A morphological study of the gross and light microscopic lesions of infectious anaemia in Atlantic salmon (Salmo salar).

Infectious anaemia in Atlantic salmon (Salmo salar) was studied by recording gross and light microscopic changes, and the development of lesions was studied in relation to haematocrit values. Gross lesions were characterised by ascites formation, congestion and enlargement of liver and spleen, congestion of the foregut and petechiae in the peritoneum. Histologically, lesions were demonstrated in the liver, being characterised by congestion in early stages (that is, haematocrit values around 25), dilatation of the sinusoids, and in later stages (haematocrit values 25 to 15) formation of blood-filled spaces bearing morphological resemblance to peliosis hepatis. At low haematocrit values (around 10), these changes comprised large areas of the liver parenchyma, that is, blood-filled areas coalesced, presenting islets of degenerate and necrotic hepatocytes. At this stage, haemorrhagic necroses were found. Spleen and kidney lesions were characterised by congestion. In the foregut, congestion and bleeding in lamina propria were observed. Liver lesions became more disseminated and severe with decreasing haematocrit values. Hypoxia due to anaemia alone cannot fully explain the development of the liver lesions.     

Electron microscopic study of the porcine choroid plexus epithelium

The choroid plexus (CP) is a highly vascularized organ in the brain ventricles which acts as the main producer of cerebrospinal fluid (CSF). A study of the surface ultrastructure of the porcine CP was performed using scanning and transmission electron microscopy. The vascular walls of the capillaries were fenestrated. Epiplexus cells of different morphology were abundant on top of the epithelial surface. Two types of epithelial cells were present, characterized by the presence or absence of microvilli. Some epithelial cells contained cilia while other cells had large secretory protrusions called blebs. In the choroid epithelium of the lateral ventricles, some cells with large depressions were present. Cells with peduncles, such as recently discovered in the buffalo, could not be recognized. The variability of the choroidal surface structures clearly indicates the active role of the CP in the formation and maintenance of the CSF and its components.     

Gross and microscopic pulmonary lesions of camels from Eastern Ethiopia

Camels are important animals for pastoralists in the northeastern, eastern, southeastern and southern parts of Ethiopia. This paper reports on abattoir study of respiratory lesions in 104 adult camels at the Dire Dawa abattoir (88 male and 16 female). The study showed 98% of the examined lungs had one or more lesions. The most common lesions were pulmonary fibrosis (50.00%), pneumoconiosis (34.62%), hydatid cyst (30.80%), pulmonary abscess (3.85%) and parasitic bronchopneumonia (0.96%). The distribution of pneumoconiosis and hydatid cyst varied significantly (p < 0.05) among different lobes, the highest being seen in the caudal lobe. For the different lesions there was no significant (p > 0.05) difference in distribution among male and female camels. Possible explanations for the occurrence of the lesions are discussed. And recommendations forecasted are made.     

A light and electron microscopic study on abomasal globidiosis in Somali goats

Abomasum from apparently healthy Somali goats with globidiosis showed pin-head sized nodules embedded in the mucosa. The nodules consisted of encapsulated cysts, containing mature or immature schizonts. Glandular atrophy and lymphohistiocytic cell reaction were often found in the vicinity of these cysts. The fine structure of immature and mature cysts is described in details. The mature cysts contained elongated, spindle shaped merozoites (type I) or shorter, ovoidal merozoites (type II). Some mature cysts also had basophilic granular bodies among the merozoites. Type I and type II merozoites were morphologically different from those earlier described in goats.     

Canine hyperplastic intraepidermal pustular and suprabasal acantholytic dermatosis with features of human pemphigus vegetans

Pemphigus vegetans is a rare autoimmune blistering acantholytic dermatosis of humans that combines unusually hyperplastic and verrucous pustular skin lesions and mucosal erosions. We report herein the clinical, histopathologic, and immunologic findings in a dog whose lesions resembled, but were not identical to, those of human pemphigus vegetans. A 4-year-old male Greater Swiss Mountain Dog presented with multifocal cutaneous verrucous and crusted papules and pustules, as well as skin and mucosal erosions and ulcers. Microscopic lesions consisted of exophytic papillated epidermal hyperplasia, superficial and deep intraepidermal acantholytic neutrophilic and eosinophilic pustules, and suprabasal epidermal clefts leaving rounded basal keratinocytes at the bottom of the vesicles. Direct and indirect immunofluorescence revealed antikeratinocyte IgG autoantibodies. Immunoprecipitation immunoblotting and immunoabsorption experiments with recombinant canine desmogleins confirmed that autoantibodies recognized desmoglein-1. In this dog, clinical and histopathologic features resembled those of human pemphigus vegetans, while circulating autoantibodies against canine desmoglein-1 were solely identified. This antigen target is different from that of the human disease in which antidesmoglein-3 autoantibodies are detected most commonly.     

