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Biomedical subjects

E Teissier

Publications and source records attributed to E Teissier.

At least 19 recordsLinked to original sources

Dose-dense adjuvant chemotherapy in node-positive breast cancer: docetaxel followed by epirubicin/cyclophosphamide (T/EC), or the reverse sequence (EC/T), every 2 weeks, versus docetaxel, epirubicin and cyclophosphamide (TEC) every 3 weeks. AERO B03 randomized phase II study.

BACKGROUND: Adding a taxane to anthracycline-based adjuvant chemotherapy prolongs survival in node-positive patients but optimal dose and schedule remain undetermined. This study aimed to select a dose-dense regimen for further assessment in phase III studies. PATIENTS AND METHODS: Ninety-nine patients with node-positive invasive breast adenocarcinoma were randomly assigned to docetaxel (Taxotere) (T) 75 mg/m2, epirubicin (E) 75 mg/m2 and cyclophosphamide (C) 500 mg/m2 (TEC)x6, every 3 weeks; E 100 mg/m2, C 600 mg/m2 x 4, then T 100 mg/m2 x 4 (EC-->T) or the reverse sequence (T-->EC), every 2 weeks, with pegfilgrastim support. The primary end point was the incidence of grade 4 toxicity. RESULTS: Dose intensity was almost doubled with dose-dense regimens, compared with TEC. Twenty-seven patients experienced grade 4 toxicity: 26%, 40% and 18% with TEC, EC-->T and T-->EC, respectively, mainly neutropenia, but febrile neutropenia occurred only in 11%, 10% and 3%. Grade 3-4 nail disorders, hand-foot syndrome and peripheral neuropathy occurred in 46%, 73% and 68% of patients with TEC, EC-->T and T-->EC, respectively. CONCLUSIONS: Dose-dense regimens yield more frequent and severe nonhematological toxic effects than standard dose TEC regimen. Though grade 4 toxicity rates appear acceptable with the T-->EC regimen, the incidence of grade 3-4 events makes it difficult to recommend either dose-dense regimen for further investigation.

Adult↗

The transcriptional regulating protein of 132 kDa (TReP-132) differentially influences steroidogenic pathways in human adrenal NCI-H295 cells.

Steroid hormones synthesized from cholesterol in the adrenal gland are important regulators of many physiological processes. It is now well documented that the expression of many genes required for steroid biosynthesis is dependent on the coordinated expression of the nuclear receptor steroidogenic factor-1 (SF-1). However, transcriptional mechanisms underlying the species-specific, developmentally programmed and hormone-dependent modulation of the adrenal steroid pathways remain to be elucidated. Recently, we demonstrated that the transcriptional regulating protein of 132 kDa (TReP-132) acts as a coactivator of SF-1 to regulate human P450scc gene transcription in human adrenal NCI-H295 cells. The present study shows that overexpression of TReP-132 increases the level of active steroids produced in NCI-H295 cells. The conversion of pregnenolone to downstream steroids following TReP-132 expression showed increased levels of glucocorticoids, C(19) steroids and estrogens. Correlating with these data, TReP-132 increases P450c17 activities via the induction of transcript levels and promoter activity of the P450c17 gene, an effect that is enhanced in the presence of cAMP or SF-1. In addition, P450aro activity and mRNA levels are highly induced by TReP-132, whereas 3beta-hydroxysteroid dehydrogenase type II and P450c11aldo transcript levels are only slightly modulated. Taken together, these results demonstrate that TReP-132 is a trans-acting factor of genes involved in adrenal glucocorticoid, C(19) steroid and estrogen production.

3-Hydroxysteroid Dehydrogenases↗

Hawthorn extracts inhibit LDL oxidation.

