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Search Results: 1 - 10 of 85600 matches for " Randall W. Burt "
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Extra-Abdominal Desmoid Tumors Associated with Familial Adenomatous Polyposis
George T. Calvert,Michael J. Monument,Randall W. Burt,Kevin B. Jones,R. Lor Randall
Sarcoma , 2012, DOI: 10.1155/2012/726537
Abstract: Extra-abdominal desmoid tumors are a significant cause of morbidity in patients with familial adenomatous polyposis syndrome. Understanding of the basic biology and natural history of these tumors has increased substantially over the past decade. Accordingly, medical and surgical management of desmoid tumors has also evolved. This paper analyzes recent evidence pertaining to the epidemiology, molecular biology, histopathology, screening, and treatment of extra-abdominal desmoid tumors associated with familial adenomatous polyposis syndrome.
Extra-Abdominal Desmoid Tumors Associated with Familial Adenomatous Polyposis
George T. Calvert,Michael J. Monument,Randall W. Burt,Kevin B. Jones,R. Lor Randall
Sarcoma , 2012, DOI: 10.1155/2012/726537
Abstract: Extra-abdominal desmoid tumors are a significant cause of morbidity in patients with familial adenomatous polyposis syndrome. Understanding of the basic biology and natural history of these tumors has increased substantially over the past decade. Accordingly, medical and surgical management of desmoid tumors has also evolved. This paper analyzes recent evidence pertaining to the epidemiology, molecular biology, histopathology, screening, and treatment of extra-abdominal desmoid tumors associated with familial adenomatous polyposis syndrome. 1. Introduction Desmoid tumors (DTs), also known as aggressive fibromatosis, are fibroblastic neoplasms which are often locally aggressive but lack metastatic potential. They may occur sporadically or in association with familial adenomatous polyposis (FAP) syndrome. Among individuals with FAP, desmoids most frequently occur in intra-abdominal and abdominal wall locations with most arising from the peritoneum. These abdominal desmoids range in severity from indolent, asymptomatic lesions to highly invasive, sometimes fatal tumors. Although less common than abdominal desmoids and very rarely fatal, extra-abdominal desmoids are also a significant cause of morbidity in this population. This paper will review recent developments in the diagnosis, screening, treatment, and prognosis of FAP-associated extra-abdominal DTs. 2. Epidemiology of FAP-Associated Desmoid Tumors The overall incidence of DTs has frequently been quoted at 2–4 per million people per year [1, 2]. This estimate is derived from a 1986 Finnish study which used the pathologic records of several regional hospitals and their known catchment area populations to calculate an incidence figure [3]. Recently, the Dutch national pathology database was analyzed, and 519 total desmoid cases in patients over the age of ten were identified from 1999 to 2009. There were 480 sporadic DTs and 39 FAP-DTs. The annual incidence was 3.7 per million overall [4] consistent with the earlier Finnish study. The same nationwide study from The Netherlands identified 1400 patients over the age of ten with FAP during the 1999 to 2009 period. FAP-associated DTs (FAP-DTs) made up 7.5% of all DTs, and the relative risk of an FAP patient developing a DT was over 800-fold higher than the general population [4]. The Dutch study was limited by the use of pathologic specimens as many DTs may be identified based upon history, physical exam, and imaging but not biopsied or surgically excised especially in the FAP cohort. Additionally, some individuals with sporadic DTs may have had as yet
Mutation-negative FAP patients with mRNA defects of APC
Condie Michelle W,Tuohy Therese MF,Shires Patricia,Burt Randall W
Hereditary Cancer in Clinical Practice , 2010, DOI: 10.1186/1897-4287-8-s1-o1
Abstract:
RNA Sequencing of Sessile Serrated Colon Polyps Identifies Differentially Expressed Genes and Immunohistochemical Markers
Don A. Delker, Brett M. McGettigan, Priyanka Kanth, Stelian Pop, Deborah W. Neklason, Mary P. Bronner, Randall W. Burt, Curt H. Hagedorn
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088367
