兔中性粒细胞防御素对HL—60细胞毒性及对病毒的直接灭活作用

本研究从新西兰家兔腹腔渗出中性粒细胞溶酶体内提取酸溶性组分，经制备性ＡＵ－ＰＡＧＥ获得纯化的防御素（ＮＰ１和ＮＰ２），ＳＤＳ－ＰＡＧＥ测定分子量为３ｋｄ左右。以ＨＬ－６０细胞作靶细胞，当ＮＰ１或ＮＰ２在１００μｇ／ｍｌ浓度时，可杀死６０％以上的ＨＬ－６０细胞。ＮＰ１（２６０μｇ／ｍｌ）还可直接灭活单纯疱疹病毒Ｉ型和乙型流感病毒，分别使病毒感染滴度降度９８．２％和９０％。本研究结果提示，中性粒细胞可     

An unidentified macromolecular inhibitory constituent of calcium oxalate crystal growth in human urine

Summary We have detected and isolated a macromolecular constituent in normal human urine possessing calcium crystal growth inhibitory activity. The purification procedure consisted of two anion exchange chromatographies and one affinity chromatography. The crystal growth inhibitor was found to be heterogeneous in net charge as well as in size. It has not been identified. It is not an uronic acid-containing glycosaminoglycan, hitherto presumed to be responsible for the inhibitory activity. Whether an urinary fragment of inter--trypsin inhibitor is responsible has yet to be resolved.     

吡啶斯的明试验对评价垂体hGH储备功能的价值

垂体hGH分泌受中枢神经介质调控。兴奋胆碱能系统可使hGH增加。本文试用胆碱酯酶抑制剂吡啶斯的明兴奋hGH,并与胰岛素兴奋试验进行比较,观察了13名正常青少年和10名垂体性侏儒症患者对两种兴奋试验的反应。结果显示口服吡啶斯的明2mg/kg体重能迅速有效地兴奋垂体hGH释放。其作用较胰岛素兴奋试验更强,是一项值得推荐的判定青少年垂体hGH储备功能的试验。     

红细胞膜钙内流和钙泵活性在慢性肾功能不全时的变化及其氨氯地平的干预

为了探讨红细胞膜Ca运转对慢性肾功能不全的影响,我们应用放射性同位素~(45)Ca示踪技术对15例慢性肾功能不全者进行红细胞膜钙内流(Ecc)及钙泵活性(Ecp)检测,并使用氨氯地平进行干预,结果发现:①慢性肾功能不全Ecc高于正常组;Ecp低于正常组。②经氨氯地平5～10mg每日1次干预4～6周后检测,Ecc下降,Ecp升高。BUN、Cr、24h尿蛋白均改善,初步显示了氨氯地平延缓肾衰进展的效果。     

ZS-B型离心泵临床研究

目的 对ＺＳ－Ｂ型离心泵与Ｓａｒｎｓ离心泵进行比较,评价ＺＳ－Ｂ型离心泵的性能。方法 将１８例病人分为：Ａ组（１０例）使用ＺＳ０Ｂ型离心泵进行体外循环,Ｂ组（８例）使用Ｓａｒｎｓ离心泵进行体外循环。分别于术前,体外循环结束时,体外循环结束后１ｈ、２ｈ、２４ｈ、４８ｈ抽血查血细胞比容、游离血红蛋白、红细胞和血小板。于术前、体外循环结束后１２ｈ、２４ｈ、４８ｈ测定尿蛋白。结果 两缄体外循环结束后,血细     

Spike protein mediated membrane fusion during SARS-CoV-2 infection

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed a serious threat to public health and has quickly become a global concern. The infection of SARS-CoV-2 begins with the binding of its spike protein to the receptor-angiotensin-converting enzyme 2 (ACE2), which, after a series of conformation changes, results in the fusion of viral-cell membranes and the release of the viral RNA genome into the cytoplasm. In addition, infected host cells can express spike protein on their cell surface, which will interact with ACE2 on neighboring cells, leading to cell membrane fusion and the formation of multinucleated cells or syncytia. Both viral entry and syncytia formation are mediated by spike-ACE2 interaction and share some common mechanisms of membrane fusion. Here in this review, we will summarize our current understanding of spike-mediated membrane fusion, which may shed light on future broad-spectrum antiviral development.     

人工心脏圆盘泵的流动特性研究

人工心脏（血泵）一直存在泵体对血细胞剪切力过大和流速过快容易引起溶血的问题。为了研究人体正常血压情况下,血泵内部剪切力和速度场的分布情况,选择圆盘泵叶轮代替传统离心泵叶轮,对两种模型进行数值计算,分析不同叶轮内部剪切力和速度场的分布规律。研究表明传统离心泵内部流速高,叶片表面剪切力大,对血细胞的伤害大。圆盘泵相比传统离心泵,剪切力更小,流场速度分布均匀,流速更小。和传统离心泵相比,不同转速下圆盘泵能降低溶血的发生率。圆盘泵叶片数为6片时,抗溶血性能更好。研究结果为血泵的优化提供理论依据。     

Rat Jejunal Permeability and Metabolism of μ-Selective Tetrapeptides in Gastrointestinal Fluids from Humans and Rats

Purpose. To study intestinal transport and metabolism of three new -selective tetrapeptide enkephalin analogues, LEF537, LEF553 and TAPP These peptides are stabilized against enzymatic hydrolysis by having a D-aminoacid in position 2 and a blocked COOH-terminal. Methods. We used a single-pass perfusion technique to study the transport of the peptides in rat jejunum. To reduce luminal and/or brush-border metabolism during the perfusion we used protease inhibitors (Pefabloc^® SC, bestatin and thiorphan). The rate of metabolism was studied by incubations in rat jejunal homogenate, rat jejunal fluid and human gastric and jejunal fluid with and without these inhibitors. Results. The jejunal permeabilities (P_eff) of the peptides were 0.43–0.78 10^–4 cm/s without inhibitors and 0.09–0.45 10^–4 cm/s in presence of the inhibitors. All three peptides were rather rapidly degraded by enzymes in rat jejunal homogenate with half-lives of between 11.9 ± 0.5 and 31.7 ± 1.5 min. The addition of inhibitors to the homogenate prolonged the half-lives substantially for LEF553 (167 ± 35 min) and TAPP (147 ± 2 min), but only slightly for LEF537 (16.4 ± 0.5 min). LEF553 and TAPP were both hydrolyzed in rat and human jejunal fluid, while LEF537 was metabolized less in these fluids. When LEF553 and TAPP were incubated with intestinal fluid in the presence of inhibitors, metabolism was almost completely inhibited. There was no metabolism for any of the peptides in human gastric juice. Conclusions. The replacement of the terminal free carboxylic group with an amide group did not increase the stability of the peptides in jejunal tissue enough to allow successful oral drug delivery.