Biomedical subjects

N Seta

Publications and source records attributed to N Seta.

At least 55 records · Page 3Linked to original sources

PubMed1998

Oncostatin M is a potent stimulator of alpha1-antitrypsin secretion in lung epithelial cells: modulation by transforming growth factor-beta and interferon-gamma.

alpha1-Antitrypsin (alpha1-AT) plays a key role in lung homeostasis. Although the hepatocyte is considered as the primary source of alpha1-AT, we have previously demonstrated that rat alveolar epithelial type II cells as well as the human A549 cell line synthesize alpha1-AT, suggesting its local production within the lung. In the present study, we showed that oncostatin M, as opposed to interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), or IL-6, is a potent stimulator of alpha1-AT synthesis in the human A549 cell line. The oncostatin M-induced alpha1-AT secretion is modulated by interferon-gamma (IFN-gamma) and transforming growth factor-beta (TGF-beta) at both the protein and mRNA levels. IFN-gamma decreases oncostatin M-induced alpha1-AT secretion. By contrast, TGF-beta in combination with oncostatin M induces a dramatic and synergistic upregulation that is not observed in the HepG2 hepatocyte cell line. Our results suggest that during an inflammatory process, alveolar epithelial cells may contribute to the antiprotease defense within the lung.

Animals↗

PubMed1997

Sequential study of serum glycoprotein fucosylation in acute hepatitis.

BACKGROUND: alpha-Fetoprotein is a useful diagnostic marker in hepatocellular carcinoma, during which its serum level increases and its glycan structure is hyperfucosylated. Normally-expressed glycoproteins (alpha 1-antitrypsin and transferrin) are also hyperfucosylated in hepatocellular carcinoma. alpha-fetoprotein serum levels are also increased in conditions associated with hepatic regeneration, such as acute hepatitis. We conducted a longitudinal study of the alpha 1-6 fucosylation pattern of serum alpha-fetoprotein in ten patients with acute hepatitis and compared it to that of transferrin and alpha 1-antitrypsin. METHODS: Protein levels were measured by using immunochemical assays. Crossed affinoimmunoelectrophoresis in the presence of Lens culinaris agglutinin was performed for each protein, and the fucosylation index, corresponding to the agglutinin reactive fraction, was determined. The results were compared to those in 25 healthy donors and five newborns. RESULTS: alpha-Fetoprotein was hyperfucosylated and remained stable throughout the course of the disease. In contrast, serum transferrin and alpha 1-antitrypsin gradually became hyperfucosylated during the course of acute hepatitis. The transferrin and alpha 1-antitrypsin fucosylation indexes correlated with each other, but not with the alpha-fetoprotein fucosylation index. No correlation was found between alpha-fetoprotein, alpha 1-antitrypsin and transferrin fucosylation indexes and the corresponding glycoprotein serum levels. CONCLUSIONS: Hyperfucosylation of alpha-fetoprotein is not specific to hepatocellular carcinoma. Increased alpha 1-6 fucosylation should not be considered solely as a tumour marker, but might also reflect cell proliferation. The study of alpha 1-6 hyperfucosylation process of normally-expressed glycoproteins awaits further investigation, to test its usefulness as a new marker of liver regeneration during the follow-up of acute hepatitis.

Acute Disease↗

PubMed1997

Endothelin-1 secretion by alveolar macrophages in systemic sclerosis.

