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Biomedical subjects

S Leroy

Publications and source records attributed to S Leroy.

At least 19 recordsLinked to original sources
PubMed2007

Monitoring of staphylococcal starters in two French processing plants manufacturing dry fermented sausages.

AIMS: The growth and survival of Staphylococcus xylosus and Staphylococcus carnosus were monitored during sausage manufacture in two processing plants. METHODS AND RESULTS: The gram-positive, catalase-positive cocci isolated from the processing plants F10 and F11 were identified by Staphylococcus-specific PCR and species-specific oligonucleotide array. In the inoculated products with starter cultures, 90% of staphylococcal strains isolated in F10 were identified as S. xylosus and 10% as S. carnosus. In F11, 77% were identified as S. xylosus and 20% as S. carnosus. Staphylococcus xylosus dominated the staphylococcal microbiota while S. carnosus survived during the process. The pulse-field gel electrophoresis analysis revealed that all S. xylosus and S. carnosus strains isolated corresponded to the starter strains inoculated. The two starter strains of S. xylosus co-dominated in the isolates from sausages of F11, whereas the strain with pattern A1 was dominant in the isolates from sausages of F10. In the environments, no S. carnosus and S. xylosus were found, whereas Staphylococcus equorum and Staphylococcus saprophyticus were the main species isolated. CONCLUSIONS: This work highlighted the domination of S. xylosus starter strains, which showed a strong capacity to grow during sausage process, while S. carnosus survived during the process. SIGNIFICANCE AND IMPACT OF THE STUDY: Successful implantation of starter cultures is obviously a prerequisite for their contribution to sensorial qualities. Thus, the monitoring of the growth and the survival of S. xylosus and S. carnosus are required to guarantee a well-adapted starter culture. This study revealed that the two Staphylococcus species are suitable for manufacturing sausages in processing plants with very different capacities of production.

Animals↗
PubMed2006

Serological and molecular ecology of Listeria monocytogenes isolates collected from 13 French pork meat salting-curing plants and their products.

The purpose of this study was dual: 1. to evaluate the serotype distribution of 1028 Listeria monocytogenes isolates collected in 13 French salting factories and their products and 2. to identify sources of L. monocytogenes contamination in these factories and trace the routes of spread by PFGE (Pulsed-Field Gel Electrophoresis) typing. Serotypes 1/2a, 1/2b, 1/2c, 4b and 4e occurred. Pulsotype diversity was high among strains collected in plants and products. Furthermore, strains showing similar pulsotypes occurred on the same surfaces after an interval of at least two weeks and in unrelated factories. Forty five strains were genetically closely related to a 4b serotype L. monocytogenes strain isolated from a human clinical case of listeriosis. Our results highlighted the fact that L. monocytogenes is introduced into meat processing plants through raw meat. To overcome such contamination, suppliers of raw material should adhere to specific microbiological control measures. In addition, more attention should be focused on the appropriateness and compliance with procedures of cleaning and disinfection.

Animals↗
PubMed2006

XPS valence characterization of lithium salts as a tool to study electrode/electrolyte interfaces of Li-ion batteries.

X-ray photoelectron valence spectra of lithium salts LiBF4, LiPF6, LiTFSI, and LiBETI have been recorded and analyzed by means of density functional theory (DFT) calculations, with good agreement between experimental and calculated spectra. The results of this study are used to characterize electrode/electrolyte interfaces of graphite negative electrodes in Li-ion batteries using organic carbonate electrolytes containing LiTFSI or LiBETI salts. By a combined X-ray photoelectron spectroscopy (XPS) core peaks/valence analysis, we identify the main constituents of the interface. Differences in the surface layers' composition can be evidenced, depending on whether LiTFSI or LiBETI is used as the lithium salt.

Journal Article↗
PubMed2006

Anisotropic surface melting in lyotropic cubic crystals: part 2: facet-by-facet melting at Ia3d/vapor interfaces.

From experiments with metal crystals, in the vicinity of their crystal/liquid/vapor triple points, it is known that melting of crystals starts on their surfaces and is anisotropic. Recently, we have shown that anisotropic surface melting occurs also in lyotropic systems. In our previous paper (Eur. Phys. J. E 19, 223 (2006)), we have focused on the case of poor faceting at the Pn3m/L1 interface in C12EO2/water binary mixtures. There anisotropic melting occurs in the vicinity of a Pn3m/L3/L1 triple point. In the present paper, we focus on the opposite case of a rich devil's-staircase-type faceting at Ia3d/vapor interfaces in monoolein/water and phytantriol/water mixtures. We show that anisotropic surface melting takes place in these systems in a narrow humidity range close to the Ia3d-L2 transition. As whole (hkl) sets of facets disappear one after another when the transition is approached, surface melting occurs in a facet-by-facet type.

