Theoretical and experimental study of the intensity distribution in biological tissues

Based on the diffusion approximate theory （DA）, a theoretical model about the distribution of the intensity of a narrow collimation beam illuminating on a semi-lnfinite biological tissue is developed. In order to verify the correctness of the model, a novel method of measuring the distributions of the intensity of light in Intralipid-10% suspension at 650 nm is presented and ts of the distributions of the distance-dependent intensity of scattering light in different directions are made. The investigations show that the results from our diffusion model are in good agreement with the experimental results beyond and in the areas around the light source, and the distance-dependent intensity in the incident direction attenuates approximately in the exponential form. Furthermore, our theoretic results indicate the anisotropic characteristics of the intensity in different directions of scattering light inside the biological tissue.

NEW PARAMETER FOR DESCRIBING AND ANALYZING THE OPTICAL-ANISOTROPIC PROPERTIES OF BIOLOGICAL TISSUES

To characterize the degree of similarity inherent to parameters of the optically uniaxial birefringent protein-fibril networks of biological tissues,a new parameter-complex degree of mutual anisotropy-has been offered.The technique of polarization measuring the coordinate distributions of the complex degree of mutual anisotropy of biological tissues has been developed.It has been shown that statistical approach to the analysis of complex degree of mutual anisotropy distributions for biological tissues in various morphological and physiological states and for different optical thicknesses appears to be more sensitive and efficient in differentiation of physiological state,as compared to investigations of complex degree of mutual polarization in the corresponding laser images.

QUANTITATIVE MUELLER MATRIX POLARIMETRY TECHNIQUES FOR BIOLOGICAL TISSUES

We propose and conduct both the rotating linear polarization imaging(RLPI)and Mueller matrix transformation(MMT)measurements of different biological tissue samples,and testify the capability of the Mueller matrix polarimetry for the anisotropic scattering media.The independent parameters extracted from the RLPI and MMT techniques are compared and analyzed.The tissue experimental results show that the parameters are closely related to the structural characteristics of the turbid scattering media,including the sizes of the scatterers,the angular distribution and order of alignment of thefibers.The results and conclusions in this paper may provide a potential method for the detection of precancerous and early stage cancerous tissues.Also,such studies represent the Mueller matrix transformation procedure which results in a set of parameters linking up the Mueller matrix elements to the structural and optical properties of the media.

Heat transport properties within living biological tissues with temperature-dependent thermal properties

Understanding of the heat transport within living biological tissues is crucial to effective heat treatments. The heat transport properties of living biological tissues with temperature-dependent properties are explored in this paper. Taking into account of variable physical properties, the governing equation of temperature is first derived in the context of the dualphase-lags model(DPL). An effective method, according to the Laplace transform and a linearization technique, is then employed to solve this nonlinear governing equation. The temperature distribution of a biological tissue exposed to a pulsed heat flux on its exterior boundary, which frequently happens in various heat treatments, is predicted and analyzed. The results state that a lower temperature can be predicted when temperature dependence is considered in the heating process.The contributions of key thermal parameters are different and dependent on the ratio of phase lag and the amplitude of the exterior pulsed heat flux.

Construction of the tissue engineering seed cells(HaCaT-EGF) and analysis of its biological characteristics

Objective:To construct the tissue engineering seed cell(HaCaT cell line) with stable expression of the human epidermal growth factor(EGF),and analyze the changes of its biological characteristics.Methods:PCDNA3.1-EGF eukaryotic expression vector was transferred into HaCaT cell,and G418 was utilized to select the HaCaT-EGF cell line.Using an inverted microscope,PCR,ELISA method to detect the changes of the cell morphology,the expression of the ECF gene and protein,and the mRNA expression levels of apoptosis related molecule Caspase-3,the cell cycle related protein cyclin D1.Results:The mRNA expression levels of the obtained HaCaT-ECF cell were more than 100 times higher than the level of ordinary HaCaT cell.The colony of the HaCaT-EGF cells was more focused and tight compared to the empty vector transfected HaCaT cells and normal HaCaT cells.The expression levels of apoptotic factor Caspase-3 and cyclin Dt in HaCaT-EGF cell were significantly higher than those in the empty vector HaCaT- pcDNA3.1 cell,and the differences were statistically significant(P<0.01),but there was no significant difference compared to the normal HaCaT cells(P>0.05).Conclusions: HaCaT-EGF cell can continuously secrete ECF,and the biological characteristic is stable.It can be used for tissue engineering experiment and is an ideal seed cell for constructing tissue engineered skin.

