Dosimetric Comparison of Postmastectomy Radiotherapy Plans for Synchronous Bilateral Breast Cancer, Including Regional Lymph Node Irradiation.

BACKGROUND: To investigate the optimal radiotherapy plans for synchronous bilateral breast cancer (SBBC) patients receiving postmastectomy radiotherapy (PMRT), including regional lymph node irradiation (RNI). METHODS: For 10 SBBC patients who underwent bilateral mastectomy and received bilateral PMRT with RNI, 3 integrally optimized plans with a single isocenter were designed for each patient in this retrospective study: intensity-modulated radiation therapy (IMRT) with 9 fixed beams (9F-IMRT), volumetric-modulated arc therapy (VMAT) with 2 pairs of half arcs (2F-VMAT), VMAT with 2 pairs of outer tangential arcs and 1 pair of 200-degree arcs (3F-VMAT). The paired t-test (in the case of normal variables) and Friedman's test (in the case of nonnormal variables) were applied to compare the planning target volumes (PTVs) and organs at risk (OARs) values of the 3 techniques. RESULTS: The 3 techniques provided adequate target dose coverage and comparable results for PTVs. For OARs, 3F-VMAT yielded the lowest mean or median values of the left lung (15.02 ± 1.57 Gy) and right lung (14.91 ± 1.14 Gy), heart (6.19 (1.96) Gy), coronary artery (15.96 ± 5.76 Gy) and liver (8.10 ± 2.70 Gy) which were significantly different from those of 9F-IMRT and 2F-VMAT. The percentages of volume at various doses (V5, V10, V20, and V30) of 3F-VMAT plans were also lower than or comparable with those of 9F-IMRT and 2F-VMAT. The monitor units (MUs) of 3F-VMAT were 31% higher than those of 9F-IMRT and comparable with those of 2F-VMAT; however, there were time savings and halved beam-on times (BOTs) compared to 9F-IMRT. CONCLUSIONS: The 3F-VMAT plan yielded comparable target coverage compared with 9F-IMRT and 2F-VMAT, was superior in dose sparing of normal tissues and enabled shorter BOTs, improving treatment efficiency. In our research, 3F-VMAT was the optimal radiotherapy technique for SBBC patients receiving PMRT including RNI.

Effect of Cryptococcus laurentii on inducing disease resistance in cherry tomato fruit with focus on the expression of defense-related genes.

The objective of this study was to prove and explain the disease resistance-inducing ability of Cryptococcus laurentii on cherry tomato, as well as assay its effect on fruit quality. Apart from disease incidence, activities of defense-related enzymes and expression of critical genes were studied. With pre-treatment of C. laurentii, disease incidences of Botrytis cinerea and Alternaria alternate infected fruits were both significantly reduced. Corresponding mechanism could be explained as C. laurentii can induce resistance in cherry tomato by activating the expression of important defense-related genes, such as genes involved in salicylic acid (SA) and jasmonic acid (JA) signaling pathways and genes encoding pathogenesis related proteins, thus activating comprehensive defense reaction against pathogen invasion. Coupled with the results that fruit color was improved and other physicochemical parameters remained uninfluenced, our study suggests that pre-treatment with C. laurentii can be a promising method to preserve cherry tomato fruits.

Comparison of the effects of three types of aminobutyric acids on the control of Penicillium expansum infection in pear fruit.

BACKGROUND: Aminobutyric acids were reported to have inhibitory effects on postharvest fungal diseases. The effects of α-aminobutyric acid (AABA), ß-aminobutyric acid (BABA) and γ-aminobutyric acid (GABA) on the control of Penicillium expansum infection in pear fruit were compared in the present study. RESULTS: BABA and GABA reduced the disease incidence of P. expansum infection in pear fruit when applied at an appropriate concentration and with a suitable treatment time. The efficacy of GABA was superior to BABA, whereas AABA had no inhibition effect. Three types of aminobutyric acids almost had no direct antifungal activity against P. expansum in vitro and in vivo, although BABA and GABA inhibited spore germination of P. expansum in vivo at a concentration of 100 mg L-1 when P. expansum was inoculated 24 h after treatment. Moreover, BABA and GABA enhanced catalase activity and all three aminobutyric acids enhanced peroxidase activity in pear fruit after being challenged by P. expansum, although BABA and GABA were more forceful than AABA. CONCLUSION: The position of the amino group in aminobutyric acids may be associated with the effects of aminobutyric acids on the control of postharvest fungal diseases. © 2016 Society of Chemical Industry.

