激光与生物组织相互作用：光子迁移与生物传热理论

激光热疗中,激光与生物组织相互作用研究主要包含两方面：光子在生物组织中的迁移规律,以及光生扫热在生物组织在的传导。对前者的描述主要为,基于传输理论的解析法和Ｍｏｎｔｅ￣Ｃａｒｌｏ模拟,生物组织中光子迁移规律的研究能定量描述组织中的光分布,并进一步获得生物组织中的热分布;考虑到了生物组织特性,所建立了生物组织中温度场分布及变化规律。光子迁移与生物传热理论是研究激光热序不可分割的传热模型,全面描述了生     

基于时域的时间分辨荧光光谱的蒙特卡洛模拟

利用蒙特卡洛方法构建了生物组织基于时域的时间分辨荧光光谱的仿真模型,并将应用该模型获得的模拟结果与生物组织的实验光谱进行了比较。结果表明：吸收系数与散射系数分别影响光谱的不同区域;低浓度情况下,模拟结果与实验光谱符合得较好（x^2〈1．2）;高浓度下,实验光谱强度会被浓度效应削弱,以致影响其与模拟光谱的吻合程度。该方法为研究生物组织荧光光谱提供了一种新思路。     

食管癌细胞诱导肥大细胞迁移的小鼠模型

目的建立小鼠肥大细胞（mast cell,MC）迁移模型,探讨化疗药物三氧化二砷对人食管癌EC109细胞株生长的杀伤机理。方法利用肥大细胞的特征性蛋白酶抗体及其免疫荧光标记MC和PI标记EC109细胞内DNA;以流式细胞术分析小鼠腹腔液中肥大细胞各亚型的百分率及肿瘤细胞周期变化;使用激光扫描共聚焦显微镜显示肥大细胞内分泌颗粒的分布。并通过组织化学方法,观察各种诱导处理后小鼠肠组织肥大细胞由肠道向腹腔移动的变化。结果①根据流式细胞仪点图分布分析,将小鼠肥大细胞分为：类胰蛋白酶阳性、类糜蛋白酶阴性（MC T）;类糜蛋白酶阳性、类胰蛋白酶阴性（MC C）和类胰蛋白酶阳性、类糜蛋白酶阳性（MC TC）三种亚型,且T型MC明显多余TC型和C型（P〈0.05）;以共聚焦显微镜显示三种亚型的MC均含有丰富的分泌颗粒并分布于细胞膜内侧,为其出芽突起形成储备的状态。②经组织切片观察到诱导处理后小鼠肠组织MC由肠道向腹腔移动,且胰酶对MC的诱导作用大于食管癌细胞和As2O3。③经诱导迁移入腹腔的MC可能与癌细胞周期由S期向G2/M期跨越相关;As2O3能延迟食管癌细胞的G0/G1期,阻碍细胞向S期跨越,从而抑制食管癌细胞的生长。结论食管癌细胞移入小鼠腹腔,主要诱导T型MC参与免疫反应。在生物机体内环境（这里指MC影响）的条件下,As2O3对肿瘤细胞生长的作用主要表现为促使癌细胞周期的G0/G1期向S期跨越延迟,或G2/M期进入细胞分裂的延迟。     

海洋软体动物组织中的铁生物矿化研究概况

海洋软本动物组织中存在铁的生物矿化,并且部分矿化组织含有生物磁铁矿（Ｆｅ３Ｏ４）就无脊椎动物组织中的铁生物矿化及Ｆｅ３Ｏ４形成机理的研究作一综合介绍。     

陆地生物地球化学模型的应用和发展

以TEM和DNDC模型为例,在分析国外生物地球化学模型发展基础上,按照模拟方法,应用目的,元素类型,生态系统类型和空间尺度等对现有的生物地球化学模型进行了分类,对生物地球化学模型的基本框架（植物,大气和土壤3个组分及植物－大气,植物－土壤和土壤－大气界面等3个界面）,以及内部基本过程（物理的,化学的和生物的过程）进行了总结分析,对目前生物地球化学模型建立中的几个问题（如跨尺度问题,地理信息系统（GIS）和遥感技术结合,考虑人类活动的影响和生物地球化学模型的比较研究）的研究动态进行了评价。     

