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M Meignan

Publications and source records attributed to M Meignan.

At least 37 records · Page 2Linked to original sources
PubMed1995

Management of focal nodular hyperplasia and hepatocellular adenoma in young women: a series of 41 patients with clinical, radiological, and pathological correlations.

Preoperative distinction between focal nodular hyperplasia (FNH) that should be managed conservatively and hepatocellular adenoma (HA) that should be resected remains difficult. The result is controversial management of these patients. The aims of this study were to report the value of modern imaging procedures for noninvasive diagnosis of these lesions, to assess the value of intraoperative frozen section studies, and to propose a management strategy in those patients. Forty-one consecutive women with FNH (35 cases) or HA (6 cases) treated at our institution between 1985 and 1992 were studied. New imaging techniques, including enhanced magnetic resonance imaging (MRI) and color Doppler ultrasonography (US), were prospectively appraised in addition to usual techniques. Histological examination of surgical specimens was obtained in all cases. A sixfold increase in the number of patients with FNH was observed during this study, whereas the number of patients with HA did not change. FNHs were incidental US findings in 74% of the cases. The best imaging procedure in the diagnosis of FNH was enhanced MRI with a sensitivity of 70% and a specificity of 98%. Color Doppler US was a useful adjunct. Intraoperative frozen section studies were performed in 16 patients with 19 tumors with a sensitivity of 89% and a specificity of 100%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma, Liver Cell↗
PubMed1994

Prospective study of pulmonary function for cyclomegalovirus infection after renal transplantation.

Pulmonary involvement remains the main complication of cytomegalovirus (CMV) infection in renal transplantation (RT). Early diagnosis is required for the best management of patients, and preemptive therapy could be a successful approach. In order to define the predictive value of lung alveolocapillary abnormalities. We prospectively studied 26 renal transplant recipients for their diffusing capacity of carbon monoxide (DLCO) and their pulmonary clearance of a 99mTc-DTPA aerosol. Patients were studied before transplantation and then every 2 weeks up to the end of the 3rd month following RT. Viral blood cultures and serological determinations were performed every week during these first 3 months. Bronchoalveolar lavage (BAL) was done in case of CMV disease. Statistic analysis was done using Student's t-test and Pearson's chi-square test. During the 3-month follow-up, 13 patients remained free of CMV infection. Three non-infected and 8 infected patients showed DTPA clearance abnormalities (P < 0.05). Six non-infected and 7 infected patients showed DLCO disturbance (P > 0.50). DTPA clearance were significantly modified on days 45 and 60 in the infected group. Serial DTPA scanning, in association with viral blood cultures, could be a useful test to avoid unnecessary BAL in a preemptive therapy strategy.

Bronchoalveolar Lavage↗
PubMed1994

Alveolar liquid and protein clearance in anesthetized ventilated rats.

Alveolar and lung liquid clearances were studied over 1, 4, and 6 h in intact anesthetized ventilated rats by instillation of 5% albumin solution with 1.5 microCi of 125I-labeled albumin (3 ml/kg into 1 lung or 6 ml/kg into both lungs). Alveolar protein clearance as measured by residual 125I-albumin in the lung over 6 h was similar to the slow rates measured in other species. Alveolar liquid clearance was estimated by the concentration of albumin in the air spaces. After 1 h, this concentration was 7.8 +/- 0.7 g/dl, which was significantly greater than the initial protein concentration of 5.3 +/- 0.2 g/dl (P < 0.05). Amiloride (10(-3) M) inhibited 45% of the basal alveolar liquid clearance, and ouabain (10(-3) M), instilled and intravenously infused (0.004 mg), inhibited 30% of the clearance. beta-Adrenergic agonist instillation increased alveolar liquid clearance to the fastest 1-h rate (48 +/- 3% of instilled volume) that we observed in any intact species. The removal of the instilled fluid from the lung (expressed as lung liquid clearance; 0.96 +/- 0.3 ml/h) was twice as fast as the rate of alveolar and lung liquid clearance reported in the isolated or in situ rat lung models. The rate of alveolar and lung liquid clearance in these intact rats was significantly faster than those in prior studies in dogs and sheep and was similar to the rates in rabbits.

Adrenergic beta-Agonists↗
PubMed1994

Vitamin E does not prevent exercise-induced increase in pulmonary clearance.

