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Biomedical subjects

L Renard

Publications and source records attributed to L Renard.

At least 19 recordsLinked to original sources
PubMed2005

Implementation of isolation precautions: role of a targeted information flyer.

Isolation precautions are advocated in most countries for patients harbouring multi-drug-resistant organisms. We evaluated the impact of a targeted information flyer on the implementation of isolation precautions for patients with methicillin-resistant Staphylococcus aureus (MRSA). A flyer providing a quick reference to the steps to be implemented following detection of MRSA was sent systematically by the microbiologists with all results displaying MRSA. Infection control staff compared isolation precautions in two three-month periods: the first (control) period before implementation of the flyer and the second (intervention) period after implementation of the flyer. Compared with the control period, compliance with isolation precautions increased significantly in the intervention period. In intensive care units, there was a sign posted on the door for 31 of 38 (82%) patients in the control period, and 33 out of 34 (97%) in the intervention period (P=0.06). Use of gowns increased from 82% to 100% (P=0.01), use of dedicated materials increased from 84% to 100% (P=0.03), availability of alcohol hand rub increased from 82% to 94% (P=0.10), and the proportion of MRSA patients in private rooms increased from 71% to 91% of the cases (P=0.07). In conclusion, compliance with isolation precautions increased after attaching a flyer to all MRSA-positive bacteriological results.

Humans↗
PubMed2002

Concurrent spinal cord and vertebral bone marrow radionecrosis 8 years after therapeutic irradiation.

Concurrent radionecrosis within the spinal cord and the bone marrow at the same thoracic level was observed 8 years after localized therapeutic irradiation in a patient who had undergone repeated cycles of radiotherapy, glucocorticoid treatment, and chemotherapy for a non-Hodgkin's lymphoma. Mechanisms combining radiotoxic potentialization by glucocorticoids/alkylating agents and delayed radiation-induced vasculitis involving the common arterial pathways to the spinal cord and to the vertebrae were speculated to have acted in a synergistic way.

Adult↗
PubMed2001

Comparison of setup accuracy of three different thermoplastic masks for the treatment of brain and head and neck tumors.

PURPOSE: Setup accuracy is an important factor influencing the definition of the planning target volume (PTV). The purpose of this study was to compare the setup accuracy of three different thermoplastic masks used for immobilization of patients with brain or head and neck tumors. MATERIALS AND METHODS: Thirty patients with brain or head and neck tumors were consecutively assigned to one of three different thermoplastic masks (Posifix): head mask with three fixation points (3 FP, ten patients), head and shoulder mask with four fixation points (4 FP, ten patients), head and shoulder mask with five fixation points (5 FP, four fixations plus an additional one on the top of head, ten patients). Once a week, during the session with a 6 MV linac (Elekta), orthogonal (antero-posterior and lateral) portal images were acquired for three fictitious isocenters placed during the simulation at the level of the head, the neck and the shoulders. Portal images and digitized simulator films were compared using the PIPS pro software, and displacements in antero-posterior (A-P), cranio-caudal (C-C) and medio-lateral (M-L) directions were calculated. From these displacements, 2D or 3D errors were also calculated. RESULTS: A total of 915 portal images were obtained, of which 98% could be analyzed. For the whole population, total displacements reached a standard deviation (SD) of 2.2 mm at the level of the head and the neck. Systematic and random displacements were in the same order of magnitude and reached a SD of 1.8 mm. Patient setup was slightly worse at the shoulder level with a total displacement of 2.8 mm (1 SD) for both the C-C and the M-L directions. There again, the systematic and the random components were in the same order of magnitude below 2.4 mm (+/-SD). For isocenters in the head and in the neck, there was no substantial difference in the setup deviation between the three masks. The setup reproducibility was found to be significantly worse (P=0.01) at the level of the shoulders with the 3 FP mask. For the 2D random error, 1 SD of 2.3 mm was observed compared to 0.8 and 1.2 mm for the 4 and 5 FP masks, respectively. Lastly, 90% of the 3D total deviations were below 4.5 mm for the head and the neck. In the shoulder region, 90% of the 2D total deviations were below 5.5 mm. CONCLUSION: Thermoplastic masks provide an accurate patient immobilization. At the shoulder level, setup variations are reduced when 4 or 5 FP masks are used. These data could be used for the assessment of margins for the PTV.

Algorithms↗
PubMed2000

Optic nerve sheath meningiomas: clinical features, functional prognosis and controversial treatment.