早期自然流产患者绒毛中肥大细胞数量与CD34和TNF-α表达的相关性研究

国内外研究表明,肥大细胞（MC）在不同动物的发情周期以及胚泡着床、正常分娩和自然流产等过程中可能具有重要作用。本研究以不明原因早期自然流产患者的绒毛组织为研究对象,以正常妊娠（孕5～9周）人工流产患者的绒毛为对照,以4%中性甲醛为固定液,用阿辛蓝-萨红染色（ADS）法,结合细胞记数半定量,分析MC在绒毛中的分布特点和变化规律。     

黑鲷不同组织的9种同工酶谱

对黑鲷（Sparus macrocephalus）9种组织的9种同工酶采用垂直聚丙烯酰胺平板电泳技术进行研究。结果表明,乳酸脱氢酶（LDH）、醇脱氢酶（ADH）、苹果酸脱氢酶（MDH）、苹果酸酶（ME）、超氧化物歧化酶（SOD）、过氧化物酶（POD）、酯酶（EST）、半乳糖脱氢酶（GAD）、甲酸脱氢酶（FDH）等酶在表型、分布和活性上组织特异性明显。还对眼和肠组织同工酶表达特性的生理意义进行了讨论。     

组织的前向散射、后向漫射

人体组织的光学性质是光医学和组织光学领域中的最基本的研究课题之一。当激光与生物肌体相互作用后所产生的各种生物效应,这些即取决于所施加的激光参量,又决定于被作用组织的结构、物理和生物特性。从激光诊断或治疗的角度考虑,由于光或激光只有透过组织,才能到达组织的深部和内部器官。所以,首要解决的问题是组织对光的通透性及其机理的研究。光通过组织时,光强和光的偏振状态会发生变化。令He－Ne激光照射组织,分别在组织的透射方和反射方探测光强．当光垂直（θ＝0°）或以角度θ入射到具有一定厚度的组织时,探测器以α的角度测量前后向的光强分布．根据实验数据分别绘制了前向散射和后向漫射光强的极坐标曲线．当θ－0°、探测器的角度为α＝0°时光的强度最大（前向散射）．旋转探测器的角度（改变α）探测到的光强其图形为一个圆。当入射光的角度θ由0°变到60°时,光的强度降低了31．65％．此时旋转探测器（改变α）探测到的光强分布图形变为椭圆,并且和原点相切,和θ＝0°的图形相比,此时图形的半宽度增加。当入射光的角度θ固定为0°、探测器角度α变化接近180°时光的后向漫射强度最大,其图形为一个圆。比较前向散射和后向漫射的光强分布图可看出光强分布基本上对称。如将两幅     

宁夏河东沙地生物土壤结皮对土壤性质及入渗过程的影响

为了揭示沙漠化治理过程中生物土壤结皮覆盖对土壤入渗过程的影响规律,以宁夏河东沙地人工沙漠治理区4种典型地表覆盖类型：裸沙(BS)、藻类结皮(AC)、藓类结皮(MC)、草本-藓类结皮(H-MC)为研究对象,基于野外双环入渗试验与室内模拟,分析了3种生物土壤结皮覆盖下土壤性质的变化与土壤入渗特征。结果表明：(1)与BS相比,3种结皮覆盖下表层土壤砂粒含量减少2.0%—5.1%,粉粒含量增加3.6%—5.8%,有机质含量增加了5—6倍,AC和MC覆盖下土壤总孔隙度与饱和含水量降低,而H-MC与之相反;(2)平均入渗速率表现为BS>H-MC>AC>MC,1h累计入渗量表现为H-MC>BS>AC>MC,与BS相比,AC、MC和H-MC的初渗速率依次减少了14.3%、37.2%、11.8%,AC、MC的稳渗速率分别降低了14.4%和18.3%,H-MC的稳渗速率增加了4.5%;(3)三种模型中,Kostiakov模型最适用于模拟生物土壤结皮覆盖下土壤水分入渗过程。综上,研究区内不同发育程度生物土壤结皮改变了下层土壤的性质以及土壤的入渗特征,MC与AC阻碍水分入渗...     