Polyphenol-rich diet decreases cardiovascular risk. LDL oxidation is the primary event in atherosclerosis plaque formation and antioxidants such as polyphenols were shown to inhibit LDL oxidation and atherosclerosis development. Hawthorn (Crataegus) and derived pharmaceuticals are rich in polyphenols and already prescribed to treat moderate heart failure, nervousness and sleep disorders. Extracts either from fresh plant parts (flower buds, flowers, young leaves or green fruits) or from dried pharmaceutical parts (flowers and flowering tops) were previously shown to be effective inhibitors of lipoperoxidation and scavengers of oxygen species. In this study, the capacity of total and ethyl-acetate extracts from dried pharmaceutical flowers, tops and fruits to inhibit Cu(2+)-induced LDL oxidation was tested. This capacity was positively linked to their content in total polyphenols, proanthocyanidins (global and oligomeric forms), as well as to their content in two individual phenolics: a flavanol, the dimeric procyanidin B2 and a flavonol glycoside, hyperoside. Flavanol-type phenolics showed to be higher active than the majority of the flavonoids tested in inhibiting Cu(2+)-induced LDL peroxidation. This study suggests that hawthorn could be a source of polyphenols able to inhibit LDL oxidation.

Acetates↗

Peroxisome proliferator-activated receptor (PPAR) agonists decrease lipoprotein lipase secretion and glycated LDL uptake by human macrophages.

Lipoprotein lipase (LPL) acts independently of its function as triglyceride hydrolase by stimulating macrophage binding and uptake of native, oxidized and glycated LDL. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors expressed in monocyte/macrophages, where they control cholesterol homeostasis. Here we study the role of PPARs in the regulation of LPL expression and activity in human monocytes and macrophages. Incubation of human monocytes or macrophages with PPARalpha or PPARgamma ligands increases LPL mRNA and intracellular protein levels. By contrast, PPAR activators decrease secreted LPL mass and enzyme activity in differentiated macrophages. These actions of PPAR activators are associated with a reduced uptake of glycated LDL and could influence atherosclerosis development associated with diabetes.

Biological Transport↗

Role of the parasite-derived prostaglandin D2 in the inhibition of epidermal Langerhans cell migration during schistosomiasis infection.

Epidermal Langerhans cells (LCs) play a key role in immune defense mechanisms and in numerous immunological disorders. In this report, we show that percutaneous infection of C57BL/6 mice with the helminth parasite Schistosoma mansoni leads to the activation of LCs but, surprisingly, to their retention in the epidermis. Moreover, using an experimental model of LC migration induced by tumor necrosis factor (TNF)-alpha, we show that parasites transiently impair the departure of LCs from the epidermis and their subsequent accumulation as dendritic cells in the draining lymph nodes. The inhibitory effect is mediated by soluble lipophilic factors released by the parasites and not by host-derived antiinflammatory cytokines, such as interleukin-10. We find that prostaglandin (PG)D2, but not the other major eicosanoids produced by the parasites, specifically impedes the TNF-alpha-triggered migration of LCs through the adenylate cyclase-coupled PGD2 receptor (DP receptor). Moreover, the potent DP receptor antagonist BW A868C restores LC migration in infected mice. Finally, in a model of contact allergen-induced LC migration, we show that activation of the DP receptor not only inhibits LC emigration but also dramatically reduces the contact hypersensitivity responses after challenge. Taken together, we propose that the inhibition of LC migration could represent an additional stratagem for the schistosomes to escape the host immune system and that PGD2 may play a key role in the control of cutaneous immune responses.

Animals↗

Di-tert-butylhydroxylated flavonoids protect endothelial cells against oxidized LDL-induced cytotoxicity.

The protective effect of di-tert-butylhydroxylated flavonoids (chalcones and arylidenes) against minimally oxidized LDL (mO-LDL)-induced cytotoxicity was studied in cultured bovine aortic endothelial cells. Most of the tested compounds decreased aldehydes formation in medium containing mO-LDL, but their capacity to inhibit LDL oxidation in the cellular medium was not sufficient to totally reduce the cellular toxicity of mO-LDL. Most of the tested flavonoids improved the integrity of cells exposed to mO-LDL, whereas butylated hydroxytoluene was ineffective and quercetin worsened the toxicity of mO-LDL. Moreover these flavonoids induced an increase in GSH cellular levels and their protective effects might be because of their inability to reduce metal ion. Arylidene 6 substituted at position 7 by a hydroxyl group was the most potent compound.

Adenosine Triphosphate↗

Breast cancer occurred after treatment for Hodgkin's disease: analysis of 133 cases.

