Haematological changes in buffalo calves inoculated with Escherichia coli endotoxin and corticosteroids.

Haematological studies were conducted on 10 clinically normal water buffalo calves to determine leucocytic responses to Escherichia coli endotoxin, prednisolone and dexamethasone. Intravenous injection of 10 micrograms endotoxin induced minimal decreases in leucocyte numbers, whereas 20, 50 and 100 micrograms produced a marked leucopenia within one hour. Moderate to marked leucopenia, neutropenia and lymphopenia persisted for three to 14 hours. Significant rebound neutrophilia was evident at six to eight hours after inoculation in calves given only 10 and 20 micrograms. Intramuscular injection of prednisolone (100 mg) and dexamethasone (5 mg) produced increases in total leucocyte counts and neutrophil numbers within two hours. Moderate to marked leucocytosis and neutrophilia persisted for eight to 24 hours. Lymphocyte response was unlike that in other species in that lymphopenia was not a consistent feature of the corticosteroid response. A transient monocytosis was seen following administration of prednisolone but not of dexamethasone, while eosinopenia and basopenia developed in both cases. In conclusion, endotoxin and corticosteroid induced changes in total and differential leucocyte counts in water buffalo were largely similar to those seen in cattle.

Pathology of reversed passive Arthus reaction in the chicken.

Sequential study of gross and microscopic changes in the chicken skin revealed that it was possible to induce a reversed passive Arthus reaction in 14- to 20-week-old chickens, using bovine serum albumin and anti-bovine serum albumin. However, high doses of immune reactants were required to elicit lesions of optimal intensity. The lesions were characterised by erythema, oedema, and the formation of thrombi in the vessels of the superficial dermis. Thrombosis, caused by the adherence of thrombocytes to vascular endothelium, induced widespread necrosis and haemorrhage. The inflammatory changes, which were confined to the deep dermis, included a necrotising vasculitis with infiltration of heterophils, monocytes and basophils. Phagocytosis of carbon particles by heterophils and basophils appeared to be sensitisation-dependent. The reaction was also characterised by the development of perivascular lymphoid foci. The findings indicate that in chickens the thrombocyte appears to be the principal cell involved in the induction of tissue damage.

Pathology of the active Arthus reaction in the chicken.

It was possible to produce an active Arthus reaction in chicken skin which resulted in gross and microscopic lesions. Histologically, the reaction was predominantly thrombotic in nature and restricted to the upper dermis. The thrombi appeared to develop as a consequence of immune complex deposition with adherence and aggregation of thrombocytes at the vascular endothelium. Thrombosis induced widespread necrosis and haemorrhage and vasculitis occurred in the lower dermis. Up to four hours after inoculation, the cell population comprised an infiltration of heterophils, monocytes and basophils, suggesting an immediate hypersensitivity reaction. This was followed by an Arthus type reaction for four to 12 hours involving both heterophils and monocytes. A characteristic feature was the development of early perivascular lymphoid foci. After 12 hours the reaction resembled a delayed hypersensitivity. The use of colloidal carbon suggested that whereas phagocytic activity of the heterophils and basophils appeared sensitisation dependent, that of thrombocytes and monocytes was independent of it. The findings indicate that in the Arthus reaction in the chicken the thrombocyte appears to be the principal cell producing tissue damage by thrombosis. A comparison was made with the active Arthus reaction in the rabbit.

Demonstration of the phagocytic activity of chicken basophils in the reversed Arthus reaction using colloidal carbon.

Chicken basophils showed phagocytosis of carbon particles in reversed passive Arthus reaction, induced in the skin. Heterophils, monocytes and thrombocytes also contained carbon particles, but eosinophils revealed them only occasionally. The findings suggest that basophils may share phagocytic properties with other cells under immunological stimulus.

Eosinophil leukocytic response in dinitrochlorobenzene skin hypersensitivity reaction in the chicken.

