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J Elion

Publications and source records attributed to J Elion.

At least 127 records · Page 7Linked to original sources
PubMed1992

DNA restriction fragment length polymorphism differentiates recurrence from relapse in treatment failures of Streptococcus pyogenes pharyngitis.

In the evaluation of treatment failure in Streptococcus pyogenes pharyngitis it is necessary to distinguish between persistence of the original streptococcus and acquisition of a new strain. We used the analysis of restriction fragment length polymorphism (RFLP) of total DNA and of ribosomal DNA (rDNA) regions (ribotypes) as epidemiological tools to compare 43 pre- and post-treatment S. pyogenes strains obtained from 20 patients. In 16 cases pre- and post-treatment strains gave indistinguishable RFLP patterns of total DNA, strongly suggesting relapse with the same strain. However, in four cases different patterns were obtained for the pre- and post-treatment isolates, indicating recurrence due to the acquisition of a new strain. Ribotyping did not improve discrimination among strains. Thus, analysis of DNA RFLP is a promising method for distinguishing recurrence from relapse in failures of pharyngitis treatment.

DNA, Bacterial↗
PubMed1992

Molecular epidemiology unravels the complexity of neonatal Escherichia coli acquisition in twins.

Combined analysis of restriction fragment length polymorphism of regions of genes coding for rRNA (ribotyping) and esterase electrophoretic typing was used to document neonatal acquisition of Escherichia coli in twins. Our study shows vertical mother-to-infant transmission of one strain of E. coli to one twin and the development of neonatal septicemia with a distinct nonvirulent carboxylesterase type B1 E. coli strain for the other twin.

Adult↗
PubMed1992

Ribotyping provides efficient differentiation of nosocomial Serratia marcescens isolates in a pediatric hospital.

Ribotyping with a nonradioactive probing system was used for the epidemiological evaluation of 15 Serratia marcescens nosocomial strains isolated from the stools of 12 children with no apparent illness in five different hospital wards over a 20-day period. Our results indicate that the occurrence of S. marcescens colonization was the result of the spread of a single epidemiological strain in the hematology ward, the oncology ward, and the gastroenterology ward and in two neonates in the neonatology ward, suggesting cross-contamination between the patients in these four wards. This isolate was genotypically unrelated to the bacterial strain found in the three other patients in the neonatology ward. Interestingly, one patient in the neonatology ward harbored these two genotypically different strains. Finally, the patient in the intensive care unit was colonized with a different strain. We find ribotyping to be a more reliable technique than biochemical typing. The results of ribotyping are more easily interpreted than are those of total DNA analysis, with an equivalent degree of discrimination.

Bacterial Typing Techniques↗
PubMed1992

[Epidemiology of Chlamydia trachomatis using analysis of gene encoding of the major outer membrane protein].

One hundred and eight clinical strains and 24 reference strains of C. trachomatis were typed using differential restriction mapping of omp1, the gene which encodes the major outer membrane protein. The gene was obtained by polymerase chain reaction (PCR). This molecular typing method correlated well with serological typing. Eighty-four per cent of clinical strains were typed using the enzyme AluI alone. Heterogeneity was looked for among the most common serovars (E, F, and D; 62%, 17%, and 9%, respectively). Analysis of the PCR-amplified fourth variable domain of omp1 using denaturing gradient gel electrophoresis followed by direct sequencing of the variants disclosed substantial heterogeneity within the D serovar. Conversely, serovars E and F were homogeneous, with however a single variant strain of serovar E.

Bacterial Outer Membrane Proteins↗
PubMed1992

[HbD Iran-beta-thalassemia association in a Tunisian family].

