Prospective monitoring and quantitation of residual blasts in childhood acute lymphoblastic leukemia by polymerase chain reaction study of delta and gamma T-cell receptor genes.

We have developed a strategy based on polymerase chain reaction (PCR) for detecting all possible gamma T-cell receptor (gamma TCR) rearrangements and the most common delta TCR rearrangements found in B-lineage and T-acute lymphoblastic leukemia (T-ALL). The segments amplified from blasts are then directly sequenced to derive clonospecific probes. From a series of 45 patients aged 1 to 15 years (42 B-lineage ALL, 3 T-ALL), 35 (83%) could be followed for minimal residual disease with at least one clonospecific probe.

Differentiation of Escherichia coli strains using randomly amplified polymorphic DNA analysis.

Fifty-nine Escherichia coli strains isolated from 54 unrelated patients over a six-year period, as well as the reference strain of the species, were studied by analysis of randomly amplified polymorphic DNA (RAPD) to assess the usefulness of this genotyping approach in molecular epidemiology. Using a 10-mer oligonucleotide primer, 28 different RAPD fingerprints were distinguished among the 60 strains previously delineated in 36 ribotypes by EcoRI and HindIII digests. The patterns were reproducible and stable after in vitro and in vivo studies.

Arbitrarily primed polymerase chain reaction provides rapid differentiation of Proteus mirabilis isolates from a pediatric hospital.

During a systematic survey, maternal carriage of Proteus mirabilis was found over a 25-day period in 18 pregnant women admitted to the delivery ward of our hospital maternity. Five neonates born to these mothers were found to be colonized with P. mirabilis.

Identification of a clone of Escherichia coli O103:H2 as a potential agent of hemolytic-uremic syndrome in France.

In a French multicenter study, six verocytotoxin-producing Escherichia coli strains were isolated from the stools of 6 of 69 children suffering from hemolytic-uremic syndrome. All strains belonged to serotype O103:H2, a serotype commonly associated with diarrhea in weaned rabbits in France. To determine whether the strains from humans and rabbits were genetically related, they were compared by analyzing their esterase electropherotypes and the restriction fragment length polymorphisms of the ribosomal DNA regions.

Molecular analysis of multiply recurrent meningitis due to Escherichia coli K1 in an infant.

Bacterial DNA polymorphism was used to document the occurrence of three separate episodes of meningitis caused by Escherichia coli K1 in an infant. The methods employed included determination of the restriction fragment length polymorphism of total DNA and of ribosomal DNA regions as well as DNA fingerprinting by the arbitrarily primed polymerase chain reaction. By these three genotypic approaches, the three isolates obtained from the infant's cerebrospinal fluid on days 9, 34, and 70, respectively, were found to share the same patterns, which were different from the patterns of control strains.