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Biomedical subjects

E Carpentier

Publications and source records attributed to E Carpentier.

At least 19 recordsLinked to original sources
PubMed2001

Increased production of active human beta(2)-adrenergic/G(alphas) fusion receptor in Sf-9 cells using nutrient limiting conditions.

Using the baculovirus/insect-cell expression vector system, we succeeded in obtaining a high yield of active human beta(2)-adrenergic receptor/G(alphas) fusion protein. This was achieved following high cell density production under nutrient-limiting conditions using a very low multiplicity of infection (MOI). This approach was found to significantly reduce inactive protein accumulation that occurred when production was done using conventional high MOI procedures. The maximum specific and volumetric yields of active receptor using this strategy increased by factors of two- and sixfold, respectively. Our results suggest that the increase in the ratio of active/total protein produced results from production under nutrient limitation. Since low multiplicity of infection offers many advantages for large-scale applications, we suggest that this simple production method should be considered when optimizing expression of G-protein-coupled receptors and other complex proteins.

Animals↗
PubMed2001

Regulation of a wheat actin-depolymerizing factor during cold acclimation.

We have previously shown that the wheat (Triticum aestivum) TaADF gene expression level is correlated with the plants capacity to tolerate freezing. Sequence analysis revealed that this gene encodes a protein homologous to members of the actin-depolymerizing factor (ADF)/cofilin family. We report here on the characterization of the recombinant TaADF protein. Assays for ADF activity showed that TaADF is capable of sequestering actin, preventing nucleotide exchange, and inducing actin depolymerization. In vitro phosphorylation studies showed that TaADF is a substrate for a wheat 52-kD kinase. The activity of this kinase is modulated by low temperature during the acclimation period. Western-blot analyses revealed that TaADF is expressed only in cold-acclimated Gramineae species and that the accumulation level is much higher in the freezing-tolerant wheat cultivars compared with the less tolerant ones. This accumulation was found to be regulated by a factor(s) encoded by a gene(s) located on chromosome 5A, the chromosome most often found to be associated with cold hardiness. The induction of an active ADF during cold acclimation and the correlation with an increased freezing tolerance suggest that the protein may be required for the cytoskeletal rearrangements that may occur upon low temperature exposure. These remodelings might be important for the enhancement of freezing tolerance.

Acclimatization↗
PubMed1996

Identification and characterization of a low temperature regulated gene encoding an actin-binding protein from wheat.

A cDNA corresponding to a putative actin-binding protein was cloned from a cold-acclimated wheat cDNA library. The cDNA, designated Wcor719, encodes a polypeptide of 142 amino acids with a calculated molecular mass of 15.8 kDa and a pI of 4.27. The protein has the two conserved domains identified as actin and phosphatidylinositol 4,5-biphosphate (PIP2) binding sites found in members of the cofilin family. Northern analyses revealed that Wcor719 transcript accumulation is rapid and strongly up-regulated by low temperature. This accumulation was greater in the tolerant winter wheat and rye species compared to the less tolerant ones. The rapidity of transcript induction and the significant homology with actin-binding proteins (ABP) from different organisms suggest that the product of this gene might be involved in the dynamic reorganization of the cytoskeleton during low temperature acclimation. It may also serve as a key factor in the signal transduction pathway during cold acclimation.

Acclimatization↗
PubMed1996

A blind study of the polymerase chain reaction for the detection of Mycobacterium tuberculosis DNA. Azay Mycobacteria Study Group.

SETTING: Nine French laboratories routinely involved in mycobacterial work. OBJECTIVE: To assess the detection of Mycobacterium tuberculosis in experimental samples by polymerase chain reaction (PCR) using the insertion sequence IS6110 as a target for deoxyribonucleic acid (DNA) amplification. DESIGN: Nine laboratories participated in a blind study of the detection of M. tuberculosis by PCR in 20 coded samples containing either a definite number of M. tuberculosis complex (positive samples) or environmental mycobacteria (four samples) or no mycobacteria (five samples). RESULTS: Five laboratories reported false-positive PCR results, with an average rate of 7%. All laboratories except one reported positive PCR results for samples containing 10(5) cfu/ml or more. M. tuberculosis DNA was detected in two thirds of samples containing 10(4) and 10(3) cfu/ml, and in one third of the samples containing 10(2) cfu/ml. CONCLUSION: The results of the study suggest that PCR using IS6110 as a target for DNA amplication is neither very sensitive nor really specific for the detection of M. tuberculosis.

