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PubMed1981

Abnormalities of blood coagulation in patients with cancer. Mononuclear cell tissue factor generation.

Activation of blood coagulation, as characterized by the occurrence of disseminated intravascular coagulation, increased levels of plasma FPA, and the local deposition of fibrin, is common in both experimental animals and patients with malignant tumors. Many mechanisms have been proposed for the mediation of this response to tumors, including tumor-associated proteases, platelet adherence to tumors, surface activation of blood coagulation by tumor cells, and activation of coagulation by tissue factor derived from either tumor tissue or reactive leukocytes. We have investigated the hypothesis that MTF generation may contribute to increased fibrin generation in cancer patients. Plasma FPA levels and in vitro unstimulated MTF generation were measured simultaneously in samples obtained from 35 patients with lung cancer. FPA levels were significantly elevated in these patients as compared to a group of 20 normal volunteers (p = 0.03). Although unstimulated MTF generation showed considerable variability in both the patients and the normal volunteers, a high degree of correlation was observed between simultaneous levels of FPA and MTF regardless of whether MTF was expressed per cell (r = 0.83), per monocyte (r = 0.95), or per volume of peripheral blood (r = 0.96). MTF generation was also significantly decreased in a group of patients receiving sodium warfarin (p less than 0.001). These results suggest a potential role for MTF generation in the activation of blood coagulation in neoplasia and also suggest the possibility that inhibition of MTF generation by warfarin may be partially responsible for the decreased FPA values previously reported in anticoagulated cancer patients.

Aged↗
PubMed1995

Differential effects of granulocyte-macrophage colony-stimulating factor on eosinophil and neutrophil superoxide anion generation.

Eosinophils (EOS) are specifically recruited to sites of allergic inflammation and parasitic infection, while neutrophil (NEUT) influx predominates in bacterial infections. This biologic selectivity suggests that granulocytes may respond differently to inflammatory mediators such as granulocyte-macrophage-CSF (GM-CSF). To establish the mechanisms of the response of granulocytes to GM-CSF, isolated human peripheral blood EOS and NEUT were obtained from allergic rhinitis patients and incubated in vitro with this cytokine. Incubation with GM-CSF (10 or 100 pM) significantly enhanced FMLP-stimulated EOS superoxide anion (O2-) generation, LTC4 release, and adhesion to tissue culture plates. Both GM-CSF-enhanced EOS adhesion and O2- generation were inhibited by an anti-beta 2 (CD18) Ab suggesting that this beta 2 integrin was associated with increased cell function. In contrast, FMLP + cytochalasin B were required to demonstrate GM-CSF enhancement of NEUT O2- and LTB4 generation; GM-CSF had no effect on NEUT adhesion. Furthermore, GM-CSF augmentation of FMLP + cytochalasin B-activated NEUT O2- generation was not affected by anti-beta 2 Ab but was blocked by a 5-lipoxygenase-activating protein antagonist, BAY x 1005. Finally, 0.1 to 10 nM LTB4 mimicked the GM-CSF-priming effect on NEUT O2- generation, thus suggesting that the augmented NEUT respiratory burst was the result of LTB4 production and its effect on the NEUT. These data demonstrate that GM-CSF promotes EOS and NEUT O2- generation to FMLP via distinct mechanisms: enhanced adhesion of EOS vs autocrine-priming by enhanced LTB4 generation of NEUT.

Adult↗
PubMed1994

Biodemographic and sociocultural factors in two generations of families from six Polish rural and urban populations.

