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Biomedical subjects

D Mathieu

Publications and source records attributed to D Mathieu.

At least 19 recordsLinked to original sources

[Massive haemoptysis associated with pulmonary Strongyloides stercoralis hyperinfestation].

INTRODUCTION: Pulmonary infestation with Strongyloides stercoralis is an exceptionally rare cause of haemoptysis, the diagnosis being difficult and often delayed. CASE REPORT: We report the case of a retired coal miner suffering from pneumoconiosis who presented with acute respiratory insufficiency and massive haemoptysis, with a fatal outcome, associated with pulmonary stongyloidosis. The only identified source of infestation with Strongyloides stercoralis was his period in the coal mine and the only risk factors for the hyperinfestation were a short course of systemic corticosteroid therapy and the presence of a peritoneal-auricular valve. CONCLUSION: This observation illustrates the importance of a systematic search for anguillosis in ex coal miners prior to any immunosuppressant treatment in order to avoid the serious and frequently fatal form of hyperinfestation with Strongyloides stercoralis.

Aged↗

Thirty-day mortality of nosocomial systemic bacterial infections according to antibiotic susceptibility in an 800-bed teaching hospital in France.

Overall 30-day mortality among patients with nosocomial bacterial infections was analysed according to antibiotic susceptibility in an 800-bed hospital. Survival analysis identified three factors associated with an increased mortality rate: (1) a longer interval between admission and onset of infection; (2) bacterial resistance; and (3) the severity of the initial illness in the intensive care unit. The increased mortality rate associated with antibiotic resistance was observed for all bacterial species with the exception of Gram-positive cocci, and remained significant or near-significant regardless of the hospital ward.

Anti-Bacterial Agents↗

Determination of glyphosate in biological fluids by 1H and 31P NMR spectroscopy.

Identification of glyphosate in four cases of poisoning, using nuclear magnetic resonance spectroscopy of biological fluids is reported. It has been performed by using a combination of 1H and 31P NMR analyses. Characterization of the N-(phosphonomethyl) glycine herbicide was achieved by chemical shift considerations and coupling constant patterns: CH2-(P) presents specific resonance at 3.12 ppm and appears as a doublet with a H-P characteristic coupling constant of 12.3 Hz. Moreover, resonances due to isopropylamine were present, confirming the ingestion of the considered trade formulation. After a calibration step, quantitation was performed by 1H and 31P NMR spectroscopy. The benefit and reliability of NMR investigations of biological fluids are discussed, particularly when the clinical picture is quite confusing.

Adult↗

Fatal streptococcal necrotizing fasciitis as a complication of axillary brachial plexus block.

A 74-yr-old diabetic woman developed necrotizing fasciitis of the right upper limb after axillary brachial plexus block for carpal tunnel decompression. Clinical signs included oedema, diffuse swelling and bullae; rapidly followed by toxic shock syndrome and multiorgan failure. The patient died 48 h after hospital admission, despite broad-spectrum antibiotics, surgical treatment and supportive measures for the management of shock and multiorgan failure. Cultures yielded group A Streptococcus. Delay in antibiotic and surgical treatment probably affected the outcome. Early diagnosis and treatment are essential to improve the outcome of streptococcal necrotizing fasciitis.

Aged↗

[Epidemiology and antimicrobial resistance of Streptococcus pneumoniae strains isolated in Ile de France area during 2001].

OBJECTIVE: The authors wanted to assess the level of Streptococcus pneumoniae antibiotic resistance in Ile de France. METHOD: In 2001, 637 clinical strains of S. pneumoniae were prospectively collected from 32 microbiology laboratories. RESULTS: Fifty one percent of strains were isolated from children under 15 years of age and 49% from adults. In children, 76% of strains came from otitis media, 20% from blood culture, in adults most strains (92%) came from blood culture. The overall prevalence of non-susceptible penicillin pneumococci was 61% higher in children (73%) than in adults (50%). Among the non-susceptible penicillin pneumococci 21.8% were resistant (CMI > 1 mg/l). Strains with decreased susceptibility to amoxicillin and cefotaxime were 38% and 17% respectively. Resistant strains to these two drugs (CMI > 2 mg/l) were rare 2.6% and 0.4% respectively. Among other antimicrobial agents, rate of resistance was 63% to erythromycin, 47% to cotrimoxazole, 40% to tetracycline, and 23% to chloramphenicol. The most frequent serogroups were serogroups 19 and 14, respectively 23% and 18%. Serotypes included in heptavalent vaccine covered 90% of children strains under 2 years of age. CONCLUSIONS: The prevalence of resistance to penicillin was high in children particularly in otitis media pus (76%).

