74 resultados para Recurrence theorem


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The main curative therapy for patients with nonsmall cell lung cancer is surgery. Despite this, the survival rate is only 50%, therefore it is important to more efficiently diagnose and predict prognosis for lung cancer patients. Raman spectroscopy is useful in the diagnosis of malignant and premalignant lesions. The aim of this study is to investigate the ability of Raman microscopy to diagnose lung cancer from surgically resected tissue sections, and predict the prognosis of these patients. Tumor tissue sections from curative resections are mapped by Raman microscopy and the spectra analzsed using multivariate techniques. Spectra from the tumor samples are also compared with their outcome data to define their prognostic significance. Using principal component analysis and random forest classification, Raman microscopy differentiates malignant from normal lung tissue. Principal component analysis of 34 tumor spectra predicts early postoperative cancer recurrence with a sensitivity of 73% and specificity of 74%. Spectral analysis reveals elevated porphyrin levels in the normal samples and more DNA in the tumor samples. Raman microscopy can be a useful technique for the diagnosis and prognosis of lung cancer patients receiving surgery, and for elucidating the biochemical properties of lung tumors. (C) 2010 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3323088]

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Keloid scars are common benign fibroproliferative reticular dermal lesions with unknown etiology and ill-defined management with high rate of recurrence post surgery. The progression of keloids is characterized by increased deposition of extracellular matrix proteins, invasion into the surrounding healthy skin and inflammation. Fibroblasts are considered to be the key cellular mediators of fibrogenesis in keloid scars. Fibroblast activation protein alpha (FAP-a) and dipeptidyl peptidase IV (DPPIV) are proteases located at the plasma membrane promoting cell invasiveness and tumor growth and have been previously associated with keloid scars. Therefore, in this study we analyzed in further detail the expression of FAP-a in keloid fibroblasts compared to control skin fibroblasts. Dermal fibroblasts were obtained from punch-biopsies from the active margin of four keloids and four control skin samples. Flow cytometry was used to analyze FAP-a expression and the CytoSelect(®) 24-Well Collagen I Cell Invasion Assay was applied to study fibroblast invasion. Secretion of extracellular matrix (ECM) proteins was investigated by multiplexed particle-based flow cytometric assay and enzyme-linked immunosorbent assay. We found an increased expression of FAP-a in keloid fibroblasts compared to control skin fibroblasts (p

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This paper studies a problem of dynamic pricing faced by a retailer with limited inventory, uncertain about the demand rate model, aiming to maximize expected discounted revenue over an infinite time horizon. The retailer doubts his demand model which is generated by historical data and views it as an approximation. Uncertainty in the demand rate model is represented by a notion of generalized relative entropy process, and the robust pricing problem is formulated as a two-player zero-sum stochastic differential game. The pricing policy is obtained through the Hamilton-Jacobi-Isaacs (HJI) equation. The existence and uniqueness of the solution of the HJI equation is shown and a verification theorem is proved to show that the solution of the HJI equation is indeed the value function of the pricing problem. The results are illustrated by an example with exponential nominal demand rate.

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The classification of protein structures is an important and still outstanding problem. The purpose of this paper is threefold. First, we utilize a relation between the Tutte and homfly polynomial to show that the Alexander-Conway polynomial can be algorithmically computed for a given planar graph. Second, as special cases of planar graphs, we use polymer graphs of protein structures. More precisely, we use three building blocks of the three-dimensional protein structure-alpha-helix, antiparallel beta-sheet, and parallel beta-sheet-and calculate, for their corresponding polymer graphs, the Tutte polynomials analytically by providing recurrence equations for all three secondary structure elements. Third, we present numerical results comparing the results from our analytical calculations with the numerical results of our algorithm-not only to test consistency, but also to demonstrate that all assigned polynomials are unique labels of the secondary structure elements. This paves the way for an automatic classification of protein structures.

