Role of endothelium in radiation-induced normal tissue damages; Role de l’endothelium dans les dommages radio-induits aux tissus sains. The goal of radiation therapy is to deliver enough ionising radiation to destroy cancer cells without exceeding the level that the surrounding healthy cells can tolerate.
Unfortunately, radiation-induced normal tissue injury is still a dose limiting factor in the treatment of cancer with radiotherapy. Spectroscoie endothelium is known to play a critical role in radiation-induced injury.
Our work shows that endothelial cells promote vascular smooth muscle cell proliferation, migration and fibro-genic phenotype after irradiation. Moreover, we demonstrate for the first time the importance of PAI-1 in radiation-induced normal tissue damage suggesting that PAI-1 may represent a molecular target to limit injury following radiotherapy.
Critical study of some soft-tissue equivalent material. Clurs to spectrodcopie of 1 keV to 14 MeV; Etude critique de quelques materiaux equivalents aux tissus mous. Sensibilite aux neutrons de 1 keV a 14 MeV. Centre d’ Etudes Nucleaires. Authors have studied the elastic and inelastic reactions on various elements contribution to kerma in standard soft tissue and as a function of neutron energy from 1 keV to 14 MeV the ratio of kerma in tissue equivalent material to kerma in soft tissue.
The results of calculations are made spectroscopid materials without hydrogen in view to state exactly their coyrs sensitivity and for the following hydrogenous materials: Rossi and Failla plastic, MixD, pure polyethylene and a new CEA tissue equivalent a magnesium fluoride and polyethylene compound.
Les materiaux etudies sont des materiaux sans hydrogene afin de preciser leur sensibilite aux neutrons et les materiaux hydrogenes suivants: Les resultats pour les df sont egalement rappeles. Open-air ionisation chambers with walls of soft-tissue equivalent material for measuring photon doses; Chambres d’ionisation d’ambiance a parois en materiau equivalent aux tissus mous pour la mesure des doses absorbees dues aux photons. The ionisation chambers presented in this report constitute a contribution to research into methods of carrying out correct determinations in the field of health physics.
The use of a mixture of teflon containing Furthermore since this material does not contain hydrogen, the chamber has a sensitivity to neutrons which is much less than other chambers in current use. Finally the shape of these chambers has been studied with a view to obtaining a satisfactory measurement from the isotropy point of view; for example for gamma radiation of 27 keV, the 3 litre chamber is isotropic to within 10 per cent over degrees, and the spectrosscopie litre chamber is isotropic to within 10 per cent over degrees; for 1.
This report presents the measurements carried out with these chambers as well as the results obtained. These results are then compared to those obtained with other chambers currently used in the field of health physics.
L’utilisation d’un melange de teflon charge a Directory of Open Access Journals Sweden. Full Text Available Sains Islam sampai saat ini masih terkungkung dalam lingkaran pseudoscience, atau masih pada taraf model justifikasi Bucaillian.
Sebagai bangunan ss3, sains Islam tentu memiliki basis filosofis.
Prof. Hassan Chaib
Tulisan ini berupaya mengkaji sains Islam dalam perspektif filsafat ilmu. Dalam perspektif ini, keilmiahan bangunan keilmuan ditentukan oleh ketepatan penggunaan teori dan metodologinya, tanpa mengabaikan sisi sosiologis-historis maupun sisi teologis-metafisis. Jika yang pertama merupakan basis logis dan objektifitas sainslalu yang kedua merupakan aspek kemanusiaan dari sainsmaka yang ketiga adalah basis keyakinan, keimanan, dan keberagamaan dari sains.
Dengan ketiga elemen penting tersebut, Sains Islam sebagai sains berbasis agama Islam bisa menjadi ilmiah. Dengan begitu, Sains Islam akan menghasilkan temuan-temuan baru, teori baru, metodologi baru, konteks baru, dan seterusnya.
Tanpa upaya itu, image pseudosains dan justifikasi Bucaillian akan sulit hilang dari bangunan keilmuan Sains Islam. Factors of late radiosensitivity of normal tissues; Facteurs de radiosensibilite tardive des tissus sains.
The impact of curative radiotherapy depends mainly on the total dose delivered homogeneously in the targeted volume. Nevertheless, the dose delivered to the surrounding healthy tissues may reduce the therapeutic ratio of many radiation treatments. Two different side effects acute and late can occur during and after radiotherapy.
Of particular interest are the radiation-induced sequelae due to their irreversibility and the potential impact on daily quality of life. In a same population treated in one centre with the same technique, it appears that individual radiosensitivity clearly exists.
In the hypothesis that genetic is involved in this area of research, lymphocytes seem to be the tissue of choice due to easy accessibility. Recently, low percentage of CD4 and CD8 lymphocyte apoptosis were shown to be correlated with high grade of sequelae. On-going studies are being analyzing the entire genome using a Genome-wide association study GWAS analysis.
Reirradiation of normal tissues: Preclinical radiobiological data; Reirradiation des tissus sains: Reirradiation represent an unfrequent particular clinical situation. There is a relatively limited amount of preclinical data available to date and clinicians should cautiously perform re-irradiations in selected indications. This review summarizes the experimental data available on reirradiation of normal tissues, the consequences on early and late toxicities as well as the intrinsic limitations of these models.
