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Biomedical subjects

J J Ellner

Publications and source records attributed to J J Ellner.

At least 73 records · Page 4Linked to original sources
PubMed1997

Activity of new quinolones against intracellular Mycobacterium avium in human monocytes.

The ability to inhibit the in-vitro growth of mycobacteria within human monocytes is a useful screening assay for novel chemotherapeutic agents. In this study the MICs of a panel of new quinolones were determined by the broth microdilution method for two strains of Mycobacterium avium. Sixteen such compounds with MIC90s ranging from 2 to >32 mg/L were subsequently selected for the 7 day monocyte assay using ciprofloxacin for comparison. The degree of inhibition of intracellular growth correlated with the MICs. PD 139586, PD 143289, PD 135144, PD 119421 and PD 131575 were the most active new agents with activities superior to those of ciprofloxacin and sparfloxacin.

Anti-Infective Agents↗
PubMed1997

Two-step tuberculin skin testing in HIV-infected persons in Uganda.

Identifying persons infected with both human immunodeficiency virus (HIV) and Mycobacterium tuberculosis (MTB) is often difficult because of the reduced sensitivity of tuberculin skin testing in HIV-infected persons. To determine the value of two-step tuberculin skin testing (TTST) as a method of increasing the sensitivity of tuberculin skin testing in HIV-infected persons, a consecutive sample of 58 HIV-infected persons being screened for a TB preventive therapy trial in Uganda with an initial purified protein derivative (PPD) response < 5 mm completed two-step tuberculin and candida skin testing. The mean change in PPD size between the two tests, placed a mean of 8 d apart, was +2.1 mm (SD 4.4 mm, range -4 to +16 mm). Seventeen subjects (29%) had a boosted response (PPD1 < 5 and PPD2 > or = 5). In a multiple logistic regression model, boosted responses were independently associated with a CD4 count between 200 and 500 microl(-1) (p = 0.02) and a higher body mass index (p = 0.05). TTST may be valuable in identifying MTB infection and in preventing misclassification of boosted responses as skin test conversions in HIV-infected persons, especially persons with CD4 counts between 200 and 500 microl(-1) from areas with a high prevalence of MTB infection or from areas with a low prevalence of MTB infection who have other risk factors for MTB infection.

AIDS-Related Opportunistic Infections↗
PubMed1997

Risk factors for adverse drug reactions during thiacetazone treatment of pulmonary tuberculosis in human immunodeficiency virus infected adults.

SETTING: Prospective randomised clinical trial comparing the safety and efficacy of rifampicin- and thiacetazone-containing regimens in human immunodeficiency virus (HIV)-infected adults with pulmonary tuberculosis (TB) at the National Tuberculosis Treatment Centre, Kampala, Uganda. OBJECTIVE: To assess demographic, clinical and laboratory risk factors associated with toxicity during treatment with streptomycin, thiacetazone and isoniazid (STH) of HIV-1 infected adults with pulmonary TB. DESIGN: Nested case-control study of all subjects randomized to the STH treatment arm. Baseline demographic, clinical, microbiological, hematological and radiographic characteristics were compared between subjects who developed and those who did not develop adverse drug reactions (ADR). RESULTS: Of the 90 subjects randomized to STH, 13 developed ADR yielding an incidence rate of 19.6 events per 100 person years of observation (PYO). Eleven of the 13 ADR were cutaneous hypersensitivity reactions, including one fatal case of Stevens-Johnson syndrome. Eight of 13 patients who developed ADR were tuberculin anergic, compared to 12 of 77 patients who did not develop ADR (P < 0.001). An absolute lymphocyte count below 2000 cells/mm3 was also associated with ADR (P = 0.02). CONCLUSION: Initial anergy to tuberculin and lymphocytopenia, markers of advanced HIV infection and immunosuppression, were associated with increased risk for adverse drug reactions during STH chemotherapy.

AIDS-Related Opportunistic Infections↗
PubMed1997

Risk factors for relapse in human immunodeficiency virus type 1 infected adults with pulmonary tuberculosis.

