Radiodiagnostic Imaging in Pregnancy and the Risk of Childhood Malignancy: Raising the Bar

Eduardo Franco and Guy-Anne Turgeon discuss new findings from Joel Ray and colleagues on the cancer risk following prenatal exposure to radiodiagnostic imaging, and where new research needs to be focused

A microbiological assay for host-specific fungal polyketide toxins

Genetic analysis of biosynthetic pathways for fungal secondary metabolites depends on availability of efficient and dependable assays for the end products. Some fungal plant pathogens produce secondary metabolites called host-specific toxins. Until recently, all bioassays for these toxins required use of whole plants or plant parts (Yoder 1981 In: Toxins in Plant Disease, Durbin ed., pp. 45-78). Since host-specific toxins, by definition, affect only plants that are susceptible to the toxin-producing fungus, other plants, animals and microorganisms are not sensitive and therefore cannot be used in bioassays

Étude de l'angiogénèse et développement d'un modèle animal pour l'étude du sarcome de Kaposi

La progression du virus du SIDA chez l'humain a atteint une telle proportion qu'aucune classe de la société n'est à l'abri. L'avènement du SIDA a causé une incidence plus élevée de certaines pathologies, comme le sarcome de Kaposi (SK). Il s’agit d’un cancer des cellules endothéliales, pour lequel aucun modèle expérimental n’existait. Nous avons développé, dans le cadre de nos recherches, un modèle de souris qui mime en partie les conditions rencontrées chez les patients sidéens souffrant du SK. Puisqu'il s'agissait d'une néoplasie des cellules endothéliales, nos recherches ont été dirigées vers des traitements antiangiogéniques. La première partie de l'étude a été effectuée sur l'angiogénèse, et consistait en des traitements apposés à la surface de la membrane chorio-allantoïdienne (CAM). Nous avons utilisé le tétraHydro S ainsi que le 17?-hydroxyprogestérone combiné au MTP déposés en forme de disque à la surface de la CAM. Nous avons obtenu des zones avasculaires confirmant leur activité. La combinaison MTP-tétrahydro S a donné les meilleurs résultats. La seconde partie contient l'objectif principal de cette recherche. Trente semaines d'injections hebdomadaires s.c. de DMH chez des souris C57BI/6 mâles induisent I’apparition d'angiosarcomes dans 80 % des cas. Nous avons augmenté I’immunosuppression de ces souris en utilisant le virus LP-BM5. Les paramètres immunitaires ont été étudiés à l'aide: de stimulation en présence de Con A ou de LPS, de la réponse PFC et d'un dénombrement lymphocytaire du sang et de la rate

Split-Marker Recombination for Efficient Targeted Deletion of Fungal Genes

A commonly used method for fungal gene deletion is introduction of linear DNA consisting of a selectable marker gene flanked on both sides by short stretches of DNA that target a gene of interest (Wirsel et al 1996 Curr. Genet 29:241-249). Gene deletion in Cochliobolus heterostrophus and Gibberella zeae occurs efficiently with this approach. To facilitate deletion construct synthesis, we have applied the split-marker” deletion strategy previously developed for Saccharomyces cerevisiae (Fairhead et al. 1996 Yeast 12:1439-57; Fairhead et al. 1998 Gene 223:33-46). Here, we describe both fusion PCR-based and plasmid-based deletion methods using this strategy with PEG-mediated protoplast transformation (Turgeon et al, 1985 Mol. Gen. Genet. 201:450-453). These methods are predicted to work well with any transformable fungus that undergoes homologous recombination between chromosomal and introduced DNA sequences

Zinc modulates GABAB binding in rat brain

The effects of ZnCl2 on [3H]GABA binding to GABAA and GABAB binding sites were investigated using receptor autoradiography. At concentrations exceeding 100 [mu]M, zinc non-competitively inhibited GABAB binding in a dose dependent fashion. GABAA binding was not inhibited significantly by zinc eliminating the possibility of a non-specific effect of zinc. Increased calcium concentrations up to 10 MM enhanced total GABAB binding but did not prevent zinc induced inhibition of GABAB binding, indicating a separate site of action for these cations at the GABAB binding site. In some regions, zinc modulates GABAB binding in a biphasic manner as concentrations of 10-100 [mu]M zinc significantly enhanced GABAB binding in the hippocampus and the molecular layer of the cerebellum but not in the thalamus. These results provide further evidence for a neuromodulatory role for zinc in the central nervous system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29723/1/0000057.pd

GABAB binding sites in early adult and aging rat brain

The effect of aging on GABAB binding was investigated in rat brain. Receptor autoradiography was used to investigate both GABAB and GABAA binding at 2 months, 3 months, 13 months, and 23 months. GABAB binding decreases significantly between 2 months and 23 months of age, as does GABAA binding, with was investigated in rat brain. Receptor autoradiography was used to investigate both GABAB and GABAA binding at 2 months, 3 months, 13 months, and 23 months. GABAB binding decreases significantly between 2 months and 23 months of age, as does GABAA binding, with greatest decrease between 2 and 3 months. The decrease in GABAB binding appears to be due to a decrease in binding site affinity rather than a decrease in receptor density. The noncompetitive GABAB antagonist zinc, the competitive GABAB antagonist CGP 35348, and the guanyl nucleotide analogue GTP-[gamma]-S all inhibit GABAB binding identically in 2 month and 23 month brain. These data indicate subtle age-related changes in the GABAB binding in early adult life but little change with senescence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31228/1/0000130.pd