Statistical modelling of the geometry of planar sections of prostatic capillaries on the basis of stationary Strauss hard-core processes

In a recent study, the capillarization of normal prostatic tissue and prostatic carcinoma tissue was characterized by means of explorative methods of spatial statistics. In the present paper, an attempt was made to go beyond the explorative approach and to characterize the observed point patterns of the capillary profiles on sections by means of a parametric model. For this purpose, the flexible class of Gibbs processes was considered. Specifically, stationary Strauss hard-core processes were fitted to the observed point patterns. The goodness of fit achieved by the model was checked by simulations with the Markov chain Monte Carlo method using the Metropolis–Hastings algorithm. Model fitting and simulations were performed with the help of the spatstat package under R. The observed point patterns were in some cases compatible with realizations of stationary Strauss hard-core processes for all ranges of spatial interaction. However, deviations from the model were found for one or more domains of ranges in other cases. In the tumour tissue, a highly significant decrease of the interaction parameter of the Strauss hard-core process could be found as compared to the normal prostatic tissue. This finding is discussed in terms of a loss of the normal lobular architecture of the glands in the tumour tissue.     

Correlative light and electron microscopy for the analysis of cell division

Correlative light and electron microscopy (CLEM) has recently gained increasing attention, because it enables the acquisition of dynamic as well as ultrastructural information about subcellular processes. It is the power of combining the two imaging modalities that gives additional information as compared to using the imaging techniques separately. Here, we briefly summarize two CLEM approaches for the analysis of cells in mitosis and cytokinesis.     

PERCEPTION OF TEXTURE AND FLAVOR IN SOUPS BY ELDERLY AND YOUNG SUBJECTS

The perception of texture and flavor and their interaction effects in white cream soups were studied in 12 young subjects (18–29 years) and 15 elderly subjects (60–84 years). Eight soup samples (2 × 2 × 2 factorial design) were prepared with or without potato starch, with or without mushroom flavor and with water or with milk. The elderly were less sensitive to changes in the flavor profile of the soups than the young, and their perception of creaminess was reduced. Solvent by flavor interaction effects were independent of age, whereas texture by flavor interaction effects were age specific. Besides the intensities of flavor and texture attributes, pleasantness was also assessed. No indication was found that the contribution of texture and flavor to food appreciation was different for the young and for the elderly in the current study. This study supports the assumption that age‐related differences in product perception exist.     

DNA Sequencing and Analysis of 130 kb from Yeast Chromosome XV

We have determined the nucleotide sequence of 129 524 bases of yeast (Saccharomyces cerevisiae) chromosome XV. Sequence analysis revealed the presence of 59 non-overlapping open reading frames (ORFs) of length >300 bp, three tRNA genes, four delta elements and one Ty-element. Among the 21 previously known yeast genes (36% of all ORFs in this fragment) were nucleoporin (NUP1), ras protein (RAS1), RNA polymerase III (RPC1) and elongation factor 2 (EF2). Further, 31 ORFs (53% of the total) were found to be homologous to known protein or DNA sequences, or sequence patterns. For seven ORFs (11% of the total) no homology was found. Among the most interesting protein identifications in this DNA fragment are an inositol polyphosphatase, the second gene of this type found in yeast (homologous to the human OCRL gene involved in Lowe's syndrome), a new ADP ribosylation factor of the arf6 subfamily, the first protein containing three C2 domains, and an ORF similar to a Bacillus subtilis cell-cycle related protein. For each ORF detailed sequence analysis was carried out, with a full consideration of its biological function and pointing out key regions of interest for further functional analysis. The sequence has been submitted to the EMBL data library under Accession Number X94335.© 1997 John Wiley & Sons, Ltd.