It has been observed that sustained exercise results in a prolonged increase in alveolar epithelial permeability, as assessed by the pulmonary clearance rate of aerosolized 99mTc-labeled diethylenetriaminepentaacetate (Lorino et al. J. Appl. Physiol. 67: 2055-2059, 1989). The involvement of lipid peroxidation in this increased permeability was tested in seven nonsmoking volunteers by comparing the exercise-induced increases in pulmonary 99mTc-diethylenetriaminepentaacetate clearance before and after a 3-wk supplementation with oral vitamin E (1,000 IU/day), according to a protocol designed as a single-blind crossover study. The 60-min exercise was performed on a treadmill at a constant load corresponding to 80% of maximal O2 uptake. Administration of vitamin E, a very important antioxidant, did not reduce the exercise-induced increase in lung clearance, suggesting that the exercise-induced increase in lung epithelial permeability does not primarily result from the occurrence of lipid peroxidation in the alveolar membrane. This result thus corroborates the hypothesis of an alteration of the intercellular tight junctions due to the mechanical effects of hyperventilation.

Administration, Oral↗
PubMed1993

Mucosal immunity in primary glomerulonephritis. III. Study of intestinal permeability.

To study the specificity of gut hyperpermeability in primary glomerulonephritis, we investigated intestinal permeability by means of 51Cr-EDTA testing in 20 healthy individuals and in 30 patients with Immunoglobulin A nephropathy (IgA GN), 25 with idiopathic nephrotic syndrome (INS) and 20 with immune complex glomerulonephritis (IC-GN; membranous+membranoproliferative glomerulonephritis). Gut permeability was statistically increased in each patient group versus the controls [controls: 2% (0.4-3.9); IgA GN: 3.25% (0.7-17.70); INS: 3.71% (0.82-10); IC-GN: 3.40% (0.30-16); results are median (range); p < 0.005, nonparametric Mann-Whitney test]. An increase in intestinal permeability exceeding the upper limit of control values (95th percentile) was observed in 36% of IgA GN, 60% of INS and 50% of IC-GN patients. We conclude that intestinal permeability is frequently increased in primary glomerulonephritis and may also be increased in types of glomerulonephritis other than IgA GN.

Adult↗
PubMed1993

The hot spot hepatobiliary scan in focal nodular hyperplasia.

A prospective study was performed on 14 patients with histologically proven focal nodular hyperplasia (FNH) using a hepatobiliary scan with trimethylbromoimino-diacetic acid (TBIDA) and a colloid scan with rhenium sulfur colloids. TBIDA uptake was relatively normal in the region of the tumor, but during the clearance phase 23/25 of the tumors were detected by a hot spot of radioactivity. Depending on the relative contrast achieved between the tumor and normal liver, this hot spot appeared early or later, but was always present at 60 min. In three tumors, a "doughnut" pattern was observed within the hot spot due to a central defect. Hypervascularization was observed during the perfusion phase in 76% of the tumoral sites and normal colloid uptake in only 64%. The detectability of FNH appears greater with TBIDA (92%) than with CT or MRI (84%). The high prevalence of hot spots may be due to careful technological conditions when obtaining hepatobiliary scans. Late images, overexposed films, multiple views and stimulation of gallbladder excretion increased tumor detectability. The hot spot sign may be a useful tool when combined with the results of other imaging modalities in the diagnosis of FNH. The peculiar pathology of FNH with fibrosis, hyperplastic hepatocytes and cholangiolar proliferation might explain this scintigraphic appearance.

Adult↗
PubMed1992

Technetium-99m-DTPA aerosol and gallium-67 scanning in pulmonary complications of human immunodeficiency virus infection.

We retrospectively compared the results of 67Ga chest scans and 99mTc-DTPA aerosol clearance measurements with those of fiberoptic bronchoscopy in 88 patients infected with the human immunodeficiency virus. Of 100 investigations, a pulmonary infection was diagnosed in 39, mainly Pneumocystis carinii pneumonia and a noninfectious disorder was found in 42, mainly Kaposi's sarcoma and lymphocytic alveolitis. Gallium scans and DTPA clearance were abnormal respectively in 74% and 92% of infectious complications, and in 12% and 60% of noninfectious disorders. In 10 cases, DTPA clearance was accelerated, while chest x-ray, arterial blood gases and even gallium scanning were normal. A value of DTPA clearance greater than 4.5%.min-1 was both sensitive and specific for the diagnosis of Pneumocystis carinii pneumonia. The gallium scan was always normal in bronchopulmonary Kaposi's sarcoma. We conclude that in symptomatic patients: (1) DTPA clearance measurements are useful for detecting lung disease when chest x-ray and/or PaO2 are normal and (2) a gallium scan is indicated to distinguish progressive Kaposi's sarcoma from a superimposed second process when radiological abnormalities of pulmonary Kaposi's sarcoma are present.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Effects of platelet-activating factor on lung epithelial permeability in the guinea-pig.