Optic nerve sheath meningiomas (ONSM) are rare benign neoplastic lesions arising from meningothelial cells of the meninges. As clinical features are highly variable, the diagnosis is often delayed. From 1995 to 1999, 6 patients were diagnosed with ONSM in our department. We compared our series with the literature data. Visual prognosis is usually poor. Despite a large literature, the treatment guidelines are still highly controversial.

Adult↗
PubMed1997

[Possibilities of psychoanalytic treatment in child and adolescent psychiatry in France].

This article describes the context of psychoanalytical approaches and their influence upon child and adolescent psychiatry in an historical and organisational perspective. It deals with some current advances and discussions with regard to technical aspects: indication, frame and process as well as extensions of technique, that will raise weaknesses in questions about training in psychotherapy.

Adolescent↗
PubMed1996

Pharmacokinetic-pharmacodynamic model for spiramycin in staphylococcal mastitis.

Simultaneous pharmacokinetic-pharmacodynamic (PK/PD) modelling for spiramycin in staphylococcal infections of the mammary gland of cows was used to predict the efficacy of spiramycin. A differential equation derived from the Zhi model was fitted to an in vitro killing curve and post-antibiotic effect determination. A seven-compartment PK model, in which 4 compartments representing each quarter of the mammary gland which was considered to be the effect compartment, was included. The PD model linked to the PK model was able to describe the in vivo spiramycin effect against Staphylococcus aureus. The parameters calculated from in vitro data predicted a rapid decrease for the first 12-24 h, and regrowth within 72 h following the treatment, whereas in vivo the bacterial effect was much less after 24 h than that predicted by the in vitro data. PK/PD modelling permitted the simulation of various doses to optimize the efficacy of the antibiotic, taking into account such dynamic parameters as bacterial growth rate constant, bacterial killing rate constant and the Michaelis-Menten type saturation constant. An optimal dosage regimen of 20000 IU/kg per day for 3 days was predicted for the treatment of Staphylococcus aureus mastitis.

Absorption↗
PubMed1996

[Bactericidal effect of colistin on Escherichia coli. Model and simulation or the pharmacokinetic-pharmacodynamic relation for prediction of efficacy in veterinary antibiotic therapy].

Pharmacodynamics studies consider three main parameters: the size of the bacterial population, the concentration of the antibiotic and the duration of its action. The pharmacodynamic characteristics of colistin were studied in vitro with Escherichia coli. The bacterial kinetics were fitted using differential equations. The mathematical model gave qualitative and quantitative information about the characteristics of the antibiotic-bacteria association. Above all, when linked to a pharmacokinetic model, the model permitted the prediction of the drug's efficiency. Simulations of various dosage levels in which the administration route, dose size, or interval between doses varied, permitted a more rational optimization than a prediction of efficacy based on the time taken to achieve antibiotic plasmatic concentrations above the minimal inhibitory concentration. Pharmacokinetic/pharmacodynamic modeling seems to be an interesting possibility for determining antibiotic dosing levels during the preclinical phase.

Animals↗
PubMed1996

[Radiotherapy treatment of subfoveal retinal neovascularization related to age].

Thirty-three patients who underwent low dose of radiation therapy for subfoveal choroidal membranes were studied after a mean follow-up of 16 months. The evaluated parameters were the visual outcome and the choroidal neovascularization evolution. In this study, the efficacy of low-dose radiation delivered to the macular region as an alternative treatment in subfoveal membrane was limited.

Age Factors↗
PubMed1994

Determination of spiramycin and neospiramycin in plasma and milk of lactating cows by reversed-phase high-performance liquid chromatography.

After chloroform extraction, the rapid and sensitive determination of spiramycin and neospiramycin can be performed with AASP-diol clean-up cartridges prior to reversed-phase C18 high-performance liquid chromatography. The limits of quantification of spiramycin in plasma and milk are 0.023 and 0.013 microgram/ml, respectively, and those of neospiramycin, are 0.058 and 0.006 microgram/ml, respectively. Application of the method to the analysis of plasma and milk samples obtained from pharmacokinetic studies is described. Spiramycin has a terminal half-life of 14.27 h in plasma and 34.59 h in milk, while neospiramycin has a half-life of 25.62 h in plasma and 105.85 h in milk.

Animals↗
PubMed1993

[Modeling of the bactericidal effect of spiramycin. Choice of a pharmacodynamic model].

