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J Cottin

Publications and source records attributed to J Cottin.

18 recordsLinked to original sources
PubMed2004

Assessment of new chemical disinfectants for HBV virucidal activity in a cell culture model.

Several new chemical disinfectants were processed for Hepatitis B virus (HBV) virucidal activity in a cell culture model. A pooled HBV infected human plasma with 10(10.4) HBV DNA copies/mL was treated with the tested disinfectant. It was then subjected, for three days at several dilutions, to cell culture using the human hepatoma cell line, HepG2, with 4% polyethyleneglycol and 3 mM sodium butyrate. Thirty-seven assays were performed on 12 products, with up to 3 concentrations and 3 time exposures for each product tested. The mean viral titre without disinfectant was 10(5.18) infectious units per mL. Our results showed that products all four hand rubs examined, two of the three surface disinfectants and two of the three instrument disinfectants were highly active whatever concentrations and time exposures, reducing viral times by factors of 10(3)-10(4). However, other products such as one of the surface disinfectants was only active at concentrations above 0.5% for 15 min. Similarly the skin disinfectant, one of the instrument disinfectants and the hand wash agent (diluted to 50%) were less or not active (of <10(3) fold reduction). This is the first study using a cell culture model to assess virucidal activity against HBV of new disinfectants. It showed that most 9/12 products were active by either HBs antigen alteration (8/9) or probable envelope disruption (1/9). Further studies are in progress using this model to assess the activity of other chemical disinfectants such as peracetic acid against HBV.

Cell Line↗
PubMed2001

[Cat scratch disease. Clinical study of 26 patients. Role and importance of PCR].

PURPOSE: Cat scratch disease is a mild pathology but diagnosis often remain difficult. METHODS: A retrospective study has been conducted by the department of infectious diseases at the University hospital in Angers. Between January 1994 and October 1998, 26 observations were recorded providing the presence of three criteria out of four among the following: contact with a cat, clinical presentation and its favorable course, absence of any other cause noticed, and the presence of either a positive serology or a positive PCR, or the examination of a suggestive pathology. RESULTS: Fourteen men and 12 women were concerned. From a clinical point of view, the inoculation lesion was observed six times, all patients showed at least one adenopathy during their illness, 12 patients showed only an adenopathy without clinical signs. A surgical biopsy was carried out on nine patients and a diagnosis established. Bartonella henselae serology was done in all patients. Six presented a significant rate of IgG antibodies as early as the first dosage. A seroconversion was observed in four cases belatedly 1 to 2 months after the beginning of the symptomatology. The method's sensitivity was approximately 38%. A PCR search was accomplished in the pus obtained from a ganglionic puncture on 12 patients. It was positive seven times, which corresponds to a sensitivity of about 58%. In associating these two diagnostic criteria a sensitivity rate of nearly 92% was reached, the diagnosis not having been confirmed only in one case. The outcome proved to be favorable in all cases, with or without an antibiotic treatment. CONCLUSION: The association of serology and PCR in the pus permits a certain diagnosis in the majority of the cases and avoids the more aggressive biopsy.

Adolescent↗
PubMed2001

Transcript profiling in Candida albicans reveals new cellular functions for the transcriptional repressors CaTup1, CaMig1 and CaNrg1.

The pathogenic fungus, Candida albicans contains homologues of the transcriptional repressors ScTup1, ScMig1 and ScNrg1 found in budding yeast. In Saccharomyces cerevisiae, ScMig1 targets the ScTup1/ScSsn6 complex to the promoters of glucose repressed genes to repress their transcription. ScNrg1 is thought to act in a similar manner at other promoters. We have examined the roles of their homologues in C. albicans by transcript profiling with an array containing 2002 genes, representing about one quarter of the predicted number of open reading frames (ORFs) in C. albicans. The data revealed that CaNrg1 and CaTup1 regulate a different set of C. albicans genes from CaMig1 and CaTup1. This is consistent with the idea that CaMig1 and CaNrg1 target the CaTup1 repressor to specific subsets of C. albicans genes. However, CaMig1 and CaNrg1 repress other C. albicans genes in a CaTup1-independent fashion. The targets of CaMig1 and CaNrg1 repression, and phenotypic analyses of nrg1/nrg1 and mig1/mig1 mutants, indicate that these factors play differential roles in the regulation of metabolism, cellular morphogenesis and stress responses. Hence, the data provide important information both about the modes of action of these transcriptional regulators and their cellular roles. The transcript profiling data are available at http://www.pasteur.fr/recherche/unites/RIF/transcriptdata/.

