Walter L. Davis

Learn More
Developmental craniofacial anomalies related to the neural crest derived ectomesenchymal cell population are associated with fetal alcohol syndrome (FAS). Information regarding any potential relationship between ethanol, free radicals, and the viability, proliferation, etc., of isolated neural crest cells was sought. The hypersensitivity of neural crest(More)
The effects of isotretinoin (IR) and its primary metabolite (in the human), 4-oxo-isotretinoin (4-OIR or OIR), on isolated chick neural crest cells (NCC's) in culture were studied. NCC's were found to be deficient in both superoxide dismutase (SOD) and catalase, two of the enzymes known to function in the "scavenging" (dismutation) of toxic radical oxygen(More)
Light microscopy, transmission electron microscopy, scanning electron microscopy, various histochemical procedures for the localization of mineral ions, and analytical electron microscopy have been used to investigate the mechanisms inherent at the mantle edge for shell formation and growth in Amblema plicata perplicata, Conrad. The multilayered(More)
A study has been conducted to determine the ionic and metabolic requirements for full expression of the hydroosmotic response to antidiuretic hormone in the toad urinary bladder. By appropriate manipulation of incubation conditions it can be shown that there is a pool of serosal sodium necessary for a full hormone response. This serosal sodium pool is not(More)
All cells that comprise the epithelium of the toad urinary bladder were found to contain small ovoid to tubular membrane-bound bodies with a finely granular matrix. Such organelles were devoid of dense cores (nucleoids). These microperoxisomes reacted positively when incubated for the demonstration of catalase or malate synthase activity. In the toad liver,(More)
Periodontal soft tissues were cleaved from freshly extracted human teeth. Tissues were then prepared for subsequent biochemical and morphological studies according to the following plan: 1) immediate immersion in liquid nitrogen for the biochemical assay of superoxide dismutase (SOD); 2) immediate fixation prior to routine preparation for routine(More)
Evidence for the glyoxylate cycle in the mammalian rat liver was sought. Activity of two unique glyoxylate cycle enzymes, isocitrate lyase and malate synthase, was found in rat liver homogenates. Vitamin D3 treatment of rachitic animals produced a five- and fourfold increase, respectively, in the activity of these enzymes. Vitamin D3 also increased the(More)
A cytochemical technique for the electron microscopic localization of calcium adenosine triphosphatase (Ca-ATPase) was utilized to localize this enzyme in the enterocytes of rachitic and vitamin D-replete chicks. In animals treated with cholecalciferol (CC, vitamin D3), an electron-dense reaction product was located along the basolateral membranes of the(More)
The scanning electron microscope has been used to describe the morphology of the mature shell in a fresh-water bivalve. The structure of the organic and inorganic components within the nacre, the myostracum, and the prismatic layer is described. A transitional or intermediate zone, interposed between the prismatic layer and the nacre, was identified. In(More)
The structure of the periostracum in the fresh-water mussel Amblema has been described using light microscopy, transmission elec;ron microscopy, and scanning electron microscopy. The structure and evolutive course of the periostracum was studied along its entire length, from the periostracal groove until it forms the tough outer covering of the shell. At(More)