THERE ARE THREE REGIONS IN THE STOMACH OF OREOCHROMIS NILOTICUS.
EFFECTS OF THE LIVER OF RATS FED PCB 28: AN ULTRASTRUCTURAL AND BIOCHEMICAL STUDY. Singh, Amreek and Ih Chu, Atlantic Veterinary College, Charlottetown, PE, Canada ClA 4P3 and Environmental Health Directorate, Tunney's Pasture, Ottawa, ON, Canada KlA OL2.
Polychlorinated biphenyls (PCBs) are a family of 209 compounds that were used as industrial coolants in the 1 970s. Despite a ban for two decades on their manufacture, these toxicants persist in the food chain. PCB congener #28 (2,4,4'-trichlorobiphenyl) was given to Sprague-Dawley weanling rats of both genders in diets prepared by mixing the congener in 4% corn oil, which was added to "Lab Chow". The diets contained 0.05, 0.5, 5, or 50 ppm congener; animals receiving "Chow" and only corn oil served as the controls. Liver tissue was harvested at 13 weeks of feeding for electron microscopy and biochemical analysis. Most conspicuous hepatocyte changes included increase of smooth endoplasmic reticulum profiles and elevation of peroxisome numbers in the animals regardless of the gender, and mitochondrial abnormalities in the females only. Cristae in atypical orientation comprised mitochondrial aberrations. Alterations were revealed in the liver of animals of 5 and 50 ppm groups. Ethoxyresorufin-O-deethylase activity was significantly (statistically) high in the animals of the 50 ppm groups. We concluded that the female animals were more sensitive than the males to this congener. A no observable adverse effect level (NOAEL) was believed to be 0.5 ppm for PCB congener #28.
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THERE ARE THREE REGIONS IN THE STOMACH OF OREOCHROMIS NILOTICUS. Caceci1, T., H.A. El-Habback2, and S.A. Smith1, Departments of 1Biomedical Sciences & Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA 240610442; and 2Histology & Cytology, Cairo University, Giza, Egypt.
The stomach of Oreochromis niloticus, was divided into distinct initial, middle and terminal regions. Grossly it was T-shaped: the initial and terminal portions formed the two horizontal arms of the T and the middle portion the vertical part. The initial and terminal regions were connected, with the middle region forming a large diverticulum communicating with the first two at the junction. The initial region was shorter than the middle region, longer than the terminal one, smooth surfaced, lacking gastric pits, and continuous with the esophagus. The gastric epithelium consisted of simple columnar cells without goblet cells. There were glandular regions in its lamina propria. Initial region glandular tissue was distinguishable from the surface epithelium; these glands were lined by high cuboidal epithelium with basally situated flat nuclei, positive to PAS and alcian blue at pH 1 and 2.5. The middle region was longer than the initial one. Its mucosa formed prominent gastric pits lined by epithelium similar to that of the initial region. This region contained a type of gland which filled most of the lamina propria. These simple tubular glands opened into the gastric pits and were lined by truncated acidophilic cells which were PAS- and AB-negative. The terminal part of the stomach was very short; the mucosa was slightly folded and lacked gastric pits or mucous glandular cells. The lamina propria was more prominent than in the other two regions and contained no glands. The epithelium of the portion was simple columnar and contained goblet cells at its junction with the first part of the intestine. The tunica muscularis of the stomach contained skeletal muscle in all three regions, usually intermingled with smooth muscle fibers. Skeletal muscle fibers were observed in the first portion of the small intestine, near the junction with the stomach.
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THE PATELLA OF SELECTED BATS: OCCURRENCE OR ABSENCE, AND ASSOCIATED MODIFICATIONS OF THE QUADRICEPS FEMORIS TENDON. Smith, Bonnie J., Steven D. Holladay, and Stephen A. Smith, Virginia-Maryland Regional College of Veterinary Medicine, Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0442.
Species from the two suborders of bats (Megachiroptera and Microchiroptera) were examined to determine the presence or absence of a bony patella, and the distribution of this feature among bats. Study of seven megachiropteran species representing four genera, as well as six microchiropteran species representing six genera, was undertaken using gross, radiographic, and histologic examination. A bony patella was observed in all six microchiropteran and in three megachiropteran species. The tendon of the quadriceps femoris muscle in microchiropteran species was composed mainly of dense regular connective tissue. The quadriceps tendon in megachiropteran species with a patella contained an abundance of fibrocartilage and hyaline cartilage, unlike the quadriceps femoris tendon of the Microchiroptera or a laboratory mouse examined for comparison. Four species of the megachiropteran genus Pteropus lacking a bony patella displayed a similar occurrence and distribution of fibrocartilage and hyaline cartilage within the quadriceps tendon as seen in the other bats. In reference to this singular feature, Pteropus is unique among the representatives of megachiropteran and microchiropteran genera examined here.
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MAMMALIAN OVIDUCT? WHAT NEXT, AVIAN DENTITION? Habel, Robert E., Department of Veterinary Anatomy, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-6401.