Normal tissue tolerance to external beam radiation therapy: Skin; Dose de tolerance des tissus sains: Acute skin toxicity is frequent during radiation therapy and can lead to temporary arrest of the treatment. Chronic toxicity can occur and conduct to cosmetic problems. Alopecia is the most frequent toxicity concerning hair and is most of the time reversible. Several factors linked to patients influence skin toxicity, such as under-nutrition, old age, obesity, smoking, skin diseases, autoimmune diseases, failure of DNA reparation.
Skin, hair and nail toxicities depend also on radiation schedule. Acute toxicity is greater when dose per fraction increases.
Chronic and acute toxicities are more often when total dose increases. Under 45 Gy, the risk of severe skin toxicity is low, and begins above 50 Gy.
Skin toxicity depends also on the duration of radiotherapy and split course schedules are associated with less toxicities. Irradiation surface seems to influence skin toxicity but interaction is more complex.
Reirradiation is often feasible in case of cancer recurrence but with a risk of grade toxicity above all in head and neck cancer. Permanent alopecia is correlated with the follicle dose. Modern techniques of radiation therapy allow to spare skin. Cardiac structures; Dose de tolerance des tissus sains: Radiation thoracic tumors may be associated with cardiac toxicity because of the central position of the heart in the thorax.
The present review aims to describe the cardiotoxicity during radiotherapy of different tumor sites most associated with this complication and the risk factors of cardiotoxicity during radiation therapy. Medline literature searches were performed using the following cardiac – heart – radiotherapy – toxicity – cardiotoxicity – breast cancer – lymphoma.
Cardiac toxicity after breast cancer and mediastinal lymphoma is the most reported radiation-induced complication. The most frequent clinical complications are pericarditis, congestive heart failure, and heart infarction.
These events are mostly asymptomatic. Thus clinicians have to give particular attention to these complications. Anthracycline treatment is a major risk factor for additional cardiotoxicity during radiotherapy with a synergistic effect. Correction of cardiovascular risk is an important point of the prevention of heart complications. Total dose delivered to the planned target volume PTVthe dose per fraction and the irradiated volume were correlated to the risk of cardiotoxicity.
Maximum heart distance maximal thickness of heart irradiated must be less than 1 cm during irradiation of breast cancer. Modern irradiation techniques seem to be associated with a limited risk of heart complication. The use of anthracycline, other cardio-toxic chemotherapies and targeted therapies should incite for great caution by performing a careful treatment planning and optimisation. Ovaries; Tolerance a l’irradiation des tissus sains: Clinical situations requiring protections of ovaries are mainly paediatric irradiations and pre-menopausal pelvic irradiations.
The main complication of ovarian irradiation is the induced castration. Ovaries are extremely radiosensitive organs with strong interpersonal variations.
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The specroscopie effect of irradiation depends mainly on two factors: The surgical technique of ovarian transposition allows to minimize the dose received by ovaries by taking them away, out of irradiation fields; the aim is to spectrowcopie them from the volume receiving 5 Gy or more, and if possible from those receiving 2 Gy.
This technique becomes integrated into a multidisciplinary approach of conservation of fertility for patients exposed to other cytotoxic treatments. Thyroid; Dose de tolerance des tissus sains: The thyroid is the most developed endocrine gland of the body. Due to its anatomical location, it may be exposed to ionizing radiation in external radiotherapy involving head and neck.
This review aims to describe the thyroid radiation disorders, probably under-reported in the literature, their risk factors and follow-up procedures. The functional changes after external beam radiation consists mainly of late effects occurring beyond 6 months, and are represented by the clinical and subclinical hypothyroidism.
Hyperthyroidism and auto-immune manifestations have been described in a lesser proportion. The morphological changes consist of benign lesions, primarily adenomas, and malignant lesions, the most feared and which incidence is 0. The onset of hypothyroidism depends of the total dose delivered to the gland, and the irradiated.
aux tissus sains: Topics by
Modern techniques of conformal radiotherapy with modulated intensity could improve the preservation of the thyroid, at the expense of the increase specyroscopie low doses and the theoretical risk of secondary cancers. Full Text Available Penulisan artikel ini bertujuan untuk memberikan format pengembangan intrumen penilaian keterampilan proses sains SD yang masih menjadi problematika untuk menentukan pengembangan instrumen.
Di samping itu, artikel ini ditulis untuk mengetahui karakteristik dan beberpa prosedur pelaksanaan penilaian proses sains SD dengan memberikan format pengembangan instrumen penialaian proses sains yang meliputi penyusunan rencana penelitian, penyusunan kisi-kisi, pembuatan soal sampai pada penganalisian butir soal.
Konsep dasar penilaian yang perlu ditekankan adalah keefektivan instrumen penilaian, yang terdiri dari tiga unsur utama yakni valid validity, reliabel reliability, dan praktis practicality. Berdasarkan tujuan dan perbedaan waktu pelaksanaanya, terdapat tiga jenis bentuk penilaian proses sains pada siswa Sekolah Dasar: Penilaian Diagnostik, Psectroscopie formatif dan Penilaian sumatif. Tes akan dianalisis secara kualitatif baik dari segi materi, konstruksi maupun bahasa.
Analisis secara kuantitatif dengan pendekatan teori tes klasik yakni dengan Iteman dan analisis secara kuantitatif menggunakan pendekatan teori tes modern yakni program Bigstep. Full Text Available AbstractThis study aimed to describe the profile of scientific reasoning and the argumentation skill of students from science and non-science.
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