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Biomedical subjects

S Dumont

Publications and source records attributed to S Dumont.

At least 19 recordsLinked to original sources
PubMed2001

Randomized trial of a noninvasive strategy to reduce hospital stay for patients with low-risk myocardial infarction.

OBJECTIVES: This study evaluated the feasibility, pertinence and psychosocial repercussions of a noninvasive reduced hospital stay strategy (three days) for low-risk patients with acute myocardial infarction using simple clinical criteria and predischarge 24-h ambulatory ST-segment ischemic monitoring. BACKGROUND: Previous studies evaluating shorter stays for uncomplicated myocardial infarction have been limited by retrospective or nonrandomized design and overdependence on invasive cardiac procedures. METHODS: One-hundred twenty consecutive patients admitted with an acute myocardial infarction fulfilling low-risk criteria were randomized 2:1 to a short hospital stay (80 patients) or standard stay (40 patients). Short-stay patients with no ischemia on ST-segment monitoring were discharged on day 3, returning for exercise testing a week later. All analyses were on an intention-to-treat basis. RESULTS: Forty-one percent of all screened patients with acute myocardial infarction would have been medically eligible for the short-stay strategy. Seventeen patients (21%) were not discharged early because of ischemia on ST-monitoring or angina. Median initial hospital stay was halved from 6.9 days in the standard stay to 3.5 days in the short-stay group. At six months, median total days hospitalized were 7.5 in the standard stay and 3.6 in the short-stay group (p < 0.0001). Adverse events and readmissions were low and not significantly different, and there were 25% fewer invasive cardiac procedures in the short-stay group. Psychosocial outcomes, risk factor changes and exercise test results were similar in the two groups. CONCLUSIONS: This reduced hospital stay strategy for low-risk patients with acute myocardial infarction is feasible and worthwhile, resulting in a substantial and sustained reduction in days hospitalized. It is without unfavorable psychosocial consequences, appears safe and does not increase the number of invasive cardiac procedures.

Adult↗
PubMed1999

Hard to swallow.

Explore the source record for details and available documents.

Anesthesia Recovery Period↗
PubMed1999

Radiotelemetry system for apnea study in lambs.

Neonatal apneas are being studied in the laboratory using polysomnographic recordings in lambs. Standard equipment, requiring animal restraint, disrupts sleep and prevents development of spontaneous apneas. The aim of the current work was to develop and validate a wireless recording equipment to study freely moving lambs. Firstly, a radiotelemetry equipment composed of a multichannel FM transmitter and a receiver was developed. Secondly, to test the telemetry equipment, each biopotential - [electroencephalogram (EEG), electrooculogram (EOG), electrocardiogram (ECG), electromyograms (EMGs), nasal airflow] - was recorded simultaneously by standard equipment and by telemetry (5 lambs). The results indicated an excellent concordance between signals obtained by both systems. Finally, the 8-channel telemetry prototype was tested for polysomnographic recordings (16 lambs). Results obtained confirmed the possibility of recording frequent REM sleep periods and spontaneous apneas. In conclusion, this radiotelemetry polysomnographic equipment brings new possibilities for research on neonatal apneas.

Animals↗
PubMed1999

CD14 expression by human mononuclear phagocytes is modulated by Clostridium difficile toxin B.

Toxin B, an exotoxin produced by the anaerobic Gram-positive bacteria Clostridium difficile, is responsible for pseudomembranous colitis in humans. It deeply modifies morphology of cultured cells and enhances their membrane surface area, which suggests a possible alteration of membrane receptor distribution. Since toxin B and bacterial lipopolysaccharide can act synergistically on TNF-alpha production by mononuclear phagocytes, the effect of toxin B on CD14 expression was investigated using flow cytometric analysis. It was shown that monocytes overexpressed CD14 after 5 h of treatment with toxin B. In contrast, after 24 h of treatment, the percentage of CD14 monocytes decreased, although, most frequently, the remaining positive cells expressed high levels of CD14 compared with untreated cells. Macrophages treated for 5 h with toxin B overexpressed CD14, but this effect persisted for at least 24 h. Both the percentage of positive macrophages and the mean level of CD14 per cell were increased. Thus toxin B can modulate expression of CD14 and its modulation depends on the differentiation status and maybe on the activation state, since some individual variations were observed in monocyte response to toxin.

Bacterial Proteins↗
PubMed1999

The cholecystokininB receptor is coupled to two effector pathways through pertussis toxin-sensitive and -insensitive G proteins.