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Objective: We describe a 4-generation family with familial medullary thyroid carcinoma (FMTC) - a variant of multiple endocrine neoplasia type 2 (MEN 2) without extra-thyroid features. RET mutation analysis confirmed an E768D mutation in exon 13 in 8 family members, 3 affected with medullary thyroid cancer alone while the other 5 were detected to be mutation carriers. This mutation has been described in very few families worldwide and the spectrum of disease and natural history is unclear. Results: Three affected members had medullary thyroid cancer (MTC) confirmed histologically at ages 25, 50 and 56 years, respectively. The E768D mutation appears to have a less aggressive clinical course compared to other high risk RET mutations with no evidence of clinical recurrence up to I I years after initial therapy. Of five gene carriers identified, two are asymptomatic at the age of 70 and 61, and three had raised calcitonin levels at 46, 39, and 45 years. Following total thyroidectomy, one gene carrier had a histologically normal thyroid at age 46, following a mildly elevated calcitonin, one had C-cell hyperplasia at the age of 39, and one had a frank focus of carcinoma in the left thyroid lobe at the age of 45. No members had evidence of phaeochromocytoma or parathyroid disease on screening. Conclusion: The RET E768D mutation is associated with MTC with a later age at presentation, incomplete penetrance and less aggressive course compared with other high risk RET mutations. To date in this family the E768D mutation has not been associated with either phaeochromocytoma or hyperparathyroidism. The appropriate screening strategy for and management of E768D carriers is difficult reflecting the phenotypic heterogeneity.

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The reduced Whitehead group $\SK$ of a graded division algebra graded by a torsion-free abelian group is studied. It is observed that the computations here are much more straightforward than in the non-graded setting. Bridges to the ungraded case are then established by the following two theorems: It is proved that $\SK$ of a tame valued division algebra over a henselian field coincides with $\SK$ of its associated graded division algebra. Furthermore, it is shown that $\SK$ of a graded division algebra is isomorphic to $\SK$ of its quotient division algebra. The first theorem gives the established formulas for the reduced Whitehead group of certain valued division algebras in a unified manner, whereas the latter theorem covers the stability of reduced Whitehead groups, and also describes $\SK$ for generic abelian crossed products.

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Background: The long-term effects of adjuvant polychemotherapy regimens in oestrogen-receptor-poor (ER-poor) breast cancer, and the extent to which these effects are modified by age or tamoxifen use, can be assessed by an updated meta-analysis of individual patient data from randomised trials. Methods: Collaborative meta-analyses of individual patient data for about 6000 women with ER-poor breast cancer in 46 trials of polychemotherapy versus not (non-taxane-based polychemotherapy, typically about six cycles; trial start dates 1975-96, median 1984) and about 14 000 women with ER-poor breast cancer in 50 trials of tamoxifen versus not (some trials in the presence and some in the absence of polychemotherapy; trial start dates 1972-93, median 1982). Findings: In women with ER-poor breast cancer, polychemotherapy significantly reduced recurrence, breast cancer mortality, and death from any cause, in those younger than 50 years and those aged 50-69 years at entry into trials of polychemotherapy versus not. In those aged younger than 50 years (1907 women, 15% node-positive), the 10-year risks were: recurrence 33% versus 45% (ratio of 10-year risks 0·73, 2p<0·00001), breast cancer mortality 24% versus 32% (ratio 0·73, 2p=0·0002), and death from any cause 25% versus 33% (ratio 0·75, 2p=0·0003). In women aged 50-69 years (3965 women, 58% node-positive), the 10-year risks were: recurrence 42% versus 52% (ratio 0·82, 2p<0·00001), breast cancer mortality 36% versus 42% (ratio 0·86, 2p=0·0004), and death from any cause 39% versus 45% (ratio 0·87, 2p=0·0009). Few were aged 70 years or older. Tamoxifen had little effect on recurrence or death in women who were classified in these trials as having ER-poor disease, and did not significantly modify the effects of polychemotherapy. Interpretation: In women who had ER-poor breast cancer, and were either younger than 50 years or between 50 and 69 years, these older adjuvant polychemotherapy regimens were safe (ie, had little effect on mortality from causes other than breast cancer) and produced substantial and definite reductions in the 10-year risks of recurrence and death. Current and future chemotherapy regimens could well yield larger proportional reductions in breast cancer mortality.

