Biomedical subjects

François-Xavier Blanc

Publications and source records attributed to François-Xavier Blanc.

6 recordsLinked to original sources

PubMed2005

The effects of isoflurane on airway smooth muscle crossbridge kinetics in Fisher and Lewis rats.

Our aim was to determine how isoflurane modified crossbridge (CB) number and kinetics in airway smooth muscle (ASM) and to compare its effects in Fisher and Lewis rats, two strains with differences in airway responsiveness. The effects of isoflurane (2 MAC) on isotonic and isometric contractility in tracheal ASM strips were investigated after methacholine (10(-6) M)-induced contraction. CB mechanics and kinetics were analyzed using the formalism of Huxley's equations adapted to ASM. After isoflurane, maximum velocity did not differ from baseline in Lewis rats, whereas it was significantly less than baseline in Fisher rats ( approximately 25%), the most reactive strain. Isoflurane totally reversed methacholine-induced increase in active CB number in Lewis rats (2.4 +/- 0.5 versus 1.8 +/- 0.4 10(9)/mm(2) after methacholine and isoflurane, respectively) whereas reversal was only partial in Fisher rats (2.7 +/- 0.4 versus 2.1 +/- 0.3 10(9)/mm(2) after methacholine and isoflurane, respectively). Isoflurane induced a 40% increase in attachment step duration in both strains and an almost twofold increase in the CB cycle duration compared with baseline in Lewis rats. The isoflurane-induced increase in detachment step duration was less in Lewis than in Fisher rats (P < 0.05). We concluded that isoflurane modulated CB number and CB cycling rates of isolated rat ASM differently depending on the level of airway responsiveness.

Algorithms↗

PubMed2005

Efficacy of rituximab in refractory polymyositis.

We describe the effectiveness of rituximab, an anti-B lymphocyte monoclonal antibody, in a case of refractory polymyositis with interstitial pulmonary disease and anti-Jo-1 autoantibody (antisynthetase syndrome). Rituximab was well tolerated, and its efficacy in inflammatory myositis should be evaluated.

Antibodies, Antinuclear↗

PubMed2004

Sarcoidosis in HIV-infected patients in the era of highly active antiretroviral therapy.

To analyze the impact of highly active antiretroviral therapy (HAART) on the characteristics and outcome of sarcoidosis in patients infected with human immunodeficiency virus (HIV), we identified HIV-infected patients in whom sarcoidosis was diagnosed between 1996 and 2000 from the admission registers of the pneumology departments of 12 hospitals in the Paris region (France). Sarcoidosis was diagnosed in 11 HIV-infected patients, of whom 8 were receiving HAART. HIV infection was diagnosed before sarcoidosis in 9 cases. At diagnosis of sarcoidosis, the mean CD4 cell count (+/-SD) was 390+/-213 cells/mm(3), and the mean plasma virus load was 4002+/-10,183 copies/mL. Sarcoidosis occurred several months after HAART introduction, when the CD4 cell count had increased and the plasma HIV load had decreased. Clinical and radiological characteristics, laboratory values for bronchoalveolar lavage fluid samples, and outcome after a long follow-up were similar for the patients receiving HAART and for HIV-uninfected patients.

Anti-HIV Agents↗

PubMed2004

Mechanical properties of tracheal smooth muscle are impaired in the rabbit with experimental cardiac pressure overload.

