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Biomedical subjects

R L Taylor

Publications and source records attributed to R L Taylor.

At least 55 records · Page 3Linked to original sources

Continuous administration of dopamine alters cellular immunity in chickens.

Dopamine administered continuously through osmotic pumps altered the PHA wattle response and in vitro leukocyte capillary tube migration in UNH 105 chickens. The PHA wattle response was suppressed significantly by 48 hr exposure to dopamine at a dose of 1 microgram/hr. Administration of 10 micrograms/hr dopamine for 48 hr enhanced significantly in vitro leukocyte migration.

Animals↗

Analysis of macrophage functions in Rous sarcoma-induced tumor regressor and progressor 6.B congenic chickens.

Macrophage functional competence was studied in two congenic chicken lines 6.6-2 (B2B2) and 6.15-5 (B5B5) which are regressors and progressors, respectively, of Rous sarcoma-induced tumors. Sephadex-elicited abdominal exudate cells (AEC) were harvested from 4-week-old chickens to determine their total number, glass adherence potential, percentage of adherent macrophages and phagocytosis of antibody coated (ops) and uncoated (unops) sheep red blood cells (SRBC). Tumoricidal abilities of culture medium conditioned with lipopolysaccharide treated macrophages and of macrophages cocultured with target cells were assessed against 51Cr-labelled tumor cell targets. The congenic lines did not differ in total AEC or percent macrophages. However, AEC from B5B5 birds exhibited significantly lower (P < 0.05) glass-adherence potential than AEC from B2B2 birds exhibited significantly lower (P < 0.05) glass-adherence potential than AEC from B2B2 birds. The percentage of phagocytic macrophages did not differ between lines for unop-SRBC, whereas a higher percentage of B5B5 compared with B2B2 birds (P < 0.05) macrophages phagocytized ops-SRBC. Macrophages from B5B5 birds had significantly (P < 0.05) lower activity in both tumoricidal tests. These results imply that the tumor progression in B5B5 birds is associated with reduced activation of macrophages towards a tumoricidal pathway.

Animals↗

Comparative development of Eimeria tenella in primary chick kidney cell cultures derived from coccidia-resistant and -susceptible chickens.

A sixfold difference in resistance to coccidia (Eimeria tenella) infection between a resistant and a susceptible line of Auburn White Leghorn chickens, derived by selective breeding, has been reported. The purpose of the following study was to determine whether the resistance or susceptibility phenomenon in the Auburn lines could be manifested in a homogeneous group of isolated host kidney cells that support E. tenella development in vitro but not normally in vivo. Propagation of the parasite in host cells in vitro eliminates humoral and cellular elements of immunity, and allows the study of host genetic influences at the cellular level. Differences in parasite development were examined between the two lines of cells in vitro after 48 and 96 h of incubation; time periods that reflect initial infection of the host cells by the parasite and the subsequent asexual development. Quantification of differences by liquid scintillation counting was based on parasite-specific incorporation of pyrimidines, specifically [3H]-uracil. The results supported previous findings that overall E. tenella development was significantly greater in the host cells from the susceptible line than in the cells from the resistant cultures at both time periods.

Animals↗

Biogenic amines regulate avian immunity.

Alzet mini-osmotic pumps were implanted subcutaneously to administer norepinephrine (NE) and epinephrine (E) to 6-wk-old line UNH 105 chickens. Dose-time studies showed the most effective NE and E dose and exposure time on two chicken cellular immune responses: the phytohemagglutinin (PHA) wattle response and leukocyte migration. Administration of 1 microgram/h NE for 72 h suppressed significantly the wattle stimulation index [2.48 +/- .3 (SE)] compared to that of saline controls (4.1 +/- .3) but enhanced mean leukocyte migration (7.7 +/- .3 versus 4.9 +/- .3). Epinephrine at 1 microgram/h for 72 h significantly suppressed the wattle index (1.8 +/- .2) compared to that of controls (2.8 +/- .3) but E at 1 microgram/h for 48 h enhanced leukocyte migration (9.5 +/- .2 versus 6.4 +/- .2). Continuous administration of NE and E at physiological levels alters cell-mediated immunity and appears to have an immune regulatory role in the chicken.

Animals↗

The effects of prolonged weightlessness and reduced gravity environments on human survival.