A nine-year-old boy from Béjà (North-Western Tunisia) was found to have both HbD Iran and beta-thalassemia. This patient presented with anemia and slight enlargement of the spleen and had a history of acute episodes of hemolysis. Structural studies on this hemoglobin variant used several miniaturized techniques, mainly carboxy-methyl-cellulose chromatography, reverse-phase high performance liquid chromatography and manual peptide sequencing using Chang's technique. The glutamic acid in position 22 on the beta chain was found to be replaced by a glutamine, establishing the diagnosis of HbD Iran. Concomitant presence of a thalassemia trait was suggested by the finding in the index patient of microcytosis, hypochromia and increased HbA2. The family study confirmed this patient's combined heterozygous anomalies, showing the D trait in the father and the beta thalassemia trait in the mother. The same combination was found in the index patient's sister who was, however, free of clinical symptoms. The explanation of this difference in clinical expression was provided by the ADN study which disclosed deletion of an alpha gene in the girl. The resulting alpha chain deficiency counterbalanced the beta chain deficiency.

Amino Acid Sequence↗
PubMed1991

Rapid genotyping of the Chlamydia trachomatis major outer membrane protein by the polymerase chain reaction.

Twenty one Chlamydia trachomatis reference strains and 40 clinical isolates belonging to the lymphogranuloma venerum (LGV) and trachoma biovars were genotyped by differential restriction mapping of the major-outer-membrane-protein gene (MOMP) obtained by the polymerase-chain reaction (PCR). AluI digestion of the PCR product distinguishes eight MOMP-genotypes corresponding to 8 serovars. Six additional enzymes (NlaIII, CfoI, EcoRI, HinfI, DdeI and FokI) further permit the discrimination of 10 MOMP-genotypes corresponding to the 10 remaining serovars of the species. AluI alone allows direct typing of 78% of the clinical isolates. AluI digestion patterns of mouse C. trachomatis biovar, a C. pneumoniae and two C. psittaci strains, studied for comparison, were clearly distinguishable from one another and from the C. trachomatis LGV and trachoma strains. These results indicate that MOMP genotyping by PCR is a valuable molecular tool for studying C. trachomatis epidemiology.

Bacterial Outer Membrane Proteins↗
PubMed1991

Increased protein binding to a -530 mutation of the human beta-globin gene associated with decreased beta-globin synthesis.

Although some cases of the syndrome of hereditary persistence of fetal hemoglobin (HPFH) have been correlated with mutations causing a change in the binding of trans-acting factors to DNA sequences flanking the gamma-globin gene, this mechanism has not been described in beta-thalassemias upstream of the canonical promoter of the beta-globin gene. In this report we describe such a change in binding of a protein that may explain a silent carrier phenotype of beta-thalassemia. We have previously demonstrated the binding of a protein (BP1) derived from a nuclear extract of human K562 cells to DNA 5' to the human beta-globin gene in a region having a negative regulatory function. The binding of BP1 in this region can be detected by DNAse I footprinting and by gel mobility shift analysis. We have now compared binding of BP1 to the normal sequence and a mutated sequence (+ATA/-T at -530 bp from the cap site) from the silent carrier of beta-thalassemia. Using mobility shift assays we show that BP1 binds about nine times more strongly to the mutated sequence than the normal sequence. These results suggest the possibility that the decreased expression of the beta-globin gene exhibited by the carrier may be due, at least in part, to tighter binding of a protein which functions as a negative control element or repressor.

Base Sequence↗
PubMed1991

Preliminary report on the use of desferrioxamine in the treatment of Plasmodium falciparum malaria.

The administration of 0.5 g (IM) of desferrioxamine every 12 hr for 3 days with 25 mg/kg (total dose for three days) of chloroquine abated the parasitemia of Plasmodium falciparum infected individuals more rapidly than chloroquine alone. Two patients with in vitro evidence of total or partial resistance to chloroquine also were successfully treated with the combination of drugs, and were free of parasitized red cells by day 7. Further clinical trials and development of desferrioxamine in the treatment of P. falciparum are warranted.

Animals↗
PubMed1991

Nucleotide sequence evidence of the unicentric origin of the beta C mutation in Africa.

