136 research outputs found

    Molecular analyses of gut contents: elucidating the feeding of co-occurring salps in the Lazarev Sea from a different perspective

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    The diet of Antarctic salps was elucidated by investigating their gut content using “Automated Ribosomal Intergenic Spacer Analysis” and 454-pyrosequencing. Salp samples were collected during the Lazarev Krill Study in the Western Weddell Sea (summer 2005/06 and 2007/08, fall 2004, and winter 2006). Two salp species, Salpa thompsoni and Ihlea racovitzai, both occur in the Southern Ocean, can overlap geographically and seasonally. Here we provide evidence that despite the non-selective feeding mechanism, the two co-occuring salp species might have different niches within one given habitat. ARISA-patterns of 93 salp gut content samples revealed strong differences between the two salp species, even at the same sampling site. These differences were confirmed by 454-pyrosequencing of the V4-18S rDNA of ten salps. The pyrosequencing data indicate that flagellates, in particular dinophyceae constitute a high proportion of the sequence reads identified in the gut content of both salp species. However, within the dinophyceae differences in the read composition were detected between the two salp species. This supports the findings of a previous study where fatty acid signatures indicate a flagellate based diet of salps, even though microscopic analyses identified diatoms as the dominant component of salp gut contents

    Ice-tethered platforms & ROV, Progress report 2018

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    Progress report on the work of FRAM Task 3.1 for the bi-annual FRAM workshop

    Dosimetric comparison of protons vs photons in re-irradiation of intracranial meningioma

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    Objectives: Re-irradiation of recurrent intracranial meningiomas represents a major challenge due to dose limits of critical structures and the necessity of sufficient dose coverage of the recurrent tumor for local control. The aim of this study was to investigate dosimetric differences between pencil beam scanning protons (PBS) and volumetric modulated arc therapy (VMAT) photons for intracranial re-irradiation of meningiomas. Methods: Nine patients who received an initial dose &gt;50 Gy for intracranial meningioma and who were re-irradiated for recurrence were selected for plan comparison. A volumetric modulated arc therapy photon and a pencil beam scanning proton plan were generated (prescription dose: 15 × 3 Gy) based on the targets used in the re-irradiation treatment. Results: In all cases, where the cumulative dose exceeded 100 or 90 Gy, these high dose volumes were larger for the proton plans. The integral doses were significantly higher in all photon plans (reduction with protons: 48.6%, p &lt; 0.01). In two cases (22.2%), organ at risk (OAR) sparing was superior with the proton plan. In one case (11.1%), the photon plan showed a dosimetric advantage. In the remaining six cases (66.7%), we found no clinically relevant differences in dose to the OARs. Conclusions: The dosimetric results of the accumulated dose for a re-irradiation with protons and with photons were very similar. The photon plans had a steeper dose falloff directly outside the target and were superior in minimizing the high dose volumes. The proton plans achieved a lower integral dose. Clinically relevant OAR sparing was extremely case specific. The optimal treatment modality should be assessed individually. Advances in knowledge: Dose sparing in re-irradiation of intracranial meningiomas with protons or photons is highly case specific and the optimal treatment modality needs to be assessed on an individual basis. </jats:sec

    Efficacy and safety analysis in metastatic cancer patients treated with multiple courses of repeat radiation therapy

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    BACKGROUND AND PURPOSE: Due to advances in oncology, a growing proportion of patients is treated with repetitive courses of radiotherapy. The aim of this study is to analyze whether radiotherapy maintains its safety and efficacy profile in patients treated with multiple repeat courses of irradiation. MATERIAL AND METHODS: All patients treated between 2011 and 2019 at our institution were screened for a minimum of five repeat irradiation courses, to analyze treatment characteristics, survival, safety and efficacy. The type of re-irradiation was classified according to ESTRO-EORTC consensus guidelines. RESULTS: A total of n = 112 patients receiving n = 660 radiotherapy courses were included in this retrospective cohort study. The most frequent primary tumors were lung cancer in 41.9 % (n = 47) and malignant melanoma in 8.9 % (n = 10). The most frequent re-irradiation types were repeat irradiation and Type 2 re-irradiation in 309 (46.8 %) and 113 (17.1 %) cases, respectively. Median survival after the first course of radiotherapy was 3.6 (0.3-13.4) years. Response to radiotherapy was observed in 548 (83.0 %) cases and CTCAE toxicity grade ≥ 3 was observed in 21 (3.2 %) cases. An increasing number of RT courses (HR: 1.30, p=<0.0001), Type 1 re-irradiation (HR 3.50, p = 0.008) and KPS ≤ 80 % (HR: 2.02, p = 0.002) were associated with significantly worse treatment responses. Toxicity rates remained stable with increasing numbers of RT courses. CONCLUSION: Multiple courses of repeat radiotherapy maintain a favorable therapeutic ratio of high response combined with reasonable safety profile