The manned exploration of the solar system and the surfaces of some of the smaller planets and larger satellites requires that we are able to keep the adverse human physiological response to long term exposure to near zero and greatly reduced gravity environments within acceptable limits consistent with metabolic function. This paper examines the physiological changes associated with microgravity conditions with particular reference to the weightless demineralizatoin of bone (WDB). It is suggested that many of these changes are the result of physical/mechanical processes and are not primarily a medical problem. There are thus two immediately obvious and workable, if relatively costly, solutions to the problem of weightlessness. The provision of a near 1 g field during prolonged space flights, and/or the development of rapid transit spacecraft capable of significant acceleration and short flight times. Although these developments could remove or greatly ameliorate the effects of weightlessness during long-distance space flights there remains a problem relating to the long term colonization of the surfaces of Mars, the Moon, and other small solar system bodies. It is not yet known whether or not there is a critical threshold value of 'g' below which viable human physiological function cannot be sustained. If such a threshold exists permanent colonization may only be possible if the threshold value of 'g' is less than that at the surface of the planet on which we wish to settle.

Adaptation, Physiological↗

Major histocompatibility (B) complex control of the growth pattern of v-src DNA-induced primary tumors.

Observations that the major histocompatibility (B) complex is a determinant of the growth pattern of Rous sarcoma virus (RSV)-induced tumors raised the question as to whether control is exerted at the level of a v-src-determined, i.e., transformation-specific, function. To investigate this point, the tumor size scores and tumor profile indices of v-src-induced tumors were compared in two lines of chickens congenic for B complex genotypes. The finding that the growth patterns of tumors, induced by v-src DNA inoculation at 6 weeks posthatch, differ in these two lines establishes that the B complex exerts control over tumor growth at the level of a v-src-determined function. The potential importance of this control, in terms of the naturally occurring case of an avian sarcoma virus infection, is suggested by the observation that the patterns of tumor growth in a given congenic line are similar whether the tumors are induced by v-src DNA or by RSV.

Animals↗

Dietary arginine influences Rous sarcoma growth in a major histocompatibility B complex progressor genotype.

L-Arginine (L-Arg) can serve as a substrate for the production of reactive nitrogen intermediates. One of these metabolites, nitric oxide, has been shown to possess significant antitumor properties in vitro. To investigate the importance of this system in vivo, we have examined the dietary L-Arg host tumor interaction in the chicken. Since chickens are incapable of de novo L-Arg synthesis, concentration of this amino acid is readily controlled by diet. Line UNH 105 New Hampshire chickens having the major histocompatibility complex genotype, B24/B24, were used to study in vivo effects of dietary L-Arg on Rous sarcoma growth. After 5 weeks on a standard diet, 119 chicks were fed either a basal (0.92% L-Arg) diet or a high arginine (2.40% L-Arg) diet. One week later, chicks were wing-web inoculated with subgroup A Rous sarcoma virus. Tumor growth was monitored weekly for 12 weeks after inoculation. Plasma L-Arg levels and body weights from birds on each dietary treatment were analyzed. Neither body weight gains nor latent period for tumor development was affected by diet. However, plasma L-Arg levels were significantly different between dietary treatments (basal, 0.245 +/- 0.01 mumol/ml; high, 0.738 +/- 0.03 mumol/ml). In addition, mean tumor size scores were significantly (P less than 0.05) lower over time in chickens fed the high L-Arg diet. The results suggest that dietary L-Arg in excess of the amount required for growth reduces tumor load.

Animals↗

Differential resistance to Staphylococcus aureus challenge in major histocompatibility (B) complex congenic lines.

Ten inbred B-congenic Leghorn lines were challenged with two isolates of Staphylococcus aureus at 3 days and 6 wk of age. Significant differences in mortality were observed among such lines when challenged at 3 days with either S. aureus Isolate P4L (moderately pathogenic) or S. aureus Isolate 3727 (highly pathogenic). Line 331 (B2/B2 genotype) had lower mortality than either Line 004 (B17/B17, chi 2 = 4.13, P < .05) or Line 253 (B18/B18, chi 2 = 4.23, P < .05) challenged with Isolate P4L. The use of a susceptibility index allowed for the detection of additional differences among the various lines challenged by Isolate 3727. Line 336 (BQ/BQ) was more resistant than either Line 335 (B19/B19, P < .01) or Line 330 (B21/B21, P < .01). No significant differences were found among the lines challenged at 6 wk by either isolate. The results provide additional evidence for the importance of the B complex in genetically determined disease resistance, and further demonstrate the usefulness of congenic lines in such investigations.

Animals↗

Multisite immunochemiluminometric assay for simultaneously measuring whole-molecule and amino-terminal fragments of human parathyrin.

