Diseases Commons^™

Accumulation Of Phycotoxins In The Mussel Mytilus Galloprovincialis From The Central Adriatic Sea, Maja Pavela-Vrančić, Ivana Ujević, Živana Ninčević Gladan, Ambrose Furey

Physical Sciences Publications

Surveys of DSP (Diarrheic Shellfish Poisoning) toxin profiles in the mussel Mytilus galloprovincialis from coastal waters of the central Adriatic Sea, over the years 1995 to 2001, demonstrate that incidents of shellfish toxicity in this area are dominated by the occurrence of okadaic acid (OA) and a PTX derivative, 7-epi-pectenotoxin-2-seco acid (7-epi-PTX-2SA). Toxin composition and the relative ratio of toxic components in shellfish is in correlation with the occurrence of DSP producing organisms from the Dinophysis species along with Prorocentrum micans and Lingulodinium polyedrum. The occurrence of D. sacculus shortly before the appearance of OA in shellfish implicates its possible …

Sheep Updates 2006 - Part 4, K. G. Geenty, A. A. Swan, A. J. Smith, J. L. Smith, Chris Oldham, R. G. Woodgate, R. A. Love, E. Dobbe, H. M. Hoult, J. Pearson, S. Hill, A. Van Burgel, R. B. Besier, R. Warburton, L. Mathwin, D. Rogers, E. Crossley, Allan Herbert, P. Nichols, Tony Albertsen, Darryl Mcclements, Graeme Martin, Penny Hawken, Caroline Vinoles, Beth Paganoni, Dominique Blanche

Sheep Updates

This session covers seven papers from different authors:

MANAGEMENT

1. Wool and meat traits in Merino flocks in different regions, K.G. Geenty, A.A. Swan, A.J. Smith, J.L. Smith, Sheep CRC and CSIRO Livestock Industries, Armidale

2. Fat score or Condition score? - It all depends on what you want to do! Chris Oldham, Department of Agriculture and Food Western Australia

3. Sheep worm control - the latest for Western Australia, RG Woodgate, RA Love, E Dobbe, HM Hoult, J Pearson, S Hill, A van Burgel and RB Besier, Department of Agriculture and Food Western Australia

PASTURES

4. Rethinking pasture production …

Different Public Health Interventions Have Varying Effects, Paula Diehr, Anne B. Newman, Liming Cai, Ann Derleth

UW Biostatistics Working Paper Series

Objective: To compare performance of one-time health interventions to those that change the probability of transitioning from one health state to another. Study Design and Setting: We used multi-state life table methods to estimate the impact of eight types of interventions on several outcomes. Results: In a cohort beginning at age 65, curing all the sick persons at baseline would increase life expectancy by 0.23 years and increase years of healthy life by .54 years. An equal amount of improvement could be obtained with a 12% decrease in the probability of getting sick, a 16% increase in the probability of …

Regression Analysis For The Partial Area Under The Roc Curve, Tianxi Cai, Lori E. Dodd

Harvard University Biostatistics Working Paper Series

No abstract provided.

Optimal Therapy Regimens For Treatment-Resistant Mutations Of Hiv, Weiqing Gu, Helen Moore

All HMC Faculty Publications and Research

In this paper, we use control theory to determine optimal treatment regimens for HIV patients, taking into account treatment-resistant mutations of the virus. We perform optimal control analysis on a model developed previously for the dynamics of HIV with strains of various resistance to treatment (Moore and Gu, 2005). This model incorporates three types of resistance to treatments: strains that are not responsive to protease inhibitors, strains not responsive to reverse transcriptase inhibitors, and strains not responsive to either of these treatments. We solve for the optimal treatment regimens analytically and numerically. We find parameter regimes for which optimal dosing …

Introduction To N-Adaptive Fuzzy Models To Analyze Public Opinion On Aids, Florentin Smarandache, W.B. Vasantha Kandasamy

Branch Mathematics and Statistics Faculty and Staff Publications

“AIDS is not simply a physical malady, it is also an artifact of social and sexual transgression, violated taboo, fractured identity—political and personal projections. Its key words are primarily the property of the powerful. AIDS: Keywords – is my attempt to identify and contest some of the assumptions underlying our current ‘knowledge’. In this effort I am joined by many AIDS activists including people living with AIDS— Acquired Immuno Deficiency Syndrome. “A syndrome is a pattern of symptoms pointing to a “morbid state” which may or may not be caused by infectious agents; a disease, on the other hand is, …

