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.

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.

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.

Hypoxia increases the susceptibility to oxidant stress and the permeability of the blood-brain barrier endothelial cell monolayer

Using a cell culture model of the blood-brain barrier (BBB), we investigated the brain capillary endothelial cell (EC) response to hypoxia. The activities of antioxidant enzymes such as glutathione peroxidase, glutathione reductase, catalase, and superoxide dismutase and the GSH level of brain capillary ECs alone or in coculture with astrocytes, as well as those of pericytes, were compared with those obtained with freshly isolated microvessels. These results demonstrated that brain capillary ECs cocultured with astrocytes and used in the presence of a coculture-conditioned medium provided a relevant in vitro model for studying the effect of hypoxia-reoxygenation at the BBB level. The effect of hypoxia on antioxidant enzymes, GSH, and ATP levels was studied, as well as the modification of the permeability to small weight molecules. A decrease in all enzymes and the GSH level could explain an increase in the susceptibility of the brain capillary ECs to further oxidant injury. Second, profound rearrangements of F-actin filaments of the ECs and a decrease in the ATP level could be associated with an increase in the permeability of the monolayer. Furthermore, an apoptotic process was detected by in situ end labeling of DNA. These results indicate that hypoxia distorts the function of ECs and that these cells in culture provide a valuable tool for exploring mechanisms after hypoxia-reoxygenation.

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.

Hypoxia dramatically increases the nonspecific transport of blood-borne proteins to the brain

Increased cerebrovascular permeability is an important factor for the development of cerebral edema. To investigate the effect of hypoxia on the transport of blood-borne proteins to the brain, we used a cell culture model of the blood-brain barrier (BBB) consisting of a coculture of brain capillary endothelial cells and astrocytes that closely mimics the in vivo situation. The permeability of albumin, a marker of the nonspecific transcellular route, is extremely low in this in vitro model of the BBB. After hypoxia, a huge increase in the permeability of albumin is detected. Despite the opening of the tight junctions already demonstrated after hypoxia, the increase in the permeability of albumin is mainly attributed to an increase of the non-specific vesicular transport in the cell, attested by the temperature dependence of the phenomenon and the visualization of labeled apotransferrin in the cytoplasm. The increase of this pathway could participate in the development of brain edema during hypoxia.

Ductal carcinoma in situ of the male breast. Analysis of 31 cases

From 1970 to 1992, 31 pure ductal carcinoma in situ (DCIS) of the male breast treated in 19 French Regional Cancer Centres were reviewed. They represent 5% of all breast cancers treated in men in the same period. The median age was 58 years, but 6 patients were younger than 40 years. TNM classification (UICC, 1978) showed 12 T0 (discovered only by bloody nipple discharge), 10 T1, 5 T2 and four unclassified tumours (Tx). 11 patients (35.5%) had clinical gynecomastia, and three (10%) had a family history of breast cancer. 6 patients underwent lumpectomy, and 25 mastectomy. Axillary dissection was performed in 19 cases. 6 cases received postoperative irradiation. 15 out of 31 lesions were of the papillary subtype, pure or associated with a cribriform component. The size of the 12 measured lesions varied from 3 to 45 mm. All lymph nodes sampled were negative. With a median follow-up of 83 months, 4 patients (13%) presented a local relapse (LR), respectively, at 12, 27, 36 and 55 months. 3 of these patients had been initially treated by lumpectomy. In one case LR was still in situ, but already infiltrating in the 3 others. Radical salvage surgery was performed in 3 cases, but one patient developed metastases and died 30 months later. The last patient was treated by multiple local excisions and tamoxifen. One 43-year-old patient developed a contralateral DCIS and three others developed a metachronous cancer. The aetiology and risk factors of male breast cancer remain unknown. Gynecomastia, which implies an imbalance between androgen and oestrogen, may be a predisposing factor. As in women, DCIS in the male breast has a good prognosis. Total mastectomy without axillary dissection is the basic treatment. Frequently, the first symptom is a bloody nipple discharge. The age of occurrence is younger than for infiltrating carcinoma, suggesting that DCIS is the first step in the development of breast cancer.

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.

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.

1,25-Dihydroxyvitamin D3 regulates gamma 1 transpeptidase activity in rat brain

gamma-Glutamyl transpeptidase (gamma-GT), primarily described as a kidney enzyme, is also expressed in several cell types of the central nervous system (CNS). It is involved in the glutathione cycle and in cysteine transport. Here we report that the specific activity of this enzyme is transiently increased in the rat brain, following a treatment with 1,25-dihydroxyvitamin D3 (1,25-D3), the active form of vitamin D. In vitro experiments showed that this positive regulatory effect does not affect endothelial cells of the brain microvessels, but does affect pericytes and parenchymal astrocytes. Changes in the specific activity of gamma-GT were not correlated with any important modification of brain amino acid concentrations. Since gamma-GT is though to participate in the scavenging of reactive oxygen species, these data suggest that 1,25-D3 could be an effector controlling detoxification processes in the brain.

