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Biomedical subjects

J Bienvenu

Publications and source records attributed to J Bienvenu.

At least 73 records · Page 4Linked to original sources
PubMed1995

Acute normovolaemic haemodilution does not reduce the inflammatory process induced by facial surgery.

The place of preoperative acute normovolaemic haemodilution (haematocrit = 28%-32%) in reducing postoperative inflammation was evaluated after facial surgery. Thirty-two patients scheduled for mandibular osteotomy were randomized to a nonhaemodiluted group or to a haemodiluted group. The degree of postoperative inflammation was evaluated: first by an x-ray technique (radiotelemetry) providing measurements of the tissue thickness (quantitation of facial oedema), and second by the measurement of four acute phase protein plasma concentrations during the first postoperative week. Throughout the study, no changes in facial oedema or in variation of acute phase proteins were detected after haemodilution. It is concluded that acute normovolaemic haemodilution has no effect on the intensity of facial oedema and the biological inflammation process after facial surgery.

Acute-Phase Proteins↗
PubMed1995

Implication of cytokines in the aggravation of malnutrition and hypercatabolism in elderly patients with severe pressure sores.

The objectives of this work were to study the production of the cytokines Interleukin 1 (IL-1), Interleukin 6 (IL-6), and tumour necrosis factor (TNF) in elderly patients with severe pressure sores and to assess their potential contribution to the aggravation of malnutrition. Nineteen bedridden patients with stage III or IV pressure sores, 12 bedridden patients free from pressure sores, but at risk of them, and 12 control patients without risk of pressure sores were studied. Nutritional status was evaluated using anthropometry, serum albumin, prealbumin, retinol-binding protein analyses, and delayed hypersensitivity skin tests. Acute-phase proteins (APP), cortisol, and cytokines blood levels together with cytokine production were measured. Nutritional status was poor in patients with sores and their APP, and IL-6 blood levels were significantly increased; IL-1 and TNF serum concentrations were not elevated in these patients. A significant difference in cortisol levels was observed between patients with stage III and IV sores. A local cytokine origin (especially IL-6, and also IL-1) was demonstrated. Thus cytokines, mainly IL-6, produced by tissue cells in damaged areas together with cortisol may aggravate malnutrition and hypercatabolism in patients with sores.

Acute-Phase Proteins↗
PubMed1995

sIL-2R levels in rheumatoid arthritis: poor correlation with clinical activity is due in part to disease duration.

The serum levels of soluble interleukin-2 receptors (sIL-2R) were measured in an attempt to determine whether they correlated with 'disease activity' in 59 patients suffering from rheumatoid arthritis. Our results indicate that serum levels of sIL-2R do not permit patients to be classified as having active or inactive disease according to standard clinical indices. A correlation between sIL-2R and disease duration could offer one explanation for the current discrepancies found in the literature.

Aged↗
PubMed1995

Production of proinflammatory cytokines and cytokines involved in the TH1/TH2 balance is modulated by pentoxifylline.

The modulation of cytokine release induced by pentoxifylline (PTX) has recently been demonstrated not to be restricted solely to tumor necrosis factor (TNF)-alpha. This prompted us to study the influence of PTX on a larger spectrum of cytokines with proinflammatory actions [TNF-alpha, interleukin-6, (IL)-6, IL-1 beta, IL-8] or with implied actions in the TH1 (IL-2, IFN-gamma)/TH2 (IL-10) balance. The IL-1RA was also explored. This work was performed using a whole-blood model in which cytokine production is measured after stimulation by lipopolysaccharide (LPS) (25 micrograms/ml) and phytohemagglutinin (PHA) (5 micrograms/ml) in 1:10 diluted whole blood. The stimulation test was performed in blood from healthy controls and from septic patients (without septic shock) in the presence or absence of PTX at 10(-6), 10(-5), 10(-4), or 10(-3) M. In controls and septic patients, at a 10(-4) M PTX concentration the production of IL-2 is strongly diminished (26-32% of the basal level), followed by diminution of IFN-gamma (30-40%). As expected, of the proinflammatory cytokines TNF was the most strongly suppressed (50% of baseline) followed by IL-1 (about 80% of basal production). Finally, IL-10 was also influenced by PTX (65% of baseline). At 10(-4) M, IL-1RA and IL-6 were unaffected by PTX. Taken altogether, our data demonstrate that PTX possesses a much broader spectrum of activity on cytokine production than was initially described, and it appears to be a potential and promising immunotherapeutic agent.

