Shyamal Peddada directs the Statistical Consulting Service (SCS) offered by the Biostatistics Branch to researchers within the Division of Intramural Research (DIR). In addition to using standard statistical methods for analyzing data, as needed, the SCS develops innovative statistical methods that are appropriate for analyzing data. The service works with researchers on study design and analysis of experiments and participates in the preparation of the National Toxicology Program’s technical report series on toxicity and carcinogenicity of various chemicals. It also offers short courses on statistical design and analysis for DIR researchers.
Peddada also conducts methodological research in the field of order restricted inference with applications to toxicology and analysis of gene expression data. He exploits the underlying inequality structure in the data, which generally results in an increased power in the analysis and better interpretation of the data. The statistical methods that Peddada developed have a wide range of applications. For instance, he has developed a new statistical procedure for analyzing NTP's rodent cancer bioassay data that takes into account NTP’s database of relevant historical control data. He is also developing statistical methods for analyzing gene expression data obtained from time-course and dose-response microarray experiments. He recently developed free software called "Order Restricted Inference for Ordered Gene ExpressioN" (ORIOGEN) for analyzing gene expression data obtained from time-course/dose-response studies. ORIOGEN may be downloaded from the Biostatistics Branch Resources page.
Selected Publications
Theory and Methods
Hwang, J. T. G. and Peddada, S. D. (1994). Confidence Interval Estimation Subject to Order Restrictions. Annals of Statistics, 22, 67-93.
Peddada S.. D. and Chang T. C. (1996). Bootstrap Confidence Region Estimation of the Motion of Rigid Bodies. J. of Amer. Statist. Assoc., 81, 231-241.
Peddada, S. D., Prescott, K., and Conaway, M. (2001). Tests for Order Restrictions in Binary Data. Biometrics, 57, 1219-1227. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11764263)
Hoferkamp, C., and Peddada, S. D. (2002). Estimation of parameters in linear models with heteroscedastic variances subject to order restrictions. J. of Multivariate Analysis, 82, 65-87.
Peddada, S. D., Lobenhofer, L., Li. L., Afshari, C., Weinberg, C., and Umbach, D., (2003). Gene selection and clustering for time-course and dose-response microarray experiments using order-restricted inference. Bioinformatics, 19, 834-841. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12724293)
Liu, D., Weinberg, C. and Peddada, S. D. (2004). A geometric approach to determine association and coherence of the activation times of cell-cycling genes under different experimental conditions. Bioinformatics, 20, 2521-2528. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15087309)
Liu, D., Umbach, D., Peddada, S. D., Li, L., Crockett, P., and Weinberg, C. (2004). A Random-Periods Model for Expression of Cell-Cycle Genes. Proc. of National Acad. of Sci., 101, No. 19, 7240-7245. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15123814)
Conaway, M., Dunbar, S., and Peddada, S. D. (2004). Designs for single or multiple agent phase I trials. Biometrics, 60, 661-669. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15339288)
Peddada, S. D., Dinse, G., and Haseman, J. (2005). A survival-adjusted quantal response test for comparing tumor incidence rates. J. Royal Statist. Soc., Ser - C, 54, 51-61.
Peddada, S. D., Dunson, D. B. and Tan, X. (2005). Estimation of order-restricted means from correlated data. Biometrika, 92, 703-715. Supplementary Material pdf(http://dir.niehs.nih.gov/dirbb/peddada/Supplementary.materials.pdf)
Peddada S. D., Harris S., Zajd J. and Harvey E. (2005). ORIOGEN: Order Restricted Inference for Ordered Gene Expression data. Bioinformatics, 21, 3933-3934. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16109745)
Peddada S. D., and Kissling G. (2005). A Survival-Adjusted Quantal-Response Test for Analysis of Tumor Incidence Rates in Animal Carcinogenicity Studies. Environmental Health Perspectives, 114, 537-541. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16581542)
Peddada, S. D., Haseman J., Tan X. and Travlos G. (2006). Tests for simple tree order restriction with application to dose-response studies. J. Royal Statist. Soc., Ser - C, 55, 493-506.
Peddada, S. D., Dinse, G. and Kissling, G. (2006). Incorporating Historical Control Data When Comparing Tumor Incidence Rates. J. Amer. Stat. Assoc, in press.
