The microvascular network of the pituitary gland: a model for the application of fractal geometry to the analysis of angioarchitecture and angiogenesis of brain tumors.

In geometrical terms, tumor vascularity is an exemplary anatomical system that irregularly fills a three-dimensional Euclidean space. This physical characteristic, together with the highly variable vessel shapes and surfaces, leads to considerable spatial and temporal heterogeneity in the delivery of oxygen, nutrients and drugs, and the removal of metabolites. Although these biological features have now been well established, quantitative analyses of neovascularity in two-dimensional histological sections still fail to view tumor architecture in non-Euclidean terms, and this leads to errors in visually interpreting the same tumor, and discordant results from different laboratories. A review of the literature concerning the application of microvessel density (MVD) estimates, an Euclidean-based approach used to quantify vascularity in normal and neoplastic pituitary tissues, revealed some disagreements in the results and led us to discuss the limitations of the Euclidean quantification of vascularity. Consequently, we introduced fractal geometry as a better means of quantifying the microvasculature of normal pituitary glands and pituitary adenomas, and found that the use of the surface fractal dimension is more appropriate than MVD for analysing the vascular network of both. We propose extending the application of this model to the analysis of the angiogenesis and angioarchitecture of brain tumors.

Simultaneous staining of cytoplasmic iron and collagen matrix in human liver biopsy specimens.

One of the major liver fibrogenic activators is the cellular iron overload that can severely damage parenchymal and non-parenchymal cells. The aim of this study was to investigate a histochemical staining technique that allows the simultaneous detection of the irregular deposition of matrix collagen and both the amount and distribution of iron in liver cells on the same histological section. The method was evaluated using 3-microm histological sections obtained from ten standard liver biopsy specimens taken from patients with hepatitis C virus-related diseases and simultaneous liver cell iron overload. The results indicate that the double-staining technique is simple, sensitive and rapid, and can be routinely applied to liver biopsy specimens for diagnostic purposes. Furthermore, it may also facilitate the study of the complex relationship between hepatic fibrosis and iron overload during common genetic or secondary liver metabolic disorders.

Fractal geometry: a useful tool for quantifying irregular lesions in human liver biopsy specimens.

Irregularity and complexity are the main features of every biological system, including human tissues, cells and sub-cellular components. These two properties of the organized biological matter cannot be quantified by means of the classical Euclidean geometry, which is able to measure regular object, practically unknown in Nature. The aims of our paper were a) to underline the importance of the shape of a biological structure, b) to investigate the fractal geometry for quantifying the liver histo-pathological structures, and c) to explain the significance of several terms used in the fractal analysis of complex biological systems.

Molecular disorders in transitional vs. peripheral zone prostate adenocarcinoma.

Loss of heterozygosity (LOH) and microsatellite instability (MSI) have been shown to be mechanisms for tumor-suppressor gene inactivation in human oncogenesis. In our study, we examined LOH and MSI using 16 polymorphic markers of DNA for chromosomes 1, 3, 7, 8, 10 and 11. Microdissected tumor samples were isolated from 32 patients, representing 11 foci of incidentally discovered prostate cancer of the transitional zone (TZ), 12 prostate cancer of the peripheral zone (PZ) and 10 of high-grade PIN. We found loss of heterozygosity in the TZ group in 91% of informative cases (10/11) with al least 1 marker compared to 58% of cases (7/12) in PZ group and 70% of cases (7/10) in the HGPIN group. Chromosome 7 showed the highest rate of allelic loss in all 3 categories, with loss of 43% of loci in PIN, 37% in TZ tumors and 31% in PZ tumors. At chromosome 11, LOH was detected in 26% of loci in the TZ group, in 7% of loci in the PZ group and in 13% of loci in the PIN group. On chromosome 8, the PZ and HGPIN group showed allelic loss in 22% and 21% of loci, respectively, compared to 10% detected in the TZ group. The TZ group showed a significant higher rate of allelic instability compared to that observed in tumor samples from the peripheral zone: 73% of cases (8/11) showed genetic alterations (RER+ phenotype) in at least 4 loci analyzed compared to 8% and 10% in the PZ and HGPIN groups, respectively (p = 0.0006). These data suggest that transitional zone carcinoma and peripheral zone carcinoma display distinct and specific genetic alterations in different chromosomes. This diversity may help explain biologic and clinical differences between carcinomas arising in these distinct zones of the prostate. Also our results strongly suggest that the RER+ mutator phenotype could be linked to early development of transitional zone prostate carcinoma.