Biomedical subjects

H Magdelenat

Publications and source records attributed to H Magdelenat.

At least 55 records · Page 3Linked to original sources

PubMed1992

Genetic evolution of breast cancer: II. Relationship with estrogen and progesterone receptor expression.

The expression of estrogen (ER) and progesterone (PR) receptors was assayed by steroid binding in a series of 95 malignant breast tumors, for which the analysis of chromosome aberrations was performed and allowed the reconstruction of their chromosomal evolution. It was shown that breast tumors undergo a progressive loss of chromosomes, with occasionally one and rarely two endoreduplications. Chromosome losses were often the consequence of rearrangements, and the rate of rearranged chromosomes, which increases progressively, appeared as a possible indicator of tumor progression. The distribution of ER and PR values in the sample of 95 tumors was compared to that of a larger control series of consecutive cases: 598 for ER and 460 for PR. The similarities of the distributions indicated that the sample of 95 tumors was representative of the general population of breast cancers. The levels of ER and PR expression were very strongly and negatively correlated to the rate of rearranged chromosomes, but not to the modal number of chromosomes. However, when tumors having either undergone endoreduplication or not (greater than 50 or less than 51 chromosomes, respectively) were considered separately, a significant correlation between ER and PR expression and chromosome number was found within each group. Finally, breast cancers were subdivided into 4 stages of cytogenetic evolution, from the least to the most evolved: stage 1: less than or equal to 50 chromosomes, less than 25% rearranged chromosomes; stage 2: greater than 50 chromosomes, less than 25% rearranged chromosomes; stage 3: less than or equal to 50 chromosomes, greater than 25% rearranged chromosomes; stage 4: greater than 50 chromosomes, greater than 25% rearranged chromosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗

PubMed1991

Estrogen and progesterone receptors in cervical human papillomavirus related lesions.

According to recent studies showing that human papillomavirus (HPV) infections can be influenced by sex steroid hormones, we performed estrogen (ER) and progesterone (PgR) receptor assays in fresh frozen biopsies of genital-HPV-related lesions. Seventy-three women with normal cervix, condyloma, low- and high-grade CIN and squamous carcinoma were evaluated in comparison with 15 persons with vulvar and 9 with penile papillomavirus-associated lesions. HPV genotypes were determined by dot-blot hybridization. Non-cervical lesions did not express HR. Condyloma on squamous metaplasia of the cervix and high-grade CIN expressed high levels of HR, particularly PgR (mean 4,086 and 4,518 fmoles/g tissue, respectively). Cervical squamous carcinoma expressed very low concentrations of PgR in a limited number of cases. High levels of PgR were correlated with high-grade CIN (p less than 0.05), HPV16-18-associated lesions (p less than 0.01) and ER were correlated to HPV6-11-related lesions (p less than 0.01). The levels were independent of age, cycle stage and oral contraception. Morphological localization of PgR, using an immunocytochemical method using a monoclonal antibody (MAb) (PR-ICA), showed intense homogeneous staining in the nuclei of the stromal fibroblasts underlying dysplastic epithelium and condyloma on squamous metaplasia. These results suggest that, under in vivo conditions, sex steroid hormones, particularly progesterone, may act indirectly on HPV-infected epithelial cells and be implicated as co-factors in HPV-related cervical neoplasia. They could explain the relative predisposition to malignant transformation of the cervix as compared with vulvar and penile mucosa.

Adult↗

PubMed1991

Impossibility of acridine orange intercalation in nuclear DNA of the living cell.

