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M Péoc'h

Publications and source records attributed to M Péoc'h.

16 recordsLinked to original sources
PubMed2005

[Development of an experimental model for the study of the effects of cryotherapy on lung tumours].

UNLABELLED: Adenocarcinomas are today the most frequent lung cancers. They are mainly treated by surgery or by chemotherapy, but for the most advanced stages a local cryotherapy can be proposed as a palliative option for bronchial desobstruction. AIM OF THE STUDY: The aim of this work was to establish an experimental model to study in vivo the biological effects of this technique to propose it as a neoadjuvant treatment. MATERIALS AND METHODS: A xenograft system was used: cells from the A549 cell line were injected subcutaneously into SCID mice. Tumour nodes could be treated after seven weeks. The histological study showed that these tumours faithfully reproduced the morphological features of adenocarcinoma, and developed an intratumoral neovascularization. Two protocols of cryotherapy (1 vs 3 cycles of freezing) were performed and the induction of apoptosis was analyzed by immunohistochemical staining of cleaved caspase-3. RESULTS: The basal expression of cleaved caspase-3 in untreated tumours (23%) increased after cryotherapy. The increase was maximal eight hours after treatment (up to 47% of positive cells) and was less important with the first protocol, suggesting a lesser efficiency in the induction of apoptosis. CONCLUSION: The establishment of this model, which is faithful to physiological features, allowed us to demonstrate in vivo time and dose-dependent effects of cryotherapy.

Adenocarcinoma↗
PubMed2004

In vivo assessment of tumoral angiogenesis.

Vessel size imaging (VSI) for brain tumor characterization was evaluated and the vessel size index measured by MRI (VSIMRI) was correlated with VSI obtained by histology (VSIhisto). Blood volume (BV) and VSI maps were obtained on 12 rats by simultaneous measurements of R2* and R2, before and after the injection of a macromolecular contrast agent, AMI-227. Immunostaining of collagen IV in vessels was performed. An expression was derived for evaluating VSI from stereologic measurements on histology data (VSIhisto). On BV and VSI images obtained from large-size tumors (n = 9), three regions could be distinguished and correlated well with histological sections: a high BV region surrounding the tumor, a necrotic area where BV is very low, and a viable tumor tissue region showing lower BV but higher VSI than the normal rat cortex, with the presence of larger vessels. The quantitative analysis showed a good correlation (Spearman rank's rho = 0.74) between VSIhisto and VSIMRI with a linear regression coefficient of 1.17. The good correlation coefficient supports VSI imaging as a quantitative method for tumor vasculature characterization.

Animals↗
PubMed2003

Misregulation of histone acetylation in Sertoli cell-only syndrome and testicular cancer.

In many species, including humans, chromatin remodelling during spermiogenesis is initiated with a marked increase in histone acetylation in elongating spermatids. We have investigated whether this process is disturbed when spermatogenesis is defective or in human testicular tumours. For this purpose, the presence of highly acetylated histone H4 was detected on testicular sections from men with a severe impairment of spermatogenesis of several origins, as well as in different types of testicular tumours. In most tubules devoid of germinal cells (including SCO, Sertoli cell only syndromes) or lacking spermatocytes and spermatids, the Sertoli cells' nuclei showed a global increase in histone H4 acetylation. A similar observation was made in the peritumoral seminiferous tubules of testicular tumour tissues, whenever they were lacking germinal cells, with carcinoma in situ (CIS) cells being hypoacetylated. The global hyperacetylation of elongating spermatids during spermatogenesis could be part of an intercellular signalling pathway involving Sertoli cells and germinal cells, which could be disturbed in cases of severe spermatogenesis impairment, as well as in tubes surrounding germ cells in testicular tumours.

Acetylation↗
PubMed2000

Relationships between cardiovascular remodelling and the pulse pressure in never treated hypertension.

The role of pulse pressure (PP) in cardiovascular remodelling was studied in 61 never treated hypertensive subjects who were selected on the criteria of ambulatory blood pressure (BP) monitoring (mean BP over 24 h: 147 +/- 14/96 +/- 10 mm Hg). Echocardiography and carotid ultrasonography were performed and the vascular images analysed using a specific automatic measuring program. Thirty percent of subjects had left ventricular hypertrophy (LVH). Left ventricular mass index (LVMI) was related to the clinic (r = 0.35) and ambulatory (r = 0.41 over 24 h, r = 0.38 daytime and r = 0.42 night-time) PP and to the systolic BP. PP was higher when there was LVH. Vascular thickening was found in 6.6% of subjects (carotid intima-media thickness (IMT) >/=1.0 mm). Among the BP parameters, IMT and cross-sectional area (CSA) were related only to the clinic PP (r = 0.27, r = 0.29 respectively) and to the ambulatory PP (over 24 h: r= 0.29, r = 0.28; daytime: r = 0.22, r = 0.23; night-time: r = 0.32, r = 0.30). In men, the relationship between CSA and PP (clinic and over 24 h) was independent of age. A total of 16.7% of subjects with LVH had intima-media thickening in contrast to 2.3% in the group without LVH. LVMI was related to the CSA (r = 0.37) and to the IMT (r = 0.31). However, after multivariate analysis taking into account the PP, relationships between IMT or CSA and LVMI disappeared. Our data showed that the PP was the most important BP parameter in the development of cardiac and arterial remodelling in hypertension. Journal of Human Hypertension (2000) 14, 23-30.

Blood Pressure↗
PubMed2000

Silicone lymphadenopathy mimicking a lymphoma in a patient with a metatarsophalangeal joint prosthesis.