Abstract: Background Sessile serrated adenomas/polyps (SSA/Ps) may account for 20–30% of colon cancers. Although large SSA/Ps are generally recognized phenotypically, small (<1 cm) or dysplastic SSA/Ps are difficult to differentiate from hyperplastic or small adenomatous polyps by endoscopy and histopathology. Our aim was to define the comprehensive gene expression phenotype of SSA/Ps to better define this cancer precursor. Results RNA sequencing was performed on 5′ capped RNA from seven SSA/Ps collected from patients with the serrated polyposis syndrome (SPS) versus eight controls. Highly expressed genes were analyzed by qPCR in additional SSA/Ps, adenomas and controls. The cellular localization and level of gene products were examined by immunohistochemistry in syndromic and sporadic SSA/Ps, adenomatous and hyperplastic polyps and controls. We identified 1,294 differentially expressed annotated genes, with 106 increased ≥10-fold, in SSA/Ps compared to controls. Comparing these genes with an array dataset for adenomatous polyps identified 30 protein coding genes uniquely expressed ≥10-fold in SSA/Ps. Biological pathways altered in SSA/Ps included mucosal integrity, cell adhesion, and cell development. Marked increased expression of MUC17, the cell junction protein genes VSIG1 and GJB5, and the antiapoptotic gene REG4 were found in SSA/Ps, relative to controls and adenomas, were verified by qPCR analysis of additional SSA/Ps (n = 21) and adenomas (n = 10). Immunohistochemical staining of syndromic (n≥11) and sporadic SSA/Ps (n≥17), adenomatous (n≥13) and hyperplastic (n≥10) polyps plus controls (n≥16) identified unique expression patterns for VSIG1 and MUC17 in SSA/Ps. Conclusion A subset of genes and pathways are uniquely increased in SSA/Ps, compared to adenomatous polyps, thus supporting the concept that cancer develops by different pathways in these phenotypically distinct polyps with markedly different gene expression profiles. Immunostaining for a subset of these genes differentiates both syndromic and sporadic SSA/Ps from adenomatous and hyperplastic polyps.
Activating mutation in MET oncogene in familial colorectal cancer
Deborah W Neklason, Michelle W Done, Nykole R Sargent, Ann G Schwartz, Hoda Anton-Culver, Constance A Griffin, Dennis J Ahnen, Joellen M Schildkraut, Gail E Tomlinson, Louise C Strong, Alexander R Miller, Jill E Stopfer, Randall W Burt
BMC Cancer , 2011, DOI: 10.1186/1471-2407-11-424
Abstract: MET exons were amplified by PCR from germline DNA of 148 affected sibling pairs with colorectal cancer. Amplicons with altered sequence were detected with high-resolution melt-curve analysis using a LightScanner (Idaho Technologies). Samples demonstrating alternative melt curves were sequenced. A TaqMan assay for the specific c.2975C > T change was used to confirm this mutation in a cohort of 299 colorectal cancer cases and to look for allelic amplification in tumors.Here we report a germline non-synonymous change in the MET proto-oncogene at amino acid position T992I (also reported as MET p.T1010I) in 5.2% of a cohort of sibling pairs affected with CRC. This genetic variant was then confirmed in a second cohort of individuals diagnosed with CRC and having a first degree relative with CRC at prevalence of 4.1%. This mutation has been reported in cancer cells of multiple origins, including 2.5% of colon cancers, and in <1% in the general population. The threonine at amino acid position 992 lies in the tyrosine kinase domain of MET and a change to isoleucine at this position has been shown to promote metastatic behavior in cell-based models. The average age of CRC diagnosis in patients in this study is 63 years in mutation carriers, which is 8 years earlier than the general population average for CRC.Although the MET p.T992I genetic mutation is commonly found in somatic colorectal cancer tissues, this is the first report also implicating this MET genetic mutation as a germline inherited risk factor for familial colorectal cancer. Future studies on the cancer risks associated with this mutation and the prevalence in different at-risk populations will be an important extension of this work to define the clinical significance.Colorectal cancer (CRC) is one of the more familial of cancers, and the presence of a family history of this malignancy is a well established risk factor. Twin studies suggest inherited and/or familial factors contribute to 25-35% of CRC cases [1].
SWAT and Wavelet Analysis for Understanding the Climate Change Impact on Hydrologic Response  [PDF]
Shesh Raj Koirala, Randall W. Gentry
Open Journal of Modern Hydrology (OJMH) , 2012, DOI: 10.4236/ojmh.2012.22006
Abstract: Quantifying the hydrological response to an increased atmospheric carbon dioxide concentration and climate change is important in a watershed scale particularly from the application point of view. The specific objectives are to evaluate the climate change impact on the future water yield at the outlet of Clinch River Watershed upstream of Norris Lake in Tennessee, USA and see how the frequency of extreme water yield (e.g. flood) changes compared to present condition. The predicted future climate change by climate change scenarios A2 from community climate system model (CCSM) is applied. The model was calibrated using monthly average streamflow data from 1970 to 1989 and validated using similar data from 1990 to 2009 collected at a USGS gauging station 03528000. Changes in monthly average streamflow were estimated for long term (around 2099). Results were also interpreted in the time-frequency domain approach by showing how frequency of occurrence changes based on A2 scenario.
