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E Roux

Publications and source records attributed to E Roux.

At least 19 recordsLinked to original sources
PubMed2000

Recovery of immune reactivity after T-cell-depleted bone marrow transplantation depends on thymic activity.

To evaluate the importance of the thymus for the reconstitution of immunity in recipients of a T-cell-depleted bone marrow, we measured the appearance of CD4(+)CD45RA(+)RO(-) naive T cells (thymic rebound), restoration of the diversity of the T-cell-receptor (TCR) repertoire and the response to vaccinations with tetanus toxoid (TT). Repopulation by CD4(+)CD45RA(+)RO(-) thymic emigrants varied among patients, starting at approximately 6 months after transplantation. Young patients reconstituted swiftly, whereas in older patients, the recovery of normal numbers of naive CD4(+) T cells could take several years. Restoration of TCR diversity was correlated with the number of naive CD4(+)CD45RA(+)RO(-) T cells. Moreover, the extent of the thymic rebound correlated with the patient's capacity to respond to vaccinations. Patients without a significant thymic rebound at the moment of vaccination (CD4(+)CD45RA(+)RO(-) T cells less than 30 microL) did not respond, or responded only marginally even after 3 boosts with TT. We conclude that during the first year after transplantation, the absence of an immune response is due mainly to the loss of an adequate T-cell repertoire. Restoration of the repertoire can come only from a thymic rebound that can be monitored by measuring the increase of CD4(+)CD45RA(+)RO(-) naive T cells. This will allow postponing revaccinations to a moment when the patient will be able to respond more effectively. This may be particularly useful in the elderly patient who, owing to low thymic activity, might not yet be able to respond 1 year after transplant when revaccinations are usually scheduled.

Adolescent↗
PubMed2000

In vivo generation of human dendritic cell subsets by Flt3 ligand.

Dendritic cells (DCs) represent a family of ontogenically distinct leukocytes involved in immune response regulation. The ability of DCs to stimulate T-cell immunity has led to their use as vectors for immunotherapy vaccines. However, it is unclear whether and to what degree in vitro-generated DCs are representative of DCs that develop in vivo. Treatment of mice with human Flt3 ligand (FL) dramatically increases the number of DCs. We report here that administration of FL to healthy human volunteers increased the number of circulating CD11c(+ )IL-3Ralpha(low) DC (mean 44-fold) and CD11c(-) IL-3Ralpha(high) DC precursors (mean 12-fold). Moreover, the CD11c(+ )DCs were efficient stimulators of T cells in vitro. Thus, FL can expand the number of circulating, functionally competent human DCs in vivo.

Adjuvants, Immunologic↗
PubMed2000

Cellular mechanisms of acrolein-induced alteration in calcium signaling in airway smooth muscle.

Acrolein, an unsaturated aliphatic aldehyde, is a potent respiratory irritant. We have previously observed that acrolein administered ex vivo to isolated airways alters subsequent airway responsiveness to muscarinic agonists in terms of both mechanical activity of rings and calcium signaling in isolated cells. In the present study, we have examined the mechanisms by which acrolein alters Ca(2+) signaling. In freshly isolated rat tracheal smooth muscle cells, preexposure to acrolein increased the [Ca(2+)](i) oscillation frequency in response to endothelin 1 (ET-1, 0.1 microM), a contractile agonist that acts via the activation of a receptor different from the muscarinic cholinoceptor. We then studied acrolein-induced alteration in cell signaling with special attention to the steps downstream of membrane receptor activation i.e., the inositol 1,4,5-trisphosphate (InsP(3)) signaling pathway. Pretreatment of cells with LiCl (20 mM), a modulator of InsP(3) concentration, mimicked the effect of acrolein exposure on agonist-induced [Ca(2+)](i) response, i.e., increased the amplitude of the first Ca(2+) rise and the oscillation frequency in response to 0.1 and 10 microM acetylcholine (ACh), respectively. Moreover, in tracheal smooth muscle, preexposure to acrolein significantly increased carbachol-induced [(3)H]inositol-phosphates accumulation, up to 34 +/- 11% above unexposed tissue values. Finally, in beta-escin permeabilized cells, injection of InsP(3) (0.1-10 microM) induced a concentration-dependent [Ca(2+)](i) rise followed, for high InsP(3) concentration, by [Ca(2+)](i) oscillations, a calcium response whose pattern was similar to that induced by ACh. Exposure to acrolein did not alter the InsP(3)-induced [Ca(2+)](i) response. These results indicate that the effect of acrolein exposure on Ca(2+) responses in airway smooth muscle is not restricted to activation of the muscarinic cholinoceptor and is due to an enhancement in agonist-induced InsP(3) production. Since acrolein does not modify InsP(3) receptor channel sensitivity, we conclude that acrolein-induced alteration in calcium signaling can be ascribed to its sole effect on InsP(3) production.

