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E J Shannon

Publications and source records attributed to E J Shannon.

At least 19 recordsLinked to original sources
PubMed2006

Effect of thalidomide on the expression of TNF-alpha m-RNA and synthesis of TNF-alpha in cells from leprosy patients with reversal reaction.

Hypersensitivity reactions called reversal reaction (RR) and erythema nodosum leprosum (ENL) occur in leprosy. They are characterized by an increase in tumor necrosis factor-alpha (TNF-alpha). Thalidomide is an effective treatment for ENL but not RR. Its effectiveness in ENL is attributed to inhibition of TNF-alpha, and this does not explain its failure to treat RR. We assessed thalidomide's effect on TNF-alpha in RR. Mononuclear cells from RR and non-RR patients and healthy individuals were treated with thalidomide and M.leprae (AFB), a cytosol fraction of M. leprae or Dharmendra lepromin. Thalidomide suppressed TNF-alpha, but when some RR patients' cells were stimulated with AFB, it enhanced TNF-alpha.

Adolescent↗
PubMed2005

Effects of thalidomide on intracellular Mycobacterium leprae in normal and activated macrophages.

Thalidomide is an effective drug for the treatment of erythema nodosum leprosum (ENL). ENL is an inflammatory reaction that may occur in multibacillary leprosy patients. Its cause(s) as well as the mechanism of thalidomide in arresting this condition are not fully understood. It has been suggested that ENL is an immune complex-mediated hypersensitivity precipitated by the release of Mycobacterium leprae from macrophages. The released antigen may complex with precipitating antibodies, initiating complement fixation and the production of inflammatory cytokines like tumor necrosis factor alpha (TNF-alpha). Thalidomide has been shown in vitro to reduce antigen- or mitogen-activated macrophage production of TNF-alpha. We investigated if thalidomide could also influence the viability of intracellular M. leprae. Mouse peritoneal macrophages were infected with M. leprae, activated with gamma interferon and endotoxin, or nonactivated, and treated with thalidomide. Intracellular bacilli were recovered, and metabolic activity was assessed by a radiorespirometric procedure. Thalidomide did not possess antimicrobial action against M. leprae in normal and activated host macrophages. This suggests that thalidomide does not retard the release of mycobacterial antigens, a possible prelude or precipitating factor for ENL. A distinct sequence of events explaining the mechanism of action for thalidomide's successful treatment of ENL has yet to be established.

Animals↗
PubMed2004

Stabilization of red blood cell membranes by thalidomide in vitro.

The anti-inflammatory effect of thalidomide has been well established. The mechanism of this anti-inflammatory action is still not completely understood. Certain drugs exert their anti-inflammatory action by stabilizing the membranes of polymorphonuclear neutrophils (PMN) thereby reducing the production of reactive oxygen intermediates. We evaluated the effect of thalidomide on cell membranes by using red blood cells (RBC), PMN and the monocyte-like cell line THP-1. Osmotic fragility of RBC showed that in vitro, thalidomide stabilized the membrane of RBC from plasma free blood; whereas, it did not affect RBCs from whole blood. Red blood cells taken from subjects before and after ingestion of thalidomide were not affected after exposure to different concentrations of hypotonic NaCl solution. Thalidomide did not affect the membrane stability of PMNs as well as THP-1 in a significant manner. These data suggest that the anti-inflammatory mechanism of thalidomide is not related to events associated with the oxidative burst of PMNs or monocytes.

Adult↗
PubMed2003

Thalidomide does not modify the ability of cells in leprosy patients to incorporate [3H]-thymidine when incubated with M. leprae antigens.

The immune response in reversal reaction, (RR) and in erythema nodosum leprosum (ENL) is characterized in vitro by an enhancement in lymphocyte blast transformation against M. leprae. As thalidomide is an effective treatment for ENL, this study assessed the effect of this drug on these phenomena. Mononuclear cells from patients attending the clinic at ALERT and from healthy staff were cultured for 5 days with integral M. leprae (IMl), or a modified Dharmendra antigen (Dhar), or PPD from M. tuberculosis. In one set of cultures, thalidomide was added once at the initiation of the culture; in the other set thalidomide was added a second time (2x), 18 h prior to harvesting the cells. The mononuclear cells, in the absence of thalidomide, from healthy staff, borderline tuberculoid patients (BT) and BT patients in RR (BT/RR) incorporated [3H]-thymidine best when cultured with PPD > Dhar > M. leprae. The cells from patients with ENL did not respond well to the M. leprae antigens. Thalidomide (2x) enhanced proliferation to Dhar in the BTRR group (Wilcoxon signed rank test, P < 0.05). No significant changes occurred for the other groups. Comparing PPD-stimulated cells treated with thalidomide once to those treated with thalidomide twice, thalidomide (2x) suppressed incorporation of [H3]-thymidine by the PPD-stimulated (P < 0.05) as well as IMl-stimulated (P < 0.05) cells in the healthy staff group. In the Dhar-stimulated cells from the healthy staff thalidomide significantly suppressed TNF-alpha (P < 0.05). A mixed effect was seen within and between the other groups, but there was a trend for thalidomide to suppress TNF-alpha induced by the M. leprae, Dhar and PPD antigens.