The term mammalian oviduct is an oxymoron: if it is a placental mammal, as all of our domestic mammals are, it does not lay eggs and does not have an oviduct; it has uterine tubes. These two terms do not mean the same thing and are not interchangeable, for the following reasons: 1) Gross anatomy. The oviduct is a major organ, unilateral in birds, which extends from the ovary to the cloaca. Uterine tubes extend from the ovary to the uterus only. 2) Embryology. The oviduct develops from the entire paramesonephric duct; the uterine tube, only from the cranial part. They are not homologous. 3) Histology. The mucosa of the oviduct contains branched tubular glands; the uterine tube has no true glands. 4) Physiology. The oviduct produces albumen, shell membranes, and the shell; the uterine tube, none of these. 5) Nomenclatural precedence. Fallopius, a student of Vesalius and a teacher of Fabricius, in his Anatomical Observations (1561) on the human female reproductive tract, chose the term tuba uterina because the Latin word tuba means trumpet, reflecting the similarity of the infundibulum to the flared bell of a trumpet. More than a century later, de Graaf, who discovered the function of the ovary and named the oviduct in his study of the hen, published his paper On the Human Reproductive Organs (1672). He used the terms tubae and tubae Fallopii because these were the established mammalian terms. Tuba uterina is the international term in the nomenclatures of gross anatomy since 1895, histology since 1965, and embryology since 1977. Eponyms like Fallopian were eliminated from the Nomina Anatomica in 1955. The English term uterine tube, while an inexact translation, is standard in medicine, approved by the Nomencl. Comm. of the Am. College of Theriogenologists in 1987.
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SPERM STORAGE TUBULES IN THE VAGINA OF THE OSTRICH STRUTHIO CAMELUS. Bezuidenhout, A.J., Department of Anatomy, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Republic of South Africa.
Sperm storage tubules have been described in a number of species of birds. The presence of these tubules in the Rhea has been mentioned, but no description of these structures in ratites is available. The purpose of this study was to determine the presence and morphology of sperm storage tubules in the vagina of the ostrich. The study was performed using conventional light and electron microscopic techniques. Sperm storage tubules were located in a 200 mm wide band of the vagina adjacent to the uterovaginal junction. The tubules were mostly branched and slightly coiled and lined by columnar epithelial cells. The cells contained a basal nucleus and displayed extensive apical junctional complexes. TEM revealed morphologically normal sperm in all the tubules examined.
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ADAPTATION OF THE LARYNGEAL CARTILAGES TO THE AQUATIC HABITAT OF THE BOWHEAD WHALE, BALAENA MYSTlCETUS. Schoenfuss, H.L., and D.J. Hillmann, Department of Veterinary Anatomy and Cell Biology, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8408)
The ungulates are the closest terrestrial relatives of the Bowhead Whale, Balaena mysticetus, a member of the suborder Mysticeti (Milinkovitch 1992, J. Evol. Biol. 5: 149-160). A comparative study of the structure of the larynx, as intermittent between respiratory and digestive systems, can provide information for the understanding of the evolutionary pressures that act on these two phylogenetic lineages. The larynx of the Bowhead Whale was compared with the larynx of the domestic pig, Sus scrofa domesticus, because the pig is the closest domestic relative of the whale and subsequently, as a domestic mammal, its larynx has been studied in detail. Several methods were used to examine six Bowhead Whale specimens that were obtained from native whale hunters of Barrow, Alaska. All four laryngeal cartilages showed significant differences when compared to the cartilages of the domestic pig. A prominent medial ridge is situated on the dorsal aspect of the epiglottis. The arytenoids are rod shaped and extend throughout most of the larynx with synovial articulations on the rostromedial aspect of the cricoid. The cricoid cartilage is incomplete and ventrally open. The cranial cornu of the thyroid cartilage are absent. Pronounced caudal cornu are present forming points of rotation with the caudolateral aspect of the cricoid. Partial fusion occurs between the cricoid cartilage and the first few incomplete tracheal rings. These structural components are employed to separate the digestive from the respiratory systems preventing accidental water intake into the respiratory system. The laryngeal cartilages are highly specialized, compared to those of the domestic pig, as an adaptation to the aquatic habitat of the Bowhead Whale.
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CALBINDIN-D9K EXPRESSION IN THE BOVINE PLACENTA: AN IN VIVO ANALYSIS. Reiswig, J.D. and N. Inpanbutr, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210-1092.
Calbindin-D9k is a vitamin D-dependent calcium binding protein first identified in mammalian intestinal epithelium. This protein is believed to function in the transport of calcium across the luminal epithelium. Recently, immunohistochemistry investigations within our lab have revealed that calbindin-D9k is also present in the bovine placenta of second and third trimester pregnancies. This protein has been identified using biotin-streptavidin-peroxidase immunohistochemistry within the maternal caruncular epithelium, the fetal cotyledonary epithelium, and the fetal trophoblastic binucleated cells. In this study, the density of the immunoreaction observed with light microscopy of second trimester (n=6) and term pregnancies (n=6) was compared using BioScan Optima 4.1 software. The density was significantly greater in the term pregnancies (LIGV = 0.949 O 0.350) than in second trimester pregnancies (LIGV = 0.2967 O 0.123) using the Mann-Whitney analysis (p=0.0131).
Total tissue concentrations of calbindin-D9k were evaluated using a dotblot immunobinding assay. A chemiluminescent detection system was used and the reaction was visualized by exposing the nitrocellulose membrane to X-ray film. Densitometric analysis of the radiograph was used to compare the sample homogenate with a known standard of calbindin-D9k. No difference in the total tissue concentration of calbindin-D9k was detected between second trimester pregnancies (134.7 Eg calbindin-D9k per mg total protein) and term pregnancies (116.18 Eg/mg). In second trimester pregnancies the maternal caruncular epithelium appears columnar while in the term pregnancies the epithelium is squamous. This change in cell shape may account for the increased intensity of the immunoreaction for calbindin-D9k observed in the term pregnancy, while total protein concentration was not effected.