PURPOSE: To assess the clinical and histological characteristics of breast cancer (BC) occurring after Hodgkin's disease (HD) and give possible therapies and prevention methods. MATERIALS AND METHODS: In a retrospective multicentric analysis, 117 women and two men treated for HD subsequently developed 133 BCs. The median age at diagnosis of HD was 24 years. The HD stages were stage I in 25 cases (21%), stage II in 70 cases (59%), stage III in 13 cases (11%), stage IV in six cases (5%) and not specified in five cases (4%). Radiotherapy (RT) was used alone in 74 patients (63%) and combined modalities with chemotherapy (CT) was used in 43 patients (37%). RESULTS: BC occurred after a median interval of 16 years. TNM classification (UICC, 1978) showed 15 T0 (11.3%), 44 T1 (33.1%), 36 T2 (27.1%), nine T3 (6.7%), 15 T4 (11.3%) and 14 Tx (10.5%). Ductal infiltrating carcinoma and ductal carcinoma in situ (DCIS) represented 81.2 and 11.3% of the cases, respectively. Among the infiltrating carcinoma, the axillary involvement rate was 50%. Seventy-four tumours were treated by mastectomy without (67) or with (ten) RT. Forty-four tumours had lumpectomy without (12) or with (32) RT. Another four received RT alone, and one CT alone. Sixteen patients (12%) developed isolated local recurrence. Thirty-nine patients (31.7%) developed metastases and 34 died; 38 are in complete remission whereas five died of intercurrent disease. The 5-year disease-specific survival rate was 65.1%. The 5-year disease-specific survival rates for the pN0, pN1-3 and pN>3 groups were 91, 66 and 15%, respectively (P<0.0001), and 100, 88, and 64% for the TIS, T1 and T2. For the T3 and T4, the survival rates decreased sharply to 32 and 23%, respectively. These secondary BC are of two types: a large number of aggressive tumours with a very unfavourable prognosis (especially in the case of pN>3 and/or T3T4), and many tumours with a 'slow spreading' such as DCIS and microinvasive lesions. These lesions developed especially in patients treated exclusively by RT. CONCLUSIONS: The young women and girls treated for HD should be carefully monitored in the long-term by clinical examination, mammography and ultrasonography. We suggest that a baseline mammography is performed 5-8 years after supradiaphragmatic irradiation (complete mantle or involved field) in patients who were treated before 30 years of age. Subsequent mammographies should be performed every 2 years or each year, depending on the characteristics of the breast tissue (e.g. density) and especially in the case of an association with other BC risk factors. This screening seems of importance due to excellent prognosis in our T(1S)T(1) groups, and the possibility of offering these young women a conservative treatment.

Adolescent↗

PPAR-alpha and PPAR-gamma activators induce cholesterol removal from human macrophage foam cells through stimulation of the ABCA1 pathway.

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that regulate lipid and glucose metabolism and cellular differentiation. PPAR-alpha and PPAR-gamma are both expressed in human macrophages where they exert anti-inflammatory effects. The activation of PPAR-alpha may promote foam-cell formation by inducing expression of the macrophage scavenger receptor CD36. This prompted us to investigate the influence of different PPAR-activators on cholesterol metabolism and foam-cell formation of human primary and THP-1 macrophages. Here we show that PPAR-alpha and PPAR-gamma activators do not influence acetylated low density lipoprotein-induced foam-cell formation of human macrophages. In contrast, PPAR-alpha and PPAR-gamma activators induce the expression of the gene encoding ABCA1, a transporter that controls apoAI-mediated cholesterol efflux from macrophages. These effects are likely due to enhanced expression of liver-x-receptor alpha, an oxysterol-activated nuclear receptor which induces ABCA1-promoter transcription. Moreover, PPAR-alpha and PPAR-gamma activators increase apoAI-induced cholesterol efflux from normal macrophages. In contrast, PPAR-alpha or PPAR-gamma activation does not influence cholesterol efflux from macrophages isolated from patients with Tangier disease, which is due to a genetic defect in ABCA1. Here we identify a regulatory role for PPAR-alpha and PPAR-gamma in the first steps of the reverse-cholesterol-transport pathway through the activation of ABCA1-mediated cholesterol efflux in human macrophages.

