Biomedical subjects

Christelle Basset

Publications and source records attributed to Christelle Basset.

8 recordsLinked to original sources

PubMed2005

Bactericidal and anti-adhesive properties of culinary and medicinal plants against Helicobacter pylori.

AIM: To investigate the bactericidal and anti-adhesive properties of 25 plants against Helicobacter pylori (H. pylori). METHODS: Twenty-five plants were boiled in water to produce aqueous extracts that simulate the effect of cooking. The bactericidal activity of the extracts was assessed by a standard kill-curve with seven strains of H. pylori. The anti-adhesive property was assessed by the inhibition of binding of four strains of FITC-labeled H. pylori to stomach sections. RESULTS: Of all the plants tested, eight plants, including Bengal quince, nightshade, garlic, dill, black pepper, coriander, fenugreek and black tea, were found to have no bactericidal effect on any of the isolates. Columbo weed, long pepper, parsley, tarragon, nutmeg, yellow-berried nightshade, threadstem carpetweed, sage and cinnamon had bactericidal activities against H. pylori, but total inhibition of growth was not achieved in this study. Among the plants that killed H. pylori, turmeric was the most efficient, followed by cumin, ginger, chilli, borage, black caraway, oregano and liquorice. Moreover, extracts of turmeric, borage and parsley were able to inhibit the adhesion of H. pylori strains to the stomach sections. CONCLUSION: Several plants that were tested in our study had bactericidal and/or anti-adhesive effects on H. pylori. Ingestion of the plants with anti-adhesive properties could therefore provide a potent alternative therapy for H. pylori infection, which overcomes the problem of resistance associated with current antibiotic treatment.

Anti-Bacterial Agents↗

PubMed2005

Hepatic environment elicits monocyte differentiation into a dendritic cell subset directing Th2 response.

BACKGROUND/AIMS: Dendritic cells (DCs), which play a critical role during immune response, could present alternative differentiation patterns depending on tissue microenvironment. Our aim was to examine the influence of hepatic microenvironment on human monocyte differentiation into DCs. METHODS: Cytology, immunophenotyping, cytokine production and T-cell activation were analyzed in DCs differentiated from human monocytes co-cultured with rat liver epithelial cells (RLEC) or human cells from various tissue origins and compared to control DCs obtained on plastic with GM-CSF/IL-4. RESULTS: RLEC environment promotes DC differentiation in the presence of IL-4 without GM-CSF. These DCs evidence similar expression of MHC-II, co-stimulatory and adhesion molecules than control DCs, but distinct lineage markers defining a CD11c+/CD14+/CD123+ DC subset. This phenotype is common to DCs from RLEC and human liver environment and differs from that obtained with skin or intestine environments. Functionally, they produce IL-10 but not IL-12p70 and favor IL-4/IL-10 secretion by T-cells rather than IFN-gamma. CONCLUSIONS: Our results confirm that tissue niches modulate DC differentiation and demonstrate that hepatic environment influences monocyte differentiation into a DC subset directing Th2 response, a key data for understanding the specialized immune response in liver. They also make RLEC co-culture system useful for studying liver DC functions.

Animals↗

PubMed2005

Comparison of image analysis software packages in the assessment of adhesion of microorganisms to mucosal epithelium using confocal laser scanning microscopy.

We have compared current image analysis software packages in order to find the most useful one for assessing microbial adhesion and inhibition of adhesion to tissue sections. We have used organisms of different sizes, the bacterium Helicobacter pylori and the yeast Candida albicans. Adhesion of FITC-labelled H. pylori and C. albicans was assessed by confocal microscopy. Four different Image analysis software packages, NIH-Image, IP Lab, Image Pro+, and Metamorph, were compared for their ability to quantify adhesion of the two organisms and several quantification methods were devised for each package. For both organisms, the dynamic range that could be detected by the software packages was 1x10(6)-1x10(9) cells/ml. Of the four software packages tested, our results showed that Metamorph software, using our 'Region of Interest' method, with the software's 'Standard Area Method' of counting, was the most suitable for quantifying adhesion of both organisms because of its unique ability to separate clumps of microbial cells. Moreover, fewer steps were required. By pre-incubating H. pylori with the glycoconjugate Lewis b-HSA, an inhibition of binding of 48.8% was achieved using 250 mug/ml Lewis b-HSA. The method we have devised using Metamorph software, provides a simple, quick and accurate way of quantifying adhesion and inhibition of adhesion of microbial cells to the epithelial surface of tissue sections. The method can be applied to organisms ranging in size from small bacteria to larger yeast cells.

