1,542 research outputs found

    Carcinomatous Meningitis: The Natural History of Successfully Treated Metastatic Bladder Cancer

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    Carcinomatous meningitis due to bladder cancer is a rare entity reported only in case reports. Optimal therapy is thus poorly defined with earlier cases reporting an unsuccessful outcome. Here we report a case of late carcinomatous meningitis secondary to transitional cell carcinoma (TCC) of the bladder occurring in a patient in complete remission. He was successfully treated with intrathecal methotrexate and whole brain irradiation and experienced prolonged survival after treatment. With modern chemotherapy increasing complete remissions and survival rates in patients with TCC, more and more patients are being reported with carcinomatous meningitis. We raise the question of whether central nervous system prophylaxis should be considered in patients with TCC achieving a complete remission to chemotherapy in the metastatic setting

    Male Competition Reverses Female Preference For Male Chemical Cues

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    Females must choose among potential mates with different phenotypes in a variety of social contexts. Many male traits are inherent and unchanging, but others are labile to social context. Competition, for example, can cause physiological changes that reflect recent wins and losses that fluctuate throughout time. We may expect females to respond differently to males depending on the outcome of their most recent fight. In Bolitotherus cornutus (forked fungus beetles), males compete for access to females, but copulation requires female cooperation. In this study, we use behavioral trials to determine whether females use chemical cues to differentiate between males and whether the outcome of recent male competition alters female preference. We measured female association time with chemical cues of two size‐matched males both before and after male–male competition. Females in our study preferred to associate with future losers before males interacted, but changed their preference for realized winners following male competitive interactions. Our study provides the first evidence of change in female preference based solely on the outcome of male–male competition

    Comparative genomic analysis of bacteriophages specific to the channel catfish pathogen Edwardsiella ictaluri

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    <p>Abstract</p> <p>Background</p> <p>The bacterial pathogen <it>Edwardsiella ictaluri </it>is a primary cause of mortality in channel catfish raised commercially in aquaculture farms. Additional treatment and diagnostic regimes are needed for this enteric pathogen, motivating the discovery and characterization of bacteriophages specific to <it>E. ictaluri</it>.</p> <p>Results</p> <p>The genomes of three <it>Edwardsiella ictaluri</it>-specific bacteriophages isolated from geographically distant aquaculture ponds, at different times, were sequenced and analyzed. The genomes for phages eiAU, eiDWF, and eiMSLS are 42.80 kbp, 42.12 kbp, and 42.69 kbp, respectively, and are greater than 95% identical to each other at the nucleotide level. Nucleotide differences were mostly observed in non-coding regions and in structural proteins, with significant variability in the sequences of putative tail fiber proteins. The genome organization of these phages exhibit a pattern shared by other <it>Siphoviridae</it>.</p> <p>Conclusions</p> <p>These <it>E. ictaluri</it>-specific phage genomes reveal considerable conservation of genomic architecture and sequence identity, even with considerable temporal and spatial divergence in their isolation. Their genomic homogeneity is similarly observed among <it>E. ictaluri </it>bacterial isolates. The genomic analysis of these phages supports the conclusion that these are virulent phages, lacking the capacity for lysogeny or expression of virulence genes. This study contributes to our knowledge of phage genomic diversity and facilitates studies on the diagnostic and therapeutic applications of these phages.</p

    Gate voltage dependent Rashba spin splitting in hole transverse magnetic focussing

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    Magnetic focussing of charge carriers in two-dimensional systems provides a solid state version of a mass spectrometer. In the presence of a spin-orbit interaction, the first focussing peak splits into two spin dependent peaks, allowing focussing to be used to measure spin polarisation and the strength of the spin-orbit interaction. In hole systems, the k^3 dependence of the Rashba spin-orbit term allows the spatial separation of spins to be changed in-situ using a voltage applied to an overall top gate. Here we demonstrate that this can be used to control the splitting of the magnetic focussing peaks. Additionally, we compare the focussing peak splitting to that predicted by Shubnikov-de Haas oscillations and k.p bandstructure calculations. We find that the focussing peak splitting is consistently larger than expected, suggesting further work is needed on understanding spin dependent magnetic focussing

    Spin polarisation and spin dependent scattering of holes in transverse magnetic focussing

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    In 2D systems with a spin-orbit interaction, magnetic focussing can be used to create a spatial separation of particles with different spin. Here we measure hole magnetic focussing for two different magnitudes of the Rashba spin-orbit interaction. We find that when the Rashba spin-orbit magnitude is large there is significant attenuation of one of the focussing peaks, which is conventionally associated with a change in the spin polarisation. We instead show that in hole systems with a k3k^3 spin-orbit interaction, this peak suppression is due to a change in the scattering of one spin state, not a change in spin polarisation. We also show that the change in scattering length extracted from magnetic focussing is consistent with results obtained from measurements of Shubnikov-de Haas oscillations. This result suggests that scattering must be considered when relating focussing peak amplitude to spin polarisation in hole system

    Characterization, Comparative Genomics and Genome Mining for Antibiotics and Secondary Metabolite of two Actinomycetales isolates

