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Biomedical subjects

O Menard

Publications and source records attributed to O Menard.

14 recordsLinked to original sources
PubMed2000

Modeling maps by using rational functions

Rational functions are not very useful for obtaining global differential models because they involve poles that may eject the trajectory to infinity. In contrast, it is here shown that they allow one to significantly improve the quality of models for maps. In such a case, the presence of poles does not involve any numerical difficulty when the models are iterated. The models then take advantage of the ability of rational functions to capture complicated structures that may be generated by maps. The method is applied to experimental data from copper electrodissolution.

Journal Article↗
PubMed1996

Cytokines in human lung fibrosis.

Fibrosis is a pathological process characterized by the replacement of normal tissue by mesenchymal cells and the extracellular matrix produced by these cells. The sequence of events leading to fibrosis of an organ involves the subsequent processes of injury with inflammation and disruption of the normal tissue architecture, followed by tissue repair with accumulation of mesenchymal cells in the area of derangement. The same sequence of events occurs in wound healing with normal granulation tissue and scar formation, but, while normal scar formation is very localized and transient, in contrast, in fibrosis, the repair process is exaggerated and usually widespread and can be chronic. Inflammatory cells (mainly mononuclear phagocytes), platelets, endothelial cells, and type II pneumocytes play a direct and indirect role in tissue injury and repair. The evaluation of three human fibrotic lung diseases, two diffuse [idiopathic pulmonary fibrosis (IPF), and the adult respiratory distress syndrome (ARDS)], and one focal (tumor stroma in lung cancer), has shown that several cytokines participate to the local injury and inflammatory reaction [interleukin-1 (IL-1), interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-alpha)], while other cytokines are involved in tissue repair and fibrosis [platelet-derived growth factor (PDGF), insulin-like growth factor-1 (IGF-1), transforming growth factor-beta (TGF-beta), and basic-fibroblast growth factor (b-FGF)]. A better understanding of the cytokines and cytokine networks involved in lung fibrosis leads to the possibility of new therapeutic approaches.

Cytokines↗
PubMed1996

The role of cytokines in human lung fibrosis.

Fibrosis is a disorder characterized by a qualitative and quantitative alteration of the deposition of extracellular matrix with accumulation of mesenchymal cells in replacement of normal tissue. The sequence of events leading to fibrosis of an organ involves the subsequent processes of injury with inflammation and disruption of the normal tissue architecture, followed by tissue repair with accumulation of mesenchymal cells in this area. A similar sequence of events occurs in wound healing with formation of normal, limited and transient granulation tissue, while in fibrosis, a maladaptive repair leads to an extensive, exaggerated process with functional impairment. Inflammatory cells (mainly mononuclear phagocytes), platelets, endothelial cells, and type II pneumocytes play a direct and indirect role in tissue injury and repair. The evaluation of several human fibrotic lung diseases, five diffuse (idiopathic pulmonary fibrosis (IPF); adult respiratory distress syndrome (ARDS); coal workers' pneumoconiosis (CWP); Hermansky-Pudlak syndrome (HPS); systemic sclerosis (SS)) and two focal (tumour stroma in lung cancer; and obliterative bronchiolitis (OB) after lung transplantation), has shown that several cytokines participate in the local injury and inflammatory reaction (interleukin-1 (IL-1), interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1), and tumour necrosis factor-alpha (TNF-alpha)), while other cytokines are involved in tissue repair and fibrosis (platelet-derived growth factor (PDGF), insulin-like growth factor-1 (IGF-1), transforming growth factor-beta (TGF-beta), and basic-fibroblast growth factor (b-FGF)). A better understanding of the cytokines and cytokine networks involved in lung fibrosis leads to the possibility of new therapeutic approaches.

Cytokines↗
PubMed1995

Association of histologically proven rheumatoid arthritis with pulmonary sarcoidosis.

The association of rheumatoid arthritis proven by means of synovial biopsy with pulmonary sarcoidosis proven by means of bronchial biopsy, occurred in a 58 year old woman. Corticosteroid therapy resulted in complete resolution of sarcoidosis but only slight improvement of the rheumatoid arthritis, which was secondarily treated with methotrexate with a successful outcome. Only two similar cases have been reported with simultaneous histological proofs of both diseases.

