Morphologic features of lymph vessels in caprine hemal nodes

The distribution and characteristics of lymph vessels in caprine hemal nodes were studied after glutaraldehyde fixation and epoxy resin embedding. Histologically, the lymph vessels were characterized by thin walls and wide lumens containing inspissated lymph in which a few cells were suspended. The lymph vessels contrasted sharply with adjacent blood sinuses that were filled with elements of circulating blood. A circumferential lymph vessel in the cortex joined radial branches in the medulla that met at the hilum to drain through a large efferent lymph channel. Ultrastructurally, the lymph vessel wall comprised endothelial cells supported by a continuous basal lamina, collagen fibrils, and adventitial reticular cells. The cytoplasm of endothelial cells had fenestrations, plasmalemma-associated vesicles, vacuoles, and focal splits that enclosed large compartments. Many compartments contained erythrocytes and lymphocytes. Modifications of the endothelial cells signified their endowment with features that favored transendothelial transport. The distribution of lymph vessels and the finding of only efferent lymph channels are related to the roles of hemal nodes in blood storage by hemoconcentration and in immune defense mechanisms.     

Thymoma and multiple thymic cysts in a dog with acquired myasthenia gravis

An anterior mediastinal cystic lesion in an 11-year-old mongrel dog was examined. The dog showed dysbasia and vomiting due to megaoesophagus, and anterior mediastinal round mass lesion, approximately 35 mm in diameter, was found by X ray. Based on clinical examinations, the dog was diagnosed as acquired myasthenia gravis and was successfully controlled by anticholinesterase treatment for approximately 4 months. The dog died of thermic stroke and was necropsied. Grossly, fatty tissues with cysts containing yellowish fluid and white nodules were found in the anterior mediastinal area. Histopathologically, multiple cysts, neoplastic tissues, and atrophic thymus were found within the examined tissues. The cysts were lined by thin wall consisting of ciliated long cuboidal and non-ciliated round cells and were filled with eosinophilic colloidal fluid. Some extended cysts contained neoplastic foci within their lumen and walls. The neoplastic tissues consisted of mixed population of large epithelial cells with abundant clear cytoplasm and large oval nuclei, and lymphocytes. Immunohistochemically, proliferating epithelial cells were intensely positive for keratin and cytokeratin, and more than half number of infiltrating lymphocytes were intensely positive for CD3 suggesting T cells. All these findings indicate the neoplastic lesion is thymoma and multiple cysts are considered as thymic or brachial cleft cysts.     

Granulomatous encephalitis in a neurologically impaired goat kid associated with degeneration of Neospora caninum tissue cysts.

Congenital Neospora caninum infection was diagnosed in a Saanen goat from a farm in southern Brazil. The kid was unable to nurse and had difficulty rising, ataxia, and opistothotonos. The neurologic signs became more severe 3 days after birth, when it was euthanized. No gross lesions were observed at necropsy. Multifocal infiltrates primarily of mononuclear cells, nodular microgliosis, and perivascular cuffs of lymphocytes, plasma cells, and few neutrophils were observed in the brain, mostly in the cortex and adjacent to ventricles. Rare multinucleate giant cells were observed adjacent to inflammatory foci. Several tissue cysts with a thick wall that reacted strongly with polyclonal antiserum to N. caninum were in the cerebral cortex and medulla oblongata. Lesions were also present in heart, lungs, and liver, but N. caninum tachyzoites were not found. Distinguishing features in this goat kid included neurologic impairment resulting from congenital infection with N. caninum and the presence of granulomatous inflammation with rare giant cells associated with degeneration of tissue cysts.     

Ultrastructural changes related to the lymph node haemorrhages in acute African swine fever

In order to determine the pathogenic mechanisms involved in lymph node haemorrhages in acute African swine fever ( ), eight pigs were inoculated with virus, strain Malawi'83. Lymph node haemorrhages were observed from three days post infection (dpi) onwards, coinciding with ASF virus replication in monocytes and macrophages adjacent to stimulated endothelial cells, phagocytic stimulation of capillary and small-vessel endothelial cells, increase in the number of fenestrations of endothelial cells, and endothelial cell loss, as well as clusters of blood cells and necrotic material beneath the endothelium. Vascular lumina were blocked by platelet plugs and fibrin microthrombi. These phenomena became more marked as the disease progressed. At five dpi, virus replication was also found in circulating neutrophils. At seven dpi, lesions were more intense and were accompanied by virus replication in sinus and capillary endothelial cells, and in other cell populations including pericytes, fibroblasts, smooth muscle fibres and reticular cells. The results obtained in this study suggest that lymph node haemorrhages are related to endothelial stimulation and the onset of disseminated intravascular coagulation. Virus replication in vessel wall cells occurs only in the final stages of the disease and plays a secondary role.     