Model Checking For Roc Regression Analysis, Tianxi Cai, Yingye Zheng

Harvard University Biostatistics Working Paper Series

The Receiver Operating Characteristic (ROC) curve is a prominent tool for characterizing the accuracy of continuous diagnostic test. To account for factors that might invluence the test accuracy, various ROC regression methods have been proposed. However, as in any regression analysis, when the assumed models do not fit the data well, these methods may render invalid and misleading results. To date practical model checking techniques suitable for validating existing ROC regression models are not yet available. In this paper, we develop cumulative residual based procedures to graphically and numerically assess the goodness-of-fit for some commonly used ROC regression models, and …

Is The Number Of Sick Persons In A Cohort Constant Over Time?, Paula Diehr, Ann Derleth, Anne Newman, Liming Cai

UW Biostatistics Working Paper Series

Objectives: To estimate the number of persons in a cohort who are sick, over time.

Methods: We calculated the number of sick persons in the Cardiovascular Health Study (CHS), a cohort study of older adults followed up to 14 years, using eight definitions of “healthy” and “sick”. We projected the number in each health state over time for a birth cohort.

Results: The number of sick persons in CHS was approximately constant for 14 years, for all definitions of “sick”. The estimated number of sick persons in the birth cohort was approximately constant from ages 55-75, after which it decreased. …

Weast Nile Virus Serosurveillance In Iowa White-Tailed Deer (1999-2003), Julian Santatella, Robert Mclean, Jeffrey S. Hall, James S. Gill, Richard A. Bowen, Harlo H. Hadow, Larry Clark

United States Department of Agriculture Wildlife Services: Staff Publications

Sera from white-tailed deer (Odocoileus virginianus) were collected in Iowa during the winter months (1999-2003), 2 years before and after West Nile virus (WNV) was first reported in Iowa (2001), and were analyzed for antibodies to WNV. Samples from 1999 to 2001 were antibody negalive by blocking enzyme-linikedI immunosorbent assay (bELISA) and plaque reduction neutralization test (PRNT₉₀). Prevalence derived from bELISA (2002, 12.7%; 2003. 11.2%) and WNV PRNT₉₀ (2002,7.9%; 2003, 8.5%) assays were similar. All sanlples were negative for antibodies against St. Louis encephalitis virus as determined by PRNT₉₀. Antibodies to flaviviruses were …

Prognosis Of Stage Ii Colon Cancer By Non-Neoplastic Mucosa Gene Expresssion Profiling, Alain Barrier, Sandrine Dudoit, Et Al.

U.C. Berkeley Division of Biostatistics Working Paper Series

Aims. This study assessed the possibility to build a prognosis predictor, based on non-neoplastic mucosa microarray gene expression measures, in stage II colon cancer patients. Materials and Methods. Non-neoplastic colonic mucosa mRNA samples from 24 patients (10 with a metachronous metastasis, 14 with no recurrence) were profiled using the Affymetrix HGU133A GeneChip. The k-nearest neighbor method was used for prognosis prediction using microarray gene expression measures. Leave-one-out cross-validation was used to select the number of neighbors and number of informative genes to include in the predictor. Based on this information, a prognosis predictor was proposed and its accuracy estimated by …

Colon Cancer Prognosis Prediction By Gene Expression Profiling, Alain Barrier, Sandrine Dudoit, Et Al.

U.C. Berkeley Division of Biostatistics Working Paper Series

Aims. This study assessed the possibility to build a prognosis predictor, based on microarray gene expression measures, in stage II and III colon cancer patients. Materials and Methods. Tumour (T) and non-neoplastic mucosa (NM) mRNA samples from 18 patients (9 with a recurrence, 9 with no recurrence) were profiled using the Affymetrix HGU133A GeneChip. The k-nearest neighbour method was used for prognosis prediction using T and NM gene expression measures. Six-fold cross-validation was applied to select the number of neighbours and the number of informative genes to include in the predictors. Based on this information, one T-based and one NM-based …

The Sensitivity And Specificity Of Markers For Event Times, Tianxi Cai, Margaret S. Pepe, Thomas Lumley, Yingye Zheng, Nancy Swords Jenny

Harvard University Biostatistics Working Paper Series

No abstract provided.