Measurement of the Elasticity of Biological Soft Tissue of Finite Thickness

Elasticity is of profound significance to evaluating the function of a biological soft tissue. When the elasticity of a tissue is macroscopically changed, it means that the biological function of the tissue is abnormal and some disease or injury may occur. In the present work, an elastometer is developed to measure the elasticity of biological soft tissues. The measurement is based on the indentation method and the force is measured by the bending of the cantilever. The force-indentation data of the soft tissue is experimentally measured by this elastometer and Young＇s modulus of the tissue is calculated using the Hertz-Sneddon model. For comparison, a numerical model for the indentation method is established using the finite element method. The difference between the actual modulus and the measured modulus is discussed. The effect of the thickness of the specimen on the measurement is investigated. Young＇s moduli of beef, porcine liver and porcine kidney are experimentally measured. The results indicate that our elastometer is effective in measuring Young＇s modulus of a soft tissue quantitatively.

Recent Advances in Soft Biological Tissue Manipulating Technologies

Biological soft tissues manipulation,including conventional(mechanical)and nonconventional(laser,waterjet and ultrasonic)processes,is critically required in most surgical innervations.However,the soft tissues,with their nature of anisotropic and viscoelastic mechanical properties,and high biological and heat sensitivities,are difficult to manipulated.Moreover,the mechanical and thermal induced damage on the surface and surrounding tissue during the surgery can impair the proliferative phase of healing.Thus,understanding the manipulation mechanism and the resulted surface damage is of importance to the community.In recent years,more and more scholars carried out researches on soft biological tissue cutting in order to improve the cutting performance of surgical instruments and reduce the surgery induced tissue damage.However,there is a lack of compressive review that focused on the recent advances in soft biological tissue manipulating technologies.Hence,this review paper attempts to provide an informative literature survey of the state-of-the-art of soft tissue manipulation processes in surgery.This is achieved by exploring and recollecting the different soft tissue manipulation techniques currently used,including mechanical,laser,waterjet and ultrasonic cutting and advanced anastomosis and reconstruction processes,with highlighting their governing removal mechanisms as well as the surface and subsurface damages.

Study and Modeling of Human Biological Tissue Exposed to High Frequency Electromagnetic Waves

The main objective of this proposed article is to provide explanations to justify the validity of the results of the studies of the interaction between the electromagnetic fields and the human body. It can also find direct applications in the characterization and modeling of the macroscopic electrical properties of the biological media for assessing the effects of fields induced by electromagnetic radiation sources in the human body to set up new standards on the Human exposure to electromagnetic fields. To do this, we have taken into account the different physical phenomena of propagation of a hyper-frequency electromagnetic plane wave and on the other hand, the experimental values in order to model the electrical behavior of human biological tissues based on an equivalent electronic circuit model composed of capacities, resistance and reel, which assimilates the biological tissues of the skin, grease, blood. This model using the characteristic impedance of the dielectric support makes it possible to evaluate the voltage induced by the electromagnetic waves of the hyper-frequencies in the studied biological system. The results of the simulations obtained from computer tools demonstrate that the hyper-frequency electromagnetic waves can result in an elevation of the electrical potential of the biological tissues. Despite this potential is a decreasing function of the penetration depth.

MEASUREMENT OF THE DIELECTRIC PROPERTIES OF BIOLOGICAL TISSUE

An open-ended coaxial line reflection method especially suitable for meas-uring the dielectric properties of biological tissue in vivo is described.This method offersthe advantage of not requiring any special preparation of the samples to be measured but aclose contact with the open end of a coaxial line.It is,therefore,very convenient to acquirea large number of measurement data in broad band rapidly.The method may also be usedto measure the properties of other substances.The measuring system consists of a networkanalyzer controlled by a microcomputer and calibrated by using ANA procedure to elimi-hate the influnce of error network introduced by the adapter,some connectors,etc.In or-der to reach higher accuracy,the iterative method is used to determine the parameters ofthe equivalent circuit.Measurements of permeativities of some living tissues have been per-formed in the frequency band of 0.5-2GHz.Compared with the results known in somepapers,the validity of this method has been confirmed.The difference in dielectric proper-ties between living and dead tissues,and the tissue permeativites(ε)versus frequency andduration of measurement after death have also been measured.