Histochemical study of the accumulation of copper in the liver of sheep

Six Merino sheep were dosed orally with a 0.2 per cent solution of copper sulphate, six others were undosed controls. Liver biopsies were obtained and stained for copper by the p-dimethylaminobenzylidene rhodanine (DMABR), rubeanic acid (RA) and ferricyanide (FCN) methods for examination by light microscopy. The initial and most marked accumulations of copper were found within the hepatocytes of the centrilobular zones. Increased copper loading resulted in copper deposition extending through the midlobular to the periportal zones. The deposition of copper was unequal between hepatocytes and with increasing copper loading isolated hepatocytes became packed with copper containing granules. Copper appeared within Kupffer cells and macrophages of portal triads. The first Kupffer cells to be positively stained and the greatest number of such cells were adjacent to the central veins. Accumulation of copper was demonstrated with hepatocytes at copper concentrations equivalent to 44.3 micrograms copper g-1 liver wet weight. The FCN method provided a more satisfactory demonstration of intracellular copper than the RA technique and the latter was better than the DMABR method. However, the DMABR technique provided the clearest morphological details.     

Polyostotic cystic bone lesions in a dog

The clinical, radiological, and pathological features of a polyostotic cystic bone lesion in a 9-month-old Doberman Pinscher are described. The patient was diagnosed as having nutritional secondary hyperparathyroidism at 6 weeks of age and after dietary correction it remained clinically normal until 9 months when there was sudden left hind-limb lameness due to a pathological fracture through a cystic lesion in the distal femur. Radiography revealed additional cystic structures in the metaphyses of the left radius, and left and right tibia. Pseudofractures were associated with two of the cystic lesions.
In some areas the cysts were crossed by trabeculae and in others there were bony ridges on the inner cystic wall. The cavities were lined with flesh-coloured fibrillar material which formed a lacy network extending into cavities. Histologically, multiple small cysts were present adjacent to the larger cavities noted radiographically. The secondary spongiosa and the metaphyseal periosteum were the major abnormal tissue sites. The small cysts appeared to arise in an oedematous and congested metaphyseal spongiosa. The cysts were accompanied by small foci of intense osteoclasis but unattended by compensatory bone production, and the consequent possibility of pseudofractures is an important clinical consideration. Earlier reports demonstrated that resolution of the lesions will follow surgical drainage and curettage of the cystic cavity. Of six cases of polyostotic cystic bone lesions observed in the dog, five were in the Doberman Pinscher breed.     

Effect of feeding green onions (Allium ascalonicum) to White Chinese geese (Threskiornis spinicollis).

Sudden increase in mortality was observed in 2 different flocks of mature breeder geese fed green onions. At necropsy, birds had pale epicardium with random petechiation, sanguinous fluid accumulation in the pericardial sac, and mild swelling of the liver and spleen. Histologically, there was accumulation of hemosiderin in hepatocytes, Kupffer cells of the liver, macrophages, and renal tubules. There was also moderate to severe hepatic necrosis, vacuolation of hepatocytes, splenitis, and renal tubular nephrosis. To assess the effects of green onion ingestion, 2 feeding trials were carried out in 3 mature White Chinese geese. In the first trial, onions were thoroughly mixed with pellet maintenance ration. In the second trial, onions were offered in a separate trough from the pelleted diet. During the 21 days of experiments, the red blood cell count and hematocrit decreased, whereas the polychromasia and reticulocyte estimate increased. The blood changes were more marked in birds from the second feeding trial. Gross and histologic changes were similar in both trials. Mild swelling and severe darkening of the liver were the only significant findings at necropsy. Histologically, the liver looked similar to that seen from the field outbreak. The liver contained moderate amounts of hemosiderin in the hepatocytes and Kupffer cells, and had centrolobular necrosis and vacuolation of hepatocytes. This experimental study demonstrated that anemia and liver pathology could be caused by ingestion of onions. Furthermore, Heinz bodies are not a consistent finding in the blood of geese fed onions.     

