Biomedical subjects

B Joly

Publications and source records attributed to B Joly.

At least 19 recordsLinked to original sources

PubMed2004

[Caustic burns. Clinical study of 24 patients with sulfuric acid burns in Cambodia].

Over a period of 12 years, 24 burns have been treated by a Cambodgian and French team (Doctors of the World). This experience has revealed some characteristics of this population: (1) a majority of young women (2/3), (2) victims of assault (20 cases). These notions are found in the medical literature particularly South East Asia. All cases are of a third degree. Every surgeon, every anesthetist should apply emergency measures which are recalled here. The aims is to close all the burns surface through a skin graft within a month. However the patients are treated 6 months to 2 years after the burn and have, at this stage, terrible sequella (22 patients). Treating them requires the coordinated efforts of a multidisciplinary specialized team. The challenge is to save the eyes, the mouth, the nose and give back a "human" face to these young burns who are often rejected because of their handicap. Enabling them to smile again is a strong commitment from the surgeon and from the patient who has to undergo multiple operations and a long treatment over the years.

Adolescent↗

PubMed2003

Children's bicycle helmet use and injuries in Hillsborough County, Florida before and after helmet legislation.

The purpose of this research was to explore the changes in children's bicycle helmet use and motor vehicle bicycle related injuries in Hillsborough County, Florida before and after passage of the Florida's bicycle helmet law for children under the age of 16. The results show a significant increase in bicycle helmet use among children, ages 5-13, in the post-law years compared with the pre-law years. Also, there has been a significant decline in the rates of bicycle related motor vehicle injuries among children in the post-law years compared with the pre-law years. Although there have been complementary educational and outreach activities in the county to support helmet use, it appears that the greatest increase in use occurred after the passage of the helmet law. It is recommended that educational efforts continue to sustain helmet use rates and decreases in injuries.

Accidents, Traffic↗

PubMed2001

Identification of human enterovirulent Escherichia coli strains by multiplex PCR.

Some strains of Escherichia coli are involved in enteric infections in both adults and children. However the classical diagnostic methods can not differentiate pathogenic from nonpathogenic E. coli, because of the lack of phenotypic differences. In this study, we developed multiplex PCR in order to amplify fragments of specific virulence genes of the five main E. coli pathotypes. Fragments of the expected size were obtained using previously or newly designed primers and allowed identification of 10 virulence genes in only 5 reactions. This method was applied to the detection of pathogenic E. coli isolated from 90 patients' stools specimens during an 18-month survey. Patients were suffering from diarrhea or hemolytic uremic syndrome and in 13 cases (14.4%), an enterovirulent E. coli strain was detected. This diagnostic method could therefore represent an important technique in clinical laboratories which lack standard tests for these pathogens.

Adolescent↗

PubMed2001

Probiotic activities of Lactobacillus casei rhamnosus: in vitro adherence to intestinal cells and antimicrobial properties.

The interest of probiotics as remedies for a broad number of gastrointestinal and other infectious diseases has gained wide interest over the last few years, but little is known about their underlying mechanism of action. In this study, the probiotic activities of a human isolate of Lactobacillus casei subsp. rhamnosus strain (Lcr35) were investigated. Using intestinal Caco-2 cell line in an in vitro model, we demonstrated that this strain exhibited adhesive properties. The inhibitory effects of Lcr35 organisms on the adherence of three pathogens, enteropathogenic Escherichia coli (EPEC), enterotoxigenic E. coli (ETEC) and Klebsiella pneumoniae, were determined. A decrease in the number of adhering pathogens was observed, using either preincubation, postincubation or coincubation of the pathogens with Lcr35. Moreover, the antibacterial activities of cell-free Lcr35 supernatant was examined against nine human pathogenic bacteria, ETEC, EPEC, K. pneumoniae, Shigella flexneri, Salmonella typhimurium, Enterobacter cloacae, Pseudomonas aeruginosa, Enterococcus faecalis and Clostridium difficile. The growth of all strains was inhibited, as measured by determining the number of viable bacteria over time, but no bactericidal activity was detected in this in vitro assay. Together, these findings suggest that this probiotic strain could be used to prevent colonization of the gastrointestinal tract by a large variety of pathogens.

