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Biomedical subjects

C Carlier

Publications and source records attributed to C Carlier.

At least 55 records · Page 3Linked to original sources

Retinol, beta-carotene and alpha-tocopherol status in a French population of healthy children.

The serum of 392 French healthy children aged 1-16 years was analysed for vitamin A, vitamin E, beta-carotene and cholesterol contents. The study group consisted in 185 females and 207 males, living in the area of Tours, France. The mean serum values are 42.05 +/- 12.0 micrograms/dl for vitamin A, 572 +/- 381 micrograms/l for beta-carotene and 9.5 +/- 2.5 mg/l for vitamin E. According to sex distribution, mean values of studied micronutrients levels are higher in boys than in girls, but not significantly. Vitamin A and vitamin E serum levels increased with age. Vitamin E peripheral level is strongly correlated with total cholesterol serum value. The results are compared to those of underdeveloped countries children groups studies. At least, decreased vitamins levels are observed among five per cent of children and are examined as being at risk to develop a deficiency.

Adolescent↗

[Pitfalls in phlebography].

Despite the progress in functional investigation procedures, phlebography remains the standard test in venous disease of the lower extremities. The development of better quality contrast media has significantly improved patients tolerance. After a review of the regular, routine procedure, the authors stress the technic's pitfalls. Uncomplicated pitfalls are air bubbles, Venturi's effect, venous malformations, and superimposed venous axes or gases. This type of problems is easily circumvented. Flow images caused by confluent axes of high-flow veins (internal iliac veins, renal veins) or layer courants (gutter effect) are presented as a reminder. Compression images are often more treacherous: related to normal veins: compression of left iliac vein by aortic junction; of inferior vena cava by enlarged aorta or by osteophyte; tourniquet too low, iliac vein compressed by a dilated bladder; or compression due to intramuscular hematoma,... related to pathological veins: to be mentioned are bridle-caused obstruction of the popliteal vein (Klippel-Trénaunay syndrome), and retroperitoneal fibrosis. Although the present description of phlebography-related pitfalls is neither new, nor exhaustive, it should be reconsidered, as phlebography of the lower limbs, while being currently better tolerated, is still an update technic that needs to be rendered more reliable.

Constriction↗

Conjugative plasmid transfer from Enterococcus faecalis to Escherichia coli.

The possibility of transfer of genetic information by conjugation from gram-positive to gram-negative bacteria was investigated with a pBR322-pAM beta 1 chimeric plasmid, designated pAT191. This shuttle vector, which possesses the tra functions of the streptococcal plasmid pAM beta 1, was conjugatively transferred from Enterococcus faecalis to Escherichia coli with an average frequency of 5 x 10(-9) per donor colony formed after mating.

Conjugation, Genetic↗

[Percutaneous angioscopy of the iliac and femoral arteries].

Very few papers about peripheral angioscopy are reported in literature. Percutaneous angioscopy (P.T.A.) of 25 peripheral arteries (21 iliac and 4 femoral arteries) have been performed by the authors without surgery and without anesthesia. Three observations are selected. The first one demonstrates an eccentric stenosis altering its diameter during pulsations; an irregular ulcerated atheroma is observed. The second case shows the signs of a centric atheroma with an intimal fragment. The last one is an intimal dissection due to PTA. The prospective aspects of this new technique are discussed.

Aged↗

Impression cytology with transfer: an easy method for detection of vitamin A deficiency.

We described a new method to stain epithelial cells harvested by ocular impression. The cells are immediately transferred on a glass slide after the sampling; this transfer permits a very simple staining and easier reading by light microscopy. The results are compared with those obtained with the previous techniques and confirm ocular impression as a good help for vitamin A status determination.

Conjunctiva↗

Nucleotide sequence of the kanamycin resistance determinant of the pneumococcal transposon Tn1545: evolutionary relationships and transcriptional analysis of aphA-3 genes.

The nucleotide sequence of the kanamycin resistance determinant aphA-3 encoded by transposon Tn1545 from Streptococcus pneumoniae was determined and compared to those of plasmids pJH1 and pIP1433 from Streptococcus faecalis and Campylobacter coli, respectively. The three sequences were found to be identical and differed by two substitutions and the deletion of a codon from that of plasmid pSH2 from Staphylococcus aureus. Comparison of the 5' noncoding sequences indicated that the regions containing the aphA-3 gene in pJH1 and in Tn1545 evolved independently by deletion from a sequence similar to that found in pIP1433. In the latter plasmid, aphA-3 is transcribed from a promoter, P1, which is flanked by two 12-base pair direct repeats. The rearrangement observed in pJH1 removed one of these recombinogenic sites and altered the -10 and 3' flanking sequences of P1. The promoter thus generated. P1', allows expression of similar level of kanamycin resistance as P1. However, fusion experiments carried out with a promotorless chloramphenicol acetyltransferase gene indicated that the canonical promoter P1 is significantly less efficient than P1'. From analysis of the thermodynamic properties of these promoters, we conclude that this difference in strength reflects the melting properties of the -10 sequences. The transition from pIP1433 to pJH1 may correspond to the progression of a molecule structurally unstable to a more stable one combined with the need to maintain an efficient promoter upstream of the aphA-3 gene. The deletion event in Tn1545, which occurred between the two 12-base pair directly repeated sequences, removed P1 in its entirety.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗

Tn1545: a conjugative shuttle transposon.