A Mathematical Model For Treatment-Resistant Mutations Of Hiv, Helen Moore, Weiqing Gu

All HMC Faculty Publications and Research

In this paper, we propose and analyze a mathematical model, in the form of a system of ordinary differential equations, governing mutated strains of human immunodeficiency virus (HIV) and their interactions with the immune system and treatments. Our model incorporates two types of resistant mutations: strains that are not responsive to protease inhibitors, and strains that are not responsive to reverse transcriptase inhibitors. It also includes strains that do not have either of these two types of resistance (wild-type virus) and strains that have both types. We perform our analysis by changing the system of ordinary differential equations (ODEs) to …

Convergence Analysis Of Mcmc Method In The Study Of Genetic Linkage With Missing Data, Diana Fisher

Theses, Dissertations and Capstones

Computational infeasibility of exact methods for solving genetic linkage analysis problems has led to the development of a new collection of stochastic methods, all of which require the use of Markov chains. The purpose of this work is to investigate the complexities of missing data in pedigree analysis using the Monte Carlo Markov Chain (MCMC) method as compared to the exact results. Also, we attempt to determine an association between missing data in a familial pedigree and the convergence to stationarity of a descent graph Markov chain implemented in the stochastic method for parametric linkage analysis.

In particular, we will …

Bayesian Hierarchical Distributed Lag Models For Summer Ozone Exposure And Cardio-Respiratory Mortality, Yi Huang, Francesca Dominici, Michelle L. Bell

Johns Hopkins University, Dept. of Biostatistics Working Papers

In this paper, we develop Bayesian hierarchical distributed lag models for estimating associations between daily variations in summer ozone levels and daily variations in cardiovascular and respiratory (CVDRESP) mortality counts for 19 U.S. large cities included in the National Morbidity Mortality Air Pollution Study (NMMAPS) for the period 1987 - 1994.

At the first stage, we define a semi-parametric distributed lag Poisson regression model to estimate city-specific relative rates of CVDRESP associated with short-term exposure to summer ozone. At the second stage, we specify a class of distributions for the true city-specific relative rates to estimate an overall effect by …

Multiple Testing And Data Adaptive Regression: An Application To Hiv-1 Sequence Data, Merrill D. Birkner, Sandra E. Sinisi, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

Analysis of viral strand sequence data and viral replication capacity could potentially lead to biological insights regarding the replication ability of HIV-1. Determining specific target codons on the viral strand will facilitate the manufacturing of target specific antiretrovirals. Various algorithmic and analysis techniques can be applied to this application. We propose using multiple testing to find codons which have significant univariate associations with replication capacity of the virus. We also propose using a data adaptive multiple regression algorithm to obtain multiple predictions of viral replication capacity based on an entire mutant/non-mutant sequence profile. The data set to which these techniques …

Inside Unlv, Diane Russell, Carol C. Harter, Cate Weeks, Cayrn Key

Inside UNLV

No abstract provided.

A Hypothesis Test For The End Of A Common Source Outbreak, Ron Brookmeyer, Xiaojun You

Johns Hopkins University, Dept. of Biostatistics Working Papers

The objective of this paper is to develop a hypothesis testing procedure to determine whether a common source outbreak has ended. We do not assume that the calendar date of exposure to the pathogen is known. We assume an underlying parametric model for the incubation period distribution of a 2-paramter exponential model with a guarantee time, although the parameters are not assumed to be known. The hypothesis testing procedure is based on the spacings between ordered calendar dates of disease onset of the cases. A simulation study was performed to evaluate the robustness of the methods to a lognormal model …

Effect Of Misreported Family History On Mendelian Mutation Prediction Models, Hormuzd A. Katki

Johns Hopkins University, Dept. of Biostatistics Working Papers

People with familial history of disease often consult with genetic counselors about their chance of carrying mutations that increase disease risk. To aid them, genetic counselors use Mendelian models that predict whether the person carries deleterious mutations based on their reported family history. Such models rely on accurate reporting of each member's diagnosis and age of diagnosis, but this information may be inaccurate. Commonly encountered errors in family history can significantly distort predictions, and thus can alter the clinical management of people undergoing counseling, screening, or genetic testing. We derive general results about the distortion in the carrier probability estimate …

