Intratumor heterogeneity of biomarker expression in breast carcinomas

Small biopsy samples are used increasingly to assess the biomarker expression for prognostic information and for monitoring therapeutic responses prior to and during neoadjuvant therapy. The issue of intratumor heterogeneity of expression of biomarkers, however, has raised questions about the validity of the assessment of biomarker expression based on limited tissue samples. We examined immunohistochemically the expression of HER-2neu (p185^erbB-2), epidermal growth factor receptor (EGFR), Bcl-2, p53, and proliferating cell nuclear antigen (PCNA) in 30 breast carcinomas using archived, paraffin embedded tissue and determined the extent of intratumor heterogeneity. Each section was divided into four randomly oriented discrete regions, each containing a portion of the infiltrating carcinoma. For each tumor, the entire lesion and four regions were analyzed for the expression of these markers. Scores of both membrane and cytoplasmic staining of HER-2neu and EGFR, scores of cytoplasmic staining of Bcl-2, and scores of nuclear staining of both p53 and PCNA were recorded. The intensity of staining and the proportion of immunostained cells were determined. A semiquantitative immunoscore was calculated by determining the sum of the products of the intensity and corresponding proportion of stained tumor cells. We analyzed both invasive (IDC) and in situ (DCIS) carcinomas. The Wilcoxon signed-rank test was used for paired comparisons between overall and regional immunoscores and between overall and regional percentages of stained cells. Spearman's correlation coefficients were used to assess the level of agreement of overall biomarker expression with each of the regions. Generalized linear models were used to assess overall and pair-wise differences in the absolute values of percent changes between overall and regional expression of biomarkers. For IDCs, there were no statistically significant differences in the expression of the biomarkers in terms of either the percentage of cells staining or the immunoscores when comparing the entire tumor with each region except for the lower EGFR expression of arbitrarily selected region 1 and lower p53 expression of region 1 compared to that of the entire tumor section. For DCIS, there were no statistically significant differences in the expression of the biomarkers between the entire tumor and each region except in PCNA of region 2 compared to that of entire tumor section. Positive correlation of immunoscores was observed between the entire tumor and each region as well as across all four regions for IDC. Similar observations were noted with DCIS except for HER-2neu and PCNA. No statistically significant differences were observed in the absolute values of percent changes of biomarker expression between overall and the four regions for both DCIS and IDC. Therefore, no significant intratumor heterogeneity in the expression of HER-2neu, Bcl-2, and PCNA was observed in IDC. Minor regional variations were observed for EGFR and p53 in IDC. Similarly, no significant regional variation in the expression of markers was observed in DCIS except for PCNA.     

Anatomical investigations of resprouting in Cardopatum corymbosum L. (Asteraceae): A hemicryptophyta living on erosion-prone slopes in a Mediterranean climate

Abstract

Cardopatum corymbosum is a perennial hemicryptophyta species living on erosion-prone steep slopes where it forms very small, scattered communities that resist soil erosion. The aim of this study was to understand better the life cycle of this species before suggesting its use for eco-engineering purposes to stop soil erosion. We examined anatomical preparations with a light microscope, and plant anatomy was reconstructed by examining sequential cross sections of the stem cut from the shoot apex to the root collar. A single sprout above the root collar produces a rosette of leaves at the beginning of spring and a floral axis at the end of summer. The leaves and the floral axis die at the end of summer, whereas the basal portion of the new stem remains alive and forms, together with the root system, the perennial portion of this plant. This stem zone is named “transition zone” and presents leaf traces converging in the centre where they give rise to a vascular cylinder with a cambium ring dividing a secondary xylem from a secondary phloem. New buds form in the cortex of the transition zone that are quiescent and are not visible externally until the following spring when they resume growth and generate a new sprout. These buds should be considered adventitious because: (1) they form independently of leaves; and (2) their annual production could represent the plant's response to ensure its survival after the loss of the above-ground portion of the stem. Given the efficient resprouting strategy coupled with a perennial root system, C. corymbosum is a good candidate for bio-engineering applications against the soil erosion typical of steep slopes in Mediterranean climates. This species could be considered for intensive re-vegetation in order to produce a protective soil covering.     

