直接进样离子色谱法测定金银花中的4种阳离子含量

目的:建立直接进样离子色谱法测定中药金银花超声提取液中的Na+、K+、Ca2+、Mg2+4种阳离子的含量方法。方法:选用ICS-900离子色谱IonPac CS12A阳离子色谱柱,20mmol/L MSA等度淋洗脱,电导检测金银花中的4种阳离子。结果:Na+、K+、Ca2+、Mg2+的线性范围良好,最低检出限为0.020、0.025、0.015和0.050 mg/L,样品加样回收率介于97%~102%之间。结论:该法操作简便、快速、准确,为金银花中的Na+、K+、Ca2+、Mg2+含量测定提供了一种有效的方法。     

The urate-binding alpha 1-2 globulin. Isolation and characterization of the protein from human plasma

The urate-binding α_1–2 globulin has been isolated from human plasma in a highly purified state. The isolation procedure was based upon anion exchange chromatography of the plasma macromolecular fraction on DEAE-Sephadex columns followed by ammonium sulphate precipitations and preparative polyacrylamide gel electrophoresis. The urate-binding α_1–2 globulin is a rod-shaped glycoprotein with a molecular weight of 67000 as determined by dodecyl sulphate polyacrylamide gel electrophoresis and an isoelectric point of pH 4.6. In the presence of 6 N urea and mercaptoethanol respectively the protein does not split into subunits indicating that it might represent a single polypeptide chain. The urato-binding α_1–2 globulin contains 12.1% of carbohydrates including galactose, mannoso, galactosamine and sialic acid. The amino acid composition of the protein does not differ significantly from what is found in other plasma proteins except for the presence in automatic amino acid analysis of an hitherto unidentified compound. Further work is required in order to determine the number of binding sites for uric acid on the protein molecule.—The urate-binding α_1–2 globulin does not seem to be identical to any previously characterized protein from human blood.     

离子色谱法同时测定大气中NO_3~-和SO_4~(2-)的研究

目的建立大气中硝酸盐和硫酸盐同时分离测定的离子色谱分析方法。方法以超纯水超声浸提分离滤膜采集的气溶胶样品中阴离子,提取液经过简单过滤后,直接进样分析。选用高容量阴离子交换分析柱IonPac AS11-HC及其保护柱AG11-HC,以20.0mmol/L KOH作为淋洗液,以1.00ml/min的流速进行等度洗脱,抑制型电导检测,较好地完成了大气中硝酸盐和硫酸盐的含量测定。结果本方法线性良好,硝酸盐和硫酸盐测定的线性相关系数r≥0.9999,对大气中硝酸盐和硫酸盐含量分析的方法定量限分别为0.011和0.024μg/m3。样品中硝酸盐和硫酸盐的加标回收率为99.6%～105.6%,样品平行测定结果相对标准偏差RSD<3%。结论该方法操作简单、快速、准确、灵敏度高,适用于大气中硝酸盐和硫酸盐的测定。     

Pore-Forming Cardiotoxin VVA2 (Volvatoxin A2) Variant I82E/L86K Is an Atypical Duplex-Specific Nuclease

VVA2 (volvatoxin A chain 2) is a cardiotoxic protein purified from Volvariella volvacea. Its biological activities include hemolysis, writhing reaction, neurotoxicity, and ventricular systolic arresting activity. The cytotoxicity of VVA2 was mainly considered due to its pore-forming activity. Here we report a novel biological activity of its variants VVA2 I82E/K86K as a duplex-specific nuclease. Recombinant VVA2 variant I82E/L86K (Re-VVA2 I82E/L86K), deprived of the oligomerization property, shows increased nuclease activity compared to VVA2. Re-VVA2 I82E/L86K converts supercoiled DNA (Replicative form I, RF I) into nicked form (RF II) and linear form (RF III) in the presence of Mg²⁺ or Mn²⁺. Besides plasmid DNA, it also exhibits nuclease activity on E. coli genomic DNA rather than ssDNA or RNA. Re-VVA2 I82E/L86K preferentially cleaves dG-dC-rich dsDNA regions and shows the best performance at pH 6–9 and 55 °C. Our structure–function study has revealed amino acid E111 may take an active part in nuclease activity through interacting with metal ions. Based on the sequences of its cleavage sites, a “double-hit” mechanism was thereby proposed. Given that Re-VVA2 I82E/L86K did not exhibit the conserved nuclease structure and sequence, it is considered an atypical duplex-specific nuclease.     

