Abstracts of the 1996 Meeting of the American Association of Veterinary Anantomists



Titles

Return to AAVA Home Page


CHARACTERIZATION OF CEREBELLAR DEVELOPMENT IN THE LEANER MUTANT MOUSE. Abbott, L.C., and F.C. Lau, Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 778434458.


INTERACTION OF Escherichia coli LIPOPOLYSACCHARIDE (E. coli LPS) WITH SHEEP PULMONARY INTRAVASCULAR MACROPHAGES: ULTRASTRUCTURAL IMMUNOCYTOCHEMICAL STUDY. Singh, B. and O.S. Atwal, Dept. Biomedical Sciences, University of Guelph, Guelph, ON Canada N1G 2W1.


CANINE ANATOMY - AN INTERACTIVE APPROACH. Adams, D.R., L.D. Evans, and L.L. Gerken, Department of Veterinary Anatomy, Iowa State University, College of Veterinary Medicine, Ames, Iowa 50011.


EFFECTS OF HYPOTHYROIDISM ON FETAL AND ADULT LEYDIG CELL POPULATIONS IN THE NEONATAL RAT TESTIS. Mendis-Handagama, S.M.L.C., R.L. Haupt, K.R. Teunissen van Manan, Department of Animal Science, College of Veterinary Medicine, The University of Tennessee, Knoxville. TN 37996.


PRELIMINARY REPORT ON THE BLOOD SUPPLY OF THE REPRODUCTIVE TRACT OF THE FEMALE EMU Dromaius novaehollandiae. Cope, L.A., R.W. Henry, J. Blackford, and T. K. Rowles, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996.


UNEXPECTED VALVE IN AN UMBILICAL CORD ARTERY OF AN EQUINE RETAINED PLACENTA ENCOUNTERED DURING INJECTION OF COLLAGENASE: PRACTICAL IMPLICATION FOR UMBILICAL CORD INJECTIONS. Haffner, J.C. and H. Eiler. Department of Large Animal Clinical Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996.


PREPARATION AND EVALUATION OF PLASTINATED GASTROINTESTINAL SPECIMENS FOR USE IN ENDOSCOPIC TRAINING. Janick, L.M., R.W. Henry, and R.C. Denovo, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996.


GROSS MORPHOLOGY OF THE INTESTINAL TRACT OF THE TILAPIA Oreochromis niloticus. Smith, B.J., S.A. Smith, and B. Tengjaroenkul. VA-MD Regional College of Veterinary Medicine, Blacksburg, VA 24061 0442.


ORGANIZATION OF CORTICOTROPIN RELEASING NEURONS AND CATECHOLAMINERGIC NEURONS IN THE BRAIN OF Equus caballus. Littlefield-Chabaud, M. A. and P. A. Melrose, Department of Anatomy and Cell Biology, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8408.


PORCINE GROSS ANATOMY. Jaeger, L.A., N.H. McArthur, C.C. Farnsworth, H. Haughn, and C.H. Lamar, Department of Veterinary Anatomy & Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4458 and Department of Basic Medical Sciences, School of Veterinary Medicine, West Lafayette, IN, 47907.


A LITTLE HISTORY OF VETERINARY ANATOMY. Evans, Howard E. Department of Veterinary Anatomy, College of Veterinary Medicine, Cornell University, Ithaca, NY 148536401.


BRAINSTEM NUCLEI - 3D REPRESENTATION, PART I, DOG. McClure, R.C. and G.M. Constantinescu, College of Veterinary Medicine, University of Missouri - Columbia, Columbia, MO 65211.


AN INTERACTIVE HISTOLOGY COURSE FOR CD-ROM AND WORLD WIDE WEB ACCESS. Caceci, Thomas, Virginia-Maryland Regional College of Veterinary Medicine, Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0442.


IMMUNOLOCALIZATION OF CELLULAR RETINOL BINDING PROTEIN IN THE RAT TESTIS AND QUANTIFICATION OF SERTOLI CELLS AND INTERSTITIAL CELL TYPES FROM BIRTH TO ADULT AGE. Ariyaratne, H.B.S., S.M.L.C. Mendis-Handagama, and J.D. Godkin, Department of Animal Science, The University of Tennessee, Knoxville, TN 37996.


ULTRASTRUCTURAL STUDY OF PULMONARY INTRAVASCULAR MACROPHAGES OF LENTIVIRUS-INFECTED SHEEP. Singh B. and A. de la Concha-Bermejillo, Texas A&M University Research Center, 7887 N. Hwy 87, San Angelo, TX 76901.


THE EXPRESSION OF CHOLECYSTOKININ BINDING SITES IN THE DEVELOPING MAMMALIAN BRAIN: A COMPARATIVE STUDY. Kuehl-Kovarik, M.C. and C.D. Jacobson. Dept. of Veterinary Anatomy and Neuroscience Program, Iowa State University, Ames, IA 50011.


HISTOLOGY OF THE INTESTINAL TRACT OF THE TILAPIA Oreochromis niloticus. Smith, B.J. and S.A. Smith. VA-MD Regional College of Veterinary Medicine, Blacksburg, VA.


THE POWER OF NON-AQUEOUS FIXATION. Sims, D.E. and M.M. Horne, Department of Anatomy & Physiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PEI, Canada ClA 4P3.


ONTOGENY OF ANDROGEN RECEPTOR-LIKE IMMUNOREACTIVITY IN THE REPRODUCTIVE TRACT OF MALE BRAZILIAN RAT Monodelphis domestica. Sonea1, I.M., G.S. Prins2, and C.D. Jacobson1. Dept. of Veterinary Anatomy1, College of Veterinary Medicine, Iowa State University, Ames, IA 50011-6513 and Dept. of Urology2, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612-7316.


OBSERVATIONS ON THE ULTRASTRUCTURE OF UTERINE GLANDS OF MARES INFUSED WITH POVIDONE IODINE SOLUTION. Al-Bagdadi, F.1, G. Richardson2, B. Eilts3, L. Olsen4, D. McCoy3, W. Braun5, L. Archbald6, D. Thompson7, and C. Titkemeyer1, 1Department of Veterinary Anatomy and Cell Biology, 3Department of Veterinary Clinical Sciences, 7Department of Animal Science, Louisiana State University, Baton Rouge, LA 70803, 2Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PEI, Canada, ClA 4P3, 4Foxland Farm, P.O. Box 117, Keen, KY 40339, 5Department of Veterinary Clinical Science, College of Veterinary Medicine, Columbus, MO 65211, 6Veterinary Teaching Hospital, College of Veterinary Medicine, Gainesville, FL 623100125.


