表皮生长因子微球的制备与评价

目的制备表皮生长因子（EGF）微球并对其生物学活性进行评价。方法利用改进的复乳法．以聚乳酸,羟基乙酸共聚物（PLGA）作为载体,制备EGF微球。检测EGF微球形貌表征、微球粒径分布、载药率、包封率和释药行为。用噻唑蓝（MTr）法测定增殖度,研究不同浓度EGF微球对细胞增殖能力的影响,研究相同浓度不同剂型EGF对细胞增殖的影响．研究微球载体的安全性。结果EGF微球粒径约为200nm,粒径分布比较均一,微球之间无粘连,分散性好。载药率为0．02％．包封率为85％。释药符合释放动力学模型,释放长达24h。不同浓度EGF微球均促进细胞增殖。其中10μg／L为最适质量浓度（与对照组EE,P〈0．01）。质量浓度10μg/L时,EGF微球组与EGF原液组相比差异有统计学意义（P〈0．01）。不同质量浓度空微球对细胞没有毒性,不影响细胞增殖（组间没有差异,P〉0．05）。结论成功制备EGF微球。细胞实验证明EGF微球制备过程中EGF保持原有活性。与EGF原液比较．EGF微球促进细胞增殖能力更强,微球载体对细胞没有毒性作用。     

制备复合生长因子的缓释微球并考察其对细胞的影响

目的:制备复合碱性成纤维细胞生长因子的可降解缓释微球,考察其生物活性保存情况,以及其对上皮细胞的作用.方法:采用改良的乳化冷凝法交联制备明胶缓释微球,将其加入上皮细胞的培养液中,用细胞计数法、四甲基偶氮唑盐微量反应比色法(MTT法)测定细胞增殖情况.结果:缓释微球平均粒径(12.36±3.56)μm;培养1 d后各组细胞计数、吸光度(A)值差异均无显著性意义;5 d后,缓释微球组细胞计数、吸光度(A)值明显高于对照组;7 d后,缓释微球组值仍高于其它组,但差异无显著性意义.结论:复合生长因子的缓释微球制备工艺简便,成球性好;能较长时间持续释放活性生长因子,明显促进细胞增殖.     

明胶微球乙肝疫苗动物免疫效果研究

目的 研究并优化微球乙型肝炎疫苗的配方,观察微球乙肝疫苗对温度的稳定性。方法 用明胶包裹ＨＢｓ制备微球,设计不同配方及不同粒径微球乙肝疫苗、冻干微球乙肝疫苗于不同温度放置一定时间,免疫动物观察免疫效果。结果 微球疫苗ＨＢｓ包裹率〉９０％,微球疫苗的免疫效果受佐剂配方及制备程序等因素影响,〈１０μｍ的微球（５．６μｍ）免疫效果明显优于〉１０μｍ的微球（２５．４μｍ）（Ｐ〈０．０２）及铝佐剂组（Ｐ〈０     

功能高分子微球研究：99MTC明胶微球的制备及其动物活体显像

以聚合物溶液为分散介质、戊二醛为交联剂可制备出具有高反应活性的明胶微球(GM)。通过改变聚合物溶液浓度、调节反应搅拌速度可控制微球粒径。当聚合物溶液浓度为25％、搅拌速度为250rpm时,可得到10～50um粒径范围的明胶微球。用此法制备的明胶微球表面光滑、亲水性好、贮存期长、~(99m)Tc标记率高,经静脉注射后,能定向进入肺部。初步实验表明,明胶微球可望作为肺灌注显像剂;成为质优、价廉、使用方便的肺部疾患诊断用新材料。     

用多孔明胶微球作为示踪剂载体

用天然胶原蛋白加交联剂制备多孔明腔微球，直径３０－６０μｍ，含微孔。将其作为荧光金载体用于垂体前叶神经纤维原的研究获得较理想的结果，并有以下优点：１．吸收示踪剂硬结后可按需要捣成直径６０μｍ以上坚硬颗粒，使用方便，２．供示踪会着的表面积大，运载示踪剂量多；３．示踪剂从微球中缓慢释放；４．明胶化学性质稳定，不影响示踪剂活性或神经组织吸收摄取示踪剂的能力。     

乳脂肪球表皮生长因子8与乳腺癌相关性研究进展

乳脂肪球表皮生长因子Ⅷ(MFG-E8)是一种亲脂性糖蛋白,作为分泌型多效蛋白广泛存在于多种组织和细胞中,参与细胞间及细胞与基质间的相互作用.大量研究表明MFG-E8通过促进肿瘤细胞的增殖、抑制凋亡、促进肿瘤血管生成等在乳腺癌的发生、侵袭和转移过程及预后中起重要作用.     

