112 research outputs found

    Mastermind Acts Downstream of Notch to Specify Neuronal Cell Fates in theDrosophilaCentral Nervous System

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    AbstractIn theDrosophilacentral nervous system, cellular diversity is generated through the asymmetric partitioning of cell fate determinants at cell division. Neural precursors (or neuroblasts) divide in a stem cell lineage to generate a series of ganglion mother cells, each of which divides once to produce a pair of postmitotic neurons or glial cells. An exception to this rule is the MP2 neuroblast, which divides only once to generate two neurons. We screened for genes expressed in the MP2 neuroblast and its progeny as a means of identifying the factors that specify cell fate in the MP2 lineage. We identified a P-element insertion line that expresses the reporter gene, tau-β-galactosidase, in the MP2 precursor and its progeny, the vMP2 and dMP2 neurons. The transposon disrupts the neurogenic gene,mastermind,but does not lead to neural hyperplasia. However, the vMP2 neuron is transformed into its sibling cell, dMP2. By contrast, expression of a dominant activated form of the Notch receptor in the MP2 lineage transforms dMP2 to vMP2. Notch signalling requires Mastermind, suggesting that Mastermind acts downstream of Notch to determine the vMP2 cell fate. We show that Mastermind plays a similar role in the neurons derived from ganglion mother cells 1-1a and 4-2a, where it specifies the pCC and RP2sib fates, respectively. This suggests that Notch signalling through Mastermind plays a wider role in specifying neuronal identity in theDrosophilacentral nervous system

    Estimates of Alpha/Beta (alpha/beta) Ratios for Individual Late Rectal Toxicity Endpoints: An Analysis of the CHHiP Trial

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    Purpose: Changes in fraction size of external beam radiation therapy exert nonlinear effects on subsequent toxicity. Commonly described by the linear-quadratic model, fraction size sensitivity of normal tissues is expressed by the α/β ratio. We sought to study individual α/β ratios for different late rectal effects after prostate external beam radiation therapy. Methods and Materials: The CHHiP trial (ISRCTN97182923) randomized men with nonmetastatic prostate cancer 1:1:1 to 74 Gy/37 fractions (Fr), 60 Gy/20 Fr, or 57 Gy/19 Fr. Patients in the study had full dosimetric data and zero baseline toxicity. Toxicity scales were amalgamated to 6 bowel endpoints: bleeding, diarrhea, pain, proctitis, sphincter control, and stricture. Lyman-Kutcher-Burman models with or without equivalent dose in 2 Gy/Fr correction were log-likelihood fitted by endpoint, estimating α/β ratios. The α/β ratio estimate sensitivity was assessed using sequential inclusion of dose modifying factors (DMFs): age, diabetes, hypertension, inflammatory bowel or diverticular disease (IBD/diverticular), and hemorrhoids. 95% confidence intervals (CIs) were bootstrapped. Likelihood ratio testing of 632 estimator log-likelihoods compared the models. Results: Late rectal α/β ratio estimates (without DMF) ranged from bleeding (G1 + α/β = 1.6 Gy; 95% CI, 0.9-2.5 Gy) to sphincter control (G1 + α/β = 3.1 Gy; 95% CI, 1.4-9.1 Gy). Bowel pain modelled poorly (α/β, 3.6 Gy; 95% CI, 0.0-840 Gy). Inclusion of IBD/diverticular disease as a DMF significantly improved fits for stool frequency G2+ (P = .00041) and proctitis G1+ (P = .00046). However, the α/β ratios were similar in these no-DMF versus DMF models for both stool frequency G2+ (α/β 2.7 Gy vs 2.5 Gy) and proctitis G1+ (α/β 2.7 Gy vs 2.6 Gy). Frequency-weighted averaging of endpoint α/β ratios produced: G1 + α/β ratio = 2.4 Gy; G2 + α/β ratio = 2.3 Gy. Conclusions: We estimated α/β ratios for several common late adverse effects of rectal radiation therapy. When comparing dose-fractionation schedules, we suggest using late a rectal α/β ratio ≤ 3 Gy

    Genitourinary α/β Ratios in the CHHiP Trial the Fraction Size Sensitivity of Late Genitourinary Toxicity: Analysis of Alpha/Beta (α/β) Ratios in the CHHiP Trial