UNLABELLED: STUDY OBJECTIVES/DESIGN: Impaired function of striated and arterial smooth muscle is known to occur in humans and animals with various forms of cardiac diseases, but limited information is available on the mechanical behavior of airway smooth muscle. We tested the hypothesis that the baseline mechanical properties of tracheal smooth muscle (TSM) were impaired at an early stage of cardiac overload. ANIMALS: We used a model of cardiac hypertrophy induced by surgical abdominal aortic stenosis (AS) in adult rabbits. Twelve animals with AS and 8 sham-operated control rabbits were studied 12 weeks after surgery. In rabbits with AS, the heart weight/body weight ratio was higher than in control rabbits (2.36 +/- 0.43 g/kg vs 1.98 +/- 0.20 g/kg, p < 0.05) [mean +/- SD], attesting to moderate cardiac hypertrophy. No clinical signs of congestive heart failure were observed. MEASUREMENTS: Isolated TSM strips were electrically stimulated at 37 degrees C, 2.5 mM [Ca(2+)](0), against 8 to 10 load levels, from zero load to full isometry. Force-velocity relationship was elicited using the conventional afterloaded isotonic method. RESULTS: Peak isometric tension was lower in rabbits with AS than in control rabbits (25 +/- 11 mN/mm(2) vs 34 +/- 14 mN/mm(2), p < 0.05), whereas maximum unloaded shortening velocity, maximum extent of muscle shortening, and relaxation parameters did not differ between groups. The curvature of the force-velocity relationship (which reflects the myothermal economy of force generation) and peak mechanical efficiency were lower in rabbits with AS than in control rabbits. CONCLUSIONS: These results indicate that the contraction of isolated rabbit TSM was less powerful and less economical in cardiac hypertrophy, attesting to early impairment of the mechanical properties of TSM during cardiac overload.

Animals↗

PubMed2003

[Severe acute asthma].

A severe acute asthma attack is defined by the presence of clinical signs of severity and/or a value of peak expiratory flow (PEF) < 30% predicted. The treatment is based mainly on inhaled beta 2 agonists and systemic corticosteroids. Nebulization is the route of administration of choice, because of its simplicity, its efficacy and its tolerability. Anticholinergics are indicated in association with nebulised beta 2 agonists. Response to treatment must be evaluated within an hour, permitting the early detection of "responders" or "non-responders" to the initial treatment. The great majority of deaths from acute asthma are avoidable, underlining the importance of preventive measures. Prevention is based on the control of the asthma by personalized ongoing treatment based on long-term inhaled corticosteroids and the use of oral corticosteroids in the treatment of exacerbations. However, a severe acute asthma attack can appear at any stage of severity of asthma, including controlled asthma, justifying the utilisation of action plans to treat exacerbations.

Acute Disease↗

PubMed2002

Diagnostic value of medical thoracoscopy in pleural disease: a 6-year retrospective study.

STUDY OBJECTIVES: Unlike thoracocentesis and closed pleural biopsy (CPB), medical thoracoscopy permits biopsy with direct visualization. In a 6-year retrospective study of patients having undergone at least one medical thoracoscopy, we analyzed the diagnostic yield of thoracoscopy and its value in the management of pleural disease. SETTING/PATIENTS: From January 1, 1989, to December 31, 1994, 168 medical thoracoscopies were performed on 154 patients (123 men; mean age +/- SE, 61 +/- 1 years), of which 149 were diagnostic and 19 were indicated for therapeutic assessment in malignant mesothelioma (MM). Prior to thoracoscopy, at least one CPB had been performed in 120 of 149 cases, yielding a diagnosis in 96 cases. RESULTS: Thoracoscopy challenged the CPB-based diagnosis in 43 of 96 cases. In 66 cases of nonspecific inflammation diagnosed by CPB, thoracoscopy revealed MM in 16 cases, adenocarcinoma in 10 cases, undetermined carcinoma in 3 cases, and pleural tuberculosis in 3 cases. In 18 cases in which the CPB diagnosis was MM, thoracoscopy, performed for precise staging, challenged the diagnosis in 4 cases. In 12 cases of carcinoma diagnosed by CPB, thoracoscopy specified the histologic type in 7 cases. Thoracoscopic diagnoses were found to be erroneous in 10 of 149 cases, mainly owing to pleural adhesions that limited access to the pleural cavity. There was one thoracoscopy-related death, one case of sepsis, and six cases of empyema. CONCLUSIONS: Medical thoracoscopy appears to be efficient and relatively safe in the management of pleural disease. Pleural adhesions can lower its diagnostic value.

Adenocarcinoma↗