Enteropathogenicity of Treponema hyodysenteriae in young chicks.

Observation by scanning electron microscopy served to demonstrate that Treponema hyodysenteriae colonized the cecal mucosa of young chicks on day 3 after inoculation and produced lesions from 9 days after inoculation. Severe and clearly visible lesions were present on the cecal mucosa of all chicks necropsied 18, 21, and 24 days after inoculation. Severe lesions such as roughness of mucosal surface and disappearance of the mucosal foldings were observed at low magnification. The lesions were characterized by a destruction of superficial epithelial cells and dilation of crypt orifices. The dilated orifices of crypts were clearly observed, and the number of the crypts increased as compared with that of the crypts on the cecal surface in non-infected chicks. At high magnification, mucosal epithelial cells were found to be desquamated and the surface of the lamina propria mucosae had appeared. Numerous treponemas became visible on the surface of damaged epithelial cells and on the surface of the lamina propria mucosae.

Investigations into the location of Treponema hyodysenteriae in the cecum of experimentally infected young broiler chicks by light- and electronmicroscopy.

Numerous Treponema hyodysenteriae were present both on the mucosal surface and in the deep crypts of the cecum of young broiler chicks 7 and 14 days after inoculation with the treponemes. The treponemes in the ceca of chicks inoculated with 10(8) cells were observed more frequently than those of chicks inoculated with 10(7) cells. The treponemes in the ceca were observed by light microscopy, scanning electron microscopy and transmission electron microscopy. The lesions were primarily confined to the cecum. Desquamation of epithelial cells, edema, leukocytic infiltration and hemorrhage were observed in the mucosae.

Perivascular eosinophilic droplets in swine brain induced by Escherichia coli toxin.

Pigs inoculated intravenously with the culture supernatant and extract of Escherichia coli were investigated histologically. Perivascular eosinophilic droplets and slight vascular degeneration were observed in the medulla oblongata, mid-brain and pons. These droplets were negative for periodic acid-Schiff staining.

Experimental infection of young broiler chicks with Treponema hyodysenteriae.

In young broiler chicks which were inoculated with 10(8) cells of Treponema hyodysenteriae within 24 hr after hatching, numerous treponemes were observed by scanning electron microscopy on the surface of the cecal mucosa 7 and 14 days after the inoculation. However, in the groups inoculated with 10(7) cells, treponemes were not observed on the cecal mucosa 14 days after the inoculation, and the isolation rate from the cecal contents was lower than that from cecal contents of chicks inoculated with 10(8) cells. While the cecal mucosa of noninfected chicks had a smooth surface, that of the chicks infected with treponemes was generally roughened and the epithelium was eroded. Numerous treponemes were also observed within the eroded epithelium.

Light and electron microscopic observations on granulomatous lesions in pigs dosed with Mycobacterium intracellulare.

The histology and ultrastructure of the granulomatous lesions were studied in 18 pigs dosed orally with Mycobacterium intracellulare serotype 8. The pigs were killed 2, 4, 6, 8 and 12 weeks after dosing. Histologically, initial granulomatous lesions were seen in the tonsils 6 and 8 weeks after dosing. Initial or more advanced granulomatous lesions were observed in the tonsils and lymph nodes (mandibular, jejunal, ileocolic and superficial inguinal) 12 weeks after dosing. The initial granulomatous lesions appeared as slight proliferations of epithelioid cells and multinucleated giant cells. Advanced granulomatous lesions were nodular proliferations of epithelioid cells and multinucleated giant cells (epithelioid-cell nodule). In more advanced granulomatous lesions, the epithelioid-cell nodules increased in size and showed caseation necrosis, calcification and fibrosis. Ultrastructural examination revealed that the epithelioid-cell nodules consisted of mononuclear cells, epithelioid cells and multinucleated giant cells. In the caseous foci of the epithelioid-cell nodules, an electron-dense amorphous material with collagen fibres was deposited in the intercellular spaces. Although a small number of acid-fast organisms were observed histologically, they could not be detected ultrastructurally. The histological and ultrastructural findings of the present cases are compared with those of pigs infected with M. avium and with human lesions of tuberculosis and sarcoidosis.

Swine cerebrospinal angiopathy and demyelination and malacia.

In 15 pigs affected with cerebrospinal angiopathy accompanied by demyelination and malacia, the main symptoms were diarrhea and subsequent circling, spasms, sudden forward movements, ataxia, and inability to hold the head straight. Escherichia coli was isolated in a pure culture from the small intestine of pigs with diarrhea. The only gross change was a slight increase in cerebrospinal fluid. Histologic examination showed vascular lesions, demyelination, and malacia, most commonly located in the medulla oblongata, pons, and midbrain. The vascular lesions were degenerative and there were necrotic changes of the vessel walls and formation of periodic acid-Schiff positive perivascular eosinophilic droplets. Ultrastructurally, the swollen astrocytes around the vessels had many osmiophilic bodies in their cytoplasm with no limiting membrane. Demyelination and malacia, as well as vascular lesions, were considered to be the characteristic changes of cerebrospinal angiopathy. Our study suggests that E. coli may be a cause of cerebrospinal angiopathy.

Morphologic evidence of the histogenesis of epithelial thymoma in a cow.

