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Biomedical subjects

B Maitre

Publications and source records attributed to B Maitre.

At least 19 recordsLinked to original sources
PubMed2003

[Impact of prior biological assessment of coagulation on the hemorrhagic risk of fiberoptic bronchoscopy].

INTRODUCTION: The goals of the study were to test the value of coagulation tests to predict bleeding events during fiberoptic bronchoscopy (FOB) and to identify risk factors. METHODS: A monocentric prospective study of 426 procedures performed by one physician was realized. A standardized questionnaire and coagulation tests including prothrombine time, activated cephaline time and platelets counts were performed before the procedure. Bleeding events, defined by a loss of more than 50 ml of blood, were recorded for all patients. RESULTS: 44 patients (10.3%) had bleeding events, modifying the procedure in 19 cases. No death occurred following FOB during the study. Among the 17 patients with abnormalities on coagulation test before FOB, only one had significant bleeding. Two risk factors were found as predictors of bleeding events: nose or gum bleeding (OR=4.99, CI (95%) [2.6-9.5]; p<0.001) and left cardiac failure (OR=4.53, CI (95%) [1.7-12.1]; p<0.01). CONCLUSION: This study shows that abnormalities on coagulation tests are not predictive for bleeding events. Nose or gum bleeding and left cardiac failure may be risk factors for bleeding events during FOB.

Adolescent↗
PubMed2001

[Update in pneumology].

The end of the century has not brought any great modification in pneumology therapy. Prospective studies in asthma using combined therapeutic approaches, systemic or local steroid treatment in mild or moderate chronic obstructive pulmonary disease or itraconazole in allergic bronchopulmonary aspergillosis are summarized in this review. Innovation is coming from radiology, with confirmation of the interest of positive-emission tomography for the preoperative stage of lung cancer.

Adult↗
PubMed2001

Vascular endothelial growth factor synthesis in the acute phase of experimental and clinical lung injury.

Vascular endothelial growth factor (VEGF) is a potent angiogenic and endothelial survival factor, which is abundantly expressed in the normal lung. Conceivably, VEGF may be released by numerous cell types found around the airspaces, including alveolar type 2 cells, alveolar macrophages, and polymorphonuclear neutrophils. Using a bacteria-induced lung injury model in rats, VEGF expression in lung was investigated. Both VEGF protein and VEGF messenger ribonucleic acid (mRNA), 4 and 24 h after bacterial challenge (Pseudomonas aeruginosa), were decreased compared with sham rats. VEGF protein was also investigated in bronchoalveolar lavage (BAL) from patients studied within 7 days of acute respiratory distress syndrome (ARDS) onset and in patients without ARDS. VEGF protein levels in BAL were decreased in patients with ARDS versus those without (14.3 +/- 11.1 pg x mL(-1) versus 76.8 +/- 51.1 pg x mL(-1), p = 0.03). In aggregate, these findings show that the initial phase of acute lung injury is associated with a decrease in vascular endothelial growth factor in the lung. This downregulation may represent a protective mechanism aimed at limiting endothelial permeability, and may participate in the decrease in capillary number that is observed during early acute respiratory distress syndrome.

Animals↗
PubMed2001

[Lyme disease presenting as infarction pain. A case report].

Lyme's disease is a multi-system condition due to infection with a spirochete (Borrelia Burgdorferi), transmitted by a tick. Cardiac involvement, which is not systematic, usually presents with transient atrioventricular block of varying degree. The authors describe an unusual presentation of the cardiac involvement of Lyme's disease with chest pain resembling an acute coronary syndrome in a 32 year old man. The characteristic skin lesion (erythema migrans), the positivity of IgM serology, the myocardial scintigraphic results and the negativity of the work-up of other causes of this pain led to a diagnosis of myocarditis, the outcome of which was favourable with treatment by amoxycillin (3 g/day, orally).

Adult↗
PubMed2000

Traumatic coronary-pulmonary artery fistula, 23 years after a stab wound.

We describe a 50-year-old man with onset of severe hemoptysis and anemia. Twenty-three years earlier, he had undergone a surgical procedure for a left thoracic wound as a result of a knife injury. Current diagnosis of aneurysm of the left ventricle and coronary-pulmonary artery fistula was made after coronary arteriography. The patient underwent resection of the aneurysm and repair of the fistula.

Arterio-Arterial Fistula↗
PubMed2000

Unusual case of diagnosis of pigeon breeder's hypersensitivity pneumonitis with ventilation-perfusion lung scan.

The authors describe a patient thought to have pulmonary embolism. Results of a perfusion scan were normal, but Tc-99m DTPA aerosol ventilation lung scan showed, in successive views, decreased activity of the deposited aerosol. The lung Tc-99m DTPA clearance was measured and was markedly increased. This suggested possible hypersensitivity pneumonitis, which was later confirmed as pigeon breeder's disease. The decreased activity observed on the DTPA ventilation scan must be directed toward increased lung clearance and its measurement.