ATP Binding Cassette Transporter 1↗

Antioxidant properties of di-tert-butylhydroxylated flavonoids.

Epidemiological evidence suggests an inverse relationship between dietary intake of flavonoids and cardiovascular risk. The biological activities of flavonoids are related to their antioxidative effects, but they also can be mutagenic, due to the prooxidant activity of the catechol pattern. To prevent these problems, we synthesized new flavonoids where one or two di-tert-butylhydroxyphenyl (DBHP) groups replaced catechol moiety at position 2 of the benzopyrane heterocycle. Two DBHP moieties can also be arranged in an arylidene structure or one DBHP fixed on a chalcone structure. Position 7 on the flavone and arylidene or position 4 on the chalcone was substituted by H, OCH(3), or OH. New structures were compared with quercetin and BHT in an LDL oxidation system induced by Cu(II) ions. Arylidenes and chalcones had the best activities (ED(50) = 0.86 and 0.21) compared with vitamin E, BHT, and quercetin (ED(50) = 10.0, 7. 4, and 2.3 microM). Activity towards stable free radical 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) was measured by log Z and ECR(50) parameters. Synthesized flavones proved to be poor DPPH radical scavengers, the activity increasing with the number of DBHP units. In contrast, arylidenes and chalcones were stronger DPPH radical scavengers (log Z > 3, 0.3 < ECR(50) < 2.12) than BHT (log Z = 0.75, ECR(50) = 12.56) or quercetin (log Z = 2.76, ECR(50) = 0.43). Unlike quercetin, synthesized compounds neither chelated nor reduced copper, proving that these new flavonoids had no prooxidant activity in vitro.

Amidines↗

Oxidized phospholipids activate PPARalpha in a phospholipase A2-dependent manner.

The peroxisome proliferator-activated receptor alpha (PPARalpha) is a transcription factor belonging to the PPAR subfamily of nuclear receptors. Fatty acids and eicosanoids are natural PPARalpha ligands. Here, we show using transient transfection assays that oxidized (oxLDL) but not native low-density lipoproteins (LDL) dose-dependently activate PPARalpha in endothelial cells without affecting PPARalpha protein expression. Fractioning of oxLDL lipids followed by transactivation experiments demonstrated that the oxidized phospholipid component in oxLDL is responsible for PPARalpha activation. Using specific inhibitors, it is shown that oxLDL-mediated PPARalpha activation requires phospholipase A2 activity and that the oxidized fatty acids 9- and 13-HODE activate PPARalpha directly. Finally, we found that, similar to the synthetic PPARalpha ligand Wy-14643, oxLDL induced expression of the fatty acid transport protein-1 in human primary endothelial cells. Our findings define a novel group of PPARalpha activators and provide a molecular basis for certain effects of these biologically active phospholipids on gene transcription.

Carrier Proteins↗

Phenylpropanoids from Ballota nigra L. inhibit in vitro LDL peroxidation.

From the European plant Ballota nigra L. various polyphenols including phenylpropanoid derivatives were isolated. There is increasing evidence that oxidized low-density lipoproteins (Ox-LDL) might be involved in the pathogenesis of atherosclerosis and it has been reported that polyphenols inhibit LDL peroxidation and atherogenesis. The goal of this study was to test whether the major polyphenolic compounds extracted from Ballota nigra, four phenylpropanoid glycosides, verbascoside, forsythoside B, arenarioside, and ballotetroside and one non-glycosidic phenylpropanoid, caffeoyl-L-malic acid, inhibit Cu(2+)-induced LDL peroxidation. The effectiveness of these compounds was compared to the activity of quercetin, a well-known polyphenol inhibitor of Cu(2+)-induced LDL oxidation. Antioxidant efficacious doses (ED 50) of arenarioside and ballotetroside were 1.8 microM and 7.5 microM respectively, while in the same conditions, the ED 50 of forsythoside B and verbascoside were similar (1 microM) and those of quercetin and of caffeoyl-L-malic acid were 2.3 microM and 9.5 microM respectively. Spectrophotometric studies show that quercetin is a Cu(2+) chelator while phenylpropanoid glycosides and caffeoyl-L-malic acid are not Cu(2+) chelators. Therefore, phenylpropanoid glycosides are strong inhibitors of Cu(2+)-induced LDL oxidation, independent of any capacity to act as Cu(2+) chelators.