Candida albicans↗
PubMed2001

Inactivation of hepatitis B virus in plasma by hospital in-use chemical disinfectants assessed by a modified HepG2 cell culture.

Because of the difficulties of the chimpanzee model and the genetic differences using the duck model, we developed a cell culture method to measure human hepatitis B virus (HBV) inactivation in vitro. Pooled HBV-infected human plasma that had been exposed to a disinfectant was left in contact for three days with a cell culture of the human hepatoma cell line, HepG2, with 4% polyethyleneglycol and 3 mM sodium butyrate. The mean log10 of the viral titre of unexposed plasma was 4.87 infectious units per mL. Our results showed that 1% glutaraldehyde, sodium hypochlorite at 4700 ppm free chlorine and an iodophor-detergent disinfectant containing 3.6% povidone-iodine reduced viral titres by factors exceeding 10(3)-10(4). However, sodium hypochlorite at 1000 ppm free chlorine had minimal activity and povidone-iodine at 9, 5 and 3.6% had no measurable activity (less than 10-fold reduction). This is the first study using a cell culture model to assess disinfectant activity against HBV. It demonstrates more rapidly than the chimpanzee model that glutaraldehyde and sodium hypochlorite, using standard concentrations and exposure times compatible with clinical practice, were highly active against HBV. However, unexpectedly for an enveloped virus, we found no antiviral activity for iodine in the absence of detergent.

Blood↗
PubMed2001

[Pneumococcal antibiotic resistance. Data from 6 regional registries for 1999].

RESISTANCE BY REGION: Resistance varied greatly by region, ranging from 34.2% resistant strains in Alsace to 63.1% in Brittany. The incidence of resistant strains was always higher in children (especially in children aged 1 to 5 years) and in ENT samples. The time course of resistance has varied between regions, as has that of serotypes. CRUCIAL FINDING: In these 6 regions, and despite a high incidence (that varied from one region to another) of reduced susceptibility strains for penicillin G, amoxicillin (19-32%) and cefotaxime (6.5-18.5%), amoxicillin-cefotaxime resistant strains remained very rare (0.2-3.5%).

Age Distribution↗
PubMed2000

Adherence of platelets to Candida species in vivo.

The in vivo interactions of platelets with Candida species yeast cells were investigated in a murine model. Mice were injected intravenously via the lateral caudal vein, and blood drawn by periorbital puncture was collected in phosphate-buffered saline-formaldehyde to avoid in vitro platelet activation. The study of the clearance of blastoconidia of Candida albicans and Candida glabrata showed that these cells disappeared quickly from the bloodstream. Microscopic observation of blood samples, stained by Calcofluor white or May Grunwald Giemsa, demonstrated the rapid attachment of platelets to fungal elements of all the Candida spp. tested. The attachment of murine platelets to C. albicans cells, observed by scanning electron microscopy, revealed morphological changes. The platelets lost their discoid shape, generated pseudopodia, and flattened against the yeast cells. The reversibility of platelet binding to C. albicans by chelating agents suggests a cation-dependent link. In contrast, the fixation of C. glabrata and Candida tropicalis was not modified by chelating agents. The mechanisms involved in the in vivo adherence of platelets to Candida cells may therefore differ according to the species of Candida.

