Impacts on human mortality due to reductions in PM10 concentrations through different traffic scenarios in Paris, France.

OBJECTIVES: Air pollution is a well-known burden for population health and health systems worldwide. Reduction in air pollution is associated with improvements in mortality and rates of respiratory, cardiovascular and other diseases. Though air quality is a problem globally, efforts to lower air pollutant concentrations are usually regional or local. In industrialized countries, most urban air pollution is caused by vehicles, suggesting reductions in traffic would result in reductions of pollution. However, detailed data on how such reductions can be achieved and impact public health is just beginning to emerge, and other influencing factors, including vehicle flow or urban landscape are largely unaccounted for. METHODS: We utilized a unique combination of vehicle emission measurements combined with simulations of traffic and vehicle variations, as well as urban topographies, to quantify health impacts of PM10 reduction in a single district of Paris, France, for various methods of traffic improvement. Here we rank and evaluate improvements in non-accidental mortality for thirteen possible scenarios to reduce traffic related PM10 emissions. RESULTS: The maximum impact scenario requires all passenger vehicles to meet Euro 5 standards and excludes diesel vehicles, resulting in long-term decreases in non-accidental mortality of 148.79 people per year, or 104.40 per 100,000 people. Similar reductions hold for the scenario requiring a completely electric passenger fleet, with long-term annual reductions of 137.14 premature mortalities. Removing all diesel vehicles is the third most impactful scenario, preventing 135.55 deaths yearly. DISCUSSION: PARTLESS provides comparisons between thirteen different traffic-related air quality reduction mechanisms in terms of improvements in mortality rates. Improving emissions standards, increasing electric vehicle use and removing diesel vehicles can prevent more than 148 deaths per year in this district alone. Further improvements in mortality reduction may require changes to the composition of vehicle components, asphalt or to the management of resuspended particulate matter.

Weaving the molecular and cognitive strands of memory.

Several recent studies seamlessly blend cognitive, systems, and molecular neuroscience to unravel the temporal organization of memory.

Isolation and characterization of fission yeast sns mutants defective at the mitosis-to-interphase transition.

pim1-d1ts was previously identified in a visual screen for fission yeast mutants unable to complete the mitosis-to-interphase transition. pim1+ encodes the guanine nucleotide exchange factor (GEF) for the spi1 GTPase. Perturbations of this GTPase system by either mutation or overproduction of its regulatory proteins cause cells to arrest with postmitotic condensed chromosomes, an unreplicated genome, and a wide medial septum. The septation phenotype of pim1-d1ts was used as the basis for a more extensive screen for this novel class of sns (septated, not in S-phase) mutants. Seventeen mutants representing 14 complementation groups were isolated. Three strains, sns-A3, sns-A5, and sns-A6, representing two different alleles, are mutated in the pim1+ gene. Of the 13 non-pim1ts sns complementation groups, 11 showed genetic interactions with the spi1 GTPase system. The genes mutated in 10 sns strains were synthetically lethal with pim1-d1, and six sns strains were hypersensitive to overexpression of one or more of the known components of the spil GTPase system. Epistasis analysis places the action of the genes mutated in nine of these strains downstream of pim1+ and the action of one gene upstream of pim1+. Three strains, sns-A2, sns-B1, and sns-B9, showed genetic interaction with the spil GTPase system in every test performed. sns-B1 and sns-B9 are likely to identify downstream targets, whereas sns-A2 is likely to identify upstream regulators of the spi1 GTPase system that are required for the mitosis-to-interphase transition.