Simmons, S., and Peddada, S,D. (2007). Order-Restricted Inference for Ordered Gene Expression (ORIOGEN) data under heteroscedastic variances. Bioinformation, 10 (414-419). [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=17597931)
Guo, W., and Peddada, S.D. (2008). Adaptive choice of the number of bootstrap samples in large scale multiple testing. Statistical Applications in Genetics and Molecular Biology, 7: Article 13. Epub 2008 Mar 24. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=18384266)
Statistical Consulting
Gottschling, B. C., Maronpot, R. R., Hailey, J. R., Peddada, S. D., Moomaw, C. R., Klaunig, J. E. and Nyska, A. (2001). Role of Oxidative Stress in Indium Phosphide-induced Lung Carcinogenesis in Rats. Toxicological Sciences, 64, 28-40. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11606799)
Kanno, J., Onyon, L., Peddada, S. D., Ashby, J., Jacob, E., and Owens, W., (2002). The OECD program to validate the rat uterotrophic bioassay. Phase 2: dose-response studies. Environmental Health Perspectives, 111, 1530-1549. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12948896)
Kanno, J., Onyon, L., Peddada, S. D., Ashby, J., Jacob, E., and Owens, W., (2002). The OECD program to validate the rat uterotrophic bioassay: Phase Two - Coded Single Dose Studies. Environmental Health Perspectives, 111, 1550-1558. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12948897)
Nyska, A., Moomaw, C., Foley, J., Maronpot, R., Malarkey, D., Cummings, C., Peddada, S. D., Travlos, G., and Chan, P. (2002). The Hepatic Endothelial Carcinogen Riddelliine Induces Endothelial Apoptosis, Mitosis, S phase, p53 and Hepatocytic Vascular Endothelial Growth Factor Expression After Short-term Exposure. Toxicology and Applied Pharmacology, 184, 153-164. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12460743)
Ezov, N., Levin-Harus, T., Mittelman, M., Redlich, M., Shabat, S., Ward, S., Peddada, S. D., Nyska, M., Yedgar, S. and Nyska, A. (2002). Chemically induced rat model of hemolysis with disseminated thrombosis. Cardiovascular Toxicology, 2, 181-194. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12665664)
Chan, P, Mahler, J., Peddada, S. D., Lomnitski, L., and Nyska, A. (2003). Forestomach tumor induction by 2,4-hexadienal in F344/N rats and B6C3F1 mice. Archives of Toxicology, 77, 511-520. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12879212)
Jarosinska, D., Peddada, S. D. and Rogan, W. (2004). Assessment of lead exposure and associated risk factors in urban children in Silesia, Poland. Environmental Research, 95, 133-142. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15147918)
Shabat, S., Nyska, A., Long, P., Goelman, G., Abramovitch, R., Ezov, N., Levin-Harus, T., Peddada, S. D., Redlich, M., Yedgar, S., Nyska, M. (2004). Osteonecrosis in a chemically induced rat model of human hemolytic disorders associated with thrombosis - A new model for avascular necrosis of bone. Calcified Tissue International, 74, 220-228. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=14517720)
Bishop, J., Tani, Y., Witt, K., Johnson, J., Peddada, S. D., Dunnick, J. and Nyska, A. (2004). Mitochondrial damage revealed by morphometric and semiquantitative analysis of mouse pup cardiomyocytes following in utero and postnatal exposure to Zidovudine and Larnivudine. Toxicological Sciences, 81, 512-517. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15229369)
Deroo, B., Hewitt, S., Peddada, S. D. and Korach, K. (2004). Estradiol regulates the thiorexdoxin antioxidant system in the mouse uterus. Endocrinology, 145, 5485-92. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15345672)
Gray, T., Nettesheim, P., Loftin, C., Koo, J., Bonner, J., Peddada, S. D., and Langenbach, R. (2004). Interleukin-1beta-induced mucin production in human airway epithelium is mediated by cyclooxygenase-2, prostaglandin E2 receptors, and cyclic AMP-protein kinase A signaling. Molecular Pharmacology, 66, 337-346. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15266025)
Tani, Y., Sills, R., Foster, P., Chan, P., Peddada, S. D., and Nyska, A. (2005). Epididymal sperm granuloma induced by chronic administration of 2-methylmidazole in B6C3F1 mice. Toxicologic Pathology, 33, 313-319. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15814360)
Yoshizawa, K., Marsh, T., Foley, J., Cai, B., Peddada, S.D., Walker, N. and Nyska, A. (2005). Mechanisms of exocrine pancreatic toxicity induced by oral treatment with 2,3,7,8-Tetrachlorodibenzo-p-Dioxin in female Harlan Sprague-Dawley rats. Toxicological Sciences, 85, 594-606. [Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15716480)