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)
目的：建立高效液相色谱分离检测脑蛋白水解物注射液各种氨基酸的测定方法。方法：氨基酸含量测定采用异硫氰酸苯酯柱前衍生化；色谱柱为C18柱（VP-DOS；150 mm×46 mm）；流动相：A为0.1 mol/L醋酸钠溶液（冰醋酸调节pH 6.5）-乙腈（93∶7），B为水-乙腈（1∶4）；检测波长：254 nm；流速：1 mL/min；柱温：40℃。结果：16种氨基酸在32 min内完全分离，各种氨基酸之间没有出现干扰现象，且多次重复测定结果误差很小。结论：建立的高效液相色谱法准确性高、重现性好，可以有效地控制脑蛋白水解物注射液的质量。
Objective To investigate the change of N-terminal pro-B-type natriuretic peptide ( NT-proBNP) levels in plasma of patients with stable chronic obstructive pulmonary disease ( COPD) at exertion. Methods Pulmonary function testing, increamental and constant cycle ergometer exercise testing were performed in 19 patients with stable COPD and 10 healthy subjects. Arterial blood gas analysis were measured at rest and maximal exertion in incremental testing. Venous blood samples were drawn both at rest and maximal exercise in constant-load exercise testing and NT-proBNP levels were measured. Results NT-proBNP levels did not change significantly during exercise in the patients with stable COPD[ ( 4803. 86 ±1027. 07 ) ng/L vs ( 4572. 39 ±1243. 33 ) ng /L, P = 0. 542 ] and the control group [ ( 4303. 18 ±771. 74) ng/L vs ( 4475. 71 ±1025. 50) ng /L, P = 0. 676] . NT-proBNP levels were not correlated with parameters of cardiopulmonary exercise testing. Conclusion The factors other than cardiac function may contribute to the exercise intolerance in stable COPD patients without heart failure.
Objective To summarize and analyze the clinical data of maple syrup urine disease (MSUD) patients to explore the correlation among clinical phenotype, biochemical markers and genotype. Methods The clinical data of 11 children with MSUD who were admitted to Guangzhou Women and Children’s Medical Center of Guangzhou Medical University between January 2011 and October 2016 were retrospectively collected. According to the clinical symptoms and prognosis, they were divided into classic type group (n=6) and intermediate/thiamine-effective group (n=5). The differences in biochemical metabolic markers between the two groups were compared, and the correlation between genotype and phenotype was analyzed. Results Compared to the intermediate/thiamine-effective group, the blood gamma-glutamyltransferase (γ-GT) level in the classic type group was significantly higher [158.00 (122.80, 309.30) vs. 11.00 (10.50, 14.00) U/L, P=0.004], and the globulin [(15.55±3.45) vs. (24.26±4.37) g/L, P=0.018] and lactate [1.05 (0.98, 1.68) vs. 2.10 (1.75, 2.70) mmol/L, P=0.030] levels in the classic type group were significantly lower, while the levels of alanine aminotransferase, aspartate aminotransferase and total bile acid were not different between the two groups (P>0.05). The plasma concentrations of leucine in the classic type group were higher than that in the intermediate/thiamine-effective group [(3748.20 (3135.00, 4936.00) vs. 620.40 (531.20, 1150.00) μmol/L, P=0.004]. The γ-GT level was positively correlated with the leucine level (rs=0.826, P=0.003), the leucine level was positively correlated with the iso-leucine level (rs=0.827, P=0.003), and the iso-leucine level was positively correlated with the valine level (rs=0.636, P=0.040). The results of gene sequencing showed that the 11 patients carried BCKDHA (n=4) and BCKDHB (n=7) gene mutations, respectively. Of these, 6 patients with BCKDHB gene mutations were classic type. Conclusion The prognosis of MSUD is closely correlated to blood γ-GT and branched-chain amino acids levels, as well as with genotype.
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.
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.
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.
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)
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.
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.