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Role of microRNA in Mesenchymal Stem Cells Differentiation Into Osteoblasts

Role of microRNA in Mesenchymal Stem Cells Differentiation Into Osteoblasts
Role of microRNA in Mesenchymal Stem Cells Differentiation Into Osteoblasts

Razavi Int J Med. 2013 November; 1(1): 5-10. Published online 2013 November 20.

Review Article

Role of microRNA in Mesenchymal Stem Cells Differentiation Into Osteoblasts

Aamina Shah 1

, Aftab Ahmad

2,*

1Institute of Biochemistry and Biotechnology, University of the Punjab, Lahore, Pakistan

2School of Biological Sciences, University of the Punjab, Quaid iAzam Campus, Lahore, Pakistan

*Corresponding author : Aftab Ahmad, School of Biological Sciences, University of Punjab, Lahore, Pakistan. Postal Code: 54590. Tel: +92-3007402202, Fax: +92-4299230960, E-mail: aftabac@https://www.doczj.com/doc/3c17007890.html,.

Received: September 16, 2013; Revised: October 21, 2013; Accepted:

November 3, 2013

Implication for health policy/practice/research/medical education:

MiRNAs, based on the type and function, is claimed to playvarious roles in osteogenesis. Some of the miRNA behave as positive ones while others act as negative regulators during osteoblast differentiation. Understanding the mechanism of action of various miRNAs is beneficial in the perception of various bone diseases and thus development of their treatments. Treatments through miRNAs can prove beneficial due to its small size, easy synthesis, targeted and quick delivery. Further work is needed to be done to make miRNA treatments available to large number of people suffering from various bone diseases.

Copyright ? 2013, Razavi Hospital; Published by Kowsar Corp. This is an open-access article distributed under the terms of the Creative Commons Attribution Li-cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Expression of gene networks are essential in regulat-ing several cellular functions that are controlled by the coordinate act of transcription factors (TFs), RNA binding proteins and microRNAs (miRNAs) (1). RNA transcripts of genome acquires stem, loop and bulge structure, most of which behave as primary miRNA which is cut by Drosha to form pre-miRNA. Exportin-5 transfers pre-miRNA to cy-toplasm (2, 3) where Dicer cuts it to create double strand-ed RNA (dsRNA) which is 21 - 25 mer nucleotide long and behave as miRNA by forming the RNA induced silencing complex along with the Argonaute protein (4). To some extent, miRNAs can then hybridize to mRNAs and inhibit mRNA translation (5) and promote mRNA degradation (6, 7). miRNA s are short non-coding RNA s, which are made up of ~21-nucleotides that regulate transcript local-ization, polyadenylation, and translation. MiRNAs act as negative regulators of gene expression directly by bind-ing specific sequences within a target mRNA (8, 9).

In a complex functional network, miRNA acts in such a manner that the expression of one coding gene can be supervised by various miRNAs, with each miRNA possibly controlling hundreds of distinguished genes (10, 11). The role of miRNA is even evident in the regulation of numer-ous physiological functions like differentiation of stem

cells, neurogenesis, hematopoiesis, immune response, development of cardiac and skeletal muscles, stress, etc. (12-18).

Mesenchymal Stem Cells (MSCs) known as multi-potent stromal cells isolated from various adult tissue sources have the ability to renew themselves and differentiate into multiple cell lineages (19-21). Stem cells have distinct miRNA expression profiles that can affect the intrinsic properties of self-renewal and pluripotency of stem cell (22-24).

2. Remodeling of Bone

During bone remodeling, the balance between the number and activities of osteoblasts and osteoclasts is of great significance (Figure 1). Osteoclasts have the func-tion of bone resorption whereas osteoblasts synthesize new bones. When remodeling occurs, cytokines are re-leased, which aid in recruiting the osteoclasts on the sur-face of bones. Osteoclast forms a ruffled boarder which contributes to their attachment to the surface of bone. In the cavity between the osteoclasts and the bone osteo-clast’s proton pump creates an acidic environment by re-leasing ions in the micro environment; thus, it dissolves the mineralized component of the bone matrix. The ma-trix gets exposed and degraded by cathepsin K ( 25 ). The

DOI: 10.5812/rijm.14849

reversal phase of bone remodeling is when mononuclear cells transmit signal for adjustments in bone to recruit new osteoblasts. In the beginning, osteoblasts increase rapidly to release an extracellular matrix in which type I collagen is present. Along with osteoblast differentiation, the maturation and mineralization of matrix occurs. When the bone surface is restored, mature osteoblasts may undergo programmed cell death or divide to form bone surface lining cells or may even differentiate to os-teocytes, present in calcified matrix and are responsive to mechanical stresses (26). Osteoclasts are derived from the monocyte/ macrophage lineage (25), whereas osteo-blasts are derived from MSCs which can also differentiate into adipocytes, chondrocytes, or myocytes, depending on the activation or inhibition of specific signaling path-ways (27). These signaling molecules include bone mor-phogenetic proteins (BMPs), transforming growth factor (TGF)-β, WNT, Hedgehog, parathyroid hormone, insulin-like growth factor-1, fibroblast growth factors and Notch.