Administration, Inhalation↗
PubMed2000

Role of adhesins and toxins in invasion of human tracheal epithelial cells by Bordetella pertussis.

Bordetella pertussis, the agent of whooping cough, can invade and survive in several types of eukaryotic cell, including CHO, HeLa 229, and HEp-2 cells and macrophages. In this study, we analyzed bacterial invasiveness in nonrespiratory human HeLa epithelial cells and human HTE and HAE0 tracheal epithelial cells. Invasion assays and transmission electron microscopy analysis showed that B. pertussis strains invaded and survived, without multiplying, in HTE or HAE0 cells. This phenomenon was bvg regulated, but invasive properties differed between B. pertussis strains and isolates and the B. pertussis reference strain. Studies with B. pertussis mutant strains demonstrated that filamentous hemagglutinin, the major adhesin, was involved in the invasion of human tracheal epithelial cells by bacteria but not in that of HeLa cells. Fimbriae and pertussis toxin were not found to be involved. However, we found that the production of adenylate cyclase-hemolysin prevents the invasion of HeLa and HTE cells by B. pertussis because an adenylate cyclase-hemolysin-deficient mutant was found to be more invasive than the parental strain. The effect of adenylate cyclase-hemolysin was mediated by an increase in the cyclic AMP concentration in the cells. Pertactin (PRN), an adhesin, significantly inhibited the invasion of HTE cells by bacteria, probably via its interaction with adenylate cyclase-hemolysin. Isolates producing different PRNs were taken up similarly, indicating that the differences in the sequences of the PRNs produced by these isolates do not affect invasion. We concluded that filamentous hemagglutinin production favored invasion of human tracheal cells but that adenylate cyclase-hemolysin and PRN production significantly inhibited this process.

Adenylate Cyclase Toxin↗
PubMed2000

Expression and regulation of vascular endothelial growth factor in human pulmonary epithelial cells.

Vascular endothelial growth factor (VEGF) is a potent endothelial cell growth and permeability factor highly expressed in rodent alveolar epithelium after injury and repair. To investigate VEGF synthesis in human lung epithelial cells, we examined VEGF expression by cultured cells under basal conditions and after cytokine treatment or oxidative stress. Basal VEGF expression was detected in transformed human epithelial cell lines (A549 and 1HAEo-) and in primary human bronchial epithelial cells with RT-PCR, Western blot, and immunocytochemistry. Among the cytokines tested, only transforming growth factor-beta1 increased the levels of excreted VEGF(165) as measured by ELISA. Under hypoxia (0% O(2) for 24 h), the VEGF(165) level increased fivefold, and this effect was O(2) concentration dependent. VEGF concentrations in the medium of all the cell types studied reached values similar to those found in bronchoalveolar lavage fluids from normal patients. Endothelial cells (human umbilical vein endothelial cells) exposed to conditioned medium from primary bronchial epithelial cell cultures showed an increased growth rate, which was inhibited in the presence of a specific neutralizing antibody to VEGF. These results suggest that lung epithelial cells participate in the endothelial repair and angiogenesis that follow lung injury through the synthesis of VEGF.

Bronchoalveolar Lavage Fluid↗
PubMed2000

Continuous positive airway pressure during fiberoptic bronchoscopy in hypoxemic patients. A randomized double-blind study using a new device.

Fiberoptic bronchoscopy (FOB) may worsen oxygenation and clinical status in severely hypoxemic patients. We conducted a prospective, randomized double-blind trial to compare the delivery of continuous positive airway pressure (CPAP) as a tool for maintaining oxygenation during FOB, to the delivery of oxygen only. Thirty consecutive patients who needed FOB for diagnostic purposes were enrolled. Their arterial oxygen pressure (Pa(O(2))) to inspired oxygen fraction (FI(O(2))) ratio was below 300 mm Hg. CPAP was generated by a simple new device open to the atmosphere. During FOB and the 30 min thereafter, pulse oximetry values (Sp(O(2))) were significantly higher in the CPAP than the Oxygen group (95.7 +/- 1.9% versus 92.6 +/- 3.1, p = 0.02). The lowest Sp(O(2)) values were observed in the Oxygen group (93.5 +/- 2.4% versus 88.6 +/- 3.4, p = 0.002). Arterial blood gases 15 min after FOB showed that Pa(O(2)) had increased in the CPAP group and decreased in the Oxygen group (DeltaPa(O(2)) = +10.5% +/- 16.9 versus -15% +/- 16.6, p = 0.01). Five patients in the Oxygen group, but none in the CPAP group, developed respiratory failure in the 6 h after FOB and required ventilatory assistance (p = 0.03). We conclude that in hypoxemic patients, the use of a new CPAP device during FOB allowed minimal alterations in gas exchange and prevented subsequent respiratory failure.

