Interactions of small polypeptides with dimyristoylphosphatidylcholine monolayers: effect of size and hydrophobicity

The effects of size and hydrophobicity of small (molecular weights below 2,000) polypeptides on their predominantly hydrophobic interactions with a neutral phospholipid monolayer were studied. The changes in surface pressure were determined when various concentrations of Gly, Gly-Gly-Gly, -Ala, -Ala- -Ala- -Ala, -Ala-Gly-Gly-Gly-Gly, -Phe- -Leu- -Glu- -Glu- -Leu, adrenocorticotropic hormone fragments 1–10 (ACTH-(1–10)), porcine β-lipotropin, -endorphin and human fibrinopeptide A were injected under dimyristoylphosphatidylcholine (DMPC) monolayers at an initial surface pressure of 10 dyne/cm. In all cases, when peptides with the same number of residues are compared, the concentration needed to increase the surface pressure of the film by 1 dyne/cm was inversely related to its hydrophobicity. A reasonably good correlation was found to exist between the calculated free energy of transfer of a polypeptide from ethanol to water (a measure of its hydrophobicity) and its ability to increase the surface pressure of the DMPC film (a measure of the extent of its interaction with the neutral lipid monolayer).     

铁骨晶对大鼠钙代谢、骨密度的影响及临床观察

本实验以铁骨晶（多肽钙），进口脱脂奶粉，活性钙冲剂，贝壳钙为钙源添加于大鼠正常饲料中。观察结果表明：上述４组钙的吸收率分别为６４．４％，６９．１％，５９．９％，５１．６％；钙的储留率分别为８９．８％，９３．３％，８５．２％，７９．０％；钙的存留率分别为４３．６％，４９．０％，３２．４％，２６．８％；股骨指数分别为７．０２×１０（－３），６．４３×１０（－３），６．８４×１０（－３）。６．８８×１０（－３）；折断力（牛顿）分别为６０．５４±１２．５５，４６．８１±９．３２，４３．２６±１６．６２，３８．２４±１０．７９。同时以铁骨晶为钙源对７０例（５～６岁）儿童进行了血清Ｃａ，Ｆｅ，Ｚｎ，Ｈｂ及生长发育的检测。铁骨晶组的身高，体重，胸围分别比对照组增加。铁骨晶组血清Ｃａ，Ｆｅ，Ｚｎ，Ｈｂ也均有较好的改善。这表明铁骨晶具有较好的促进钙吸收利用作用，同时能增加骨强度作用。     

Urodilatin: a new peptide with beneficial effects in the postoperative therapy of cardiac transplant recipients

Summary Renal failure after heart transplantation (HTx) still remains a serious problem, especially when cyclosporin A is used for immunosuppression in the early postoperative therapy. To preserve good renal function without reducing immunosuppressive cyclosporin A treatment, we administered urodilatin (CDD/ANP-95-126) in a long-term, low-dose infusion in addition to the usual medication after heart transplantation. From November 1990 to June 1991, 51 patients (46 male and 5 female; mean age 48 years) were treated with a 620 ng/kg bw·min infusion for 96 h after HTx. The renal function and hemodynamic parameters of these urodilatin-treated patients were compared in this sequential study with 40 patients (33 male and 7 female; mean age 49 years) who had undergone HTx previously from May to November, 1990, as controls. In this phase IIa study, both groups did not differ significantly with respect to age, sex, indication for HTx, and preoperative renal function. In comparison with controls patients treated with urodilatin had a significantly better renal function: a reduction in the peak plasma creatinine (PC values day 4 : 1.5 ± 0.11 vs. 2.19 ± 0.19 mg/dl; P = 0.002), a lower peak serum urea (SU values day 4 : 109 ± 8 vs. 154.7 ± 8.94 mg/dl ; P = 0.0036), and a lower incidence of hemodialysis (6% vs. 10%) were observed. Adequate diuresis was maintained in spite of the reduction of furosemide by more than 60% (P = 0.005) on each day of urodilatin infusion in comparison with controls. The mean central venous pressure was significantly lower by about 50% (P = 0.02) during the administration of urodilatin in spite of reduced vasodilator medication with nitroglycerin. From this phase IIa study, we may conclude that urodilatin could be an important drug in intensive care treatment. For patients undergoing HTx, this peptide seems to be indicated for the improvement of renal function and cardiovascular status, especially in postoperative therapy using high-dose cyclosporin A treatment.Abbreviations ACE angiotensin converting enzyme - ANP atrial natriuretic polypeptide - ATG antithymocyte globulin - bpm beats per minute - bw body weight - CDD cardiodilatin - CDD/ANP-99-126 circulating form of vasorelaxant cardiac peptide - CHD coronary heart disease - CyA cyclosporin A - DCM dilated cardiomyopathy - GLM general linear model - hANP human atrial natriuretic polypeptide - HTx heart transplantation - NTG nitroglycerine - PC plasma creatinine - SU serum urea - SAS statistical analysing system     

