312 research outputs found

    Earliest Triassic microbialites in the South China Block and other areas; controls on their growth and distribution

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    Earliest Triassic microbialites (ETMs) and inorganic carbonate crystal fans formed after the end-Permian mass extinction (ca. 251.4 Ma) within the basal Triassic Hindeodus parvus conodont zone. ETMs are distinguished from rarer, and more regional, subsequent Triassic microbialites. Large differences in ETMs between northern and southern areas of the South China block suggest geographic provinces, and ETMs are most abundant throughout the equatorial Tethys Ocean with further geographic variation. ETMs occur in shallow-marine shelves in a superanoxic stratified ocean and form the only widespread Phanerozoic microbialites with structures similar to those of the Cambro-Ordovician, and briefly after the latest Ordovician, Late Silurian and Late Devonian extinctions. ETMs disappeared long before the mid-Triassic biotic recovery, but it is not clear why, if they are interpreted as disaster taxa. In general, ETM occurrence suggests that microbially mediated calcification occurred where upwelled carbonate-rich anoxic waters mixed with warm aerated surface waters, forming regional dysoxia, so that extreme carbonate supersaturation and dysoxic conditions were both required for their growth. Long-term oceanic and atmospheric changes may have contributed to a trigger for ETM formation. In equatorial western Pangea, the earliest microbialites are late Early Triassic, but it is possible that ETMs could exist in western Pangea, if well-preserved earliest Triassic facies are discovered in future work

    Phase i trial of axitinib combined with platinum doublets in patients with advanced non-small cell lung cancer and other solid tumours

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    BACKGROUND: This phase I dose-finding trial evaluated safety, efficacy and pharmacokinetics of axitinib, a potent and selective secondgeneration inhibitor of vascular endothelial growth factor receptors, combined with platinum doublets in patients with advanced non-small cell lung cancer (NSCLC) and other solid tumours. METHODS: In all, 49 patients received axitinib 5mg twice daily (b.i.d.) with paclitaxel/carboplatin or gemcitabine/cisplatin in 3-week cycles. Following determination of the maximum tolerated dose, a squamous cell NSCLC expansion cohort was enroled and received axitinib 5mg b.i.d. with paclitaxel/carboplatin. RESULTS: Two patients experienced dose-limiting toxicities: febrile neutropenia (n¼1) in the paclitaxel/carboplatin cohort and fatigue (n¼1) in the gemcitabine/cisplatin cohort. Common nonhaematologic treatment-related adverse events were hypertension (36.7%), diarrhoea (34.7%) and fatigue (28.6%). No gradeX3 haemoptysis occurred among 12 patients with squamous cell NSCLC. The objective response rate was 37.0% for patients receiving axitinib/paclitaxel/carboplatin (n¼27) and 23.8% for patients receiving axitinib/gemcitabine/cisplatin (n¼21). Pharmacokinetics of axitinib and chemotherapeutic agents were similar when administered alone or in combination. CONCLUSION: Axitinib 5mg b.i.d. may be combined with standard paclitaxel/carboplatin or gemcitabine/cisplatin regimens without evidence of overt drug–drug interactions. Both combinations demonstrated clinical efficacy and were well tolerated.This study was sponsored by Pfizer Inc. Support was provided in part by National Institutes of Health grant P30 CA006927 to the Fox Chase Cancer Center. We thank the patients who participated in this study and the physicians who referred them, as well as the study coordinators and data managers, Shelley Mayfield and Carol Martins at Pfizer Inc. for support of the study conduct, and Gamal ElSawah, Pfizer Medical Affairs, for his review of the manuscript. Medical writing support was provided by Joanna Bloom, of UBC Scientific Solutions (Southport, CT, USA) and Christine Arris at ACUMED (Tytherington, UK) and was funded by Pfizer In

    The regulation of IL-10 expression

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    Interleukin (IL)-10 is an important immunoregulatory cytokine and an understanding of how IL-10 expression is controlled is critical in the design of immune intervention strategies. IL-10 is produced by almost all cell types within the innate (including macrophages, monocytes, dendritic cells (DCs), mast cells, neutrophils, eosinophils and natural killer cells) and adaptive (including CD4(+) T cells, CD8(+) T cells and B cells) immune systems. The mechanisms of IL-10 regulation operate at several stages including chromatin remodelling at the Il10 locus, transcriptional regulation of Il10 expression and post-transcriptional regulation of Il10 mRNA. In addition, whereas some aspects of Il10 gene regulation are conserved between different immune cell types, several are cell type- or stimulus-specific. Here, we outline the complexity of IL-10 production by discussing what is known about its regulation in macrophages, monocytes, DCs and CD4(+) T helper cells

