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B Descamps-Latscha

Publications and source records attributed to B Descamps-Latscha.

At least 73 records · Page 4Linked to original sources
PubMed1991

Molecular characteristics of cytochrome b558 isolated from human granulocytes, monocytes and HL60 and U937 cells differentiated into monocyte/macrophages.

Enriched cytochrome b558 preparations were obtained from human mature monocytes (MN) and retinoic acid plus interferon gamma induced human myeloid leukemia cell lines HL-60 and U937, using an adaptation of the procedure described by A.W. Segal (Nature (1987) 326, 88-91) for purification of cytochrome b558 from human polymorphonuclear leukocytes (PMN). Spectral characteristics of cytochrome b558 were determined and found to be independent of cell type and specific heme b content of the preparation. To increase the sensitivity of the spectral assay, analysis in the gamma band were used and delta epsilon 427-413 was determined to be equal to 158 mM-1 cm-1. An alpha beta type heterodimeric cytochrome b558 was found for PMN and MN by the concordant elution of heme b spectral activity from heparin agarose and the detection of two polypeptide chains by SDS-PAGE. The expression of the lighter polypeptide alpha chain in the various human monocyte-like cell lines was assessed and its identity, as a component of cytochrome b, was confirmed by immunodetection using a rabbit polyclonal antibody reacting with the alpha subunit of PMN cytochrome b558. Immunoblotting studies detected the alpha subunit in monocyto-macrophagic differentiated HL-60 and U 937 cells and mature MN at 22 kDa, but not in uninduced cells which did not express the respiratory burst. Whatever the specific content or the cell origin of the cytochrome b558-enriched preparations, the heme b binding site was shown to be associated with the alpha subunit defined by a constant molecular mass of 22 kDa, as evidenced by the finding of a constant ratio between the silver stained band intensity and the corresponding heme b amount. The heavy polypeptide beta chain from MN cytochrome b was found to have a significantly higher molecular weight than the beta subunit from PMN at 94 +/- 5 kDa instead of 90 +/- 4 kDa. In contrast, in cytochrome b preparations from induced monocyto-macrophagic cells, isolated with a low heme specific content, the variability in the detection of the staining intensity of the beta band either in SDS-PAGE or immunodetection reactivities precludes accurate definition of its molecular mass and estimation of the stoichiometry between the alpha and beta subunits in the differentiated cells. However, wheat-germ agglutinin binding studies indicated the presence of N-glycosylated protein in the range of 85-110 kDa.

Cell Differentiation↗
PubMed1991

Structural modifications of human beta 2 microglobulin treated with oxygen-derived radicals.

Treatment of human beta 2 microglobulin (beta 2m) with defined oxygen-derived species generated by treatment with gamma-radiation was studied. As assessed by SDS/PAGE, the hydroxyl radicals (.OH) caused the disappearance of the protein band at 12 kDa that represents beta 2m, and cross-linked the protein into protein bands stable to both SDS and reducing conditions. However, when .OH was generated under oxygen in equimolar combination with the superoxide anion radical (O2.-), the high-molecular-mass protein products were less represented, and fragmented derivatives were not obviously detectable. Exposure to .OH alone, or to .OH + O2.- in the presence of O2, induced the formation of beta 2m protein derivatives with a more acidic net electrical charge than the parent molecule. In contrast, O2.- alone had virtually no effect on molecular mass or pI. Changes in u.v. fluorescence during .OH attack indicated changes in conformation, as confirmed by c.d. spectrometry. A high concentration of radicals caused the disappearance of the beta-pleated sheet structure and the formation of a random coil structure. Loss of tryptophan and significant production of dityrosine (2,2'-biphenol type) were noted, exhibiting a clear dose-dependence with .OH alone or with .OH + O2.-. The combination of .OH + O2.- induced a pattern of changes similar to that with .OH alone, but more extensive for c.d. and tryptophan oxidation (2 Trp/beta 2m molecule), and more limited for dityrosine formation. Lower levels of these oxidative agents caused the reproducible formation of species at 18 and 25 kDa which were recognized by antibodies against native beta 2m. These findings provide a model for the protein pattern observed in beta 2m amyloidosis described in the literature.

Amino Acids↗
PubMed1991

A monoclonal antibody against peripheral benzodiazepine receptor activities the human neutrophil NADPH-oxidase.