Tn1545, from Streptococcus pneumoniae BM4200, confers resistance to kanamycin (aphA-3), erythromycin (ermAM) and tetracycline (tetM). The 25.3 kb element is self-transferable to various Gram-positive bacterial genera where it transposes. Tn1545 was cloned in its entirety in the recombination deficient Escherichia coli HB101 where it was unstable. The three resistance genes aphA-3, ermAM and tetM were expressed but were not transferable to other E. coli cells. Tn1545 transposed from the hybrid plasmid to multiple sites of the chromosome of its new host. The element re-transposed, at a frequency of 5 X 10(-9), from the chromosome to various sites of a conjugative plasmid where it could be lost by apparently clean excision. The element transformed and transposed to the chromosome of Bacillus subtilis. The properties of the conjugative shuttle transposon Tn1545 may account for the recent emergence of genes from Gram-positive bacteria in Gram-negative organisms.

Anti-Bacterial Agents↗

Physical analysis of the conjugative shuttle transposon Tn1545.

The conjugative shuttle transposon Tn1545 from Streptococcus pneumoniae confers resistance to kanamycin (aphA-3), erythromycin (ermAM), and tetracycline (tetM). The 25.3-kb element is self-transferable to various gram-positive bacterial genera where it transposes. Tn1545 is also capable of transposition, but not of conjugation, after cloningoff Escherichia coli. Analysis of the element by restriction endonucleases, molecular cloning, electron microscopy of heteroduplexes, DNA hybridization, and sequencing allowed us to establish a physical map of Tn1545, localize the resistance genes, determine their direction of transcription, and compare them with other characterized resistance determinants, and show that Tn1545 is not flanked by large terminal repeated sequences in opposite orientation.

Chromosome Mapping↗

Transposable multiple antibiotic resistance in Streptococcus pneumoniae.

A mobile genetic element, designated Tn1545, was detected in the chromosome of Streptococcus pneumoniae BM4200, a clinical isolate multiply resistant to antibiotics. The 25.3 kb element conferred resistance to kanamycin and structurally related aminoglycosides by synthesis of a 3'-aminoglycoside phosphotransferase type III (aphA-3), to macrolide-lincosamide-streptogramin B-type antibiotics (ermAM), and to tetracycline (tetM). Tn1545 was self-transferable to a recombination deficient S. faecalis strain where it was able to transpose to various sites, induce insertional mutations and was apparently cleanly excised. The element also conjugated to and transposed to the chromosome of S. faecalis, S. lactis, S. diacetylactis, S. cremoris, S. sanguis, Staphylococcus aureus, and Listeria monocytogenes. The properties of the conjugative transposon Tn1545 could account for the sudden emergence, rapid dissemination, and stabilisation of multiple resistance to antibiotics in S. pneumoniae in the absence of plasmids.

Aminoglycosides↗

Emergence of aminoglycoside 3-N-acetyltransferase IV in Escherichia coli and Salmonella typhimurium isolated from animals in France.

We studied two outbreaks of calf salmonellosis caused by apramycin and gentamicin-resistant Salmonella typhimurium strains. In both cases, the responsible strains were resistant to ampicillin, chloramphenicol, kanamycin, streptomycin, tetracycline, and trimethoprim; one strain was also resistant to nalidixic acid in one outbreak. A systematic survey of the intestinal Escherichia coli strains of calves from the two affected flocks showed that 11 of 24 animals sampled were also colonized by apramycin- and gentamicin-resistant E. coli strains. These isolates belonged to four biotypes and were resistant to ampicillin, chloramphenicol, kanamycin, streptomycin, tetracycline, trimethoprim, and nalidixic acid. All of the strains were resistant to high levels of apramycin (MICs, 512 to 1,024 micrograms/ml) and to gentamicin (MICs, 8 to 32 micrograms/ml), and these resistances were always transferred en bloc. In S. typhimurium, this coresistance was borne by plasmids that were approximately 39 kilobases long (outbreak 1) or 90 kilobases long (outbreak 2), whereas in E. coli, the coresistance was due to plasmids that were approximately 110 kilobases long in both outbreaks. The two plasmids of Salmonella and four plasmids of E. coli encoded type IV aminoglycoside 3-N-acetyltransferases. The intensive use of curative and preventive treatments in calf production could be responsible for the emergence of enzymic resistance to apramycin and gentamicin.