Adult↗
PubMed1995

Leukocyte activation study during occlusive arterial disease of the lower limb: effect of pentoxifylline infusion.

Granulocytes play a significant role in vascular diseases. The mechanisms of neutrophil-mediated vascular injury include their increased endothelial adhesion and activation with release of inflammatory mediators. Pentoxifylline (PTX) has a well-demonstrated ability to act on the activated neutrophils. It increases chemotaxis and decreases their adherence to endothelial cells, oxidative burst, and enzyme release. In this preliminary study, we investigated the effects of PTX on ischemia-induced changes in polymorphonuclear neutrophils (PMN) activation and cytokine release. A double-blind, randomized, placebo-controlled trial was carried out in 14 patients (age range 46-86 years) suffering from critical ischemia, as defined by the European Consensus Document, or subacute ischemia due to occlusive arterial disease of the lower limb. Femoral and antecubital venous blood samples on the side of the ischemic leg were obtained from patients immediately before (TO) and after infusion (T24) of PTX or placebo. PMN activation was evaluated by study of cell migration, beta 2 integrin expression (CD11b/ CD18), oxidative burst, and elastase release. Inflammation proteins were analyzed, such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-6 (IL-6), C-reactive protein (CRP), and fibrinogen. Before treatment, our results demonstrate an important activation in both femoral and antecubital venous blood. PMN activation markers, cytokine release, and other inflammation proteins were significantly increased compared with normal subjects. In the experimental group there was no significant difference between femoral and antecubital venous blood. Six patients received PTX infusion and seven patients were in the placebo group. The effect of PTX was evaluated after 24 h of treatment (1,200 mg). In the PTX group the following variables were improved compared with the placebo group: CD11b expression on PMNs, elastase released from PMNs, fibrinogen, CRP, TNF-alpha, and IL6 in plasma. These preliminary results should be interpreted with caution because of the small sample size. Further trials may contribute to more complete understanding.

Aged↗
PubMed1995

IL-3 increases marrow and peripheral erythroid precursors in chronic pure red cell aplasia presenting in childhood.

In most patients with Diamond-Blackfan anaemia (DBA) the addition of IL-3 to in vitro cultures increases the number of erythroid progenitors. However, a small proportion of patients show an erythroid response to in vivo administration of IL-3. We treated two adult patients with corticosteroid-refractory DBA, who had shown a clear in vitro erythroid response to IL-3, with increasing doses of IL-3 (from 2.5 to 10 micrograms/kg/d) by subcutaneous injections for 7 and 9 weeks. Monitoring of marrow and circulating progenitors showed a sustained elevation of BFU-E and CFU-E as well as an increase of other progenitors and CD34+ cells during therapy. However, this effect did not translate into a clear clinical response, although transfusion requirements decreased transiently in one patient. This report shows that a sustained elevation of erythroid progenitors induced by in vivo IL-3 administration may not translate into an increase of mature red cells production in DBA patients.

Adult↗
PubMed1995

[Methods for studying cytokines in biological media].

Accurate and sensitive methods for the measurement of cytokines in biological fluids are an absolute prerequisite for a proper use of these mediators in clinical practice. The authors describe the numerous molecular forms under which cytokines can possibly circulate. The potential influence of inhibitors (autoantibodies, soluble receptors) on cytokine assays is discussed. Blood collection for cytokines needs a particular attention to prevent a possible contamination by endotoxins which can trigger cytokines cellular production after sampling. If bioassays historically preceded immunoassays, these last techniques are now very popular, but there is an urgent need for standardisation between the different kits commercially available. In addition, in situ detection of cytokines using molecular biology is an helpful complementary technique to the measurement of circulating cytokines.

Artifacts↗
PubMed1995

[Exploration of cytokines in inflammation in biological fluids].

Accurate and sensitive methods for the measurement of acute phase cytokines (IL-1, IL-6, IL-8, TNF alpha, LIF) in biological fluids are an absolute prerequisite for a proper use of these mediators in clinical practice. Nowadays, numerous kits are commercially available for cytokines quantitation, but one must be very aware of the difficulties in the study of these molecules. The authors describe the various molecular forms under which cytokines can possibly circulate. The potential influence of inhibitors (autoantibodies, soluble receptors) on cytokine assays is discussed. Blood collection for cytokines needs a particular attention to prevent a possible contamination by endotoxins which can trigger cytokines cellular production after sampling. If bioassays historically preceded immunoassays, these last techniques are now very popular, but there is an urgent need for standardisation between the different kits commercially available. In addition, the study of the ability of cells to produce cytokines and the in situ detection of cytokines using molecular biology constitute helpful complementary techniques to the measurement of circulating cytokines.

