A functional comparison of the hyolingual complex in pygmy and dwarf sperm whales (Kogia breviceps and K. sima), and bottlenose dolphins (Tursiops truncatus)

The function of the hyolingual complex in three odontocete species was investigated to compare adaptations of divergent feeding strategies, suction and ram feeding. Pygmy and dwarf sperm whales, members of the genus Kogia (or kogiids), are known to be strong suction feeders. We tested the hypotheses that kogiids would have a larger, more robust hyolingual complex, and that hyolingual muscles would have a greater maximum theoretical muscle tension compared with ram-based feeders such as bottlenose dolphins (Tursiops truncatus). A robustness index and surface area was calculated for bony hyoid elements in kogiids and bottlenose dolphins. The anatomy, muscle architecture, pinnation, two-dimensional angle of attachment and maximum theoretical muscle tension were measured in each hyolingual muscle. A functional model incorporating vector analyses of hyolingual musculature was created for kogiids and bottlenose dolphins to assess differences in function of their hyolingual complexes. Kogiid hyoid surface areas were significantly greater (P = 0.01) than in bottlenose dolphins. Most maximum theoretical muscle tensions of hyolingual complexes were not significantly different within or between species. The data suggest that associated orofacial and tongue morphology, particularly the relationship of hyoid shape and tongue retractor muscles, greatly influences suction capability in odontocetes. Kogiids demonstrated adaptations that occlude lateral gape, including a novel vertical ridge on each side of the mandible, and a shortened mandible that is capable of a large gape, and gape angle. These adaptations presumably assist in maintaining negative intraoral pressure generated by the depression and retraction of the relatively short and wide kogiid tongue. The tongues of kogiids should be capable of generating greater intraoral volume changes compared with the long, narrow tongue of bottlenose dolphins.     

Comparative morphology of the cloacal scent gland in snakes (Serpentes: Reptilia)

The histology of the cloacal scent gland, or anal gland, was examined from a diverse group of 50 snakes. Extensive interspecific morphological variation was observed in the general structure of the gland and the glandular epithelium. Morphological variants were quantitatively scored from eight features: lobate nature of the gland; septa in the glandular epithelium; glandular epithelium having a rough or irregular outer surface; glandular epithelium having a rough or irregular inner surface; thickness of the glandular epithelium; PAS reactivity in the glandular epithelium; Periodic Acid‐Schiff reactivity in the secretory product; and relative size of the cloacal scent gland. The distribution of the encoded morphological variation was compared to an established phylogeny for snakes and used as the basis for a cluster analysis. In both cases there was no apparent relationship between phylogeny and the morphological variation of the cloacal scent gland. Anat Rec 256:127–138, 1999. © 1999 Wiley‐Liss, Inc.     

Anatomy and three‐dimensional reconstructions of the brain of the white whale (Delphinapterus leucas) from magnetic resonance images

Magnetic resonance imaging offers a means of observing the internal structure of the brain where traditional procedures of embedding, sectioning, staining, mounting, and microscopic examination of thousands of sections are not practical. Furthermore, internal structures can be analyzed in their precise quantitative spatial interrelationships, which is difficult to accomplish after the spatial distortions often accompanying histological processing. For these reasons, magnetic resonance imaging makes specimens that were traditionally difficult to analyze, more accessible. In the present study, images of the brain of a white whale (Beluga) Delphinapterus leucas were scanned in the coronal plane at 119 antero‐posterior levels. From these scans, a computer‐generated three‐dimensional model was constructed using the programs VoxelView and VoxelMath (Vital Images, Inc.). This model, wherein details of internal and external morphology are represented in three‐dimensional space, was then resectioned in orthogonal planes to produce corresponding series of “virtual” sections in the horizontal and sagittal planes. Sections in all three planes display the sizes and positions of such structures as the corpus callosum, internal capsule, cerebral peduncles, cerebral ventricles, certain thalamic nuclear groups, caudate nucleus, ventral striatum, pontine nuclei, cerebellar cortex and white matter, and all cerebral cortical sulci and gyri. Anat Rec 262:429–439, 2001. © 2001 Wiley‐Liss, Inc.     

