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C Roques

Publications and source records attributed to C Roques.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1997

Influence of trophic conditions on exopolysaccharide production: bacterial biofilm susceptibility to chlorine and monochloramine.

This study examines the controversial efficacy of chlorine and monochloramine against biofilms that differ in their extracellular polysaccharide (EPS) content. The results point out a net variability of bacterial biofilm susceptibility according to the nutrients present. Chlorine and monochloramine showed an equal biocidal activity on lactose medium-grown E. coli ATCC 10536 and glycerol-ammonium nitrate medium-grown nonmucoid Pseudomonas aeruginosa biofilms. In contrast, the effect of monochloramine is greater compared with that of chlorine on E. coli and mucoid P. aeruginosa biofilms grown in sucrose and glycerol-ammonium nitrate media, respectively. In these culture conditions, treatment with 25 mg monochloramine/L for 2 h reduced culturable cells by 4.5 logs (99.997%) for E. coli and about 3 logs (99.87%) for mucoid P. aeruginosa while the similar treatment with chlorine reduced culturable cells in these biofilms by 2.2 logs (99.4%) and 1 log (10%), respectively. The decrease of chlorine disinfection efficacy on sucrose and glycerol-ammonium nitrate medium-grown biofilms is postulated to be linked to the higher polysaccharide production observed in these media. It seems likely that monochloramine produces a high leakage of material absorbing at 260 nm from sucrose medium-grown E. coli biofilm, which could indicate its better penetration into biofilms.

Biofilms↗
PubMed1997

Inhibition of Streptococcus pneumoniae adhesion by specific salivary IgA after oral immunisation with a ribosomal immunostimulant.

Oral 'Ribomunyl' has been shown to increase levels of specific salivary IgA. The ability of specific salivary IgA to inhibit the adhesion of Streptococcus pneumoniae to buccal epithelial cells was investigated in vitro using 13 saliva samples from healthy volunteers who received 'Ribomunyl' therapy for 3 weeks. The S. pneumoniae strain contained in 'Ribomunyl' was [3H]thymidine-labelled and pretreated with dilutions of saliva for 1 hour at 37 degrees C. Bacterial adhesion was measured after 2 hours' contact with human oral epidermal cell monolayers at 37 degrees C under CO2. Nonadherent bacteria were washed off, and the residual radio-activity of the monolayers was compared with that of bacteria not pretreated with saliva. A significant decrease (p < 0.05) in S. pneumoniae adhesion was observed with 6 saliva samples with high levels of specific IgA. This decrease was seen at all dilutions from 1/5 to 1/1000. In contrast, no significant modification of adhesion was seen in the 7 saliva samples with unmodified levels of IgA. These data demonstrate that the increase in salivary IgA levels during 'Ribomunyl' therapy was linked with the capacity of saliva samples to specifically and efficiently inhibit adhesion of S. pneumoniae to buccal epithelial cells in vitro.

Adjuvants, Immunologic↗
PubMed1996

Comparison of antimicrobial properties of monoterpenes and their carbonylated products.

Some monoterpenes and their carbonylated products were evaluated for their antibacterial and antifungal properties. The carbonylation of tested monoterpenes was shown to increase the bacteriostatic and fungistatic activities specifically by the contact method. Concerning the killing effects, only (1R,2S,5R)-isopulegol, its carbonylated products, and (R)-carvone showed significant bactericidal activities, particularly against Enterococcus faecium and Escherichia coli above a concentration of 10 microliters/ml. A fungicidal efficiency of (1R,2S,5R)-isopulegol and (R)-carvone against Aspergillus niger was also noted. It seems that the presence of an oxygenated function in the framework increases the antimicrobial properties. However, monoterpenes were more active using a micro-atmosphere method.

Anti-Bacterial Agents↗
PubMed1994

Termination of pregnancy for maternal toxoplasmosis.

Termination of pregnancy is usually recommended to pregnant women who have infection with Toxoplasma gondii before 26 weeks of pregnancy if the fetus is infected. No prospective studies are available on the outcome if such pregnancies are allowed to continue with anti-parasitic treatment. We prospectively studied 163 mothers with acute toxoplasma infection before 28 weeks of amenorrhoea. All received anti-parasitic treatment with 9 million IU spiramycin orally. 23 also received pyrimethamine and sulphadiazine. All had cordocentesis and regular obstetric ultrasound examinations. The 162 liveborn infants were followed up for 15 to 71 months. 3 fetuses died in utero. 27 of 162 liveborn infants had proven congenital toxoplasmosis: 10 had one or more clinical signs of congenital toxoplasmosis; 5 had isolated or multiple intracranial calcifications; 7 had peripheral chorioretinitis; and 2 had moderate ventricular dilations. All 27 are free from symptoms and have normal neurological development at 15 to 71 months of age. We conclude that in first and second trimester pregnancies with acute fetal toxoplasma infection, the pregnancy need not be interrupted if repeated fetal ultrasound is normal, and antiparasitic treatment is given.