Coagulation and ablation of biological soft tissue byquantum cascade laser with peak wavelength of 5.7μm

Molecules such as water,proteins and lipids that are contained in biological tissue absorb mid-infrared(MR)light,which allows such light to be used in laser surgical treatment.Esters,amides and water exhibit strong absorption bands in the 5-7μm wavelength range,but at present there are no lasers in clinical use that can emit in this range.Therefore,the present study focused on thequantum cascade laser(QCL),which is a new type of semiconductor laser that can emit at MIRwavelengths and has recentiy achieved high output power.A high-power QCL with a peakwavelength of 5.7μm was evaluated for use as a laser scalpel for ablating biological soft tissue.The interaction of the laser beam with chicken breast tissue was compared to a conventional CO_(2) laser,based on surface and cross-sectional images.The QCL was found to have sufficient power to ablate soft tissue,and its coagulation,carbonization and ablation effects were similar to those forthe CO_(2) laser.The QCL also induced comparable photothermal effects because it acted as apseudo-continuous wave laser due to its low peak power.A QCL can therefore be used as an effective laser scalpel,and also offers the possibility of less invasive treatment by targeting specificabsorption bands in t he MIR region.

Anisotropic Constitutive Modeling of Compressible Biological Tissue

The anisotropic continuum stored energy density (ACSED) functional is applied for accurate constitutive modeling of biological tissues and finite element implementation without the isochoric—volumetric split, the anisotropic—isotropic split, or the anisotropic invariant split. Related stress and elasticity tensors in the reference and current configurations are worked out. A new kinematic model is derived based on the tangent Poisson’s ratio as a cubic polynomial function of stretch. The ACSED model, along with the kinematic model, accurately fits uniaxial extension test data for compressible human skin, bovine articular cartilage, and human aorta samples.

Simple and sensitive determination of sparfloxacin in pharmaceuticals and biological samples by immunoassay

Plasma quinolone concentrations are not routinely measured in clinical practice.However,in order to optimize quinolone treatment,monitoring of plasma concentrations could sometimes be useful particularly in critically ill patients.In this study,anti-sparfloxacin antibody was obtained by immunizing rabbits with sparfloxacin conjugated with bovine serum albumin using isobutyl chloroformate method.After the assay procedure was optimized,the standard curve of sparfloxacin was established.The practical measuring range of the competitive ELISA extended from 5 ng/mL to 2 mg/mL.The recovery rates and coefficients of variation for rat plasma,urine and tissues were 87.7-106.2% and 4.8-15.3%,respectively.To demonstrate the potential of the ELISA,a preliminary pharmacokinetics and tissue distribution study of sparfloxacin in rats and quantitative analysis of sparfloxacin in several pharmaceuticals were performed and compared with high-performance liquid chromatography(HPLC).The experimental data indicated that the proposed method would be a valuable tool in therapeutic drug monitoring(TDM) for sparfloxacin.

Temperature rise induced by an annular focused transducer with a wide aperture angle in multi-layer tissue

In order to improve the operability and accuracy of high-intensity focused ultrasound （HIFU）, an annular focused transducer, whereby a B-ultrasound probe is placed in its center, is used to realize the real time monitoring and control of the treatment. In this paper, the spheroidal beam equation （SBE） was used to calculate the sound lield by an annular focused transducer with a wide aperture angle to first derive the heat deposition and the Pennes equation was used to calculate the temperature field in multi-layer tissue. We studied the effect of different parameters on the temperature of the tissues. The result shows that the focal length has a significant influence on both maximum liver temperature rise and skin temperature rise, and both increase with the increase in the focal length. When the frequency increases, the temperature rise first undergoes a rapid increase before gradually reaching a maximum, and then finally decreasing. The temperature rise increases while the inner radius decreases or the sound pressure increases. By choosing suitable parameters, the proper temperature rise both on the target tissue and skin via an annular tbcused transducer with a wide aperture angle can be obtained.

Analysis, Sources and Study of the Biological Consequences of Electromagnetic Pollution

The actions and health effects of electromagnetic fields in the radio frequency (RF) domains, referred to as radio frequencies and HV transmission networks have been studied for several decades. Following the appearance of questions and debates within the population, the actions and potential effects of radiofrequency and HV transport networks on health, in connection with the development of new wireless technologies, are generating a certain revival of interest. Thus, the increasing exposure to electromagnetic fields and the concerns of the public have led health organizations to undertake large-scale research programs to respond to the concerns expressed. These research programs have contributed to significantly increasing the number of studies on the actions and effects of electromagnetic pollution as well as their consequences on living beings. The objective of our research is focused on the analysis, sources, and study of the biological consequences of electromagnetic pollution. To do this, we have used physical laws and theorems, in particular Maxwell-Ampère, Maxwell-Gauss, Maxwell-Faraday, and Ohm’s law, to model the interactions between electromagnetic fields and living matter. In this article we have chosen the approach based on the electrical model of human biological tissue, taking into account on the one hand the physical phenomena of the propagation of an electromagnetic microwave plane wave in the range from 0 to 300GHz and on the other hand, the experimental values to simulate the relaxations α, β and γ and the impedance of the biological tissue faced with the variation of the frequency of propagation of the electromagnetic waves to identify the biological consequences relating thereto. The results obtained in the literature show the linear dependence of bio-impedance on frequency, these observations suggest that the tissue can be physiologically stressed at high frequencies. This can cause biological consequences for humans. The 2D simulation based on the proposed model has been developed as well as the verification of the consistency of the different mathematical models, by comparing the fractal dimensions of the results of the program with those of the figures obtained experimentally.