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.

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.

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.

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.

Radical surgery and conservative treatment of ductal carcinoma in situ of the breast

70 cases of strictly intraductal breast carcinoma were treated from January 1975 to December 1987. 34 patients underwent radical modified mastectomy, and 36 patients had local excision (2), lumpectomy (26) or quadrantectomy (8), with a complementary irradiation in 34/36 cases (with boost in 32). The main histological subtype is comedocarcinoma (25/70). One local relapse (3%) is noted in radical surgery group at 55 months. 3 local relapses (9%) are noted in conservative treatment group, respectively at 27, 48 and 52 months. The obvious factor influencing the local recurrence is the inefficient surgical excision. Since breast screening programs may lead to early duct carcinoma in situ identification, our results suggest that appropriate conservative surgery associated to radiation therapy could be an adequate alternative to mastectomy in the treatment of this in situ lesion.

Rapid quantification of alpha-tocopherol in plasma and low- and high-density lipoproteins

We have developed two methods for measuring the alpha-tocopherol content in plasma and lipoproteins (LDL and HDL). In procedure 1, plasma or lipoproteins are deproteinized with ethanol containing delta-tocopherol as internal standard and then extracted with hexane or ethyl acetate. The organic layer is removed and evaporated, and the residue is redissolved in methanol and injected into a reversed-phase HPLC. In procedure 2, plasma or lipoproteins are diluted in a methanol and ethanol mixture containing the same internal standard. The solution is vortex-mixed, centrifuged, and directly injected into the column. The tocopherols are eluted with an isocratic methanol mobile phase at a flow rate of 1 mL/min and detected by fluorescence (lambda(exc)= 295 nm, lambda(em)= 330nm). Recoveries are approximately 100% in both cases. Between-run CVs were 8.39% for procedure 1 and 6.55% for procedure 2. Small sample requirement, simplicity of sample preparation, short assay time, and good reproducibility make procedure 2 ideal for clinical or research use. This method was applied to determination of alpha-tocopherol in plasma of patients whose diet was supplemented with alpha-tocopherol and in LDL and HDL.

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.

Reduction of a trisulfide derivative of glutathione by glutathione reductase

Glutathione trisulfide was synthesized from glutathione disulfide and its reduction by glutathione reductase was studied. A two-step reaction was observed. In a first step, the rate of reduction was similar to that observed with glutathione disulfide. In addition to glutathione, a persulfide intermediate was detected by an electrochemical method and was carboxymethylated by iodoacetate to be identified by Plasma Desorption Mass Spectrometry. During the second step the reduction of this intermediate led to the formation of hydrogen sulfide and a second equivalent of glutathione.

Concomitant b.i.d. radiotherapy and chemotherapy with cisplatin and 5-fluorouracil in unresectable squamous-cell carcinoma of the pharynx: clinical and pharmacological data of a French multicenter phase II study

PURPOSE

The aim of this phase II study conducted on unresectable squamous cell carcinoma (USCC) of the oro- and hypopharynx was to associate twice-a-day (b.i.d.) continuous nonaccelerated radiotherapy with concomitant cisplatin (CP)-5-fluorouracil (5-FU) chemotherapy, both given at full dose. Feasibility, efficacy, survival, and pharmacokinetic-pharmacodynamic relationships were analyzed.

METHODS AND MATERIALS

Fifty-four consecutive patients with strictly USCC of oro- and/or hypopharynx received continuous b.i.d. radiotherapy (RT) (2 daily fractions of 1.2 Gy, 5 days a week, with a 6-h minimal interval between fractions). Total RT dose was 80.4 Gy on the oropharynx and 75.6 Gy on the hypopharynx. Three chemotherapy (CT) courses of CP-5-FU were given during RT at 21-day intervals (third not delivered after the end of RT). CP dose was 100 mg/m2 (day 1) and 5-FU was given as 5-day continuous infusion (day 2-day 6: 750 mg/m2/day cycle 1, 750 mg total dose/day cycle 2 and 3). Pharmacokinetics was performed for 5-FU (105 h follow-up) and CP (single sample at 16 h). Special attention was paid to supportive care.