脐带间充质干细胞介导TLR4/NF-κB炎症通路及氧化应激改善NAFLD大鼠肝脏损伤作用研究

目的探讨脐带间充质干细胞（hUC-MSCs）对非酒精性脂肪肝病（NAFLD）大鼠肝脏损伤的作用及其与TLR4/NF-κB炎症通路和氧化应激的关系。 方法SD大鼠随机分为3组：正常对照组（NC组）、模型对照组（MC组）和hUC-MSCs治疗组（MC+hUC-MSCs组）。每组大鼠均为10只,分别喂食常规或高糖高脂饲料并给予相应治疗8周,其中MC+hUC-MSCs组每两周尾静脉注射含5×10⁶个hUC-MSCs。检测各组肝指数、谷丙转氨酶（ALT）、谷草转氨酶（AST）、甘油三酯（TG）、胆固醇（TC）、低密度脂蛋白（LDL）、高密度脂蛋白（HDL）和胰岛素抵抗指数（HOMA-IR）。光镜和电镜观察大鼠肝脏组织病理改变,评估NAFLD活动度积分（NAS）;Western Blot法检测大鼠肝脏组织超氧化物歧化酶（SOD）、8-羟基脱氧鸟苷（8-OHdG）、肿瘤坏死因子（TNF-α）、白介素-6（IL-6）Toll样受体4（TLR4）和核因子-κB （NF-κB）蛋白表达。组间比较采用单因素方差分析。 结果干预结束后,（1）NC组TG（0.96±0.29）?mmol/?L、TC（2.23±0.37）mmol/L、LDL（0.71±0.18）mmol/L、HDL（2.95±0.27）mmol/L,与MC组TG（5.79± 0.68）mmol/L、TC（6.08±0.79）mmol/L、LDL（6.06±0.31）mmol/L、HDL（0.75±0.18）?mmol/?L比较差异具有统计学意义（均P < 0.05）;与MC组比较,MC+hUC-MSCs组上述指标差异具有统计学意义（均P < 0.05）。（2）光镜下NC组肝细胞形态正常;MC组出现肝细胞脂肪变性、肝小叶排列不齐及炎症细胞浸润;而MC+hUC-MSCs组肝组织病理改变明显好转。与NC组比较,MC组肝组织NAS升高;与MC组比较,MC+hUC-MSCs组NAS降低[（0.36±0.16）分vs（8.72±0.35）分、（4.78±0.51）分,P < 0.05]。电镜下亦观察到与MC组比较,MC+hUC-MSCs大鼠肝细胞脂肪变性、胞核变形、内质网和线粒体形态异常明显改善。（3）与NC组比较,MC组大鼠TNF-α、IL-6、8-OHdG、TLR4和NF-κB蛋白表达均增高（均P < 0.05）,SOD降低（P?< 0.05）;与MC组比较,MC+hUC-MSCs组大鼠上述指标改善（P < 0.05）。 结论hUC-MSCs通过抑制氧化应激和TLR4/NF-κB而保护NAFLD大鼠肝脏功能。     