Active transport of polypeptides in rabbit nasal mucosa: Possible role in the sampling of potential antigens

Transepithelial pathways of macromolecule transport have been studied in vitro in rabbit nasal respiratory mucosa, maintained at 27° C. Transepithelial electrical potential difference, short-circuit current and resistance were 3.4±0.5mV (submucosa positive), 65.0±6.7 A cm^–2 and 52.1±5.6 cm^–2 respectively (n=15). These electrical characteristics are those of a leaky epithelium allowing macromolecules to permeate paracellularly. A detailed permeation study of a polypeptide (elcatonin, M _w=3362) was also undertaken. Elcatonin mucosa-submucosa (J _ms) and submucosa-mucosa (J _sm) fluxes were measured by radioimmunoassay. With 10 g/ml elcatonin, J _ms was significantly larger than J _sm for the whole 120-min period of observation; net flux showed a maximum in the first 30 min (J _ms=13.6±1.0 ng cm^–2 h^–1, J _sm=1.4±0.1 ng cm^–2 h^–1, n=10). J _ms fell towards the value of J _sm if the temperature was reduced to 4°C or if the mucosa was simultaneously treated with 0.1 mM dinitrophenol and 3 mM monoiodoacetate. J _ms and J _net followed saturation kinetics with increasing elcatonin concentrations. Adrenocorticotropic hormone (M _r=4500) produced a similar pattern to elcatonin. However, J _ms and J _sm were not significantly different from each other at any time either for [³H]sucrose (M _w=342) or for [¹⁴C]polyethyleneglycol-4000 (M _w=4000) when present in the bathing medium at 500 M concentration. The results show active transport of polypeptides in parallel with passive permeation (possibly through leaky intercellular junctions). Active transport does not appear to be related to nonspecific pinocytosis but to receptor-mediated endocytosis. The latter may be important for the sampling of potential antigens from the nasal lumen.     

多肽:N-乙酰氨基半乳糖转移酶2的原核表达、纯化及酶活检测

目的：以人类多肽：N-乙酰氨基半乳糖转移酶2（ppGalNAc-12）为研究对象，利用载体pGEX-5X-3在大肠杆菌（E．Coli）BL21中原核表达其编码序列，并对表达产物进行纯化、复性及酶活检测。方法：首先利用PCR技术从克隆载体pDONR201-T2得到ppGalNAc-T2全长编码序列，将其亚克隆至原核表达载体pGEX-5X-3，形成重组表达质粒pGEX-5X-3／T2。重组质粒转化大肠杆菌DH5α，测序鉴定后转化BL21，异丙基硫代半乳糖（IPTG）诱导后，表达产物为主要以包涵体形式存在的融合蛋白。对其复性后用谷胱甘肽-琼脂糖（Glutathione-Sepharose）4B亲和层析柱进行纯化。然后根据ppGalNAc-T2的催化功能，设计底物，建立酶促反应体系，利用高效液相色谱（HPLC）进行酶活分析。结果：成功构建了原核表达重组载体pGEX-5X-3／T2，通过蛋白质电泳检测到分子量约为90 kD的融合蛋白的表达，利用亲和层析得到纯化的酶蛋白，并经Western印迹得以验证。反应后体系上柱洗脱后出现酶促反应的产物洗脱峰。结论：成功构建了重组表达载体pGEX-5X-3／T2，ppGalNAc-T2伞长编码序列被成功表达、纯化及复性，检测到具有酶活性。     

