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L D Bacon

Publications and source records attributed to L D Bacon.

At least 55 records · Page 3Linked to original sources
PubMed1987

Influence of the major histocompatibility complex on disease resistance and productivity.

Publications in which chickens of different B haplotypes were studied for differences in disease resistance or productivity traits are reviewed. The most prominent effects on diseases are those involving tumors, but other examples involving autoimmune disease and microbial infections not resulting in neoplasia or autoimmunity are also cited. Each referenced disease paper is briefly defined with regard to: population used, B alleles present, and the most resistant B types. Studies citing B haplotype influences on productivity and reproductive fitness traits are summarized and the most desirable B genes in each referenced population are given. Plausible mechanisms of the B haplotype's influence on the traits are briefly discussed. Based on the evidence reviewed for disease resistance and productivity traits and the central role of B-complex genes in immune function, it is concluded that poultry breeders should develop B-genotype information in their base breeding populations and use those types yielding optimal performance.

Animals↗
PubMed1987

Allograft and antibody responses of 15I5-B congenic chickens.

Seven congenic lines of chickens that differ from the parental inbred line RPRL-15I5 for genes in the major histocompatibility (B) complex are under development. After 2 to 5 generations of crossing B-homozygous chickens were produced for interim histocompatibility and antibody competence tests. Chickens in each of the B-congenic lines had antigens determining rapid skin graft rejection and stimulation of mixed lymphocyte responses by 15I5 chickens. Several lines repeatedly developed different antibody responses after immunization with sheep red blood cells, killed Brucella abortus, and Infectious Bursal Disease Virus Vaccine.

Animals↗
PubMed1986

Tests of association of immunoglobulin allotype genes and viral oncogenesis in chickens.

Chickens from Regional Poultry Research Laboratory (RPRL) inbred line 6(3) are resistant to virally-induced Marek's disease (MD) and lymphoid leukosis (LL) and are relatively strong regressors of virally-induced Rous sarcomas. In contrast, RPRL line 100 chickens are highly susceptible to MD and LL and are weaker regressors of Rous sarcomas than line 6(3). RPRL lines 100 and 6(3) differ for alleles at the IgG-1 (G-1) allotype locus, but have identical IgM-1 (M-1) allotype alleles. To test the possible association of the G-1 locus with variations in resistance to virally-induced tumors, homozygous and heterozygous genotypes among F3 crosses were infected. F3 chickens with different G-1 types were comparable in their resistance to MD tumors following inoculation with the JM strain of the MD virus, and for their ability to regress Rous sarcoma tumors induced by the Rous sarcoma virus (RSV) RAV-1. However, following RAV-1 virus infection a smaller proportion of G-1a/G-1aF3 or F4 birds developed LL tumors than G-1a/G-1e and G-1e/G-1e birds. Genes determining immunoglobulin heavy chains were therefore associated with a recessive resistance to B-cell lymphomagenesis in chickens.

Animals↗
PubMed1986

Genetic variation in the recruitment and activation of chicken peritoneal macrophages.

Genetic variation in the ability to recruit and activate peritoneal macrophages was examined in seven partially developed 15I5-B congenic White Leghorn chicken lines. While the ability to generate peritoneal exudate cells (PECs) was similar in all lines, major differences were observed in the numbers, composition, and functional activity of harvestable peritoneal adherent cell populations. In response to a general stimulant, Sephadex, lines .7-2 and .6-2 produced the greatest numbers of adherent peritoneal cells while lines .C-12 and .15I-5 were among the poorest responders. Macrophage percentage of adherent PECs varied between lines. 15I5 chickens produced a consistently high percentage of adherent macrophages while .6-2 birds exhibited the lowest macrophage percentage at all ages examined. Phagocytosis was used as one measure of the level of macrophage activation and similar results were obtained using both opsonized and unopsonized sheep erythrocytes; adherent peritoneal cells from lines .6-2, .7-2, and .P-13 exhibited the highest activity and .C-12, .15I-5, and background 15I5(B15) lines produced cells with the lowest phagocytic activity. In a second functional assay, the killing of Salmonella typhimurium, macrophage-rich cells from line .P-13 exhibited the lowest activity which was significantly lower than that obtained with cells from lines .6-2 and .15I-5. Antigen-specific stimulation of peritoneal adherent cells by ferritin also showed that .C-12 was a low responder in contrast with other lines. The results indicate that these genetic lines differ in peritoneal macrophage function and suggest that the chicken major histocompatibility complex may influence certain properties of chicken macrophage function.

