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1.
许旺细胞源神经营养因子受体在外周神经组织中的分布研究 总被引:9,自引:6,他引:3
目的探讨许旺细胞源神经营养因子(SDNF)受体在外周神经的分布状况.方法应用放射性受体结合法检测外周神经组织中125I-SDNF的特异性结合.结果外周神经组织中存在许旺细胞源神经营养因子的特异性结合位点,且该特异性结合位点具有如下特点(1)高亲和力,Kd为(93.11±0.52)pmol/L;(2)低结合容量,Bmax为(8.91±0.26)fmol/mg;(3)可饱和性,饱和曲线呈双曲线型,Scatchard分析的回归线呈直线;(4)可逆性,结合常数K1为(3.91±0.63)×107M-1×min,解离常数K-1为(3.38±0.54)×10-3min-1;(5)特异性.结论外周神经组织中存在许旺细胞源神经营养因子的高亲和力受体,故为许旺细胞源神经营养因子发挥神经营养作用的靶组织. 相似文献
2.
目的探讨人p53四聚功能域在提高抗前列腺特异抗原(PSA)/抗人CD3双特异性单链抗体(scFv)亲和力方面的作用。方法利用递归聚合酶链反应(PCR)法扩增人IgG3上游铰链区与人p53四聚功能域融合基因,克隆入pUC19载体中构建pUC19/IgG3/p53克隆载体。将抗 PSA/CD3双特异性scFv克隆入pUC19/IgG3/p53载体中,构建多价抗PSA/CD3双特异性scFv融合基因。将融合基因克隆入真核表达载体pSeeTag2-B中,转染HeLa细胞进行表达,表达产物纯化后利用流式细胞仪进行活性测定。结果获得了多价抗PSA/CD3双特异性scFv融合基因,基因全长1638 bp,可编码546个氨基酸,与已发表的抗PSA/CD3双特异性scFv和人p53四聚功能域基因cDNA序列一致。表达产物经SDS-PAGE和Western印迹实验证实为约67×103的特异蛋白条带,纯化后经流式细胞仪检测可以特异性地结合PC-3细胞和人外周血单个核细胞(PBMC),亲和力高于双特异性scFv。结论人IgG3上游铰链区/p53四聚功能域基因与抗PSA/CD3双特异性 scFv基因融合后表达产物的功能性亲和力大大提高,为提高抗体的功能性亲和力开辟了新的思路。 相似文献
3.
用电镜放射自显影技术对人射出精子17β-雌二醇结合位点进行定位研究,结果表明此位点位于精子细胞膜上,分布在顶体区、赤道区、顶体后区、尾部中段等不同部位。用放射配体受体法对正常生育男性射出精子雌激素结合位点进行定量测定,其最佳实验条件为:(1)精子与氚标雌二醇在0℃~4℃保温18~20小时,细胞与激素才能达到充分的结合。(2)精子悬液浓度为80-130×10_6/ml时,细胞与加入的~3H-E_2比例适当,可有良好的结合。(3)精子活动率低时能与~3H-E_2发生特异性结合的精子少,本实验所测的精子活动率在40%以上。实验结果表明人精子雌激索结合位点的含量为0.75±0.38×10~(-3)pmole/10~7精子,但此位点尚不能认为是雌激素受体。 相似文献
4.