Adult↗

Influence of the textile structure on the degradation of explanted aortic endoprostheses.

OBJECTIVES: To investigate mechanisms of textile failure in explanted human aortic endoprostheses. MATERIALS AND METHODS: Endoprostheses (n31) underwent optical and scanning electron microscopy, filament dynamometry, and saturation index measurement. RESULTS: The macroscopic lesions observed in the Stentor and Vanguard devices were holes at the extremities of the stents and slipping of the warp yarns at the level of sutures or of the longitudinal seams. The macroscopic lesions observed in AneurX endoprostheses were holes, slipping of the warp yarns and ruptures of the ligatures. The macroscopic lesions observed in the two Talent endoprostheses were sections of fibers at the level of the suture holes and few areas lesions of wear, with sometimes holes at the contact of the stent extremities. Stentor, Vanguard and AneurX all demonstrated low saturation indexes of the fabric (44-59%) with an important anisotropy. Whereas the Talent endograft demonstrated a high index of saturation (124-131%) with a low anisotropy. We did not demonstrate significant polymer degradation in any of the endoprostheses. CONCLUSIONS: It is essential to take into account the saturation index to optimally choose a woven textile for the construction of an endoprosthesis since this property of the textile may contribute to explain the macroscopic lesions observed. We did not observe significant polymer degradation by filament dynamometry but further studies are needed to confirm these data.

Aortic Aneurysm, Abdominal↗

Evaluation of the automated phoenix system for potential routine use in the clinical microbiology laboratory.

A comparative study was designed to evaluate the identification (ID) and antimicrobial susceptibility testing (AST) performances of the BD Phoenix Automated Microbiology System (Becton Dickinson Diagnostic Systems [BD], Pont de Claix, France). A total of 305 single clinical isolates were collected, and comparisons were made with routine manual methods in use in our microbiology laboratories. The percentages of correct IDs were 93.3, 89.4, 91.8, and 85.7% for enterobacteria, nonfermenting gram-negative bacilli, staphylococci, and streptococci-enterococci, respectively. The median ID time was 3 h, and the median time for AST was 10 h 30 min. AST results showed variable percentages of errors for the different antibiotics. None of the enterobacteria and 0.3% of Pseudomonas aeruginosa isolates showed a very major error (VME). Only one strain of Staphylococcus aureus showed a VME with oxacillin. We demonstrate here the efficiency of the Phoenix system, which can be used for the majority of strains encountered in a university-based laboratory, for ID and AST.

Anti-Bacterial Agents↗

[Early and late nosocomial broncho-pulmonary diseases in intensive care. Comparative study of risk factors and of causing bacteria].

OBJECTIVES: Determine the risk factors and germs responsible for early-onset (E) and late-onset (L) nosocomial broncho-pulmonary infections (NBPI), in order to improve preventive strategies and the choice of initial antibiotherapy. METHODS: An observational prospective study conducted in an intensive care unit of 30 beds, from March 1993 to September 1999. The patients presenting with an ENBPI and those with an LNBPI were compared with patients without NBPI using univariate and then multivariate analysis. RESULTS: 517 (14%) of early-onset NBPI were diagnosed, but the majority of NBPI were late-onset (87%). Multiresistant bacteria predominated. The similarity in the germs responsible for the early and late onset forms of NBPI was probably related to the large number of patients transferred from other departments (82%) and having already received antibiotics before their admission to the intensive care unit (49%). Multivariate analysis identified anti-ulcer and long term corticosteroid treatments as common risk factors for early and late onset forms of NBPI, digestive failure, tracheotomy and kidney failure as risk factors for ENBPI and the number of antibiotics used in intensive care and the duration of mechanical ventilation as factors of risk for LNBPI. CONCLUSION: The limited use of antibiotics and anti-ulcer agents could improve the prevention of early and late onset forms of NBPI. The distinction in intensive care between the two forms of NBPI must be emphasized by the notion of prior hospitalization.

