Search PubMed⌕ Search

Biomedical subjects

C R Wagner

Publications and source records attributed to C R Wagner.

52 records · Page 3Linked to original sources
PubMed1987

Recombinant murine and human IL 1 alpha bind to human endothelial cells with an equal affinity, but have an unequal ability to induce endothelial cell adherence of lymphocytes.

Consistent with the reports of others, we have demonstrated that human peripheral blood lymphocytes adhere to cultured human umbilical vein-derived endothelial cells (EC) in vitro. In our studies adherence was increased twofold to threefold by a 6-hr preincubation of the EC with IL 1. Recombinant human IL 1 alpha induced a maximal adherence response at less than 1 U per 2 X 10(4) EC. In contrast, recombinant murine IL 1 alpha was found to be 250- to 1250-fold less active in the adherence assay, based on units of IL 1 activity defined by the murine thymocyte proliferation assay. Moreover, when EC were preincubated with excess murine IL 1, no inhibition of the adherence-inducing effect of human IL 1 was noted. To characterize further this dichotomy of biological potency of murine and human IL 1 on the adherence assay, IL 1 binding studies were initiated. Recombinant human and murine IL 1 alpha were equally effective in inhibiting the binding of 125I-labeled human and murine IL 1, based on both micrograms of protein and units of IL 1 activity. The results of this study demonstrate that although human and murine IL 1 bind with equal affinity to receptors on human EC, human IL 1 is significantly more potent at inducing the increased EC adhesiveness for lymphocytes. The implications of these results for endothelial cell IL 1 receptor function are discussed.

Animals↗
PubMed1986

Hormonal regulation of thyrotropin alpha and beta subunit mRNAs.

We have examined the effects of 3,5 3'-triiodo-L-thyronine (T3), dexamethasone, bromocriptine, thyrotropin releasing hormone (TRH) and estrogen on the levels of pituitary alpha and TSH-beta protein and mRNA levels in hypothyroid mice. After 3 days of treatment with T3 (0.5 micrograms/100 g body weight) serum TSH, alpha and TSH-beta levels were 77%, 79% and 44% of control, respectively. Pituitary alpha and TSH-beta mRNA content was estimated by dot blot hybridization of total RNA with 32P-labelled alpha and TSH-beta plasmid probes. There was no change in alpha mRNA after 3 days of T3 treatment but TSH-beta mRNA had decreased to 60% of control. With T3 at 2 micrograms/100 g body weight for 3 days, TSH protein was 27% of control and TSH-beta was undetectable, but there was no change in alpha. TSH-beta mRNA was decreased to 40% of control at 1 day and was barely detectable at 3 days, whereas alpha mRNA was 70% of control at 1 day and 42% at 3 days. Dexamethasone and bromocriptine caused no consistent change in pituitary levels of alpha and TSH-beta mRNA. Treatment with TRH caused small increases in serum TSH and in both alpha and TSH-beta mRNA levels. Estrogen treatment increased serum TSH and subunit levels and TSH-beta mRNA, but not alpha. We conclude that thyroid hormones decrease alpha and beta subunit mRNA levels discordantly in both the hypothyroid pituitary and in thyrotropic tumors and that the suppressive effect of thyroid hormone is the major regulator of TSH.

Animals↗
PubMed1985

Expression of I-region-associated antigen (Ia) and interleukin 1 by subcultured human endothelial cells.

Activation of T cells requires three signals from an antigen-presenting cell: antigen, Ia determinants (HLA-D region determinants in man), and interleukin 1 (IL-1). Recent evidence has suggested that macrophages, dendritic cells, epidermal Langerhan's cells, and endothelial cells can each function as antigen-presenting cells (APC). If these cell types can independently function as APC, they should synthesize Ia determinants and secrete IL-1. To determine if endothelial cells fulfill these requirements, we have propagated human umbilical vein endothelial cells by serial subculture for extended periods of time and assessed Ia expression and IL-1 secretion. The endothelial cells were subcultured for 8 months (approximately 20 subcultures) and were found to display classic morphology and immunofluorescent staining for the endothelial cell-specific marker Factor VIII-related antigen. In a separate paper we have shown that these subcultured endothelial cells can present antigen to T cells in a HLA-D region-restricted fashion (C. R. Wagner, R. M. Vetto, and D. R. Burger, Subcultured human endothelial cells can independently function as fully competent antigen-presenting cells, accepted for publication, Hum. Immunol.). In this paper we present evidence demonstrating that extensively subcultured endothelial cells biosynthesize both HLA-DR and HLA-DS molecules after exposure to T cells and antigen or to a supernatant from antigen-activated T cells. Evidence is also presented that when endothelial cells are cultured in the presence of lipopolysaccharide they secrete a molecule(s) with IL-1 activity as assayed by LBRM-33-IA5 cell line production of interleukin 2.