There were investigated 6967 families from 6 rural regions, under industrialization, and industrialized urban regions. In the grandparents generation there were taken into account 10 traits (an education level, a mating radius, and a stature) and in parents generation 17 traits (the mentioned-above ones and a number of family members, a flat size, incomes, an employees No., a life mode, smoking etc. Numerical characteristics of traits have been calculated jointly and separately in six populations, matrices of correlation have been constructed and moreover factorial analysis have been carried out, as a result of which 8 rotated factors have been obtained. The highest cultural mobility (increase in the level of education) from generation to generation occurs in the population of textile industry town Lódź. The highest improvement of biological status, the increase in mating radius and high incomes are characteristic for this regions, too. On the other side are villages with low culture mobility (not large increase in education level), slight improvement of biological status, almost no migrations, overcrowded flats and low income per family member. The relations between pairs of traits appear to vary largely in several populations. Generally is a high correlation between the education level of the same family members in both generations. The has been stated negative correlation between grandfather stature both of the mother and the father lines, with occurring of positive assortative mating in the couples of two generations. In both investigated generations there is the positive assortative mating, but the negative correlation in the stature between grandfathers of the mother and the father lines. The grandparents education level is correlated with their and their offsprings stature. The duration of holidays is one of the best (closely correlated with others) indicators of life mode, and partially of a given family living conditions, too. 8 hidden factors have been separated: a consciousness, mode of life, a number of family members, a genetic factor (stature), migrations, living conditions, incomes. This 8 factors have different ranks (evaluated as a position in sequence expressing in % the share in being explained variance) in six investigated rural and urban populations, explaining together 54-55% of the total variance of analyzed family traits. The consciousness occurs generally as a first factor. As far, as the mode of life is concerned, the rank of its factor is less in villages than in towns, and reciprocally the ranks of such factors as a number of family members, migrations and living conditions, are greater in villages than in towns.

Adult↗
PubMed1995

[Effect of intracerebroventricular injection of IL-1 beta on generation of immuno-suppressive factor in lymphocytes in stressed mice].

Our previous work showed that a suppressive factor (a protein with large molecular weight) in serum was induced by restraint stress in mice and rats, which suppressed Con A induced lymphocyte proliferation. It was also found that the generation of serum suppressive factor was under control of the central nervous system. Our further study showed that intracerebroventricular (icv) injection of interleukin 1 receptor antagonist (IL-1Ra) antagonised the generation of serum suppressive factor induced by restraint stress and icv injection of interleukin-1 beta (IL-1 beta) increased the generation of the suppressive factor. Our experiment also showed that the serum suppressive factor induced by restraint stress was first made in lymph tissue and then released into blood. The present work was designed to investigate the role of IL-1 in the brain in generation of the suppressive factor in lymph node in mice. Icv injection of IL-1 beta (1 pg/mouse) was shown to significantly increase the generation of the suppressive factor in lymph node. Icv injection of IL-1Ra, however, antagonised generation of the suppressive factor. In mice without restraint stress, both the suppressive factor in serum and in lymph node were found to be induced in dose-dependent manner by icv injection of IL-1 beta. Taken together, these results suggest that IL-1 beta in brain played a very important role in generation of the suppressive factor in lymph node. The positive correlation between the suppressive action of lymph node and of serum added to the evidence that lymph tissue is probably the source of the serum suppressive factor.

Animals↗
PubMed1995

Singlet oxygen generation in the superoxide reaction.

ESR spin trapping was utilized to study the singlet oxygen (1O2) generation in the reaction of superoxide (O2) with H2O2. The spin trap used was 2,2,6,6-tetramethyl-4-piperdone. Incubation of xanthine, xanthine oxidase and H2O2 generated 1O2 spin adduct signal. Omission of xanthine, xanthine oxidase or H2O2 caused a sharp decrease in 1O2 generation. 1O2 scavenger, sodium azide, inhibited 1O2 generation while .OH scavenger, ethanol, only slightly decreased the signal intensity. Potassium superoxide (KO2) decomposition generated 1O2. Catalase and sodium azide inhibited 1O2 generation and H2O2 enhanced it. The results demonstrate that O2 is capable of generating 1O2 upon reaction with H2O2.

Azides↗
PubMed1994

[Interleukin-5-induced generation of superoxide by eosinophils in asthma].

Superoxide generation was assessed in highly purified eosinophils (> 99.0% pure) with a flow cytometer. Eosinophils from patients with asthma were collected by centrifugation of leukocytes on Percoll density gradients, followed by negative immunoselection with anti-CD16 monoclonal antibodies. For comparison, highly purified neutrophils (< 99.5% pure) were collected by a similar method with anti-CD9 monoclonal antibodies. After incubation with a fluorescent probe, the cells were stimulated with various concentrations of PAF, PMA or various cytokines. Both eosinophils and neutrophils generated superoxide dose-dependently in response to PAF and PMA. Eosinophils generated superoxide in response to IL-3 and IL-5 (maximum concentration was 50 ng/ml), but neutrophils did not. IL-5-induced superoxide generation was lower in the presence of IL-5 antibodies. After stimulation with PMA, superoxide generation was significantly higher in neutrophils than in eosinophils (p < 0.05). There were no significant differences in PAF-induced or GM-CSF-induced superoxide generation between eosinophils and neutrophils. After stimulation with the optimal concentration of IL-5 or PMA, eosinophils with a lower density generated significantly more superoxide than those with a higher density.