F igure 1. Bone remodeling. Haematopoietic Stem Cell-Derived Osteo-clasts and Mesenchymal Stem Cell (MSC)-Derived Osteoblasts Participate in Couple and Sequential Process of Bone Remodeling.

MSCs can be isolated from bone marrow, cord blood, pe-ripheral blood, fallopian tube, fetal liver and lung. MSCs derived from bone marrow have the potential to prolifer-ate and get differentiated into osteoblasts, chondrocytes, adipocytes, cartilage, tendons, muscle and skin. Differ-entiation of MSCs into osteoblasts is very significant for bone remodeling. The differential expression of miRNAs has a major influence on the maintenance of differentia-tion of osteoblasts (28-30).

3. Effect of miRNA on Various Aspects of Bone Biology

3.1. Role of miRNA in Angiogenesis

Angiogenesis is a mechanism whereby regenerates and repair bones. At the time of injury, newly-formed blood vessels brings oxygen, nutrients, inflammatory cells, cartilage and bone to regenerating callus. Inflamma-tory cells and stromal cells produce VEGF to maintain angiogenesis. Several miRNA plays a role in angiogenesis like MiR-126, which promotes pro-angiogenesis of VEGFs and FGF by suppressing an intracellular inhibitor of an-giogenic signaling known as Sprouty-related protein 1 (Spred-1) (31). In vivo developmental angiogenesis can be maintained by endothelial cell-restricted miR-126 (32). miR-210 is associated with angiogenesis in patients suf-fering from osteonecrosis (ON) of the femoral head (33).

3.2. Rloe of miRNA in Osteosarcoma

Osteosarcoma (OS) is a malignant bone tumor that develops during adolescence. miRNA plays a role in the down-regulation of Fas expression, in OS expression of miR-20a and miR-19 is relatively more in metastatic low-Fas-expressing LM7 cells than in the parental non meta-static high-Fas-expressing SA OS-2 cells (34). miR-125b is regulated by signal transducer and activator of tran-scription 3 (STAT3), which binds in vitro to the promot-er region of miR-125b thus acts as a transactivator (35). BMP2 targets MiR-34c which induces changes on Notch1, Notch2 and Jag1. miR-34 and notch signaling could be used in therapies in various bone cancers (36). Down-Regulation of miR-183 promotes migration and invasion of OS by Targeting ezrin (37).

3.3. Role of miRNAs in Arthritis

Arthritis is a musculoskeletal state in which various mi-croRNAs plays an important role. MiR-146a inhibits osteo-clastogenesis and when administrated, it prevents from the destruction of joint in mice suffering from collagen-induced arthritis (CIA) by down regulating the expres-sion of c-Jun (transcription factor), Receptor activator of nuclear factor kappa-B ligand (NF-A Tc1), PU.1 (tran-scription factor), and tartrate-resistant acid phosphatise (TRA P) (38). MiR-223 is up- regulated in rheumatoid ar-thritis (RA) and lentivirus-mediated silencing of miR-223 reduces the severity of arthritis in mice (39). miR-140 is reduced in osteoarthritic chondrocytes, its knockdown promotes arthritis in mice. microRNAs should be critical factors for cartilage development and homeostasis (40). miR-221/222 and miR-323-3p are linked to rheumatoid arthritis when predicted using the human TNF in trans-genic mouse model (41). Dysregulation of 17 miRNAs con-tribute to RA pathogenesis (42).

