Analysis of tissue surrounding thyroid nodules by ultrasound digital images

Since US is not easily reproducible, the digital image analysis (IA) has been proposed so that the image evaluation is not subjective. In fact, IA meets the criteria of objectivity, accurateness, and reproducibility by a matrix of pixels whose value is displayed in a gray level. This study aims at evaluating via IA the tissue surrounding a thyroid nodule (backyard tissue, BT) from goitres with benign (b-BT) and malignant (m-BT) lesions. Sixty-nine US images of thyroid nodules surrounded by adequate thyroid tissue was classified as normoechoic and homogeneous were enrolled as study group. Forty-three US images from normal thyroid (NT) glands were included as controls. Digital images of 800 × 652 pixels were acquired at a resolution of eight bits with a 256 gray levels depth. By one-way ANOVA, the 43 NT glands were not statistically different (P = 0.91). Mean gray level of normal glands was significantly higher than b-BT (P = 0.026), and m-BT (P = 0.0001), while no difference was found between b-BT and m-BT (P = 0.321). NT tissue boundary external to the nodule was found at 6.0 ± 0.5 mm in cancers and 4.0 ± 0.5 mm in benignancies (P = 0.001). These data should indicate that the tissue surrounding a thyroid nodule may be damaged even when assessed as normal by US. This is of interest to investigate the extranodular effects of thyroid tumors

Prospecting environmental mycobacteria: combined molecular approaches reveal unprecedented diversity

Background: Environmental mycobacteria (EM) include species commonly found in various terrestrial and aquatic environments, encompassing animal and human pathogens in addition to saprophytes. Approximately 150 EM species can be separated into fast and slow growers based on sequence and copy number differences of their 16S rRNA genes. Cultivation methods are not appropriate for diversity studies; few studies have investigated EM diversity in soil despite their importance as potential reservoirs of pathogens and their hypothesized role in masking or blocking M. bovis BCG vaccine. Methods: We report here the development, optimization and validation of molecular assays targeting the 16S rRNA gene to assess diversity and prevalence of fast and slow growing EM in representative soils from semi tropical and temperate areas. New primer sets were designed also to target uniquely slow growing mycobacteria and used with PCR-DGGE, tag-encoded Titanium amplicon pyrosequencing and quantitative PCR. Results: PCR-DGGE and pyrosequencing provided a consensus of EM diversity; for example, a high abundance of pyrosequencing reads and DGGE bands corresponded to M. moriokaense, M. colombiense and M. riyadhense. As expected pyrosequencing provided more comprehensive information; additional prevalent species included M. chlorophenolicum, M. neglectum, M. gordonae, M. aemonae. Prevalence of the total Mycobacterium genus in the soil samples ranged from 2.3×107 to 2.7×108 gene targets g−1; slow growers prevalence from 2.9×105 to 1.2×107 cells g−1. Conclusions: This combined molecular approach enabled an unprecedented qualitative and quantitative assessment of EM across soil samples. Good concordance was found between methods and the bioinformatics analysis was validated by random resampling. Sequences from most pathogenic groups associated with slow growth were identified in extenso in all soils tested with a specific assay, allowing to unmask them from the Mycobacterium whole genus, in which, as minority members, they would have remained undetected

Regeneration of Pancreatic Non-β Endocrine Cells in Adult Mice following a Single Diabetes-Inducing Dose of Streptozotocin

The non-β endocrine cells in pancreatic islets play an essential counterpart and regulatory role to the insulin-producing β-cells in the regulation of blood-glucose homeostasis. While significant progress has been made towards the understanding of β-cell regeneration in adults, very little is known about the regeneration of the non-β endocrine cells such as glucagon-producing α-cells and somatostatin producing δ-cells. Previous studies have noted the increase of α-cell composition in diabetes patients and in animal models. It is thus our hypothesis that non-β-cells such as α-cells and δ-cells in adults can regenerate, and that the regeneration accelerates in diabetic conditions. To test this hypothesis, we examined islet cell composition in a streptozotocin (STZ)-induced diabetes mouse model in detail. Our data showed the number of α-cells in each islet increased following STZ-mediated β-cell destruction, peaked at Day 6, which was about 3 times that of normal islets. In addition, we found δ-cell numbers doubled by Day 6 following STZ treatment. These data suggest α- and δ-cell regeneration occurred rapidly following a single diabetes-inducing dose of STZ in mice. Using in vivo BrdU labeling techniques, we demonstrated α- and δ-cell regeneration involved cell proliferation. Co-staining of the islets with the proliferating cell marker Ki67 showed α- and δ-cells could replicate, suggesting self-duplication played a role in their regeneration. Furthermore, Pdx1+/Insulin− cells were detected following STZ treatment, indicating the involvement of endocrine progenitor cells in the regeneration of these non-β cells. This is further confirmed by the detection of Pdx1+/glucagon+ cells and Pdx1+/somatostatin+ cells following STZ treatment. Taken together, our study demonstrated adult α- and δ-cells could regenerate, and both self-duplication and regeneration from endocrine precursor cells were involved in their regeneration

Catalogue of scaling laws and similitude questions in geotechnical centrifuge modelling

During The TC2 meeting at St John's (Canada) in July 2002, the firts author, J. Garnier (LCPC), suggested making an inventory of the scaling laws and similitude questions relating to centrifuge modelling. The aim of this catalogue is to present the questions already solved (with the references of the papers where results have been presented) and the unsolved problems (on which research should continue). This catalogue will be regurlarly updated, every four years during the International Conferences on Physical Modelling in Geotechnics. The latest version of the catalogue is available on the TC2 website (www.tc2.civil.uwa.edu.au)