John G. Bannigan

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The heavy metal cadmium (Cd) is a pollutant associated with several modern industrial processes. Cd is absorbed in significant quantities from cigarette smoke, and is known to have numerous undesirable effects on health in both experimental animals and humans, targeting the kidneys, liver and vascular systems in particular. However, a wide spectrum of(More)
The effects of 500 and 300 mg/kg bromodeoxyuridine (BUdR) on the process of fusion of the neural folds were tested after injection into pregnant mice on day 8 of gestation (192 hours postcoitum). Various doses of the natural nucleoside, thymidine (TdR), were also tested. Both doses of BUdR retarded growth to the same extent, but only the larger dose caused(More)
BACKGROUND Cadmium (Cd) is an established experimental teratogen whose effects can be reversed by pretreatment with zinc. Mesodermal development is a frequently reported target for Cd teratogenicity. The aim of this study was to examine the mechanisms of Cd induced body wall defects in chick embryos. METHODS Chick embryos in shell-less culture were(More)
Cadmium (Cd) is teratogenic in chick embryos following treatment in ovo or in shell-less culture. We investigated the ability of other divalent cations (Mn, Ni, Se, Mg and Ca) to influence the effects of Cd. As the proposed mechanism of protection of these ions is prevention of Cd influx by blocking or competing for Ca channels, we also assessed verapamil,(More)
It is well known that 5-bromodeoxyuridine (BUdR) when injected into pregnant animals may cause exencephaly, cleft palate, and limb abnormalities. Similarly, it is well established that the drug when added to a culture medium may prevent differentiation of embryonic cell systems without affecting cell division or cell viability. The goal of our experiments(More)
Cadmium (Cd) is a powerful inducer of oxidative stress. It also causes ventral body wall defects in chick embryos treated at Hamburger-Hamilton stages 16-17. By measuring malondialdehyde levels (TBARS method) and cotreating with antioxidants (tempol, ascorbate, and N-acetylcysteine), we sought to determine if oxidative stress were directly related to(More)
BACKGROUND/PURPOSE The Adriamycin rat model (ARM) is a reliable model of the VACTERL association. The notochord is structurally abnormal in the region of the foregut, midgut, and hindgut in the ARM. The authors hypothesised that notochord anomalies allow ectopic expression of molecular signals in the developing embryo and thus lead to VACTERL malformations.(More)
BACKGROUND/PURPOSE The Adriamycin rat model is an established model for vertebral, anal, cardiac, tracheal, esophageal, renal, and limb (VACTERL) anomalies and gastrointestinal atresias. Mice are the foremost mammal studied by developmental biologists, providing greater availability of molecular probes, antibodies, and transferable knowledge with transgenic(More)
Intrinsic innervation of the developing chick cloaca is provided by the enteric nervous system, a network of neurons and glia that lies within its walls. The enteric nervous system originates from neural crest cells that migrate from the vagal and sacral regions of the neural tube during the early stages of development. Abnormal cloacal development can(More)
Congenital malformations of the foregut are common in humans. The respiratory and digestive tubes are both derived by division of the foregut primordium. Sonic hedgehog (Shh) and Fork head box F1 (Foxf1) genes encode regulatory molecules that play a pivotal role in gut and lung morphogenesis and are therefore important candidate genes to be examined in(More)