Biological Assay↗
PubMed1995

[1995: a decisive progress for the interlaboratory transferability of results by using enzyme and protein reference materials].

Transferability of results in clinical enzymology and immunochemistry may be improved by using validated calibrators. For that purpose, certified reference materials (CRM) have been developed. Authors emphasize the need to make known and to use these tools properly, and on the potential efficiency of this approach in immunochemistry with CRM 470, certified for 14 plasma proteins and with enzyme CRMs produced at the international level. They recall the necessity to validate calibrators for specified techniques of measurement used in routine. They also indicate that this approach, if properly conducted, should allow to ensure the transferability of results in enzymology and immunochemistry and thus the clinical efficiency of laboratory results.

Enzymes↗
PubMed1995

[Reference material (CRM 470) for serum proteins: preparation, characteristics and conditions of use].

Several national and international quality assurance schemes clearly demonstrated the discrepancies between the results given by different analytical systems designed for the immunochemical measurement of proteins. Thus, the need for the preparation of a new international secondary reference material appeared urgent to the International Federation for Clinical Chemistry (IFCC). In this paper, the authors describe the different steps of the preparation of the new standard CRM 470. This work financed by the Bureau Communautaire de Référence (BCR) has been done in collaboration with the College of American Pathologists (CAP). The physicochemical properties of the proteins present in the CRM 470 and the various controls undertaken on the preparation are described. The CRM 470 material (40,000 lyophylised 1 ml vials) is now certified for the 14 plasma proteins of major interest in clinical chemistry. The worldwide introduction of this material will considerably improve the accuracy of immunochemical proteins' determination and will allow the determination of the reference values as a function of age and sex.

Blood Proteins↗
PubMed1994

Inhibition of immune cell proliferation and cytokine production by lipoprotein-bound gangliosides.

We have analyzed the immunomodulatory effect of human melanoma gangliosides bound to serum lipoprotein fractions on normal human immune-competent cells in vitro. Total melanoma gangliosides in micelles inhibited proliferation of peripheral blood mononuclear cells stimulated by various mitogens, modulated lymphocyte surface molecules CD2, CD3, CD4, CD5 and CD8 and inhibited the production of interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha) and IL-6 by stimulated adherent cells. Most of these effects were abrogated in the presence of serum. Purified serum lipoprotein fractions were tested for their ability to allow or inhibit the immunomodulatory effects of gangliosides. Melanoma gangliosides bound to very-low-density lipoproteins (VLDL) were shown to be as potent modulators of the immune response in vitro as when they were presented to cells in the form of micelles. Gangliosides bound to low-density lipoproteins were less active and gangliosides bound to high-density lipoproteins or the lipoprotein-free fraction had no immunomodulatory effects. Given the fact that gangliosides are predominantly bound to lipoproteins in serum, we conclude that lipoproteins are important determinants of the immunomodulating potential of tumor gangliosides, and that the immunomodulatory effects of melanoma gangliosides observed in vitro may also occur in vivo.

Antigens, CD↗
PubMed1994

Regional chemotherapy (with mitomycin C) and intra-operative hyperthermia for digestive cancers with peritoneal carcinomatosis.

Intraperitoneal chemo-hyperthermia with mitomycin C was used to treat 28 patients with far advanced digestive adenocarcinoma and histologically confirmed peritoneal carcinomatosis. Surgical resection of the primary tumor was possible in 17 cases. After closure of the abdominal wall, intraperitoneal chemo-hyperthermia was performed for 90 to 120 minutes under general anesthesia and 32 degrees C hypothermia, through 3 intraperitoneal drains forming a closed circuit, using 10 mg/l of mitomycin C in 6 liters of peritoneal dialysate heated to an inflow temperature of 46-49 degrees C. No mortality occurred, and there were 2 post-operative complications, with transitory biological side effects. In 9 out of 10 patients with preoperative malignant ascites, the ascites cleared after treatment. One-year survival rate was 54.2%. These encouraging preliminary results show that intraperitoneal chemohyperthermia with mitomycin C is a safe and reliable treatment for peritoneal carcinomatosis in far advanced digestive cancers.

Adenocarcinoma↗
PubMed1994

New international reference preparation for proteins in human serum (RPPHS).