Asthma↗
PubMed1995

The five generations of American medical revolutions.

Current medical authors frequently use the term "revolution," yet American medicine is resisting change rather than embracing it. The last completed American medical revolutionary movement was the specialist-technologist movement of the late 19th and early 20th centuries. This paper describes a five-generational model of revolution. First-generation persons foment revolution; second-generation persons shape it into workable form and precipitate conflict; third-generation persons join the fight only when it appears to be all but won; fourth-generation persons enjoy the fruits of revolution; and fifth-generation persons, having risen to domination in the mature system, resist all attempts at reform by the next round of revolutionaries. In political revolutions, severe reactionary activity by the ruling party is often an indicator of an imminent overthrow by revolution. In scientific revolutions, the opposition of an established (specialist-technologist) paradigm to an emerging alternative (generalist) paradigm increases in intensity as the old order declines in strength; the opposition becomes most fierce just before the collapse of the old order. American specialist-technologist medicine, declining into its senescent fifth generation, will resist all but incremental change whenever possible, and accept major change only by force.

Family Practice↗
PubMed1993

CD2-deficient mice generate virus-specific cytotoxic T lymphocytes upon infection with lymphocytic choriomeningitis virus.

The major host response to many viral infections is the generation of virus-specific CTL. Many protein molecules on the surfaces of both CTL and target cells interact to mediate adhesion of the cells and generate signals that lead to T cell activation and proliferation of virus-specific CTL that then mediate lysis of infected cells. One such protein, CD2, has been shown to increase the binding affinity of CTL to infected cells, and, in addition, enhance CTL activation signals. To determine whether virus-specific CTL could be generated in the absence of CD2, mice lacking a functional CD2 gene were infected with lymphocytic choriomeningitis virus (LCMV), and the responses to the virus were monitored. CD2-deficient mice infected intracerebrally with LCMV died as a consequence of CTL-mediated choriomeningitis, similar to control littermates. Additionally, CD2-deficient mice inoculated i.p. with LCMV cleared the infection by 2 wk postinfection, as did control mice. Viral clearance in these mice was shown to be due to the generation of a vigorous virus-specific MHC-restricted CTL response. Finally, to determine whether CD2 is essential for the generation of memory CTL, we examined the ability of CD2-deficient mice to generate memory CTL to LCMV and found normal memory CTL responses. Our results indicate that CD2 is not required for the generation of an LCMV-specific CTL response in vivo, nor is CD2 required for the maintenance or activation of memory CTL.

Animals↗
PubMed1994

Determination of the mechanism of free radical generation in human aortic endothelial cells exposed to anoxia and reoxygenation.

Endothelial cell-derived oxygen free radicals are important mediators of postischemic injury; however, the mechanisms that trigger this radical generation are not known, and it is not known if this process can occur in human cells and tissues. The enzyme xanthine oxidase can be an important source of radical generation; however, it has been reported that this enzyme may not be present in human endothelium. To determine the presence and mechanisms of radical generation in human vascular endothelial cells subjected to anoxia and reoxygenation, electron paramagnetic resonance measurements were performed on cultured human aortic endothelial cells using the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO). These measurements were correlated with cellular injury, xanthine oxidase activity, and alterations in cellular nucleotides. Upon reoxygenation after 60 min of anoxia, large DMPO-OH (aN = aH = 14.9 G) and smaller DMPO-R (aN = 15.8 G, aH = 22.8 G) signals were seen. Superoxide dismutase totally quenched this radical generation. The ferric iron chelator deferoxamine prevented cell death and totally quenched the DMPO-R signal with a 40% decrease in the DMPO-OH signal. Xanthine oxidase was shown to be present in these cells and to be the primary source of free radicals. While the concentration of this enzyme did not change after anoxia, the concentration of its substrate, hypoxanthine, markedly increased, resulting in increased free radical generation upon reoxygenation. Thus, reoxygenated human vascular endothelial cells generate superoxide free radicals, which further react with iron to form the reactive hydroxyl radical, which in turn causes cell death. Xanthine oxidase was the primary source of radical generation with this process triggered by the breakdown of ATP to the substrate hypoxanthine during anoxia.