生物3D打印仿生支架促进肩袖损伤后的愈合

背景:大多数肩袖损伤发生于冈上肌腱,由于肌腱组织缺少血管以及肩袖复杂的解剖结构,临床治疗效果非常有限。组织工程技术和干细胞生物学的快速发展为提高肌腱修复质量带来了新的希望。目的:通过生物3D打印技术制备人脐带间充质干细胞/甲基丙烯酸酐化明胶复合支架,观察该支架修复肩袖损伤的效果。方法:(1)体外细胞实验:制备明胶微载体,将人脐带间充质干细胞接种于明胶微载体表面构建组织工程化干细胞。制备甲基丙烯酸酐化明胶水凝胶打印墨水,使用甲基丙烯酸酐化明胶水凝胶打印墨水重悬组织工程化干细胞,放入3D打印机的生物墨水容器中进行打印,蓝光照射固化5 min后即得人脐带间充质干细胞/甲基丙烯酸酐化明胶复合支架。通过死活染色、CCK-8实验检测支架内人脐带间充质干细胞的活性。(2)动物体内实验:采用随机区组设计方法将24只SD大鼠随机4组,每组6只:正常组不进行任何处理,肩袖损伤组、单纯支架组、细胞支架组建立冈上肌腱撕裂的肩袖损伤模型,单纯支架组、细胞支架组造模后分别将甲基丙烯酸酐化明胶支架、人脐带间充质干细胞/甲基丙烯酸酐化明胶复合支架植入肌腱损伤处。术后4周,分别进行大鼠行为学测试及肩袖冈上肌腱组织学病理组织形态观察。结果与结论:(1)体外细胞实验:死活染色结果显示,明胶微载体可减轻3D打印过程对人脐带间充质干细胞造成的损伤,随着培养时间的延长,支架内的人脐带间充质干细胞存活率升高;CCK-8实验结果显示,随着培养时间的延长,支架内的人脐带间充质干细胞活性无明显变化。(2)动物体内实验:行为学测试结果显示,相较于肩袖损伤组、单纯支架组,细胞支架组大鼠四肢运动功能明显改善;肩袖冈上肌腱苏木精-伊红与Masson染色结果显示,相较于肩袖损伤组、单纯支架组,细胞支架组肌纤维排列较规律,无明显的炎性细胞浸润,胶原容积百分比降低;免疫荧光染色结果显示,相较于肩袖损伤组、单纯支架组,细胞支架组肩袖冈上肌腱内白细胞介素6、肿瘤坏死因子α蛋白表达明显降低。(3)结果表明,生物3D打印的人脐带间充质干细胞/甲基丙烯酸酐化明胶复合支架可促进肩袖损伤组织修复再生。

PLGA/赖氨酸接枝氧化石墨烯纳米粒子复合支架对MC3T3细胞成骨分化的影响

背景:骨损伤后如何有效促进骨再生和骨重建一直是临床骨修复研究中的关键问题,利用生物和降解材料搭载生物活性因子在骨修复中具有优秀的应用前景。目的:探究赖氨酸接枝氧化石墨烯(LGA-g-GO)纳米粒子改性的聚乳酸-羟基乙酸共聚物(PLGA)复合支架对成骨分化及新骨形成的影响。方法:将PLGA溶于二氯甲烷中,利用溶剂挥发法制备PLGA支架;将氧化石墨烯均匀分散于PLGA溶液中制备PLGA/GO复合支架;利用化学接枝法制备LGA-g-GO纳米粒子,将LGA-g-GO纳米粒子按不同的质量比(1%,2%,3%)与PLGA共混构建出PLGA/LGA-g-GO复合支架。表征5组支架的微观形貌、亲水性、蛋白吸附能力。将MC3T3细胞分别接种于5组支架表面,检测细胞增殖与成骨分化情况。结果与结论:①扫描电镜下可见PLGA支架表面光滑平坦,其余4组支架表面粗糙,并且随着LGA-g-GO纳米粒子加入量的增加,复合支架的表面粗糙程度加重;PLGA/LGA-g-GO(3%)复合支架的水接触角低于其他4组支架(P<0.05);PLGA/LGA-g-GO(1%,2%,3%)复合支架的蛋白吸附能力强于PLGA、PLGA/GO支架(P<0.05);②CCK-8检测显示,PLGA/LGA-g-GO(2%,3%)复合支架可促进MC3T3细胞的增殖;碱性磷酸酶染色与茜素红染色显示,PLGA/LGA-g-GO(2%,3%)组细胞碱性磷酸酶活性高于其他3组(P<0.05),PLGA/GO组、PLGA/LGA-g-GO(1%,2%,3%)组钙沉积多于PLGA组(P<0.05);③结果表明,PLGA/LGA-g-GO复合支架能够促进成骨细胞的增殖和成骨分化,有利于骨损伤后的骨再生和骨重建。

