The Global Dam Watch database of river barrier and reservoir information for large-scale applications.

There are millions of river barriers worldwide, ranging from wooden locks to concrete dams, many of which form associated impoundments to store water in small ponds or large reservoirs. Besides their benefits, there is growing recognition of important environmental and social trade-offs related to these artificial structures. However, global datasets describing their characteristics and geographical distribution are often biased towards particular regions or specific applications, such as hydropower dams affecting fish migration, and are thus not globally consistent. Here, we present a new river barrier and reservoir database developed by the Global Dam Watch (GDW) consortium that integrates, harmonizes, and augments existing global datasets to support large-scale analyses. Data curation involved extensive quality control processes to create a single, globally consistent data repository of instream barriers and reservoirs that are co-registered to a digital river network. Version 1.0 of the GDW database contains 41,145 barrier locations and 35,295 associated reservoir polygons representing a cumulative storage capacity of 7,420 km3 and an artificial terrestrial surface water area of 304,600 km2.

FGF receptor signalling is required to maintain neural progenitors during Hensen's node progression.

Previous analyses of labelled clones of cells within the developing nervous system of the mouse have indicated that descendants are initially dispersed rostrocaudally followed by more local proliferation, which is consistent with the progressing node's contributing descendants from a resident population of progenitor cells as it advances caudally. Here we electroporated an expression vector encoding green fluorescent protein into the chicken embryo near Hensen's node to test and confirm the pattern inferred in the mouse. This provides a model in which a proliferative stem zone is maintained in the node by a localized signal; those cells that are displaced out of the stem zone go on to contribute to the growing axis. To test whether fibroblast growth factor (FGF) signalling could be involved in the maintenance of the stem zone, we co-electroporated a dominant-negative FGF receptor with a lineage marker, and found that it markedly alters the elongation of the spinal cord primordium. The results indicate that FGF receptor signalling promotes the continuous development of the posterior nervous system by maintaining presumptive neural progenitors in the region near Hensen's node. This offers a potential explanation for the mixed findings on FGF in the growth and patterning of the embryonic axis.

Low-cost biomonitoring and high-resolution, scalable models of urban metal pollution.

As the global toll on human lives and ecosystems exacted by urban pollution grows, planning tools still lack the resolution to identify priority sites where toxic pollution can be most efficiently averted at a spatial scale that matches funding and management. Here we tackle this gap by demonstrating novel scalable methods to monitor and predict urban metal pollution at high resolution (<5 m) across large areas (10,000-100,000 km2) to guide pollution reduction and stormwater management. We showcase and calibrate predictive models of Zn, Cu, and a synthetic index of pollution for the Puget Sound region of Washington State, U.S., a densely urbanized yet important ecosystem of conservation interest, and exemplify their transferability across the entire United States. We leveraged widely and freely available datasets of car traffic characteristics and land use as predictor variables and trained the models with biological monitoring data of metal concentrations in epiphytic moss from >100 trees based on new rapid and low-cost protocols introduced in this study. Our model predictions, showing that 50% of the total Cu and Zn pollution across the Puget Sound watershed is deposited over only 3.3% of the land area, will allow cities to effectively and efficiently target toxic hotspots.

Development and validation of in-situ and laboratory X-ray fluorescence (XRF) spectroscopy methods for moss biomonitoring of metal pollution.

Metals are among the pollutants of highest concern in urban areas due to their persistence, bioavailability and toxicity. High concentrations of metals threaten aquatic ecosystem functioning and biodiversity, as well as human health. High-resolution estimates of pollutant sources are required to mitigate exposure to toxic compounds by identifying the specific locations and associated site characteristics where the deposition of metals is greatest. Mosses have been widely used as low-cost biological monitors of metal pollution for decades, because they readily accumulate pollutants over time, reflecting long term pollution levels. However, spectroscopic techniques to determine the concentration of metal pollutants in moss samples still require expensive instrumentation and involve time consuming sample preparation protocols with heavy use of reagents. Here we present protocols to perform in-situ and laboratory X-ray fluorescence (XRF) spectroscopy of epiphytic moss as rapid, low-cost, and accurate alternatives to conventional metal pollution biomonitoring. We also report on a preliminary validation of the measurements using mass fractions determined by inductively coupled plasma atomic emission spectroscopy (ICP-OES) as reference.•XRF measurements are taken from moss directly on tree trunks in less than five minutes.•Grinding and pelletizing of moss enables definitive quantitation (R2>0.90) of metals through portable XRF.