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    PURPOSE: Moderately hypofractionated external beam intensity-modulated radiotherapy (IMRT) for prostate cancer is now standard-of-care. Normal tissue toxicity responses to fraction size alteration are non-linear: the linear-quadratic model is a widely-used framework accounting for this, through the α/β ratio. Few α/β ratio estimates exist for human late genitourinary endpoints; here we provide estimates derived from a hypofractionation trial. METHODS AND MATERIALS: The XXXXXX trial randomised 3216 men with localised prostate cancer 1:1:1 between conventionally fractionated IMRT (74Gy/37 fractions (Fr)) and two moderately hypofractionated regimens (60Gy/20Fr & 57Gy/19Fr). Radiotherapy plan and suitable follow-up assessment was available for 2206 men. Three prospectively assessed clinician-reported toxicity scales were amalgamated for common genitourinary endpoints: Dysuria, Haematuria, Incontinence, Reduced flow/Stricture, Urine Frequency. Per endpoint, only patients with baseline zero toxicity were included. Three models for endpoint grade ≥1 (G1+) and G2+ toxicity were fitted: Lyman Kutcher-Burman (LKB) without equivalent dose in 2Gy/Fr (EQD2) correction [LKB-NoEQD2]; LKB with EQD2-correction [LKB-EQD2]; LKB-EQD2 with dose-modifying-factor (DMF) inclusion [LKB-EQD2-DMF]. DMFs were: age, diabetes, hypertension, pelvic surgery, prior transurethral resection of prostate (TURP), overall treatment time and acute genitourinary toxicity (G2+). Bootstrapping generated 95% confidence intervals and unbiased performance estimates. Models were compared by likelihood ratio test. RESULTS: The LKB-EQD2 model significantly improved performance over LKB-NoEQD2 for just three endpoints: Dysuria G1+ (α/β=2.0 Gy, 95%CI 1.2-3.2Gy), Haematuria G1+ (α/β=0.9 Gy, 95%CI 0.1-2.2Gy) and Haematuria G2+ (α/β=0.6Gy, 95%CI 0.1-1.7Gy). For these three endpoints, further incorporation of two DMFs improved on LKB-EQD2: acute genitourinary toxicity and Prior TURP (Haematuria G1+ only), but α/β ratio estimates remained stable. CONCLUSIONS: Inclusion of EQD2-correction significantly improved model fitting for Dysuria and Haematuria endpoints, where fitted α/β ratio estimates were low: 0.6-2 Gy. This suggests therapeutic gain for clinician-reported GU toxicity, through hypofractionation, might be lower than expected by typical late α/β ratio assumptions of 3-5 Gy

    Exercise during chemotherapy for ovarian cancer (ECHO) trial : design and implementation of a randomised controlled trial

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    Introduction Epidemiological evidence supports an association between higher levels of physical activity and improved cancer survival. Trial evidence is now needed to demonstrate the effect of exercise in a clinical setting. The Exercise during CHemotherapy for Ovarian cancer (ECHO) trial is a phase III, randomised controlled trial, designed to determine the effect of exercise on progression-free survival and physical well-being for patients receiving first-line chemotherapy for ovarian cancer. Methods and analysis Participants (target sample size n=500) include women with newly diagnosed primary ovarian cancer, scheduled to receive first-line chemotherapy. Consenting participants are randomly allocated (1:1) to either the exercise intervention (plus usual care) or usual care alone, with stratification for recruitment site, age, stage of disease and chemotherapy delivery (neoadjuvant vs adjuvant). The exercise intervention involves individualised exercise prescription with a weekly target of 150 minutes of moderate-intensity, mixed-mode exercise (equivalent to 450 metabolic equivalent minutes per week), delivered for the duration of first-line chemotherapy through weekly telephone sessions with a trial-trained exercise professional. The primary outcomes are progression-free survival and physical well-being. Secondary outcomes include overall survival, physical function, body composition, quality of life, fatigue, sleep, lymphoedema, anxiety, depression, chemotherapy completion rate, chemotherapy-related adverse events, physical activity levels and healthcare usage. Ethics and dissemination Ethics approval for the ECHO trial (2019/ETH08923) was granted by the Sydney Local Health District Ethics Review Committee (Royal Prince Alfred Zone) on 21 November 2014. Subsequent approvals were granted for an additional 11 sites across Queensland, New South Wales, Victoria and the Australian Capital Territory. Findings from the ECHO trial are planned to be disseminated via peer-reviewed publications and international exercise and oncology conferences