Adolescent↗
PubMed2000

Randomized safety studies of intravenous perflubron emulsion. II. Effects on immune function in healthy volunteers.

Particle size distribution is a major determinant of particle clearance by the mononuclear phagocytic system and the potential for concomitant activation of resident macrophages. To test the safety of a second-generation perflubron-based emulsion (60% perfluorocarbon [PFC] wt/vol; Oxygent [Alliance Pharmaceutical Corp., San Diego, CA]) with a small mean particle size, two parallel, randomized, double-blinded, placebo-controlled studies were conducted in 48 healthy volunteers (n = 24 per study). The study described herein focuses on safety concerning immune function. The primary endpoint was defined prospectively as delayed hypersensitivity skin test responses with lymphocyte proliferative responses to mitogenic stimulation providing a secondary measure for changes in cell-mediated immunity. Subjects received either perflubron emulsion IV (1.2 g PFC/kg or 1.8 g PFC/kg) or saline (3 mL/kg) control. Perflubron emulsion had no effect on delayed hypersensitivity skin reactions, lymphocyte proliferative potential, circulating immunoglobulins, complement activation, or plasma levels of the inflammatory cytokines, tumor necrosis factor-alpha, interleukin-1 alpha, and interleukin-1 beta. Perflubron emulsion was generally well tolerated, although there was a dose-dependent increase in minor flu-like symptoms in the perflubron treatment groups at 24 h after dosing. Increased serum levels of interleukin-6 were observed in those subjects exhibiting febrile responses. The clinical safety profile of perflubron emulsion supports its continued investigation as a temporary oxygen carrier in surgical patients to reduce exposure to allogeneic blood transfusion.

Adolescent↗
PubMed1997

Immunomodulatory assays to study structure-activity relationships of thalidomide.

Thalidomide, which has a long history of tragedy because of its ability to cause severe birth defects, is very effective in alleviating erythema nodosum leprosum in leprosy patients and aphthous ulcers in AIDS patients. The causes of these inflammatory diseases and the mechanism by which thalidomide diminishes them are unknown. It has been suggested that modulation of the immune response plays an important role. We found that thalidomide exerts immunomodulatory activity in three bioassays. It suppresses an IgM plaque forming cell response in mice injected with sheep erythrocytes: it inhibits TNF-alpha production by LPS stimulated human mononuclear cells: and it enhances IL-2 production by Con-A stimulated human mononuclear cells. We employed these bioassays to compare the activity of 15 analogs of thalidomide with thalidomide itself. Eight of the compounds were derivatives of the glutarimide moiety of thalidomide and the others were phthalimide or derivatives of the phthalimide moiety of thalidomide. N-hydroxyphthalimide, a simple derivative of phthalimide, was more effective than thalidomide and was also the most effective of the compounds assayed in suppressing the IgM plaque and TNF-alpha responses, but it did not enhance the IL-2 response, instead, it significantly suppressed it.

Adjuvants, Immunologic↗
PubMed1997

Hydrolysis of thalidomide abrogates its ability to enhance mononuclear cell synthesis of IL-2 as well as its ability to suppress the synthesis of TNF-alpha.

Thalidomide is effective in the treatment of inflammatory conditions like erythema nodosum leprosum in leprosy patients, and aphthous ulcers in AIDS patients. Its mechanism of action is uncertain and reports of its effect on the synthesis of inflammatory cytokines such as IL-2 and TNF-alpha are contradictory. As thalidomide is labile to spontaneous hydrolysis at pH 7.4, studies were carried out to explore the effects of deliberate hydrolysis or the ability of thalidomide to modulated cytokine production by human mononuclear cells stimulated in vitro with Staphylococcal enterotoxin A (SEA)(IL-2) or lipopolysaccharide from Salmonella minnesota (LPS)(TNF-alpha). Unhydrolyzed thalidomide at 4.0 micrograms/ml consistently enhanced the synthesis of IL-2 in SEA-stimulated cells, and suppressed the synthesis of TNF-alpha in LPS-stimulated cells; whereas, hydrolyzed thalidomide had no enhancing effect on SEA stimulated-cell synthesis of IL-2 or suppressive effect on LPS stimulated-cell synthesis of TNF-alpha. These findings demonstrate that thalidomide's ability in vitro to enhance IL-2 and to suppress TNF-alpha in stimulated cells is dependent on the intact molecule and underscore the necessity to employ thalidomide under appropriate physicochemical conditions.