Anti-Bacterial Agents↗

Mechanisms of rupture of knitted polyester vascular prostheses: an in vitro analysis of virgin prostheses.

OBJECTIVES: Previous explant retrieval studies have shown ruptures occurring on the remeshing line and the guide line of two types of warp-knitted grafts. The aim of our study was to characterize the mechanisms these ruptures. MATERIALS AND METHODS: We performed an in vitro study of the mechanical and chemical characteristics of virgin prostheses. We studied 2 virgin polyester warp-knitted grafts models: the Cooley Double Velour and the Microvel Double Velour constructed by Meadox (USA), using the following techniques: characterization and de-knitting of the textile structure, circumferential tensile strength, filament dynamometry, critical dissolution time of the filaments and scanning electron microscopy. RESULTS: Both prostheses were constructed in the same way but the texturized yarns of the Cooley graft included twice as many filaments (54) than the Microvel (27). There was more adsorbed tension in the Cooley structure than in the Microvel. The circumferential tensile strength test demonstrated that the Cooley graft always ruptured on the remeshing line and the Microvel graft always ruptured at the interface between the remeshing line and the standard line. Filament dynamometry demonstrated a heterogeneous behavior of the filaments inside the yarns, mainly at the remeshing line of the Cooley graft (27.1 cN/tex +/- 11.5% versus 26.1 cN/tex +/- 2.2% for the guide line and 28 cN/tex +/- 6.7% for the standard knit). Critical dissolution time of the filaments was significantly lower for the Microvel grafts (2.5 sec versus 17.2 sec for the Cooley). CONCLUSIONS: Rupture of knitted polyester prostheses are probably an underestimated phenomenon. They may occur at specific areas of the graft. Further studies are required to determine whether all grafts of this type are at risk.

Blood Vessel Prosthesis↗

Detection of oxidative stress. Interest of GC-MS for malondialdehyde and formaldehyde monitoring.

Ischemia-reperfusion syndrome is a condition where the role of oxygen free radicals is important. Malondialdehyde (MDA) and formaldehyde (FA), products of lipid peroxidation, are the presumptive markers for the development of oxidative stress in tissues and plasmas. A GC-MS method for the determination of MDA and FA in rat brain extract is described. Rat brains were homogenized with deionized water. The homogenates were derivatized with 2,4-dinitrophenylhydrazone (DNPH) to obtain hydrazines derivatives of MDA and FA. The hydrazine derivatives were analyzed by GC-MS and quantitation was by single ion monitoring (SIM). The retention times of FA and MDA were, respectively, 13.75 and 14.20 min, and for SIM quantitation, ion at m/z 210 for FA, and m/z 158 for MDA were used. The results showed that it is possible to estimate the products of lipid peroxidation in brain and to monitor the oxidative stress developed during the ischemia-reperfusion syndrome compared to the normal values.

Animals↗

Focal nodular hyperplasia of the liver in men: is presentation the same in men and women?

BACKGROUND: Focal nodular hyperplasia (FNH) of the liver is a benign hepatic lesion relatively common in women. No studies specifically designed to describe the presentation and imaging findings in males have been published. AIMS: The aims of this study were: (a) to describe the clinical and imaging findings in 18 men with FNH, and (b) to compare these data with those observed in 216 women with FNH observed during the same nine year period. PATIENTS AND METHODS: According to a final diagnosis of FNH assessed either by pathological examination or by magnetic resonance (MR), the medical charts of 18 men with FNH observed at our institution were reviewed. In order to compare clinical and MR presentations, the files of 216 women with a total of 291 FNH lesions, investigated during the same nine year period, were reviewed. RESULTS: Eighteen FNH lesions, with a mean diameter of 37.5 mm, were demonstrated in the 18 male patients. A total of 291 lesions with a mean diameter of 63.4 mm were comparatively demonstrated in 216 female patients. Mean age at diagnosis was significantly higher in men (p<0.01) and mean FNH size was significantly smaller in men (p<0.001). Surgery was more frequently performed in men (72.2%) than in women (16.7%) (p<0.001). CONCLUSIONS: Our data indicate that FNH is rare in men and that the lesions are smaller and more often atypical than those in women.