Improving vigour assessment of pine (Pinus nigra Arnold) seedlings before their use in reforestation

ABSTRACT

We investigated whether changes in the root system of pine seedlings induced by stress (lifting of bare-root seedlings from the nursery bed irrespective of dormancy; prolonged storage of bare-root seedlings in a cold room) could provide a measure of plant vigour. Physiological parameters, such as growth potential and root electrolyte leakage, and morphological parameters, such as root length and number of root tips, were calculated. Computerised image analysis was used to measure root growth, overall and based on root-diameter class (0–0.5 mm, 0.5–1.0 mm and 1.0–1.5 mm). The efficiency of vigour assessment was evaluated by correlating the data for each parameter with percentage seedling survival. Root growth potential was more efficient than root electrolyte leakage, but both parameters were affected by seedling age. Total root length was a more efficient indicator of plant vigour than root tip number, particularly when referred to roots of the same diameter class. A comparative analysis of physiological and morphological parameters referred to the root systems improves their relative effciency.     

Modification of chromatin organisation at low water potential in cultured cells of Solanum tuberosum: Possible involvement of dehydrins

ABSTRACT

To understand the mechanisms which enable the nucleus to function under low water potential, the morphology and biochemistry of potato cell nuclei were studied. Conformational modifications were observed in the chromatin of nuclei of cells growing under low water potential. These modifications include a higher number of heterochromatic centres, enlargement of the nuclear diameter, and a different accessibility of DNA to the action of restriction enzymes. Biochemical analyses showed that these chromatin modifications may coincide with quantitative and qualitative variations of several nuclear proteins, some of which may belong to the dehydrin family. We especially focussed our attention on a 45-kDa protein that is heat-stable and is recognised by an antibody raised against the conserved domain of dehydrins. The survival of potato cells in an environment where water availability is low may depend on several simultaneous events regarding the nucleus. The accumulation in the nucleus of specific proteins such as dehydrins could be required to stabilise the chromatin by means of their molecule-salvation action. Further studies are in progress to check whether or not variations in chromatin organisation may be one of the numerous traits that a cell must acquire to become water-stress resistant.     

Biochemical investigations of the nuclear proteins during the transition of root meristems from quiescent to proliferating state in Pisum sativum

Abstract

The electrophoretic analysis of nuclear proteins extracted from root meristems at different times of germination puts in evidence the variations of content of specific proteins. Several nuclear proteins are phosphorylated by endogenous protein kinase and often the maximum rate of phosphorylation it has been observed in proteins present in the nucleus at low concentrations. Moreover also the phosphorylation rate of specific proteins changes at different times of germination. It is interesting the fact that both variations of concentration and phosphorylation in nuclear proteins occurr at the time when root meristems leave the quiescence to enter a proliferating state. We suggest that these variations play a role in this physiological event.     

Manganese Tetraphenylporphyrins Catalyzed Selective Oxidation of Purine Derivatives

Abstract

The oxidation of purine derivatives using porphyrins as catalysts and dimethyldioxirane (DMDO) as oxygen atom donor is reported. The regioselectivity of the oxidation was found to be dependent on the presence of a free OH moiety on the N(9)-side chain of the substrate and on the structure of the catalyst.     

Effect of Polymer Crystallinity in P3HT:PCBM Solar Cells on Band Gap Trap States and Apparent Recombination Order

The non‐geminate recombination of charge carriers in polymer‐fullerene solar cells has been modeled in the last few years with a trap‐assisted recombination model, which states that the apparent recombination order depends on the concentration of trapped charges tailing into the band gap. Higher concentrations of trapped charges lead to higher apparent recombination orders. In this work, the mass fraction f of highly crystalline nanofibrillar P3HT to the total P3HT content in P3HT:PCBM solar cells is consistently varied, controlling the temperature of a nanofibers‐P3HT casting dispersion. A systematic study of the apparent recombination order, measured with a transient photovoltage technique, as a function of f is presented. A correlation is shown between the apparent recombination order, the P3HT crystallinity, and the trap concentration in the band gap measured with an admittance spectroscopy technique.