RESULTS

Good feasibility of RT was observed (85.2% of patients with total dose > 75 Gy). Five patients received 1 CT cycle, 34: 2 cycles, and 15: 3 cycles. The most frequent and severe acute toxicities were mucositis with grade 3-4 occurring in 28% at cycle 1 and 86% at cycle 2, as well as neutropenia (43% at cycle 2). Locoregional control at 6 months was observed in 66.7% of patients. No late toxicity above grade 2 RTOG was noticed. CP dose and 5-FU AUC(0-105h) were significantly linked to grade 3-4 neutropenia (cycle 2). Cumulative total platinum (Pt) concentration and Karnofsky index were the only independent predictors of locoregional control at 6 months. Finally, total RT dose and total Pt concentration were the only independent predictors of specific survival.

CONCLUSION

This protocol showed good locoregional response with an acceptable toxicity profile. Pharmacokinetic survey is probably an effective approach to further reduce toxicity and improve efficacy. A multicentric randomized phase III study, now underway, should confirm these encouraging results.

Effect of alpha Ni3S2 on arachidonic acid metabolites in cultured human lung cells (L132 cell line)

Our previous investigations have shown evidence of an interaction between alpha Ni3S2 and membranous and cellular lipids of lung cells with a significant increase in the linoleic, linolenic and arachidonic acid pool. The present work is designed to follow the metabolic fate of arachidonic acid in alpha Ni3S2-exposed human embryonic pulmonary epithelial cells (L132) in culture (50 microM alpha Ni3S2 for 3 days). The metabolites of arachidonic acid were assessed by HPLC determination coupled with UV or electrochemical detection. We determined malondialdehyde (MDA), hydroxyeicosatetraenoic acid (HETE), leukotrienes (LT) and reduced glutathione (GSH). In exposed cells we observed a significant increase of MDA, which is a breakdown product of lipid peroxidation. In addition, we noted significant increases of 5-HETE and 15-HETE in L132 cells resulting from the enzymatic reduction of 5-HPETE and 15-HPETE respectively. There was also a simultaneous decrease of GSH--confirmed by a strong decrease of GSH in exposed cells with respect to controls. 5-HPETE is furthermore converted to epoxides such as leukotriene A4 and we also quantified in exposed cells a significant increase of its subsequent catabolites LTB4, LTC4 and LTE4. These investigations show clearly that exposure of L132 cells to alpha Ni3S2 enhances lipid peroxidation based upon direct measurements of MDA and other metabolites of arachidonic acid. This lipid peroxidation is an autocatalytic free-radical process and could be responsible for DNA damage.

A high concentration of melatonin inhibits in vitro LDL peroxidation but not oxidized LDL toxicity toward cultured endothelial cells

The pineal hormone, melatonin, was recently found to be a potent free scavenger for hydroxyl and peroxyl radicals. Melatonin also inhibits neuronal and thymocyte damage due to oxidative stress. Atherosclerosis development is mediated by low-density lipoprotein (LDL) oxidation and the endocytosis of oxidized LDL by resident macrophages in the subendothelial vascular wall. Furthermore, the cytotoxic effect of oxidized LDL increases atherogenicity. The goal of this study was to compare the antioxidant activities of melatonin and vitamin E against in vitro LDL oxidation and their cytoprotective actions against oxidized LDL-induced endothelial cell toxicity. An attempt at loading LDL with melatonin by incubating human plasma with an ethanolic melatonin solution gave only low protection against Cu2+-induced LDL oxidation in comparison with vitamin E and gave no detectable incorporation of melatonin into LDL, measured by high-performance liquid chromatography (HPLC) coupled to UV detection. High concentrations of melatonin (10-100 microM) added to the oxidative medium induced a clear inhibition of Cu2+-induced LDL oxidation, characterized as an increase in the lag-phase duration of conjugated diene formation and decreases in the maximal rate of the propagation phase and in the maximal amount of conjugated diene formation. Determination of the median efficacious dose (ED50) of melatonin and vitamin E by their ability to increase lag-phase duration showed that melatonin was less active than vitamin E (ED50, 79 vs. 10 microM, respectively). Melatonin was also less active than vitamin E in limiting the formation of thiobarbituric acid-reactive substances (TBARS) and LDL fluorescence intensity increase in the medium during Cu2+-induced LDL oxidation. Cu2+-induced LDL oxidation in the presence of 100 microM melatonin produced oxidized LDLs that were less recognizable for the scavenger receptors of J774 macrophages than were untreated LDLs. Vitamin E, 10 microM, was more active than 100 microM melatonin in inhibiting LDL oxidation and the resulting lipoprotein alterations leading to binding internalization and degradation by the J774 macrophages. Vitamin E, 100 microM, inhibited the pursuit of the oxidation of oxidized LDL mediated by bovine aortic endothelial cells (BAECs) in a culture medium containing Cu2+, whereas 100 microM melatonin had no antioxidant effect. Melatonin, 100 microM, as well as 100 microM vitamin E inhibited intracellular TBARS formation during the incubation of BAECs with highly oxidized LDL but had no influence on the increase in glutathione (GSH) concentration during this lengthy exposure (16 h) of BAECs to highly oxidized LDL. During this period, the same dose of vitamin E but not of melatonin tended to limit the decrease in adenosine triphosphate (ATP) concentration. Vitamin E, 100 microM, did not significantly reduce cellular lactate dehydrogenase (LDH) release in the culture medium during the incubation of oxidized LDL with BAECs, whereas 100 microM melatonin dramatically increased this release. These data show that melatonin is less active than vitamin E in inhibiting in vitro LDL oxidation and does not inhibit the cytotoxicity of oxidized LDL toward cultured endothelial cells. The concentrations necessary to inhibit LDL oxidation are far beyond those found in human plasma (100 microM vs. 100 pM). Therefore our results indicate that the pineal hormone melatonin per se appears to have little antiatherogenic property in the in vitro oxidation of LDL and the cytoprotective action against the toxicity of oxidized LDL. Nevertheless, in vivo LDL oxidation takes place in the subendothelium of the artery wall, and nothing is known about the concentration of melatonin or its catabolites in this environment.

