D A Samuelson's research while affiliated with University of Florida and other places

Publications (93)

Article
Full-text available
Zinc transporters have been characterized to further understand the absorption and metabolism of dietary zinc. Our goal was to characterize zinc transporter Slc39a11 (ZIP11) expression and its subcellular localization within cells of the murine gastrointestinal tract of mice and to determine if dietary zinc regulates ZIP11. The greatest ZIP11 expre...
Article
In all vertebrate species examined, anal glands have been observed. These glands can be found anywhere along the anal canal and are generally a combination of apocrine and sebaceous adenomeres. They are used for signal expression in both terrestrial and aquatic settings. The goal of this study was to determine the morphology of the anal glands in t...
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Objective: To provide measurements of globe dimensions and describe morphological characteristics of the cetacean globe with an emphasis on Bowman's layer and encapsulated sensory corpuscles (ESC) for available cetacean species. Animal studied: Cetacean globes housed at the Comparative Ocular Pathology Laboratory of Wisconsin from various odonto...
Article
Formalin preserved ocular-associated anterior adnexa tissues from five necropsied Asian elephants (Elephas maximus) were dissected with attention to the palpebrae, conjunctiva, nictitating membranes, nasolacrimal ducts, and periocular glandular tissues. Gross and histologic examination revealed that lacrimal and tarsal glands were not present. Evid...
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Objective  To describe the technique of deep anterior lamellar keratoplasty (DALK) with Descemet's membrane (DM) exposure in horse eyes. Also, to compare the efficacy and safety of viscodissection and big-bubble techniques for DALK. Animals studied  Thirty-four ex vivo horse eyes. Procedure  Deep anterior lamellar keratoplasty was performed in 34 e...
Article
Purpose: We compared the anti-fibrotic effects of single versus multiple postoperative injections of saratin following glaucoma filtration surgery (GFS) in the rabbit model. Methods: The experiment was in two parts. To determine the optimal frequency for postoperative therapy, seven New Zealand White (NZW) rabbits received an injection of sarati...
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Full-text available
Late complications can occur with use of current antimetabolites to prevent scarring following glaucoma filtration surgery (GFS). Safer, more targeted, anti-fibrosis agents are sought. The protein saratin has been shown to exhibit anti-fibrotic and anti-thrombotic properties in response to injury, but had not been used for glaucoma surgery. The goa...
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To compare the morphology of the uveoscleral (US) outflow pathway in normal and glaucomatous canines. 10 normal beagles, 10 beagles with inherited primary open-angle glaucoma, 4 cocker spaniels with spontaneous glaucoma. Formalin-preserved globes were sectioned tangentially and sagittally and treated with H&E, Masson's trichrome, or elastin stains...
Article
To investigate the uveoscleral (US) pathway in the normal eyes of four domestic spp.: the cat, pig, cow and horse by examining the comparative anatomical structure of anterior US pathway. Four cats, ten pigs, four cows, eight horses. Formalin-preserved specimens from anterior uveas of the cat, pig, cow and horse were embedded and serially sectioned...
Article
Purpose: Excessive scarring leading to failure of the filtering bleb continues to be a major problem after glaucoma filtration surgery. This study examines the antifibrotic effects of the anti-S1P monoclonal antibody LT1009 (Sonepcizumab) in prolonging bleb survival in a rabbit model of glaucoma filtering surgery. Methods: The frequency of LT100...
Book
This book provides systematic coverage of small animal ophthalmology via randomized self-assessment case presentations: integrated questions, superb illustrations, color photos, imaging, diagrams, tables, and detailed explanatory answers. The authors have emphasize the more common ophthalmic conditions presented to veterinarians in practice with 25...
Article
Tonometric and tonographic techniques were evaluated in the normal pony and compared to other species. Applanation tonometry was utilised to calculate the ocular ridigity of the normal equine eye. The mean intraocular pressure for the pony eye was established as 23.5 mm Hg (sd ±4.5). Comparing the non-anaesthetised and anaesthetised pony eye (xylaz...
Article
Impairment of skin barrier function has been hypothesized in canine atopic dermatitis (AD). In this prospective, controlled study, the ultrastructure of the upper epidermal layers was investigated using an experimental model of canine AD. Seven atopic Beagles sensitized to Dermatophagoides farinae and four healthy Beagles were used as controls. Bot...
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To determine using light and scanning electron microscopy if treatment with CO2 photokeratotomy alters the corneal endothelium in healthy dogs. Eight surgery laboratory dogs were determined to be free of ocular abnormalities. Under general anesthesia, the left eye of each dog was treated in a quadrant from 12 to 3 o'clock with the CO(2) laser in a...