AMELIORATION OF CARBON TETRACHLORIDE HEPATOTOXICITY WITH GADLINIUM CHLORIDE IN RATS. Gareau, P.J., L.A. Reinke, J.Z. Chen, E.G. Janzen, and S. Yamashiro, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON NlG 2W1.


UNDERSTANDING EQUINE INGUINAL RINGS MADE EASY VIA A FABRICATED MODEL. Henry, R.W., C. L. Henry, and L. M. Janick. Department of Animal Science, College of Veterinary Medicine The University of Tennessee, Knoxville, TN 37996.


MOVABLE SKELETAL PREPARATIONS OF THE JOINTS OF THE EQUINE FORELIMB. Nguyen, A.Q. and P.T. Purinton, Department of Anatomy and Radiology, College of Veterinary Medicine, University of Georgia, Athens. GA 30602-7382.


EFFECT OF EXAMINATION OF A CROSS SECTION OF THE CANINE HEAD ON STUDENTS' ABILITY TO VISUALIZE ANATOMY IN THREE DIMENSIONS. Provo, J., C. Lamar, E. Hinsman, and T. Newby, Department of Basic Medical Sciences and Department of Curriculum and Instruction, Purdue University, West Lafayette, IN 47907.


THE BIOLOGY OF THE LUCKE TUMOR SYSTEM OF Rana pipens. Williams, C.S.1, J.W. Williams2, S. Torrence2, A. Gamill2, N. Marshall2, D. Sterling2, D. Carlson3, and R.G. McKinnell4: Departments of Anatomy1 and Biology2, Tuskegee University, Tuskegee, AL 36088; Department of Biology3, Augustana College, Sioux Falls, SD 57197; Department of Genetics and Cell Biology4, University of Minnesota, St. Paul, MN 55108.


ABSTRACTS

Return to AAVA Home Page


CHARACTERIZATION OF CEREBELLAR DEVELOPMENT IN THE LEANER MUTANT MOUSE. Abbott, L.C., and F.C. Lau, Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 778434458.

The leaner mouse is a cerebellar mutant mouse carrying an autosomal recessive mutation on the 8th chromosome which results in severe ataxia starting at postnatal day 10 (P10) to P12. Previous work has revealed that cerebellar granule cells (gcs) begin to die at P10 in these mice and Purkinje cells (PCs) begin to die at approximately P25-P30. The cell loss is not random. Rather, when adult leaner cerebella are examined histologically, it is apparent that the PCs are lost in a series of rostrocaudal bands such that a band of PCs survive and then an adjacent band of PCs will die. Gc loss appears to follow a similar pattern in that many gcs are missing in the same rostrocaudal bands that show Pc loss. However, some gcs remain in all bands, resulting in an apparent difference in cell density between bands. We have also observed in the adult leaner cerebellum that multiple Pc dendritic spines (Pcdss) synapse with some of the parallel fiber (pf) varicosities, which is an abnormal finding. We are investigating possible developmental changes that might be occurring in the leaner cerebellum which could result in the abnormalities observed in adults. We examined paraffin sections of leaner cerebella at P10, P20, P30, and P40 for evidence of programmed cell death (PCs) in the gcs and PCs. Terminal deoxynucleotidyl transferase enzyme was used to attach digoxigenin-dUTP to DNA 3'0H ends. Fragmented DNA (a positive sign for PCD) through a peroxidase-antiperoxidase (PAP) immunocytochemistry reaction to the digoxigenin-labeled DNA was detected in some gcs. The number of positive gcs in leaner cerebella was significantly higher than age-matched controls at P20. No evidence for PCD has been observed in leaner PCs. Standard EM procedures were used to examine Pc/pf synapses. The abnormal synaptic pattern between some Pcdss and pf varicosities observed in adult leaner cerebella also was observed at P20, suggesting that the abnormal synaptic pattern is not the result of synaptic remodelling occurring as a result of the ataxic condition. Earlier ages will be examined to determine whether further observations are consistent with already reported.

INTERACTION OF Escherichia coli LIPOPOLYSACCHARIDE (E. coli LPS) WITH SHEEP PULMONARY INTRAVASCULAR MACROPHAGES: ULTRASTRUCTURAL IMMUNOCYTOCHEMICAL STUDY. Singh, B. and O.S. Atwal, Dept. Biomedical Sciences, University of Guelph, Guelph, ON Canada N1G 2W1.

Pulmonary intravascular macrophages (PIMs) of domestic animal species contain novel surface and intracellular globules, and are believed to play a significant role in the genesis of pulmonary pathology. This study was conducted to investigate responses of sheep PIMs to E. coli LPS. Sheep (N=5) were treated with E. coli LPS (0128:B12) one µgm/ kg body weight iv and euthanized at 3, 8, 10, 30 and 180 min (n= 1) after the treatment. One sheep injected with saline solution served as the control. Lungs were fixed in situ with 2% paraformaldehyde and 2.5% glutaraldehyde for 30 minutes. Lung tissues were collected and immersion-fixed for 15 minutes or three hours and processed for TEM. Ultrathin sections were incubated with 1 % ovalbumin for 30 minutes to block nonspecific binding and floated face down on a drop of a polyclonal anti-E. coli LPS antibody (0128:B12; 1:20) for 30 minutes. Primary antibody binding was detected by exposing the sections to gold conjugated secondary anti-IgG antibody (1:50) for 30 minutes. Sections from the control and treated sheep incubated with the primary polyclonal anti-E. coli LPS antibody and without a primary antibody respectively served as the negative controls. The PIMs from control sheep exhibited the globules on their plasma membrane as well as in the endosomes. Surface as well as endosomal globules and nuclear matrix of the PIMs were labeled with gold particles at 8 minutes post-treatment. Negative control specimens were devoid of any labeling. Simultaneous signs of structural damage to plasma membrane, endosomes and nuclear envelope, loss of the coat and multiple endosomes were noticed. Secretory organelles such as Golgi complex and associated transport vesicles became conspicuous from 8-30 minutes of the treatment. The results suggest a novel interaction of E. coli LPS with the coat globules and their probable role in its rapid endocytosis by the PIMs and their consequent secretory activation.

