Microscopic and ultrastructural studies of necrotizing hepatopancreatitis in Pacific white shrimp (Penaeus vannamei) cultured in Texas.

Granulomatous hepatopancreatitis of unknown etiology has been considered an important disease of Texas shrimp mariculture since 1985. Samples of Pacific white shrimp (Penaeus vannamei) were collected during 1986, 1987, and 1990 from three farms and an experimental mariculture facility with histories of production loss and increased mortality rates. Histologic and ultrastructural examination of shrimp from the four sites demonstrated two morphologically distinct, Gram-negative, double-enveloped, intracytoplasmic bacteria in necrotic hepatopancreatic epithelium. The more numerous small, pleomorphic rod as well as the helical organism are both taxonomically unclassifiable. The helical organism lacked ultrastructural characteristics of previously described helical or spiral bacteria. The relationship between the two organisms is unknown, but the pleomorphic rod is thought to play a major role in the disease. The role of a bacterial agent(s) in subsequent disease episodes is suggested by the observation that the use of oxytetracycline-medicated feed resulted in increased production and survival. Hepatopancreatic tubular epithelial necrosis and shrimp mortality correlated directly with the extent of infection by the small pleomorphic rod. Individual discrete bacteria were identified microscopically by Steiner and Steiner's method. Three major developmental stages of the disease were characterized based on the extent and number of hepatopancreatic tubular epithelial cells containing bacteria, the degree of tubular interstitial inflammation, and the extent and chronicity of tubular necrosis. Additional studies are needed to clarify the roles of the different bacteria identified and the potential role of environmental factors on the disease process.

Observations on the anatomy of the stomach and duodenum of the bowhead whale, Balaena mysticetus.

Gastric and cranial duodenal structure of the bowhead whale (Balaena mysticetus) was examined grossly and microscopically. The stomach was arranged in a series of four compartments. The first chamber, or forestomach, was a large nonglandular sac lined by a keratinized stratified squamous epithelium. It was followed by the fundic chamber, a large, somewhat globular and entirely glandular compartment. At the entrance of the fundic chamber, a narrow cardiac gland region could be defined. The remaining mucosa of the chamber contained the proper gastric glands. A narrow, tubular connecting channel, the third distinct gastric division, was lined by mucous glands and joined the fundic chamber with the final stomach compartment, or pyloric chamber. This fourth chamber was also tubular and lined by mucous glands but was of a diameter considerably larger than the connecting channel. The stomach terminated at the pyloric sphincter which consisted of a well-developed band of circular smooth-muscle bundles effecting a division between the pyloric chamber and small intestine. The small intestine began with the duodenal ampulla, a dilated sac considerably smaller than the fundic chamber of the stomach. The mucosa of this sac contained mucous glands throughout. The ampulla led without a separating sphincter into the duodenum proper which continued the intestine in a much more narrow tubular fashion. The mucosal lining of the duodenum was composed of villi and intestinal crypts. Although their occurrence varied among whales, enteroendocrine cells were identified within the mucous glands of the cardiac region, connecting channel, pyloric chamber, and cranial duodenum. The hepatopancreatic duct entered the wall of the duodenum shortly after the termination of the duodenal ampulla and continued intramurally along the intestine before finally joining the duodenal lumen.

Electrographic recording from bovine vomeronasal capsule under spontaneous and stimulated conditions.

The vomeronasal organ ( VNO ) is an accessory olfactory system which in many vertebrates seems to be involved in reproductive behavior, particularly in permitting males to detect estrus in conspecific females. We postulated that EEG-like field potentials could be recorded from the VNO because the organ has a sensory epithelium that can discharge in response to odorants, and because VNO receptor cells are structurally similar to cells in the olfactory mucosa that produce field potentials (the "electro- olfactogram "). We examined this postulate in male cattle by surgically implanting recording/perfusion cannulae into the ducts leading to each VNO . Both bipolar (between VNOs ) and reference recording revealed continuous spontaneous voltage fluctuations that were similar to an EEG, except that amplitudes were larger and frequencies slower. Simultaneous recording of the EEG and VNO , using the same nasal reference electrode revealed that neither signal was "contaminated" by voltages from the other. Perfusions of one VNO with whole urine, urine condensate, or aqueous reconstituted urine extracts, whether from females in estrus or in anestrus, produced massive transient electrical responses from both VNOs . Perfusion with penicillin or local anesthetics caused more sustained large electrical responses from both VNOs , except that activity became quiescent about 15 min after local anesthesia. These results suggest that it is feasible to use direct recording of VNO responses to stimulation to investigate the behavioral physiology of the VNO .(ABSTRACT TRUNCATED AT 250 WORDS)

Cemental annulation as an age criterion in forensic dentistry.

