胸水GPDA、ADA及Tch联合检测的价值

[目的]探讨GPDA、ADA及Tch联合检测对胸水性质的鉴别诊断价值。[方法]66例胸水分为非结核性良性、结核性和恶性3组。同步检测胸水GPDA、ADA及Tch3项标记。[结果]胸水GPDA在结核性与恶性组明显高于非结核性良性组（P＜0.01）,ADA在结核组明显高于恶性与非结核良性组（P＜001）,Tch在结核性与恶性组明显高于非结核良性组（P＜0.01）。同步检测GPDA、ADA及Tch对非结核性良性、结核性和恶性胸水诊断的准确分别为93.9%、97.0%和93.9%。[结论]GPDA、ADA及Tch联合检测对鉴别良恶性胸水有重要参考价值。     

尿液甘氨酰脯氨酸二肽氨基肽酶测定及临床应用

目的　探讨尿液甘氨酰脯氨酸二肽氨基肽酶 (GPDA)测定及临床应用价值。方法　用连续监测法以甘氨酰脯氨酰对硝基苯胺为底物检测尿液GPDA ,并对检测条件及干扰因素进行试验探讨 ,同时对 334名正常人 ,5 5例糖尿病和 36例高血压患者尿液GPDA进行检测分析。结果　尿GPDA在 35 0U/L以下线性良好 ,低、高值尿液标本的批内变异系数 (CV)分别为 1 2 7%、0 6 1% ,批间CV为 1 33% ,尿液标本 4℃存放 7dGPDA活性没有变化 ,胆红素、葡萄糖、维生素C及糖尿病治疗药物二甲双胍、格列苯脲对GPDA测定无干扰 ,血红蛋白在 5 0 0mg/L以下时对GPDA测定无干扰 ,>5 0 0mg/L产生负干扰 ,334名正常人尿GPDA活性为 (12 9± 4 1)U/g·Cr,参考值范围 4 9～ 2 0 9U/g·Cr;糖尿病、高血压病合并肾损害组尿GPDA明显高于正常对照组和未发生肾损害组 ,差异有非常显著意义 (P <0 0 0 1)。结论　甘氨酰脯氨酸二肽氨基肽酶操作简单、快速、稳定性好 ,干扰因素少 ,结果准确 ,是诊断早期肾小管损伤的敏感而特异的检验项目。     

妊娠妇女血清亮氨酸氨基肽酶的水平变化及其临床意义

目的 探讨妊娠妇女血清亮氨酸氨基肽酶(LAP)的水平变化及其临床意义.方法 选取120例正常妊娠正常分娩的妇女作为正常妊娠组,根据其怀孕周数将其分为正常早期组、正常中期组与正常晚期组各40例;以28例患有妊娠期高血压的妇女作为妊高征组、26例出现早产的妇女为早产组、30例健康未妊娠妇女作为未妊娠组,检测各组妇女血清中的LAP水平.结果 未妊娠组、早产组、正常妊娠组、妊高征组的血清LAP水平依次升高(P<0.05).正常晚期组、正常中期组、正常早期组妇女的血清LAP水平依次降低(P<0.05),正常妊娠妇女的血清LAP水平与孕周呈正相关性(P<0.05).结论 妊娠妇女体内血清中LAP水平的变化存在着一定的规律,监测LAP水平对于评估妊娠期高血压疾病及早产的发生具有重要价值.     

木犀草素对脑胶质瘤细胞氨肽酶N活性影响

目的探讨木犀草素对脑胶质瘤细胞氨肽酶N活性影响机制。方法本研究采用酶抑制动力学方法, 研究了木犀草素对氨肽酶N的抑制作用、抑制类型和抑制动力学常数, 并进行了脑胶质瘤U87细胞的凋亡生长抑制试验。结果木犀草素能够诱导了脑胶质瘤U87细胞的凋亡, 并呈现一定的剂量依赖性, 当浓度≥10 μmol时, 与阳性对照bestatin 相比差异有统计意义(P<0.05), 求得半细胞凋亡率IC₅₀为(61.23±2.13)μmol;此外木犀草素是一种可逆的竞争型氨肽酶N抑制剂, 半抑制率IC₅₀为(70.85± 2.05)μmol, 抑制常数Ki为(24.83± 0.14)μmol;失活动力学时间进程分析表明,木犀草素能快速与氨肽酶N发生作用并迅速降低酶的活性。结论木犀草素是一个竞争性的氨肽酶N抑制剂, 使氨肽酶N的活性降低, 对诱导了脑胶质瘤U87细胞的凋亡起到重要作用。     

Decreased enkephalinase activity following postnatal treatment with phenobarbital

The effect of postnatal administration of phenobarbital on enzymes degrading enkephalin was examined. Daily subcutaneous injections (45 mg/kg) of phenobarbital were given to male and female rats from postnatal day 1 to 19. Brains from rats treated with saline and phenobarbital were used to prepare aminopeptidases (high speed supernatant) and enkephalinase A (synaptosomal membrane preparation). Incubation of methionine enkephaline (ME) with aminopeptidases from rat brain liberated tyrosine (T), while incubating with enkephalinase A resulted in the formation of tyrosylglycylglycin (TGG). Separation and quantification of tyrosine, tyrosylglycylglycin and methionine enkephalin was performed using a high performance liquid chromatograph, coupled to electrochemical and ultraviolet detectors in series. The treatment of the rats with phenobarbital resulted in a significant inhibition of enkephalinase A when measured in vitro, using methionine enkephalin as substrate. Preliminary studies with secobarbital show similar results to those obtained with phenobarbital.     