    DNA Methylation Profiles of Ovarian Clear Cell Carcinoma

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    BACKGROUND: Ovarian clear cell carcinoma (OCCC) is a rare ovarian cancer histotype that tends to be resistant to standard platinum-based chemotherapeutics. We sought to better understand the role of DNA methylation in clinical and biological subclassification of OCCC. METHODS: We interrogated genome-wide methylation using DNA from fresh frozen tumors from 271 cases, applied non-smooth non-negative matrix factorization (nsNMF) clustering, and evaluated clinical associations and biological pathways. RESULTS: Two approximately equally sized clusters that associated with several clinical features were identified. Compared to Cluster 2 (N=137), Cluster 1 cases (N=134) presented at a more advanced stage, were less likely to be of Asian ancestry, and tended to have poorer outcomes including macroscopic residual disease following primary debulking surgery (p-values <0.10). Subset analyses of targeted tumor sequencing and immunohistochemical data revealed that Cluster 1 tumors showed TP53 mutation and abnormal p53 expression, and Cluster 2 tumors showed aneuploidy and ARID1A/PIK3CA mutation (p-values <0.05). Cluster-defining CpGs included 1,388 CpGs residing within 200 bp of the transcription start sites of 977 genes; 38% of these genes (N=369 genes) were differentially expressed across cluster in transcriptomic subset analysis (p-values <10(−4)). Differentially expressed genes were enriched for six immune-related pathways, including interferon alpha and gamma responses (p-values < 10(−6)). CONCLUSIONS: DNA methylation clusters in OCCC correlate with disease features and gene expression patterns among immune pathways. IMPACT: This work serves as a foundation for integrative analyses that better understand the complex biology of OCCC in an effort to improve potential for development of targeted therapeutics

    Disability, fatigue, pain and their associates in early diffuse cutaneous systemic sclerosis: the European Scleroderma Observational Study

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    Objectives; Our aim was to describe the burden of early dcSSc in terms of disability, fatigue and pain in the European Scleroderma Observational Study cohort, and to explore associated clinical features. Methods; Patients completed questionnaires at study entry, 12 and 24 months, including the HAQ disability index (HAQ-DI), the Cochin Hand Function Scale (CHFS), the Functional Assessment of Chronic Illness Therapy-fatigue and the Short Form 36 (SF36). Associates examined included the modified Rodnan skin score (mRSS), current digital ulcers and internal organ involvement. Correlations between 12-month changes were also examined. Results; The 326 patients recruited (median disease duration 11.9 months) displayed high levels of disability [mean (S.D.) HAQ-DI 1.1 (0.83)], with ‘grip’ and ‘activity’ being most affected. Of the 18 activities assessed in the CHFS, those involving fine finger movements were most affected. High HAQ-DI and CHFS scores were both associated with high mRSS (ρ = 0.34, P < 0.0001 and ρ = 0.35, P < 0.0001, respectively). HAQ-DI was higher in patients with digital ulcers (P = 0.004), pulmonary fibrosis (P = 0.005), cardiac (P = 0.005) and muscle involvement (P = 0.002). As anticipated, HAQ-DI, CHFS, the Functional Assessment of Chronic Illness Therapy and SF36 scores were all highly correlated, in particular the HAQ-DI with the CHFS (ρ = 0.84, P < 0.0001). Worsening HAQ-DI over 12 months was strongly associated with increasing mRSS (ρ = 0.40, P < 0.0001), decreasing hand function (ρ = 0.57, P < 0.0001) and increasing fatigue (ρ = −0.53, P < 0.0001). Conclusion; The European Scleroderma Observational Study highlights the burden of disability in early dcSSc, with high levels of disability and fatigue, associating with the degree of skin thickening (mRSS). Impaired hand function is a major contributor to overall disability

    Subaqueous basaltic magmatic explosions trigger phreatomagmatism: a case study from Askja, Iceland

