PubMed Health⌕ Search

Biomedical subjects

T Calandra

Publications and source records attributed to T Calandra.

At least 55 records · Page 3Linked to original sources
PubMed1996

An essential role for macrophage migration inhibitory factor in the tuberculin delayed-type hypersensitivity reaction.

30 years ago, investigations into the molecular basis of the delayed-type hypersensitivity reaction (DTH) provided evidence for the first lymphokine activity: a lymphocyte-derived mediator called macrophage migration inhibitory factor (MIF), which inhibited the random migration of peritoneal macrophages. Despite the long-standing association of MIF with the DTH reaction and the cloning of a human protein with macrophage migration inhibitory activity, the precise role of MIF in this classic cell-mediated immune response has remained undefined. This situation has been further complicated by the fact that two other cytokines, interferon gamma and IL-4, similarly inhibit macrophage migration and by the identification of mitogenic contaminants in some preparations of cloned human MIF. Using recently developed molecular probes for mouse MIF, we have examined the role of this protein in a classical model of DTH, the tuberculin reaction in mice. Both MIF messenger RNA and protein were expressed prominently in DTH lesions, as assessed by reverse transcription polymerase chain reaction, in situ hybridization, and immunostaining with anti-MIF antibody. The predominant cellular origin of MIF appeared to be the monocyte/macrophage, a cell type identified recently to be a major source of MIF release in vivo. The administration of neutralizing anti-MIF antibodies to mice inhibited significantly the development of DTH, thus affirming the central role of MIF in this classic immunological response.

Animals↗
PubMed1996

Monotherapy with meropenem versus combination therapy with ceftazidime plus amikacin as empiric therapy for fever in granulocytopenic patients with cancer. The International Antimicrobial Therapy Cooperative Group of the European Organization for Research and Treatment of Cancer and the Gruppo Italiano Malattie Ematologiche Maligne dell'Adulto Infection Program.

Combinations of beta-lactams plus aminoglycosides have been standard therapy for suspected infections in granulocytopenic cancer patients, especially those with profound long-lasting granulocytopenia. With the advent of new broad-spectrum bactericidal antibiotics such as extended-spectrum cephalosporins or carbapenems, the need to combine beta-lactams with aminoglycosides became more controversial. The objective of this prospective randomized multicenter study was to compare the efficacy, safety, and tolerance of meropenem monotherapy with those of the combination of ceftazidime plus amikacin for the empirical treatment of fever in granulocytopenic cancer patients. Of 1,034 randomized patients, 958 were assessable in the intent-to-treat analysis for response to antibacterial therapy, including 483 in the meropenem group and 475 in the ceftazidime-plus-amikacin group. The median durations of neutropenia were 16 and 17 days, respectively. A successful outcome was reported in 270 of 483 (56%) patients treated with monotherapy compared with 245 of 475 (52%) patients treated with the combination group (P = 0.20). The success rates in the monotherapy group and the combination group were similar by type of infection (single gram-negative bacteremia, single gram-positive bacteremia, clinically documented infection, and possible infection). The occurrence of further infections assessed in patients for whom the allocated regimen was not modified did not differ between the two groups (12% in both groups). Mortality due to the presenting infection or further infection was relatively low (8 patients treated with the monotherapy compared with 13 patients treated with the combination). A total of 1,027 patients were evaluable for adverse events; the proportion of those who developed adverse effects was similar between the two groups (29% in both groups), and only 19 (4%) patients in the monotherapy group and 31 (6%) in the combination group experienced an adverse event related or probably related to the study drug. Allergic reactions were the only reason for stopping the protocol antibiotic(s) (3 and 5 patients, respectively). This study confirms that monotherapy with meropenem is as effective as the combination of ceftazidime plus amikacin for the empiric treatment of fever in persistently granulocytopenic cancer patients, and both regimens were well tolerated.

Adolescent↗
PubMed1995

MIF as a glucocorticoid-induced modulator of cytokine production.

