Disease Modeling Commons^™

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 …

Temporal Stability And Geographic Variation In Cumulative Case Fatality Rates And Average Doubling Times Of Sars Epidemics, Alison P. Galvani, Xiudong Lei, Nicholas P. Jewell

U.C. Berkeley Division of Biostatistics Working Paper Series

We analyze temporal stability and geographic trends in cumulative case fatality rates and average doubling times of severe acute respiratory syndrome (SARS). In part, we account for correlations between case fatality rates and doubling times through differences in control measures. We discuss factors that may alter future estimates of case fatality rates. We also discuss reasons for heterogeneity in doubling times among countries and the implications for the control of SARS in different countries and parameterization of epidemic models.

A Computer Model Of Intracranial Pressure Dynamics During Traumatic Brain Injury That Explicitly Models Fluid Flows And Volumes, Wayne W. Wakeland, Brahm Goldstein, Louis Macovsky, James Mcnames

Complex Systems Faculty Publications and Presentations

This report documents a computer model of intracranial pressure (ICP) dynamics that is used to evaluate clinical treatment options for elevated ICP during traumatic brain injury (TBI). The model uses fluid volumes as primary state variables and explicitly models fluid flows as well as the resistance, compliance, and pressure associated with each of the compartments (arteries and arterioles, capillary bed, veins, venous sinus, ventricles, and brain parenchyma). The model has been tested to assure that it reproduces a correct physiologic response to intra-and extra-parenchymal hemorrhage and edema, and to therapies directed at reducing ICP such as cerebral spinal fluid drainage, …

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

UW Biostatistics Working Paper Series

The statistical literature on assessing the accuracy of risk factors or disease markers as diagnostic tests deals almost exclusively with settings where the test, Y, is measured concurrently with disease status D. In practice, however, disease status may vary over time and there is often a time lag between when the marker is measured and the occurrence of disease. One example concerns the Framingham Risk Score as a marker for the future risk of cardiovascular events, events that occur after the score is ascertained. To evaluate such a marker, one needs to take the time lag into account since the …

Comparative Genomic Hybridization Array Analysis, Annette M. Molinaro, Mark J. Van Der Laan, Dan H. Moore

U.C. Berkeley Division of Biostatistics Working Paper Series

At the present time, there is increasing evidence that cancer may be regulated by the number of copies of genes in tumor cells. Through microarray technology it is now possible to measure the number of copies of thousands of genes and gene segments in samples of chromosomal DNA. Microarray comparative genomic hybridization (array CGH) provides the opportunity to both measure DNA sequence copy number gains and losses and map these aberrations to the genomic sequence. Gains can signify the over-expression of oncogenes, genes which stimulate cell growth and have become hyperactive, while losses can signify under-expression of tumor suppressor genes, …

Mathematical Transmission Model Of The Spread Of Hiv Through Sexual Contact And Iv Drug Usage Among Heterosexuals In Western Australia, B. Glockner

Theses : Honours

The human immunodeficiency virus (HIV) and its latter stage, the acquired immune deficiency syndrome (AIDS), are still a major health problem in the world and the full extent of the epidemic is unknown. The HIV virus in Australia has been spread mainly through homosexual contact, but this mode of transmission is decreasing while transmission from heterosexual contact and from IV drug use is increasing. The proposed mathematical model concentrates on transmission of the HIV virus through heterosexual contact and IV drug use among heterosexuals in Western Australia. The model parameters will be estimated from surveys conducted by the Australian National …

Aids: Prophecy And Present Reality, Victor De Gruttola, William Ira Bennett

New England Journal of Public Policy

Mathematical modeling of the AIDS epidemic can be useful for policymakers even though precise projections are not possible at this time. Models are useful in establishing ranges for current and future prevalence of HIV infection and incidence of AIDS, as well as in predicting the effect of a given intervention strategy. Most decision makers are using models implicitly when they use epidemiological information as a basis for policy; formulating a model explicitly permits examination of the underlying assumptions. By creating and testing a variety of models, an investigator can determine whether the models reflect more the underlying assumptions or the …

Developing A Periodontal Screening Examination, Jeffrey R. Morgulis

Loma Linda University Electronic Theses, Dissertations & Projects

Periodontal disease is the primary cause of tooth loss in the adult, and therefore, early diagnosis of periodontal disease by the general practitioner is important in terms of prevention as well as treatment. The present study was designed to develop a periodontal screening examination which would fulfill the following requirements:

1. It should utilize precise and easily understood criteria.
2. It should take a short period of time.
3. It should enable the practitioner to accurately place patients into various disease categories.
4. It should enable the practitioner to easily and quickly relate these disease categories to treatment.

A "comprehensive" periodontal examination was performed …