The cutaneous inflammation evoked by topical application of dinitrochlorobenzene in sensitised chickens was studied at 24- and 48-hours post-challenge. A slight increase in vascular permeability was present at 24 hours but absent at 48 hours. Histologically, the reaction comprised oedema and a diffuse infiltration of polymorphonuclear granulocytes in the superficial dermis, and intense perivascular mononuclear infiltrations in the deep dermis. The apparent participation of eosinophils was a noteworthy feature of the reaction.

Microscopic study of increased vascular permeability and leucocyte emigration in the chicken wing web.

The components of an acute inflammatory response in the chicken were investigated using a combination of histological and colloidal carbon techniques. The experimental model was the inflammatory reaction induced by the subcutaneous injection of turpentine or carrageenin into the wing web. Increased vascular permeability was shown to be mainly venular in origin. There did not appear to be an ordered migration of heterophils and monocytes and the process was unrelated to altered vascular permeability. Special features distinct from acute mammalian inflammation included a basophilic response, giant cell formation and the development of perivascular lymphoid foci.

A microscopic study of increased vascular permeability and leucocyte emigration in thermal injury in the chicken skin.

Microscopic study of the acute inflammatory reaction following thermal injury in the chicken skin, using the colloidal carbon technique, revealed an increase in vascular permeability both in capillaries and venules. The capillary response was of a shorter duration than the venular response which was prolonged. Venular leakage seemed to play the major role in oedema formation. Concurrent emigration of heterophils and monocytes, and participation of basophil leucocytes in the early stages appeared to be the contrasting features from mammalian inflammation.

Studies on acute inflammation in the chicken using mesentery as a test system.

An acute inflammatory response was produced in the chicken by the intraperitoneal injection of turpentine and vascular permeability was assessed by the technique of carbon labelling. This revealed a biphasic pattern of increased permeability which comprised an immediate transient reaction and a delayed more prolonged response. In both phases, the increased permeability remained confined to venules only. The vascular permeability was dissociated in time from leucocyte emigration. The pattern of leucocyte emigration revealed that heterophils and monocytes emigrated concurrently. Participation of basophils in significant numbers in the early stages indicated their possible role in avian inflammation. Examination of mast cells revealed morphological changes of degranulation and disruption. There was a coincident reduction in the population of these cells. It was thought likely that vasoactive amines released from the degranulated mast cells and the basophils might initiate the early vascular changes by acting on the venules.

A topographical study of increased vascular permeability in acute inflammatory reaction in the chicken skin.

An inflammatory reaction was produced in the skin of the chicken by various stimuli. Then the colloidal carbon technique was used to identify vessels showing an increased permeability. The type of vessel affected, the extent and duration of reaction after each procedure were compared. Intradermal histamine, 5-hydroxytryptamine and bradykinin caused extensive but transient carbon labelling which was confined to venules. Topical application of xylol produced a more persistent delineation of venules. Intradermal turpentine and carrageenin affected extensive and restricted portions, respectively, of venules, and to a lesser extent capillaries. Following thermal injury of 65 degrees C for 30 sec, the superficial capillary network was initially involved but the venular response persisted for up to 18 h. These findings are compared and contrasted with those reported in laboratory animals. The possibility of distinction between direct vascular injury and chemical mediation is discussed.

Demonstration of the phagocytic activity of chicken thrombocytes using colloidal carbon.

Chicken thrombocytes showed marked phagocytosis of carbon particles in both in vivo and in vitro systems. Initially, in both systems, thrombocytes containing carbon particles tended to form clumps. In the later stages, however, clumping was less obvious in the in vivo system. In addition to the thrombocytes, monocytes also contained carbon particles but heterophils did not. The present findings suggest that thrombocytes play a useful role in helping to clear the blood of foreign materials.

Dissecting aneurysm and cardiac tamponade.

A Gir cow which died suddenly had a dissecting aortic aneurysm. Death was caused by cardiac tamponade which followed rupture of the intrapericardial aorta after it had been damaged by onchocercosis.

Traumatic ventriculitis in chickens.

Nine cases of traumatic ventriculitis in chickens, with associated complications, are reported. The findings suggest that chickens with traumatic ventriculitis may die either from extreme emaciation or from toxemia.