Assessing Lysine Requirement of Growing Chicken by Direct Comparison between Supplementation Technique and “Goettingen Approach”

Validated procedures play an important role to obtain accurate information about individual amino acid requirement data. The aim of the present study was to assess lysine (Lys) requirement of growing chicken both by classical supplementation technique and principles of diet dilution technique as applied with “Goettingen approach”. During the starter period (1 - 21 d), a growth study with male meat type chicken (Ross 308) was conducted making use of five graded dietary Lys-levels (3 repetition boxes with 3 birds/box). L-Lys×HCl was gradually added to a diet based on wheat, soybean protein concentrate, wheat gluten and fishmeal to yield 80%, 87.5%, 95%, 102.5% and 110% of the expected requirement level (13 g Lys/kg as fed). Diets were iso-energetic (12.8 MJME/kg) and iso-nitrogenous (21.65% crude protein). Birds were fed on free choice level also to assess the feed intake (FI) effects as important factor on traditional response criteria. Analyzed body composition at start and end of the growth study yielded N deposition (ND) data for further data assessment using exponential approximations depending on dietary Lys content or observed Lys intake. The results indicated significant differences (p < 0.05) in response on body weight gain (BWG) and observed dietary protein quality with unexpected consequences for the derived Lys requirement data. According to the independent variable (Lys in % of diet versus daily Lys intake) and aimed level of daily ND, the needed in-feed content of Lys varied between 1.24% and 1.46%. Application of the exponential modelling by “Goettingen approach” overcame these misleading conclusions by modelling the relationship between required Lys intake and observed response data (BWG, ND) taking also into account the expected real feed intake to formulate the needed in-feed concentration.

Validation of the Lysine Requirement as Reference Amino Acid for Ideal In-Feed Amino Acid Ratios in Modern Fast Growing Meat-Type Chickens

Nitrogen (N) balance studies were conducted with male growing broiler chickens to reevaluate the lysine (Lys) requirement of a modern broiler strain (Ross 308), making use of eight diets with graded crude protein (CP) supply (6% - 34% CP as-fed). Wheat, soy protein concentrate, wheat gluten, fishmeal and crystalline amino acids (AAs) were the protein sources in the experimental diets with Lys as limiting AA. Following an adaptation period of five days, two consecutive excreta collection periods (2 × 5 d) were conducted: 10 - 20 d of age (starter period) and 25 - 35 d of age (grower period). Statistical evaluation of N balance data utilized an exponential modelling approach. Based on different dietary Lys efficiency, Lys requirement data were derived by modelling depending on average body weight (BW) during starter and grower period and targeted body protein deposition (PD), respectively. In addition, the influence of graded feed intake was taken into account. For the starter period at 600 g BW and assumed 10 g daily body PD, Lys requirement data between 741 mg and 823 mg per day were observed. The corresponding Lys in-feed concentration was 1.06% and 1.18%, dependent on supposed Lys efficiency at 70 g daily feed intake. For the grower period (average BW 1800 g), 1272 mg to 1473 mg Lys per day was needed to yield 16.5 g daily PD. The corresponding required Lys in-feed concentration was between 0.85% and 0.94% Lys for 150 g daily feed intake.

An Elevated Dietary Cysteine to Methionine Ratio Does Not Impact on Dietary Methionine Efficiency and the Derived Optimal Methionine to Lysine Ratio in Diets for Meat Type Chicken

Optimal dietary methionine (Met) to lysine (Lys) ratio in presence of elevated dietary cysteine (Cys) levels was derived for meat type growing chicken. Twelve averaged weighed Ross 308 birds (each 50% of male and female per dietary treatment) were utilized in N balance trials. During starter (d10 - 20) and grower period (d25 - 35) five dietary treatments were used. Diets based on uniform mixtures of maize, wheat, soybean meal, potato protein and fish meal were supplemented with crystalline amino acids (AA). In diets 1 - 3, the dietary Cys to Met ratio was set as 85, 95 and 105 to 100, respectively. Diet 4, at a Cys to Met ratio of 105 to 100, was additionally supplemented with betaine (BET) as methyl group donor. Diets 1 - 4 were limiting in Met, diet 5 without L-Lys·HCl addition was limiting in Lys. Individual N-balance data per treatment were utilized for assessing protein quality and efficiency of dietary Met (Diets 1 - 4) or Lys (Diet 5) based on “Goettingen approach”. Elevated dietary Cys supply and supplemented BET failed to improve both dietary protein quality and Met efficiency. The established optimal Met to Lys ratio was on average 34 to 100 for growing chicken during starter and grower period, respectively.

