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Biomedical subjects

R P Awadhiya

Publications and source records attributed to R P Awadhiya.

At least 19 recordsLinked to original sources
PubMed1992

Increased vascular permeability and leucocyte emigration in Escherichia coli endotoxin injury in the chicken skin.

The permeability response was examined in chickens following intradermal injection of Escherichia coli endotoxin. The 'dye' and 'colloidal carbon' techniques were employed. The endotoxin evoked a monophasic response of immediate-prolonged type. The increase in vascular permeability was confined to venules and small veins only, indicating its mediation by endogenous permeability factors. The carbon labelling exhibited arboreal, disjointed and rectangular to hexagonal patterns. Histologically, a striking feature of the reaction was an accumulation of basophils in unusually large numbers. No other type of stimulus appears to induce basophilic response of a similar magnitude in the chicken. The results suggest that endotoxin, being a bacterial product, may exert a chemotactic effect on basophils. Hyperaemia, oedema, necrosis and formation of perivascular lymphoid aggregates were also recognised.

Animals↗
PubMed1989

Erythrophagocytosis in phenylhydrazine induced acute anaemia in chickens.

Acute anaemia was experimentally induced in chickens with a single subcutaneous injection of phenylhydrazine-hydrochloride. The birds were necropsied at fixed intervals. Liver, spleen and red bone marrow (from middle of tibia) were promptly dissected out. Impression smears were stained and examined under dry high power. Erythrophagocytosis was massive in the liver, moderate in the spleen and less conspicuous in bone marrow. Extensive erythrophagocytosis by the mononuclear cells might be associated with extravascular haemolysis. This appeared to be a major factor in the induction of anaemia.

Acute Disease↗
PubMed1988

Quantitative estimation of increased vascular permeability in acute inflammatory reaction in the chicken skin.

An increase in vascular permeability was estimated quantitatively in acute inflammatory reaction in the chicken using passive cutaneous anaphylaxis as an experimental model. Dye exuded in the cutaneous lesion was extracted by formamide and measured spectrophotometrically. The technique, though time-consuming, worked well in the chicken. The results suggested that the method can be profitably utilised in studies relating to avian inflammation.

Animals↗
PubMed1988

Suppression by mepyramine maleate of the increased vascular permeability in passive cutaneous anaphylaxis in the chicken.

Passive cutaneous anaphylaxis was produced in chickens pretreated with the antihistamine mepyramine maleate. Quantitative estimation of the increased vascular permeability in the lesion revealed 79.5% suppression indicating its mediation largely by histamine. The findings suggest that the quantitative estimation of the increased vascular permeability, though time-consuming, is more precise than the visual assessment.

Aminopyridines↗
PubMed1988

A microscopic study of increased vascular permeability and leucocyte emigration in passive cutaneous anaphylaxis in the chicken.

Passive cutaneous anaphylaxis was produced in chickens with bovine serum albumin (BSA) and anti-BSA chicken serum. Colloidal carbon was then given intravenously to identify the leaky vessels. Examination of the resulting sequential changes revealed a marked increase in vascular permeability affecting the venules. A noteworthy feature of the reaction was the early participation of the basophils, which contained phagocytosed carbon particles. Eosinophils were absent.

Animals↗
PubMed1987

A topographical study of increased vascular permeability in passive cutaneous anaphylaxis in the chicken.

Passive cutaneous anaphylaxis was produced in chickens with bovine serum albumin (BSA) and anti-BSA chicken serum. Colloidal carbon was then given intravenously to identify the leaky vessels. Microscopic examination of cleared unstained skin revealed the topography of labelled vessels. The carbon labelling was confined to venules and small veins only. Examination of the time-course of permeability response revealed a biphasic pattern.

Animals↗
PubMed1987

Attempted induction of local Shwartzman reaction in the chicken.

Chickens and rabbits were injected intradermally with an endotoxin, namely Escherichia coli lipopolysaccharide (LPS). Twenty-four hours later, LPS was again administered intravenously to induce a local Shwartzman reaction. A typical cutaneous inflammatory reaction developed in rabbits, but not in chickens. Even very high doses of LPS, that made the birds visibly sick, failed to elicit the reaction. The results suggest that chickens are refractory to the Shwartzman reaction. A noteworthy feature of the chickens' response to intradermal endotoxin was the formation of prominent perivascular lymphoid aggregates.

Animals↗
PubMed1987

Pathology of concanavalin A-induced cutaneous reaction in the chicken.

Sequential study of permeability and cellular responses following intradermal concanavalin A in the chicken skin, using the colloidal carbon technique, revealed an increase in vascular permeability which was mostly confined to venules. A noteworthy feature of the reaction was marked accumulation of basophils, even in the later stages, and the early appearance of perivascular lymphoid aggregations. The occurrence of well formed giant cells, hypertrophy and hyperplasia of vascular endothelium and marked acanthosis of the epidermis were the other prominent changes. The findings suggest that Con A, in the chicken, appears to have a more general effect on the different types of cells and that it may act as a mitogen not only for T lymphocytes but also for endothelial and epithelial cells.

Animals↗
PubMed1982

Studies on acute inflammation in the chicken using turpentine-induced pleuroperitonitis as a test system.

An acute inflammatory reaction was induced in chickens by intraperitoneal injection of turpentine. The birds were then killed at various intervals and the peritoneal exudate sampled. The antihistamine mepyramine maleate was administered to another group of birds and the procedure repeated. Following turpentine injections there was a biphasic increase in vascular permeability, the early phase apparently mediated by histamine.

Animals↗
PubMed1981

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.

Animals↗
PubMed1980

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.

Animals↗
PubMed1980

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.

Animals↗
PubMed1980

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.

Animals↗