P物质对人增生性瘢痕组织块中组胺释放的影响 总被引:1,自引:0,他引:1
目的观察P物质(SP)对人增生性瘢痕(HS)组胺释放的影响及两者相互作用的条件。方法人HS和正常皮肤(NS)的标本分别取自笔者单位行整形术的8例烧伤患者,切下后立即用等渗盐水清洗,并修剪成0.5~1.0 mm~3的组织块。利用荧光分光光度计测定在不同浓度SP、不同SP作用时间、不同浓度Ca~(2+)的作用条件下,组织块中肥大细胞(MC)脱颗粒释放组胺的情况,并计算释放率。结果当SP浓度达到1×10~(-6)mol/L时,HS即有明显的组胺释放,释放率为(50.0±3.6)%,明显高于0 mol/L SP[(44.0±3.2)%,P<0.01],并呈剂量依赖性。5×10~(-5)mol/L SP作用15 min内,HS已有约90%的组胺释放,并呈时间依赖性。当Ca~(2+)浓度为5×10~(-3)mol/L时,HS组胺释放率最高,基本呈剂量依赖性,但在Ca~(2+)浓度为1×10~(-3)mol/L时,释放率却出现一过性下降。在上述3个条件下,HS中SP对MC脱颗粒释放组胺的作用均明显强于NS(P<0.01)。结论人HS中SP对MC的作用明显强于人NS,可能与瘢痕的增生和瘙痒有密切的关联。 相似文献
5.
许旺细胞源神经营养因子受体在脊髓组织中的分布研究 总被引:6,自引:2,他引:4
目的 探讨脊髓组织中是否存在许旺细胞源神经营养因子 (SDNF)受体及其在亚细胞水平的分布情况。 方法 应用放射性配体结合法检测脊髓中1 2 5 I- SDNF的特异性结合。 结果 (1)脊髓组织 1 2 5 I- SDNF特异结合的最大容量 (Bmax)为 (2 .86± 0 .2 2 ) fmol/ mg蛋白 ;平衡解离常数 (Kd)为(4 9.4± 6 .5 ) pmol/ L;(2 )动力学分析显示 K1 为 (9,2± 0 .7)× 10 7M- 1 × min- 1 ,K- 1 为 (4 .2± 0 .5 )× 10 - 3min- 1 ;(3)特异性分析表明对 SDNF高度特异性 ;(4 )亚细胞分布 :特异结合位点以微粒体膜含量最高。 结论 脊髓中存在 SDNF的受体 ,表明脊髓为 SDNF的靶组织 相似文献
6.
在结肠直肠癌大致治愈性切除后,约有70%病例出现复发,已知在其进展中部分病人发生急性相蛋白反应,其中C后应蛋白(CRP)增高者常伴有肿瘤复发.作者观察36例结肠直肠癌施行治愈性切除术后急性相蛋白反应与肿瘤复发的关系,按CRP值将36例病人分为两组:(1)有急性相蛋白反应者(CRP>5mg/L)15例;(2)无急性相蛋白反应者,21例,均至少随访24个月.结果 术后2~7个月初步复查,按有无急性相蛋白反应分为两组,其病人年龄、肿瘤Dukes分期和肿瘤部位相仿,有可比性,但有急性相反应组中男性病人较多(11:4),两组多数病人的癌胚抗原(CEA)值在正常范围内,低于60U/L.随访24个月后,有急性相反应组的肿瘤复发率明显较高(P<0.01),直肠癌病人术后急性相反应阳性者偏多(P=0.16),但其术后局部复发率与结肠癌相仿(2/7:2/8),复发多见于术后18月内.两组病人的血白蛋白浓度、淋巴细胞计数和血小板计数均无明显差异,但在存有急性相反应组中,病人的血白细胞数增高(7.4×10~6/mL:5.4×l0~6/mL),嗜中性白细胞比例也高(4.8×10~6/mL:3.l×10~6/mL). 相似文献
7.