Transfer and multiplex immunoblotting of a paraffin embedded tissue

As we transition from genomics to the challenges of the functional proteome, new tools to explore the expression of proteins within tissue are essential. We have developed a method of transferring proteins from a formalin fixed, paraffin embedded tissues section to a stack of membranes which is then probed with antibodies for detection of individual epitopes. This method converts a traditional tissue section into a multiplex platform for expression profiling. A single tissue section can be transferred to up to ten membranes, each of which is probed with different antibodies, and detected with fluorescent secondary antibodies, and quantified by a microarray scanner. Total protein can be determined on each membrane, hence each antibody has its own normalization. This method works with phospho-specific antibodies as well as antibodies that do not readily work well with paraffin embedded tissue. This novel technique enables archival paraffin embedded tissue to be molecularly profiled in a rapid and quantifiable manner, and reduces the tissue microarray to a form of protein array. This method is a new tool for exploration of the vast archive of formalin fixed, paraffin embedded tissue, as well as a tool for translational medicine.     

Composite scaffolds for cartilage tissue engineering

Tissue engineering remains a promising therapeutic strategy for the repair or regeneration of diseased or damaged tissues. Previous approaches have typically focused on combining cells and bioactive molecules (e.g., growth factors, cytokines and DNA fragments) with a biomaterial scaffold that functions as a template to control the geometry of the newly formed tissue, while facilitating the attachment, proliferation, and differentiation of embedded cells. Biomaterial scaffolds also play a crucial role in determining the functional properties of engineered tissues, including biomechanical characteristics such as inhomogeneity, anisotropy, nonlinearity or viscoelasticity. While single-phase, homogeneous materials have been used extensively to create numerous types of tissue constructs, there continue to be significant challenges in the development of scaffolds that can provide the functional properties of load-bearing tissues such as articular cartilage. In an attempt to create more complex scaffolds that promote the regeneration of functional engineered tissues, composite scaffolds comprising two or more distinct materials have been developed. This paper reviews various studies on the development and testing of composite scaffolds for the tissue engineering of articular cartilage, using techniques such as embedded fibers and textiles for reinforcement, embedded solid structures, multi-layered designs, or three-dimensionally woven composite materials. In many cases, the use of composite scaffolds can provide unique biomechanical and biological properties for the development of functional tissue engineering scaffolds.     

Osteochondral tissue cultures: Between limits and sparks,the next step for advanced in vitro models

The increasing demand for reliable preclinical models and to reduce, refine and, if possible, replace animal studies have brought forth the development of complex tissue cultures in different research areas, including the musculoskeletal field. In this paper, we review the literature within last 10 years on the state of progress for in vitro models of osteochondral tissue cultures, taking into account the clinical relevance of the management and treatment of osteochondral lesions. According to the selected research criteria, 35 works, 27 of which with animal tissues and 8 with human tissues, resulted to be relevant for the purposes of this review. Data analyzed revealed a great heterogeneity among the proposed tissue culture models. The anatomical harvesting sites resulted to be mainly the knee stifle joint, both for animal (prevalently bovines) and human tissues derived from joint replacement surgery, and significant heterogeneity among culture conditions and media were found. To date, very few papers have focused on the set up of a reproducible in vitro model, applicable to a variety of studies, thus suggesting a relevant gap to fill in the development of advanced three-dimensional osteochondral culture models.     

Direct noninvasive measurement and numerical modeling of depth-dependent strains in layered agarose constructs

Biomechanical factors play an important role in the growth, regulation, and maintenance of engineered biomaterials and tissues. While physical factors (e.g. applied mechanical strain) can accelerate regeneration, and knowledge of tissue properties often guide the design of custom materials with tailored functionality, the distribution of mechanical quantities (e.g. strain) throughout native and repair tissues is largely unknown. Here, we directly quantify distributions of strain using noninvasive magnetic resonance imaging (MRI) throughout layered agarose constructs, a model system for articular cartilage regeneration. Bulk mechanical testing, giving both instantaneous and equilibrium moduli, was incapable of differentiating between the layered constructs with defined amounts of 2% and 4% agarose. In contrast, MRI revealed complex distributions of strain, with strain transfer to softer (2%) agarose regions, resulting in amplified magnitudes. Comparative studies using finite element simulations and mixture (biphasic) theory confirmed strain distributions in the layered agarose. The results indicate that strain transfer to soft regions is possible in vivo as the biomaterial and tissue changes during regeneration and maturity. It is also possible to modulate locally the strain field that is applied to construct-embedded cells (e.g. chondrocytes) using stratified agarose constructs.     

