Experimental coronary vein obstruction in sheep: changes in haematological and inflammatory markers

It has been suggested that obstruction of coronary veins can induce myocardial infarction similar to coronary artery obstruction. In this study, the coronary veins of the sheep heart were blocked experimentally and haematological and inflammatory indices (haptoglobin, serum amyloid A, tumour necrosis factor-α and interferon-γ) alterations were studied. Twenty sheep were used for this study. Anaesthesia was induced by ketamine and maintained using halothane. The intercostal space between ribs 4 and 5 was incised, the thorax was opened and the pericardium was incised. In the control group (1), only the myocardium was manipulated. In the second group, three to four superficial coronary veins were totally ligated. In the third group, three to four superficial coronary veins were partially ligated. In the fourth group, five to ten superficial coronary veins were totally ligated. In the fifth group, five to ten superficial coronary veins were subtotally ligated. Then, the intercostal space was sutured. Post-operative care included clinical evaluation, antibiotic therapy, anti-inflammatory drugs and collection of jugular vein blood for haematological and inflammatory index evaluation on days 0, 1, 2, 3, 4, 5, 8, 12, 15, 25 and 35 post-operatively. Red blood cell count, haematocrit and haemoglobin concentrations were similar in all groups. The leukocyte count following an operative procedure initially showed an increase, followed by a reduction back to normal values, in all groups. The increase in the first 5–7?days was significant. The differential leukocyte count in all groups increased initially and then reduced to normal values. Inflammatory index parameters, including acute phase proteins and inflammatory mediators, initially increased and then decreased in all groups after surgery. Healing in damaged tissues and physiological adaptation to the experimental cardiac condition caused a decrease in inflammatory parameters. No significant difference between groups was seen in the inflammatory parameters (P?>?0.05) because of the same condition of inflammation due to the surgery and cardiac necrosis, regardless of the outcome.     

Inactivation and morphological changes of avian influenza virus by copper ions

The infectivity of the H9N2 virus to MDCK cells was time-dependently inhibited by Cu(2+) at concentrations of 2.5-250 microM. In 25 microM Cu(2+) solution, the virus titer decreased by approximately 3 and 4 log within 3 and 6 h, respectively. Compared to Cu(2+), Zn(2+) was much less effective in virus inactivation. The H9N2 virus hemagglutinin activity was not affected by 2.5-250 microM Cu(2+). The H9N2 virus neuraminidase (NA) activity was drastically reduced by 25 mM Cu(2+), marginally reduced by 250 microM Cu(2+), and not affected by 25 microM Cu(2+). Thus, we found that copper ions suppress the infectivity of influenza virus at lower concentrations at which neither NA nor hemagglutination inhibition occurs. Electron microscopic analysis revealed morphological abnormalities of the Cu(2+)-treated H9N2 virus. Additional studies should be undertaken to clarify the mechanism underlying the antiviral effect of copper ions on influenza virus.     

Cutaneous haemangiosarcoma in a sheep: morphological,histopathological and immunohistochemical observations

Haemangiosarcomas of animals are reported mainly in the dog and cat and less commonly in the cow, horse, pig and goat, but no cases have been reported in sheep. These tumours occur more commonly in internal sites than in the subcutis. A large mass in the right flank of a 6-year-old Sardinian sheep showed histopathological features of a haemangiosarcoma. The antibodies anti-Factor VIII-related antigen (FVIII-RAg) and anti-CD31 did not react immunohistochemically with either the normal or the neoplastic endothelial cells, whereas endothelin-1 strongly labelled both the normal and the neoplastic cells at different stages of differentiation. The results emphasize the usefulness of endothelin-1 as a vascular marker in sheep, particularly in the immunohistochemical detection of neoplastic endothelial cells.     

Sporidesmin toxicity in rabbits: biochemical and morphological changes

The earliest lesion in rabbits dosed orally with 2 mg of sporidesmin per kg of body weight was necrosis of occasional hepatocytes 1 day after dosing. The most consistent lesion was a severe necrotizing cholangitis of medium and large-sized intrahepatic and extrahepatic bile ducts, first seen 2 days after dosing. Similar lesions were also present in the gall bladder of some rabbits. Expansion of portal triads with fibrous tissue and proliferating bile ductules progressed to pseudo-lobulation by 21 days. Other hepatic changes observed irregularly included large infarcts at the periphery of some lobes, and multiple small foci of coagulation necrosis in midzonal and periportal regions. Vascular necrosis and thrombosis, invariably adjacent to necrotic bile ducts, was presumably responsible for the hepatic necrosis. Serum cholesterol and total bilirubin concentrations and GGT activity reached peaks 15 days after dosing and were useful indicators of the severity of biliary lesions. Serum ID activity was the most useful indicator of hepatic necrosis following oral dosing with sporidesmin. The similarity between hepatobiliary lesions observed in sheep and rabbits with experimental sporidesmin toxicity suggests that the rabbit would be a useful model for studying methods of treatment and prevention of "facial eczema" in ruminants.     

