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Biomedical subjects

D Mathieu

Publications and source records attributed to D Mathieu.

At least 37 records · Page 2Linked to original sources
PubMed1994

Hepatocellular adenoma: color Doppler US and pathologic correlations.

PURPOSE: To describe the color Doppler ultrasound (US) features of hepatocellular adenoma (HA) and correlate these findings with pathologic findings, with special emphasis on the blood vessels. MATERIALS AND METHODS: Color Doppler US was prospectively performed in eight patients with histologic proof of HA. Eleven lesions were studied. RESULTS: In seven lesions, color Doppler US demonstrated central color flow. In six of these lesions, pulse-wave Doppler US demonstrated a continuous and flat venous spectrum with frequency shifts of 0.20-0.60 kHz (mean, 0.37 kHz), which corresponded to pathologic findings of intratumoral veins 1-5 mm in diameter. The other lesion with central color flow demonstrated a triphasic venous waveform with 1.20-kHz frequency shift, which corresponded pathologically to a central vein 10 mm in diameter. In these seven lesions, color Doppler examination demonstrated both venous and arterial peritumoral flow. CONCLUSION: Color Doppler US enables detection of intratumoral veins associated with peritumoral veins and arteries in patients with HA; these findings correlate well with pathologic data. These results might help in the differential diagnosis of HA and focal nodular hyperplasia.

Adenoma, Liver Cell↗
PubMed1994

MR imaging in acute infectious cellulitis.

PURPOSE: To describe magnetic resonance (MR) imaging findings in acute infectious cellulitis and assess its value for the diagnosis of severe necrotizing forms. MATERIALS AND METHODS: Spin-echo (SE) T1- and T2-weighted imaging was performed in 36 patients with acute infectious cellulitis. T1-weighted SE images obtained after injection of a paramagnetic contrast agent were also obtained when an abscess was suspected on precontrast images. Sixteen patients underwent surgical débridement, along with fascial and muscle biopsy. RESULTS: Distinct MR imaging features were found in patients with necrotizing soft-tissue infections, that is, hyperintense signal on T2-weighted images at the deep fasciae, poorly defined areas of hyperintense signal on T2-weighted images within muscles, and peripheral enhancement on contrast material-enhanced T1-weighted images. In nonnecrotizing cellulitis, signal intensity abnormalities were seen only in the subcutaneous fat. CONCLUSION: The precise extent of acute cellulitis and the presence of necrotizing soft-tissue infections can be determined with MR imaging, particularly on T2-weighted images.

Abdominal Muscles↗
PubMed1994

Diagnostic value of direct examination of the protected specimen brush in ventilator-associated pneumonia.

Interpretation of the protected specimen brush (PSB) technique is based on quantitative bacterial cultures (QC), which unfortunately requires at least 24 h. We prospectively compared the diagnostic value of direct examination (DE) and QC of PSB specimens in 75 patients with suspected pneumonia. We also determined the optimal technique for DE. QC was performed using the serial dilution technique. From the original suspension, two cytospin slides were obtained and stained by the May-Grünwald Giemsa (MGG) and the Gram method for DE. If the prescreening on the MGG-stained slide was positive, the morphology and the Gram staining of the organisms were assessed on the Gram-stained slide. Using the 10(3) colony forming units (cfu.ml-1) threshold for defining PSB as positive or negative, DE had a sensitivity of 85% and a specificity of 94%. In a parallel in vitro study, 18 pairs of PSB specimens were collected from respiratory secretions inoculated with S. aureus. From each pair, one brush was processed as described above and the other was smeared on a glass slide prior to performance of QC. Using direct smear instead of cytocentrifuged preparation, slightly but significantly affected QC. Direct examination of cytospin slides is highly predictive of quantitative bacterial culture results, and provides rapid information regarding the Gram-stain morphology of the causative organisms. It may therefore guide initial therapy.

Adolescent↗
PubMed1994

Prognostic value of early computed tomographic scans in severe acute pancreatitis. French Association for Surgical Research.