Low-temperature culturing improves survival rate of tissue-engineered cardiac cell sheets

Assembling three-dimensional (3D) tissues from single cells necessitates the use of various advanced technological methods because higher-density tissues require numerous complex capillary structures to supply sufficient oxygen and nutrients. Accordingly, creating healthy culture conditions to support 3D cardiac tissues requires an appropriate balance between the supplied nutrients and cell metabolism. The objective of this study was to develop a simple and efficient method for low-temperature cultivation (< 37 °C) that decreases cell metabolism for facilitating the buildup of 3D cardiac tissues. We created 3D cardiac tissues using cell sheet technology and analyzed the viability of the cardiac cells in low-temperature environments. To determine a method that would allow thicker 3D tissues to survive, we investigated the cardiac tissue viability under low-temperature culture processes at 20–33.5 °C and compared it with the viability under the standard culture process at 37 °C. Our results indicated that the standard culture process at 37 °C was unable to support higher-density myocardial tissue; however, low-temperature culture conditions maintained dense myocardial tissue and prevascularization. To investigate the efficiency of transplantation, layered cell sheets produced by the low-temperature culture process were also transplanted under the skin of nude rats. Cardiac tissue cultured at 30 °C developed denser prevascular networks than the tissue cultured at the standard temperature. Our novel findings indicate that the low-temperature process is effective for fabricating 3D tissues from high-functioning cells such as heart cells. This method should make major contributions to future clinical applications and to the field of organ engineering.     

Advances in 3D printing of composite scaffolds for the repairment of bone tissue associated defects

The conventional methods of using autografts and allografts for repairing defects in bone, the osteochondral bone, and the cartilage tissue have many disadvantages, like donor site morbidity and shortage of donors. Moreover, only 30% of the implanted grafts are shown to be successful in treating the defects. Hence, exploring alternative techniques such as tissue engineering to treat bone tissue associated defects is promising as it eliminates the above-mentioned limitations. To enhance the mechanical and biological properties of the tissue engineered product, it is essential to fabricate the scaffold used in tissue engineering by the combination of various biomaterials. Three-dimensional (3D) printing, with its ability to print composite materials and with complex geometry seems to have a huge potential in scaffold fabrication technique for engineering bone associated tissues. This review summarizes the recent applications and future perspectives of 3D printing technologies in the fabrication of composite scaffolds used in bone, osteochondral, and cartilage tissue engineering. Key developments in the field of 3D printing technologies involves the incorporation of various biomaterials and cells in printing composite scaffolds mimicking physiologically relevant complex geometry and gradient porosity. Much recently, the emerging trend of printing smart scaffolds which can respond to external stimulus such as temperature, pH and magnetic field, known as 4D printing is gaining immense popularity and can be considered as the future of 3D printing applications in the field of tissue engineering.     

Identification and distribution of thioredoxin-like 2 as the antigen for the monoclonal antibody MC3 specific to colorectal cancer