CANINE ANATOMY - AN INTERACTIVE APPROACH. Adams, D.R., L.D. Evans, and L.L. Gerken, Department of Veterinary Anatomy, Iowa State University, College of Veterinary Medicine, Ames, Iowa 50011.

This gross anatomy program is authored in Authorware Professional 3.0 on the PC platform. It consists of more than 25 files with a combined size of >25 MB. Images (640 X 480 pixels at 256 colors) are displayed on a monitor set at 1024 X 768 pixels. Although still not complete, the program contains 1,300 images distributed as follows: Directional Terminology (8), Body Regions (8), Musculoskeletal (672), Respiratory (112), Digestive (153), Urinary (15), Reproductive (33), Cardiovascular (118), Lymphatic (29), and Peripheral Nervous (122). Some 17 multiple-choice quizzes in the program permit student selection and self testing. Each quiz contains randomization of both questions and response options for each question. Feedback is provided for each response option selected. Program usage by, and quiz results for, student users are written to a file for use by the instructor. Now, during final stages of program development, the authors welcome contribution from anatomists at other institutions (chapter authorship or revision, suggestions and criticism, and/or image contribution).

EFFECTS OF HYPOTHYROIDISM ON FETAL AND ADULT LEYDIG CELL POPULATIONS IN THE NEONATAL RAT TESTIS. Mendis-Handagama, S.M.L.C., R.L. Haupt, K.R. Teunissen van Manan, Department of Animal Science, College of Veterinary Medicine, The University of Tennessee, Knoxville. TN 37996.

We have shown previously that transient neonatal hypothyroidism in rats causes Leydig cell hyperplasia, hypotrophy and reduced steroidogenic capacity at 135 days of age. In the present study we investigated the effects of the same treatment on fetal and adult Leydig cell populations in the neonatal rat testes. Transient neonatal hypothyroidism was induced in one day old Sprague Dawley rats by feeding the lactating mothers with 0.1% (w/v) propyl thiouracil (PTU) in drinking water from the day of parturition until the pups were weaned at 21 days of age. Testes of rat pups (1,7,14 and 21 days old; 5 rats per group) of these PTU-treated mothers were fixed by immersion (days 1 and 7) and by whole body perfusion (days 14 and 21), processed and embedded in Epon Araldite for microscopy and morphometry. Similarly, testes were prepared from rat pups of control mothers (no PTU in drinking water) to use as controls. One micron sections of testis tissue were stained with methylene blue and used for microscopy and morphometry. Volume density of fetal and adult Leydig cells (defined as the volume of Leydig cells per unit volume of the testis) was determined by the point counting methods. Numerical density of fetal and adult Leydig cells (defined as the number of cells per unit volume of testis) in these rats was determined by the dissector method. The number of Leydig cells per testis was determined by multiplying the numerical density of Leydig cells by the fresh testis volume. The average volume of a Leydig cell was determined by dividing the volume density by the numerical density of Leydig cells. Qualitatively, fetal Leydig cells in testes of 1, 7 and 14 day old control rats were observed as large circular or polygonal profiles containing circular-shaped nuclei with abundant euchromatin. Lipid droplets were plenty in their cytoplasm and most of these regions appeared as empty spaces due to the extraction of lipid during tissue processing. Profiles of fetal Leydig cells at day 21 in control rats were smaller but the other morphological characteristics were similar to those at 1, 7 and 14 days. In PTU rats, fetal Leydig cell profiles appeared similar in size from birth to 21 days of age. They were similar in size and morphological characteristics to the fetal Leydig cell profiles in control rats from 1-14 days of age. However, in PTU rats many fetal Leydig cells contained irregular nuclear profiles in them. Leydig cell profiles of the adult generation in control rats were first detected at day 14, but they were more in number at day 21 compared to day 14. They were smaller in size than the fetal Leydig cell profiles from 1-14 days, but approximated the size of fetal Leydig cell profiles at day 21. A distinct cytoplasmic characteristic in the adult Leydig cell generation was that there were little or no lipid droplets in them. In PTU rats, profiles of adult Leydig cell generation was not observed. Morphometric studies revealed that fetal Leydig cell number per testis in control and PTU rats were not different at all ages studied, and did not change in number from birth to 21 days of age. The average volume of a fetal Leydig cell in control and PTU rats were similar at days 1, 7 and 14 days. However, at day 21, average volume of fetal Leydig cell in control rats was 50% smaller than those at 1-14 days in control rats and 1-21 days in PTU rats. Adult Leydig cell number per testis in control rats showed a significant increase at day 21 compared to day 14, however, as stated before, they were not observed in PTU rats at any neonatal age studied. These results demonstrate that neonatal hypothyroidism causes an inhibition of fetal Leydig cell atrophy at day 21 of age and suppression of the emergence of adult Leydig cell generation in the neonatal rat testis. Based on these observations we suggest that thyroid hormones perform an important role in establishing the adult Leydig cell population in the rat testis. (Supported by NSF IBN 94-09288)

PRELIMINARY REPORT ON THE BLOOD SUPPLY OF THE REPRODUCTIVE TRACT OF THE FEMALE EMU Dromaius novaehollandiae. Cope, L.A., R.W. Henry, J. Blackford, and T. K. Rowles, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996.

The arterial supply to the left ovary of the female emu was accomplished by the ovarian artery, a branch of the ovario-oviductal artery. The ovario-oviductal artery branched from the left cranial renal artery after it diverged from the left side of the descending aorta and traveled under the ventral surface of the left kidney. Six vessels supplied the oviduct of the emu. These arteries were branches of the left cranial renal, left pubic, left middle renal and left pudendal arteries. From cranial to caudal, the first artery of the oviduct was the cranial oviductal artery, a branch of the ovario-oviductal artery. It supplied the dorsal surface of the infundibulum and magnum. The second artery was the accessory cranial oviductal artery which had three main branches. 1) The first branch anastomosed with a branch of the cranial oviductal artery, 2) The second branch anastomosed with a branch of the middle oviductal artery on the dorsal surface of the oviduct, and 3) The third branch anastomosed with the ventral marginal artery. The third artery, the middle oviductal artery, supplied the middle of the oviduct. This artery was a branch from the left middle renal artery. The fourth artery was the caudal oviductal artery which supplied the caudal extent of the uterus and proximal part of the vagina. This artery originated from a branch of the left internal iliac, cranial to its bifurcation into the lateral caudal and pudendal arteries. The final arteries of the oviduct were the medial and lateral vaginal arteries which were branches of the left pudendal artery and supplied the medial and lateral sides and the dorsal surface of the vagina. The ovary was drained by an ovarian vein which was formed by anastomoses of the follicular veins. The ovarian vein emptied into the left adrenal vein which joined the left side of the caudal vena cava. The venous return of the oviduct was accomplished by the cranial oviductal vein, accessory cranial oviductal vein, middle oviductal vein, caudal oviductal vein and medial and lateral vaginal veins which were satellites of the arteries and drained into the caudal vena cava.

