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.
To investigate the protective effect of propofol on ischemia/reperfusion induced spinal cord injury in rabbits and its influence on excitatory amino acid (EAA). Methods Sixty New Zealand white rabbits weighing 2.0-2.5 kg, half males and half females, were selected. The infrarenal circumaortic clamping model was used. And 6 mL/kg different fluids were continuously infused through a catheter into the aorta distal to the clamping site at a speed of 12 mL/(kg•h) during the 30 minutes ischemia period. According to the different infusing l iquids, the rabbits were randomized into 6 groups(n=10 per group): group A, normal sal ine; group B, 10% intral ipid; group C, propofol 30 mg/kg; group D, propofol 40 mg/kg; group E, propofol 50 mg/kg; group F, propofol 60 mg/kg. At 0, 6, 24, and 48 hours after reperfusion, neurologic outcomes were scored on a Tarlov scale system. At 48 hours after reperfusion, the number of normal neurons in the anterior spinal cord was counted, and concentration of EAA in the lumbar spinal cord was measured by high performance l iquid chromatography. Results The neuroethological score was better in groups C, D, E and F than that of groups A and B (P lt; 0.05), the score of group E was the highest (P lt; 0.05), and there was no significant difference between group A and group B (P gt; 0.05). The number of normal neurons in the anterior spinal cord of groups C, D, E and F was greater than that of groups A and B (P lt; 0.05), and group E was greater than groups C, D and F (P lt; 0.05). The concentration of EAA in groups A, B, C, D, E and F was greater than that of normal tissue, the group E was the lowest (P lt; 0.05), the groups A and B were the highest (P lt; 0.05), and there was no significant difference between group A and group B (P gt; 0.05). Concentrations of glutamate and aspartic acid were negatively correlated to normal neuron numbers in the anterior spinal cord and neuroethological scores 48 hours after reperfusion, and the corresponding correlation coefficient was — 0.613, — 0.536, — 0.874 and — 0.813, respectively (P lt; 0.01). Conclusion Propofol can significantly inhibit the accumulation of EAA in spinal cord and provide a protective effect against the ischemia/reperfusion injury induced spinal cord in rabbits.
Objective To quantify the mRNA expression of NMDAR1 gene in the retina of eyes with acute elevation of IOP in rabbit． Methods Tweenty-six eyes of 16 rabbits were divided into three groups: Group 1: The IOP of one eye in 10 rabbits was elevated to 60 mm Hg by ante ri or chamber infusion． Group 2: The another eye of the same rabbit in group 1 was maintained the IOP to 20 mm Hg by anterior chamber infusion． Group 3: Unilat eral eyes of six rabbits were enucleated to evaluate the mRNA levels as normal control group． PCR product was identified by Southern blotting and the mRNA expression level was quantified by RT-PCR． Results The results revealed no significant difference between group 1 and group 2． Conclusion This implies that acute elevated IOP may not affect the mRNA expression level of NMDAR1 gene． (Chin J Ocul Fundus Dis, 2001,17:50-51)
Objective To evaluate the effectiveness and safety of radiosensitizer metronidazole amino acidum natrium (CMNa) for esophagus carcinoma. Methods Databases including The Cochrane library, PubMed, EMbase, CBM, CNKI, VIP and WanFang Data were searched from their establishment dates to Feb. 1st 2012 for randomized controlled trials (RCTs) of CMMa for esophagus carcinoma. Two reviewers independently screened literature and assessed the quality of the included studies and extracted data. Meta-analysis waw conducted using RevMan 5.1 software. Results A total of 17 RCTs involving 1 475 patients met the inclusion criteria. Results of meta-analyses showed that: a) As for short-term response, the total effectiveness of the experimental group given CMNa plus radiotherapy was higher than the control group given radiotherapy alone (OR=3.51, 95%CI 2.44 to 5.07, Plt;0.000 01). b) Significant differences were found in the quality of life, and one and two year survival rates (OR=2.90, 95%CI 1.91 to 4.39, Plt;0.000 01; OR=1.95, 95%CI 1.21 to 3.15, P=0.006). In accordance with the P-value of 0.05, there was a significant difference in three-year survival rate (OR=2.28, 95%CI 1.16 to 4.49, P=0.02). c) As for safety, no significant differences were found in radiation pneumonitis, radiation esophagitis, myelosuppression and mucous membrane reactions. Conclusion CMNa plus radiotherapy has beneficial effects in the treatment of esophagus carcinoma and improves 1, 2 and 3-year survival rates, but more RCTs on the quality of life and safety evaluation are needed.
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.
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.