Aorta↗
PubMed1994

Multinucleated giant cells generation induced by interferon-gamma. Changes in the expression and distribution of the intercellular adhesion molecule-1 during macrophages fusion and multinucleated giant cell formation.

BACKGROUND: Multinucleated giant cells (MGC), interferon-gamma (IFN-gamma) production, and increased expression of adhesion molecules are features of granulomatous reactions. IFN-gamma induces the fusion of macrophages and the subsequent MGC generation in vitro. Moreover, IFN-gamma increases ICAM-1 expression on lymphoid cells and an important role for adhesion molecules in MGC generation has been proposed. EXPERIMENTAL DESIGN: The time course of the IFN-gamma-driven MGC generation was investigated in slide-chamber cultures of adherence-purified human monocytes. The fusion index, the monocytes clustering the total number of MGC were determined. The expression of intercellular cell adhesion molecule-1 (ICAM-1), LFA-1 and HLA-DR was investigated by immunohistochemistry. The effect of anti-ICAM-1, anti-LFA-1 and anti-HLA-DR monoclonal antibodies on IFN-gamma-induced MGC generation was also examined. RESULTS: IFN-gamma enhanced the generation of MGC in a dose- and time-dependent fashion. In all experiments, MGC formation was preceded by a sequence of changes in the morphology of cultured monocytes. Cell clustering occurred as early as 3 days after IFN-gamma stimulation and was followed by the adhesion of cells that eventually fused. Immunohistochemistry showed that ICAM-1 was increased by IFN-gamma and constantly polarized on a cell uropode. When monocytes clustered, ICAM-1 was localized on the membrane where the cell-to-cell contact occurred. In newly formed MGC, ICAM-1 stained in the center of the giant cell. The cellular distribution of LFA-1 on cultured monocytes was not modified by IFN-gamma. HLA-DR expectedly enhanced by IFN-gamma was mostly cytoplasmic and tended to disappear when MGC formed. Finally, anti-LFA-1 and anti-ICAM-1 monoclonal antibodies variably inhibited IFN-gamma-induced MGC generation. CONCLUSIONS: Taken together, these data add support to the concept that IFN-gamma is essential for MGC generation by promoting cell clustering and cell-to-cell adhesion. The present data also indicate that among the mechanisms by which IFN-gamma exert such a promoting effect, changes in the ICAM-1 expression and cellular distribution are included. The observation that ICAM-1 appears to be trapped in the cytoplasm of IFN-gamma-driven MGC and that HLA-DR tend to disappear from macrophages undergoing MGC formation, also suggest changes in the functional properties of these cells.

Cell Fusion↗
PubMed1993

Long-term time-lapse cinemicrography of human erythroblasts under compression and without compression--direct measurement of generation time of each maturation stage.

The in vitro proliferation and the successive morphological alterations of single human erythroblasts were recorded for 5 days by time-lapse, phase-contrast cinemicrography. To visualize their fine structures more clearly, we introduced a new device to compress the erythroblasts under a cover slide. Appropriate compression did not significantly affect the capacity of the erythroblasts to proliferate and differentiate, although compression produced a slight tendency towards shorter generation time. The directly measured generation time was 24.5 +/- 4.5 h (mean +/- S.D.) for generation -1 (one generation prior to the orthochromatic erythroblast stage); 18.4 +/- 3.0 h for generation -2; and 18.3 +/- 4.1 h for generation -3 [corrected], these being arranged in inverse order of cell lineage. The cell size became progressively smaller and the nucleus-to-cytoplasm ratio decreased along with the maturation of the erythroblasts, showing a distinctive distribution range for each generation. Progression of hemoglobinization was simultaneously recorded qualitatively by Soret band absorption micrography. Cell movements characteristic for each maturation stage, e.g. perimitotic bleb-throwing of immature erythroblasts and vigorous movements of orthochromatic erythroblasts, heralding enucleation, were also clearly recorded. The method described here will be useful for the direct study of the dynamic morphology of the erythron in normal and abnormal states.

Cell Differentiation↗
PubMed1993

Modulation of superoxide anion generation by manoalide, arachidonic acid and staurosporine in liver infiltrated neutrophils in a rat model of endotoxemia.