The thyroid gland in bottlenose dolphins (Tursiops truncatus) from the Texas coast of the Gulf of Mexico: normal structure and pathological changes

Fresh thyroid glands (n=60) from Atlantic bottlenose dolphins that died after stranding along the Texas coast between 1991 and 2005 were examined. Organ weight ranged from 11 g in a neonate (length 109 cm) to 58 g in a large (249 cm) male. More typical weights were 25-45 g (mean=30.6 g). Glands tended to be larger in pregnant and lactating females (mean 37.4 g; n=5) than in non-pregnant animals of comparable size. In infancy, the gland tended to be compact, relatively homogeneous, and sometimes partly lobular, but with advancing age it became more lobular, the lobules being defined by fibrous bands. In one 8-year-old female (233 cm), and in a large male (295 cm) aged>25 years the gland was represented by a cluster of lobules. Lobulation was not necessarily accompanied by increased weight, distinguishing it from hyperplasia. With age, variation in follicle size and colloid density tended to increase. Two animals (3%) had adenomas and five (8%) had discrete hyperplastic nodules, not to be confused with lobulation. Five (8%) had macroscopically identifiable colloid-filled cysts (1-4 mm in diameter). Nine animals (15%) had squamous cysts (4-15 mm) containing creamy white fluid. Other abnormalities included patchy or diffuse interstitial fibrosis (six cases, 10%) amyloidosis (two cases), thyroiditis (one case) and vasculitis (one case). No malignant neoplasms were found. Cells presumed to be C cells (light cells, parafollicular cells) were identified immunohistochemically with synaptophysin antibody.     

Morphological changes in the Atlantic bottlenose dolphin (Tursiops truncatus) adrenal gland associated with chronic stress

Beach-stranded Atlantic bottlenose dolphins (n=68) were categorized as either "acutely stressed" (if they died from net entanglement, boat strike, or acute infection; 31 animals) or "chronically stressed" (if they suffered from or died as a result of long-term disease or debilitating injury; 37 animals). No significant differences in mass between the right and left adrenal glands were found within each category. However, the average gland mass (AGM), based on the right and left glands together, was 5.2g for acutely stressed animals and 11.01 g for chronically stressed animals (P<0.001). Significant differences were also found, in terms of the ratio of cross-sectional areas of the cortex to medulla, between acutely stressed (ratio 1.22) and chronically stressed (ratio 1.63) animals (P=0.027). Adrenal glands of acutely stressed animals consisted of 48% cortex, 41% medulla, and 11% other tissue elements (connective tissue, blood vessels and gland capsule), whereas the corresponding figures for chronically stressed animals were 53%, 36%, and 11%. The mean estimated mass values for cortex, medulla and other tissue were, for acutely stressed animals, 2.36, 1.9, and 0.54, respectively, whereas for chronically stressed animals the corresponding figures were 6.06, 4.04, and 1.29 (P<0.001 for each of the three comparisons). Overstaining with haematoxylin (HEM) and immunohistochemical labelling (IHC) of the enzyme phenylethanolamine N-methyl transferase (which converts norepinephrine to epinephrine) were used to determine the percentage of epinephrine-producing cells in relation to the overall cross-sectional area of the adrenal gland. The percentage values in acutely as compared with chronically stressed dolphins were 6.7% and 15.93%, respectively (P=0.021). The results therefore suggest that in bottlenose dolphins chronic stress results in increases in (1) adrenal mass, (2) cortex to medulla ratio, and (3) epinephrine-producing cells within the medulla, giving rise to an increase in the thickness of the medullary band.     

Isolation and primary culture of gill and digestive gland cells from the common mussel Mytilus edulis

As the marine mussel Mytilus edulis is commonly used as a sentinel species, it would be useful to develop a primary culture of the target organs most often in contact with the marine environment. This study reports an improved method for dissociating the digestive gland and gills of M. edulis and considers the effect of mussel storage on cell viability and functionality before culture initiation. Viability and enzymatic activities such as those of esterase and peroxidase were monitored by flow cytometry, a sensitive, objective technique allowing large volumes of cells to be counted within a short time. A primary culture of digestive gland showed more than 75% viability after 72 h. Mussels were maintained in an aquarium containing clean, oxygenated seawater at 12 °C for two days before culture initiation, and dissociation was performed mechanically and chemically with Ca-Mg-free saline to obtain digestive gland cells. Application of nonspecific esterase activity, using fluorescein diacetate (FDA test) coupled with flow cytometry, characterised the functionality of digestive gland and gill cells in culture.     

