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Biomedical subjects

J Luc

Publications and source records attributed to J Luc.

8 recordsLinked to original sources
PubMed2005

Third-order nonlinear optical figure of merits for conjugated TTF-quinone molecules.

We have revealed a substantial enhancement of third-order optical figure of merits by the synthesis of a compact molecule possessing the tetrathiafulvalene (TTF) group with two backside C=O groups. Addition of the saturated methylene chain substantially suppresses the third-order optical figure of merits and even local optical hyperpolarizabilities at lambda = 532 nm. Another TTF-derivative molecule possessing ethylenic and acetylenic chains demonstrates large hyperpolarizabilities; however, generally, the figure of merit factor decreases due to the increasing optical losses as a consequence of enhanced linear absorption. At the same time, both of the chromophores have a large nonlinear optical response. General approaches for search and design of the third-order optical materials with improved properties are given.

Journal Article↗
PubMed1997

Automatic washer disinfector for flexible endoscopes: a new evaluation process.

BACKGROUND AND STUDY AIMS: Many automatic washer disinfectors for flexible endoscopes have been marketed and offered as an alternative method of preventing infections, but they are frequently unsatisfactory. There is therefore clearly a need to test prototypes prior to marketing, following an evaluation process that is sufficiently reliable and rigorous to guarantee the efficacy of the decontamination processes. MATERIALS AND METHODS: The present study describes an experimental method based on the follow-up of the decontamination of a Tygon tube, the internal surface of which was contaminated by a bacterial biofilm. This method is proposed as a preliminary test for evaluating washer disinfectors. RESULTS: An analysis of the results obtained after technical modifications of the first prototype of the Fibro-Cleaner showed that complementary activities of each successive cycle phase allow a reduction in the number of adherent bacteria of more than 8 log per cm2 of support. With the three different biofilms tested (Escherichia coli, Pseudomonas aeruginosa mucoid and Staphylococcus aureus), no microorganisms were recovered from the support at the end of the decontamination process. CONCLUSIONS: The experimental protocol suggested here seems to be well suited for assessing washer disinfectors during the development phase of the prototype, as well as for comparative studies.

Biofilms↗
PubMed1993

[Chlorhexidine digluconate/chlorocresol combination. In vitro study of interactions observed against potential cutaneous strains].

The interaction type of chlorhexidine digluconate/chlorocresol association (foaming solution DC 102/1, Laboratoires Pierre Fabre Médicament) have been studied according to the chess-board method, on microplate, by determining MBC (Minimal Bactericidal Concentrations) (or MFC (Minimal Fungicidal Concentrations)) adjusted to T 72-150 AFNOR norm (dilution-neutralization, contact 5 mn) and computation of FBC (or FFC) Index. Trials were carried out against 18 hospital strains (Staphylococcus epidermidis, Staphylococcus aureus, Propionibacterium acnes, Candida albicans) and against 4 strains of the AF-NOR norm. MBC of chlorhexidine, against Staphylococci were included between 6.25 and 25 micrograms/ml, and between 25 and 200 micrograms/ml against the others strains. MBC of chlorocresol were included between 800 and 3,200 micrograms/ml. Against the 22 tested strains, 18 synergistic interactions (FBC Index < or = 0.75) were observed, with 4 to 8 reducing factor for chlorhexidine, and > or = 2 for chlorocresol. No antagonism was noted (maximal FBC Index = 1).

Candida albicans↗
PubMed1992

Immunostimulant effects on granulocyte functions during an acute respiratory infection.

Treatment of healthy volunteers by Ribomunyl, whether or not in association with in vitro antibiotics (amoxicillin or josamycin), has been earlier demonstrated to be an efficient stimulant of PMN functions (adhesion and migration). This second double-blind study versus placebo was performed on 17 patients with acute respiratory infections (placebo group: eight subjects; Ribomunyl group: nine subjects). Ribomunyl treatment (four days) associated with antibiotherapy (amoxicillin) induced a significant increase of PMN adhesion (p = 0.014) with no significant effect of the placebo (p = 0.30) and no significant difference between the initial level of PMN adhesion of the two groups (placebo-Ribomunyl).

Adolescent↗
PubMed1991

Effect of an in vivo immunostimulant treatment on PMN functions: interaction with antibiotics in vitro.

The in vivo effect of immunostimulant treatment, bacterial ribosomes together with membranal proteoglycans (three tablets and three sprays daily during 4 days) in combination or not with in vitro amoxicillin or josamycin (range 5-50 micrograms/ml), has been studied on three related functions of polymorphonuclear cells (PMN) isolated from human blood: adhesion, spontaneous and oriented migration. The immunostimulant treatment always induces an increase of the three parameters. A positive effect of high concentrations of amoxicillin could be also observed on adhesion and gives rise to a great additional impact by associating it with immunostimulant treatment (control: 8.26 PMN/field; assay: 51.55 PMN/field). Spontaneous and oriented migration are not very altered by in vitro antibiotics. A very significant decrease of chemotaxis has been only observed with 50 microgram/ml of josamycin. However, the immunostimulant treatment compensates for this negative effect. The real increase in PMN activation produced by the immunostimulant treatment might extend its indications beyond prevention during antibiotherapy, for example in the acute phase of respiratory infections.

Adjuvants, Immunologic↗
PubMed1991

Ciclopirox nail lacquer 8%: in vivo penetration into and through nails and in vitro effect on pig skin.

This report presents original methods to assess the bioavailability of an antifungal drug from a varnish preparation in finger nails. For the studies with human volunteers a ciclopirox 8% nail lacquer was used to determine its efficacy in the treatment of onychomycoses. In vivo studies were performed on the fingernails of healthy volunteers by determining the total amount of ciclopirox penetrated per milligram of nail and the partition of the drug in the plate of the nails (technically divided into four layers). Ciclopirox concentrations were evaluated by measuring the inhibition of Candida pseudotropicalis growth in vitro. The ciclopirox concentration after 30 days treatment was determined as 3.35 +/- 0.82 micrograms/mg nail material. This is a sufficient amount to kill the fungal pathogens. In addition, in vitro penetration experiments were carried out with excised pig skin. Lacquer formulations from 0.5 to 8% were used to inhibit the growth of Trichophyton mentagrophytes. Formulations from 2 to 8% led to a strong to total inhibition of the dermatophyte after 30 min treatment time.

Administration, Topical↗
PubMedDate not supplied

[The bactericidal activity of mouthwashes containing 0.10%, 0.12% and 0.20% chlorhexidine digluconate].

Antiseptic activity of five mouthrinses containing 0.10%, 0.12% and 0.20% chlorhexidine, as well as aqueous chlorhexidine solutions at the same concentrations were determined under usual conditions (advocated dilutions by the manufacturers and short contact time) and according to French Pharmacopoeia recommendations. The three aqueous solutions and two mouthrinses containing 0.12% chlorhexidine were not antiseptic according to the fixed criteria. Bactericidal activities of the different dilutions of products were tested with an appropriate micromethod against nine-bacterial species involved in periodontal disease. Efficacity of mouthrinses were variable and were not agreed with the aqueous chlorhexidine-corresponding solutions: the mouthrinse containing 0.10% chlorhexidine reached 0.20% aqueous solution efficacy, and the mouthrinses containing 0.12% chlorhexidine were generally less active than the 0.12% aqueous chlorhexidine solution. Therefore, antibacterial activity of this type of product cannot be anticipated with the sole concentration factor, excipients playing essential part in the chlorhexidine activity.

Anti-Bacterial Agents↗