Previous binding studies have suggested the existence of two affinity states for type B cholecystokinin receptors (CCK(B)R), which could correspond to different coupling states of the receptor to G proteins. To test this hypothesis, we have further investigated signal transduction pathways coupled to rat CCK(B)R stably transfected in Chinese hamster ovary cells. We show that CCK(B)R are coupled to two distinct transduction pathways involving two different G proteins, a pertussis toxin-insensitive/phospholipase C pathway leading to the production of inositol phosphate and arachidonic acid, and a pertussis toxin-sensitive/phospholipase A2 pathway leading to the release of arachidonic acid. We further demonstrate that the relative degree of activation of each effector pathway by different specific CCK(B)R agonists is the same, and that a specific CCK(B)R antagonist, RB213, can differentially antagonize the two signal transduction pathways elicited by these agonists. Taken all together, these data could be explained by the recently proposed theory assuming that the receptor can exist in a three-state model in which two active conformations corresponding to the complex formed by the receptor with two different G proteins coexist. According to this model, agonists or antagonists could recognize preferentially either conformation of the activated receptor, leading to variable behavior in a system containing a single receptor type.

Animals↗
PubMed1999

Wake up of transposable elements following Drosophila simulans worldwide colonization.

Transposable elements (TEs) make up around 10%-15% of the Drosophila melanogaster genome, but its sibling species Drosophila simulans carries only one third as many such repeat sequences. We do not, however, have an overall view of copy numbers of the various classes of TEs (long terminal repeat [LTR] retrotransposons, non-LTR retrotransposons, and transposons) in genomes of natural populations of both species. We analyzed 34 elements in individuals from various natural populations of these species. We show that D. melanogaster has higher average chromosomal insertion site numbers per genome than D. simulans for all TEs except five. The LTR retrotransposons gypsy, ZAM, and 1731 and the transposon bari-1 present similar low copy numbers in both species. The transposon hobo has a large number of insertion sites, with significantly more sites in D. simulans. High variation between populations in number of insertion sites of some elements of D. simulans suggests that these elements can invade the genome of the entire species starting from a local population. We propose that TEs in the D. simulans genome are being awakened and amplified as they had been a long time ago in D. melanogaster.

Animals↗
PubMed1999

[Rehabilitation and the socio-occupational reintegration of workers who have had a myocardial infarct: a pilot study].

OBJECTIVE: To evaluate in a pilot study some psychosocial impacts of a multidisciplinary rehabilitation program on work reintegration of postmyocardial infarction (MI) patients. PATIENTS AND METHODS: Two groups of 19 workers among public and governmental enterprises of the greater Quebec city area admitted to hospital for uncomplicated MI where recruited for the study. One group received multidisciplinary cardiac rehabilitation intervention and a structured return to work program. The second group received the usual care post-MI (no organized rehabilitation program). Over a period of 15 months, the following variables were measured patients' perception of their loss of autonomy, and loss of capacity to manage their emotions, physical work capacity and their capacity to meet work requirements. The impact of the intervention on convalescence time and patients' stability at work were also evaluated. RESULTS: The rehabilitation group showed a better development than the usual care group of capacity to manage emotions (P=0.004) and of capacity to return to work (P=0.006). Furthermore, the patients in the intervention group reintegrated their work environment following a convalescence of 84.32+/-35.39 days compared with 151.39 +/-75.53 days for the usual care patients (P=0.0007). CONCLUSION: A multidisciplinary rehabilitation program and a structured return to work program are beneficial for sociovocational reintegration of post-MI patients.

Adaptation, Psychological↗
PubMed1998

Antioxidants inhibit the in vitro production of inflammatory cytokines in Crohn's disease and ulcerative colitis.

BACKGROUND: Modulation of cytokine secretion may be of interest in the treatment of Crohn's disease or ulcerative colitis. METHODS: The effect of three antioxidants - butylated hydroxyanisol, tetrahydropapaveroline and nordihydroguaiaretic acid - on the production of tumour necrosis factor (TNF), interleukin (IL) 1, IL-6 and IL-8 (measured by enzyme-linked immunosorbent assay) by peripheral mononuclear cells and biopsies of inflamed colonic mucosa from inflammatory bowel disease patients were studied. RESULTS: We observed a decrease in IL-1 and IL-6 production by peripheral mononuclear cells from inflammatory bowel disease patients (approximately 50% of control). The three drugs did not decrease IL-6 and IL-8 secretion by colonic biopsies, whereas they did inhibit IL-1 and, to some degree, TNF production. The cytokine-inhibitory effect of antioxidants seems to be more pronounced in ulcerative colitis than in Crohn's disease. CONCLUSION: Our results suggest that the studied antioxidants, or related compounds, may be of interest in inflammatory bowel disease treatment.

Adult↗
PubMed1998

Antiproliferative properties of human alveolar macrophages.

