Light and electron microscopic findings are presented for the first time on a species of amphipod whale louse, Cyamus ceti, with reference to the paired photoreceptor structures of the head. Whale lice are crustacean ectoparasites of large, slow moving whales. Twenty-two known species parasitize mainly baleens but also toothed whales. Samples were collected from Alaskan bowhead whales during an Eskimo hunt. The photoreceptors, or compound eyes, were sessile and located on the dorsal cephalon. Each photoreceptor contained approximately 50 visual ommatidial units. The general organization was similar to other amphipod crustacean compound eyes. The single ommatidial unit consisted of 1) an overlying cuticle, 2) crystalline cone secreted by cone cells, 3) a fusiform layered rhabdom, 4) surrounding pigmented retinular cells, and 5) basal lamina and axon. The cuticle over each eye was translucent, convex, and thinner than the rest of the cranial cuticle. The photosensitive rhabdom contained a central core of alternating microvillous projections, and the rhabdomere unit was formed by five or six retinular cells. There were numerous electron-dense and electron-lucent granules within the cytoplasm of the retinular cells, corresponding to visual pigment or reflecting granules. The eyes most likely play a role in detecting light direction, duration and/or intensity, which may direct molting, reproduction, or other functions of this cetacean ectoparasite.
The pathophysiology of clinical peptic ulcer, which is diverse for duodenal, chronic gastric or stress ulcer in humans, has been only partially elucidated by experimental animal studies. A central role of vascular disturbance and acid back diffusion for human stress and animal stress ulcers is evident, whereas a complex and variable set of functional disorders may relate to duodenal ulcer, though the role of acid is paramount. Mucosal resistance factors are of major importance in all types of ulcer and are of particular interest in chronic gastric ulcer. The importance of selecting, for anti-ulcer drug testing, appropriate ulcer models is emphasized, and more extensive use of chronic experimental ulcer healing rate changes, mucus glycoprotein analysis, and cytoprotective changes is recommended. Novel compounds such as pirenzepine, which act on some muscarinic receptors, will help elucidate ulcer pathophysiology as well as provide medical therapy, particularly since all postganglionic vagal transmitter substances in gastric or duodenal mucosae have not yet been identified.
In vitro studies on rat hepatic lysosomal stability, as assessed by release of beta-glucuronidase, were undertaken to demonstrate the comparative influence of surface-active agents which act by various mechanisms. Bile acids, short chain alcohols, acetylsalicylic acid, and Triton X-100 were studied, as well as their interaction with zinc. The detergents and alcohols enhanced release of this acid hydrolase in a dose dependent fashion, but acetylsalicylic acid did not. Zinc antagonized these effects in a non-specific manner. It is postulated that zinc stabilized lysosomes by direct action on the lysosomal membrane, such as by surface protein interactions, but the precise mechanism remains unknown.
The spontaneous epithelioma of the Japanese newt, Cynops pyrrhogaster, is a useful animal model for study of development and regression of papillomata of suspected viral origin. Therefore, ultrastructural studies of this cutaneous tumor were undertaken in order to characterize this model further. The ultrastructure of normal Cynops pyrrhogaster epidermis resembled teleost more than anuran epidermis. Surface cells of the bilayered stratum corneum were covered by micro-ridges and contained prominent nuclei, unlike the stratum corneum of mammals. Capillary endothelial cells contained unique small dense granules. Principal changes in tumors consisted of hyperplasia of stratum granulosum cells, increased melanin bodies in corneal cells, distorted configurations and aberrant location of outer corneal cells, which also demonstrated irregularity of micro-ridges and increased mucin and vacuole content. Intercellular spaces were enlarged between all cell types. Virus-like particles were observed in approximately 40 percent of tumors, particularly in the middle of the tumor.