DNA, Bacterial↗
PubMed1995

[Bacteriological diagnosis of tuberculosis: current hieratic classification of methods].

To assure the diagnosis of tuberculosis, one needs the observation, the isolation and the identification of the causative agent Mycobacterium tuberculosis. In this approach, the microscopic exam occurs as a fast but neither sensitive or specific test. The isolation on solid media is slow and needs more than three weeks before becoming positive. Nevertheless, it is a sensitive and specific one. The identification of the isolated strain and the study of sensitivity to antibiotic agents require an equal delay. Then, 2 months are necessary to achieve the analysis. The AIDS epidemic with the increase of opportunistic mycobacterial diseases, and the unexpected arrival of resistant Mycobacteria is creating as a difficult therapeutic problem. The cultivation in liquid media with the radiometric method (Bactec) shortens the time of culture by half. The genomic amplification assay has been hopeful because it allowed results in 2 days. However, some technical difficulties happen when the test is conducted and it is less sensitive than the isolation process. The hierarchical classification of the laboratory useful process to establish the diagnosis of tuberculosis disease remains the microscopic observation of the bacilli and their isolation. Today, the use of PCR alone does not assure the diagnosis of tuberculosis, however it may be used as a additional diagnostic test.

AIDS-Related Opportunistic Infections↗
PubMed1995

Scaphoid nonunion: treatment by open reduction, bone graft, and staple fixation.

Thirty-eight scaphoid nonunions were treated by iliac crest bone grafting and staple fixation. A distractor was inserted through an anterior incision and the scaphoid was distracted to restore its original length. The nonunion was then grafted and held with a staple. Consolidation was achieved in 36 cases despite 6 cases of partial avascular necrosis. Pain at the graft site, which was usually transient, was the only complication. Wrist extension was significantly improved. The main indication for this procedure is pseudarthrosis of the middle third of the scaphoid.

Adolescent↗
PubMed1995

Diagnosis of tuberculosis by Amplicor Mycobacterium tuberculosis test: a multicenter study.

The Amplicor Mycobacterium tuberculosis test is a new PCR assay for the direct detection of Mycobacterium tuberculosis from clinical samples. A multicenter study that included six laboratories was done to evaluate the Amplicor test in comparison with direct microscopy and culture (solid or radiometric media), and the culture method was used as the "gold standard." A total of 2,073 specimens, i.e., 1,749 respiratory specimens and 324 other specimens, were tested. A total of 184 cultures yielded M. tuberculosis. Of these 184 cultures, 77 (42%) were smear negative and 23 (12.5%) concerned extrapulmonary specimens. The sensitivity of the Amplicor test for all of the specimens and for extrapulmonary, smear-positive, and smear-negative specimens was 86, 83, 94.5, and 74%, respectively. The sensitivity of direct microscopy in comparison with that of culture was 58%. A total of 95% of patients with culture-proven tuberculosis were diagnosed by the Amplicor test, whereas direct microscopy detected mycobacteria in only 72% of these patients. The Amplicor test exhibited a high degree of specificity (98%). The assay was very rapid and easy to perform.

Bacteriological Techniques↗
PubMed1995

[Use of the Bactec TB 460 method for the bacteriological diagnosis of tuberculosis. Results of a multicenter study].

Isolation of Mycobacteria on Loewenstein-Jensen medium lasts many weeks. The use of Radiometric method (Bactec TB 460) reduces the delays. Results of 79,064 cultures are reported from a multicentric study associating 16 laboratories. The average was 4.8% of positivity and 2.51% of contamination. The comparison of the results with conventional method previously obtained shows that radiometric method is more sensitive and contaminations are less numerous. Concerning hemocultures the Bactec method is very usefull. Among 11,277 tests performed 907 were positive (8.04%). Mycobacterium avium was identified in 89% of the cases. Identification test utilizes Biochemical and NAP tests, but also more and more Nucleic probes. The antibiotic sensitivity is performed in five days. The mean delay of analysis is about 25 days, lessening by half the conventional method delays. Nevertheless, Bactec method has the following inconveniences: syringe inoculation, use of radiolabelled products, expensive cost.

