Renal urate transport during variations in urate synthesis in the rat

Summary In order to determine the effect of intrarenal synthesis of urate upon the urinary urate excretion in the rat, we effected large changes in urate synthesis by increasing it with hypoxanthine and decreasing it with allopurinol. Hypoxanthine infusion increased plasma urate rapidly and also increased the urinary urate excretion and its renal clearance. However, when the plasma urate was maintained constant, hypoxanthine had no effect upon renal urate transport. Conversely, allopurinol infusion rapidly diminished the plasma urate, urinary urate excretion and its renal clearance. Again, the maintenance of a constant plasma urate concentration prevented any change in urate transport during allopurinol. The urinary degradative purine metabolite pattern was altered pre-dictably by hypoxanthine and allopurinol. Assuming that any putative intrarenal component of urate synthesis would be affected predictably and consistently by hypoxanthine and allopurinol, these results suggest that changes in intrarenal urate synthesis are not an important determinant of urate excretion in the rat.Reported in abstract form in Clinical Research23, 508 A (1975)     

Handling of allantoin by the rat kidney

Summary Renal excretion of allantoin was measured by tracer techniques. After injection of 2-C14 urate and H3 inulin, clearances of allantoin and inulin were measured and both proximal and distal tubules were micropunctured.In confirmation of earlier results 2-C14 urate injected into an intact animal is very rapidly converted to C14 allantoin: after 15 min more than 90% of urinary tracer is present as allantoin. It was further observed that 1) allantoin clearance is essentially identical with inulin clearance over a wide range of urine flows; 2) no net transport of allantoin occurs in either proximal or distal tubules. Clearly allantoin is handled by the rat kidney like inulin.The total excretion of filtered allantoin unlike that of filtered urate provides an easy and effective mechanism for animals possessing the enzyme uricase to dispose of their purine loads.Partially supported by the Österreichischer Fonds zur Förderung der wissenschaftlichen Forschung.Receiving scholarships from Deutsche Forschungsgemeinschaft.     

Anti-HIV-1 integrase compounds from Dioscorea bulbifera and molecular docking study

Context Dioscorea bulbifera L. (Dioscoreaceae) has been used in a traditional Thai longevity medicine preparation. Isolation of inhibitors from natural products is a potential source for continuous development of new HIV-1 integrase (IN) inhibitors.

Objective The objective of this study is to isolate the compounds and evaluate their anti-HIV-1 IN activity, as well as to predict the potential interactions of the compounds with an IN.

Materials and methods The ethyl acetate and water fractions (1–100?μg/mL) of Dioscorea bulbifera bulbils were isolated and tested for their anti-HIV-1 IN activity using the multiplate integration assay (MIA). The interactions of the active compounds with IN were investigated using a molecular docking method.

Results and discussions The ethyl acetate and water fractions of Dioscorea bulbifera bulbils afforded seven compounds. Among these, allantoin (1), 2,4,3′,5′-tetrahydroxybibenzyl (2), and 5,7,4′-trihydroxy-2-styrylchromone (5) were isolated for the first time from this plant. Myricetin (4) exhibited the most potent activity with an IC₅₀ value of 3.15?μM, followed by 2,4,6,7-tetrahydroxy-9,10-dihydrophenanthrene (3, IC₅₀ value=?14.20?μM), quercetin-3-O-β-d-glucopyranoside (6, IC₅₀ value?=?19.39?μM) and quercetin-3-O-β-d-galactopyranoside (7, IC₅₀ value?=?21.80?μM). Potential interactions of the active compounds (3, 4, 6, and 7) with the IN active site were additionally investigated. Compound 4 showed the best binding affinity to IN and formed strong interactions with various amino acid residues. These compounds interacted with Asp64, Thr66, His67, Glu92, Asp116, Gln148, Glu152, Asn155, and Lys159, which are involved in both the 3′-processing and strand transfer reactions of IN. In particular, galloyl, catechol, and sugar moieties were successful inhibitors for HIV-1 IN.     

奥特拉西的合成及光谱测定

目的:合成奥特拉西并改进合成工艺.方法:以尿囊素为原料,在碱性条件下以溴素为氧化剂,一步反应制得奥特拉西.结果和结论:所得产物经元素分析、紫外光谱、红外光谱、核磁共振谱及质谱等确证结构,说明此合成方法是可行的.     