The ability of a "vital" dye, acridine orange (AO), to intercalate into the DNA of living cells was investigated by quantitative intensified fluorescence microscopy and digital imaging under various conditions of dye concentration, excitation light intensity, and ionic concentration. Our results demonstrate that the bulk of chromatin DNA is packed in a way that does not allow AO intercalation. At low dye concentrations and very low levels of light intensity, the only fluorescent structures observed inside the nucleus are the nucleoli. This nonpermissive state of the chromatin appears to be a characteristic feature of the nucleus in living cells. AO intercalation into DNA can be mediated by raising the nuclear Na+ concentration. This was achieved here by using a cation carrier, monensin, a procedure which permits the avoidance of cell permeabilization. Furthermore, we show that the discharge of lysosomal enzymes in the living cell, via a targeted photodynamic reaction which occurs at high levels of light intensity, can also release the constraints which impede dye intercalation into nuclear DNA. In conclusion, studies carried out under conditions where intercalative dyes such as AO are able to stain the nuclear DNA have to be interpreted with caution and do not provide direct evidence on the structural state of native chromatin. The molecular origin of the absence of AO intercalation in chromatin of the living cell is discussed with regard to the restrained uncoiling of the double helix which is required for dye intercalation.

Acridine Orange↗

PubMed1991

Increased intraplatelet levels of platelet-derived growth factor and transforming growth factor-beta in patients with myelofibrosis with myeloid metaplasia.

Platelet-derived growth factor (PDGF) is thought to play some role in the genesis of fibrosis associated with myeloproliferative disorders. In addition, transforming growth factor-beta (TGF-beta) has been confirmed to promote fibrotic process. Both PDGF and TGF-beta have been shown to cooperate with epidermal growth factor (EGF) in regulating the growth of human marrow fibroblasts. All three are contained in platelet alpha-granules. We report the results of a study in patients with myelofibrosis with myeloid metaplasia (MMM). We evaluated PDGF, TGF-beta and EGF-like activities in circulating platelets from patients compared to healthy subjects. In contrast to EGF-like intraplatelet levels which were similar in patients and in normal donors (1-4 ng/10(9) platelets), we found constantly higher values for both PDGF and TGF-beta in MMM patients. In both radioimmunoassay (RIA) and assay for mitogenic activity on human bone marrow fibroblasts, PDGF levels were increased on the average 2-3.5-fold over the levels found in normal donors (P less than 0.01 and P less than 0.001, respectively). PDGF serum levels in patients were consistent with those found in platelets. In platelet-poor plasma (PPP), PDGF concentrations were undetectable or congruent to 2 ng/ml in patients and in control donors as well. The total TGF-beta activity in platelet lysates, determined using a competitive radioreceptor binding assay on Swiss 3T3 mouse cells and an inhibition growth assay on CCL64 cells, was found 2-3-fold increased in patients with MMM as compared to control subjects (P less than 0.003). These results emphasize that, not only PDGF, but also TGF-beta are implicated in the myelofibrosis with myeloid metaplasia.

Adult↗

PubMed1991

Interferon-gamma in vivo reverses the increased platelet levels of platelet-derived growth factor and transforming growth factor-beta in patients with myelofibrosis with myeloid metaplasia.

We previously reported high platelet-derived growth factor (PDGF) and transforming growth factor beta (TGF-beta) levels in platelets from patients with myelofibrosis with myeloid metaplasia. We report here the effects of in vivo administration of recombinant human interferon-gamma on these growth factor levels. Of six patients who entered this study in our institution, four completed the 6-month therapy trial with interferon-gamma PDGF and TGF-beta levels in platelets were evaluated before and after treatment. PDGF levels were determined using a radioimmunoassay and TGF-beta activity was measured using an inhibition growth assay on CC164 cells. In these four patients, IFN-gamma therapy led to a reduction of the increased PDGF and TGF-beta levels in platelets towards the normal range. PDGF and TGF-beta values decreased by 25-45% and 32-46%, respectively. An acute deterioration was observed in one patient 5 months after the end of IFN-gamma therapy. In this patient, the deterioration of his clinical state correlated with an increase in intraplatelet PDGF and TGF-beta levels.

Adult↗

PubMed1990

A simplified immuno-enzymetric assay of the epidermal growth factor receptor in breast tumors: evaluation in 282 cases.