Adhesiveness↗
PubMed1995

Development and characterization of monoclonal antibodies specific for the genus Listeria.

Monoclonal antibodies were obtained by the classic hybridoma technique with lymphocytes of BALB/c mice immunized with formalin killed Listeria monocytogenes cells. Among 1000 hybridomas issued from the fusion, four monoclonal antibodies (mAbs A6 A E4, C10 A F7, G4 A D6, G7 A D5) gave interesting results. By Western-blot analysis with various soluble extracts of different Listeria species, the four mAbs reacted with two major antigens of 38 and 41 kDa, with all Listeria species tested. The mAb A6 A E4 is an IgG2b with kappa light chains and reacted only with Listeria antigens without any cross reaction with other organisms tested by ELISA, dot-blotting and Western-blotting. With the same conditions, the three other mAbs reacted with Listeria and with other genus extracts, particularly with Streptococcus and Enterococcus. mAb A6 A E4-reactive antigens are proteins, and glycoprotein immunoassay indicated that the epitope is devoid of carbohydrate moiety. This mAb A6 A E4-reactive protein was neither expressed on cell surface nor released outside the bacteria; immunogold electron microscopy showed that these antigens were localized in the cytoplasma area.

Animals↗
PubMed1991

Specific interaction between Listeria monocytogenes and glycosylated albumins.

We have previously shown that Listeria monocytogenes serovar 1/2b can bind strongly to bovine albumin (BA) glycosylated by glucosamine or fucosylamine with about 20 to 30 carbohydrate residues per albumin molecule. We now show that the binding is time-dependent, reversible, saturable and specific. The two glycosylated compounds inhibit each other competitively. Scatchard analysis showed that about 100 molecules of BA-glucosamide (heptameric configuration) and 14,300 molecules of BA-fucosylamide (monomeric configuration) bound per bacterial cell. The apparent dissociation constants for BA-glucosamide and BA-fucosylamide were found to be 3.9 x 10(-14) M and 3.5 x 10(-13) M, respectively.

Albumins↗
PubMed1991

Specific binding of neoglycoproteins to Toxoplasma gondii tachyzoites.

Several studies have shown that protozoa bind to glycoproteins or neoglycoproteins. Here we report that Toxoplasma gondii binds strongly to bovine serum albumin-glucosamide. The binding was rapid, time dependent, partially reversible, saturable, and specific. Scatchard analysis showed about 40,000 molecules of bovine serum albumin-glucosamide per toxoplasma cell. The apparent dissociation constant was found to be 4.46 x 10(-8) M.

Animals↗
PubMed1990

Surface Listeria monocytogenes carbohydrate-binding components revealed by agglutination with neoglycoproteins.

Carbohydrate-binding components were shown to be present at the surface of Listeria monocytogenes by means of a panel of neoglycoproteins using direct agglutination. These lectin-like components bind on neoglycoproteins bearing D-glucosamine, L-fucosylamine, or para-amino-phenyl-alpha-D-mannopyrannoside residues. The interactions were inhibited by the carbohydrate moieties specific to the neoglycoproteins. The protein nature of the lectin-like components of L. monocytogenes was ascertained by the loss of carbohydrate-binding capacity following protease treatment.

Agglutination Tests↗
PubMed1990

Study of Listeria monocytogenes survival during the preparation and the conservation of two kinds of dairy product.

We tested yoghurts and soft cheeses for survival of Listeria monocytogenes during their manufacture and their storage at 4 degrees C. In yoghurt, even when the concentration of germs is high, the bacterial population decreased rapidly and the life of time of L. monocytogenes in this product depends on the sample acidity. The microorganisms disappear when the pH falls to 3.5. In soft white cheeses, only a fabrication with chemical and bacterial ferments allows an acidity which is compatible with destruction of majority of L. monocytogenes. Under these conditions, the pH decreases to 4-4.5 according to the series of production.

Cheese↗
PubMed1989

Persistence of Listeria monocytogenes in three sorts of soil.