Glucocorticoid hormones are important for vital functions and act to modulate inflammatory and immune responses. Yet, in contrast to other hormonal systems, no endogenous mediators have been identified that can directly counter-regulate their potent anti-inflammatory and immunosuppressive properties. Recent investigations of the protein macrophage migration inhibitory factor (MIF), which was discovered originally to be a T-lymphocyte-derived factor, have established it to be a pro-inflammatory pituitary and macrophage cytokine and a critical mediator of septic shock. Here we report the unexpected finding that low concentrations of glucocorticoids induce rather than inhibit MIF production from macrophages. MIF then acts to override glucocorticoid-mediated inhibition of cytokine secretion by lipopolysaccharide (LPS)-stimulated monocytes and to overcome glucocorticoid protection against lethal endotoxaemia. These observations identify a unique counter-regulatory system that functions to control inflammatory and immune responses.

Animals↗
PubMed1995

Increased circulating soluble CD14 is associated with high mortality in gram-negative septic shock.

The soluble glycoprotein sCD14 binds lipopolysaccharide, a complex that activates endothelial cells and that may be crucial in gram-negative sepsis. Therefore, serum sCD14 was analyzed in 54 patients with gram-negative septic shock and in 26 healthy controls. sCD14 was tested by ELISA and Western blotting. Patients had higher sCD14 concentrations than controls (median, 3.23 vs. 2.48 micrograms/mL, P = .002). Increased levels were associated with high mortality (median, 4.2 micrograms/mL in nonsurvivors vs. 2.8 micrograms/mL in survivors, P = .001). sCD14 was found in two isoforms (49 and 55 kDa) in monocyte cultures. In sera only one of either form was detectable. Controls had the 49-kDa form, and patients had either the 49- or 55-kDa form, but patients with high levels of sCD14 had only the 55-kDa form. Twenty-one (53%) of 39 with the 55-kDa form and 8 (57%) of 14 with the 49-kDa form died. Thus, the level of sCD14 but not its biochemical form had a prognostic value in patients with gram-negative septic shock.

Adolescent↗
PubMed1995

Piperacillin-tazobactam plus amikacin versus ceftazidime plus amikacin as empiric therapy for fever in granulocytopenic patients with cancer. The International Antimicrobial Therapy Cooperative Group of the European Organization for Research and Treatment of Cancer.

Gram-positive bacteria have become the predominant infecting organisms in granulocytopenic cancer patients. Empiric antibiotic regimens used in febrile neutropenic patients often include an extended-spectrum cephalosporin, but the response to therapy in gram-positive coccal bacteremia has been unsatisfactory. Thus, new antibiotics with better activity against gram-positive bacteria should be tested. The objective of this prospective randomized controlled study was to evaluate and compare the efficacy and tolerance of piperacillintazobactam plus amikacin with that of ceftazidime plus amikacin, the standard regimen of the International Antimicrobial Therapy Cooperative Group of the European Organization for Research and Treatment of Cancer, in the empiric treatment of febrile granulocytopenic cancer patients. A total of 858 episodes were eligible for this study, and 706 episodes were assessable for efficacy. The antibiotic treatment was successful in 210 (61%) of 342 episodes in the piperacillin-tazobactam-amikacin group compared with 196 (54%) of 364 episodes treated with ceftazidime plus amikacin (P = 0.05). The time to defervescence was significantly shorter (P = 0.01) and the time to failure was significantly longer (P = 0.02) in the piperacillin-tazobactam-amikacin group. A significant difference in response to bacteremic infections between the two patient groups was found: piperacillin-tazobactam plus amikacin was successful in 40 of 80 episodes (50%), and ceftazidime plus amikacin was successful in 35 of 101 episodes (35%) (P = 0.05). A multivariate analysis showed that the probability of failure was significantly greater with ceftazidime plus amikacin than with piperacillin-tazobactam plus amikacin (P = 0.02). This trial suggests that piperacillin-tazobactam plus amikacin is more effective than ceftazidime plus amikacin for the empiric treatment of fever and bacteremia in granulocytopenic cancer patients. Although cutaneous reaction was more frequently associated with piperacillin-tazobactam plus amikacin than with ceftazidime-amikacin, this unwanted effect was relatively mild and its incidence was comparable to that of other penicillin compounds.