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    Actinomycetes are ubiquitous Gram (+) bacteria commonly found to have high G+C content and best known for their metabolic by-products and novel enzymes [1]. Isolates CCMMD2014 & MRMD2014 were co-cultured from soil impacted by a rusty fire hydrant in Woods Hole, MA. The Streptomyces sp. and Curtobacterium sp. isolates were identified by marker genes for 16S rRNA, rpoB, xylose isomerase, tryptophan synthase beta chain and Cytochrome P450 monooxygenase. Both isolates showed lactic acid fermentation and urease activity. The co-isolates were separated by selective culturing with antibiotics. In addition, whole genome sequencing revealed distinct inherent metabolic pathways in each culture that allowed for mutually exclusive selective culture conditions. Assembly was done using HGAP3 with Celera8 assembler using SMRT portal [2,3]. Annotation was done using the RAST server [4], with 7540 and 3969 CDS for Streptomyces sp. and Curtobacterium sp. respectively being revealed by AMIGene and BASys [5,6]. Subsequently, antiSMASH [7], was used to predict 52 and 26 secondary metabolite biosynthetic clusters that included genes for lantipeptides, terpenes, siderophores, polyketide synthases type I and II, bacteriocin and nonribosomal peptide synthase genes for Streptomyces sp. and Curtobacterium sp. respectively. The isolates have genes of potentially beneficial traits that could help study, among others, the role of fimbrial adhesins and iron in biofilm formation and investigation on natural products

    Probing Fermi surface shifts with spin resolved transverse magnetic focussing

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    Transverse magnetic focussing is the solid state equivalent of a mass spectrometer. It is unique among 2D measurement techniques as it is able to measure a well defined section of the Fermi surface, making it possible to detect changes that would be averaged out over the whole Fermi surface. Here, we utilise this unique property to probe non-adiabatic spin dynamics and spin dependent scattering of holes. We combine spin-resolved magnetic focussing with an additional independent in-plane magnetic field and observe a change in focussing peak amplitude that is not symmetric with respect to the field direction (i.e. +BB+B_{\parallel} \neq -B_{\parallel}), and is extremely sensitive to the magnitude of the in-plane magnetic field. We show that the magnetic focussing signal is extremely sensitive to small changes in the Fermi velocity, which can be used to detect small shifts in the Fermi surface caused by an in-plane magnetic field. We also find that focussing can be used to detect the proximity between spin-split Fermi surfaces, which cause non-adiabatic spin dynamics

    Local host response following an intramammary challenge with Staphylococcus fleurettii and different strains of Staphylococcus chromogenes in dairy heifers

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    Coagulase-negative staphylococci (CNS) are a common cause of subclinical mastitis in dairy cattle. The CNS inhabit various ecological habitats, ranging between the environment and the host. In order to obtain a better insight into the host response, an experimental infection was carried out in eight healthy heifers in mid-lactation with three different CNS strains: a Staphylococcus fleurettii strain originating from sawdust bedding, an intramammary Staphylococcus chromogenes strain originating from a persistent intramammary infection (S. chromogenes IM) and a S. chromogenes strain isolated from a heifer's teat apex (S. chromogenes TA). Each heifer was inoculated in the mammary gland with 1.0 x 10(6) colony forming units of each bacterial strain (one strain per udder quarter), whereas the remaining quarter was infused with phosphate-buffered saline. Overall, the CNS evoked a mild local host response. The somatic cell count increased in all S. fleurettii-inoculated quarters, although the strain was eliminated within 12 h. The two S. chromogenes strains were shed in larger numbers for a longer period. Bacterial and somatic cell counts, as well as neutrophil responses, were higher after inoculation with S. chromogenes IM than with S. chromogenes TA. In conclusion, these results suggest that S. chromogenes might be better adapted to the mammary gland than S. fleurettii. Furthermore, not all S. chromogenes strains induce the same local host response

    Influence of soil nutrients on the presence and distribution of CPR bacteria in a long-term crop rotation experiment

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    Bacteria affiliated with the Candidate Phyla Radiation (CPR) are a hyper-diverse group of ultra-small bacteria with versatile yet sparse metabolisms. However, most insights into this group come from a surprisingly small number of environments, and recovery of CPR bacteria from soils has been hindered due to their extremely low abundance within complex microbial assemblages. In this study we enriched soil samples from 14 different soil fertility treatments for ultra-small (&lt;0.45 μm) bacteria in order to study rare soil CPR. 42 samples were sequenced, enabling the reconstruction of 27 quality CPR metagenome-assembled genomes (MAGs) further classified as Parcubacteria/Paceibacteria, Saccharibacteria/Saccharimonadia and ABY1, in addition to representative genomes from Gemmatimonadetes, Dependentiae and Chlamydae phyla. These genomes were fully annotated and used to reconstruct the CPR community across all 14 plots. Additionally, for five of these plots, the entire microbiota was reconstructed using 16S amplification, showing that specific soil CPR may form symbiotic relationships with a varied and circumstantial range of hosts. Cullars CPR had a prevalence of enzymes predicted to degrade plant-derived carbohydrates, which suggests they have a role in plant biomass degradation. Parcubacteria appear to be more apt at microfauna necromass degradation. Cullars Saccharibacteria and a Parcubacteria group were shown to carry a possible aerotolerance mechanism coupled with potential for aerobic respiration, which appear to be a unique adaptation to the oxic soil environment. Reconstruction of CPR communities across treatment plots showed that they were not impacted by changes in nutrient levels or microbiota composition, being only impacted by extreme conditions, causing some CPR to dominate the community. These findings corroborate the understanding that soil-dwelling CPR bacteria have a very broad symbiont range and have metabolic capabilities associated to soil environments which allows them to scavenge resources and form resilient communities. The contributions of these microbial dark matter species to soil ecology and plant interactions will be of significant interest in future studies
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