HPLC法测定日本薯蓣中尿囊素的含量

目的:建立测定日本薯蓣中尿囊素含量的方法,并比较日本薯蓣与山药中尿囊素的含量。方法:采用高效液相色谱法。色谱柱为Kromasil C18(250mm×4.6mm,5μm),流动相为甲醇-水(2:98),流速为0.8mL·min-1,检测波长为224nm,柱温为30℃。结果:尿囊素进样量在0.355～4.260μg范围内与峰面积积分值呈良好线性关系(r=0.9998);平均加样回收率为98.77%,RSD=1.49%(n=6)。日本薯蓣明显高于山药中尿囊素的含量。结论:该方法可作为日本薯蓣中尿囊素的含量测定方法。     

痤疮霜中尿囊素的薄层色谱测定法

用双波长薄层扫描法对尿囊素的含量测定进行了研究，回收率１００．７％，ＲＳＤ１．４２％，ｒ＝０．９９９表明本法能避免其它成分的干扰，结果准确、简单、实用。     

HPLC同时测定参苓白术胶囊中的5种有效成分

目的 采用HPLC法同时测定参苓白术胶囊中5种有效成份的含量.方法 采用梯度洗脱法测定制剂中去氢土莫酸、猪苓酸C、茯苓酸、薯蓣皂苷元和尿囊素的含量.结果 5.27～105.40 μg· mL-1(r=0.9998)去氢土莫酸、4.30 ～ 86.00 μg·mL-1(r =0.9995)猪苓酸C、5.25 ～105.00μg·mL-1(r=0.9997)茯苓酸、4.26～85.20 μg· mL-1(r=0.9994)薯蓣皂苷元和6.91 ～ 138.20 μg· mL-1(r=0.9999)尿囊素与其峰面积呈良好的线性关系;平均加样回收率分别为97.77％、97.27％、98.13％、96.93％、99.37％,RSD分别为1.42％、1.07％、0.96％、1.10％、0.56％(n=6).结论 所用方法简便、快捷、重复性好,可用于该制剂的质量控制.     

无硫山药饮片加工工艺优选

目的:优选无硫山药饮片最佳梯度干燥工艺,为无硫山药饮片的加工提供技术参数。方法:用紫外分光光度法和高效液相色谱法分别测定山药中多糖和尿囊素含量。以多糖和尿囊素含量为指标,采用正交试验和单因素试验法优选山药饮片梯度干燥工艺。结果:梯度干燥Ⅰ阶段最佳加工工艺为A2B2,即115℃干燥60 min;梯度干燥Ⅱ阶段最佳干燥温度为65℃。结论:优选得到的工艺稳定可行,可作为无硫山药饮片加工工艺。     

“安乐漱口散”治疗牙周病和复发性口腔溃疡的临床疗效观察

安乐漱口散是以尿囊素为主要成份的新型制剂，它能随溶液渗入龈沟、牙周袋及一些不便用药的部位（舌、软腭等）．安乐漱口散治疗牙周炎和缘龈炎的显效率分别为８１．２５％和５６．８６％，治疗复发性口腔溃疡有效率为６８．５７％     

RP-HPLC法同时测定复方维A酸乳膏中尿囊素、维A酸、异维A酸和维生素E的含量

目的:建立同时测定复方维A酸乳膏中尿囊素、维A酸、异维A酸和维生素E含量的方法。方法:采用反相高效液相色谱法。色谱柱为ODS Syncronis C18,流动相为甲醇-水-0.5%冰醋酸(梯度洗脱,采用不同的流速和检测波长),进样量为20μl,柱温为35Ⅴ。结果:尿囊素、维A酸、异维A酸、维生素E的检测质量浓度分别在125² 000、12.52 000、12.5²00、6.25200、6.25¹00、250100、250⁴ 000μg/ml范围内与各自峰面积积分值呈良好的线性关系(r=0.999 8、0.999 9、0.999 8、0.999 9);精密度、稳定性、重复性试验的RSD≤0.88%;平均加样回收率分别为99.5%、97.6%、99.8%、99.0%,RSD分别为0.24%、0.97%、0.18%、0.72%(n=6)。结论:该方法操作简便、快速、准确,适用于同时测定复方维A酸乳膏中尿囊素、维A酸、异维A酸和维生素E的含量。