With lymph node enlargement, the possibility of a malignant process such as metastatic carcinoma or lymphoma needs to be excluded. This report describes a 47 year old woman with inguinal lymph node enlargement initially suspicious for lymphoma. Fine needle aspiration findings favoured reactive hyperplasia, but a malignant process could not be excluded. The final histological diagnosis was a foreign body granulomatous inflammatory response as a result of regionally disseminated silicone particles from an over looked metatarsophalangeal joint prosthesis. Because of the large number of joint prostheses world wide, it should be kept in mind that migration of wear particles can create granulomatous inflammation and node enlargement.

Diagnosis, Differential↗
PubMed1999

Use of T(2)-weighted susceptibility contrast MRI for mapping the blood volume in the glioma-bearing rat brain.

The aim of this work was to evaluate the potential of T(2)-weighted, steady-state susceptibility-enhanced contrast magnetic resonance imaging (MRI), to characterize brain tumor heterogeneity and tumor vascularization. In vivo T(2)-weighted MRI experiments were carried out on normal rats (n = 11) and rats bearing C6 glioma (n = 17), before and after the injection of a remanent superparamagnetic contrast agent. The DeltaR(2) variations of the transverse relaxation rate due to the injection of the contrast agent were used to generate relative cerebral blood volume (CBV) maps. Contrast enhancement of the tumor was shown to reflect tissue vascularization rather than leakage of the blood-brain barrier. The quantitative results clearly show the heterogeneity of tumor vascularization and reveal a high vessel density in the peripheral area (CBV(per) approximately 17.2 +/- 2.3 sec(-1)) and a low vessel density in the central area of the tumor (CBV(cen) approximately 2.5 +/- 0.5 sec(-1)). Magn Reson Med 42:754-761, 1999.

Animals↗
PubMed1999

Deletion 7q in B-cell low-grade lymphoid malignancies: a cytogenetic/fluorescence in situ hybridization and immunopathologic study.

Ten cases presenting a simple karyotype and del(7q) as a primary event were selected out of 353 patients referred as B-cell low-grade malignant lymphoproliferative disorders. Chromosome 7-specific painting probes confirmed the deletion that was tentatively assigned to bands q31q35. Chromosome 7 was involved in an interstitial deletion in seven cases, in an unbalanced translocation in two cases, and in a ring chromosome in one case. Common clinical/hematological features included advanced age, marked splenomegaly, and peripheral blood monoclonal IgM(D) lymphocytosis. Regardless of morphologic entity, most cases shared lymphoplasmacytoid features. Deletion 7q may delineate a variety of low-grade B-cell lymphoid disorders characterized by a common clinical history and immunopathologic similarities. The cytogenetic pattern and the ongoing work on molecular mapping of this deletion suggest that the loss of a putative tumor-supressor gene at 7q31q32 may constitute an early event in their pathogenesis.

Age Factors↗
PubMed1998

Foreign body histiocytosis reaction after hip replacement with concomitant metastatic adenocarcinoma in the same lymph node.

Infiltration of regional lymph nodes by macrophages has been shown after total joint arthroplasty. These pelvic lymph nodes were obtained most often from patients during staging procedures for carcinoma and may be a diagnostic pitfall in the frozen section diagnosis of nodal metastasis. We report an unusual case of association in the same lymph node between histiocytosis and prostatic carcinoma metastasis. Histiocytosis was caused by wear debris from two different prostheses. Inductively coupled plasma mass spectrometry verified this diagnosis.

Adenocarcinoma↗
PubMed1998

Desmoplastic small round cell tumor: RT-PCR analysis and immunohistochemical detection of the Wilm's tumor gene WT1.

Desmoplastic small round cell tumor is an aggressive neoplasm first described in 1991. Recently, a reciprocal translocation t(11;22)(p13;q12) has been characterized by conventional cytogenetic studies and molecular analysis. This translocation involves the Ewing's sarcoma gene on chromosome 22 and the Wilms' tumor gene WT1 on chromosome 11. The chimeric transcript corresponding to the fusion gene could be detected by the reverse transcriptase-polymerase chain reaction (RT-PCR). Using an anti-WT1 antibody, the WT1 part of the putative chimeric protein could be recognized by immunohistochemistry. We describe two well-characterized cases of intraabdominal desmoplastic small round cell tumor in two male patients aged 14 and 28 with both RT-PCR analysis and immunostaining for WT1. In this report, we insist on the necessity to increase the RT-PCR analysis in DSRCT in order to obtain a precise differential diagnosis. In addition, WT1 immunostaining may serve as a useful diagnostic marker for DSRCT.

Abdominal Neoplasms↗
PubMedDate not supplied

Quantification and distribution of neovascularization following microinjection of C6 glioma cells in rat brain.

BACKGROUND: It has been suggested that the switch to an angiogenic phenotype can separate the development of a tumor into two stages: the prevascular phase and the vascular phase. The purpose of the present work is to demonstrate the existence of an angiogenic switch in a longitudinal study of a brain tumor model during tumor growth by means of microvessel density measurements. MATERIALS AND METHODS: The study was performed on 32 rats bearing C6 glioma. At different stages of tumor growth, the histological aspects were described and sections were immunostained for factor VIII-related antigen in order to highlight microvessel endothelial cells. Microvessels were counted at 400 magnification for different areas (central non necrotic area, peripheral area, contralateral grey and white matter area), using image analysis software. RESULTS: Vessel density was significantly higher at the tumor-brain interface than in the center of the tumor or in the contralateral cortex. The vessel density remains stable in the tumor during the first 3 weeks after cell implantation, after which a clear increase of vessel density can be observed. CONCLUSION: The present study demonstrates the presence of an angiogenic switch which is concomitant with the development of necrosis and pseudopalisading pattern.

Animals↗