D W Samuelson

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The spatial distribution and densities of photoreceptors in seven whole-mounted porcine retinas were studied and maps illustrating photoreceptor topography were constructed. Total photoreceptor densities ranged from to 83 000 to 200 000 cells/mm2, with a mean of 138 500 cells/mm2. Cone densities ranged from 39 000 (area centralis) to 8500 cones/mm2(More)
Purpose To describe the clinical appearance of corneal epithelial cell microerosions associated with keratomycosis in the horse. METHODS: Retrospective clinical study. RESULTS: Multifocal, punctate, superficial corneal opacities with positive rose bengal retention were noted in six horses with presumed 'viral keratitis'. Faint fluorescein staining was also(More)
The effects of low zinc nutrition and aging on central choroidal melanocytes were examined in the pig. Three populations of pigs (young, pregnant and aged), were maintained on either control (C) or low zinc (LZ) diets. Twenty-five weanling boars were sacrificed at 2, 4, 8, 10, and 12-month intervals, and nine pregnant sows and eight aged sows were(More)
The effects of low zinc nutrition and aging on central choroidal melanosomes were examined in the pig. Melanosomes of central choroidal melanocytes were morphologically and morphometrically examined in three populations of pigs (young, pregnant and aged), that were maintained on either control (C) or low zinc (LZ) diets. In C groups, the typical melanosomes(More)
The objective of this study was to determine the effectiveness of testosterone in suppressing estrus in the bitch, and of cabergoline in shortening the length of the subsequent anestrous period. In Experiment 1, 12 diestrual Beagle bitches were randomly divided into two groups when plasma progesterone (P(4)) concentration was <1 ng/ml (Day 0). Starting on(More)
Sepsis is a common cause of morbidity and mortality. Neutrophils are the major defense against bacterial invasion, and granulocyte colony-stimulating factor (G-CSF) augments both neutrophil number and function. In our study, 160 rabbits were inoculated transtracheally with 0.5 mL of a solution containing 10(4) colony forming units per milliliter of(More)
BACKGROUND During less invasive coronary bypass operations on the beating heart, as well as conventional operations using continuous warm cardioplegia, a precise anastomosis is facilitated by a bloodless field. To maintain a clear field, many surgeons use high-flow gas insufflation. However, the potentially damaging effects of gas insufflation on coronary(More)
We will discuss several recent advances in agent-based modeling, with applications to mass egress and wide-area evacuations following disasters. These advances include: efficiency improvements in specifying people's identification and selection of exit routes, making it possible to handle up to 70,000 people-agents; incorporation of new crowd movement(More)
OBJECTIVE Mechanical cardiac stabilization is beneficial for precise coronary anastomoses on the beating heart. However, the effect of mechanical cardiac stabilization on hemodynamics, left ventricular performance, and the degree of injury to underlying tissue are uncertain. METHODS Twelve swine (20-30 kg) underwent median sternotomy and a mechanical(More)
OBJECTIVE To determine the frequency of gastrointestinal toxicity due to intravenous (IV) erythromycin and to attempt to decrease this toxicity by prolonging the infusion time of erythromycin and/or pretreating with the peripheral anticholinergic, glycopyrrolate 0.1 mg IV. DESIGN Randomized, double-blind, placebo-controlled trial. SETTING General(More)