Antibiosis↗

PubMed2001

Genetically related Escherichia coli strains associated with Crohn's disease.

Escherichia coli strains isolated from patients with Crohn's disease (CD) with chronic ileal lesions (n=14), early endoscopic recurrent lesions (n=20), without endoscopic recurrence (n=7), and controls (n=21) were compared by ribotyping. The dendrogram generated by 50 ribotype profile analysis revealed a large cluster of genetically linked E coli strains isolated significantly more frequently from patients with chronic and recurrent CD (24/33 patients) than from controls (9/21) (p<0.05). Most patients operated on for chronic ileal lesions (78.5%) harboured E coli strains belonging to cluster A (p<0.002 v controls). The prevalence of patients with early recurrent lesions harbouring E coli strains belonging to this cluster was high but not significant, although 16 strains isolated from eight patients presented the same ribotype profile. In this cluster, 21 of 26 strains isolated from patients with active CD demonstrated adherent ability to differentiated Caco-2 cells, indicating that most of the genetically related strains share a common virulence trait. Comparison of E coli strains recovered from ulcerated and healthy mucosa of patients operated on for CD demonstrated in each patient that a single strain colonised the intestinal mucosa. Our results suggest that although a single E coli isolate was not found in Crohn's ileal mucosa, some genotypes were more likely than others to be associated with chronic or early recurrent ileal lesions.

Bacterial Adhesion↗

PubMed2001

[Associations of patients and tissue banks].

Research dealing with tissue is more important to day than ever. Techniques of molecular genetics have indeed permitted the identification of a large number of new proteins that have now to be localised in the tissue and in the cell, in health and disease. This step has to be made in order to elaborate the adequate animal models in which new therapeutics can be tested. In France, however, human tissue samples have become difficult to obtain. Many factors contributed to this situation. Autopsies are now exceptionally performed. Doctors feel confident in their diagnosis and express rarely the need to control it. Families are opposed to post mortem more strongly than before, especially when the reasons for performing it can not be explained before the death of the patient. French law now makes the explicit consent of the patient mandatory before any research. This practically limits all post mortem investigations to those that had been planned before death. The possibility of giving tissue post mortem to allow research has to be publicised, particularly by associations of patients. The organisation that should manage to collect and store the samples at a large scale and over the whole country is lacking. Its structure is still discussed: should it be supported by the state itself, by private funding, possibly by the associations of patients themselves? Patients Associations are ready to play a crucial role: they realised that the present system was inefficient, they are presently trying to organise tissue banks; they will finally have to explain to their members why they should care for research, how they could help and how they will have to accept the absence of immediate spectacular results.

France↗

PubMed2000

[Verotoxin-producing Escherichia coli infections: study of its prevalence in children in the Auvergne region].

Verotoxin producing Escherichia coli (VTEC) have been associated with disease outbreaks of diarrhea hemorrhagic colitis and hemolytic-uremic syndrome in humans. Contamination occurs mainly by ingestion of beef and dairy products, but water and person to person transmission have also been described. Most of the clinical signs are due to the production of Stx1 and/or Stx2 Shiga toxins, also called verotoxins. Other virulence factors include enterohemolysin, and the product of the eae gene, intimin, involved in the attaching and effacing adherence phenotype. The predominant serotype is O157:H7, but VTEC strains of more than one hundred serotypes can cause human disease. In order to determine the prevalence of VTEC infections among children in the central part of France, stool samples from hospitalized children were examined for stx1 and stx2 genes by using a polymerase chain reaction (PCR) technique. From October 1997 to September 1998, 658 stool samples were analysed: among them 19 (3%) were stx-PCR positive. Only 8 children out of 19 had diarrhea, and for 5 of them, an enteric pathogen other than VTEC was isolated. VTEC strains were isolated from 10 samples: most of the isolates did not produce verotoxins at a high level, and they did not belong to serotypes associated with pathogenicity, which might explain the absence of relationship between VTEC isolation and pathogenicity in our study.

