Biomedical subjects

N Lequeux

Publications and source records attributed to N Lequeux.

11 recordsLinked to original sources

PubMed2005

Microstructure evolution of hydrated cement pastes.

We propose an original method based on both proton nuclear magnetic relaxation dispersion and high-resolution NMR spectra to investigate the microstructure of synthesized Ca3SiO5-hydrated cement paste. This method allows a clear assessment of the local proton chemical sites as well as the determination of dynamical information of moving proton species in pores. We show also how the microstructure evolves during and after completion of hydration in a range of length scales between 2 and 500 nm. In particular, we show how the pore size distribution of the cement paste reaches progressively a power-law characteristic of a surface-fractal distribution with a dimension Df = 2.6, which takes into account the hierarchical order in the material. Last, we study how this pore size distribution is modified during setting by varying either the water-to-cement ratio or addition of ultrafine particles. This shows that our method could be relevant to relate the mechanical properties to the microstructure of the material. This proposed NMR method is general enough for the characterization of microstructure of any porous media with reactive surface involving water confinement.

Journal Article↗

PubMed2000

Immunocytochemical assessment of sigma-1 receptor and human sterol isomerase in breast cancer and their relationship with a series of prognostic factors.

The purpose of this study was to immunocytochemically investigate two new markers, the sigma-1 receptor and the human sterol isomerase (hSI), in comparison with a series of clinicopathological and immunocytochemical prognostic factors in a trial including 95 patients with operable primary breast cancers. Our results showed no statistically significant relationship between these two markers and the age of the patients, their menopausal status, the tumour size and its histological grade, the nodal status and the expression of the Ki-67 proliferative marker. However, we evidenced a close correlation between the sigma-1 receptor expression and the hormonal receptor positivity (P = 0.008), essentially due to a link with the progesterone receptor status (P = 0.01). By contrast there was an inverse relationship between hSI expression and the oestrogen receptor and/or progesterone receptor positivity (P = 0.098). A significant relationship was shown between both the sigma-1 receptor, hSI expressions and Bcl2 expression, with P= 0.017 and 0.035 respectively. We also assessed whether the expression of the sigma-1 receptor or hSI might be linked with disease-free survival (DFS) and found that the presence of hSI and the absence of sigma-1 receptor expression were associated with a poorer disease-free survival (P= 0.007). Altogether these results suggest that in primary breast carcinomas in association with the evaluation of the steroid receptor status, the sigma-1 receptor and hSI may be interesting new markers useful to identify those patients who might be able to benefit from an adjuvant therapy.

Adult↗

PubMed2000

[Determination, by in situ hybridization on interphasic nucleus, a cytogenetic DNA index; application to breast cancer; comparison of this DNA index to DNA indexes determined by imaging and flow cytometry].

In oncology, flow cytometry (FCM) and image cytometry (ICM) are commonly used to detect DNA aneuploid cell populations in solid tumors. Agreement between these two approaches is good. The use of both techniques in association minimizes the rate of FCM and ICM false negatives and gives better DNA pattern characterization, particularly for detection of any tumoral component in the FCM DNA diploid peak. Nevertheless, discrepancies exist between the FCM and the ICM DNA index values: the ICM DNA index is often greater than the FCM DNA index. The aim of the present study was to establish a cytogenetic DNA index by determining the chromosomal ploidy using a molecular cytogenetic approach and to compare it to the FCM and ICM DNA indexes. We present here the fluorescence in situ hybridization (FISH) technique we have adapted to the study of breast cancer in order to count the number of copies of the 22 + X human chromosomes in interphasic nuclei. This was achieved using a panel of 21 indirect FITC labeled probes which recognize specific chromosomic DNA sequences. Preliminary results obtained from DNA diploid and DNA aneuploid tumors are discussed.

Breast Neoplasms↗

PubMed1997

Expression of the interleukin 6 receptor in primary renal cell carcinoma.

AIMS: Interleukin 6 (IL-6) is expressed in the majority of renal cell carcinomas and has an important role in the proliferation of some renal cell carcinoma cell lines. This action is mediated by two membrane proteins, gp80 (the IL-6 receptor; IL-6R), which binds IL-6, and gp130, which transduces the signal. The soluble form of gp80 (sIL-6R) is able to activate gp130 when complexed to the IL-6 molecule. These considerations prompted an investigation of IL-6R expression in this malignancy. IL-6, C reactive protein (CRP), and sIL-6R were also measured in serum and correlated to clinical and pathological features. METHODS: Immunostaining was performed on cryostat sections from renal cell carcinoma tumours with M91, an anti-IL-6R monoclonal antibody, using the alkaline phosphatase antialkaline phosphatase technique. The proliferation index was measured using the KI-67 monoclonal antibody. CRP, IL-6, and sIL-6R were measured in serum before nephrectomy, using an immunoenzymatic or immunoradiometric assay. RESULTS: There were significant differences in survival in patients with tumours larger than 8 cm, metastasis at diagnosis, high nuclear grade tumours, detectable serum concentrations of IL-6 (correlated to CRP serum concentration), more than 4% proliferating cells, and the presence of the IL-6R in situ. Furthermore, the serum IL-6 concentration correlated with tumour size and stage. The mean serum sIL-6R concentration was not significantly different from that observed in 40 normal subjects. Tumour IL-6R expression was present in 10 samples. There was a significant association between the presence of the IL-6 receptor in tumours and tumour stage, nuclear grade, proliferation index, and serum IL-6. CONCLUSIONS: This study revealed the importance of IL-6/CRP and IL-6R expression in situ as potential new prognostic factors and opens the way to new therapeutic strategies in renal cell carcinoma.