Anisotropy↗
PubMed2006

Surface properties and behaviour on abiotic surfaces of Staphylococcus carnosus, a genetically homogeneous species.

This work aimed to characterize the surface properties of Staphylococcus carnosus and the influence of different media on their ability to adhere and grow on industrial supports. As their colonization could be dependant of the strain, the genetic diversity of the strains was studied. The diversity of 13 strains analysed by pulsed-field gel electrophoresis revealed that the S. carnosus strains formed a homogeneous genetic group. Their surface properties, characterized by studying their affinity to solvents, were hydrophilic with a strong negative surface charge. The S. carnosus strain CIT 833 hardly adhered to polytetrafluoroethylene (PTFE) and stainless steel chips. Tryptic soy broth (TSB) was the most favourable medium for growth on stainless steel support while TSB/NaCl was better for growth on PTFE. Scanning electron microscopy (sem) showed that this strain weakly colonized both supports and did not form cell aggregates. Indeed, the strain did not synthesize polysaccharides. These results showed that S. carnosus adhered on different abiotic surfaces which are used in food factories but was not able to accumulate on these surfaces. The inability of S. carnosus to form biofilm could explain why S. carnosus is rarely isolated in meat processing environment.

Bacterial Adhesion↗
PubMed2006

Formation of biofilm by Staphylococcus xylosus.

The ability of 12 Staphylococcus xylosus strains to form biofilm was determined through the study of different criteria. Eleven out of the 12 strains were able to form biofilm, 10 preferentially on hydrophilic support (glass) and one, S. xylosus C2a, on both hydrophilic and hydrophobic (polystyrene) supports. The determination of bacterial surface properties showed that all strains were negatively charged with five strains moderately hydrophobic and seven hydrophilic. The bap and icaA genes, important for biofilm formation of some staphylococci, were searched. All strains were bap positive but icaA negative. Furthermore, S. xylosus strain C2a was studied on two supports widely used in the food industry, polytetrafluoroethylene (PTFE, hydrophobic) and stainless steel (hydrophilic) and appeared to adhere preferentially on stainless steel. Addition of 20 g/l of NaCl to Tryptic Soy Broth medium (TSB) did not improve significantly its adhesion but enhanced both bacterial growth and cell survival, which were optimum in this medium. Environmental scanning electron microscopy showed that S. xylosus C2a colonized the surface of stainless steel chips with intercellular spaces. The strain formed cell aggregates embedded in an amorphous polysaccharidic matrix. Indeed, synthesis of polysaccharides increased during growth on stainless steel chips in TSB.

Bacterial Adhesion↗
PubMed2006

[Analgesia in colon surgery. Can the use of NSAIDs reduce the opioid consumption following conventional and laparoscopic interventions?].

BACKGROUND: The goal of our study was to evaluate the morphine-sparing effect of nonsteroidal anti-inflammatory drugs (NSAIDs) following both conventional and laparoscopic colon surgery. MATERIALS AND METHODS: In this prospective, randomized clinical trial, 180 patients were assigned to three groups. Two groups received either paracetamol or parecoxib/valdecoxib in addition to piritramid via patient-controlled or nurse-controlled analgesia pump. Patients in the control group received piritramid only. The total piritramid consumption during hospital stay was recorded. RESULTS: Total opioid consumption was significantly lower in the two groups who received NSAIDs. Comparing conventional and laparoscopic surgery, the latter group had much lower opioid consumption. CONCLUSION: The use of NSAIDs following colon surgery significantly reduces postoperative opioid consumption.

Acetaminophen↗
PubMed2006

[Cardiopulmonary exercise testing in exercise-induced pulmonary hypertension].