Article
In human atopic dermatitis (AD), impairments in skin barrier function are emphasized and hypothesized to increase risk of allergic sensitization. Filaggrins, crucial proteins for keratinization, are decreased in lesional and nonlesional human atopic skin. As canine AD shares numerous similarities with the human counterpart, this study aimed to eval...
Article
Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease caused by complex interactions between genetics and environmental factors. In human beings, impairment of the skin barrier is demonstrated and thought to be responsible for enhanced penetration of allergens and increased risk for allergic sensitization. Once inflammation is tri...
Article
The replacement of the normal endothelial cell morphology with formation of a fibrocellular posterior collagenous layer by the corneal endothelium was demonstrated in an eight-year-old male German shepherd dog with bilateral progressive corneal oedema. Descemet's membrane was multilaminar and thickened. The ultrastructural findings in this dog are...
Article
The presence of myocilin was investigated in a colony of Beagles, a canine model for inherited primary open-angle glaucoma (POAG). The myocilin protein was localized in the normal and glaucomatous canine eyes by immunohistochemistry and immunocytochemistry. Paraffin- and plastic-embedded specimens from the anterior uveas of 10 Beagles with inherite...
Article
It has been recently demonstrated that trabecular meshwork (TM) cells within the canine iridocorneal angle (ICA) contain smooth muscle actin (smA) and possess contractile abilities that probably alter aqueous outflow. As the number of trabecular meshwork cells in glaucomatous canine eyes have been found to be less than those in age-matched nonglauc...
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Full-text available
Corneal avascularity-the absence of blood vessels in the cornea-is required for optical clarity and optimal vision, and has led to the cornea being widely used for validating pro- and anti-angiogenic therapeutic strategies for many disorders. But the molecular underpinnings of the avascular phenotype have until now remained obscure and are all the...
Article
To examine the anatomy of the ciliary body in the West Indian manatee (Trichechus manatus), paying close attention to its vascularization and to compare to those of its distant relative, the African elephant (Loxodonta africana), the amphibious hippopotamus (Hippopotamus amphibius) and the aquatic short-finned pilot whale (Globicephala macrorhynchu...
Article
To examine the angioarchitecture of the ciliary body in the West Indian manatee (Trichechus manatus), through the use of three-dimensional reconstruction. Specimens from West Indian manatee were preserved in 10% buffered formalin, embedded in paraffin, serial sectioned and stained by Masson trichrome for light microscopic three-dimensional reconstr...
Article
Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005.
Article
The cornea of the Florida manatee is unique and unusual in its anatomy in that blood vessels have been found throughout. In all other animal species, this is considered a pathological condition impeding vision, and is usually caused by injury or trauma. The purpose of this study was to more clearly describe corneal vascularization by examining the...
Article
The most common reason for long-term failure of glaucoma filtering surgery (GFS) is scarring of the external filtering "bleb" tissues. The identification of the factors that mediate this process, as well as the development and initial testing of new therapies to limit scarring is enhanced by the use of appropriate animal models. The standard animal...
Article
Zn homeostasis in animals is a consequence of avid uptake and retention, except during conditions of limited dietary availability, and/or factors such as parasites, which compete for this micronutrient or compromise retention by the host. Membrane proteins that facilitate Zn transport constitute the SLC30A (ZnT) and SLC39A (Zip) gene families. Beca...
Article
Intestinal epithelial tight junction (TJ) barrier dysfunction may lead to inflammation and mucosal injury. Glutamine (GLN) plays a role in maintenance of intestinal barrier function in various animal models and critically ill humans. Recent evidence from intestinal cell monolayers indicates that GLN maintains transepithelial resistance and decrease...
Article
Using a gastrostomy-fed (GF) rat infant "pup-in-a-cup" model, the effects of protein deprivation and supplemental glutamine (Gln) and glutamate (Glu) were examined to test the hypothesis that Gln decreases the proinflammatory response induced by LPS in the developing infant rat small intestine. Four groups of 6- to 7-day-old pups were fed a rat mil...
Article
Objectives: The phenomenon of 'eye-shine' is seen in a variety of animal species, and is generally thought to be related to the presence of an intraocular reflecting structure, the tapetum lucidum. The tapetum lucidum is a biologic reflector system that is a common feature in the eyes of vertebrates. It normally functions to provide the light-sens...
