[Photosynthetic characteristics of Leymus chinensis and Medicago sativa in artificial grassland]. / ç¾Šè‰å’Œç´«èŠ±è‹œè“¿äººå·¥è‰åœ°å ‰åˆç‰¹æ€§.

To explore the effect of monoculture and mixture sowing artificial grassland on the photosynthetic characteristics of Leymus chinensis and Medicago sativa, we determined the diurnal variation of photosynthetic properties of L. chinensis and M. sativa under different treatments. The results showed that the diurnal changes of net photosynthetic rate, blade temperature and transpiration rate of L. chinensis and M. sativa showed 'unimodal type' in monoculture, the stomatal conductance of M. sativa showed 'unimodal type', and the stomatal conductance and water use efficiency of L. chinensis showed 'bimodal type'. Under the mixed sowing treatment, the diurnal changes of net photosynthetic rate, blade temperature and transpiration rate of L. chinensis and M. sativa showed 'unimodal type', the stomatal conductance and water use efficiency of L. chinensis showed 'unimodal type', and the stomatal conductance of M. sativa showed 'bimodal type'. The peak photosynthetic rate of L. chinensis under mixture was signi-ficantly higher than that under monoculture, being 17.72 and 13.65 µmol CO2·m-2·s-1, respectively. Under monoculture and mixture sowing treatments, the chlorophyll content of L. chinensis was higher than that of M. sativa, nitrogen content of the leaves of L. chinensis was lower than that of M. sativa, and the nitrogen content in the leaves of mixture sowing L. chinensis was significantly higher than that of monoculture sowing L. chinensis, which were 27.60 and 22.55 g·kg-1, respectively. Net photosynthetic rates of L. chinensis and M. sativa were significantly positively correlated with stomatal conductance and transpiration rate, and significantly negatively correlated with intercellular CO2 concentration under different planting methods. Net photosynthetic rate of M. sativa was significantly positively correlated with blade temperature and water use efficiency. In summary, mixed sowing was beneficial to enhance nitrogen content of L. chinensis. Our results provided a theoretical basis for the response of the photosynthetic characteristics of forage to planting mode of artificial grassland.

Is there an impact of 18F-FDG PET/CT on the surveillance and clinical management of recurrent ovarian cancer? Research based on a large sample in a single PET/CT center.

OBJECTIVES: The aim of the study was to evaluate the use of F-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (CT) in the follow-up and clinical management of ovarian cancer patients after therapy. MATERIALS AND METHODS: A total of 152 ovarian cancer patients who had undergone therapy were evaluated. Clinical information, CA-125 levels, and traditional imaging findings were analyzed. According to the indication for PET/CT the patients were divided into five groups for assessing the role of (18)F-FDG PET/CT in the clinical management of ovarian cancer patients after therapy. A comparison was made between the PET/CT findings and the results of clinical follow-up. RESULTS: Of the 152 patients, 137 had follow-up results and 15 were lost to follow-up. A total of 105 patients were found to have recurrent tumor and 32 were found to be disease-free after long-term follow-up. The diagnostic sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 98.3, 91.2, 96.8, 97.5, and 93.9%, respectively. PET/CT was especially useful in patients when indications were to diagnose suspected recurrence, assess disease progression, and evaluate therapeutic response. CONCLUSION: PET/CT has been proven to be extremely valuable in the evaluation of patients with recurrent ovarian cancer and is particularly helpful in guiding treatment planning.

Can ¹8F-fluorodeoxyglucose positron emission tomography predict responses to neoadjuvant therapy in oesophageal cancer patients? A meta-analysis.

