Ryan Paulson

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The objective of this investigation was to study the teratogenic effects of dosage levels and time of administration of three anticonvulsant drugs (carbamazepine [CMZ], sodium valproate [NaV], and diphenylhydantoin [DPH]) on craniofacial development in the CD-1 mouse fetus. Pregnant females were intubated on each of days 8-10, 11-13, 14-16, and 8-16 of(More)
The objective of this study was to examine three dimensionally the embryonic and fetal stages of tongue development with scanning electron microscopy. Time-bred CD-1 mice were sacrificed at quarter-day intervals on days 10-13, and at half-day intervals on days 13.5-16.5 of gestation. Fetal tongues were dissected and fixed in s-collidine buffered 4%(More)
A causal association has now been recognized between the use of the anticonvulsant drug sodium valproate during pregnancy and the increased incidence of spina bifida in the human population. The objective of this study was to investigate the teratogenic effects of sodium valproate on the cephalic 1) neuroepithelium, 2) extracellular matrix, and 3) embryonic(More)
Three dosages of Smokeless Tobacco (ST) extract were given to pregnant Sprague-Dawley rats by oral gavage on gestational days (GD) 6-20. The three dosages contained ST extract equivalent to 1.33 mg/kg nicotine (STD-1), 4.0 mg/kg nicotine (STD-2), and 6.0 mg/kg nicotine (STD-3). Dams were intubated three times per day at 8 a.m., 11 a.m., and 2 p.m.,(More)
Two dosages of Smokeless Tobacco (ST) extract were given to gravid Sprague-Dawley rats by oral gavage on gestational days (GD) 6-20. The low dosage contained ST extract equivalent to 1.33 mg/kg nicotine (STD-1), and the high dosage contained ST extract equivalent to 4.0 mg/kg nicotine (STD-2). Dams were dosed three times daily at 8 a.m., 11 a.m., and 2(More)
Valproate sodium has been implicated in the production of spina bifida in humans; this article reports an animal model. Teratogenicity of valproate sodium was studied by oral administration of single doses of 225, 340, and 560 mg/kg to pregnant CD-1 mice on days 7 through 12 of gestation. All fetuses were examined on day 17. Treated fetuses demonstrated(More)
Feeding behaviour changes drastically during metamorphosis as larval suction feeders become adult lingual feeders. In order to understand this transition, the general morphological development of the floor of the buccal cavity in embryonic and larval Rana pipiens was studied, up to the completion of metamorphosis, by scanning electron microscopy. Rana(More)
The objective of this study was to examine the effect of smokeless tobacco (ST) on the development of the CD-1 mouse fetus. ST was administered continuously via Alzet osmotic minipumps during the critical gestational days 7-14 and 6-13. Two ST dosages were administered, 3.2 mg/ml (Dosage I) and 6.4 mg/ml (Dosage II), which yielded plasma nicotine levels(More)
The objective of this study was to examine the effect of an aqueous extract of smokeless tobacco (ST) on the development and bone ossification of the Sprague Dawley rat fetus at known nicotine blood levels. Dams were intubated with the ST extract three times daily on gestational days (GD) 6-18 with one of the following: ST equivalent to either 1.33 mg(More)