A murine monoclonal antibody, mAb 8523, raised against whole human pro-monocytic U937 cells recognizes an 18 kDa antigen in human neutrophils (PMN), as determined by immunoprecipitation and by immunodetection on Western blots of SDS-PAGE of PMN membrane fractions. That is 18 kDa antigen corresponds to the phagocyte peripheral benzodiazepine receptor (PBZDR) is evidenced by its co-migration with the 18 kDa covalently labeled PBZDR, detected by autoradiography, and their co-modulation upon phorbol-myristate-acetate activation of PMN. Purified mAb 8523 (IgG2b) is able to dose-dependently and specifically stimulate both the basal and the FMLP-induced oxidative burst of intact human PMN, assessed by luminol-amplified chemiluminescence. This property of the first described monoclonal antibody against PBZDR supports the implication of this receptor in NADPH-oxidase activation and consequently in phagocyte-dependent host defense mechanisms.

Antibodies, Monoclonal↗
PubMed1991

Benzodiazepine anesthesia in humans modulates the interleukin-1 beta, tumor necrosis factor-alpha and interleukin-6 responses of blood monocytes.

The influence of sedative and anxiolytic benzodiazepines on human monocyte function was assessed in 11 patients undergoing anesthesia prior to control endoscopy of the urinary tract. A single i.v. injection of 0.08 mg/kg midazolam induced a marked and delayed inhibition of the lipopolysaccharide-induced production of interleukin-1 beta, tumor necrosis factor-alpha and interleukin-6 by monocytes isolated from peripheral blood. Corticosteroids were not responsible for the observed immunosuppression. These studies demonstrate that, when administered in man, benzodiazepines markedly alter the capacity of monocytes to synthetize major mediators of the host inflammatory response.

Anesthesia↗
PubMed1991

Elevated circulating levels of interleukin-6 in patients with chronic renal failure.

In a previous study, we demonstrated the presence of circulating interleukin-1 (IL-1) in long-term dialyzed patients and that of tumor necrosis factor alpha (TNF alpha) in both long-term and not yet dialyzed uremic patients. In the present study, we attempted to determine the respective influence of hemodialysis (HD) and uremia on the plasma level of interleukin-6 (IL-6), which shares several biological properties with IL-1 and TNF alpha, including the induction of the acute phase response of the inflammatory process. Forty-eight patients with end-stage renal failure, including 32 long-term HD patients and 16 chronic uremic patients undergoing their first dialysis session, were tested for plasma IL-6 using both biological and immunoreactive assays. Plasma IL-6 activity was significantly increased in patients with chronic renal failure (P less than 0.001) compared to its level in normal individuals. No difference was observed, however, between long-term and not yet dialyzed patients. In the patients with the most pronounced IL-6 activity, immunoreactive IL-6 levels between 60 and 150 pg/ml were detected. A monoclonal antibody (mAb) against human IL-6 inhibited the activity of plasma in the IL-6 bioassay, and a close correlation existed between the biological activity of IL-6 and its immunoreactive level. No change in plasma IL-6 was detected during the course of the first dialysis as well as subsequent sessions. Likewise, no influence of the nature (cellulosic or synthetic polyacrilonitrile) of the dialysis membrane equipping the dialyzer was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Assay↗
PubMed1991

Influence of first and long-term dialysis on uraemia-associated increased basal production of interleukin-1 and tumour necrosis factor alpha by circulating monocytes.

In a previous study we demonstrated the presence of circulating interleukin-1 (IL-1) in long-term haemodialysis patients and of tumour necrosis factor alpha (TNF alpha) in both long-term haemodialysis and not-yet-dialysed uraemic patients. The present report investigates the spontaneous capacity of monocytes to produce and secrete these two cytokines in 35 long-term haemodialysis patients and 36 uraemic patients undergoing their first dialysis session. Predialytic cell-associated IL-1 concentrations in freshly isolated monocytes were significantly increased both in long-term haemodialysis and first-dialysis uraemic patients compared to normal individuals. In both groups in comparison to normal individuals, although intracellular TNF alpha could not be detected in freshly isolated monocytes, both extracellular IL-1 and TNF alpha concentrations were greatly increased after 20 h of in vitro culture of monocytes in the absence of exogenous stimulation and in serum-free conditions. However, long-term haemodialysis patients showed higher values of secreted IL-1 than not-yet dialysed uraemic patients. During a single dialysis session a significant increase in both cell-associated and secreted IL-1 but not TNF alpha was observed in long-term haemodialysis patients. In contrast, no change in the concentration of either cytokine could be detected at the end of the first dialysis session in uraemic patients. Our findings strongly suggest that factors related to uraemia could be a sufficient signal to initiate intracellular IL-1 protein synthesis and TNF alpha release by monocytes, but that greater IL-1 release could be stimulated during the periodic haemodialysis procedure.