乳脂肪球表皮生长因子Ⅷ在冠心病中的作用

乳脂肪球表皮生长因子Ⅷ(MFG-E8)广泛存在于人体各种组织中,参与细胞间及细胞与基质间的相互作用。大量研究显示,MFG-E8在冠心病(CHD)中有重要作用,可作为CHD诊断标志物,也具有防治CHD的潜在功效。     

bFGF缓释微球的制备及其促雪旺细胞分裂增殖的初步研究

研究碱性成纤维细胞生长因子(bFGF)缓释微球的制备方法及其对雪旺细胞的促分裂增殖作用。以聚乳酸-羟基乙酸共聚物(PLGA)为载体材料,采用复乳包囊法制备bFGF-PLGA缓释微球,并对微球的形态学、粒径分布、载药量和包封率、及体外释药进行研究。将bFGF、bFGF-PLGA微球分别加入不同组的雪旺细胞培养液中,分别测定雪旺细胞的数量、活力和细胞周期。结果显示,复乳包囊法制备的bFGF-PLGA缓释微球表面光滑圆整,球体均匀度好;微球平均粒径为1.552±0.015μm,平均径距为1.310±0.010;载药量和包封率分别为(27.18×10-3)%±(0.51×10-3)%、66.43%±1.24%;微球的体外释药过程较为稳定,11d释药率为72.47%。体外细胞试验中,培养1、2d时,bFGF组的细胞计数、吸光度明显高于bFGF缓释微球组;培养3、4d时,bFGF组和bFGF缓释微球组的细胞计数、吸光度无统计学差异;培养6、8d时,bFGF缓释微球组的细胞计数、吸光度明显高于bFGF组。流式细胞仪检测结果显示,培养2d后,bFGF组的G2/M S期百分数高于bFGF缓释微球组;培养4、8d后,bFGF缓释微球组的G2/M S期百分数高于bFGF组,差异具有统计学意义。说明采用复乳包囊法制备bFGF-PLGA缓释微球的工艺可行,微球中bFGF的生物活性保存良好,能缓慢持续释放活性bFGF,促进雪旺细胞的分裂增殖。     

接种缓释霍乱微球疫苗的试验研究

把霍乱弧菌Ｉｎａｂａ５６９Ｂ株的外膜蛋白（ＯＭＰ）包入可生物降解的聚乳酸－聚乙二醇共聚体内，制备成缓释微球疫苗。对微球在动物体内的靶向分布研究，表明口服微球后主要分布在肝、脾和肠系膜淋巴结等部位。采用微球疫苗免疫ＢＡＬＢ／ｃ小鼠后，收集其唾液、血清和粪便，采用ＢＡ－ＥＬＩＳＡ法检测了ｓＩｇＡ和ＩｇＧ抗体滴度。在第６周，口服微球疫苗组的小鼠粪便ｓＩｇＡ滴度比口服游离ＯＭＰ对照组高５倍；在第１２周时ｓＩｇＡ高达１０倍（２２４／２２），同时小鼠血清ＩｇＧ滴度也比对照组高１４倍（１９２０／１４０）。采用霍乱弧菌经腹腔攻击免疫小鼠后，发现口服微球疫苗组保护率为５０％～７０％，皮下注射微球疫苗组保护率为８０％～１００％，而口服游离ＯＭＰ组保护率仅为１０％。     

平阳霉素明胶微球的制备及其释药特性

采用优化的双相乳化冷凝聚合法，制备粒径适当的平阳霉素明胶微球，研究其体内外和颈动脉栓塞化疗的释药特性；并对介入栓塞给药、静脉给药、灌注给药3种方法的效果加以对比分析。结果表明明胶微球粒径分布较好，体外释药有明显的缓释作用，微球颈动脉栓塞可以显著提高肿瘤化疗效果。     