Morphology of the pituitary gland in ferrets (Mustela putorius furo) with hyperadrenocorticism

Pituitary tumours are the cause of hyperadrenocorticism in a variety of species, but the role of the pituitary gland in hyperadrenocorticism in ferrets is not known. In this species, the disease is mediated by the action of excess gonadotrophins on the adrenal cortex and is characterized by an excessive secretion of sex steroids. In this study, the pituitary gland of four healthy control ferrets, intact or neutered, and 10 neutered ferrets with hyperadrenocorticism was examined histologically following immunohistochemical labelling for adrenocorticotrophic hormone, alpha-melanocyte-stimulating hormone, growth hormone, thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, and prolactin. Immunohistochemistry revealed that somatotrophs, thyrotrophs and lactotrophs were the most abundant cell types of the pars distalis of the pituitary gland in the healthy ferrets. The distribution of corticotrophs was similar to that in the dog and man. In ferrets, as in dogs, the melanotrophic cell was almost the only cell type of the pars intermedia. Gonadotrophs were found in the pars distalis of neutered, but not intact ferrets. All the ferrets with hyperadrenocorticism had unilateral or bilateral alterations of the adrenal gland. In addition, in the pituitary gland of two of these ferrets a tumour was detected. These tumours were not immunolabelled by antibodies against any of the pituitary hormones, and had characteristics of the clinically non-functional gonadotroph tumours seen in man. In some of the other ferrets low pituitary immunoreactivity for gonadotrophic hormones was detected, which may have been due to the feedback of autonomous steroid secretion by the neoplastic transformation of the adrenal cortex. It is concluded that initially high concentrations of gonadotrophins resulting from castration may initiate hyperactivity of the adrenal cortex. The low incidence of pituitary tumours and the low density of gonadotrophin-positive cells in non-affected pituitary tissue in this study suggest that persistent hyperadrenocorticism is not dependent on persistent gonadotrophic stimulation.     

The harderian gland and thermoregulation in the gerbil (Meriones unguiculatus)

Seven experiments with Meriones unguiculatus assessed the thermoregulatory consequence of Harderian secretion and fur anointment with lipids by autogrooming. Harderianectomy reduced the animal's capability to withstand cold (3–5°C) and wetness. During a 9 to 15 min exposure to cold-wet stress glandless animals lost an average of 4.6°C core body temperature, compared to an average loss of 1.6°C among intact animals. A comparable loss in body temperature occurred in animals whose fur lipids were removed with shampooing. Shaved animals coated with petroleum jelly withstood the cold-wet stress with a lesser decrease in body temperature than animals without the exogenous coat of jelly. The in vitro insulating qualities of fur lipids were demonstrated by blocking a cold air stream with various layers of lipids. The degree of insulation was related to the thickness of the lipid layers. Fur lipids were extracted from Harderianectomized and shampooed animals. Relative to controls, both procedures resulted in approximately 40–50% loss of fur lipds. The loss seen in gerbils following Harderianectomy was not found in the rat, golden hamster or C57 and DBA strains of inbred mice. Thus, in the gerbil the behavioral spread of Harderian lipids during a thermoregulatory groom insulated the gerbil from cold and wetness. The use of insulating lipids may be related to the gerbil's ecology in the cold deserts of Mongolia and Northeast China.     

Epstein-Barr virus (EBV)-associated undifferentiated carcinoma of the parotid gland

A case of undifferentiated carcinoma of the salivary gland occurring in the parotid gland of a southern Chinese was reported. Tumour cells showed immunofluorescence for Epstein-Barr virus (EBV)-associated nuclear antigen, and DNA hybridization demonstrated the presence of EBV-DNA in tumour tissue. The findings in this case, together with previous reports, suggest a causal relationship between EBV and salivary gland carcinoma. The relationships between EBV and undifferentiated epithelial tumours of the salivary glands, nasopharynx and thymus are also discussed.     