UNEXPECTED VALVE IN AN UMBILICAL CORD ARTERY OF AN EQUINE RETAINED PLACENTA ENCOUNTERED DURING INJECTION OF COLLAGENASE: PRACTICAL IMPLICATION FOR UMBILICAL CORD INJECTIONS. Haffner, J.C. and H. Eiler. Department of Large Animal Clinical Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996.

Retained placentas have been successfully treated in the cow by umbilical cord injections of collagenase. This has led to the study of the application of this technique in mares. While attempting to infuse the umbilical cord arteries of a retained placenta in two mares, significant resistance to fluid flow in the normograde direction was encountered. This encouraged us to review the anatomy of umbilical cord vessels for the purpose of clinical infusion of collagenase via umbilical cord arteries. Two experiments were conducted. First, a placenta that presented flow obstruction during umbilical cord artery infusion was dissected. Second, following normal delivery, placentas were collected, and these were dissected after fluid flow study. Supportive histological study was conducted in selected umbilical vessels. The umbilical cord arteries of the placenta that had been retained contained valves which impeded normograde fluid flow. The valves were approximately 10 cm from the fetal end of the umbilical cord arteries, and there were no other valves in the vessels. Arteries from other placentas studied contained no valves. It was concluded that umbilical cord arteries may contain valves that oppose normograde flow of perfusate. The physiologic implication of this is unknown. From a practical point of view if difficulty to perfuse an umbilical cord artery is encountered, the catheter should be reinserted about 10 cm closer to the placenta or above the valve.

PREPARATION AND EVALUATION OF PLASTINATED GASTROINTESTINAL SPECIMENS FOR USE IN ENDOSCOPIC TRAINING. Janick, L.M., R.W. Henry, and R.C. Denovo, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996.

Endoscopy is an important diagnostic and therapeutic tool in human and veterinary medicine. Although live patients are useful as an effective and necessary technique in endoscopic training, their procurement and preparation are expensive. Use of live animals is also inefficient and time-consuming, especially for the "first-time" endoscopist with no endoscope manipulation experience. As an alternative method of instruction, plastinated gastrointestinal tracts have been prepared for use in teaching both endoscopic technique and anatomy. However, having a lifelike specimen that looks anatomically correct is not sufficient. These specimens must be engineered to insure that they: 1) have most or all of the ingesta flushed free, 2) retain orifices that are large enough to accommodate the GI endoscope (9.6 mm), and 3) maintain a proper degree of dilation. When properly prepared these plastinated specimens can provide an accurate model for the trainee to learn the manipulative skills of guiding the endoscope through the gastrointestinal tract. The important anatomic features of the upper gastrointestinal tract [cardiac ostium (ostium cardiacum), gastric fundus (fundus ventriculi), gastric body (corpus ventriculi), gastric folds (plicae gastricae), the cardiac notch (incisura angularis), the pyloric antrum (antrum pyloricum), and pylorus (ostium pyloricum)] are readily identified. The endoscope can be easily passed into the duodenum and advanced distally. Basic manipulations such as retroflex examination of the gastric cardia (pars cardiaca) and cardiac sphincter intubation of the pylorus, foreign body removal, and biopsy techniques can be done using these specimens.

GROSS MORPHOLOGY OF THE INTESTINAL TRACT OF THE TILAPIA Oreochromis niloticus. Smith, B.J., S.A. Smith, and B. Tengjaroenkul. VA-MD Regional College of Veterinary Medicine, Blacksburg, VA 24061 0442.

The intestinal tract of the tilapia Oreochromis niloticus follows a rather complex course that includes several loops. From cranial to caudal, the principal areas have been designated as the hepatic loop, the proximal major coil, the gastric loop, the distal major coil, and the terminal segment. Except for the terminal segment, each of these principal areas is subdivided into readily recognizable regions. On leaving the stomach and progressing from cranial to caudal, these segments are: proximal limb of the hepatic loop, distal limb of the hepatic loop, first centripetal loop (of the proximal major coil), first centrifugal loop (of the proximal major coil), proximal limb of the gastric loop, distal limb of the gastric loop, second centripetal coil (of the distal major coil), second centrifugal coil (of the distal major coil), and the terminal segment. The major coils are arranged in a cone-shaped mass, in manner such that their four individual loops are nested each internal to the previous one. Thus, the first centripetal loop (i.e. of the proximal major coil) is external, and the second centrifugal loop (i.e. of the distal major coil) is most internal. Few external features distinguish one region of the gut tube from another. However, in general, the external diameter of the gut loops decreases slightly from cranial to caudal. Internally, the intestinal mucosa is characterized by folds. In the cranial regions of the intestine, the folds are arranged in a chevron pattern and are oriented parallel with the long axis of the gut tube. However, the pattern becomes irregular in the region of the gastric loop, and in the second centripetal and remaining loops, the orientation of the folds lies transverse to the long axis of the gut tube.

ORGANIZATION OF CORTICOTROPIN RELEASING NEURONS AND CATECHOLAMINERGIC NEURONS IN THE BRAIN OF Equus caballus. Littlefield-Chabaud, M. A. and P. A. Melrose, Department of Anatomy and Cell Biology, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8408.

Corticotropin-releasing hormone (CRH) and various catecholaminergic cell groups act together to coordinate stress-dependent activation of the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS). Work performed on various species has characterized neuronal pathways involved in the stress-dependent activation of the ANS. The stress-dependent activation of catecholaminergic cell groups by CRH suggests that CRH drives the ANS response to stress. The purpose of this project was to characterize the distribution of CRH and catecholaminergic cell groups and fibers in the equine central nervous system (CNS) in order to determine if the organization of CRH and catecholaminergic neurons suggest that CRH controls the ANS response to stress in the equine species. In the first experiment, brains from three mixed breed ponies were sectioned from the obex to the hypothalamus. Sections were stained immunocytochemically with antibodies against CRH and rate-limiting enzymes for catecholamine synthesis. Results from this study indicated that CRH and catecholaminergic neurons in the equine species are organized for coordination of ANS activity by CRH neurons. In the second experiment, messenger RNA (mRNA) was collected from regions of the CNS and the adrenal gland as a secondary means of characterizing the distribution of CRH neurons. Results from this experiment indicated that CRH is widely distributed throughout the CNS. Combined results of these experiments support the hypothesis that CRH controls both the HPA and ANS response to stress in the equine species.