目的观察IVF-ET技术对早期胎盘滋养层细胞MAPK信号通路基因表达的影响,探讨IVF-ET技术对早期胎盘发育和功能的影响。方法 IVF-ET周期中双胚胎移植后妊娠7~8周,经超声引导下减胎获得的胎盘绒毛组织作为研究组(IVF-ET组,28例),自然妊娠双胎7~8周人工流产中获得的胎盘绒毛组织作为对照组(8例)。利用Affymetrix HG-U133Plus 2.0基因芯片对两组胎盘绒毛组织进行芯片杂交分析。用定量反转录聚合酶链反应(qRT-PCR)在两组胎盘绒毛组织中验证其中的8个差异表达基因,从基因芯片数据中选取差异表达基因进行无监督聚类分析和基因本体(GO)功能生物信息学分析。结果与对照组相比,IVF-ET早期胎盘MAPK信号通路有32个差异表达基因(差异倍数≥2倍),13个基因上调,19个基因下调。上调基因是PLA2G12B、JUN、RPS6 KA3、ACVR1B、FGF18、PRKACB、RASGRP3、PLA2G4A、FGFR4、PDGFRA、CACNB2、RPS6 KA2和SOS1,下调基因是STK4、GNG12、MAPK9、DUSP16、IL1R2、MAP3 K8、BRAF、STK3、HSPA2、HSPB1、DUSP4、EGFR、IL1R1、TGFB1、RASA1、RPS6 KA5、GADD45G、PLA2G2A和DUSP5。经qRT-PCR检测,与对照组相比,IVF-ET组8个MAPK信号通路基因成员中JUN、PLA2G4A、PDGFRA和SOS1上调,MAPK9、EGFR、TGFB1和GADD45G下调,与基因芯片检测结果一致。MAPK信号通路基因定位显示,IVF-ET组胎盘绒毛组织中受到影响的基因主要位于MAPK信号通路的上游。结论 IVF-ET来源的早期胎盘MAPK信号通路基因表达与自然妊娠早期胎盘中存在差异,差异的基因涉及MAPK信号通路的多种关键功能,进而可能影响IVF-ET胎盘早期发育和功能。 相似文献
8.
为增强肿瘤浸润淋巴细胞的趋肝性和杀伤靶细胞能力 ,我们将肿瘤浸润淋巴细胞 (TIL)与半乳糖基抗CD3单抗结合 ,制备了半乳糖基抗CD3单抗 TIL(McAb TIL) ,并从形态学上证明McAb TIL在体外有良好的趋肝细胞性和杀伤自体肝癌细胞能力〔1,2〕,本研究进一步从定量检测杀伤活性角度探讨McAb TIL杀伤自体肝癌细胞的能力。1.材料与方法 :( 1)效应细胞的制备 :①TIL制备 :见参考文献〔1〕的方法。②McAb TIL制备 :取培养 3周、生长良好之H2 2 小鼠肝癌TIL 2 0× 10 6 /ml共 4ml,与半乳糖基抗CD3… 相似文献
9.
猪到人异种移植超急性排斥反应的靶抗原 总被引:1,自引:0,他引:1
目的 探索猪到人异种移植超急性排斥反应的靶抗原。方法 对近年来国内、外有关文献进行检索 ,并作综述。结果 α半乳糖基 (α Gal)是目前公认的猪到人异种移植超急性排斥反应的主要抗原 ,其表达受α 1,3半乳糖转移酶 (α 1,3GT)控制。克服α Gal引起的超急性排斥反应的方法有免疫吸附天然抗体、酶消化α Gal、α GT基因敲除及转基因技术等。除α Gal外 ,还存在与人血清中天然抗体相结合的其它抗原 ,如红细胞表面相对分子质量为 40× 10 3 的分子 ,猪胚胎脑细胞上相对分子质量为 2 10× 10 3 、10 5× 10 3 及 5 0× 10 3 的抗原分子等。结论 α Gal是异种移植超急性排斥反应的主要靶抗原 ,除α Gal外还存在有待进一步研究的非α Gal。 相似文献
10.
傅鹏 《国际泌尿系统杂志》1992,(1)
实验性肾小球硬化有发生与高脂血症及脂质在肾小球的沉有关。一般情况下,肾小球肥大发生于肾小球硬化之前。为了解肾小球硬化过程中脂质有可能致病作用,作者把一侧肾切除的大鼠随机分为两组(每组16只)。分别以普通饲料料或普通饲料加4%胆固醇和1%胆酸饲料,共21周,研究其肾小球儿细胞成分及尿蛋白的排泄情况。结果表明,胆固醇饲养组肾小球横截面积(13.11±0.39×10~3μ~2)较对照组(11.13±0.44×10~3μ~2)显著增加(P<0.01),前者系膜枢(1.87±0.07×10~3μ~2)也较后者(1.50±0.08×10~3μ~2)显著扩大(P<002)。与上述病理改变密切相关的尿蛋白量(以控制饮食期间曲线下的平 相似文献
11.