The origin of the beta C mutation was studied by characterizing nucleotide sequence polymorphisms on beta C chromosomes of patients from various African countries. In the majority of cases, the beta C mutation was found in linkage disequilibrium with a single chromosomal structure as defined by classical RFLP haplotypes, intergenic nucleotide sequence polymorphisms immediately upstream of the beta-globin gene, and intragenic beta-globin gene polymorphisms (frameworks). In addition, three atypical variant chromosomes carrying the beta C mutation were observed, and are most probably explained either by a meiotic recombination (two cases) or by one nucleotide substitution occurring in an unstable array of tandemly repeated sequences (one case). These data demonstrate the unicentric origin of the beta C mutation in central West Africa, with subsequent mutational modification in a small number of instances. The data also supports gene flow of the beta C chromosome from subsaharan Africa to North Africa.

Africa↗
PubMed1991

Complexity of Pseudomonas aeruginosa infection in cystic fibrosis: combined results from esterase electrophoresis and rDNA restriction fragment length polymorphism analysis.

Esterase electrophoretic typing and restriction fragment length polymorphism of ribosomal DNA regions (ribotyping) were used to differentiate 102 Pseudomonas aeruginosa clinical isolates obtained from chronic lung infection in 23 patients with cystic fibrosis (CF) and two reference strains (including the type strain ATCC 10145). Twenty-five zymotypes were obtained with the former method and 16 ribotypes with the latter. Combination of the two typing systems led to the finding of 30 different types. Our data highlights the physiopathological complexity of P. aeruginosa infection in CF as, in six individual cases, several types were found among isolates from a given patient. On the other hand, two unique types were found in two and three patients respectively, raising the possibility of cross-infections.

Cystic Fibrosis↗
PubMed1991

Restriction pattern of the major outer-membrane protein gene provides evidence for a homogeneous invasive group among ruminant isolates of Chlamydia psittaci.

Thirty-six ruminant isolates of Chlamydia psittaci, previously classified as invasive or non-invasive in a mouse model of virulence, were compared by analysing AluI restriction patterns of the major outer-membrane protein (MOMP) gene after DNA amplification by the polymerase chain reaction. The 24 invasive isolates, although from various origins, all belonged to serotype 1 and represented a strictly homogeneous group sharing a specific MOMP-gene restriction pattern that was not observed in the non-invasive strains. On the other hand, the 12 non-invasive strains, although all belonging to serotype 2, constituted a heterogeneous group with eight distinct MOMP-gene restriction patterns. However, all eight patterns shared a 180 bp fragment or the corresponding restricted fragments of 110 and 70 bp. MOMP-gene restriction patterns also clearly distinguished the ruminant strains from an avian C. psittaci isolate, a C. pneumoniae isolate and two C. trachomatis isolates which were studied for comparison. The homogeneous character of the invasive C. psittaci strains argues strongly for their genetic relatedness. Our results illustrate the usefulness of the MOMP-gene restriction mapping in typing chlamydiae.

Animals↗
PubMed1991

DNA restriction fragment length polymorphism differentiates crossed from independent infections in nosocomial Xanthomonas maltophilia bacteremia.

Restriction fragment length polymorphisms of total DNA and rDNA were used to study the relationship between 11 isolates of Xanthomonas maltophilia, obtained from seven patients with nosocomial bacteremia in four distinct wards of a single hospital, and the type strain of the species, ATCC 13637. Our results indicated that there were episodes of cross-infection among the patients of two wards, but there were also independent infectious episodes in the two other wards.

Child↗
PubMed1991

Evidence for the genetic unrelatedness of nosocomial vancomycin-resistant Enterococcus faecium strains in a pediatric hospital.

