Search PubMed⌕ Search

Biomedical subjects

F Lecomte

Publications and source records attributed to F Lecomte.

At least 19 recordsLinked to original sources
PubMed2000

[A numerical simulation of the aerodynamics of the nasal cavity].

We present the results of the numerical simulation of the flow in the nasal cavity, going from the tip of the nostril to the nasopharyngeal region. The volume of the nasal cavity, obtained from axial and coronal scans, takes into account the geometries of the nasal valve and turbinates. The simulation is carried out with the FLUENT code which solves the equations of fluid mechanics. The obtained results for the inspiratory phase are analyzed from the velocities and pressures, paying special attention to the separation of the streamlines in the region located between the middle meatus and the olfactory area. The presented results show the potential of simulation when used in parallel with the clinical approach.

Computer Simulation↗
PubMed1999

Diffusion-controlled drug delivery systems: calculation of the required composition to achieve desired release profiles.

The aim of this study was to investigate the effect of the composition of diffusion-controlled release devices (type and amount of plasticizer, type of polymer) on the drug diffusivity and the resulting release kinetics in a quantitative way. Diltiazem hydrochloride and theophylline were investigated in ethyl cellulose (EC) and Eudragit((R)) RS 100, plasticized with various amounts of acetyltributyl citrate (ATBC), acetyltriethyl citrate (ATEC), dibutyl phthalate (DBP), dibutyl sebacate (DBS), diethyl phthalate (DEP), and tributyl citrate (TBC). Thin drug-containing films (monolithic solutions) were used to determine the diffusion coefficients experimentally. The effect of the type and amount of plasticizer on the drug diffusivity was found to be significant, whereas the chain length of the polymer only played a minor rule in the investigated systems. Interestingly, a quantitative relationship between the diffusion coefficient of the drug and the plasticizer level could be established. Based on these results, the release kinetics of diffusion-controlled drug delivery systems could be predicted. In this study, the release patterns from microparticles were calculated and the significant effect of the composition of the device on the resulting release rate was simulated. The latter could be effectively modified by varying the type and amount of plasticizer. Independent experiments verified the theoretical predictions. The practical benefit of the presented method is to calculate the required composition of diffusion-controlled drug delivery systems (monolithic solutions) to achieve desired release profiles.

Cellulose↗
PubMed1999

Hypertrophic osteoarthropathy can indicate recurrence of Whipple's disease.

We report the case of a patient with Whipple's disease (WD) who developed hypertrophic osteoarthropathy (HOA) characterized by digital clubbing, periostosis of the tubular bones, and polysynovitis. The HOA disclosed the recurrence of the patient's WD, since polymerase chain reaction (PCR) analysis clearly demonstrated the presence of Tropheryma whippelii in the synovial fluid from the patient's left knee. Initiation of appropriate antibiotic therapy resulted in complete healing of all clinical rheumatologic manifestations within 2 months and in disappearance of radiographic bone changes at 7-month followup. We suggest that HOA be included within the spectrum of rheumatologic manifestations of WD, and that an evaluation for WD should be considered in patients, especially middle-aged men, presenting with HOA even without gastrointestinal symptoms. PCR analysis may be useful in accurate diagnosis and management of early WD with unusual clinical manifestations, and may contribute to decreased morbidity and mortality.

Anti-Bacterial Agents↗
PubMed1999

[Are antiphospholipid antibodies thrombogenic in the course of human immunodeficiency virus infection?].

Lupus-like anticoagulant is commonly encountered in human immunodeficiency virus infection although thromboembolic manifestations are rare in HIV patients. We report the case of an HIV patient who developed gangrene of both forefeet associated with anticardiolipin antibodies. A 42-year-old woman had a 12-year history of HIV infection (stage B2). She presented with painful gangrene involving the forefeet of 4-day duration. Doppler ultrasonography, electromyography and nailfold capillaroscopy were normal. Skin biopsy revealed intracapillary thrombi and severe necrosis within the hypodermis; there was no evidence of vasculitis. Laboratory findings showed a marked inflammatory syndrome and the presence of anticardiolipin antibodies (IgG: 22 GPL U/ml). Several cutaneous manifestations are known to be associated with antiphospholipid syndrome, such as livedo reticularis, ulcers and gangrene of the extremities. Skin biopsy often shows noninflammatory thrombosis of small vessels within the dermis. Microcirculation damages have also been described in HIV infection, mainly vasculitis. In the present case report, the absence of both vasculitis and other causes suggest that anticardiolipin could be the culprit. But, it is possible that painful gangrene of the forefeet was secondary to HIV infection.

Adult↗
PubMed1998

[New macrolides].

INTRODUCTION: Following their use for a few years, the place of new macrolides can be assessed. CURRENT KNOWLEDGE AND KEY POINTS: "New macrolides", ie, roxithromycin, clarithromycin, azithromycin and dirithromycin, are derivated from erythromycin and defined by different pharmacokinetic parameters: longer half time with better oral administration and shorter duration of treatment, better tissue concentrations with reduction of dosages and better tolerance, high cellular concentration with good activity. However, new macrolides and erythromycin do not show major differences in their antibacterial spectrum against usual pyogenic strains. Clinical use of new macrolides extends to opportunistic infections, such as atypical mycobacterial infections or toxoplasmosis, occurring in the course of HIV infection. New macrolides are also recommended for the treatment of Helicobacter pylori-related gastroduodenal ulcer. FUTURE PROSPECTS AND PROJECTS: New macrolides have opened new avenues in the development of anti-infectious strategies. Due to their good efficacy against Chlamydia pneumoniae which is suspected of inducing vascular diseases, the upcoming use of ketolids and the development of their non-antibiotic effects, the future of macrolides is favorable.

AIDS-Related Opportunistic Infections↗
PubMed1997

The S3a ribosomal protein gene is identical to the Fte-1 (v-fos transformation effector) gene and the TNF-alpha-induced TU-11 gene, and its transcript level is altered in transformed and tumor cells.

Previous work on mouse x rat hybrid cells (BS series) led to the assignment of a transformation suppressor locus (Sail) to the rat 5q22-q33 region. This gene is not yet identified. From a non-transformed BS hybrid cell line, we isolated a partial cDNA insert (13T), which detects a transcript more abundant in transformed cells than in their non-transformed homologs. Sequence comparisons led us to conclude that 13T is identical to the coding sequences of the ribosomal protein S3a gene (Rps3a), of Fte-1 (v-fos transformation effector gene) and of TU-11, a mouse gene induced by TNF-alpha. Rps3a, Fte-1 and TU-11 are thus one and the same gene. Similarity was also found between this gene and non-mammalian sequences reported to be involved in cell cycling. Like the Rps3a transcript level, the c-Fos transcript level is higher in transformed cells. Rps3a and Fos could thus be effectors of the transformed phenotype.

Animals↗
PubMed1997

[Red fingers syndrome in the course of HIV infection. A new case].

Human immunodeficiency virus can be associated with vascular manifestations such as arteritis mainly with cerebrovascular localization, arterial aneurysms or accelerated formation of atherosclerosis lesions. Red fingers syndrome has been recently described in i.v.-drug patients with HIV and hepatitis C infection. We report a new case in a 36-year old woman, and suggest that this syndrome must be considered as a new microcirculatory manifestation of HIV infection. Red fingers syndrome in patients with HIV is likely secondary to co-infection with hepatitis C or immunological disturbances-associated such as cryoglobulinemia.

AIDS-Related Opportunistic Infections↗