Early accumulation of polymorphonuclear leukocytes (PMN) in the liver after in vivo exposure to Escherichia coli lipopolysaccharide (LPS) and concomitant in vitro phorbol myristate acetate (PMA)-stimulated superoxide anion (O2-) generation has recently been described in a rat model of endotoxemia. The purpose of this investigation was to study the role of phospholipase A2 (PLA2), arachidonic acid (AA), its metabolites, and protein kinase C (PKC) in the mechanism of PMA-stimulated O2- generation of liver infiltrated PMN as compared to circulating blood PMN. Rat PMN were isolated after a 1.5-h infusion of saline or LPS from the blood (SAL-PMN) or the liver (LPS-PMN), respectively. The following results were observed in both SAL-PMN and LPS-PMN: 1) Inhibitors of cyclooxygenase (indomethacin) and 5-lipoxygenase [eicosatetraynoic acid, WY 50,295 tromethamine and VZ 65, 4-(11-hydroxy-1,9-undecadiin)-brenzcatechin] pathways did not inhibit O2- generation; 2) the potent marine PLA2 inhibitor Manoalide inhibited O2- generation in a dose-dependent manner (IC50 = 0.5 microM); 3) exogenously added AA enhanced PMA-stimulated O2- generation in a time- and dose-dependent manner and partially reversed the effect of Manoalide in LPS-PMN; 4) staurosporine, a putative PKC inhibitor, blocked PMA-stimulated O2- generation completely in the absence of AA and 79% in the presence of AA. It was concluded that LPS-induced liver sequestration of PMN does not alter the role PLA2, AA and PKC play in PMA-stimulated O2- generation. These findings should have implications on the design of novel therapeutic approaches for the modulation of O2- release in the pathogenesis of LPS hepatotoxicity.

Alkaloids↗
PubMed1996

Insight into the mechanism(s) through which TNF promotes the generation of T cell-mediated antitumor cytotoxicity by tumor bearer splenic cells.

We have shown previously that addition of TNF to stimulation cultures of MOPC-315 tumor bearer splenic cell suspensions containing metastatic tumor cells capable of secreting TGF-beta greatly enhances the generation of anti-MOPC-315 lytic activity by their CD8+ T cells. The current studies were undertaken to gain some insight into the mechanism(s) through which TNF potentiates the in vitro generation of anti-MOPC-315 cytotoxicity by such tumor bearer splenic cells. Here we show that TNF is capable of 1) preventing completely the inhibitory activity of TGF-beta for CTL generation when both cytokines are added at the time of initiation of a 5-day stimulation culture and 2) reversing at least part of the inhibitory activity of TGF-beta when TNF is added as late as 3 days after TGF-beta addition. The costimulatory molecule B7-2 is shown here to be important for the realization of the potentiating activity of TNF for CTL generation by tumor bearer splenic cells. However, despite the importance of the B7-2 molecule, TNF does not mediate its immunopotentiating activity for CTL generation through up-regulation in IL-2 production. In addition, we show here that GM-CSF, but not IL-12, is important for the potentiating effect of TNF for CTL generation by tumor bearer splenic cells. Taken together, these studies identify several factors that are important for the realization of the potentiating effect of TNF for the in vitro generation of antitumor cytotoxicity by tumor-infiltrated splenic cells. It is not known at present, however, whether these factors utilize distinct and/or overlapping mechanisms in realizing the TNF effect.

Animals↗
PubMed1996

Comparative analysis of the cardiotoxicity proclivities of second generation antihistamines in an experimental model predictive of adverse clinical ECG effects.