Acrolein↗
PubMed2000

Human isolated bronchial smooth muscle contains functional ryanodine/caffeine-sensitive Ca-release channels.

Human bronchial smooth muscle (HBSM) contraction is implicated in a variety of respiratory diseases, including asthma. Yet, the presence of an operative calcium-induced calcium release (CICR) mechanism, identified in various smooth muscles, has not been established in HBSM. We therefore studied Ca-releasing mechanisms in HBSM obtained at thoracotomy with special attention to ryanodine-sensitive receptor channels (RyRs). In freshly isolated bronchial myocytes, ryanodine (0.5 to 50 microM) and caffeine (1 to 25 mM) induced transient increases in the cytoplasmic calcium concentration ([Ca(2+)](i)). Higher ryanodine concentrations (> 100 microM) inhibited the caffeine-induced [Ca(2+)](i) response, which was also blocked in the presence of tetracaine (300 microM) or ruthenium red (200 microM), two potent CICR inhibitors. In HBSM strips, caffeine induced a transient contraction which, likewise, was inhibited by ryanodine and tetracaine. However, ryanodine (200 microM) modified neither the [Ca(2+)](i) response nor the contraction induced by K(+)-rich (110 mM) solution. Reverse transcriptase/polymerase chain reaction (RT-PCR) and RNase protection assay performed in HBSM have revealed the existence of mRNAs encoding only the type 3 RyR. We also characterized acetylcholine-induced [Ca(2+)](i) and contractile responses. None of these responses was altered by ryanodine or by tetracaine. These results demonstrate, for the first time, the existence of functional RyRs in HBSM cells which, owing to the type of isoform or the amount of protein expressed, are not involved, under physiologic conditions, in depolarization- or agonist-induced contraction.

Acetylcholine↗
PubMed1999

CD45 isoform phenotypes of human T cells: CD4(+)CD45RA(-)RO(+) memory T cells re-acquire CD45RA without losing CD45RO.

We have studied the alterations in CD45R phenotypes of CD4(+)CD45RA(-)RO(+) T cells in recipients of T cell-depleted bone marrow grafts. These patients are convenient models because early after transplantation, their T cell compartment is repopulated through expansion of mature T cells and contains only cells with a memory phenotype. In addition, re-expression of CD45RA by former CD4(+)CD45RA(-) T cells can be accurately monitored in the pool of recipient T cells that, in the absence of recipient stem cells, can not be replenished with CD45RA(+) T cells through the thymic pathway. We found that CD4(+)CD45RA(-)RO(+) recipient T cells could re-express CD45RA but never reverted to a genuine CD4(+)CD45RA(+)RO(-) naive phenotype. Even 5 years after transplantation, they still co-expressed CD45RO. In addition, the level of CD45RA and CD45RC expression was lower ( approximately 35 %) than that of naive cells. In contrast, the level of CD45RB expression was comparable to that of naive cells. We conclude that CD4(+)CD45RA(-)RO(+) T cells may re-express CD45(high) isoforms but remain distinguishable from naive cells by their lower expression of CD45RA / RC and co-expression of CD45RO. Therefore, it is likely that the long-lived memory T cell will be found in the population expressing both low and high molecular CD45 isoforms.

Adult↗
PubMed1999

Effect of chronic hypoxia on calcium signalling in airway smooth muscle cells.