Evaluation of yeasts from Tibetan fermented products as agents for biocontrol of blue mold of Nashi pear fruits.

A total of 20 strains of yeast isolated from Tibetan fermented products were screened for antagonism against blue mold of pear caused by Penicillium expansum. Six isolates that inhibited incidence of postharvest decay by 35% or more were selected for further screening. Among them, the most effective was Rhodotorula mucilaginosa. The results showed that washed cell suspensions of R. mucilaginosa yielded better antagonistic efficacy than unwashed cell-culture mixtures, cell-free culture filtrates, and autoclaved cell cultures. Biocontrol activity improved with increasing concentrations of incubated cells. The best concentration was 1×10(8) cells/ml, at which the incidence of decay was only 16.7% after 6 d of incubation. The germination of conidia of P. expansum in vitro was significantly inhibited by both washed cell-suspensions and unwashed cell-culture mixtures. Rapid colonization by yeast at different concentrations showed a relationship between yeast-cell concentration and biocontrol activity. Although the titratable acidity of pear fruits increased after treatment, R. mucilaginosa did not affect the total soluble solids or ascorbic acid content. This is the first study to report that the yeast R. mucilaginosa from Tibet Autonomous Region of China may have potential as an antagonist to control the postharvest decay of pear fruits.

Transcript profiling analysis of Rhodosporidium paludigenum-mediated signalling pathways and defense responses in mandarin orange.

To investigate the basis of inducible resistance response in postharvest mandarin orange, cDNA microarray and high-performance liquid chromatography were performed to study transcriptional and metabolic changes in Rhodosporidium paludigenum strain treated fruit. The microarray data mining revealed that R. paludigenum activated transcription of genes important for plant hormones, signalling transduction, stress and defensive responses in orange peel tissue. Moreover, up-regulation of phenylalanine and tyrosine metabolism, phenylpropanoids biosynthesis, and alkaloid biosynthesis I, were observed at the transcription level. Conversely, large amounts of genes involved in starch metabolism, oligosaccharide and glycoside metabolism were markedly repressed by R. paludigenum treatment. Activation of phenylpropanoids biosynthesis pathway was correlated with the increasing production of phenolic acids and their subsequent metabolite lignin, indicating antifungal metabolites indeed contributed to biocontrol yeast enhanced fruit protection. Our findings provide an important basis for understanding the mechanisms of resistance induction in mandarin orange, as well as for reducing postharvest losses.

Indole-3-acetic acid improves postharvest biological control of blue mold rot of apple by Cryptococcus laurentii.

Cryptococcus laurentii is a well-known postharvest biocontrol yeast; however, it cannot provide satisfactory levels of decay control when used alone. Here, we evaluated the effects of indole-3-acetic acid (IAA), a plant growth regulator, on the biocontrol efficacy of the yeast antagonist C. laurentii against blue mold rot caused by Penicillium expansum in apple fruit. Results showed that the addition of IAA at 20 microg/ml to suspensions of C. laurentii greatly enhanced inhibition of mold rot in apple wounds compared with that observed with C. laurentii alone. The addition of IAA at 20 microg/ml or lower did not influence the population growth of C. laurentii in wounds, but adverse effects were seen on C. laurentii when the concentration of IAA was increased to 200 microg/ml or above in vitro and in vivo. P. expansum infection in apple wounds was not inhibited when the pathogen was inoculated into the fruit wounds within 2 h after application of IAA; however, infection was reduced when inoculated more than 12 h after IAA application. Treatment of wounds with IAA at 20 microg/ml 24 h before pathogen inoculation resulted in significant inhibition of P. expansum spore germination and host infection. Application of IAA at 20 microg/ml also reduced P. expansum infection when it was applied 48 h before pathogen inoculation in the intact fruit. Thus, IAA could reinforce the biocontrol efficacy of C. laurentii in inhibiting blue mold of apple fruit by induction of the natural resistance of the fruit.