A method for the sequential study of eimerian chromosomes by light and electron microscopy

In the present study, the authors describe a simple method to isolate chromosomes from eimerian oocysts and to submit them to sequential study by light and electron microscopy. This method includes a reliable and reproducible technique for transferring eimerian chromosomes from slides to grid that fulfills the essential requirements for generalized use in cytogenetics. In addition, this method overcomes the difficulty of the resistance of protozoan oocysts to disruption and permits the release of intact meiotic chromosomes. The observation by the authors of synaptonemal complexes in meiotic chromosomes of different Eimeria species by applying the above-mentioned method to oocysts revealed its importance to future applications.     

Scanning electron microscopic study of the functional anatomy of the porcine oviductal mucosa

A three-dimensional model has not been clearly established for the porcine oviductal mucosa. The oviducts of 12 cyclic sows were examined by Scanning Electron Microscopy to study the structure and nature of the mucosal arrangement of the oviduct. Epithelial cyclic changes were also studied. The oviductal infundibulum is an asymmetric funnel-shaped structure surrounding the ostium, in which a wide and a narrow side can be distinguished. The mucosa is more complex in the narrow side, showing numerous and tortuous longitudinal primary folds, while the mucosa becomes simpler in the wide side. Around the ostium abdominale wide secondary folds form cul-de-sacs, with their opening pointing in ovarian direction. Areas between folds throughout the lumen of the oviduct show a high-degree of complexity. Inter-fold spaces are occupied by a system of irregular grooves and pockets, with the presence of basal crypts in the caudal oviduct. Marked variations were observed in the oviductal epithelium depending on the oviductal segment, basal or apical areas of the folds, and phase of the oestrous cycle. Cyclical changes were observed in the infundibulum and ampulla, so that prominent and numerous ciliated cells lined apical areas of the folds in the follicular phase; whereas secretary cells were predominant throughout all areas of epithelial surface in the luteal phase. The oestrous cycle phase appeared do not affect the epithelial population cells of the caudal segments of the oviduct: ciliated and secretory cells uniformly lined apical and basal areas of the folds. The topography of the oviduct provides a complex system of regulation, which may influence not only the passage of cells, but also movement of fluid within the oviductal canal.     

Spontaneous Pancreatic beta cell tumor in the rat. A light and electron microscopic study.

Fine structural study of a pancreatic neoplasm found at autopsy of a 27-month-old female Long-Evans rat showed that the tumor consisted of, and derived from beta cells of the islets of Langerhans.     

A scanning and transmission electron microscopic study of rotavirus-induced intestinal lesions in neonatal gnotobiotic dogs

Neonatal gnotobiotic dogs orally inoculated with canine rotavirus had ultrastructural changes limited to the jejunal and ileal regions of the small intestine. Early scanning electron microscopic findings consisted of swollen villus epithelial cells, denuded foci on intestinal villi, and slight to moderate villus atrophy. Later changes were slight villus atrophy with no denuded intestinal villi. Transmission electron microscopic changes in villus epithelial cells from 12 to 48 hours post-inoculation included: rotavirus particles associated with intracytoplasmic vacuoles near the terminal web and apical tubules; viral particles in dilated cisternae of rough endoplasmic reticulum; and moderate numbers of necrotic cells having no microvilli, swollen mitochondria, membrane-bound lipid-like material in the cytoplasm, clumped chromatin around the periphery of the nucleus, and disruption of the cytoplasmic membrane. In jejunum and ileum at 72 to 154 hours post-inoculation, there were fewer necrotic villus epithelial cells and fewer virus particles. In addition, the ultrastructural morphology of the majority of the villus epithelial cells was similar to crypt epithelium. These studies showed that rotavirus infected the villus epithelial cells with subsequent propagation of the rotavirus and destruction of villus epithelial cells.     

A light and electron microscopic study of the leukocytes of channel catfish (Ictalurus punctatus)

A light and electron microscopic study of channel catfish (Ictalurus punctatus) white blood cells was carried out. The white blood cells of channel catfish consist of lymphocytes, neutrophils, thrombocytes and monocytes. A fifth cell type is illustrated and described which could not be characterized. These leukocytes are characterized and compared with their mammalian counterparts.     

