Biomedical subjects

S Pontier

Publications and source records attributed to S Pontier.

8 recordsLinked to original sources

PubMed2006

[Exacerbations of COPD: An audit of emergency department practice in France].

INTRODUCTION: Exacerbations of COPD are potentially serious events, the recognition and treatment of which appear to be poorly understood by both patients and doctors. The aim of this study is to describe, on the basis of two case histories, the management of exacerbations of COPD in emergency departments, to compare it with the current guidelines and to evaluate the extent of use of non-invasive ventilation in decompensated COPD. METHODS: The study took place between February and June 2004. Two case histories describing one moderate and one severe exacerbation with respiratory failure were written by the authors of the study and submitted to an emergency physician in a university hospital and a district hospital in each region. RESULTS: 110 questionnaires were returned from 20 university hospitals and 25 district hospitals. Only 38% of the episodes were identified correctly. 20% of doctors did not regard dyspnoea as a clinical sign of an exacerbation. 22% of doctors never prescribed bronchodilators, even in severe cases. Finally, non-invasive ventilation (NIPV) was used for only 9% of the moderate and 56% of the severe exacerbations. DISCUSSION: This study, although limited by certain factors, illustrates a number of points in need of improvement in the recognition and treatment of exacerbations of COPD in emergency departments, the use of NIPV, and the collaboration between emergency physicians, intensivists and respiratory physicians.

Emergency Service, Hospital↗

PubMed2004

[Granulomatous pneumocystis pneumonia].

INTRODUCTION: Granulomatous pneumocystis pneumonia (PCP) is a rarity whose presentation may be misleading. CASE REPORT: We report the case of a patient suffering from chronic lymphatic leukaemia presenting with acute respiratory insufficiency, with a fatal outcome, due to granulomatous PCP. Broncho-alveolar lavage (BAL) remained negative and the diagnosis could only be made later by open lung biopsy. CONCLUSION: Although infrequent, granulomatous PCP should be recognised because in this situation the standard investigation (BAL) may be negative. New, more sensitive, methods of investigation such as the polymerase chain reaction (PCR) may permit earlier diagnosis.

Biopsy↗

PubMed2003

[Intra-vascular lymphoma presenting with respiratory symptoms].

INTRODUCTION: Intra-vascular large cell lymphoma is a rare disease characterised by the proliferation of malignant cells within small blood vessels. CASE REPORT: We report a case of intra-vascular lymphoma presenting with unexplained dyspnoea, hypoxaemia and associated neurological symptom. The diagnosis was made by liver biopsy but the patient ultimately died. CONCLUSIONS: Earlier diagnosis with transbronchial biopsy might have improved the prognosis by allowing more prompt treatment.

Aged↗

PubMed2001

Estradiol decreases the acetylcholine-elicited airway reactivity in ovariectomized rats through an increase in epithelial acetylcholinesterase activity.

Estrogen replacement therapy (ERT) is frequently prescribed for postmenopausal women. Epidemiological data suggest that sex hormones may play a role in the expression of asthma, but the mechanism(s) whereby this influence is mediated remain(s) unclear. To better understand the role of physiologic doses of estrogens in airway function, we tested the hypothesis that 17beta-estradiol (E(2), 10 microg/kg per d for 21 d) given to oophorectomized female rats modifies airway responsiveness to cholinergic agonists, compared with oophorectomized rats given placebo. In vivo, the concentration of inhaled acetylcholine (ACh) required to double pulmonary resistance (EC(200)RL) in anesthetized spontaneously breathing tracheotomized rats was calculated as an index of airway responsiveness. E(2)-treated rats were less responsive to ACh than placebo-treated rats (EC(200)RL, 9.40 +/- 1.48 vs. 1.52 +/- 0.85 mg. ml(-1), respectively). Ex vivo airway responsiveness was evaluated with the cumulative concentration-response curve (CCRC) of isolated tracheal segments. Compared with placebo, E(2) treatment significantly increased the EC(50) of ACh (p = 0.01) but did not alter the CCRC to carbachol. Removing the epithelium or treatment with physostigmine abolished the difference in EC(50) of ACh between the groups. Acetylcholinesterase (AChE) activity of homogenized whole trachea was 1.4-fold greater in the E(2)-treated group compared with placebo (p = 0.02), whereas no difference was found in homogenized epithelium-free trachea. We conclude that E(2) treatment decreases airway responsiveness to ACh in ovariectomized rats at least in part by increasing AChE activity dependent on the presence of the epithelium.

