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Biomedical subjects

C Hennequin

Publications and source records attributed to C Hennequin.

At least 19 recordsLinked to original sources
PubMed2003

[Infections by Candida sp. in intensive care. Survey of French practices].

OBJECTIVE: The isolation of Candida sp in nosocomial infections is on the increase and over the past 10 years many guidelines for "good" practices and recommendations have been published on the modalities for the management of systemic candidiasis. The aim of this paper was to assess the habits in the intensive care units in this domain in France. METHOD: A transversal survey on the habits was conducted from March to May 2001, using a questionnaire mailed to 200 intensive care units. RESULTS: One hundred eighty questionnaires (surgical reanimation: 12%, medical: 18%, medico-surgical: 70%) out of 200 (92.5%) were returned. The indirect diagnostic examinations: serology, search for antigenemia and PCR (Polymerase Chain Reaction) were never used in 21, 35 and 65% of cases. The systematic search for colonisation (a mean of 4 areas sampled) was conducted in all the patients by 19% of the investigators, in some patients by 53%, and never by 28%. An antifungal treatment was prescribed: in the presence of a positive haemoculture alone, once out of twice if the sample had been taken from a central catheter and in 2 cases out of 3 when the sample was peripheral. It was prescribed 6 times out of 10 after isolation of Candida sp following surgery or on needle aspiration of an intra-abdominal abscess, varyingly in the case of cadiduria, isolation of a Candida sp in a broncho-pulmonary sample or in abdominal draining and positive culture of a catheter, depending on the intensity of the colonisation, the severity of the clinical picture and the presence of factors of risk for Candida infection. It is still prescribed empirically depending on the same elements and the absence of explanation for worsening. When faced with candidemia in a non-neutropenic patient, a central catheter is not changed in 18% of cases. Depending on the microbiology, fluconazole is prescribed in: the identification of yeast without further precision (78% of cases), Candida sp without further precision (86% of cases), Candida non albicans without further precision (57% of cases), C. albicans (93% of cases), Candida non albicans other than C. krusei and C. glabrata (62% of cases), C. glabrata (36% of cases) with an increase in dose in 1 out of 2 cases. In the presence of C. glabrata or C. krusei, amphotericin B is the choice in respectively 51 and 75% of cases. To adapt the treatment.

Adult↗
PubMed2003

[Endobronchial brachytherapy: technique and indications].

The endobronchial brachytherapy procedure involves the insertion of an afterloading catheter into bronchus in close proximity to an endoluminal lesion, and to perform limited irradiation sparing as much as possible normal health tissues. The catheter is inserted during a classical flexible bronchoscopy. Three types of indications have been discussed: (i) palliative treatment of lung carcinoma, with or without laser desobstruction: an improvement in respiratory symptoms was observed in 60 to 80% of the cases; (ii) curative treatment for localised endobronchial carcinomas, in previously irradiated patients, or in case of contraindication of surgery or external beam irradiation; local control rate range from 60 to 70% at 2 years; (iii) combination of external irradiation and brachytherapy in the first line treatment of lung cancers. Two randomised trials did not show any improvement in survival for this approach; however, they have included advanced diseases. In the opposite, this association seems very effective for early stage lung carcinomas. Two major complications were regularly reported, haemoptysis and radiation bronchitis. Predictive factors for these toxicities are actually better known: haemoptysis could be due to a progressive disease more often than to brachytherapy itself; technical factors (dose, volume, fractionation), however, could explain a number of radiation bronchitis, and their incidence could decrease in the future.

Brachytherapy↗
PubMed2002

Invasive infections due to Trichoderma species: report of 2 cases, findings of in vitro susceptibility testing, and review of the literature.

Trichoderma species are filamentous fungi that were previously considered to be culture contaminants. We report 2 well-documented cases of invasive Trichoderma infections, and we comprehensively review the literature on this topic. Trichoderma species are mainly responsible for continuous ambulatory peritoneal dialysis-associated peritonitis (7 cases) and invasive infections in immunocompromised patients (9 cases) with a hematologic malignancy or solid-organ transplant. Definitive diagnosis is difficult to achieve because of the lack of specific diagnosis tools. Species identification can benefit from a molecular approach. Trichoderma longibrachiatum is the most common species involved in these infections. Regardless of the type of infection, the prognosis was poor, with 8 deaths among 18 cases. This may be partially because of the resistance of these organisms to the majority of available antifungal agents, including amphotericin B. Trichoderma species now should be added to the growing list of emerging filamentous fungal pathogens.