Psychological Factors Associated With Anticipatory Nausea And Vomiting, Melinda L. Nielsen

Loma Linda University Electronic Theses, Dissertations & Projects

Many cancer patients experience adverse chemotherapy-related side effects. The present study examined the relationships among disease variables (i.e. stage of cancer, type of breast cancer), medical treatment variables (i.e. toxicity of chemotherapy regimen, strength of antiemetic treatment), psychological variables (i.e. health locus of control, anxiety sensitivity, desire for control, coping strategies), and anticipatory nausea and vomiting in women with breast cancer. One hundred women with breast cancer completed the Multidimensional Health Locus of Control Scale - Form C, the Anxiety Sensitivity Index, the Krantz Health Opinion Survey, the Coping Inventory for Stressful Situations, and the Morrow Assessment of Nausea and …

Inside Unlv, Cate Weeks, Carol C. Harter, Diane Russell, Holly Ivy De Vore

Inside UNLV

No abstract provided.

Agribusiness Sheep Updates - 2004 Part 2, Anyou Liu, Clinton Revell, Phil Nichols, Brad Nutt, Darryl Clements, Lucy Anderton, Stephen Gherardi, Chris Oldham, Paul Sanford, John Gladman, G. E. Donald, A. Edirisinghe, D. A. Henry, S. P. Gittins, R. C. G. Smith, Roy Butler, Kelly Pearce, David Masters, David Pethick, Andrew Thompson, Ken Hart, Johan Greeff, Beth Paganoni, Rachel Kirby, Matt Ryan, Kira Butler, Roger Heggarty, David Hopkins, Samantha Giles, Tom Plaisted, Mark Ferguson, Darren Gordon, John Young, Sandra Brown, Ian Mcfarland, John Archer, John Milton, Rob Davidson, Graeme Martin, David Lindsay, Johnathan England, Mandy Curnow, Karina P. Wood, Ashley K. White, B. Lloyd Davies, Paul M. Carberry, Mark Hyder, Mike Freer, Andrew Van Burgel, Kazue Tanaka, Andrew Peterson, Roger Wiese, Gonzalo Mata, Evan Burt, Amanda Miller, Anne Bennett, Felicity Flugge, Amir Abadi, Perry Dolling, Dean Thomas, Mike Ewing, David Lindsay, Emma Kopke, E. A. Dowling, E. K. Crossley, Brien (Ben) E. Norton, John Karlsson, Geoff Pollott, Diana Fedorenko, Darryl Clements, Robert Beard, Brown Besier, Una Ryan, Caroline Bath

Sheep Updates

Precision Pastures

Using Species Diversity to Improve Pasture Performance Anyou Liu and Clinton Revell, Department of Agriculture, Western Australia

New Annual Pasture Legumes for Sheep Graziers Phil Nichols, Angelo Loi, Brad Nutt and Darryl McClements Department of Agriculture Western Australia

Pastures from Space – Can Satellite Estimates of Pasture Growth Rate be used to Increase Farm Profit? Lucy Anderton, Stephen Gherardi and Chris Oldham Department of Agriculture Western Australia

Summer-active Perennial Grasses for Profitable Sheep Production Paul Sanford and John Gladman, Department of Agriculture, Western Australia

Pastures From Space – Validation Of Predictions Of Pasture Growth Rates DONALD, G.E^{.A …}

Inside Unlv, Holly Ivy De Vore, Carol C. Harter, Stuart Mann

Inside UNLV

No abstract provided.

Nonparametric And Semiparametric Inference For Models Of Tumor Size And Metastasis, Debashis Ghosh

The University of Michigan Department of Biostatistics Working Paper Series

There has been some recent work in the statistical literature for modelling the relationship between the size of primary cancers and the occurrences of metastases. While nonparametric methods have been proposed for estimation of the tumor size distribution at which metastatic transition occurs, their asymptotic properties have not been studied. In addition, no testing or regression methods are available so that potential confounders and prognostic factors can be adjusted for. We develop a unified approach to nonparametric and semiparametric analysis of modelling tumor size-metastasis data in this article. An equivalence between the models considered by previous authors with survival data …

Individualized Predictions Of Disease Progression Following Radiation Therapy For Prostate Cancer., Jeremy Taylor, Menggang Yu, Howard M. Sandler

The University of Michigan Department of Biostatistics Working Paper Series

Background: Following treatment for localized prostate cancer, men are monitored with serial PSA measurements. Refining the predictive value of post-treatment PSA determinations may add to clinical management and we have developed a model that predicts for an individual patient future PSA values and estimates the time to future clinical recurrence.

