of the proximal part of a stent laying over the ostium of a renal artery depend mainly on the type of stent used. "Wide mesh" stents are probably the best to use to prevent serious renal complications.

Animals↗
PubMed1997

Diagnosis of a case of acute chloroquine poisoning using 1H NMR spectroscopy: characterisation of drug metabolites in urine.

Analysis of biological fluids by proton nuclear magnetic resonance spectroscopy (1H NMR) is a promising tool in clinical biology. We have used this method for a rapid toxicological screening in the case of a suicide attempt. A urine sample was analysed at 300 and 600 MHz by 1D and 2D sequences (J-resolved and TOCSY) in a short experimental time. Quantification was realized by peak integration of the 1D spectrum. The results showed the presence of chloroquine and its major metabolite monodesethylchloroquine at concentrations of 462 and 140 mg/L, respectively. Ethanol was also detected in the spectrum. It can be concluded that 1H NMR provides many advantages as a tool for clinical diagnosis in a case of acute intoxication.

Acute Disease↗
PubMed1997

Tumoural portal vein thrombosis. Enhancement with MnDPDP.

PURPOSE: Intrahepatic thrombus is usually associated with either cirrhosis or hepatocellular carcinoma (HCC). Most HCCs enhance after the administration of MnDPDP (Teslascan). Our objective was to analyze the enhancement characteristics of tumour portal vein thrombi. MATERIAL AND METHODS: Thrombi affecting the main or segmental portal veins (17 cases) and the suprahepatic inferior vena cava (1 case) were retrospectively selected from a series of 128 patients studied with MR imaging before and after the administration of MnDPDP. Enhancement was assessed qualitatively and quantitatively. RESULTS: All tumour thrombi enhanced after MnDPDP administration. The enhancement was more conspicuous in the GRE images. On the quantitative evaluation, the portal thrombus enhancement was greater for GRE images than SE images. Portal thrombi enhanced more than the liver and the HCCs. There was a significant difference between the enhancement of the HCCs and the thrombi with both MR imaging techniques. CONCLUSION: The greater enhancement of the tumour thrombus associated with the liver and HCC may suggest that other mechanisms, apart from accumulation of the contrast medium within the hepatocytes inside the thrombi, are involved in thrombus enhancement.

Aged↗