79 research outputs found
Fixed Effect Estimation of Large T Panel Data Models
This article reviews recent advances in fixed effect estimation of panel data
models for long panels, where the number of time periods is relatively large.
We focus on semiparametric models with unobserved individual and time effects,
where the distribution of the outcome variable conditional on covariates and
unobserved effects is specified parametrically, while the distribution of the
unobserved effects is left unrestricted. Compared to existing reviews on long
panels (Arellano and Hahn 2007; a section in Arellano and Bonhomme 2011) we
discuss models with both individual and time effects, split-panel Jackknife
bias corrections, unbalanced panels, distribution and quantile effects, and
other extensions. Understanding and correcting the incidental parameter bias
caused by the estimation of many fixed effects is our main focus, and the
unifying theme is that the order of this bias is given by the simple formula
p/n for all models discussed, with p the number of estimated parameters and n
the total sample size.Comment: 40 pages, 1 tabl
The impact of GGH -401C>T polymorphism on cisplatin-based chemoradiotherapy response and survival in cervical cancer
Uncorrected proofAims: Cervical cancer is the third most frequent cancer in women worldwide, mostly treated with cisplatin-based chemoradiotherapy. Since it is known that folate metabolism might interfere with cisplatin effectiveness, we intended to study the influence of the Gamma Glutamyl Hydrolase -401C > T polymorphism in treatment response in cervical cancer.
Methods: We retrospectively reviewed the clinical data of 167 patients with bulky cervical cancer submitted to cisplatin-based chemoradiotherapy. The genotypes of GGH -401C > T SNP were determined by real-time PCR and statistical analysis was performed by chi(2) test and survival analysis.
Results: The genotypes of GGH-401C > T were significantly associated with the response to platinum-based chemoradiotherapy. Treatment response was higher in patients carrying the CC genotype, who presented a significant increased chance of treatment response (survival time in months/genotype: 91 for CC Vs 72 for CT/TT; p = 0.035, log rank test). A Cox regression analysis accordingly showed that the presence of the T allele was significantly linked to a worse treatment response (HR = 3.036; CI 95% 1.032-8.934, p = 0.044).
Conclusions: The results of our study suggested the potential interest of GGH -401C > T as a predictive factor of the outcome of cervical carcinoma treated with cisplatin-based chemoradiotherapy. (c) 2012 Elsevier B.V. All rights reserved.The authors thank the Liga Portuguesa Contra o Cancro - Centro Regional do Norte (LPCC - Portuguese League against Cancer). We gratefully acknowledge the funding of this work by the Minister of Health of Portugal (Comissao de Fomento da Investigacao em Cuidados de Saude)
CONCORDE: A phase I platform study of novel agents in combination with conventional radiotherapy in non-small-cell lung cancer
Lung cancer is the leading cause of cancer mortality worldwide and most patients are unsuitable for ‘gold standard’ treatment, which is concurrent chemoradiotherapy. CONCORDE is a platform study seeking to establish the toxicity profiles of multiple novel radiosensitisers targeting DNA repair proteins in patients treated with sequential chemoradiotherapy. Time-to-event continual reassessment will facilitate efficient dose-finding.
Abbreviations
ATM: Ataxia telangiectasia mutated
ATR: Ataxia telangiectasia and Rad3 related
cfDNA: Cell-free DNA
CRT: Chemoradiotherapy
CT: Computed tomography
CTCAE: Common terminology criteria for adverse events
CTRad: Clinical and Translational Radiotherapy Research Working Group
DDRi: DNA damage response inhibitor
DLT: Dose limiting toxicity
DNA: Deoxyribonucleic acid
DNA-PK: DNA-dependent protein kinase
ECOG: Eastern Cooperative Oncology Group
EORTC: European Organisation for Research and Treatment of Cancer
ICRU: International Commission on Radiation Units and Measurements
IMPs: Investigational medicinal products
LA: Locally advanced
MRC: Medical Research Council
NCRI: National Cancer Research Institute
NSCLC: Non-small cell lung cancer
PARP: Poly (ADP-ribose) polymerase
PET: Positron emission tomography
PFS: Progression free survival
PROMs: Patient-reported outcome measures
RECIST: Response evaluation criteria in solid tumours
RP2D: Recommended phase II dose
RT: Radiotherapy
SACT: Systemic anti-cancer therapy
SRC: Safety review committee
TiTE-CRM: Time to event continual reassessment method
TNM: Tumour node metastasi
A Proof-Of-Principle Study of Epigenetic Therapy Added to Neoadjuvant Doxorubicin Cyclophosphamide for Locally Advanced Breast Cancer
