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Biomedical subjects

A Leclercq

Publications and source records attributed to A Leclercq.

At least 19 recordsLinked to original sources
PubMed2006

Quantum-chemical investigation of second-order nonlinear optical chromophores: comparison of strong nitrile-based acceptor end groups and role of auxiliary donors and acceptors.

We report a detailed quantum-chemical investigation of donor-acceptor substituted dipolar nonlinear optical chromophores incorporating the 4-(dimethylamino)phenyl donor end group and a variety of strong heterocyclic acceptor end groups, including tricyanofurans and tricyanopyrroles. In particular, we study the variation of the molecular second-order polarizability (beta) with the acceptor end group and when inserting auxiliary donors (thiophene) and acceptors (thiazole) into the pi bridge. Both finite-field calculations (in the context of local contributions) and sum-over-states calculations were carried out in order to probe the relationship between beta and the chemical structure of the various chromophores. The trends obtained with these two methods are fully consistent. The large beta values (up to 700 x 10(-30) esu) as well as the observed tunability of the optical absorption maximum (lambda(max)) make the chromophores investigated here interesting candidates for use in electro-optic applications at telecommunications wavelengths.

Journal Article↗
PubMed2004

Atypical colonial morphology and low recoveries of Listeria monocytogenes strains on Oxford, PALCAM, Rapid'L.mono and ALOA solid media.

The performance of four commercial media, polymyxin-acriflavine-LiCl-ceftazidime-aesculin-mannitol (PALCAM), Oxford, Rapid'L.mono (Bio-Rad, Marne la Coquette, France) and Agar Listeria according to Ottaviani and Agosti (ALOA: AES Laboratoire, Combourg, France; Biolife, Milan, Italy), used to detect and enumerate 176 Belgian strains of Listeria monocytogenes of human and food origin, was evaluated. Four strains showed a low recovery and/or atypical colonies on one or more media. These results showed that a combination of these media, especially alternative media (Rapid'L.mono and/or ALOA) with esculin-containing media (PALCAM and/or Oxford), should therefore be recommended to detect or enumerate atypical strains of L. monocytogenes. In outbreak case investigation for example, incubation of plates should be extended to at least 96 h if no colonies are typical or growth does not appear after 48 h. This is a cost/benefit calculation that should be done in the context of recent listeriosis risk assessments.

Cheese↗
PubMed2002

Comparison of fecal coliform agar and violet red bile lactose agar for fecal coliform enumeration in foods.

A 24-h direct plating method for fecal coliform enumeration with a resuscitation step (preincubation for 2 h at 37 +/- 1 degrees C and transfer to 44 +/- 1 degrees C for 22 h) using fecal coliform agar (FCA) was compared with the 24-h standardized violet red bile lactose agar (VRBL) method. FCA and VRBL have equivalent specificities and sensitivities, except for lactose-positive non-fecal coliforms such as Hafnia alvei, which could form typical colonies on FCA and VRBL. Recovery of cold-stressed Escherichia coli in mashed potatoes on FCA was about 1 log unit lower than that with VRBL. When the FCA method was compared with standard VRBL for enumeration of fecal coliforms, based on counting carried out on 170 different food samples, results were not significantly different (P > 0.05). Based on 203 typical identified colonies selected as found on VRBL and FCA, the latter medium appears to allow the enumeration of more true fecal coliforms and has higher performance in certain ways (specificity, sensitivity, and negative and positive predictive values) than VRBL. Most colonies clearly identified on both media were E. coli and H. alvei, a non-fecal coliform. Therefore, the replacement of fecal coliform enumeration by E. coli enumeration to estimate food sanitary quality should be recommended.

Agar↗
PubMed2001

Particular biochemical profiles for enterohemorrhagic Escherichia coli O157:H7 isolates on the ID 32E system.

The ability of the ID 32E system to identify and discriminate 74 Escherichia coli O157 isolates among 106 E. coli non-O157 isolates was evaluated. The results showed atypical biochemical reactions but accurate identification at the species level and no unique biochemical profile numbers for E. coli O157, although these numbers were distinct from those of other serotypes.

