Heat sensitive protein medicines are increasingly exhibiting their critical importance on treatment of various diseases at present. But their popularization and application meet a great challenge because of their heat instability. In the present study, insulin was taken as a heat sensitive protein medicine and amino acid as bio-protective agent in order to investigate if these amino acids can protect the insulin from losing its bioactivity due to desiccation. The experiment was performed by using replica exchange molecular simulation (REMD) method and Gromacs software with Gromos96 (53a6) force field. The REMD results indicated that these amino acids could protect the bioactive structure of insulin during desiccation. The configurations of the protected insulin were preserved very well. Those results proved that amino acid is a kind of good bioactive protective agent for the heat sensitive protein medicines.
Objective To monitor the release of amino acids of the whole retina during and after experimental glaucoma by increasing the intraocular pressure （IOP）． Methods Experimental glaucoma was induced in one of the two eyes of rabbits by increasing IOP at 120 mm Hg for 45 min under infusion of saline in anterior chamber；then the pressure was released and the needle inserted into the anterior chamber was removed，this state was maintained for another 45 min．Every 15 min during the experiment 5 rabbits were killed and experimental eyes were enucleated．Aliquots（20 μl）of the retinal extracts（see below）were mixed with ophthaldialdehyde reagent and analysed for amino acid content by the HPLC method of Wangwei，using a 150 mm×4.6 mm,5 μm C18 column． Results A large increase in the release of glutamate，but not of the other three amino acids monitored，occurred during initial experimental ocular hypertension．It reached peak value of（111.73±17.46）10-5 mmol/g at 15 min of hypertension．15 min after release of intraocular pressure，again，immediately large and specific increase in the concentration of glutamate was reached to（102.96±51.91）10-5 mmol/g．In eyes subjected to paracentesis of anterior chamber，no difference was found between experimental eyes and controls. Conclusion These results suggest that glutamate is triggered by increasing the IOP，and it releases not only during the period of experimental ocular hypertension，but also afterwards. (Chin J Ocul Fundus Dis, 2002, 18: 146-148)
ObjectiveTo understand the function of trace element and amino acids detection in early diagnosis of breast cancer, and explore the correlation between plasma amino acid and trace element changes. MethodsFifty-five patients with breast cancer and 50 normal controls were included in our study from May 2012 to June 2013. Trace elements were detected by atomic absorption spectrophotometer, and the level of amino acids was detected by Hitachi L-8900 amino acids analyzer. Then, we analyzed the correlation between the two indexes. ResultsCompared with the normal controls, breast cancer patients had a higher level of Cu and Fe (P<0.05), and a lower level of Zn (P<0.05). Seven kinds of amino acids had significant changes (P<0.05), including three kinds of increased amino acids, and four reduced. Amino acids and trace element correlation analysis showed that Mg was negatively correlated with Leu, Tyr, Lys, and His; and Ca was negatively correlated with Lys and His. ConclusionThere are many kinds of changes of plasma amino acids and trace elements in breast cancer patients. Serum trace element and amino acids detection in patients with breast cancer are helpful in the severity judgment and regimen design.
ObjectiveTo evaluate the effect of poly-amino acid/nano-hydroxyapatite/calcium sulfate (PHC) Cage in lumbar interbody fusion of the goat. MethodsEighteen mature female goats (weighing 29-33 kg) were divided into 3 groups randomly: PHC Cage group (group A), titanium Cage group (group B), and ilium group (group C). A left extraperitoneal approach was used to establish the animal model of discectomy and interbody fusion with Cage or ilium. The general situation was observed for 24 weeks after operation. X-ray films were taken to measure disc space height (DSH) before operation and at 4, 12, and 24 weeks after operation. CT three dimensional reconstuction was performed at 24 weeks after operation to evaluate the interbody fusion according to modified Brantigan grading. The specimens of L3, 4 were harvested for mechanical test, histological, and scanning electron microscope (SEM) observation at 24 weeks after operation. ResultsAll goats survived to the end of experiment. DSH at 4 weeks after operation increased when compared with preoperative one in each group, and then decreased;DSH was significantly lower at 12 and 24 weeks after operation than preoperative one in group C (P<0.05). There was no significant difference in DSH among 3 groups at preoperation and 4 weeks after operation (P>0.05);at 12 and 24 weeks after operation, DSH of groups A and B was significantly higher than that of group C (P<0.05), but no significant difference was found between groups A and B (P>0.05). CT three dimensional reconstuction showed that bony fusion was obtained in all goats of groups A and C, and in 3 goats of group B;according to modified Brantigan grading, the scores of groups A and C were significantlly higher than that of group B (P<0.05), but no significant difference between groups A and C (P>0.05). The biomechanical test showed that there was no significant difference in range of motion between group A and group B (P>0.05), which were significantly lower than that of group C (P<0.05). Microscopy and SEM observations showed that the interface between the Cage and vertebral body in group A was compact without obvious gap, and most conjunctive region was filled with osseous tissue;the interface was filled with soft tissue, and the connection was slack with obvious gap in some region in group B;the interface connection was compact, most region was filled with osseous tissue in group C. ConclusionThe interbody fusion with PHC Cage is effective in goat lumbar interbody fusion model. The interface connection is compact between the Cage and the host bone followed by micro-degradation of PHC Cage, but the long-term degradation need further observation.