PORCINE GROSS ANATOMY. Jaeger, L.A., N.H. McArthur, C.C. Farnsworth, H. Haughn, and C.H. Lamar, Department of Veterinary Anatomy & Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4458 and Department of Basic Medical Sciences, School of Veterinary Medicine, West Lafayette, IN, 47907.

A self-directed program was developed to assist students studying porcine gross anatomy. The program was created using Authorware and a Macintosh computer. The program is designed for use with laboratory activities, as well as post-laboratory review and study. Porcine anatomy is studied from a regional perspective, and covers major and clinically important features of the porcine head and neck, thorax, abdomen, pelvis and reproductive systems, distal limbs, and skeleton. The consensus of initial responses from the first-year students who utilized this program was that it was helpful, but should not be used to replace a "hands-on" laboratory experience. Responses were divided regarding whether or not this computerized format was an adequate replacement for a lecture on this topic. This program may also be useful to students in latter years of the veterinary curriculum who wish to review porcine anatomy in preparation for animal or necropsy rotations, as well as for board examination. The program will be available for distribution on CD-ROM to interested veterinary colleges. Any comments or suggestions for final revision of this program are welcome. Supported by a grant from the Center for Teaching Excellence and the College of Veterinary Medicine, Texas A&M University.

A LITTLE HISTORY OF VETERINARY ANATOMY. Evans, Howard E. Department of Veterinary Anatomy, College of Veterinary Medicine, Cornell University, Ithaca, NY 148536401.

(No Text)

BRAINSTEM NUCLEI - 3D REPRESENTATION, PART I, DOG. McClure, R.C. and G.M. Constantinescu, College of Veterinary Medicine, University of Missouri - Columbia, Columbia, MO 65211.

This is a report on preliminary efforts to develop "phantom" depictions of the brainstem nuclei in the dog, which can be computerized for student use. Visualization of the structures and their interrelationships is important to learning and understanding, particularly in anatomy. Illustrations of cross sections from the Stereotaxis Atlas of the Dog Brain, Lim, Liu, and Moffitt, (1960) were used as a basic guide for the development of a model of the brainstem showing the location and relationship of the motor nuclei. This information was scanned (digitized) for importation into the computer.

AN INTERACTIVE HISTOLOGY COURSE FOR CD-ROM AND WORLD WIDE WEB ACCESS. Caceci, Thomas, Virginia-Maryland Regional College of Veterinary Medicine, Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0442.

The level of computer literacy among incoming veterinary students is increasing rapidly, as is the availability and affordability of computers with high-resolution graphics capabilities. At the same time, there has been a shift in student preferences for learning tools that are visually oriented and not paper-based. To keep pace with this trend, most colleges have begun the transition from paper handouts and notes to electronic ones. "VM8054, Veterinary Histology" is an example. It is a complete course in electronic format: students are provided with all administrative course material, course policies, and extensive exercises in electronic format. The exercises include the text of previous paper version, plus they incorporate over 600 color images taken from the student slide set and instructor demonstration slides. These are matched to extended captions that are linked to the images. The material is accessed either from a CD-ROM (on a stand-alone basis) or via the World Wide Web server in our College. Students with modem-equipped computers can log onto the server and study exercises, complete with images, at home or from the College library; or they can obtain a copy of the CD and work independently. The software was written in HTML language, and is intended to be viewed with NETSCAPE or other WWW browsers. Images were photographed on slide film, digitized with a scanner, and edited with graphics software in standard .JPG format. For students who demand a paper printout, the CD includes copies in WORD 6.0, and also in Adobe ACROBAT. Not only does electronic teaching material suit the preferences of modern students, it saves the College a great deal of money. Prior to this year, VM8054 alone was costing about $1000 per year in copying fees. By providing access to the software via the WWW, the cost to the College of making much more information available is effectively nil.

IMMUNOLOCALIZATION OF CELLULAR RETINOL BINDING PROTEIN IN THE RAT TESTIS AND QUANTIFICATION OF SERTOLI CELLS AND INTERSTITIAL CELL TYPES FROM BIRTH TO ADULT AGE. Ariyaratne, H.B.S., S.M.L.C. Mendis-Handagama, and J.D. Godkin, Department of Animal Science, The University of Tennessee, Knoxville, TN 37996.

