Biomedical subjects
J W Latimer
Publications and source records attributed to J W Latimer.
Plasma cholesterol responses to the adrenocorticotropic hormone in Japanese quail following eighteen generations of divergent selection.
Japanese quail (Coturnix coturnix japonica) lines were divergently selected for plasma cholesterol response to adrenocorticotropin (ACTH). Data for Generations 9 to 18 indicated a greater response in the low (L) line than in the high (H) line, which was contrary to selection responses for the first eight generations. During Generations 9 to 18, selection differentials were greater in the H line; however, heritability estimates were greater in the L line. These data suggest caution in the interpretation of early selection responses for plasma cholesterol. Selection for plasma cholesterol response following ACTH injection also resulted in divergence in plasma cholesterol levels in the H and L lines in the absence of ACTH. Body weights at 31 days were greater in the H line than in the L line, suggesting a possible relationship with the plasma cholesterol level.
Splenic leukocytes from chickens injected with Salmonella pullorum antigen stimulate production of corticosteroids by isolated adrenal cells.
Corticosteroid levels in the blood serum of White Rock pullets were significantly increased within 1 hr after an iv injection of heat-killed Salmonella pullorum antigen (SP-Ag), and reached levels 7 to 10 times that of PBS-injected controls within 2 hr after SP-Ag injection. Incubations with isolated adrenal cells indicated that serum from SP-Ag-injected birds had the ability to stimulate the synthesis or release of corticosteroids twice that of serum PBS-injected birds. Stripping the serum from SP-Ag-injected birds with activated charcoal and precipitated silica (Quso G-32) removed the corticosteroids and the adrenal-stimulating ability. A 2-hr incubation of isolated adrenal cells with leukocytes from spleens removed from chickens 1 hr after injection with SP-Ag, using stripped serum as the medium, stimulated a two- to fivefold increase in corticosteroid as compared to splenic leukocytes from PBS-injected chickens incubated in the same medium. The results indicate that an "ACTH-like" substance was produced by the S. pullorum antigen-stimulated splenic leukocytes.
Agglutinin responses to Salmonella pullorum in Japanese quail selected for plasma cholesterol response to adrenocorticotropin and a model describing the dynamics of the response.
Japanese quail from the S16 generation of lines selected for high (HR) and low (LR) plasma cholesterol response to adrenocorticotropin (ACTH), and the randombred control line (C) from which the selected lines had been derived, were immunized with a heat-killed Salmonella pullorum antigen. Plasma from blood samples taken at 0,5,8, and 12 days postimmunization was titered for total agglutinin levels. A quadratic equation and its first derivative, calculated for each bird, produced mean values by line for maximum titers, mean day of maximum titer, and rate of titer decline. Results indicated that the LR line had significantly lower titers than the HR or C lines but that the HR line reached maximum titer later than the LR line. The rate of titer decline was fastest in the C line.
DDT and metabolite accumulation in adrenal, liver, and brain of broiler chickens.
Four-week old broiler chickens were fed rations with varying levels of technical grade DDT for a 4-week period. DDT and metabolite concentrations were measured in adrenal, liver, and brain. Accumulations per gram of tissue were greatest in the adrenals, followed by those in the liver, then in the brain. All birds fed 2700 p.p.m. of DDT died with 12 days after beginning feeding, and moderate signs of toxicity, such as ataxia and trembling, appeared in those fed 900 p.p.m. Although both DDT metabolites, p,p'-DDE and p,p'-DDD, were found in the tissues, the higher levels of the former indicated that the aerobic conversion of DDE occurs more readily than the anaerobic conversion. Significant quantities of o,p'-DDT appear only in tissues of birds fed high levels of the technical grade DDT.
Accumulation and depletion of dieldrin in visceral fatty tissue of broilers.
White rock chicks were fed a commercial crumbles ration with approximately 1.0 p.p.m. of the active ingreient of technical grade dieldrin added to it. The treated feed was replaced by uncontaminated feed at various times from two to eight weeks of age. Equations were computed to describe the accumulation and depletion of the insecticide in visceral adipose tissue. Accumulations in females were described by polynomial equations with significant quadratic coefficients which indicated that the rate of accumulation leveled off between six and eight weeks. Accumulation rates in males were essentially linear through ten weeks. After removal of dieldrin from the feed, insecticide depletion from fat could be described in both sexes by equations for power curves. Replacement of contaminated feed with uncontaminated feed by two or three weeks of age resulted in concentrations at control or background levels by eight weeks of age. Replacement of contaminated feed with non-contaminated feed at ages later than three weeks did not bring concentrations below those acceptable as non-hazardous for human consumption.
Social interactions and antibody titres in young male chickens (Gallus domesticus).
The influence of social interactions on established antibody titres to a Salmonella pullorum antigen was determined in several Athens Randombred families. In two experiments, a large-bodied, aggresive family and a small-bodied, relatively non-aggressive family were placed in three social environments: (1) Four-bird control groups with no changes in membership once formed; (2) three-bird resident groups to which a new fourth bird was introduced daily; (3) the single bird that had been moved to a new group each day. The normal rate of decline in antibody titres was significantly accelerated in birds that were introduced as new members daily (group 3), but only in members of the small non-aggressive family. In a third experiment, using families relatively close in size and aggressiveness, the effects of social grouping on antibody titres were not significant.
Immune response in broilers fed technical grade DDT.
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The role of the Medical Society in disaster.
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The accuracies of four stereotactic frame systems: an independent assessment.
An independent examination of the accuracy and precision of each of four stereotactic frame systems is provided. The effects of scan slice thickness and angle on system performance are also examined. The frame systems' performances for entry points as well as target points are measured.
Stimulatory effect of avian influenza virus on chicken lymphocytes.
A study was conducted to examine the effect of avian influenza virus (AIV) on chicken lymphocyte activation. Unprimed or Brucella abortus antigen (Ag)-primed lymphocytes were incubated with various doses of the T-cell mitogen concanavalin A (Con A) or Ag, respectively, plus serial dilutions of inactivated AIV for 72 hr, and cell proliferation was measured via uptake of tritiated thymidine. AIV enhanced the proliferative response to Con A or Ag by 150% or better, and the enhancement decreased in a viral dose-dependent manner. The effects were more readily observed in cells that had not been maximally activated by the Con A or Ag. The enhanced response was observed in lymphocytes from both white rock and white leghorn breeds of chicken and in mature peripheral blood lymphocytes or immature thymocytes. The viral activity could be abrogated by pre-treatment of the viral preparation with AIV-specific antisera or prior adsorption of the AIV with chicken erythrocytes. These results indicate that AIV can interact with and modify the in vitro activity of chicken lymphocytes and may exert modulatory effects on the avian immune system.