N Fujimoto K Ozu H Inatomi T Okamura A Sugita 《Nihon Hinyōkika Gakkai zasshi. The japanese journal of urology》1991,82(6):984-989
Fibronectin (FN) is a high molecular weight glycoprotein widely distributed in the body and has a number of biological activities. Recently, there have been reports on the relationship between plasma fibronectin (pFN) levels and malignant diseases, but the significance of pFN is still unclear. Using immunoturbidimetric assay, we measured pFN levels of 24 healthy controls and 61 patients with urological malignant diseases, and obtained the following results. 1. pFN levels before treatment. 1) pFN level was 379 +/- 60.6 micrograms/ml and 356 +/- 123.7 micrograms/ml in the healthy controls and patients, respectively. There was no significant difference. 2) pFN level in patients with metastases was 320 +/- 92.9 micrograms/ml and had no statistical difference as compared with patients without metastases (371 +/- 132.7 micrograms/ml) and controls, despite the decrease in the mean value. 3) pFN level in patients with poor prognosis (300 +/- 107.8 micrograms/ml) was significantly lower than that in patients with good prognosis (410 +/- 157.2 micrograms/ml) and controls (p less than 0.05). 2. pFN levels during conservative treatments for advanced disease. pFN level in patients with a rapid progressive disease (287 +/- 64.4 micrograms/ml) was significantly lower than that in patients with a slow progressive disease (327 +/- 43.3 micrograms/ml) (p less than 0.01). These data suggest that low pFN level predicts rapid progression of the disease and poor prognosis in patients with a urological malignant disease. 相似文献
12.
《BONE》2014
Circulating plasma fibronectin (pFN), produced by hepatocytes, is a major component of the noncollagenous bone matrix where it was recently shown in vivo in mice to control the biomechanical quality as well as the mineral-to-matrix ratio in bone. FN fibrillogenesis is a process generally requiring FN binding to cellular integrins, and cellular tension to elongate and assemble the molecule. Whether soluble pFN undergoes cell-mediated assembly in bone is not fully established. FN is a well-known substrate for transglutaminases (TGs), which are protein-crosslinking enzymes capable of stabilizing macromolecular structures. The role of this modification regarding the function of FN in bone matrix has remained unknown. Osteoblasts express two TGs—transglutaminase 2 and Factor XIIIA—and we have shown that Factor XIIIA is the main TG active during osteoblast differentiation. In the present study, conducted using MC3T3-E1 osteoblast cultures and bone marrow stromal cells, we demonstrate that pFN requires a TG-mediated crosslinking step to form osteoblast matrix in vitro. This modification step is specific for pFN; cellular FN (EDA-FN) does not serve as a TG substrate. Inhibition of pFN assembly using a TG inhibitor, or depletion of pFN from cell culture serum, dramatically decreased total FN matrix assembly in the osteoblast cultures and affected both the quantity and quality of the type I collagen matrix, and decreased lysyl oxidase and alkaline phosphatase levels, resulting in decreased mineralization. Experiments with isozyme-specific substrate peptides showed that FXIIIA is responsible for the crosslinking of pFN. Addition of exogenous preactivated FXIIIA to osteoblast cultures promoted pFN assembly from the media into matrix. Exogenous TG2 had no effect. Analysis of pFN and EDA-FN fibrils by immunofluorescence microscopy demonstrated that they form distinct matrix network, albeit with minor overlap, suggesting different functions for the two FN forms. Further analysis using EDA-FN blocking antibody showed that it regulated preosteoblast proliferation whereas pFN depletion from the serum had no effect on this process. In conclusion, our study shows that pFN assembly into bone matrix in vitro requires FXIIIA transglutaminase activity making pFN assembly an active, osteoblast-mediated process. 相似文献
13.