Ganglion cysts in a juvenile dog

Ganglion cysts were diagnosed in a 4-month-old male Afghan Hound. Grossly, the subcutaneous ovoid cysts around the caudal right elbow joint and left ischiatic tuberosity had abundant mucinous fluid and internal folding. The lesions recurred twice around the elbow joint after surgical removal. Neither cyst communicated with the joint cavity. Histologically, the cyst wall consisted of inner myxomatous and outer immature connective tissue. Some parts of the cyst wall had various stages of myxoid metaplasia of collagen tissue leading to new cyst formation. Ultrastructural study revealed that cells in the myxoid metaplastic lesion had well-developed cytoplasmic secretory elements, including abundant rough endoplasmic reticulum, Golgi apparatus, and many smooth-walled vesicles. These ganglion cysts apparently resulted from the metaplasia of fibroblasts to secreting cells.     

An epizootic among knots (Calidris canutus) in Florida. II. Ultrastructure of the causative agent, a Besnoitia-like organism.

Multinucleated cysts near the luminal surface of the thoracic aortas of diseased knots (Calidris canutus) were similar to besnoitia cysts. Ultrastructurally, the cyst had four distinct layers. The central area included a vacuole that contained a sporozoan with a conoid, polar ring, micronemes, rhoptries, nucleus, mitochondria, dense bodies, a lipid-like vacuole and endoplasmic reticulum. External to the vacuole was a layer with organelles typical of vertebrate cells. The wall of the cyst was irregular in thickness and was bound by a strongly osmiophilic membrane. There was a loose, acellular area of intertwined strands between the cysts wall and layer of organelles.     

A light microscopic comparison of the cysts of four species of Sarcocystis infecting the domestic reindeer (Rangifer tarandus) in northern Norway

Fresh preparations of micro-isolated sarcocysts from skeletal and cardiac muscle of 12 reindeer were examined by light microscopy. On the basis of cyst structure and cyst wall structure 4 Sarcocystis spp. could be differentiated. New names have been proposed for 2 previously unnamed Sarcocystis spp. of reindeer, and S. grueneri has been redefined.S. rangiferi n. sp. had macroscopic cysts in skeletal muscle measuring 2106×403 µm. The cyst wall protrusions were finger-like and measured 13.2×6.7 µm. The cysts were surrounded by a layer of fibrillar material.S. tarandi n. sp. had micro- to macroscopic cysts primarily in skeletal muscle, but a few cysts were found in the heart of one animal. In skeletal muscle the cysts measured 999×75µm; in the heart the cysts were shorter and wider. The cyst wall protrusions were fingerlike and measured 9.2×2.2 µm.S. grueneri had micro- to macroscopic cysts in cardiac muscle measuring 581×137 µm. The cyst wall was thin and relatively smooth with no visible protrusions.Sarcocystis sp. had micro- to macroscopic, slender cysts in skeletal muscle measuring 916×64 µm. The cyst wall had tightly packed, short, knob-like protrusions. The cysts of this species were previously classified as cysts of S. grueneri.     

Pathology of specific-pathogen-free chickens inoculated with H5N1 avian influenza viruses isolated in Japan in 2004

Specific-pathogen-free chickens inoculated with H5N1 highly pathogenic avian influenza (HPAI) viruses isolated in Japan in 2004 were investigated pathologically. The chickens inoculated intravenously with the viruses died within 26 hr after inoculation. Macroscopically, minimal necrosis of the tip of the comb, and hemorrhages of the palpebral conjunctiva, liver, cerebellum, and muscles were rarely observed. Histologically, dead chickens had minimal focal necrosis of hepatocytes with fibrinous thrombi in sinusoids, mild necrosis of splenic ellipsoids with fibrinous exudation, minimal necrosis of the brain, mild necrosis of epidermal cells of the comb with congestion of the lamina propria, and hemorrhages and edema of the lamina propria of the conjunctiva. Virus antigens were seen in the sinusoidal endothelial cells and hepatocytes in the liver, the capillary endothelial cells of the spleen, the capillary endothelial cells and cardiac myocytes in the heart, the capillary endothelial cells and necrotic nerve cells in the brain, the capillary endothelial cells in the lamina propria of the comb, the renal tubular epithelial cells, and the pancreatic acinar cells. The chickens inoculated by natural infectious routes died within 1-4 days after inoculation. Macroscopically, some chickens had hemorrhages in the conjunctiva, edematous swelling of the face and wattles, hydropericardium, hemorrhages of the proventriculus and bursa of Fabricius, increased secretion of tracheal mucus, and congestion and edema of lungs. Histologic lesions by natural infectious routes were similar to those by intravenous inoculation, except for the pancreatic necrosis. This study suggests H5N1 HPAI viruses isolated in Japan in 2004 cause pathologic conditions similar to natural cases.     