SETTING: A study conducted by the Uganda-Case Western Reserve University Research Collaboration in Kampala, Uganda, a country with high incidence rates of tuberculosis (TB) and human immunodeficiency virus type 1 (HIV-1) infection. OBJECTIVE: To assess clinical, microbiologic and radiographic factors associated with risk for relapse in HIV-infected adults treated for initial episodes of pulmonary TB. DESIGN: Nested case-control study within a randomized prospective clinical trial comparing the safety and efficacy of thiacetazone- and rifampicin-containing regimens for TB treatment in HIV-infected adults. RESULTS: The analysis was based on 119 patients who completed therapy. Median follow-up for all subjects was 22.3 months. Ten patients relapsed a median of 12.7 months after the end of therapy; seven of these were initially treated with the thiacetazone (T)-containing regimen. Each relapse case was matched to four controls by length of follow-up after initial TB treatment. In a univariate analysis risk for relapse was associated with treatment with the T-containing regimen (OR = 4.2, P = 0.08), age > or = 30 yrs (OR = 2.9, P = 0.16), and irregular compliance (OR = 3.6, P = 0.1). Baseline anergy on Mantoux tuberculin skin testing, cavitary disease, radiographic extent of disease and sputum bacillary burden, two month culture negativity, and residual cavitary disease at the end of treatment did not differ between relapses and controls. CONCLUSION: Older HIV-1 infected patients, those with poor treatment compliance, and those being treated with T-containing regimens, may be at increased risk for relapse after TB treatment and require closer post-treatment surveillance. Risk for relapse in HIV-infected adults with pulmonary TB after treatment with a nine month rifampicin-containing regimen was low (3.1 per 100 person-years observation) compared with those treated with a thiacetazone-containing regimen (10.1 per 100 person-years observation).

AIDS-Related Opportunistic Infections↗
PubMed1997

Immune response profile in patients with active tuberculosis in a BCG vaccinated area.

Tuberculosis patients with pulmonary (N = 95) or lymph node disease (N = 23) were assessed for Th1 responses (PPD skin test and lymphocyte blastogenic and interferon gamma) and Th2 responses (polyclonal and antigen specific IgE). Skin test responses to PPD and lymphocyte proliferative responses to crude mycobacterial antigens (PPD, culture filtrate and sonicate) and recall antigens (tetanus toxoid and streptolysin O) were significantly suppressed (p < 0.001) in patients with pulmonary disease compared to endemic controls. However, mitogen (phytohemagglutinin)-stimulated responses were comparable in patients and controls. Polyclonal and antigen specific (M. tuberculosis culture filtrate) IgE responses which are considered to be surrogate markers for Th2 responses were significantly higher in patients with pulmonary disease compared to healthy endemic controls (Mann Whitney analysis p < 0.01). Patients with lymph node disease showed strong Th1 responses but did not show significant responses for either polyclonal or antigen specific IgE. Thus overall suppression of T cell memory response was observed only in patients with pulmonary disease but not in patients with lymph node disease suggesting that sequestration of antigen in different compartments leads to differential activation of Th1 and Th2 responses. PPD skin test responses were highly positive in endemic controls (47% positive) and household contacts (86% positive). Furthermore, PPD positivity decreased with disease severity. Therefore PPD positivity in a BCG vaccinated TB endemic area cannot be used as a diagnostic marker for active tuberculosis particularly in advanced disease.

Antibodies, Bacterial↗
PubMed1996

Induction of monocyte expression of tumor necrosis factor alpha by the 30-kD alpha antigen of Mycobacterium tuberculosis and synergism with fibronectin.

Native 30-kD antigen, also known as alpha antigen, is a fibronectin-binding protein that is secreted by live Mycobacterium tuberculosis. This antigen may play an important biological role in the host-parasite interaction since it elicits delayed type hypersensitivity response and protective immunity in vivo and T lymphocyte blastogenesis and IFN-gamma production in vitro. In the present study, we show that, TNF-alpha protein is produced in monocyte culture supernatants in response to 30-kD antigen and the level is as high as that to purified protein derivative of M. tuberculosis. This stimulatory effect was not due to contamination with either bacterial lipopolysaccharide or mycobacterial lipoarabinomannan. The preincubation of monocytes with plasma fibronectin significantly enhanced the release of TNF-alpha into the culture supernatants in response to 30-kD antigen. This effect was blocked by polygonal antibody to plasma fibronectin. In contrast, the monocytic cell line U937 failed to release TNF-alpha protein in the culture supernatants in response to 30-kD antigen with or without preincubation with plasma fibronectin. To determine whether this observation was due to differential binding of the 30-kD to fibronectin on these cells, a cell based ELISA was used. Pretreatment of monocytes with fibronectin enhanced their binding of the 30-kD antigen. U937 cells bound the 30-kD antigen weakly with or without fibronectin pretreatment. These results indicate that 30-kD antigen which is a known secretary antigen of M. tuberculosis is a stimulus for human monocytes to express TNF-alpha and that stimulatory effect may be mediated through plasma fibronectin.