Arthritis, Rheumatoid↗
PubMed1994

Intrapleural treatment with recombinant gamma-interferon in early stage malignant pleural mesothelioma.

BACKGROUND: This report presents the results of a prospective multi-institutional study of intrapleural treatment with gamma-interferon in patients with Butchart's Stages I and II epithelial or mixed malignant pleural mesothelioma. METHODS: Interferon was administered at a dose of 40 million units twice a week for 8 weeks intrapleurally via a catheter or an implantable port. Thoracoscopic or surgical biopsy was performed if computed tomography scan 2 weeks after the end of treatment demonstrated a reduction in tumor size. Survival was calculated after a follow-up of at least 18 months. Prognostic factors were identified by univariate and multivariate analyses (Cox model). RESULTS: Eighty-nine patients were included over 46 months. Eight histologically confirmed complete responses and nine partial responses with at least a 50% reduction in tumor size were obtained. The overall response rate was 20%. Most responses were achieved in patients with early stage disease. The response rate for patients with Stage I disease was 45%. Tolerance of interferon was good. Treatment was performed on an outpatient basis. The main side effects were hyperthermia, liver toxicity, neutropenia, and catheter-related infection. CONCLUSIONS: Gamma-interferon is effective mainly in Stage I mesothelioma, especially if the tumor is confined to the parietal or diaphragmatic pleura (Stage IA).

Aged↗
PubMed1993

Improvement of the diagnosis of the cause of pleural effusion in patients with lung cancer by simultaneous quantification of carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) pleural levels.

Carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) level determinations were carried out by radioimmunoassay in pleural fluid and plasma samples obtained from 24 patients with malignant pleural effusions and 18 patients with non-malignant pleural effusions, and compared to cytological and pathological results. Using a pathological cut-off level of 25 ng/ml for CEA and 8 ng/ml for NSE, we demonstrated that, in the diagnosis of the malignant nature of pleural effusions, the simultaneous quantification of CEA and NSE in pleural fluid possesses better discriminative values than the simultaneous quantification of both markers in plasma or the separate quantification of each marker, in pleural fluid and in plasma.

Biomarkers, Tumor↗
PubMed1992

Presence of elevated levels of platelet-derived growth factor (PDGF) in lung adenocarcinoma pleural effusions.

Significant tumor stroma development is a specific feature of adenocarcinoma of the lung in comparison to small-cell lung cancer (SCLC). The fibrotic component of tumor stroma is thought to result from the migration and local replication of mesenchymal cells in response to the presence of cytokines. One of them, platelet-derived growth factor (PDGF), is a chemotactic and growth factor for mesenchymal cells. Since several lung adenocarcinoma cell lines, but not SCLC cell lines, have been shown in vitro to express PDGF genes, we evaluated pleural effusions for the presence of PDGF in patients with adenocarcinoma of the lung, SCLC, or nonmalignant pleural effusions. In adenocarcinoma of the lung, PDGF levels in pleural effusions were higher than in SCLC and in nonmalignant pleural effusions and were associated with the presence of a growth-promoting activity for fibroblasts due, in part, to the presence of PDGF. This observation suggests the role of PDGF in tumor stroma formation in adenocarcinoma of the lung.

Adenocarcinoma↗
PubMed1992

[Significance of the level of carcinoembryonic antigen in the alveolar lavage fluid in cancerous and non-cancerous bronchopulmonary pathology].