BACKGROUND: The prognostic value of computed tomographic (CT) scans in differentiating mild from severe forms of acute pancreatitis is well established. Nonetheless, in patients with a severe form of the disease, some will have a relatively uneventful course while others will have severe complications. This prospective, multicenter study was done to evaluate the prognostic value of early CT scan in a homogenous group of patients with a first attack of severe acute pancreatitis. STUDY DESIGN: Dynamic CT scans were performed within 48 hours after admission. A standardized form was completed for each CT scan, recording the following data: abnormal enhancement of the pancreas itself, characteristics of extrapancreatic collections, and visualization of the portal and splenic veins. Statistical analysis was based on the log rank test and Cox's model and used death and abscess occurrence as the two end points. RESULTS: Two hundred twenty-eight patients from 46 centers were included in the study. The median Ranson and Imrie scores were 3 and 4, respectively. Forty-seven patients died and 72 had an abscess. The CT scan findings indicating an increase in mortality rate were nonenhancement of the neck of the pancreas (p = 0.04) and extrapancreatic collections within the left (p = 0.001) and right (p = 0.02) pararenal posterior spaces. The risk of abscess increased when there was nonvisualization of the splenic vein (p = 0.0001), in the presence of extrapancreatic collections in the right pararenal posterior space (p = 0.03) and when the extrapancreatic collections were heterogenous (p = 0.003). CONCLUSIONS: This study demonstrated that the location of extrapancreatic collections and nonvisualization of the splenic and portal veins on CT scans were not previously recognized prognostic factors of complicated outcome in patients with severe acute pancreatitis.

Abdominal Abscess↗
PubMed1993

New latex reagent using monoclonal antibodies to capsular polysaccharide for reliable identification of both oxacillin-susceptible and oxacillin-resistant Staphylococcus aureus.

A new latex agglutination test (Pastorex Staph-Plus, Sanofi Diagnostics Pasteur), consisting of a mixture of latex particles coated with fibrinogen and immunoglobulin G for the detection of clumping factor and protein A and latex particles sensitized with monoclonal antibodies directed to Staphylococcus aureus serotype 5 and 8 capsular polysaccharides, was compared with three commercially available rapid agglutination methods for the identification of 220 isolates of S. aureus (61 oxacillin resistant) and 128 isolates of coagulase-negative staphylococci. The sensitivity for identification of S. aureus was high with the Pastorex Staph-Plus test (98.6%) compared with those of the other tests, which ranged from 91.8 to 84.5%. Test sensitivities for the identification of oxacillin-resistant S. aureus were as follows: Pastorex Staph-Plus, 95.1%; Pastorex Staph, 73.8%; Staphyslide, 72.1%; and StaphAurex, 49.2%.

Antibodies, Monoclonal↗
PubMed1993

Focal nodular hyperplasia of the liver: value of color Doppler US in association with MR imaging.

Seventeen patients with 19 lesions of focal nodular hyperplasia (FNH) underwent prospective examination with color Doppler ultrasound (US) and magnetic resonance (MR) imaging. In 13 lesions, color Doppler US demonstrated central spots with an arterial Doppler spectrum. The frequency shifts ranged from 1.02 to 1.94 kHz (mean, 1.56 kHz). On flow-sensitive unenhanced gradient-echo images, hyperintense central dots were depicted in only five of these 13 lesions. All the MR features of FNH were present in 12 lesions. Among the seven lesions without all of the MR features, central color spots were present with an arterial Doppler spectrum in four lesions. In the remaining three lesions, color Doppler examination demonstrated either peritumoral pulsatile flow (two lesions) or no flow (one lesion). Color Doppler US adds information about the intratumoral flow characteristics of this vascular malformative lesion and appears to be superior to MR imaging in detection of the arterial intratumoral abnormalities.

Adult↗
PubMed1993

Diagnosis of pneumonia in mechanically ventilated patients. Repeatability of the protected specimen brush.

The repeatability (i.e., the variation in repeated measurements of the same quantity) of the protected specimen brush (PSB) with quantitative cultures was assessed in 22 consecutive mechanically ventilated (MV) patients with suspected nosocomial pneumonia. Five PSB samples were collected in the same lung area during the same bronchoscopic procedure and processed for bacteriologic identification and quantitative culture. A laboratory control was also performed in order to assess the in vitro repeatability of the quantitative culture technique. The five PSB always recovered the same microorganisms, indicating a 100% qualitative repeatability for the PSB. Conversely, the quantitative repeatability was somewhat lower since in 59% of the patients the quantitative results varied by more than one log10, which is the minimal precision affordable with quantitative cultures. The distinction between presence or absence of infection based on the 10(3) cfu/ml recommended diagnostic threshold was, however, only moderately affected by the variability of the quantitative results since only three of 22 patients (13.6%) displayed results spread out on each side of the 10(3) cfu/ml break point. Intrasubject variability of quantitative results was not explained by problems with the quantitative culture technique, which proved excellent repeatability in the laboratory. This study indicated that, although the PSB technique with quantitative cultures displays an acceptable level of repeatability, caution is advisable when interpreting PSB results in critically ill patients with suspected pneumonia, especially if one refers to the 10(3) cfu/ml recommended diagnostic threshold and if a decision to treat or to abstain from treating is to be made.

