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Selected AbstractsWhy do melanomas get so dark?EXPERIMENTAL DERMATOLOGY, Issue 11 2009Rossitza Lazova Abstract:, Cutaneous malignant melanomas often exhibit pigmented regions that are darker than the surrounding skin. While melanoma cells are the original source of the melanin, keratinocytes and melanophages also contribute to the tumor colour because they contain melanin obtained from melanoma cells. However, little is known of the origin of darkly pigmented melanoma cells or of the molecular pathways regulating their melanin production. Here we discuss observations that dark melanoma cells emerge from within populations of melanoma in situ and that, in addition to producing abundant dark pigment, they appear to be undergoing autophagy. Moreover, autophagy appears to be a common trait of invasive melanoma cells in the dermis. The underlying cause of this phenomenon may stem from aberrant production of glycosylation structures known as ,1,6-branched oligosaccharides. Our studies of dark cutaneous melanomas were prompted by analyses of experimental mouse macrophage-melanoma hybrids fused in the laboratory. Like melanoma cells in cutaneous malignant melanoma, experimental hybrids also displayed abundant dark pigment and autophagy, and had high levels of ,1,6-branched oligosaccharides. Whether or not darkly pigmented malignant melanoma cells originate from fusion with macrophages in vivo remains to be determined. In any event, pigmentation in melanoma, long considered as a secondary aspect of the malignancy, may be a visible warning that the cells have gained competence for invasion and metastasis. [source] Monitored Natural Attenuation of Manufactured Gas Plant Tar Mono- and Polycyclic Aromatic Hydrocarbons in Ground Water: A 14-Year Field StudyGROUND WATER MONITORING & REMEDIATION, Issue 3 2009Edward F. Neuhauser Site 24 was the subject of a 14-year (5110-day) study of a ground water plume created by the disposal of manufactured gas plant (MGP) tar into a shallow sandy aquifer approximately 25 years prior to the study. The ground water plume in 1988 extended from a well-defined source area to a distance of approximately 400 m down gradient. A system of monitoring wells was installed along six transects that ran perpendicular to the longitudinal axis of the plume centerline. The MGP tar source was removed from the site in 1991 and a 14-year ground water monitored natural attenuation (MNA) study commenced. The program measured the dissolved mono- and polycyclic aromatic hydrocarbons (MAHs and PAHs) periodically over time, which decreased significantly over the 14-year period. Naphthalene decreased to less than 99% of the original dissolved mass, with mass degradation rates of 0.30 per year (half-life 2.3 years). Bulk attenuation rate constants for plume centerline concentrations over time ranged from 0.33 ± 0.09 per year (half-life 2.3 ± 0.8 years) for toluene and 0.45 ± 0.06 per year (half-life 1.6 ± 0.2 years) for naphthalene. The hydrogeologic setting at Site 24, having a sandy aquifer, shallow water table, clay confining layer, and aerobic conditions, was ideal for demonstrating MNA. However, these results demonstrate that MNA is a viable remedial strategy for ground water at sites impacted by MAHs and PAHs after the original source is removed, stabilized, or contained. [source] Phenotypic Reaction and Genetic Analysis Using AFLP-derived SCARs for Resistance to Apple ScabJOURNAL OF PHYTOPATHOLOGY, Issue 5 2004E. M. Huaracha Abstract Six sequence-characterized amplified region (SCAR) markers linked to the apple scab resistance gene Vf were evaluated for their utility in marker-assisted selection (MAS) in apple breeding. Of the six SCARs used in this study, ACS-6 was located left of the Vf gene, ACS-7 and ACS-9 co-segregated with Vf, and ACS-8, ACS-4, ACS-5 were located right of the Vf gene. Three families derived from crosses between scab-resistant and scab-susceptible cultivars, including ,Liberty' × ,Deljub', ,Liberty' × ,Delcorf', and ,Florina' ×,Delcorf', previously screened for scab resistance following greenhouse inoculation with the fungal pathogen Venturia inaequalis, were genotyped and compared with phenotypic reactions to scab infection in the field. For each family, a subset progeny of 30 seedlings (propagated onto Malling 9 rootstock and of 7 years old) was selected based on fungal sporulation according to the following scheme. Ten seedlings with no visible scab sporulation on leaves were given phenotypic scores of 0 (deemed resistant); 10 seedlings with moderate scab sporulation