Chronic hypoxia (CH) alters smooth muscle contractility. CH generally produces a sustained attenuation of vasoreactivity. In airways, this effect of CH is poorly understood although CH is frequently observed in patients with pulmonary diseases. This study was designed to examine the effect of CH on both the isometric contraction of isolated rings and the cytosolic calcium concentration ([Ca2+]i) using microspectrofluorimetry in freshly isolated cells from rat tracheal smooth muscle. Tissues were obtained from both chronically hypoxic rats maintained in a hypobaric chamber (50.5 kPa) for 15 days and normoxic animals. CH increased the sensitivity of airway smooth muscle to cholinergic agonists. This increase observed in the mechanical activity (concentration of carbachol producing 50% of the maximal force (EC50) in tissues from normoxic and hypoxic animals: 0.80 microM (0.39-1.21 microM) and 0.34 microM (0.08-0.59 microM), respectively, p<0.05) was related to an increase in the sensitivity of cholinergic-mediated Ca2+ release (acetylcholine EC50 in cells from normoxic and hypoxic animals: 0.14 microM (0.11-0.17 microM) and 0.04 microM (0.026-0.054 microM), respectively, p<0.05). It was concluded that chronic hypoxia alters calcium signalling in airway smooth muscle cells, which was associated with an increase in airway responsiveness in vitro. Whether a similar phenomenon contributes to bronchial hyperresponsiveness in chronically hypoxaemic patients remains to be established.

Acetylcholine↗
PubMed1999

Human isolated airway contraction: interaction between air pollutants and passive sensitization.

Although there is epidemiological evidence that an increase in allergic diseases such as asthma may be linked to air pollution, there is little experimental data to address this issue. The aim of this study was thus to investigate the interaction between passive sensitization and exposure to pollutants in human isolated airways. We have examined (1) the effect of a preexposure to pollutants on the contraction of sensitized bronchi to a specific antigen, and (2) the effect of passive sensitization on the contraction to nonspecific agonists in bronchi preexposed to pollutants. In tissues sensitized by incubation in sera from asthmatic patients, preexposure to 0.3 microM acrolein (an aldehyde) for 10 min or 20 min significantly increased the maximal contractile response to the antigen Dermatophagoides pteronyssinus (D. pter.) by 20.5 +/- 6.5 and 34.9 +/- 7.4%, respectively. Similarly, preexposure to ozone (1 ppm for 20 min) increased the response to D. pter. by 25.3 +/- 11.3%. On the other hand, passive sensitization increased the contractile response to carbachol or histamine of bronchial rings preexposed to 0.3 microM acrolein for 10 min by 33.5 +/- 6.2% and 32.5 +/- 5.1%, respectively. This study provides a proof of principle in vitro for a combined effect of immunological sensitization and exposure to pollutants, i.e., passive sensitization and exposure to pollutants act in a synergistic manner on human bronchial smooth muscle reactivity in response to both specific antigen and nonspecific agonists.

Acrolein↗
PubMed1998

Reconstitution of the T-cell compartment after bone marrow transplantation: restoration of the repertoire by thymic emigrants.

We have studied the reconstitution of the T-cell compartment after bone marrow transplantation (BMT) in five patients who received a graft-versus-host disease (GVHD) prophylaxis consisting of methotrexate, cyclosporin, and 10 daily injections (day -4 to day +5) of Campath-1G. This treatment eliminated virtually all T cells (7 +/- 8 T cells/microL at day 14) which facilitated the analysis of the thymus-dependent and independent pathways of T-cell regeneration. During the first 6 months, the peripheral T-cell pool was repopulated exclusively through expansion of residual T cells with all CD4(+) T cells expressing the CD45RO-memory marker. In two patients, the expansion was extensive and within 2 months, the total number of T cells (CD8>>CD4) exceeded 1,000/microL. In the other three patients, T cells remained low (87 +/- 64 T cells/microL at 6 months) and remained below normal values during the 2 years of the study. In all patients, the first CD4(+)CD45RA+RO- T cells appeared after 6 months and accumulated thereafter. In the youngest patient (age 13), the increase was relatively fast and naive CD4(+) T cells reached normal levels (600 T cells/microL) 1 year later. In the four adult patients (age 25 +/- 5), the levels reached at that time-point were significantly lower (71 +/- 50 T cells/microL). In all patients, the T-cell repertoire that had been very limited, diversified with the advent of the CD4(+)CD45RA+RO- T cells. Cell sorting experiments showed that this could be attributed to the complexity of the T-cell repertoire of the CD4(+)CD45RA+RO- T cells that was comparable to that of a normal individual and that, therefore, it is likely that these cells are thymic emigrants. We conclude that after BMT, the thymus is essential for the restoration of the T-cell repertoire. Because the thymic activity is restored with a lag time of approximately 6 months, this might explain why, in particular in recipients of a T-cell-depleted graft, immune recovery is delayed.

