891 resultados para Grade retention
Resumo:
Core biopsy is an increasingly used technique in the pre-operative diagnosis of breast carcinoma, as it provides useful prognostic information with respect to tumour type and grade. Neoadjuvant chemotherapy is being used in the treatment of large and locally advanced breast cancers but little is known regarding the correlation between tumour histology on pre-treatment core biopsy and that in residual tumour following primary chemotherapy and surgery. This study aimed to evaluate the accuracy of core biopsy in predicting these features in patients treated with primary chemotherapy. One hundred and thirty-three patients with carcinoma of the breast diagnosed on clinical, radiological and cytological examination underwent core biopsy, followed by primary chemotherapy (with cyclophosphamide, vincristine, doxorubicin and prednisolone) and surgery. The false-negative rate for pre-treatment core biopsy was 14%, with 91% agreement between the grade demonstrated on core biopsy and that in the residual tumour following completion of chemotherapy. Tumour type in the residual post-chemotherapy tumour was predicted by core biopsy in 84%. This study suggests that pre-treatment core biopsy histology accurately predicts residual tumour histology following primary chemotherapy and surgery in patients with breast cancer. (C) 2002 Elsevier Science Ltd. All rights reserved.
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The relationship between retention loss in single crystal PbTiO3 ferroelectric thin films and leakage currents is demonstrated by piezoresponse and conductive atomic force microscopy measurements. It was found that the polarization reversal in the absence of an electric field followed a stretched exponential behavior 1-exp[-(t/k)(d)] with exponent d>1, which is distinct from a dispersive random walk process with d <. The latter has been observed in polycrystalline films for which retention loss was associated with grain boundaries. The leakage current indicates power law scaling at short length scales, which strongly depends on the applied electric field. Additional information of the microstructure, which contributes to an explanation of the presence of leakage currents, is presented with high resolution transmission electron microscopy analysis.
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Aim: This paper is a report of a study to examine the role of personality and self-efficacy in predicting academic performance and attrition in nursing students.
Background: Despite a considerable amount of research investigating attrition in nursing students and new nurses, concerns remain. This particular issue highlights the need for a more effective selection process whereby those selected are more likely to complete their preregistration programme successfully, and remain employed as Registered Nurses.
Method: A longitudinal design was adopted. A questionnaire, which included measures of personality and occupational and academic self-efficacy, was administered to 384 students early in the first year of the study. At the end of the programme, final marks and attrition rates were obtained from university records for a total of 350 students. The data were collected from 1999 to 2002.
Findings: Individuals who scored higher on a psychoticism scale were more likely to withdraw from the programme. Occupational self-efficacy was revealed to be a statistically significant predictor of final mark obtained, in that those with higher self-efficacy beliefs were more likely to achieve better final marks. Extraversion was also shown to negatively predict academic performance in that those with higher extraversion scores were more likely to achieve lower marks.
Conclusion: More research is needed to explore the attributes of successful nursing students and the potential contribution of psychological profiling to a more effective selection process.
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The optimisation of Fe and Al oxyhydroxide materials produced using industrial grade coagulants is presented in this work. The effects of synthesis pH and post-synthesis washing procedure onto the arsenic adsorption capacity of the materials were investigated. It was shown that the materials produced at higher pH were more efficient in removing As(V), especially after cleaning procedure. The materials produced at lower pH were less efficient in removing As(V) but the higher presence of sulphate groups in the materials produced at lower pH enhanced As(III) adsorption. Most performing materials can remove up to 84.7 mg As(V) g-1 or 77.9 mg As(III) g-1.
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Bonded-in rod connections in timber possess many desirable attributes in terms of efficiency, manufacture, performance, aesthetics and cost. In recent years research has been conducted on such connections using fibre reinforced polymers (FRPs) as an alternative to steel. This research programme investigates the pull-out capacity of Basalt FRP rods bonded-in in low grade Irish Sitka Spruce. Embedded length is thought to be the most influential variable contributing to pull- out capacity of bonded-in rods after rod diameter. Previous work has established an optimum embedded length of 15 times the hole diameter. However, this work only considered the effects of axial stress on the bond using a pull-compression testing system which may have given an artificially high pull out capacity as bending effects were neglected. A hinge system was utilised that allows the effects of bending force to be taken in to consideration along with axial forces in a pull-out test. This paper describes an experimental programme where such pull-bending tests were carried out on samples constructed of 12mm diameter BFRP bars with a 2mm glueline thickness and embedded lengths between 80mm and 280mm bonded-in to low-grade timber with an epoxy resin. Nine repetitions of each were tested. A clear increase in pull-out strength was found with increasing embedded length.
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OBJECTIVES: Barrett’s esophagus (BE) is a common premalignant lesion for which surveillance is recommended. This strategy is limited by considerable variations in clinical practice. We conducted an international, multidisciplinary, systematic search and evidence-based review of BE and provided consensus recommendations for clinical use in patients with nondysplastic, indefinite, and low-grade dysplasia (LGD). METHODS: We defined the scope, proposed statements, and searched electronic databases, yielding 20,558 publications that were screened, selected online, and formed the evidence base. We used a Delphi consensus process, with an 80% agreement threshold, using GRADE (Grading of Recommendations Assessment, Development and Evaluation) to categorize the quality of evidence and strength of recommendations. RESULTS: In total, 80% of respondents agreed with 55 of 127 statements in the final voting rounds. Population endoscopic screening is not recommended and screening should target only very high-risk cases of males aged over 60 years with chronic uncontrolled reflux. A new international definition of BE was agreed upon. For any degree of dysplasia, at least two specialist gastrointestinal (GI) pathologists are required. Risk factors for cancer include male gender, length of BE, and central obesity. Endoscopic resection should be used for visible, nodular areas. Surveillance is not recommended for <5 years of life expectancy. Management strategies for indefinite dysplasia (IND) and LGD were identified, including a de-escalation strategy for lower-risk patients and escalation to intervention with follow-up for higher-risk patients. CONCLUSIONS: In this uniquely large consensus process in gastroenterology, we made key clinical recommendations for the escalation/de-escalation of BE in clinical practice. We made strong recommendations for the prioritization of future research.