Experimental acute selenium intoxication in lambs

The toxic effects of 5 mg per kg body weight of selenium given as sodium selenite orally or parenterally to growing lambs were examined. There was considerable individual variation in both susceptibility to intoxication and the degree of pathological change displayed. The results affirm the previously reported deleterious effects on the cardiovascular, respiratory and urinary systems and highlight damage to secondary lymphoid tissue in various organs. The use of a histochemical method for detecting selenium bonds demonstrated correlation between the density of reaction-product and histopathological changes within tissues, and showed the distribution of selenium in other tissues in which the gross and histopathological findings were non-specific or minimal.     

Aging of liver: morphological and biochemical changes

Light-microscopically there are no significant age-dependent changes in the liver, due to the slight increase in biochemically determined connective tissue components. Electron-microscopical comparison of young and old animals show a larger size and decreased numbers of liver cell mitochondria in older animals. Collagen synthesis in liver is accelerated during growth, as demonstrated by assay of the [3H] proline incorporation rates and of the specific activity of hydroxyproline, corresponding to a decrease in the prolyl hydroxylase activity with age. The neutral salt-soluble collagen fraction may be regarded as a parameter for collagen synthesis, which is activated during the growth period and then remains constant without age and sex differences. Not much is known about the significance of these changes with increasing age or about their initiating factors, although there are parallel findings for liver intoxication and inflammation.     

Heterogeneous visceral nerve changes in acrylamide intoxication

Summary A variety of visceral nerves were studied by intermediate filament immunocytochemistry in rats intoxicated with acrylamide. In such animals, oesophageal and diaphragmatic motor end-plates were invaded and deformed by neurofilament protein-like material, while afferent fibres of diaphragmatic neuromuscular spindles and myelinated sensory fibres of the iris showed striking terminal accumulation of similar material. Conversely, the rich population of thin afferent fibres of the iris showed no obvious abnormality, while pre-terminal changes were seen along the extrinsic nerve fibres supplying the cornea and myenteric ganglia. Multiple lesions were demonstrated in gut nerves of acrylamide-treated rats, while scattered enteric glial cells showed abnormally coarse morphology and a striking increase in glial fibrillary acidic protein immunoreactivity. A distinct, delicately varicose appearence was revealed by neurofilament protein-immunostaining in bladder nerve fibres of normal rats, which was changed to one of coarse dilations by acrylamide. In conclusion, apparently selective changes were found along different types of axons, in dicating marked heterogeneity in cytoskeletal organisation among visceral nerves. Taken together with the proposed inhibition by acrylamide of neurofilament proteins degradation, the above findings may suggest a non-uniform distribution of neurofilament degradation sites along distal regions of different axons.     

Blood copper and serum enzyme changes following copper calcium E.D.T.A. administration to hill sheep of low copper status

Changes in blood copper and serum enzyme levels following copper calcium complex of ethylene diamine tetra acetic acid administration were studied in ewes in 3 hill flocks of low copper status and with a history of swayback. Blood copper levels increased within a few hours of injection in all the sheep and in some animals from 2 flocks there was a release of liver-specific enzymes into the blood 24 to 48 hours after dosing. Three animals died within 36 hours of injection.     

Experimental cadmium poisoning in sheep

Pathomorphological investigations of internal organs were made in sheep given sublethal doses of cadmium. Early histological damages in kidneys were established by renal biopsy in some experimental animals. The main histological changes were characterized by granular degeneration in proximal tubules and glomerular endothelial proliferation in kidneys, granular degeneration in hepatocytes, pericapillary oedema and activation of capillary endothelium and Kupffer cells in liver, oedematous and degenerative changes in cerebrum and in the region of Purkinje cells of cerebellum, hyperplasia and proliferation of alveolar epithelium and perivascular or peribronchial mononuclear cell infiltration in lung, and degenerative changes in the medulla and zona glomerulosa of adrenal glands.     

Molybdenum toxicity in sheep: Epiphysiolysis,exotoses and biochemical changes

Fifteen sheep were allowed to graze pasture that had been sprayed three times with molybdenum at the rate of 420 g per hectare. Shortly after lameness was observed in 2 of the sheep, all were killed and necropsied. In 8 animals there were exostoses and haemorrhages about the long-bones, and in 2 other sheep the great trochanters of the femurs were loosened. The lesions appeared to be due to defects in the connective tissue at points where muscle is inserted into bone and to defects in the epiphysial plates of the trochanters. No similar lesions were found in 15 control sheep grazing unsprayed pasture. During the course of the experiment the molybdenum concentration of the plasma of the experimental sheep increased above that of control sheep. Experimental sheep had a greater proportion of plasma copper that was insoluble in trichloroacetic acid than control sheep. Amounts of copper in the liver of experimental animals were reduced, but copper in the periosteum was increased compared with controls.