OBJECTIVES: Neoadjuvant therapy for the treatment of oesophageal cancer was introduced in an effort to improve prognosis. Response assessment is crucial for the treatment of patients with oesophageal cancer. Currently, ¹8F-fluorodeoxyglucose positron emission tomography (¹8F-FDG PET) seems to be the best available tool to assess neoadjuvant therapy response in patients with oesophageal cancer. The purpose of this study was to assess the diagnostic value of ¹8F-FDG PET for the evaluation of neoadjuvant therapy responses in patients with oesophageal cancer using a meta-analysis. A unified procedure and evaluation standard for ¹8F-FDG PET in the assessment of neoadjuvant therapy response should be established. METHODS: All published English-language studies pertaining to the assessment of neoadjuvant therapy response in patients with oesophageal cancer using ¹8F-FDG PET in the MEDLINE and EMBASE databases were collected. The methodological quality of the included studies was evaluated according to the Quality Assessment of Diagnostic Accuracy Studies quality assessment tool. Pooled sensitivity, specificity, diagnostic odds ratios and summary receiver operating characteristic curves were obtained using statistical software. RESULTS: Thirteen studies included in the meta-analysis fulfilled the inclusion criteria of the Quality Assessment of Diagnostic Accuracy Studies quality assessment tool. The pooled sensitivity, specificity and diagnostic odds ratios for F-¹8FDG PET in the evaluation of neoadjuvant therapy response in patients with oesophageal cancer were 70.3% [95% confidence interval (CI): 64.4-75.8], 70.1% (95% CI: 65.1-74.8) and 9.389 (95% CI: 3.482-25.319), respectively. The area under the curve and the Q value for the summary receiver operating characteristic curve were 0.8244 and 0.7575, respectively. CONCLUSION: ¹8F-FDG PET has some value in the assessment of neoadjuvant therapy response in patients with oesophageal cancer. A 50% reduction in standardized uptake value between pretherapy and posttherapy positron emission tomography scans performed in the first 2 weeks after the initiation of neoadjuvant therapy is the optimal condition for predicting a response to neoadjuvant therapy in patients with oesophageal cancer.

Optimizing delayed scan time for FDG PET: comparison of the early and late delayed scan.

OBJECTIVES: Although dual-time-point scans have been widely used to improve the diagnostic efficacy of FDG PET in differentiating between malignant and benign lesions, no optimized delayed scan time-point has yet been recommended in clinical practice. Our study aimed to explore the most appropriate time for a delayed scan by comparing early and late delayed scans. METHODS: Eighty patients with suspected malignancy were given a three-phase (64 min, 110 min, 233 min after FDG injection) PET/CT scan. The maximum standardized uptake values (SUVs) in the three-phase scans were recorded as SUV1, SUV2 and SUV3, respectively, and compared among three-phase imaging. Retention indices (RIs) of each lesion in two delayed phases were calculated according to the formulae: RI1=SUV2-SUV1/SUV1 x100% and RI2=SUV3-SUV1/SUV1 x100%. RI1 and RI2 in both malignant and benign groups were assessed through correlation analysis. The diagnostic values of two delayed scans were compared through the analysis of the receiver operating characteristic curves. RESULTS: One hundred and nine of 148 lesions were malignant, and 39/148 lesions benign, which were verified by pathological, clinical, laboratory or radiological examination. RI1 and RI2 in malignancy were 14.8+/-13.1% and 10.8+/-20.5% respectively, and the correlation coefficient was 0.6 (P=0.0001). RI1 and RI2 in benign lesions were 11.3+/-28.2% and 9.3+/-42.4%, respectively, and the correlation coefficient was 0.6 (P=0.0001). The area under the ROC curve for RI1 was 0.627+/-0.050 (null hypothesis: true area=0.5, P=0.0130); whereas the area under the ROC curve for RI2 was 0.563+/-0.052 (null hypothesis: true area=0.5, P=0.2321), suggesting that the late delayed scan may have no diagnostic value. CONCLUSION: The retention index values in the two delayed phases have good relativity. The diagnostic value of early delayed imaging is higher than that of late delayed imaging. An early delayed scan, according to our research, should be recommended in clinical practice.