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Two ionic liquids, 1-ethylpyridinium docusate (IL1) and tri-n-butyl(2-hydroxyethyl)phosphonium docusate (IL2), were designed and synthesized with the explicit intention of imparting a combination of plasticization and antimicrobial efficacy when incorporated into medical grade poly(vinyl chloride)s (PVCs). The glass transition (T-g) of PVC can be reduced by >20 degrees C on addition of 15 wt% IL2. Both IL1 and IL2 leached to varying extents from the base PVC resins rendering the surface of the PVCs hydrophilic. The antimicrobial activity of both ILs is related to the presence and concentration of both cationic and anionic component of the ILs leached from the PVC and inversely proportional to the extent of PVC gelation. Blends of the PVCs with IL1 displayed antibacterial activity against almost all Gram-positive bacteria tested, including coagulase-negative Staphylococci (CoNS) and methicillin-resistant Staphylococcus aureus (MRSA), but not with IL2 at low concentration in contrast to our previous study when high concentrations of IL2 were used. The more hydrophilic IL1 when added to PVC retards biofilm formation.
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Cells experience damage from exogenous and endogenous sources that endanger genome stability. Several cellular pathways have evolved to detect DNA damage and mediate its repair. Although many proteins have been implicated in these processes, only recent studies have revealed how they operate in the context of high-ordered chromatin structure. Here, we identify the nuclear oncogene SET (I2PP2A) as a modulator of DNA damage response (DDR) and repair in chromatin surrounding double-strand breaks (DSBs). We demonstrate that depletion of SET increases DDR and survival in the presence of radiomimetic drugs, while overexpression of SET impairs DDR and homologous recombination (HR)-mediated DNA repair. SET interacts with the Kruppel-associated box (KRAB)-associated co-repressor KAP1, and its overexpression results in the sustained retention of KAP1 and Heterochromatin protein 1 (HP1) on chromatin. Our results are consistent with a model in which SET-mediated chromatin compaction triggers an inhibition of DNA end resection and HR.
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AIMS: To determine whether Abl immunoreactivity correlates with grade and cell kinetics (apoptosis and mitosis) in chondrosarcoma.
METHODS: Sections from 16 chondrosarcomas were stained immunohistochemically using a polyclonal antibody to the c-Abl/Bcr-Abl oncoprotein. Apoptotic indices and mitotic indices were assessed in all tumours. Sections from 24 paraffin wax blocks of human fetal rib (gestational ages, 15-42 weeks) were also stained to determine whether the Abl protein is synthesised consistently throughout endochondral ossification.
RESULTS: Abl staining in immature fetal rib chondrocytes at all stages of development was predominantly nuclear, and 70% of cells showed moderate to strong staining. Abl immunoreactivity was minimal or absent in hypertrophic chondrocytes about to undergo apoptosis at the growth plate. There was strong Abl staining in grade 1 and grade 2 chondrosarcomas but staining was greatly reduced or absent in grade 3 chondrosarcomas. There was a very significant linear correlation between apoptotic index (mean, 0.68%; range, 0-3.2%) and mitotic index (mean, 0.23%; range, 0-0.9%), and both indices were significantly lower in grade 1 than in grade 2 and grade 3 chondrosarcomas.
CONCLUSIONS: These data suggest that abl gene expression is associated with differentiation and apoptosis inhibition in fetal and neoplastic chondrocytes. However, these putative effects cannot be ascribed solely to the Abl protein, because several additional factors contribute to the regulation of both differentiation and apoptosis.
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Higher expression of the miR-433 microRNA (miRNA) is associated with poorer survival outcomes in patients with HGSOC that may be overcome by a greater understanding of the functional role of this miRNA. We previously described miR-433 as a critical cell cycle regulator and mediator of cellular senescence. Downregulation of the mitotic arrest deficiency 2 (MAD2) protein by miR-433 led to increased cellular resistance to paclitaxel in epithelial ovarian cancer cells (EOC). Furthermore immunohistochemical (IHC) analysis of MAD2 expression in patients with HGSOC showed that loss of MAD2 was significantly associated with poorer patient survival. Higher miR-433 expression is also associated with an increased resistance to the platins which is unrelated to loss of MAD2 expression. In silico analysis of the miR-433 target proteins in the TCGA database identified the association between a number of miR-433 targets and poorer patient survival. IHC analysis of the miR-433 target, histone deacetylase 6 (HDAC6), confirmed that its expression was significantly associated with a decrease in patient overall survival. The knock-down of HDAC6 by siRNA in EOC cells did not attenuate apoptotic responses to paclitaxel or platin although lower endogenous HDAC6 expression was associated with more resistant EOC cell lines. In vitro analysis revealed that EOC cells which survived chemotherapeutic kill with high doses of paclitaxel expressed higher miR-433 and concomitant decreased expression of the miR-433 targets. These cells were more chemoresistant compared to the parental cell line and repopulated as 3d organoid cultures in non-adherent stem cell selective conditions; thus indicating that the cells which survive chemotherapy were viable, capable of regrowth and had an increased potential for pluripotency. In conclusion, our data suggests that chemotherapy is not driving the transcriptional upregulation of miR-433 but rather selecting a population of cells with high miR-433 expression that may contribute to chemoresistant disease and tumour recurrence.