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Biomedical subjects

P Van Houtte

Publications and source records attributed to P Van Houtte.

At least 19 recordsLinked to original sources
PubMed2006

[Adjuvant treatments of non-small cell lung cancer].

If surgery remains the cornerstone for the curative treatment of non-small cell lung cancer, failures are common especially for stage III disease and adjuvant treatment (chemotherapy or radiotherapy) may be justified. After the two meta-analyses, new trials have showed a moderate but significant benefit from cisplatin based chemotherapy. The role of radiotherapy is still controversial but from some clinical observations, a new trial using the modern radiation technology should address the question.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Electron backscatter diffraction on pearlite structures in steel.

Electron backscatter diffraction measurements were performed on a set of pearlitic steel samples after different heat treatments. The strengths and limitations of the technique with respect to the pearlite issue are presented. Interpretation of the obtained results confirmed that more than one pearlite colony may exist inside one ferrite nodule of nearly the same crystallographic orientation. It was also found that, in most cases, a misorientation of the order of several degrees exists between pearlite colonies within one ferrite nodule. Moreover, the ferrite matrix exhibits changes of crystallographic orientation inside colonies often accompanied by a network of low angle boundaries. The mean size of the ferrite nodule in the matrix was determined by means of electron backscatter diffraction. However, determination of the mean pearlite colony size was difficult and often impossible by means of both metallographic methods and electron backscatter diffraction measurements.

Journal Article↗
PubMed2005

[Radiation therapy of benign diseases. What's new eight years after?].

The authors present an update version of the indications for radiotherapy in the management of benign diseases. This is based on available randomized trials and recent international meetings. Validated indications remain the prevention of resected heterotopic bone ossifications, keloïds scars and pterygium and also treatment of arteriovenous malformations; the place of radiotherapy for malignant exophtalmia is more and more restricted. Randomized trials have demonstrated the efficacy of endobrachytherapy in the prevention of restenosis after angioplasty but the use of embedded stent has replaced this indication. Macular degeneration is no more an indication of radiotherapy. Quality requirements for radiotherapy are identical for benign or malignant indications.

Arteriovenous Malformations↗
PubMed2005

[Ovarian metastasis and lung adenocarcinoma: a case report].

Ovarian metastasis as first dissemination site of a lung adenocarcinoma has not been described in the literature. We report the case of a 61-year-old woman who had a pneumectomy for a centrally located lung adenocarcinoma, which was discovered on a routine chest X-Ray. During the follow-up, a Positron Emission Tomography (PET)-Scan showed a hypercaptation in the pelvic region. Abdominal CT-scan confirmed the presence of a mass which was compatible with a primary ovarian tumor. The patient underwent a hysterectomy and bilateral salpingo-oophorectomy. Pathology reported an adenocarcinoma. Immunohistochemical staining revealed cells expression for Thyroid Transcription Factor 1 (TTF-1), cytokeratin 7 (CK-7) and focally cytokeratin 20 (CK-20). Clinical course, pathological and immunohistochemical data concluded to the diagnosis of ovarian metastasis of the lung adenocarcinoma. In conclusion, in the differential diagnosis of an ovarian metastasis, clinicians should not forget the lung as primary site since epidemiologic data of lung cancer in women show progressive incidence.

Adenocarcinoma↗
PubMed2005

Interaction between estrogen receptor alpha, ionizing radiation and (anti-) estrogens in breast cancer cells.

