Genetic analysis of multifocal superficial urothelial cancers by array-based comparative genomic hybridisation

The purpose of this study was to investigate the accumulation of genetic alterations during metachronous and/or synchronous development of multifocal low-grade superficial urothelial tumours in the same patient, by using array-based comparative genomic hybridisation (array-CGH) and FGFR mutation analysis. We analysed 24 tumours (pTa-1 G1-2) from five patients. We had previously identified a clonal relationship among the tumours of each patient by microsatellite analysis. This time, unsupervised hierarchical cluster analysis revealed that the tumours from each patient were clustered together independently of the tumours from the other patients. All of the tumours from a single patient showed a set of 2–7 identical regional or whole-arm chromosomal changes. In addition, several individual alterations were also found. Cladistic diagrams revealed that the accumulation of genetic alterations could not be explained by a linear model, and the existence of a hypothetical precursor cell was assumed in four patients. In some cases, FGFR mutation seemed to occur later during multifocal tumour development. Taken together, these findings suggest that low-grade superficial urothelial tumours accumulate minor genetic alterations during multifocal development, although these tumours are genetically stable

Time-resolved circularly polarized luminescence of Eu3+-based systems

Chiral Eu3+-based systems are frequently studied via circularly polarized luminescence spectroscopy. The emission lifetimes of each circular polarization, however, are virtually always ignored, because in a homogeneous sample of emitters, there should be no difference between the two. However, we show that in less robust Eu3+ complex structures, as in the chiral complex Eu (facam)3, a difference in the lifetimes of the two circularly polarized emission components arises due to heterogeneity of the complexes. In this case, each species within the sample could have different degrees of circularly polarized luminescence and decay rates at certain emission lines. The superposition of the emission components of the various chiral species leads to an overall difference in decay rate between the two circular polarizations. Such a difference is also shown for Eu3+-doped chiral TbPO4·D2O nanocrystals. We believe that this kind of measurement could be a unique tool for determining the homogeneity of a lanthanide-based chiral system, where other methods might fail in this task

Vitamin D receptor polymorphisms as markers in prostate cancer

Polymorphisms in the vitamin D receptor (VDR) gene have been analyzed in several studies for an association with prostate cancer (PCA) and odds ratios (OR) ? 3 have been observed in study populations from North America. We studied three polymorphisms in the VDR gene (poly-A microsatellite, TaqI and FokI RFLPs) in 105 controls and 132 sporadic PCA cases from France and in a collection of families from Germany and France. The polymorphisms near the 3' end of the gene were in linkage disequilibrium with an almost complete coincidence of the short poly-A alleles and t (presence of the restriction site) of the TaqI polymorphism, (contingency tables, P 0.7). While some association studies differ between Europe and North America, our present findings with the VDR gene agree with those from North America, indicating a weak but general role of the VDR in PCA susceptibility

Linear Systems Description

Introduction The systems approach is a widely used practice in modeling artificial as well as natural phenomena. Each process or sub-process is viewed as an input-output system, as described graphically in Fig.1. This approach is used extensively in engineering, for example in modeling electronic and mechanical systems and in chemical process description. In this chapter we describe this approach and its application to biological systems in general and the nervous system in particular. The systems approach can be used as a modeling tool to comprehend the function of the system and to produce a hypothetical model which can be tested in experiments. It is useful in describing and characterising experimental results, at times by relating the anatomical and physiological properties to the measured variables (see for example the muscle spindle transfer function, Houk 1963). Mathematical modeling of part of the neurological system can be used to study that and other parts by simula