Adolescent↗
PubMed1998

Muscarinic stimulation of airway smooth muscle cells.

1. Acetylcholine, the principal neurotransmitter of the parasympathetic nervous system, is released at both ganglionic synapses and postganglionic neuroeffector junctions and acts by activation of nicotinic and muscarinic cholinoceptors. This review focuses on the effects of postjunctional muscarinic stimulation of airway smooth muscle. 2. On pharmacological criteria, four distinct subtypes of muscarinic cholinoceptor, denoted M1, M2, M3 and M4 receptors, have been identified by use of selective antagonists. Cloned muscarinic cholinoceptors are members of the family of GTP-binding protein-coupled receptors, which are characterized by seven transmembrane (TM) regions connected by intra- and extracellular loops. Between the fifth and the sixth TM regions, muscarinic receptors possess a large intracytoplasmic loop that is considered to be responsible for G-protein-coupling selectivity and exhibits high divergence between the different subtypes. 3. At the site of the smooth muscle itself, both binding and Northern blot studies have demonstrated, in a variety of species, that muscarinic receptor subtypes present are M2 and M3. M2 receptors are coupled to Gi proteins and adenylyl cyclase inhibition and thus to cAMP signaling. M3 receptors are coupled to Gq/11 protein and phosphoinositide hydrolysis and thus to calcium signaling. 4. Muscarinic-induced contraction of airway smooth muscle is mediated by M3 receptors. M2-mediated inhibition of adenylyl cyclase contributes to the prevention of bronchodilation. Cross-talk between muscarinic and beta2 adrenoceptors is likely to be present in airway smooth muscle. The pathophysiological role of this cross-talk requires further investigation.

Cholinergic Agents↗
PubMed1998

A cell cycle regulating receptor is localized on cell surface and in nuclei of mitotically and meiotically dividing cells.

We previously showed that a heterodimeric surface receptor of molecular weight 65,000 (p65) and 95,000 (p95) is expressed on the surface of proliferating cells such as activated T lymphocytes and neural precursors. This p65/p95 receptor is recognized by a monoclonal antibody and by type 3 reovirus hemagglutinin. Binding of the surface p65/p95 receptor leads to a growth arrest of mitotic cells and a consequent inhibition of proliferation. The p65/p95 receptor was demonstrated to be associated with kinase activity. Because p65/p95 is involved in the regulation of mitotic cell division, we sought to study the cellular distribution of the receptor and its possible role in meiotic cell division. Immunohistochemical labeling and flow cytometry studies were done using adult rat testes and cell lines. All cells undergoing mitotic or meiotic division in the rat testis expressed the p65/p95 receptor; cells that do not divide did not express receptors. Dividing cells had two receptor pools. As previously reported for several mitotically active tissues, a pool of receptors was localized on the cell surface. Interestingly, a pool of receptors was also seen intracellularly over the nucleus of labeled cells. The nuclear label seemed to be associated with chromosomes during specific stages of the mitotic and the two meiotic divisions, suggesting a role in the regulation of nuclear events. Further studies on this receptor and the function of the nuclear pool should provide a better understanding of the control of cell division.

Age Factors↗
PubMed1998

Effects of intravenous anesthetics on normal and passively sensitized human isolated airway smooth muscle.