We examined the effects of platelet-activating factor (PAF) on lung epithelial permeability by measuring the clearance of intratracheally administered 99m-technetium-labeled diethylene triamine penta-acetic acid (99mTc-DTPA) in guinea-pigs which were anaesthetised, paralysed and mechanically ventilated. The clearance of the radiolabeled tracer molecule 99mTc-DTPA from airways to the blood was expressed as changes in counts/min corrected for background. For each guinea-pig, 99mTc-DTPA clearance was assessed before and after i.v. PAF administration, when tracheal pressure had returned to near control values. Doses of 10, 50 and 100 ng/kg of PAF caused dose-dependent increases in 99mTc-DTPA clearance of 7 +/- 3%, 38 +/- 7% and 65 +/- 11% respectively. The respective effects of 0.5 mg/kg of the beta 2-adrenergic agonist salbutamol and 0.3 mg/kg of the alpha 1-adrenergic agonist methoxamine on the increase in lung epithelial permeability induced by 50 ng/kg PAF were also studied. Salbutamol significantly reduced the acute bronchoconstrictor effects of PAF, but did not affect the increase in lung epithelial permeability, which was 58 +/- 10%. Conversely, methoxamine significantly enhanced the bronchoconstrictor effects of PAF but inhibited the lung epithelial permeability increase, which was only 10 +/- 13%. In the absence of PAF, salbutamol significantly increased this permeability by 49 +/- 11%, whereas methoxamine alone slightly reduced, it by -11 +/- 4%. These results demonstrate that PAF increases lung epithelial permeability and suggest that vascular surface area recruitment may explain this increase.

Albuterol↗
PubMed1991

Changes in the distribution of ventilation and perfusion associated with separation from mechanical ventilation in patients with obstructive pulmonary disease.

A trial of separation from mechanical ventilation may induce an abnormal respiratory pattern and a maldistribution of ventilation-to-perfusion ratios (VA/Q), especially in patients with chronic obstructive pulmonary disease. This study was designed to assess the effects of three different modes of ventilation on the distribution of global and also regional VA/Q in eight patients with chronic obstructive pulmonary disease recovering from acute respiratory failure who remained dependent on mechanical ventilation after more than 5 days of attempted separation from the ventilator. VA/Q distribution was assessed using the multiple inert gas and isotopic scanning methods after 30 min each of controlled mechanical ventilation (CMV), 10 cmH2O inspiratory pressure support, and spontaneous breathing (SB). Controlled ventilation was provided at a respiratory rate ranging from 12 to 18 breaths per min and a tidal volume of 8 ml.kg-1. In comparison to CMV, SB resulted in a decrease in tidal volume (from 512 +/- 144 to 301 +/- 102 ml, P less than 0.01), and an increase in respiratory rate (from 15.5 +/- 3.2 to 27.3 +/- 15.0 breaths per min, P less than 0.05), which increased dead space (+7.1% of minute ventilation), cardiac output (+36%), and the perfusion to areas of low VA/Q (+8.9% of cardiac output) (P less than 0.05, P less than 0.001, and P less than 0.05, respectively). Isotopic scans revealed a horizontal craniocaudal difference of VA/Q in all modes, with the lowest VA/Q zones at the basal part of the lungs (mean basal VA/Q 0.58 in SB and 1.05 in CMV).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Increased lung epithelial permeability in HIV-infected patients with isolated cytotoxic T-lymphocytic alveolitis.