Safety and efficacy of intramuscular human placenta‐derived mesenchymal stromal‐like cells (cenplacel [PDA‐002]) in patients who have a diabetic foot ulcer with peripheral arterial disease
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Stephanie C Wu Richard Pollak Robert G Frykberg Wei Zhou Maha Karnoub Vladimir Jankovic Steven A Fischkoff Denesh Chitkara 《International wound journal》2017,14(5):823-829
The objective of this study was to examine the safety of cenplacel (PDA‐002) in patients with peripheral arterial disease (PAD) and a diabetic foot ulcer (DFU). Cenplacel is a mesenchymal‐like cell population derived from full‐term human placenta. This phase 1, dose‐escalation study investigated cenplacel in diabetic patients with chronic DFUs (Wagner grade 1 or grade 2) and PAD [ankle‐brachial index (ABI) >0·5 and ≤0·9], enrolled sequentially into each of four dose cohorts (3 × 106, 10 × 106, 30 × 106 and 100 × 106 cells; administered intramuscularly on study days 1 and 8 in combination with standard of care). Overall, cenplacel was well tolerated in all 15 patients in the study. Before enrollment, nine patients had an ulcer for ≥6 months and 11 had an ABI of 0·7–0·85. No patient met dose‐limiting toxicity criteria and no treatment‐related serious adverse events were reported. There was preliminary evidence of ulcer healing in seven patients (five complete; two partial) within 3 months of cenplacel treatment, and circulating endothelial cell levels (a biomarker of vascular injury in PAD) were decreased within 1 month. Cenplacel was generally safe and well tolerated in patients with chronic DFUs and PAD. Outcomes from this study informed the doses, endpoints, biomarkers and patient population for an ongoing phase 2 trial. 相似文献
14.
van Vliet AI van Alderwegen IE Baelde HJ de Heer E Bruijn JA 《Kidney international》2002,61(2):481-489
BACKGROUND: Glomerulosclerosis is a severe complication of many immunologically-mediated kidney diseases, eventually resulting in loss of renal function. In chronic graft-versus-host disease (GvHD) in mice, a model for human lupus nephritis, the end-stage sclerotic lesions were previously shown to contain large amounts of fibronectin (FN). This study investigated a domain-specific accumulation process of circulating plasma FN (pFN) in sclerotic lesions. METHODS: GvHD mice were injected with FITC-conjugated pFN or pFN-fragments, with or without heparin pre-incubation. pFN fragments were generated by digestion of pFN by cathepsin D, after which the fragments were separated on a heparin affinity column. Thus, two batches of fragments were obtained with either low or high affinity for heparin. RESULTS: FN accumulation was accompanied by an up-regulated expression of integrin alpha5beta1, the FN receptor, in the periphery of sclerotic lesions. pFN-FITC injected into GvHD mice was trapped in sclerotic glomeruli within 24 hours. Both heparin and non-anti-coagulant heparin blocked the accumulation of pFN-FITC, indicating that the protective effect of heparin in the trapping of FN is independent of its anticoagulant properties, and probably results from preventing direct binding of FN in the sclerotic lesions. To investigate whether FN binds in the glomerulus via the heparin-binding regions, pFN fragments were generated and injected into GvHD mice. Whereas the fraction with high affinity for heparin did not accumulate in the sclerotic glomeruli, the fraction with low affinity for heparin did. Partial sequencing of the isolated peptides showed that in the glomerulus fibronectin does not bind via the heparin II binding region. CONCLUSIONS: We hypothesize that the protective effect of heparin treatment may be the result of steric hindrance of the specific binding sites, that is, the I1-5 and/or III1 self-assembly sites of FN. 相似文献
15.