Plasma matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 as biomarkers of ulcerative colitis activity

AIM:Overexpression of mucosal metalloproteinases(MMP) has been demonstrated recently in inflammatory bowel disease.Their activity can be counterbalanced by the tissue inhibitor of metalloproteinases(TIMP).The aim of this study was to evaluate the effect of ulcerative colitis(UC)on MMP- 1 and TIMP-1 plasma concentrations,as two possible biomarkers of the disease activity. METHODS:MMP-1 and TIMP-1 plasma concentrations were measured with an enzyme immunoassay in 16 patients with endoscopically confirmed active UC. RESULTS:Plasma concentrations of both MMP-1(13.7±0.2 ng/ml)and TIMP-1(799±140 ng/ml)were significantly elevated in UC patients in comparison to healthy controls (11.9±0.9 ng/ml and 220±7 ng/ml respectively).There was no correlation between TIMP-1 and MMP-1 concentrations (r=0.02).TIMP-1 levels revealed significant positive correlations with scored endoscopic degree of mucosal injury, disease activity index and clinical activity index values as well as C-reactive protein concentration.There was no correlation between MMP-1 and laboratory,clinical or endoscopic indices of the disease activity.CONCLUSION: These results confirm the role of both MMP- 1 and TIMP-1 in the pathogenesis of ulcerative colitis. However only TIMP-1 can be useful as a biomarker of the disease activity, demonstrating association with clinical and endoscopic pictures.

Differentiation of mesenchymal stem cells into neuronal cells on fetal bovine acellular dermal matrix as a tissue engineered nerve scaffold

The purpose of this study was to assess fetal bovine acellular dermal matrix as a scaffold for supporting the differentiation of bone marrow mesenchymal stem cells into neural cells fol-lowing induction with neural differentiation medium. We performed long-term, continuous observation of cell morphology, growth, differentiation, and neuronal development using several microscopy techniques in conjunction with immunohistochemistry. We examined speciifc neu-ronal proteins and Nissl bodies involved in the differentiation process in order to determine the neuronal differentiation of bone marrow mesenchymal stem cells. The results show that bone marrow mesenchymal stem cells that differentiate on fetal bovine acellular dermal matrix display neuronal morphology with unipolar and bi/multipolar neurite elongations that express neuro-nal-speciifc proteins, includingβIII tubulin. The bone marrow mesenchymal stem cells grown on fetal bovine acellular dermal matrix and induced for long periods of time with neural differen-tiation medium differentiated into a multilayered neural network-like structure with long nerve ifbers that was composed of several parallel microifbers and neuronal cells, forming a complete neural circuit with dendrite-dendrite to axon-dendrite to dendrite-axon synapses. In addition, growth cones with filopodia were observed using scanning electron microscopy. Paraffin sec-tioning showed differentiated bone marrow mesenchymal stem cells with the typical features of neuronal phenotype, such as a large, round nucleus and a cytoplasm full of Nissl bodies. The data suggest that the biological scaffold fetal bovine acellular dermal matrix is capable of supporting human bone marrow mesenchymal stem cell differentiation into functional neurons and the subsequent formation of tissue engineered nerve.

Varying of up-conversion nanoparticles luminescence from the muscle tissue depth during the compression

The current work is focused on the study of optical clearing of skeletal muscles under local compression.The experiments were performed on in vitro bovine skeletal muscle.The time dependence of optical clearing was studied by monitoring the luminescence intensity of NaYF_(4)∶Er,Yb upconverting particles located under tissue layers.This study shows the possibility to use upconverting nanoparticles(UCNPs)both for studying the dynamics of the optical clearing of biological tissue under compression and to detect moments of cell wall damage under excessive pressure.The advantage of using UCNPs is the presence of several bands in their luminescence spectra,located both at close wavelengths and far apart.