Dietary Nε-(carboxymethyl)lysine affects cardiac glucose metabolism and myocardial remodeling in mice

BACKGROUND Myocardial remodeling is a key factor in the progression of cardiovascular disease to the end stage.In addition to myocardial infarction or stress overload,dietary factors have recently been considered associated with myocardial remodeling.Nε-(carboxymethyl)lysine(CML)is a representative foodborne toxic product,which can be ingested via daily diet.Therefore,there is a marked need to explore the effects of dietary CML on the myocardium.AIM To explore the effects of dietary CML(dCML)on the heart.METHODS C57 BL/6 mice were divided into a control group and a dCML group.The control group and the dCML group were respectively fed a normal diet or diet supplemented with CML for 20 wk.Body weight and blood glucose were recorded every 4 wk.^(18)F-fluorodeoxyglucose(FDG)was used to trace the glucose uptake in mouse myocardium,followed by visualizing with micro-positron emission tomography(PET).Myocardial remodeling and glucose metabolism were also detected.In vitro,H9C2 cardiomyocytes were added to exogenous CML and cultured for 24 h.The effects of exogenous CML on glucose metabolism,collagen I expression,hypertrophy,and apoptosis of cardiomyocytes were analyzed.RESULTS Our results suggest that the levels of fasting blood glucose,fasting insulin,and serum CML were significantly increased after 20 wk of dCML.Micro-PET showed that ^(18)F-FDG accumulated more in the myocardium of the dCML group than in the control group.Histological staining revealed that dCML could lead to myocardial fibrosis and hypertrophy.The indexes of myocardial fibrosis,apoptosis,and hypertrophy were also increased in the dCML group,whereas the activities of glucose metabolism-related pathways and citrate synthase(CS)were significantly inhibited.In cardiomyocytes,collagen I expression and cellular size were significantly increased after the addition of exogenous CML.CML significantly promoted cellular hypertrophy and apoptosis,while pathways involved in glucose metabolism and level of Cs mRNA were significantly inhibited.CONCLUSION This study reveals that dCML alters myocardial glucose metabolism and promotes myocardial remodeling.

Nε-(carboxymethyl)lysine promotes lipid uptake of macrophage via cluster of differentiation 36 and receptor for advanced glycation end products

BACKGROUND Advanced glycation end products(AGEs)are diabetic metabolic toxic products that cannot be ignored.Nε-(carboxymethyl)lysine(CML),a component of AGEs,could increase macrophage lipid uptake,promote foam cell formation,and thereby accelerate atherosclerosis.The receptor for AGEs(RAGE)and cluster of differentiation 36(CD36)were the receptors of CML.However,it is still unknown whether RAGE and CD36 play key roles in CML-promoted lipid uptake.AIM Our study aimed to explore the role of RAGE and CD36 in CML-induced macrophage lipid uptake.METHODS In this study,we examined the effect of CML on lipid uptake by Raw264.7 macrophages.After adding 10 mmol/L CML,the lipid accumulation in macrophages was confirmed by oil red O staining.Expression changes of CD36 and RAGE were detected with immunoblotting and quantitative real-time polymerase chain reaction.The interaction between CML with CD36 and RAGE was verified by immunoprecipitation.We synthesized a novel N-succinimidyl-4-18Ffluorobenzoate-CML radioactive probe.Radioactive receptor-ligand binding assays were performed to test the binding affinity between CML with CD36 and RAGE.The effects of blocking CD36 or RAGE on CML-promoting lipid uptake were also detected.RESULTS The study revealed that CML significantly promoted lipid uptake by macrophages.Immunoprecipitation and radioactive receptor-ligand binding assays indicated that CML could specifically bind to both CD36 and RAGE.CML had a higher affinity for CD36 than RAGE.ARG82,ASN71,and THR70 were the potential interacting amino acids that CD36 binds to CML Anti-CD36 and anti-RAGE could block the uptake of CML by macrophages.The lipid uptake promotion effect of CML was significantly attenuated after blocking CD36 or RAGE.CONCLUSION Our results suggest that the binding of CML with CD36 and RAGE promotes macrophage lipid uptake.