were given phenotypic scores of 1.0 (deemed moderately resistant); and 10 seedlings with heavy sporulation were given phenotypic scores of 2.0 (deemed susceptible). DNA was isolated from leaf tissue collected from all 90 seedlings, parents and Malus floribunda 821, the original source of the Vf gene, and screened with all six SCARs. All six SCARs were present in the two scab-resistant parents, ,Liberty' and ,Florina', and M. floribunda 821; while, the two scab-susceptible parents, ,Deljub' and ,Delcorf', lacked all SCARs. All SCARs were either present or absent in varying numbers of seedlings in each progeny with phenotypic ratings of either 0 (resistant) or 1.0 (moderately resistant); while all seedlings with phenotypic ratings of 2.0 (susceptible) lacked all SCARs. The inconsistencies between phenotypic scab ratings and SCAR marker data are discussed. [source] A BRIEF INTRODUCTION TO SCALE-FREE NETWORKSNATURAL RESOURCE MODELING, Issue 1 2006WILLIAM J. REED ABSTRACT. This article provides a brief introduction to scale-free networks. The notion of a scale-free network is defined and some examples given. Properties frequently exhibited by scale-free networks are discussed. The importance of the phenomenon of preferential attachment in generating scale-free networks is illustrated with two examples for the spread of a persistent disease. The models are similar in that they both yield a total infected population (1) which is geometrically distributed, and growing exponentially in expectation; and (2) in which the average distance from the original source of infection grows in a similar way over time. However one model, which has preferential attachment (infection), yields a scale-free network, while the other which has homogeneous infectivity does not. The possible application of the theory of scale-free networks to resource management is briefly discussed. [source] Microbial and clinical determinants of time-to-positivity in patients with bacteraemiaCLINICAL MICROBIOLOGY AND INFECTION, Issue 7 2007J. A. Martínez Abstract Time-to-positivity is useful in the diagnosis of catheter-related bacteraemia and as a predictor of an endovascular source in patients with Staphylococcus aureus bacteraemia. However, this parameter has been evaluated for only a limited number of microorganisms. In the present study, time-to-positivity was recorded for 1872 episodes of significant monomicrobial bacteraemia diagnosed at a teaching hospital during a 2-year period, and the associated microbial and clinical variables were investigated. According to multivariate analysis, Streptococcus pneumoniae, ,-haemolytic streptococci, Escherichia coli, Klebsiella, Enterobacter, Citrobacter and Aeromonas were characterised by fast growth, with an endovascular source, shock, liver cirrhosis and neutropenia also predicting a short time-to-positivity. For patients not receiving appropriate antibiotics, detection of Gram-positive cocci in clusters within 14 h was predictive of Staph. aureus; a time-to-positivity of >21 h ruled out the possibility that a Gram-positive organism in chains was a ,-haemolytic streptococcus or Strep. pneumoniae, and a time-to-positivity of ,12 h meant that it was very unlikely that a Gram-negative bacillus was a non-fermenter. A time-to-positivity of ,8 h was predictive of a non-urinary tract source in patients with E. coli bacteraemia, and detection of growth within 13 h predicted an endovascular source in those with Staph. aureus bacteraemia. In conclusion, time-to-positivity depended on the microorganism, original source and clinical variables involved. Although this measurement may provide some early clues concerning the microorganisms involved and the source of bacteraemia, its clinical impact remains to be defined. [source] A new instrumental precipitation dataset for the greater alpine region for the period 1800,2002INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2005Ingeborg Auer Abstract The paper describes the development of a dataset of 192 monthly precipitation series covering the greater alpine region (GAR, 4,18°E by 43,49°N). A few of the time series extend back to 1800. A description is provided of the sometimes laborious processes that were involved in this work: from locating the original sources of the data to homogenizing the records and eliminating as many of the outliers as possible. Locating the records required exhaustive searches of archives currently held in yearbooks and other sources of the states, countries and smaller regional authorities that existed at various times during the last 200 years. Homogeneity of each record was