Adolescent↗
PubMed1995

Localization of macrophage migration inhibitory factor (MIF) to secretory granules within the corticotrophic and thyrotrophic cells of the pituitary gland.

BACKGROUND: Macrophage migration inhibitory factor (MIF) was one of the first lymphokine activities to be discovered and was described almost 30 years ago to be a soluble factor(s) produced by activated T lymphocytes. In more recent studies, MIF has been "rediscovered" to be an abundant, pre-formed constituent of the anterior pituitary gland and the macrophage, and to be a critical component in the host response to septic shock. Pituitary-derived MIF enters the circulation after infectious or stressful stimuli and appears to act to counterregulate glucocorticoid suppression of cytokine production. MATERIALS AND METHODS: Immunoelectron microscopy utilizing a combination of anti-MIF and anti-pituitary hormone-specific antibodies was used to study the ultrastructural localization of MIF within the anterior pituitary gland. Pituitaries were obtained from resting, unstimulated mice and from mice 16 hr after endotoxin administration. The release of MIF also was investigated in vitro by examining the effect of corticotropin-releasing hormone (CRH_ on the AtT-20, corticotrophic cell line. RESULTS: MIF localizes to granules present exclusively in ACTH and TSH secreting cells. Within each cell type, a subset of granules was found to contain both MIF and ACTH, or MIF and TSH. The pituitary content of MIF-containing granules decreased significantly after experimentally induced endotoxemia. In seven pituitaries examined 16 hr after LPS injection, the number of MIF-positive granules diminished by 38% in corticotrophic cells and by 48% in thyrotrophic cells when compared with controls (p < 0.05). CRH was observed to be a potent MIF secretagogue in vitro, inducing the release of MIF from corticotrophic cells at concentrations lower than that required for ACTH release. CONCLUSION: These data provide ultrastructural information that identify MIF to be a novel anterior pituitary hormone, support earlier studies showing a time-dependent release of pituitary MIF during endotoxemia, and suggest an important, systemic role for MIF in the stress response to infection and other stimuli.

Adrenocorticotropic Hormone↗
PubMed1994

Purification, bioactivity, and secondary structure analysis of mouse and human macrophage migration inhibitory factor (MIF).

The cytokine macrophage migration inhibitory factor (MIF) has been identified to be secreted by the pituitary gland and the monocyte/macrophage and to play an important role in endotoxic shock. Despite the recent molecular cloning of a human T-cell MIF, characterization of the biochemical and biological properties of this protein has remained incomplete because substantial quantities of purified, recombinant, or native MIF have not been available. We describe the cloning of mouse MIF from anterior pituitary cells (AtT-20) and the purification of native MIF from mouse liver by sequential ion exchange and reverse-phase chromatography. For comparison purposes, human MIF was cloned from the Jurkat T-cell line and also characterized. Mouse and human MIF were highly homologous (90% identity over 115 amino acids). Recombinant mouse and human MIF were expressed in Escherichia coli and purified in milligram quantities by a simple two-step procedure. The molecular weight of native mouse MIF (12.5 kDa monomer) was identical with that of recombinant mouse MIF as assessed by gel electrophoresis and mass spectroscopy. No significant post-translational modifications were detected despite the presence of two potential N-linked glycosylation sites. Recombinant MIF inhibited monocyte migration in a dose-dependent fashion, and both recombinant and native MIF-exhibited comparable biological activities. MIF induced the secretion of tumor necrosis factor-alpha and stimulated nitric oxide production by macrophages primed with interferon-gamma. Circular dichroism spectroscopy revealed that bioactive mouse and human MIF exhibit a highly ordered, three-dimensional structure with a significant percentage of beta-sheet and alpha-helix conformation. Guanidine hydrochloride-induced unfolding experiments demonstrated that MIF is of low to moderate thermodynamic stability. These studies establish the biochemical identity of native and recombinant MIF and provide a first insight into the three-dimensional structural properties of this critical inflammatory mediator.