The epidermal growth factor receptor (EGF-R) is currently being investigated in human clinical oncology, and particularly in breast cancer, as a potential prognostic factor and a biological target for therapy. As an alternative to the 125I-EGF binding assay, we propose a sensitive immuno-enzymetric assay (IEMA) suitable for EGF-R assay in breast cancer. The assay is performed on solubilized extracts of the 105,000 g pellet of a tumor homogenate, allowing estrogen (ER) and progesterone (PR) assays to be made on the cytosol. The IEMA is performed on 96-well plates coated with the monoclonal anti-EGF-R antibody RI, through an anti-mouse IgG2b bridge. Trapped EGF-R in the samples is covered by a second monoclonal antibody (MAb), 528, and revealed by an anti-IgG2a-peroxidase complex. The sensitivity is 1 fmol/mg membrane protein, and the asay can be performed on tissue samples down to 50 mg. Two hundred and twenty primary ductal breast carcinomas assayed by this method showed a log normal distribution with a modal value of 8 fmol/mg prot., a mean at 18 and a median at 13 fmol/mg prot. EGF-R-rich tumors (greater than 20 fmol/mg prot.) were highly correlated with the absence of estrogen receptors and/or with a high histological grade (SBR III). Our data demonstrate the validity of the IEMA assay of EGF-R in human breast tumors.

Breast Neoplasms↗

PubMed1990

Presence of villin, a tissue-specific cytoskeletal protein, in sera of patients and an initial clinical evaluation of its value for the diagnosis and follow-up of colorectal cancers.

Villin is an actin-binding protein found in a few normal adult epithelia, namely epithelial cells in the digestive and urogenital tracts. Moreover, villin production is maintained in malignant cells. We assumed that cell lysis and necrosis of solid tumors producing villin might result in villin release into blood. We analyzed the villin content of sera from 788 patients and controls using an enzyme-linked immunosorbent assay. Patients and controls were classified into healthy donors, patients with benign diseases of the gastrointestinal tract, patients with colorectal cancers, and patients with malignant nondigestive diseases. In the panel of sera analyzed, the sensitivity of the assay for colorectal cancers was 50.5%, and its overall specificity for malignant digestive tumors was 94.5%. Results were statistically analyzed comparing each group of sera with each other. We conclude that the presence of villin is indicative of a pathological state in the gastrointestinal tract (P less than 0.001). Finally, we followed villin levels after tumor resections (60 patients). We found that the villin level in sera remains low in remissions but is raised in recurrences. We suggest that the villin assay may have clinical utility as a diagnostic adjunct for adenocarcinoma of the gastrointestinal tract. It may also have some value in monitoring patients with advancing colorectal carcinomas after resection of these tumors.

Adult↗

PubMed1990

Genotoxic effects of radiotherapy and chemotherapy on the circulating lymphocytes of breast cancer patients. I. Chromosome aberrations induced in vivo.

Unstable chromosome aberrations were scored in peripheral blood lymphocytes (PBL) serially collected from 21 breast cancer patients before and after radiotherapy (RT), chemotherapy (CT) and combined treatments. Local radiotherapy as treatment for mammary cancer induced unstable chromosome aberrations in peripheral blood lymphocytes. Only a fraction of these lymphocytes were exposed to irradiation during treatment and the chromosomal damage observed in PBL was equivalent to that induced by irradiation in vitro with 2 Gy at high dose rate, i.e., about 4% of the total dose delivered locally. Chemotherapy alone did not induce such anomalies. Apart from the observed interindividual variations in either the level or the fate of dicentrics with time, different features of chromosome damage were found when chemotherapy was given before or after local cobaltotherapy: secondary chemotherapy did not alter the frequency and the overdispersed distribution of dicentrics observed after first-line radiotherapy; in contrast, when CT was given before radiotherapy, a lower dicentric frequency was scored, the distribution of dicentrics was not always found to be overdispersed and there was a time-dependent decrease in dicentrics after in vivo exposure.

Breast Neoplasms↗

PubMed1990

Genotoxic effects of radiotherapy and chemotherapy on the circulating lymphocytes of breast cancer patients. II. Alteration of DNA repair and chromosome radiosensitivity.