Animals↗
PubMed1986

Cryopreservation of chicken semen of inbred or specialized strains.

Pooled semen from several inbred special chicken strains was diluted with solutions containing glycerol or dimethylacetamide as a cryoprotectant. One-half milliliter samples in capped glass vials were frozen at 3 C/min to -35 C in a programmable freezer and stored in a nitrogen vapor tank. One vial of thawed semen was used to inseminate 4 hens by intravaginal, intrauterine, or intramagnal procedures. The intramagnal technique required minor surgery but always produced chicks in seven lines in contrast to the nonsurgical methods. Frozen semen of one strain stored for 29 weeks produced 12 to 14 chicks per vial when inseminated into 4 hens. This method, therefore, will reliably rescue gene pools from semen after long-term storage.

Animals↗
PubMed1985

Tests of association of lymphocyte alloantigen genotypes with resistance to viral oncogenesis in chickens. 2. Rous sarcoma and lymphoid leukosis in progeny derived from 6(3) X 15(1) and 100 X 6(3) crosses.

Chickens from inbred line RPRL 6(3) are resistant to virally-induced Marek's disease (MD) and lymphoid leukosis (LL) and are relatively strong regressors of virally induced Rous sarcomas. Line 6(3) chickens are homozygous for three independent loci determining surface alloantigens of lymphocytes, Th-1 and Ly-4 on thymus-derived (T) cells and Bu-1 on bursa-derived (B) cells. In contrast, RPRL Lines 100 and 15(1) are highly susceptible to MD and LL and are weaker regressors of Rous sarcomas than 6(3). RPRL Lines 100 and 15(1) are homozygous for different alleles at the Th-1 and Ly-4 loci than 6(3), whereas only Line 100 differs from 6(3) at Bu-1. To test the possible association of these three antigen loci with variations in resistance to virally-induced tumors, homozygous genotypes among later generations derived from 6(3) X 15(1) and 100 X 6(3) crosses were identified by means of immunofluorescence testing of peripheral blood lymphocytes. Test progeny were then bred from matings of homozygous parents. No association was found between Rous sarcoma regression and the Th-1 and Ly-4 T cell alloantigen loci in F6 (6(3) X 15(1)) chickens, but the Bu-1 locus influenced rate of regression in F3 (100 X 6(3)) chickens. The Ly-4 in F6 (6(3) X 15(1)) and Bu-1 in the F3 (100 X 6(3)) chickens did not influence the incidence of LL. However, Th-1 influenced LL in F3 (100 X 6(3)) chickens (P less than .05) and possibly influenced LL in F6 (6(3) X 15(1)) chickens (P less than .09).

Animals↗
PubMed1984

AT-1.1: a thymus-specific alloantigen of chickens.

A thymocyte-specific alloantigen, designated AT (avian thymus)-1.1, has been detected in Cornell C strain (CS) and Obese strain (OS) chickens, the latter being a strain derived from CS which develops a spontaneous form of autoimmune thyroiditis (SAT). Antisera specific for this antigen were developed first in a turkey immunized with thymocytes from an OS chicken and, later, in AT-1.1-negative CS chickens immunized with AT-1.1-positive thymocytes. AT-1.1 was detected in 50-70% of cells in a thymus cell suspension, but was not seen on peripheral blood lymphocytes, erythrocytes, or cells from bursa, spleen, kidney, liver, or brain. It was present on thymocytes of chickens at all ages tested, from 1 day to 6 months of age. AT-1.1 was not detected in six chicken lymphoid tumor cell lines tested, and birds expressing it were found to be negative for the presence of Marek's disease viral antigens. Pedigree studies on 287 (OS X CS)F2 chickens demonstrated that AT-1.1 is expressed in a dominant or codominant manner, and the gene coding for this antigen was not linked to the beta (major histocompatibility) complex. The genetics and tissue distributions of AT-1.1 indicate that it differs from thymus cell surface antigens, avian or mammalian, previously described.

Animals↗
PubMed1984

The ontogeny of blood cells, complement, and immunoglobulins in 3- to 12-week-old 15I5-B congenic white Leghorn chickens.

