Thyroid disrupting effects of low-dose dibenzothiophene and cadmium in single or concurrent exposure: New evidence from a translational zebrafish model.

Thyroid hormones (THs) are major regulators of biological processes essential for correct development and energy homeostasis. Although thyroid disruptors can deeply affect human health, the impact of exogenous chemicals and in particular mixture of chemicals on different aspects of thyroid development and metabolism is not yet fully understood. In this study we have used the highly versatile zebrafish model to assess the thyroid axis disrupting effects of cadmium (Cd) and dibenzothiophene (DBT), two environmental endocrine disruptors found to be significantly correlated in epidemiological co-exposure studies. Zebrafish embryos (5hpf) were exposed to low concentrations of Cd (from 0.05 to 2 µM) and DBT (from 0.05 to 1 µM) and to mixtures of them. A multilevel assessment of the pollutant effects has been obtained by combining in vivo morphological analyses allowed by the use of transgenic fluorescent lines with liquid chromatography mass spectrometry determination of TH levels and quantification of the expression levels of key genes involved in the Hypothalamic-Pituitary-Thyroid Axis (HPTA) and TH metabolism. Our results underscore for the first time an important synergistic toxic effect of these pollutants on embryonic development and thyroid morphology highlighting differences in the mechanisms through which they can adversely impact on multiple physiological processes of the HPTA and TH disposal influencing also heart geometry and function.

Expression and characterization of the periplasmic cobalamin-binding protein of Photobacterium damselae subsp. piscicida.

Abstract Cobalamin (vitamin B(12)) is an essential cofactor in a variety of enzymatic reactions and most prokaryotes contain transport systems to import vitamin B(12). A gene coding for a periplasmic cobalamin-binding protein of Photobacterium damselae subsp. piscicida was identified by in silico analysis of sequences from a genomic library. The open reading frame was composed of 834 bp encoding a protein of 277 amino acids. The protein showed 61% identity with the vitamin B(12)-binding protein precursor of P. profundum, 53% identity with the corresponding protein of Vibrio parahaemolyticus and 43% identity with the periplasmic binding protein BtuF of Escherichia coli. The expression of the native protein was investigated in P. damselae subsp. piscicida, but BtuF was weakly expressed under normal conditions. To characterize the BtuF of P. damselae subsp. piscicida, the recombinant protein was expressed with a C-terminal His(6)-tag and purified; the molecular weight was estimated to be approximately 30 kDa. The protein does not contain any free thiol group, consistent with the view that the two cysteine residues are involved in a disulphide bond. The purified BtuF binds cyanocobalamin with an affinity constant of 6 +/- 2 microm.

Cord blood banking for stem cell transplant.

Umbilical cord blood has been recently used as a source of hematopoietic progenitor cells for transplantation of pediatric patients. This study was performed to evaluate the feasibility of a cord blood bank for unrelated transplant. When the umbilical cord was clamped within 20 seconds after delivery, it was possible to collect 86 +/- 25 ml of cord recipients with more than 2000 CFU-GM/kg; 53% of cord blood samples were found to contain enough CFU-GM for engraftment in 50-70 kg adult patients.

Umbilical cord blood banking: evaluation of the collection procedure and of CFU-GM content.

Procedures have been optimized for the collection and evaluation of colony-forming cells (CFG-FM) in umbilical cord blood. In a study of 64 samples, early clamping of the cord resulted in increased collection volumes. CFU-GM were not significantly affected by the choice of culture medium.