A Chinese hamster ovary cell mutant with a heat-sensitive, conditional-lethal defect in vacuolar function.

We describe a mutant derived from Chinese hamster ovary cells that is offt-sensitive for viability and for resistance to certain protein toxins. This mutant, termed G.7.1, grows normally at 34 degrees C but does not grow in Dulbecco's modified Eagle's medium at 39.5 degrees C. However, when this medium is supplemented with FeSO4, the mutant cells will grow at the elevated temperature. At 39.5 degrees C, G.7.1 cells acquire resistance to diphtheria toxin, modeccin, and Pseudomonas aeruginosa exotoxin A, all of which are protein toxins that require endocytosis and exposure to a low pH within vesicles before they can invade the cytosol and kill cells. The properties of mutant G.7.1 could result from a heat-sensitive lesion that impairs vacuolar acidification. We assayed the ATP-stimulated generation of pH gradients across the membrane of vesicles in cell-free preparations from mutant and parental cells by the partitioning of acridine orange into acidic compartments and found that the acidification response of the mutant cells was heat-labile. Altogether the evidence suggests that G.7.1 cells contain a heat-sensitive lesion that impairs vacuolar acidification and that they fail to grow in normal medium at 39.5 degrees C because they cannot extract Fe+3 from transferrin, a process that normally requires exposing transferrin to a low pH within endosomal vesicles.

Safety monitoring of drugs granted exclusivity under the Best Pharmaceuticals for Children Act: what the FDA has learned.

The Best Pharmaceuticals for Children Act (BPCA) was signed into law on 4 January 2002, shortly after the pediatric exclusivity provision of the Food and Drug Administration (FDA) Modernization Act expired on 1 January 2002. This Act provides six months of marketing exclusivity for a drug when a pharmaceutical company studies that drug for use in the pediatric population as requested by the FDA. Section 17 of the BPCA specifically requires that the FDA review all adverse events reported for drugs that receive pediatric exclusivity. In most of the cases, no unexpected adverse events were reported in the pediatric population; however, in some cases, this focused safety review provided information important to the safety of medication use in children.

Stability of self-esteem as a moderator of the relation between level of self-esteem and depression.

The hypothesis that stability of self-esteem would moderate the predictive relationship between level of self-esteem and depression was tested. Specifically, level of self-esteem was hypothesized to relate more strongly to subsequent depression for individuals with stable self-esteem than for individuals with unstable self-esteem. Results strongly supported this hypothesis. Implications for the relation between level of self-esteem and depression, and for the moderator variable approach to personality and prediction, are discussed.

Building the 'best service organization anywhere'. Interview by Lynn D. Kahn.

Larry L. Mathis has spent his health-care career with The Methodist Hospital System, Houston, serving since 1983 as president and chief executive officer. The network of managed, owned and affiliated hospitals has 10,000 beds and annual revenues approaching $650 million. At the hub of the system is The Methodist Hospital, a 1,218-bed tertiary-care and research facility. When it adds 300 beds later this year, the hospital will be the world's largest private hospital. In an interview with Lynn D. Kahn, Health Care Strategic Management's managing editor, Mathis describes the planning process that keeps his complex hospital system on track.

Key role played by RhoA in the balance between planar and apico-basal cell divisions in the chick neuroepithelium.