Long-Term Data from Fields Recovering after Sugarcane, Banana, and Pasture Cultivation in Ecuador
Randall W. Myster
Dataset Papers in Science , 2013, DOI: 10.7167/2013/468973
Abstract: I report here on an ongoing permanent plot study in areas recovering from agriculture in Ecuador. These plots were set up in 1995 at Maquipucuna Reserve where the forest is tropical lower montane. The study consists of replicate fields in three past crop types (Sugarcane, Banana, and Pasture) for a total of six fields. Each field was first divided into 25 continuous 2?m × 5?m subplots which together form a 10?m × 25?m plot with the longest side bordering the adjacent forest. Then starting in 1996, and continuing annually every year since, each subplot has been sampled for percent cover of all plants and diameter at breast height (dbh) for all trees whose dbh is greater than or equal to 1?cm. I have used that data in these published studies: (1) species composition and life form, richness, and basal area trends, (2) computation of all positive and negative pairwise species associations, (3) relationships between richness and productivity over time, (4) dominance-diversity curves, and (5) definition and quantification of old field plant communities. Finally with the help of the LTER program in Puerto Rico, this sampling continues, with 2012 marking the sixteenth year of continuous annual sampling. 1. Introduction Conducted for decades over many of the most common gradients on earth, studies of succession after agriculture—also called postagricultural or old field succession—have helped ecologists gain insights into the processes that structure plant communities and into the role of history and initial conditions in community development [1, 2]. Examination of old fields has led to the rise of important ecological theories, such as the initial floristic composition hypothesis [3] and the resource ratio hypothesis [4]. Using permanent plots [5] established at abandonment as the backbone of old field research (e.g., the Buell-Small old field plot study in New Jersey, USA [6, 7]), scientists have been successful in finding the pattern of response over time after abandonment from crops [8] and in discovering many of the mechanisms that determine the pattern [9, 10]. Furthermore, studies of postagricultural succession have provided a framework for comparison and evaluation of various theories of succession and community development [11]. A considerable amount of old field and pasture research has taken place in the temperate regions of the United States [4, 6, 9, 12–16] and Europe [15, 16]. The recovery of agricultural areas, however, is vital to ecosystems all over the world [17], where they form ecotones between forest and grasslands [18]. Particularly in the
Kink-Based Path Integral Calculations of Atoms He-Ne
Randall W. Hall
Physics , 2002, DOI: 10.1016/S0009-2614(02)01115-6
Abstract: An adaptive, kink-based path integral formalism is used to calculate the ground state energies of the atoms He-Ne. The method uses an adaptive scheme to virtually eliminate the sign difficulties. This is done by using a Monte Carlo scheme to identify states that contribute significantly to the canonical partition function and then include them in the wavefunctions to calculate the canonical averages. The calculations use the 6-31G basis set and obtain both precision and accuracy.
An Adaptive, Kink-Based Approach to Path Integral Calculations
Randall W. Hall
Physics , 2001, DOI: 10.1063/1.1423939
Abstract: A kink-based expression for the canonical partition function is developed using Feynman's path integral formulation of quantum mechanics and a discrete basis set. The approach is exact for a complete set of states. The method is tested on the 3x3 Hubbard model and overcomes the sign problem seen in traditional path integral studies of fermion systems. Kinks correspond to transitions between different N-electron states, much in the same manner as occurs in configuration interaction calculations in standard ab initio methods. The different N-electron states are updated, based on which states occur frequently during a Monte Carlo simulation, giving better estimates of the true eigenstates of the Hamiltonian.
Simulation of geometric and electronic degrees of freedom using a kink-based path integral formulation: application to molecular systems
Randall W. Hall
Physics , 2005, DOI: 10.1063/1.1884945
Abstract: A kink-based path integral method, previously applied to atomic systems, is modified and used to study molecular systems. The method allows the simultaneous evolution of atomic and electronic degrees of freedom. Results for CH$_4 $, NH$_3 $, and H$_2 $O demonstrate this method to be accurate for both geometries and energies. Comparison with DFT and MP2 level calculations show the path integral approach to produce energies in close agreement with MP2 energies and geometries in close agreement with both DFT and MP2 results.
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