Antigens, Bacterial↗
PubMed1996

Delayed tuberculin reactivity in persons of Indochinese origin: implications for preventive therapy.

OBJECTIVES: To 1) study a variant delayed reaction to tuberculin testing as a way to enhance screening for tuberculosis among high-risk persons and 2) correlate the delayed reaction with lymphocyte blastogenesis. DESIGN: Cross-sectional study. SETTING: 2 public health department clinics in North Carolina. PARTICIPANTS: 121 adults who had recently emigrated from Vietnam to North Carolina and who were ethnic Vietnamese and ethnic Dega, a minority population group from the central highlands region of Vietnam. MEASUREMENTS: Medical history, physical examination, laboratory evaluation, and standard purified protein derivative (PPD) testing (Mantoux method). Skin test results were read at 72 hours and again at 6 days. Variant reactivity was defined as induration of less than 10 mm at 72 hours that, when reassessed at 6 days, had increased in size to 10 mm or greater. Persons with negative (n=54) and variant (n=32) PPD results also had booster testing at 10 to 12 weeks. Serum samples were obtained from 57 participants for lymphocyte blastogenesis studies. RESULTS: 26% of participants had variant tuberculin reactivity. Variant reactivity was strongly associated with booster positivity: Sixty-five percent of persons with variant PPD results had booster positivity compared with 16% of persons with negative PPD results (P<0.001). The lymphocyte blastogenesis response of persons with variant PPD results was between the response of persons with negative PPD results and that of persons with positive PPD results. CONCLUSION: Variant reactivity in this high-risk group was a predictor of booster positivity. Together with the blastogenic response pattern, this association strongly suggests that variant reactivity has a high positive predictive value for tuberculous infection. Clinicians should incorporate these findings into their approach for choosing candidates for preventive therapy.

Adult↗
PubMed1996

Cross-modulation by transforming growth factor beta in human tuberculosis: suppression of antigen-driven blastogenesis and interferon gamma production.

In tuberculosis, Mycobacterium tuberculosis (MTB)-stimulated T-cell responses are depressed transiently, whereas antibody levels are increased. Lymphoproliferative responses of peripheral blood mononuclear cells (PBMCs) from Pakistani tuberculosis (TB) patients to both mycobacterial and candidal antigens were suppressed by approximately 50% when compared to healthy purified protein derivative (PPD)-positive household contacts. Production of interferon gamma (IFN-gamma) in response to PPD also was depressed by 78%. Stimulation with PPD and the 30-kDa alpha antigen of MTB (30-kDa antigen) induced greater secretion of transforming growth factor beta (TGF-beta), but not interleukin 10 (IL-10) or tumor necrosis factor alpha (TNF-alpha), by PBMCs from TB patients compared to healthy contacts. The degree of suppression correlated with the duration of treatment; patients treated for <1 month had significantly lower T-cell blastogenesis and IFN-gamma production and higher levels of TGF-beta than did patients treated for >1 month. Neutralizing antibody to TGF-beta normalized lymphocyte proliferation in response to PPD, partially restored blastogenesis to candidal antigen, and significantly increased PPD-stimulated production of IFN-gamma in TB patients but not in contacts. Neutralizing antibody to IL-10 augmented, but did not normalize, T-cell responses to both PPD and candida in TB patients and candidal antigen in contacts. TGF-beta, produced in response to MTB antigens, therefore plays a prominent role in down-regulating potentially protective host effector mechanisms and looms as an important mediator of immunosuppression in TB.

Antigens, Bacterial↗
PubMed1996

Immune activation, allergic drug toxicity and mortality in HIV-positive tuberculosis.