3.4. Role of miRNA in Osteoporosis

In Osteoporosis, bone strenght is severely affected due to which patients have higher risk of fractures. Neuro-nal and microRNA-dependent pathways are used for the treatment of osteoporosis (43). Various positive and negative regulator miRNA of bone remodeling can be used for therapeutic purposes of osteoporosis like miR-29 family (44), miR-138 (45), etc. miR-133a in circulating monocytes is a potential biomarker for postmenopausal osteoporosis (46). MiR-34c regulates Notch1, Notch2, and Jag1 in osteoblasts to control the differentiation of osteo-clasts, presumably through cell/cell contact (35). miR-214 is elevated in patients with fractures due to low bone for-

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mation rate. The inhibitory role of miR-214 in bone for-mation has been revealed in transgenic mice. Both the activity of osteoblast as well as mineralization of matrix promoted by antagomir-214 and deceased by agomir-214, and miR-214 inhibits osteoblast differentiation by affect-ing ATF4. Therefore, if miR-214 is inhibited in osteoblasts, this strategy can be used for treatment against osteopo-

rosis (47).

miR-126Increase of angiogenesis (32)4. miRNAs as Regulators of Osteoblast Differentiation

4.1. miRNAs as Negative Regulators

Several miRNA s regulates bone remodeling by acting as negative regulators of osteoblast differentiation. miR-206 connexin 43 (Cx43) is one of the gap junction protein found in osteoblasts and its negatively regulated if miR-206 is overexpressed (30). miR-378 inhibits osteoblast dif-ferentiation by reducing the expression of nephronectin (NN, an extracellular matrix protein) (48). Osteoblast dif-ferentiation is also inhibited by miR-138 that targets FAK (Focal Adhesion Kinase) translation, consequently reduc-ing phosphorylation of FAK. Its target ERK1/2 proteins re-sults in decreased phosphorylation of Runx2 and Osterix expression 45.

4.2. Effect of miRN A on Runx2 in N egative Osteo-genesis

Runx2 is a bone specific transcription factor that regu-lates several genes and is required for the expression of several osteoblast differentiation genes such as type I collagen, osteocalcin (49). Runx2 gene expression is in-hibited by miR-204 and miR-211, which behaves as nega-tive regulators for the differentiation of osteoblasts and mineralization in mesenchymal progenitor cells and bone marrow stromal cell (BMSCs) (50). Various other

miRNA s like miR-23a, miR-30c, miR-34c, miR-133a, miR-135a, miR-137, miR-204, miR-205, miR-217, and miR-338 also target and decrease the expression of Runx2 lead-ing to the inhibition of osteoblast differentiation (51, 52). miR-355 also targets Runx2 mRNA and when miR-335 is overexpressed in hMSCs, it inhibits proliferation, migra-tion as well as osteogenic and adipogenic potential (53). MSCs differentiation into osteoblasts can be inhibited by miRNA s such as hsa-miR-31, hsa-miR-106a, hsa-miR-148a, and hsa-miR-424 and their target genes are Runx2, Cbfb and BMPs. miR-133 and miR- 135 inhibit the differentia-tion of osteoprogenitors by acting on Runx2 and Smad5 pathways (54). miR-26a also inhibits osteoblast differen-tiation by targeting Smad1 in human adipose tissue de-rived stem cells (55). Smad proteins are intracellular sig-naling components for TGF-β/ BMP signaling and BMP-2 via Smads activates osteoblast essential genes (56). TRPS1 is a chondrogenic GA TA transcription factor controlled by miRNA s (51, 52, 54). Due to mutation in Runx2 gene, dominantly inherited skeletal malformation cleidocra-nial dysplasia (CCD) occur. Mutations in the human Trps1 gene causesTricho-Rhino-Phalangeal syndrome types I and III (57-59). Ten Runx2-targeting miRNAs blocks MC3T3 osteoblast differentiation (52). Seven of these also targets TRPS1 and miR-30c is such a TRPS1/RUNX2-targeting miR-NA. TRPS1 inhibits the transcriptional activity of RUNX2 along with Runx2 promoter (58). The genetic interactions and biological correlations between RUNX2 and TRPS1 are remarkable, since they have common miRNA s that regulate their expression, which block their osteochon-drogenic functions, the activities of RUNX2 and TRPS1 leading to a common function linked to early stages of differentiation in skeletal cells (60).

Treatment of osteoblastic or chondrocytic cells with a representative TRPS1/RUNX2-targeting miRNA (miR-30c) results in opposite and coordinate effects on the expres-sion of a number of genes encoding components of sig-naling pathways (e.g. responding to TGF-β/BMP2, IGF1 or FGF2) that control bone or cartilage development (61-63). miR-30 also up-regulates TGF-β signaling components while osteoblast differentiation and the resulting sensiti-zation of TGF-β/SMAD3 signaling synergize with miR-30c to repress RUNX2 and the expression of osteoblast spe-cific ECM proteins (60).