Adult↗
PubMed2002

Comparison of aerobic standard medium with specific fungal medium for detecting fusarium spp in blood cultures.

In order to compare the performances of a specific fungal medium and a standard aerobic medium for detecting growth of Fusarium spp. in blood, simulated blood cultures were performed. For lower inocula (10(2) and 10(3) cfu/ml taken together), fungal growth was detected significantly earlier using the fungal medium. The mean difference in the time to detection between the two media was 22.33 h at 10(2) cfu/ml, with the maximum difference being achieved for Fusarium verticilloides at 37.05 h. These in vitro test results suggest fungal medium could be useful for obtaining more rapid blood culture results when evaluating patients at risk for invasive infection with Fusarium spp.

Bacterial Typing Techniques↗
PubMed2002

Aspergillus antigen and PCR assays in bone marrow transplanted children.

Screening for Aspergillus antigen and DNA has been introduced for the early diagnosis of invasive aspergillosis (IA) in adults, but data in children at risk are scarce. Seventeen 1-108 month-old children were screened for Aspergillus antigenaemia by a commercial assay before and after bone marrow transplantation (BMT). Seventy-one serum samples were examined retrospectively by a novel nested PCR assay. Results of both assays were correlated with clinical, radiological and microbiological findings used for the definition of invasive aspergillosis by the European Organisation for Research and Treatment of Cancer (EORTC). Three cases of probable or possible IA were defined, and in 14 children invasive aspergillosis was ruled out. In 10 children, Aspergillus antigen was detected in at least two consecutive serum samples, a microbiological EORTC criteria of IA. Specific DNA was detected in 8 antigen-positive and 2 antigen-negative sera. A positive predictive value of 20% was calculated for both assays. Hence, a high rate of positive results of antigen Elisa and PCR assays in BMT children are due to transient antigenaemia and fungaemia without clinical relevance. According to our data, prospective studies in well defined pediatric patients are urgently needed to determine the value of serial Aspergillus PCR assays for the early diagnosis of invasive aspergillosis in children at risk.

Antigens, Fungal↗
PubMed2002

Biological basis for chemo-radiotherapy interactions.

For over 10 years, chemo-radiotherapeutic combinations have been used to treat locally advanced epithelial tumours. The rationale for these combinations relies on spatial cooperation or interaction between modalities. Interactions may take place (i) at the molecular level, with altered DNA repair or modification of the lesions induced by drugs or radiation, (ii) at the cellular level, notably through cytokinetic cooperation arising from differential sensitivity of the various compartments of the cell cycle to the drug or radiation, and (iii) at the tissue level, including reoxygenation, increased drug uptake or inhibition of repopulation or angiogenesis. Some mechanisms underlying interaction of radiation with cis-diammino-platinum (II) (cis-Pt), 5-fluoro-2'-deoxyuridine (5-FU), taxanes and gemcitabine are described. It is shown how various mechanisms including cell synchronisation and reoxygenation concur to paclitaxel-induced radiosensitisation. In the future, specific targeting of tumours, for example, with the epidermal growth factor receptor (EGFR) or angiogenesis inhibitors, should be achieved in order to increase the therapeutic index.

Antineoplastic Agents↗
PubMed2002

[Post-prostatectomy radiotherapy: for which patients and when?].

Biochemical relapse after radical prostatectomy is not exceptional, ranging from 10 to 40% in the literature. To prevent this biochemical failure, adjuvant radiotherapy was proposed to patients with a high risk of relapse. No phase III trial has actually validated this attitude. Best indications for adjuvant irradiation seem to be patients with an extensive extracapsular extension or multiple positive margins. Historical comparisons seems to confer, in these case, a benefit in biochemical control for adjuvant irradiation versus observation. Others authors prefer immediate post-operative irradiation, a delayed treatment, when biochemical relapse has occurred. This attitude has spared some patients irradiation useless. This salvage irradiation lowered the PSA level in 40 to 70% of the cases, but long-term efficiency is obtained only in the case of a low value of the PSA before irradiation. Delayed radiotherapy is, therefore, justified only if a close follow-up is performed, with repeated dosage of PSA. Whatever the case, it is important to differentiate between local and distant relapse: patients with positive nodes at the time of surgery are most likely at risk of distant relapse. It seems that patients with seminal vesicles involvement are also at high risk for distant relapse, but this must be confirmed.