Article
To date, our knowledge of the canine trabecular meshwork (TM) with regard to contractility is incomplete. It is important to understand the potential contractile capability within the TM and possible changes associated with spontaneous hypertensive glaucoma. To that end we have examined the presence of actin, including smooth muscle (SM) actin, in...
Article
To determine the effect of retinal ganglion cell axotomy on the thickness of inner plexiform, inner nuclear, and outer plexiform layers, as well as the densities of short- and middle-to-long-wavelength cones, in the porcine retina. Unilateral retinal ganglion cell axotomy was performed in seven domestic pigs by either surgical optic nerve section o...
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Full-text available
Between September 1997 and March 1998, a severe skin, eye, and mouth disease was observed in a population of dusky pigmy rattlesnakes (Sistrurus miliarius barbouri), at the Lake Woodruff National Wildlife Refuge in Volusia County, Florida (USA). Three affected pigmy rattlesnakes were submitted for necropsy. All snakes had severe necrotizing and pre...
Article
The iridocorneal angles of prepared eyes from the West Indian manatee, short-finned pilot whale, hippopotamus and African elephant were examined and compared using light microscopy. The manatee and pilot whale demonstrated capacity for a large amount of aqueous outflow, probably as part of a system compensating for lack of ciliary musculature, and...
Article
Full-text available
Between Septeniber 1997 and March 1998, a severe skin, eye, and mouth disease was observed in a population of dusky, pigmy rattlesnakes (Sistrurus miliarius barbouri), at the Lake Woodruff National Wildlife Refuge in Volusia County,, Florida (USA). Three affected pigmy rattlesnakes were submitted for necropsy. All snakes had severe necrotizing and...
Article
To determine the clinical characteristics of possible inherited cataract in the Bichon Frise breed. These characteristics include the relative frequency, gender effects, site of first cataract formation, age of onset, relationship of age to cataract maturity, and other concurrent pre- and postoperative ophthalmic diseases. Four different population...
Article
Full-text available
Between September 1997 and March 1998, a severe skin, eye, and mouth disease was observed in a population of dusky pigmy rattlesnakes (Sistrurus miliarius barbouri), at the Lake Woodruff National Wildlife Refuge in Volusia County, Florida (USA). Three affected pigmy rattlesnakes were submitted for necropsy. All snakes had severe necrotizing and pre...
Article
Topical vecuronium bromide (Norcuron) and combinations with atropine and phenylephrine, were evaluated as mydriatics in juvenile double-crested cormorants (Phalacrocorax auritus). Nine cormorants were treated with each of four protocols: 1% atropine; 4 mg/mL vecuronium bromide (total 0.16 mg/eye); atropine with vecuronium; and atropine, 2.5% phenyl...
Article
Full-text available
Histochemical reactions for lipid hydroperoxides (LHP) using indophenol, benzidine, or phenylendiamine as the electron donor have been described previously for auto-oxidized adipose (1) and neuronal (2) tissue. More recently, tetramethylbenzidine (TMB) has been proposed as another chromagen (3). The usefulness of the TMB reaction for ultrastructura...
Article
Light damage research began during the early years of laser light exploration. There is a clear and significant literature that identifies an easily demonstrated retina-pigment epithelium pathology which is associated with short wavelength exposures below 520 nm. Recent interest has expanded because of the growing evidence for a blue light contribu...
Article
Objective: The canine iridocorneal angle contains an operculum, which is similar to that in nonhuman primates and consists of a peripheral extension of the inner cornea that overlies the anterior-most portion of the corneoscleral trabecular meshwork. This region contains cells, the Schwalbe line's (SL) cells, that have been found to have secretory...
Article
Metallothionein and zinc have been implicated in cellular defense against a number of cytotoxic agents. With respect to the free radical-generating hepatotoxin carbon tetrachloride, conclusions about a defensive role were reached from in vitro studies, in vivo studies using inducers of metallothionein and studies using injections of pharmacological...
Article
Sirenians, including Florida manatees, possess an array of hairs and bristles on the face. These are distributed in a pattern involving nine distinct regions of the face, unlike that of any other mammalian order. Some of these bristles and hairs are known to be used in tactile exploration and in grasping behaviors. In the present study we character...
Article
Purpose To use immunohistochemical techniques to identify and localize the structural macromolecules of the extracellular matrix (ECM) of the normal adult equine lamina cribrosa in order to make comparisons to the extracellular matrix of the lamina cribrosa of horses with glaucoma.Methods Normal eyes of five adult horses between 5 and 10 years of a...
