256 research outputs found

    A morphometric methodology to assess planktonic foraminiferal response to environmental perturbations: the case study of Oceanic Anoxic Event 2, Late Cretaceous

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    Dwarfism of planktonic foraminiferal specimens is recognised across several intervals subject to globally extended environmental disturbances such as the Cretaceous/Palaeogene boundary and the latest Cenomanian-earliest Turonian Oceanic Anoxic Event 2 (OAE 2) in the Late Cretaceous. However, the occurrence of dwarfed specimens is generally based on the observation of a decrease in the size of specimens at the stereomicroscope without acquiring morphometric data. This approach prevents from assessing the inter-sample morphometric variation of species, reconstructing species-specific trends, and comparing data from different localities to extrapolate global from local signals. We present herein a first step toward the development of a morphometry-based methodology to assess planktonic foraminiferal response to past environmental perturbations. To perform this study, we selected OAE 2 as a target event and we focused on two species, Rotalipora cushmani (Morrow, 1934) and Whiteinella brittonensis (Loeblich & Tappan, 1961), commonly occurring in the assemblages and likely having different palaeoecological preferences. Specimens analysed are from Eastbourne (England), Clot Chevalier (SE France), and Tarfaya (core S57, Morocco). For both species, we measured selected shell parameters (i.e., the number of chambers in the last whorl, the maximum diameter and the height of the test). Our study suggests that the maximum diameter across the first chamber of the inner whorl visible in spiral view is the simplest and most objective methodology to estimate shell size variation in trochospiral planktonic foraminifera, and that this morphometric parameter is likely the most sensitive to the Cenomanian-Turonian environmental disturbances, and thus its variability through time appears worth investigating across other key-stratigraphic intervals. Moreover, this study indicates that the acquisition of morphometric data is required to accurately reconstruct planktonic foraminiferal response to environmental perturbations, because specimen dimensions show high inter-sample variability and based on the data collected in this study they do not experience the predicted size reduction

    Effects of neoadjuvant trastuzumab, pertuzumab and palbociclib on Ki67 in HER2 and ER-positive breast cancer

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    The crosstalk between estrogen and HER2 receptors and cell-cycle regulation sustains resistance to endocrine therapy of HER2- and hormone receptor-positive breast cancer. We earlier reported that women with HER2 and ER-positive breast cancer receiving neoadjuvant dual HER2-block and palbociclib in the NA-PHER2 trial had Ki67 decrease and 27% pathological complete responses (pCR). We extended NA-PHER2 to Cohort B using dual HER2-block and palbociclib without fulvestrant and report here Ki67 drops at week-2 (mean change 1225.7), at surgery (after 16 weeks, mean change 129.5), high objective response (88.5%) and pCR (19.2%). In Cohort C [Ki67 > 20% and HER2low (IHC 1+/2+ without gene amplification)], women also received fulvestrant, had dramatic Ki67 drop at week 2 ( 1229.5) persisting at surgery ( 1219.3), and objective responses in 78.3%. In view of the favorable tolerability and of the efficacy-predictive value of Ki67 drop at week-2, the chemotherapy-free approach of NA-PHER2 deserves further investigation in HER2 and ER-positive breast cancer. The trial is registered with ClinicalTrials.gov, number NCT02530424

    Single Institution trial of anthracycline- and taxane-based chemotherapy for operable breast cancer: The ASTER study

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    The efficacy of anthracycline- and taxane-based chemotherapy for perioperative treatment of breast cancer (BC) has been established. No superiority of a cytotoxic regimen has been demonstrated, provided that administration of an anthracycline and a taxane is warranted. The ASTER study was designed to investigate the safety of 6 months of perioperative chemotherapy with Doxorubicin and Paclitaxel, followed by Cyclophosphamide, Methotrexate, and 5-Fluorouracil. ASTER enrolled patients with cT2-3 N0-1 or pT1-2 N1-3 BC, from November 2008 to August 2011. Treatment consisted of Doxorubicin 60 mg/sm, Paclitaxel 200 mg/sm q21 (AT) for three cycles followed by Cyclophosphamide 600 mg/sm, Methotrexate 40 mg/sm, 5-Fluorouracil 600 mg/sm d1,8 q28 (CMF) for three cycles, in either neo-adjuvant or adjuvant setting. All HER-positive patients received targeted therapy with Trastuzumab for 1 year. Disease-free and overall survival (DFS and OS, respectively) were estimated according to Kaplan-Meier method. Three hundred and thirty patients were enrolled, where 77.9% of cases were treated in an adjuvant setting; 65.5% received breast conservative surgery, 72.4% axillary dissection. 75.5% of cases presented estrogen receptor positivity, 66.7% progesterone receptor positivity; 18.5% of patients presented HER2-positive BC, 16.1% triple negative disease. Twenty-eight (8.5%) developed grade III-IV hematologic toxicity; nine patients (2.7%) developed grade III neurological toxicity. Loco-regional DFS was 99.6% at 1 year, 97.1% at 5 years, 95.9% at 7 years. Corresponding distant DFS was 98.4%, 90.2%, and 88.8%. One, 5, and 7-year OS was 99.6%, 94.9%, and 91.2%, respectively. Chemotherapy with ATx3 -> CMFx3 is confirmed safe and effective at 6.7 years follow-up. These results appear comparable to those reported in regulatory trials of most commonly prescribed anthracycline and taxane-based regimens