OBJECTIVE: The aim of our study was to determine whether macrophages from lung cancer patients could acquire antitumoral properties in an in vitro model. METHODS: We isolated macrophages from bronchoalveolar lavages performed in two groups of patients: patients with lung cancer and patients with lung infection. All patients were smokers. We used the inhibition of incorporation of 3H-thymidine by U937 tumoral cells as an in vitro cytostatic assay. RESULTS: When stimulated by gamma interferon, alveolar macrophages either from lung cancer patients or from patients with lung infection induced cytostasis of proliferating U937 tumoral cells. This effect could be reproduced by using the supernatants of cultures of activated macrophages. When using optimal doses, gamma interferon showed an increased activity as compared with lipopolysaccharide. The combination of these two compounds was no more effective than gamma interferon alone in cancer patients. A macrophage/U937 tumoral cell ratio of 1/1 was sufficient to achieve a near-maximal cytostatic effect. CONCLUSIONS: Our results demonstrate that it is possible to activate, in vitro, alveolar macrophages from lung cancer patients by stimulation with gamma interferon. These macrophages acquire antiproliferative properties against a sensitive tumoral cell line.

Bronchoalveolar Lavage Fluid↗
PubMed1997

In vitro effects of oxpentifylline on inflammatory cytokine release in patients with inflammatory bowel disease.

BACKGROUND: Inflammatory cytokines, including tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1 beta, have been implicated as primary mediators of intestinal inflammation in inflammatory bowel disease. AIM: To investigate the in vitro effects of oxpentifylline (pentoxifylline; PTX; a phosphodiesterase inhibitor) on inflammatory cytokine production (1) by peripheral mononuclear cells (PBMCs) and (2) by inflamed intestinal mucosa cultures from patients with Crohn's disease and patients with ulcerative colitis. METHODS: PBMCs and mucosal biopsy specimens were cultured for 24 hours in the absence or presence of PTX (up to 100 micrograms/ml), and the secretion of TNF-alpha, IL-1 beta, IL-6, and IL-8 determined by enzyme linked immunosorbent assays (ELISAs). RESULTS: PTX inhibited the release of TNF-alpha by PBMCs from patients with inflammatory bowel disease and the secretion of TNF-alpha and IL-1 beta by organ cultures of inflamed mucosa from the same patients. Secretion of TNF-alpha by PBMCs was inhibited by about 50% at a PTX concentration of 25 micrograms/ml (IC50). PTX was equally potent in cultures from controls, patients with Crohn's disease, and those with ulcerative colitis. The concentrations of IL-6 and IL-8 were not significantly modified in PBMCs, but IL-6 increased slightly in organ culture supernatants. CONCLUSIONS: PTX or more potent related compounds may represent a new family of cytokine inhibitors, potentially interesting for treatment of inflammatory bowel disease.

Adult↗
PubMed1997

[Interleukin-8 is an important inflammatory mediator in hemorrhagic rectocolitis and Crohn disease].

OBJECTIVES: The aim of the study was to assess in vitro the production of interleukin 8 in Crohn's disease and ulcerative colitis. PATIENTS AND METHODS: Interleukin 8 concentrations (measured by ELISA) were evaluated in the culture supernatants of: a) peripheral blood mononuclear cells from 13 patients with Crohn's disease, 7 patients with ulcerative colitis and 7 controls, b) organ cultures of inflamed (22 Crohn's disease, 15 ulcerative colitis) and uninflamed (21 Crohn's disease, 9 ulcerative colitis, 15 controls) intestinal mucosal biopsies. RESULTS: In patients with Crohn's disease and ulcerative colitis, the production of interleukin 8 by peripheral blood mononuclear cells and inflamed mucosa was higher than in controls (P < 0.01) without statistical difference between Crohn's disease and ulcerative colitis. Interleukin 8 production by normal mucosa was not different between the 3 groups. Interleukin 8 concentrations in the supernatants of organ culture were positively correlated to an endoscopical and a histological inflammatory index as well as to tumor necrosis factor, interleukin 1 and 6 concentrations. CONCLUSION: These results support the notion that interleukin 8 plays an important role in the pathogenesis of inflammatory bowel disease.

Adult↗
PubMed1996

Mistletoe lectins I, II and III induce the production of cytokines by cultured human monocytes.

The three mistletoe (Viscum album L.) lectins. ML I, ML II and ML III, were tested on their ability to enhance the secretion of the cytokines tumor necrosis factor (TNF)alpha, interleukin (IL)-1 alpha, IL-1 beta and IL-6 by human monocytes obtained from healthy donors. At lectin concentrations from 0.02 to 20/pg ml (100-10,000-fold lower than those showing toxic effects), stimulations of cytokine production several-fold over control values were observed. The immunoactivating concentrations by the three lectins were found different for each donor. At toxic concentrations, the amounts of IL-1 alpha, IL-1 beta and to a less extent of TNF alpha in monocytes supernatants were particularly high. The data are discussed in relationship with the cytotoxic and immunoactivating effects of mistletoe lectins and their interest in cancer treatment.