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Object
Trigeminal neuralgia pain causes severe disability. Stereotactic radiosurgery is the least invasive surgical option for patients with trigeminal neuralgia. Since different medical and surgical options have different rates of pain relief and morbidity, it is important to evaluate longer-term outcomes.

Methods
The authors retrospectively reviewed outcomes in 503 medically refractory patients with trigeminal neuralgia who underwent Gamma Knife surgery (GKS). The median patient age was 72 years (range 26–95 years). Prior surgery had failed in 205 patients (43%). The GKS typically was performed using MR imaging guidance, a single 4-mm isocenter, and a maximum dose of 80 Gy.

Results
Patients were evaluated for up to 16 years after GKS; 107 patients had > 5 years of follow-up. Eighty-nine percent of patients achieved initial pain relief that was adequate or better, with or without medications (Barrow Neurological Institute [BNI] Scores I–IIIb). Significant pain relief (BNI Scores I–IIIa) was achieved in 73% at 1 year, 65% at 2 years, and 41% at 5 years. Including Score IIIb (pain adequately controlled with medication), a BNI score of I–IIIb was found in 80% at 1 year, 71% at 3 years, 46% at 5 years, and 30% at 10 years. A faster initial pain response including adequate and some pain relief was seen in patients with trigeminal neuralgia without additional symptoms, patients without prior surgery, and patients with a pain duration of = 3 years. One hundred ninety-three (43%) of 450 patients who achieved initial pain relief reported some recurrent pain 3–144 months after initial relief (median 50 months). Factors associated with earlier pain recurrence that failed to maintain adequate or some pain relief were trigeminal neuralgia with additional symptoms and = 3 prior failed surgical procedures. Fifty-three patients (10.5%) developed new or increased subjective facial paresthesias or numbness and 1 developed deafferentation pain; these symptoms resolved in 17 patients. Those who developed sensory loss had better long-term pain control (78% at 5 years).

Conclusions
Gamma Knife surgery proved to be safe and effective in the treatment of medically refractory trigeminal neuralgia and is of value for initial or recurrent pain management. Despite the goal of minimizing sensory loss with this procedure, some sensory loss may improve long-term outcomes. Pain relapse is amenable to additional GKS or another procedure.

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Flutter prediction as currently practiced is usually deterministic, with a single structural model used to represent an aircraft. By using interval analysis to take into account structural variability, recent work has demonstrated that small changes in the structure can lead to very large changes in the altitude at which
utter occurs (Marques, Badcock, et al., J. Aircraft, 2010). In this follow-up work we examine the same phenomenon using probabilistic collocation (PC), an uncertainty quantification technique which can eficiently propagate multivariate stochastic input through a simulation code,
in this case an eigenvalue-based fluid-structure stability code. The resulting analysis predicts the consequences of an uncertain structure on incidence of
utter in probabilistic terms { information that could be useful in planning
flight-tests and assessing the risk of structural failure. The uncertainty in
utter altitude is confirmed to be substantial. Assuming that the structural uncertainty represents a epistemic uncertainty regarding the
structure, it may be reduced with the availability of additional information { for example aeroelastic response data from a flight-test. Such data is used to update the structural uncertainty using Bayes' theorem. The consequent
utter uncertainty is significantly reduced across the entire Mach number range.

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Objective: The research aimed to determine the extent to which illness cognitions and coping explain psychological distress (fear of cancer recurrence, anxiety and depression symptoms) among family carers of survivors of oesophageal cancer.


Methods: Carers of patients registered with the Oesophageal Patients' Association in the UK were mailed a questionnaire booklet containing questions about medical and demographic variables, the Illness Perception Questionnaire-Revised, the Cancer Coping Questionnaire, the Concerns about Recurrence Scale and the Hospital Anxiety and Depression Scale.


Results: Complete responses were received from 382 family carers (75% male; mean (SD) age=62 (10.91) years). Regression models indicated that the variables measured could explain between 35 and 49% of the variance in psychological distress among carers. Illness cognitions (particularly perceptions of the cause of, consequences of and personal control over oesophageal cancer and the carer's understanding of the condition) explained the majority of this variance. Positive focus coping strategies were also found to be important in explaining psychological distress.