Lymphocytes from 43 breast cancer patients were tested for their DNA-repair ability and in vitro chromosomal radiosensitivity. Lymphocytes were collected before and after treatment with radiotherapy or chemotherapy or both, and then irradiated in vitro. The aim was to detect alterations of these 2 indicators of radiosensitivity, in relation to cancer status or medical treatment. Patients before treatment were significantly deficient in DNA-repair ability but had a normal chromosomal radiosensitivity as compared to healthy donors. When assessed after treatment, DNA-repair ability and the frequency of in vitro-induced chromosome anomalies were modified according to the type of treatment. A reduced DNA-repair ability was observed for patients after radiotherapy but not after chemotherapy. In vitro-induced dicentrics and acentrics were not modified to the same extent according to the treatment. A decreased number of acentrics (the most frequently observed alteration) was preferentially associated with a more reduced DNA-repair ability. Interindividual differences of response to in vitro irradiation tested by both assays were observed between patients who had undergone similar treatments. The possibility that these assays could be used for predicting individual susceptibility to radiation or chemotherapy drug exposure is discussed.

Adult↗

PubMed1990

Ki67 index and S-phase fraction in human breast carcinomas. Comparison and correlations with prognostic factors.

In a prospective study of 148 consecutive breast adenocarcinomas, proliferative indices of the same surgical tumor sample were performed by immunohistologic staining (Ki67 index) with the use of the Ki67 monoclonal antibody, which binds to a nuclear antigen only expressed in cycling cells, and by flow cytometry-derived S-phase fraction (SPF). Measurable Ki67 and SPF indices were obtained in 142 cases and 99 cases, respectively, and in 96 cases by both methods. In aneuploid tumors, a significant but low (P less than 0.05, r = 0.3) relationship was observed between Ki67 index and SPF. When compared with clinical, pathologic, and biochemical parameters these two proliferative indices were shown to be associated with nuclear grading and mitotic index. Additionally, correlations were observed between Ki67 index and node involvement (P less than 0.02) and between SPF and estrogen receptors (P = 0.002). These results show that (1) proliferative indices are obtained in 96% of surgical samples with Ki67 versus 67% with SPF and that (2) Ki67 index and SPF may provide complementary data with respect to prognosis.

Adenocarcinoma↗

PubMed1989

Receptor binding of NBD-labeled fluorescent estrogens and progestins in whole cells and cell-free preparations.

We have studied the interactions of four fluorescent steroid conjugates with either the estrogen or progesterone receptor, both in whole cells and cell-free receptor preparations. The fluorophore, nitrobenzoxadiazole (NBD), was conjugated with a synthetic progestin, with a steroidal estrogen, a non-steroidal estrogen, and with an antiestrogen. With all compounds, receptor-specific binding could be detected by fluorescence measurements following extraction from the protein into an organic solvent. In the native state, however, the NBD-ligand-receptor complex is essentially non-emissive, although these ligands fluoresce strongly when associated with non-specific binders such as albumin. The binding site concentrations and relative affinities determined by fluorescence (after extraction) correspond well with those determined by [3H]estradiol or [3H]R5020 binding to their respective receptors. In T47D breast cancer cells, the NBD-progestin showed receptor-mediated uptake and nuclear localization. These compounds have provided valuable information about the interactions of low and medium affinity ligands with their receptors; however, the successful use of fluorescent ligands for detecting steroid receptors under native-bound conditions, by "imaging" modalities (fluorescence microscopy and flow cytometry) will require the development of fluorophores that are emissive while receptor bound or assay protocols that enable the environment of ligands associated with the receptor to be controlled.

Affinity Labels↗

PubMed1989

Chromosomal aberrations and DNA repair ability of in vitro irradiated white blood cells of monkeys previously exposed to total body irradiation.