Cells, Cultured↗
PubMed1991

Establishing the relationship between complement activation and stimulation of phagocyte oxidative metabolism in hemodialyzed patients: a randomized prospective study.

The present prospective study was conducted in order to establish the relationship between complement activation and stimulation of phagocyte oxidative metabolism observed in long-term hemodialysis (HD) patients during the early phase of dialysis with cellulosic membranes. Two groups of 10 randomized (HD) patients treated with cellulosic (Cuprophan, CUP) or synthetic polyacrilonitrile (PAN AN-69) membranes were studied. Leukocyte counts, C3a antigen plasma concentration and whole blood basal and stimulated chemiluminescence (CL) production were determined in blood samples drawn from the fistula before dialysis (T0) and from both the afferent and efferent lines of the dialyser at 15 min (T15) and at the end (Tend) of the dialysis session. This study confirms that, coincident with the nadir of leukopenia observed at T15, dialysis with CUP but not PAN membranes induces a marked rise in C3a antigen levels and profound alterations in whole blood CL production consisting of a dramatic increase in basal CL and a significant loss in CL response capacity to stimulating agents. It further demonstrates that a direct relationship exists between the variations in C3a antigen plasma levels and whole blood CL production observed in the CUP group of patients from T0 to T15 (delta 15) of dialysis. This relationship is characterized by a positive correlation between delta 15 C3a and delta 15 basal CL levels in afferent and efferent lines, and a negative correlation between delta 15 C3a and delta 15 CL response capacity values in the efferent but not afferent line. In contrast, no significant correlation with the type of dialysis membrane could be demonstrated between the variations in polymorphonuclear neutrophil counts and C3a antigen levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylic Resins↗
PubMed1991

Endogenous anxiogenic peptide, ODN-diazepam-binding inhibitor, and benzodiazepines enhance the production of interleukin-1 and tumor necrosis factor by human monocytes.

Benzodiazepines (BZD) have been described to interact with specific peripheral-type receptors on phagocytes. The present study demonstrates that pico- to nanomolar concentrations of BZD compounds enhance the lipopolysaccharide (LPS)-induced production of tumor necrosis factor (TNF) and interleukin-1 (IL-1) by human monocytes, as determined by specific immunoreactive and biological assays for these cytokines. BZD remained ineffective in the absence of LPS. The activity of BZD was restricted to peripheral (Ro 5-4864) and mixed (diazepam, Valium) type ligands, while anxiogenic (beta-carbolines) or anxiolytic (clonazepam) central type ligands had no effect. Interestingly, peptide fragments of the endogenous anxiogenic ligand diazepam-binding inhibitor (DBI), such as octadecaneuropeptide (ODN-DBI) and the octaneuropeptide corresponding to its COOH-terminal sequence, very efficiently modulated the LPS-induced production of both monokines. Similar results were obtained directly within whole blood samples. These results indicate that widely prescribed pharmacological compounds and endogenous anxiety modulators affect molecular mediators of human host defense mechanisms and inflammatory reactions.

Anti-Anxiety Agents↗
PubMed1990

Altered expression of neutrophil peripheral benzodiazepine receptor in X-linked chronic granulomatous disease.

This study was aimed at determining whether the peripheral benzodiazepine receptor (PBZDR), which is abundantly expressed on mononuclear phagocytes, is involved in host defense mechanisms depending on phagocyte membrane-associated NADPH-oxidase complex. Analysis by reversible and covalent binding of PBZDR expression on human neutrophils shows that it is modulated during NADPH-oxidase activation with phorbol 12-myristate 13-acetate. Based on a series of 17 patients with chronic granulomatous disease (CGD), results show that PBZDR expression is dramatically impaired in X-linked CGD, an inherited disorder due to a mutation on the gene coding for cytochrome b558 NADPH-oxidase component, whereas it is unaffected in autosomal recessive CGD where cytochrome b558 is normally expressed, suggesting a link between PBZDR and cytochrome b558 expressions. PBZDR can be assigned by covalent binding to an 18-Kd membrane protein. These results suggest that the neutrophil PBZDR, which can accommodate the widely prescribed anxiolytic drug Valium (diazepam), is involved in host defense against pathogens, a function that could be affected by neuroimmune interactions.

Enzyme Activation↗
PubMed1990

Predictive value of whole blood chemiluminescence in patients with alcoholic hepatitis.