《BONE》2015
Serotonin (5-HT) – a monoamine with a variety of physiological functions – has recently emerged as a major regulator of bone mass. 5-HT is synthesized in the brain and the gut, and gut-derived 5-HT contributes to circulating 5-HT levels and is a negative modulator of bone mass and quality. 5-HT's negative effects on the skeleton are considered to be mediated via its receptors and transporter in osteoblasts and osteoclasts; however, 5-HT can also incorporate covalently into proteins via a transglutaminase-mediated serotonylation reaction, which in turn can alter protein function. Plasma fibronectin (pFN) – a major component of the bone extracellular matrix that regulates bone matrix quality in vivo – is a major transglutaminase substrate in bone and in osteoblast cultures. We have recently demonstrated that pFN assembly into osteoblast culture matrix requires a Factor XIII-A (FXIII-A) transglutaminase-mediated crosslinking step that regulates both quantity and quality of type I collagen matrix in vitro. In this study, we show that 5-HT interferes with pFN assembly into the extracellular matrix in osteoblast cultures, which in turn has major consequences on matrix assembly and mineralization. 5-HT treatment of MC3T3-E1 osteoblast cultures dramatically decreased both pFN fibrillogenesis as analyzed by immunofluorescence microscopy and pFN levels in DOC-soluble and DOC-insoluble matrix fractions. This was accompanied by an increase in pFN levels in the culture media. Analysis of the media showed covalent incorporation of 5-HT into pFN. Minor co-localization of pFN with 5-HT was also seen in extracellular fibrils. 5-HT also showed co-localization with FXIII-A on the cell surface and inhibited its transamidation activity directly. 5-HT treatment of osteoblast cultures resulted in a discontinuous pFN matrix and impaired type I collagen deposition, decreased alkaline phosphatase and lysyl oxidase activity, and delayed mineralization of the cultures. Addition of excess exogenous pFN to cultures treated with 5-HT resulted in a significant rescue of pFN fibrillogenesis as well as type I collagen deposition and mineralization. In summary, our study presents a novel mechanism on how increased peripheral extracellular 5-HT levels might contribute to the weakening of bone by directly affecting the stabilization of extracellular matrix networks. 相似文献
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目的 通过观察特异性环氧酶2(COX-2)抑制剂塞来昔布(celecoxib,CXB)诱导人多囊肾囊肿衬里上皮细胞凋亡,初步探讨该药诱导细胞凋亡的作用机制。 方法 (1)原代培养囊肿衬里上皮细胞,分为对照组、CXB组,采用Brdu法检测细胞增殖状态。(2)应用透射电镜观察细胞超微结构。(3)TUNEL法检测细胞凋亡及凋亡率。(4)应用AnnexinV+流式细胞术检测CXB诱导细胞凋亡及凋亡率。(5)应用免疫印迹法检测Bcl-2、Bax蛋白的表达。 结果 (1)Brdu结果显示,CXB能抑制多囊肾囊肿衬里上皮细胞的增殖,在24~72 h,浓度为(0.25~2)×10-5 mol/L的范围内呈时间和剂量依赖性。(2)电镜下可见细胞核浓缩、染色质聚集、胞浆空泡化、凋亡小体出现、沟裂和裸核形成等典型凋亡征象。(3)TUNEL法显示,对照组细胞凋亡率为(2.8±0.2)%,2×10-5 mol/L CXB作用24、48 h细胞凋亡率为(28.5±1.6)%和(48.5±1.2)%,两者差异有统计学意义(P < 0.05)。(4) AnnexinV+流式细胞仪法结果显示,不同浓度(0.5、1、2×10-5 mol/L)CXB处理24 h凋亡率分别为(7.15±0.11)%、(7.76±0.08)%和(12.15±0.07)%,显著高于无血清对照组(3.15±0.05)%;不同浓度CXB处理48 h的凋亡率分别为(18.36±0.17)%、(24.87±0.25)%和(53.66±0.32)%,显著高于无血清对照组(13.53±0.21)%,组间差异均有统计学意义(P 均< 0.01)。(5)Western 印迹结果显示,随CXB作用时间延长,Bcl-2的表达逐渐减弱而Bax的表达逐渐增强,Bcl-2/Bax的比值逐渐减少。结论 塞来昔布呈时间和剂量依赖性抑制囊肿衬里上皮细胞增殖,通过下调Bcl-2,上调Bax,减少Bcl-2/Bax的比值诱导细胞凋亡。本研究结果为将CXB用于治疗常染色体显性多囊肾病提供了实验依据。 相似文献
