ObjectiveTo establish a stable laboratory model of temporary hypoparathyroidism following thyroid operation in rabbits. MethodsTwenty New Zealand white rabbits were randomized into 2 groups (the four parathyroid glands injured group and the two inferior parathyroid glands injured group, n=10 for each group). In the two inferior parathyroid glands injured group, blood supply vessels of the two inferior parathyroid glands were injured with ligation. In the four parathyroid glands injured group, total thyroidectomy (including two superior parathyroid glands) were performed and blood supply vessels of the two inferior parathyroid glands were injured with ligation. The number of the identified parathyroid glands were counted during operation. Serum calcium and parathyroid hormone (PTH) were evaluated preoperatively and postoperatively on 1 d, 2 d, 3 d, 5 d and in 1 week, 2 weeks, 3 weeks, and 4 weeks. Model achievement rate were calculated. ResultsFour parathyroid glands were identified in rabbits. The two superior parathyroid glands were in thyroid tissue which were identified with histology, and the two inferior parathyroid glands located in the fascia plane between the sternohyoid, sternothyroid muscles and the carotid artery which can easily be identified with naked eye. There were no significant difference in preoperative calcium and PTH between the two groups (P > 0.05). In the two inferior parathyroid glands injured group, significantly decreased in serum calcium were observed on 1 d, 2 d and 3 d after operation (P < 0.05). In the four parathyroid glands injured group, significantly decreased in blood calcium were observed on 1 d, 2 d, 3 d and 5 d after operation (P < 0.05). The lowest level of serum calcium was observed on 1 d in two groups. Postoperative serum PTH were significantly declined in two groups on 1 d, 2 d, 3 d, 5 d, and in 1 week, 2 weeks and 3 weeks (P < 0.05). The lowest serum PTH was also observed on 1 d in two groups. Significantly lower serum PTH were found in the four parathyroid glands injured group on 1 d, 2 d and 3 d than in the two inferior parathyroid glands injured group (P < 0.05). Lower PTH level were found in the four parathyroid glands injured group on 5 d, and in 1 week, 2 weeks, 3 weeks and 4 weeks, but no significance (P > 0.05). Positive correlation between serum calcium and PTH were noticed (r=0.771, P=0.000). Model achievement rate were higher on 3 d and 5 d in the four parathyroid glands injured group than that of the two inferior parathyroid glands injured group (P < 0.05). ConclusionsStable animal model of temporary hypoparathyroidism following thyroidectomy can be established by total-thyroidectomy plus ligation the blood vessels of the two inferior parathyroid glands. This model can be used for further study.
ObjectiveTo propose policy recommendations for improvement of the affordability of high cost medicines with significant public health implications under the patent system in China. MethodsThrough literature analysis and market investigation, this study targeted expensive life saving medicines under the patent protection, which are critical for the treatment of eight diseases with the most significant disease burden and critical social, economic and political impact for case studies, estimated the individual and insurance direct economic burden of medicines treatment. ResultsChemical product patent protection enhanced medicines price monopoly. The targeted medicines brought huge financial burden to Chinese citizens, especially to the rural residents. Breaking chemical product patent protection, achieving parallel importation or making generic drugs enter into the China's market, can save huge amount of medicines procurement budget for the government, and benefit the general public. ConclusionDeveloping and implementing medicines registration and intellectual property right protection strategies with public health perspective, adding continuously improved basic health insurance programs, can effectively promote the affordability of high cost medicines with significant public health, social, political and economic implications.