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Biomedical subjects

B Duclos

Publications and source records attributed to B Duclos.

At least 55 records · Page 3Linked to original sources
PubMed1997

Association between myelodysplastic syndromes and inflammatory bowel diseases. Report of seven new cases and review of the literature.

We report seven patients with both myelodysplastic syndrome (MDS) and inflammatory bowel disease (IBD): Crohn's disease in six cases, ulcerative colitis in one case. We describe their characteristics, and those of 10 previously published similar cases are presented here. Median age at diagnosis of IBD (61 years) was high, as compared to the usual age at diagnosis of IBD. IBD was diagnosed first in nine cases, MDS first in one patient, and both diseases were diagnosed simultaneously in seven cases. Concerning IBD, there was a strong predominance of Crohn's disease (15/17 cases), with an unusually high frequency of colonic involvement (11/15 cases). MDS, in 12/17 cases, showed no excess of marrow blasts. Cytogenetic analysis was abnormal in five of the 13 evaluable cases. These observations suggest that the association between MDS and IBD may not be fortuitous in some cases, and that, in particular, patients with IBD and anemia of nonobvious origin should be evaluated for MDS. The pathogenesis of those associations, however, remains unclear.

Adult↗
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↗
PubMed1997

[Pharmacokinetic profile of high-dose doxorubicin administered during a 6 h intravenous infusion in breast cancer patients].

The purpose of our investigation was to evaluate the pharmacokinetic profile of doxorubicin administered by a new schedule. Nine non-pretreated young women with high risk breast cancer (mean age: 38, range: 29-45) entered this trial and received, cyclophosphamide (600 mg/m2) given as a 30-min infusion followed by doxorubicin (120 mg/m2) as a continuous infusion over 6 h. Chemotherapy was combined with hematopoietic factor support (G-CSF or GM-CSF). Blood was sampled over the 0-54 h period and 14 cycles were studied for pharmacokinetics. Doxorubicin as well as its major metabolite doxorubicinol were assayed in plasma specimen by high performance liquid chromatography. Mean doxorubicin plasma concentration peak was 42.6 ng/ml (standard deviation (SD): 13.3). The mean terminal half-lives were 32.6 h (SD: 22.0) and 39.2 h (SD: 21.6) for doxorubicin and doxorubicinol, respectively. Mean areas under the plasma concentration-time curve (AUC) were 413 ng/h-1 ml (SD: 103) and 1,707 ng/h-1 ml (SD: 815) for doxorubicin and doxorubicinol respectively. Consequently, the ratio of the AUC of doxorubicinol to that of doxorubicin was high (mean: 4.1 (SD: 1.6)) contrasting with previous studies reporting ratios less than 1 in patients with normal liver function. The systemic clearance of doxorubicin was 5.23 l/min/m2 (SD: 1.91). The inter- and intra-patient variability for AUC was low for both drugs. Hence the coefficients of variation were 24.6% for doxorubicin, 26.2% for doxorubicinol (inter-individual variation) and less than 10% for both compounds (intra-individual variation). In conclusion, the pharmacokinetic profile of doxorubicin (120 mg/m2) administered as a 6 h-continuous infusion is characterized by a greater exposure to doxorubicinol. This could be explained by a saturation in the biliary excretion process during the period following the end of the infusion.

Adult↗
PubMed1997

[Relationships between p53 induction, cell cycle arrest and survival of normal human fibroblasts following DNA damage].

It is now well established that in response to genotoxic stresses mammalian cells show an increased p53 protein levels and undergo cell cycle arrest at G1/S and G2/M checkpoints. But, the consequences of these cell cycle arrests on cell survival are not yet elucidated. In this study, we have analysed the relationships between p53 protein induction, cell cycle arrest and cell survival following exposure of normal human fibroblasts (NHFs) to various genotoxic agents such as cisplatin, UV radiation and gamma radiation. p53 protein accumulation and G2/M arrest arose at the same time following exposure to DNA damaging agents, suggesting that p53 is responsible for the G2/M block. However, following inhibition of p53 induction by an antisense oligonucleotide, this G2/M arrest is even more important and correlates with an enhanced sensitivity of NHFs to UV radiation. In addition, there appears to be a threshold in the response of NHFs to DNA damaging agents, p53 induction and cell cycle arrest being observed only with lethal UV doses. We show that: 1) there appears to be a threshold in the cellular response to genotoxic agents, below which neither p53 induction, nor cell cycle arrest, nor cell survival alteration occur and beyond which p53 induction is accompanied by cell cycle arrest and decreased cell survival; 2) although there is a tight temporal relationship, the onset of which depends of the DNA damaging agent used, between the start of p53 induction and the occurrence of G2/M arrest, this latter is independent of p53; 3) p53 inhibition enhances NHFs' sensitivity to DNA damaging agents, the extent of the G2/M arrest correlating with decreased cell survival. Finally, the lack of obligatory correlation between p53 inactivation, apoptosis and radio- or chemoresistance is discussed.

