University of Texas Health Science Center at Houston

About: University of Texas Health Science Center at Houston is a education organization based out in Houston, Texas, United States. It is known for research contribution in the topics: Population & Cancer. The organization has 27309 authors who have published 42520 publications receiving 2151596 citations. The organization is also known as: UTHealth & The UT Health Science Center at Houston.

Multiscale modelling and nonlinear simulation of vascular tumour growth.

Abstract: In this article, we present a new multiscale mathematical model for solid tumour growth which couples an improved model of tumour invasion with a model of tumour-induced angiogenesis. We perform nonlinear simulations of the multi-scale model that demonstrate the importance of the coupling between the development and remodeling of the vascular network, the blood flow through the network and the tumour progression. Consistent with clinical observations, the hydrostatic stress generated by tumour cell proliferation shuts down large portions of the vascular network dramatically affecting the flow, the subsequent network remodeling, the delivery of nutrients to the tumour and the subsequent tumour progression. In addition, extracellular matrix degradation by tumour cells is seen to have a dramatic affect on both the development of the vascular network and the growth response of the tumour. In particular, the newly developing vessels tend to encapsulate, rather than penetrate, the tumour and are thus less effective in delivering nutrients.

14-3-3ε is important for neuronal migration by binding to NUDEL: a molecular explanation for Miller–Dieker syndrome

Abstract: Heterozygous deletions of 17p13.3 result in the human neuronal migration disorders isolated lissencephaly sequence (ILS) and the more severe Miller–Dieker syndrome (MDS). Mutations in PAFAH1B1 (the gene encoding LIS1) are responsible for ILS and contribute to MDS, but the genetic causes of the greater severity of MDS are unknown. Here, we show that the gene encoding 14-3-3e (YWHAE), one of a family of ubiquitous phosphoserine/threonine–binding proteins, is always deleted in individuals with MDS. Mice deficient in Ywhae have defects in brain development and neuronal migration, similar to defects observed in mice heterozygous with respect to Pafah1b1. Mice heterozygous with respect to both genes have more severe migration defects than single heterozygotes. 14-3-3e binds to CDK5/p35-phosphorylated NUDEL and this binding maintains NUDEL phosphorylation. Similar to LIS1, deficiency of 14-3-3e results in mislocalization of NUDEL and LIS1, consistent with reduction of cytoplasmic dynein function. These results establish a crucial role for 14-3-3e in neuronal development by sustaining the effects of CDK5 phosphorylation and provide a molecular explanation for the differences in severity of human neuronal migration defects with 17p13.3 deletions.

An evaluation of the molecular clock hypothesis using mammalian DNA sequences.

Abstract: A statistical analysis of extensive DNA sequence data from primates, rodents, and artiodacytls clearly indicates that no global molecular clock exists in mammals. Rates of nucleotide subsitution in rodents are estimated to be four to eight times higher than those in higher primates and two to four times higher than those in artiodactyls. There is strong evidence for lower substitution rates in apes and humans than in monkeys, supporting the hominoid slowdown hypothesis. There is also evidence for lower rates in humans than in apes, suggesting a further rate slowdown in the human lineage after the separation of humans from apes. By contrast, substitution rates are nearly equal in mouse and rat. These results suggest that differences in generation time or, more precisely, in the number of germline DNA replications per year are the primary cause of rate differences in mammals. Further, these differences are more in line with the neutral mutation hypothesis than if the rates are the same for short-and long-living mammals.