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目的研究骨桥蛋白(osteopontin,OPN)在人正常月经周期子宫内膜的表达。方法采用免疫组织化学法对51例人正常月经周期子宫内膜OPN蛋白质进行定位和定量检测,Western blotting法测定增殖期及分泌期OPN蛋白水平,采用逆转录-聚合酶链反应(RT-PCR)方法检测18例人正常月经周期子宫内膜增殖期及分泌期OPN mRNA的表达。结果OPN蛋白质主要分布在正常子宫内膜腺上皮细胞,增殖早期、中期无表达,增殖晚期出现,分泌中期、晚期表达最强。月经期子宫内膜腺上皮细胞表达较强。OPN mRNA表达分泌期强于增殖期(P<0.05)。Western blotting检测结果显示正常子宫内膜组织中存在OPN蛋白,分泌期含量较高。结论OPN蛋白质及mRNA在正常子宫内膜中的表达呈现明显周期依赖性。分泌中、晚期表达增强提示其可能参与胚胎着床。 相似文献
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为了研究LHRH(促黄体激素释放激素)对雄性大鼠垂体细胞分泌LH(促黄体激素)是否有自身激发作用,我们用不同幅度(1×10~(-10)~1×10~(-8) mol/L)和不同频率(1~4脉冲/小时)的LHRH脉冲刺激灌流的SD雄性大鼠垂体前叶细胞,观察了在灌流系统中细胞LH的分泌反应。结果表明,在高幅度(1×10~(-9)mol/L或更大)和高频率(3脉冲或更高)LHRH脉冲作用下,灌流的垂体细胞可表现自身激发作用,即在LHRH刺激一定时间后,同样的LHRH刺激产生更大的LH释放。但是,低幅度(1×10~(10)mol/L)LHRH即使在高频率下也不能显著地改变LH反应性。上述实验说明:离体成年雄性大鼠垂体前叶细胞存在对LHRH的自身激发作用,这种自身激发作用的产生主要依赖于LHRH脉冲的幅度和频率。 相似文献
20.
Fibronectin mRNA and protein accumulation, distribution, and breakdown in rabbit anti-glomerular basement membrane disease 总被引:7,自引:0,他引:7
Fibronectin is a multifunctional matrix protein which by immunofluorescence appears to be present in increased amounts during glomerular injury. To examine fibronectin metabolism in glomerular injury, an anti-glomerular basement membrane model that progresses to severe glomerular crescent formation, glomerulosclerosis, and interstitial fibrosis was used. Fibronectin was purified from rabbit plasma, and a monoclonal antibody raised against rabbit fibronectin was used for immunolocalization and quantitation of fibronectin protein. RNA and protein were extracted from isolated glomeruli and whole renal cortex at various times during progression of disease. At day 4, there was a 2.5-fold increase in fibronectin protein which by immunofluorescence appeared to be in the glomerular mesangial area. There was no increase in glomerular fibronectin mRNA at this time. This discrepancy is consistent with the conclusion that, at this early time point, the increased glomerular fibronectin comes predominantly from plasma. By day 7, glomerular fibronectin mRNA and extractable fibronectin protein were increased in association with bright immunofluorescence along the inner aspect of Bowman's capsule where early crescents were forming. Similarly, at day 14, crescents stained very brightly for fibronectin. These results are consistent with the conclusion that, at later time points, fibronectin is synthesized in glomeruli in association with cell division and crescent formation. Degradation of fibronectin in glomerular and cortical extracts was demonstrated under normal and nephritic conditions by finding fibronectin proteolytic fragmentation by Western blot.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献