Amino Acid Sequence↗
PubMed1994

The macrophage is an important and previously unrecognized source of macrophage migration inhibitory factor.

For over 25 years, the cytokine known as macrophage migration inhibitory factor (MIF) has been considered to be a product of activated T lymphocytes. We recently identified the murine homolog of human MIF as a protein secreted by the pituitary in response to endotoxin administration. In the course of these studies, we also detected MIF in acute sera obtained from endotoxin-treated, T cell-deficient (nude), and hypophysectomized mice, suggesting that still more cell types produce MIF. Here, we report that cells of the monocyte/macrophage lineage are an important source of MIF in vitro and in vivo. We observed high levels of both preformed MIF protein and MIF mRNA in resting, nonstimulated cells. In the murine macrophage cell line RAW 264.7, MIF secretion was induced by as little as 10 pg/ml of lipopolysaccharide (LPS), peaked at 1 ng/ml, and was undetectable at LPS concentrations > 1 microgram/ml. A similar stimulation profile was observed in LPS-treated peritoneal macrophages; however, higher LPS concentrations were necessary to induce peak MIF production unless cells had been preincubated with interferon gamma (IFN-gamma). In RAW 264.7 macrophages, MIF secretion also was induced by tumor necrosis factor alpha (TNF-alpha) and IFN-gamma, but not by interleukins 1 beta or 6. Of note, MIF-stimulated macrophages were observed to secrete bioactive TNF-alpha. Although previously overlooked, the macrophage is both an important source and an important target of MIF in vivo. The activation of both central (pituitary) and peripheral (macrophage) sources of MIF production by inflammatory stimuli provides further evidence for the critical role of this cytokine in the systemic response to tissue invasion.

Animals↗
PubMed1994

The emerging role of MIF in septic shock and infection.

The protein mediator described originally as macrophage migration inhibitory factor (MIF) has been "re-discovered" recently to be both a novel pituitary hormone and a pro-inflammatory, macrophage-derived cytokine. Emerging studies indicate that MIF plays a pivotal role not only in endotoxic shock but also in the host response to a variety of acute and chronic infections.

Animals↗
PubMed1994

Bacteremia due to viridans streptococci in neutropenic patients: a review.

Viridans streptococci have long been considered, with the exception of the ability to cause endocarditis, as minor pathogenic agents. More recently, however, these bacteria have become a major concern in neutropenic patients undergoing a chemotherapeutic treatment. In this high-risk population, they can be responsible for up to 39% of bacteremia cases and are the most frequent cause of this type of infection. The most frequently isolated species in blood cultures are Streptococcus mitis and Streptococcus sanguis II. Viridans streptococcus bacteremia can be accompanied by serious complications, like adult respiratory distress syndrome (ARDS) (3% to 33%), shock (7% to 18%) or endocarditis (7% to 8%). Mortality rates range from 6% to 30%. Case-control studies have identified the following risk factors: severe neutropenia (< 100 neutrophils/mm3), prophylactic antibiotic treatments with quinolone or co-trimoxazole, absence of intravenous antibiotics at the time of bacteremia, high doses of cytosine arabinoside, oropharyngeal mucositis, and heavy colonization by viridans streptococci. The introduction of penicillin in prophylactic antibiotic treatments has reduced the incidence of these infections, but the long-term use of penicillin could be compromised by the emergence of resistant strains.

Bacteremia↗
PubMed1994

Factors associated with bacteraemia in febrile, granulocytopenic cancer patients. The International Antimicrobial Therapy Cooperative Group (IATCG) of the European Organization for Research and Treatment of Cancer (EORTC).

