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Biomedical subjects

G W Morgan

Publications and source records attributed to G W Morgan.

At least 55 records · Page 3Linked to original sources
PubMed1981

Hemagglutinin responses in Japanese quail treated with exogenous adrenocorticotrophin.

Injections of exogenous ACTH in chickens are known to cause immunosuppression provided that ACTH administration is properly timed with respect to immunization. In random-bred Japanese quail, injections of ACTH at various times both before and after immunization with erythrocyte antigens did not significantly alter antibody responses. This finding was consistent whether the ACTH was administered over a 4 hr or a 6 day period, and whether sheep or chukar erythrocytes were used as the antigen.

Adrenocorticotropic Hormone↗
PubMed1981

Humoral immunity in Japanese quail following surgical bursectomy at various ages.

Four separate experiments were conducted to determine the effects of surgical bursectomy (BSX) at periodic intervals on subsequent antibody production in Japanese quail. At 0, 1, 3, 7, and 28 days of age, BSX resulted in graduated increments in humoral immune responsiveness. Quail BSX at 0 and 1 day of age exhibited significantly reduced primary hemagglutinin responses, as well as reduced mercaptoethanol resistant (IgG) antibody levels. The production of mercaptoethanol sensitive antibody (IgM) levels were affected to a lesser degree in BSX quail than in controls. At 7 and 28 days of age, BSX resulted in no significant effects. At 3 days of age, BSX resulted in an intermediate effect with minimal reduction in antibody levels. Secondary antibody responses were reduced to a lesser extent than the primary responses. At 0 day, BSX reduced hemagglutinin and mercaptoethanol sensitive antibody levels during the early stages of the secondary responses. At other times, however, BSX did not affect secondary antibody responses.

Age Factors↗
PubMed1980

Effect of mercury toxicity on serum osmolality, plasma sodium and potassium, and serum proteins in the chicken.

Juvenile male chickens were exposed continuously to 300 micrograms/ml of mercury (Hg) in the form of mercuric chloride (HgCl2), via the drinking water, from hatching through six weeks of age. Serum osmolality and plasma potassium were increased significantly as a result of the Hg treatment. Plasma sodium was increased numerically in two of the three trials. Of the serum proteins, only albumin and the transferrins exhibited a consistent significant increase. It is concluded that alterations in serum ions and proteins account for the significant increase in plasma osmolality. The increase in transferrins may represent a mechanism to bind and detoxify Hg.

Animals↗
PubMed1980

Haemonchus contortus resistance in straightbred and crossbred Barbados Blackbelly sheep.

Resistance to Haemonchus contortus infection was studied in two experiments conducted with 52 lambs of widely different genetic background. Breed groups compared were: Dorset (D), Barbados Blackbelly (B), Dorset x Blackbelly (D x B), Suffolk x Blackbelly (S x B), Suffolk x Dorset x Blackbelly (S x D x B,[1/4 B]) and nonBlackbelly (NB, D and S). In each experiment, lambs were raised on concrete from birth and were essentially parasite free until infective larvae were administered. In Exp. 1, D x B, S x D x B and D wether lambs approximately 3 months old were infected with a standard dose of invective larvae estimated to be 98% H. contortus. D x B lambs had a longer (P < .05) prepatency period and, at necropsy 17-day postinfection, had a higher (P < .05) percentage of female parasites classified as immature than did the other breed groups. These data showed that the development of H. contortus larvae was inhibited in D x B host animals. In Exp. 2, B, D x B, S x B and NB ewe and wether lambs approximately 4 months old were treated with three sensitizing doses of H. contortus larvae. These were followed by a challenge infection. On the basis of fecal egg counts (eggs per gram feces, EPG), there was no evidence that the challenge infection induced a self-cure reaction in any breed group. All lambs with B breeding had significantly higher Hb levels at the end of the experiment than did NB lambs. b and S x B lambs had higher (P < .05) Hb levels than the D x B lambs, and B lambs had the highest (P < .05) mean corpuscular hemoglobin concentrations. Five days after the challenge infection, B, D x B and S x B lambs also had significantly higher white blood cell levels than did NB lambs. Significant sex differences were also observed in Exp. 2. Ewe lambs had lower final EPG levels, higher preinfection and postinfection Hb levels and higher maximum postinfection cosinophil levels. Breed x sex interactions for these parameters were not significant.

Abomasum↗
PubMed1980

Physiological effects of exogenous adrenocorticotropin injections in Japanese quail.