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.

Changes in tuberoinfundibular dopaminergic neuron activity during the rat estrous cycle in relation to the prolactin surge: alteration by a mammary carcinogen

An attempt was made to correlate the physiological or the dimethylbenz(a)anthracene (DMBA)-enhanced serum prolactin (PRL) surge, which occurs in the afternoon of proestrus in female Sprague-Dawley (SD) rats, with physiological or pathological changes in two biochemical estimates of the tuberoinfundibular dopaminergic (TIDA) neuron activity. Dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) concentrations as well as tyrosine hydroxylase (TH) activity were measured in the median eminence (ME) of control or DMBA-pretreated SD rats throughout the estrous cycle in relation to PRL secretion. In both groups of females, while the DA content was fairly constant, the DOPAC content and TH activity in the ME fluctuated markedly throughout the estrous cycle. Thus, in control animals, the DOPAC content, DOPAC/DA ratio and TH activity which were stable on the days of diestrus and morning of proestrus were markedly decreased at noon and early afternoon when serum PRL levels began to rise. Later in the afternoon of proestrus, when serum PRL levels were maximal, there was a marked but transient increase in the DOPAC content and DOPAC/DA ratio as well as a brief surge in TH activity. In the evening of the same day, when serum PRL returned to basal levels, the DOPAC content, DOPAC/DA ratio and TH activity were low. Finally on estrus morning, the DOPAC content, DOPAC/DA ratio and TH activity increased again to reach the diestrus levels. In DMBA-pretreated females, similar fluctuations in TIDA neuronal activity occurred during the estrous cycle, but the dynamics of these changes was altered: the DOPAC/DA ratio and TH activity first showed a marked increase in the morning of proestrus day, before decreasing dramatically.(ABSTRACT TRUNCATED AT 250 WORDS)

[Evaluation of immediate breast reconstruction and radiotherapy: factors associated with complications]

OBJECTIVES

To determine prospectively the factors associated with reconstruction failure (i.e. requiring expander removal) and capsular contracture in patients undergoing mastectomy and immediate two-stage breast reconstruction with a tissue expander and implant, and radiotherapy for breast cancer. This is a multi-institutional prospective nonrandomized trial.

PATIENTS AND METHODS

Between 2/1998 and 9/2006, we prospectively evaluated 141 consecutive patients who received 141 implants after mastectomy and underwent chest wall radiotherapy (46 to 50 Gy in 23 to 25 fractions). Patients were evaluated after 24 to 36 months by two senior physicians (radiation oncologist and surgeon).

RESULTS

Medical follow-up was 37 months. Baker 1 and 2 capsular contracture was observed in 67.5% of patients, Baker 3 and 4 in 32.5%. There were 32 reconstruction failures. In a univariate analysis, the following factors were associated with Baker 3 and 4 capsular contracture: surgeon, use of hormonotherapy and smoking, of which only one remained in the multivariate analysis: surgeon. In a univariate analysis, the following factors were associated with reconstruction failure: tumor size T3 or T4, smoking, pN+ axilla. Three factors remained associated with reconstruction failure in a multiple logistic regression: large tumors T3/T4, smoking and pN+ axilla.

CONCLUSIONS

Mastectomy, radiotherapy and immediate breast reconstruction with a tissue expander and implant should be considered when breast conserving surgery has been denied. Adequate patients can be easily selected by using three factors of favourable outcome.

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).