Six monkeys (Macaca fascicularis) were total-body-irradiated with 60Co (fractionated irradiation of 8 or 10 Gy). Blood samples were collected at different times post total-body irradiation, then in vitro irradiated in order to test whether a prior in vivo irradiation could affect the radiosensitivity of their leukocytes. We suggested in a preliminary report that the enhanced chromosomal radiosensitivity of in vivo irradiated monkeys could be correlated with a DNA repair deficiency (Guedeney et al., 1986). Chromosomal aberrations, the rate of initial strand breaks and their rejoining estimated using a fluorescent assay for DNA unwinding were chosen as the endpoints in this more extensive study. We observed that the yield of dicentrics induced by a subsequent in vitro irradiation was lower than that scored in unirradiated monkeys in few cases (6/22) whereas the number of acentrics was found to be modified in 16 of the 22 samples. An altered DNA repair ability was observed in most but not all blood samples tested. Thus, in view of such intra-individual variability, the results of this more extensive study lead us to conclude that a previous total-body irradiation does not alter the gamma-induced chromosome aberrations and DNA repair ability in a reproducible manner.

Animals↗

PubMed1989

Long term bone marrow culture in metastatic neuroblastoma.

We have developed a long term marrow culture assay for the study of advanced bone marrow metastatic neuroblastoma. In this in vitro system the hemopoietic growth (GM-CFU) is not affected by the presence of tumor cells. The neuroblastoma cells grow and differentiate partially when in contact with the stromal layer, arresting the culture. We present culture and histological data suggesting that the solid tumors interact specifically with the stromal layer of marrow origin.

Bone Marrow↗

PubMed1989

Mapping of single-copy DNA sequences on human chromosomes by in situ hybridization with biotinylated probes: enhancement of detection sensitivity by intensified-fluorescence digital-imaging microscopy.

Two single-copy DNA segments of 6 kilobases (kb) and 2.3 kb were labeled with biotin-labeled dUTP (Bio11-dUTP) and hybridized to human chromosomes. These probes were detected by immunofluorescence and directly mapped on chromosomes by using classical fluorescence microscopy and a microchannel-plate-intensified video camera. By a subsequent R-banding, the 6-kb and 2.3-kb fragments were precisely localized to the 18p11.3 band and to the 22q11.2 band, respectively, in agreement with previous results obtained with radioactive probes. The adaptation of fluorescence intensification and digital image processing (frame integration to enhance signal-to-noise ratio and linear contrast stretching) to microscopy makes it possible to detect very weak fluorescent spots on chromosomes. This system allows a high spatial resolution (less than 0.6 micron), even at very low fluorescence levels. The efficiency and the specificity of the hybridization and detection methodology give a direct and precise localization of the short single-copy sequences on human chromosomes.

Base Sequence↗

PubMed1989

[Immunohistochemistry of epidermal growth factor receptors in human meningioma].

EGF receptors were assayed by immunohistochemistry using a monoclonal antibody against EGF-R in 32 surgical samples of meningioma. EGF-R were found in all samples (32/32). Only tumor cells were stained and staining was homogenous in tumor tissue. EGF-R was simultaneously assayed by 125I-EGF binding on membrane preparation and immunohistochemistry on frozen sections in 10 meningiomas. Results were qualitatively equivalent in 9 cases. Staining intensity was not correlated with the histological type, the proliferative status of the tumor or the age and hormonal status of the patients. The immunohistochemical data are in agreement with previous biochemical assays on tissue homogenates.

ErbB Receptors↗

PubMed1988

Monoclonal antibodies for progesterone receptor assays and polymorphism studies in breast cancer. Comparison with radioligand assays.