Endothelin-1 (ET-1), a potent fibroblast/smooth muscle cells mitogen, has been implicated in the pathogenesis of systemic sclerosis lung disease (SSc). Since monocytes and macrophages are thought to be activated in SSc, we hypothesized that alveolar macrophages (AM) and their precursors blood monocytes from patients with SSc produced more ET-1 than cells from healthy subjects. ET-1 and big ET-1 concentrations were measured in plasma, in bronchoalveolar lavage (BAL) fluids and in cell culture supernatants from monocytes and alveolar macrophages derived from 13 patients with definite SSc with lung involvement and from 10 control subjects. Plasma and BAL fluid ET-1 and big ET-1 levels were similar in both controls and patients with SSc. ET-1 and big ET-1 concentrations in unstimulated alveolar macrophage supernatants were similar in both groups. In contrast, LPS-stimulated alveolar macrophages from patients with SSc secreted higher amounts of ET-1 and big ET-1 than control subjects. ET-1 and big ET-1 concentrations in monocyte supernatants (either LPS-stimulated or not) were not different in patients and controls. These results show that AM from patients with SSc are hyperresponsive to LPS in vitro in terms of ET-1 and big ET-1 production and suggest that AM could participate in vivo in the overproduction of this potentially profibrotic mediator in patients with SSc.

Adolescent↗

PubMed1996

Diagnostic value of Western blotting in carbohydrate-deficient glycoprotein syndrome.

Carbohydrate-deficient glycoprotein syndrome (CDGS) is a newly recognized family of diseases characterized by the absence from the transferrin molecule of at least one glycan chain (type I) or an antenna of the glycan chain (type II). CDGS is currently diagnosed by studies of serum transferrin sialylation. We have developed an alternative Western blot-based method to detect serum transferrin species with reduced molecular masses due to altered glycosylation. Two additional bands are observed in type I CDGS, while a single lower band is observed in type II CDGS, relative to healthy subjects. N-glycanase treatment of serum from type I CDGS patients and normal subjects yields a single band of the same mass in the two cases, confirming that the glycan is the only moiety involved in the differential Western blot pattern. Similar results were found with serum alpha 1-acid glycoprotein, haptoglobin and alpha 1-antitrypsin. Western-blot analysis of one or more serum glycoproteins permits the differential diagnosis of CDGS.

Adult↗

PubMed1996

Comparison of fluconazole and amphotericin B for treatment of experimental Candida albicans endocarditis in rabbits.

Amphotericin B (AmB) and fluconazole, administered intraperitoneally for 7 days, were compared in a rabbit model for Candida albicans endocarditis. When given early, AmB was more effective than fluconazole for reducing CFU counts in vegetations (P < 0.01) and kidneys. Forty-eight hours after the last dose, AmB was still detected in all vegetations whereas fluconazole was detected in only one case.

Amphotericin B↗

PubMed1996

Compartmentalized IL-8 and elastase release within the human lung in unilateral pneumonia.

Because interleukin 8 (IL-8) is a potent neutrophil chemotactic and activating cytokine, we investigated IL-8 production in relation to neutrophil migration and elastase release in the human lung during unilateral community-acquired pneumonia (CAP). In 17 patients, the local response in the involved lung was compared with that in the contralateral, noninvolved lung, and with the systemic response. Eight healthy volunteers served as controls. IL-8, total neutrophil elastase (NE), free elastase activity, alpha 1-antitrypsin (alpha 1-AT), and total leukocyte and neutrophil counts were evaluated in bronchoalveolar lavage fluids (BALF). Mean IL-8 concentrations in BALF from the involved lungs of the patients were significantly greater than those in BALF from the noninvolved lung or from controls (p < or = 0.001). By contrast, the serum IL-8 concentration was not different in patients and in controls. Total NE and alpha 1-AT concentrations were increased in BALF from the involved lung as compared with the noninvolved lung or controls (p < or = 0.001). The elastase-inhibitory capacity of alpha 1-AT in BALF was impaired in the involved lung of seven of the 14 patients as compared with the controls, leading to free elastase activity in the involved lung of all patients with CAP. Plasma total NE concentrations were significantly greater in the CAP patients than in the controls. IL-8 concentrations in BALF correlated positively with total leukocyte counts, absolute numbers and percentages of neutrophils, total NE concentrations, and free elastase activity. Our results suggest that during unilateral CAP, locally produced IL-8 may trigger neutrophil accumulation and activation, thus contributing to a local elastase/antielastase imbalance within the site of infection.

Adolescent↗

PubMed1994

Secretion of alpha 1-antitrypsin by alveolar epithelial cells.