Life time of Listeria monocytogenes (strain PS 10401, serovar 4b) was studied in three sorts of soil: a chalky soil, poor in organic matters (pH 8.3) a peaty soil rich in organic matters (pH 5.5) a mixture of a chalky and peaty soil (pH 7.9). About 10(5) colony forming units (c.f.u.) per g of dry material were inoculated to each sort of soil which was incubated at 4 degrees C or at 20 degrees C. Periodically samples were taken and a numeration of germs was made on Tryptose Soy Agar. When direct numeration was negative, an enrichment was made at low temperature. In peaty soil, L. monocytogenes disappeared after incubation of 162 days at 4 degrees C and 156 days at 20 degrees C. In chalky soil, L. monocytogenes disappeared after 394 days of incubation at 20 degrees C, whereas at 4 degrees C, 10(4) c.f.u./g of dry matter were found 1500 days later. In mixture of chalky and peaty soil, 10(4) c.f.u. were found 1500 days after inoculation at 4 degrees C whereas 10(3) c.f.u. were found at 20 degrees C. Acid soils do not allow the persistence of L. monocytogenes for more than 160 days. Low temperature are significantly favourable to the persistence of L. monocytogenes.

Listeria monocytogenes↗
PubMed1989

Preservation of the virulence of Listeria monocytogenes in different sorts of soil.

Listeria monocytogenes (strain PS 10401, serovar 4b) whose virulence was well known, has been placed for 600 days in a sterile chalky soil (pH 8.3) and in a mixture of chalky and peaty soil (pH 7.9) and incubated at 4 degrees C and 20 degrees C. Groups of six OF1 mice were challenged by subcutaneous injection in the rear left hind foodpad with each sort of germs. Three days after inoculation, mice were killed by cervical disruption and numeration of L. monocytogenes was made in the spleen. Chemical composition of soil does not change virulence of germs. But low temperatures significantly increase virulence.

Animals↗
PubMed1979

[Epidemic of listeriosis in Western France (1975--1976)].

Cases of human listeriosis have recently increased in Western France (Maine-et-Loire and Mayenne); until 1974, there were only 15 documented cases yearly where as in 1975, there were 113 cases, and in 1976, 54 documented cases at the hospitals of Angers and Laval. Included amongst the clinical manifestations observed, were 126 cases of materno-fetal infections and 41 cases of either septicemia or meningo-encephalitis. The bacteriological study revealed a certain variability of biological characteristics examined, the overwhelming frequence of bacteria of the strain 4 b and the predictable sensitivity of this strain to antibiotics commonly employed in cases of listeriosis. The human cases were notably more frequent between January and June but their geographical distribution was not related to cases of either animal disease nor listeria that was isolated from corn silage. In this report, we propose an etio-pathological explanation for this epidemic.

Adult↗
PubMedDate not supplied

PLGA microsphere bioburden evaluation for radiosterilization dose selection.

The aim of this study was to determine the bioburden of PLGA microspheres produced by the solvent emulsion/extraction process as a means of determining an appropriate gamma-irradiation dose for sterilization. Bioburden was evaluated on the basis of ISO specifications. The analysis of initial microbial contamination was performed on blank microspheres, prepared by a non-aseptic laboratory scale process. A mean bioburden of 36.04 CFU (colony forming units)/110 mg microspheres was determined. Most of the detected germs originated from human commensal flora. According to the ISO dose-selection method, a gamma-irradiation dose of 19.6 kGy was found sufficient to ensure a sterility level of 10(-6). The effect of the selected irradiation dose on both the molecular weight of the polymer and the kinetics of 5-fluorouracil drug release from the microspheres was compared to the European Pharmacopeia recommended irradiation dose (25 kGy). This 20% reduced dose showed a lower extent of molecular weight reduction of PLGA and a better control of 5-FU release from microparticles. This can be related to reduce polymer radiation damage.

Fluorouracil↗