OBJECTIVE: To determine the accuracy of cardiopulmonary exercise-testing (CPET) in detecting exercise-induced pulmonary hypertension. BACKGROUND: CPET plays a key role in the investigation of exertional breathlessness. Exercise-induced pulmonary hypertension has been recently demonstrated to be a cause of exertional dyspnea. However, the features of CPET associated with the condition are still unknown. METHODS: We prospectively studied CPET and exercise echo-cardiography characteristics in 39 patients complaining of exertional breathlessness. Patients could be divided into 3 groups as follows: 1) control subjects having normal pulmonary arterial pressure at rest [pulmonary arterial systolic pressure < 35 mmHg] and at peak exercise [pulmonary arterial systolic pressure < 45 mmHg]; 2) patients having exercise-induced PH; 3) patients having resting PH. Results from CPET have been analyzed within each group. RESULTS: Patients developing exercise-induced PH revealed an increased VD/VT ratio and CO2 gradient (P[a-ET]CO2) at peak exercise compared to controls (VD/VT at 0.38 +/- 0.1 vs 0.29 +/- 0.11 and P[a-ET]CO2 at 4,6 +/- 3,1 vs 1 +/- 3,8 mmHg). VD/VT and P[a-ET]CO2 were increased in patients with resting PH. A VD/VT ratio at peak exercise higher than 0.34 was 72.7% sensitive and 71% specific in predicting exercise-induced PH. Positive and negative predictive values were 72.7% and 70.1% respectively. CONCLUSION: Patients with exercise-induced PH did not decrease or may increase dead space during exercise. Therefore CPET may be a useful tool in selecting patients who need to undergo further exercise haemodynamic investigations.

Adaptation, Physiological↗
PubMed2006

Simplified stepwise management of primary spontaneous pneumothorax: a pilot study.

In primary spontaneous pneumothorax (PSP) requiring intervention, removal of air from the pleural space can be achieved by manual needle aspiration or by pleural drainage after insertion of a chest tube. This study aimed to evaluate the efficacy and safety of a serial-steps approach with a single system (small-calibre catheter/Heimlich valve) in a homogeneous population of patients with a first episode of PSP. All patients had an 8.5 F distally multiperforated polyurethane pigtail catheter inserted via the anterior route, at the bedside without any guidance, using the Seldinger technique. A one-way Heimlich valve was connected to the catheter, allowing the air to flow spontaneously outwards for 24-48 h. Thereafter, if the lung failed to re-expand wall suction was applied. Patients with an air leak persisting for >4 days were referred for surgery. Primary end-points were success rates at 24 h and 1 week, and 1 yr recurrence-free survival. In total, 41 consecutive patients entered the study. They were typically thin, young, smoking males. No procedure-related complications were observed. The need for pain relief medication was minimal. Within the first 24 h, most of the patients were able to walk around and half of them were able to take a shower with their catheter in place. The 24-h and 1-week success rates were 61 and 85%, respectively, and the actuarial 1-yr recurrence rate was 24%. Four patients underwent surgical pleurodesis because of a persistent air leak. The length of stay when excluding the four surgical cases was 2.3+/-1.3 days. When 24-h and 1-week success rates and recurrence at 12 months were taken as end-points, the method described here is as effective as simple manual needle aspiration or a conventional chest tube thoracotomy. These results support further studies assessing this "one system, serial-steps approach" in an outpatient management algorithm.

Adolescent↗
PubMed2005

Prediction of vesicoureteral reflux after a first febrile urinary tract infection in children: validation of a clinical decision rule.

AIMS: To test the reproducibility of a highly sensitive clinical decision rule proposed to predict vesicoureteral reflux (VUR) after a first febrile urinary tract infection in children. This rule combines clinical (family history of uropathology, male gender, young age), biological (raised C reactive protein), and radiological (urinary tract dilation on renal ultrasound) predictors in a score, and provides 100% sensitivity. METHODS: A retrospective hospital based cohort study included all children, 1 month to 4 years old, with a first febrile urinary tract infection. The sensitivities and specificities of the rule at the two previously proposed score thresholds (< or =0 and < or =5) to predict respectively, all-grade or grade > or =3 VUR, were calculated. RESULTS: A total of 149 children were included. VUR prevalence was 25%. The rule yielded 100% sensitivity and 3% specificity for all-grade VUR, and 93% sensitivity and 13% specificity for grade > or =3 VUR. Some methodological weaknesses explain this lack of reproducibility. CONCLUSIONS: The reproducibility of the previously proposed decision rule was poor and its potential contribution to clinical management of children with febrile urinary tract infection seems to be modest.

Child, Preschool↗
PubMed2005

[Measurement of daily physical activity in patients with cystic fibrosis].