Six partially developed line 15I5-B congenic White Leghorn chicken strains were used to investigate age and B haplotype effects on hematocrit, total and differential leukocyte counts, hemolytic complement, immunoglobulins, and body weights. The .C-12 line had the lowest hematocrit values throughout the study. The .15I-5 line always had the highest mean hematocrit value and differed from the .C-12 and .P-13 lines at 3, 8, and 12 weeks, as well as lines .N-15 and .6-2 at 12 weeks. Ontogenically, the total leukocyte, hemolytic complement, immunoglobulins, and body weight values increased after 3 weeks in all lines. Lymphocytes were the predominant leukocyte after 3 weeks in all lines studied. At 12 weeks, the .C-12 line had the highest total leukocytes, heterophils, lymphocytes, and monocytes among the lines studied. The .6-2 line had a significantly higher hemolytic complement level than the .P-13 or the .C-12 line at all 3 ages, and at 12 weeks it also differed from the .7-2 line. The lines were found to be comparable for immunoglobulin classes M and G. In this study the line 15I5-B congenic lines differ for the traits of hematocrit and hemolytic complement level, and the results suggest the difference may be determined by genes in the B complex.

Age Factors↗
PubMed1983

Word frequency effect and recognition memory in dementia of the Alzheimer type.

Normal persons show better recognition memory for rare than for common words. In the first experiment, we examined this word frequency effect in 17 patients with dementia of the Alzheimer type (DAT) and 20 normal controls of equivalent age and education. The DAT patients showed a normal tendency to false alarm to common words but failed to show the normal rare word advantage in their hit rate. In a second experiment, we examined normal memory immediately and after a delay of 1 week when it is approximately equivalent to that of DAT patients. There was no attenuation of the usual rare word advantage. These findings suggest that DAT patients fail to encode the featural and intrastructural elements of to-be-remembered verbal information and that this processing deficit may contribute to their impaired recognition memory performance.

Adult↗
PubMed1983

Primary memory and secondary memory in dementia of the Alzheimer type.

Free recall of word lists was investigated in a sample of 47 patients with dementia of the Alzheimer type (DAT) and 31 normal controls of equivalent age and education. Recall was divided into primary memory (PM) and secondary memory (SM) components based on the number of items intervening between presentation and recall. The findings were as follows: (1) the patients showed a greater deficit on the SM than on the PM measure; (2) there was little evidence of proactive interference in the patient group; (3) the PM and SM measures were independent in the controls but not in the patient group; and, (4) the size of patients' PM deficit increased linearly with increasing items between presentation and attempted recall. These results suggest that the memory disorder of DAT is partially the result of defective PM.

Aged↗
PubMed1983

Chronic dopaminergic sensitivity after Sydenham's chorea.

We studied psychometric performance on the Minnesota Multiphasic Personality Inventory (MMPI) mini-mult and drug-induced choreic reactions in a group of patients with a history of Syndenham's chorea. Action tremor, motor signs, and residual chorea were common. One-half of the patients reported adverse choreic reactions to one or more agents. Patients with adverse reactions to central stimulants and anorectics had statistically significant elevations in the psychotic tetrad of the MMPI. Sydenham's chorea in childhood seems to confer persistent sensitivity to agents that augment central dopaminergic activity, which may be expressed as acute chorea. Central dopaminergic sensitivity may explain earlier reports of psychologic difficulties in survivors of rheumatic chorea.

Adult↗
PubMed1983

B5 and B15 associated with progressive Marek's disease, Rous sarcoma, and avian leukosis virus-induced tumors in inbred 15I4 chickens.

RPRL 15I4 inbred chickens are nearly histocompatible except for the B5 and B15 haplotypes that determine the major transplantation antigens. B5B5 and B15B15 15I4 chickens were equally and highly susceptible to tumors induced by Marek's disease, Rous sarcoma, or avian leukosis viruses (ALV), suggesting both of these haplotypes may determine a general influence leading to tumor development. The 15I4 birds were highly susceptible to erythroblastosis, and most developed immunological tolerance to the virus after ALV infection.

Animals↗
PubMed1983

Ontogeny and line differences in the mitogenic response of chicken lymphocytes.