Buccal Absorption. III. Simultaneous Diffusion and Metabolism of an Aminopeptidase Substrate in the Hamster Cheek Pouch

The simultaneous diffusion and metabolism of the D- and L-isomers of the aminopeptidase substrate, leucine-p-nitroanilide (LPNA), were examined in vitro in the hamster cheek pouch. L-LPNA was completely hydrolyzed during diffusion across the cheek pouch, whereas D-LPNA crossed the cheek pouch intact. The metabolic barrier appeared to be localized in the epithelium of the cheek pouch. Addition of an aminopeptidase inhibitor, bestatin, to both diffusion cell reservoirs resulted in decreased hydrolysis of L-LPNA. The experimental results were analyzed with a mathematical model which was developed to describe the simultaneous diffusion and metabolism processes. Using this model it was estimated that the rate of diffusion of L-LPNA across the cheek pouch was less than the capacity of the tissue to hydrolyze L-LPNA.     

Aminopeptidase N in Sera of Healthy Subjects Is a Different N-Terminal Processed Derivative from the One Obtained from Maternal Serum

A major aminopeptidase present in normal human serum was purified to homogeneity as a 150-kDa molecular species. Western blotting confirmed the binding of an anti-aminopeptidase N antibody to the protein. The N-terminal amino acid sequence of the enzyme was determined. The first 13 amino acids of the enzyme completely matched amino acids 59–71 of the sequence predicted from the human intestinal aminopeptidase N cDNA nucleotide sequence. As reported previously, aminopeptidase N from maternal serum had 68 fewer amino acid residues at the N-terminus than the enzyme obtained from detergent-solubilized membranes. The results indicate that aminopeptidase N in normal serum is a different N-terminal processed derivative from that obtained from maternal serum.     

肥胖症儿童肝纤维化指标与血清GPDA活性变化的研究

目的 探讨肥胖症儿童肝纤维化指标透明质酸(HA)、层粘连蛋白(LN)、血清Ⅲ型前胶原肽(PCⅢ)、Ⅳ型胶原(CⅣ)与血清甘氨酰脯氨酸二肽氨基肽酶(GPDA)活性的变化及其在临床上的应用价值.方法 对2015年6月至2016年2月在丽水市妇幼保健院儿科门诊诊断为肥胖症的159例6 ～15岁肥胖症儿童(肥胖症组)和42例9～ 14岁正常健康儿童(正常对照组)进行肝纤维化指标与血清GPDA活性的比较,并对结果进行分析.结果 与正常对照组相比,肥胖症组HA、PCⅢ水平均明显升高(t值分别为7.403、5.405,均P＜0.05),以PCⅢ升高明显;肥胖症组GPDA活性差异有统计学意义(t=8.965,P＜0.01).肥胖症患儿治疗前后GPDA活性、HA及PCⅢ指标比较,各检测项目均出现降低,差异均有统计学意义(t值分别为6.452、5.684、4.369,均P＜0.05).PCⅢ与GPDA呈正相关(r=0.602,P＜0.05).结论 肥胖症儿童GPDA活性与PCⅢ水平的改变是其肝脏病变的早期敏感指标,两者的动态监测,对于诊断、疗效观察有一定的临床意义.     

Dipeptide Transport Across Rat Alveolar Epithelial Cell Monolayers

The transepithelial transport and metabolism of two model peptides, glycyl-D-phenylalanine (Gly-D-Phe) and glycyl-L-phenylalanine (Gly-L-Phe), across primary cultured monolayers of rat alveolar epithelial cells were studied. These tight monolayers (>2000 -cm²) exhibited type I pneumocyte morphological and phenotypic characteristics. A reverse-phase HPLC was used to monitor the appearance of parent dipeptides and their metabolites (D- or L-Phe) in the receiver fluid. The apparent permeability coefficient (P_app) for Gly-D-Phe was about 1.6 × 10^–7 cm/sec at both 1 and 10 mM and in both the apical-to-basolateral (AB) and the basolateral-to-apical (BA) directions. In contrast, the P _app of Gly-L-Phe at 1 mM was about two times higher than that at 10 mM in the AB direction. The P _app of Gly-L-Phe in the BA direction at either concentration was about the same (about 1.4 × 10^–7 cm/sec). Whereas no metabolite was detected during Gly-D-Phe transport, the proportions of a metabolite, L-Phe, observed at 4 hr in the basolateral receiver fluid for 1 and 10 mM apical donor Gly-L-Phe accounted for 83 and 77% of the estimated total Gly-L-Phe (i.e., L-Phe + Gly-L-Phe), respectively. The corresponding values in the BA direction were 40 and 19% of the estimated total Gly-L-Phe in the apical receiver reservoir. Metabolism of Gly-L-Phe was significantly reduced in the presence of 3 µM actinonin (an inhibitor relatively specific for aminopeptidase M) in the apical but not the basolateral fluid. Under all experimental conditions, the monolayers remained intact, as indicated by no appreciable changes in the bioelectric parameters of transepithelial potential difference and electrical resistance. The above data provide evidence for cellular metabolism of Gly-L-Phe as well as paracellular restricted diffusional transport of intact Gly-D-Phe and Gly-L-Phe and comparatively lower transcellular transport of Gly-L-Phe across the rat alveolar epithelial cell monolayer.