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    Sequences of basaltic pillow lavas that transition upwards with systematic gradation from pillow fragment breccias to fluidal bomb-bearing breccia to bomb-bearing lapilli tuffs are common at Askja volcano, Iceland. Based on the detailed textural investigation of three of these sequences, we argue that they record temporally continuous transition from effusive to explosive products that were erupted from and deposited at or near a single subaqueous vent. The recognition of such sequences is important as they provide evidence for controls on the onset of explosive activity in subaqueous environments. Such investigations are complicated by the interplay of magmatic gas expansion, phreatomagmatic and mechanical granulation fragmentation mechanisms in the subaqueous eruptive environment. All of the sequences studied at Askja have textural, componentry and sedimentological characteristics suggestive of a close genetic and spatial relationship between the pillow lavas and all of the overlying glassy clastic deposits. The identification of magma fragmentation signatures in pyroclasts was accomplished through detailed textural studies of pyroclasts within the full range of grain sizes of a given deposit i.e. bomb/blocks, lapilli and fine ash. These textural characteristics were compared and evaluated as discriminators of fragmentation in pyroclastic deposits. The presence of angular vitric clasts within the breccia and lapilli tuff displaying fragile glassy projections indicates little or no postdepositional textural modification. A shift in vesicle and clast textures between the pillow lavas and the large concentration of fluidal bombs in the breccia indicate that the phreatomagmatic explosions were initially triggered by magmatic vesiculation. The initial magmatic gas expansion may have been triggered by depressurization caused by the drainage of the ice-confined lake surrounding Askja. The Fuel Coolant Interactions (FCI) of the more efficient phreatomagmatic explosion was enabled by the increase in the surface area to volume ratio of the fluidal bombs in the water, producing a premix of magma and water. The onset and increasing influence of phreatomagmatic fragmentation is preserved in the presence of very fine blocky ash particles and diminished presence of larger particles such as fluidal bombs. The textural, sedimentological and environmental characteristics of these deposits suggest that phreatomagmatic explosions can be triggered by initial magmatic gas expansion, but that it is likely one of many mechanisms for triggering such explosions

    Comparison of Expression Profiles in Ovarian Epithelium In Vivo and Ovarian Cancer Identifies Novel Candidate Genes Involved in Disease Pathogenesis

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    Molecular events leading to epithelial ovarian cancer are poorly understood but ovulatory hormones and a high number of life-time ovulations with concomitant proliferation, apoptosis, and inflammation, increases risk. We identified genes that are regulated during the estrous cycle in murine ovarian surface epithelium and analysed these profiles to identify genes dysregulated in human ovarian cancer, using publically available datasets. We identified 338 genes that are regulated in murine ovarian surface epithelium during the estrous cycle and dysregulated in ovarian cancer. Six of seven candidates selected for immunohistochemical validation were expressed in serous ovarian cancer, inclusion cysts, ovarian surface epithelium and in fallopian tube epithelium. Most were overexpressed in ovarian cancer compared with ovarian surface epithelium and/or inclusion cysts (EpCAM, EZH2, BIRC5) although BIRC5 and EZH2 were expressed as highly in fallopian tube epithelium as in ovarian cancer. We prioritised the 338 genes for those likely to be important for ovarian cancer development by in silico analyses of copy number aberration and mutation using publically available datasets and identified genes with established roles in ovarian cancer as well as novel genes for which we have evidence for involvement in ovarian cancer. Chromosome segregation emerged as an important process in which genes from our list of 338 were over-represented including two (BUB1, NCAPD2) for which there is evidence of amplification and mutation. NUAK2, upregulated in ovarian surface epithelium in proestrus and predicted to have a driver mutation in ovarian cancer, was examined in a larger cohort of serous ovarian cancer where patients with lower NUAK2 expression had shorter overall survival. In conclusion, defining genes that are activated in normal epithelium in the course of ovulation that are also dysregulated in cancer has identified a number of pathways and novel candidate genes that may contribute to the development of ovarian cancer

    Complex I-Associated Hydrogen Peroxide Production Is Decreased and Electron Transport Chain Enzyme Activities Are Altered in n-3 Enriched fat-1 Mice

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    The polyunsaturated nature of n-3 fatty acids makes them prone to oxidative damage. However, it is not clear if n-3 fatty acids are simply a passive site for oxidative attack or if they also modulate mitochondrial reactive oxygen species (ROS) production. The present study used fat-1 transgenic mice, that are capable of synthesizing n-3 fatty acids, to investigate the influence of increases in n-3 fatty acids and resultant decreases in the n-6∶n-3 ratio on liver mitochondrial H2O2 production and electron transport chain (ETC) activity. There was an increase in n-3 fatty acids and a decrease in the n-6∶n-3 ratio in liver mitochondria from the fat-1 compared to control mice. This change was largely due to alterations in the fatty acid composition of phosphatidylcholine and phosphatidylethanolamine, with only a small percentage of fatty acids in cardiolipin being altered in the fat-1 animals. The lipid changes in the fat-1 mice were associated with a decrease (p<0.05) in the activity of ETC complex I and increases (p<0.05) in the activities of complexes III and IV. Mitochondrial H2O2 production with either succinate or succinate/glutamate/malate substrates was also decreased (p<0.05) in the fat-1 mice. This change in H2O2 production was due to a decrease in ROS production from ETC complex I in the fat-1 animals. These results indicate that the fatty acid changes in fat-1 liver mitochondria may at least partially oppose oxidative stress by limiting ROS production from ETC complex I
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