Polysaccharides from Dendrobium huoshanense possess immunostimulating activity, antioxidant activity and anticataract activity. In order to produce the active polysaccharides from Dendrobium huoshanense through cell culture, we investigated the effects of salicylic acid on cell growth, accumulation of polysaccharides and utilization of carbon source in suspension cultures of protocorm-like bodies from Dendrobium huoshanense. Although salicylic acid slightly inhibited the cell growth, it was beneficial to the utilization of carbon source, thus leading to significant increase in the contents of polysaccharides. The highest polysaccharide production occurred on the medium supplied with 100 micromoI/L salicylic acid. After 18 days of culture the production of polysaccharides reached 3.129 g/L, which was 1.63 times that of the control. Further, we established the kinetic models describing cell growth, polysaccharide production and carbon source utilization based on Logistic equation, Luedeking-Piret equation and Luedeking-Piret-Like equation. The calculated values from the kinetic models showed a good fit to the experimental values, suggesting that salicylic acid could be an effective compound to enhance the production of active polysaccharides from protcorm-like bodies from Dendrobium huoshanense.
Cell Culture Techniques ; methods ; Cell Proliferation ; drug effects ; Dendrobium ; growth & development ; metabolism ; Polysaccharides ; biosynthesis ; Salicylic Acid ; pharmacology

Objective: Currently, parathyroid hormone (PTH) is mainly measured by the second generation intact PTH (iPTH) assay which detects both full-length (1-84)PTH and (7-84)PTH fragments. The third generation whole PTH (wPTH) assay however has turned out to be specific for (1-84) PTH. The aim of this study is to investigate the features of plasma iPTH, (1-84)PTH, (7-84)PTH levels in patients with stage 5 chronic kidney disease (CKD), and evaluate the effects of parathyroidectomy (PTX) on above markers in severe secondary hyperparathyroidism (SHPT) patients. Methods: A cross-sectional study including 90 controls and 233 stage 5 CKD patients, and a prospective follow-up study in 31 severe SHPT patients were conducted. Plasma iPTH and (1-84)PTH levels were measured by the second and third generation assay, respectively. Circulating (7-84)PTH level was calculated by subtracting the (1-84)PTH value from the iPTH value. Results: Plasma levels of iPTH, (1-84)PTH, (7-84)PTH were higher (P<0.01), and (1-84)PTH/iPTH was lower (P<0.01) in stage 5 CKD patients than in controls. For severe SHPT patients with PTX (n=74), plasma iPTH, (1-84)PTH and (7-84)PTH concentrations were significantly increased compared to non-PTX group (n=159) (P<0.01), and the increase of (7-84)PTH level was more striking than (1-84)PTH. Meanwhile, the value of (1-84)PTH/iPTH was decreased (P<0.01). Plasma iPTH level was strongly correlated with (1-84)PTH level (r=0.980, P<0.01) in stage 5 CKD patients. Also, both iPTH and (1-84)PTH levels were positively correlated with serum alkaline phosphatase, dialysis vintage and serum phosphorus (P<0.01). After PTX (median interval of follow-up: 7.1 months), plasma iPTH, (1-84)PTH, (7-84)PTH concentrations were decreased (by 92.9%, 89.7%, 95.8%, P<0.01, respectively) greatly and (1-84)PTH/iPTH was increased (P<0.01). Conclusions In stage 5 CKD patients, plasma iPTH, (1-84)PTH, (7-84)PTH levels are greatly increased while (1-84)PTH/iPTH is decreased, and PTX can significantly improve abnormality of above markers in severe SHPT patients. The second generation PTH assay overestimates the severity of SHPT, and the accurate measurement of (1-84)PTH by the third assays is more conducive to diagnosis and treatment of CKD and SHPT patients.