Conclusion: The results of this study are consistent with previous research demonstrating that illness cognitions are significant correlates of adaptive outcomes, thereby suggesting that cognition-based interventions could potentially be effective in minimizing emotional distress among family carers of oesophageal cancer survivors.

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Purpose: Current prognostic factors are poor at identifying patients at risk of disease recurrence after surgery for stage II colon cancer. Here we describe a DNA microarray-based prognostic assay using clinically relevant formalin-fixed paraffin-embedded (FFPE) samples. Patients and Methods: A gene signature was developed from a balanced set of 73 patients with recurrent disease (high risk) and 142 patients with no recurrence (low risk) within 5 years of surgery. Results: The 634-probe set signature identified high-risk patients with a hazard ratio (HR) of 2.62 (P <.001) during cross validation of the training set. In an independent validation set of 144 samples, the signature identified high-risk patients with an HR of 2.53 (P <.001) for recurrence and an HR of 2.21 (P = .0084) for cancer-related death. Additionally, the signature was shown to perform independently from known prognostic factors (P <.001). Conclusion: This gene signature represents a novel prognostic biomarker for patients with stage II colon cancer that can be applied to FFPE tumor samples. © 2011 by American Society of Clinical Oncology.

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Objective: To investigate the association between angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) and disease progression and survival in cancer patients.

Methods: Using terms for cancer and ACEIs/ARBs, MEDLINE, EMBASE and Web of Science were systematically searched for observational/interventional studies that used clinically relevant outcomes for cancer progression and survival.

Results: Ten studies met the inclusion criteria. Two studies showed a significant improvement in overall survival (OS) with ACEI/ARB use among patients with advanced pancreatic (HR 0.52, 95% CI 0.29–0.88) and non-small cell lung cancer (HR 0.56, 95% CI 0.33–0.95). An improvement in progression-free survival (PFS) was also reported for pancreatic cancer patients (HR 0.58, 95% CI 0.34–0.95) and patients with renal cell carcinoma (HR 0.54, p = 0.02). ACEI/ARB use was protective against breast cancer recurrence (HR 0.60, 95% CI 0.37–0.96), colorectal cancer distant metastasis (OR 0.22, 95% CI 0.08–0.65) and prostate specific antigen (PSA) failure in prostate cancer patients (p = 0.034). One study observed a worse OS (HR 2.01, 95% CI 1.00–4.05) and PFS in ACEI users with multiple myeloma (p = 0.085) while another reported an increased risk of breast cancer recurrence (HR = 1.56, 95% CI 1.02–2.39).

Conclusion: There is some evidence to suggest that ACEI or ARB use may be associated with improved outcomes in cancer patients. Larger, more robust studies are required to explore this relationship further.

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Distributions of source intensity in two dimensions (designated the source model), averaged over a single laser pulse, based on experimental measurements of spatial coherence, are considered for radiation from the unresolved 23.2/23.6 nm spectral lines from the germanium collisional X-ray laser. The model derives from measurements of the visibility of Young slit interference fringes determined by a method based on the Wiener-Khinchin theorem. Output from amplifiers comprising three and four target elements have similar coherence properties in directions within the horizontal plane corresponding to strong plasma refraction effects and fitting the coherence data shows source dimensions (FWHM) are similar to 26 mu m (horizontal), significantly smaller than expected by direct imaging, and similar to 125 mu m (vertical: equivalent to the height of the driver excitation). (C) 1999 Elsevier Science B.V. All rights reserved.

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We present measurements of the transverse and longitudinal coherence lengths of the fourth harmonic of a 1053-nm, 2.5-ps laser generated during high-intensity (up to 10(19) W cm(-2)) interactions with a solid target. Coherence lengths were measured by use of a Young's double-slit interferometer. The effective source size, as defined by the Van Cittert-Zernicke theorem, was found to be 10-12 mu m, and the coherence time was observed to be in the range 0.02-0.4 ps.