Pédiatrie [News in paediatrics]

Every pediatrician will be confronted with newborns oryoung infants with skin lesions in proximity of the vertebral column. It is important not to miss a spinal dysraphism because of the risk of meningeal infection or of the possible presence of a tethered cord. A practical algorithm is presented. Non-accidental injury in young infants and toddlers is not rare but difficult to detect. Bruises and fractures are highly suspicious for non-accidental injury and should trigger specific investigations. Emergency departments and hospitals are switching from hypotonic to isotonic solutions as maintenance infusions of children. They reduce the risk of hyponatremia without increasing that of hypernatremia, and they should be used preferentially in the majority of pediatric clinical settings

PCR-based rapid genotyping of Stenotrophomonas maltophilia isolates

<p>Abstract</p> <p>Background</p> <p>All bacterial genomes contain repetitive sequences which are members of specific DNA families. Such repeats may occur as single units, or found clustered in multiple copies in a head-to-tail configuration at specific loci. The number of clustered units per locus is a strain-defining parameter. Assessing the length variability of clusters of repeats is a versatile typing methodology known as multilocus variable number of tandem repeat analysis (MLVA).</p> <p>Results</p> <p><it>Stenotrophomonas maltophilia </it>is an environmental bacterium increasingly involved in nosocomial infections and resistant to most antibiotics. The availability of the whole DNA sequence of the <it>S. maltophilia </it>strain K279a allowed us to set up fast and accurate PCR-based diagnostic protocols based on the measurement of length variations of <it>loci </it>carrying a variable number of short palindromic repeats marking the <it>S. maltophilia </it>genome. On the basis of the amplimers size, it was possible to deduce the number of repeats present at 12 different <it>loci </it>in a collection of <it>S. maltophilia </it>isolates, and therefore label each of them with a digit. PCR-negative regions were labelled 0. Co-amplification of two pairs of <it>loci </it>provided a 4-digit code sufficient for immediate subtyping. By increasing the number of <it>loci </it>analyzed, it should be possible to assign a more specific digit profile to isolates. In general, MLVA data match genotyping data obtained by PFGE (pulsed-field gel electrophoresis). However, some isolates exhibiting the same PCR profiles at all <it>loci </it>display distinct PFGE patterns.</p> <p>Conclusion</p> <p>The utilization of the present protocol allows to type several <it>S. maltophilia </it>isolates in hours. The results are immediately interpretable without the need for sophisticated softwares. The data can be easily reproducible, and compared among different laboratories.</p

Control of mRNA processing and decay in prokaryotes.

Post-transcriptional mechanisms operate in regulation of gene expression in bacteria, the amount of a given gene product being also dependent on the inactivation rate of its own message. Moreover, segmental differences in mRNA stability of polycistronic transcripts may be responsible for differential expression of genes clustered in operons. Given the absence of 5' to 3' exoribonucleolytic activities in prokaryotes, both endoribonucleases and 3' to 5' exoribonucleases are involved in chemical decay of mRNA. As the 3' to 5' exoribonucleolytic activities are readily blocked by stem-loop structures which are usual at the 3' ends of bacterial messages, the rate of decay is primarily determined by the rate of the first endonucleolytic cleavage within the transcripts, after which the resulting mRNA intermediates are degraded by the 3' to 5' exoribonucleases. Consequently, the stability of a given transcript is determined by the accessibility of suitable target sites to endonucleolytic activities. A considerable number of bacterial messages decay with a net 5' to 3' directionality. Two different alternative models have been proposed to explain such a finding, the first invoking the presence of functional coupling between degradation and the movement of the ribosomes along the transcripts, the second one implying the existence of a 5' to 3' processive '5' binding nuclease'. The different systems by which these two current models of mRNA decay have been tested will be presented with particular emphasis on polycistronic transcripts

In vivo mapping and characterization of rho-dependent transcription termination sites.

Abstract N406 published on J. Cell. Biochem., Supplement 12D

Exploring subunit interactions using interallelic complementation in the hisD gene.

Abstract 2416 published on The FASEB Journal