PTK2 encodes FAK protein, which is the activator of ERK1 and ERK2 during osteoblast differentiation of hMSCs, miR-138 binds to 3′UTR of PTK2 and acts as negative regu-lator of hMSCs by maintaining its undifferentiated state (64, 65). The overexpression of miR-138 diminishes FA K at the protein level, whereas the inhibition of miR-138 by antimiR-138 causes the depression of FAK, which is regu-lated by miR-138 during osteoblast differentiation (66).

4.3. miRNA as Positive Regulators

Certain miRNAs act as positive regulators of osteogenic

differentiation like miR-29b down-regulates inhibitors of osteoblast differentiation such as HDAC4, TGF3, ACVR2A, CTNNBIP1, and DUSP2; thus, it promotes osteogenesis (67, 68). Increased levels of let-7, miR-24, miR-125b, and miR-138 repress the expression of non osteogenic target mRNAs involved in PDGF pathway, so these miRNAs up-regulates osteogenic differentiation (69). miR-218 acts as positive regulators during the differentiation of os-teoblasts to the final stage of forming mineralized tis-sue by inhibiting ERB1 (TOB1) and sclerostin (SOST) (70). When the same miRNA polycistron causes transcription of miR-3960 and miR-2861, they act on Runx2/miR-3960/ miR-2861 regulation feedback mechanism and help in os-teoblast differentiation (71). miR-26a/b and miR-29b both behave as positive regulators of osteogenic differentia-tion in unique stem cell type (USSC) by acting on CDK6 and HDAC4 which are osteoinhibitory proteins (72). 4.4. Effect of miRNA on Runx2 in Positive Osteogen-esis

During positive osteogenesis, RUNX2 is influenced by miRNAs like the expression of miR-20a increasing during the osteogenic differentiation and it stimulates the osteo-genesis of hMSCs. BMPs and Runx2 are important factors in the osteogenesis of MSCs (8, 73). miR-20a suppresses PPARγ, which is a very important factor for the differen-tiation of osteoblasts and also is essential for maintain-ing homeostasis of bones (74, 75). PPARγ is the antagonist of BMP and RUNX2 especially when the activated inhibits RUNX2 transcription (76) and down regulates the expres-sion of BMP (77). Due to lowered action of BMP and RUNX2 (77), the phenotypic expression of osteoblast is repressed by PPARγ. Antagonists of the BMP signaling pathway are generally categorized at three levels: extracellular (Nog-gin, Gremlin, Chordin), cell surface (Bambi and Crim1) and intracellular inhibitory (Smads 6 and 7) (78) .Bind-ing sites miR20a are also present in 3'-UTR of Bambi and Crim1. Bambi is negatively activated on by miR-20a and more BMP molecules bind to their receptors, thus, the RUNX2 expression is increased, whereas the role of Crim1 on BMPs after binding them is to reduce their secretion as mature active proteins and processing of pre-protein to mature BMP; hence, it causes the binding of pre-proteins to cell surface (73, 79) and suppression of Crim1 occuring after the transfection of miR-20a. therefore, there is an increase of free, mature and active BMP that activate BMP signaling, thus enhancing the osteogenesis of MSCs (73).

4.5. OstemiR and MSCs Differentiation Into Bone

OstemiR includes miR-30 family, let-7 family, miR-21, miR-16, miR-155, miR-322 and Snord85, whose expression alters during osteogenic differentiation. They play a role in stem-ness, epinegetics, and cell cycle-related mRNAs (80). Different miRNA have different roles in osteogenesis. Some of the miRNA behave as positive regulators; while others act as negative regulators during osteoblast dif-ferentiation. Understanding the role of various miRNAs is beneficial in understanding the various bone diseases and thus the development of their treatments. Treat-ments through miRNAs can be beneficial, due to its small size, easy synthesis, targeted and quick delivery. Further work needed to be done to make miRNA treatment avail-able to large number of people suffering from various bone diseases. Acknowledgements

There are no any specific acknowledgements. Authors’ Contribution

The Manuscript was prepared by A amina Shah under the supervision of Aftab Ahmad.