In mammals retinol deficiency causes infertility. In the testis, spermatogenesis is known to be dependent on adequate supply of vitamin A, which is taken up as retinol from blood by the Sertoli cells. Sertoli cells are rich in cellular retinol binding protein (CRBP) which has an important role in controlling the uptake of retinol. In Leydig cells, retinol has been shown to increase testosterone production, however the mechanism is still unknown. Retinol is known to cause proliferation of peroxisomes in many tissues and peroxisomes in Leydig cells have been shown to have a role in their steroidogenic function. Therefore, we designed the present study to examine the distribution of CRBP in rat testis cells from birth to adult age to gather preliminary data to design further experiments to investigate the role of retinol and CRBP in Leydig cell steroidogenesis. We also quantified Sertoli cells and different cell types in the testis interstitium. Sprague Dawley rats of 1, 7, 14, 21, 40, 60 and 90 days (3 rats per group) were euthanized by carbon dioxide inhalation, testis were removed, fixed in Bouin's fixative, processed and embedded in paraffin. Five micron sections were made from each paraffin embedded testis and CBRBP was immunolocalized using anti-bovine CRBP antibody. Tissue sections were viewed and cells in the interstitium, namely, the Leydig cells, intermediate cells (cells which were morphologically in between Leydig cells and mesenchymal cells), mesenchymal cells, fibroblasts, endothelial cells, pericytes, peritubular myoid cells and macrophages, and the Sertoli cells were quantified. The absolute numbers of cells in the testis interstitium were calculated by two steps. First, the ratio of each cell type to Leydig cells was determined. Second, this ratio was multiplied by the Leydig cell number per testis at each age. The latter value was obtained using one micron sections of perfusion-fixed and epon-araldite embedded testicular tissue via the dissector method. The morphometric results revealed that there was a gradual decrease of the number ratio of Leydig cells to all other cell types tested with advancing age. However, the absolute number of all these cell types per testis was increased concomitantly up to 90 days of age. The immunocytochemical studies revealed the following. The Sertoli cells and germ cells stained positively for CRBP in all ages studied, however, from birth to 21 days of age the staining was lighter than in the other age groups. The Leydig cells showed a positive reaction in all age groups studied, and they were the only interstitial cell type that showed positive reaction from birth to 21 days of age. On days 40,60 and 90 pale positive reaction was observed for CRBP in all other interstitial cells tested except the macrophages, which were not positive for CRBP at all age groups studied. These results demonstrate that CRBP is present in the Leydig cells from birth (Leydig cells of the fetal generation) to adult age (mature Leydig cells of the adult generation) and from late prepubertal (i.e. day 40, has newly formed Leydig cells of adult generation) period, CRBP concentration in Leydig cells is greater than those at neonatal ages studied (days 1-21). This increase in CRBP concentration in Leydig cells coincides with the time that Leydig cells undergo maturational changes which includes cell hypertrophy and hyperplasia of organelle content to establish the adult Leydig cell population in the sexually mature animal. Therefore, it is possible that retinol induces proliferation of peroxisomes during this maturational period and that CRBP concentration in Leydig cells is increased after 40 days of age to increase its uptake into Leydig cells. This concept warrants further investigation. (Supported by NSF IBN 94-09288).

ULTRASTRUCTURAL STUDY OF PULMONARY INTRAVASCULAR MACROPHAGES OF LENTIVIRUS-INFECTED SHEEP. Singh B. and A. de la Concha-Bermejillo, Texas A&M University Research Center, 7887 N. Hwy 87, San Angelo, TX 76901.

Ovine lentivirus (OvLV), the putative cause of lymphoid interstitial pneumonia (LIP), resembles the human immunodeficiency virus. The OvLV DNA integrates in the genome of monocytic cells and requires their differentiation into macrophages for its replication. Although alveolar macrophages are attributed a central role in the pathogenesis of LIP, yet the precise interplay of different pulmonary cell types in this disease is not known. This study was performed to investigate the structural features of a recently identified phagocyte, pulmonary intravascular macrophage (PIM), in OvLV infection. Four sheep were infected intratracheally with 1x106 TCID50 °f OvLV-34 strain while two sheep received equal volume of the culture medium and were used as the control. All the infected sheep became seropositive between 14-28 days post-infection as indicated by the agar gel immunodiffusion test. The sheep were euthanized at 10 weeks post-infection and lungs were fixed in situ with 2% paraformaldehyde and 2.5% glutaraldehyde for 30 minutes. Lung tissue pieces were immersed in the same fixative for three hours, osmicated, treated with 0.5% tannic acid for 30 minutes and processed for TEM. The PIMs from control sheep were attached to the capillary endothelium and showed globules on their plasma membrane and in the endosomes. Some PIMs of the infected sheep appeared to lack a full complement of the surface coat globules although intracellular globules seemed unaltered. These PIMs contained occasional small aggregates of virion-like particles, and displayed expanded Golgi complexes, secretory vesicles, microtubules, centrioles, elaborate profiles of rough endoplasmic reticulum and nuclear interchromatin granules. These results suggest possible slow replication of OvLV in the PIMs and their enhanced biosynthetic activation in the infected sheep. Studies for the immunolocalization of viral proteins in the PIMs of infected sheep are currently underway.

THE EXPRESSION OF CHOLECYSTOKININ BINDING SITES IN THE DEVELOPING MAMMALIAN BRAIN: A COMPARATIVE STUDY. Kuehl-Kovarik, M.C. and C.D. Jacobson. Dept. of Veterinary Anatomy and Neuroscience Program, Iowa State University, Ames, IA 50011.

Neurogenesis in the Brazilian opossum, Monodelphis domestica, is a predominantly postnatal process, unlike central nervous system (CNS) formation in placental mammals. Therefore, Brazilian opossum newborns cannot regulate homeostasis at the forebrain level, although control centers for food intake are located in the forebrain of the adult mammal. Thus, the Brazilian opossum provides an excellent mammalian model to study CNS adaptations for neonatal existence, and in addition, may provide information on neural pathways that are specific for the survival of extremely altricial marsupial neonates. Because the forebrain of the Brazilian opossum is still forming at birth, we predict that hindbrain nuclei may be involved in the regulation of nutrient intake. A significant peptide involved in food intake regulation is cholecystokinin (CCK). These studies focused on the expression of CCK binding sites in neonatal rat and opossum brainstem nuclei that could potentially be involved in the regulation of nutrient intake. We found that CCK binding sites are transiently expressed in the FMN of both the neonatal opossum and the developing rat. As the FMN controls facial musculature, it is intimately involved in suckling behavior in neonates. The transient expression of binding sites in this region suggests that cholecystokinin may be regulating nutrient intake at the brainstem level in mammalian neonates. Supported by grants from the Whitehall Foundation and the National Science Foundation.

HISTOLOGY OF THE INTESTINAL TRACT OF THE TILAPIA Oreochromis niloticus. Smith, B.J. and S.A. Smith. VA-MD Regional College of Veterinary Medicine, Blacksburg, VA.

The overall structure of the intestine of Oreochromis niloticus is similar to that of most vertebrate species in consisting of the four classical concentric tunics: mucosa, submucosa, muscularis, and serosa. In turn, each of the tunics largely fits the generalized model of structure typical of most vertebrates. The mucosa is comprised of a simple columnar epithelium interspersed with goblet cells, and a thin lamina propria that blends with the submucosa. The submucosa is generally composed of loose connective tissue containing occasional leukocytes, eosinophilic granular cells, and small blood vessels. The muscularis is comprised of inner circular and outer longitudinal muscle layers, with prominent intermyenteric plexuses. The adventitia consists of a thin connective tissue layer, and can carry larger blood vessels. Like many other species of fish, this tilapia possesses few distinguishing histological characteristics in these tunics among the various topographic regions of the intestine. Still, a general pattern of progression of some histological features can be observed progressing cranially to caudally, though the exact level at which they are expressed is variable. In general, the mucosa of the more cranial parts of the intestine possess well-developed villi with moderate numbers of goblet cells. The villi decrease in prominence in the relatively caudal regions of the intestine, but increase again in the most terminal segment. The submucosa becomes attenuated in the later segments, containing fewer cellular components and more open space. The muscularis generally progresses from having a thicker outer than inner layer in the more cranial regions, to an approximately 1: 1 ratio of thickness of the two layers in the caudal-most intestinal area.