BACKGROUND: General anesthetics may modify airway responsiveness. The authors investigated the effect of thiopental, propofol, and etomidate on airway smooth muscle. METHODS: Contraction experiments were done in human airway rings that were either normal or passively sensitized with asthmatic serum. The effect of propofol and etomidate was also studied on both [Ca2+]i increase measured by microspectrofluorimetry in isolated myocytes and isometric contraction in the rat trachea. RESULTS: In human bronchi, thiopental (10[-7] to 10[-4] M) induced a concentration-dependent contraction. Neither propofol nor etomidate altered baseline tone, but both anesthetics reduced histamine-induced contraction. In human immunologically sensitized isolated bronchi, propofol (3 x 10[-4] M) reduced histamine reactivity (deltaFmax in %) to a greater degree than in nonsensitized tissues (64.4 +/- 15.7% and 16.4 +/- 8.5%, respectively; n = 6, P < 0.05), whereas the effect of etomidate (10[-4] M) was similar in both types of tissue (24.1 +/- 6% and 22.3 +/- 15%, respectively, n = 6). In rat isolated tracheal myocytes, propofol (3 x 10[-4] M) and etomidate (10[-4] M) altered the [Ca2+]i signal in response to the depolarizing agent potassium chloride and the muscarinic agonist acetylcholine. Accordingly, the two anesthetics also reduced the mechanical response of rat tracheal rings to these agonists. CONCLUSIONS: Whereas thiopental contracts human isolated bronchi, propofol and etomidate reduce histamine-induced contraction in human isolated airway smooth muscle that were either not sensitized or passively sensitized with asthmatic serum. This effect involves inhibition of both electro- and pharmacomechanical coupling.

Anesthetics, Intravenous↗
PubMed1998

Calcium signaling in airway smooth muscle cells is altered by in vitro exposure to the aldehyde acrolein.

We have previously observed that acrolein administered ex vivo to isolated airways alters the subsequent airway responsiveness. To examine the cellular mechanisms involved in this alteration, we have studied the effect of acrolein exposure on calcium signaling in myocytes freshly isolated from rat trachea. We have also studied the effect of acrolein exposure on isometric contraction of rat epithelium-free tracheal rings. Tissues were exposed to a variety of acrolein concentrations from 0.1 to 1 microM and durations from 5 to 15 min. In isolated cells, exposure to acrolein did not modify the resting cytosolic Ca2+ concentration ([Ca2+]i) whatever the concentration or duration of exposure, but altered the pattern of the Ca2+ response to acetylcholine (ACh). ACh typically induces an initial [Ca2+]i rise followed by peaks of decreasing amplitude (oscillations). Exposure to a fixed concentration of acrolein (0.2 microM) for 5 and 10 min significantly enhanced the amplitude of the initial [Ca2+]i rise in response to a low concentration of ACh (0.1 microM) by 50.8 and 77%, respectively. Similarly, exposure for a fixed duration of 10 min significantly enhanced the amplitude of the initial [Ca2+]i rise by 49.4% at an acrolein concentration of 0.3 microM. When cells were stimulated with a high ACh concentration (10 microM), the value of the first [Ca2+]i peak was not changed by acrolein exposure; but the frequency at which subsequent peaks occurred was significantly increased by 44.4% after 10 min of exposure to a fixed concentration of 0.2 microM and by 36.3% following an exposure for a fixed duration of 10 min at the concentration of 0.3 microM. In contrast, acrolein, whatever the concentration, had no effect on the caffeine-induced [Ca2+]i response. In rat epithelium-free tracheal rings, acrolein increased the response to muscarinic stimulation, with a maximal effect observed for an exposure to 0.3 microM for 10 min. The effect of acrolein on the [Ca2+]i response of isolated myocytes occurred over a range of doses similar to that on the contractile response of rings, suggesting that the effect of this pollutant on calcium signaling may account, at least partially, for acrolein-induced airway hyperresponsiveness.

Acetylcholine↗
PubMed1997

Fate of hamster oviductin in the oviduct and uterus during early gestation.