Terfenadine and astemizole belong to the second generation histamine H1 antagonists and are widely prescribed for allergic and upper respiratory diseases. The popularity of the newer H1 antihistamines is due to their ability to provide relief from allergic symptoms without the undesirable side effect of sedation commonly associated with first generation H1 receptor antagonists such as diphenhydramine and promethazine. Recent clinical evidence that the second generation histamine H1 antagonists terfenadine and astemizole have the potential for inducing life threatening ventricular arrhythmias has raised questions as to whether other drugs in this class have similar cardiotoxic potential. The objective of this study was to evaluate and compare the arrhythmogenic potential of a series of second generation antihistamines in a quantitative experimental model predictive of adverse ECG effects in man. Antihistamines were given intravenously and electrocardiographic (ECG) and cardiovascular parameters (blood pressure and heart rate) were measured. The ECG wave form was analyzed to determine QTc interval, PR interval, QRS interval and heart rate. To determine the relative cardiotoxic potential of the antihistamines, the lowest dose producing significant prolongation of the QTc interval was compared with the dose required to inhibit by 50% the peripheral bronchospasm elicited by histamine at 10 micrograms/kg i.v. (antihistamine ED50). The second generation antihistamines studied were astemizole (CAS 68844-77-9), carebastine (CAS 90729-42-3), cetirizine hydrochloride (CAS 83881-52-1), ebastine (CAS 90729-43-4), norastemizole (CAS 75970-99-9), terfenadine (CAS 50679-08-8) and terfenadine carboxylate (CAS 83799-24-0). The second generation antihistamines astemizole, ebastine and terfenadine produced pronounced dose-dependent QTc interval prolongation effects. These arrhythmogenic effects occurred at doses that were between 1 and 4 times their respective peripheral antihistamine doses. These drugs produced significant disruption of the ECG wave form including large amplitude, morphologically aberrant T-waves and, in some cases, torsades de pointes-type arrhythmias. In contrast, terfenadine carboxylate (100 mg/kg i.v.), norastemizole (20 mg/kg, i.v.) and carebastine (50 mg/kg, i.v.), the major metabolites of terfenadine, astemizole and ebastine, were largely devoid of adverse ECG effects. Similarly, cetirizine (20 mg/kg, i.v.) was also found to not alter ECG or cardiovascular function. These findings demonstrate that terfenadine, astemizole and ebastine exhibit significant arrhythmogenic effects including QTc interval prolongation, bradycardia and distortion of the ECG morphology in the guinea pig. The relative cardiotoxicity of these antihistamines based on the separation of antihistamine activity and adverse ECG effects was similar for terfenadine and astemizole, but slightly less for ebastine. In this model carebastine, cetirizine, loratadine, norastemizole and terfenadine carboxylate are devoid of QTc prolongation effects. Given the structural similarity of terfenadine and ebastine it is not surprising that these drugs produce significant cardiotoxicity in this animal model. Taken together, these results indicate that the ability to cause QTc interval prolongation and the proclivity for producing arrhythmias is not a class effect and is seen only with some second generation nonsedating antihistamines.

Animals↗
PubMed1996

Long-term effects in two generations of enriched soybean and olive oil diets on some cardiovascular and biochemical parameters in male rats.

The effect of ingestion of enriched oil diets (soybean and olive) during two generations on some cardiovascular and biochemical parameters was measured in male rats. The animals (dams and pups) were fed with 3 different diets: standard diet, standard diet enriched with 7% of soybean oil and standard diet enriched with 7% of olive oil. At 2.5 months of age, male rats (first and second generation) after remaining in metabolic cages for a period of 10 days, were then anaesthetized, and body and heart weight, systolic, diastolic, mean blood pressure and heart rate, total-cholesterol, HDL-cholesterol, triglycerides, glucose and insulin were measured. Experimental diets produced over-weight only in the second generation. Blood pressure values were within normal limits, but in animals eating soybean oil these parameters were significantly increased in the second generation. While the concentrations of cholesterol, triglycerides and insulin in the second generation were significantly greater in experimental animals, and the concentrations of HDL-cholesterol and glucose were lower than in the controls, only the concentration of insulin was significantly greater in the experimental animals in the first generation. Plasmatic value of cholesterol was significantly increased in animals eating olive oil and plasmatic value of glucose was significantly decreased in animals eating soybean oil in the first generation. These results suggest that chronic ingestion of enriched oil diets negatively affects a number of key parameters implicated in the regulation of lipid and carbohydrate metabolism in male rats.

Animals↗
PubMed1997

CTL generation in the presence of IL-4 is inhibited by free p40: evidence for early and late IL-12 function.