Adenocarcinoma↗
PubMed2001

Medullary gnathostomiasis in a white patient: use of immunodiagnosis and magnetic resonance imaging.

A 48-year-old French diplomat presented with a sensory-motor paraparesis of rapid onset, leading to paraplegia. Successive magnetic resonance image scans showed lesions of the thoracic spinal cord that were at different levels from one examination to the next. Specific anti-gnathostome antibodies were detected by means of enzyme-linked immunosorbent assay and Western blot test in both plasma and cerebrospinal fluid. Albendazole treatment prevented disease progression, but only partial regression of the neurologic symptoms was obtained.

Albendazole↗
PubMed2001

Impact on survival of surgery after concomitant chemoradiotherapy for locally advanced cancers of the esophagus.

BACKGROUND: To evaluate the results of chemoradiotherapy with or without surgery in locally-advanced esophageal carcinomas (T3 and/or nodal involvement). METHODS: One hundred twelve patients with locally-advanced carcinoma of the esophagus without histologically proven invasion of the tracheobronchial tree or distant visceral metastases were treated with concomitant chemoradiotherapy followed by re-evaluation; surgery was performed or chemoradiotherapy continued, based on tumor regression and the patient's general status. Chemoradiotherapy consisted of concomitant 5-fluorouracil (5FU)(1 g/m(2) day 1-3), cisplatinum (50 mg/m(2) day 1 and 2), and external beam irradiation up to a dose of 40 or 43.2 Gy. After a 4-week rest period, radical esophagectomy or a new cycle of chemoradiotherapy (up to a total dose of 65 Gy) was performed. RESULTS: A complete clinical response was obtained in 25.7% of the patients and a partial response in 45.9%. Fifty patients underwent surgery, but only 38 patients had an esophagectomy. Post-esophagectomy mortality was 5.3%. A complete histologic response rate of 23.7% was obtained. Two- and 5-year survival rates were, respectively, 41.5% and 28.6% for the whole population. According to multivariate analysis, prognostic factors for survival were Karnofsky index, esophagectomy, and response to chemoradiotherapy. Five-year survival for patients who experienced a partial response to radiation and chemotherapy was 49.1% for those who had surgery and 23.5% for those treated without surgery (p = 0.003). There was no obvious benefit for the small number of patients treated surgically after complete response to radiation and chemotherapy. Toxicity, essentially hematologic, was moderate. CONCLUSION: For locally-advanced esophageal carcinomas, esophagectomy, after concomitant chemoradiotherapy, could improve the survival rate, especially for patients who responded partially to the latter.

Adult↗
PubMed2001

Analysis of expression of GroEL (Hsp60) of Clostridium difficile in response to stress.

Our laboratory has previously shown that adherence of Clostridium difficile to tissue culture cells is augmented by various stresses and that GroEL, a heat shock protein, serves an adhesive function in this bacterium. In this communication, RT-PCR, SDS-PAGE and immunoblotting were used to study the stress response in C. difficile following heat, acid or osmotic shock, iron deprivation or presence of a subinhibitory concentration of ampicillin in the culture medium. All these stresses increased transcription of groEL and production of GroEL to various degrees. Furthermore, the protein was found in membrane fractions and in the extracellular space after heat stress.

Ampicillin↗
PubMed2001

[The role of the laboratory in the diagnosis and prevention of fungal infections].

Fungal infections account for an increasing fraction of nosocomial infections. The laboratory is essential to ascertain the diagnosis. Significant progress has been recently achieved in direct diagnostic tools (better sensitivity of direct examination, development of chromogenic identification media). Diagnostic sensitivity of blood cultures can be increased with the use of special fungal media for culture. However, indirect diagnostic methods remain unsatisfactory, even though some new data support the usefulness of simultaneous detection of circulating antigens and corresponding antibodies. In the future, the contribution of molecular biology techniques could be of great interest, either in the diagnostic (detection of fungal DNA in the serum) or in the identification of species. Last but not least, molecular typing allows a precise monitoring of fungal ecology that could prove useful to the understanding of the physiopathology of infections and to the anticipation and prevention of epidemic outbreaks.

Clinical Laboratory Techniques↗
PubMed2001

GroEL (Hsp60) of Clostridium difficile is involved in cell adherence.