Controlled release systems for proteins based on gelatin microspheres

The preparation and characterization of biodegradable gelatin microspheres for the controlled release of peptides and proteins has been investigated. Bovine serum albumin (BSA) was chosen for incorporation into the gelatin microspheres and the spheres were characterized for the in vitro release of BSA and other properties. BSA was labelled with fluorescein isothiocyanate (FITC) for easy analysis. FITC-BSA was entrapped into the gelatin microspheres using a polymer dispersion technique developed in our earlier studies. The morphological characteristics of microspheres were analysed by optical and scanning electron microscopy (SEM). The optical and SEM photographs of FITC-BSA microspheres showed the solid spherical nature of the spheres. The entrapment efficiency of FITC-BSA was about 62%. The in vitro release pattern of FITC-BSA showed that 51 % of the entrapped drug was released during the first day and the release followed approximate zero order kinetics from day 2 onwards. The total release of FITC-BSA lasted for about 8 days. SDS-PAGE analysis revealed that BSA was not degraded by this preparation of microspheres.     

Transforming growth factor alpha and epidermal growth factor in human pancreatic cancer.

Overexpression of the epidermal growth factor receptor (EGFR) has been reported as an important molecular abnormality in human pancreatic cancer. There is in vitro evidence that simultaneous overproduction of one of its ligands, transforming growth factor alpha (TGF-alpha), might result in an autocrine loop with an increased proliferation signal. We analysed by immunocytochemical staining a retrospective series of human pancreatic cancers, chronic pancreatitis, and normal fetal and adult pancreatic tissues for the presence of TGF-alpha and epidermal growth factor (EGF). Ductal epithelial cells showed TGF-alpha immunoreactivity in both normal tissue and chronic pancreatitis, and 95 per cent of tumours showed strong immunoreactivity. In contrast, EGF immunoreactivity was not found in normal pancreas, but was expressed in 12 per cent of pancreatic carcinomas. Well-defined areas of EGF immunoreactivity in exocrine ducts showing reactive changes in pancreatitis might represent a benign response to tissue damage similar to that previously described in the gastric mucosa.     

Immunohistochemical investigation of epidermal growth factor receptor expression in ameloblastomas

Immunohistochemical analysis was performed to determine the localization of epidermal growth factor receptor (EGFR) in ameloblastomas. Ameloblastoma samples were classified into follicular, plexiform, and basal cell types. The number of cases in each category was 17, 19 and 3, respectively. Ameloblastomas, disregarding their histological type, consist of two cell forms: peripheral columnar cells and central stellate cells. The frequency of EGFR expression was much higher in the latter than in the former (P<0.005). On analysis with respect to histological types, the frequency of EGFR expression in columnar cells was not significantly different between the follicular and the plexiform types, but was observed more frequently in the stellate cells in the follicular than in the plexiform ameloblastomas (P<0.05). This pattern of EGFR expression was not consistent with the PCNA staining pattern, but was similar to that of keratin expression which we have reported previously. The present study suggests that EGFR expression in ameloblastomas is closely associated with tumour differentiation, and squamous differentiation in particular.     

表皮生长因子受体与胃癌的研究进展

胃癌的发生与发展机制十分复杂,涉及多种细胞病理改变。表皮生长因子受体(epidermal growth factor receptor,EGFR)及其参与的信号转导通路在胃癌的发生发展中起着重要的作用。近年来,发现多数肿瘤对放化疗存在的耐药性,因此在肿瘤的基因水平寻找诊断指标以及靶向治疗,已经成为近年来研究热点之一。本文综述表皮生长因子与胃癌的研究进展。     

Gene expression and immunolocalization of heparin-binding epidermal growth factor-like growth factor and human epidermal growth factor receptors in human corpus luteum

BACKGROUND: The objective of this study was to elucidate gene expression and immunolocalization of heparin-binding epidermal growth factor-like growth factor (HB-EGF) and human epidermal growth factor receptor (HER) family in the human ovary during luteal growth and regression. METHODS: Ovaries obtained from pre-menopausal women were used for immunohistochemistry and semiquantitative RT-PCR analysis. RESULTS: Immunoreactive HB-EGF was not detected in follicles or oocyte, while HB-EGF became apparent in granulosa luteal cells in the early luteal phase, and most abundant in the mid-luteal phase, but less abundant in the late luteal phase. Immunostaining for HER1 was very weak in granulosa luteal cells in the early and mid-luteal phases, and was not detected in the late luteal phase. Immunoreactive HER4 was abundant in the early luteal phase and became less abundant in the mid-luteal phase, whereas it was negative in the late luteal phase. Semiquantitative RT-PCR analysis revealed that HB-EGF and HER1 mRNA levels were high in the mid-luteal phase, whereas HER4 mRNA expression was high in the early luteal phase. CONCLUSIONS: HB-EGF may play a vital role in regulating luteal growth in a juxtacrine manner and through activating HER4 signalling.     