Abdominal Pain↗

Nosocomial tracheobronchitis in mechanically ventilated patients: incidence, aetiology and outcome.

The aim of this study was to determine the incidence, the organisms responsible for and the impact on outcome of nosocomial tracheobronchitis (NTB) in the intensive care unit (ICU). This prospective observational cohort study was conducted in a 30-bed medical/surgical ICU over a period of 6.5 yrs. All patients ventilated for >48 h were eligible. Patients with nosocomial pneumonia (NP) without prior NTB were excluded. Patients with first episodes of NTB were compared with those without NTB by univariate analysis. The study diagnosed 201 (10.6%) cases of NTB. Pseudomonas aeruginosa was the most common bacteria. NP rates were similar in patients with NTB compared with patients without NTB. Even in the absence of subsequent NP, NTB was associated with a significantly higher length of ICU stay and duration of mechanical ventilation in both surgical and medical populations. Mortality rates were similar in NTB patients without subsequent NP compared with patients without NTB. Antimicrobial treatment in NTB patients was associated with a trend to a better outcome. Nosocomial tracheobronchitis is common in mechanically ventilated intensive care unit patients. In this population, nosocomial tracheobronchitis was associated with longer durations of intensive care unit stay and mechanical ventilation. Further studies are needed to determine the impact of antibiotics on outcomes of patients with nosocomial tracheobronchitis.

Aged↗

Separation and quantification of paraquat and diquat in serum and urine by capillary electrophoresis.

The use of capillary electrophoresis (CE) for simultaneous qualitative and quantitative detection of paraquat (PQ) and diquat (DQ) in both serum and urine was investigated. The two herbicides were extracted from biological fluids with liquefied phenol. Serum required a deproteinization with chloroform and ammonium sulfate as pretreatment. The extracts were hydrodynamically injected and the complete separation was carried out in 10 min, using a capillary tube (75 microm i.d., 500 mm) of fused silica containing 50 mM phosphate buffer (pH 2.50) as the carrier. UV absorbance detection at 200 nm was performed by an on-column detector. The analytes were characterized by their respective migration times. Analytical recoveries were 52.6% for PQ and 62.6% for DQ in serum, and 71.4% and 59.3%, respectively, in urine. The linearity was studied up to 4 mg/L and the limits of detection (LODs) were better than 5 pg/mL in serum or urine. The CE method described was applied to the characterization of two lethal poisonings and results were related.

Adult↗

Physico-chemical requirements for cellular uptake of pAntp peptide. Role of lipid-binding affinity.

The pAntp peptide, corresponding to the third helix of the Antennapedia homeodomain, is internalized by a receptor-independent process into eucaryotic cells. The precise mechanism of entry remains unclear but the interaction between the phospholipids of plasma membrane and pAntp is probably involved in the translocation process. In order to define the role of peptide-lipid interaction in this mechanism and the physico-chemical properties that are necessary for an efficient cellular uptake, we have carried out an Ala-Scan mapping. The peptides were labeled with a fluorescent group (7-nitrobenz-2-oxo-1,3-diazol-4-yl-; NBD) and their cell association was measured by flow cytometry. Furthermore, we determined the fraction of internalized peptide by using a dithionite treatment. Comparison between cell association and cell uptake suggests that the affinity of pAntp for the plasma membrane is required for the import process. To further investigate which are the physico-chemical requirements for phospholipid-binding of pAntp, we have determined the surface partition coefficient of peptides by titrating them with phospholipid vesicles having different compositions. In addition, we estimated by circular dichroism the conformation adopted by these peptides in a membrane-mimetic environment. We show that the phospholipid binding of pAntp depends on its helical amphipathicity, especially when the negative surface charge density of phospholipid vesicles is low. The cell uptake of pAntp, related to lipid-binding affinity, requires a minimal hydrophobicity and net charge. As pAntp does not seem to translocate through an artificial phospholipid bilayer, this might indicate that it could interact with other cell surface components or enters into cells by a nonelucidated biological mechanism.

Alanine↗

Pulsed field gel electrophoresis typing of coagulase-negative staphylococci with decreased susceptibility to teicoplanin isolated from an intensive care unit.