BACKGROUND: Cystic fibrosis (CF) patients often have a good level of daily activity contrasting with the impairment of pulmonary functions. The aim of this prospective study was to measure physical daily activity (PDA) in CF-patients and compare it with rest pulmonary functions and exercise tolerance. MATERIAL AND METHODS: Fifteen CF-patients and 9 control subjects have been recruted. PDA was measured during 7 days using an accelerometer: Global-PDA (daily mean counts per day), percentage of inactivity (1 to 2 METS), light activity (2 to 3 METS), and moderate-to-hard activity (greater than 3 METS). Spirometry (FEV1, Vital Capacity) and clinical exercice testing (VO2, workload) were also performed. RESULTS: Global-PDA of CF-patients was lower than control subjects (p < 0.05). Light activity (15.5 +/- 3.3% vs 13.4 +/- 2.4%) and inactivity (81.2 +/- 9% vs 79.9 +/- 3.1%) were similar in both groups. Only moderate-to-hard activity was greater in control subjects than in CF-patients (6.7 +/- 1.6% vs 3.3 +/- 3.4%; p < 0.05). There were correlations between Global-PDA and moderate-to-hard activity (r = 0.94), FEV1 (r = 0.72), Vital Capacity (r = 0.77), workload peak (r = 0.88), and VO2peak (r = 0.70). CONCLUSION: CF-patients have a lower PDA than control subjects because of a lower moderate-to-hard activity (>3 METS). In clinical practice, interviewing a CF-patient on his "run-life" PDA (<3 METS) has poor relationship with his real "moderate-to-hard activity", and this is a confusing factor for clinicians.

Adult↗
PubMed2005

Invasive pulmonary aspergillosis in chronic obstructive pulmonary disease: an emerging fungal pathogen.

Acute invasive pulmonary aspergillosis occurs predominantly in immunocompromised hosts, with increasing numbers of cases of invasive aspergillosis among patients with chronic obstructive pulmonary disease (COPD) being reported. Among 13 cases of invasive aspergillosis diagnosed in COPD patients admitted to the intensive care unit with acute respiratory distress, the only risk factor for invasive fungal infection was corticosteroid treatment. Invasive aspergillosis should be suspected in COPD patients receiving steroid treatment who have extensive pulmonary infiltrates. Survival depends on rapid diagnosis and early appropriate treatment. A decrease or interruption of steroid treatment should be considered as part of the overall therapeutic strategy.

Aspergillosis↗
PubMed2004

[VENT: International study of bronchoscopic lung volume reduction as a palliative treatment for emphysema].

BACKGROUND: Therapeutic options for patients with severe emphysema remain limited. In selected patients, lung volume reduction surgery has been shown to improve pulmonary function, exercise capacity, quality of life and also survival. The technique of inserting one-way valves endoscopically into the airways supplying the most affected areas of lung provides the possibility of achieving similar results to surgery (i.e. volume reduction) in a less invasive way, which is also reversible, since the valves can be removed at any time. This technique has been shown to be safe. The aim of this study is to evaluate the efficacy of this technique compared to optimal medical therapy in patients with heterogeneous emphysema defined according to radiological criteria. METHODS: A prospective, international, multicentre (20 centres) randomised trial is underway to establish the efficacy and safety of endobronchial valve placement in this patient group. This study will enrol 270 patients and be analysed on an intention to treat basis. Patients are randomised either to valve insertion or optimal medical treatment alone in a ratio of 2 to 1. Follow up will be ensured for at least one year. EXPECTED RESULTS: The two principal outcome measures will be improvement at six months in FEV1 and in six minute walk distance. The safety of the technique will be evaluated over the same period. Details of the study are available online for patients and their physicians at www.euroemphysema.com.

Bronchoscopy↗
PubMed2004

Development of a multiplex PCR for the identification of Staphylococcus genus and four staphylococcal species isolated from food.

AIMS: To develop a multiplex PCR that allows the identification of bacteria belonging to the Staphylococcus genus and in particular to the species Staphylococcus xylosus, S. saprophyticus, S. epidermidis and S. aureus isolated from food manufacturing plants. METHODS AND RESULTS: Five primer pairs were used in the multiplex PCR, one specific to the Staphylococcus genus and four specific to S. xylosus, S. saprophyticus, S. epidermidis and S. aureus species. All the 31 Staphylococcus reference strains yielded a specific PCR product with the genus-specific primers. Staphylococcus xylosus, S. saprophyticus, S. epidermidis and S. aureus gave a specific PCR fragment with the corresponding species-specific primers. No amplification with the Kocuria, Macrococcus and Micrococcus strains was observed in our conditions. This multiplex PCR was performed on 30 strains of Gram-positive cocci isolated from different workshops and fermented sausages. Among them, 28 belonged to the Staphylococcus genus and 14 were identified to S. saprophyticus, four to S. xylosus, two to S. aureus and one to S. epidermidis. CONCLUSIONS: This multiplex PCR provided reliable and repeatable PCR results. It allowed the identification of a major part of the isolates, highlighting the predominance of the S. saprophyticus species in the workshops studied. SIGNIFICANCE AND IMPACT OF THE STUDY: This tool is a useful way to screen the strains isolated from foodstuff and food environment and to monitor these species during the food processing.