Adolescent↗

PubMed2000

Helium-oxygen breathing in the early emergency care of acute severe asthma: a randomized pilot study.

The aim of this study was to establish whether a clinical trial, comparing helium-oxygen (HeO2) breathing to standard therapy, would be feasible during the out-of-hospital care of adult patients with severe asthma. Although the primary outcome in a definitive trial will be a decrease in morbidity, the present study primarily examined: (1) if the strategy could be successfully implemented in emergency ambulatory units; (2) if the research staff could enroll enough patients, given the resources. Nine patients were included in the conventional treatment group, and seven patients in the HeO2 group. Patients randomized to the HeO2 group breathed the mixture for a 12-hour period. Clinical and biological parameters improved for all patients. There was no trend towards a HeO2 benefit, whether during the initial out-of-hospital nor the ICU care. No patient was intubated within the study period. HeO2 breathing was considered to be simple to initiate, and no side effects were reported. In conclusion, while HeO2 breathing is easy to apply, even in the out-of-hospital setting, the few enrolled patients did not appear to benefit from this treatment. Regarding our low inclusion rate and the lack of positive effect trend, we believe that a large definitive trial will be difficult to initiate in such an emergency care setting.

Acute Disease↗

PubMed2000

Prevalence and characterization of Shiga toxin-producing Escherichia coli isolated from cattle, food, and children during a one-year prospective study in France.

During a 1-year survey of Shiga toxin-producing Escherichia coli (STEC) prevalence in central France, 2,143 samples were investigated by PCR for Shiga toxin-encoding genes. A total of 330 (70%) of 471 fecal samples collected from healthy cattle at the Clermont-Ferrand slaughterhouse, 47 (11%) of 411 beef samples, 60 (10%) of 603 cheese samples, and 19 (3%) of 658 stool specimens from hospitalized children with and without diarrhea were positive for the stx gene(s). A STEC strain was isolated from 34% (162 of 471) of bovine feces, 4% (16 of 411) of beef samples, 1% (5 of 603) of cheese samples, and 1.5% (10 of 658) of stool specimens. Of the 220 STEC strains isolated, 34 (15%) harbored the stx(1) gene, 116 (53%) harbored the stx(2) gene, and 70 (32%) carried both the stx(1) and stx(2) genes. However, 32 (14.5%) were not cytotoxic for Vero cells. The eae gene, found in 12 (5%) of the 220 strains, was significantly associated with the stx(1) gene and with isolates from children. Sequences homologous to ehxA were found in 102 (46%) of the 220 strains. Thirteen serotypes, OX3:H2, O113:H21, O113:H4, OX3:H21, O6:H10, OX178:H19, O171:H2, O46:H38, O172:H21, O22:H16, O91:H10, O91:H21, and O22:H8, accounted for 102 (55%) of 186 typeable isolates, and only one strain (0.5% of the 186 STEC isolates from cattle), belonged to the O157:H7 serotype. We showed that the majority of the STEC isolates from cattle, beef, and cheese were not likely to be pathogenic for humans and that the STEC strains isolated from children in this study were probably not responsible for diarrheal disease. Finally, the strains associated with hemolytic-uremic syndrome in the same geographical area were shown to belong to particular subsets of the STEC population found in the bovine reservoir.

Abattoirs↗

PubMed1999

Characterization of enteroaggregative Escherichia coli isolates.