The objective of this investigation was to determine factors predictive of bacteraemia at presentation in febrile, granulocytopenic cancer patients in order to estimate the probability of bacteraemia in each patient, and to compare factors associated with a diagnosis of gram-positive or gram-negative bacteraemia. Retrospective analysis of two sets of data (derivation and validation sets) randomly obtained from a large prospective study was conducted in a multicentre study of febrile, granulocytopenic cancer patients admitted for empiric antibacterial therapy. Within the derivation set, prognostic factors (clinical and laboratory data) likely to be associated with a generic diagnosis of bacteraemia and with a specific diagnosis of gram-positive or gram-negative bacteraemia were analysed by means of three backward, stepwise, logistic regression analyses. The predictive probability of bacteraemia was calculated using the logistic equation. The discriminating ability of the model in predicting bacteraemia was evaluated in the derivation and validation sets using receiver-operating characteristic curves. The predictive probability of gram-positive or gram-negative bacteraemia was not calculated. In the derivation set, 157 of 558 episodes (28%) were microbiologically documented bacteraemias. Predicting factors were antifungal prophylaxis, duration of granulocytopenia before fever, platelet count, highest fever, shock and presence and location of initial signs of infection. The variables institution, antibacterial prophylaxis and underlying disease showed borderline associations with bacteraemia. Shock was associated with gram-negative bacteraemia, while signs of infection at catheter site were predictive of gram-positive bacteraemia. Quinolone prophylaxis was negatively associated with gram-negative bacteraemia. When tested in the validation set, the model was poorly predictive, although a small subgroup of episodes (representing only 16% of the total sample size) with low risk of bacteraemia was identified. Factors predictive of bacteraemia can be identified, with discrimination between gram-positive and gram-negative aetiology. Further studies are warranted in order to improve the discriminant ability of the model.

Adolescent↗
PubMed1994

Macrophage migration inhibitory factor is a neuroendocrine mediator of endotoxaemia.

The cytokine macrophage migration inhibitory factor (MIF) is a major protein constituent of the anterior pituitary gland released into the bloodstream during endotoxaemia. For many years, MIF had been thought to be a T cell product associated with delayed-type hypersensitivity reactions. The identification of MIF as a pituitary 'stress' hormone provides an important link in the regulation of systemic inflammatory responses by the central nervous system.

Animals↗
PubMed1994

Bacteremia due to viridans streptococcus in neutropenic patients with cancer: clinical spectrum and risk factors.

Between 1988 and 1991, 26 episodes of bacteremia due to viridans streptococci occurred in 25 neutropenic patients undergoing intensive chemotherapy for hematologic malignancies. Complications related to the bacteremia were observed in 10 episodes: unilateral pulmonary infiltrates (4), acute respiratory distress syndrome (ARDS) (4), hypotension (3), and endocarditis (2). All patients with ARDS had received high doses of cytosine arabinoside and had bacteremia due to Streptococcus mitis. Death occurred in three patients (12%) but was possibly related to bacteremia in only one case. Case patients who had received prophylaxis with quinolones were compared with matched control patients who received similar prophylaxis but who did not have bacteremia due to viridans streptococci. Multivariate analysis of predisposing factors showed that high doses of cytosine arabinoside (P = .01), the presence of mucositis (P = .02), and the absence of previous therapy with parenteral antibiotics (P = .01) were independent risk factors for the development of viridans streptococcal bacteremia. Of 259 patients who had received quinolone prophylaxis during the study period, 22 (8.5%) developed an episode of viridans streptococcal bacteremia as compared with three episodes (3.7%) in 82 patients who had received a quinolone and penicillin (P = .07). However, the latter three episodes were caused by strains with decreased susceptibility to penicillin, thus suggesting that resistance to penicillin might limit the use of this antibiotic as a prophylactic agent in the future.

4-Quinolones↗
PubMed1994

Lipopolysaccharide (LPS)-binding protein in human serum determines the tumor necrosis factor response of monocytes to LPS.