The cell division axis determines the position of daughter cells and is therefore critical for cell fate. During vertebrate neurogenesis, most cell divisions take place within the plane of the neuroepithelium (Das, T., Payer, B., Cayouette, M., and Harris, W.A. (2003). In vivo time-lapse imaging of cell divisions during neurogenesis in the developing zebrafish retina. Neuron 37, 597-609. Haydar, T.F., Ang, E., Jr., and Rakic, P. (2003). Mitotic spindle rotation and mode of cell division in the developing telencephalon. Proc Natl Acad Sci U S A 100, 2890-5. Kosodo, Y., Roper, K., Haubensak, W., Marzesco, A. M., Corbeil, D., and Huttner, W. B. (2004). Asymmetric distribution of the apical plasma membrane during neurogenic divisions of mammalian neuroepithelial cells. EMBO J. 23, 2314-24). The cellular constraints responsible for this preferential orientation are poorly understood. Combining electroporation and time-lapse confocal imaging of chick neural progenitors, the events responsible for positioning the mitotic spindle and their dependence on RhoA were investigated. The results indicate that the spindle forms with a random orientation. However, the final orientation of cell divisions is dependent on two main factors: (i) an early rotation of the spindle that aligns it within the plane of the neuroepithelium, and (ii) a specific limitation of spindle oscillations, despite free rotation around the apico-basal axis. Expressing a dominant-negative RhoA leads to apico-basal cell divisions after a correct initial rotation of the spindle. Our data reveal a specific role for RhoA in the maintenance of spindle orientation, prior to anaphase. Thus, RhoA could be a key player potentially regulated by the neurogenic program or by the neural stem cell environment to control the balance between planar and apico-basal divisions, during normal or pathological development.

Haemophilus influenzae and Neisseria gonorrhoeae recognize different specificity determinants in the DNA uptake step of genetic transformation.

Cross-transformation and quantitative competition experiments showed that Neisseria gonorrhoeae and Haemophilus influenzae do not interact with each other's DNA in transformation. These organisms must interact with different recognition sequences during DNA uptake.

Different clonal dispersion in the rostral and caudal mouse central nervous system.

We have performed a systematic clonal analysis to describe the modes of growth, dispersion and production of cells during the development of the mouse neural system. We have used mice expressing a LaacZ reporter gene under the control of the neuron specific enolase promoter to randomly generate LacZ clones in the central nervous system (CNS). We present evidence for (1) a pool of CNS founder cells that is not regionalized, i.e. give descendants dispersed along the entire A-P axis, (2) an early separation between pools of precursors for the anterior and posterior CNS and (3) distinct modes of production of progenitors in these two domains. More specifically, cell growth and dispersion of the progenitors follow a relatively coherent pattern throughout the anterior CNS, a mode that leads to a progressive regionalization of cell fates. In contrast, cell growth of progenitors of the SC appears to involve self-renewing stem cells that progress caudally during regression of the mode. Therefore, at least part of the area surrounding the node is composed of precursors with self-renewing properties and the development of the trunk is dependent on pools of stem cells regressing from A to P. Taken together with our analysis of the cell growth changes associated with neuromere formation (Mathis, L., Sieur, J., Voiculescu, O., Charnay, P. and Nicolas, J. F. (1999) Development 126, 4095-4106), our results suggest that major transitions in CNS development correspond to changes in cell behavior and may provide a link between morphogenesis and genetic patterning mechanisms (i.e. formation of the body plan).

Clonal organization in the postnatal mouse central nervous system is prefigured in the embryonic neuroepithelium.

We have used the LaacZ clonal method of cell labeling of neuronal ancestors and report that the spatial organization of neuronal cells in the post-natal CNS shares striking similarities to that in the embryonic neuroepithelium, from the spinal cord to the diencephalon. The maintenance of the organization occurs despite massive cell divisions and morphogenetic movements. We deduce that the cellular and architectural organization in the mouse CNS results from a succession of patterns of oriented cell dispersion, a general arrest of cell dispersion in the neuroepithelium, and then well-documented radial neuronal migration. The arrest of cell dispersion in the neuroepithelium is consistent with the possibility that an important part of the cellular and architectural organization of the mature CNS requires conservation of spatial relationship between cells and supports the hypothesis of a transition from global and sparse to local and dense cell interactions occurring early within the neuroepithelium.

On the role of pili in transformation of Neisseria gonorrhoeae.

Transformation of competent transformable Neisseria gonorrhoeae F62 to streptomycin resistance was unaffected by antibodies directed against the pilus protein (pilin) of this organism. The pilin component of either crude or purified pilus preparations, separated by SDS gel electrophoresis and transferred to nitrocellulose, failed to bind detectable amounts of DNA; DNA binding to other gonococcal polypeptides was observed under these conditions. These results suggest that gonococcal pilin does not play a direct role in gonococcal transformation.

