RESUMO
This study investigated the inhibition mechanism of root growth in wheat seedlings when exposed to different zinc (Zn) concentrations. All applied Zn concentration did not affect seed germination, but reduced root length; in contrast, only Zn at 3mM inhibited significantly the growth of shoot. The loss of cell viability and the significant increases of lignification as well as the increases of hydrogen peroxide (H(2)O(2)), superoxide radical (O(2)(-)) and malondialdehyde levels were observed in the root tissue exposed to Zn treatment. And also, Zn stress led to the inhibition of cell-wall bound peroxidase. Moreover, NADPH oxidase inhibitor diphenylene iodonium could block greatly the elevation of O(2)(-) generation in Zn-treated roots. Therefore, the increased H(2)O(2) generation was dependent on the extracellular O(2)(-) production derived from plasma membrane NADPH oxidase. In addition, the loss of cell viability and the significant increases of lignification in response to the highest Zn concentration may be associated with the remarkable reduction of root growth in wheat seedlings.
Assuntos
Raízes de Plantas/efeitos dos fármacos , Triticum/efeitos dos fármacos , Zinco/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , NADPH Oxidases/metabolismo , Oniocompostos/farmacologia , Oxirredução , Peroxidases/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Superóxidos/metabolismo , Triticum/crescimento & desenvolvimentoRESUMO
The treatment of recurrent cervical cancer, especially pelvic locoregional recurrence, is very challenging for gynecologic oncologists. This study investigated the efficacy and safety of intensity-modulated radiation therapy (IMRT)-based concurrent chemoradiotherapy (CCRT) with Endostar, a novel modified recombinant human endostatin, in patients with pelvic locoregional recurrence of cervical cancer following surgical treatment.This phase 2 study was conducted between May 2018 and May 2019 at a single center in the Qinghai-Tibet Plateau and enrolled 31 patients with pelvic locoregional recurrence of cervical cancer following surgical treatment. All patients were treated with IMRT-based CCRT for 6 weeks and intravenous infusions of Endostar (15âmg/m), which were administered on days 1 to 7 of CCRT, followed by rest for 4 weeks. After resting, chemotherapy with cisplatin (70âmg/m) plus paclitaxel (135-175âmg/m) was given every 3 weeks for a total of 4 treatments.Thirty-one patients were evaluable for the primary endpoint. The mean age was 50.03 years (SD 7.72). The objective response rate was 67.74% and the disease control rate was 83.87% (48.39% achieved a complete response, 19.35% a partial response, 16.13% had disease stabilization, and 16.13% had progressive disease). The most common adverse events were nausea, vomiting, alopecia, neutropenia, and leukopenia; most events were grade 1 or 2 in intensity. Grade 3 toxicities included thrombocytopenia and neutropenia in 2 patients each, and leukopenia in 4 patients. No cases of grade 4 acute toxicity were observed.IMRT-based CCRT with Endostar infusions is effective and safe. Our results support the use of this treatment for patients with pelvic locoregional recurrence of cervical cancer following surgical treatment.