Cells, Cultured↗
PubMed1996

Mucosal inflammatory cytokine production by intestinal biopsies in patients with ulcerative colitis and Crohn's disease.

Chronic inflammation in inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis) may be attributed partly to increased secretion of inflammatory cytokines. The aim of this study was to investigate simultaneously the spontaneous release patterns of tumor necrosis factor-alpha (TNF-alpha), interleukin-1-beta (IL-1 beta), and interleukin-6 (IL-6) by organ cultures of inflamed mucosa from IBD patients. Organ cultures of involved IBD mucosa spontaneously produced increased amounts of TNF-alpha, IL-1 beta, and IL-6 compared to normal mucosa. The patterns of cytokine release between Crohn's disease and ulcerative colitis organ cultures were not significantly different. Increased inflammatory cytokine production by lamina propria mononuclear cells (LPMCs) and mucosa treated with EDTA suggests that these cytokines originate mainly from LPMCs. These results confirm the role of inflammatory cytokines in IBD and shed a new light on the role of TNF-alpha in IBD.

Adult↗
PubMed1996

Increased production of tumour necrosis factor-alpha interleukin-1 beta, and interleukin-6 by morphologically normal intestinal biopsies from patients with Crohn's disease.

BACKGROUND: Increasing evidence points to a important role for inflammatory cytokines for the pathogenesis of Crohn's disease. AIM: To compare the secretion rate of tumour necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) by morphologically normal and inflamed intestinal mucosa from patients with Crohn's disease. RESULTS: Organ cultures of intestinal biopsy specimens taken from areas of affected mucosa from patients with Crohn's disease spontaneously produced increased amounts of TNF-alpha, IL-1 beta, and IL-6 compared with controls but also biopsy specimens taken in macroscopically and microscopically unaffected areas in the same patients. Concentrations of IL-1 beta and IL-6 measured in the supernatant fluid of biopsy cultures were positively correlated with the degree of tissue involvement measured by both endoscopic and histological grading. By contrast, TNF-alpha concentrations were not correlated to endoscopic and histological grading. CONCLUSIONS: These consistently raised TNF-alpha, IL-1 beta and IL-6 secretions by normal appearing mucosa from patients with Crohn's disease provide evidence for a sustained immune stimulation in Crohn's disease even in the absence of patent inflammation. The results shed a new light on the role of inflammatory cytokines in the onset of intestinal tissue damage in Crohn's disease and suggest that the range of intestinal lesions in Crohn's disease may be wider than suspected on the basis of regular endoscopic and histological examinations.

Adult↗
PubMed1996

In situ activation of mouse alveolar macrophages by aerosolized liposomal IFN-gamma and muramyl tripeptide.

Interferon-gamma (IFN-gamma) was entrapped with an efficiency of 30-40% in muramyl tripeptide-containing liposomes by a freeze-thawing procedure. A microcytotoxicity assay was developed to measure the tumoricidal activity of mouse alveolar macrophages (AM) against tumoral target cells with a colorimetric viability test. Free IFN-gamma and liposomal muramyl tripeptide phosphatidylethanolamine (MTP-PE) were found to be only slightly effective to activate in vitro AM, whereas encapsulation of both INF-gamma and MTP-PE within the same liposomes produced higher activation of AM. Aerosolized IFN-gamma and liposomal immunomodulators enhanced antitumor properties of AM recovered in mice 24 h postinhalation. Whereas free IFN-gamma also induced a substantial activation of peritoneal macrophages, liposomal encapsulation significantly reduced the systemic activity of inhaled immunomodulators. This approach provides a useful model for the compartmentalized organ-specific activation of AM in mice.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1996

Mycophenolic acid suppresses protein N-linked glycosylation in human monocytes and their adhesion to endothelial cells and to some substrates.

Mycophenolic acid (MPA) is the active part of the corresponding morpholinoethyl ester pro-drug Mycophenolate Mofetil. MPA, an inhibitor of IMP dehydrogenase, depletes GTP and thereby suppresses transfer of mannose and fucose to proteins. Treatment of human monocytes with a clinically attainable concentration of MPA (10 microM) decreases their attachment to endothelial cells and to laminin, but not to type I collagen or fibronectin. Our results not only elucidate a major role of mannose/fucose residues in homing of monocytes on activated endothelium but also explain in part the beneficial effects of MPA in rheumatoid arthritis and organ graft rejection.

Antigens, Surface↗