717 research outputs found

    Quantitative imaging of the Dorsal nuclear gradient reveals limitations to threshold-dependent patterning in Drosophila

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    The NF-κB-related transcription factor, Dorsal, forms a nuclear concentration gradient in the early Drosophila embryo, patterning the dorsal-ventral (DV) axis to specify mesoderm, neurogenic ectoderm, and dorsal ectoderm cell fates. The concentration of nuclear Dorsal is thought to determine these patterning events; however, the levels of nuclear Dorsal have not been quantified previously. Furthermore, existing models of Dorsal-dependent germ layer specification and patterning consider steady-state levels of Dorsal relative to target gene expression patterns, yet both Dorsal gradient formation and gene expression are dynamic. We devised a quantitative imaging method to measure the Dorsal nuclear gradient while simultaneously examining Dorsal target gene expression along the DV axis. Unlike observations from other insects such as Tribolium, we find the Dorsal gradient maintains a constant bell-shaped distribution during embryogenesis. We also find that some classical Dorsal target genes are located outside the region of graded Dorsal nuclear localization, raising the question of whether these genes are direct Dorsal targets. Additionally, we show that Dorsal levels change in time during embryogenesis such that a steady state is not reached. These results suggest that the multiple gene expression outputs observed along the DV axis do not simply reflect a steady-state Dorsal nuclear gradient. Instead, we propose that the Dorsal gradient supplies positional information throughout nuclear cycles 10-14, providing additional evidence for the idea that compensatory combinatorial interactions between Dorsal and other factors effect differential gene expression along the DV axis

    Report of IRPA task group on the impact of the eye lens dose limits

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    In 2012 IRPA established a task group (TG) to identify key issues in the implementation of the revised eye lens dose limit. The TG reported its conclusions in 2013. In January 2015, IRPA asked the TG to review progress with the implementation of the recommendations from the early report and to collate current practitioner experience. This report presents the results of a survey on the view of the IRPA professionals on the new limit to the lens of the eye and on the wider issue of tissue reactions. Recommendations derived from the survey are presented. This report was approved by IRPA Executive Council on 31 January 2017

    Protein interacting with C kinase 1 suppresses invasion and anchorage independent growth of astrocytic tumour cells

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    Astrocytic tumors are the most common form of primary brain tumor. Astrocytic tumor cells infiltrate the surrounding CNS tissue, allowing them to evade removal upon surgical resection of the primary tumor. Dynamic changes to the actin cytoskeleton are crucial to cancer cell invasion, but the specific mechanisms that underlie the particularly invasive phenotype of astrocytic tumor cells are unclear. Protein interacting with C kinase 1 (PICK1) is a PDZ and BAR domain–containing protein that inhibits actin-related protein 2/3 (Arp2/3)-dependent actin polymerization and is involved in regulating the trafficking of a number of cell-surface receptors. Here we report that, in contrast to other cancers, PICK1 expression is down-regulated in grade IV astrocytic tumor cell lines and also in clinical cases of the disease in which grade IV tumors have progressed from lower-grade tumors. Exogenous expression of PICK1 in the grade IV astrocytic cell line U251 reduces their capacity for anchorage-independent growth, two-dimensional migration, and invasion through a three-dimensional matrix, strongly suggesting that low PICK1 expression plays an important role in astrocytic tumorigenesis. We propose that PICK1 negatively regulates neoplastic infiltration of astrocytic tumors and that manipulation of PICK1 is an attractive possibility for therapeutic intervention

    Comparison of Dermatophytes and Other Agents of Human Dermatitis between Males and Females in Jos, Plateau State, Nigeria

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    Dermatophytes are a group of three genera of fungi namely Microsporum spp, Trichophyton spp and Epidermophyton spp that commonly cause infections of the skin, hair and nails due to their ability to utilize keratin in both man and animals. Dermatophytes and other agents of human dermatitis are believed to have gender predisposition because of the anatomical and physiological nature of these genders. A study was undertaken to compare the distribution of dermatophytes and other agents of human dermatitis in patients who visited the Dermatophilosis Research Laboratory, National Veterinary Research Institute, Vom, Plateau State of Nigeria. A total of 1551 patients were involved in this study from 2003 to 2007; 823 of whom were males and 728 females. Samples collected were skin scrapping, nails, hair and pus exudates. They were processed according to standard procedures. Nine hundred and thirty two (60%) were positive for dermatophytes and other agents. Sporothrix schenckii (138 (12.4%)), Aspergillus flavus (128 (11.5%)), and Trichophyton mentagrophytes (112 (10.1%)), Mucor sp (105 (9.5%)) were the most commonly isolated fungi. Aspergillus flavus occurred more in males (74 (6.7%)) while Sporothrix schenckii was more in females (71 (6.4%)). More isolation was made from the head in males (185 (19.8%)) while in females more isolation was made from their limbs (150 (16.1%)). Males generally were more affected with skin infections than females

