Results of a cohort of 200 hormone-naïve consecutive patients with prostate cancer treated with iodine 125 permanent interstitial brachytherapy by the same multidisciplinary team.

PURPOSE: To report survival and morbidity of a cohort of 200 hormone-naïve consecutive patients with localized prostate cancer, treated by low-dose rate brachytherapy within the frame of multidisciplinary approach. PATIENTS AND METHODS: Between 2001 and 2011, 200 patients were treated by the same team with 125 iodine seeds: 167 low-risk and 33 intermediate risk according to the d'Amico classification; eligible patients had clinical stage T1/T2a-b, Gleason score 3+3 or 3+4, baseline prostate-specific antigen level below 15ng/mL, prostate volume less than 60cm(3). The median number of random biopsies was 12 (range 6-32) and the breakdown of positive cores was as follows: 1 (29%), 2 (35%), 3 or more (36%). Acute morbidity was assessed according to the Common Terminology Criteria for Adverse Events and late toxicity according to the EORTC/RTOG scale. Data were prospectively collected. RESULTS: The median follow-up was 69 months (range 16 to 135). The 5- and 10-year biochemical relapse free survivals were 95.6% (95% confidence interval [CI]: 91-98) and 89.7% (95% CI: 79.4-95.0). The 5-year and 10-year overall survival were respectively 96.4% (95% CI: 92-98.4) and 89.7% (95% CI: 80.8-94.6%) and the 10-year disease specific survival, 99.1% (95% CI: 93.0-99.9). The 5- and 10-year grade 3 acute toxicity cumulative rate were respectively 3.3% (95% CI: 1.4-6.6) and 4% (95% CI: 1.4-6.6) and the 5- and 10-year grades 3 cumulative late toxicity 2.5% (95% CI: 2.0-5.9) and 4% (95% CI: 2.0-5.9). CONCLUSION: Brachytherapy managed within the frame of a multidisciplinary approach - from diagnosis to evaluation - may offer optimized results with a reduced late toxicity rate, while remaining opened to dosimetry and technical improvements.

Lignification in transgenic poplars with extremely reduced caffeic acid O-methyltransferase activity.

Transgenic poplars (Populus tremula x Populus alba) were obtained by introduction of a sense homologous transgene encoding caffeic acid O-methyltransferase (COMT) under the control either of the cauliflower mosaic virus double 35S promoter or of the eucalyptus cinnamyl alcohol dehydrogenase promoter. Although these constructs conferred a moderate overexpression of COMT in some lines, a transgenic line with the double 35S promoter was found where COMT activity in woody tissues was close to zero due to a gene-silencing phenomenon. For the first time in COMT down-regulated trees, this alteration substantially reduced lignin level in 6-month-old trees (17% decrease). Lignin structure was found to be strongly altered, with a two times higher content in condensed bonds, an almost complete lack of syringyl units, and the incorporation of 5-hydroxyguaiacyl units to the most remarkable extent reported so far. Consistent with the higher cellulose content and with the higher condensation degree of the lignin, the impact of the transformation on the kraft-pulping performances of the poplar trees positively affected the pulp yield (10% relative increase), but made lignins less amenable to industrial degradations.

Structural alterations of lignins in transgenic poplars with depressed cinnamyl alcohol dehydrogenase or caffeic acid O-methyltransferase activity have an opposite impact on the efficiency of industrial kraft pulping

We evaluated lignin profiles and pulping performances of 2-year-old transgenic poplar (Populus tremula x Populus alba) lines severely altered in the expression of caffeic acid/5-hydroxyferulic acid O-methyltransferase (COMT) or cinnamyl alcohol dehydrogenase (CAD). Transgenic poplars with CAD or COMT antisense constructs showed growth similar to control trees. CAD down-regulated poplars displayed a red coloration mainly in the outer xylem. A 90% lower COMT activity did not change lignin content but dramatically increased the frequency of guaiacyl units and resistant biphenyl linkages in lignin. This alteration severely lowered the efficiency of kraft pulping. The Klason lignin level of CAD-transformed poplars was slightly lower than that of the control. Whereas CAD down-regulation did not change the frequency of labile ether bonds or guaiacyl units in lignin, it increased the proportion of syringaldehyde and diarylpropane structures and, more importantly with regard to kraft pulping, of free phenolic groups in lignin. In the most depressed line, ASCAD21, a substantially higher content in free phenolic units facilitated lignin solubilization and fragmentation during kraft pulping. These results point the way to genetic modification of lignin structure to improve wood quality for the pulp industry.

Red Xylem and Higher Lignin Extractability by Down-Regulating a Cinnamyl Alcohol Dehydrogenase in Poplar.

Cinnamyl alcohol dehydrogenase (CAD) catalyzes the last step in the biosynthesis of the lignin precursors, the monolignols. We have down-regulated CAD in transgenic poplar (Populus tremula X Populus alba) by both antisense and co-suppression strategies. Several antisense and sense CAD transgenic poplars had an approximately 70% reduced CAD activity that was associated with a red coloration of the xylem tissue. Neither the lignin amount nor the lignin monomeric composition (syringyl/guaiacyl) were significantly modified. However, phloroglucinol-HCl staining was different in the down-regulated CAD plants, suggesting changes in the number of aldehyde units in the lignin. Furthermore, the reactivity of the cell wall toward alkali treatment was altered: a lower amount of lignin was found in the insoluble, saponified residue and more lignin could be precipitated from the soluble alkali fraction. Moreover, large amounts of phenolic compounds, vanillin and especially syringaldehyde, were detected in the soluble alkali fraction of the CAD down-regulated poplars. Alkaline pulping experiments on 3-month-old trees showed a reduction of the kappa number without affecting the degree of cellulose degradation. These results indicate that reducing the CAD activity in trees might be a valuable strategy to optimize certain processes of the wood industry, especially those of the pulp and paper industry.