扇贝多肽对UVB辐射小鼠胸腺淋巴细胞的保护作用

目的：研究扇贝多肽(polypeptide ftom Chlamys，farreri)对中波紫外线(UVB)辐射损伤小鼠胸腺淋巴细胞的保护作用。方法：UVB辐射小鼠胸腺淋巴细胞，MTT法检测胸腺淋巴细胞的活性；酶生化法检测细胞谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性；流式细胞术检测细胞内活性氧(ROS)的产生量以及细胞凋亡率。结果：PCF能明显减轻UVB辐射对小鼠胸腺淋巴细胞的损伤；提高细胞GSH-Px、SOD和CAT活性；降低细胞中ROS的产生量和细胞凋亡率。结论：PCF对小鼠胸腺淋巴细胞具有明显的辐射保护作用。     

复方天麻蜜环糖肽片联用甲磺酸倍他司汀片治疗颈性眩晕

目的：观察复方天麻蜜环糖肽片联用甲磺酸倍他司汀片治疗颈性眩晕的疗效。方法：将94例以眩晕为主要症状的颈椎病患者,随机分为两组。治疗组47例,用复方天麻蜜环糖肽片联用甲磺酸倍他司汀片;对照组47例,单纯用甲磺酸倍他司汀片治疗,疗程为14d。结果：治疗组总有效率93.6%,显效率70.2%;对照组总有效率87.2%,显效率51.1%。治疗组治疗后血脂和血流变学明显改善。结论：复方天麻蜜环糖肽片联用甲磺酸倍他司汀片治疗颈性眩晕的疗效高于单用甲磺酸倍他司汀片。     

蛋白质及多肽类药物长效化研究进展

随着分子生物学技术和基因重组技术的发展,蛋白质与多肽类药物凭借其独特的优势已逐渐成为一种重要的临床药物类型;但稳定性差,半衰期短的缺点也极大限制了其在临床上的广泛应用。本文针对目前延长蛋白质和多肽类药物半衰期的具体方法及其注意事项进行了综述。     

强骨胶囊联合鹿瓜多肽注射液治疗老年原发性骨质疏松症的临床研究

目的探讨强骨胶囊联合鹿瓜多肽注射液治疗老年原发性骨质疏松症的临床疗效。方法选取2016年3月—2017年3月湖北医药学院附属人民医院(十堰市人民医院)收治的老年原发性骨质疏松症患者102例,根据用药的差别分成对照组和治疗组,每组各51例。对照组静脉滴注鹿瓜多肽注射液,10 mL与5%葡萄糖溶液250 mL配伍,1次/d。治疗组在对照组基础上口服强骨胶囊,1粒/次,3次/d。两组患者均治疗4周后进行疗效评价。观察两组的临床疗效,比较两组治疗前后VAS评分、ODI评分、骨密度(BMD)和血清学相关指标的变化情况。结果治疗后,对照组和治疗组总有效率分别为80.39%、96.08%,两组比较差异具有统计学意义(P0.05)。两组治疗后血清转化生长因子-β1(TGF-β1)、Ⅰ型原胶原N-端前肽(PINP)、骨钙素(BGP)、骨碱性磷酸酶(ALP)均显著升高,抗酒石酸酸性磷酸酶(TRACP)水平显著降低,同组治疗前后差异有统计学意义(P0.05);治疗后,治疗组TGF-β1、PINP、BGP、ALP高于对照组,TRACP水平低于对照组,两组比较差异具有统计学意义(P0.05)。结论强骨胶囊联合鹿瓜多肽治疗老年原发性骨质疏松症具有较好的临床疗效,可有效改善患者疼痛,增加BMD及改善骨代谢指标,具有一定的临床推广应用价值。