The modelling of in vitro growth curves of Staphylococcus aureus ATCC 6538P at different pHs, of spiramycin killing curves and of the dose-effect relationship was performed. The growth curve was characterised by a Volterra-Kostitzin differential model, the main parameters of which were the bacterial growth rate constant of 0.95 +/- 0.13 h-1 and a lag-time of 0.74 +/- 0.36 h. The Zhi model used for bactericidal kinetics showed the same bacterial killing rate constant from a minimum concentration characteristic of "time-dependent" antibiotics. This differential model incorporated with pharmacokinetic models could lead to a rationale for proper dosage regimens.

Culture Media↗
PubMed1991

[Pharmacokinetics of colistin sulfate administered by intravenous and intramuscular routes in the calf].

Pharmacokinetic characteristics of an extemporaneous form of colistin sulfate in young calves were studied for a dosage of 25,000 IU.kg-1. The intravenous route (IV) is characterized by a 3-compartment model whose main parameters are: volume of distribution (1.02 l.kg), body clearance (0.15 l.h-1 kg-1) and mean residence time (3.87 h). By intramuscular route (IM), a mean serum peak of 37 IU.ml-1 was reached at a mean time of 0.5 h. The mean half-time of terminal phase (6.47 h) does not differ significantly from that of the intramuscular route (4.52 h). Absolute bioavailability calculated based on 4 calves was 109 +/- 28%. Repeated IM administrations seem to be adapted to maintain a bactericidal activity and to reduce risks of toxicity and neurological disorders (25,000 IU.kg-1) every 12 h over 3d.

Animals↗
PubMed1989

Neutron therapy of soft tissue sarcoma at Louvain-la-Neuve (interim results 1987).

The results of fast neutron therapy of soft tissue sarcoma at the cyclotron of Louvain-la-Neuve are reviewed. 75 patients were analysed, the follow-up ranged from six to 102 months (mean: 30.7 months). 47 patients were treated after radical surgery. A local control rate of 91.5% (43/47) was achieved, and 70% of the patients are alive. 28 patients were irradiated with gross tumour present at the time of neutron therapy (recurrence, incomplete resection, inoperable): a local control was achieved in 5/28 cases (18%), and 68% of the patients are alive. A complication rate of 16% was recorded which was directly related to the treatment volume.

Combined Modality Therapy↗
PubMed1988

[Are adolescence and institutions opposed?].

After reviewing and putting into perspective the general situation of institutions, the authors concentrate on the institutional aspects of the normal process of adolescence; the room given to psychopathological mechanisms in the transactions of certain adolescents with the institutions ; the usefulness of institutional formalization in setting up therapeutic environments and activities.

English Abstract↗
PubMed1986

[Reception of adolescents at an intersector dispensary. Retrospective study of 5 years of operation].

The study of some characteristics (clinical and sociodemographic) of a population of adolescent clients and the modes of reception and therapeutic modalities which have been proposed for them introduces a discussion on: the contributions and the limits of so-called informal modes of reception and assigning to treatment, as well as the value of taking into consideration the ways the adolescents relate to their environment; the necessity for rapid agreement and the diversity of the observed evolutions which justify both the need for adequate identification of immediate movement and for a dynamic perspective; and, after considering the adequacy of the gathered information for our way of thinking and practicing, the pertinence of an epidemiological evaluation and its utility for clinicians.

Adolescent↗
PubMed1986

Current results of neutron therapy at the UCL, for soft tissue sarcomas and prostatic adenocarcinomas. Université Catholique de Louvain.

From March 1978 to August 1985, 630 patients were treated with fast neutrons at the UCL cyclotron of Louvain-la-Neuve. Neutrons are produced by bombarding a beryllium target with 65 MeV protons. A CNPF of 2.8 was adopted. As far as soft tissue sarcomas are concerned, 32 patients were irradiated after "radical" surgery: only 2 local recurrences were observed (follow-up from 6 months to more that 5 years). On the other hand, in a group of 26 patients with large inoperable, recurrent of incompletely resected tumours, local control could not be achieved in 14 cases. In the whole group of these 58 patients, 12 severe complications were observed; their frequency increases with field size which in turn reflects tumour extent. Locally extended prostatic adenocarcinomas (stage C) were treated with mixed schedule irradiation (3 neutron and 2 photon fractions per week). A local control rate of 93% at 1 year, of 83% at 2 years, and 90% at 3 years was achieved (28, 23 and 10 patients respectively). The early and late tolerance was excellent; only one complication was observed.

Adenocarcinoma↗