Anti-Bacterial Agents↗
PubMed1994

Comparison of phenotypic methods and DNA hybridization for detection of methicillin-resistant Staphylococcus aureus.

One hundred thirty-eight Staphylococcus aureus isolates from patients with severe staphylococcal infections were collected in 15 French hospitals. Detection of the mec gene was performed by dot blot hybridization with a specific DNA probe. Dot blot results were used to characterize the isolates as methicillin susceptible (77 isolates) or resistant (61 isolates). The isolates were screened for methicillin resistance by an agar spread method on Mueller-Hinton plates containing oxacillin (2 and 10 micrograms/ml) and were incubated at 37 degrees C, with 10(8) CFU as the inoculum. MICs of oxacillin and methicillin were determined by the agar dilution method on Mueller-Hinton plates without NaCl, by using 10(5) CFU per spot, after 24 and 48h of incubation at 30 or 37 degrees C. Moderately elevated MICs were found for 20 isolates (14.5%). The mec gene was detected in six (30%) of the isolates expressing a low level of resistance to methicillin and/or oxacillin. As determined by comparison with probe hybridization results, the spread plate method with oxacillin at 2 micrograms/ml was more sensitive (sensitivity, 100%) and specific (specificity, 100%) than agar dilution with either methicillin or oxacillin in identifying methicillin resistance or susceptibility. Determinations of methicillin and oxacillin MICs by the agar dilution method had a specificity of 99 to 100% depending on the conditions of incubation, but the sensitivity was below 85% whatever the duration or temperature of incubation.

DNA, Bacterial↗
PubMed1993

[Mechanisms of adhesion of Staphylococci to biomaterials: effect of fusidic acid].

The production of slime, adherence to plastics and hydrophobicity are factors which regulate the colonisation of biomaterials by Staphylococci. The influence of fusidic acid on these 3 factors was studied by using 3 pairs of pathogenic strains of S. aureus and S. epidermidis. Each pair presented differences in the expression of one or several of these factors. The influence of fusidic acid was initially studied by determining the expression of these factors by these strains cultured in the presence of 0.03 mg/l and 0.5 mg/l of antibiotic. Hydrophobicity was measured by the Bath-test method, slime was detected by Trypan blue staining after fixation with Carnoy's fixative and adherence was determined on polystyrene. The variations observed were generally minor, except for S. epidermidis, high slime produces, which showed a reduced production. Using this collection of strains, we then selected mutants resistant to 2 micrograms/ml of fusidic acid. This resistance induced a reduction in the 3 colonisation factors and it can be proposed that strains resistant to fusidic acid have a lesser capacity to colonise than sensitive strains. The bacteria adhere to and colonise the majority of surfaces proposed to them [3, 7, 10]. This was the case for biomaterials used in medicine, whose number and diversity (catheters, prostheses) are continually increasing. Apart from thrombosis, the major complication is the development of infection. Coagulase positive or negative Staphylococci are very frequently responsible for this type of infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Adhesion↗
PubMed1993

[Maxillary metastasis of malignant thymoma].

The authors report a case of maxillary metastasis in the follow up of a malignant thymoma. It seems to be the first case reported in today's scientific literature. The clinical presentation, histopathological features and prognosis of malignant thymoma are discussed. The worse influence of distant metastasis on survival rate is state precisely.

Aged↗
PubMed1992

[Traumatic avulsion of the triceps brachialis tendon. A case report].

We report a triceps tendon avulsion (less than 40 cases reported in the medical literature). Clinical and radiological signs are: 1) Impossible elbow extension against gravity, 2) Flecks of avulsed osseous materiel from the olecranon on lateral elbow radiograph. Immediate surgical repair always produces good results.