An ultrastructural analysis by transmission and scanning electron microscopy was carried out on normal epidermis of six southern right whale (Eubalaena australis) calves which stranded over a period of several months at Peninsula Valdes, Argentina. This was undertaken to 1) provide the first normal skin ultrastructural data on this highly endangered species which is known to display skin pathology in some instances, and 2) to elucidate further the integumentary specializations which have developed in diving marine mammals. Southern right whale lipokeratinocytes demonstrated parakeratosis and numerous intracellular lipid bodies, keratin and melanosomes, as reported for other cetacean species, but showed several unique ultrastructural features as well. These included a high prevalence of intranuclear inclusion bodies resembling small fragments of cytoplasmic keratin, and close structural relationship between cytoplasmic lipid droplets and the nucleus. The subcellular morphology supported the concept of possible nuclear import of cytoplasmic keratin and lipid metabolites through enlargements of the nuclear pore complex or other disruptions of the nuclear envelope. The light microscopy and scanning electron microscopy also revealed an irregular contour of the lipokeratinocytes which comprised the thick stratum externum, and surface flaking of the outermost cells which were covered by stubby microvillous-like remnants of intercellular junctions. These results thus suggest that the long-tem aquatic evolution of this cetacean species has resulted in a number of integumentary specializations and that investigation of their submicroscopic cytology may help elucidate the general cell biology of nuclear-cytoplasmic interactions.
Investigation of atrial and ventricular cardiac ultrastructure by transmission and scanning electron microscopy of the adult Japanese newt, Cynops pyrrhogaster, has revealed some unique cell types and features in this amphibian. Typical urodelan-type thin trabeculae composed of myocytes with conventional architecture of loosely scattered myofibrils were observed. Scarce granules of variable size and density were seen in atrial myocytes, and some Purkinje-like fibers were observed. Unique structures included scattered endocrine-like cells with dense cytoplasmic granules in the epicardial spaces, a distinct granular cell found occasionally on the endocardial surface projecting into the lumen of the cardiac trabeculae, and peculiar granulated inclusions in the myoplasm. The function of these possible endocrine cells remains undetermined. It is important to characterize the heart of this species, as it has recently been proven to be an excellent model for prolonged experimental studies in vitro.
Einleitung Die Larynxpapillomatose auch rezidivierende respiratorische Papillomatose (RRP) wird durch das Humane Papilloma Virus (HPV) verursacht. Die Rolle von HPV in der Pathogenese des sinonasalen invertierten Papilloms ist noch nicht abschließend geklärt. Ein synchrones Auftreten haben Oliver et al. 2019 erstbeschrieben.
The human species is perhaps unique for its high incidence of spontaneous, chronic ulcer of the glandular mucosa of the stomach and duodenum. Nevertheless, spontaneous ulcers, usually of the stomach, commonly occur in many domestic animals. Some of these lesions are chronic and they may occur in either the glandular or squamous-lined regions of the stomach. As with the human disease(s) the pathogenesis in domestic animals is multifactorial, poorly understood, and variable between and within species. Some parallelisms exist in aggressive and defensive factors, but parasitic factors, via gastrinemia, and a histaminic factor via diet may occur in some animal ulcers. Underlying environmental stresses, of debated importance with the human disease but of proven importance in several rat ulcer models, may play a key role in some spontaneous gastric ulcer situations in swine and cattle. This is manifest in crowding and transporting situations. Seasonal, age, and weaning factors also alter the incidence of ulcer in cattle. Psychologic/environmental stress-related factors, as well as drug and physiologic stress factors appear to upset the balance in the horse between resistance and aggressive mucosal factors. Dietary factors which are highly important in ulcer disease in swine and chickens, have not yet been incriminated in spontaneous, equine ulcer disease. More investigation of the pathogenesis of domestic animal ulcers will prove useful for both human and veterinary medicine in terms of a) elucidating pathogenetic mechanisms for all species, b) may provide new animal models for study, and c) may enhance prevention of such lesions in domestic animals for economic and humanitarian reasons.