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THE EFFECTS OF ATROPINE AND NEOSTIGMINE ON EQUINE PANETH CELL SECRETION: A LIGHT AND ULTRASTRUCTURAL IMMUNOCYTOCHEMICAL INVESTIGATION. Charalambous, A.C. and J. Masty, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210-1092.
The equine Paneth cell, enterocytus cum granulis acidophilis, is the major cell type present in the base of the equine intestinal glands. Paneth cells secrete a wide spectrum of antibacterial agents, including Iysozyme, responsible for the regulation of the intestinal microbial flora. Using Iysozyme immunoreactivity as a specific Paneth cell marker, the distribution of Paneth cells in the equine small intestine was quantitated and found to significantly (p=0.0001) increase in an aboral direction from duodenum to ileum. No differences (p=0.9576) were detected in the distribution of Paneth cells between the intestinal mesenteric and antimesenteric sites. The ultrastructural morphology of Paneth cells was also investigated. Immunoelectron labeling for Iysozyme revealed localization in the Paneth cell secretory granules, specifically within the granule's electron dense core and intermediate zone of lesser electron density. The granule lucent halo zone was devoid of Iysozyme labeling. The parasympathetic effects on the secretory mechanism of the equine Paneth cells were also investigated. To simulate a parasympatholytic effect, atropine at a dose of 0.03mg/ kg was administered subcutaneously. To mimic the stimulatory effect of parasympathetic activation, neostigmine at a dose of 0.02mg/kg was administered subcutaneously. Control animals received an injection of sterile saline at a dose of 0.03mg/kg. Changes in Paneth cell morphology and localization of Iysozyme, associated with treatment with these pharmacologic agents, were investigated at both the light and ultrastructural levels. In comparison to controls, Paneth cells from atropine treated horses exhibited strong Iysozyme immunoreactivity and were engorged with secretory granules. No Paneth cell exocytotic profiles were observed; the apical plasma membranes were intact indicative of the inhibitory effect of atropine on Paneth cell secretion. Massive degranulation and large vacuoles were observed in Paneth cells from neostigmine treated horses. Immunoreactive Iysozyme was localized in the crypt lumen of the equine intestinal glands. Lysozyme immunoreactivity was quantitated in the atropine, neostigmine, and control groups via an image analysis system.
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PHYSIOLOGICAL IMPLICATIONS OF MESOZOIC BONE HISTOLOGY. Dodson, Peter and Anusuya Chinsamy, Laboratories of Anatomy, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104.
Although organic compounds in bone deteriorate quickly after death, the mineral component is extremely stable during fossilization, and preserves with high fidelity microscopic details of anatomical structure and organization. Modern reptile bone is poorly vascularized and shows ample signs of seasonal alteration of growth rates, expressed in a series of zones and annuli, with or without lines of arrested growth (LAGs). Mammal and bird bone by contrast is richly vascularized and shows no signs of seasonal slow-down or cessation of growth. It has been known for many years that dinosaur bone is as richly vascularized as that of modern birds or mammals. This parallel has suggested to some that dinosaurs were warm blooded (i.e. tachymetabolic endotherms) like birds and mammals. New work on growth series of dinosaur by Chinsamy (1990, 1993) and Varricchio (1993) demonstrates the widespread occurrence of growth rings in dinosaur bone, especially in meat-eating dinosaurs, the putative ancestors of birds. Until recently, no living or fossil bird, including the Cretaceous Hesperornis, showed any sign of growth rings. Recently (Chinsamy et al., 1994), we reported growth rings in two primitive Cretaceous birds from South America, Patagopteryx and Enantiornithis. The histology of these birds suggests a fundamentally reptilian growth pattern, and we infer that high growth rates and fully modern metabolic rates evolved later in the evolutionary history of birds than had been presumed.
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ACTIVITY-DEPENDENT PLASTICITY IN ADULT RAT BRAIN. Hand, Peter J., Laboratories of Anatomy, Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104.
The "hardwired" adult central nervous system (CNS) was thought to be incapable of significant reorganization (plasticity) following a variety of peripheral nervous system (PNS) manipulations (damage, disuse, or enrichment). However, recent work in this laboratory has demonstrated that adult CNS is capable of robust reorganization following PNS damage or activity changes. We examined the adult neocortical effects of (1) chronic increase of peripheral receptor organ activation under different contexts and (2) chronic decrease in receptor activation. The precisely organized vibrissa-first somatosensory cortex (SI) pathway was selected and the (14C)-deoxyglucose method utilized to assess changes in the SI functional representation of the experimentally manipulated vibrissa receptor organ. Three types of vibrissa manipulations were performed: (1) daily mechanical activation of a single (C3) vibrissa (untrained group), (2) daily mechanical activation of C3 vibrissa (conditioned stimulus) + intraoral administration of a sucrose solution (unconditioned stimulus) during vibrissa activation (trained group), and (3) removal of competitive vibrissa effects in SI by unilateral clipping of all vibrissae, excepting C3 (SC3) which received its normal compliment of activation (selective disuse group).