HIV-related lymphocytic alveolitis is common in HIV-seropositive patients without lung infection or tumor. In some of them a fraction of alveolar lymphocytes are HIV-specific cytotoxic T-lymphocytes (CTL) bearing the CD8 and D44 cell surface markers and capable of killing HIV-infected alveolar macrophages. In order to evaluate the in vivo effect of these CTL on lung function, we measured the pulmonary clearance of aerosolized 99mTc-diethylene triamine penta-acetate (DTPA-CI) on 24 occasions in 22 patients with lymphocytic alveolitis. DTPA-CI has been selected as a highly sensitive test to detect injury of the lung epithelium. In 13 of the patients, we found a high DTPA-CI of 4.56 +/- 2.54%.min-1 (mean +/- SD), suggesting an increase of the epithelial permeability. The lymphocytic alveolitis was then characterized by a high cellularity, a high proportion of lymphocytes (59 +/- 18%), mainly composed of CD8+D44+ T-lymphocytes (149 +/- 109 cells/mm3), which spontaneously exhibited a cytolytic activity against the autologous alveolar macrophages in a standard 51Cr release assay. In the remaining 11 patients, DTPA-CI was normal (less than 1.78%.min-1), lymphocytic alveolitis being characterized by a low number or an absence of CD8+D44+ alveolar lymphocytes (9 +/- 13 cells/mm3) with no significant cytolytic activity. In the whole group, a significant correlation (r = 0.74, p = 0.0004) was found between the DTPA-CI and the number of CD8+D44+ lymphocytes and their cytotoxic activity against alveolar macrophages. Altogether, these results suggest that an injury of the lung epithelium could result from a HIV-specific CTL-induced immunologic conflict.

Adult↗
PubMed1989

Intravenous digital subtraction angiography and lung imaging: compared value in the diagnosis of pulmonary embolism.

In a prospective study, 42 consecutive patients with clinically suspected pulmonary embolism underwent ventilation-perfusion (V-Q) lung imaging and digital subtraction angiography (DSA) concurrently with selective conventional pulmonary angiography (CPA). Thirty-eight studies achieved within 24 hours were reviewed independently by two pairs of observers. The findings were compared using CPA as the gold standard. V-Q lung imaging had a high percentage of indeterminate results, but none were false negative nor false positive. DSA had a lower percentage of indeterminate results but missed four of the 25 positive cases and erroneously affirmed the presence of pulmonary embolism in three cases. Therefore, the authors think that V-Q lung imaging should remain the screening examination of choice for evaluating patients with suspected pulmonary embolism.

Angiography↗
PubMed1989

Zones of increased perfusion (hot spots) on perfusion lung scans: correlation with pulmonary arteriograms.

Perfusion lung scans are occasionally characterized by focal zones of apparent hyperperfusion ("hot spots"). To investigate the frequency and significance of this phenomenon, ventilation-perfusion lung scans and pulmonary arteriograms were reviewed in 72 patients who underwent both procedures for the evaluation of suspected pulmonary embolism. Hot spots were present in the scans of 13 patients and usually occupied less than one pulmonary segment. Most hot spots were detected within a region of atelectasis identified on chest radiographs (38%). A substantial number of the remaining hot spots were located in the lung adjacent to regions of embolus. In patients with massive embolus, hot spots actually represented normally preserved perfusion in the presence of globally reduced perfusion elsewhere.

Adult↗
PubMed1989

Effects of sustained exercise on pulmonary clearance of aerosolized 99mTc-DTPA.

The effects of intensive prolonged exercise on the pulmonary clearance rate of aerosolized 99mTc-labeled diethylenetriaminepentaacetate (99mTc-DTPA) and pulmonary mechanics were studied in seven healthy nonsmoking volunteers. 99mTc-DTPA clearance and pulmonary mechanics (lung volumes and compliance) were assessed before and after 75 min of constant-load exercise performed on a treadmill, corresponding to 75% of maximal O2 uptake. Because both clearance measurements were made in similar conditions of pulmonary blood flow, respiratory rate, and tidal volume, changes in clearance rate can be assumed to represent changes of alveolar epithelial permeability. After exercise, total, apical, and basal clearance were significantly increased (P less than 0.01, 0.05, and 0.05, respectively) and the increases in total clearance and tidal volume observed during exercise were significantly correlated (P less than 0.05). In contrast, no significant change was found in pulmonary mechanics. These results show that prolonged intensive exercise induces an increase in epithelial permeability, which appears to be related to the mechanical effects of sustained increased ventilation. Because no change was evidenced in pulmonary volumes or in lung elasticity, our results suggest that this increase may result from alteration of the intercellular tight junctions rather than from a surfactant deficiency.

Adolescent↗
PubMed1989

Chronic thromboembolic occlusion of main pulmonary artery does not reduce the lung clearance of 99mTc-DTPA.

In two patients with chronic unilateral massive pulmonary embolism, we studied the pulmonary epithelial permeability by measuring the clearance of inhaled and deposited 99mTc-DTPA aerosol. The clearances from the embolized lungs with complete or almost complete occlusion of a main pulmonary artery were more rapid than the clearances from the normal lung, which had an increased blood flow. This suggests that in chronic, embolized lung (1) the bronchial flow clears the inhaled solutes, and (2) there is an increase of epithelial permeability.

Adult↗