Antigen-Presenting Cells↗
PubMed1985

Subcultured human endothelial cells can function independently as fully competent antigen-presenting cells.

Recent evidence has suggested that dendritic cells, epidermal Langerhan's cells and endothelial cells (EC) as well as macrophages, fulfill the requirements of antigen-presenting cells. Despite a variety of controls, one weakness in the evidence that these latter cell types can independently serve as antigen-presenting cells is that the cell preparations may contain small numbers of contaminating macrophages or other cell types. The experiments described in this paper are directed towards providing firm evidence that human EC are independently capable of presenting antigen to T cells. EC were isolated from human umbilical veins and maintained continuously by serial subculture for periods of up to 8 months. The subcultured EC displayed classic EC morphology and uniform immunofluorescent staining for Factor VIII-related antigen. The subcultured EC (tested to the 18th subculture) presented both particulate and soluble antigens to macrophage-depleted T cells with an efficiency equivalent to freshly isolated cells. Monoclonal antibodies to HLA-DR and HLA-DS determinants inhibited antigen presentation by either autologous macrophages or EC. In addition, antigen presentation by the subcultured EC was not affected by the macrophage-specific monoclonal antibody Mac-120, which inhibited antigen presentation by autologous macrophages in the same experiments. These results are consistent with human EC being able to independently function as fully competent antigen-presenting cells.

Antibodies, Monoclonal↗
PubMed1984

The mechanism of antigen presentation by endothelial cells.

Endothelial cells line the vessels and lymphatics forming a barrier between circulating T cells and the extravascular tissue site of antigen. We have suggested that circulating T cells recognize antigen on the surface of endothelial cells, resulting in the activation of the endothelium such that the endothelial cells then release the key mediators of a cell-mediated immune response. To test this hypothesis, we have evaluated the extent to which endothelial cells can signal antigen-specific T cell activation. We have shown that cultured endothelial cells are as effective as macrophages in lymphocyte activation and that this activation is HLA-DR restricted. In additional experiments we have established that endothelial cells synthesize both Ia and IL-1 early in the signaling process. To eliminate any possible contribution of other cell types participating in the T cell-endothelial cell interaction, we have shown that cloned endothelial cells present antigen to cloned T cells. Moreover, there appeared to be a preference of selected T-cell populations for different types of antigen presenting cells. These experiments document that endothelial cells are independently competent antigen presenting cells.

Antigen-Presenting Cells↗
PubMed1982

The assessment of anti-idiopathic antibodies as effective immunoregulatory probes in vivo.

In order to increase our understanding of the potential to use anti-idiotypic antibodies as immune modulators in vivo, we extensively analysed influences induced by one such antibody (anti-Id-l) following its administration to animals of different ages, genetic backgrounds, and immunological histories. Id-l is an inter-strain idiotype associated with rat anti-Group A streptococcal carbohydrate antibodies. The intraperitoneal (i.p.) injection of anti-Id-l antibodies, prepared against Id-l+ antibodies from an HPR rat could effectively induce long-term idiotype suppression in all tested strains of rats, regardless of the age at the time of treatment, the RTl haplotype or IgG2c or k-chain allotype. Total anti-streptococcal antibodies were not suppressed by this treatment. Although long-term suppression could be induced at any age, the percentage of animals suppressed following neonatal injections was consistently less than that following adult injections of anti-idiotypic antibodies. In addition, neonatal injections of anti-Id-l or Id-l with anti-Id-l appeared to enhance Id-l production in a minority of the animals. Similar treatment of adult animals never increased Id-l synthesis, suggesting that cells associated with enhanced Id-l production in older animals are either refractory to activation-differentiation signals and/or are sequestered and no longer accessible by i.v. or i.p. routes of administration of the probe. Auto-anti-Id-l immunity induced by immunizing adult rats with heavy, light, F(ab')2 fragments or whole IgG molecules could also induce an Id-l suppressed state. We were not able to induce significant Id-l suppression if animals were immunized with antigen prior to the injection of anti-Id-l. There was evidence, however, that such treatment might lead in time to the development of some idiotype specific suppression.

Aging↗
PubMedDate not supplied

A phospholipase C protocol for phospholipid peroxidation analysis.