Caffeic Acids↗

Application of an original RT-PCR-ELISA multiplex assay for MDR1 and MRP, along with p53 determination in node-positive breast cancer patients.

The long-term prognostic value of tumoural MDR1 and MRP, along with p53 and other classical parameters, was analysed on 85 node-positive breast cancer patients receiving anthracycline-based adjuvant therapy. All patients underwent tumour resection plus irradiation and adjuvant chemotherapy (the majority receiving fluorouracil-epirubicin-cyclophosphamide). Median follow-up for the 54 alive patients was 7.8 years. Mean age was 53.7 years (range 28-79) and 54 patients were post-menopausal. MDR1 and MRP expression were quantified according to an original reverse transcription polymerase chain reaction multiplex assay with colourimetric enzyme-linked immunosorbent assay detection (beta2-microglobulin as control). P53 protein was analysed using an immunoluminometric assay (Sangtec). MDR1 expression varied within an 11-fold range (mean 94, median 83), MRP within a 45-fold range (mean 315, median 242) and p53 protein from the limit of detection (0.002 ng mg(-1)) up to 35.71 ng mg(-1) (mean 1.18, median 0.13 ng mg(-1)). P53 protein was significantly higher in oestrogen receptor (ER)-negative than in ER-positive tumours (P = 0.039). The higher the p53, the lower the MDR1 expression (P = 0.015, r= -0.27). P53 was not linked to progesterone receptor (PR) status, S phase fraction, or MRP Significantly greater MDR1 expression was observed in grade I tumours (P = 0.029). No relationship was observed between MDR1 and MRP. Neither MDR1 nor MRP was linked to ER or PR status. Unlike MDR1, MRP was correlated with the S phase: the greater the MRP, the lower the S phase (P = 0.006, r = -0.42). Univariate Cox analyses revealed that MDR1, MRP, p53 and S phase had no significant influence on progression-free or specific survival. A tendency suggested that the greater the p53, the shorter the progression-free survival (P = 0.076 as continuous and 0.069 as dichotomous).

ATP Binding Cassette Transporter, Subfamily B, Mem↗

4-Mercaptoimidazoles derived from the naturally occurring antioxidant ovothiols 1. Antioxidant properties.

4-Mercaptoimidazoles derived from the naturally occurring family of antioxidants, the ovothiols, were assayed for their antioxidant properties. These compounds are powerful HOCl scavengers, more potent than the aliphatic thiol N-acetylcysteine. They react slowly with hydrogen peroxide with second order rate constants of 0.13-0.89 M(-1)s(-1). Scavenging of hydroxyl radical occurs at a diffusion-controlled rate (k=2.0-5.0 x 10(10)M(-1)s(-1)) for the most active compounds, which are also able to inhibit copper-induced LDL peroxidation. The combination of radical scavenging and copper chelating properties may explain the inhibitory effects on LDL peroxidation. Two molecules of mercaptoimidazole can chelate a copper ion and form a square planar complex detected by EPR. Compounds bearing an electron-withdrawing group on position 2 of the imidazole ring are the most potent antioxidant molecules in this series.

Antioxidants↗

Paraoxonase activity is dramatically decreased in patients positive for anticardiolipin antibodies.

It has been reported that paraoxonase 1 (PON1) activity inhibits low-density lipoprotein (LDL) oxidation and modulates the risk of coronary heart disease. This study shows that autoantibodies (IgG) directed against modified LDL were increased in 71 patients positive for anticardiolipin antibodies. In a representative subgroup of these patients (n = 36) PON1 activity was dramatically decreased and the prevalence of the RR genotype of this enzyme tended to be increased in patients who had developed arterial thrombosis. This study suggests that PON1 abnormalities play a role in the antiphospholipid syndrome.

Adult↗

Differential toxicities of air (mO-LDL) or copper-oxidized LDLs (Cu-LDL) toward endothelial cells.