SETTING: Tuberculosis Treatment Center, Kampala, Uganda. OBJECTIVE: HIV-1 affects outcome in pulmonary tuberculosis (TB). Immune mechanisms triggered by Mycobacterium tuberculosis may lead to increased HIV expression and accelerated disease progression. This study was conducted to correlate serum levels of markers of immune activation with mortality and drug toxicity in HIV + TB. DESIGN: Substudy of a randomized clinical trial of streptomycin-thiacetazone-isoniazid (STH) vs. rifampin-isoniazid-pyrazinamide (RHZ) in HIV + TB. RESULTS: Neopterin > or = 14 ng/ml, TNF-alpha receptors > or = 6.5 ng/ml, and negative skin test were independently associated with increased mortality (P < 0.01). Among STH-treated subjects, dermatologic toxicity and mortality were respectively 13- and 6.3-fold more likely to occur in subjects with elevated neopterin (P < 0.05), although these two adverse events occurred independently. Activation markers increased from baseline after 2 months of therapy with the less rapidly bactericidal STH regimen, whereas they declined in those treated with RHZ, suggesting a relationship with continued mycobacterial replication. CONCLUSIONS: Immune activation in HIV + TB is associated with shortened survival and increased risk of drug toxicity. HIV + TB patients with elevated serum neopterin should be treated with a rapidly-bactericidal drug regimen which does not include thiacetazone.

AIDS-Related Opportunistic Infections↗
PubMed1996

Generalized immune activation in pulmonary tuberculosis: co-activation with HIV infection.

Parameters of immune activation/differentiation were studied in a group of newly diagnosed HIV- and HIV+ pulmonary tuberculosis (TB) patients. Compared with controls, HLA-DR expression on both CD4 and CD8 T cells from the HIV- TB patients was approximately doubled; HLA-DR on T cells from the HIV+ group was tripled. The monocytes from both groups of patients expressed abnormally high levels of the Fc gamma receptors I and III. Serum levels of tumour necrosis factor-alpha (TNF-alpha), neopterin and beta 2-microglobulin were increased in HIV- and even more so in HIV+ TB patients. The expression of HLA-DR on T cell subsets and of Fc gamma R on monocytes correlated with each other, but not with serum activation markers. This pattern of non-specific activation during TB infection may be associated with enhanced susceptibility to HIV infection.

Adult↗
PubMed1996

Evidence against a role for interleukin-10 in the regulation of growth of Mycobacterium avium in human monocytes.

Interleukin-10 (IL-10) inhibits intracellular Mycobacterium avium killing by cytokine-activated murine macrophages and may have a role in pathogenesis. Cytokine activities in supernatants of M. avium-infected human monocytes were maximal at 6-24 h for tumor necrosis factor (TNF)-alpha and 24-48 h for IL-10. TNF-alpha and IL-10 production increased with increasing M. avium-to-monocyte infection ratios (20:1 to 200:1). TNF-alpha production by monocytes infected with smooth, domed, and opaque organisms at 200:1 exceeded that of monocytes infected with smooth, flat, and transparent M. avium (P < .01). IL-10 induction demonstrated considerable strain-to-strain variability and did not correlate with intracellular M. avium growth. IL-10 significantly inhibited TNF-alpha, IL-1 beta, and IL-6 production by M. avium-infected monocytes. Coculturing monocytes with IL-10 after M. avium infection did not affect intracellular M. avium growth. Differential induction of TNF-alpha may be a factor in the intracellular growth of M. avium in human monocytes. IL-10, however, played no apparent role in pathogenicity in this model.

Base Sequence↗
PubMed1996

Pentoxifylline therapy in human immunodeficiency virus-seropositive persons with tuberculosis: a randomized, controlled trial.

Macrophage activation and tumor necrosis factor-alpha (TNF-alpha) production are critical in tuberculosis immunity but may result in increased human immunodeficiency virus (HIV) expression and accelerated HIV disease progression in HIV-infected persons. Pentoxifylline inhibits expression of TNF-alpha and HIV. A double-blind, placebo-controlled study of adjunctive therapy with pentoxifylline (1800 mg/day) as a timed-release formulation was done in Ugandan HIV-infected patients with pulmonary tuberculosis. Subjects had early HIV disease (mean CD4 cell count, 380/microL) and did not receive other antiretroviral drugs. Pentoxifylline resulted in decreased plasma HIV RNA and serum beta 2-microglobulin and, in a subset of moderately anemic patients, improved blood hemoglobin levels. Trends were noted toward reduced TNF-alpha production in vitro and improved performance scores, but these did not reach statistical significance. No effect was noted on body mass, CD4 cell count, or survival. Additional studies of more potent TNF-alpha inhibitors in HIV-positive subjects with tuberculosis are warranted.