Bacterial Typing Techniques↗
PubMed2003

Patterns of cerebral inflammatory response in a rabbit model of intrauterine infection-mediated brain lesion.

Although the fetal inflammatory response syndrome seems crucial to the association between intrauterine infection and white matter disease in human preterm infants, the underlying mechanisms remain unclear. Using our previously described rabbit model of cerebral cell death in the white matter and hippocampus induced by intrauterine Escherichia coli infection, we investigated inflammatory and astroglial responses in placenta and brain tissues, in correlation with cell death distribution. Brains and placentas were studied 12, 24, or 48 h following intrauterine inoculation of E. coli or saline (groups G12, G24, and G48). Diffuse monocyte-macrophage infiltrates positive for inducible nitric oxide synthase (i-NOS) were significantly more marked in G24 and G48 placentas than in controls. In the G48 fetuses with both diffuse cell death and focal periventricular white matter cysts mimicking cystic periventricular leukomalacia, a strong rabbit macrophage and inducible nitric oxide synthase immunostaining was observed at the border of these cystic lesions. In contrast, in the fetuses with only diffuse and significant cell death, no inflammatory or astroglial responses were detected in the white matter or hippocampus. Cell death was accompanied by i-NOS immunostaining in the hippocampus but not the white matter. Hippocampal cells positive for i-NOS usually displayed a neuronal phenotype. In this model, focal white matter cysts are accompanied by a robust inflammatory response, and diffuse cell death, which may mimic the white matter and hippocampal damage seen in very and extremely pre-term infants, occur in the absence of a detectable brain inflammatory response.

Animals↗
PubMed2003

5HTTLPR polymorphism in schizophrenic patients: further support for association with violent suicide attempts.

Previous studies testing the functional polymorphism in the promoter of the serotonin-transporter gene (5HTTLPR) in various psychiatric conditions have suggested that the association could be with an intermediate phenotype, impulsivity and/or violence rather than with a diagnosis. Schizophrenia is associated with a high risk of suicide, especially in patients with high impulsivity. We examined whether this polymorphism could be associated with violent suicide and/or impulsivity in schizophrenic patients. We genotyped the 5HTTLPR polymorphism in 185 unrelated schizophrenic patients from a French Caucasian population. The genotype frequencies significantly differed between patients who made violent suicide attempts and both, those who attempted suicide with a non-violent method (P = 0.013) and those who never attempted suicide (P = 0.026). The genotypes containing the low activity "short" allele was significantly more frequent in violent suicide attempters (P = 0.007) than in non-violent suicide attempters. No evidence was found for an association either with schizophrenia itself, when compared to gender and ethnically matched controls (n = 159) or with impulsivity, assessed using Barratt's Impulsivity Scale. Although replication studies are warranted, these results in schizophrenia further support the hypothesis that 5HTTLPR polymorphism is a risk factor for violent suicidal behavior.

Adult↗
PubMed2003

[Intra-cavity aspergilloma complicating necrotising sarcoid granulomatosis].

INTRODUCTION: Necrotising sarcoid granulomatosis is a rare clinical entity, characterised by the development of nodular pulmonary opacities, the diagnosis if which is based on the identification of characteristic pathological lesions. CASE REPORT: A 44-years-old male smoker presented with cough and fever. With the exception of a few basal crepitations clinical examination was normal. The chest x-ray showed multiple areas of alveolar consolidation scattered throughout both lung fields, some of which were cavitated. The thoracic CT scan confirmed the presence of cavitating nodules and hilar and mediastinal lymphadenopathy. Samples for mycobacteria were negative. A search for anti-neutrophil cytoplasmic antibodies was negative. Fibreoptic bronchoscopy was normal but transbronchial biopsies revealed giant cells. Lung biopsies taken by video thoracoscopy showed non-caseating granulomata with areas of fibrinoid necrosis and perivascular infiltration with lymphocytes, histology characteristic of necrotising sarcoid granulomatosis. Resolution occurred without treatment. The parenchymal lesions regressed leaving residual cavities. Four years later, following an episode of haemoptysis, the patient was found to have a squamous cell carcinoma (T1N0M0) and aspergillomas in the pulmonary cavities. CONCLUSIONS: Our observation demonstrates that the cavities of necrotising sarcoid granulomatosis may be complicated by aspergillomas.

Adult↗