Quality-control surveys in recent years, in various parts of the world, have shown poor between-laboratory agreement for measurements of plasma proteins. Despite the existence of international reference materials distributed by the World Health Organization, standards produced by diagnostics manufacturers and professional organizations differ significantly in their ascribed values. The reasons for this are complex but include poor availability of the primary materials, confusion about their use, and the fact that their turbidity on reconstitution precludes their use in modern optical immunoassays. This unfortunate situation led to an important initiative to produce sufficient quantities of a widely available, optically clear secondary reference material for plasma proteins that could be used worldwide by manufacturers, professional organizations, and laboratories. Here we present an overview on how the laboratory community, including manufacturers, clinical laboratories, professional societies, and regulators, has reached what we consider is a successful conclusion to a difficult problem.

Blood Proteins↗
PubMed1993

Is there a relationship between malnutrition, inflammation, and post-vaccinal antibody response to influenza viruses in the elderly?

This study was designed to explore the relationship between malnutrition, inflammation, and the specific antibody response after influenza vaccination in the elderly. Eighty-two aged subjects, immunized annually against influenza with a trivalent inactivated vaccine, were evaluated for 9 protein markers (albumin, thyroxin-binding prealbumin, transferrin, immunoglobulins (Ig) G, M, and A, orosomucoid, haptoglobin, and C reactive protein) and for their antibody response to influenza viruses in comparison to 29 younger adults who received the same vaccine and 21 unvaccinated adults. IgM and nutritional markers were significantly reduced in the aged as compared to controls, while the opposite pattern was seen for IgA and inflammatory markers. No difference was observed between the elderly and the controls with regard to the antibody response to influenza virus after vaccination. Reciprocally, influenza immunization had no influence on the levels of the protein variables. These results suggest that the protein status does not play an important role in the antibody response to influenza vaccination in the elderly, a fact which could be related to the slight involvement of cellular immunity in the defense against influenza reinfection.

Adult↗
PubMed1993

[Cancers of the stomach and peritoneal carcinoses: will hyperthermia be a new therapeutic approach?].

Overall survival rate of gastric adenocarcinoma is poor whatever the therapeutic is. Main reasons for this poor prognosis are regional failure and local recurrences. Using hyperthermia could be of interest in peritoneal carcinomatosis during gastric carcinoma: in vitro cytotoxic effect of hyperthermia is well known. Using hyperthermia in combination with intra peritoneal chemotherapy could improve local control. Preliminary results of pilot studies treating peritoneal carcinomatosis with intra peritoneal chemohyperthermia are reported.

Antineoplastic Agents↗
PubMed1992

Treatment of malignant peritoneal effusion in digestive and ovarian cancer.

Intra Peritoneal Chemo Hyperthermia (IPCH) with Mitomycin C (MMC) or Cisplatinum (CP) was used to treat 32 patients with far advanced digestive or ovarian cancers and peritoneal carcinomatosis. Surgical resection of the primary tumor has been possible in 18 cases. After closure of the abdominal wall, a 90 minutes IPCH as performed under general anaesthesia and 32 degrees C general hypothermia, through 3 intraperitoneal drainages realizing a closed circuit, using 10 mg/l of MMC or 15 to 25 mg/l of CP in 6 l of peritoneal dialysate heated at the inflow temperature of 46 to 49 degrees C. The mortality rate was 3% and the morbidity rate was 3%. In 11 out of 12 patients with preoperative malignant ascites, no more ascites could be found after IPCH. For peritoneal carcinomatosis from digestive origin, median survival was 11.2 months and 1 year survival rate was 46.9%. These encouraging preliminary results show that IPCH is a safe and reliable treatment for peritoneal carcinomatosis in far advanced digestive or ovarian cancers.

Adenocarcinoma↗
PubMed1992

Study of pentoxifylline induced modulation of TNF alpha and interleukin-6 secretion in healthy and septic patients by the use of an ex-vivo model on whole blood.

The aim of this work is to reinvestigate the pentoxifylline (PTX) action on TNF alpha and IL-6 production using a whole blood ex-vivo model. 5 healthy controls, 2 septic patients (4 samples) and 3 patients in septic shock (7 samples) have been studied. Our data confirm the inhibitory action of PTX on TNF alpha production in healthy controls. This inhibition is nearly complete for a PTX concentration of 10(-3) M. More surprisingly a suppressive activity of PTX on IL-6 secretion has been found both in controls and septic patients. On the 7 samples of the 3 patients with septic shock no TNF alpha production has been detected. Taken altogether, these observations suggest a potential role for PTX as a modulator of the major cytokines involved in the pathogenesis of septic shock.

Blood↗