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Biomedical subjects

J W Latimer

Publications and source records attributed to J W Latimer.

At least 19 recordsLinked to original sources
PubMed1995

A novel carbohydrate addition site on the hemagglutinin protein of a highly pathogenic H7 subtype avian influenza virus.

The highly pathogenic (HP) avian influenza isolate, A/Fowl/Victoria/76 (H7N7), contains two naturally occurring hemagglutinin (HA) variants. The two hemagglutinin proteins differ only in the possession of a potential asparagine-linked glycosylation site at amino acid position 188-190, which is near the proposed receptor binding region of the HA. Expanded virus plaques which possess the addition site exhibit more slowly migrating HA1 subunits and are significantly more lethal in chickens than those which lack the site. When artificial mixtures of the two variants were inoculated in birds, as few as 1 in 1000 particles containing the glycosylation site was sufficient to exhibit 100% lethality in birds. The data raise the possibility that presence of carbohydrate near the receptor site on the H7 avian influenza virus hemagglutinin may influence virulence.

Amino Acid Sequence↗
PubMed1992

Fee crisis.

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Fees, Dental↗
PubMed1990

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.

Adrenocorticotropic Hormone↗
PubMed1988

Consumerism.

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Community Participation↗
PubMed1985

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.

Adrenal Cortex↗
PubMed1984

Plasma constituents and body weights of Japanese quail (Coturnix coturnix japonica) selected for twelve generations for plasma cholesterol responses to adrenocorticotropin.

Japanese quail were selected bidirectionally over 12 generations for plasma cholesterol (PC) responses to adrenocorticotropin (ACTH). In addition to the selected trait, plasma corticosteroids (PCS), triglycerides (PT), and glucose (PG) were measured before and after 3 daily injections of ACTH. The quail were also weighed at 31 days of age. By the 12th generation of selection, when measurements were expressed as deviations from the randombred control (C) line from which the selected lines had been derived, there was a difference in PC of approximately 55% between the high response (HR) and the low-response (LR) lines. Pre-ACTH PCS levels increased in all three lines over generations; however, relative to the C line, there was no difference between selected lines. The 3 days of ACTH injection depressed PCS levels. Relative to the C line, pre- and post-ACTH levels of PT were higher in the HR line than in the LR line, and the LR line declined linearly over generations. Levels of PG did not change over generation in the selected lines; however, pre-ACTH levels of PG tended to be higher in the LR line than in the HR line in all generations. Body weights of the HR line at 31 days remained almost exactly the same as the C line, but those of the LR line declined linearly over the 12 generations of selection. These studies demonstrated that the PC response to ACTH was moderately heritable (h2 approximately equal to .20).

Adrenal Cortex Hormones↗
PubMed1984

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.

Adrenocorticotropic Hormone↗
PubMed1984

Interaction of high temperature and Salmonella pullorum antigen concentration on serum agglutinin and corticosteroid responses in white rock chickens.

In three experiments, 6- to 7-week-old chickens were exposed to one or two standard heating episodes and were injected immediately afterward with different concentrations of heat-killed Salmonella pullorum antigen (Ag) or phosphate-buffered saline. The standard heat episode consisted of three .5-hr exposures of 44 to 46 C with .5-hr periods of 22 C between exposures. Nonheated chickens were maintained at 22 C. When two heating episodes were used, there was a 12-hr interval between episodes. Sera from blood collected at 0 through 15 days postimmunization (PI) were titrated for total agglutinins and assayed for corticosteroids in all three experiments. Additionally, in Experiment 3, sera were titrated for 2-mercaptoethanol-resistant (2-MER) antibody. Total agglutinins were suppressed from 5 through 13 days PI by one heating episode in birds receiving lower doses of Ag but not in those receiving higher doses. When birds were exposed to two heat episodes, 12 hr apart, total agglutinin titers were suppressed in birds receiving the low Ag dose during the induction phase (4 to 5 days PI) only. During the declining phase (7 to 14 days PI), the effect was reversed, and titers were significantly lower in heated birds receiving the higher dosage. These results are similar to those previously obtained with ACTH (adrenocorticotropin). Determination of 2-MER antibody indicated that IgM was probably suppressed during the induction of the immune response but that IgG was suppressed during the declining phase of the response. Serum corticosteroid concentrations were significantly increased immediately after exposure to high temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗
PubMed1983

Concentration of Salmonella pullorum antigen and the immunosuppressive effect of adrenocorticotropin in growing chickens.

The role of antigen concentration on the immunosuppressive effect of adrenocorticotropin (ACTH) was tested in 6-week-old White Rock chickens that were immunized i.v. with 1 ml of heat-treated Salmonella pullorum at packed cell volume concentrations of .06 to .00015%, At 16 and 10 hr before the antigen (Ag) injection, the birds received either 4 IU . 100 g body wt-1 of ACTH i.m., or the gelatin (Gel) vehicle. Total, 2-mercaptoethanol sensitive (2-MES), and 2-mercaptoethanol resistant (2-MER) agglutinin antibody titers were determined. The ACTH significantly suppressed total agglutinin titers with the lower Ag concentrations (.0015 and .00015%) but not with the higher Ag concentrations. The ACTH significantly suppressed 2-MES titers only when Ag concentrations were low but suppressed 2-MER titers regardless of Ag concentration. The results indicated that there may be critical Ag concentrations capable of inducing maximal humoral antibody responses in moderate environments but which allow these responses to be suppressed by environments that stimulate increased pituitary-adrenal activity.

Adrenocorticotropic Hormone↗
PubMed1981

Effect of sex hormones on the retention of dieldrin in the fat of growing chickens.

The effects of the bird's sex, castration, and sex hormone replacement on the retention of dieldrin in the carcass fat of growing chickens given low levels of dieldrin in the feed (1 mg/kg) were investigated. Confirmed were previous results that "best-fit" curves for depletion after noncontaminated feed was provided were represented by an equation of the form, y = aX-b, and that, with the approach of sexual maturity, males tend to retain greater concentrations of dieldrin in the carcass fat than females. This sex difference was partly a diluting effect of higher carcass fat deposition in females as compared to males. Additionally, when dieldrin feeding was discontinued after 10 weeks of age, androgen replacement in castrates restricted the clearance of dieldrin from the fatty tissue, and estrogen replacement did not further increase clearance over that of nontreated castrates.

Adipose Tissue↗
PubMed1977

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.

Administration, Oral↗
PubMed1976

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.

Adipose Tissue↗
PubMed1975

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.

Agglutination Tests↗