固相萃取HPLC法测定豆芽中4-氯苯氧乙酸钠

目的:建立固相萃取HPLC法测定豆芽中4-氯苯氧乙酸钠残留的检测方法。方法:豆芽样品经稀碱提取后,用50%的H3PO4溶液调至酸性,经OasisR○HLB柱富集,甲醇洗脱。以甲醇+0.01 mol/L磷酸盐缓冲液(40+60)为流动相,采用ZORBAX SB C18柱(250 mm×4.6 mm×5μm)分离,UV 228 nm检测,外标法定量。结果:豆芽中4-氯苯氧乙酸钠的线性范围在0.20~6.0 mg/L,回收率在92.0%~95.0%,RSD均小于6%,最低定量检出限为0.04 mg/kg。结论:该方法具有快速、灵敏、简便、准确等优点,能满足实际工作的需要。     

针刺益气养阴活血法治疗糖尿病周围神经病变机制的实验研究

目的:探讨针刺对糖尿病大鼠周围神经病变的治疗作用和机制。方法:对链脲佐菌素(STZ)诱导的糖尿病大鼠取穴脾俞、肾俞、三阴交、足三里,隔日针刺1次,每次30 min,针刺治疗8周后测定大鼠感觉神经传导速度(SNCV)、热痛域,坐骨神经能够内山梨醇、一氧化氮(NO)和Na -K -ATPase活性。结果:糖尿病大鼠SNCV明显减慢,热痛域值明显升高;坐骨神经内山梨醇升高、NO降低,Na -K -ATPase活性降低,与正常组比较差异显著(P<0.05或0.01)。针刺治疗可使上述改变减轻,与糖尿病模型组比较差异显著(P<0.05或0.01)。结论:针刺治疗通过降低实验性糖尿病大鼠坐骨神经内山梨醇含量,防止NO降低和Na -K -ATPase活性下降,可有效恢复其神经传导速度、热痛域等神经障碍,为治疗DPN的有效方法。     

The interactions of phenytoin and its binding site in DI‐S6 segment of Na+ channel voltage‐gated peptide by NMR spectroscopy and molecular modeling study

Abstract: Nuclear magnetic resonance (NMR) spectra of a model peptide (BL‐DIS6), in the presence of anticonvulsant diphenyl drug, phenytoin (DPH), were measured to obtain the interactions between the selected drug and the model peptide. BL‐DIS6's sequence corresponds to the S6 segment in domain I of rat brain type IIA Na⁺‐channel. NMR studies have demonstrated that the magnitude of the chemical shifts of amide‐ and α‐protons can be used as a measurement of the complex stability and binding site of the peptide. Our NMR results propose a 3₁₀‐helical structure for BL‐DIS6, and suggest a binding cavity for DPH that involves the hydrophobic particles of residues Ans‐7, Leu‐8, Val‐11, and Val‐12. Furthermore, molecular modeling was performed to provide a possible complex conformation that the phenyl portion of DPH is accommodated in the proximity of the C‐terminal residues Ala‐11 and Val‐12, and simultaneously the heterocyclic amine ring of DPH is perching at the residue Asn‐7 periphery and stabilizing the phenyl portion deep insertion into the peptide.     

周络通对糖尿病周围神经病变大鼠坐骨神经功能影响

目的:研究周络通(黄芪,桂枝,当归,生地,细辛等)对链脲佐菌素(STZ)糖尿病大鼠坐骨神经功能和多元醇代谢通路的影响.方法:动物ig给药,连续8周,观察药物对链脲佐菌素糖尿病大鼠坐骨神经形态学改变、神经传导速度、坐骨神经Na ,K -ATP酶和醛糖还原酶活性及山梨醇、肌醇、果糖、葡萄糖、甘露糖等多元醇含量的影响.结果:周络通对链脲佐菌素糖尿病大鼠坐骨神经形态学改变有明显保护作用,坐骨神经传导速度明显性提高,Na ,N -ATP酶活性增强、醛糖还原酶活性降低,山梨醇、葡萄糖含量降低.结论:周络通可改善糖尿病大鼠周围神经组织的代谢,改善神经组织功能,对STZ糖尿病大鼠周围神经病变具有防治作用.     

不同厂家的银杏叶制剂对冷水负重游泳模型小鼠保护作用的比较研究

目的观察不同厂家银杏叶制剂(天保宁片和金纳多片)对冷水负重游泳模型小鼠的保护作用.方法小鼠8℃冷水负重游泳5min,测定模型小鼠的断头喘气持续时间,并采用分光光度法测定其脑组织生化代谢的改变.结果与空白对照组相比,模型小鼠脑组织乳酸(LA)含量明显增加,乳酸脱氢酶(LDH)、Na -K -ATP酶、Ca2 -Mg2 -ATP酶活力明显降低(P＜0.01);而2个EGB组均可以明显逆转模型小鼠上述生化指标的改变(P＜0.05,P＜0.01).结论不同厂家生产的EGB制剂均对冷水负重游泳模型动物具有保护作用,且在对模型小鼠脑组织生化代谢的影响上未显示出明显差异,故均可以作为耐缺氧研究的阳性药物.     