Plasma Nitrate and Nitrite Kinetics after Single Intake of Beetroot Juice in Adult Patients on Chronic Hemodialysis and in Healthy Volunteers: A Randomized,Single-Blind,Placebo-Controlled,Crossover Study

Nitric oxide (NO) contributes to maintaining normal cardiovascular and renal function. This bioactive signalling molecule is generally formed enzymatically by NO synthase in the vascular endothelium. NO bioactivity can also be attributed to dietary intake of inorganic nitrate, which is abundant in our diet, especially in green leafy vegetables and beets. Ingested nitrate is reduced to nitrite by oral commensal bacteria and further to NO systemically. Previous studies have shown that dialysis, by means of removing nitrate and nitrite from the body, can reduce NO bioactivity. Hence, dietary intervention approaches aimed to boost the nitrate–nitrite–NO pathway may be of benefit in dialysis patients. The purpose of this study was to examine the kinetics of plasma nitrate and nitrite after a single intake of nitrate-rich concentrated beetroot juice (BJ) in adult hemodialysis (HD) patients and in age-matched healthy volunteers (HV). Eight HD patients and seven HV participated in this single center, randomized, single-blind, placebo-controlled, crossover study. Each participant received a sequential single administration of active BJ (70 mL, 400 mg nitrate) and placebo BJ (70 mL, 0 mg nitrate) in a random order separated by a washout period of seven days. For the kinetic analysis, blood samples were collected at different time-points before and up to 44 h after BJ intake. Compared with placebo, active BJ significantly increased plasma nitrate and nitrite levels both in HD patients and HV. The area under the curve and the maximal concentration of plasma nitrate, but not of nitrite, were significantly higher in HD patients as compared with HV. In both groups, active BJ ingestion did not affect blood pressure or plasma potassium levels. Both BJs were well tolerated in all participants with no adverse events reported. Our data provide useful information in planning dietary nitrate supplementation efficacy studies in patients with reduced NO bioactivity.     

Photoreduction of Copper Ions Using Silica–Surfactant Hybrid and Titanium (IV) Oxide under Sulfuric Acid Conditions

Photoreduction of Cu²⁺ ions to Cu metal by titanium(IV) oxide (TiO₂) was conducted in the presence of a silica–surfactant hybrid under sulfuric acid conditions. After irradiation, a dark-red color, reflections due to Cu metal in the X-ray diffraction pattern, and peaks due to Cu 2p_1/2 and 2p_3/2 in the X-ray photoelectron spectrum indicated the precipitation of Cu metal in the product. In addition, an increase in the Brunauer–Emmett–Teller specific surface area from 36 and 45 m²/g for the silica–surfactant and TiO₂, respectively, to 591 m²/g for the product, and a decrease in the intensity of the C-H stretching band in the Fourier–transform infra-red spectra implied the removal of surfactant during the reaction. These characteristics were never observed when TiO₂ was used solely. Therefore, this study indicated that the photoreduction of Cu²⁺ ions to Cu metal by TiO₂ was facilitated under the sulfuric acid medium, where the surfactants extracted from silica–surfactant hybrids by protons in the acidic condition were successfully photo-oxidized by TiO₂. Thus, this study presents a new application of the conversion of a silica–surfactant hybrid into mesoporous silicas.     

Intactness of membranous structure in canine stunned myocardium shown with colloidal lanthanum nitrate

ＩｎｔａｃｔｎｅｓｓｏｆｍｅｍｂｒａｎｏｕｓｓｔｒｕｃｔｕｒｅｉｎｃａｎｉｎｅｓｔｕｎｎｅｄｍｙｏｃａｒｄｉｕｍｓｈｏｗｎｗｉｔｈｃｏｌｌｏｉｄａｌｌａｎｔｈａｎｕｍｎｉｔｒａｔｅＺｈｕＹｏｎｇｈｏｎｇ（朱永宏），ＬｉＬａｎｓｕｎ（李兰荪），Ｃｈｅｎ...     

重离子治疗恶性肿瘤对机体免疫功能的影响

目的 通过检测患者免疫球蛋白、T细胞亚群及NK细胞的变化.探讨重离子放射治疗恶性肿瘤是否对机体免疫功能产生影响.方法 将26例经病理学证实的恶性肿瘤患者采用重离子束局部外照射,在治疗前后分别取患者外周血,采用化学发光法,用全自动生化分析仪测定血清IgG、IgA、IgM的量,用流式细胞仪检测放疗前后T细胞亚群及NK细胞比例.结果 NK细胞、CD4^＋ T细胞、CD8^＋T细胞及CD4^＋ T/CD8^＋T在治疗前后无明显变化,免疫球蛋白IgG、IgA、IgM在治疗前后无明显变化.结论 重离子治疗对免疫功能无明显影响.     

离子法测定中蒙药材苦杏仁中六种阴离子的含量

目的: 建立一种同时测定中蒙药苦杏仁药材中F^－、Cl^－、Br^－、NO^－₃ 、SO2^－₄ 、PO^3－₄ 阴离子的含量测定方
法。方法:采用离子色谱法、阴离子色谱柱、氢氧化钠梯度淋洗、电导检测苦杏仁6 种无机阴离子。结果: F^－、
Cl^－、Br^－、NO^－₃ 、SO₂^－4 、PO^3－₄ 的加样回收率介于97%～ 102%,苦杏仁中F－、Cl－、Br－、NO－3 、SO2－4 、PO3－
4 重复性良好,含量分别为0．057%0．084%,0．063%,0．070%,0．30%,0．12%。结论: 离子色谱法可以同时检测苦杏仁中6 种阴离
子,灵敏度高,结果准确可行,为苦杏仁的质量控制提供了一种简便快速的方法．