Adult↗

PubMed1997

Prostaglandin H synthase 1 and 2 immunoreactivities in the bronchial mucosa of asthmatics.

Prostaglandin H synthases or cyclooxygenases 1 (PGHS-1) and 2 (PGHS-2) catalyze the conversion of arachidonic acid to prostaglandin endoperoxides, leading to the formation of prostaglandin and thromboxane mediators of inflammation. The expression of these enzymes in the respiratory epithelium has not been determined, although they may be relevant to the pathophysiology of inflammatory disorders such as asthma and chronic bronchitis (CB). We studied PGHS-1 and PGHS-2 immunoreactivity in bronchial biopsies obtained from 22 patients with chronic stable asthma, seven patients with CB, and 12 normal subjects. Both types of PGHS were mainly expressed in the epithelium (basal and ciliated cells), and PGHS-1 and PGHS-2 were found in 21 of 41 and 34 of 41 biopsies, respectively. We did not find any differences in PGHS expression between the patient populations. There were no correlations between any of the clinical parameters studied or the pathologic patterns and the presence and characteristics of the PGHS immunoreactivities. Thus, both PGHS enzymes are expressed in normal human respiratory epithelium and are not quantitatively upregulated in the main bronchi in stable asthma and CB.

Adrenal Cortex Hormones↗

PubMed1994

Assessment of inflammation in noninfectious chronic maxillary sinusitis.

BACKGROUND AND AIM: Pathologic examination of the sinus mucosa and titration of inflammatory mediators in the sinus fluid were carried out to characterize inflammation in chronic sinusitis and determine whether patients with chronic allergic rhinitis (CAR) and sinusitis differ from patients with chronic nonallergic rhinitis (CNAR) and sinusitis. METHODS: Nine control subjects (patients requiring ear, nose, and throat surgery not related to sinusitis), 12 patients with CAR and sinusitis, and 13 patients with CNAR and sinusitis were investigated. Eosinophil cationic protein, tryptase, myeloperoxidase, histamine, and prostaglandin D2 were measured in the sinus lavage fluids, and cells were enumerated. The cellular infiltrate was studied by immunohistochemistry with monoclonal antibodies against eosinophil cationic protein (eosinophils), tryptase (mast cells), neutrophil elastase (neutrophils), CD3 (lymphocytes), CD68 (macrophages), and proliferating cell nuclear antigens. RESULTS: Neutrophils were not increased in sinusitis. In comparison with control subjects, patients with CAR and CNAR with sinusitis showed significant increases in eosinophils and macrophages in biopsy specimens and in eosinophil cationic protein in sinus lavage fluids. In comparison with patients with CNAR, patients with CAR had an increased number of intraepithelial mast cells and lymphocytes. CONCLUSIONS: These findings suggest that patients with CNAR and sinusitis can be distinguished from patients with CAR and sinusitis, which resembles nonallergic rhinitis with eosinophilia syndrome.

Adolescent↗

PubMed1994

Cell proliferation in the bronchial mucosa of asthmatics and chronic bronchitics.

In chronic inflammatory diseases, cells are recruited but may also derive from local proliferation. In normal bronchial epithelium, under 5% of cells are in cycle but in asthma and chronic bronchitis, proliferation may occur. Cycling cells can be identified by immunohistochemistry using PC10 monoclonal antibody (Proliferating Cell Nuclear Antigen, PCNA). We enumerated PCNA-positive cells (labeling index = LI) in bronchial biopsies of 11 healthy non-smokers (HNS), seven healthy smokers (HS), 30 non-smoking asthmatics (NSA), six smoking asthmatics (SA) and 18 chronic bronchitics (CB). Twenty non-small cell lung cancer patients were used as positive control subjects. Ciliated and secretory cells were PCNA-negative. Basal cells were PCNA-positive in one of the 11 HNS (LI = 0.18 +/- 0.60), none of the seven HS, two of the 30 NSA (LI = 0.05 +/- 0.20), two of the six SA (LI = 2.4 +/- 4.3) and 11 of the 18 CB (LI = 12 +/- 20). In smokers, PCNA positivity correlated with tobacco consumption (Rho = 0.62, p < 0.0008) and in patients with chronic bronchitis, with the degree of metaplasia (tau = 0.815, p < 0.0001). The submucosa of most subjects showed no PCNA immunoreactivity. These findings suggest that the bronchial mucosa of nonsmokers is not hyperproliferative, even in asthmatics. Tobacco smoking increases PCNA immunoreactivity, possibly leading to the metaplasia of chronic bronchitis.