Apoptosis↗
PubMed1997

[Treatment with cyclosporine of severe colitis in hemorrhagic rectocolitis. Apropos of 7 cases].

Cyclosporin has been suggested as an alternative treatment in severe acute ulcerative colitis. In a retrospective study, the outcome of seven ulcerative colitis patients treated by intravenous cyclosporin (mean dose 3.6 mg/kg/day) has been evaluated. Short-term results indicated full remission in 3/7 (43%) patients. At long term follow-up (one year), only 2/7 patients could avoid ileal pouch-anal anastomosis. Two complications (one colonic perforation and one septicemia) were observed. Our results suggest that intravenous cyclosporin should not be recommended as a standard therapy in severe acute ulcerative colitis. Its use has to be limited in patients presenting a major contraindication for surgery and has to be performed by those experienced in both immunosuppressive treatment and inflammatory bowel disease.

Acute Disease↗
PubMed1996

Pyrophosphate is a source of phosphoryl groups for Escherichia coli protein phosphorylation.

Pyrophosphate can serve as a source of phosphoryl groups for the phosphorylation of E. coli proteins. The main target of such phosphorylation is a 49-kDa protein which is covalently modified at serine. The same phosphorylation pattern is obtained in the presence of ATP, which suggests that pyrophosphate can substitute for ATP for bacterial protein phosphorylation.

Autoradiography↗
PubMed1996

Autophosphorylation of a bacterial protein at tyrosine.

Autophosphorylation at tyrosine is a common process in eukaryotic kinases, which is generally modulated by regulatory ligands and affects the properties of these enzymes. We report that this type of modification occurs also in bacteria, namely in an 81 kDa protein from Acinetobacter johnsonii. This protein is phosphorylated at the expense of ATP exclusively at tyrosine residues. It is located in the inner-membrane fraction of cells and can be totally solubilized by detergents. It has been purified to homogeneity by antiphosphotyrosine immunochromatography. Analysis of the peptides released under trypsin proteolysis of the protein has shown that it autophosphorylates at several tyrosine residues. The discovery of protein autophosphorylation in bacteria seems of special interest for studying the regulatory aspects of this modification when considering the relative simplicity of the bacterial systems, as compared with most eukaryotic systems, namely in terms of physiology and genetics.

Acinetobacter↗
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

Intravenous cyclosporine in attacks of ulcerative colitis: short-term and long-term responses.

The present study reports the results of intravenous cyclosporine in 32 patients with refractory and/or severe attacks of ulcerative colitis (UC). Twenty of 32 patients responded to intravenous cyclosporine; cyclosporine was clinically effective and improved colonic lesions. However, one colonic perforation and one postoperative death were observed in two patients with severe endoscopic colitis who had failed to reach clinical remission with high-dose corticosteroids and cyclosporine. Moreover, after a median follow-up of 190 days, only one-third of the patients avoided colectomy. No predictive factor of response to cyclosporine was identified. This study confirms that cyclosporine is effective in severe UC but suggests that its use could be associated with serious complications in patients with severe lesions who had failed to settle with corticosteroids and cyclosporine.

Adolescent↗
PubMed1996

Therapeutic equivalence of single oral doses of dolasetron mesilate and multiple doses of ondansetron for the prevention of emesis after moderately emetogenic chemotherapy. European Dolasetron Comparative Study Group.

This multicentre, randomised, double-blind study was designed to compare the anti-emetic efficacy and safety of single oral doses of dolasetron mesilate with that of the approved oral, multiple-dose regimen of ondansetron in 399 cancer patients receiving moderately emetogenic chemotherapy. Single oral doses of 25, 50, 100 or 200 mg of dolasetron mesilate were administered 1 h prior to the initiation of moderately emetogenic chemotherapy. Multiple doses of ondansetron (8 mg x 3 or 8 mg x 4) capsules, or matching placebo for patients randomised to dolasetron, were given 1.5 h before and 6.5, 14.5 and 22.5 h after the start of chemotherapy (total dose = 32 mg). Efficacy was evaluated for 24 h after the initiation of chemotherapy. The most frequently used moderately emetogenic chemotherapeutic agents included cyclophosphamide, doxorubicin and carboplatin (28.4, 23.1 and 20.6% of patients, respectively). A statistically significant (P < 0.001) linear dose-response relationship was observed over the entire dolasetron dosage range for all efficacy parameters. Complete response rates were 45.0, 49.4, 60.5 and 76.3% for 25, 50, 100 and 200 mg dolasetron mesilate, respectively, and 72.3% of ondansetron patients. A single oral 200 mg dolasetron mesilate dose was therapeutically equivalent to ondansetron for all efficacy parameters and patient satisfaction was high. Overall, there were no significant differences in the incidence of adverse events between any of the dolasetron mesilate doses, or between dolasetron and ondansetron. Headache was most frequently reported (approximately 15% for each drug). No clinically important changes in vital signs or clinical laboratory parameters were observed with either drug. In conclusion, a single oral 200 mg dolasetron mesilate dose was therapeutically equivalent to multiple-dose ondansetron in the prevention of emesis and nausea following moderately emetogenic chemotherapy.