We have investigated the ability of alveolar epithelial cells (human A549 cell line and rat type-II pneumocytes) to produce alpha 1-antitrypsin (AAT). Northern blot analysis demonstrated the presence of an AAT-specific mRNA transcript in A549 cells. Unstimulated A549 cells secreted immunoreactive AAT at a rate of 0.51 +/- 0.04 ng/10(6) cells/h, with a modified glycosylation compared to serum AAT. AAT formed a complex with neutrophil elastase. Rat type-II pneumocytes secreted immunoreactive AAT. Our results suggest that alveolar epithelial cells could participate in antiprotease defense within the lung through local AAT production.

Amidohydrolases↗

PubMed1994

Effect of the platelet activating factor antagonist BN52021 in rabbits: role in gentamicin nephrotoxicity.

Platelet activating factor (PAF) is an ubiquitous phospholipid that acts as a mediator of numerous pathophysiological conditions, including drug nephrotoxicity. Aminoglycosides are potent antibiotics but their use is limited by their nephrotoxic potential. We assumed that PAF could participate in inducing gentamicin nephrotoxicity, and we used the PAF antagonist BN52021 to test this hypothesis. We studied renal glomerular and tubular function by clearance techniques and renal histology in four groups of New Zealand male rabbits treated for 7 days with isotonic saline, BN52021, gentamicin, or gentamicin + BN52021. BN52021 alone reduced only fractional excretions (FE) of sodium and chloride, without modifying the other parameters studied. Renal histology was not altered. Gentamicin reduced glomerular filtration rate and renal plasma flow. Free water clearance was not modified. Sodium, potassium, chloride, calcium, and magnesium FEs were raised. Renal histology showed a massive and diffuse tubular necrosis. BN52021 did not modify gentamicin glomerular, tubular, or histopathological alterations. These data suggest that PAF might physiologically affect tubular function in New Zealand male rabbits, increasing sodium and chloride excretions, and in a minute manner, potassium, calcium, and magnesium excretions. Under our experimental conditions, there was no evidence for a role of PAF in gentamicin nephrotoxicity.

Animals↗

PubMed1994

Comparison of enhanced chemiluminescence and colorimetric techniques for the immuno-detection of alpha 1-antitrypsin.

In order to detect, characterize and quantify blotted proteins, such as human alpha 1-antitrypsin (AAT), there is a need for a specific, extremely sensitive, non-radioactive and uniform revelation system applicable to diluted biological fluids and to culture supernatants of cells isolated from such fluids. We compared two immunochemical revelation systems, enhanced chemiluminescence (ECL) and colorimetric procedures, applied to human ATT, after determining their optimal conditions of performance. ECL was the most sensitive method (down to 50 pg blotted AAT), but could not be used to quantify AAT. In contrast, the colorimetric method enables quantification of blotted AAT, either simply dotted or transferred after SDS-polyacrylamide gel electrophoresis, but is not as sensitive as ECL. Using these two complementary procedures, we have been able to detect AAT in the culture supernatant of a monocytic cell line (THP-1), to characterize the different forms of AAT present in the culture supernatant of blood monocytes and to quantify both.

Cell Line↗

PubMed1994

Interleukin 6 secretion by monocytes and alveolar macrophages in systemic sclerosis with lung involvement.

Interleukin-6 (IL-6) has been involved in the pathogenesis of inflammatory and/or autoimmune diseases. We characterized the production of IL-6 by blood monocytes and alveolar macrophages (AM) in 11 patients with definite systemic sclerosis (SSc) with lung involvement and in eight normal control subjects. IL-6 levels were determined in serum, bronchoalveolar lavage (BAL) supernatants, monocytes, and AM cell culture supernatants using an ELISA kit. BAL cell analysis evidenced an alveolitis with hypercellularity and increased neutrophils and mast cells absolute counts. Serum and BAL IL-6 levels were low and similar in SSc and control groups. The monocytes of the group with SSc secreted more IL-6 than did the control group, both spontaneously (p = 0.01) and after LPS stimulation (p = 0.0007). Spontaneous secretion of IL-6 by AM tended to be higher in the SSc group than in the control group (p = 0.22). LPS-induced IL-6 secretion by AM was similar in both groups. Our study demonstrates that during SSc lung disease, spontaneous and stimulated IL-6 secretion by blood monocytes is increased, compared with secretion by healthy control subjects. By contrast, IL-6 secretion by AM is normal despite evidence of mild alveolitis.