Blood Compatibility of Amphiphilic Poly(N-α-acrylamide-L-lysine-<i>b</i>-dimethylsiloxane) Block Copolymers

Amphiphilic block copolymers poly(LysAA-b-DMS) consisting of a hydrophilic poly(N-α-acrylamide-L-lysine) [poly(LysAA)] segment with different molecular weights and a hydrophobic polydimethylsiloxane (PDMS) segment were prepared as follows. The precursor copolymer poly(Boc-LysAA-OtBu-b-PDMS) was obtained from radical polymerization of N-α-acrylamide-N-ε-tert-butoxycarbonyl-L-lysine-tert-butylester (Boc-LysAA-OtBu) initiated with 4,4’-azobis(polydimethylsiloxane 4-cyanopentanoate) (azo-PDMS) with the molecular weight of PDMS Mw = 4.3 × 103 in the presence of 2-mercaptoethanol (2-ME) as a chain-transfer agent. Removal of the protecting groups of the precursor copolymer was carried out in 80% trifluoroacetic acid aqueous solution to give poly(LysAA-b-DMS)-1-3. The weight average molecular weight of poly(LysAA-b-DMS)-1-3 was Mw = 1.02 × 104 – 2.52 × 104. From the 1H-NMR and fluorescence spectra measurements, poly(LysAA-b-DMS)-1-3 was determined to self-organize and form core-shell micelles in water. The critical micelle concentration (CMC) increased to 1000 - 4000 mg·L–1 with increasing molar ratio of the poly(LysAA) segment from 0.42 to 0.65. From morphological analysis with a scanning probe microscope (SPM), poly(LysAA-b-DMS) has microphase-separated structures made up of hydrophilic and hydrophobic regions with the domain size ranging from several tens to several hundreds of nanometers. Inhibition of thrombin activity of poly(LysAA-b-DMS) was evaluated from the Michaelis constant (KM) and catalytic activity (kcat) for the enzymatic reaction of thrombin and synthetic substrate S-2238 in the presence of poly(LysAA-b-DMS). The KM and kcat were 0.10 - 0.11 mM and 4.04 × 105 – 4.26 × 105 min–1, respectively. Fibrinolytic activity was also verified from the transformation of plasminogen to plasmin by tissue plasminogen activator (t-PA) using synthetic substrate S-2251 in the presence of poly(LysAA-b-DMS). The KM and kcat were 0.07 mM and 5.73 × 106 –5.95 × 106 min–1, respectively.

温度敏感性PNIPAM-b-PZLL-b-mPEG三嵌段共聚物的合成与自组装研究

通过大分子引发剂引发ε-苄氧羰基-L-赖氨酸-N-羧酸酐(Lys-NCA)开环聚合和大分子缩合的方法合成了聚(N-异丙基丙烯酰胺)-b-聚(ε-苄氧羰基-L-赖氨酸)-b-聚乙二醇单甲醚三嵌段共聚物(PNIPAM-b-PZLL-b-mPEG).用GPC和1H-NMR对其结构进行了表征.用芘荧光探针法证明了该三嵌段聚合物形成胶束的性质并测定了临界胶束浓度(CMC).动态光散射(DLS)研究表明,在固定PNIPAM-b-PZLL链段长度的情况下,mPEG分子量为2000时,胶束在温度高于临界溶解温度(LCST)时发生聚集,mPEG分子量为5000时,胶束在LCST以上没有发生聚集.