BACKGROUND: Aberrant DNA methylation and histone deacetylation participate in cancer development and progression; hence, their reversal by inhibitors of DNA methylation and histone deacetylases (HDACs) is at present undergoing clinical testing in cancer therapy. As epigenetic alterations are common to breast cancer, in this proof-of-concept study demethylating hydralazine, plus the HDAC inhibitor magnesium valproate, were added to neoadjuvant doxorubicin and cyclophosphamide in locally advanced breast cancer to assess their safety and biological efficacy. METHODOLOGY: This was a single-arm interventional trial on breast cancer patients (ClinicalTrials.gov Identifier: NCT00395655). After signing informed consent, patients were typed for acetylator phenotype and then treated with hydralazine at 182 mg for rapid-, or 83 mg for slow-acetylators, and magnesium valproate at 30 mg/kg, starting from day –7 until chemotherapy ended, the latter consisting of four cycles of doxorubicin 60 mg/m(2) and cyclophosphamide 600 mg/m(2) every 21 days. Core-needle biopsies were taken from primary breast tumors at diagnosis and at day 8 of treatment with hydralazine and valproate. MAIN FINDINGS: 16 patients were included and received treatment as planned. All were evaluated for clinical response and toxicity and 15 for pathological response. Treatment was well-tolerated. The most common toxicity was drowsiness grades 1–2. Five (31%) patients had clinical CR and eight (50%) PR for an ORR of 81%. No patient progressed. One of 15 operated patients (6.6%) had pathological CR and 70% had residual disease <3 cm. There was a statistically significant decrease in global 5(m)C content and HDAC activity. Hydralazine and magnesium valproate up- and down-regulated at least 3-fold, 1,091 and 89 genes, respectively. CONCLUSIONS: Hydralazine and magnesium valproate produce DNA demethylation, HDAC inhibition, and gene reactivation in primary tumors. Doxorubicin and cyclophosphamide treatment is safe, well-tolerated, and appears to increase the efficacy of chemotherapy. A randomized phase III study is ongoing to support the efficacy of so-called epigenetic or transcriptional cancer therapy
Spectacular horizons: the birth of science fiction film, television, and radio, 1900-1959
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Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study
Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe
Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study
Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research
The importance of environment on respiratory genotype/phenotype relationships in the Inuit
Background: Genetic and environmental influences and their interactions are central to asthma pathogenesis. This study aimed to investigate the effects of different macro-environments on asthma genotype-phenotype associations in two geographically separated populations with common ancestry. Methods: To accomplish this, two unselected populations of Inuit were recruited, one living in Greenland (n = 618) and the other in Denmark (n = 739). Subjects were genotyped for CD14 C-159T, SCGB1A1 A38G, ADRB2 Arg16Gly and Gln27Glu. The resulting genetic data were analysed for relationships with asthma-related parameters including lung function, ever asthma, atopy, rhinitis and dermatitis. Results: The results showed contrasting magnitude and direction of genetic associations between the two geographically separate Inuit populations. In Greenland, the ADRB2 16Arg allele was associated with male-specific lower lung function, but in Denmark the same allele was associated with male-specific higher lung function. This allele was also associated with higher incidence of ever asthma in Denmark but not in Greenland. The SCGB1A1 38A allele was associated with lower rhinitis prevalence in Greenland but not in Denmark. Conclusions: These associations suggest that environment interacts with candidate asthma genes to modulate asthma pathogenesis in the Inuit. © 2009 John Wiley & Sons A/S
DNA-barcoding revela la existencia de un posible nuevo género del complejo <i>Laurencia</i> (Rodophyta, Ceramiales) en Las Islas Canarias
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Les mammites bovines représentent un coût économique et sanitaire important pour la production laitière dans le monde. La prévention et le traitement des mammites reposent essentiellement sur l’usage d’antibiotiques qui affectent négativement la qualité de lait et dont l’efficacité est limitée, en particulier vis-à-vis de Staphylococcus aureus. En outre, l’usage massif d’antibiotiques pour contrôler les mammites contribue au risque de dissémination de l’antibiorésistance. Ces dernières années, l'utilisation de microorganismes probiotiques pour lutter contre les infections suscite un intérêt croissant en santé humaine et animale. Le but de cette étude était d'isoler des bactéries lactiques du microbiote mammaire bovin afin d’évaluer leur potentiel probiotique pour la prévention et le traitement des mammites. L'échantillonnage de l'écosystème du canal du trayon a permisl'isolement de 165 clones appartenant principalement aux genres Enterococcus, Streptococcus, Lactobacillus et Lactococcus. Parmi ces isolats, 11 souches appartenant aux genres non pathogènes Lactobacillus et Lactococcus, et non redondantes d’après leur profil PFGE, ont été retenues pour être caractérisées vis-à-vis deleurs propriétés de surface (hydrophobicité, autoaggrégation), leur capacité à produire des substances antimicrobiennes, leurs capacités d'adhésion et d’internalisation aux cellules épithéliales mammaires bovines MAC-T et leurs propriétés immunomodulatrices. Ce criblage in vitro a permis la sélection de 2 souches de L. brevis et 1 souche de L. plantarum pour leur capacité à coloniser le tissu épithélial mammaire bovin. Lepotentiel immonumodulateur, determiné sur culture cellulaire, a révélé une tendance pro-inflammatoire pour deux souches appartenant aux espèces L. casei et L. brevis et une tendance antiinflammatoire de 2 souches de L. plantarum. Ce travail ouvre de nouvelles perspectives sur le développement de solutions alternatives et durables pour le contrôle des mammites bovines
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