Bronchoalveolar Lavage Fluid↗

PubMed1994

Effects of mechanical ventilation on diaphragmatic contractile properties in rats.

We measured in rats the effects of 48 h of mechanical ventilation on the weight, contractile properties, and enzymatic profile of the diaphragm, the soleus and the extensor digitorium longus (EDL) muscles. Eighteen animals were randomly divided into a mechanically ventilated (MV, n = 9) group or a control (C, n = 9) group. During the 48 h of mechanical ventilation, animals in the MV group were anesthetized with sodium thiopental and enterally fed with a gastric catheter. Group C animals were neither anesthetized nor mechanically ventilated during the 48-h experimental period, and they had access to food and water ad libitum. Muscular contractile properties were measured in vitro by analysis of force-frequency curves and twitch characteristics. The weights of the three muscles were significantly reduced in the MV group compared with those in the C group. This was accompanied in the diaphragm by a reduction in the normalized force generated for all the frequencies of stimulation, except 20 Hz, whereas twitch characteristics were not modified. The forces generated by the soleus and EDL were not significantly reduced in the MV group compared with those in the C group. Diaphragm, soleus, and EDL citrate synthase and lactate dehydrogenase activities were not significantly different in the two groups. We conclude that mechanical ventilation for 48 h in rats produces a selective force reduction in the diaphragm.

Animals↗

PubMed1994

Compartmentalized cytokine production within the human lung in unilateral pneumonia.

The in situ inflammatory response developing in the human lung during a localized bacterial infection was studied in 15 patients with unilateral community-acquired pneumonia (CAP). The local response in the involved lung was compared with that in the contralateral, noninvolved lung as well as with the systemic blood response. Eight healthy volunteers served as control subjects. Concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and interleukin-6 (IL-6) were measured by ELISA in bronchoalveolar lavage (BAL) fluids (n = 15), serum (n = 15), and alveolar macrophage and monocyte culture supernatants (n = 8). The concentrations of TNF-alpha, IL-beta and IL-6 in BAL fluid were significantly higher in the involved lung than in the paired noninvolved lung (p < or = 0.01) or in healthy subjects (p < or = 0.02, p < or = 0.01, and p < or = 0.001, respectively). Serum IL-6 concentrations were higher in patients than in control subjects, whereas IL-1 beta and TNF-alpha concentrations did not differ in the two groups. Alveolar macrophages from the involved lung spontaneously released higher concentrations of IL-1 beta, IL-6, and TNF-alpha (p < or = 0.05) than did macrophages from the noninvolved lung, which served as controls. However, macrophages were hyporesponsive in terms of cytokine production to further stimulation by lipopolysaccharide (LPS) in the noninvolved and involved lung compared with controls, whereas peripheral blood monocytes were not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Interleukin-8 and neutrophils in systemic sclerosis with lung involvement.

We investigated the mechanisms and consequences of neutrophil accumulation in the airspace in 11 patients with systemic sclerosis (SSc) and interstitial lung disease. Seven normal subjects served as controls. We measured total neutrophil elastase burden, elastase activity, and alpha-1-antitrypsin (alpha 1AT) in bronchoalveolar lavage (BAL) fluid and we evaluated the in vitro interleukin-8 (IL-8, a potent chemoattractant for neutrophils) secretion by alveolar macrophages (AM). A mild neutrophil alveolitis was observed in patients when compared with control subjects. Total BAL elastase burden was higher in patients than in control subjects and correlated positively with the percentage of neutrophils in BAL. BAL elastase activity was undetectable in control subjects, but it was detected in all patients but one (mean: 257 +/- 87 mU/L). Spontaneous IL-8 secretion by AM was higher in patients with SSc than in control subjects (518 +/- 115 versus 228 +/- 65 ng/ml, p = 0.04) and positively correlated with the percentage of neutrophils in BAL (r = 0.505). We conclude that (1) the neutrophil could participate in the pathogenesis of SSC lung disease through the release of elastase; (2) the AM could contribute to the influx of neutrophils in the alveolus through the release of IL-8.