A new method has been developed to analyze the primary products of phospholipid peroxidation. The procedure utilizes the ability of phospholipase C to hydrolyze phospholipid hydroperoxides to their corresponding diacylglycerol derivatives. 1-Palmitoyl-2-linoleoylphosphatidylcholine (1P,2L-GPC), 1-stearoyl-2-linoleoylphosphatidylcholine (1S,2L-GPC), and 1-stearoyl-2-arachidonylphosphatidylcholine (1S,2A-GPC) were autoxidized. The diacylglycerol hydroxides derived from the phosphatidylcholine hydroperoxides were separated by reverse-phase high-pressure liquid chromatography (RP-HPLC) and normal-phase high-pressure liquid chromatography (NP-HPLC). 1P,2L-diglyceride (1P,2L-DG) and 1P,2A-DG products were easily separated from 1S,2L-DG and 1S,2A-DG products by RP-HPLC. The linoleate diglyceride oxidation mixture was separated into the 13-trans/cis, 13-trans/trans, 9-trans/cis, and 9-trans/trans isomers by NP-HPLC. Likewise, 1P,2A-DG and 1S,2A-DG oxidation products were resolved into the 15-trans/cis, 15-trans/trans, 12-trans/cis, 11-trans/cis, 9-trans/cis, 8-trans/cis, and 5-trans/cis isomers. In both of the above cases, the 1,2-diacylglycerol isomers could be separated from the 1,3 isomers. Moreover, the diastereomers of the 9-, 8-, and 5-hydroxides could be separated. Each of the diacylglycerol oxidation products was characterized by (1) proton nuclear magnetic resonance (proton NMR), (2) electron ionization-mass spectrometry (EI-MS), and (3) NP-HPLC of the corresponding fatty acids. The diacylglycerol analysis provided the same results for the autoxidation of 1P,2L-GPC as the fatty acid methyl ester analysis. In addition, when 1S,2A-GPC was autoxidized in the presence of 5% alpha-tocopherol, both diastereomers of the 5-hydroxide were observed in the same proportions as the other hydroxides.

Diglycerides↗
PubMedDate not supplied

Conversation versus narration in pre-school children with language impairment.

The study focuses on two elicitation methods for language sampling in children with language impairment: conversation and narration. It has been noted in other studies on different clinical groups that language elicited in different speaking contexts varies in aspects such as MLU, fluency and syntactic complexity. The purpose of this study was to compare genre effects on different aspects of language production in a group of pre-school children with language impairment. The results show that there are differences in language production during conversation compared with narration. Intelligibility and fluency were found to be higher in conversation than in narration, whereas MLU in words was higher in narration. The narrative task elicited more phrasal expansions and grammatical morphemes per utterance than the conversation. However, the children used more complex verb forms in conversation than in narration. The results are discussed in relation to recent research.

Child, Preschool↗
PubMedDate not supplied

Giving the crucial information: performance on a referential communication task in Swedish children with language impairment.

The study focused on the performance of a group of Swedish children with language impairment (LI) on a referential communication task as a step in the investigation of their pragmatic skills. The task entailed choosing a single card from a selection of 16 depicting a face and describing it well enough for the opponent in order for him/her to pick the correct one from his/her identical array of cards laid out behind a barrier. To give an adequate description, the player had to understand that four dimensions had to be described in order for the other person to choose the correct card. The participating children had been part of a previous study on narrative skills in children with LI. A few of them with rather poor language comprehension had shown utterances during story generation judged to be irrelevant to both the listener and the task. In the present study, language comprehension did not significantly correlate to performance on the referential communication task. The participants performed at the level of their peers without LI and there was no significant difference between the amount of relevant or irrelevant information when the children with LI interacted with an adult or with a friend. The results are discussed in relation to recent research.

Case-Control Studies↗
PubMedDate not supplied

Synthesis and antiviral activity of amino acid carbamate derivatives of AZT.

Lipophilic amino acid methyl ester and methyl amide carbamates of 3'-azido-3'-deoxythymidine (AZT) were synthesized and their anti-HIV-1 activity in PBMCs was determined. The methyl amides were more potent (EC50s = 1.8-4.0 microM) than the methyl esters (EC50s = 2.0-20 microM). Carbamate hydrolysis by cell lysates and liberation of AZT was not observed for representative methyl ester or methyl amide AZT carbamates. No evidence of direct inhibition of HIV reverse transcriptase or integrase was observed.

Anti-HIV Agents↗
PubMedDate not supplied

Antiviral nucleoside drug delivery via amino acid phosphoramidates.

Stable and water soluble amino acid phosphomonoester amidates of AZT were synthesized and shown to have potent anti-HIV-1 activity. Intracellular and cell extract metabolism studies revealed that these compounds are likely to be enzymatically converted to the corresponding monophosphates. In addition, we have shown that the half life and tissue distribution of a phosphoramidate of AZT is 5 and 10-fold greater, respectively, than AZT.

Amino Acids↗
PubMedDate not supplied

Cardiac allograft vasculopathy: current concepts, recent developments, and future directions.