Bacteria↗
PubMed1993

Diagnostic efficiency of endotracheal aspirates with quantitative bacterial cultures in intubated patients with suspected pneumonia. Comparison with the protected specimen brush.

The objectives of the study were to determine the agreement between the protected specimen brush technique (PSB) with quantitative cultures and endotracheal aspirates (EA) with quantitative cultures when using increasing interpretative cutoff points and to investigate the respective operating characteristics for the diagnosis of pneumonia of PSB and EA when using quantitative cultures. Consecutive sampling of respiratory secretions using these two techniques was conducted in the respiratory intensive care units in 52 mechanically ventilated patients with clinical and radiologic suspicion of pneumonia. Quantitative bacterial cultures of PSB and EA samples were obtained. The 10(6) cfu/ml cutoff point was the most accurate diagnostic threshold for the EA technique. When using this threshold, there was a high level of agreement (84.6%) between PSB and EA results. Among the few discrepancies, the EA result was always indicative of pneumonia, whereas the PSB result was nonindicative, thus permitting us to classify correctly five patients in whom pneumonia would have been erroneously excluded on the basis of the sole result of PSB. Conversely, there was no case where the PSB result was indicative of pneumonia when the EA result (at the 10(6) cfu/ml level) was not. The operating characteristics of the PSB technique for the diagnosis of pneumonia were in accordance with previously published studies. The operating characteristics of the EA technique (when taking the 10(6) cfu/ml of respiratory secretions as the interpretative cutoff point) compared favorably with those of the PSB technique. Diagnostic accuracy rates were similar. The specificity of EA was somewhat lower (83 versus 96%), but the sensitivity was higher (82 versus 64%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Protected specimen brush in the assessment of ventilator-associated pneumonia. Selection of a certain lung segment for bronchoscopic sampling is unnecessary.

The protected specimen brush (PSB) with quantitative cultures is one of the most reliable techniques for assessing pneumonia in mechanically ventilated (MV) patients. The need to select a certain lung segment for bronchoscopic sampling is still debated. We investigated whether the results of PSB specimens collected within an area radiographically involved with pneumonia (inv-PSB) differed from the results of PSB specimens collected within a lung area without radiographic abnormalities (non-inv-PSB) in 39 MV patients with suspected pneumonia. The comparison of bacterial titers of inv-PSB and non-inv-PSB cultures did not disclose significant differences. Agreement regarding the diagnosis of pneumonia according to recommended diagnostic threshold was observed in 34 of 39 patients (87.1 percent). These results which are in accordance with the pathophysiology of ventilator-associated pneumonia and histologic studies do not support the need to select a certain lung segment for bronchoscopic sampling in most MV patients with suspected pneumonia.

Acinetobacter Infections↗
PubMed1993

Detection of multiple myeloma involving the spine: efficacy of fat-suppression and contrast-enhanced MR imaging.

OBJECTIVE: To determine the efficacy of fat-suppressed sequences and contrast-enhanced MR imaging for the detection of focal spinal lesions caused by multiple myeloma, we obtained MR images in 32 patients with newly diagnosed myeloma who had back pain. SUBJECTS AND METHODS: All patients had biopsy-proved myeloma and had MR imaging at the painful level of the spine. Spin-echo T1-weighted, T2-weighted, and short TI inversion-recovery (STIR) images; dynamic ultrafast low-angle shot (turbo-FLASH) images after IV injection of a bolus of paramagnetic contrast material; and contrast-enhanced T1-weighted images were obtained. We qualitatively compared the signal intensities and contrast enhancement of focal lesions with those of the surrounding vertebral bodies. RESULTS: Multiple lesions were detected in all but two of the 32 patients. On T2-weighted and STIR images, all lesions had homogeneously high signal intensity. On T1-weighted images, the lesions were visible as hypointense areas compared with surrounding bone in all except four patients, in whom the lesions were isointense or hyperintense. All tumor nodules enhanced on turbo-FLASH images obtained in the arterial phase. No additional lesions were seen on STIR or contrast-enhanced images. MR findings resulted in a change in the staging of the disease in one patient and led to prompt treatment in five patients with epidural involvement. CONCLUSION: MR imaging appears to be helpful in detecting spinal involvement in patients with multiple myeloma. The diagnosis of spinal lesions is best achieved by using either fat-suppressed or T2-weighted images. Although myeloma lesions enhanced in all patients, contrast material appears to be of no value for the detection of additional lesions.

Contrast Media↗
PubMed1993

MR appearance of multiple myeloma of the spine before and after treatment.