Lipopolysaccharide (LPS)-binding protein (LBP) and CD14 represent key elements in monocyte activation by LPS. The mean concentration of LBP was 18.1 microgram/mL in normal serum and 40-60 micrograms/mL in serum of patients with septic shock, independent of the fact that patients had gram-negative or other infections. Ten percent normal serum presented large concentrations of LPS (in the microgram range) to monocytes. Only when diluted 1:100 was LBP in plasma a limiting factor for monocyte activation, as measured by tumor necrosis factor (TNF) release. When LBP was depleted from serum with anti-LBP antibodies, the resulting serum did not support TNF release of monocytes upon LPS challenge. In conclusion, monocyte activation resulting in TNF secretion was related to LBP, which is abundantly present in normal serum, and elevated two to three times in patients with septic shock.

Acute-Phase Proteins↗
PubMed1993

MIF is a pituitary-derived cytokine that potentiates lethal endotoxaemia.

Cytokines are critical in the often fatal cascade of events that cause septic shock. One regulatory system that is likely to be important in controlling inflammatory responses is the neuroendocrine axis. The pituitary, for example, is ideally situated to integrate central and peripheral stimuli, and initiates the increase in systemic glucocorticoids that accompanies host stress responses. To assess further the contribution of the pituitary to systemic inflammatory processes, we examined the secretory profile of cultured pituitary cells and whole pituitaries in vivo after stimulation with bacterial lipopolysaccharide (LPS). Here we identify macrophage migration inhibitory factor (MIF) as a major secreted protein release by anterior pituitary cells in response to LPS stimulation. Serum analysis of control, hypophysectomized and T-cell-deficient (nude) mice suggests that pituitary-derived MIF contributes to circulating MIF present in the post-acute phase of endotoxaemia. Recombinant murine MIF greatly enhances lethality when co-injected with LPS and anti-MIF antibody confers full protection against lethal endotoxaemia. We conclude that MIF plays a central role in the toxic response to endotoxaemia and possibly septic shock.

Acute-Phase Reaction↗
PubMed1993

Cefepime monotherapy for the empirical treatment of fever in granulocytopenic cancer patients.

In a pilot study, we evaluated the efficacy and the safety of cefepime, a new cephalosporin with extended-spectrum activity against both Gram-positive and Gram-negative bacteria, as empirical monotherapy for 108 febrile episodes in 84 granulocytopenic cancer patients. Cefepime (2 g tds) was given for a minimum of 7 days or until resolution of infection. Of the 108 episodes, 91 were evaluable. Microbiologically documented infections occurred in 25 patients (27%) (18 Gram-positive, 7 Gram-negative), of whom 18 had bacteraemia. Infection was clinically documented in 47 patients (52%) and fever was unexplained in 19 (21%). Overall, 71% (65/91) of the infections resolved. Response rates were 86% (6/7) for Gram-negative infections, 44% (8/18) for Gram-positive infections (57% for cefepime-susceptible Gram-positive bacteria), 77% (36/47) for clinically documented infections and 79% (15/19) for unexplained fevers. Of the 26 patients (29%) whose primary infections did not improve with cefepime monotherapy, 23 responded after the addition of other antibiotics. Sixteen patients (18%) developed secondary infections of which 13 were microbiologically documented; Gram-positive bacteria were isolated from seven patients, Gram-negative bacteria from two, fungi from three and a virus from one. Adverse effects were mild and did not require premature discontinuation of therapy except for one patient who developed an immediate allergic reaction after the first dose of cefepime from which he recovered fully. The survival rate after resolution of granulocytopenia was 96%; three patients died of primary bacterial infection and one from secondary disseminated candidiasis. In this pilot study, cefepime monotherapy appeared safe and effective as empirical therapy for fever in cancer patients with granulocytopenia. Whether cefepime is superior to other advanced-generation cephalosporins for the treatment of Gram-positive infections will require evaluation in a larger comparative study.

Adolescent↗