218 research outputs found

    FACKEL is a sterol C-14 reductase required for organized cell division and expansion in Arabidopsis embryogenesis

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    In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. We report that FK is required for cell division and expansion and is involved in proper organization of the embryo. We isolated FK by positional cloning. Expression analysis in embryos revealed that FK mRNA becomes localized to meristematic zones. FK encodes a predicted integral membrane protein related to the vertebrate lamin B receptor and sterol reductases across species, including yeast sterol C-14 reductase ERG24. We provide functional evidence that FK encodes a sterol C-14 reductase by complementation of erg24. GC/MS analysis confirmed that fk mutations lead to accumulation of intermediates in the biosynthetic pathway preceding the C-14 reductase step. Although fk represents a sterol biosynthetic mutant, the phenotype was not rescued by feeding with brassinosteroids (BRs), the only plant sterol signaling molecules known so far. We propose that synthesis of sterol signals in addition to BRs is important in mediating regulated cell growth and organization during embryonic development. Our results indicate a novel role for sterols in the embryogenesis of plants

    Fertility Ideals of Women and Men Across the Life Course

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    This paper explores the stability of women’s and men’s fertility preferences across the life course. The data come from the first six waves of the German Family Panel (pairfam), which span the period from 2008/2009 until 2013/2014. In our analysis, fertility preferences are measured using the following question: “Under ideal circumstances, how many children would you like to have?” The average number cited by both women and men is 2.2. With rising age, this number declines modestly. Relying on fixed-effects modelling, we find that neither partnership status nor economic circumstances have any causal effect on fertility preferences. However, as the number of children a respondent has increases, his or her ideal number of children is also likely to grow. Thus, fertility ideals appear to undergo changes over time, and are adjusted in line with the size of the respondent’s own family

    3D-conformal-intensity modulated radiotherapy with compensators for head and neck cancer: clinical results of normal tissue sparing

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    BACKGROUND: To investigate the potential of parotic gland sparing of intensity modulated radiotherapy (3D-c-IMRT) performed with metallic compensators for head and neck cancer in a clinical series by analysis of dose distributions and clinical measures. MATERIALS AND METHODS: 39 patients with squamous cell cancer of the head and neck irradiated using 3D-c-IMRT were evaluable for dose distribution within PTVs and at one parotid gland and 38 patients for toxicity analysis. 10 patients were treated primarily, 29 postoperatively, 19 received concomittant cis-platin based chemotherapy, 20 3D-c-IMRT alone. Initially the dose distribution was calculated with Helax (¼ )and photon fluence was modulated using metallic compensators made of tin-granulate (n = 22). Later the dose distribution was calculated with KonRad (¼ )and fluence was modified by MCP 96 alloy compensators (n = 17). Gross tumor/tumor bed (PTV 1) was irradiated up to 60–70 Gy, [5 fractions/week, single fraction dose: 2.0–2.2 (simultaneously integrated boost)], adjuvantly irradiated bilateral cervical lymph nodes (PTV 2) with 48–54 Gy [single dose: 1.5–1.8]). Toxicity was scored according the RTOG scale and patient-reported xerostomia questionnaire (XQ). RESULTS: Mean of the median doses at the parotid glands to be spared was 25.9 (16.3–46.8) Gy, for tin graulate 26 Gy, for MCP alloy 24.2 Gy. Tin-granulate compensators resulted in a median parotid dose above 26 Gy in 10/22, MCP 96 alloy in 0/17 patients. Following acute toxicities were seen (°0–2/3): xerostomia: 87%/13%, dysphagia: 84%/16%, mucositis: 89%/11%, dermatitis: 100%/0%. No grade 4 reaction was encountered. During therapy the XQ forms showed °0–2/3): 88%/12%. 6 months postRT chronic xerostomia °0–2/3 was observed in 85%/15% of patients, none with °4 xerostomia. CONCLUSION: 3D-c-IMRT using metallic compensators along with inverse calculation algorithm achieves sufficient parotid gland sparing in virtually all advanced head and neck cancers. Since the concept of lower single (and total) doses in the adjuvantly treated volumes reduces acute morbidity 3D-c-IMRT nicely meets demands of concurrent chemotherapy protocols

    Effects of conjugated linoleic acid on myogenic and inflammatory responses in a human primary muscle and tumor coculture model

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    The antiproliferative and anti-inflammatory properties of conjugated linoleic acid (CLA) make it a potentially novel treatment in chronic inflammatory muscle wasting disease, particularly cancer cachexia. Human primary muscle cells were grown in coculture with MIA PaCa-2 pancreatic tumor cells and exposed to varying concentrations of c9,t11 and t10,c12 CLA. Expression of myogenic (Myf5, MyoD, myogenin, and myostatin) and inflammatory genes (CCL-2, COX-2, IL-8, and TNF-) were measured by real-time PCR. The t10,c12 CLA isomer, but not the c9,t11 isomer, significantly decreased MIA PaCa-2 proliferation by between 15% and 19%. There was a marked decrease in muscle MyoD and myogenin expression (78% and 62%, respectively), but no change in either Myf5 or myostatin, in myotubes grown in coculture with MIA PaCa-2 cells. CLA had limited influence on these responses. A similar pattern of myogenic gene expression changes was observed in myotubes treated with TNF- alone. Several-fold significant increases in CCL-2, COX-2, IL-8, and TNF- expression in myotubes were observed with MIA PaCa-2 coculture. The c9,t11 CLA isomer significantly decreased basal expression of TNF- in myotubes and could ameliorate its tumor-induced rise. The study provides insight into the anti-inflammatory and antiproliferative actions of CLA and its application as a therapeutic agent in inflammatory disease states.<br /

