Objective To explore the clinical significance of monitoring drainage fluid parathyroid hormone (dPTH) for estimating the in situ reserves and function of the parathyroid by analyzing the change of serum calcium,serum parathyroid hormone(sPTH) and dPTH after thyroid surgery.Methods According to the operative method,the total of 144 patients with thyroid disease were divided into five groups:unilateral lobectomy,unilateral lobectomy plus isthmectomy with unilateral lymph node dissection,total thyroidectomy,total thyroidectomy with unilateral lymph node dissection,and total thyroidectomy with bilateral lymph node dissection group.The blood calcium,sPTH and dPTH level of patients were tested before operation and on the 1st,2nd,3rd and 4th day after operation.The depression of serum calcium,hypocalcemia and hypoparathyroidism were observed after operation.The serum calcium,serum PTH and dPTH level were summarized and analyzed statistically in order to evaluate the in situ reserves and postoperative function of the parathyroid.Results Among the 114 cases,the decline of serum calcium level mostly happened on the 2nd day after operation(70 cases,61.4％).There were 36 patients with hypocalcemia (31.58％) and 34 patients with hypoparathyroidism (29.82％).Serum calcium level increased gradually in all of the patients.Although sPTH level swung,it had a rising trend on the whole.The level of serum calcium and sPTH was positively correlated.The level of dPTH was discrete and decreased along with time.The decline level of dPTH among different groups had statistical difference.Conclusions It is a promising method to evaluate the in situ reserves and function of the parathyroid by monitoring the level and changes of dPTH after thyroid surgery,and it is of value for preventive calcium supplementation after thyroid surgery.

Objective: To evaluate the effects of casein phosphopeptide-amorphic calcium phosphate (CPP-ACP) on enamel erosion using an improved in situ experimental protocol. Methods: Forty-eight enamel blocks were prepared from fresh-extracted human premolars and further embedded in the acrylic resins. The present study was divided into 2 parts. In part 1 of the study, two volunteers were recruited to test the availability and safety of the in situ erosion protocol. Customized intraoral appliance was made with 4 reservoirs containing the specimens for each volunteer. For each intraoral applicance, 2 reservoirs were made with the openings and the other 2 remained intact. All volunteers were instructed to drink 150 ml cola within 5 min using the gargling method after placing appliances intraorally for 2 h. After erosion, the appliances were remained undisturbed intraorally for 1 h until the next erosive attack. The in situ erosion cycles were performed 4 times daily over 7 d. In part 2 of the study, forty specimens were randomly divided into 2 groups (n=20): CPP-ACP group and control group. The surfaces of specimens in CPP-ACP group were pretreated with CPP-ACP for 3 min before in situ erosion, whereas the specimens in control group were pretreated with deionized water for 3 min. For each intraoral applicance, 4 reservoirs were made with openings. Ten healthy volunteers were recruited and the above-mentioned in situ erosion protocol was applied to test the effects of CPP-ACP on enamel erosion. The surface microhardness and surface microstructure of the samples were examined before and after erosion in both parts of the study. The data were statistically analyzed using ANOVA and LSD tests. Data were considered statistically significant at a level of P<0.05. Results: Significant surface softening was observed in all specimens after erosion (P<0.001). The surface microhardness in the CPP-ACP group and control group were (198.8±23.2) and (152.4±42.1) HV, respectively (P=0.040). The specimens in the CPP-ACP group showed significantly fewer changes in surface microstructure compared with those in the control group. Conclusions Based on this in situ experimental protocol, short-time consuming of acid beverages would produce significant effects on the surface microhardness of the human enamel, whereas the application of CPP-ACP can increase the erosion resistance of the enamel.

Objective: To explore the clinical significance of metastasis of lymph nodes between sternocleidomastoid and sternohyoid muscle (LNSS) in papillary thyroid cancer (PTC). Methods: A total of 175 patients with PTC who underwent thyroidectomy with LNSS dissection were retrospectively analyzed. Univariate and multivariate Logistic regression analyses were used to determine the independent risk factors for LNSS metastasis in PTC. Results: The rate of detectable LNSS was 70.9% (124/175) and metastasis rate was 7.4% (13/175). Of 13 cases with LNSS metastasis, 10 with the coexistence of cervical lymph node metastasis. Univariate Logistic regression analysis showed that multiple focal cancer, tumor located in the lower pole of thyroid, belt-shaped muscle invasion, lateral cervical lymph node metastasis, cN+ , the number of cervical lymph nodes with metastasis and the number of lymph nodes with metastasis in level Ⅳwere the risk factors for LNSS metastasis (P<0.05). Multivariate Logistic regression analysis suggested that tumor located in the lower pole of thyroid and the number of cervical lymph nodes with metastasis >6 were the independent risk factors for LNSS metastasis (P<0.05). Given the number of cervical lymph nodes with metastasis as a predictor for the LNSS metastasis, the sensitivity was 92.3%, the specificity was 66.7% and the accuracy rate was 68.6%. Conclusions LNSS metastasis is commom in PTC, with a metastasis rate of 7.4%. PTC in the lower pole of thyroid and the number of cervical lymph nodes with metastasis > 6 are independent risks for LNSS metastasis.