Recent reports suggest that ethanol metabolism leads to reactive oxygen intermediates that may be responsible for the lesions observed in alcoholic hepatitis. This study investigated the production of reactive oxygen intermediates in peripheral blood phagocytes of patients with alcoholic hepatitis and attempts to evaluate its predictive value. Using a luminol-dependent chemiluminescence method, reactive oxygen intermediate production was measured directly within microamounts of whole blood, both in the absence (basal chemiluminescence production) and in the presence of phagocyte-stimulating agents including latex, zymosan, phorbol myristate acetate and N-formyl-methionyl-leucyl-phenylalanine. Thirty patients with well-documented and histologically proven alcoholic hepatitis were studied. Pugh's and Child's classification, Orrego's composite clinical and laboratory index and Maddrey's discriminant function were used to assess the prognosis of the liver disease. Patients were followed up monthly for 6 mo. Results were compared with those obtained in 17 patients with nonalcoholic liver disease and in 78 normal control subjects. Basal chemiluminescence production was significantly higher in patients with alcoholic hepatitis than in those with nonalcoholic liver disease and in normal subjects (p less than 0.001). Chemiluminescence responses to latex, zymosan and phorbol myristate acetate were significantly lower in alcoholic hepatitis patients than in normal subjects (p less than 0.001); however, when compared with nonalcoholic liver disease patients, these responses were significantly decreased only in the presence of zymosan (p less than 0.05). Both basal chemiluminescence production (p less than 0.001) and zymosan-induced chemiluminescence responses (p less than 0.02) were closely related to alcoholic hepatitis prognosis indices (i.e., Pugh's and Child's classification, Orrego's composite clinical and laboratory index and Maddrey's discriminant function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Activation of phagocyte oxidative metabolism by opsonized Plasmodium falciparum merozoites.

A luminol-dependent chemiluminescence (CL) method was used to measure the oxidative burst of phagocytes triggered by antimalarial antibodies and Plasmodium falciparum merozoites. A specific antibody-dependent increase in chemiluminescence response was obtained using both polymorphonuclear leukocytes and monocytes as effector cells. Using various sera from malaria infected subjects it was observed that antibodies involved in the increased chemiluminescence responses were encountered at higher levels in sera from protected subjects than in those susceptible to clinical manifestations. In the conditions used the assay shows substantial intertest variation but appears of interest to assess the protective status of groups of exposed individuals.

Adolescent↗
PubMed1990

Phagocyte oxidative metabolism in cyclosporine- or placebo-treated patients with insulin-dependent (type I) diabetes mellitus of recent onset.

Several lines of evidence suggest that phagocyte-mediated oxidative processes are involved in damage to pancreatic islet cells of Type I insulin-dependent diabetes mellitus (IDDM). This hypothesis, however, has not yet been explored at the clinical onset of IDDM. Similarly, the possibility that cyclosporine A (Cy-A) might exert a selective influence on these phagocyte-mediated oxidative reactions has also not yet been investigated as compared to a placebo. The present study tested both hypotheses in 32 patients with recently diagnosed IDDM who were part of the recent French multicenter randomized therapeutic trial of Cy-A. The production of reactive oxygen intermediates (ROI) by circulating polymorphonuclear (PMN) and mononuclear (MN) phagocytes was determined by luminol-dependent chemiluminescence (CL), both directly within microamounts of whole blood and in purified PMN or MN phagocyte suspensions. Lastly, CL production was measured in the absence (resting CL) and the presence of a panel of particular and soluble phagocyte membrane-stimulating agents. We found that on entry into the trial, i.e. within less than 2 months of the clinical onset of IDDM, patients had normal whole blood CL production in the absence of a stimulating agent and upon phagocytic challenge with latex or opsonised zymosan particles. By contrast, whole blood CL responses to soluble stimuli such as phorbol myristate acetate (PMA), concanavalin A (Con-A) and F Met-Leu-Phe (FMLP) were significantly higher than in the control group of 52 normal subjects (P less than 0.01). In purified PMN and MN phagocyte suspensions, both resting and stimulated CL productions were normal, regardless of the type of stimulating agent. After 3 months of treatment, whole blood CL responses to Con-A and FMLP returned to almost normal levels in patients treated with Cy-A (15 cases) but not in those receiving the placebo (17 cases); PMA-induced CL responses were also decreased, but this was found in both groups of patients. In purified phagocyte suspensions we detected no effect of Cy-A on PMN, whereas MN phagocytes from Cy-A-treated patients showed reduced CL responses to FMLP but not to other stimuli. Altogether, these results demonstrate for the first time that the capacity of circulating PMN and MN phagocytes to generate ROI is normal at the clinical onset of IDDM and suggest that circulating substances increase oxidative responses to soluble, but not particulate, stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Influence of uremia and hemodialysis on circulating interleukin-1 and tumor necrosis factor alpha.

Interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) were determined in the plasma of long-term hemodialysis (HD) patients and uremic (UR) patients undergoing their first dialysis session using either cellulosic (CUP) or synthetic (PAN-AN 69) membrane-equipped dialyzers. In long-term HD patients, plasma IL-1 and TNF alpha levels were significantly increased compared to their levels in normal subjects. During a single dialysis session, a significant increase in IL-1 but not in TNF alpha was observed. In not yet dialyzed UR patients, IL-1 plasma levels did not differ from those observed in normal subjects. By contrast, TNF alpha was found significantly increased although less than in long-term HD patients. During the first dialysis session, no significant increase was observed in the levels of either monokine. Lastly, regardless of the group of patients, no significant influence of the dialysis membrane could be detected, suggesting that the observed changes are not exclusively secondary to the activation of complement. Altogether, these results suggest that the passage of the blood through the extracorporeal dialysis circuit triggers the secretion of IL-1 and further exacerbates that of TNF alpha by monocytes. The presence of increased TNF alpha in the plasma of first-dialysis UR patients suggests that factors unrelated to dialysis contribute to the activation of monocytes in these patients. Lastly, the concomitant presence of IL-1 and TNF alpha in the plasma of long-term HD patients could be responsible for some of the clinical features observed in these patients, and provides strong evidence favoring the concept that HD can be assimilated to a recurrent acute-phase inflammatory response.

Acrylic Resins↗
PubMed1990

Development of cytochrome b558 and oxidative metabolism in human granulocytes, monocytes and during differentiation of HL-60 and U 937 cells.

The development of cytochrome b558 (Cyt b) as determined spectrophotometrically, was investigated in human polymorphonuclear neutrophils (PMN), monocytes (MN) and during differentiation of HL-60 and U 937 cells induced by retinoic acid (RA) alone or in combination with IFN gamma. O2- release in response to a panel of stimulating agents, ie latex particles, opsonised zymosan, PMA, Con A and fMLP, was monitored by lucigenin-amplified chemiluminescence (CL). In parallel the expression of myeloperoxidase (MPO) was investigated and its catalytic activity on H2O2 related to luminol-amplified CL responses. In mature PMN and MN phagocytes, regardless of the stimulating agent, the O2- production is closely related to Cyt b but not to MPO specific contents. In differentiated HL-60 and U 937 cells, the oxidative metabolism increases in parallel with Cyt b specific contents, both being enhanced by the addition of IFN gamma to the RA treatment. However, marked differences in the O2- production intensities are observed depending on the stimulating agent tested and the state of differentiation considered. The PMA-stimulated O2- production is rather low ie 100 and 20 times less in granulocytic HL-60 and monocyto-macrophagic U 937 cells than in PMN and MN respectively. Latex, zymosan and Con A stimulated responses are close to those of MN, in monocyte-macrophagic U 937 cells. In conclusion, these data show that during differentiation; 1), Cyt b plays a critical role in O2- production; 2), the pathways leading to NADPH oxidase activation are diversely modulated following phagocyte differentiation with IFN gamma and/or with RA.

Acridines↗
PubMed1990

In vivo treatment with benzodiazepines inhibits murine phagocyte oxidative metabolism and production of interleukin 1, tumor necrosis factor and interleukin-6.

We reported previously that benzodiazepines, widely prescribed for their anxiolytic properties, bind to specific receptors on macrophages and modulate in vitro their metabolic oxidative responsiveness. This study was designed to investigate the in vivo effects of benzodiazepine molecules on several macrophage functions. Benzodiazepines injected i.p. exerted a long-lasting inhibition on phagocyte oxidative responsiveness, still detectable 48 hr after injection. This action was dose-dependent, optimally effective at 1 mg/kg and observed at the site of injection within peritoneal cells as well as at a distance, within splenocytes. It was restricted to peripheral and mixed-type molecules whereas the central-type compound, clonazepam, was ineffective, in good keeping with the molecular specificity of the receptor present on murine macrophages. The fact that benzodiazepines exerted similar effects in Nude mice highly suggests that their in vivo inhibitory activity was not T cell-dependent. The peripheral benzodiazepine Ro5-4864 injected i.p. inhibited the capacity of macrophages to produce interleukin-1, tumor necrosis factor and interleukin-6. Clonazepam remained ineffective. These results demonstrate an in vivo immunosuppressive property of peripheral and mixed but not central -type benzodiazepines affecting characteristic phagocyte functions involved in host-defense mechanisms as well as in inflammatory response.

Animals↗