OBJECTIVE: The aim of this study was to describe the changes in the MR appearance of painful lesions of the spine before and after treatment in 18 patients with multiple myeloma and to correlate these changes with the clinical response to treatment. SUBJECTS AND METHODS: Eighteen patients with multiple myeloma and tumor nodules in the spine had MR imaging of the same site in the spine before and after treatment. Unenhanced T1- and T2-weighted spin-echo images, dynamic ultrafast low-angle shot (turbo-FLASH) images before and after IV bolus injection of paramagnetic contrast material, and contrast-enhanced T1-weighted spin-echo images were obtained. Characteristic signal and contrast enhancement before and after treatment were compared and were correlated with clinical data and the results of immunochemical and pathologic tests. RESULTS: Changes in signal intensity and enhancement of the lesions occurred after treatment in 14 of 18 patients. The characteristics of the lesions after treatment had three patterns: (1) rim enhancement or no enhancement of the lesions, (2) early enhancing lesions associated with other nonenhancing lesions or lesions with rim enhancement, and (3) no change from the enhancement pattern seen before treatment. In 13 of 18 patients, these patterns correlated well with the response to treatment. A discrepancy was observed in five patients. CONCLUSION: The MR appearance of spinal myeloma is different before and after treatment. MR images, particularly contrast-enhanced images, may be helpful in monitoring the response to treatment of focal bone lesions of myeloma.

Combined Modality Therapy↗
PubMed1993

Atrazine in plasma and tissue following atrazine-aminotriazole-ethylene glycol-formaldehyde poisoning.

A high performance liquid chromatography method has been used to study the plasma kinetics of atrazine in a human fatality after ingestion of a herbicide mix containing atrazine, aminotriazole, ethylene glycol and formaldehyde. A hemodialysis was performed in an effort to eliminate these toxic substances. The mean atrazine clearance over 4 h was 250 mL/min and the dialysance of atrazine was calculated as 76%. On autopsy, the kidney showed the highest concentration of atrazine (97.62 micrograms/g-1 wet tissue) with lesser concentrations in the lung, small intestine and liver, and the lowest concentration in the heart.

Adult↗
PubMed1993

Pedicle musculocutaneous flap transplantation: prediction of final outcome by transcutaneous oxygen measurements in hyperbaric oxygen.

In pedicle musculocutaneous flaps, a local circulatory insufficiency with a total or subtotal ischemia may occur and jeopardize the result of the reconstructive surgery. Transcutaneous oxygen pressure (PtcO2) monitoring has been shown to reflect tissue perfusion and has been advocated to predict the final outcome of ischemic flaps. Unfortunately, under normal atmospheric conditions, this test is not sufficiently discriminative. We evaluate the effect of hyperbaric oxygen conditions on the efficiency of this test. Fifteen patients with pedicle musculocutaneous flap were evaluated by clinical examination and transcutaneous oxygen tension measurements. The final outcome was healing in 7 and failure in 8. In order to determine the predictive value of transcutaneous oxygen tension, measurements were done immediately after the surgical procedure. In ambient air, neither the absolute value of transcutaneous oxygen tension (2.6 +/- 3.6 versus 11.7 +/- 12.6 torr; N.S.) nor the difference or the ratio between the transcutaneous oxygen tension of the flap and the subclavicular reference shows any significant difference according to the outcome (failure or success). The same is true in normobaric oxygen. In hyperbaric oxygen, however, there is a significant difference in transcutaneous oxygen tension between the two groups (12 +/- 12 versus 378 +/- 385 torr; p < 0.01). A transcutaneous oxygen tension higher than 50 torr in hyperbaric oxygen (2.5 atm abs) is the best cutoff value to discriminate success from failure.

Adult↗
PubMed1992

[Liver transplantation associated with combined adjuvant treatment in hepatocellular carcinoma. Feasibility and preliminary results].

Combined adjuvant therapy was prospectively assessed in 7 patients receiving orthotopic liver transplantation for hepatocellular carcinoma complicating cirrhosis. The protocol included hepatic arterial chemotherapy while waiting for transplant, immediate preoperative liver irradiation, and early postoperative chemotherapy. There were no postoperative deaths, and morbidity included mainly hematologic toxicity of chemotherapy. Two patients died of tumor recurrence 6 and 14 months after transplant. The remaining 5 patients are alive and free of disease with a follow-up of 7 to 26 months. These results show the feasibility of aggressive adjuvant therapy in patients transplanted for hepatocellular carcinoma and suggest a possible effect of such a protocol on the prevention of tumor recurrence.

Adult↗