Evidence in the mouse for self-renewing stem cells in the formation of a segmented longitudinal structure, the myotome.

A novel method of clonal analysis has been used in the mouse to define the cellular events that lead to the formation of a segmented longitudinal structure, the myotome. Progenitor cells of the myotome were randomly marked during development by intragenic homologous recombination in transgenic mice expressing a reporter laacZ gene. 153 clones corresponding to 7829 cells, that is 20% of the myotomal population of one embryo, were obtained from 3000 E11.5 embryos. Their analysis leads to the hypothesis that, at E11.5, the 41 segments of the myotome have been mainly produced from a unique, spatially organised pool of self-renewing stem cells that accompanies the formation of the anterior-posterior axis.

Retrospective clonal analysis of the cerebellum using genetic laacZ/lacZ mouse mosaics.

Analysis of lacZ neuronal clones in the mouse cerebellum demonstrates genealogical independence of the primary and secondary germinal epithelia (PGE and SGE) from early development. PGE precursors and their neuronal descendants are organised into two polyclonal groups of similar sizes that exhibit parasagittal patterning and generally respect the midline. The relationship between these two groups cannot be traced back in time to less than 80 independent cells, which were probably recruited following a period of non-coherent growth that distributes unrelated cells into distinct territories of the neural tube. A lateromedial clonal organisation is observed in the mature cerebellum, suggesting the existence of many small parasagittal domains of clonal restriction and/or of cell dispersion in the rostrocaudal but not in the mediolateral dimension. The organisation is orthogonal with respect to the cellular organisation in the neural tube as is the genetic organisation. Cellular and genetic patterning of the cerebellum therefore share similarities. A possible hypothesis is that distinct cell behaviours create the different clonal domains observed in this study and that the cellular and genetic organisation of the cerebellum are coordinated.

Successive patterns of clonal cell dispersion in relation to neuromeric subdivision in the mouse neuroepithelium.

We made use of the laacz procedure of single-cell labelling to visualize clones labelled before neuromere formation, in 12.5-day mouse embryos. This allowed us to deduce two successive phases of cell dispersion in the formation of the rhombencephalon: an initial anterior-posterior (AP) cell dispersion, followed by an asymmetrical dorsoventral (DV) cell distribution during which AP cell dispersion occurs in territories smaller than one rhombomere. We conclude that the general arrest of AP cell dispersion precedes the onset of morphological segmentation and is not imposed by the interface between adjacent rhombomeres. This demonstrates a major change in the mode of epithelial growth that precedes or accompanies the formation of neuromeres. We also deduced that the period of DV cell dispersion in the neuroepithelium is followed by a coherent growth phase. These results suggest a cell organization on a Cartesian grid, the coordinates of which correspond to the AP and DV axis of the neural tube. A similar sequence of AP cell dispersion followed by an arrest of AP cell dispersion, a preferential DV cell dispersion and then by a coherent neuroepithelial growth, is also observed in the spinal cord and mesencephalon. This demonstrates that a similar cascade of cell events occurs in these different domains of the CNS. In the prosencephalon, differences in spatial constraints may explain the variability in the orientation of cell clusters. Genetic and clonal patterning in the AP and DV dimensions follow the same spatial sequence. An interesting possibility is that these successive patterns of cell growth facilitate the acquisition of positional information.

Prevalence of psychopathology in carpal tunnel syndrome patients.

This study assessed the prevalence rates of psychopathology in acute carpal tunnel syndrome (CTS) and acute low back pain (LBP) patients. Psychopathology was assessed with the Structured Clinical Interview for the DSM-III-R (SCID). The results showed that the CTS patients had significantly higher rates of anxiety disorders, both current and lifetime, than the LBP patients. However, LBP patients had significantly higher rates of lifetime substance abuse than the CTS patients. In regard to other types of psychopathology, such as depression, current substance abuse, and somatoform pain disorders, CTS patients had similar rates as the LBP patients. It was concluded that anxiety disorders may be a concomitant of carpal tunnel syndrome, and that treating psychological problems along with physical aspects of the syndrome may increase the patient's chance of a successful therapeutic outcome.