assessed by comparison with neighbouring series, although this becomes difficult when the density of stations reduces in the earliest years. An additional 47 series were used, but the density of the sites in Austria and Switzerland was reduced to maintain an even coverage in space across the whole of the GAR. We are confident of the series back to 1840, but the quality of data before this date must be considered poorer. Of all of the issues involved in homogenizing these data, perhaps the most serious problem is associated with the differences in the height above ground of the precipitation gauges, in particular the general lowering of gauge heights in the late 19th century for all countries, with the exception of Italy. The standard gauge height in the early-to-mid 19th century was 15,30 m above the ground, with gauges being generally sited on rooftops. Adjustments to some series of the order of 30,50% are necessary for compatibility with the near-ground location of gauges during much of the 20th century. Adjustments are sometimes larger in the winter, when catching snowfall presents serious problems. Data from mountain-top observatories have not been included in this compilation (because of the problem of measuring snowfall), so the highest gauge sites are at elevations of 1600,1900 m in high alpine valley locations. Two subsequent papers will analyse the dataset. The first will compare the series with other large-scale precipitation datasets for this region, and the second will describe the major modes of temporal variability of precipitation totals in different seasons and determine coherent regions of spatial variability. Copyright © 2005 Royal Meteorological Society [source] Sándor, Gizella, Elma: A biographical journey,THE INTERNATIONAL JOURNAL OF PSYCHOANALYSIS, Issue 2 2004Emanuel Berman In recent years, particularly with the publication of the Freud-Ferenczi correspondence, it has become clear that the rich theoretical dialogue between Freud and Ferenczi, a dialogue that may be seen as constitutive for psychoanalytic discourse in recent decades, was intensely intertwined with their complex personal relationship. Two women-Gizella Pálos, who eventually became Ferenczi's wife, and her daughter Elma, who was both Ferenczi's and Freud's analysand, and with whom Ferenczi fell in love-played a crucial role in shaping the Freud-Ferenczi relationship. Their own voices, however, have so far been barely heard. This paper is a preliminary report of a biographical research project which aims to complete the puzzle, by getting to know better Gizella, Elma and their family, with the help of numerous original sources, many of them unpublished till now. The emerging picture tends to confirm Ferenczi's initial view of Elma as a person of depth and integrity, rather than Freud's view of her as fundamentally disturbed; countertransference-love, it is suggested, may have facilitated fuller perception rather than clouding it. The question of the impact of Elma's ,confusion of tongues' with Ferenczi and with Freud on her subsequent life is also discussed. [source] Genetic Heterogeneity of IcelandersANNALS OF HUMAN GENETICS, Issue 1 2003E. Árnason Summary Recently statements have been made about a special ,genetic homogeneity' of the Icelanders that are at variance with earlier work on blood groups and allozymes. To validate these claims an extensive reanalysis was undertaken of mtDNA variation by examining primary data from original sources on 26 European populations. The results show that Icelanders are among the most genetically heterogeneous Europeans by the mean number of nucleotide differences as well as by estimates of , parameters of the neutral theory. The distribution of pairwise differences in general has the same shape as European populations and shows no evidence of bottlenecks of numbers in Iceland. The allelic frequency distribution of Iceland is relatively even with a large number of haplotypes at polymorphic frequencies contrasting with other countries. This is a signature of admixture during the founding or history of Iceland. Assumptions of models used to simulate number of haplotypes at sampling saturation for comparing populations are violated to different degrees by various countries. Anomalies identified in data in previous reports on Icelandic mtDNA variation appear to be due to errors in publicly accessible databases. This study demonstrates the importance of basing analyses on primary data so that errors are not propagated. Claims about special genetic homogeneity of Icelanders are not supported by evidence. [source] | |||||||||||||