Bronchoalveolar Lavage Fluid↗

PubMed1993

Effects of diltiazem on netilmicin-induced nephrotoxicity in rabbits.

Aminoglycoside nephrotoxicity remains a common clinical problem and is the major cause of acute toxic renal failure in hospitalized patients. In recent studies, calcium channel blockers gave controversial results in the prevention of acute ischemic or toxic renal failure. The aims of the study were (i) to describe a rabbit model of mild renal failure (50% reduction in glomerular filtration rate with a mean value of 1.78 +/- 0.46 ml/kg/min) induced by netilmicin given intramuscularly at 20 mg/kg of body weight every 8 h for 5 days, (ii) to investigate the protective effect of diltiazem given at a therapeutic dose (1 mg/kg given intramuscularly every 8 h for 5 days), and (iii) to investigate the mechanisms of this protection through evaluation of function tests, optic histology, and glomerular morphometry. Animals treated with netilmicin and diltiazem exhibited an unchanged glomerular filtration rate compared with controls (3.39 +/- 0.58 versus 3.68 +/- 0.78 ml/kg/min, respectively). This protective effect was not associated with any change in systemic or renal hemodynamics (i.e., no change in renal plasma flow) or changes in the pharmacokinetics of netilmicin, as assessed by fractional excretion and cortical uptake. Netilmicin-induced tubular toxicity was unchanged by diltiazem. Our results suggest that (i) netilmicin exhibits a toxic effect at both the glomerular and the tubular levels, (ii) diltiazem, a calcium channel blocker, when given at low therapeutic doses, is able to prevent the aminoglycoside-induced renal failure through a potential glomerular mechanism. The precise mechanisms of the protection remain to be elucidated. These results deserve clinical evaluation in high-risk patients.

Aldosterone↗

PubMed1993

Cell surface carbohydrates of rat alveolar type II cells in primary culture.

Cell surface carbohydrates have been shown to be altered during cellular differentiation. Alveolar type II (ATII) cells in culture gradually lose their differentiated phenotype. Therefore, the aim of this study was: (1) to characterize changes in terminal carbohydrates of cell surface glycoproteins of rat ATII cells cultured for 1 to 5 days on plastic, and (2) to assess the concomitant changes in sialidase and sialyltransferase activity of ATII cell homogenates. Cells were surface-labeled with potassium-[3H]-borohydride after oxidation by sodium periodate at millimolar concentrations, galactose oxidase or neuraminidase plus galactose oxidase, allowing for the specific labeling of terminal sialic acids, terminal galactose/N-acetylgalactosamine (Gal/GalNAc), or terminal an penultimate Gal/GalNAc residues, respectively. Glycoproteins were separated by SDS-PAGE. On day 1, cells were heavily coated with sialic acids, since no labeling could be introduced with galactose oxidase alone. From day 1 to day 5, we observed a selective and progressive desialylation of two glycoproteins (200 and 165 kD). At the same time, the ATII cells' sialidase activity (pH 4.2) exhibited an 8-fold increase (60.3 +/- 4.0 pmol/min/mg protein on day 1 versus 406.9 +/- 3.7 pmol/min/mg protein on day 5), whereas the sialyltransferase activity increased 2-fold (212 +/- 8 fmol/min/mg protein on day 1 versus 395 +/- 82 fmol/min/mg protein on day 5) and the supernatant sialidase activity was unchanged (2.8 +/- 0.7 pmol/min/ml on day 5). Thus, the phenotypic changes of ATII cells in primary culture are accompanied by a partial cell surface desialylation and an increase in intracellular sialidase activity.