Light and electron microscopic studies were performed on an epithelial thymoma obtained from a cow. Tumor masses were found in the cervical and dorsal mediastinal portions, in the hilus and parenchyma of the lung, on the surface of the kidney, and in a uterine horn. The masses were encapsulated and divided into distinct lobules or nodules by prominent trabeculae. Examination of the tumor cells by light microscopy showed squamous epithelial characteristics in both the eosinophilic granules and the periodic acid-Schiff-positive granules. Electron microscopic observations revealed that the tumor cells had intercellular microvilli, which appeared to be the interdigitations between the cells, tonofilaments, and desmosomes. A few of the tumor cells contained round vesicles which resembled the hypertrophic type of epithelial cells of a normal thymus. These findings indicated that the tumor originated in the thymus' epithelial cells.

Clinico-biochemical studies on fattening cattle with stiff gait as main symptom in Japan.

The chemical compositions of blood and bone were estimated in eight affected cattle as part of clinico-biochemical studies on a disease of beef cattle for fattening with stiff gait of the four limbs, strange posture, and elongation and deformation of the hoofs as main symptoms. Eight of the affected cattle were divided into two groups from the results of some examinations. Radiographical changes, such as the deformation, atrophy and lack of the apex of the third phalanx, were remarkable in five affected cattle (Nos. 1, 2, 4, 5 and 6; group A), but not so remarkable in three (Nos. 7, 8 and 9: group B). The blood composition was within a normal range in group A. On the other hand, total serum protein, urea nitrogen, calcium and inorganic phosphorus were a little lower and magnesium and potassium higher in blood level in group B than in control cattle. The pH of rumen juice was within a range of 6.0 to 6.5 in all the effected cattle. The differences of components of phalanges were remarkable between the two groups. Namely, in group A, the magnesium and sodium levels of phalanges were higher than in control cattle. Ash and calcium contents increased distinctly at the tip of the third phalanges were higher than in control cattle. On the other hand, in group B, ash, calcium, sodium and potassium contents were lower than in control cattle. The fat content was much higher in the affected groups than in the control group. There wer slight changes in the inorganic component levels of the ungual layer. These changes were proportional to those of the phalanges.

Pathological changes of xanthinurolithiasis in calves.

Pathological examination was carried out on a male and a female beef calf 3 months old involved in an outbreak of xanthinurolithiasis. This outbreak has been found among indigenous Japanese Black calves in an area of the Kyushu region since 1971. Involved in it, calves were retarded in growth, with the back curved, exhibiting depression and anorexia. A characteristic gross change was the accumulation of yellowish white or yellowish brown sand-grain-like calculi in the urinary passage. Histologically, a number of calculi, as birefractive crystals, were contained mainly in the collecting and distal uriniferous tubules in the renal medulla. In the uriniferous tubules epithelial cells surrounding those crystals presented such reaction as to form syncytia, and the surrounding connective tissue proliferated. Biochemical examination revealed that the calculi were composed of xanthine.

Pathological changes of experimental polychlorinated biphenyl poisoning in chickens.

Two experiments were carried out to study pathological changes of polychlorinated biphenyl (PCB) "KC 400" poisoning. In them chickens were administered with this agent for a relatively short time. Eleven experimental diets were prepared to contain 11 different PCB concentrations, 4,800 ppm being the highest, respectively. They were given to broiler chickens in initial feeding and later. All the chickens fed 300 ppm and higher concentrations of PCB died, showing the serious dilatation of uriniferous tubules and involution of the bursa of Fabricius, by the time when they reached 12 days of age. All the chickens, except a very few, fed 100 ppm remained alive at the end of the experimental period, when they were 41 days of age and exhibited such edematous changes as hydropericardium. Few chickens fed 50 ppm and less manifested pathological changes until the end of the experimental period, when they were 22 days of age. Two experimental diets were prepared to contain 600 and 200 ppm of PCB, respectively. They were given to layer chickens in initial feeding and later. These layers were sacrificed for autopsy every fourth day. A gain in body weight was retarded mostly in those fed 600 ppm. Dilatation of uriniferous tubules and involution of the bursa of Fabricius began in the very early stage of experimental feeding in both groups. Hydropericardium occurred to many of the chickens fed 200 ppm in the late stage of the experimental period. The results of both experiments indicated that there was no essential difference in changes of PCB poisoning between broiler and layer chickens. The principal changes of the poisoning were dilatation of uriniferous tubules, involution of the bursa of Fabricius, and edematous alterations. They appeared in a relatively early stage of the experimental period of PCB feeding. Their severity was strongly dependent upon the concentration of PCB contained in the diet.

Behavior of a vigorous alpha- or beta-hemolysin-producing strain of Staphylococcus aureus in the cutaneous tissue of mice.

Two strains of Staphylococcus aureus were examined for behavior in the cutaneous tissue of mice by the fluorescent antibody technique, hematoxylin and eosin staining. When about 10(8) viable cells of an alpha-hemolysin-producing strain (Wood 46) were inoculated subcutaneously into a mouse, they multiplied in the subcutaneous tissue of the mouse and gradually entered the corium to produce alpha-hemolysin and nuclease. Edematous and necrotic lesions were observed in the cutaneous tissue where the organisms had multiplied. When 10(8) viable cells of a beta-hemolysin-producing strain (Kitami 3-9D) were inoculated into a mouse, they multiplied within a narrow extent surrounded mainly by infiltrating leukocytes and produced mainly beta-hemolysin. The changes of cutaneous tissue were weaker in mice inoculated with Kitami 3-9D strain than in mice inoculated with strain Wood 46. When 10(6) viable cells of both strains were inoculated into mice, they were phagocytized by leukocytes. Neither multiplication of organisms nor production of any active extracellular substance was observed in these mice. Edema, degeneration, and necrosis were also noticed in the cutaneous tissue of mice inoculated with alpha- and beta-hemolysin. In addition, the infiltration of leukocytes was inhibited mainly by alpha-hemolysin.