Abortion, Eugenic↗
PubMed1994

An in vitro mouth model to test antiplaque agents: preliminary studies using a toothpaste containing chlorhexidine.

The development of an in vitro model simulating the oral cavity has allowed the antiplaque activity of a toothpaste containing 0.004% chlorhexidine to be tested. The model is based on the continuous irrigation of bovine tooth samples with artificial saliva. Scanning electron microscopy showed homogeneous colonization of monobacterial plaque by Streptococcus mutans on dental surfaces under these model conditions. The enamel was colonized with regular cell clusters showing a globular appearance. The globules coalesced with increasing plaque thickness. Treatment with toothpaste containing 0.004% chlorhexidine showed a more marked inhibition of bacterial colonization on enamel surfaces than placebo paste lacking this antimicrobial agent. These results indicate that the toothpaste formulation is compatible with chlorhexidine. It is concluded that the in vitro model developed in this study is suitable for the testing of the antiplaque activity of antimicrobial agents, particularly when in a semisolid form such as in a toothpaste.

Animals↗
PubMed1994

[Sporocidic activity of sodium hypochlorite and peracetic acid alone or combined against free or fixed spores or on biofilm].

In order to assess the sporocidal activity of chlorine and peracetic acid (PAA), alone and in combination, against a spored biofilm, the biofilms of two species (Bacillus subtilis ATCC 6633 and Bacillus megaterium ATCC 8245) were formed on inert support (tygon). A sporulation kinetic of these bacteria in biofilm was established. Sporocidal properties of chlorine and PAA were compared against free spores, spores fixed by drying and spores in biofilm. The combination of these two products was also tested. Minimal sporocidal concentrations (MSC) of the two products towards free spores were determined (contact time 5 mn). The efficacy of these MSC were evaluated in terms of contact time on adhered spores and on spores in biofilm. Chlorine and PAA exhibited an excellent sporocidal activity. The combination of PAA and chlorine, tested by checkerboard micromethod, was found to be synergistic in case of free or adhered spores. The spored biofilm showed a high resistance. The combination of these two products revealed then only an additive effect.

Bacillus megaterium↗
PubMed1994

[Medical and economic aspects of handicaps].

Handicap has heavy economic implications. Pensions, whose the amount is about 127 billions of french francs, are paid, every year, to disabled persons. But the medical charges of these persons, paid by the social security, are not established, nor the wealth undoing. On the other hand, a lot of jobs are run to take care of the handicapped and many rehabilitation units and homes are devoted to them (33,000 beds) as well as adapted employment (81,000 places). The risk of dependency in the elderly has led to a deep change in the allocation of many savings. Rehabilitation cost-effective programs are contributive to reduce handicaps; significant demonstrations has been given for many common diseases as low back pain, post-stroke hemiplegia, osteoporosis.

Persons with Disabilities↗
PubMed1994

[Comparative in vivo and in vitro study of bacterial colonization by Streptococcus mutans on dental surfaces in axenic rats and in an artificial model of the oral cavity].

The study of bacterial colonization by Streptococcus mutans on dental surfaces of rat have been undertaken in vivo in gnotobiotic rat, and in vitro in an artificial mouth model, in order to validate the suitability of such a model. The study of colonization by Streptococcus mutans with time showed a similar kinetic of the monobacterial plaque formation in the two experimentations. Three phases were observed. A logarithmic phase in the earliest hours after inoculation of bacterium, followed by an exponential phase, and finally a stabilization phase of the monobacterial plaque formed in this way from the third day. Nevertheless, if the kinetic is the same, it is observed a more important colonization of dental surfaces in rat. This phenomenon was explained by the simplification of biological conditions encountered in the in vitro model. In particular, it is noticed the important saliva action. It is concluded that the in vitro model developed simulate suitably the conditions of the oral environment encountered in vivo.

