Phase II study of preoperative radiation plus concurrent daily tegafur-uracil (UFT) with leucovorin for locally advanced rectal cancer

<p>Abstract</p> <p>Background</p> <p>Considerable variation in intravenous 5-fluorouracil (5-FU) metabolism can occur due to the wide range of dihydropyrimidine dehydrogenase (DPD) enzyme activity, which can affect both tolerability and efficacy. The oral fluoropyrimidine tegafur-uracil (UFT) is an effective, well-tolerated and convenient alternative to intravenous 5-FU. We undertook this study in patients with locally advanced rectal cancer to evaluate the efficacy and tolerability of UFT with leucovorin (LV) and preoperative radiotherapy and to evaluate the utility and limitations of multicenter staging using pre- and post-chemoradiotherapy ultrasound. We also performed a validated pretherapy assessment of DPD activity and assessed its potential influence on the tolerability of UFT treatment.</p> <p>Methods</p> <p>This phase II study assessed preoperative UFT with LV and radiotherapy in 85 patients with locally advanced T3 rectal cancer. Patients with potentially resectable tumors received UFT (300 mg/m/²/day), LV (75 mg/day), and pelvic radiotherapy (1.8 Gy/day, 45 Gy total) 5 days/week for 5 weeks then surgery 4-6 weeks later. The primary endpoints included tumor downstaging and the pathologic complete response (pCR) rate.</p> <p>Results</p> <p>Most adverse events were mild to moderate in nature. Preoperative grade 3/4 adverse events included diarrhea (n = 18, 21%) and nausea/vomiting (n = 5, 6%). Two patients heterozygous for dihydropyrimidine dehydrogenase gene (<it>DPYD</it>) experienced early grade 4 neutropenia (variant IVS14+1G > A) and diarrhea (variant 2846A > T). Pretreatment ultrasound TNM staging was compared with postchemoradiotherapy pathology TN staging and a significant shift towards earlier TNM stages was observed (p < 0.001). The overall downstaging rate was 42% for primary tumors and 44% for lymph nodes. The pCR rate was 8%. The sensitivity and specificity of ultrasound for staging was poor. Anal sphincter function was preserved in 55 patients (65%). Overall and recurrence-free survival at 3 years was 86.1% and 66.7%, respectively. Adjuvant chemotherapy was administered to 36 node-positive patients (mean duration 118 days).</p> <p>Conclusion</p> <p>Preoperative chemoradiotherapy using UFT with LV plus radiotherapy was well tolerated and effective and represents a convenient alternative to 5-FU-based chemoradiotherapy for the treatment of resectable rectal cancer. Pretreatment detection of DPD deficiency should be performed to avoid severe adverse events.</p

Shrinkage and drainage in volcanic soil aggregates : a structural approach using air under vaccum drying kinetics and mercury porosimetry

International audienc

Fractionnement des argiles par ultracentrifugation en continu : évolution des illites en milieu podzollque / Clay fractionation by continuous flow uitracentrifugation : evolution of illites in a podzolic soil

A fractionation method of soil clays is described. The separation of the clay fraction into size classes (< 0. 1/µm ; 0. 1 -0.5 /µm ; 0.5 -2 µm) is made by repeated dispersion and ultracentrifugation with a Sharpies centrifuge. The fractionation quality depends on the dispersion quality of the clay suspension. The use of cation exchange resins (Na+ form) improves the dispersion. The method applied to a podzol developed on triassic sandstone gives evidence of accumulation of small clays (< 0. 1 µm) in the spodic horizons. This accumulation is certainly old and would result in clay illuviation that happened during the deposit of the colluvium along the slopes. During the podzolization phase, mixed-layer clay minerals (I — Sm) and smectites were formed from weathered and fragmented illites. The smectites tend to disapear from the eluvial A2 horizon : a part was translocated toward the Bh horizon, the greatest part of them being melted. The released aluminum was distributed in the spodic Bs horizon, where its hydroxi-polymerization occured. This provokes the formation of amorphous alumina, mixed silica-aluminous gels like allophane and hydroxi-interlayered smectite and vermiculite.Une méthode de fractionnement des argiles des sols est décrite. Elle repose sur l'utilisation d'une centrifugeuse (de type Sharpies) qui opère en flux continu et effectue une séparation selon la taille des particules argileuses élémentaires. La qualité du fractionnement est conditionnée par l'état de dispersion de la suspension argileuse : l'emploi de résines échangeuses d'ions (forme sodique) assure des conditions satisfaisantes de dispersion. La méthode appliquée à un podzol développé sur grès triasique met en évidence une accumulation d'argiles très fines (< 0, 1/µm) dans les horizons spodiques. Cette accumulation est certainement ancienne, et résulte d'un lessivage contemporain de la mise en place des matériaux sur les pentes. Bien que le processus ait pu être amorcé plus tôt, il semble certain qu'au cours de la podzolisation les illites qui accompagnent la kaolinite évoluent vers des interstratifiés I — Sm et des smectites, en même temps qu'elles se fragmentent. Dans l'horizon éluvial A2, les smectites tendent à disparaître : une partie est transférée vers l'horizon Bh, la majorité est dissoute. L'aluminium libéré se distribue dans l'horizon spodique Bs sous forme amorphe, coprécipite avec la silice pour donner naissance à des allophanes, et provoque l'hydroxyaluminisation des minéraux 2/1 expansibles, qui perdent leurs propriétés de gonflement.Rouiller James, Brethes Alain, Burtin Gérard, Guillet Bernard. Fractionnement des argiles par ultracentrifugation en continu : évolution des illites en milieu podzollque / Clay fractionation by continuous flow uitracentrifugation : evolution of illites in a podzolic soil. In: Sciences Géologiques. Bulletin, tome 37, n°4, 1984. Minéraux argileux. pp. 319-331

Root impact on the stability and types of microaggregates in silty soil under maize

We wished to assess the impact of maize roots on the stability, nature and formation of soil organomineral aggregates under field conditions. We sampled coarse-textured soil, cropped with maize for 3 years, and combined in situ study of the root system with evaluation of soil structural stability. We examined root morphology (i) on thin sections of still recognizable root tissues, and (ii) at the interfaces between roots and soil, using transmission electron microscopy (TEM) to differentiate between fine and coarse roots. Soil structural stability was evaluated in relation to a spatial gradient of increasing distance from the roots. For that we distinguished between soil adhering to roots and that not adhering in the rhizosphere, and soil between the rows of this crop, and used two methods of granulodensimetric soil fractionation involving different disaggregation strengths. We isolated and identified the organomineral associations in the soil fractions determining soil stability. We found that the roots at the soil–root interface generated stable aggregates of 2–20 mm size, which were much involved in the structural stability of the soil adhering to roots. We identified by TEM several types of organomineral associations that depended on the nature of the plant or microbial organic matter. The distribution of the different types of aggregates varied according to their positions in relation to the roots. We showed that humification of roots contributes significantly to the development of stable organomineral associations in the soil