In vivo low density protein (LDL) oxidation is a progressive phenomenon leading to the presence of minimally and highly oxidized LDLs in the subendothelial arterial space. Oxidized LDLs have been reported to be cytotoxic against endothelial cells. The goal of this study was to determine which of the minimally and highly oxidized LDLs were the most cytotoxic against bovine aortic endothelial cells (BAEC). Both the morphological aspect of the cells themselves, and LDH or MTT tests revealed that mO- or Cu-LDLs had similar cytotoxicity with up to 8 hours of oxidation, showing no relation with the level of LDL oxidation; for longer oxidation times, Cu-LDL cytotoxicity decreased. This phenomenon is linked to their different oxidation kinetics. Moreover, in the initial hours following BAEC incubation with mO- or Cu-LDLs, total cell glutathione dropped, whereas after 16 hours of incubation, highly oxidized Cu-LDL increased the glutathione level in the cell. The biphasic evolution of glutathione concentration corresponds to an autoprotective mechanism of cells against oxidized LDL cytotoxicity. This study suggests that the specific chemical characteristics of the different types of oxidized LDLs should always be precisely described in future assays devoted to studying the biological effects of what are known under the generic term as "oxidized LDLs". This precaution should prevent any confusion in interpreting different studies.

Adenosine Triphosphate↗

Schistosoma mansoni schistosomula reduce E-selectin and VCAM-1 expression in TNF-alpha-stimulated lung microvascular endothelial cells by interfering with the NF-kappaB pathway.

The recruitment of immune cells into the lungs is a key step in protection against murine schistosomiasis. In this phenomenon, pulmonary (micro)vascular endothelial cells (EC) probably play a central role, by expressing specific adhesion molecules on their surface. Recently, we have shown that Schistosoma mansoni schistosomula, the parasitic stage which resides in the lungs, could activate microvascular EC to acquire an anti-inflammatory phenotype. In the present study, we tested the hypothesis that schistosomula could also regulate the expression of adhesion molecules in vitro by human lung microvascular EC (HMVEC-l) in the present of the pro-inflammatory cytokine TNF-alpha. We found that lipophilic substance(s) present in the excretory/secretory products from schistosomula selectively reduce the TNF-alpha-induced synthesis of E-selectin and VCAM-1 mRNA and proteins without affecting ICAM-1. This inhibitory effect appears to be mediated by a cyclic AMP/protein kinase A (cAMP/PKA) pathway that probably interferes with the NF-kappaB pathway induced by TNF-alpha at the level of the E-selectin promoter, whereas a cAMP-independent pathway appears to operate in VCAM-1 down-modulation. Finally, schistosomula also significantly reduce the VLA-4/VCAM-1-dependent adherence of leukocytes to TNF-alpha-stimulated HMVEC-l. We speculate that this mechanism could represent a new stratagem that parasites may use to escape the immune system by controlling leukocyte recruitment to the lungs.

Animals↗

Structure-activity relationships in a series of melatonin analogues with the low-density lipoprotein oxidation model.

Despite an increasing number of publications concerning the antioxidant activity of melatonin, little is known about the structural features responsible for this kind of activity. To understand the role played by the different elements of melatonin structure in its antioxidant activity, we have designed and tested several compounds related to this molecule in the low-density lipoprotein peroxidation model. We present here the results of this study in terms of structure-activity relationships focusing on the influence of the acetamidoethyl side chain, the methoxy group, and the indole heterocycle. In this model, we found that changing the acyl residue generally resulted in more active products. We obtained particularly good results with the nonanoyl derivative which showed a level of activity comparable to that of phenols despite lacking a phenolic function. The presence of a methoxy group in position 5 generally had a beneficial influence on the activity, but when located in position 6, the effects were various. The substitution of a hydroxy for the methoxy group led to phenolic compounds endowed with very high antioxidant activity. Replacing the amide with a ketone function did not affect the activity while replacement with an amine group in some cases resulted in prooxidant compounds. Finally, we compared the efficacy of different aromatic rings. The indole heterocycle proved to be better than benzofurane and naphthalene rings.

Amides↗