    Hypothesis: Induced angiogenesis after surgery in premenopausal node-positive breast cancer patients is a major underlying reason why adjuvant chemotherapy works particularly well for those patients

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    BACKGROUND: We suggest that surgical extirpation of primary breast cancer among other effects accelerates relapse for some premenopausal node-positive patients. These accelerated relapses occur within 10 months of surgery for untreated patients. The mechanism proposed is a stimulation of angiogenesis for distant dormant micrometastases. This has been suggested as one of the mechanisms to explain the mammography paradox for women aged 40–49 years. We could imagine that it also plays a role in adjuvant chemotherapy effectiveness since, perhaps not coincidentally, this is most beneficial for premenopausal node-positive patients. HYPOTHESIS: We speculate that there is a burst of angiogenesis of distant dormant micrometastases after surgery in approximately 20% of premenopausal node-positive patients. We also speculate that this synchronizes them into a temporal highly chemosensitive state and is the underlying reason why adjuvant chemotherapy works particularly well for that patient category. Furthermore, this may explain why cancer in younger patients is more often 'aggressive'. TESTING THE HYPOTHESIS: Stimulation of dormant micrometastases by primary tumor removal is known to occur in animal models. However, we need to determine whether it happens in breast cancer. Transient circulating levels of angioactive molecules and serial high-resolution imaging studies of focal angiogenesis might help. IMPLICATIONS: Short-course cytotoxic chemotherapy after surgery has probably reached its zenith, and other strategies, perhaps antiangiogenic methods, are needed to successfully treat more patients. In addition, the hypothesis predicts that early detection, which is designed to find more patients without involved lymph nodes, may not be a synergistic strategy with adjuvant chemotherapy, which works best with positive lymph node patients

    Secondary malignant neoplasms, progression-free survival and overall survival in patients treated for Hodgkin lymphoma: A systematic review and meta-analysis of randomized clinical trials

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    Treatment intensification to maximize disease control and reduced intensity approaches to minimize the risk of late sequelae have been evaluated in newly diagnosed Hodgkin lymphoma. The influence of these interventions on the risk of secondary malignant neoplasms, progression-free survival and overall survival is reported in the meta-analysis herein, based on individual patient data from 9498 patients treated within 16 randomized controlled trials for newly diagnosed Hodgkin lymphoma between 1984 and 2007. Secondary malignant neoplasms were meta-analyzed using Peto\ue2\u80\u99s method as time-to-event outcomes. For progression-free and overall survival, hazard ratios derived from each trial using Cox regression were combined by inverse-variance weighting. Five study questions (combined-modality treatment vs. chemotherapy alone; more extended vs. involved-field radiotherapy; radiation at higher doses vs. radiation at 20 Gy; more vs. fewer cycles of the same chemotherapy protocol; standard-dose chemotherapy vs. intensified chemotherapy) were investigated. After a median follow-up of 7.4 years, dose-intensified chemotherapy resulted in better progression-free survival rates (P=0.007) as compared with standard-dose chemotherapy, but was associated with an increased risk of therapy-related acute myeloid leukemia/myelodysplastic syndromes (P=0.0028). No progression-free or overall survival differences were observed between combined-modality treatment and chemotherapy alone, but more secondary malignant neoplasms were seen after combined-modality treatment (P=0.010). For the remaining three study questions, outcomes and secondary malignancy rates did not differ significantly between treatment strategies. The results of this meta-analysis help to weigh up efficacy and secondary malignancy risk for the choice of first-line treatment for Hodgkin lymphoma patients. However, final conclusions regarding secondary solid tumors require longer follow-up

    Systematically missing confounders in individual participant data meta-analysis of observational cohort studies.

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    One difficulty in performing meta-analyses of observational cohort studies is that the availability of confounders may vary between cohorts, so that some cohorts provide fully adjusted analyses while others only provide partially adjusted analyses. Commonly, analyses of the association between an exposure and disease either are restricted to cohorts with full confounder information, or use all cohorts but do not fully adjust for confounding. We propose using a bivariate random-effects meta-analysis model to use information from all available cohorts while still adjusting for all the potential confounders. Our method uses both the fully adjusted and the partially adjusted estimated effects in the cohorts with full confounder information, together with an estimate of their within-cohort correlation. The method is applied to estimate the association between fibrinogen level and coronary heart disease incidence using data from 154,012 participants in 31 cohort

    BIOCHAR SURFACE PROPERTIES THROUGH APPLICATION OF AN INNOVATIVE NMR TECHNIQUE: FAST FIELD CYCLING RELAXOMETRY

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    Biochar is a carbonaceous material obtained by pyrolysis of biomass feedstocks. It is applied to soils in order to improve fertility and mitigate greenhouse-gases emissions. In fact, from the one hand, biochar changes physical-chemical soil properties, thereby affecting soil fertility. From the other hand, biochar is resistant to chemical and biochemical degradation. For this reason, its use allows carbon sequestration in soils and consequent reduction of carbon dioxide to the atmosphere. Here, dynamics of water at the liquid-solid interface of water saturated biochars is discussed. Results revealed that water dynamics is affected by the nature of biochar parent biomasses. Moreover, biochar chemical physical properties are affected by conditions for their production. It was understood that water undergoes to an inner-sphere interaction mechanism with biochar surface through formation of weak unconventional hydrogen bonds. Recognition of the interaction mechanisms between water and biochar is of paramount importance in order to understand why biochar soil amendments improve soil fertility and crop production
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