Acetylcholine↗

PubMed2001

Allosteric effects of G protein overexpression on the binding of beta-adrenergic ligands with distinct inverse efficacies.

Allosteric models of G protein-coupled receptors predict that G protein influences the spontaneous isomerization between inactive (R) and active (R*) conformations. Since inverse agonists have been proposed to preferentially bind to the inactive and uncoupled form(s), changes in the G protein content should influence the binding properties of these ligands. To test this hypothesis, we systematically assessed the effect of G proteins on the binding of beta(2)-adrenergic ligands with distinct levels of inverse efficacy. Recombinant baculoviruses encoding the human beta(2)-adrenoreceptor (beta(2)AR) were expressed alone or in combination with G protein subunits in Sf9 cells. Coexpression with the G protein alpha s beta 1 gamma 2 did not influence the relative efficacy of the ligands to inhibit the adenylyl cyclase but induced considerable decrease in number of sites detected by [(3)H]ICI 118551, [(3)H]propranolol, and (125)I-cyanopindolol. This loss was proportional to the inverse efficacy of the ligand used as the radiotracer in the assay. The addition of Gpp(NH)p inhibited the effects of G protein overexpression indicating that the G proteins acted allosterically. Consistent with this notion, Western blot analysis revealed that coexpression with the G proteins was not accompanied by a loss of immunoreactive beta(2)AR. Such allosteric effects of the G proteins were also observed in mammalian cells expressing endogenous level of G proteins indicating that the phenomenon is not unique to overexpression systems. Taken together, these results demonstrate that the apparent receptor number detected by radiolabeled inverse agonists is affected by the content in G proteins as a result of their influence on R/R* isomerization.

Allosteric Regulation↗

PubMed2001

[Acquired right-to-left shunt with normal right heart pressure].

Intracardiac right-to-left shunting through a patent ovale foramen (POF) despite normal right-sided pressures is an uncommon cause of dyspnea with posture worsening in adults. We report herein 6 cases which sum up etiological circumstances, diagnostic workup and management of this syndrome. The main reported etiopathologic mechanism is consistent with a change in the internal configuration of the right atria leading to preferential blood flow from inferior vena cava through patent foramen ovale. The treatment lies on surgical closure of the septal defect, which can now be performed using a noninvasive percutaneous procedure.

Aged↗

PubMed2000

[Chronic necrotizing pulmonary aspergillosis and ankylosing spondylarthritis].

Fibro-bullous disease is a late complication of ankylosing spondylarthritis. Its radiologic features frequently mimics tuberculosis or excavated neoplasm. About 50 to 65% of patients with ankylosing spondylarthritis have chronic aspergillus colonization of their airways. Pulmonary aspergillosis infection occurs in 10 to 30% during evolution. We report two cases of patients with spondylarthritis who developed chronic necrotizing pulmonary aspergillosis. Diagnosis was based on serology, mycologic examination of expectoration and in one case on histology obtain by transbronchial biopsies. Pulmonary complications due to aspergillus species frequently reveal an associated fibro-bullous disease in patients with ankylosing spondylarthritis. This can be reported to diminished chest wall movements in such patients. Treatment is based on administration of anti-fungal drugs. In case of medical treatment failure, thoracic surgery may be indicated.

Adult↗

PubMed1985

Human monocyte-endothelial cell interaction in vitro.

We have examined the interaction of freshly isolated human blood monocytes with cultured human umbilical vein endothelial cells in vitro. Purified monocytes incubated with confluent primary or passaged endothelial cells (EC) for 90 min at 37 degrees C bound at maximal densities of 6.5-7.0 X 10(3)/mm2 (8 or 9 per EC) without causing disruption of the monolayer. Monocyte-EC binding proceeded in the presence of plasma proteins or optimal phagocytic doses of opsonized zymosan particles. The avidity of attachment was not diminished by alternative monocyte isolation techniques. Monocyte attachment to EC was dependent upon the presence of divalent cations (magnesium greater than calcium) and was inhibited at 4 degrees C. Monocytes selectively bound to EC when incubated with monolayers composed of smooth muscle cells and EC. Neither EC monolayer confluence nor a variety of EC culture conditions affected the high levels of monocyte binding. In contrast, human neutrophils (less than 1 per EC) and lymphocytes (less than 2-3.5 per EC) bound at lower maximal densities under the same conditions, while platelet reactivity remained minimal. The distinctively higher affinity of human blood monocytes relative to other circulating white cells for binding to cultured human EC may have relevance to their function in vivo.

Cell Adhesion↗