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RADIOTHERAPY OF ADULT NODAL NON HODGKIN'S LYMPHOMA: The role of radiotherapy in the treatment of nodal non-Hodgkin's lymphoma has been modified by the introduction of efficient chemotherapy and the development of different pathological classifications. INTERMEDIATE GRADE OR HIGH GRADE LYMPHOMA: The recommended treatment of early-stage aggressive lymphomas is primarily a combination chemotherapy. The interest of adjuvant radiotherapy remains unclear and has to be established through large prospective trials. If radiation therapy has to be delivered, the historical results of exclusive radiation therapy showed that involved-fields and a dose of 35-40 Gy (daily fraction of 1.8 Gy, 5 days a week) are the optimal schedule. The interest of radiotherapy in the treatment of advanced-stage aggressive lymphoma is yet to be proven. Further studies had to stratify localized stages according to the factors of the International Prognostic Index. LOW-GRADE LYMPHOMA: For early-stage low-grade lymphoma, radiotherapy remains the standard treatment. However, the appropriate technique to use is controversial. Involved-field irradiation at a dose of 35 Gy seems to be the optimal schedule, providing a 10-year disease-free survival rate of 50% and no major toxicity. There is no standard indication of radiotherapy in the treatment advanced-stage low-grade lymphoma. RARE AND NEW ENTITY: For "new" nodal lymphoma's types, the indication of radiotherapy cannot be established (mantle-zone lymphoma, marginal zone B-cell lymphoma) or must take into account the natural history (Burkitt's lymphoma, peripheral T-cell lymphoma) and the sensibility to others therapeutic methods.

The stress-strain relations derived from the sliding link model of chain entanglement proposed by Ball et al. (Polymer 1981, 22, 1010) are compared with experimental results. There is good agreement with Ogden's empirical treatment of several results obtained previously from general pure strain tests on rubber vulcanizates. New uniaxial data for random polyisoprene networks at various stages from the gel point indicate that a significant fraction of trapped entanglements does not behave as the sliding links of the model but gives the same contribution to the stress as the chemical cross-links.

Photoacoustic spectroscopy was applied to study the energetics and the kinetics of the slow intermediates of the bacteriorhodopsin photocycle. An analysis of the modulation frequency dependence of the photoacoustic signal allowed us to estimate the enthalpy changes and the kinetic parameters associated with those intermediates. The effects of pH, salt concentration, and protein aggregation were studied. Three photoacoustic transitions were found. The two low frequency transitions were attributed to O660 and M412, respectively. The third transition was interpreted as resulting from a protein conformational change undetected spectrophotometrically. The frequency spectra were simulated between 5 and 180 Hz at pH's 5.1, 7.0, and 8.9 assuming a branching in the bacteriorhodopsin photocycle at the M412 level. The enthalpy changes associated with M412 and O660 were computed and compared with the experimental values.

Resume On analyse les proprietes dynamiques et la relaxation de vulcanisats de caoutchouc naturel, de cis -polybutadiene et d'un copolymere butadiene (76,5)-styrene (23,5) en vue de determiner l'influence de certains parametres structuraux sur la forme et la position le long des echelles de temps des fonctions rheologiques caracterisant leur viscoelasticite. La persistance des pertes d'energie a basses frequences et le haut niveau correspondant de la distribution des temps de relaxation sont d'autant plus marques que ces reseaux polymeriques sont moins retifies ou contiennent davantage de noir de carbone HAF. On propose d'interpreter cette anomalie, sans doute etroitement apparentee au “plateau viscoelastique” des polymeres lineaires, a l'aide d'une extension de la theorie de Rouse, elaboree pour les polymeres en masse ou en solution concentree.