Article
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...
Article
The objective of the research was to compare the efficacy of Optisol-GS (OGS, Bausch & Lomb Surgical, Irvine, CA, USA) with triple antibiotic ophthalmic solution (neomycin-polymyxin B-gramicidin, NPG; Bausch & Lomb, Tampa, FL, USA) in preserving the viability of corneal endothelial cells. The study subjects were thirty young to middle-aged dogs wit...
Article
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...
Article
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 me...
Article
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...
Article
The spontaneous glaucomas have been documented in a number of animal species, with those in the dog having the highest frequency and second to that in humans. In all animal species studied, these primary glaucomas appear associated with impairment of the aqueous humor outflow and not hypersecretion of aqueous humor. In response to either acute or c...
Article
In the past, the principal techniques of choice for analyzing tissue for various inorganic atomic species have been colometric and via atomic absorption spectrophotometry (1). Although both methods can be accurate and precise when performed in the same laboratory, there are disadvantages, which include interlaboratory variability in results owing t...
Article
To determine whether photoreceptor outer segments can be found in aqueous humor from dogs with rhegmatogenous retinal detachment (RRD). Case series. 4 dogs with unilateral RRD, 2 dogs with bilateral RRD, 1 dog with unilateral non-RRD, and 1 dog with glaucoma without retinal detachment. Aqueous humor samples were fixed in 2% glutaraldehyde and exami...
Article
Cysteine-rich intestinal protein (CRIP) is a LIM (cysteine-rich motif of leu-11, isl-1, and mec-3 genes) domain protein with a double zinc finger motif. The protein is abundantly expressed in the intestine, peritoneal macrophages, and peripheral blood mononuclear cells. The function of CRIP is not known. The purpose of this study was to determine t...
Article
Purpose: Horses with glaucoma retain functional vision in spite of ophthalmic evidence of severe optic nerve atrophy. We investigated whether regional differences in the morphology of the scierai lamina cribrosa might be responsible for protection of the optic nerve axons under conditions of elevated IOP. Methods: Trypsin digestion and SEM were uti...
Article
Cysteine-rich intestinal protein (CRIP) is a double zinc finger (LIM domain) protein that is developmentally regulated but has an unknown function. CRIP is highly expressed in the intestine, but expression is low in liver. To determine if CRIP expression is regulated under altered physiological status, we used CCl4-induced injury as a model to prod...
Article
Introduction: This study investigated the effect of peri-bleb subconjunctival injection of TGF-beta on induced bleb leaks in rabbits. Methods: Posterior lip sclerotomies with mitomycin C (0.4 mg/ml) were performed in New Zealand White Rabbits. A standardized stab incision was done over the sclerotomy on POD #7. On POD #8, 0.2 ml of either BSS or TG...
Article
The beagle dog with hereditary primary open-angle glaucoma, unlike other animal models of human glaucoma, possesses a slowly progressive, sustained elevation of intraocular pressure. The effects of this insidious elevation in intraocular pressure on the axons of the optic nerves of three beagles at early stages of glaucoma and two beagles with adva...
Article
Acute intestinal inflammation was established in rats by intraluminal administration of acetic acid into loops of distal ileum, proximal jejunum or ascending colon. The study included two control groups of intact (untreated) rats and sham-operated (saline-treated) rats for each intestinal segment. A third group of rats received acetic acid. Histolo...
Article
Rhesus monkeys from the closed Cayo Santiago colony of the University of Puerto Rico demonstrate elevated (> or = 22 mm Hg) intraocular pressure in a pattern which significantly favours certain maternal lineage groupings. The colony had remained genetically pure since 1938. Of nine matriarchal lineages (matrilines) examined, two had an incidence of...
Article
Retinal-choroidal tissues were collected from older sows that were fed either control (100% Zn), intermediate zinc (59% Zn) or low zinc (21% Zn) diets for a 6-month period. The tissues were prepared for elemental energy dispersive X-ray analysis and examined by scanning transmission electron microscopy. Melanosomes of the retinal pigment epithelium...
Article
The anterior chambers in 16 dogs with normotensive eyes and 3 Beagles with glaucomatous eyes were treated with 0, 25, 50, or 100 IU of bovine testicular hyaluronidase. Aqueous outflow resistance was then determined by constant-pressure perfusion of 0.9% NaCl solution for 30 or 60 minutes. In normotensive eyes, 25, 50, or 100 IU of hyaluronidase sig...