PURPOSE: Estrogen receptor alpha (ERalpha) plays a major role in breast cancer development. It acts as ligand-inducible transcription factor which determines growth, survival and differentiation of breast cancer cells. The aim of this study is to evaluate the potential interference between radiotherapy and estrogen receptor responsiveness. Materials and methods. The effect of ionizing radiation was assessed on the estrogen receptor alpha status, growth (proliferation and apoptosis) and sensitivity of MCF-7 breast cancer cells to estrogenic (17beta-estradiol (E2)), selective estrogen receptor modulator (SERM) and anti-estrogenic compounds. Results. We have observed a ligand-independent decrease in ERalpha expression after radiation, resulting from a specific reduction in mRNA level and protein synthesis. This ERalpha disappearance occurred 72 h post-irradiation at 8 Gy and decreased the transcriptional activity in ERalpha of these cells. On the other hand, E2 impedes the growth inhibitory effects (essentially on proliferation) of ionizing radiation in MCF-7 cells, which potentially decreases radiosensitivity of these cells. This effect was totally blocked by SERM and anti-estrogenic treatments. Moreover, this growth effect of concurrent anti-estrogenic drugs and ionizing radiation appeared to be strongly synergistic. CONCLUSIONS: This study may increase general comprehension of ERalpha modulation by radiotherapy and improve adjuvant therapeutic approaches based on co-administration of radiation and endocrine therapy.

Analysis of Variance↗
PubMed2005

Visualization of grain subdivision by analysing the misorientations within a grain using electron backscatter diffraction.

The misorientation relative to the average orientation of a grain and the point-to-point relative misorientation along a line across a moderately cold deformed grain, calculated from an electron backscatter diffraction (EBSD) dataset, are analysed in detail by visualizing both the misorientation angle and the misorientation axis. The significance of monitoring the misorientation axis is illustrated by an example of a grain subdivided into a misorientation band structure. A new technique to visualize the subdivision structure by assigning colours to misorientations in such a way that the contrast is maximized within a grain is introduced and discussed. Furthermore, some methods for grain boundary reconstruction from EBSD datasets are compared with the map of the confidence index in order to provide a validation of the accuracy of these methods.

Journal Article↗
PubMed2005

[A new area for radiotherapy with favourable features].

Radiotherapy is a complex medical speciality involving technology research, biology research and clinical research. All these basic researches are performed in order to optimise the management of cancer treatment patients. The aim of the present review is to present radiotherapy as a moving speciality whatever the concerned section. It will be particularly described the new approaches in terms of technology but also clinical developments.

Humans↗
PubMed2004

[Biomodulation of transcriptional factor NF-kappa B by ionizing radiation].

NF-kappaB (Nuclear Factor-kappaB) was described for the first time in 1986 as a nuclear protein binding to the kappa immunoglobulin-light chain enhancer. Since then, NF-kappaB has emerged as an ubiquitous factor involved in the regulation of numerous important processes as diverse as immune and inflammatory responses, apoptosis and cell proliferation. These last two properties explain the implication of NF-kappaB in the tumorigenic process as well as the promise of a targeted therapeutic intervention. This review focuses on the current knowledge on NF-kappaB regulation and discusses the therapeutic potential of targeting NF-kappaB in cancer in particular during radiotherapy.

Antioxidants↗
PubMed2004

A phase III randomised study comparing two different dose-intensity regimens as induction chemotherapy followed by thoracic irradiation in patients with advanced locoregional non-small-cell lung cancer.

PURPOSE: The aim of this study was to determine the role of chemotherapy dose intensity in patients with initially unresectable non-metastatic non-small-cell lung cancer (NSCLC), with survival as primary end point, by testing two different regimens as induction chemotherapy followed by thoracic irradiation. PATIENTS AND METHODS: Patients had pathologically proven NSCLC, an initially unresectable non-metastatic tumour without homolateral malignant pleural effusion, no prior history of malignancy and had received no prior therapy. Treatment was randomised for chemotherapy between three courses of MIP (mitomycin C 6 mg/m2; ifosfamide 3 g/m2; cisplatin 50 mg/m2) or SuperMIP (mitomycin C 6 mg/m2; ifosfamide 4.5 g/m2; cisplatin 60 mg/m2, carboplatine 200 mg/m2), followed by chest irradiation (60 Gy; five times per week, for 6 weeks). If the tumour became resectable after chemotherapy, surgery was performed, followed by mediastinal irradiation. RESULTS: A total of 351 patients were eligible: 176 in the MIP arm and 175 in the SuperMIP arm, with 43% and 51% stages IIIA and IIIB, respectively. There was a significantly higher objective response rate with SuperMIP (46%) compared with MIP (35%) (P=0.03) [95% confidence interval (CI) for the difference between the response rates, 1% to 22%]. After induction chemotherapy, surgery was performed in 54 (15%) patients (27 per arm) and chest irradiation in 203 (57%) patients (102 in the MIP arm and 101 in the SuperMIP). In terms of survival, there was no statistically significant difference between the two study arms (P=0.16), with median survival times of, for MIP and SuperMIP, respectively, 12.5 (95% CI 10.1-14.9) and 11.2 (95% CI 9.7-12.8) months. Haematological toxicity and dosage reductions were higher with SuperMIP, which was nevertheless associated with a significantly increased absolute dose intensity. CONCLUSIONS: High dose-intensity induction chemotherapy does not improve survival in initially unresectable non metastatic NSCLC.