Vancomycin-resistant enterococci are now found with increasing frequency. Up to now, epidemiological studies of enterococci have been limited by the lack of convenient and accessible methods for comparing strains. In this study, we report an epidemiological investigation on 16 nosocomial vancomycin-resistant Enterococcus faecium strains isolated from 15 patients in four different wards of a children's hospital over a period of 17 months. Analysis of restriction fragment length polymorphism (RFLP) of total DNA and of ribosomal DNA regions (ribotyping) was used as a typing approach. Each strain produced a different total DNA RFLP pattern after HindIII and PvuII digestion, except for two strains that were isolated from a single patient and that gave indistinguishable patterns. In our system, ribotyping was less discriminative than RFLP of total DNA. This approach, therefore, shows the genetic unrelatedness of the nosocomial strains studied and excludes patient-to-patient strain transmission either in the same ward or between wards.

Adolescent↗
PubMed1991

Origin and spread of beta-globin gene mutations in India, Africa, and Mediterranea: analysis of the 5' flanking and intragenic sequences of beta S and beta C genes.

Nucleotide polymorphisms of both the 5' flanking and intragenic regions of the human beta-globin gene were investigated by directly sequencing genomic DNA after amplification by the polymerase chain reaction in 47 subjects homozygous for the beta S or the beta C mutation. The sickle-cell mutation was found in the context of five different haplotypes defined by eight nucleotide substitutions and various structures of a region of the simple repeated sequence (AT) chi Ty. All subjects from the same geographic origin bear an identical chromosomal structure, defining the Senegal-, Bantu-, Benin-, Cameroon-, and Indian-type chromosomes. These results strengthen our previous conclusions about the multiple occurrence of the sickle-cell mutation. The Benin-type chromosome was also found among Algerian and Sicilian sickle-cell patients, whereas the Indian-type chromosome was observed in two geographically distant tribes, illustrating the spread of these sickle-cell genes. We also found that the intragenic sequence polymorphisms (frameworks) are not always in linkage disequilibrium with the BamH I polymorphism downstream from the beta-globin gene, as had been previously observed. Finally, we present a tentative phylogenetic tree of the different alleles at this locus. Some polymorphisms of this sequence might be contemporary with our last common ancestor, the great apes, that is, about 4-6 millions years old.

Africa↗
PubMed1991

HLA-DQA1 and DQB1 alleles in French and Algerian type 1 diabetic subjects.

Some alleles of the HLA-DQB1 and DQA1 loci are preferentially associated with susceptibility to type 1 (insulin-dependent) diabetes mellitus (IDDM). Analysis of the HLA-DQ genetic profile may therefore become important for the screening of subjects at risk of IDDM. However ethnic variations in the genetic profile can occur and require background knowledge of the HLA-DQ allelic distribution before screening campaigns. In the present work, HLA-DQA1 and DQB1 genes have been analyzed, after PCR amplification of the genomic DNA, in French and Algerian control subjects (a total of 148) and diabetic patients (a total of 107). Allelic distributions have been investigated in view of a) possible inter-ethnic differences; b) identification of risk and protective alleles and c) the prevalence of DQB1 aspartate 57 negative and DQA1 arginine 52 positive alleles in control and diabetic groups. The DQB1 allelic distribution was similar in both control groups; alleles negative for aspartate at position 57 were 48% in French and 50% in Algerian. In both diabetic groups, the prevalence of alleles negative for aspartate at position 57 was significantly higher: 91% (French) and 81% (Algerian) (p less than 0.001). A majority of patients were homozygote for DQB1 Asp 57 negativity: 83% (French) and 63% (Algerian). The highest relative risk was associated with HLA-DQB1 0201/0302 heterozygosity. The HLA-DQA1 allelic distribution was also similar in French and Algerian controls. Alleles positive for arginine (ARG+) at position 52 were 50% (French) and 57% (Algerian) of controls. In both diabetic groups the prevalence of alleles positive for arginine at position 52 was significantly higher: 78% (French) and 84% (Algerian).(ABSTRACT TRUNCATED AT 250 WORDS)

Algeria↗