THE POWER OF NON-AQUEOUS FIXATION. Sims, D.E. and M.M. Horne, Department of Anatomy & Physiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PEI, Canada ClA 4P3.

Fixation methods for light and electron microscopy have barely changed over the decades. Constant problems, which teachers and researchers have been forced to tolerate or compensate for, include adjusting for tissue pH and osmolarity, and an inability to preserve most carbohydrate structures. An alternative protocol is offered to circumvent these limitations. Non-aqueous fixation (also called phase-transition fixation) is not a new concept, but has been improved by development of superior coolants for electronics manufacturers. When FC-72TM, a product from the 3-M Co. Ltd, is used as solvent, and 1 % w/ v osmium tetroxide is dissolved as a fixing agent, the opportunity exists to conduct fixations without significant challenges to pH or osmolarity. Glycoprotein secretions are preserved on fish skin, in mammalian airways, within blood vessels, and surrounding bacteria. FC-72TM is a non-toxic perfluorocarbon, and has a high affinity for dissolved oxygen, enabling preflushing that doesn't create tissue hypoxia. After initial non-aqueous fixation and a rinse in pure fluorocarbon to remove any residual osmium, processing for light microscopy can proceed by cutting tissue to size and placing in conventional formalin solution, then processing in a routine manner. For transmission electron microscopy, initial fixation and rinse can be followed by two dehydration rinses in 100% ethanol, then routine solvent/ embediment steps. For scanning electron microscopy, fixation can be followed by dehydration in ethanol, than any of the methods available. Biofilms, mucous coats, and glycocalyxes have previously been difficult to retain. With nonaqueous fixation methods, they can be preserved in a manner that compares well to freeze fixation, but without the artifact of crystal formation.

ONTOGENY OF ANDROGEN RECEPTOR-LIKE IMMUNOREACTIVITY IN THE REPRODUCTIVE TRACT OF MALE BRAZILIAN RAT Monodelphis domestica. Sonea1, I.M., G.S. Prins2, and C.D. Jacobson1. Dept. of Veterinary Anatomy1, College of Veterinary Medicine, Iowa State University, Ames, IA 50011-6513 and Dept. of Urology2, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612-7316.

To detect when reproductive tissues become sensitive to the effects of endogenous androgens, the appearance and distribution of androgen receptor-like immunoreactivity (AR-LI) was studied in the reproductive tract of the developing and adult gray short-tailed Brazilian opossum (Monodelphis domestica), using a rabbit polyclonal androgen receptor antibody (PG2 1) . Androgen receptor-like immunoreactivity was first detected on the fifth day of postnatal age, in the mesenchymal tissues of the ductus deferens, gubernaculum testis, and prostatic urethra, and in the mesenchymal tissue of the perineal, inguinal and scrotal areas. Androgen receptor-like immunoreactivity was first seen in the interstitial cells of the epididymis at 45 days of age; the testes developed AR-LI at 60 days of age. The first epithelial cells of prostatic glands to contain AR-LI were seen at 80 days of age; much of the prostatic epithelium was androgen receptor-like immunoreactive in the adult. The presence of AR-LI during development correlated well with the known androgen-dependence of the differentiation of most reproductive organs. The early appearance of AR-LI in the scrotum suggests that scrotal development in this marsupial is at least partially androgen dependent. Supported by grants from the College of Veterinary Medicine of Iowa State University (IMS), the Whitehall Foundation, and the National Science Foundation (CDJ), and the National Institutes of Health (GSP).

OBSERVATIONS ON THE ULTRASTRUCTURE OF UTERINE GLANDS OF MARES INFUSED WITH POVIDONE IODINE SOLUTION. Al-Bagdadi, F.1, G. Richardson2, B. Eilts3, L. Olsen4, D. McCoy3, W. Braun5, L. Archbald6, D. Thompson7, and C. Titkemeyer1, 1Department of Veterinary Anatomy and Cell Biology, 3Department of Veterinary Clinical Sciences, 7Department of Animal Science, Louisiana State University, Baton Rouge, LA 70803, 2Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PEI, Canada, ClA 4P3, 4Foxland Farm, P.O. Box 117, Keen, KY 40339, 5Department of Veterinary Clinical Science, College of Veterinary Medicine, Columbus, MO 65211, 6Veterinary Teaching Hospital, College of Veterinary Medicine, Gainesville, FL 623100125.

The uterine glands play an important part in nourishing the fetus in the epitheliochorial type of placenta in the mare. It is a concern to veterinarians that intrauterine infusion of medications for treatment may produce pathological changes in the mare's endometrium that interfere with fertility. This study describes the uterine gland cells and the uterine response to povidone iodine infusion in mares. Veterinarians have used various medications to treat endometritis in mares. Five light horse mares of breeding age were used in this study; they were infused with 1% povidone iodine solution. The number of mast cells in the 30 day post povidone iodine infused (PPIM) mares were higher than the 15 days post povidone iodine infused mares. Some of the mast cells of the 30 day PPIM were ruptured releasing massive quantities of histamine and serotonin. The mast cells seemed to be migrating towards the uterine glands and were morphologically different from the basal cells. The fine structural morphology of the basal cells indicate that they do not resemble mast cells as has been suggested. This study indicates that mast cells, leukocytes and basal cells are three different types of cells. This preliminary study indicates that the pathological effects of the intrauterine infusions of povidone iodine, are more severe after a second infusion, 15 days after the first.

AMELIORATION OF CARBON TETRACHLORIDE HEPATOTOXICITY WITH GADLINIUM CHLORIDE IN RATS. Gareau, P.J., L.A. Reinke, J.Z. Chen, E.G. Janzen, and S. Yamashiro, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON NlG 2W1.