In a prospective study the level of carcinoembryonic antigen (ACE) were simultaneously measured in plasma and bronchoalveolar lavage liquid (LBA), in fifteen patients suffering from bronchopulmonary cancer and fifteen patients suffering from non-malignant pulmonary disease. In these two groups the level of ACE in LBA liquid (cancer 8,990 +/- 4,050 ng/ml; controls 2,510 +/- 1,060 ng/ml) were clearly more elevated than the corresponding plasma levels (cancer 1,931 +/- 1,760 ng/ml; controls 8.2 +/- 2 ng/ml) and the plasma levels of ACE were more elevated in the cancer group; in the same group the ACE levels in the LBA liquid were more elevated in the tumour group (4,770 +/- 2,180 ng/ml versus 808 +/- 300 ng/ml). This study has also shown the elevated levels of ACE in the LBA liquid in patients suffering from chronic bronchial inflammation (2,510 +/- 1,060 ng/ml) and during the course of acute bacterial pneumonia. The contribution of the ACE level in LBA liquid in relation to the plasma levels in the diagnosis of bronchopulmonary cancer would thus appear to have no clinical value, but the exact relationships between the phenomenon of chronic bronchial inflammation and metaplasia of the bronchial epithelium merit further study.

Biomarkers, Tumor↗
PubMed1990

[Diagnostic pitfalls, artefacts and difficulties of thoracic radiography].

The antero-posterior X-ray film of the chest is still a basic examination in everyday clinical practice. It supplies multiple data but reading of the image is difficult and requires much accuracy and method. In this review paper we examine all the artefacts, pitfalls and diagnostic problems we have encountered in many years of experience, irrespective of their cause (technical, iatrogenic) or origin (parietal, intrathoracic, pleural, vascular, gastrointestinal, mediastinal, pulmonary). We consider that all pneumologists should have in mind these problems when faced with doubtful or abnormal radiographs of the chest.

Aorta, Thoracic↗
PubMed1990

[Muscular metastasis of primary bronchial carcinoma].

We report 2 cases of muscle metastases from primary lung cancer (an adenocarcinoma and one epidermoid carcinoma). In one patient the metastases revealed the disease. This site of metastasis seems to be exceptional since only 46 cases have been published, but its frequency is probably underestimated. A retrospective study of the last 10 years and an exhaustive review of the literature have enabled us to determine the frequency of muscle metastases from lung cancer and their physiopathological implications.

Adenocarcinoma↗
PubMed1990

[The incidence of atypical pulmonary mycobacterium infections in Reunion before the era of acquired immunodeficiency syndrome (AIDS)].

The authors analyzed cases of pulmonary non-tuberculous mycobacterial infection observed in the Reunion Island between 1979 and 1986, before any reported case of AIDS in the Island. Isolation of non tuberculous mycobacteria from bronchopulmonary specimens was estimated at 21.4% among all positive cultures (n = 971). The analysis of clinical and biological data from 791 different patients with a positive culture concluded to the responsibility of a non tuberculous mycobacteria in 117 (14.8%); among these 117, only 10 (8.5%) were considered as pathogen. Species repartition, antituberculous drug sensitivity and clinical out come are discussed.

Adult↗
PubMedDate not supplied

[High dose endobronchial brachytherapy: a curative treatment].

PURPOSE: New endobronchial techniques of treatment allow a good unblocking. Nevertheless, only high dose rate brachytherapy delivers a curative treatment for invasive carcinomas. This study analyses the results of the first 33 consecutive patients treated with curative intent by this technique from 1994 to 1997, and followed-up more than one year. PATIENTS AND METHODS: Thirty-seven lesions were treated, with usual schedule delivering 30 Gy at 1 cm depth in six fractions and three to five weeks. All the patients were meticulously selected on the local involvement of the tumour and absolute contraindications to a surgical treatment. All of them have a pulmonary disease history or a general contraindication. RESULTS: With a 14-month follow-up, the local control at two months after the treatment was 95% (endoscopic and histologic), and 90% of the patients presented a prolonged local control. Four patients died of the treated cancer, another of a controlateral cancer. Ten patients died of another disease, five of them from a respiratory insufficiency. The overall survival rate at two years was 53% and the specific survival rate 80%. The acute tolerance was good, without incident. Asymptomatic bronchial stenoses, described by endoscopic follow-up, were described for seven patients. CONCLUSION: We conclude that, on the basis of a good selection of the patients and a respect of the indications, high dose rate endobronchial brachytherapy is an effective curative treatment. It offers a new curative option and must be proposed for the small invasive carcinomas in non-operable patients.

Brachytherapy↗