Animals↗
PubMed1993

Importance of the paracellular pathway for the transport of a new bisphosphonate using the human CACO-2 monolayers model.

The transport of a new bisphosphonate, Tiludronate, was investigated on the human adenocarcinoma cell line, CACO-2. Experiments were performed 7-16 days after cells achieved confluence, conditions under which they form well-differentiated monolayers joined by tight junctions. Tiludronate transport rate across CACO-2 monolayers was independent of the temperature (4 degrees versus 37 degrees), of the polarity of the cell membrane (apical-to-basolateral versus basolateral-to-apical), and of the presence of metabolic poisons (sodium azide). Its transport was enhanced by either the presence of EGTA in the incubation buffer, i.e. when extracellular Ca2+ concentration was reduced, or by the pretreatment of monolayers with EGTA, i.e. when the intercellular spaces and the tight junctions were widened. Based on these different observations, we could suggest that Tiludronate mainly used the paracellular pathway to cross the intestinal epithelium. An increase in the Tiludronate permeability coefficient was also observed following treatment of cells with high Tiludronate concentrations, as a consequence of the direct effect of this compound on the extracellular Ca2+ ions. Hence, for high drug concentrations, i.e. 20 mM, we observed a decrease in free extracellular Ca2+ concentration, an increase in the transepithelial electrical resistance and an increase in the transport of [14C]polyethyleneglycol ([14C]PEG400), a probe for the paracellular pathway. The results indicate that Tiludronate is transported across CACO-2 monolayers by the paracellular route. Moreover, it can affect its own transport by its concentration-dependent effect on tight junction widening.

Azides↗
PubMed1993

In vitro stimulation of polymorphonuclear cell adhesion by ribomunyl and antibiotic + ribomunyl combinations: effects on CD18, CD35 and CD16 expression.

Several functions of polymorphonuclear cells (PMNs) require adhesion to occur. Various membrane proteins' functions such as CD18 (beta 2 chain of integrin), CD35 (CR1) and CD16 (F c gamma Receptor III) participate in adhesion. In vivo treatment with Ribomunyl (R), an immunomodulating agent, was shown to enhance adhesion and migration of PMNs. To explore the direct effect of R on PMNs, cells from healthy subjects were treated in vitro with R. A significant increase of PMN adhesion and expression of CD18 and CD35 molecules were observed with 50 and 100 micrograms/ml of R after 2 h incubation. However, R-treatment decreased the PMN reactivity towards anti-CD16 (F c gamma RIII) monoclonal antibody. The effect of R on adhesion and membrane molecule expression was independent of the presence of serum and of polymixin B. Thus, this effect cannot be due to lipopolysaccharide (LPS) contaminants and does not require interactions with serum components. In previous studies, it was shown that in vitro amoxicillin increased some PMN functions whereas josamycin decreased them. The in vitro incubation of PMNs with R and amoxicillin (100 micrograms/ml) potentiated the positive effect of amoxicillin on adhesion and the antibiotic counterbalanced the negative effect of R on CD16 expression. In addition, R compensated the negative effect of josamycin (100 micrograms/ml) on PMN adhesion and on CD18 and CD35 expression. This study indicates: (1) the direct effect of R on PMN adhesion and on expression of molecules involved in adhesive-mediated functions, and (2) the beneficial effect of the association of R with antibiotics which can stimulate PMN activity.

Adjuvants, Immunologic↗
PubMed1993

Sporocidal properties of peracetic acid and hydrogen peroxide, alone and in combination, in comparison with chlorine and formaldehyde for ultrafiltration membrane disinfection.

The sporocidal properties of peracetic acid, hydrogen peroxide, chlorine, and formaldehyde were compared in vitro using a dilution-neutralization micromethod. A combination of peracetic acid and hydrogen peroxide was also tested to assess their interactions. The activities of these agents, which are widely used as disinfectants, were evaluated against Bacillus spore isolates found on stored membranes and collection cultures. Peracetic acid and chlorine exhibited an excellent antimicrobial activity, with a destruction of 10(5) spores/mL after 5 min of contact. Generally the effects of the biocides tested were time dependent. The sporocidal activities of hydrogen peroxide and formaldehyde were the lowest. The combination of peracetic acid and hydrogen peroxide, tested by a checkerboard micromethod, was found to be synergistic. The minimal sporocidal concentration (MSC) was established in terms of time for each biocide. The lowest MSC values for peracetic acid, hydrogen peroxide, chlorine, and formaldehyde were 168-336 ppm (1-2 h of contact), 5625-11250 ppm (5-7 h), 168-336 ppm (2-3 h), and 1875-3750 ppm (5-30 min), respectively. The MSC of a biocide combination of peracetic acid and hydrogen peroxide showed that synergy was maintained with increasing contact time and that the MSC could be reduced by two to eight times when compared with those of the biocides alone. Optimal concentrations and contact times of those chemicals that were promising in vitro were then tested for their ability to disinfect ultrafiltration membranes. The sporocidal activities of peroxide compounds and chlorine were confirmed and the synergism between peracetic acid and hydrogen peroxide was also maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacillus↗
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↗
PubMed1993