Forty enteraggregative Escherichia coli (EAggEC) previously characterized by their ability to adhere to HEp-2 cells or/and their hybridization with the 1-kb EAggEC DNA probe were investigated for the presence of adherence factors and heat-stable enterotoxin (EAST1)-encoding genes. Only 45% of the isolates harbored the EAST1-encoding genes as detected by polymerase chain reaction. None of them hybridized with an AAF/II-encoding gene specific DNA probe and 35% (14/40) were positive in a PCR assay using primers specific for aggC, an accessory gene of the AAF/I-encoding operon. Cloning and sequence analysis of the aggA variant from one isolate, EAggEC 457, revealed 68.9% identity between its deduced amino acid sequence and those of the aggA product from the AAF/I-producing reference strain, E. coli 17.2. No major protein subunit was detected at the surface of EAggEC 457 compared to the bacterial surface extract of E. coli 17.2.

Adhesins, Escherichia coli↗

PubMed1999

Oral administration of a glutamine-enriched diet before or after endotoxin challenge in aged rats has limited effects.

Numerous studies indicate beneficial effects of glutamine (Gln) in many models of catabolic adult rats. No data were available for aged rats. The effects of oral L-Gln-enriched diet were tested in endotoxemic 24-mo old rats. First, rats received for 7 d (from d0 to d7) an oral diet supplemented with either L-Gln [1g/(kg. d)] or casein (Cas: isonitrogenous supply) prior to lipopolysaccharide (LPS) challenge. The rats were then killed after 24 h food deprivation (from d7 to d8). Endotoxemia induced a catabolic response as shown by muscle glutamine depletion, hyperphenylalaninemia, small bowel atrophy and impaired functionality and bacterial translocation. The Gln-enriched diet did not prevent muscle Gln depletion but significantly (P </= 0.05) enhanced plantaris protein content by 18% compared to the Cas-LPS rats and reduced the plasma phenylalanine-to-tyrosine ratio (1.32 +/- 0.05 vs. 1.54 +/- 0.10, respectively, P </= 0.01). Gut translocation and histomorphology were unaffected by diet. However, Gln pretreatment reduced the fall in sucrase and glucoamylase activities in the ileum, respectively, by 55 and 63% vs. Cas supplementation (P </= 0.05). In a second study, after endotoxin challenge, healthy 24-mo-old rats were then food-deprived for 2 d (from d0 to d2), received a nonpurified diet for 4 d (from d2 to d6), and then Cas or L-Gln-supplemented diet for 7 d (from d6 to d13). No beneficial effects of Gln supplementation were observed except an increase of 50 and 56% in sucrase and glucoamylase activities in the ileum of Gln-treated rats, (P </= 0.01 vs. healthy rats). In conclusion, the effects of L-Gln supplementation in aged endotoxemic rats were limited.

Aging↗

PubMed1999

Consequences of reduction of Klebsiella pneumoniae capsule expression on interactions of this bacterium with epithelial cells.

Most Klebsiella pneumoniae clinical isolates are fully encapsulated and adhere in vitro to intestinal cell lines with an aggregative pattern. In this study, the influence of the capsule on interactions with epithelial cells was investigated by creating an isogenic mutant defective in the synthesis of the capsule. Determination of the uronic acid content of bacterial extracts confirmed that the mutant did not produce capsular polysaccharides whereas, with the wild-type strain, the level of encapsulation was growth phase dependent and reached a maximum during the lag and early log phases. Assays performed with different epithelial cell lines, Int-407, A-549, and HEp-2, showed that the capsule-defective mutant demonstrated greater adhesion than did the wild-type strain and that the aggregative pattern was maintained, indicating that the capsule was not related to the adhesion phenotype. In contrast, when the mucus-producing HT-29-MTX cells were used, the encapsulated wild-type strain adhered more strongly than did the capsule-defective mutant. No invasion properties were observed with any of the capsular phenotypes or cell lines used. The K. pneumoniae adhesin CF29K was detected by Western blot analysis and enzyme-linked immunosorbent assay on the surface of transconjugants obtained after transfer of a conjugative plasmid harboring the CF29K-encoding genes into both the wild-type and the capsule-defective strains. The amounts of adhesin detected were greater in the capsule-defective background strain than in the wild-type encapsulated strain and were associated with an increase in the level of adhesion to Caco-2 cells. Moreover, RNA slot blot experiments showed that transcription of the adhesin-encoding gene was markedly increased in the capsule-defective mutant compared to the wild-type encapsulated background. These results suggest (i) that the capsule plays an active role during the initial steps of the pathogenesis by interacting with mucus-producing cells but is subsequently not required for the adhesin-related interaction with the epithelial cell surface and (ii) that the expression of the adhesin is modulated by the presence of a capsule at a transcriptional level.