Administration of exogenous adrenocorticotropin (ACTH) into young Japanese quail resulted in certain physiological changes consistent with those which have been reported in chickens. These include reduced body weight gains and bursa weights. Also adrenal cholesterol values were decreased, and serum cholesterol and plasma refractive indices were increased. However, spleen weights, right adrenal weights, and packed cell volumes were not consistently altered at 24 hr post-ACTH administration. Collectively, these findings suggest that Japanese quail are less responsive to ACTH-induced adrenal hyperfunction than chickens.

Adrenal Glands↗
PubMed1977

Antibody responses to xenogeneic red blood cell challenge in the Japanese quail.

Previous reports indicate that Japanese quail are hyporesponsive to such conventionally used antigens as sheep red blood cells and bovine serum albumin. In this study the immune responsiveness of Japanese quail to several erythrocyte antigens was investigated. The quail produced higher antibody titers when immunized with chukar red blood cells than when immunized with sheep, turkey, or pheasant red blood cells. It is concluded that Japanese quail are capable of producing HA titers comparable in magnitude to those demonstrated by other laboratory animals, when the quail are immunized with an appropriate antigen. Chukar red blood cells are such an antigen.

Animals↗
PubMed1977

Immunosuppression in chickens by passive transfer of preparations of specific immunoglobulins.

The immunosuppressive effects of passive transfers of specific immunoglobulin preparations obtained from immune or hyperimmune sera were evaluated in chickens which were challenged with sheep red blood cells. The data indicate that IgY, fractionated from immune sera, and IgY and IgM, fractionated from hyperimmune sera, when passively administered at the doses employed in this study resulted in antibody-mediated suppression.

Animals↗
PubMed1976

Reduced symptoms of anaphylaxis in chickens by ACTH or heat.

Exogenous ACTH, when administered intramuscularly in four equal doses of 2 I.U./100 gm. of body weight at 24, 23, 22, and 21 hours prior to challenge with BSA, reduced the severity of anaphylaxis in BSA sensitized juvenile chickens. Additionally, a single heat exposure (45 degrees C.) of 30 minutes at 24 hours prior to challenge consistently reduced the severity of anaphylaxis. Single heating exposures at 24 hours prior to sensitization or at 48 hours prior to challenge did not influence the anaphylactic response. In one of two experiments single heat exposures at one hour prior to challenge reduced the severity of anaphylaxis. The levels of anti-BSA antibody which existed immediately prior to challenge were not affected by the heat treatments. These data demonstrate clearly that exogenous ACTH and a single, non-lethal heating episode, when applied 24 hours prior to the induction of anaphylaxis, reduced the severity of the symptoms associated with this particular hypersensitive reaction in the domestic chicken.

Adrenocorticotropic Hormone↗
PubMed1975

Enhanced immunosuppression in bursectomized chickens by passive transfer of antibody.

Three trials were conducted using commercial broiler cockerels to determine the immunological consequences of passive transfers of immune sera to bursectomized chickens. The data illustrate that passive transfers of immune sera to juvenile chickens which had been surgically bursectomized immediately after hatching caused a suppression of the primary hemagglutination response which was greater than that caused by bursectomy or passive transfer of immune sera alone. However, when these same birds were given a secondary challenge of antigen the resulting secondary hemagglutination response was normal. These data indicate that the passive transfer of immune sera to bursectomized chickens greatly limits their ability to mount primary humoral responses, while not affecting the ability to develop anamnestic immunity.

Animals↗
PubMed1975

Estimation of protein content in the plasma of young chickens by a refractometric method.

This study was conducted to evaluate a refractometric method for determination of protein content of chicken plasma. Comparison of the results obtained with the refractometric and the Lowry methods indicated that refractometry, when used with due caution in a typical laboratory situation, provided a simple, fast, inexpensive and valid method for determining the protein content of plasma from young chickens.

Animals↗
PubMed1975

In vitro reactivity of chicken hemagglutinins in the presence of corticosterone.

Exogenous corticosterone at the levels of 0, 2, 4, or 8 mug./100 ml. in excess of physiological levels did not affect the in vitro reactivity of chicken anti-SRBC hemagglutinins. These results suggest that immunosuppression which results via stimulation of the adrenal cortex is not attributable to a direct effect of corticosterone on antibody reactivity.

Agglutinins↗
PubMed1975

Toxicity of dietary lead in Japanese quail.

The toxicity of dietary lead in Japanese quail was investigated. The data indicated that dietary lead, in the form of lead acetate, was toxic to young quail at the level of 500 p.p.m. and this toxicity was evidenced by an inhibition of normal growth and by anemia. The anemic state in the lead toxic quail was more readily detected by reduced blood hemoglobin concentrations than by packed cell volumes. In addition, the data suggested that lead interfered with normal sexual development in the males. Lead at levels as high as 1000 p.p.m. did not prevent normal primary antibody responses to sheep erythrocytes.

Animal Feed↗