[Antenatal diagnosis of toxoplasmosis. 176 case reports].

OBJECTIVE: To determine the value of antenatal diagnosis of congenital toxoplasmosis by ultrasound guided aspiration of cord blood for testing. MATERIAL: This is a prospective study of 176 cases. As well as obtaining fetal blood and amniotic fluid the searched for specific IgM and A as well as culturing for the parasites on human fibroblasts and inoculation of mice, as well as researching them for non-specific signs of fetal infection. 149 children were able to be followed up one year after birth. RESULTS: 15% of the children (22/149) were infected with toxoplasmosis. 11 out of these were diagnosed positive antenatally. For the 11 others the diagnosis of fetal infection could only be made after birth, but the non-specific signs made it possible to expect early that they had been contaminated. 59% (13/22) had latent toxoplasmosis which only showed up after a mean interval of 34 months after birth. 41% (9/22) had clinical and/or paraclinical signs of toxoplasmosis (mainly unilateral non-macular chorioretinitis and intracranial calcifications) but they are well after a follow-up period averaging 30 months. COMMENTARY: Ultrasound alone, when it shows up fetal abnormalities, can make the diagnosis of the severity of the condition. The role of taking fetal specimens is to make clear those infants that are infected because of specific signs, and to find those fetuses which are at high risk because of non-specific signs in order to improve the management of the cases. This development has made it possible to avoid carrying out a large number of unnecessary terminations of pregnancy and has resulted in the birth of affected infants that had no functional sequelae from the infection.

Amniotic Fluid↗
PubMed1992

IgA antibody response during acquired and congenital toxoplasmosis.

Toxoplasma gondii specific IgA and IgM antibodies were quantitated by an antibody capture agglutination assay in 260 patients with acquired toxoplasmosis and from 94 fetuses suspected of congenital toxoplasmosis and 30 infected children. In acquired toxoplasmosis, IgA antibodies to T gondii were found in 95% of the cases. In congenital toxoplasmosis IgA antibodies were more frequently detected (75%) in cord blood than IgM antibodies (61%). They persisted after birth, in some cases for up to 24 months. IgA antibodies were also detected in fetuses whose mothers had toxoplasmosis during their pregnancy. In infected fetuses IgM and IgA antibodies were detected in fetal blood as early as week 24 of pregnancy. Detection of IgA T gondii antibodies may be useful for the diagnosis of some recently acquired infection and for the diagnosis and follow up of the infection in the fetus and neonate.

Adult↗
PubMed1992

Bactericidal properties of peracetic acid and hydrogen peroxide, alone and in combination, and chlorine and formaldehyde against bacterial water strains.

The bactericidal properties of peracetic acid, hydrogen peroxide, chlorine, and formaldehyde were compared in vitro using a rapid micromethod. A combination of peracetic acid and hydrogen peroxide was also tested to assess interactions. The activities of these agents, which are widely used as disinfectants, were evaluated against water isolates and culture collection strains. Peracetic acid and chlorine exhibited an excellent antimicrobial activity, with a relatively rapid destruction of 10(5) bacteria/mL. The time-dependent bactericidal activities of hydrogen peroxide and formaldehyde were the lowest. The combination of peracetic acid and hydrogen peroxide, tested by a checkerboard micromethod, was found to be synergistic. The minimal bactericidal concentration was established in terms of time for a given mixture of peracetic acid and hydrogen peroxide. Determination of bactericidal concentrations showed that synergy was maintained with increasing contact time. Concentrations for minimal times of treatment by chemicals that provided interesting activities in vitro were tested for disinfection of ultrafiltration membranes. The bactericidal activities of peroxygen compounds were confirmed and synergism was maintained in working conditions. Chlorine showed a loss of efficacy when used on membranes.

Chlorine↗
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↗