Bacterial Adhesion↗

PubMed1999

Invasive ability of an Escherichia coli strain isolated from the ileal mucosa of a patient with Crohn's disease.

Crohn's disease (CD) is an inflammatory bowel disease in which Escherichia coli strains have been suspected of being involved. We demonstrated previously that ileal lesions of CD are colonized by E. coli strains able to adhere to intestinal Caco-2 cells but devoid of the virulence genes so far described in the pathogenic E. coli strains involved in gastrointestinal infections. In the present study we compared the invasive ability of one of these strains isolated from an ileal biopsy of a patient with CD, strain LF82, with that of reference enteroinvasive (EIEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enteraggregative (EAggEC), enterohemorrhagic (EHEC), and diffusely adhering (DAEC) E. coli strains. Gentamicin protection assays showed that E. coli LF82 was able to efficiently invade HEp-2 cells. Its invasive level was not significantly different from that of EIEC and EPEC strains (P > 0.5) but significantly higher than that of ETEC (P < 0.03), EHEC (P < 0. 005), EAggEC (P < 0.004) and DAEC (P < 0.02) strains. Strain LF82 also demonstrated efficient ability to invade intestinal epithelial cultured Caco-2, Intestine-407, and HCT-8 cells. Electron microscopy examination of infected HEp-2 cells revealed the presence of numerous intracellular bacteria located in vacuoles or free in the host cell cytoplasm. In addition, the interaction of strain LF82 with epithelial cells was associated with the elongation of microvillar extensions that extruded from the host cell membranes and engulfed the bacteria. This internalization mechanism strongly resembles Salmonella- or Shigella-induced macropinocytosis. The use of cytochalasin D and colchicine showed that the uptake of strain LF82 by HEp-2 cells was mediated by both an actin microfilament-dependent mechanism and microtubule involvement. In addition, strain LF82 survived for at least 24 h in HEp-2 and Intestine-407 cells and efficiently replicated intracellularly in HEp-2 cells. PCR and hybridization experiments did not reveal the presence of any of the genetic determinants encoding EIEC, EPEC, or ETEC proteins involved in bacterial invasion. Thus, these findings show that LF82, which colonized the ileal mucosa of a patient with CD, is a true invasive E. coli strain and suggest the existence of a new potentially pathogenic group of E. coli, which we propose be designated adherent-invasive E. coli.

Adhesins, Bacterial↗

PubMed1998

Presence of adherent Escherichia coli strains in ileal mucosa of patients with Crohn's disease.

BACKGROUND & AIMS: Infectious agents are suspected of being involved in the pathogenesis of Crohn's disease. This study was designed to look for the presence of virulent Escherichia coli strains associated with the ileal mucosa of patients with Crohn's disease. METHODS: E. coli strains were recovered from resected chronic ileal lesions (n = 20), neoterminal ileum after surgery from patients with (n = 19) and without (n = 11) endoscopic recurrence, and controls (n = 13). Bacterial adhesion was determined in vitro using intestinal cell lines; other associated virulence factors were assessed by DNA hybridization and polymerase chain reaction experiments. RESULTS: None of the strains harbored any of the virulence factor-encoding genes of E. coli involved in acute enteric diseases. However, mannose-resistant adhesion to differentiated Caco-2 cells was found for 84.6% and 78.9% of the E. coli strains isolated from chronic and early recurrent lesions, respectively, compared with 33% of controls (P < 0.02). In addition, 21.8% of the strains induced a cytolytic effect by synthesis of an alpha-hemolysin. CONCLUSIONS: E. coli strains isolated from the ileal mucosa of patients with Crohn's disease adhere to differentiated intestinal cells and may disrupt the intestinal barrier by synthesizing an alpha-hemolysin.