In our previous electron microscopic studies on carbon tetrachloride (CCl4) induced hepatotoxicity in rats, we observed a paucity of phagosomes in Kupffer cells (KC) of gadlinium chloride (GdCl3) treated rats, which exhibited no hepatocytic injury with CCl4. Suspension of inert carbon particles (India ink) was used to visualize the KC phagocytic activity in rats with or without GdCl3 prior to the CCl4 treatment. Rats received CCl4 (320 µl/kg i.p.) or CCl4 and GdCl3 (l0 mg/ kg, i.v.) or GdCl3 alone. In the separate study, the comparable treatment groups received India ink (0.5 ml of 1% suspension per animal) immediately after the respective treatment. Hepatotoxicity was evaluated 24 hours after CCl4 administration by light microscopy, and serum levels of alanine aminotransferase (ALT) as well as magnetic resonance imaging (MRI). Rats injected with GdCl3 exhibited no KC phagocytic activity of India ink with or without CCl4 treatment, suggesting the KC inhibitory activity of GdCl3. Treatment with CCl4 resulted in elevated ALT activity in the serum, periacinar necrosis in histopathology and a greatly increased signal intensity within the liver MR images. In rats pretreated with GdCl3 the severity of CCl4induced liver injury was dramatically reduced. GdCl3 reduced the elevation in ALT activity by approximately 75%. Lower ALT activities and histopathology indicated protection from liver damage by GdCl3.

UNDERSTANDING EQUINE INGUINAL RINGS MADE EASY VIA A FABRICATED MODEL. Henry, R.W., C. L. Henry, and L. M. Janick. Department of Animal Science, College of Veterinary Medicine The University of Tennessee, Knoxville, TN 37996.

The inguinal rings and canals, as well as, the vaginal ring and process are often conceptually difficult for veterinary students to understand. To help students understand the inguinal area, a model was fabricated using cloth (netting and batiste) and a prepared osteology specimen of the equine pelvis and femurs. The bone preparation was prepared using typical maceration and degreasing technologies, assembled and mounted on a wooden base. The internal and external abdominal oblique muscles were tailored from cloth and the superficial and deep inguinal rings were formed. The courses of the genitofemoral nerve and branches of the pudendoepigastric vessels: caudal epigastric, external pudendal and caudal superficial epigastric vessels were indicated using ribbon.

MOVABLE SKELETAL PREPARATIONS OF THE JOINTS OF THE EQUINE FORELIMB. Nguyen, A.Q. and P.T. Purinton, Department of Anatomy and Radiology, College of Veterinary Medicine, University of Georgia, Athens. GA 30602-7382.

Movable joints are valuable teaching aids for demonstrating limb position and movement in Veterinary Gross Anatomy. Illustrated here are articulated specimens of equine shoulder, elbow, carpus and digit produced at the University of Georgia, College of Veterinary Medicine. The object was to prepare skeletal specimens that would mimic the normal direction, articulation, and range of movements. Several specimens are on display to illustrate these valuable teaching aids.

EFFECT OF EXAMINATION OF A CROSS SECTION OF THE CANINE HEAD ON STUDENTS' ABILITY TO VISUALIZE ANATOMY IN THREE DIMENSIONS. Provo, J., C. Lamar, E. Hinsman, and T. Newby, Department of Basic Medical Sciences and Department of Curriculum and Instruction, Purdue University, West Lafayette, IN 47907.

A cross-section of the canine head was used to enhance the understanding of first year veterinary students of anatomy of the head in three dimensions. In addition to the dissection of the head done by control students, experimental groups in two successive classes (n=124) identified structures visible in the cross-section. A paper-and-pencil test was designed to measure student's ability to visualize anatomy in three dimensions by requiring 1) prediction of structures visible in a cross-section; 2) correct placement of structures within an outline of the cross-section; and 3) correct placement of 8 structures within two perpendicular views of the head. Validation procedures for this test instrument demonstrated content validity, strong inter-rater reliability, and moderate test-retest reliability. Questions requiring visualization of anatomical structures were also included on one live animal examination. Multivariate analysis of covariance revealed statistically significant effects on the dependent variables of performance on prior course examinations and quizzes, and a statistically significant three-way interaction effect between group membership, prior examination and prior quiz performance. A separate analysis was performed using data from the second class (n=62) in this study, when spatial ability of the student was also used as a covariant. Results show a statistically significant effect of spatial ability, and statistically significant two way interactions between group membership and prior quiz performance. Qualitative methods, including surveys completed by all students, and interviews with 15 students randomly selected from a pool of volunteers, were used to collect data regarding students' self-perceptions of ability to visualize anatomy in three-dimensions and opinions about the value of the instructional methods used for this study.

THE BIOLOGY OF THE LUCKE TUMOR SYSTEM OF Rana pipens. Williams, C.S.1, J.W. Williams2, S. Torrence2, A. Gamill2, N. Marshall2, D. Sterling2, D. Carlson3, and R.G. McKinnell4: Departments of Anatomy1 and Biology2, Tuskegee University, Tuskegee, AL 36088; Department of Biology3, Augustana College, Sioux Falls, SD 57197; Department of Genetics and Cell Biology4, University of Minnesota, St. Paul, MN 55108.

The Lucke renal carcinoma of Rana pipiens, a herpesvirus induced neoplasm of kidney-precursor cells, displays temperature dependent dissemination and development. Intact viral particles, necessary for dissemination of the tumor to other individuals, are produced only below 10°C. Invasion (metastasis) occurs only at temperatures above 21°C both in vivo and in vitro. These characteristics make this tumor an excellent model in which to study the role of chromosomes in expression of neoplastic and metastatic phenotypes. Chromosome spreads obtained from a naturally occurring primary tumor contained a normal 2N=26, number of chromosomes and active NORs, 2/2N, 10q. A putative triploid experimentally viral-induced primary tumor was also found to be euploid, 3N-39, with 3 active NORs, 10q. However, tumor allografts maintained in anterior eye chamber cultures for more than 7 years were highly aneuploid. Leukocytes from a frog with a naturally occurring massive primary tumor and extensive metastatic sites exhibited an essentially normal diploid, 2N=26, chromosomal complement. The primary renal tumor and several metastatic sites (liver, lung, body wall) were histologically similar. Tumor cells were epithelial, arranged around tubular lumens, reminiscent of kidney morphology. The primary tumor and metastatic lesions showed extensive leukocytic infiltration. (Supported by NIH/ MBRS Grant 5S06GM08091 and NIH/RCMI Grant G12RR03059, Tuskegee University and CTR-USA Grant 2675, University of Minnesota)

Return to AAVA Home Page