Adult↗
PubMed1996

Mesalamine in Crohn's disease with steroid-induced remission: effect on steroid withdrawal and remission maintenance, Groupe d'Etudes Thérapeutiques des Affections Inflammatoires Digestives.

BACKGROUND & AIMS: Steroid dependence and early relapse are frequent after a prednisolone-induces remission in Crohn's disease. The aim of this trial was to test whether mesalamine started at the onset of steroid tapering increases the rate of weaning from prednisolone and reduces the relapse rate after prednisolone cessation. METHODS: One hundred fifty patients with active Crohn's disease were administered oral prednisolone (1 mg.kg(-1). day(-1)) x 3-7 weeks; 129 patients went into clinical remission and were randomized to Pentasa (4 g . day(-1)) or placebo, administered until weaning and for 1 year thereafter. RESULTS: Groups were similar for clinical and biological items collected initially. Weaning failure rate was 30% and 12% in the placebo and mesalamine arms, respectively. At the end of the trial, 9 of 36 patients administered placebo and 14 of 48 administered mesalamine were in remission. Both groups had similar time to relapse curves in the postweaning year; after adjusting for risk factors (high Crohn's Disease Activity Index, white blood cell count of >9 x 10(9) /l-1 at weaning, and use of a medical treatment in the month before inclusion), Pentasa was found to be superior to placebo. CONCLUSIONS: After a prednisolone-induces remission in Crohn's disease, mesalamine facilitates steroid withdrawal and, during the postweaning year, may reduce the relapse rate in certain patient subgroups.

Adolescent↗
PubMed1996

5-Fluorouracil versus 5-fluorouracil plus alpha-interferon as treatment of metastatic colorectal carcinoma. A randomized study.

BACKGROUND: In 1989, S. Wadler reported very promising results (76% response rate) with a combination of 5-fluorouracil (5-FU) plus alpha-2a interferon (IFN) in the treatment of metastatic colorectal carcinoma (MCRC). In vitro, there are several potential explanations for synergism between the two agents. We therefore decided in 1989 to start a randomized study comparing 5-FU alone with 5-FU plus IFN. PATIENTS AND METHODS: 105 non-pretreated patients with measurable metastatic colorectal carcinoma entered into this study. The patients were randomly allocated either in arm A (n = 49) with 5-FU: 750 mg/m2 i.v. CI d1-d5 followed by 750 mg/m2 i.v. bolus once a week, or in arm B (n = 56) with 5-FU as in arm A plus IFN 9 x 10(6) IU sub-cutaneously three times a week. RESULTS: After two months of treatment we observed 1 CR and 2 PR in arm A (response rate 6.1%), 3 CR and 8 PR in arm B (response rate 19.6%), i.e., a significant difference (P = 0.05). Event-free survival was significantly higher in arm B (6 months) than in arm A (2 months) (P < 0.01), while median survival was slightly higher in arm B (12 months) than in arm A (10 months) (P < 0.05). For overall survival the difference was not significant after adjustment on center treatment and baseline Karnofsky status (P = 0.13). Toxicity was also greater in arm B. Sixteen percent of patients in arm A and 36% in arm B experienced certain grade 3-4 side effects (P < 0.05). CONCLUSION: 5-FU plus IFN is more effective than 5-FU alone in terms of response rate, event free survival but not of overall survival. 5-FU plus IFN is more toxic. As IFN has no demonstrated efficacy in MCRC as a single agent, this study suggests that IFN is acting as a 5-FU modulatory agent. The response rate observed (19.6%) is similar to the results obtained elsewhere with 5-FU plus leucovorin.

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

[Carboplatin and cyclophosphamide in stage Ic-IV ovarian carcinoma: retrospective study of 101 cases].

We report our experience of CBDCA-CPM combination chemotherapy as first line therapy in 101 ovarian cancers. The therapeutic scheme was: initial cytoreductive surgery followed by six chemotherapy cycles (CBDCA 400 mg/m2/d IV dl, CPM 600 mg/m2/d IV dl, dl = d21) and second-look laparotomy. The initial stages were four Ic, three IIa, four IIb, four IIc, 15 IIIa, 28 IIIb, 23 IIIc and 20 IV. After initial surgery, there were 39 macroscopic residual diseases superior to 2 cm, 26 macroscopic residual diseases inferior or equal to 2 cm, four microscopic diseases and no residual disease in 30 cases (unknown in two cases). The overall response rate to chemotherapy was 83% with 56% histologic complete response rate. The main toxicity was haematological with 60% of leucopenia grade III-IV, 52% of thrombopenia grade III-IV. Age at diagnosis, residual disease after first look surgery and length of CA 125 normalization were significant prognostic factors for survival in this series.

Adolescent↗