The major findings were: (1) in SI of the untrained group, the size of and the amount of activity in the C3 functional representation (as compared to intra-animal controls) was decreased by 14% and 3.8%, respectively; (2) in SI of the trained group, the size of and the amount of activity in the C3 functional representation was increased by 14% and 3.3%, respectively; and (3) in SI of the vibrissa selective disuse group, the size of and the amount of activity in the SC3 functional representation was increased by 32% and decreased by 7%, respectively. In conclusion, these results demonstrate significant activity-dependent functional plasticity (and the dynamic nature) of vibrissae representation in the adult rat neocortex.
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REGENERATION OF THE LENS - EYE OF NEWT. McDevitt, David S., Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104.
The ability to regenerate the lens of the eye in adult vertebrates is restricted to a group of urodele amphibians. Complete removal of the lens in these animals is followed by formation of a new lens at the dorsal pupillary margin. The classical idea that the source of this regenerated lens is the dorsal iris epithelial cells now has strong experimental support. Notwithstanding the long history and intrinsic interest of this system, little is known concerning the causal factors of lens regeneration, or the biochemical composition of the regenerated lens. I would now like to report the progress which our laboratory has made in analysis of the regenerating lens, as well as to identify some of the paradoxes and dilemmas inherent in this phenomenon and their relation to iris and retinal tissues. It has been hypothesized that a neural retinal "factor" involved in lens regeneration acts indirectly, to preferentially shorten the cell cycle time in the dorsal iris epithelial cells in vivo as compared to ventral iris (which cannot regenerate a lens in vivo). This would permit the dorsal iris epithelial cells to go through the requisite number of cell cycles (6 to 7) for conversion into lens cells, before mitosis ceases once again in the iris epithelium. This interesting hypothesis does not, however, address itself to the paradox of dorsal iris competence vs. ventral iris incompetence to regenerate a lens in situ. It must also be presumed that any neural retinal "factor" must be available to both sectors of iris tissue. Evidence of growth factor involvement in regeneration of the lens will be discussed.
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VISCERAL NEURAXIS OF THE RAT BRAIN AS SEEN WITH PSEUDORABIES VIRUS. Miselis, Richard R., Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104.
Pseudorabies virus (PRV) is a neurotropic herpes virus which readily infects the rat brain. It progresses most rapidly in a retrograde manner and enters the central nervous system first via motor nerves, replicates in cell bodies and passes transsynaptically into axon terminals, and repeats this cycle again. Theoretically it should be possible to get to all neurons of the brain involved in modulating function of a specific viscus. We have applied this virus to mapping synaptically connected neural circuits innervating specific viscera. From well confined injections of individual structures of the alimentary canal we follow PRV through the autonomic or somatic nervous innervation into the brainstem or spinal cord, to the hypothalamus, basal ganglia and neocortex. Analysis of this data permits determining and comparing the exact neural circuitry involved in controlling organs of the alimentary canal. Following gastric, esophageal or cecal injections we follow PRV to specific viscerotopically localized primary motoneurons in the brainstem (dorsal or ventral vagal nuclei) and from there to a widely distributed set of second order afferents within the brainstem that agree with previous reports using classical neuroanatomical tracers. Labeling of neurons then appears more rostrally: for example, the paraventricular nucleus of the hypothalamus and the medial subnucleus of the central nucleus of the amygdala. Following this labeling occurs in the insular neocortex and in the circumventricular organs of the lamina terminalis. To determine the major route of PRV into the forebrain from the stomach we have made subdiaphragmatic vagotomies to eliminate the parasympathetic pathway. This manipulation, surprisingly, eliminated most of the forebrain labeling indicating that most of the forebrain modulation of gastric function is through the parasympathetic innervation. We have also made mutant forms of PRV and performed double labeling experiments to determine the location and distribution of neurons that modulate more than one organ.
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THE NATURE OF REM SLEEP. Morrison, Adrian R., Laboratory for Study of the Brain in Sleep, Laboratories of Anatomy, Department of Animal Biology, University of Pennsylvania, Philadelphia, PA 19104.
Our laboratory has been fascinated by the mystery of REM, addressing specifically why its various physiologic features appear together as they do, i.e., activated EEG, waves recorded in the lateral geniculate body (PGO waves), and muscle atonia. We think that these features group together because the fundamental aspect of REM is reticular formation activation reminiscent of that associated with orienting in wakefulness. Lesions in the pons remove atonia and permit different behaviors during REM without atonia (REM-A). Only behaviors seen in alert wakefulness occur in REM-A: orienting, search, startle, predatory attack; never grooming or eating. PGO waves, normally spontaneous in REM, can be elicited by loud tones in all states. Because they also can be evoked by stimulation of the mesencephalic reticular formation, we reason that PGO waves are phasic signs of alerting. We believe the large spontaneous PGO waves in REM represent phasic activations of the reticular formation that would be associated with orienting in wakefulness. We think the paralysis of REM is an exaggeration of the suppression of movement in normal wakefulness when a cat orients. The brain is "hard-wired" so that reticular activation leads to some degree of motor suppression, slight during orienting in W and profound during REM. Lesioned cats are excessively active in both wakefulness and REM-A, indicating that a break in that linkage has occurred. We wish to understand the underlying neural basis of PGO waves and, ultimately, the control of alerting. Understanding the abnormal hypervigilance of post-traumatic stress disorder may be an outcome. We are investigating both serotonergic and GABA-ergic mechanisms via local infusions of agonists and antagonists into the putative brainstem PGO wave generator region in the pons, as well as in the amygdala, a limbic system structure projecting heavily to the dorsal pons.
