Objective: To examine the associations of arsenic and estrogen levels with the risk of papillary thyroid carcinoma, so as to provide insights into prevention of papillary thyroid carcinoma. Methods: Totally 57 patients with papillary thyroid carcinoma admitted to two tertiary hospitals in Urumqi, Xinjiang Uygur Autonomous Region in 2018 were selected as the case group, while 57 subjects with normal thyroid functions during the same period were selected as the control group. Subjects' gender, age, ethnicity, occupation and medical history of thyroid disease were collected using questionnaire surveys. Serum dimethyl arsenic acid (DMA) and monomethyl arsenic acid (MMA) were determined using high-performance liquid chromatography (HPLC) coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS), serum thyroid hormone (TSH) by radioimmunoassay, estradiol (E2) by enzyme-linked immunosorbent assay and estrogen receptor ERα and ERβ by western blotting. The associations of arsenic and estrogen levels with the risk of papillary thyroid carcinoma were evaluated using a multivariable logistic regression model. Results: There were 16 males (28.07%) and 41 females (71.93%) in the case group, with a mean age of (42.63±11.01) years, and there were 21 males (36.84%) and 36 females (63.16%) in the control group, with a mean age of (40.89±11.30) years. There were no significant differences between the case and control groups in terms of age (χ2=0.373, P=0.542), gender (χ2=1.000, P=0.317) or ethnic composition (χ2=0.291, P=0.590). The serum levels of TSH [2.85 (1.61) vs. 2.45 (1.79) μmol/L], E2 [74.93 (120.44) vs. 61.60 (37.35) pmol/L], ERα [1.49 (1.13) vs. 0.70 (0.31)], ERβ [1.59 (0.55) vs. 0.72 (0.36)], DMA [116.02 (100.48) vs. 32.33 (56.06) μg/L] and MMA [56.92 (47.90) vs. 27.90 (24.99) μg/L] were all significantly higher in the case group than in the control group (Z=-2.414, -2.292, -4.923, -5.167, -5.448 and -4.019, all P<0.05). Multivariable logistic regression analysis showed DMA (OR=1.013, 95%CI: 1.003-1.024) and E2 levels (OR=1.020, 95%CI: 1.004-1.036) were associated with the risk of papillary thyroid carcinoma. Conclusion Increased arsenic load and elevated estradiol levels may be associated with the risk of papillary thyroid carcinoma.

Objective To compare the accuracy of endoscopic ultrasound (EUS) with double contrast enhanced ultrasound ( DCUS) in the preoperative staging of gastric malignancies. Methods This study included 162 patients with biopsy proven gastric cancer who underwent surgical resection as primary management of their malignancies. All patients underwent DCUS and EUS prior to surgical intervention with the results of the ultrasound findings compared with the pathological stages of the resected specimen. Results Among the 162 gastric cancer patients, there were 42 cases of T1, 49 cases of T2, 56 cases of T3, and 15 cases of T4 tumors. The overall accuracy of DCUS and EUS for the determination of loco-regional tumor infiltration ( T Staging) was 77. 2% and 74. 7% , (χ2 = 0. 273, P = 0. 603). Comparison of ultrasound techniques revealed that DCUS was superior to EUS only for a tumor depth of T3 (χ2 =5. 009, P = 0.025). Lymph nodes were correctly staged with DCUS and EUS in 78.4% and 57. 4% of cases, respectively ( χ2 = 16. 370,P =0.001). Using DCUS, the sensitivity of the technique was 78. 4% with a specificity of 78. 5%. In comparison, EUS had a sensitivity of 49. 5% with a specificity of 69. 2%. DCUS also detected a higher incidence of positive lymph nodes than EUS for poorly differentiated (81. 5% vs. 42. 6% ,χ2 =17. 338, P < 0. 01) and overall tumor types (78.4% vs. 49. 5% , χ2 = 17.523, P < 0. 01). Conclusions Double contrast-enhanced ultrasonography offers another noninvasive approach for the preoperative evaluation of gastric cancer. DCUS was comparable to EUS in tumor depth evaluation. DCUS offers an advantage in the detection of lymph node metastases, especially in poorly differentiated tumors.