Bacterial Typing Techniques↗
PubMed2001

Hazard analysis of Escherichia coli O157:H7 contamination during beef slaughtering in Calvados, France.

To identify hazard points and critical points during beef slaughtering, which is a necessary first step toward developing a hazard analysis and critical control point system to control meat contamination by Escherichia coli O157:H7, samples (n = 192) from surfaces, work tops, worker's hands, and beef carcasses were collected from a slaughterhouse in Calvados, France. Five strains of E. coli O157:H7 were isolated from a footbridge and a worker's apron at the preevisceration post and from a worker's hand at the defatting post. Three isolates carried stx2c, eae, and EHEC-hlyA genes and showed similar molecular types by random amplified polymorphic DNA, polymerase chain reaction IS3, and XbaI pulsed-field gel electrophoresis. Thus, this study has shown that preevisceration and defatting post and associated worker's materials are critical points for carcasses contamination by E. coli O157:H7 during beef slaughtering.

Abattoirs↗
PubMed2000

High homogeneity of the Yersinia pestis fatty acid composition.

The cellular fatty acid compositions of 29 strains of Yersinia pestis representing the global diversity of this species have been analyzed by gas-liquid chromatography to investigate the extent of fatty acid polymorphism in this microorganism. After culture standardization, all Y. pestis strains studied displayed some major fatty acids, namely, the 12:0, 14:0, 3-OH-14:0, 16:0, 16:1omega9cis, 17:0-cyc, and 18:1omega9trans compounds. The fatty acid composition of the various isolates studied was extremely homogeneous (average Bousfield's coefficient, 0.94) and the subtle variations observed did not correlate with epidemiological and genetic characteristics of the strains. Y. pestis major fatty acid compounds were analogous to those found in other Yersinia species. However, when the ratios for the 12:0/16:0 and 14:0/16:0 fatty acids were plotted together, the genus Yersinia could be separated into three clusters corresponding to (i) nonpathogenic strains and species of Yersinia, (ii) pathogenic Yersinia enterocolitica isolates, and (iii) Yersinia pseudotuberculosis and Y. pestis strains. The grouping of the two latter species into the same cluster was also demonstrated by their high Bousfield's coefficients (average, 0.89). Therefore, our results indicate that the fatty acid composition of Y. pestis is highly homogeneous and very close to that of Y. pseudotuberculosis.

Animals↗
PubMed1998

Interferon therapy in LKM-1 positive patients with chronic hepatitis C: follow-up by a quantitative radioligand assay for CYP2D6 antibody detection.

BACKGROUND/AIMS: Liver/kidney microsomal type 1 (LKM-1) antibodies described by indirect immunofluorescence using frozen sections of kidney, stomach and rat liver define a group of patients with type 2 autoimmune hepatitis. Sera react with a non-glycosylated 50-kD protein of the endoplasmic reticulum, which was recently identified as cytochrome P4502D6 (CYP2D6). LKM-1 antibodies may also be associated with hepatitis C virus infection (HCV+/LKM-1+). For this subset of patients, the choice of steroids or interferon alpha therapy may be difficult because of the association of hepatitis C virus infection and autoimmune manifestations. Recently we developed a quantitative immunoprecipitation radioligand assay using 35S-methionine-labeled CYP2D6 protein produced by in vitro transcription and translation reaction. This method detects antibodies against linear and conformational epitopes in both AIH-2 and HCV+/LKM-1+ patients. The aim of this study was to analyze the time-course of HCV+/LKM-1+ patients, applying our radioligand assay over a long follow-up. METHODS: We studied five patients who were positive for CYP2D6 antibodies from among 235 chronic hepatitis C virus hepatitis patients (2.1%) treated with interferon alpha for a minimal follow-up of 2 years. We analyzed LKM-1 antibody titer sequentially by radioligand assay, HCV RNA titer and alanine aminotransferase activity in these patients. RESULTS: We found no aggravation of liver disease in this group of patients. Three of these patients showed a sustained biochemical and virological response after interferon. Two others responded partially to interferon therapy. Alanine aminotransferase levels and HCV-RNA decreased during interferon therapy in responder patients. CYP2D6 antibodies did not change in three responder patients during follow-up. One responder patient decreased CYP2D6 antibody level by radioligand assay, but indirect immunofluorescence titers showed a similar pattern. One partial responder patient decreased CYP2D6 antibody level but was negative by indirect immunofluorescence. CONCLUSIONS: Our results show that patients with hepatitis C virus who are positive for CYP2D6 antibodies may be treated with interferon, and respond in the same way as CYP2D6 antibody negative patients. Radioligand assay could be helpful for monitoring HCV+/LKM-1+ patients receiving interferon therapy.