ObjectiveTandem mass spectrometry is used to observe the changes in amino acids level in peripheral blood of patients with chronic obstructive pulmonary disease (COPD) of different severity, and explore the related factors that affect the level of amino acids in COPD patients.MethodsA collection of 99 COPD patients from the First Affiliated Hospital of Jinzhou Medical University between May 2020 and August 2020 were divided into GOLD Ⅰ/Ⅱ group, GOLD Ⅲ group and GOLD Ⅳ group according to the results of their lung function. Thirty healthy physical examination subjects during the same period were enrolled as a healthy control group. Peripheral amino acids were detected by liquid chromatography-tandem mass spectrometry (LC-MS).ResultsThe metabolism of 11 amino acids was correlated with the onset of COPD and the disorder of amino acid metabolism became more significant with the aggravation of the disease, and branched-chain amino acids (leucine, valine) had statistically significant differences in the COPD patients with different GOLD grades (P<0.05 and VIP>1). The difference between glutamate and glutamine was statistically significant only in GOLD Ⅳ stage (P<0.05 and VIP>1). The content of tyrosine and phenylalanine gradually increased with the increase of disease severity, and had significant difference in GOLD stage Ⅳ (P<0.05).ConclusionsCOPD patients with different GOLD grades have obvious amino acid metabolism disorders, including insufficient intake of essential amino acids and increased amino acids related to muscle protein catabolism. Understanding the mechanism between amino acid metabolism and COPD may provide a new direction for the diagnosis and treatment of the disease.
ObjectiveTo investigate the postnatal changes in urinary metabolic amino acid levels in infants with retinopathy of prematurity (ROP) and their effect on ROP, and to analyze the amino acid metabolic pathways that may be involved in the development of ROP. MethodsA retrospective cohort study. From January 2020 to December 2023, 65 premature infants with severe ROP (ROP group) who were hospitalized, born with gestational age ＜32 weeks in Children's Hospital Affiliated to Zhengzhou University were included in the study. Fifty premature infants with matched sex and gestational age and no ROP were selected as the control group. Urine amino acids and their derivatives were detected by gas chromatography-mass spectrometry. The two groups were compared by independent sample t test. The metabonomics of urinary amino acids was analyzed by orthogonal partial least squares discriminant analysis (OPLS-DA) model. The variable projection importance (VIP) score ＞1 suggested that the substance was two groups of differentially expressed amino acids. The predictive value of urinary amino acids for severe ROP was compared by using the receiver's operating characteristic (ROC) curve and the area under the curve. After t test and metabolomics analysis, the two groups of amino acids with large differences were normalized and compared by Pearson correlation analysis. The Kyoto Encyclopedia of Genes and Genomes database was used to analyze the metabolic pathways of differentially expressed amino acids involved in ROP. ResultsCompared with the control group, the concentrations of oxalic acid -2 and thiodiacetic acid-2 in urine metabolites of children in ROP group were significantly decreased, while the concentrations of 4-hydroxybutyric acid-2, 3-methylpentadienoic acid-2(1), 2-ketoglutarate-ox-2(2) and 3, 6-epoxy-dodecanedioic acid-2 were significantly increased, with statistical differences (t=0.036, 0.005, 0.038, 0.032, 0.022, 0.011; P＜0.05). The results of OPLS-DA analysis showed that amino acids of urinary metabolites in ROP group and control group were distributed in the left and right regions of the scatter plot, and there was a satisfactory separation trend between the two groups (R2Ycum=0.057 4, Q2cum=0.025 7, P＜0.05). As shown in the S-Plot, the amino acids biased towards two stages are glycolic acid-2, phosphoric acid-3, oxalic acid-2, thiodiacetic acid-2, 4-hydroxybutyric acid-2, 3-methylcrotonylglycine-1, 3-methylpentadienoic acid-2(1), 2-ketoglutarate-ox-2(2) and 3, 6-epoxy- dodecanedioic acid-2, respectively. Eleven differentially expressed amino acids with VIP score ＞1 were screened, among which the highest VIP score was oxalate-2, glycerate-3, phosphoric acid-3, 3-methylcrotonylglycine-1, uranoic acid -3 and thiodiacetic acid-2. The difference of amino acid concentration between the two groups was the highest in 4-hydroxybutyric acid-2 and thiodiacetic acid-2. The correlation between oxalic acid-2 and glycerate-3 was the highest (r=0.830, P＜0.001), and most amino acids were positive correlated. ROC curve fitting analysis showed that the combined prediction of 11 differenly-expressed amino groups had the largest area under the curve (0.816), the cutoff value was 0.531, and the sensitivity and specificity were 83.1% and 70.0%, respectively. The enrichment analysis of these 11 amino acids with significant differences suggested that the main pathways involved included butyrate metabolism, glyoxylic acid and dicarboxylic acid metabolism and lipoic acid metabolism. ConclusionAbnormal amino acid metabolism of 4-hydroxybutyrate-2, 3-methylpentadienoic acid-2(1), thiodiacetic acid-2, 2-ketoglutarate-ox-2(2), 3, 6-epoxy-dodecanedioic acid-2 may have a certain effect on the occurrence of ROP.
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.