Histochemischer Nachweis von Aktin in den terminalen Darmgäßen des Huhnes*

Using fluorescence microscopy, cytoskeletal actin filaments were found in the terminal blood vessels of chicken intestine. Direct detection with Tetramethylrhodaminyl-Phalloidin showed a high concentration of actin filaments in the tunica media and a low concentration in the endothelium. Actin filaments were also present in the endothelial cells of capillaries and to a higher degree also in the pericytes. The wall of the veins in the villi, which were concentrically surrounded by bundles from the tunica muscularis mucosae, had a greater number of actin filaments than the wall of the venules present in the villi. The discussion touches on the possibility that the microfilaments play a role in blood regulation, especially in the capillaries.     

Determinants of weak femoral artery pulse in dogs with mitral valve prolapse

In three substudies encompassing 247 dogs from two breeds predisposed to myxomatous mitral valve disease (MMVD), femoral artery pulse strength was palpated and related to potential explanatory factors, including quantitative echocardiographic measures of MMVD, aortic and femoral artery diameter and wall thickness and blood pressure. In addition, in 109 Cavalier King Charles Spaniels (of which 61 were included in the three substudies mentioned above), the relation between femoral artery pulse strength and presence of thrombocytopenia was investigated. In 26% of the dogs, a pulse 相似文献   

Ultrastructural Observation of Nasal and Pulmonary Intracellular Pasteurella multocida A:3 in Rabbits

Sixteen 8- to 9-week-old Pasteurella multocida-free rabbits were divided into two equal groups. Eight rabbits in one group were inoculated intranasally with P. multocida type A:3. The other eight were inoculated intranasally with phosphate-buffered saline and used as controls. Nasal swabs taken before and after inoculation were cultured for bacterial isolation. Post-mortem nasal swabs and lung samples were cultured for bacteriological isolation. Nasal mucosa and lung samples were collected and processed for transmission electron microscopy. Pasteurella multocida was isolated from the nasal cavity of all infected rabbits and from the lungs of four infected rabbits. Degenerative ultrastructural changes in epithelial cells and endothelial cells were seen in the infected rabbits. Deciliation of the cilated epithelium and hyperplasia of the goblet cells in the nasal mucosa were noted. Thickening of the alveolar septa due to hyperplasia of type II pneumocytes, swelling of the endothelial lining of capillaries and infiltration of inflammatory cells were also observed. Intracellular invasion of the nasal epithelial cells and of type II pneumocytes by the organism was observed. Coccobacilli were observed in membrane-bound vacuoles in the cytoplasm of these cells. The vacuoles were adjacent to the host-cell mitochondria and some of these vacuoles appeared to be fused to the mitochondrial membrane. Some type I pneumocytes with intracellular membrane-bound vacuoles containing bacterial cells showed protrusions, which appeared to detach into the alveolar lumina. These results indicated that P. multocida serotype A:3 in rabbits can invade the epithelial cell and cause structural changes in the interstitium, epithelium and endothelium. Heterophils and macrophages appear to play important roles in tissue injury.     

Scanning electron microscopic studies on the red pulp of the mink spleen

In order to obtain three-dimensional information on the fine architecture of the red pulp of the mink spleen, especially the circulation pattern in the red pulp, perfusion-fixed and freeze-cracked specimens were examined with a scanning electron microscope. A latticework was formed by elongated endothelial cells (rod cells) with side processes and the spongy reticular tissue. The outer surface of the sinus was covered with fine processes of reticular cells. Numerous sheathed arteries were found in the splenic cord. The sheath was composed of a few layers of flat reticular cells. The arterial capillaries of the red pulp opened directly into the cordal space. No evidence could be detected to prove or suggest any direct continuity between arterial capillaries and splenic sinuses. These results strongly support the concept of "open circulation", at least in the red pulp of the mink spleen, with the possibility of a "functionally closed circulation" under some physiological conditions.     

Pathology of proliferative haemorrhagic enteropathy in pigs.

Examination of the small intestine of pigs with proliferative haemorrhagic enteropathy showed changes consistent with defects in vascular permeability. Early in the disease there were many eosinophils and distension of lacteals and intercellular spaces with proteinaceous material. Later the predominant features were red blood cells and exudate in tissue spaces. This was most severe and extensive at the tips of villi which were covered by a cast of cells and fibrinous exudate. Adenomatous intestinal mucosal cells contained organisms that were free within the apical cytoplasm and were morphologically identical with those seen in the related disease, porcine intestinal adenomatosis. Also these bacteria were seen free in the subepithelial mucosal area, in blood vessels and within membrane-bound vesicles in phagocytic cells in the mucosa and its blood vessels. Mast cells were prominent in some areas as were thrombosed vessels.     