Adolescent↗

PubMed1994

Quantification of ERBB2 protein expression in breast cancer: three levels of expression defined by their clinico-pathological correlations.

Activation of the ERBB2 oncogene seems to be an early event in breast cancer progression and prevalent in in situ carcinomas. However, its prognosis value, albeit recognized for node-positive patients, remains controversial for those without apparent nodal involvement. One possible reason for this problem is likely to be the difficulty of defining threshold levels for ERBB2 protein overexpression. ERBB2 protein expression was therefore analyzed in primary invasive breast tumors. Quantification of the gene product by a commercial ELISA test was compared to results obtained by immunohistochemistry and western blotting, as well as to gene amplification status determined by Southern blotting. Correlations between results obtained by the different techniques were highly significant (P value < 10(-6)). Nevertheless, ELISA permitted us to determine three levels of protein expression corresponding to distinct tumor subsets. 1) Tumors with p185/ERBB2 expression levels exceeding 10 U/microgram exhibited in most cases amplification of the gene (83% of cases), DNA aneuploidy (81%) and absence of estrogen receptor (ER) (44%). Such high levels of protein expression were exclusively observed in invasive ductal carcinomas and were prevalent in those showing a significant in situ component. 2) "Intermediate" levels of expression (3-10 U/micrograms) were rarely observed in tumors exhibiting gene amplification (9%), but were preferentially found in cancers of more favorable prognosis (only 49% were aneuploid and 9% estrogen receptor negative). 3) Levels of p185/ERBB2 below 3 U/micrograms were detected in benign mastopathies and, thus, carcinomas presenting such levels were scored ERBB2 negative. Interestingly, invasive lobular carcinomas were rarely ERBB2 positive, and if so, only at intermediate levels. Moreover, our data show a complex interrelationship between p185/ERBB2 expression and ER levels. Indeed, tumors with more than 10 U/micrograms of p185 were prevalently ER, whereas those with p185 ranging from 3 to 10 U presented elevated levels of ER.

Aneuploidy↗

PubMed1991

Cytofluorometric detection of human endothelial cells in whole blood using S-Endo 1 monoclonal antibody.

It has long been debated whether endothelial cells are present at very low frequency in peripheral blood. Elevated concentrations of such circulating cells may represent a good marker of vascular injury. We have therefore designed an immunocytometric assay for the detection of rare endothelial cells in whole blood. This assay is based on a new monoclonal antibody (MAb) S-Endo 1, made against human umbilical vein endothelial cells (HUVEC) and specific for endothelial cells of various origins without detectable reactivity with blood cells. First, the sensitivity of the assay was established by using normal blood samples with admixed HUVEC as an in vitro model. A good correlation was obtained between added and counted endothelial cells; the recovery was greater than 90% and the minimum detectable concentration of HUVEC was about 0.2 cells/microliters whole blood. Using this rapid counting technique, no detectable levels of endothelial cells were found in the blood of normal individuals (CE less than or equal to 0.1 cells/microliters) while elevated concentrations (up to 8 cells/microliters) were detected in a human model of vascular injury corresponding to a traumatic venepuncture. Thus, this new whole blood immunocytometric assay using S-Endo 1 MAb may be useful in determining the levels of circulating endothelial cells in vascular disorders.

Animals↗

PubMedDate not supplied

Micropore size analysis in hydrated cement paste by NMR.

We present a time evolution of 1H spin-lattice relaxation rates in the laboratory (1/T(1)) and in the rotating frame (1/T(1rho)) of a synthetic cement paste. The typical results found for both rates allows us to follow the main hydration stages of the cement paste and the refinement of its microporosity. In particular the texturation of the porosity and the structuration of the surface of the material is evidenced.

Calcium Compounds↗

PubMedDate not supplied

Micropore size analysis by NMR in hydrated cement.

The understanding of the microstructure of cement remains incomplete. Especially, the progressive setting of the material is still unclear. Micropore size distribution (microstructure) has been investigated by both standard proton nuclear magnetic relaxation (1H-NMR) and field-cycling relaxation in C3S hydrated paste. The non-exponential decay was interpreted as a distribution of discrete relaxation rates. The attribution of T1 is supported by both a spectral and a dispersion curve analyses. These experiments allow us to follow the structuration of the material during setting.

Calcium Compounds↗