Progesterone receptors (PR) from human breast tumors were assayed by a new method using monoclonal antibodies immobilized on beads (PR-EIA, Abbott Laboratories). EIA results were compared to those obtained with the dextran-coated charcoal method using a tritiated ligand (ORG 2058). The precision and reproducibility of the EIA method were studied over a 3-month period: intra-assay coefficients of variation were less than 6% for the range of the assay (between 5-250 fmol/ml), and inter-assay coefficients of variation calculated on 13 consecutive standard curves were less than 10%, except for standard 0 (33%). PR assays performed on 78 tumors both by EIA and radioligand (RLA) were compared. The linear regression obtained was: PR-EIA = 0.81 RLA+1 fmol/mg protein (r = 0.88). For reproducibility studies, cytosols were assayed twice during a period ranging from 1 week-3 months, both by EIA and RLA. The linear regression obtained between the second assay (B) and the first assay (A) was: B = 0.98 A + 11 fmol/mg protein for RLA (r = 0.98), and B = 0.99 A-7 fmol/mg protein for EIA (r = 0.98). To study the effect of KCl on PR-EIA, 26 tumors were homogenized in 0.4 M KCl Tris buffer and assayed both by EIA and RLA. A good correlation was obtained between the 2 methods, but higher values were obtained with PR-EIA (P = 1.6) in comparison with RLA. The addition of KCl to the cytosol showed that KCl had no effect on EIA results, but significantly lowered RLA results. To study the effect of KCl on progesterone receptor isoforms, cytosols were analyzed by chromatography on TSK G3000 SW columns, and the presence of PR was detected in each fraction by both EIA and RLA. In the absence of KCl, only the oligomeric form of PR was observed; however with both techniques, detection of this form different from tumor to tumor, emphasizing the inter-tumoral molecular heterogeneity of PR. After PR isoform dissociation by KCl (0.4 M) and chromatographic analysis of the forms obtained, monoclonal antibodies detected PR molecular forms different from those observed by radioligand; furthermore, chromatographic patterns obtained were different from one tumor to another and confirmed the inter-tumoral molecular heterogeneity of the progesterone receptor.

Antibodies, Monoclonal↗

PubMed1988

[EGF receptors (epidermal growth factor) and steroid receptors in human meningioma].

Epidermal growth factor receptor (EGF-R) were assayed by 125I-EGF binding in 28 surgical samples of human meningiomas. High affinity EGF-R were found in 26/28 tumors (92 p. 100) at concentrations ranging from 20 to 410 femtomoles per mg of membrane protein (fmol/mg prot. mb.). In 18/26 cases (64 p. 100), the EGF-R concentration was between 95 and 230 fmol/mg prot. mb. No relationship was found between the EGF-R level and the site or histopathology of the tumor. The only noticeable observations were the low levels of EGF-R in the 3 anaplasic meningiomas as compared to the whole population and the undetectable level of EGF-R in the angiomatous tumors. In addition, no correlation was found between EGF-R levels and the hormonal status of the patients, nor between EGF-R levels and the intratumoral concentration of progesterone receptors assayed simultaneously. The biological relevance of EGF-R in meningioma is discussed in this context.

Adult↗

PubMed1987

Estrogen and progestin receptor assay in fine needle aspirates of breast cancer: methodological aspects.

A methodology, originally built up in our laboratory, for the simultaneous determination of estrogen (ER) and progesterone (PR) receptors on small samples of tumor tissues, has been adapted to fine needle aspirates (FNA) of breast tumors. The method is based on a simultaneous incubation of aliquots of high-salt (0.4 M KCl) cytosols with tritiated estrogen and progestin tags. The mixture of receptor-bound ligands is isolated by dextran-coated charcoal and extracted by ethanol. The extracted ligands are separated quantitatively by HPLC and counted by liquid scintillation. FNA provides sufficient cellular material for ER and/or PR assay by single point (5 nM) dextran-coated charcoal (DCC) assay. FNA samples, being contaminated by blood, [3H] R 2858 and [3H] O 2058 are appropriate tags for ER and PR respectively, giving lowest non-specific binding. Sixty-five simultaneous estrogen and progestin receptor determinations on FNA at time of diagnosis were compared to the individual assays performed on the surgical sample obtained from the same patients a few weeks after diagnosis. The correlation between the 2 sets of determinations is excellent in 60 cases with sufficient FNA cellularity. This correlation validates the reliability of estrogen and progestin receptor determination on FNA in the majority of clinical cases.

Biopsy, Needle↗