Article
Ovine ceroid-lipofuscinosis (OCL) is one animal model for the human condition, and because autofluorescent lipopigments are prominent in the brain and eye, it may also prove useful as a model for aging. For example, a progressive decline in electrical recording from brain and retina are observed in both aging and OCL. Samples of retinal and retinal...
Article
Ultrastructural examination of optic nerve capillaries in the canine lamina cribrosa revealed many spherical, membrane-bound, electron-dense inclusions that closely resembled Weibel-Palade bodies, in pericytes and endothelial cells of preglaucomatous, early, moderately, and advanced affected Beagles with hereditary primary open-angle glaucoma. This...
Article
Optic nerve axoplasmic flow is known to be impaired at the scleral lamina cribrosa in Beagles with hereditary primary open-angle glaucoma and is similar to the condition in human beings. Trypsin and detergent digestion to remove all neural, vascular, and glial cellular tissue revealed a well-developed scleral lamina cribrosa in the normal dog in th...
Article
Scanning electron microscopy of vascular corrosion casts of the optic nerve region in normal and glaucomatous Beagles demonstrated that the blood supply to the laminar optic nerve is derived from short posterior ciliary arteries, cilioretinal arteries, and longitudinal pial vessels. The short posterior ciliary arteries formed a ring of striated pil...
Article
The iridocorneal angle of the horse was anteriorly lined by a pectinate ligament, consisting of several layers of vertically oriented collagenous beams, that were interrupted by a network of extracellular spaces. The anterior chamber angle consisted mostly of a large uveal trabecular meshwork that was composed of widely-spaced, thick trabeculae. Th...
Article
Spontaneous glaucoma in the beagle was exhibited after 6 months of age by elevated intraocular pressures and open iridocorneal angles followed by secondary changes. In order to appreciate alterations of the aqueous outflow apparatus in dogs with this autosomal recessive disorder, the eyes of beagles with inherited glaucoma at ages 1 day through 34...
Article
The anterior vasculature of the pony eye was examined by the corrosion cast method. The anterior segment of the pony eye has a vascular pattern which is similar but distinct from that of other mammalian species. Large iridal veins collateralized directly with the anterior vortex venous system. The intrascleral plexus was present but formed a fine,...
Article
The Krupin-Denver valve was implanted unilaterally in 2 normotensive and in 6 glaucomatous Beagles. The fellow eye of each dog had an external trabeculectomy. Before and after surgery, all dogs were evaluated serially by gonioscopy, biomicroscopy, tonometry, and tonography. The valve implant remained patent in 2 normotensive and in 2 glaucomatous B...
Article
Normal drainage of aqueous humor from the anterior chamber of the equine eye occurred through conventional and unconventional routes. To determine the degree of uveoscleral outflow in the pony, 1- and 3-microns (diam) microspheres were perfused through the anterior chamber for 60 and 90 minutes. Two eyes were treated with pilocarpine before perfusi...
Article
A slow-growing xanthomatous tumour which diffusely infiltrated the iris and ciliary body of a dog was composed of large, pale, vacuolated cells which contained scattered fine pigment granules. Electron microscopy revealed coalescing vacuoles, lamellar membranous structures, and small groups of melanosomes in the cytoplasm, suggesting melanocytic or...
Article
Aqueous humor leaves the anterior chamber through 2 pathways: the trabecular meshwork of the iridocorneal angle and the unconventional uveoscleral route. In the latter route, aqueous humor leaves the anterior chamber, passes caudally through the trabecular meshwork and sclerociliary cleft to enter the supraciliary and suprachoroidal spaces. The flu...
Article
Normal drainage of aqueous humor from the anterior chamber of the canine eye occurred through the angular aqueous plexus and uveoscleral route. In order to understand more clearly, uveoscleral outflow with regard to larger sized tracer particles and the possible influence that varying intraocular pressure (IOP) may have on them, microspheres of 3 s...
Article
In uveoscleral outflow, aqueous humor leaves the anterior chamber and passes caudally through the trabecular meshwork and the sclerociliary cleft to enter the supraciliary and suprachoroidal spaces. The fluid is then absorbed by choroidal and scleral circulations. Using 3H-labeled dextran, uveoscleral outflow was quantitated in normotensive and gla...
Article
Microspheres of 3 different sizes were infused separately into the eyes of dogs with normotensive and hypertensive intraocular pressures. Latex spheres (0.5 or 1.0 micron) or 3.0 micron plastic spheres were added to Ringer's solution with 6% gelatin. Initially, this mixture was injected into the anterior chamber of dogs with intraocular pressures o...