Adult↗
PubMed2000

Acute chest syndrome in adults with sickle cell disease.

STUDY OBJECTIVES: Acute chest syndrome (ACS) is a frequent and potentially severe pulmonary illness in sickle cell disease (SCD). The aim of the study was to report the clinical features and outcome of consecutive ACS episodes in adult patients in a French SCD center. All patients were treated according to an uniform therapeutic protocol applying transfusion only in the more severe clinical form of ACS. RESULTS: There were 107 consecutive episodes in 77 adult patients (mean age, 29 +/- 7 years; 78% hemoglobin [Hb] SS; 14% Hb SC; and 8% Hb Sbeta + thalassemia) over a 6-year period. Seventy-eight percent of our patients had an associated vaso-occlusive crisis that preceded the chest signs in half of the cases. Comparison between acute and baseline levels showed a statistically significant difference in Hb levels (drop of 1.6 to 2. 25 g/dL depending on Hb genotype), WBC count (increase of 9.2 +/- 8. 3 x 10(9)/L); platelet count (increase of 67 +/- 209 x 10(9)/L); and lactate dehydrogenase values (increase of 358 +/- 775 IU/L) in ACS patients. Hypercapnia was detected in 42% of patients without sign of narcotic abuse. We identified a high percentage of alveolar macrophages containing fat droplets in 31 of 43 (77%) patients who underwent BAL. Bacterial culture findings were almost always negative, but were performed after starting antibiotic therapy that was administered in 96 episodes. Transfusion was required in 50 of 107 ACS events (47%). Five patients died, and all were transfused. CONCLUSIONS: These results confirm that fat embolism is probably a frequent mechanism of ACS in adult patients. However, fat embolism was not associated with a more severe clinical course, suggesting that bronchoscopy and BAL have little impact on the management of these patients. Restricting transfusion to the most severe ACS cases does not seem to increase the mortality rate.

Acute Disease↗
PubMed2000

[Evaluation of occupational exposures in lung cancer].

Occupational lung cancers are underestimated by the number of cases compensated in the French National Insurance System. Rules of compensation of occupational diseases were recently modified in France. Therefore a study was conducted on incident cases of lung cancer in a general hospital in the Paris area. The aim was to evaluate the exposure to carcinogens using data of a detailed specific occupational questionnaire, and to determine the number of cases who could receive compensation. Two hundred and seven subjects (171 males, 36 females, mean age = 64.5 years) were eligible in 1996, and 122 had an occupational questionnaire. Definite exposure to one or more occupational carcinogens in at least one job was identified in 50 subjects, the most frequent agent was asbestos (42 subjects). Claim for compensation was done in 32 subjects, mainly for asbestos (30 subjects). This study emphasizes the frequency of occupational exposure to carcinogens, and the usefulness of systematic occupational questionnaire in subjects having lung cancer. Social and financial consequences are important for these subjects. Further studies are needed, with recruitement of control subjects to allow calculation of the attributable risk to occupational factors in lung cancer.

Aged↗
PubMed1999

Ethylene-regulated gene expression in tomato fruit: characterization of novel ethylene-responsive and ripening-related genes isolated by differential display

Differential display was used to isolate early ethylene-regulated genes from late immature green tomato fruit in order to obtain a broader understanding of the molecular basis by which ethylene coordinates the ripening process. Nineteen novel ethylene-responsive (ER) cDNA clones were isolated that fell into three classes: (i) ethylene up-regulated (ii) ethylene down-regulated, and (iii) transiently induced. Expression analysis revealed that ethylene-dependent changes in mRNA accumulation occurred rapidly (15 min) for most of the ER clones. The predicted proteins encoded by the ER genes are putatively involved in processes as diverse as primary metabolism, hormone signalling and stress responses. Although a number of the isolated ER clones correspond to genes already documented in other species, their responsiveness to ethylene is described here for the first time. Among the ER clones sharing high homology with regulatory genes, ER43, a putative GTP-binding protein, and ER50, a CTR1-like clone, are potentially involved in signal transduction. ER24 is homologous to the multi-protein bridging factor MBF1 involved in transcriptional activation, and finally, two clones are homologous to genes involved in post-transcriptional regulation: ER49, a putative translational elongation factor, and ER68, a mRNA helicase-like gene. Six ER clones correspond to as yet unidentified genes. The expression studies indicated that all the ER genes are ripening-regulated, and, depending on the clone, show changes in transcript accumulation either at the breaker, turning, or red stage. Analysis of transcript accumulation in different organs indicated a strong bias towards expression in the fruit for many of the clones. The potential roles for some of the ER clones in propagating the ethylene response and regulating fruit ripening are discussed.

Journal Article↗