The cytokine requirements for the generation of a CTL response were examined using thymocyte responders stimulated with Con A. In agreement with previous reports, IL-4 alone can generate a strong CTL response. To determine whether IL-12 was required for this response, we added either a neutralizing Ab against IL-12 or an antagonist of IL-12 function, p40. Both anti-IL-12 and p40 were found to inhibit the generation of CTL in the presence of IL-4. Consistent with these data, exogenous IL-12 was found to synergize with IL-4, particularly, when IL-4 was added at levels unable to generate a CTL response alone. This synergistic response was observed whether IL-12 was added at the beginning of culture along with IL-4 or after the first day to cultures initiated with IL-4. Likewise, the combination of IL-2 plus IL-12 evoked a strong synergistic response when cultures were initiated with IL-2 and IL-12 was added initially or after the first day of culture. Addition of either IL-2 or IL-12 alone did not generate a response. In contrast to these data showing that IL-12 was able to signal late in culture, p40 inhibited CTL generation in response to IL-4 only when added at the beginning of culture. These results imply that CTL induction involves a crucial early IL-12 signal, which once delivered permits cells to respond to a later IL-12 signal. These data are consistent with the idea that free circulating p40 could inhibit the generation of CTL by antagonizing the early IL-12 "differentiation" signal.

Animals↗
PubMedDate not supplied

Mononuclear blood cell sulfidoleukotriene generation in the presence of interleukin-3 and whole blood histamine release in honey bee and yellow jacket venom allergy.

Cross-linking IgE on basophils is known to cause both sulfidoleukotriene (sLT) generation and histamine release. We recently developed an ELISA to determine sulfidoleukotriene generation by blood mononuclear cells which employs pretreatment with IL-3 to enhance leukotriene generation (cellular antigen stimulation test, CAST). Here, we compared the CAST and whole blood histamine release in response to honey bee/yellow jacket venom (BV/YJV) in 23 patients clinically suspected of type-I allergy to these venoms. Of these, 17 were diagnosed as "definitive venom allergics," defined by a positive skin test at 100 ng/ml of venom or less. The six in whom such skin reactivity was absent were labelled "suspected venom allergics." Both venoms stimulated sulfidoleukotriene generation and histamine release also from control individuals (n = 10). In patients, insect venoms generally stimulated histamine release and sulfidoleukotriene generation in excess of the mean + 3 SD of values obtained with control individuals. However, about half of the patients reacted predominantly with either histamine release or sulfidoleukotriene generation. No overall correlation was found between threshold doses necessary to stimulate sulfidoleukotriene generation (ThsLT) and histamine release (ThHist). (Linear correlation coefficients between ThsLT and ThHist were -0.02 for honey bee venom and 0.13 for yellow jacket, n = 23). Both findings are in contrast to the concept that these responses occur in parallel. From results with "definitive venom allergics," CAST sensitivity was calculated as 100% for honey bee venom and 83% for yellow jacket, and that of the histamine release assay as 62.5% for honey bee venom and 50% for yellow jacket. Specificity of the CAST was calculated as 77% for honey bee venom and 100% for yellow jacket, and that of the histamine release assay as 44% for honey bee venom and 60% for yellow jacket. Thus, CAST results are closer to skin test results than to those of the whole blood histamine release assay.

Animals↗
PubMed1997

Multicenter evaluation of a second-generation assay for cardiac troponin T.

We report on the evaluation of the second-generation assay for cardiac troponin T (cTnT) on the Enzymun system. This new assay is completely specific for the cardiac isoform of TnT, utilizing two cardiospecific monoclonal antibodies. The assay time is reduced to 45 min. The interassay precision shows a median CV of 5.5%; 20% interassay CV was found between 0.05 and 0.1 microg/L. The cardiosensitivity of the second-generation cTnT assay in patients with ischemic myocardial injury appears equivalent when compared with the first-generation assay. We found no falsely positive results in patients with skeletal muscle damage including multitraumas, surgery patients, and marathon runners who showed highly increased values with the unspecific first-generation assay. In Duchenne disease cTnT was still increased, but to a much lower extent. cTnT remains increased in renal failure, but to a lesser degree than with the first-generation assay. The cause of this increase remains unclear. Although a cross-reactivity of skeletal muscle TnT in the second-generation assay could be excluded by our findings, minor myocardial damage or expression of the cardiac isoform of TnT in regenerating muscles cannot be ruled out in those cases with apparently falsely increased cTnT values. The second-generation cTnT assay is a step forward in the combination of cardiosensitivity and cardiospecificity in biochemical markers for diagnosis of heart disease.

Artifacts↗