The immunochemiluminometric assay described uses immobilized anti-human parathyrin (parathyroid hormone, hPTH)(1-44) and anti-hPTH(44-68) antisera and acridinium ester-labeled anti-hPTH(1-34) to simultaneously measure both intact hPTH and its amino-terminal fragments. Results by the assay correlate well with those by a cAMP-based bioassay and the Nichols Allegro immunoradiometric assay. The minimal detection limit is 0.08 pmol/L. The normal range is 1.0-5.0 pmol/L, and values are higher in older women. About 90% of study patients with surgically proven parathyroid adenomas had above-normal preoperative PTH concentrations, whereas patients with hypercalcemia of malignancy had normal or suppressed values. This assay was designed to detect both intact PTH and amino-terminal PTH fragments; however, chromatographic fractionation of pools of primary and secondary hyperparathyroid plasma showed virtually no amino-terminal fragment activity. Nonetheless, the design is important because the absence of carboxyl-terminal binding sites prevents interference by carboxyl-terminal fragments and because bioactive amino-terminal fragments will react in the assay if they are present in the patients' sera or if they are produced by in vitro proteolysis of intact PTH.

Chromatography↗

Determination of plasma calcitonin gene-related peptide concentrations by a new immunochemiluminometric assay in normal persons and patients with medullary thyroid carcinoma and other neuroendocrine tumors.

There is doubt about concentrations of circulating calcitonin gene-related peptide (CGRP) and the value of plasma CGRP measurements in the detection and follow-up of medullary thyroid carcinoma (MTC). Thus, we developed an immunochemiluminometric sandwich assay for CGRP using antibodies purified from a polyclonal antiserum against human CGRP. The assay was sensitive (limit of detection, 0.4 pmol/L; multiply by 3.7892 to derive nanograms per L) and highly specific [no cross-reaction with human calcitonin (CT)]. Normal plasma CGRP values ranged from less than 0.4 to 4.5 pmol/L (median, 0.8; n = 31), with 61% having detectable levels. Values in samples from patients with MTC were elevated: unoperated patients (n = 10), 4.7-137 pmol/L (median, 7.1); and operated patients with gross persistent or recurrent tumor (n = 14), 4.7-171 pmol/L (median, 23.2). In contrast, CGRP values were normal in 78% of nine postoperative patients with elevated CT, but no detectable tumor (range, less than 0.4 to 6.3 pmol/L; median, 1.6). CGRP levels increased after pentagastrin injection in MTC patients, but less than did CT values. Cultured MTC cells in vitro secreted large amounts of CGRP, and rat nerve root ganglia, human osteoblasts, and microvessel endothelial cells secreted lesser amounts. We conclude that CGRP circulates in normal plasma, but at very low levels. Plasma CGRP concentrations are frequently high in patients with MTC, but primarily in those with gross tumor or metastases. Plasma CT assay is the preferable test for MTC, but CGRP assay deserves prospective study for a possible role in predicting gross metastasis.

Animals↗

Effects of guidance intervention on perceived school behavior and personal self-concept: a preliminary study.

In this preliminary study, 10 of 20 gifted fifth-grade students experiencing stress were randomly assigned to either a control group or structured guidance intervention. Significant differences on measures of self-concept were noted between the treated and the control group. The treated group also significantly improved on self-reported measures of self-concept and perceived school behavior. Teachers reported less acting out and improved compliance.

Child↗

Differential resistance to Staphylococcus aureus challenge in two related lines of chickens.

Trials were conducted to determine whether differential resistance to challenge with Staphylococcus aureus was characteristic of two related lines of New Hampshire chickens differing genetically in size of the bursa of Fabricius. Neonatal small bursa line (SBL) chicks were superior to the unselected Lester J. Dreesen (LJD) line in five of six trials employing intracardiac challenge (chi 2 = 6.3, .05 greater than P greater than .01). Older (7 to 12 wk) SBL chicks, challenged intravenously, had superior resistance than Line LJD chicks in three of four trials where a direct comparison was possible. The mortality rate in Line SBL was 34% in all trials compared with a 54% mortality rate (chi 2 = 11.7, P less than .001) in Line LJD. Moreover, the development of morbidity was more rapid in Line LJD. It is suggested that these lines can be of use in investigations of the nature of resistance to staphylococcal disease.

Animals↗

Signal transduction events in chicken interleukin-1 production.