Perturbations in the spi1p GTPase cycle of Schizosaccharomyces pombe through its GTPase-activating protein and guanine nucleotide exchange factor components result in similar phenotypic consequences.

spi1p of Schizosaccharomyces pombe is a structural homolog of the mammalian GTPase Ran. The distribution between the GTP- and GDP-bound forms of the protein is regulated by evolutionarily conserved gene products, rna1p and pim1p, functioning as GTPase-activating protein (GAP) and guanine nucleotide exchange factor (GEF), respectively. Antibodies to spi1p, pim1p, and rna1p were generated and used to demonstrate that pim1p is exclusively nuclear, while rna1p is cytoplasmic. A loss of pim1p GEF activity or an increase in the rna1p GAP activity correlates with a change in the localization of the GTPase from predominantly nuclear to uniformly distributed, suggesting that the two forms are topologically segregated and that the nucleotide-bound state of spi1p may dictate its intracellular localization. We demonstrate that the phenotype of cells overproducing the GAP resembles the previously reported phenotype of mutants with alterations in the GEF: the cells are arrested in the cell cycle as septated, binucleated cells with highly condensed chromatin, fragmented nuclear envelopes, and abnormally wide septa. Consistent with the expectation that either an increased dosage of the GAP or a mutation in the GEF would lead to an increase of the spi1p-GDP/spi1p-GTP ratio relative to that of wild-type cells, overexpression of the GAP together with a mutation in the GEF is synthetically lethal. The similar phenotypic consequences of altering the functioning of the nuclear GEF or the cytoplasmic GAP suggest that there is a single pool of the spi1p GTPase that shuttles between the nucleus and the cytoplasm. Phenotypically, rna1 null mutants, in which spi1p-GTP would be expected to accumulate, resemble pim1(ts) and rna1p-overproducing cells, in which spi1p-GDP would be expected to accumulate. Taken together, these results support the hypothesis that the balance between the GDP- and GTP-bound forms of spi1p mediates the host of nuclear processes that are adversely affected when the functioning of different components of this system is perturbed in various organisms.

Ran-binding protein-1 is an essential component of the Ran/RCC1 molecular switch system in budding yeast.

We have performed a screen for genes that affect chromosome stability when overexpressed in the budding yeast Saccharomyces cerevisiae. Two of the genes recovered in the screen, CST17 and CST20, share a number of phenotypic properties, suggesting their involvement in the same cellular process. DNA sequence analysis of these genes revealed that they encode components of the Ran/RCC1 molecular switch system: CST17 is Ran itself (Ras-like nuclear protein) and CST20 is a novel yeast protein with a high degree of similarity to mammalian RanBP1, which is known to interact with Ran-GTP in vitro. We demonstrate that the CST20 protein can interact with Ran-GTP in vitro under similar conditions, indicating that it is the functional yeast homolog of mammalian RanBP1. The results of immunoprecipitation experiments show that the two yeast proteins form a complex in vivo. Deletion of the gene encoding RanBP1 revealed that it is essential for viability, as are Ran and RCC1. Similar phenotypic consequences of overproduction of either Ran or RanBP1 indicate that the latter protein is a functional component of the Ran/RCC1 molecular switch system, which is implicated in the control of a number of nuclear functions. Our finding that overproduction of two components of this system results in mitotic chromosome nondisjunction and sensitivity to an anti-microtubule drug benomyl suggest their involvement in mitosis as well. Thus RanBP1 is a functional component of a highly conserved molecular system that affects diverse cellular processes. The availability of this gene in S. cerevisiae provides a genetic system for the analysis of RanBP1 function in vivo.

Four novel mutations underlying mild or intermediate forms of alpha-L-iduronidase deficiency (MPS IS and MPS IH/S).

The alpha-L-iduronidase deficiency diseases (Mucopolysaccharidosis I) cover a spectrum of clinical severity ranging from the very severe (Hurler syndrome, MPS IH) through an intermediate (Hurler/Scheie syndrome, MPS IH/S) to a relatively mild form (Scheie syndrome, MPS IS). Numerous mutations of the gene encoding alpha-L-iduronidase (IDUA) are known in Hurler syndrome, but only three in the other disorders. We report on novel mutations of the IDUA gene in one patient with the Scheie syndrome and in three patients with the Hurler/Scheie syndrome. The novel mutations, all single base changes, encoded the substitutions R492P (Scheie), and X654G, P496L, and L490P (Hurler/Scheie). The L490P mutation was apparently homozygous, whereas each of the others was found in compound heterozygosity with a Hurler mutation. The deleterious nature of the mutations was confirmed by absence of enzyme activity upon transfection of the corresponding mutagenized cDNAs into Cos-1 cells. These results provide additional information for genotype-phenotype correlations.