龙眼参对小鼠化学性肝损伤的保护作用及其机制研究

目的 :研究龙眼参对小鼠化学性肝损伤的保护作用及其机制。方法 :分别对四氯化碳、硫代乙酰胺和对乙酰氨基酚所致小鼠化学性肝损伤模型进行分组对照实验 ,并对各项相关指标进行测定和比较。结果 :与模型组比较 ,龙眼参治疗组ALT活性明显降低 ;肝脏细胞色素P450 及细胞色素b5 含量升高 ;肝组织丙二醛的含量显著降低 ;苯胺羟化酶及氨基比林 -N -去甲基酶活性增强 ;肝微粒体Ca2 + -ATP酶的活性明显降低 ;谷胱甘肽及谷胱甘肽过氧化物酶的水平明显提高。结论 :龙眼参对小鼠化学性肝损伤具有保护作用 ,其机制可能与其抗氧自由基、抑制脂质过氧化、诱导肝药酶活性和阻滞Ca2 +通道的作用有关。     

Study of effect of oxygen／glucose-deprived culture on the brain-pancreas relative protein in PC12 cells and the mechanism

AIM: To study the effect of oxygen/glucose-deprived (OGD)culture on the expression of a novel protein, brain-pancreas relative protein (BPRP), and the possible regulating mechanism in vitro. BPRP was a key protein found in our previous study of cerebral ischemia. METHODS: PC12 cells was selected and exposed to the Eagle‘s solution containing 1 mmol/L Na2S2O4 for     

Distal Convoluted Tubule

The distal convoluted tubule is the nephron segment that lies immediately downstream of the macula densa. Although short in length, the distal convoluted tubule plays a critical role in sodium, potassium, and divalent cation homeostasis. Recent genetic and physiologic studies have greatly expanded our understanding of how the distal convoluted tubule regulates these processes at the molecular level. This article provides an update on the distal convoluted tubule, highlighting concepts and pathophysiology relevant to clinical practice.     

Quantitative susceptibility mapping and 23Na imaging‐based in vitro characterization of blood clotting kinetics

Blood clotting is a fundamental biochemical process in post‐hemorrhagic hemostasis. Although the varying appearance of coagulating blood in T₁‐ and T₂‐weighted images is widely used to qualitatively determine bleeding age, the technique permits only a rough discrimination of coagulation stages, and it remains difficult to distinguish acute and chronic hemorrhagic stages because of low T₁‐ and T₂‐weighted signal intensities in both instances. To investigate new biomedical parameters for magnetic resonance imaging‐based characterization of blood clotting kinetics, sodium imaging and quantitative susceptibility mapping (QSM) were compared with conventional T₁‐ and T₂‐weighted imaging, as well as with biochemical hemolysis parameters. For this purpose, a blood‐filled spherical agar phantom was investigated daily for 14 days, as well as after 24 days at 7 T after initial preparation with fresh blood. T₁‐ and T₂‐weighted sequences, a three‐dimensional (3D) gradient echo sequence and a density‐adapted 3D radial projection reconstruction pulse sequence for ²³Na imaging were applied. For hemolysis estimations, free hemoglobin and free potassium concentrations were measured photometrically and with the direct ion‐selective electrode method, respectively, in separate heparinized whole‐blood samples along the same timeline. Initial mean susceptibility was low (0.154 ± 0.020 ppm) and increased steadily during the course of coagulation to reach up to 0.570 ± 0.165 ppm. The highest total sodium (NaT) values (1.02 ± 0.06 arbitrary units) in the clot were observed initially, dropped to 0.69 ± 0.13 arbitrary units after one day and increased again to initial values. Compartmentalized sodium (NaS) showed a similar signal evolution, and the NaS/NaT ratio steadily increased over clot evolution. QSM depicts clot evolution in vitro as a process associated with hemoglobin accumulation and transformation, and enables the differentiation of the acute and chronic coagulation stages. Sodium imaging visualizes clotting independent of susceptibility and seems to correspond to clot integrity. A combination of QSM and sodium imaging may enhance the characterization of hemorrhage.     

镁离子在治疗心律失常中的研究进展

Mg^2＋是人体内重要的电解质离子，是人体细胞内含量第二丰富的阳离子，具有复杂的调节机制，对维持机体新陈代谢及其他生理功能具有极其重要的作用。目前已发现人体内超过300种酶的作用离不开其参与，其中包括Mg^2＋-K^＋-ATP酶、Ca^2＋-ATP酶等。临床上利用Mg^2＋调节这些酶的活性等特点，将Mg^2＋作为一种预防和治疗心律失常的药物在很多方面运用，但其规范化运用仍有待进一步明确。现将Mg^2＋在心律失常中的运用综述如下。