Acetyltransferases↗

Plasmid-mediated resistance to lincomycin by inactivation in Staphylococcus haemolyticus.

Staphylococcus haemolyticus BM4610 was resistant to high levels of lincomycin and susceptible to macrolides, clindamycin, and streptogramins. This resistance phenotype, not previously reported for a human clinical isolate, was due to inactivation of the antibiotic. The gene conferring resistance to lincomycin in strain BM4610 was carried by a 2.5-kilobase plasmid, pIP855, which was cloned in Escherichia coli. Plasmid pIP855 caused inactivation of both lincomycin and clindamycin in S. haemolyticus and in E. coli but conferred detectable resistance to lincomycin only in S. haemolyticus and to clindamycin only in E. coli.

Clindamycin↗

Characterization of high-level aminoglycoside resistance in a strain of Streptococcus pneumoniae.

The aminoglycoside phosphotransferase (APH)(3')(5'')-III has been characterized from Streptococcus pneumoniae BM4200, which is resistant to high levels of aminoglycosides. The phosphotransferase was apparently chromosomally-encoded and was responsible for the high-level resistance. The enzyme was not notably pH-dependent, was heterogeneous after isoelectric focusing, with pI values of approximately 4.8 and 5.1, and had an apparent molecular weight of 32 500 after SDS-PAGE.

Aminoglycosides↗

Transferable plasmid-mediated antibiotic resistance in Acinetobacter.

Acinetobacter calcoaceticus strain BM2500 was resistant to ampicillin, aminoglycoside-aminocyclitols, chloramphenicol, sulfonamides, and high levels of trimethoprim. Resistance to ampicillin was due to the presence of a beta-lactamase (TEM-1) and the aminoglycoside-aminocyclitol resistance was mediated by phosphotransferase (APH(3')(5")I) and adenylyltransferase (AAD(3)(9] activities. The resistance genes were carried by a 167 kilobase plasmid, pIP1031, belonging to incompatibility group 6-C; the plasmid was self-transferable, at extremely low frequency, to Escherichia coli by conjugation. Plasmid pIP1031 DNA was analyzed by agarose gel electrophoresis following restriction endonuclease digestion, by nucleic acid hybridization, and by CsCl analytical density gradient ultracentrifugation. The results support the hypothesis that plasmid pIP1031 may have been acquired recently by strain BM2500.

Acinetobacter↗

Aminoglycoside-modifying enzyme content of a multiply resistant strain of Streptococcus faecalis.

Streptococcus faecalis strain BM6217 was resistant to high levels of all the clinically useful aminoglycoside antibiotics. This broad aminoglycoside resistance was mediated by constitutively synthesized phosphotransferase, acetyltransferase, and adenylyltransferase activities. It was inferred that phosphorylation occurred at the 3', 5", and 2"-hydroxyl groups, acetylation at the 6'-amino group, and adenylylation, probably, at the 6-hydroxyl group of the aminoglycosides. Strain BM6217 remained susceptible to the aminocyclitol spectinomycin but the combination of penicillin G with that antibiotic appeared antagonistic to this strain.

Aminoglycosides↗

The chromosomal 3',5"-aminoglycoside phosphotransferase in Streptococcus pneumoniae is closely related to its plasmid-coded homologs in Streptococcus faecalis and Staphylococcus aureus.

The apparently chromosomally encoded 3',5"-aminoglycoside phosphotransferase (type III), from the high-level aminoglycoside-resistant Streptococcus pneumoniae BM4200, was compared with homologous enzymes coded for by the plasmids pJH1 and pSH2, originally isolated from Streptococcus faecalis and Staphylococcus aureus, respectively, and also found in a wild strain of S. aureus, BM4600. The enzymes appeared to be indistinguishable, and we conclude that the gene encoding 3',5"-aminoglycoside phosphotransferase (type III) can cross generic barriers within gram-positive cocci.

Enterococcus faecalis↗

A plasmid which does not encode the aminoglycoside phosphotransferase in the butirosin-producing strain of Bacillus circulans.

Bacillus circulans NRRL B-3312 produces the aminoglycoside antibiotic butirosin and encodes an aminoglycoside 3'-phosphotransferase. We detected a 48 kilobase plasmid, pIP850, in this strain; this was analyzed by agarose gel electrophoresis following digestion with EcoRI restriction endonuclease and by nucleic acid hybridization. The results obtained indicate that plasmid pIP850 does not carry the structural gene for the aminoglycoside modifying enzyme.

Anti-Bacterial Agents↗