重组人表皮生长因子及碱性成纤维细胞生长因子联合应用促进内镜鼻窦手术后术腔创面上皮化的疗效观察

目的观察rhEGF凝胶及bFGF滴眼液联合应用对鼻内窥镜鼻窦相关手术后的术腔创面黏膜上皮化的效果。方法对30例（60侧）经鼻内镜全鼻窦开放术患者进行同体对照观察，左侧为观察组，鼻窦术后每周在鼻内镜下作一次详尽术腔清理，于术腔置放rhEGF凝胶及bFGF滴眼液，混合抗生素和地塞米松的明胶海绵；右侧为对照组鼻窦每天使用鼻腔冲洗器自行冲洗鼻腔，鼻内使用局部类固醇激素，每周作鼻内镜下的术腔清理1次。连续内镜随访12周，观察双侧术腔上皮化过程。结果观察组治愈（28例）93．33％，好转（2例）6．67％，平均上皮化时间4周；对照组治愈（24例）80％，好转（6例）20％，平均上皮化时间9周，平均上皮化时间差异有统计学意义（P〈0．01）。结论鼻内窥镜鼻窦手术后联合应用rhEGF及bFGF可以促进术腔上皮化，显著缩短上皮化时间，治疗效果好。     

Dependence of activation of the epidermal growth factor receptor on its affinity and oligomerization

R. E. Kavetskii Institute for Problems in Oncology and Radiobiology, Academy of Sciences of the Ukrainian SSR, Kiev. (Presented by Academician of the Academy of Medical Sciences of the USSR A. S. Efimov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 113, No. 1, pp. 84–87, January, 1992.     

The efficacy of doxorubicin microspheres for hepatic micrometastases in a rat tumour model

The use of sustained-release microspheres is of potential benefit as an adjuvant treatment for patients with occult hepatic micrometastases. This study investigates the response of a model of implantable adenocarcinoma micrometastases in the livers of DA rats following the intraportal injection of doxorubicin-incorporated ion-exchange microspheres compared to free drug bolus administration. A point-counting technique was used to determine the percentage of liver consisting of tumour 13 days after treatment. This was used as an indicator of tumour response, as was the derived tumour mass. There was a significantly higher tumour response in animals treated with the microspheres compared to animals treated with free drug delivered at the same concentration. This effect, however, was shown to decrease with a delay in the time of treatment. The tumour response of the sustained-release microspheres was achieved in the absence of any detectable local or systemic toxicity. This study demonstrates the potential of sustained-release microspheres in the treatment of patients with hepatic micrometastases.     

Disappearance of epidermal growth factor receptor is essential in the fusion of the nasal epithelium

Epidermal growth factor (EGF) and receptor (-R) signaling pathway is required for epithelial cell growth and differentiation such as the degeneration of the medial edge epithelial cells during the fusion process of secondary palate formation. As epithelial fusion takes place during primary palate formation, we investigated the involvement of the EGF-R in fusion of the medial (MNP) and lateral (LNP) nasal prominences of the mouse embryo was examined. Immunoreactivity of EGF-R was investigated in embryonic day 10 embryos (32–37 somite stages). The EGF-R immunoreactivity was observed in the nasal epithelia of the presumptive fusion area before fusion. It became undetectable just prior to the fusion and faintly reappeared at the time of the fusion. In contrast, the non-fusing epithelial cells of the nasal groove maintained the immunoreactivity throughout these stages. In order to elucidate whether the EGF/EGF-R signaling pathway was involved in nasal epithelial fusion, EGF solution was injected into the exocoelum of explanted mouse embryos, and the embryos were cultured for 18–24 h by whole embryo culture (WEC). This exogenous EGF inhibited fusion of nasal pro-minences in 66.7–81.5% of the embryos. Treatment with EGF for 4–14 h showed that exogenous EGF dis-turbed the EGF-R disappearance and normal alteration of epithelial cell morphology in the fusion area. These results suggest that temporal disappearance of the EGF/EGF-R signaling from presumptive fusion of the nasal prominences is required for morphological change of the epithelial cells leading to the fusion of MNP and LNP.