Biotransformation↗
PubMed1997

Effect of thalidomide on apoptosis of lymphocytes and neutrophils.

Thalidomide causes congenital anomalies and it is immunomodulatory. These properties could be explained by an ability to alter the orderly process of programmed cell death during embryogenesis and modulation of apoptosis of lymphoid and/or myeloid cells in the immune response. Apoptosis of lymphoid and myeloid cells was studied by measuring the percentage of cells capable of excluding propidium iodide and expressing phosphatidylserine on their outer membrane. In addition, expression of Fc gamma RIII (CD16) was used to assess neutrophil apoptosis. Thalidomide did not affect the rate of apoptosis of CTLL-2 cells deprived of, or supplemented with, IL-2; of T-cells (mitogen-stimulated or resting) or of neutrophils. However, neutrophils obtained from HIV-infected patients treated with thalidomide showed reduced expression of CD16, a surrogate marker for apoptosis of neutrophils. Thalidomide's effect on neutrophil apoptosis in vivo warrants further investigation.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

Thalidomide can be either agonistic or antagonistic to LPS evoked synthesis of TNF-alpha by mononuclear cells.

The effect if thalidomide on tumor necrosis factor alpha (TNF-alpha) produced in vitro by lipopolysaccharide (LPS) stimulated human cells was investigated. In cultures of LPS stimulated human mononuclear cells enriched for adherent cells and in cultures of LPS stimulated human monocytes of the cell line-THP-1, thalidomide enhanced the synthesis of TNF-alpha. When cultures of unfractionated peripheral blood mononuclear cells were stimulated with LPS, thalidomide decreased the synthesis of TNF-alpha. Depending on the type of cells stimulated with LPS in vitro, thalidomide, at concentrations achieved in vivo, can either enhance or suppress the synthesis of TNF-alpha.

Cell Adhesion↗
PubMed1995

Thalidomide increases the synthesis of IL-2 in cultures of human mononuclear cells stimulated with Concanavalin-A, Staphylococcal enterotoxin A, and purified protein derivative.

Thalidomide significantly increases the quantity of extracellular IL-2 in cultures of human mononuclear cells stimulated with mitogens or antigen. Cells from 7 donors exposed for 2 h to 4.0 micrograms/ml of thalidomide and stimulated for 16-18 h with 20 micrograms/ml of Concanavalin-A (Con-A) averaged producing 187 +/- 49% more IL-2 than cells stimulated with Con-A alone. In similar experimental procedures and comparisons the pg/ml of IL-2 secreted by thalidomide-treated cells from five donors stimulated with 50 ng/ml of Staphylococcal enterotoxin A (SEA) increased by 159 +/- 32%, and the pg/ml of IL-2 secreted by thalidomide-treated cells from 2 donors stimulated with 5.0 micrograms/ml of purified protein derivative of Mycobacterium tuberculosis increased by 120 +/- 4%. Thalidomide also significantly increases the quantity of intracellular IL-2 in cells stimulated with mitogens. Cells exposed to thalidomide and stimulated with Con-A had an increase in intracellular IL-2 of 130% after 8 h and 157% after 12 h in culture; cells stimulated with SEA had an increase in intracellular IL-2 of 120% after 8 h and 182% after 12 h in culture. Thalidomide did not alter the percent of lymphocytes expressing the alpha-chain of IL-2 receptor, nor did it significantly increase incorporation of [3H]thymidine by cells.

Cells, Cultured↗
PubMed1995

Early detection of rifampin in human nerve tissue after an oral dose of 600 milligrams.

Rifampin in picogram quantities inhibited the ability of Mycobacterium bovis 44 BCG P3 to release 14CO2 from the oxidation of [14C]palmitic acid. By using these mycobacteria in a bioassay, samples of serum and posterior tibial nerve were assayed for inhibitory concentrations of rifampin. Within 8 to 12 h after ingestion of 600 mg of rifampin, the drug was detected in eight patients in concentrations ranging from 0.52 to 4.1 micrograms/ml in serum and in concentrations ranging from 0.6 to 6.3 ng/mg in posterior tibial nerve fiber tissue.

Adolescent↗
PubMed1995

Analysis of T-cell and B-cell responses to recombinant M. leprae antigens in leprosy patients and in healthy contacts: significant T-cell responses to antigens in M. leprae nonresponders.