Adult↗
PubMed2004

Cysteine but not glutathione modulates the radiosensitivity of human melanoma cells by affecting both survival and DNA damage.

Glutathione (GSH) and its precursor cysteine (Cys) are both known to react within any cells with oxidative species and thus play an important role in cellular defense mechanisms against oxidative stress. In melanocytes, these are also important precursors of melanogenesis by reacting non-enzymatically with l-dopaquinone to form the sulfur-containing pheomelanin. Our aim was to assess pigment role in the cellular radioprotection mechanism using a human melanoma cell model of mixed-type melanin under GSH depletion to obtain a radiosensitizing effect. The latter has been achieved either by Cys deprivation or GSH specific depletion. We first compared cell survival of Cys-deprived and GSH-depleted cells vs. control cells. Cys deprivation was achieved by decreasing Cys concentration in the culture medium for 24 h. In this condition, no toxicity was observed, Cys and GSH levels decreased, melanogenesis switched to a higher eumelanin synthesis and cells were significantly more resistant to 10-Gy dose of ionizing radiations than untreated cells. Glutathione depletion was achieved with the gamma-glutamylcysteine synthetase inhibitor buthionine-S-sulfoximine (BSO) for 24 h at 50 microM, a concentration yielding no toxicity. In this condition, intracellular GSH level decreased but no change in pigmentation was observed and cells were slightly but significantly more sensitive to radiation than the control. We then compared DNA radio-induced damages by Comet assay in control cells, cells treated as above and cells with stimulated pigmentation by increasing Tyr concentration in the medium. Our results showed that, when intracellular eumelanin content increased, DNA damage decreased. By contrast, DNA damage increased in cells treated with BSO alone. It is concluded that increasing the intracellular eumelanin content by the melanin precursor Tyr or by favoring the Pheo- to Eumelanin switch, compensates for the loss of the two intracellular radioprotectors that are GSH and Cys.

Buthionine Sulfoximine↗
PubMed2002

[Locally advanced non-small-cell bronchial cancer: role of exclusive chemoradiotherapy].

Lung cancer is the most frequent form of malignant tumours. The prognosis is poor with a 5-year cure rate which increased from approximately 6% in the sixties to only 15% in the nineties. Surgery remains the reference treatment but only a small minority of patients (about 25%) present with operable disease. The post-surgical 5-year survival is only 25%, providing the rationale for the current research on adjuvant treatments for control of both local and metastatic disease. In that context, the combination of radiotherapy and chemotherapy, commonly referred to as chemo-radiotherapy, has assumed considerable importance: either exclusively in inoperable patients (inoperable tumour or patients inoperable for medical reasons), or pre-operatively. This article reviews the results of the pivotal definitive chemoradiotherapy studies in non-metastatic non-small-cell lung cancer. With exclusive chemoradiation, the concomitant scheme seems to be the most favourable, results issued from randomised studies are expected to confirm that point. An increased toxicity is observed, and the advent of conformal therapy may allow another survival gain. Optimal treatments integration will be necessary.

Antineoplastic Agents↗
PubMed2001

Effect of low dose irradiation on estrogen receptor level in MCF-7 breast cancer cells.