Survival after heart transplantation has improved steadily over the past decade, with 1-year mortality rates now less than 15% in most centers. Despite a substantial improvement in early survival, late death has not been significantly impacted. The major cause of late death is due to cardiac allograft vasculopathy, an accelerated form of coronary artery disease. The mechanisms responsible for cardiac allograft vasculopathy are thought to be immunologic; however direct confirmation of this is lacking. Because cardiac allograft vasculopathy is not amenable to traditional therapies for coronary atherosclerosis, to date the only treatment is repeat transplantation. This paper reviews the clinical aspects of cardiac allograft vasculopathy, the recent experimental work, and potential future directions for study.

Animals↗
PubMedDate not supplied

Time course and contact dependence of allogeneic lymphocyte-induced human aortic endothelial cell-derived interleukin-6.

Vascular endothelial cells secrete the pluripotent cytokine interleukin-6, and the induction of this secretion can be regulated by a number of other immune-related cytokines. To determine whether a cellular alloimmunologic response to vascular endothelial cells alters the expression of interleukin-6 production by endothelial cells, we cocultured peripheral blood lymphocytes with a pool of human aortic endothelial cells. In response to the pool of allogeneic human aortic endothelial cells, lymphocytes from 10 separate donors proliferated to varying degrees after 5 days of coculturing. After 20 hours, human aortic endothelial cell-derived messenger RNA coding for interleukin-6 increased an average of 96% after exposure to allogeneic lymphocytes and the amount of biologically active interleukin-6 released into the media increased 69%. The kinetics of human aortic endothelial cell interleukin-6 messenger RNA expression in response to lymphocytes from an additional three donors was determined over a 48-hour period. Human aortic endothelial cell interleukin-6 messenger RNA increased approximately threefold over control, as early as 2 hours after exposure to allogeneic lymphocytes and returned toward control levels by 48 hours. Activation of six additional isolates of lymphocytes with phorbol myristate acetate before exposure to human aortic endothelial cells resulted in an increase in human aortic endothelial cell-derived interleukin-6 bioactivity regardless of whether the cells were in direct contact with the human aortic endothelial cells, but the interleukin-6 level increase was approximately twofold higher in those cocultures where there was direct contact. These data show that allogeneic lymphocytes have the potential of regulating vascular endothelial cell-derived interleukin-6, and direct lymphocyte-endothelial cell contact appears to be required for optimal interleukin-6 induction in this in vitro system.

Aorta↗
PubMedDate not supplied

Temporal reduction in acute rejection after heart transplantation is not associated with a reduction in cell-mediated responses to donor-specific vascular endothelium.

BACKGROUND: Over the first 6 months after clinical transplantation, the incidence of rejection falls despite typically substantial decreases in maintenance immunosuppression. Despite this, chronic vascular rejection, manifested by an accelerated form of coronary artery disease is usually evident by the first annual angiogram and continues to progress over subsequent years. METHODS: To investigate this phenomenon further, peripheral blood mononuclear cells were prepared from blood samples obtained from 42 cardiac allograft recipients at 1 week, 3 months, and 6 months after transplantation and co-cultured with endothelial cells isolated and cultured from the aortas of their specific cardiac allograft donors. Donor-specific alloreactivity was assessed by (1) peripheral blood mononuclear cell proliferation (3H-thymidine incorporation) and (2) up-regulation of endothelial cell major histocompatibility complex class I and class II antigens and ICAM-1 expression (flow cytometry) at all three time points. RESULTS: Over this 6-month period, rejection incidence fell from 0.68 rejections/patient to 0.12 rejection/patient. Cyclosporine dose was reduced from 5.6 +/- 0.3 mg/kg (mean +/- standard error of the mean) to 4.5 +/- 0.2 mg/kg, prednisone dose was reduced from 0.58 +/- 0.08 mg/kg to 0.17 +/- 0.02 mg/kg, and azathioprine remained constant at approximately 2 mg/kg over the 6-month period. Despite this reduction in rejection and immunosuppression, no measure of in vitro donor-specific cell-mediated response to endothelial cells decreased over the 6-month time period. Peripheral blood mononuclear cell proliferation in response to donor-specific endothelial cells was unchanged between 1 week (916 +/- 139 counts/min [cpm]) and 3 months (896 +/- 135 cpm) and increased at 6 months (1738 +/- 243 cpm, p < 0.01). The increase in endothelial cell major histocompatibility complex class II expression in response to recipient peripheral blood mononuclear cells likewise was unchanged between 1 week (42.5 +/- 7.8 mean channel shift [mcs]) and 3 months (34.7 +/- 6.6 mcs) and increased substantially at 6 months (95.4 +/- 17.2 mcs, p < 0.02). The magnitude of the increase in endothelial cell major histocompatibility complex class I antigen and ICAM-1 expression in response to co-culture with recipient peripheral blood mononuclear cells did not change over the 6-month period. CONCLUSIONS: These data suggest an important dichotomy between cell-mediated responses to allograft parenchyma versus those to allograft vasculature and may provide an explanation for progressive vascular disease despite the absence of acute rejection.

Adolescent↗