冠心病患者血清晚期糖基化终产物N^ε-羧甲基赖氨酸含量的变化

目的 观察冠心病患者血清晚期糖基化终产物 (AGE)Nε 羧甲基赖氨酸 (CML)的水平。方法 采用抗戚蓝蛋白晚期糖基化终产物 (KLH AGE)抗体竞争ELISA法 ,对 33例冠心病患者、14例单纯高血压患者及 38名正常人血清中CML进行定量观察。结果 33例冠心病患者血清中均测得CML ,正常对照组中仅 3名血清CML含量 >0 .1mg/L ,两组比较差异有极显著性意义 (P <0 .0 0 1)。合并高血压的冠心病患者血清CML水平为 (0 .92± 0 .6 1)mg/L ,较单纯高血压 [(0 .2 3± 0 .16 )mg/L]或单纯冠心病 [(0 .44± 0 .47)mg/L]患者明显增高 (P <0 .0 1,P <0 .0 5 )。不合并糖尿病的冠心病患者和合并糖尿病的冠心病患者血清CML水平无显著差异。结论 冠心病患者血清CML水平明显增高 ,提示机体内晚期糖基化终产物的产生在冠状动脉粥样硬化的形成机制中可能起一定的作用。血清CML含量可作为冠心病患者晚期糖基化反应水平的生物学指标。

聚(N~ε-苄氧羰基赖氨酸)-聚乙二醇-聚(N~ε-苄氧羰基赖氨酸)的合成及其表征

利用三光气合成了Nε 苄氧羰基赖氨酸酸酐 (Lys(z) NCA) ,并用双端氨基聚乙二醇做引发剂 ,在DMF中引发Lys(z) NCA聚合 ,合成了聚 (Nε 苄氧羰基赖氨酸 ) 聚乙二醇 聚 (Nε 苄氧羰基赖氨酸 )三嵌段共聚物。利用IR、1HNMR、DSC和GPC对其结构进行了表征 ,结果表明 ,这种方法能够合成分子量可控、分子量分布窄 (Ip=1 0 6 )的嵌段共聚物 ,产率 95 4 %

两种N-保护赖氨酸的合成

L-赖氨酸盐酸盐与硫酸铜反应形成赖氨酸铜盐,继而与醋酐反应,得到Nε-乙酰基-赖氨酸铜盐,再利用H2S将铜脱去,最后用(Boc)2O或Fmoc-OSu保护α-氨基,得到Nε-乙酰基-Nε-叔丁氧羰基赖氨酸Boc-Lys(Ac)-OH(1)和Nε-乙酰基-Nε-芴甲氧羰基赖氨酸Fmoc-Lys(Ac)-OH(2).

LSD1、NDRG1基因沉默对人卵巢癌SKOV3细胞迁移能力的影响及两者的关系

目的观察赖氨酸特异性去甲基化酶1(LSD1)、N-myc下游调节基因1(NDRG1)基因沉默对人卵巢癌SKOV3细胞迁移能力的影响,并探讨两者的作用关系。方法取人卵巢癌SKOV3细胞株,通过shRNA方法建立诱导型干扰LSD1的SKOV3细胞株(LSD1-shRNA-SKOV3),将其分为对照组、Dox组、转染组和联合组。对照组用水处理,Dox组用100 ng/m L Dox处理,转染组转染NDRG1 siRNA,联合组转染NDRG1 siRNA的同时加入100 ng/m L Dox处理。采用实时荧光定量PCR和Western blotting法分别检测4组LSD1、NDRG1基因mRNA和蛋白表达;染色质免疫沉淀ChIP法和实时荧光定量PCR法分析对照组和Dox组NDRG1基因启动子区组蛋白H3第4位赖氨酸的二甲基化(H3K4me2)程度;Transwell小室测算4组细胞迁移率。结果 Dox组、转染组、联合组、对照组LSD1mRNA表达分别为0.407±0.029、0.936±0.024、0.413±0.018、0.941±0.035,蛋白表达分别为0.306±0.013、0.879±0.036、0.341±0.057、0.893±0.052,Dox组、联合组与对照组相比,P均<0.05。Dox组、转染组、联合组、对照组NDRG1 mRNA表达分别为0.791±0.045、0.107±0.016、0.165±0.021、0.239±0.027,蛋白表达分别为0.907±0.005、0.130±0.006、0.216±0.019、0.358±0.062,Dox组、转染组、联合组与对照组相比,联合组与Dox组、转染组相比,P均<0.05。Dox组、对照组细胞NDRG1基因启动子区H3K4me2水平分别为3.32±0.41、0.83±0.17,两组相比P<0.01。Dox组、转染组、联合组、对照组细胞迁移率分别为21.75%±1.816%、79.13%±2.561%、40.13%±2.039%、68.91%±3.167%,Dox组、转染组、联合组与对照组相比,联合组与Dox组、转染组相比,P均<0.05。结论 LSD1基因沉默人卵巢癌SKOV3细胞迁移能力降低,NDRG1基因沉默人卵巢癌SKOV3细胞迁移能力升高;LSD1通过降低NDRG1基因启动子区域H3K4me2水平,抑制NDRG1的表达,从而促进卵巢癌SKOV3细胞转移。