Animals↗

PubMed1992

IL6 and acute phase plasma proteins in peritoneal fluid of women with endometriosis.

Several authors have documented signs of chronic inflammation in the pelvis of women with endometriosis. We investigated the possible involvement of interleukin 6 (IL6), an important regulator of inflammation and immunity, in minimal and mild endometriosis by measuring levels of IL6 and proteins (alpha 1-acid glycoprotein, alpha 1-antitrypsin, alpha 2-HS glycoprotein and albumin) the synthesis of which is regulated by IL6, in peritoneal fluid (PF) from infertile women with histologically confirmed endometriosis (stage I and II; n = 28) and from endometriosis-free fertile (n = 14) and infertile women (n = 13). Spontaneous and LPS-induced IL6 secretion by cultured PF macrophages from women with endometriosis (n = 12) and without endometriosis (n = 9) were also studied. No significant differences were observed in the concentrations of the four proteins studied. Immunoreactive IL6 was detected in all three groups, with no significant differences. In contrast, significantly higher levels of IL6 were released by both unstimulated (P = 0.01) and LPS-stimulated (P = 0.006) peritoneal macrophages from the women with endometriosis. We conclude that local IL6 synthesis by activated macrophages may play a role in the endometriosis process.

Acute-Phase Proteins↗

PubMed1992

Factors influencing the reaction of alpha 1-fetoprotein with concanavalin A and Lens culinaris agglutinin in crossed affinoimmunoelectrophoresis.

Concanavalin A (Con A) and lentil lectin (LCA) analysis of alpha-fetoprotein (AFP) glycosylation heterogeneity is used in a variety of clinical situations. We studied the influence of analytical conditions on the separation of AFP glycoforms by using lectin-crossed affinoimmunoelectrophoresis, regardless of the AFP concentration, which can vary over a wide range in biological fluids. We defined the optimal concentration of Con A (2 g/L) and LCA (0.35 g/L) in the first-dimension gel, together with the optimum antigen (AFP)/antibody ratio in the second-dimension gel. The presence of protein in the diluent used for AFP samples was found to change the shape of crossed affinoimmunoelectrophoresis patterns without changing the percentage composition of AFP fractions. The within-run CV was less than 4% for both lectins, and the between-run CV was less than 6.3%. The minimal quantity of AFP that provided a visible pattern with both lectins was 4 ng, corresponding to 50 microL of an 80 micrograms/L AFP sample. These technical conditions allow the cellular origin of AFP to be determined, regardless of the concentration in the sample. Typical AFP lectin patterns of secreting tumors are compared with fetal and cord serum AFP.

Amniotic Fluid↗

PubMed1991

Changes in alpha 1-acid glycoprotein serum concentrations and glycoforms in the developing human fetus.

alpha 1-Acid glycoprotein concentrations and reactivity to concanavalin A were measured in maternal and fetal serum and amniotic fluid obtained from 24 women undergoing diagnostic cordocentesis at 20 to 33 wk gestation and in 30 additional fetal sera (19 to 34 weeks gestation). Maternal alpha 1-acid glycoprotein serum levels were five to ten times higher than fetal and amniotic levels. Fetal alpha 1-acid glycoprotein levels were found to increase with advancing gestational age. Using crossed immunoaffino electrophoresis with concanavalin A, alpha 1-acid glycoprotein patterns were identical in maternal serum and amniotic fluid but totally different in fetal serum. The fetal concanavalin A pattern changed progressively during fetal life towards that of the newborn. These data confirm earlier assumptions of fetal synthesis of alpha 1-acid glycoprotein and provide normal reference values for alpha 1-acid glycoprotein in fetal serum. In addition, the specific fetal concanavalin A pattern indicates that the alpha 1-acid glycoprotein glycosylation process during fetal life differs from that in post-natal life.

Amniotic Fluid↗