A sequential study of experimental infection of pigs with porcine circovirus and porcine parvovirus: immunostaining of cryostat sections and virus isolation

The sequential tissue distribution of virus was investigated using virus isolation and immunofluorescence tests in 1-day-old piglets inoculated with porcine circovirus 2 (PCV2) and/or porcine parvovirus (PPV). Enlarged mesenteric lymph nodes were seen in the pig inoculated with PCV2 alone and killed at 26 days post-inoculation (PI). One of the pigs inoculated with PCV2 and PPV and killed at 21 days PI had an enlarged liver. The pig killed at 26 days PI in this group had enlarged liver, kidneys and heart. Histopathological changes were seen in lymphoid tissues of the pigs inoculated with PCV2 alone and killed at 14 and 26 days PI. Similar, but more severe, lesions were observed in the pigs infected with PCV2 and PPV and killed from 10 days PI onwards. Histological lesions of nephritis, pneumonia and hepatitis were also apparent in these animals. Mild nephritis was also seen in the pigs infected with PPV alone and killed at 14 and 26 days PI. Moderate amounts of PPV antigen were detected in tissues from the pigs inoculated with PPV alone and killed at 14 days PI. Low levels of PCV antigen were detected, mainly in lymphoid tissues, in the pigs inoculated with PCV alone and killed at 14 days PI. Low to moderate amounts of PCV antigen were detected in a wider range of tissues in the pig in this group killed at 26 days PI. In the pigs inoculated with both viruses, PPV antigen was detected in tissues of pigs killed from 3 to 26 days PI with maximal amounts detected between 6 and 14 days PI. PCV2 antigen was detected in low to moderate amounts in the tissues of pigs killed at 14 days PI. Large amounts of PCV2 antigen were detected in most of the tissues from pigs in this group killed between 17 and 26 days PI. Virus isolation results for PCV2 generally correlated well with the results for immunofluorescent staining. PPV was isolated from almost all tissues from pigs inoculated with PCV2 and PPV, a much higher incidence of positive tissues than observed for immunofluorescent staining.     

Equine laryngeal hemiplegia. Part I. A light microscopic study of peripheral nerves

This light microscopic investigation of 15 Thoroughbred horses provided substantial evidence for the classification of equine laryngeal hemiplegia as a distal axonopathy. Morphologic and morphometric examinations were performed on resin embedded recurrent laryngeal nerves from control, subclinical and clinical laryngeal hemiplegic animals. In the latter group of animals some distal hindlimb nerves were also examined. A distally graded loss of myelinated fibres selectively affecting those of large diameter was demonstrated in both left and right recurrent laryngeal nerves. Morphologic evidence of similar pathological changes in long hindlimb nerves was also present. An explanation for the early involvement of the cricoarytenoideus lateralis muscle in the course of laryngeal hemiplegia, was offered by the demonstration of more large diameter fibres in the branch of the recurrent laryngeal nerve innervating it, thus making it more susceptible to the disease process.     

A light microscopic and immunocytochemical study of the gastrointestinal tract of the ostrich (Struthio camelus L.)

Although the histological features and endocrine cells of the gastro-intestinal tract of the chicken have been well studied, little is known about these features of the gut of the ostrich. The present study was undertaken to elucidate the histology and peptide-storing endocrine cells of the ostrich. As a rule the histological features of the gastro-intestinal tract of the ostrich corresponded to that of the fowl. However, certain differences were observed. The superficial proventricular glands were simple, branched tubular glands, while the deep proventricular glands were restricted to a slipper-shaped area and extended into the muscularis mucosae. The gizzard had a variably developed muscularis mucosae, a feature that seems to be unique to the ostrich. The villi of the small intestine were long and branched profusely, forming a labyrinthine surface. No Paneth cells were observed. The mucosa of the ceca and the first part of the rectum was thrown in large circular folds, forming a compressed spiral. Numerous melanocytes were seen in the submucosa and the connective tissue around the bloodvessels of the muscle layers at the tips of the ceca. A well developed subserosa was present throughout the gastro-intestinal tract. Endocrine cells immunoreactive to somatostatin, glucagon, gastrin, bombesin, neurotensin, substance P and pancreatic polypeptide were detected in the gastro-intestinal tract of the ostrich. The topographical distribution of those endocrine cells immunoreactive to glucagon, bombesin, neurotensin and substance P differed from that of the chicken. The results of this investigation inferred that at least one of the gut peptides of the ostrich (secretin) to be structurally different from its counterparts in mammal and chicken. Molecular heterogeneity of somatostatin was observed in endocrine cells situated in the deep ventricular glands of the ostrich.