Previous results have demonstrated that adherence of Clostridium difficile to tissue culture cells is augmented by various stresses; this study focussed on whether the GroEL heat shock protein is implicated in this process. The 1940 bp groESL operon of C. difficile was isolated by PCR. The 1623 bp groEL gene is highly conserved between various C. difficile isolates as determined by RFLP-PCR and DNA sequencing, and the operon is present in one copy on the bacterial chromosome. The 58 kDa GroEL protein was expressed in Escherichia coli in fusion with glutathione S:-transferase and the fusion protein was purified from IPTG-induced bacterial lysates by affinity chromatography on glutathione-Sepharose. A polyclonal, monospecific antiserum was obtained for GroEL which established by immunoelectron microscopy, indirect immunofluorescence and immunoblot analysis that GroEL is released extracellularly after heat shock and can be surface associated. Cell fractionation experiments suggest that GroEL is predominantly cytoplasmic and membrane bound. GroEL-specific antibodies as well as the purified protein partially inhibited C. difficile cell attachment and expression of the protein was induced by cell contact, suggesting a role for GroEL in cell adherence.

Amino Acid Sequence↗
PubMed2001

Sputum itraconazole concentrations in cystic fibrosis patients.

Itraconazole diffusion in sputum was studied in 11 cystic fibrosis patients with allergic bronchopulmonary aspergillosis. There was a high interindividual variability in sputum itraconazole concentration and sputum/serum drug concentration ratio. Three children had sputum drug concentrations before oral administration that were lower than the itraconazole MIC at which 90% of Aspergillus fumigatus strains were inhibited, although their serum drug concentrations were within the therapeutic range.

Adolescent↗
PubMed2001

Characterization of a cell surface protein of Clostridium difficile with adhesive properties.

Our laboratory has previously shown that Clostridium difficile adherence to cultured cells is enhanced after heat shock at 60 degrees C and that it is mediated by a proteinaceous surface component. The present study was undertaken to identify the surface molecules of this bacterium that could play a role in its adherence to the intestine. The cwp66 gene, encoding a cell surface-associated protein of C. difficile 79-685, was isolated by immunoscreening of a C. difficile gene library with polyclonal antibodies against C. difficile heated at 60 degrees C. The Cwp66 protein (66 kDa) contains two domains, each carrying three imperfect repeats and one presenting homologies to the autolysin CwlB of Bacillus subtilis. A survey of 36 strains of C. difficile representing 11 serogroups showed that the 3' portion of the cwp66 gene is variable; this was confirmed by sequencing of cwp66 from another strain, C-253. Two recombinant protein fragments corresponding to the two domains of Cwp66 were expressed in fusion with glutathione S-transferase in Escherichia coli and purified by affinity chromatography using gluthatione-Sepharose 4B. Antibodies raised against the two domains recognized Cwp66 in bacterial surface extracts. By immunoelectron microscopy, the C-terminal domain was found to be cell surface exposed. When used as inhibitors in cell binding studies, the antibodies and protein fragments partially inhibited adherence of C. difficile to cultured cells, confirming that Cwp66 is an adhesin, the first to be identified in clostridia.

Adhesins, Bacterial↗
PubMed2001

Microsatellite typing as a new tool for identification of Saccharomyces cerevisiae strains.

Since Saccharomyces cerevisiae appears to be an emerging pathogen, there is a need for a valuable molecular marker able to distinguish among strains. In this work, we investigated the potential value of microsatellite length polymorphism with a panel of 91 isolates, including 41 clinical isolates, 14 laboratory strains, and 28 strains with industrial relevance. Testing seven polymorphic regions (five trinucleotide repeats and two dinucleotide repeats) in a subgroup of 58 unrelated strains identified a total of 69 alleles (6 to 13 per locus) giving 52 different patterns with a discriminatory power of 99.03%. We found a cluster of clinical isolates sharing their genotype with a bakery strain, suggesting a digestive colonization following ingestion of this strain with diet. With the exception of this cluster of isolates and isolates collected from the same patient or from patients treated with Saccharomyces boulardii, all clinical isolates gave different and unique patterns. The genotypes are stable, and the method is reproducible. The possibility to make the method portable is of great interest for further studies using this technique. This work shows the possibility to readily identify S. boulardii (a strain increasingly isolated from invasive infections) using a unique and specific microsatellite allele.

Bronchoalveolar Lavage Fluid↗