Financial Disclosure

There is not any financial disclosure for this study. Funding Support

There was no funding/support for present study. References

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较为明确的上消化道症状,如上腹不适、进食后饱胀,随着病情进展上腹疼痛加重,食欲下降、乏力。根据肿瘤的部位不同,也有其特殊表现。贲门胃底癌可有胸骨后疼痛和进行性吞咽困难;幽门附近的胃癌有幽门梗阻表现。 胃癌如何预防少吃或不吃腌菜。腌菜中含有大量的亚硝酸盐和二级胺,在胃内适宜酸度或细菌的作用下,能合成亚硝胺类化合物,这类化合物是很强的致癌物质。所以食品要新鲜,提倡冰箱冷藏。 不吃或少吃烟熏和油煎食物。熏鱼和熏肉中含有大量的致癌物质,如3-4苯并芘和环芳烃。油炸、烘烤、烧焦食物和重复使用的高温食油中也含有此类致癌物质,应尽量少食用。 不吸烟、少饮酒。吸烟与胃癌也有一定的关系,烟雾中含有苯并芘、多环芳香烃、二苯并卡唑等多种致癌或促癌物质,是食管癌和胃癌的病因之一。酒精本身虽不是致癌物质,但烈性酒会刺激胃粘膜,损伤粘膜组织,促进致癌物质的吸收,如果饮酒同时吸烟,其危害性更大。因为酒精可增强细胞膜的通透性,从而加强对烟雾中致癌物质的吸收。 要养成良好的饮食习惯。若饮食不定时定量、暴饮暴食、进食过快过烫,对胃是一个损伤性的刺激,与胃癌的发生有一定的关系。同时,食盐摄入量大,进餐时好生闷气与胃癌也有关系。

酶联免疫法检测试剂注册技术审查指导原则

附件1 酶联免疫法检测试剂注册技术审查指导原则 一、前言 本指导原则主要针对酶联免疫类检测试剂的主要原材料、生产工艺及反应体系、产品质量控制等环节提出指导性技术要求。 本指导原则系对酶联免疫法检测试剂的一般要求,申请人应依据产品特性确定其中的具体内容是否适用,若不适用,需详细阐述其理由及相应的科学依据。 本指导原则是对申请人和审查人员的指导性文件,但不包括注册审批所涉及的行政事项,亦不作为法规强制执行,如果有能够满足相关法规要求的其他方法,也可以采用,但是需要提供详细的研究资料和验证资料。应在遵循相关法规的前提下使用本指导原则。 本指导原则是在现行法规和标准体系以及当前认知水平下制订的,随着法规和标准的不断完善、科学技术的不断发展,其相关内容也将进行适时的调整。 二、适用范围 本指导原则适用于有关病原微生物检测的第三类体外诊断试剂的注册技术审查。其他酶联免疫法检测试剂(如作为二类管理的体外诊断试剂)可参考本指导原则执行。 三、基本要求 (一)基本原则 1.研制、生产用的各种原料、辅料等应制定其相应的质量标准,并应符合有关法规的要求。

2.试剂生产企业应具备相应的专业技术人员、仪器设备以及适宜的生产环境,获得《医疗器械生产许可证》;同时,应按照《体外诊断试剂生产实施细则(试行)》的要求建立相应的质量管理体系,形成文件和记录,加以实施并保持有效运行;还应通过《体外诊断试剂生产企业质量管理体系考核评定标准(试行)》的考核。企业应对试剂的使用范围做出明确规定,并经国家药品监督管理部门批准。 3.诊断试剂的研制应当按照科学、规范的原则,各反应条件的选择和确定应符合基本的科学原理。 4.试剂在研制、生产过程中所用的各种材料及工艺,应充分考虑可能涉及的安全性方面的事宜。 5.生产和质量控制的总体目标:保证试剂使用安全、质量稳定、工艺可控、检测有效。 (二)原材料质量控制 1.主要生物原料 与产品质量最密切相关的生物原料主要包括各种天然抗原、重组抗原、单克隆抗体、多克隆抗体以及多肽类、激素类等生物原科。这类原料可用于包被酶标反应板、标记相关酶(如辣根过氧化物酶、碱性磷酸酶等)、中和反应用抗原或抗体、制备校准品(标准品)等。使用前应按照工艺要求对这类生物原料进行质量检验,以保证其达到规定的质量标准。主要生物原料若为企业自己生产,其工艺必须相对稳定;若购买,其供应商要求相对固定,不能随意变更供应商,如果主要原料(包括工艺)或其供应商有变更,应依据国家相关法规的要求进行变更申请。 主要生物原料的常规检验项目一般包括: (1)外观 肉眼观察,大部分生物原料为澄清均一的液体,不含异物、浑浊或摇不散的沉淀或颗粒;或者为白色粉末,不含其他颜色的杂质;特殊生