    Deformation Aware Augmented Reality for Craniotomy using 3D/2D Non-rigid Registration of Cortical Vessels

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    International audienceIntra-operative brain shift is a well-known phenomenon that describes non-rigid deformation of brain tissues due to gravity and loss of cerebrospinal fluid among other phenomena. This has a negative influence on surgical outcome that is often based on pre-operative planning where the brain shift is not considered. We present a novel brain-shift aware Augmented Reality method to align pre-operative 3D data onto the deformed brain surface viewed through a surgical microscope. We formulate our non-rigid registration as a Shape-from-Template problem. A pre-operative 3D wire-like deformable model is registered onto a single 2D image of the cortical vessels, which is automatically segmented. This 3D/2D registration drives the underlying brain structures, such as tumors, and compensates for the brain shift in sub-cortical regions. We evaluated our approach on simulated and real data composed of 6 patients. It achieved good quantitative and qualitative results making it suitable for neurosurgical guidance

    Foraminiferal assemblages as palaeoenvironmental bioindicators in Late Jurassic epicontinental platforms: relation with trophic conditions

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    Foraminiferal assemblages from the neritic environment reveal the palaeoecological impact of nutrient types in relation to shore distance and sedimentary setting. Comparatively proximal siliciclastic settings from the Boreal Domain (Brora section, Eastern Scotland) were dominated by inner−shelf primary production in the water column or in sea bottom, while in relatively seawards mixed carbonate−siliciclastic settings from the Western Tethys (Prebetic, Southern Spain), nutrients mainly derived from the inner−shelf source. In both settings, benthic foraminiferal assemblages increased in diversity and proportion of epifauna from eutrophic to oligotrophic conditions. The proximal setting example (Brora Brick Clay Mb.) corresponds to Callovian offshore shelf deposits with a high primary productivity, bottom accumulation of organic matter, and a reduced sedimentation rate for siliciclastics. Eutrophic conditions favoured some infaunal foraminifera. Lately, inner shelf to shoreface transition areas (Fascally Siltstone Mb.), show higher sedimentation rates and turbidity, reducing euphotic−zone range depths and primary production, and then deposits with a lower organic matter content (high−mesotrophic conditions). This determined less agglutinated infaunal foraminifera content and increasing calcitic and aragonitic epifauna, and calcitic opportunists (i.e., Lenticulina). The comparatively distal setting of the Oxfordian example (Prebetic) corresponds to: (i) outer−shelf areas with lower nutrient input (relative oligotrophy) and organic matter accumulation on comparatively firmer substrates (lumpy lithofacies group) showing dominance of calcitic epifaunal foraminifera, and (ii) mid−shelf areas with a higher sedimentation rate and nutrient influx (low−mesotrophic conditions) favouring potentially deep infaunal foraminifers in comparatively unconsolidated and nutrient−rich substrates controlled by instable redox boundary (marl−limestone rhythmite lithofacies).This research was carried out with the financial support of projects CGL2005−06636−C0201 and CGL2005−01316/BTE, and University of Oslo, Norway−Statoil cooperation. M.R. holds a Juan de la Cierva grant from the Ministry of Science and Technology of Spain

    Mesozoic biostratigraphic, paleoenvironmental, and paleobiogeographic synthesis, equatorial Atlantic

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    Cretaceous sediments from Ocean Drilling Program Leg 159 on the Cîte d’Ivoire-Ghana Marginal Ridge (CIGMR), eastern equatorial Atlantic, are characterized by distinct stratigraphic changes in sedimentary facies associated with changes in the composition of the clayey and organic fractions, as well as of the calcareous nannofossil, radiolarian, foraminiferal, and palynomorph assemblages. In the absence of reliable magnetostratigraphic information, an integrated biostratigraphy provides the only means used to calibrate the geologic history of the Leg 159 area. The existence of marine depositional environments as early as the late Aptian to early Albian close to the Leg 159 drill sites puts constraints on the timing of the opening of the equatorial Atlantic gateway. Marine sedimentation on the ridge suggests that the West African and South American cratons were largely detached at this segment of the margin by the middle to late Albian. During the Cenomanian to Coniacian the ridge appears to have remained in an elevated position with concurrent low deposition or condensation (Site 959), high carbonate debris accumulation (Site 960), and even erosion (Site 962). Total organic Carbon measurements and microfaunal data lead us to suggest that, following the early opening of the seaway during the Albian, circulation remained restricted in the fragmented sub-basins of the CIGMR. It probably was not until the Santonian that a deep-water connection and circulation system became established between the Central and the South Atlantic. The sedimentary and faunal record at Site 959 show that a rapid subsidence occurred during the Santonian, with sub-calcite compensation depth conditions maintained until and beyond the Cretaceous/Tertiary boundary
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