    The theme of protest and its expression in S. F. Motlhake's poetry

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    In the Apartheid South Africa, repression and the heightening of the Blacks' struggle for political emancipation, prompted artists to challenge the system through their music, oral poetry and writing. Most produced works of protest in English to reach a wider audience. This led to the general misconception that literatures in the indigenous languages of South Africa were insensitive to the issues of those times. This study seeks firstly to put to rest such misconception by proving that there is Commitment in these literatures as exemplified in the poetry of S.F. Motlhake. Motlhake not only expresses protest against the political system of the time, but also questions some religious and socio-cultural practices and institutions among his people. The study also examines his selected works as genuine poetry, which does not sacrifice art on the altar of propaganda.African LanguagesM.A. (African Languages

    Measurements of the vertical profile, diurnal variation, and secular change of ClO in the stratosphere over Thule, Greenland, February-March, 1992

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    We report observations of stratospheric chlorine monoxide over the altitude range approx. 16 to 50 km at Thule, Greenland from Feb. 8 to Mar. 24, 1992. A new, more sensitive ground-based mm-wave spectrometer was employed for these measurements, similar in principle to that used earlier for the discovery of low altitude ClO in the Antarctic springtime. In this report, we discuss different aspects of vertical distribution, secular trends, and diurnal variation of ClO in the Arctic stratosphere, based on a preliminary analysis of our Thule data. We see no evidence for large (approx. 1.2-1.5 ppb) amounts of ClO in the lower stratosphere at any time during February or March, in agreement with UARS-MLS findings for this period, and in marked contrast to findings reported for the Arctic in January. We have some evidence for small enhancements (approx. 0.2-0.5 ppb) in the 18-30 km range in late February-early March, which might be associated with volcanic aerosol, rather than PSC, processing

    Observed changes in the vertical profile of stratopheric nitrous oxide at Thule, Greenland, February - March 1992

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    Using a ground-based mm-wave spectrometer, we have observed stratospheric N2O over Thule, Greenland (76.3 N, 68.4 W) during late February and March, 1992. Vertical profiles of mixing ratio ranging from 16 to 50 km were recovered from molecular emission spectra. The profiles of early March show an abrupt increase in the lower-stratosphere N2O mixing ratio similar to the spring-to-summer change associated with the break up of the Antarctic polar vortex. This increase is correlated with changes in potential vorticity, air temperature, and ozone mixing ratio

    Palliative care initiation in pediatric oncology patients: A systematic review

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    Palliative care (PC) aims to improve quality of life for patients and their families. The World Health Organization and American Academy of Pediatrics recommend that PC starts at diagnosis for children with cancer. This systematic review describes studies that reported PC timing in the pediatric oncology population. The following databases were searched: PubMed, Web of Science, CINAHL, and PsycInfo databases. Studies that reported time of PC initiation were independently screened and reviewed by 2 researchers. Studies describing pilot initiatives, published prior to 1998, not written in English, or providing no empirical time information on PC were excluded. Extracted data included sample characteristics and timing of PC discussion and initiation. Of 1120 identified citations, 16 articles met the inclusion criteria and comprised the study cohort. Overall, 54.5% of pediatric oncology patients received any palliative service prior to death. Data revealed PC discussion does not occur until late in the illness trajectory, and PC does not begin until close to time of death. Despite efforts to spur earlier initiation, many pediatric oncology patients do not receive any palliative care service, and those who do, predominantly receive it near the time of death. Delays occur both at first PC discussion and at PC initiation. Efforts for early PC integration must recognize the complex determinants of PC utilization across the illness timeline

    A 15 year slow-slip event on the Sunda megathrust offshore Sumatra

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    In the Banyak Islands of Sumatra, coral microatoll records reveal a 15 year-long reversal of interseismic vertical displacement from subsidence to uplift between 1966 and 1981. To explain these coral observations, we test four hypotheses, including regional sea level changes and various tectonic mechanisms. Our results show that the coral observations likely reflect a 15 year-long slow-slip event (SSE) on the Sunda megathrust. This long-duration SSE exceeds the duration of previously reported SSEs and demonstrates the importance of multidecade geodetic records in illuminating the full spectrum of megathrust slip behavior at subduction zones
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