Oviductins are a family of glycoproteins which are synthesized and secreted by oviductal secretory cells and which, upon their secretion in the lumen of the oviduct, become associated with postovulatory oocytes and developing embryos. Recently, we showed that hamster oviductin is maximally secreted in the oviduct at the time of ovulation and is later associated with a certain population of uterine epithelial cells, where it is subsequently endocytosed and degraded. In light of these results, this study was conducted to follow the fate of hamster oviductin in the oviduct and uterus during early gestation. Using a monoclonal antibody against hamster oviductin, immunofluorescence and immunogold labeling revealed that during early gestation, immunoreactivity to oviductin in the uterus gradually diminished to an almost total disappearance at time of implantation. However, the strong labeling intensity remained unchanged in the oviduct. Biochemical analyses demonstrated that a degradation of oviductin occurs in the uterus, and a loss of immunoreactivity was also observed as gestation progressed, so that by the time of implantation, immunoreactivity to oviductin was barely detectable. The decrease of oviductin along the uterine epithelium at the time of blastocyst attachment and its final disappearance at implantation suggest that this glycoprotein could be a potential modulator of uterine receptivity.

Animals↗
PubMed1997

[Ca2+]i oscillations induced by muscarinic stimulation in airway smooth muscle cells: receptor subtypes and correlation with the mechanical activity.

1. Cytosolic calcium concentration ([Ca2+]i) by indo 1 microspectrofluorimetry in freshly isolated cells and isometric contraction of isolated rings were measured in response to muscarinic cholinoceptor stimulation in rat tracheal smooth muscle. 2. In isolated myocytes, acetylcholine (ACh, 0.03-1 microM) caused a rapid and graded increase in [Ca2+]i up to a net amplitude of 492 +/- 26 nM (n = 19) which gradually declined. The EC50 for ACh was 0.13 microM. This first [Ca2+]i peak was followed, when the ACh concentration increased, in approximately 50-60% of the cells, by successive peaks of decreased amplitude ([Ca2+]i oscillations) superimposed on the plateau phase. Whereas the percentage of cells exhibiting [Ca2+]i oscillations remained consistent, the frequency of these oscillations increased to up to 10 min-1 with an ACh concentration of 100 microM. 3. Removal of extracellular calcium (in the presence of EGTA, 0.4 mM) or addition of the voltage-dependent Ca(2+)-channel blocker verapamil (10 microM) did not alter the first [Ca2+]i peak, the plateau or the oscillations induced by ACh or carbachol. In contrast, the specific inhibitor of the sarcoplasmic Ca(2+)-ATPase, thapsigargin (1 microM), completely abolished the [Ca2+]i response. Thapsigargin (1 microM) also blocked the caffeine (5 mM)-induced transient rise in [Ca2+]i. 4. Atropine (a non-selective muscarinic cholinoceptor antagonist) and 4-diphenyl acetoxy N-methyl piperidine (4-DAMP, a selective M3 antagonist) inhibited the [Ca2+]i response to muscarinic cholinoceptor activation with an IC50 of 13 and 20 nM, respectively. Pirenzepine (a selective M1 antagonist) also totally inhibited the [Ca2+]i response to ACh but with a higher IC50 of 2 microM. Methoctramine (a selective M2 antagonist) up to a concentration of 10 microM caused only a 40% inhibition. The effect of muscarinic antagonists on cumulative concentration-response curves (CCRC) for carbachol was assessed at the following concentrations: atropine and 4-DAMP at 3, 10 and 30 nM; pirenzepine 0.3, 1 and 3 microM, and methoctramine at 1, 3 and 10 microM. For these concentrations, all of the antagonists produced a rightward shift of the CCRC for carbachol and pA2 values were 9.2, 8.8, 6.7 and 6.3, respectively. 5. In conclusion, the present study indicates that muscarinic stimulation of rat isolated tracheal smooth muscle cells induces [Ca2+]i oscillations. The occurrence of these oscillations depends on the graded amplitude of the first [Ca2+]i rise and their frequency may play a role in the amplitude of the mechanical activity in response to muscarinic cholinoceptor activation. Both the [Ca2+]i and the contractile responses are primarily dependent on activation of the M3 receptor subtype.

Acetylcholine↗