ObjectiveTo observe the ability of osteogenesis in vivo using the injected absorbable polyamine acid/calcium sulfate (PAA/CS) composites and assess their ability to repair bone defects. MethodWe selected 48 New Zealand white rabbits, and half of them were male with a weight between 2.0 and 2.5 kg. Bone defect models were made at the rabbit femoral condyle using electric drill, and the rabbits were divided into two groups. One group accepted implantation of the material at the defect, while nothing was done for the control group. After four, eight, twelve and sixteen weeks, the animals were killed. The line X-ray and hard tissue slices histological examination (HE, MASSON staining) were observed to assess the situation of degradation, absorption and bone formation of the material. ResultsFour weeks after operation, bone defect of the experimental group had no obvious callus growth on X-ray imaging. Histology showed that the material began to degrade and new immature trabecular bone grew. The bone defect of the experimental group had a small amount of callus growth on X-ray imaging after eight weeks. And histology showed that the material continued to degrade and new immature trabecular bone grew continually. There was an obvious callus growth after twelve weeks, and the bone defect area had smaller residual low-density shadow on X-ray imaging. Histology showed that most of the materials degraded and parts of woven bone grew into lamellar bone. After sixteen weeks, the composites were absorbed completely, replaced by new bone tissues, and the new bone was gradually changed from woven bone into mature plate of bone. There was no significant change in bone defect in the control group within twelve weeks, and part of bone defect hole became smaller, and partial edge repair could be detected. ConclusionsThe PAA/CS composites can be completely degraded and absorbed, with a certain activity of bone formation, expected to be used as bone repair materials.
【Abstract】 Objective To study the effects of glutamine (Gln) combined with growth hormone （GH） on the levels of cytokine (TNF-α, IL-1, IL-6), coritsol and amino acid metabolism in septic rats. Methods Ten out of 79 SD rats were randomly collected as the control group. Thirty of 69 septic SD rats, which were made by cecal ligation and perforation (CLP) method and were given parenteral nutrition (PN) lived to day 6. They were also randomly divided into three groups as follows: septic group (n=10), parenteral supplemented glutamine group (Gln group, n=10), and Gln combined with GH (Gln+GH group, n=10). On the 6th day, blood drew from portal veins of the dead rats was used to detect the levels of TNF-α， IL-1， IL-6 and cortisol by ELISA. The plasma concentrations of free amino acids were determined by amino acid auto-analyzer. The muscle tissue of extensor digitorum longus was used to determine 3-methyl-histidine (3-MH) by high performance liquid chromatographic (HPLC). Results Except for the control group, most rats developed celiac abscess, hepatic abscess and pulmonary infection. The serum levels of TNF-α, IL-1, IL-6 and cortisol were significantly higher in the septic group than those of the other three groups, and they were significantly lower in the Gln+GH group than those of the Gln group, P＜0.05. Compared with the other three groups, the concentration of total amino acid in the septic group increased more, among which the glutamine and the branched chain amino acids were prominent. Most of concentrations of the amino acids decreased in the Gln group and the Gln+GH group, and the decreased amplitude of the Gln+GH group was larger, P＜0.05, albeit its level of Gln markedly increased. The concentration of 3-MH in muscle tissue was the highest in septic group, and it was significantly higher in the Gln group than that of the Gln+GH group, P＜0.01. ConclusionIt may be necessary to supplement GH combined with Gln as the content of PN to decrease cytokine levels and im-prove amino acid metabolism for septic case.
Objective To investigate the effect of early postoperative enteral nutrition support on the balance of free amino acid spectrum in plasma for patients with cardiac valve replacement during perioperative period. Methods (Forty-seven) patients undergoing cardiac valve replacement were divided into two groups randomly, the routine diet group and the Nutrison Fibre group. The levels of free amino acids in plasma were measured with pre-column derivatization of high-performance liquid chromatography. Results During perioperative period most free amino acids in plasma decreased significantly in the routine diet group (Plt;0.05). Despite some free amino acids in plasma decreased significantly in the Nutrison Fibre group(Plt;0.05), all free amino acids in plasma returned to (Pgt;05) or were higher than the preoperative levels in the postoperative sixth day (Plt;0.05). At the same postoperative points, most free amino acids in plasma in the Nutrison Fibre group were higher than that of the routine diet group (Plt;0.05). Conclusions The levels of free amino acids in plasma decrease significantly in patients with cardiac valve replacement after operation. Early postoperative Nutrison Fibre enteral nutrition support is helpful for keeping the balance of free amino acids in plasma for patients with cardiac valve replacement.
Skeletal muscle and metabolic function are important factors affecting the health status of the elderly. Branched-chain amino acids (BCAA) can improve muscle recovery, reduce muscle soreness after exercise, and BCAA can also enhance metabolic health, helping to regulate blood sugar levels and improve insulin sensitivity in the elderly. In addition, BCAA can improve cognitive function, reducing the risk of age-related cognitive decline. This article reviews the relationship between BCAA and aging, skeletal muscle, and metabolic diseases, explaining how BCAA can support and promote muscle mass and function in the elderly, as well as have a positive impact on metabolic health and cognitive function.
Objective To review the latest researches of synthetic biodegradable polymers for bone repair and reconstruction, to predict the progress of bone substitute materials and bone tissue engineering scaffolds in future. Methods The l iterature concerning synthetic biodegradable polymers as bone substitute materials or bone tissue engineering scaffolds was collected and discussed. Results Al i phatic polyester, polyanhydride, polyurethane and poly (amino acids) were the most extensively studied synthetic biodegradable polymers as bone substitutes and the scaffolds. Each polymer was of good biological safety and biocompatibil ity, and the degradation products were nontoxic to human body. The mechanical properties and degradation rate of the polymers could be adjusted by the type or number of the monomers anddifferent synthetic methods. Therefore, the polymers with suitable mechanical strength and degradation rate could be produced according to the different requirements for bone grafting. Prel iminary studies in vivo showed their favorable capacity for bone repair. Conclusion The synthetic biodegradable polymers, especially the copolymers, composite materials and those carrying bone growth factors are expected to be the most promising and ideal biomaterials for bone repair and reconstruction.