Overexpression of the human lysosomal enzyme alpha-L-iduronidase in Chinese hamster ovary cells.

We developed a Chinese hamster ovary (CHO) cell line that produces and secretes large quantities of recombinant human alpha-L-iduronidase, the lysosomal hydrolase deficient in mucopolysaccharidosis I (Hurler, Hurler-Scheie, and Scheie syndromes). The alpha-L-iduronidase cDNA was introduced into a vector containing the cytomegalovirus immediate early gene promoter/enhancer, a murine immunoglobulin C alpha region intron, and the bovine growth hormone polyadenylation signal. Following cotransfection with a plasmid containing the neomycin resistance gene, stably transfected lines were selected with G-418. The highest expressing CHO cell line contained 1400-6000 units of alpha-L-iduronidase per milligram of protein, or 0.6-2.4% of total cell protein. Secreted alpha-L-iduronidase was 3000- to 7000 fold increased, with about 5000 units accumulating in 24 h per 10(7) cells. The activity and distribution of five other lysosomal glycosidases were not significantly affected. Metabolic labeling showed that half of the newly synthesized alpha-L-iduronidase was secreted, but generally less was recovered due to its instability in the medium. It was post-translationally processed as previously shown for alpha-L-iduronidase of human fibroblasts. Recombinant alpha-L-iduronidase was efficiently endocytosed by Hurler fibroblasts utilizing a mannose 6-phosphate-dependent mechanism (half maximal uptake at 0.7 nM) and was "corrective" for abnormal glycosaminoglycan accumulation (half-maximal correction at 0.7 pM). The half-life of the recombinant enzyme was 5 days following uptake into Hurler fibroblasts. Production in a 5-liter microcarrier culture system permitted the collection of 15 mg or more per day.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular analysis of Hurler syndrome in Druze and Muslim Arab patients in Israel: multiple allelic mutations of the IDUA gene in a small geographic area.

The mutations underlying Hurler syndrome (mucopolysaccharidosis IH) in Druze and Muslim Israeli Arab patients have been characterized. Four alleles were identified, using a combination of (a) PCR amplification of reverse-transcribed RNA or genomic DNA segments, (b) cycle sequencing of PCR products, and (c) restriction-enzyme analysis. One allele has two amino acid substitutions, Gly409-->Arg in exon 9 and Ter-->Cys in exon 14. The other three alleles have mutations in exon 2 (Tyr64-->Ter), exon 7 (Gln310-->Ter), or exon 8 (Thr366-->Pro). Transfection of mutagenized cDNAs into Cos-1 cells showed that two missense mutations, Thr366-->Pro and Ter-->Cys, permitted the expression of only trace amounts of alpha-L-iduronidase activity, whereas Gly409-->Arg permitted the expression of 60% as much enzyme as did the normal cDNA. The nonsense mutations were associated with abnormalities of RNA processing: (1) both a very low level of mRNA and skipping of exon 2 for Tyr64-->Ter and (2) utilization of a cryptic splice site for Gln310-->Ter. In all instances, the probands were found homozygous, and the parents heterozygous, for the mutant alleles, as anticipated from the consanguinity in each family. The two-mutation allele was identified in a family from Gaza; the other three alleles were found in seven families, five of them Druze, residing in a very small area of northern Israel. Since such clustering suggests a classic founder effect, the presence of three mutant alleles of the IDUA gene was unexpected.