    Anti-angiogenic therapy for cancer: Current progress, unresolved questions and future directions

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    Tumours require a vascular supply to grow and can achieve this via the expression of pro-angiogenic growth factors, including members of the vascular endothelial growth factor (VEGF) family of ligands. Since one or more of the VEGF ligand family is overexpressed in most solid cancers, there was great optimism that inhibition of the VEGF pathway would represent an effective anti-angiogenic therapy for most tumour types. Encouragingly, VEGF pathway targeted drugs such as bevacizumab, sunitinib and aflibercept have shown activity in certain settings. However, inhibition of VEGF signalling is not effective in all cancers, prompting the need to further understand how the vasculature can be effectively targeted in tumours. Here we present a succinct review of the progress with VEGF-targeted therapy and the unresolved questions that exist in the field: including its use in different disease stages (metastatic, adjuvant, neoadjuvant), interactions with chemotherapy, duration and scheduling of therapy, potential predictive biomarkers and proposed mechanisms of resistance, including paradoxical effects such as enhanced tumour aggressiveness. In terms of future directions, we discuss the need to delineate further the complexities of tumour vascularisation if we are to develop more effective and personalised anti-angiogenic therapies. © 2014 The Author(s)

    Randomised, non-comparative phase II study of weekly docetaxel with cisplatin and 5-fluorouracil or with capecitabine in oesophagogastric cancer: the AGITG ATTAX trial

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    BACKGROUND: Docetaxel administered 3-weekly with cisplatin and 5-fluorouracil leads to better survival than does standard therapy in patients with oesophagogastric cancer, but leads to high rates of haematological toxicity. Weekly docetaxel is associated with less haematological toxicity. This randomised phase II study tested weekly docetaxel-based combination chemotherapy regimens, with the aim of maintaining their activity while reducing toxicity. METHODS: Patients with histologically confirmed metastatic oesophageal or gastric carcinoma were randomised to receive weekly docetaxel (30 mg m(-2)) on days 1 and 8, cisplatin (60 mg m(-2)) on day 1, and 5-fluorouracil (200 mg m(-2) per day) continuously, every 3 weeks (weekly TCF, wTCF); or docetaxel (30 mg m(-2)) on days 1 and 8 and capecitabine (1600 mg m(-2) per day) on days 1-14, every 3 weeks (weekly TX, wTX). RESULTS: A total of 106 patients were enrolled (wTCF, n=50; wTX, n=56). Response rates, the primary end point, were 47% with wTCF and 26% with wTX. Rates of febrile neutropenia were low in each arm. Median progression-free and overall survival times were 5.9 and 11.2 months for wTCF and 4.6 and 10.1 months for wTX, respectively. CONCLUSION: Weekly TCF and TX have encouraging activity and less haematological toxicity than TCF administered 3-weekly. Weekly docetaxel-based combination regimens warrant further evaluation in this disease

    Analysis for genotyping Duffy blood group in inhabitants of Sudan, the Fourth Cataract of the Nile

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    <p>Abstract</p> <p>Background</p> <p>Genetic polymophisms of the Duffy antigen receptor for the chemokines (DARC) gene successfully protected against blood stage infection by <it>Plasmodium vivax </it>infection. The Fy (a-, b-) phenotype is predominant among African populations, particularly those originating from West Africa, and it is rare among non-African populations. The aim of this study was to analyse the frequency of four Duffy blood groups based on SNPs (T-33C, G125A, G298A and C5411T) in two local tribes of Sudanese Arabs, the <it>Shagia </it>and <it>Manasir</it>, which are both from the region of the Fourth Nile cataract in Sudan.</p> <p>Methods</p> <p>An analysis of polymorphisms was performed on 217 individuals (126 representatives of the <it>Shagia </it>tribe and 91 of the <it>Manasir)</it>. Real-time PCR and TaqMan Genotyping Assays were used to study the prevalence of alleles and genotypes.</p> <p>Results</p> <p>The analysis of allelic and genotype frequency in the T-33C polymorphisms demonstrated a significant dominance of the <it>C </it>allele and <it>CC </it>genotype (OR = 0.53 [0.32-0.88]; p = 0.02) in both tribes. The G125A polymorphism is associated with phenotype Fy(a-, b-) and was identified in 83% of <it>Shagia </it>and 77% of <it>Manasir</it>. With regard to G298A polymorphisms, the genotype frequencies were different between the tribes (p = 0,002) and no single <it>AA </it>homozygote was found. Based on four SNPs examined, 20 combinations of genotypes for the <it>Shagia </it>and <it>Manasir </it>tribes were determined. The genotype <it>CC/AA/GG/CT </it>occurred most often in <it>Shagia </it>tribe (45.9%) but was rare in the <it>Manasir </it>tribe (6.6%) (p < 0.001 <it>Shagia </it>versus <it>Manasir</it>). The <it>FY*A<sup>ES </sup></it>allele was identified in both analysed tribes. The presence of individuals with the <it>FY*A/FY*A </it>genotype was demonstrated only in the <it>Shagia </it>tribe.</p> <p>Conclusion</p> <p>This is probably the first report showing genotypically Duffy-negative people who carry both <it>FY*B<sup>ES </sup></it>and <it>FY*A<sup>ES</sup></it>. The identification of the <it>FY*A<sup>ES </sup></it>allele in both tribes may be due to admixture of the non-African genetic background. Taken as a whole, allele and genotype frequencies between the <it>Shagia </it>and the <it>Manasir </it>were statistically different. However, the presence of individuals with the <it>FY*A/FY*A </it>genotype was demonstrated only in the <it>Shagia </it>tribe.</p