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TEACHING-LEARNING IN APPLIED ANATOMY - A METHOD FOR IMMEDIATE FEEDBACK. McClure, R. C. and G.M. Constantinescu, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO 65211.
Immediate feedback is one of the positive tenets of the teaching - learning process. A method for immediate feedback has been perfected for helping veterinary medical students learn the anatomy and procedure for producing local anesthesia, utilizing post mortem horse limbs and the horse head, as examples.
Students utilize appropriate syringes and needles to inject a dye (methylene blue or Janus green) to mark the end of the needle in relation to the selected nerves. An illustrated guide is used to locate the site for the "nerve block". After making the injection, the student can dissect to determine the exact relation of the dye to the nerve.
Students are given syringes, needles, dyes, and dissection instruments along with a handout. The handout includes a description of each "Nerve Block", its application, anatomy, structures supplied, etc., along with accompanying illustrative material. Students appreciate the immediate feedback with this approach to teaching-learning.
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CLINICAL APPROACH ON ANATOMIC STRUCTURES - NERVE BLOCK ANESTHESIA IN THE THORACIC LIMB OF THE HORSE. Constantinescu, G.M., and R.C. McClure, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO 65211.
The landmarks for blocking the (cutaneous) nerves in the thoracic limb have been established by taking into consideration bones, joints, muscles, intermuscular grooves and other palpable structures, such as the chestnut, the lacertus fibrosus and the coronary border of the hoof wall. All those landmarks have been checked on live specimens, some of the landmarks being subject to minor adjustments. After adjustments have been made with the limbs flexed or extended, the clinical approach for each nerve has been determined. The nerves were "blocked" on cadavers by injecting several drops of dye, and then dissecting the structures to expose the "blocked" nerves. The nerves subject to this procedure are: the median, ulnar, cranial cutaneous antebrachial, lateral cutaneous antebrachial, caudal cutaneous antebrachial, medial cutaneous antebrachial, deep br. of radial N., dorsal br. of ulnar N., lateral and medial palmar Nn., deep palmar br. of ulnar N., lateral and medial palmar metacarpal Nn., lateral and medial palmar digital Nn. and palmar br. of palmar digital N. Original illustrations accompany the text.
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AN ALTERNATIVE TO PROBLEM-BASED LEARNING. Collister, J.P., A.E. Vetter, E.M. Gallant, and A.F. Weber. Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108.
The challenges faced by educators are becoming increasing more demanding, especially those encountered by faculty of professional schools such as veterinary colleges. The rapid increase in knowledge of the biological sciences has resulted in students entering veterinary schools with both a heightened awareness and expectation of their professional education. With such a magnification of currently known information, it is critical, now more than ever, that veterinary students are taught the fundamental principles and mechanisms of the basic sciences. In this way, they are given both the knowledge base and the broad deductive skills necessary for successful clinical practice or pursuit of one of the many other aspects of veterinary medicine. At the same time, it is necessary for students to understand the relevance and importance of what is being taught and to begin their exposure to clinical medicine.
The approach of problem associated learning (PAL) is meant to draw from the ideals of both traditional teaching and problem based learning, while avoiding some of the disadvantages of either format alone. Freshman veterinary students possess only a fraction of the necessary skills and knowledge to fully comprehend most complete clinical cases. Alternatively, in this example, weekly clinical scenarios are presented throughout freshman gross anatomy which focus on the current important anatomical structures or principles being taught. By augmenting the traditional lecture and laboratory in this manner, the student not only learns the necessary fundamental skills, but also gains a heightened awareness of the clinical relevance of their basic science education.
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ANATOMY OF REPTILES. Evans, Howard E., Department of Veterinary Anatomy, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-6401.
(No Text Available)
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VETERINARY EDUCATION IN NEPAL VETERINARY ANATOMY. Abbott, Louise C., Department of Veterinary Anatomy & Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4458.
(No Text Available)
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VETERINARY ANATOMISTS FROM AROUND THE WORLD - PAST AND PRESENT. Evans, Howard E., Department of Veterinary Anatomy, College of Veterinary Medicine, Cornell University, Ithaca, NY 148536401.
(No Text Available)
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CUTANEOUS INNERVATION OF THE HEAD OF THE CAT. Bailey, C.S., and R.L. Kitchell, Departments of Surgery and Radiology and Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616-8732.
The total cutaneous area (CA), overlap zone, and autonomous zone of the cutaneous nerves supplying the feline head were determined using electrophysiological techniques. Each of 20 mature cats placed under general anesthesia; vital signs were monitored continuously. The hair of the head was clipped and landmarks placed on the skin. The nerves were isolated and recorded from as previously described. At the end of each experiment, the cat was euthanatized with an overdose of intravenous sodium pentobarbital. Identification of the nerves was verified by gross dissection. The cutaneous nerves innervating the feline head were branches of the trigeminal, facial, and 2nd cervical nerves. Trigeminal nerve: The CA of the ophthalmic branch included the upper eyelid and rostral lower lid and extended somewhat rostrally and caudally to the dorsal midline. The CA of the maxillary branch extended from the dorsal midline at the medial base of the pinna ventrally to the zygomatic arch, including the lateral canthus of the eye, then rostrally to include the lower eyelid, upper lip and nose to the dorsal midline. The CA of mandibular branch innervated the mandibular skin rostrally from the caudal border of the mandibular bone and ventrally to the midline. Facial nerve: This nerve supplied the skin of the concave surface of the pinna. Cervical nerve 2: This nerve supplied the skin of the caudal portion of the head from the dorsal midline to the ventral midline, including the convex surface and the margins of the concave surface of the pinna, and the skin overlying the ramus and caudal body of the mandible and the larynx. The CA also included the cranial portion of the neck to the level of the transverse process of the C2 vertebra. In general, overlap among nerves was substantial and autonomous zones were small.