Adult↗
PubMed1996

Induction of prostaglandin E2 by human monocytes infected with Mycobacterium avium complex--modulation of cytokine expression.

Prostanoids, including prostaglandin E2 (PGE2), suppress macrophage effector functions against Mycobacterium tuberculosis. PGE2 production by monocytes infected with Mycobacterium avium complex (MAC) and its effects on intracellular mycobacterial growth were examined. Freshly obtained monocytes from healthy subjects were stimulated with lipopolysaccharide or 10(7) organisms/mL of 4 MAC strains. PGE2 production in monocyte supernatants peaked at 48 h. Significantly higher levels of PGE2 were produced by monocytes infected with the mixed rough-smooth, flat, and transparent (SmT) morphotype strain 86m2096 (26.8 +/- 5.2 ng/mL) than by the more virulent LR114 SmT morphotype strain (2.4 +/- 0.6 ng/mL; P < .05, paired t test). When infected monocytes were incubated with 1 microgram/mL indomethacin (IM) for 2 days and then further stimulated with interferon-gamma, no effect on intracellular MAC growth was evident. IM increased tumor necrosis factor-alpha (1.7 +/- 0.4 vs. 2.3 +/- 0.3 ng/mL; P = .005, paired t test) but not interleukin-1 beta (8.2 +/- 1.7 vs. 8.7 +/- 2.1 ng/mL, P = .34) production by monocytes stimulated with lipopolysaccharide. These data suggest that MAC-induced PGE2 expression may modulate cytokine production and intracellular parasitism.

Adult↗
PubMed1996

Comparison of the activity of fluoroquinolones against Mycobacterium avium in cell-free systems and a human monocyte in-vitro infection model.

Mycobacterium avium frequently causes disseminated infection in advanced AIDS. Some quinolones including ciprofloxacin and sparfloxacin have anti-M. avium activity in cell-free systems in vitro. Acidic conditions within macrophages and variable intracellular drug penetration and compartmentalization may, however, alter the susceptibility of M. avium to these antimicrobial agents in human tissues. We, therefore, tested the activities of 47 quinolones against M. avium in a human monocyte infection model using ciprofloxacin susceptible (MIC = 0.25 mg/L) and resistant (MIC = 4 mg/L) patient isolates. Monocytes from healthy subjects were infected with M. avium and cultured with or without antimicrobials for 8 days. Some quinolones had poor activity against M. avium in the monocyte culture system despite low MICs (< or = 0.25 mg/L); in contrast, some quinolones with MICs > 32 mg/L showed some inhibition of M. avium growth within monocytes at 4 mg/L. Six quinolones synthesized based on structure-activity analysis were more active than ciprofloxacin. These data underscore the importance of evaluating drug activity of new antimicrobial agents against intracellular pathogens in a macrophage model as well as in cell-free systems.

Anti-Infective Agents↗
PubMed1996

Selective induction of transforming growth factor beta in human monocytes by lipoarabinomannan of Mycobacterium tuberculosis.

The induction of macrophage-deactivating (interleukin-10 [IL-10] and transforming growth factor beta [TGF-beta] and macrophage-activating (IL-1, IL-6, and tumor necrosis factor alpha [TNF-alpha] cytokines by lipoarabinomannan (LAM) from pathogenic Mycobacterium tuberculosis Erdman and H37Rv strains (ManLAM) and nonpathogenic mycobacteria (AraLAM) in human blood monocytes was examined. ManLAM was significantly less potent in induction of TNF-alpha, IL-1, IL-6, and IL-10 protein and mRNA, whereas its ability to induce TGF-beta was similar to that of AraLAM. Differences in induction of TNF-alpha mRNA by the two LAM preparations only became apparent at late time points of culture (24 h). The induction of TNF-alpha and IL-1 by purified protein derivative of M. tuberculosis was significantly stronger than that by ManLAM. Pretreatment of monocytes with ManLAM did not, however, interfere with cytokine induction by lipopolysaccharide or AraLAM. The extensive mannosyl capping of arabinose termini of ManLAM may underlie the lack of ability to induce some cytokines (IL-1, TNF-alpha, and IL-10) and the retained ability to induce TGF-beta. The latter may have a role in shifting the cytokine milieu in favor of survival of M. tuberculosis.

Animals↗