    Seminal and nodal roots of barley differ in anatomy, proteome and nitrate uptake capacity

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    The root system of barley plants is composed of embryogenic, seminal roots as well as lateral and nodal roots that are formed postembryonically from seminal roots and from the basal part of shoots, respectively. Due to their distinct developmental origin, seminal and nodal roots may differ in function during plant development; however, a clear comparison between these two root types has not yet been undertaken. In this study, anatomical, proteomic and physiological traits were compared between seminal and nodal roots of similar developmental stages. Nodal roots have larger diameter, larger metaxylem area and a larger number of metaxylem vessels than seminal roots. Proteome profiling uncovered a set of root-type-specific proteins, including proteins related to the cell wall and cytoskeleton organization, which could potentially be implicated with differential metaxylem development. We also found that nodal roots have higher levels of auxin, which is known to trigger metaxylem development. At millimolar nitrate supply, nodal roots had approximately 2-fold higher nitrate uptake and root-to-shoot translocation capacities than seminal roots, whereas no differences were found at micromolar nitrate supply. Since these marked differences were not reflected by the transcript levels of low-affinity nitrate transporter genes, we hypothesize that the larger metaxylem volume of nodal roots enhances predominantly the low-affinity uptake and translocation capacities of nutrients that are transported with the bulk flow of water, like nitrate

    Patterns of metastatic spread and tumor burden in unselected cancer patients using PET imaging: Implications for the oligometastatic spectrum theory

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    INTRODUCTION AND BACKGROUND: Metastatic disease has been proposed as a continuum, with no clear cut-off between oligometastatic and polymetastatic disease. This study aims to quantify tumor burden and patterns of spread in unselected metastatic cancer patients referred for PET-based staging, response assessment of restaging. MATERIALS AND METHODS: All oncological fluorodeoxyglucose (FDG-) and prostate-specific membrane antigen (PSMA-) positron emission tomography (PET) scans conducted at a single academic center in 2020 were analyzed. Imaging reports of all patients with metastatic disease were reviewed and assessed. RESULTS: For this study, 7,000 PET scans were screened. One third of PET scans (n = 1,754; 33 %) from 1,155 unique patients showed presence of metastatic disease from solid malignancies, of which 601 (52 %) and 554 (48 %) were classified as oligometastatic (maximum 5 metastases) and polymetastatic (>5 metastases), respectively. Lung and pleural cancer, skin cancer, and breast cancer were the most common primary tumor histologies with 132 (23.8 %), 88 (15.9 %), and 72 (13.0 %) cases, respectively. Analysis of the number of distant metastases showed a strong bimodal distribution of the metastatic burden with 26 % of patients having one solitary metastasis and 43 % of patients harboring >10 metastases. Yet, despite 43 % of polymetastatic patients having >10 distant metastases, their pattern of distribution was restricted to one or two organs in about two thirds of patients, and there was no association between the number of distant metastases and the number of involved organs. CONCLUSION: The majority of metastatic cancer patients are characterized by either a solitary metastasis or a high tumor burden with >10 metastases, the latter was often associated with affecting a limited number of organs. These findings support both the spectrum theory of metastasis and the seed and soil hypothesis and can support in designing the next generation of clinical trials in the field of oligometastatic disease

    Use of busulfan in conditioning for allogeneic hematopoietic stem cell transplantation in adults : a survey by the Transplant Complications Working Party of the EBMT

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    A survey was carried out among EBMT centers about the use of busulfan for conditioning in allogeneic stem cell transplantation. Of 109 responding centers, 106 used busulfan for conditioning, 102 in conventional myeloablative doses, and 93 in reduced doses (RIC). The route of administration was mostly intravenous, but similar to 10% of the centers gave the drug orally. The number of doses in i.v. administration varied and was in myeloablative conditioning mostly one (50 centers) or four (43 centers) doses a day. Seventeen of the 106 centers used pharmacokinetics for dose adjustment in myeloablative conditioning, nine in RIC. The details of pharmacokinetic monitoring varied markedly. Three quarters of the centers reported adjusting the dose based on obesity in myeloablative conditioning and about 60% in RIC. The most common method for dose calculation was ideal body weight + 0.25 x (actual body weight - ideal body weight). In conclusion, the present survey showed marked heterogeneity in the current practices of busulfan administration for conditioning. The impact of the heterogeneity is not well known. Due to this and the scarcity of support from controlled clinical studies, no clear guidelines can be presented, but some prevailing policies to be recommended were identified.Peer reviewe
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