16 research outputs found
Screening for tetrahydrobiopterin deficiencies using dried blood spots on filter paper
Tetrahydrobiopterin (BH4) deficiency among newborns with hyperphenylalaninemia must be rapidly diagnosed and distinguished from classical phenylketonuria (PKU) to initiate immediately specific treatment and to prevent irreversible neurological damage. The characteristic pattern of urinary pterins makes it possible to differentiate between PKU and BH4 deficiencies, and to identify different variants of BH4 deficiency. However, collection, storage, and shipment of urine samples for pterin analysis is cumbersome. A method for the measurement of different pterins (neopterin, biopterin, and pterin) in blood collected on filter paper was developed as a potential alternative to the screening for BH4 deficiencies in urine and for the monitoring of BH4 pharmacokinetics. Pterins pattern in blood spots was comparable with those in plasma and urine. We thus established reference values for pterins in blood spots in patients with hyperphenylalaninemia and identified new patients with GTP cyclohydrolase I deficiency, 6-pyruvoyl-tetrahydropterin synthase deficiency, and dihydropteridine reductase deficiency using dried blood spots on filter paper. (c) 2005 Elsevier Inc. All rights reserved
Lineage specific evolution and gene flow in Listeria monocytogenes is independent of bacteriophages
Listeria monocytogenes is a foodborne pathogen
causing systemic infection with high mortality. To
allow efficient tracking of outbreaks a clear definition
of the genomic signature of a cluster of related isolates
is required, but lineage-specific characteristics
call for a more detailed understanding of evolution. In
our work, we used core genome MLST (cgMLST) to
identify new outbreaks combined to core genome
SNP analysis to characterize the population structure
and gene flow between lineages. Whilst analysing
differences between the four lineages of L. monocytogenes
we have detected differences in the
recombination rate, and interestingly also divergence
in the SNP differences between sub-lineages. In addition,
the exchange of core genome variation between
the lineages exhibited a distinct pattern, with lineage
III being the best donor for horizontal gene transfer.
Whilst attempting to link bacteriophage-mediated
transduction to observed gene transfer, we found an
inverse correlation between phage presence in a
lineage and the extent of recombination. Irrespective
of the profound differences in recombination rates
observed between sub-lineages and lineages, we
found that the previously proposed cut-off of 10 allelic
differences in cgMLST can be still considered valid
for the definition of a foodborne outbreak cluster of
L. monocytogenes