Ontogeny of mitogen response was studied using Regional Poultry Research Laboratory lines 6 and 7 and Cornell lines JM-N and -P chickens over a 30-week experimental period. Purified lymphocyte assay and sequential monitoring with whole-blood assay show lines 6 and N to be low responders compared to lines 7 and P, respectively. The difference in phytohemagglutinin (PHA) response between lines 6 and 7 increased with age, whereas that between lines N and P remained consistent for all ages. An association seems to exist between the low PHA responsiveness of lines 6 and N and resistance to Marek's disease (MD), a lymphoproliferative disease caused by MD virus in susceptible chickens. The fact that lines 6 and 7 have the same B2-haplotype but differ in PHA response seems to substantiate the evidence by others that the genetic control of PHA response is not linked to the Ea-B locus of the MHC complex. This does not preclude, however, the possibility that the response of lines N and P is MHC-linked.

Aging↗
PubMed1983

A monoclonal antibody reactive with Marek's disease tumor-associated surface antigen.

An antibody-secreting hybridoma, RPH-6, to Marek's disease tumor-associated surface antigen (MATSA) was produced by somatic-cell hybridization between the mouse myeloma SP2/O-Ag/14 and spleen cells from MSB1 immunized mice. The antibody reacted with 95 to 100% of the cells from eight of 10 chicken MD cell lines and one of two turkey MD cell lines. It did not react with chicken MD cell lines RP1 and SK3, turkey MD cell line RP19, lymphoid leukosis (LL) cell lines, RP9 and RP12, and reticuloendotheliosis virus (REV) cell line RP14. A weak reaction was observed with REV cell line RP13 (10 to 20%), and a very slight reaction with normal chicken spleen cells (1 to 5%). RPH-6 produces immunoglobulin of the IgM class. Cell culture and mouse ascitic fluids have titers of 10(2) and 10(6), respectively, by fluorescent antibody (FA) test against MD tumor cell lines. The antibody did not react with Marek's disease virus (MDV) internal antigen or membrane antigen as detected by indirect FA test on chicken embryo fibroblast cultures grown on coverslips. The 51Cr release assay showed RPH-6 is highly cytotoxic (60% release) only against MD lymphoblastoid cell lines, with antibody prepared from mouse ascites having a cytotoxic titer approaching 10(6). Results from using RPH-6 for differential diagnosis of chicken lymphoid tumors of unknown origin were in complete agreement with those obtained with rabbit anti-MATSA reference serum and pathologic diagnosis.

Animals↗
PubMed1982

Facial recognition memory in dementia.

Previous investigations of memory in senile dementia of the Alzheimer's type (SDAT) have focused on verbal learning and memory. The aim of the present study was to determine whether the amnesia of SDAT is limited to verbal material. Patients with SDAT (N = 29; mean age = 69.3) and healthy normal controls (N = 41; mean age = 69.3) were given a test of facial perception and two recognition memory tasks, one for words and one for faces. The results indicate that dementia patients show a deficit in the retention of facial information. This deficit cannot be attributed to faculty initial perception or to a response bias. The verbal and facial memory deficits in SDAT appear to differ: performance on tests of verbal and facial memory is relatively independent, and substantial encoding and linguistic defects contribute to the verbal, but not the facial, memory disorder resulting in more severe impairment on tests of verbal memory. The implications of these findings for research on the neuropharmacology and pathophysiology of SDAT are discussed.

Aged↗
PubMed1982

Immunocompetence of chickens during early and tumorigenic stages of Rous-associated virus-1 infection.

A study was designed to determine the effects of congenital infection with the Rous-associated virus-1 (RAV-1) on the immune function chickens during the early and late tumorigenic stages of infection. In another experiment, the effects of niridazole on the immune competence and the tumor incidence in chickens congenitally infected with RAV-1 were studied. Lymphocyte stimulation by phytohemagglutinin, the phytohemagglutinin skin test, the response to immunization with sheep erythrocytes and Brucella abortus, and histological evaluation of lymphoid organs were used to determine the immune competence in normal and infected chickens. Results indicated that both B- and T-cell immune functions during the early and late stages of RAV-1 infection were comparable to those of normal uninfected chickens. Administration of niridazole to congenitally infected chickens at 5 weeks of age for 7 or 21 days had no effect on the T-cell-mediated immunity; however, administration of the drug for 21 days eliminated lymphoma development. Unlike infection with other oncogenic viruses such as those causing Marek's disease and reticuloendotheliosis, infection with RAV-1 caused no detectable immunodepression during the early and late stages of infection.

Animals↗