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IN VIVO EXPRESSION OF GRPs IN THE MOUSE DURING ORGANOGENESIS. Barnes, J.A., and I.W. Smoak, Department of Anatomy, Physiological Sciences, and Radiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606.
Glucose regulated proteins (GRPs) and heat shock proteins (HSPs) are members of the "stress protein" family. HSPs have been well characterized during development and many have found a tissue-specific pattern of HSP expression in embryonic tissues. To date, little is known about the normal expression of GRPs in embryos. GRP synthesis increases in response to hypoglycemia, a condition which is known to induce cardiac dysmorphogenesis in rodent embryos in vitro. This study investigates the distribution pattern and cardiac levels of GRP94 in mouse embryos in vivo during the period of organogenesis. Distribution and cardiac levels of GRP94 were determined in mouse embryos in vivo on gestational days (gd) 8.5, 9.5, 10.5, 11.5, 12.5, and 1 3.5 (plug=gd 0.5). To determine the distribution pattern of GRP94, embryos were fixed in 4% paraformaldehyde, processed for immunohistochemistry and immunostained using a rat monoclonal antibody specific for GRP94. To determine cardiac levels of GRP94 during organogenesis, embryonic heart tissues were isolated, subjected to 1-D SDS-PAGE and immunoprobed with a specific GRP94 antibody. Results of immunohistochemical studies demonstrate that mouse embryos undergoing organogenesis express GRP94 protein predominately within developing heart, neural tube, and surface ectoderm tissues. Western blot analysis of embryonic mouse hearts indicate a constant level of GRP94 expression throughout cardiac development. Considering the tissue specific pattern of GRP94 expression, further investigation into the role GRPs play during development of these tissues is warranted.
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NEURONAL EXPRESSION OF CALBINDIN-D28K AND SUBSTANCE P IN THE INTESTINE OF VERTEBRATES; A COMPARATIVE STUDY IN TWO SPECIES. Inpanbutr, N., S. Tangkawattana, and J. Masty, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210-1092.
Calbindin-D28k, a 28 kd vitamin D-dependent calcium binding protein first isolated in chicken intestine, was subsequently found in several tissues of other species including neural tissues. Calbindin-D28k was localized in discrete regions of the central nervous system. In this study, an immunohistochemical investigation was undertaken to compare the localization of calbindin-D28k and substance P in the gastrointestinal tract of two dissimilar species, the chicken and the horse. Preliminary findings indicate that both calbindin-D28k and substance P are found in the neural tissues of the digestive tract with some minor variations. In both species, substance P and calbindin-D28k are localized in nerve fibers present in the submucosa and the circular muscle layer. There were no substance P-positive fibers seen associated with the musculature of the outer longitudinal layer of the digestive tube of both species. However, calbindin-D28k was observed in the nerve fibers of the outer longitudinal muscular layer in the chicken. Positive fibers were also identified within the myenteric ganglia. The most striking difference was observed in the submucosal ganglia. The perikarya of submucosal neurons were commonly positive for substance P in the equine species; there was no positive identification of calbindin-D28k in any submucosal neurons in the chicken. The functional significance of calbindin-D28k in these neural elements is not evident from this initial study, but it does indicate that calbindin-D28k and substance P are located in comparable layers of the gastrointestinal tract in these two species.
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MODULATION OF CALBINDIN-D9K EXPRESSION IN THE COW UTERUS. Tangkawattana, S, J.D. Reiswig, and N. Inpanbutr, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210-1092.
The calbindins, calbindin-D9k and calbindin-D28k, were first implicated as mediators of vitamin D-dependent transcellular calcium transport in the intestine of the rat and chicken, respectively. Our previous studies have localized calbindin-D9k within the uterus of the cow. Immunostainable calbindin was seen in the uterine glandular epithelium of all specimens. Reactivity for the protein was also seen in the luminal epithelium of some samples. Positive cells contained immunostainable calbindin-D9k within the nucleus and cytosol. RIA and dot blot hybridization revealed the levels of both the protein and it's mRNA were three fold higher during the luteal phase than during the follicular phase. These results indicated that calbindin-D9k may be involved in uterine glandular function during the luteal phase. In this study, the in vitro model was used to study the effects of calcium manipulation on the expression of calbindin-D9k in non-pregnant cow uterus. Explant uterine endometrium was incubated with calcium ionophores, Thapsigargin and Quin 2 in culture media. Expression of calbindin-D9k was determined by using a dot blot immunobinding assay, immunohistochemistry, and a quantitative immunofluorescence technique (ACAS 470 Interactive Laser CytometerTM). The preliminary data suggested that the increment of intracellular calcium by Thapsigargin increased calbindin-D9k expression in the cow endometrium in vitro.