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第十三章口腔颌面部肿瘤重点 口腔颌面部是肿瘤的好发部位之一,可以发生各种类型的肿瘤。本节仅就口腔颌面部常见的肿瘤作简单的介绍。口腔内的囊肿呈非真性肿瘤,为了便于叙述,也包括在本节之内。 一、良性肿瘤 口腔颌面部可发生各种良性肿瘤。发生于软组织者,如涎腺混合瘤、牙龈瘤、血管瘤、淋巴管瘤、神经纤维瘤、纤维瘤等。发生于骨组织者,如巨细胞瘤、骨瘤等。口腔颌面部还有些良性肿瘤与成牙组织有关,属牙源性的肿瘤,如牙瘤、造釉细胞瘤等。现将几种常见的肿瘤分别叙述如下。 (一)混合瘤(多形性腺瘤)(Mixed Tumor,Pleomorphic adenoma)涎腺混合瘤为口腔颌面部最常见的肿瘤之一。来源于涎腺上皮。肿瘤内除上皮成份外,还常有粘液、软骨样组织等。涎腺混合瘤好发于腮腺(图1),其次为腭部及颌下腺。下面以腮腺混合瘤为例叙述其临床表现及治疗原则。 图1 腮腺混合瘤(左腮部) 【临床表现】 腮腺混合瘤多见于中年。一般无明显自觉症状,生长缓慢,病程可达数年甚至数十年之久。肿瘤多表现为耳下区的韧实肿块,表面呈结节状,边界清楚,中等硬度,与周围组织不粘连,有移动性,无压痛。如肿瘤出现下述情况之一时,应考虑有恶变之可能。①肿瘤突然增长迅速加快,②移动性减少甚至固定,③出现疼痛或同侧面瘫等。 【治疗原则】 腮腺混合瘤的治疗以手术彻底切除为原则。术前一般不宜作活检。肿瘤的包膜常不完整,有时瘤细胞可侵入包膜或包膜外组织,若切除不彻底则将复发。故手术时不宜采用剜除肿瘤的方法而应将肿瘤连同其周围的腮腺组织一并切除。术中要注意保持面神经。如有恶性变,应按恶性肿瘤的治疗原则处理。 (二)成釉细胞瘤(Ameloblastoma) 成釉细胞瘤是一种常见的、来自牙源性上皮的颌骨中心性肿瘤。瘤细胞的形态与牙胚中的成釉细胞相似,故称为成釉细胞瘤。

胃癌与癌前病变的关系分析

胃癌与癌前病变的关系分析 为研究肠上皮化生(IM)及不典型增生(ATP)与胃癌的关系,作者分析证实了近10年的病理活检资料,现将研究结果报告如下: 1 材料和方法 本组材料为我院1983年~1993年常规病理活检资料完整、内镜采取的胃粘膜组织及外科手术中胃大部切除标本368例。观察取材部位主要是胃窦部大弯、小弯,胃体部大弯、小弯以及窦部的前壁、后壁,胃体部前壁、后壁等。每例取材1~8块,以体积分数为10福尔马林液固定。石蜡包埋切片,HE常规染色。 2 结果 IM51.9%(189/368),ATP20.2%(79/386)。IM在胃溃疡发病率为55.9%,在胃癌为58.5%,两种疾病之间无统计学差异(P>0.05),在高分化腺癌和低分化腺癌的发病率分别为67.6%和50.9%,经统计学处理,两者之间差异不显著(P>0.05)。ATP在胃溃疡病中发生率为17.6%,在胃癌中37.8%,两者的发生率有显著差别(P<0.01),在高分化胃腺癌和低分化胃腺癌的发生率分别为53%和24.5%,两者之间的差异显著(P<0.01)。在非癌非溃疡的其它胃部疾病的胃粘膜中,IM占29.6%,ATP占12.2%,其中胃炎中占10.5%,IM,ATP的发生率均明显低于胃溃疡病及胃癌。IM,ATP等胃的良性病变中,男女之比约为5:1。并随年龄增加而检出率亦增高,其发病的高峰年龄组为40岁~59岁,与胃癌发病年龄一致。IM,ATP病变部位的分布,以窦小弯所占比例较大,胃体部病变检出率较低且程度轻。可见,胃的良性病变以胃窦部的检出率最高,病变的程度也最重,尤其是胃窦小弯部,与癌的病变部位分布一致。 3 讨论 近几年来认为,幽门螺杆菌(简称Hp)的感染是慢性萎缩性胃炎、胃溃疡病及胃癌发生的重要致病因素之一。自1983年Warren和Marshall在胃炎病人胃窦粘膜活检标本中发现并培养出幽门螺杆菌后,引起了国内外学者的重视。人体感染了Hp后,在遭到外界不利因素作用或内环境紊乱时,胃粘膜组织发生了病变。原来桔红色泽丧失,代以灰色灰绿色,粘膜水肿或厚薄不均,缺乏完整性光滑性,出现粘膜表面粗糙或凹凸不平。透镜电镜下发现,慢性萎缩性胃炎病人胃粘膜活检标本的病理变化,粘膜上皮及腺上皮细胞普遍低矮,细胞间隙增宽,排列不整,腺腔扩大,腺管萎缩,分泌颗粒减少,间质水肿伴有淋巴细胞、粒细胞等炎症细胞浸润,少数间质出血等变化。有时局限性组织再生过程占优势,则可发生息肉,病变严重时,胃粘膜形态与小肠相似(肠化)。所以,病理诊断的根据,以胃固有膜腺体萎缩为主,伴有IM,炎细胞浸润,淋巴滤泡形成,粘膜内纤维组织增生或腺体异型增生等。