The recognition of a panel of recombinant Mycobacterium leprae antigens by T cells and B cells from 29 borderline tuberculoid/tuberculoid (BT/TT) and 18 lepromatous leprosy (LL) patients and from 21 healthy controls (HC) in leprosy-endemic regions of Ethiopia was examined. All 11 antigenic molecules tested (including M. leprae hsp 10, hsp18, hsp65 and several novel M. leprae antigens) were shown to be recognized by T cells, but clear quantitative differences existed between reactivities induced by individual antigens. Similar quantitative differences were observed when antibody responses to hsp10 and hsp65 antigens were determined. No associations were found between the antigen-specific responses and the subject status of either BT/TT and LL patients or HC. Fifteen percent of the patients who were nonresponsive to sonicates of M. leprae showed significant T-cell responses to one or more individual M. leprae antigens. This indicates that M. leprae constituents other than the proteins tested are responsible for the M. leprae-specific nonresponsiveness in these patients, which may be exploited for the design of vaccines or immunotherapeutic modalities aimed at inducing M. leprae-specific immunity in nonresponders.

Antibodies, Bacterial↗
PubMed1994

Thalidomide does not perturb CD2, CD4, CD5, CD8, HLA-DR, or HLA-A, B, C molecules in vitro on the membranes of cells with immune potential.

Thalidomide dramatically relieves the signs and symptoms of erythema nodosum leprosum (ENL). ENL is an acute inflammatory complication of lepromatous leprosy. The cause(s) of ENL as well as the mechanism of action of thalidomide in arresting ENL are unknowns. It has been suggested that ENL is the consequence of a transient activation of a cell-mediated-immune (CMI) response to Mycobacterium leprae. To initiate a CMI response, an interaction between adhesion and/or signal transducing molecules on T-cells and molecules on antigen presenting cells would occur. An alteration, induced by thalidomide, of one or more of the molecules on T-cells or antigen presenting cells that are essential to maintaining the reactive state of ENL, could explain Thalidomide's ability to attenuate ENL. Thalidomide did not modify: (a) adhesion and/or signal transducing molecules such as CD2, CD4, CD5 and CD8, or (b) molecules that facilitate antigen presentation such as HLA-DR, HLA-A, HLA-B, or HLA-C.

Antibodies, Monoclonal↗
PubMed1994

Titration of numbers of human-derived Mycobacterium leprae required to progressively oxidize 14C-palmitic acid and release 14CO2.

Mycobacterium leprae was isolated from skin-punch biopsies of 2 untreated lepromatous leprosy patients. The bacteria were enumerated, diluted 10-fold and cultured in Middlebrook 7H9 medium supplemented with albumin, dextrose, catalase and 14C-palmitic acid. The cultures were incubated at 33 degrees C in a modified Buddemeyer radiorespiratory detection vessel. Those cultures containing at least 10(7) mycobacteria demonstrated a progressive evolution of 14CO2.

Carbon Dioxide↗
PubMed1993

Lepromin responses in recipients of a candidate antileprosy bacterin vaccine (WHO-IMMLEP Mycobacterium leprae killed preparation) in the USA.

BACKGROUND: Identification of the nine-banded armadillo as a potential source of massive numbers of Mycobacterium leprae led to the development of a candidate bacterin vaccine for possible immunoprophylaxis. METHODS: Volunteers were from a leprosy-hypoendemic, nonBCG-using area (USA). They had been vaccinated intradermally 3 years earlier with a candidate antileprosy bacterin vaccine of irradiated and autoclaved Mycobacterium leprae obtained from experimental nine-banded armadillos. They were tested for dermal responsiveness to standard lepromin A. RESULTS: Values for induration and erythema appeared slightly greater for the vaccinated group; however, the differences were not statistically significant, indicating no appreciable 'anamnestic' effect on either Fernandez (early) or Mitsuda (late) reactions after 3 years. CONCLUSIONS: Because previous studies had demonstrated that administration of this bacterin produced no humoral changes, it now appears less probable that laboratory methods will be of much help in assessing even possible effectiveness of such vaccination.

Bacterial Vaccines↗
PubMed1992

Thalidomide's effectiveness in erythema nodosum leprosum is associated with a decrease in CD4+ cells in the peripheral blood.

Thalidomide is well documented as being an effective drug in the treatment of erythema nodosum leprosum (ENL). The mechanism of action of thalidomide in ENL as well as the pathogenesis of ENL are yet to be fully determined. Lepromatous leprosy patients experiencing ENL have been reported to have an increase in the ratio of CD4+ to CD8+ cells in their blood and ENL skin lesions. Thalidomide has been shown to cause a decrease in the ratio of CD4+ to CD8+ lymphocytes in the blood of healthy males. This decrease was due to a significant reduction in the numbers of Cd4+ lymphocytes and an apparent increase in the numbers of CD8+ lymphocytes. In this study, thalidomide's effectiveness in halting chronic ENL and arresting a relapse into ENL was consistently associated with a decrease in the numbers of CD4+ lymphocytes in the blood of 2 male lepromatous leprosy patients.

Adult↗