N-乙酰基-L-赖氨酸-甲酰胺对主链的理论构象分析

目的考虑到N-乙酰基-L-赖氨酸-甲酰胺的非键及静电相互作用、拓扑能、键角的弯曲和氢键,研究了它的空间结构即分析它的主链理论构象.方法当主链的最大构象可能性确定时,侧链的键角和两面角φ,ψ在每一点变化的情况下,用能量低化的方法得到了构象图,评价了主链和侧链的空间的相互制约性.当主链为低能式而侧链具有最大拓朴势时,φ,ψ,χ1-χ5角的所有组合作为初始近似的情况下,计算了分子的优势构象.结果N-乙酰基-L赖氨酸-甲酰胺的稳定构象与赖氨酸残基在蛋白质中的已知结构的几何构型相符合.

α,β-聚[(N-羟丙基/氨乙基)-DL-天冬酰胺-CO-L-赖氨酸]作为潜在的非病毒性基因载体的研究

实验研究了DL-天冬氨酸和L-赖氨酸通过不同的比例合成的一系列聚[DL-天冬氨酸-CO-L-赖氨酸](PAL),经过1H-NMR、FT-IR、X-Ray方法进行表征后确认了结构并证明该类聚合物有较好的规律性。PAL开环后合成α,β-聚[(N-羟丙基/氨乙基)-DL-天冬酰胺-CO-L-赖氨酸](PHAAL),通过对PHAAL在磷酸缓冲液(pH=7.4,0.01M)和酶(木瓜蛋白酶,胰蛋白酶)溶液中降解实验的研究,结果显示该类聚合物具有良好的降解能力。利用MTT方法测PHAAL在Hela,ECV-304,Bcap37细胞中的细胞毒性,实验结果表明PHAAL的细胞毒性较低。利用含溴乙啶(0.25μg/ml)的琼脂糖凝胶(1.0%,w/v)电泳检测PHAAL的DNA结合能力,发现赖氨酸聚合比例高的PHAAL结合DNA的能力较强。综合各种实验结果分析,PHAAL是一类可作为非病毒性基因载体的聚氨基酸类高分子材料。

糖尿病合并冠心病患者颈动脉粥样硬化斑块钙化的影响因素及其与血清Nε-羧甲基赖氨酸水平的相关性

目的探讨糖尿病合并冠心病患者血清Ne-羧甲基赖氨酸(CML)水平与颈动脉粥样硬化斑块钙化的相关性。方法选择2016年4月至2018年3月我院收治的糖尿病合并冠心病患者84例,进行颈部CT血管造影(CTA)检查,根据所评估血管是否发生钙化将其分为钙化组和无钙化组,收集两组患者临床资料,并检测血清CML水平,采用Logistic回归分析颈动脉粥样硬化斑块钙化影响因素和血清CML与颈动脉粥样硬化斑块钙化的相关性。结果颈动脉粥样硬化斑块钙化患者53例,无钙化患者31例。钙化组年龄、体质指数(BMI)、收缩压(SBP)、舒张压(DBP)、空腹血糖(FPG)、餐后2 h血糖(2hPG)、糖化血红蛋白(HbAlc)、血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)及CML水平均高于无钙化组(P <0. 05),高密度脂蛋白胆固醇(HDL-C)水平低于无钙化组(P <0.05)。多因素Logistic回归分析显示,年龄、糖尿病病程、冠心病病程、血清CML水平均是颈动脉粥样硬化斑块钙化发生的独立危险因素。结论糖尿病合并冠心病患者颈动脉粥样硬化斑块钙化影响因素包括年龄、糖尿病病程、冠心病病程、血清CML水平,其中血清CML水平异常升高与颈动脉粥样硬化斑块钙化发生密切相关。