Adult↗

PubMed1998

Inhibitory effect of roxithromycin on adhesion of Klebsiella pneumoniae strains 3051, CF504 and LM21.

The effect of subinhibitory concentrations of roxithromycin on the adhesion of three strains of Klebsiella pneumoniae to Int-407 cells was studied. Adherence was markedly inhibited and the effect was increased when roxithromycin was added to the cell culture medium rather than to the bacterial growth medium. Several assays were performed in order to understand the mechanism by which roxithromycin exerted this inhibitory effect. The greatest effect was obtained when roxithromycin was concentrated in the extracellular compartment; when roxithromycin was concentrated in the intracellular compartment, the inhibitory effect was reduced. The analysis of adhesion factors of bacteria showed that exposure to roxithromycin did not alter their apparent structure or quantity. Roxithromycin appears to interfere in the interaction between bacteria and eukaryotic receptors.

Anti-Bacterial Agents↗

PubMed1998

Non-O157:H7 Stx2-producing Escherichia coli strains associated with sporadic cases of hemolytic-uremic syndrome in adults.

From August 1996 to May 1997, six verotoxin-producing Escherichia coli (VTEC) strains were isolated from stool specimens of adults suffering from hemolytic-uremic syndrome (HUS). All the isolates were stx2 positive and belonged to different serotypes: O6:H4, O91:H10, O91:H21, O rough:H16, OX3:H-, and O nontypeable: H-. The enterohemolysin (Ehly)-encoding genes were detected in two isolates, and none of the isolates harbors the intimin (Eae)-encoding gene. These findings suggest that stx2-positive non-O157:H7 VTEC is a major cause of HUS in adults and that several sources of pathogens are responsible for local endemic infections.

Adhesins, Bacterial↗

PubMed1998

[Efficacy of an ultraviolet device for the disinfection of radiology cassettes].

The antimicrobial efficiency of a disinfection box of radiology cassettes, by means of a device which emits ultraviolet rays, was studied according to a method defined by the laboratory. Germ-carriers contaminated with Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans were irradiated and compared to non irradiated reference ones. The bactericidal and fungicidal efficiency was better than 99.9% in 5 minutes of irradiation. This procedure represents an interesting alternative to the chemical treatment of radiology cassettes.

Candida albicans↗

PubMed1997

Long-term maintenance of drug-metabolizing enzyme activities in rat hepatocytes after cryopreservation.

Recent studies have demonstrated that freshly isolated adult hepatocytes from various species can be hypothermically preserved for a short period or cryopreserved for a prolonged period before seeding in primary culture. This study was designed to determine whether rat hepatocytes could be maintained functional for a prolonged period after either hypothermic preservation or cryopreservation. Cold storage was carried out in University of Wisconsin solution (UW) and freezing in Leibovitz medium added with 10% fetal calf serum and 16% dimethyl sulfoxide. Rat hepatocytes were then set up either in pure conventional culture or in coculture with rat liver epithelial cells. Various functions were measured over 4- and 15-day periods, i.e., albumin secretion rate, deethylation of ethoxyresorufin and phenacetin, dealkylation of pentoxyresorufin, glucuronidation and sulfoconjugation of paracetamol, and N-acetylation of procainamide. No major differences were observed between unfrozen, frozen, and UW-preserved cells. While in pure culture all the functions tested were markedly decreased after 3 or 4 days, they remained high over the 15-day period in coculture, being either maintained or increased after 7-12 days compared to initial values. These results clearly demonstrate that when maintained under suitable culture conditions, rat hepatocytes can fully recover after hypothermic preservation or cryopreservation and therefore represent a suitable in vitro model system for pharmacotoxicological studies.

Acetaminophen↗