Ultrastructural and Immunohistochemical Studies on Uptake and Distribution of FITC-Conjugated PLGA Nanoparticles Administered Intratracheally in Rats

Polylactide-glycolide (PLGA) nanoparticles have been developed as pulmonary drug delivery carriers. To investigate their behavior, small- (d50 = 74 nm) and large-sized (d50 = 250 nm) FITC-conjugated PLGA nanoparticles were intratracheally administered to rats and were traced for 5, 30 and 60 minutes and 24 hours after administration (HAT). Immunohistochemically, a, FITC-positive reaction was observed in type-I alveolar epithelial cells (type-I AEC), endothelial cells and alveolar macrophages in the lungs from 5 minutes after treatment (MAT) to 24 HAT in both nanoparticle groups. In the kidneys, a positive reaction was observed in proximal tubular epithelial cells at 30 MAT; the reaction peaked at 60 MAT and was reduced at 24 HAT, while no positive reaction was seen in other sites. Ultrascructurally, the number of membrane-bound vesicles, which were approximately 70 nm in size and hard to distinguish from pinocytic vesicles, apparently increased in type-I AEC and endothelial cells at 5 MAT in the small-sized group, in comparison with the control group receiving physiological saline. The number of vesicles in the large-sized group was almost same as that in the control group. On the other hand, in both nanoparticle groups, lysosomes filled with nanoparticles appeared in alveolar macrophages from 30 MAT to 24 HAT. These results indicate that PLGA nanoparticles might be quickly transferred from the alveolar space to the blood vessel via type-I alveolar epithelial cells and excreted into urine, and that there is a threshold for particle size, less than approximately 70 nm in diameter, with regard to absorption through the alveolar wall.     

Light and electron microscopic features of eperythrozoon-like parasites in a North American opossum (Didelphis virginiana).

Epierythrocytic parasites associated with a severe anemic episode have not been previously reported in the opossum. A Wright-Giemsa-stained peripheral blood smear from an anemic North American opossum (Didelphis virginiana) revealed numerous organisms attached to red blood cells either singularly or in chains. Ring forms of the organism were common and could be found free in the plasma. Electron microscopy revealed that these organisms were attached to the intact plasma membrane in depressions on the surface of red blood cells. Delicate fibrils between the organism and adjacent membrane were observed. The organisms were round to oval with a diameter of 300-750 nm and were enclosed by a single limiting membrane. The light and electron microscopic features of these epierythrocytic organisms are similar to those reported for Eperythrozoon and Haemobartonella species.     

Severe biliary hyperplasia associated with liver fluke infection in an adult alpaca

An adult alpaca (Lama pacos) had a locally extensive area of hepatic atrophy involving the right lobe. Grossly, the atrophic lobe was light tan and firm and contained small, raised, white to yellow, partially mineralized circular nodules predominantly at the periphery of the atrophic tissue. Microscopically, viable hepatocytes were not present in the atrophic area, and the tissue consisted of diffuse biliary epithelial proliferation without any evidence of nuclear or cellular atypia or the presence of mitotic figures. The circular mineralized nodules consisted of granulomatous inflammation with intralesional parasitic ova surrounded by fibrous connective tissue. Morphologically, the ova were compatible with those of Fasciola hepatica. The severe biliary hyperplasia was unusual, and it was not clear whether it was caused by an aberrant host response to the parasitic infection or whether it was an unrelated event.     

A morphological study of simple testicular cysts in the ostrich (Struthio camelus)

Simple testicular cysts are rare in mammals and of unknown aetiology, but dietary conditions have been implicated in this phenomenon in poultry. This study characterises the structural features of simple intratesticular cysts in the ostrich. Seven testes from a total of 15 sexually mature ostriches slaughtered during the breeding season were used. The testes contained multifocal, fluid-filled, unilocular cysts which were lined by a simple squamous or low cuboidal epithelium and surrounded by a thick layer of fibrous connective tissue. The cysts developed within seminiferous tubules and displayed morphological features similar to those reported in man and domestic poultry. The testis parenchyma revealed several foci composed of intermingled normal seminiferous tubules and variably sized intratesticular cysts. The atrophic tubules lay within a mass of hyperplastic, fibroblastic intertubular connective tissue in the proximity of large cysts and their formation appeared to result from hydrostatic pressure exerted by cysts. Morphological evidence supports a continuous process of cyst formation in the affected testis and a concomitant progressive loss of atrophic seminiferous tubules. A pathogenetic scenario of cyst formation and the effect of simple cysts on testicular histology has been proposed. Although the course of this phenomenon remains unknown, its impact on the fertility of this economically important bird deserves closer scrutiny.