N-乙酰基-L-赖氨酸-甲酰胺侧链构象的理论分析

目的分析N-乙酰基-L-赖氨酸-甲酰胺的非键和静电相互作用、拓朴能、键角的弯曲和氢键,研究它们的空间结构。方法当主链的最大构象可能性确定时,侧链的键角和两面角φ,ψ在每一点变化的情况下,用能量低化的方法得到了构象图,并评价了主链和侧链的空间的相互制约性。当主链为低能式而侧链具有最大拓朴势时,φ,ψ,χ_1-χ_5角的所有组合作为初始近似的情况下,计算了分子的优势构象.结果N-乙酰基-L-赖氨酸-甲酰胺的稳定构象与赖氨酸残基在蛋白质中的已知结构的几何构型相符合.结论赖氨酸残基在蛋白质中构象即为赖氨酸孤立单肽的优势构象。

3-N^ε-苄氧羰基赖氨酰基-吗啉-2，5-二酮的合成研究

以L-赖氨酸(L-Lysine)为原料合成了氨基酸类环化物单体——3-Nε-苄氧羰基赖氨酰基-吗啉-2,5-二酮。反应过程包括对ε-氨基的保护、乙酰化反应、分子内环化缩合反应。选择苄氧羰酰基(z)为ε-氨基的保护基团;三乙胺用作反应副产物溴化氢的中和剂。运用红外光谱(IR)、差示扫描量热法(DSC)、核磁共振(NMR)和元素分析等方法对产物的结构和性能进行了表征。通过分析测试证实了合成产物为3-Nε-苄氧羰基赖氨酰基-吗啉-2,5-二酮,产物熔点为254.5℃,构型为立体异构环状结构。

酶催化合成N-ε-油酰基赖氨酸产物中赖氨酸的分析

实验依据氨基酸与茚三酮显色反应的原理，建立了用分光光度法对酶催化合成N-ε-油酰基赖氨酸反应产物中赖氨酸质量浓度进行测定的方法，由此可计算得到赖氨酸的转化率。用3个样品分别进行4次重复测定，进行方法的精密度实验，其相对标准偏差分别是2.8%、3.1%和3.4%；用两个样品进行3次重复实验测定此方法的加标回收率，所得回收率在97%-110%，相对标准偏差分别为5.0%和5.6%。

Advanced glycation end products induce neural tube defects through elevating oxidative stress in mice

Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with com- mercial food containing 3% advanced glycation end product bovine serum albumin （AGE-BSA） or 3% bovine serum albumin （BSA） as a control. After mating mice, oxidative stress markers including malondialdehyde and H202 were measured at embryonic day 7.5 （E7.5） of ges- tation, and the level of intracellular reactive oxygen species （ROS） in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-（carboxymethyl） lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at El0.5 in embryos of mice fed with AGE-BSA （no hyperglycemia） compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-（carboxymethyl） lysine and N（ε）-（carboxyethyl） lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.

2型糖尿病合并冠心病患者血清中N-羧甲基赖氨酸水平的变化

目的观察糖尿病合并冠心病患者血清晚期糖基化终产物N-羧甲基赖氨酸(CML)水平与他去相关指标的关系。方法入选2型糖尿病合并冠心病患者68例,单纯2型糖尿病患者81例,单纯冠心病患者102例,正常对照者90例。测定各组血清CML、戊二醛(MDA)和其他常规生化指标。结果糖尿病合并冠心病患者体内的CML浓度明显高于单纯冠心病、单纯糖尿病和正常人(P<0.05),糖尿病时CML水平随冠心病的严重程度的增高而增加(P<0.05),CML与MDA水平在糖尿病合并冠心病组内存在相关性(均P<0.05)。结论 CML对预测糖尿病时冠心病及其严重程度具有一定的临床价值。

对二氧环己酮与N^ε-苄氧羰基-L-赖氨酸无规共聚物的合成及其共聚反应机理

通过对二氧环己酮与Nε-苄氧羰基-L-赖氨酸-N-羧酸酐本体共聚的方法制备了聚对二氧环己酮-Nε-苄氧羰基-L-赖氨酸的无规共聚物(PPCLAs),其结构1H NMR和GPC表征。考察了聚合反应时间及催化剂用量对PPCLAs平均分子量的影响,并提出了"先竞争引发,再大分子间缩聚"的共聚反应机理。