Adolescent↗
PubMed1991

[Osteosynthesis of forearm fractures using a P.C.D. "Small fragments" plate from A.O instruments. Apropos of 283 screwed plates].

The authors report the results of using 283 P.C.D. "petits fragments" plates by A.O. instruments, inserted between 1980 and 1989 for internal fixation of 207 forearm fractures. These included 97 double forearm fractures, 34 isolated ulnar fractures, 30 isolated radial fractures, 24 Monteggia fractures, 13 Galeazzi fractures and 9 pseudoarthroses of the radius or ulna. The mean delay to consolidation was 3.3 months with a range of 2 to 15 months. Complications included 1 hypertrophic callus of the ulna; 3 pseudoarthroses, 7 cases of sepsis (6 ulnar, 1 radius i.e. 2.5%); no plate ruptures occurred in this series. 125 plates were removed after consolidation (after 18 months); the fracture recurred in only one case where the plate was removed after 8 months. Results are based on 203 operated patients (4 lost to follow up). Before treatment of the complication, results showed 150 very good results (73.2%), 44 good results (21.5%) 1 moderate (0.5%) and 10 poor results (4.8%). After treatment of the complications there were 156 very good results (77%), 46 good results (22.5%) and 1 moderate result. In summary, forearm fractures are no longer a problem in traumatology. The P.C.D. "petits fragments" plate of A.O. instruments would appear to be particularly adapted and a bulkier implant (4.5 screw) is not required.

Adolescent↗
PubMed1990

[Villonodular synovitis. An uncommon localization: the ankle. Apropos of a case].

The authors report an uncommon soft tissue tumor, a diffuse giant cell tumor of tendon sheath. The location is uncommon too, the ankle, behind tibial shaft and forward achilleus tendon. The primary diagnosis of ankle and leg lymphoedema, has been for a long time. But CT Scan and MRI allowing the discovery of a firm and multinodular mass, have permitted surgical excision and histological diagnosis. This case agrees with the literature review. The pigmented villonodular synovitis is rather uncommon in comparison to localized form. Young people and lower extremities are more affected; symptoms are of relatively long duration. Histological examination gives diagnosis but surgical excision has to remove the tumor completely as possible because of local recurrence rate of about 50%.

Adult↗
PubMed1989

[Congenital pseudarthrosis of the legs and the Ilizarov method. Apropos of 4 cases].

Four cases of congenital pseudarthrosis were treated by the Ilizarov method and consolidation obtained by 3.5 months in three patients who had all undergone several previous surgical procedures. Although the length of follow up is short (maximum 3.5 years) consolidation occurred quicker than by traditional methods. This technique also permitted both simultaneous correction of axial malalignment and leg lengthening. We think that this method has a place as a salvage procedure except where the distal fragment is very thin or dystrophic.

Adolescent↗
PubMed1988

[Meniscal lesions in so-called "isolated" ruptures of the anterior cruciate ligament. Apropos of 59 cases].

Between December 1984 and March 1987, i.e. a period of 27 months, the authors operated on 59 "isolated" fresh ruptures of the ACL with routine evaluation of the posterior horns of the medial and lateral menisci. Lesions were investigated either by arthroscopy (23 cases) or by anterior arthrotomy with routine medial and lateral retro-ligamentous counter-incision (36 cases). This revealed 21 lesions of the medial meniscus (i.e. 35.5%) and 38 lesions of the lateral meniscus (i.e. 64.5%). Lesions of both menisci were present in 16 knees (27%) and only 16 knees (27%) were found to be free of any meniscal lesion. The majority of meniscal lesions were viable and could be sutured in 86% of cases for the medial meniscus and 87% of cases for the lateral meniscus. From the standpoint of operative technique, posterior lesions are relatively poorly visualized by arthroscopy (notably concerning the posterior horn of the medial meniscus though it is easier to assess the stability of the meniscus by this technique using the palpating hook. Lesions are well visualized by medial and lateral retroligamentous counter-incisions, but it is difficult to assess meniscus stability. Finally it should be noted that all of these ruptures of the ACL were dealt with by reconstruction of the central pivot either by suture and a strengthening procedure (semitendinous) or by ligament plasty from the outset.

Arthroplasty↗