MC3 is a colorectal cancer (CRC)-specific mAb previously prepared in our laboratory that can detect CRC with high sensitivity and specificity. However, the target antigen for MC3 had not been identified due to technological limitations. In the present study, immunocytochemistry and immunohistochemistry revealed the expression patterns of MC3 antigen (MC3-Ag) in colon cancer cell lines and CRC tissues. Western blotting analysis showed that the MC3 antibody reproducibly recognized two approximately 30 kDa proteins in the total cell lysates of human colon carcinoma cell lines SW480 and HT-29. Using a proteomic approach, we identified two MC3 immunoreactive spots as two isoforms of thioredoxin-like 2 (Txl-2) protein. Further paired immunostaining showed that Txl-2 had the same expression profile as probed by the MC3 antibody. Western blotting also showed that both antibodies could detect the same two bands, further verifying that Txl-2 is the antigen of MC3 antibody. Additionally, tissue arrays revealed the expression patterns of Txl-2 in various normal and cancer tissues. Further analysis showed that Txl-2 mRNA was elevated in 18 cases of CRC tissues compared to paracancerous tissues and adjacent normal tissues.     

Construction of artificial epithelial tissues prepared from human normal fibroblasts and C9 cervical epithelial cancer cells carrying human papillomavirus type 18 genes

One cervical cancer cell line, C9, carrying human papillomavirus type 18 (HPV18) genes that is one of the major etiologic oncoviruses for cervical cancer was characterized. This cell line was further characterized for its capacity related to the epithelial cell proliferation, stratification and differentiation in reconstituted artificial epithelial tissue. Thein vitro construction of three dimensional artificial cervical epithelial tissue has been engineered using C9 epithelial cancer cells, human foreskin fibroblasts and a matrix made of type I collagen by organotypic culture of epithelial cells. The morphology of paraffin embedded artificial tissue was examined by histochemical staining. The artificial epithelial tissues were well developed having multilayer. However, the tissue morphology was similar to the cervical tissue having displasia induced by HPV infection. The characteristics of the artificial tissues were examined by determining the expression of specific marker proteins. In the C9 derived artificial tissues, the expression of EGF receptor, an epithelial proliferation marker proteins for stratum basale was observed up to the stratum spinosum. Another epithelial proliferation marker for stratum spinosum, cytokeratins 5/6/18, were observed well over the stratum spinosum. For the differentiation markers, the expression of involucrin and filaggrin were observed while the terminal differentiation marker, cytokeratins 10/13 were not detected at all. Therefore the reconstituted artificial epithelial tissues expressed the same types of differentiation marker proteins that are expressed in normal human cervical epithelial tissues but lacked the final differentiation capacity representing characteristics of C9 cell line as a cancer tissue derived cell line. Expression of HPV18 E6 oncoprotein was also observed in this artificial cervical epithelial tissue though the intensity of the staining was weak. Thus this artificial cervical epithelial tissue though the intensity of the staining was weak. Thus this artificial epithelial tissue could be used as a useful model system to examine the relationship between HPV-induced cervical oncogenesis and epithelial cell differentiation.     

A novel micro-to-macro approach for cardiac tissue mechanics

For studying cardiac mechanics, hyperelastic anisotropic computational models have been developed which require the tissue anisotropic and hyperelastic parameters. These parameters are obtained by tissue samples mechanically testing. The validity of such parameters are limited to the specific tissue sample only. They are not adaptable for pathological tissues commonly associated with tissue microstructure alterations. To investigate cardiac tissue mechanics, a novel approach is proposed to model hyperelasticity and anisotropy. This approach is adaptable to various tissue microstructural constituent’s distributions in normal and pathological tissues. In this approach, the tissue is idealized as composite material consisting of cardiomyocytes distributed in extracellular matrix (ECM). The major myocardial tissue constituents are mitochondria and myofibrils while the main ECM’s constituents are collagen fibers and fibroblasts. Accordingly, finite element simulations of uniaxial and equibiaxial tests of normal and infarcted tissue samples with known amounts of these constituents were conducted, leading to corresponding tissue stress–strain data that were fitted to anisotropic/hyperelastic models. The models were validated where they showed good agreement characterized by maximum average stress-strain errors of 16.17 and 10.01% for normal and infarcted cardiac tissue, respectively. This demonstrate the effectiveness of the proposed models in accurate characterization of healthy and pathological cardiac tissues.