Exposure of MCF-7 cells to single and/or repeated low gamma-ray doses (0.5 to 8 Gy) resulted in a decrease in the capacity of these cells to concentrate tritiated estradiol ([3H]E2) (reduction of the number of binding sites). The decrease in the [3H]E2-binding capacity was higher than the survival rate, indicating that it could not be ascribed to cell death. Moreover, such low irradiation doses failed to similarly affect the specific incorporation of [3H]ORG 2058, even when the progesterone receptor was induced by E2, a finding that rejects the hypothesis of a nonspecific effect on all steroid hormone receptors. This loss of [3H]E2 binding was reflected by the elimination of the estrogen receptor alpha (ER) when the latter was assessed by immunocytochemistry. However, additional immunochemical studies (Western blot data) performed on cell extracts under denaturing conditions failed to show any similar elimination of the ER peptide, suggesting that the loss of E2-binding capacity would be relevant to subtle changes in the ER structure and/or ER-associated proteins. The loss of binding capacity, produced by a 3-Gy irradiation, failed to decrease the sensitivity of the cells to E2, since progesterone receptor induction and growth stimulation were maintained. Insufficient ER diminution may explain this observation.

Binding Sites↗
PubMed2001

[Pigmented villonodular synovitis: apropos of 3 cases].

Three cases of pigmented villonodular synovitis treated in recent years are described. One case presents a malignant transformation and raises the question of the benign character of these lesions. The therapeutic options are considered as well as the need for a larger series of patients to define therapeutic strategy.

Adult↗
PubMed2001

[Gross tumor volume and clinical target volume in radiotherapy: lung cancer].

Radiotherapy plays a major role as a curative treatment of various stages non-small cell lung cancers (NSCLC): as an exclusive treatment in curative attempt for patients with unresectable stages I and II; as a preoperative treatment, which is often associated with chemotherapy, for patients with surgically stage IIIA NSCLC in clinical trials; in association with chemotherapy for unresectable stages IIIA and IIIB patients. Currently, three-dimensional conformal radiotherapy allows for some dose escalation, increasing radiation quality. However, the high inherent conformality of this radiotherapy technique requires a rigorous approach and an optimal quality of the preparation throughout the treatment procedure and specifically of the accurate definition of the safety margins (GTV, CTV...). Different questions remain specific to lung cancers: 1) Despite the absence of randomized trials, the irradiated lymph nodes volume should be only, for the majority of the authors, the visible macroscopically involved lymph nodal regions. However, local control remains low and solid arguments suggest the poor local control is due to an insufficient delivered dose. Therefore the goal of radiotherapy, in this particular location, is to improve local control by increasing the dose until the maximum normal tissue tolerance is achieved, which essentially depends on the dose to the organs at risk (OAR) and specifically for the lung, the esophagus and the spinal cord. For this reason, the irradiated volume should be as tiny as possible, leading to not including the macroscopically uninvolved lymph nodes regions in prophylactic view in the target volume; 2) The lung is one of the rare organs with extensive motion within the body, making lung tumors difficult to treat. This particular point is not specifically considered in the GTV and CTV definitions but it is important enough to be noted; 3) When radiation therapy starts after a good response to chemotherapy, the residual tumoral volume should be defined as the target volume in place of the initial tumor volume. These different elements are discussed in this paper.

Carcinoma, Non-Small-Cell Lung↗
PubMed2001

[Benign diseases in radiotherapy: a practice survey in Belgium. Peer review of radiotherapy in Belgium].

In 1996 and 2000, a survey of radiation practice in Belgium was performed by sending a questionnaire to the different centers asking their opinion and number of patients treated. There was a great similarity between the two surveys both for indications and total number of patients irradiated. For the most common indications (prevention of cheloids, heterotopic bone formation, hyperthyroidy ophthalmopathy), there was a trend to use similar radiation technique following recent publications. In contrast, if the number of cases of macular degeneration is declining, the prevention of vessels restenosis is becoming more and more an indication.

Belgium↗