The HD11 chicken macrophage cell line was studied for growth characteristics using different culture media, serum concentrations, and incubation temperatures. Growth curves at 37 C revealed that the cells grew best in RPMI 1640 medium supplemented with 10% colostrum-free bovine serum (CFBS). Growth was not supported by RPMI 1640 medium supplemented with the serum replacement Nu Serum nor by PC-1 culture medium alone. However, coating culture plates with either chicken serum or Nu Serum enhanced HD11 cell growth in the PC-1 medium. Growth at 40 C was equivalent to that obtained at 37 C when RPMI 1640 medium with 10% CFBS or PC-1 medium in plates coated with chicken serum were used. Several stimuli were tested for their ability to induce interleukin-1 (IL-1) in HD11 macrophages under serum-free conditions. Lipopolysaccharide (2.5 micrograms/mL) or silica (50 micrograms/mL), increased extracellular IL-1 significantly after a 24-h treatment. In contrast, a superinduction protocol using phorbol 12-myristate 13-acetate, cycloheximide, butyrate, and actinomycin D did not increase extracellular IL-1 significantly. All three stimulants significantly elevated intracellular IL-1 after treatment. Protein kinase C inhibitors (H7 and retinal) as well as calmodulin-dependent kinase inhibitors (W7 and TFP) significantly diminished IL-1 production in the intracellular and extracellular compartments. Elevated cyclic adenosine 5'-monophosphate (cAMP) actuated by dibutyryl cAMP also increased IL-1 significantly. The dat indicate that both protein kinase C and calmodulin-dependent kinase mechanisms are important in signal transduction leading to IL-1 production.

Animals↗

Modulation of chicken plaque-forming cells by serotonin and dopamine.

Serotonin (5-hydroxytryptamine, 5-HT) and dopamine (DA) are endogenous components of the central nervous and endocrine systems of the chicken. To determine the effects of these monoamines on antibody-mediated immunity. New Hampshire chickens of Line UNH 105 were injected intravenously with 5-HT (100 micrograms/kg of body weight) and DA (1 mg/kg of body weight). One milliliter of a 5% SRBC suspension was injected intravenously 30 min later. Both IgM and IgG splenic plaque-forming cells were assayed 5 days after antigen injection. For in vitro studies, spleen lymphocytes from SRBC-primed chicks were incubated with DA and 5-HT followed by quantitation of IgM and IgG plaque-forming cells. The in vivo incubation of splenic lymphocytes with specific antagonists was used to ascertain the presence of monoamine receptors on lymphocytes. The 5-HT significantly enhanced IgM plaque-forming cells compared with controls following in vivo [550 +/- 85 (SE) cells/10(6) splenic lymphocytes versus 359 +/- 44] but not in vitro exposure. The IgG plaque-forming cells were not affected by 5-HT. The DA significantly suppressed IgM plaque-forming cells responses following in vivo (284 +/- 46 versus 499 +/- 66) and in vitro (254 +/- 57 versus 451 +/- 51) exposure. Significant suppression of IgG plaque-forming cells was found in vivo (287 +/- 40 versus 462 +/- 75) and in vitro (153 +/- 36 versus 371 +/- 81) following treatment. Specific DA antagonists, apomorphine and metoclopramide, did not alleviate the in vitro suppressive effect of DA.

Animals↗

Trends in classification usage in the mental retardation literature.

Trends in classification usage were analyzed through examination of all issues of Mental Retardation, American Journal of Mental Deficiency, and American Journal on Mental Retardation from 1980 through 1989. The research was undertaken to determine whether the recommendations by Taylor (1980) and MacMillan, Meyers, and Morrison (1980) regarding subject description had been implemented. Results indicated that the system of the American Association on Mental Retardation (previously the American Association on Mental Deficiency) was used in over 50% of the articles, whereas the American Educators system was used in only 10%. A further analysis regarding the use of various classification systems as a function of the age of the subjects was also conducted. Implications of these results were discussed.

Adolescent↗

Monoamines alter in vitro migration of chicken leukocytes.

The effect of the biogenic amines serotonin (5-HT), dopamine (DA), and norepinephrine (NE) on peripheral blood leukocyte (PBL) migration was studied in two populations derived from line UNH 105 New Hampshire chickens. Maximum migration from capillary tube migration chambers was achieved in 1 hr. An age effect in both populations was indicated by significantly larger migration areas found in leukocytes from 7-week-old chickens compared to those of 4-week-old chicks. Thirty min after intravenous monoamine injection, line UNH 105 PBL migration was unaffected by exogenous monoamines. In the second population, B24/B24 chicks, NE enhanced migration at 4 weeks of age but DA suppressed migration at 7 weeks of age. In vitro exposure of PBL to the biogenic amines also affected leukocyte migration. Migration was augmented by 100 ng 5-HT but suppressed by 1 microgram 5-HT in UNH 105 chicks. Furthermore, DA suppressed PBL migration and NE enhanced migration in the same population. PBL from B24/B24 chicks were not affected by in vitro exposure to 5-HT, however, DA enhanced migration whereas NE suppressed migration. Specific antagonists for 5-HT, DA, and NE blocked the effects of each monoamine suggesting that receptors are present on chicken leukocytes. These receptors mediate action of the monoamines on leukocyte migration activity.

Animals↗