饮酒与胃癌关系的病例对照研究

饮酒与胃癌关系的病例对照研究方案设计 一、研究背景: 1973-1975年以及1990-1992年的调查显示,胃癌死亡率均居各种死亡率之首,我国也是胃癌高发区。2000年,胃癌已成为我国三大肿瘤相关死因,平均死亡率达48.6/10万,男性和女性胃癌分别居肿瘤相关死因第3位和第2位。[1]381目前其病因尚未阐明,早期常无特异症状而易被忽略。 二、研究目的 通过调查研究对象生活习惯,探讨饮酒与胃癌之间的关系 三、研究方法 1.研究对象: 病例组: 2011年3月~2011年9月, 选择在某市某几家指定医院年龄在18岁以上属于本市常住人口的确诊为原发性胃癌患者。若有下列情况之一则排除:①此次检查不是首次确诊为胃癌②具有其它相关疾病(如肝肠疾病)可能引发胃病为并发病的患者③有胃癌遗传史的患者。 诊断标准:按照中华人民共和国卫生部的胃癌诊断标准(WS316-2010),采用纤维胃镜检查或上消化道造影检查。 对照组: 在患者居住周边有相同生活习惯的居民中,按1∶1配对,随机选取与病例同民族、同性别、同居住地、年龄差别±5岁,无消化系统疾病、无肿瘤病人员为对照组。 2.影响因素 (1)生活习惯影响生活习惯(尤其饮食习惯)很大程度上影响个体身体健康状况;(2)生活环境影响不同环境的空气质量和成分不尽相同;可能导致患者经常吸入的物质及其含量存在一定的差异; (3)工作环境影响不同职业对象处于不同的工作环境,日常接触物质有所不同,吸入物有所不同;此外,不同职业可能存在不同的压力状况,饮食和作息规律也会有所不同;(4)个体间在体质、健康状况、遗传、疾病史等方面存在的差异会对研究结果产生一定影

ELISA检测方法

ELISA(酶联免疫吸附测定,enzyme linked immunosorbent assay)指将可溶性的抗原或抗体结合到聚苯乙烯等固相载体上,利用抗原抗体结合专一性进行免疫反应的定性和定量检测方法。 基本原理: ①使抗原或抗体结合到某种固相载体表面,并保持其免疫活性。 ②使抗原或抗体与某种酶连接成酶标抗原或抗体,这种酶标抗原或抗体既保留其免疫活性,又保留酶的活性。 ③在测定时,把受检标本(测定其中的抗体或抗原)和酶标抗原或抗体按不同的步骤与固相载体表面的抗原或抗体起反应。用洗涤的方法使固相载体上形成的抗原抗体复合物与其他物质分开,最后结合在固相载体上的酶量与标本中受检物质的量成一定的比例。 ④加入酶反应的底物后,底物被酶催化变为有色产物,产物的量与标本中受检物质的量直接相关,故可根据颜色反应的深浅有无定性或定量分析。由于酶的催化效率很高,故可极大地放大反应效果,从而使测定方法达到很高的敏感度。 双抗夹心法 夹心法常用于检测大分子抗原,一般的操作步骤为: ①将具有专一性的抗体固著于塑胶孔盘上,完成后洗去多余抗体; ②加入待测检体,检体中若含有待测的抗原,则其会与塑胶孔盘上的抗体进行专一性键结; ③洗去多余待测检体,加入另一种对抗原专一的一次抗体,与待测抗原进行键结; ④洗去多余未键结一次抗体,加入带有酶的二次抗体,与一次抗体键结; ⑤洗去多余未键结二次抗体,加入酶底物使酵素呈色,以肉眼或仪器读取呈色结果。 间接法 间接法常用于检测抗体,一般的操作步骤为: ①将已知的抗原固著于塑胶孔盘上,完成后洗去多余的抗原。

