Leaf chlorophyll fluorescence and reflectance of oakleaf lettuce exposed to metal and metal(oid) oxide nanoparticles.

BACKGROUND: Most nanoparticles (NPs) have a significant impact on the structure and function of the plant photosynthetic apparatus. However, their spectrum of action varies significantly, from beneficial stimulation to toxicity, depending on the type of NPs, the concentration used and plant genotypic diversity. Photosynthetic performance can be assessed through chlorophyll a fluorescence (ChlF) measurements. These data allow to indirectly obtain detailed information about primary light reactions, thylakoid electron transport reactions, dark enzymatic stroma reactions, slow regulatory processes, processes at the pigment level. It makes possible, together with leaf reflectance performance, to evaluate photosynthesis sensitivity to stress stimuli. RESULTS: We investigated effects of different metal and metal(oid) oxide nanoparticles on photosynthesis of oakleaf lettuce seedlings by monitoring the chlorophyll a fluorescence light radiation and reflectance from the leaves. Observations of ChlF parameters and changes in leaf morphology were carried out for 9 days in two-day intervals. Spectrophotometric studies were performed at 9th day. Suspensions of NPs with the following concentrations were used: 6% TiO2, SiO2; 3% CeO2, SnO2, Fe2O3; 0.004% (40 ppm) Ag; 0.002% (20 ppm) Au. Nanoparticles were applied directly on the leaves which caused small symptoms of chlorosis, necrosis and leaf veins deformation, but the plants fully recovered to the initial morphological state at 9th day. Leaf reflectance analysis showed an increase in FRI for SiO2-NPs and CeO2-NPs treatments and ARI2 for Fe2O3, however, WBI and PRI coefficients for the latter nanoparticle were lower than in control. Chlorophyll a fluorescence parameters have changed due to NPs treatment. Fe2O3-NPs caused an increase in Fv/F0, PIABS, ET0/RC, DI0/RC, ABS/RC in different time points in comparison to control, also Ag, Au and SnO2 treatment caused an increase in Fv/F0, PIABS or ET0/RC, respectively. On the other hand, TiO2-NPs caused a decrease in Fv/Fm and Fv/F0 parameters, but an increase in DI0/RC value was observed. SnO2-NPs decreased PIABS, but increased ET0/RC than compared to control. Nanoparticles affected the shape of the O-J-I-P curve in slight manner, however, further analyses showed unfavourable changes within the PSII antenna, manifested by a slowdown in the transport of electrons between the Chl molecules of the light-harvesting complex II and the active center of PSII due to NPs application. CONCLUSION: Changes in ChlF parameters and leaf reflectance values clearly proved the significant influence of NPs on the functioning of the photosynthetic apparatus, especially right after NPs application. The nature of these changes was strictly depended on the type of nanoparticles and sometimes underwent very significant changes over time. The greatest changes in ChlF parameters were caused by Fe2O3 nanoparticles, followed by TiO2-NPs. After slight response of O-J-I-P curves to treatment of the plants with NPs the course of the light phase of photosynthesis stabilized and at 9th day were comparable to the control curve.

Target volume for postoperative radiotherapy in non-small cell lung cancer: results from a prospective trial.

BACKGROUND AND PURPOSE: A previous prospective trial reported that three-dimensional conformal postoperative radiotherapy (PORT) for pN2 NSCLC patients using a limited clinical target volume (CTV) had a late morbidity rate and pulmonary function that did not differ from those observed in pN1 patients treated with surgery without PORT. The aim of this study was to assess locoregional control and localization of failure in patients treated with PORT. MATERIALS AND METHODS: The pattern of locoregional failure was evaluated retrospectively in 151 of 171 patients included in the PORT arm. The CTV included the involved lymph node stations and those with a risk of invasion >10%. Competing risk analysis was used to assess the incidence of locoregional failure and its location outside the CTV. RESULTS: Overall survival at 5years was 27.1% with a median follow-up of 67months for 40 living patients. The 5-year cumulative incidence of locoregional failure was 19.4% (95% CI: 18.2-20.5%) including a failure rate of 2% (95% CI: 0-17%) in locations outside or at the border of the CTV. CONCLUSIONS: The use of limited CTV was associated with acceptable risk of geographic miss. Overall locoregional control was similar to that reported by other studies using PORT for pN2 patients.

Cardiopulmonary morbidity and quality of life in non-small cell lung cancer patients treated with or without postoperative radiotherapy.

AIM: To prospectively assess the cardiopulmonary morbidity and quality of life in patients with non-small cell lung cancer (NSCLC) treated with postoperative radiotherapy (PORT) in comparison to those not receiving PORT. MATERIALS AND METHODS: From 2003 to 2007, 291 patients entered the study; 171 pN2 patients received 3D-planned PORT (PORT group), 120 pN1 patients (non-PORT group) did not. One month after surgery, all patients completed EORTC QLQ C-30 questionnaire and had pulmonary function tests (PFT); cardiopulmonary symptoms were assessed by modified LENT-SOM scale. Two years later, disease-free patients repeated the same examinations. The differences between baseline values and values recorded at two years in QLQ, LENT-SOM and the PFT of the two groups were compared. RESULTS: In the whole cohort, the rate of non-cancer related deaths was 5.3% and 5.0% in PORT and non-PORT group, respectively. Ninety-five patients (47 - PORT group, 48 - non-PORT group) were included into the final analysis. The differences in the QLQ and cardiopulmonary function (LENT/SOM, PFT) between both groups were insignificant. The forced expiratory volume in one second was on average 12.2% and 1.3% better in the PORT and the non-PORT group, respectively, p=0.2. CONCLUSIONS: Our findings support the hypothesis about insignificant morbidity of 3D-planned PORT.