Animals↗

PubMed2004

Are Helicobacter species and enterotoxigenic Bacteroides fragilis involved in inflammatory bowel disease?

The aim of this study was to determine if either Helicobacter or enterotoxigenic Bacteroidesfragilis (ETBF) was linked to inflammatory bowel disease (IBD), using PCR. We analyzed the luminal washings and colonic biopsies of 35 patients with IBD and 37 control patients. The presence of Helicobacter was confirmed in the luminal washing of one IBD patient and three control patients and in the biopsies of two IBD patients. Ten of 28 control patients and 8 of 32 IBD patients had a positive luminal washing for the enterotoxin gene. Six of 33 control patients and 4 of 32 IBD patients had positive biopsies. The prevalence of the enterotoxin gene was higher in IBD patients with active disease compared with patients with inactive disease, although it did not achieve statistical significance. In conclusion, Helicobacter was not associated with IBD in our population of patients, although ETBF may be associated with active disease.

Adult↗

PubMed2004

Helicobacter pylori: current status and future prospects.

Helicobacter pylori is a global pathogen that causes severe gastrointestinal diseases leading to a significant morbidity and mortality. There is an effective treatment for peptic ulcer disease, however, this is being compromised by an increase in the prevalence of antibiotic resistance. Although alternative rescue regimens have been advocated, the best strategy would be to prevent disease, especially in the case of gastric cancer for which there is still no treatment. One approach is to inhibit the first step in the pathogenic process - adhesion of the organism to the host tissue. Another and probably a better approach is vaccination, but clinical trials have so far been unsuccessful. There is still a large uncertainty in relation to how H. pylori causes disease. Knowledge from genomics, proteomics, and the relationship between polymorphism of the bacterium and the host, as well as the continuing investigation of the role played by important virulence factors in the outcome of the disease, will help both in understanding pathogenesis of disease and in the design of the best vaccine.

Animals↗

PubMed2003

Innate immunity and pathogen-host interaction.

The skin and contiguous mucosal surfaces define the primary locus of interaction between host and micro-organisms. In this review, we focus on the innate immune system in the mucosa, which manages to deal with invading pathogens, the mechanisms that organisms have evolved in order to circumvent this primary defensive barrier and, finally, potential therapeutic manipulation of the innate immune system that was the focus of meeting at a Euroconference/Workshop on "Novel Strategies of Mucosal Immunisation through Exploitation of Mechanisms of Innate Immunity in Pathogen-Host Interaction", which was held in Siena, Italy, November 2002.

Animals↗

PubMed2002

Inflammatory bowel disease: is the intestine a Trojan horse?

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory condition of the intestines that is clinically heterogenous. The cause(s) of IBD are currently unknown but the mechanisms of injury are immunological. Increasingly there is an emphasis on the study of the complex interactions at the interface of self and non-self--the gastrointestinal epithelial surface--in relationship to the pathogenesis of disease. There is mounting evidence that a lack of tolerance to the normal commensal flora of the intestine may underlie the disease pathogenesis. Several genetic loci that are markers of disease susceptibility have been identified. These loci map to areas of the genome that are concerned with antigen presentation or cytokine secretion and suggest a genetic heterogeneity that underlies the clinical differences. Overall a picture is emerging of defects in epithelial barrier function and, or immunoregulation leading to immune responses that are triggered or exaggerated by the antigenic components of the normal flora.

Epithelium↗

PubMed2002

Helicobacter: a paradigm shift in peptic ulcer disease and more?

There are many diseases where the cause is unknown and this makes a specific treatment difficult. In many cases all that can be achieved is amelioration of the illness. Peptic ulcer disease was one such condition no more that 20 years ago. The management was drastic--either an operation or life-long medication in order to reduce the acid secreted by the stomach. However, the cause of this condition was discovered in 1983. Although initially sceptical, the medical fraternity now almost universally endorse Helicobacter pylori as the cause of the majority of stomach ulcers. Peptic ulcers can now be cured by antibiotics. This is a major shift in medical practice. Continued investigations on Helicobacter pylori are bringing to light other possible associations with disease as well as delineating plausible biological mechanisms for disease pathogenesis.

Autoantibodies↗