Methods: Data from 934 patients treated for prostate cancer between 1987 and 2000 were used to develop a comprehensive statistical model to fit the clinical recurrence events and pattern of PSA data. A logistic regression model was used for the probability of cure, non-linear hierarchical mixed models were used for …

Individual Prediction In Prostate Cancer Studies Using A Joint Longitudinal-Survival-Cure Model, Menggang Yu, Jeremy Taylor, Howard M. Sandler

The University of Michigan Department of Biostatistics Working Paper Series

For monitoring patients treated for prostate cancer, Prostate Specific Antigen (PSA) is measured periodically after they receive treatment. Increases in PSA are suggestive of recurrence of the cancer and are used in making decisions about possible new treatments. The data from studies of such patients typically consist of longitudinal PSA measurements, censored event times and baseline covariates. Methods for the combined analysis of both longitudinal and survival data have been developed in recent years, with the main emphasis being on modeling and estimation. We analyze data from a prostate cancer study that has been extended by adding a mixture structure …

Evaluating The Disparity Of Female Breast Cancer Mortality Among Racial Groups - A Spatiotemporal Analysis, Chiehwen E. Hsu, Holly Jacobson, Francisco Soto Mas

Faculty, Staff and Student Publications

Background The literature suggests that the distribution of female breast cancer mortality demonstrates spatial concentration. There remains a lack of studies on how the mortality burden may impact racial groups across space and over time. The present study evaluated the geographic variations in breast cancer mortality in Texas females according to three predominant racial groups (non-Hispanic White, Black, and Hispanic females) over a twelve-year period. It sought to clarify whether the spatiotemporal trend might place an uneven burden on particular racial groups, and whether the excess trend has persisted into the current decade.

Methods The Spatial Scan Statistic was employed …

Optimization Of Breast Cancer Screening Modalities, Yu Shen, Giovanni Parmigiani

Johns Hopkins University, Dept. of Biostatistics Working Papers

Mathematical models and decision analyses based on microsimulations have been shown to be useful in evaluating relative merits of various screening strategies in terms of cost and mortality reduction. Most investigations regarding the balance between mortality reduction and costs have focused on a single modality, mammography. A systematic evaluation of the relative expenses and projected benefit of combining clinical breast examination and mammography is not at present available. The purpose of this report is to provide methodologic details including assumptions and data used in the process of modeling for complex decision analyses, when searching for optimal breast cancer screening strategies …

Modeling The Incubation Period Of Anthrax, Ron Brookmeyer, Elizabeth Johnson, Sarah Barry

Johns Hopkins University, Dept. of Biostatistics Working Papers

Models of the incubation period of anthrax are important to public health planners because they can be used to predict the delay before outbreaks are detected, the size of an outbreak and the duration of time that persons should remain on antibiotics to prevent disease. The difficulty is that there is little direct data about the incubation period in humans. The objective of this paper is to develop and apply models for the incubation period of anthrax. Mechanistic models that account for the biology of spore clearance and germination are developed based on a competing risks formulation. The models predict …

Cross-Calibration Of Stroke Disability Measures: Bayesian Analysis Of Longitudinal Ordinal Categorical Data Using Negative Dependence, Giovanni Parmigiani, Heidi W. Ashih, Gregory P. Samsa, Pamela W. Duncan, Sue Min Lai, David B. Matchar

Johns Hopkins University, Dept. of Biostatistics Working Papers

It is common to assess disability of stroke patients using standardized scales, such as the Rankin Stroke Outcome Scale (RS) and the Barthel Index (BI). The Rankin Scale, which was designed for applications to stroke, is based on assessing directly the global conditions of a patient. The Barthel Index, which was designed for general applications, is based on a series of questions about the patient’s ability to carry out 10 basis activities of daily living. As both scales are commonly used, but few studies use both, translating between scales is important in gaining an overall understanding of the efficacy of …