②加入待测检体,检体中若含有待测的一次抗体,则其会与塑胶孔盘上的抗原进行专一性键结。 ③洗去多余待测检体,加入带有酶的二次抗体,与待测的一次抗体键结。 ④洗去多余未键结二次抗体,加入酶底物使酶呈色,藉仪器(ELISA reader)测定塑胶盘中的吸光值(OD值),以评估有色终产物的含量即可测量待测抗体的含量。 竞争法 竞争法是一种较少用到的ELISA检测机制,一般用于检测小分子抗原,其操作步骤为: ①将具有专一性的抗体固著于塑胶孔盘上,完成后洗去多余抗体; ②加入待测检体,使检体中的待测抗原与塑胶孔盘上的抗体进行专一性键结; ③加入带有酶的抗原,此抗原也可与塑胶孔盘上的抗体进行专一性键结,由于塑胶孔盘上固著的抗体数量有限,因此当检体中抗原的量越多,则带有酶的抗原可键结的固著抗体就越少,亦即,两种抗原皆竞相与塑胶孔盘上抗体键结,即所谓竞争法之由来。 ④洗去检体与带有酶的抗原,加入酶底物使酶呈色,当检体中抗原量越多,代表塑胶孔盘内留下之带有酶的抗原越少,显色也就越浅。 注:当需要侦测无法获得两种以上单一性抗体的抗原,或是不易得到足够的纯化抗体以固著于孔盘上时,一般会考虑使用竞争法ELISA。

酶联免疫吸附测定法

酶联免疫吸附测定法(ELISA) 1.定义 (3) 2.原理 (3) 2.1抗原抗体反应 (3) 2.2免疫测定在临床检验中的应用 (5) 3.ELISA的类型 (5) 3.1双抗体夹心法测抗原: (6) 3.2双抗原夹心法测抗体 (6) 3.3间接法测抗体 (6) 3.4竞争法测抗体 (7) 3.5竞争性测抗原 (7) 3.6捕获包被法测抗体 (7) 3.7ABS-ELISA法 (8) 4.ELISA试剂的组成 (9) 4.1固相载体: (9) 4.2包被的方式 (9) 4.3包被用抗原:天然抗原、重组抗原、合成多肽抗原。 (10) 4.4包被的条件: (10) 4.5洗涤液: (10) 4.7酶的催化性; (11) 4.8结合物的制备 (11) 4.9结合物的保存 (12) 4.10酶的底物 (12) 4.11酶反应终止液 (12) 4.12参考标准品 (13) 4.13加样: (13) 4.14保温 (13)

4.15保温方式: (13) 4.16室温温育的反应 (13) 4.17洗涤 (14) 4.18显色 (14) 4.19比色 (14) 4.20酶标比色仪 (15) 4.21结果判定 (15) 4.22定量测定 (16) 4.23ELISA的操作要点 (16)

1.定义 酶联免疫吸附测定法(Enzyme Linked ImmunoSorbent Assay),简称ELISA,采用抗原与抗体的特异反应将待测物与酶连接,然后通过酶与底物产生颜色反应,对受检物质进行定性或定量分析的一种检测方法。 2.原理 采用抗原与抗体的特异反应将待测物与酶连接,然后通过酶与底物产生颜色反应,可对受检物质的定性或定量分析。 2.1抗原抗体反应 2.1.1可逆性 抗原与抗体结合形成抗原抗体复合物的过程是一种动态平衡,其反应式为: Ag+Ab→Ag·Ab 抗体的亲和力(affinity),可以用平衡常数K表示:K=[Ag·Ab]/[Ag][Ab],Ag·Ab的解离程度与K值有关。高亲和力抗体的抗原结合点与抗原的决定簇在空间构型上非常适合,两者结合牢固,不易解离。解离后的抗原和抗体均能保持原有的结构和活性。 2.1.2特异性 抗原抗体的结合发生在抗原的决定簇与抗体的结合位点之间。化学结构和空间构型互补关系,具有高度的特异性。因此,在很多时候,测定某一特定的物质不需分离待测物。2.1.3最适比例 只有当抗原抗体的浓度比例是当时,才出现可见反应。 以沉淀反应为例(Ab量固定,Ag量递增)

胃癌与饮食的关系论述

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