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MOVABLE JOINTS ON SKELETAL PREPARATIONS ENHANCE UNDERSTANDING OF ORTHOPEDIC BIOMECHANICS. Janick, L.M., T.K. Rowles, and R.W. Henry. College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996-4500.
To an anatomy laboratory, the skeleton is an invaluable resource. It can be used to demonstrate a wide variety of concepts inclusive of muscle attachments, nerve and vessel passages (foramina), and overall morphology. However, functional morphology is difficult to teach with current skeletal preparations because they are static. This study has therefore developed a technique for the construction of an articulated skeleton with movable joints. The joints are assembled through the fabrication of hinges made out of metal (1/2" x 3" x 1/16"). The articulating surfaces of the joint are slotted at their pivot points. The slot for the convex surface is made to fit the width and thickness of the hinge. The depth of the slot should be made sufficient to allow the hinge to be anchored by a pin (inserted into a hole which has been drilled perpendicularly through the bone and the hinge). The slot in the concave surface is made to the thickness of the hinge but the width is extended in both directions to allow movement. This end of the hinge is also secured by a pin inserted through the bone and hinge. The vertebrae were assembled into four sections: cervical, thoracic, lumbar with sacrum, and caudal. Alignment of the vertebrae was accomplished by a 3/8" aluminum rod inserted through the vertebral foramen. At both ends of the thoracic section and the adjacent ends of the lumbar and cervical sections, the aluminum rod was threaded and steel plates were attached. Four adjustable screws were used to join the plates of adjacent sections to allow controlled movement of the spinal column. These enhancements provide a more holistic approach to functional morphology. Students and clinicians both will benefit through a better understanding of movement and balance, as well as biomechanics.
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EFFECT OF ORAL INSULIN AND EPIDERMAL GROWTH FACTOR ON LUMINAL ESCHERICHIA COLI IN THE NEONATAL PORCINE SMALL INTESTINE. Lamar, C.H. and A.M. Saeed. Department of Basic Medical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
Epidermal growth factor (EGF) and insulin are components of mammalian colostrum and milk. Suckled, 12 to 14-hour-old pigs were fed milk replacer supplemented with EGF (0.42 mg/day) or insulin (85 microUnits/ml). On day 4, control and supplemented pigs received orally one billion E. coli 987P. Twenty-four hours later, the pigs were euthanatized with an intravenous overdose of sodium pentobarbital. Tissue samples were collected from the distal jejunum and proximal ileum for bacteriological and morphological evaluations. A 2-3 fold reduction in E. coli 987P was observed in the insulin-supplemented pigs, as compared to the EGF-supplemented and control pigs. Morphologically, lectin histo-chemistry, using Ulex europaeus agglutinin I, did not demonstrate any changes to the mucosal surface of the distal small intestine. Ultrastructurally, measurement of the microvilli in all pigs did not identify any significant differences. Damage to mitochondria and microvilli was observed in control pigs and two pigs supplemented with insulin.
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USE OF SYMMETRIC AXIS TRANSFORMATION FOR DIAGNOSING ANGULAR LIMB DEFORMITY IN FOALS. Rumph, Paul F., Department of Anatomy and Histology, College of Veterinary Medicine, Auburn University, AL 36849-5518.
Angular limb deformity in foals includes several common conditions in which the conformation of an extremity is abnormal. If untreated, this potentially serious orthopedic problem can threaten the future athletic performance of affected foals. Diagnosis of angular limb deformity in foals has been based on subjective evaluation of conformation and radiographic assessment of affected limbs. Common to many of the methods employed to describe angulation was a straight line representing the axis of the bones but scant guidance has been provided for drawing such axes. Symmetric axis transformation (also called line skeleton analysis, medial axis, symax, and symmetrical axis) is a technique that has been found to be particularly well-suited for analysis of forms that lack discrete points along their borders. Essentially, symmetric axis transformation reduces a complex biological form to a simple line skeleton that reflects its shape. The antebrachium, carpus and metacarpus of nine Thoroughbred foals of either sex were radiographed on one film in craniocaudal projection within one week of: birth, 1 month of age, 3 months of age, and 6 months of age. From the radiographs, symmetric axes were derived. The axis of the metacarpus was found to be straight; whereas, the axis of the radius was found to be an arc. The angulation between maximal radial chords (the chords connecting the ends of the arc) and metacarpal axes were measured. The carpal angulation between the metacarpal axis and the maximal chord of the radial arc was 8 degrees or less. Differences between sides of the body and among age groups were not significant. Symmetric axis transformation was useful in interpreting forelimb bone axes and measuring the angles between them.
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ROD BODY IN THE AGED PONY HEART. Tangkawattana, P., S. Tangkawattana, T. Nakayama, and M. Yamaguchi, Muscle Biology Lab, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210-1092.
Rod body formation is associated with various kinds of muscle disorders, naturally and/or artificially induced atrophies in skeletal muscle or concentric hypertrophy of cardiac muscle. Aged cardiac muscle obtained from an 33-year-old pony was examined by transmission electron microscope to see if rod body is also developed in the pony heart. The various parts of left and right ventricles fixed with 2.5% glutaraldehyde, and postfixed with 1% osmic acid, were processed for conventional electron microscopy. We have found single and groups of rod bodies ( hypertrophic Z-line and non-sarcomere rod body) in the left ventricle. The rod body appears to be a typical crystalline-like structure which should contain actin backbone filament and a-actinin as described previously (Tangkawattana, 1994, Yamaguchi et al., 1983) . The random orientation of rod bodies, misalignment of myofibrils, accumulation of abundant glycogen granules, and appearance of abnormal intercalated discs characterize typical muscle disorders observed in other animals including human.
