Sat, 05 Jul 2008 03:46:13 BST CiteULike: jyuh Tyson http://www.citeulike.org/user/jyuh/author/Tyson CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/jyuh/article/2784509 <i>Methods (San Diego, Calif.), Vol. 41, No. 2. (February 2007), pp. 238-247.</i><br /><br />Although not a traditional experimental "method," mathematical modeling can provide a powerful approach for investigating complex cell signaling networks, such as those that regulate the eukaryotic cell division cycle. We describe here one modeling approach based on expressing the rates of biochemical reactions in terms of nonlinear ordinary differential equations. We discuss the steps and challenges in assigning numerical values to model parameters and the importance of experimental testing of a mathematical model. We illustrate this approach throughout with the simple and well-characterized example of mitotic cell cycles in frog egg extracts. To facilitate new modeling efforts, we describe several publicly available modeling environments, each with a collection of integrated programs for mathematical modeling. This review is intended to justify the place of mathematical modeling as a standard method for studying molecular regulatory networks and to guide the non-expert to initiate modeling projects in order to gain a systems-level perspective for complex control systems. Mathematical modeling as a tool for investigating cell cycle control networks. JC Sible JJ Tyson doi:10.1016/j.ymeth.2006.08.003 Methods (San Diego, Calif.), Vol. 41, No. 2. (February 2007), pp. 238-247. 2008-05-11T14:42:42-00:00 2007 Methods (San Diego, Calif.) 1046-2023 41 2 238 247 no-tag http://www.citeulike.org/user/jyuh/article/2393038 <i>The Lancet, Vol. 371, No. 9612., pp. 569-578.</i><br /><br />SummaryBackground Excess bodyweight, expressed as increased body-mass index (BMI), is associated with the risk of some common adult cancers. We did a systematic review and meta-analysis to assess the strength of associations between BMI and different sites of cancer and to investigate differences in these associations between sex and ethnic groups.Methods We did electronic searches on Medline and Embase (1966 to November 2007), and searched reports to identify prospective studies of incident cases of 20 cancer types. We did random-effects meta-analyses and meta-regressions of study-specific incremental estimates to determine the risk of cancer associated with a 5 kg/m2 increase in BMI.Findings We analysed 221 datasets (141 articles), including 282[punctuation space]137 incident cases. In men, a 5 kg/m2 increase in BMI was strongly associated with oesophageal adenocarcinoma (RR 1[middle dot]52, p<0[middle dot]0001) and with thyroid (1[middle dot]33, p=0[middle dot]02), colon (1[middle dot]24, p<0[middle dot]0001), and renal (1[middle dot]24, p <0[middle dot]0001) cancers. In women, we recorded strong associations between a 5 kg/m2 increase in BMI and endometrial (1[middle dot]59, p<0[middle dot]0001), gallbladder (1[middle dot]59, p=0.04), oesophageal adenocarcinoma (1[middle dot]51, p<0[middle dot]0001), and renal (1[middle dot]34, p<0[middle dot]0001) cancers. We noted weaker positive associations (RR <1[middle dot]20) between increased BMI and rectal cancer and malignant melanoma in men; postmenopausal breast, pancreatic, thyroid, and colon cancers in women; and leukaemia, multiple myeloma, and non-Hodgkin lymphoma in both sexes. Associations were stronger in men than in women for colon (p<0[middle dot]0001) cancer. Associations were generally similar in studies from North America, Europe and Australia, and the Asia-Pacific region, but we recorded stronger associations in Asia-Pacific populations between increased BMI and premenopausal (p=0[middle dot]009) and postmenopausal (p=0[middle dot]06) breast cancers.Interpretation Increased BMI is associated with increased risk of common and less common malignancies. For some cancer types, associations differ between sexes and populations of different ethnic origins. These epidemiological observations should inform the exploration of biological mechanisms that link obesity with cancer. Body-mass index and incidence of cancer: a systematic review and meta-analysis of prospective observational studies Andrew Renehan Margaret Tyson Matthias Egger Richard Heller Marcel Zwahlen doi:10.1016/S0140-6736(08)60269-X The Lancet, Vol. 371, No. 9612., pp. 569-578. 2008-02-18T09:03:16-00:00 The Lancet 371 9612 569 578 no-tag