The genotoxicity of particulate and soluble chromate in sperm whale (physeter macrocephalus) skin fibroblasts

Hexavalent chromium is a marine pollutant of concern, both for the health of ocean ecosystems and for public health. Hexavalent chromium is known to induce genotoxicity in human and other terrestrial mammals. It is also known to be present in both water and air in the marine environment. However, currently there are limited data concerning both chromium levels and its toxicological effects in marine mammals. This study investigated the cytotoxic and genotoxic effects of soluble and particulate hexavalent chromium in sperm whale skin fibroblasts. Both forms of hexavalent chromium induced concentration‐dependent increases in cytotoxicity and genotoxicity indicating that these compounds can be a health risk if the whales are exposed to them. These data support a hypothesis that chromium is a concern in the marine environment in general and for the health of sperm whales in particular. Environ. Mol. Mutagen. 52:43–49, 2011. © 2010 Wiley‐Liss, Inc.     

Gross anatomy,histological, and histochemical analysis of the eyelids and orbital glands of the neonate pygmy hippopotamus (Suina: Choeropsis liberiensis or Hexaprotodon liberiensis,Morton 1849) with reference to its habitat

The pygmy hippopotamus is phylogenetically related to members of both the Suidae and Cetacea. However, differences in their habitats may have resulted in variation in the anatomy and physiology of the ocular adnexa between these species. Therefore, this study focuses on the identification of accessory organs of the eye, which are typical for the pygmy hippopotamus and are comparable to organs present in mammals related to it. Moreover, the secretions produced by the superficial gland of the third eyelid, the deep gland of the third eyelid and the lacrimal gland were examined, as they ensure eyeball protection. In the upper and lower eyelids, numerous serous glands where identified, which were typical for the pygmy hippopotamus and similar as in the Cetacea. This study enabled to identify additional folds in the eyelids of the pygmy hippopotamus. Lymphoid follicles and diffuse lymphocytes were not found in the lymphoid region in the upper or lower eyelids and the third eyelid, which was most likely caused by the age of the studied hippopotamuses. An accurate histochemical analysis revealed that the secretions of the pygmy hippopotamus are very similar to the Sus scrofa. The structural differences between the pygmy hippopotamus and representatives of Cetacea are most likely caused by the fact that most of Cetacea live in saltwater and are exposed to more frequent fluctuations in water temperature compared to the pygmy hippopotamus, which lives in fresh water and does not lead a migratory lifestyle like the Cetacea.     

Juvenile hemangioma (infantile hemangioendothelioma) of the parotid gland associated with cytomegalovirus infection

A case of parotid juvenile hemangioma associated with cytomegalovirus infection is reported. A growing lobulated mass, measuring 30 x 20 mm, was extirpated from the left parotid gland in a 4-month-old male. Histologically, the tumor consisted of cellular plump endothelial cells, stromal cells and residual ductal and acinar elements of the parotid gland. Numerous intranuclear and cytoplasmic inclusions were observed in the ductal cells of the whole parenchymal part of the parotid gland and the residual part of the tumor. Immunohistochemically, some nuclei of the ductal cells possessing these inclusions were positive for the anti-cytomegalovirus antibody but there were no positive findings in the endothelial or stromal cells. Although the present lesion may suggest that the human cytomegalovirus plays some role in the etiology of juvenile hemangioma, it is unknown whether or not this association is incidental.     

Intermediate-sized filament proteins (prekeratin,vimentin, desmin) in the normal parotid gland and parotid gland tumours

Summary Antibodies to different intermediate-sized filament proteins can distinguish cells and tissues of epithelial, mesenchymal, muscle, astrocytic and neural origin. Antibodies to prekeratin, vimentin and desmin have been used to distinguish cells of epithelial, mesenchymal and muscle origin in the normal human parotid gland, and in addition to study some common tumors of this gland. Prekeratin-positive and vimentin-positive cells are found among the tumor cells in the pleomorphic adenomas. In contrast the tumor cells of the mucoepidermoid tumors and squamous cell carcinomas are prekeratin-positive but vimentin-negative.Supported by the Deutsche Forschungsgemeinschaft (Ca 93/1-1) and by the Hamburger Stiftung zur Förderung der Krebsbekämpfung     

Gross morphology of the alimentary canal and seasonal variation in feeding of Noemacheilus montanus (McClelland)

Noemacheilus montanus (McClelland) is a bottom feeder Omnivorous fish of Garhwal hillstreams. The alimentary canal is short and the stomach consists of a corpus and a pylorus portion. As it consumes more animal food than the vegetable food, it may be better called Carni-omnivore. The study of GSI for different months revealed that the feeding intensity attains 2 peaks during a year, first in December and second in June. The change in feeding intensity may be correlated with the availability of food items in nature.