Intact teeth were obtained from three cadavers of known age 56, 67, and 76 years, respectively. Cross-sections 100-150 micrometers thick were taken from the roots using a diamond saw. Individual sections were stained, mounted on glass slides, and photographed on a light microscope. The usual number of years for the eruption of any particular tooth were added to the annulation count to determine the estimated age for that cadaver.

Supplemental feeding of marmoset (Callithrix jacchus) triplets.

In a colony of marmosets (Callithrix jacchus), all fifteen infants from five sets of triplet births were successfully reared with their parents. Two supplemental feedings were given each infant daily. As an alternative to hand-rearing or foster rearing, the supplemental feeding method eliminated the time-consuming process of hand caring for an infant on a 24-hour per day basis.

Structures of the bovine vomeronasal complex and its relationships to the palate: tongue manipulation.

The rostral part of the bovine vomeronasal complex was examined to determine its relation structures of the palate which are compressed by the tongue during investigative sexual behavior. The rostral vomeronasal cartilage (VNC) is C-shaped and contains the incisive duct (ID). The hilus of the cartilage is directed medially, approximately 0.5 cm dorsal to the palate. Just caudal to the origin of the vomeronasal duct, the VCN lies approximately 1 cm above the palate with a ventrally oriented hilus containing the ID. Further caudally, the hilus is directed laterally, toward the nasal cavity. Palatal mucosa occupies the intervomeronasal, cartilaginous area below the nasal septum and caudal to the incisive papilla. This mucosa and the ID appear to be compressed by the bull's everted tongue, forcing fluid samples into the vomeronasal system.

Tongue manipulation of the palate assists estrous detection in the bovine.

To understand the mechanisms for introducing urine or vaginal secretions into the vomeronasal organ, we used 16 mm cinematography and a freeze frame/slow motion technique to analyze the mouth and tongue movements of Brahman bulls while they examined the vulvas of restrained, estrogen-primed cows. Prior to flehmen, the mouth slowly opened, the curled tip of the tongue compressed the hard palate and the body of the tongue protruded from the mouth. The tongue maintained this form and moved forward. Once the tip of the tongue reached the incisive papilla, the body of the tongue retracted and the tip of the tongue relaxed. This tongue compression stroke (TCS) of the hard palate occurred 2 to 6 times, lasting 1 4 to 1 2 sec/stroke. Pressure changes in the vomeronasal organ are assumed to occur during and following TCSs, resulting in aspiration of any liquid in the incisive pit into the incisive and vomeronasal ducts. Such aspiration probably does not occur during flehmen because the tongue is relaxed and on the floor of the mouth.

Cemented annulation as an age criterion in the common marmoset (Callithrix jacchus).

Teeth from 18 marmosets, seven months to 5.8 years of age, were studied histologically. A minimum of one dark and one light band comprised one cemental annulation. Age was estimated by counting the number of annulations and adding four months to premolar and eight months to canine teeth for tooth development. Cemental annulations were most consistent near the gingival border on the labial aspect of the tooth. The method will be valuable in estimating the ages of marmosets and other nonhuman primates.

Ascending projections of the dorsal column in a garter snake (Thamnophis siritalis): a degeneration study.

Ascending axons in the dorsal column of garter snakes were examined following hemisection of the spinal cord at segment levels 2, 3, 4, 11, 13, and 31. After postoperative survival periods of 11 to 28 days, sections of the spinal cord and brain were processed with a silver method to demonstrate degenerated axons and preterminals. The study demonstrated that most ascending degenerated axons are located in the outer half of the dorsal column. The somatotopic pattern of ascending fibers is evident, whereby dorsomedial fibers are primarily of caudal origin and the more dorsolateral axons are from rostral cord segments. Rostral to segment 31, all spinal segments appear to project to a strip of dorsal column adjacent to the dorsal median septum. From the septum, axons descend to terminate somatotopically on cells of the nucleus of Bischoff located caudal to the obex of the medulla. Dorsal column degeneration ascends to the level of the dorsal column nuclei, where most fibers terminate. Degeneration from caudal cord segments terminates on caudo-medial cells of the dorsal column nuclei, while rostral cord segments project to rostro-lateral cells. The dorsal column nuclei consist of an expanded lateral part between tractus descendens trigemini and the vago-solitary complex, and a contiguous, thin medial lamina of cells dorsal and medial to the vagal nuclei. The somatotopic pattern of degeneration in the dorsal column nuclei, probably of dorsal root origin, follows the mammalian organization, which suggests that the garter snake has primitive nuclei gracilis and cuneatus. Other terminal sites of degenerating fibers, although probably of spinal gray origin, are nucleus commissura infima, nucleus descendens vestibuli, and area postrema.

Observations on a colony of cotton eared marmosets Callithrix jacchus with some plans for future expansion.

The current and proposed colony design and management are described. In an effort to increase the neonatal survival of marmosets, an outdoor-indoor housing arrangement is planned.