    ADHD and EEG-neurofeedback: a double-blind randomized placebo-controlled feasibility study

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    Electroencephalography (EEG)-neurofeedback has been shown to offer therapeutic benefits to patients with attention-deficit/hyperactivity disorder (ADHD) in several, mostly uncontrolled studies. This pilot study is designed to test the feasibility and safety of using a double-blind placebo feedback-controlled design and to explore the initial efficacy of individualized EEG-neurofeedback training in children with ADHD. Fourteen children (8–15 years) with ADHD defined according to the DSM-IV-TR criteria were randomly allocated to 30 sessions of EEG-neurofeedback (n = 8) or placebo feedback (n = 6). Safety measures (adverse events and sleep problems), ADHD symptoms and global improvement were monitored. With respect to feasibility, all children completed the study and attended all study visits and training sessions. No significant adverse effects or sleep problems were reported. Regarding the expectancy, 75% of children and their parent(s) in the active neurofeedback group and 50% of children and their parent(s) in the placebo feedback group thought they received placebo feedback training. Analyses revealed significant improvements of ADHD symptoms over time, but changes were similar for both groups. This pilot study shows that it is feasible to conduct a rigorous placebo-controlled trial to investigate the efficacy of neurofeedback training in children with ADHD. However, a double-blind design may not be feasible since using automatic adjusted reward thresholds may not work as effective as manually adjusted reward thresholds. Additionally, implementation of active learning strategies may be an important factor for the efficacy of EEG-neurofeedback training. Based on the results of this pilot study, changes are made in the design of the ongoing study

    Vascular disrupting agents in clinical development

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    Growth of human tumours depends on the supply of oxygen and nutrients via the surrounding vasculature. Therefore tumour vasculature is an attractive target for anticancer therapy. Apart from angiogenesis inhibitors that compromise the formation of new blood vessels, a second class of specific anticancer drugs has been developed. These so-called vascular disrupting agents (VDAs) target the established tumour vasculature and cause an acute and pronounced shutdown of blood vessels resulting in an almost complete stop of blood flow, ultimately leading to selective tumour necrosis. As a number of VDAs are now being tested in clinical studies, we will discuss their mechanism of action and the results obtained in preclinical studies. Also data from clinical studies will be reviewed and some considerations with regard to the future development are given

    Fluorescent Labeling of Newborn Dentate Granule Cells in GAD67-GFP Transgenic Mice: A Genetic Tool for the Study of Adult Neurogenesis

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    Neurogenesis in the adult hippocampus is an important form of structural plasticity in the brain. Here we report a line of BAC transgenic mice (GAD67-GFP mice) that selectively and transitorily express GFP in newborn dentate granule cells of the adult hippocampus. These GFP+ cells show a high degree of colocalization with BrdU-labeled nuclei one week after BrdU injection and express the newborn neuron marker doublecortin and PSA-NCAM. Compared to mature dentate granule cells, these newborn neurons show immature morphological features: dendritic beading, fewer dendritic branches and spines. These GFP+ newborn neurons also show immature electrophysiological properties: higher input resistance, more depolarized resting membrane potentials, small and non-typical action potentials. The bright labeling of newborn neurons with GFP makes it possible to visualize the details of dendrites, which reach the outer edge of the molecular layer, and their axon (mossy fiber) terminals, which project to the CA3 region where they form synaptic boutons. GFP expression covers the whole developmental stage of newborn neurons, beginning within the first week of cell division and disappearing as newborn neurons mature, about 4 weeks postmitotic. Thus, the GAD67-GFP transgenic mice provide a useful genetic tool for studying the development and regulation of newborn dentate granule cells
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