Adult↗
PubMed1998

[Gardner syndrome. Maxillofacial management of an extremely advanced form].

Gardner's syndrome is a very rare hereditary disease resulting from an embryo genesis disorder involving all three ectodermal, mesodermal and endodermal layers. Generally non-digestive tract signs disclose the syndrome. Underlying silent digestive anomalies should be investigated. Endodermal anomalies may have a fundamental effect on prognosis. Manifestations in our case were severe, with ectodermal and mesodermal anomalies occurring late. Maxillofacial management was required because of the critical esthetic and functional implications.

Adult↗
PubMed1995

The MUC5AC gene: RFLP analysis with the Jer58 probe.

We have recently obtained evidence that the locus corresponding to three groups of partial tracheobronchial cDNAs (A = Jer47, B = Jer57, C = Jer58) which mapped to chromosome 11p15 and was given the symbol MUC5 corresponds to two distinct genes which we have provisionally called MUC5B and MUC5AC. Here we describe the detection, using the Jer58 probe, which contains a 24-bp tandem repeat, of polymorphism in the MUC5AC gene with seven different restriction enzymes.

Bronchi↗
PubMed1994

[Functional and occupational repercussions and seeking care services in chronic asthma].

This article reports on a 5-month long prospective survey carried out in 1990 on 208 patients aged 18 and over, suffering from moderate to severe asthma. The recorded data included information on the history of the illness, the respiratory problems encountered and asthma attacks, the repercussions the illness had on household and professional occupations, the perceived state of health, drug consumption and recourse to external services. The medical costs and production loss due to this pathology were also estimated.

Activities of Daily Living↗
PubMed1991

[Surgical treatment of pyloric stenosis of ulcerous origin. Apropos of 68 cases].

The study turns about 68 cases of post ulcerous pyloric stenosis operated from 1970 to 1990, that means 8.5% of the duodenal ulcers (796 cases) operated during this period. The stenosis was entire or strangled in 27 cases (39.7%) with an important gastric dilatation in 34 cases (50%). The treatment has been composed of a gastroenterostomy (30 cases--44%), most of the time with a troncular vagotomy, of a pyloroplasty with vagotomy in 20 cases (29.5%) and of an inferior polar gastric resection in 18 cases (26.5%). The operative mortality was 2 cases (3%). The at distance-results (average follow-up of 7 years) show that 71% of the re-examined patients (45 cases) are classified Visick 1 or 2 and 9% visick 4. Ones concludes to the value of troncular vagotomy with gastroenterostomy which can be realised in all of the occasions and gives good functional results when the vagotomy with pyloroplasty seems to lie more frequently in state to uncertain functional results.

Adult↗
PubMed1981

[Mandibular condyle lacunae. A report on three cases (aneurysmal cyst, granuloma eosinophil and metastasis) (author's transl)].

Three cases of rare cystic tumors of the mandibular condyles are described: One case concerned a young 17-year-old girl with pain and joint crepitation due to an aneurysmal cyst. In the second case the presence of pain and a swelling led to the discovery of an eosinophil granuloma, with similar lesions in two other locations. A mandibular metastasis from a bronchial epithelioma was present in the third case.

Adolescent↗