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ABSENCE OF PSEUDOPOD FORMATION IN ACTIVATED ELEPHANT PLATELETS. Gentry, Patricia A., Lynn A. Cheryk, and Shigeto Yamashiro, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada NlG 2Wl.
It has been shown that platelets from Asian elephants, like bovine platelets, are relatively unresponsive to ADP, are highly responsive to PAF stimulation and that aggregation is not dependent on thromboxane production (Gentry et al. Comp. Biochem. Physiol. 96:131, 1990). To determine whether there were also similar ultrastructural features between bovine and elephant platelets, platelet rich plasma was prepared from citrated whole blood and treated with an equal volume of 0.1% glutaraldehyde. The mixture was centrifuged and the pellet covered with 3.0% glutaraldehyde, stained with 2% tannic acid and post fixed with osmium tetroxide. The samples were dehydrated with an ascending series of ethanol and embedded in Epon. Ultrathin sections of the pellets were stained with uranyl acetate and lead citrate and examined in a JEOL 100S transmission electron microscope. Like the bovine platelet, platelets from Asian elephants lack a well developed open canalicular system and one of the principle morphological features is the presence of numerous large granules. The examination of aggregates of elephant platelets, formed following the addition of nanomolar concentrations of PAF, showed that the aggregates contained platelets that had generally maintained their intact morphology with no evidence of pseudopod formation. The inner zone of the platelet aggregates contained intact cells in which granules were still clearly visible while the outer zone was made up of platelets that for the most part retained their discoid shape, were slightly flattened and were devoid of granules. The similarity of the morphologic and biochemical characteristics between Asian elephant and bovine platelets and the dissimilarity between these cells and human platelets suggest that more than one type of mammalian platelet may exist.
Supported by the Natural Sciences and Engineering Research Council of Canada and the Ontario Ministry of Agriculture, Food and Rural Affairs.
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ANTLERS: A CROSS-CURRICULAR CAL PROJECT. Davies, A.S. and P.R. Wilson, Departments of Physiology and Anatomy, and Veterinary Clinical Studies, Massey University, Palmerston North, New Zealand.
"Antlers" was created as a computer assisted learning project for a number of diverse reasons. The subject is difficult to present in a practical way by other means, especially to link it to the clinical situation in live animals. The histology and physiology of antler growth is not described in any textbook available to our students. The topic is being presented at two distinct levels of the curriculum and it seems desirable to integrate the concepts into one teaching package. In New Zealand, velvet harvesting not only has considerable economic significance, but also animal welfare implications. The program is constructed in HyperCard, based on a series of cards that illustrate the antler cycle from the hard antler stage through casting, growth of vascular cartilage and progressive ossification, death of the bone, rubbing of the velvet and the reformation of hard antler. A movie animation relates these events to the season of the year and the circulating testosterone levels. Other diagrams show the physiology of antler growth, sites for local anesthesia and the appearance of commercial velvet. At early and ossifying stages, the histology of tissues that grow as fast as any tumor is shown at appropriate levels of magnification. The program will be expanded to include angiographic images to show the vascular arrangement within antlers, and X-ray computed tomography to show the remarkable fusion of living pedicle with dead bone. We are using over 20 programs in teaching anatomy, embryology and histology. For several of these, illustrations and ideas from other veterinary schools have been most helpful. All these programs are available for sharing with anyone interested.
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ANATOMY AND PHYSIOLOGY OF SOMATOSENSORY RECEPTORS. Kitchell, R.L., D. Magliano, and R. Hayes. Department of Anatomy, Physiology and Cell Biology, and the California Assisted Learning Facility, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616-8732.
This is a multimedia presentation prepared using a Macintosh II computer and Supercard 1.7. The presentation is a stand alone requiring a Mac II computer with 5 MG. RAM. The objectives of the presentation are to accompany a lecture/laboratory course of neuroscience for veterinary students. It is designed to be an adjunct to a lecture on somatosensory receptors - which is often neglected because of time restraints. It should add a new dimension to the usual course in neuroscience because it contains actual recordings from somatosensory receptors in animals done by the senior author. The presentation begins by classifying and illustrating the general morphology of sensory receptors and their relationship to the primary afferent fiber. This is followed by illustrations of the development of generator potentials and how they initiate nerve impulses in the primary afferent fibers. The role of the generator potentials in very rapidly adapting, rapidly adapting, and slowly adapting receptors is illustrated. Simulated and actual responses of these types of receptors are illustrated. This is followed by an illustration of how sensory receptor activity is recorded from primary afferent fibers. The next part of the presentation concerns mechanoreceptor activity related to how and which mechanoreceptors signal position, direction and velocity of mechanical stimuli. Each function is illustrated by graphics of the receptor, simulated and videotaped responses from different receptors from single units isolated from nerves of deeply anesthetized dogs. The addition of activity of nociceptors and thermal receptors is in progress. This presentation is the initial segment of a presentation in preparation of the Ascending Pathways of Animals which is expected to be completed by summer 1996.
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