Increased isolation of coagulase-negative staphylococci (CoNS) with decreased susceptibility to teicoplanin prompted this epidemiological survey in the authors intensive care unit. Of 224 medical and surgical patients with hepatobiliary disease, in hospital between December 1998 and July 1999, 14 (6.3%) had at least one isolate of CoNS with decreased susceptibility to teicoplanin. A total of 27 isolates with decreased susceptibility to teicoplanin were recovered from these 14 patients. Pulsed field electrophoresis (PFGE) with Sma I endonuclease demonstrated that CoNS isolates obtained from different patients were unrelated. In addition, different isolates obtain from the same patient were also unrelated, with the exception of two patients. Eighteen out of 27 isolates (66.7%) with decreased susceptibility to teicoplanin were recovered after an earlier treatment with teicoplanin or vancomycin (median 13.1 g, range 2.4-32.7 g per patient). Only four CoNS strains with decreased susceptibility to teicoplanin induced serious infection, all of which responded well to vancomycin therapy. Emergence of CoNS strains with decreased susceptibility to teicoplanin remained limited in hospitalized patients, and was not related to a clonal spread of a particular resistant strain.

Adult↗

Flumazenil use in an emergency department: a survey.

OBJECTIVE: To evaluate the efficacy of flumazenil use by a one-year survey of practice in tan emergency department. DESIGN: During a one-year period, an observational prospective study in the emergency department of an urban community hospital enrolled every patient admitted with a history of pure or mixed benzodiazepine acute poisoning. Case records were secondarily reviewed by an expert group. Actual flumazenil use during hospitalization was compared to currently recommended indications. In order to evaluate the efficacy of flumazenil use, patients who received flumazenil were matched with those who did not and effects on mortality, morbidity, number of costly procedures (CT scan, diagnostic toxicology, etc.) and duration of hospital stay were determined. RESULTS: Of the 1529 patients admitted in 1 year for acute poisoning, 478 reportedly ingested at least one benzodiazepine. Twenty-nine patients (6%) received flumazenil in the emergency department whereas the expert reviewers recommended flumazenil use in only 18 (3.7%). In 11/29 (38%) cases, the use of fumazenil was considered inappropriate. The expert group considered flumazenil to be contraindicated in 93 of 478 patients. Nonetheless, flumazenil was used in 11 patients (rate of potentially harmful flumazenil use: 11/93; 12%), and a severe complication occurred in one of these patients after flumazenil. No significant difference could be shown in outcome, complication rate, number of complex procedures or duration of hospital stay between patients who received flumazenil and matched patients who did not. CONCLUSION: The use of flumazenil in the clinical practice of an emergency department fails to show any beneficial effect in adult patients. Moreover, contraindications are frequently overlooked and this may expose patients to substantial risk of complications.

Adolescent↗

Doxorubicin-peptide conjugates overcome multidrug resistance.

A well-known mechanism leading to the emergence of multidrug-resistant tumor cells is the overexpression of P-glycoprotein (P-gp), which is capable of lowering intracellular drug concentrations. To overcome this problem, we tested the capability of two peptide vectors that are able to cross cellular membranes to deliver doxorubicin in P-gp-expressing cells. The antitumor effect of peptide-conjugated doxorubicin was tested in human erythroleukemic (K562/ ADR) resistant cells. The conjugate showed potent dose-dependent inhibition of cell growth against K562/ADR cells as compared with doxorubicin alone. Doxorubicin exhibited IC50 concentrations of 65 microM in the resistant cells, whereas vectorized doxorubicin was more effective with IC50 concentrations of 3 microM. After treatment of the resistant cells with verapamil, the intracellular levels of doxorubicin were markedly increased and consequent cytotoxicity was improved. In contrast, treatment of resistant cells with verapamil did not cause any further enhancement in the cell uptake nor in the cytotoxic effect of the conjugated doxorubicin, indicating that the conjugate bypasses the P-gp. Finally, we show by the in situ brain perfusion method in P-gp-deficient and competent mice that vectorized doxorubicin bypasses the P-gp present at the luminal site of the blood-brain barrier. These results indicate that vectorization of doxorubicin with peptide vectors is effective in overcoming multidrug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